JPH09227660A - Biodegradable polyester having regular reticular structure and production of its molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a biodegradable polyester excellent in alkali, acid, water and organic solvent resistances and disintegrated by lipase by using a specified polyhydric alcohol and a specified aliphatic dicarboxylic acid as the constituents. SOLUTION: This polyester comprises a polyhydric alcohol based on a trihydric alcohol and an aliphatic dicarboxylic acid. The aliphatic dicarboxylic acid comprises at least 65mol% at least one compound (a linear aliphatic dicarboxylic acid) selected among linear aliphatic dicarboxylic acids represented by the formula (wherein (n) is 6-15), anhydrides thereof and esters thereof. The polyester has excellent alkali, acid, water and organic solvent resistances, can be disintegrated with lipase, and can be molded into films, sheets, etc., excellent in the above-mentioned properties.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a biodegradable polyester and a method for producing a molded article using the same. More specifically, the present invention relates to a biodegradable polyester having a regular network structure that is disintegrated by lipase, and a method for producing a molded article using the same. More specifically, it has excellent alkali resistance, acid resistance, water resistance, and organic solvent resistance, and has a regular network structure that is disintegrated by lipase, and a biodegradable polyester, and a film or sheet molding using the same. A method of manufacturing a body.

[0002]

BACKGROUND ART Today, plastics are used in all fields and are one of the essential materials for daily life. However, plastics do not rot after use, and because of the surface development of their additives and the generation of harmful substances during landfilling and incineration, they cause serious problems in terms of environmental destruction. For this reason, development of new biodegradable synthetic resins and polymers is expected. Synthetic aliphatic polyesters have long attracted attention as typical biodegradable plastics (see, for example, Y. Tokiwa).
et al. , Hydrolysis of po
lyesters by lipases, Natu
Re, 270 (1977) 76. And A. C. A
lbertson, Degradable poly
mers, J.M. Macromol. Sci. Pure
Appl Chem. , A30 (1993) 75
7). However, these synthetic aliphatic polyesters have drawbacks in practical thermal and mechanical properties.

[0003] In order to compensate for these drawbacks, a small amount of trivalent or higher polycarboxylic acid, polyhydric alcohol or polyhydric hydroxycarboxylic acid (hereinafter abbreviated as trifunctional or higher functional compound) is added to the raw material of the polyester to partially reduce the amount. An attempt to introduce a crosslinked structure to increase the molecular weight is disclosed in JP-A-3-97723. However, it is difficult to uniformly and regularly scatter the crosslinked structure formed by the trifunctional or higher compound throughout the polyester, and it is difficult to obtain a polyester having a nonuniform and irregular structure with uniform physical properties. Was. Similarly, a method for producing a polyester having a relatively high molecular weight by introducing a compound having three or more functional groups and then reacting a small amount of polyisocyanate for the purpose of increasing the molecular weight of the polyester to obtain a urethane bond-containing polyester,
For example, JP-A-5-170891, JP-A-5-29
No. 5071 discloses this. However, there remains a problem that the polyester is easily discolored and a toxic unreacted polyisocyanate remains in the urethane bond-containing polyester. In these production methods, tri- or more functional compounds required for the synthesis of a high-molecular-weight polyester have a very low possibility of producing a gel in the final polyester, and thus the amount used is extremely small. That is, since the amount of the trifunctional or higher functional compound used is limited, the resulting polyester has a limited molecular weight and at the same time has no regularity in the chemical structure, so that the molded product has a partial difference in physical properties. . Further, the problems of water resistance, organic solvent resistance, acid resistance and alkali resistance, which are expected when actually used as a material, have not been sufficiently solved.

[0004] Polyesters containing aromatics are water-resistant,
It is a heat-resistant resin having excellent acid resistance, alkali resistance, and organic solvent resistance, and helps to solve some of the above problems. Recently, an aromatic polymer having a branched structure using glycol and aromatic carboxylic acid has been studied (see, for example, T.W.
Kiyotukuri et al. , Network
k polyester film from gly
cerol and carboxylic acid
s, Polymer Int. , 33 (1994)
1). However, this aromatic-containing polyester having a branched structure is intended to improve mechanical strength and heat resistance.
It shows little biodegradability compared to aliphatic polyesters. Moreover, even if the aromatic compounds are decomposed over a long period of time, these aromatic compounds cannot be expected as biodegradable polyesters because many of them are toxic.

[0005] As another aliphatic polyester having good biodegradability, LACEA (manufactured by Mitsui Toatsu Chemicals, Inc.) is an example of a synthetic polyester obtained by directly polycondensing lactic acid and glycolic acid. Modification and polymerization methods have been studied for the purpose of increasing the molecular weight (for example, disclosed in JP-A-8-3293), and synthetic polyesters having a functional group such as an amide bond or an epoxy group introduced into the polyester. Are also promising as biodegradable polymers. However, it is difficult for all of them to have excellent heat resistance, high mechanical strength, transparency, water resistance, acid resistance, alkali resistance, and solvent resistance.

[0006]

As described above, by increasing the molecular weight of the aliphatic polyester, biodegradability is achieved while imparting excellent water resistance, acid resistance, alkali resistance, organic solvent resistance and transparency. It was difficult to maintain even. An object of the present invention is to provide a biodegradable polyester which solves these problems by focusing on the chemical structure of the polyester and a technique for producing a molded article using the same.

[0007]

As a result of intensive efforts, the present inventors have melt-polymerized a polyester prepolymer from a polyhydric alcohol and a specific aliphatic dicarboxylic acid and dissolved it in a solvent to obtain a prepolymer solution. By pouring into a mold and solid-phase polymerization after removing the solvent from this solution or by polymerizing while removing the solvent from this solution, a regular network structure in which polyhydric alcohol and aliphatic dicarboxylic acid are chemically bonded alternately is formed. Has successfully synthesized aliphatic polyesters. Furthermore, they have found that the obtained polyester not only exhibits biodegradability, but also exhibits excellent properties against the above-mentioned problems, and has reached the present invention. The present invention
It has the following configuration. [1] A polyester comprising a polyhydric alcohol having a trihydric alcohol as a main component and an aliphatic dicarboxylic acid as constituent components, wherein the aliphatic dicarboxylic acid has the formula (1)
Containing at least 65 mol% of one or more kinds of compounds selected from among the linear aliphatic dicarboxylic acids represented by (1) or their acid anhydrides or acid esters thereof (collectively referred to as linear aliphatic dicarboxylic acids) A biodegradable polyester having a regular network structure characterized by being an aliphatic dicarboxylic acid.

Embedded image Formula (1) (where n = 6 to 15) [2] The linear aliphatic dicarboxylic acid is selected from the group of linear aliphatic dicarboxylic acids in which n in the formula (1) is 8 to 12 A biodegradable polyester having a regular network structure according to the item [1], which is a selected compound. [3] Polyester obtained by melt-polymerizing a polyhydric alcohol containing a trihydric alcohol as a main component and an aliphatic dicarboxylic acid having 6 to 15 carbon atoms at 120 to 270 ° C. for 30 to 240 minutes in an inert gas atmosphere. The prepolymer is dissolved in a solvent to form a solution, which is then poured into a mold (a) or cast into a mold release product, and the solvent is distilled off.
It has a regular network structure characterized by carrying out a solid-state polymerization reaction at 0 ° C., or injecting it into a mold (b) or casting it in a mold-releasing body, and carrying out polymerization while distilling off the solvent at 50-350 ° C. A method for producing a biodegradable polyester molding. [4] A biodegradable polyester molding having a regular network structure according to the above item [3], characterized in that the aliphatic dicarboxylic acids include linear aliphatic dicarboxylic acids represented by the formula (1). Body manufacturing method. Hereinafter, this content will be described in more detail.

The polyhydric alcohol component used in the present invention comprises:
It is an essential component for increasing the molecular weight of the polyester by forming a crosslinked structure, and serves as a base connecting the acid components. The trihydric alcohol used in the present invention easily undergoes esterification and transesterification reactions, and even if it is reacted at a high temperature or for a long time for the purpose of increasing the reaction rate, thermal deterioration of the raw material and the product or local gelation. The reaction is easy to control because it is difficult to generate a product. The proportion of the trihydric alcohol used in the polyhydric alcohol is 50 mol% or more, preferably 80 mol% or more,
More preferably, it is 95 mol% or more. If the amount used is less than the lower limit, the biodegradability and reactivity of the resulting polyester will decrease. As a specific trihydric alcohol,
Glycerol, trimethylolpropane, trimethylolethane, 1,2,6-hexatriol and the like can be mentioned. Among them, glycerol is the most preferable in view of synthesizing a polyester having a regular network structure with high symmetry and high economy. In particular, the effect of the present invention is greater when glycerol is 60 mol% or more with respect to the total trihydric alcohol. The trihydric alcohol used in the present invention may be a mixture of two or more kinds.

The polyhydric alcohol used in the present invention includes:
A small amount of tetravalent alcohol and diol may be mixed if necessary. Pentaerythritol as tetrahydric alcohol, ethylene glycol as diol, 1,
4-butanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, 2,2-diethyl-
1,3-propanediol, 2,2-dimethyl-1,3
-Propanediol, 2-butyl-2-ethyl-1,3
-Propanediol can be illustrated. Further, butanol, propanol, ethanol and methanol can be used for terminating the polymerization.

The aliphatic dicarboxylic acids will be described.
This is a component that links polyhydric alcohols. By alternately reacting the dicarboxylic acids with the polyhydric alcohol, a polyester having a regular network structure is produced. As the aliphatic dicarboxylic acid used in the present invention, an aliphatic dicarboxylic acid, an aliphatic dicarboxylic acid anhydride and an aliphatic dicarboxylic acid ester are used, and among them, the aliphatic dicarboxylic acid is preferable. Further, in the polyester of the present invention, the number of carbon atoms represented by the formula (1) is 6 to 1
5, preferably 13 to 13, more preferably 8 to 12 linear aliphatic dicarboxylic acids are particularly suitable. In this carbon number range, the esterification and transesterification reactivity is better, alkali resistance, acid resistance, water resistance,
Excellent performance that simultaneously satisfies solvent resistance and biodegradability. If it is out of this range, the above-mentioned various properties cannot be satisfied at the same time, and if it is less than the lower limit, the reactivity and biodegradability are remarkably deteriorated, and if it exceeds the upper limit, the effect of biodegradability is small.

The aliphatic dicarboxylic acids used in the present invention are specifically adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid and pentadecane. Examples thereof include diacids, and also acid anhydrides and esters thereof. Of these, linear aliphatic dicarboxylic acids are preferable, and suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, and their acid anhydrides and esters are particularly preferable. The amount of the linear aliphatic dicarboxylic acid used is preferably at least 65 mol%, more preferably at least 75 mol%, based on 100 mol% of all dicarboxylic acids used. When the proportion of the total linear aliphatic dicarboxylic acid is small, the reaction takes a long time, and it is difficult to obtain a large effect on the biodegradability of the obtained polyester.

In addition to the above linear aliphatic dicarboxylic acids, other dicarboxylic acids may be added to the aliphatic dicarboxylic acids. Other dicarboxylic acids preferably used include linear aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid and hexadecanedioic acid, branched aliphatic dicarboxylic acids such as methylsuccinic acid and 2-methylpentanedioic acid. Examples thereof include acids, 3-methylpentanedioic acid and 2-methylhexanedioic acid, and cyclohexanedicarboxylic acid which is an alicyclic dicarboxylic acid.

In the present invention, if necessary, compounds other than the above-mentioned raw materials can be added. For example, polycarboxylic acids or polyfunctional hydroxycarboxylic acids, and monocarboxylic acids such as octylic acid and acetic acid can be added. The trivalent or higher polycarboxylic acid includes 1,2,3-
Examples of propanetricarboxylic acid, 1,2,3,4-butanetetracarboxylic acid and polyhydric hydroxycarboxylic acid include tartaric acid, marlic acid, bishydroxymethylpropionic acid and the like. Further, an aromatic compound can be added within a range that does not change the performance of the polyester.

The polyester of the present invention can be obtained by synthesizing a polyester prepolymer from a raw material, dissolving it in a solvent, and then injecting it into a mold or casting it in a mold release body, and by any one of the following two methods. it can. Method 1: Method of solid-phase polymerizing polyester prepolymer after distilling solvent from solution, Method 2: Method of polymerizing while distilling solvent from solution Final polyester surface is smooth, and solvent is distilled inside Method 1 is more preferable because it is difficult for holes and swelling to occur.

In the synthesis of the polyester prepolymer, the carboxyl group of the aliphatic dicarboxylic acid is in the range of 92 to 108 equivalents, preferably 97 to 103 equivalents, more preferably 99 to 101 equivalents based on 100 equivalents of hydroxyl groups of the trihydric alcohol. It is better to react with. Outside of this range, not only the reaction of the following polyester having a regular network structure does not proceed, but also the water resistance, acid resistance and alkali resistance deteriorate.

A catalyst is not always necessary for this reaction, but a known esterification catalyst and transesterification catalyst may be used. For example, specific examples include titanium, antimony, tin, lead, and germanium-based catalysts. The reaction is carried out in an inert gas atmosphere at 120 to 270 ° C., preferably 1
It is performed at 40 to 250 ° C. for 30 to 240 minutes. As the inert gas, nitrogen gas is industrially preferable. When the esterification reaction and the transesterification reaction are performed, if the temperature is lower than the lower limit temperature, the esterification and the transesterification reaction are difficult to occur, and if the temperature is higher than the upper limit temperature, rapid crosslinking reaction and thermal decomposition reaction may locally occur.

The polyester prepolymer obtained is 3
Average of 2 total alcohols and aliphatic dicarboxylic acids
To 40 molecules, preferably 3 to 20 molecules, more preferably 3 to 14 molecules, and the number average molecular weight thereof is 200 to 8000, preferably 300 to 600.
0, more preferably in the range of 300 to 3000. If it is less than the lower limit of the range, the reaction of the polyester having a regular network structure takes time and does not reach a high molecular weight. If it exceeds the upper limit of the range, it gels and does not dissolve in the solvent.

The use of a solvent in the present invention is that the polyester prepolymer is dissolved and the prepolymer is formed into a desired shape by the method 1, and the solid phase polymerization is conducted after the solvent is distilled off. It is an indispensable means for avoiding local generation of gels and rapidly polymerizing polyester having a regular network structure. Further touch on solvents suitable for each technique. Suitable solvents for Method 1 are
Any type can be used as long as it can dissolve the prepolymer. Considering safety in the work of dissolving the polyester prepolymer, it is preferable that this solvent dissolves the polyester prepolymer at a liquid temperature as close as possible to room temperature, and 160 ° C. or less, preferably 120 ° C. or less after molding the target molded body. What can be rapidly distilled off from the polyester prepolymer at a low temperature of ℃ or less is preferable. The solvent suitable for the method 2 is preferably a solvent capable of simultaneously dissolving a relatively low molecular weight polyester prepolymer and a polyester forming a high molecular weight regular network structure. In order to promote the esterification or transesterification reaction while dissolving each polyester, this solvent needs to activate the movement of the polyester during the reaction, and quickly leave the polyester during or after the reaction. In other words, this solvent is 140 to 2 in which esterification or transesterification reaction is active.
It is preferable that 15 wt% or less of the solvent remains in the polyester solution at 50 ° C. Further, it is preferable that this solvent can be completely distilled off from the polyester at a maximum reaction temperature of 350 ° C. or lower, and it is more preferable that it can be distilled off at 260 ° C. or lower at which the reaction is almost completed.

A preferred solvent that can be used in the above methods 1 and 2 is dimethyl sulfoxide (hereinafter referred to as DMSO).
Abbreviated), N, N-dimethylacetamide (hereinafter, DM
AC), N, N-dimethylformamide (hereinafter,
DMF), N-methyl-2-pyrrolidone (hereinafter,
(Abbreviated as NMP), tetrahydrofuran, toluene, xylene, ethyl acetate, butyl acetate are preferable. Among them, the ones that satisfy the methods 1 and 2 more preferably are DMSO and D.
MAC and DMF. Further, toluene and xylene are used for the purpose of azeotropically removing the by-products of the esterification or transesterification reaction of the polyester prepolymer.

Since the polyester prepolymer solution using the solvent of the present invention preferably has a high concentration, it can be dissolved at a high temperature. The prepolymer concentration range in the present invention is 3 to 50% by weight, preferably 10 to 35% by weight in order to obtain a good viscosity in the work of pouring into a mold and a plate having releasability.

A method for distilling the solvent from the prepolymer solution will be described. In the method 1 of the present invention, the polyester prepolymer solution is cast into a target mold or cast on a plate or a metal foil having releasability, and before esterification or transesterification reaction becomes active. The solvent is removed at a temperature of 160 ° C or lower, preferably 120 ° C or lower. The ratio of the residual solvent to the total of the prepolymer and the residual solvent is 30 wt% or less, preferably 1
The solvent is removed until it becomes 0 wt% or less. If the ratio of the residual solvent exceeds the upper limit, fluidity may remain and the desired shape cannot be maintained. Then, the prepolymer from which the solvent has been distilled off is heated again and undergoes esterification or transesterification to form a polyester having a regular network structure. In Method 2, the solvent is distilled off at the same time as the polymerization of the polyester in the solution proceeds.

Next, the synthesis of a polyester having a regular network structure will be described. In the method 1, the prepolymer from which the solvent was distilled off was heated at a temperature of 120 to 3 in an inert atmosphere.
The reaction is carried out at 50 ° C, preferably 130 to 300 ° C, more preferably 140 to 260 ° C for 1 to 18 hours. If the temperature is lower than the lower limit temperature, the reaction does not proceed. If the temperature is higher than the upper limit temperature, thermal decomposition of the polyester oligomer and the raw material occurs.
In addition, in the final stage of the reaction in which the solvent remaining in the polyester is extremely small, it is preferable to use a combination of vacuum drying at 50 kPa or less and far-infrared firing for the purpose of completely removing the solvent and promoting the reaction. In addition, the combined use of hot air in the method 2 described below is also effective. In method 2, 50 to 350 from the solution
℃, preferably 60 to 300 ℃, more preferably 70 ~
Polymerization is carried out directly at 260 ° C., and simultaneous solvent removal is also extremely important. When the temperature is lower than the lower limit temperature, the solvent is hard to be distilled off, and when the temperature is higher than the upper limit temperature, the polyester oligomer and the raw material are thermally decomposed. In method 2, in addition to this temperature, it is preferable to consider hot-air drying in a range of less than 20 m / sec, preferably less than 12 m / sec. That is,
In the solution state at the initial stage of drying, the wind speed is preferably 0 or as low as possible, and when drying progresses to form a film on the surface, a constant wind speed has an effect on the drying and the reaction. However, even if the upper limit of the hot air velocity of the present invention is exceeded, a large drying effect cannot be expected. Further, it is not preferable because the dried film surface may be wavy. At the end of the reaction where the drying has progressed, the vacuum drying and far-infrared ray of the above-mentioned method 1 are also effective.

This reaction may be carried out without a catalyst, but the catalyst for the polyester prepolymer may be used as it is or a new catalyst may be added. In the present production method, a heat stabilizer or the like may be added for the purpose of suppressing the thermal decomposition of the polyester and the raw material.

The completion of the reaction can be estimated from the ratio of the amount of the distillate to the theoretical amount of the reaction by-products and the rate of change of the weight loss by a thermobalance below the decomposition temperature. However, in any case, the influence of the solvent cannot be ignored, and it takes time to prepare and measure the analysis, so that it is not suitable as a method for knowing the end point. In addition, there is a method using an NMR intensity curve for polyester in which the solvent effect can be neglected, but the analysis operation and analysis are difficult, complicated, and impractical.

On the other hand, the end of the reaction in the present invention can be easily known in a short time by using an infrared absorption spectrum. That is, the polyester having a regular mesh structure in the reaction step, -OH groups and -CH ₃ group, -
Having a CH ₂ — group, a> CH— group or a> C <group,
3400-3500cm ^-1 (peak A) and 2930-2
It can be attributed to the absorption peak appearing at 980 cm ^-1 (peak B). Here, the intensity of the peak B is unchanged, whereas the intensity of the peak A decreases as the reaction proceeds.
Now, the relative intensity ratio [A] / [B] can be approximated as shown in formula (2) when considering a mathematical model of one molecule of polyhydric alcohol and three molecules of dicarboxylic acid. [A] / [B] = (6-X) / (Z * m + L) Formula (2) Here, X is the average number of functional groups actually reacted in three molecules of dicarboxylic acid, and 0 ≦ X ≦ 6. Is. Z is the average value of the number of bonds in one molecule of polyhydric alcohol, and for example, when trivalent alcohol is used, Z = 3. m is —CH ₃ group, —CH ₂ — group,> C in each dicarboxylic acid molecule.
It is an average value per molecule obtained by adding 2 to the total number of H-groups and> C <groups. For example, in the case of 1 mol of adipic acid and 1 mol of undecanedioic acid, m = 8.5. L is a value obtained by subtracting Z from the total number of —CH ₃ group, —CH ₂ — group,> CH— group and> C <group in one molecule of polyhydric alcohol. For example, when the polyhydric alcohol is glycerol, In the case of L = 0, 2 mol of glycerol and 1 mol of trimethylolpropane, L = 1. Thus, the reaction rate Y (%) of the polyester having a regular network structure pays attention to dicarboxylic acids,
It is shown by equation (3). Y = X / 6 * 100 Formula (3) From the relationship between the reaction rate Y and the reaction time, the reaction termination time and the reaction rate at that time are determined.

In the polyester having a regular network structure according to the present invention, the reaction rate is preferably 66% or more, more preferably 75% or more. If the value is below the lower limit, the reaction is insufficient and a satisfactory network structure is unlikely to be obtained, and sufficient acid resistance and alkali resistance are not exhibited. Here, when the reaction rate is 66% or more, in the case of trifunctional, two or more bond hands are involved in the reaction on average. Considering the high reaction rate of hydroxyl groups of these trifunctional alcohols and the raw materials to be charged, a two-dimensional and partly three-dimensional network structure in which the trihydric alcohol exists again before the dicarboxylic acid is bonded to the trifunctional alcohol I can guess that. In particular, when the reaction rate is 75% or more, the three-dimensional network structure is considerably generated, and the object of the present invention is sufficiently achieved.

The polyester molded product having a regular network structure of the present invention can be obtained by removing a mold or a plate having releasability. In the method 1, in order to produce a polyester film, the surface of the dried prepolymer film is peeled off without pressing the solvent to the finger, and the film is left unstretched at a high temperature or uniaxially or biaxially. A high elasticity film can be prepared after stretching. As another case, the metal foil and the polyester resin layer of the present invention may adhere and do not peel off, but even if the metal foil is easily melted with an acid or the like, the film of the present invention having appropriate strength, texture, transparency, etc. Obtainable.

The present invention is a biodegradable polyester having a regular network structure, which comprises a polyhydric alcohol containing a trihydric alcohol as a main component and an aliphatic dicarboxylic acid as constituent components. A combination of a tetravalent alcohol exemplified by mesoerythritol, pentaerythritol and the like and an aliphatic dicarboxylic acid, tartaric acid,
Malic acid, 2,2-bis (hydroxymethyl) propionic acid, Mucic Acid, a mixture of a polyhydric hydroxycarboxylic acid and an aliphatic dicarboxylic acid exemplified by citric acid and an aliphatic diol, and a polyfunctional compound A mixture of a mixture with an aliphatic dicarboxylic acid and an aliphatic diol, a mixture of a mixture of an aromatic compound-containing polyfunctional compound and an aromatic compound-containing aliphatic dicarboxylic acid, or a polyfunctional (or polyfunctional) Polyesters comprising a combination of (alcohol) and a molecular-controlled polyester polyacid or polyester polyol containing an aromatic compound also have good biodegradability.

The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

BEST MODE FOR CARRYING OUT THE INVENTION

EXAMPLES The physical properties of polyesters having a regular network structure described in Examples and Comparative Examples in the text were measured as follows. [Measurement of physical properties] Infrared absorption measurement The infrared absorption intensity of the film of the present invention was measured using a model IRA-1 type infrared spectrometer manufactured by JASCO Corporation, and the product of the present invention was measured according to (Equation 2) and (Equation 3). Was determined as shown in Table 1. 2. X-ray measurement Using a model ADG-301 type wide-angle X-ray diffractometer manufactured by Toshiba Corp., a film of the present invention (3 mm * 8 mm * 0.1 mm) by CuKα rays passed through a Ni filter was used. The diffraction intensity was measured. The results are shown in FIG. 3. Water absorption measurement The film of the present invention (30 mm * 30 mm) in water at 30 ° C.
* 0.1 mm) for 24 hours, water on the surface was sufficiently removed, and the rate of increase in mass relative to the film before immersion was determined. The measurement results of the rate of increase due to water absorption are shown in Table 1 as follows. ◯: Increase is less than 1.5%, almost no water absorption, Δ:
If the amount of increase is 1.5% or more and less than 3.0%, the water absorption is small,
X: The amount of increase is 3.0% or more, and the water absorption is large. 4. Chemical resistance test 4-1. Acid Resistance Test The film of the present invention (30 mm * 30 mm * 0.1 mm) was immersed in a 15 wt% HCl aqueous solution at 30 ° C. for 6 hours and then washed with water to sufficiently remove water adhering to the surface, and the rate of decrease in mass relative to the film before immersion. I asked. The measurement results are shown in Table 1 as follows. ◎: Reduction rate is less than 1.5% and there is almost no mass change. ○: Reduction rate is 1.5% or more and 10
%: Less than 10%, Δ: reduction rate 10% or more 20
%: Less than 20%, x: greater than 20%, large decrease in mass. 4-2. Alkali resistance test A film of the present invention (30 mm * 30 mm * 0.1 mm) is immersed in a 5 wt% NaOH aqueous solution at 40 ° C. for 6 hours and then washed with water to sufficiently remove water adhering to the surface, and the rate of decrease in mass relative to the film before immersion. I asked. The measurement results are shown in Table 1 as follows. ：: Reduction rate is less than 3% and there is almost no change in mass; ：: Reduction rate is slightly reduced when the reduction rate is 3% or more and less than 10%; Δ: Weight is reduced when the reduction rate is 10% or more and less than 20%; X: 20 % Or more, the mass loss is large. 4-3. Organic solvent resistance test Toluene, acetone, DMF and the film of the present invention (30
(mm * 30 mm * 0.1 mm) was immersed for 24 hours and then washed with water to sufficiently remove water adhering to the surface, and the state of the film before immersion was compared with the surface. ：: no change, Δ: slightly melted, ×: melted. 5. Biodegradability test 1/15 mol phosphate buffer (PH = 7.2) 100
lysopass delemar lipase (Seikagaku Corporation)
40 mg of product, fine powder grade) and 4 sheets of film (30 mm * 30 mm * 0.1 mm) of the present invention
It was left at 7 ° C. After 3 and 24 hours have passed, the film is taken out and washed with water to sufficiently remove water adhering to the surface,
It was dried at 80 ° C. under a reduced pressure of 1.5 kPa for 24 hours, and the mass reduction rate with respect to the film before immersion in the culture solution was determined. The measurement results after culturing for each time are shown in Table 1 as follows. ◎: Reduction rate is 20% or more and biodegradability is extremely large, ○: Reduction rate is 1
0% or more and less than 20% biodegradable, Δ: decrease rate of 5% or more and less than 10%, some biodegradable, x: less than 5%, almost no biodegradable. 6. Thermal Mechanical Analysis (TMA) Using a Model TMA-100 thermomechanical property analyzer manufactured by Seiko Denshi Kogyo Co., Ltd., under a nitrogen gas stream, a heating rate 2
Under the conditions of 0 ° C./min and a load of 10 kg / cm ² , the softening point of the film of the present invention (3 mm * 20 mm * 0.1 mm) was measured. Table 2 shows the softening points of Examples 1 to 7 and Comparative Examples 1 and 2. 7. Measurement of residual solvent ratio Using a model TGA-100 thermobalance analyzer (TG) manufactured by Seiko Denshi Kogyo Co., Ltd., the temperature of the reaction intermediate product of the present invention such as the prepolymer measured accurately was raised under a nitrogen gas stream. The weight change from room temperature to 260 ° C. was measured at a rate of 5 ° C./min to determine the thermogravimetric reduction rate, which was taken as the residual solvent rate. (Example 1) 36.8 g (0.4 mol) of glycerol and 87.6 g (0.6 mol) of adipic acid were charged into a reaction vessel under a nitrogen gas atmosphere and reacted at 200 ° C for 50 minutes to obtain a polyester prepolymer. This was dissolved in DMF to prepare a 20 wt% solution. This solution was cast on an aluminum foil and heated at 80 ° C. to remove the solvent. Next, in a hot air circulation dryer, under a nitrogen gas stream at 150 ° C. for 0.5 hours,
Next, the drying and reaction were allowed to proceed at 230 ° C. for 1 hour, and the exhaust port was half-opened or less at the same temperature and the same atmosphere, 10 m /
The reaction and drying were promoted by supplying circulating hot air for 2 hours for 4 hours. After completion of the reaction and drying, aluminum is removed with a 10% HCl aqueous solution, washed sufficiently with water, and dried at 40 ° C. under a reduced pressure of 1.5 kPa for 24 hours to obtain a transparent and appropriate film having a thickness of 0.1 mm. Got This film was stored in a desiccator. The reaction rate of the polyester film measured by infrared absorption was 78%. Table 1 shows the test results of biodegradability, water absorption, and chemical resistance. (Example 2) 9.2 g (0.1 mol) of glycerol and 24 g (0.15 mol) of pimelic acid were placed in a reaction vessel in a nitrogen gas atmosphere and reacted at 200 ° C for 40 minutes to obtain a polyester prepolymer. 20 in DMF
wt% solution. This solution was cast on an aluminum foil and heated at 80 ° C. to remove the solvent. Next, in a hot-air circulation dryer, the drying and reaction were allowed to proceed at 150 ° C. for 0.5 hours under nitrogen gas flow and then at 230 ° C. for 1 hour, and the exhaust port was opened halfway or less at the same temperature and the same atmosphere. Circulation hot air of 10 m / sec was given for 3 hours to proceed the reaction and drying. After completion of the reaction and drying, aluminum is removed with a 10% HCl aqueous solution, washed sufficiently with water, and dried at 40 ° C. under a reduced pressure of 1.5 kPa for 24 hours to obtain a transparent and appropriate film having a thickness of 0.1 mm. Got This film was stored in a desiccator. The reaction rate of the polyester film measured by infrared absorption was 89%. Table 1 shows the test results of biodegradability, water absorption, and chemical resistance. (Example 3) 9.2 g (0.1 mol) of glycerol and 26.1 g (0.15 mol) of suberic acid were charged in a reaction vessel under a nitrogen gas atmosphere and reacted at 200 ° C for 70 minutes to obtain a polyester prepolymer. This was dissolved in DMF to prepare a 20 wt% solution. This solution was cast on an aluminum foil and heated at 80 ° C. to remove the solvent. Next, in a hot air circulation dryer, under a nitrogen gas stream at 150 ° C. for 0.5 hours,
Drying and reaction were allowed to proceed at 230 ° C. for 1 hour, the exhaust port was opened halfway or less under the same temperature and same atmosphere, and circulating hot air of 10 m / sec was given for 3 hours to proceed the reaction and drying. After completion of the reaction and drying, aluminum is removed with a 10% HCl aqueous solution, washed sufficiently with water, and dried at 40 ° C. under a reduced pressure of 1.5 kPa for 24 hours to obtain a transparent and appropriate film having a thickness of 0.1 mm. Got This film was stored in a desiccator. The reaction rate of the polyester film measured by infrared absorption was 93%. Table 1 shows the test results of biodegradability, water absorption, and chemical resistance. (Example 4) 36.8 g (0.4 mol) of glycerol and 112.8 g (0.6 mol) of azelaic acid were placed in a reaction vessel under a nitrogen gas atmosphere and reacted at 200 ° C. for 80 minutes to obtain a polyester prepolymer. This was dissolved in DMF to prepare a 20 wt% solution. This solution was cast on an aluminum foil and heated at 80 ° C. to remove the solvent. Next, in a hot air circulation dryer, the drying and reaction were allowed to proceed at 150 ° C. for 0.5 hours and 230 ° C. for 1 hour under a nitrogen gas stream, and the exhaust port was opened halfway or less at the same temperature and the same atmosphere for 10 m. Circulation hot air of 1 second was given for 3 hours to proceed the reaction and drying. After completion of the reaction and drying, aluminum is removed with a 10% HCl aqueous solution, washed sufficiently with water, and dried at 40 ° C. under a reduced pressure of 1.5 kPa for 24 hours to obtain a transparent and appropriate film having a thickness of 0.1 mm. Got This film was stored in a desiccator. The reaction rate of the polyester film measured by infrared absorption was 95%. Biodegradable,
Table 1 shows the test results of water absorption and chemical resistance. (Example 5) 36.8 g (0.4 mol) of glycerol and 121.281 g (0.6 mol) of sebacic acid were placed in a reaction vessel under a nitrogen gas atmosphere and reacted at 200 ° C for 140 minutes to obtain a polyester prepolymer. This was dissolved in DMF to prepare a 20 wt% solution. This solution was cast on an aluminum foil and heated at 80 ° C. to remove the solvent. Next, in a hot air circulation dryer, the drying and reaction proceeded under a nitrogen gas stream at 150 ° C. for 0.5 hours and at 230 ° C. for 1 hour, and the exhaust port was opened halfway or less at the same temperature and the same atmosphere.
Reaction and drying were promoted by supplying circulating hot air of 10 m / sec for 3 hours. After completion of the reaction and drying, the aluminum was
After removing with Cl aqueous solution and washing thoroughly with water, at 40 ° C for 1.5
By drying under reduced pressure of kPa for 24 hours, a transparent film having a proper strength and a thickness of 0.1 mm was obtained. This film was stored in a desiccator. The conversion of the polyester film determined by infrared absorption was 94%.
Table 1 shows the test results of biodegradability, water absorption, and chemical resistance. (Example 6) 4.6 g (0.4 mol) of glycerol and 138 g (0.6 mol) of dodecanedioic acid were charged into a reaction vessel under a nitrogen gas atmosphere, and the mixture was heated at 200 ° C for 40 minutes and then at 250 ° C for 60 minutes.
A polyester prepolymer was obtained by reacting for minutes, and this was dissolved in DMF to prepare a 20 wt% solution. This solution was cast on an aluminum foil and heated at 80 ° C. to remove the solvent. Next, in a hot air circulation dryer, under a nitrogen gas stream, 1
The drying and reaction proceeded at 50 ° C for 0.5 hours and 230 ° C for 1 hour, and the exhaust port was opened halfway or less at the same temperature and the same atmosphere, and 10 m / sec of circulating hot air was applied for 3 hours to carry out the reaction and drying. I advanced. After completion of the reaction and drying,
Removed with 0% HCl aqueous solution and washed thoroughly with water
By drying under a reduced pressure of 1.5 kPa for 24 hours, a 0.1 mm thick film having a transparent and appropriate strength was obtained. This film was stored in a desiccator. The reaction rate of the polyester film measured by infrared absorption was 97%. Table 1 shows the test results of biodegradability, water absorption, and chemical resistance. (Example 7) 4.6 g (0.05 mol) of glycerol and 20.4 g (0.075 mol) of pentadecanedioic acid were charged into a reaction vessel under a nitrogen gas atmosphere, and the mixture was kept at 200 ° C. for 40 minutes for 2 minutes.
The reaction was carried out at 50 ° C. for 90 minutes to obtain a polyester prepolymer, which was dissolved in DMF to prepare a 20 wt% solution. This solution was cast on an aluminum foil and heated at 80 ° C. to remove the solvent. Next, in a hot air circulation dryer, the drying and reaction were allowed to proceed at 150 ° C. for 0.5 hours and 230 ° C. for 1 hour under a nitrogen gas stream, and the exhaust port was opened halfway or less at the same temperature and the same atmosphere for 10 m. Circulation hot air of 1 second was given for 3 hours to proceed the reaction and drying. After the reaction and drying are completed, aluminum is removed with a 10% HCl aqueous solution, washed sufficiently with water, and then dried at 40 ° C. under a reduced pressure of 1.5 kPa for 24 hours to obtain a transparent and appropriate film having a thickness of 0.1 mm. Got This film was stored in a desiccator. The reaction rate of the polyester film measured by infrared absorption was 86%. Table 1 shows the test results of biodegradability, water absorption, and chemical resistance. (Example 8) 36.8 g (0.4 mol) of glycerol,
Dodecanedioic acid 96.6 g (0.42 mol) and succinic acid 2
1.2 g (0.18 mol) was charged into a reaction vessel in a nitrogen gas atmosphere and reacted at 200 ° C. for 90 minutes and at 250 ° C. for 1 hour to obtain a polyester prepolymer, which was DMSO.
Into a 20 wt% solution. This solution was cast on an aluminum foil and heated at 80 ° C. to remove the solvent. Next, in a hot air circulation dryer, the drying and reaction proceeded under a nitrogen gas stream at 150 ° C. for 0.5 hours and at 230 ° C. for 1 hour, and the exhaust port was opened halfway or less at the same temperature and the same atmosphere.
Circulation hot air of 10 m / sec was given for 4 hours to proceed the reaction and drying. After completion of the reaction and drying, the aluminum was
After removing with Cl aqueous solution and washing thoroughly with water, at 40 ° C for 1.5
By drying under reduced pressure of kPa for 24 hours, a transparent film having a proper strength and a thickness of 0.1 mm was obtained. This film was stored in a desiccator. The reaction rate of the polyester film measured by infrared absorption was 88%.
Table 1 shows the test results of biodegradability, water absorption, and chemical resistance. (Example 9) 7.36 g (0.08 mol) of glycerol, 2.68 g (0.02 mol) of trimethylolpropane, 28.89 g (0.143 mol) of sebacic acid and 2 g (0.007 mol) of hexadecanedioic acid. Was charged into a reaction vessel under a nitrogen gas atmosphere and reacted at 200 ° C. for 90 minutes and at 250 ° C. for 1 hour to obtain a polyester prepolymer, which was dissolved in NMP at 80 ° C. to prepare a 25 wt% solution.
This solution was cast on an aluminum foil and dried and reacted at 120 ° C. for 1 hour and at 230 ° C. for 1 hour under a nitrogen gas stream in a hot air circulation dryer with the exhaust port fully opened. Under an atmosphere, the exhaust port was opened halfway or less and circulating hot air of 10 m / sec was given for 4 hours to proceed the reaction and drying. After completion of the reaction and drying, aluminum is removed with a 10% HCl aqueous solution, washed sufficiently with water, and dried at 40 ° C. under a reduced pressure of 1.5 kPa for 24 hours to obtain a transparent and appropriate film having a thickness of 0.1 mm. Got This film was stored in a desiccator. The reaction rate of the polyester film measured by infrared absorption was 86%. Biodegradable,
Table 1 shows the test results of water absorption and chemical resistance. (Example 10) 6.44 g (0.07 mol) of glycerol, 3.6 g (0.03 mol) of trimethylolethane, 20.88 g (0.12 mol) of suberic acid and 5.16 g (0.10 mol) of cyclohexanedicarboxylic acid. (03 mol) was charged into a reaction vessel in a nitrogen gas atmosphere and reacted at 200 ° C. for 180 minutes to obtain a polyester prepolymer, which was dissolved in NMP at 80 ° C. to obtain a 24 wt% solution. This solution was cast on an aluminum foil and dried and reacted at 140 ° C for 0.5 hours and 230 ° C for 1 hour under a nitrogen gas stream in a hot air circulation dryer with the exhaust port fully opened, and then at the same temperature. In the same atmosphere, the exhaust port was opened halfway or less and the circulating hot air of 10 m / sec was given for 3 hours to proceed the reaction and drying. After completion of the reaction and drying, aluminum is removed with a 10% HCl aqueous solution, washed sufficiently with water, and dried at 40 ° C. under a reduced pressure of 1.5 kPa for 24 hours to obtain a transparent and appropriate film having a thickness of 0.1 mm. Got This film was stored in a desiccator. The conversion of the polyester film determined by infrared absorption was 83%. Biodegradable,
Table 1 shows the test results of water absorption and chemical resistance. Further, a comparative example is shown in order to further clarify the present invention. (Comparative Example 1) 36.8 g (0.4 mol) of glycerol and 70.8 g (0.6 mol) of succinic acid were placed in a reaction vessel under a nitrogen gas atmosphere and reacted at 200 ° C. for 100 minutes to obtain a polyester prepolymer. , 20w dissolved in DMF
It was a t% solution. This solution was cast on an aluminum foil and heated at 80 ° C. to remove the solvent. Next, in a hot air circulation dryer, under a nitrogen gas stream at 150 ° C. for 0.5 hour, 230
The drying and the reaction were allowed to proceed for 1 hour at 0 ° C., the exhaust port was opened halfway or less under the same temperature and the same atmosphere, and 10 m / sec of circulating hot air was applied for 4 hours to proceed the reaction and the drying. After completion of the reaction and drying, aluminum was removed with a 10% aqueous solution of HCl, and after sufficient washing with water, 2 ° C. under a reduced pressure of 1.5 kPa at 40 ° C.
By drying for 4 hours, a transparent film having a suitable strength and a thickness of 0.1 mm was obtained. This film was stored in a desiccator. The reaction rate of the polyester film measured by infrared absorption was 51%. Table 1 shows the test results of biodegradability, water absorption, and chemical resistance. (Comparative Example 2) 4.6 g (0.05 mol) of glycerol and 21.5 g (0.075 mol) of hexadecanedioic acid were charged into a reaction container under a nitrogen gas atmosphere, and the mixture was kept at 200 ° C. for 40 minutes for 2 minutes.
The reaction was carried out at 50 ° C. for 90 minutes to obtain a polyester prepolymer, which was dissolved in DMF to prepare a 20 wt% solution. This solution was cast on an aluminum foil and heated at 80 ° C. to remove the solvent. Next, in a hot air circulation dryer, the drying and reaction were allowed to proceed at 150 ° C. for 0.5 hours and 230 ° C. for 1 hour under a nitrogen gas stream, and the exhaust port was opened halfway or less at the same temperature and the same atmosphere for 10 m. Circulation hot air of 1 second was given for 3 hours to proceed the reaction and drying. After completion of the reaction and drying, the aluminum was removed with a 10% HCl aqueous solution, and after thoroughly washing with water, 4
By drying at 0 ° C. under a reduced pressure of 1.5 kPa for 24 hours, a transparent film having a proper strength and a thickness of 0.1 mm was obtained. This film was stored in a desiccator. The reaction rate of the polyester film measured by infrared absorption is 88.
%Met. Table 1 shows the test results of biodegradability, water absorption, and chemical resistance. (Comparative Example 3) Glycerol 36.8 g (0.4 mol),
Suberic acid 10.44 g (0.06 mol) and malonic acid 5
6.16 g (0.54 mol) was charged into a reaction vessel in a nitrogen gas atmosphere and reacted at 200 ° C. for 120 minutes to obtain a polyester prepolymer, which was dissolved in DMF to prepare a 20 wt% solution. This solution is cast on an aluminum foil at 80 ° C.
The solvent was removed by heating at. Next, in a hot air circulation dryer, under nitrogen gas flow, at 150 ° C for 0.5 hour, at 230 ° C for 1 hour.
The drying and reaction were allowed to proceed for a period of time, and the exhaust port was opened halfway or less under the same temperature and atmosphere, and 10 m / sec of circulating hot air was applied for 3 hours to allow the reaction and the drying to proceed. After the completion of the reaction and drying, aluminum was removed with a 10% HCl aqueous solution, washed sufficiently with water, and then dried at 40 ° C. under a reduced pressure of 1.5 kPa for 24 hours to obtain a transparent and appropriate thickness of 0.1.
A 1 mm film was obtained. This film was stored in a desiccator. The reaction rate of the polyester film measured by infrared absorption was 56%. Table 1 shows the test results of biodegradability, water absorption, and chemical resistance. (Comparative Example 4) 1,6-hexanediol 17.7 g
(0.15 mol) and 1,3,5-pentanetriacid 20.4
g (0.1 mol) was charged into a reaction vessel under a nitrogen gas atmosphere and reacted at 200 ° C. for 50 minutes to obtain a polyester prepolymer, which was dissolved in NMP at 80 ° C. to give 23 wt%
The solution was used. This solution was cast on an aluminum foil and placed under a nitrogen gas stream in a hot air circulation dryer with the exhaust port fully opened.
The drying and reaction proceeded at 20 ° C. for 1.5 hours and 230 ° C. for 1 hour, the exhaust port was opened halfway or less at the same temperature and atmosphere, and 10 m / sec circulating hot air was applied for 4 hours to carry out the reaction and drying. I advanced. After completion of the reaction and drying,
It was removed with a 0% HCl aqueous solution, washed sufficiently with water, and then dried at 40 ° C. under a reduced pressure of 1.5 kPa for 24 hours to obtain a transparent film having an appropriate strength and a thickness of 0.1 mm. This film was stored in a desiccator. The reaction rate of the polyester film measured by infrared absorption was 77%. Table 1 shows the test results of biodegradability, water absorption, and chemical resistance. (Comparative Example 5) 20 g (0.2 mol) of succinic anhydride, 43.8 g (0.3 mol) of adipic acid, and 72 g (0.8 mol) of 1,4-butanediol were charged into a reaction vessel under a nitrogen gas atmosphere. The resulting water and excess glycol component were distilled off at 200 ° C. for 3 hours to obtain a polyester oligomer. To this, 0.27 g of tributoxy antimony was added and reacted at 220 ° C. under a reduced pressure of 66 Pa for 2 hours and at 240 ° C. under a reduced pressure of 66 Pa for 1 hour to obtain a viscous liquid, which was then placed on an aluminum foil. Then, the mixture was cast into a plate and cooled to room temperature. Aluminum was removed with a 10% aqueous solution of HCl, washed sufficiently with water, and then dried at 40 ° C. under a reduced pressure of 1.5 kPa for 24 hours to obtain a 0.1 mm film. The film had a slightly dissolved surface appearance. Table 1 shows the test results of biodegradability, water absorption and chemical resistance of the film.

The polyester of the present invention is a compound in which a polyhydric alcohol containing a trihydric alcohol as a main component and an aliphatic dicarboxylic acid containing a specific aliphatic dicarboxylic acid are chemically bonded alternately. As shown in the examples, the hydroxyl groups of these polyhydric alcohols and the carboxyl groups of the carboxylic acids were reacted in equal amounts, and the results of infrared absorption spectrum measurement showed that the reaction rate of the present invention was 78 to 97%. It was Focusing on the three hydroxyl groups (bonds) of glycerin, this reaction rate was 2.3 to 2.
Nine bonds are involved in the reaction. That is, the polyester of the present invention forms a network structure in which glycerin and the glycerin closest to the glycerin are connected by 2.3 to 2.9 bonds. In addition, the X-ray contact strength curve of the molded product of the present invention has a black angle of 2θ = 20 deg. A prominent single peak was shown around the vicinity. This indicates a regularity that the atoms in the polyester of the present invention form a fixed array structure, and the atoms having an array at an interval of about 4 to 5 angstroms are the largest. Furthermore, the sharpness of the remarkable single peak means that the atomic group showing the regularity is large, that is, the regularity in the polyester of the present invention is high. As described above, the product of the present invention is determined to be a polyester having a regular network structure from the raw materials, the conversion, and the X-ray diffraction intensity.

Usually, the terminal group quantification method, the solution viscosity method, the osmotic pressure method, the gel permeation chromatography method and the melt viscosity method, which are used as molecular weight measurement methods, are measured by
Polymer solubility and meltability are required. However,
Since the final compound of the present invention is a polyester having a regular network structure, it is acid-resistant, alkali-resistant and solvent-resistant, and hardly exhibits hot-meltability. Therefore, a method for determining the molecular weight of the polyester of the present invention. Is currently not found.

Usually, the titration analysis after hydrolysis with an alkali used for quantifying the composition in polyester cannot be applied because the product of the present invention is extremely excellent in alkali resistance. By finding an appropriate solvent, the composition in the polyester of the present invention can be quantified by NMR measurement and IR measurement, but it is impossible to find an appropriate solvent, and a trace amount in the polyester in the production stage of the product of the present invention. In reality, it is difficult to obtain an accurate NMR curve due to the influence of the residual solvent.

The polyester of the present invention synthesized from a trihydric alcohol and a dicarboxylic acid having a specific length has excellent chemical resistance and shows rapid biodegradability by lipase. Particularly when the linear dicarboxylic acid has 8 to 12 carbon atoms, 2
After 4 hours, the film was completely decomposed and no film shape was observed. On the other hand, the decomposition rate of the linear polyester of Comparative Example 5 is very slow. Further, the polyester composed of polycarboxylic acid and diol described in Comparative Example 4 shows almost no biodegradability.

In the present invention, the reason why the excellent performance is exhibited is not always clear, but it is presumed as follows. A polyester composed of a trihydric alcohol and a dicarboxylic acid having a predetermined length or more forms a void having a size that allows lipase to enter, and the invaded lipase is attacked from the carboxyl group side of the ester bond and decomposes. However, in the case of a longer dicarboxylic acid, the lipase penetrates by increasing the pore size of the polyester, but the number of ester bonds per unit volume decreases. Also, at this time,
As can be seen from Table 2, the softening point increases, the molecular motion of the polyester decreases, and lipase invasion is suppressed. As described above, when the dicarboxylic acid having a certain length is 65 mol% or more based on the total dicarboxylic acids, the polyester biodegrades to break the three-dimensional structure into a two-dimensional or one-dimensional structure, which is successively biodegraded by lipase. Can be generated. The polyester of Comparative Example 4 has a network structure composed of a polycarboxylic acid and a diol, but the direction of the ester bond is opposite to the center of the network. In the case of Comparative Example 4, it is considered that the lipase that has penetrated into the polyester attacks the ester bond from the hydroxyl group side, which is different from the decomposition mechanism assumed in the present invention. In other words, it is presumed that there was no void on the carboxyl group side for lipase.
The chain polyester of Comparative Example 5 has a high degree of freedom, and it is sufficiently conceivable to wrap the ester bond at a site other than this bond portion. On the other hand, in the polyester of the present invention, the bonding group is almost fixed. If the lipase comes close to the linear polyester and the polyester of the present invention, it can be speculated that the latter will biodegrade quickly. As presumed above, the reason why the product of the present invention is superior is considered to be that it has a specific chemical structure as compared with other polyesters.

[0035]

The polyester obtained according to the present invention is:
It is a biodegradable polyester that exhibits excellent alkali resistance, acid resistance, water resistance, and organic solvent resistance and that can be disintegrated by lipase. Since the softening point of the polyester of the present invention is around room temperature, it can be deformed into a molded article such as a film or sheet excellent in the above-mentioned properties. It is also expected to be used for adhesive materials, has low environmental pollution, and has great industrial significance.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Brief description of drawings]

1 is an X-ray diffraction intensity curve for the polyesters obtained in the examples.

Claims (4)

[Claims] 1. A polyester comprising a polyhydric alcohol containing a trihydric alcohol as a main component and an aliphatic dicarboxylic acid as a constituent component, wherein the aliphatic dicarboxylic acid is a straight chain represented by the formula (1). Aliphatic dicarboxylic acids containing at least 65 mol% of one or more compounds selected from among aliphatic dicarboxylic acids or acid anhydrides or acid esters thereof (collectively referred to as linear aliphatic dicarboxylic acids) A biodegradable polyester having a regular network structure. Embedded image Formula (1) (where n = 6 to 15) 2. The linear aliphatic dicarboxylic acid is a compound selected from linear aliphatic dicarboxylic acids having n in the formula (1) of 8 to 12. A biodegradable polyester having a regular network structure according to 1. 3. A polyhydric alcohol containing a trihydric alcohol as a main component and an aliphatic dicarboxylic acid having 6 to 15 carbon atoms in an inert gas atmosphere at 120 to 270 ° C. for 30 to 240.
Polyester prepolymer obtained by melt polymerization for minutes,
After being dissolved in a solvent to form a solution, it is poured into a mold (a) or cast on a mold releasing agent, and the solvent is distilled off.
A solid phase polymerization reaction at ˜350 ° C., or injection into a mold (b) or casting into a mold, and polymerization is carried out while distilling off the solvent at 50 to 350 ° C. A method for producing a biodegradable polyester molded article having the same. 4. An aliphatic dicarboxylic acid represented by the formula (1)
The method for producing a biodegradable polyester molded product having a regular network structure according to claim 3, which comprises a linear aliphatic dicarboxylic acid represented by the formula (4).