JPWO2010001898A1 - Method for producing hyperbranched polyester, method for producing polyurethane, polyurethane - Google Patents

Abstract

Provided is a method for producing a multibranched polyester that makes it possible to easily produce a multibranched polyester at a low cost. A multibranched polyester is produced by reacting glycidol with a cyclic acid anhydride to synthesize a multibranched polyester.

Description

  The present invention relates to a method for producing a multibranched polyester excellent in biodegradability, a method for producing a polyurethane excellent in biodegradability using the multibranched polyester, and a polyurethane excellent in biodegradability.

Plastic products containing polyurethane do not corrode and therefore exist for a long time and have a negative impact on the environment. For example, agricultural polymer films are used to protect seedlings from wind and rain, but a great deal of effort is required to recover these polymer films after growth.
Moreover, since this polymer film is difficult to reuse, it is incinerated or dumped illegally, which is not only an environmental problem but also a social problem.

If attention is paid to biodegradable plastic, it will be decomposed as the crop grows, so there is no need to collect it.
Therefore, among polymers, agricultural polymers are created by creating new materials containing ester groups that have physical properties excellent in oil resistance, mechanical and thermal properties, and have biodegradability and hydrolyzability. It is considered that the problem of film recovery can be improved (see, for example, Patent Document 1).
Currently, biodegradable copolymer production methods, biodegradation methods and applications to fibers, films, planting pots, agricultural multi-films have been proposed, and degradation of polycaprolactone and polytetramethylene adipate has also been reported. .

However, it is well known that a polymer (ester) containing an ester group is rigid and poor in flexibility when used as a film because it has crystallinity.
Therefore, it is considered that by introducing a multi-branched skeleton, an amorphous polyester is obtained, and a flexible polyester is obtained. If a multibranched polyester having a branched structure is synthesized and used, a flexible polymer material excellent in hydrolyzability and biodegradability can be obtained.

  As the hyperbranched polyester, for example, Boltorn (registered trademark) manufactured by Perstorp having a structure branched in a dendritic shape has been proposed.

In order to synthesize a multi-branched polyester, it is necessary to use a polyfunctional monomer having a plurality of different functional groups in the same molecule. However, in _order to use an AB _n- type monomer, the synthesis of the monomer is complicated.
Therefore, it has long been known that a method for synthesizing a multi-branched polymer using two commercially available polyfunctional monomers having different functional groups is theoretically possible, and in recent years many reports have been reported. (For example, refer to Patent Document 2).

Japanese Patent Laid-Open No. 9-40762 JP 2008-56894 A

However, in these proposed synthesis methods, when the reaction proceeds, the gel point is reached and an infusible insoluble cross-linked gel is formed. Therefore, the reaction is stopped in a state where the monomer remains before the gel point is reached. I have to let it.
In addition, since the raw material must be used excessively, the manufacturing cost increases.
In addition, it is difficult to control the reaction, and the development of a technique for suppressing gelation is desired.

  Further, in the production method described in Patent Document 2, it is necessary to once form an intermediate product, and the yield of the multibranched polyester is poor, so that the production cost is increased.

Furthermore, it is considered that a polyurethane cannot be produced satisfactorily by using only a multi-branched polyester, and even when a polyurethane is produced from the aforementioned Boltron (registered trademark), a linear polyester is mixed.
As a result of mixing linear polyester with poor biodegradability, the biodegradability of the resulting polyurethane was not always good.

  In order to solve the above-mentioned problems, in the present invention, it is possible to easily produce a multibranched polyester at a low cost, a method for producing a multibranched polyester, and a biodegradation using this multibranched polyester. The present invention provides a method for producing a polyurethane having excellent properties and a polyurethane having excellent biodegradability.

  In the method for producing a multibranched polyester of the present invention, a glycidol and a cyclic acid anhydride are reacted to synthesize a multibranched polyester.

That is, in the method for producing a multibranched polyester of the present invention, two types of cyclic monomers, glycidol and cyclic acid anhydride, are used, and there is only one reactive functional group at the start of the reaction. It is in the point which suppresses a crosslinking reaction by the combination of the monomer which produces | generates a reactive functional group.
Thereby, it is not necessary to use an excess monomer, and gelation accompanying the progress of the reaction does not occur at all.

The method for producing a polyurethane of the present invention comprises a step of synthesizing a multibranched polyester by the above-described method for producing a multibranched polyester of the present invention, and a step of synthesizing a polyurethane by reacting the multibranched polyester with a diisocyanate. Have
Thereby, since only the multibranched polyester excellent in biodegradability is used, the multibranched polyurethane excellent in biodegradability can be manufactured easily.

The polyurethane of the present invention can be obtained by reacting glycidol with a cyclic acid anhydride to synthesize a multibranched polyester and reacting the multibranched polyester with a diisocyanate.
Since the polyurethane of the present invention can be obtained by reacting a hyperbranched polyester with a diisocyanate, it has characteristics not found in general linear polyurethanes and is excellent in biodegradability. .

According to the above-described method for producing a multibranched polyester of the present invention, it is not necessary to use an excessive monomer, and therefore a multibranched polyester can be produced at low cost.
Moreover, since gelation does not occur as the reaction proceeds, the yield is good, and a multibranched polyester can be easily produced at low cost.

In addition, according to the method for producing a polyurethane of the present invention, a multi-branched polyurethane can be easily produced. Therefore, the polyurethane has characteristics that are not found in general linear polyurethanes and has excellent biodegradability. Polyurethane can be realized.
Moreover, according to the polyurethane of the present invention, it is possible to realize a polyurethane having characteristics not found in general linear polyurethane and excellent in biodegradability.

It is a figure which shows the signal paid attention and the time change of a spectrum by proton nuclear magnetic resonance measurement. It is a figure which shows the calibration curve used for the analysis of GPC measurement. It is a ¹³ C-NMR spectrum of the obtained product. It is a GPC elution curve of a reaction material. It is a FT-IR spectrum of A, B HBPE and HBPE-HDI. 2 is a DSC thermogram of HBPE and HBPE-HDI. It is a figure which shows the temperature dependence of mass loss in the thermogravimetric analysis measurement of HBPE-HDI. It is a figure which shows the temperature dependence of the storage elastic modulus (E ') and loss tangent (tan-delta) of HBPE-HDI. It is the stress-strain curve obtained by the tensile test of HBPE-HDI.

  In the method for producing a multibranched polyester of the present invention, as described above, glycidol and a cyclic acid anhydride are reacted to produce a multibranched polyester (HBPE).

Glycidol has a three-membered cyclic ether at one end of a chain molecule and a primary alcohol at the other end of the chain molecule, as shown in the following chemical formula.

Examples of the cyclic acid anhydride include glutaric anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, and adipic anhydride.
For example, a multibranched polyester can be produced by using one or more materials selected from these materials.
The chemical structure of these cyclic acid anhydrides is as shown in the following chemical formula.

  Of course, not only these cyclic acid anhydrides but also other cyclic acid anhydrides can be used.

When the glycidol and the cyclic acid anhydride are reacted, these raw materials (glycidol and the cyclic acid anhydride) are mixed in a solvent, and a catalyst is added if necessary.
As the solvent, for example, tetrahydrofuran (THF) can be used.
As the catalyst, for example, triethylamine (TEA) can be used.

A hyperbranched polyester (HBPE) can be obtained by performing a reaction using these raw materials (glycidol and cyclic acid anhydride), a solvent, and a catalyst.
The reaction at this time is shown in the following chemical reaction formula.

  By producing a hyperbranched polyester by such a reaction, there is an advantage that it is not necessary to use an excessive monomer, and that no gelation occurs as the reaction proceeds.

The above-mentioned Boltorn (registered trademark) and the like are limited to one type of raw material, and in Patent Document 1 and Patent Document 2, the ratio of two types of monomers is 1: 1.
On the other hand, in the production method of the present invention, the mixing ratio of the two types of raw cyclic monomers (glycidol and cyclic acid anhydride) is not limited to 1: 1 and can be other ratios. .
The structure of the multibranched polyester to be produced can be changed by changing the mixing ratio of the two kinds of raw cyclic monomers (glycidol and cyclic acid anhydride).
Thereby, it is possible to produce multi-branched polyesters having various structures.
For example, a hyperbranched polyester having the following structure is obtained.

Moreover, in the manufacturing method of the polyurethane of this invention, a multibranched polyester and diisocyanate are made to react using the multibranched polyester obtained by the above-mentioned manufacturing method, and a polyurethane is synthesize | combined.
Thereby, since multibranched polyester is used, a multibranched polyurethane can be easily manufactured.
It is also possible to produce a multi-branched polyurethane that has characteristics not found in general linear polyurethanes and is excellent in biodegradability.

The polyurethane of the present invention can be obtained by reacting a multibranched polyester with a diisocyanate using the multibranched polyester obtained by the above-described production method.
Thereby, it is possible to realize a polyurethane having characteristics not found in general linear polyurethane and excellent in biodegradability.

Further, when synthesizing polyurethane using the above-described Boltorn (registered trademark) as a multi-branched polyester, it has been considered that it is necessary to mix raw materials having a linear structure to some extent in order to synthesize polyurethane.
On the other hand, in the method for producing a polyurethane of the present invention, a flexible polyurethane can be produced by using a multibranched polyester without mixing a linear polyester having poor biodegradability.

As the diisocyanate, for example, hexamethylene diisocyanate can be used.
Of course, not only hexamethylene diisocyanate but also other diisocyanates may be used.

When the multibranched polyester and the diisocyanate are reacted, these raw materials (multibranched polyester and diisocyanate) are mixed in a solvent.
As the solvent, for example, tetrahydrofuran (THF) can be used.

  A polyurethane is obtained by performing a reaction using these raw materials (multi-branched polyester and diisocyanate) and a solvent.

(Example)
Subsequently, a hyperbranched polyester was actually produced by the production method of the present invention, a polyurethane was further produced from the hyperbranched polyester, and the properties of the obtained hyperbranched polyester and polyurethane were examined.

<1. Raw material>
Glycidol (2,3-epoxy-1-propanol) and glutaric anhydride were used without purification.
To these, tetrahydrofuran (THF; boiling point 66 ° C.) as a solvent and triethylamine (TEA; boiling point 89.7 ° C .; all manufactured by Wako Pure Chemical Industries, Ltd.) as a catalyst were distilled and used.
The chemical structure of these raw materials is shown below.

<2. Synthesis method>
In 150 ml of distilled THF, 85.07 g (0.75 mol) of glutaric anhydride was dissolved and added to an eggplant flask in a nitrogen atmosphere containing 55.20 g (0.75 mol) of glycidol.
Then, 0.39 g (3.9 mmol) of distilled triethylamine was added, and the mixture was reacted with stirring in an oil bath at 60 ° C. for 72 hours.
The viscosity of the reaction solution increased with the lapse of the reaction time.

Details of the reaction at this time are shown in the following chemical reaction formula.

That is, first, glycidol and a cyclic acid anhydride are reacted one by one to give the compound (I).
Furthermore, the carboxyl group at the terminal of the compound (I) attacks either the α carbon or β carbon of the glycidyl group of other glycidol, and the glycidyl group opens. In the case of α carbon, the structure is (II), and in the case of β carbon, the structure is (III).
Three types of structures can be obtained from the structure (II). Two types of structures can be obtained from the structure of (III). There are cases of straight connection and branching.
These processes are repeated to obtain a multi-branched polyester branched in a dendritic manner as shown at the end.

During the reaction, in order to follow the reaction, a sample of the reaction process was taken every arbitrary time, and proton nuclear magnetic resonance ( ¹ H-NMR) measurement was performed.
The sampling time was 0 hour (when the raw materials were mixed), 1 hour, 2 hours, 6 hours, 12 hours, 24 hours, 36 hours, 48 hours, 60 hours, and 72 hours.
Furthermore, 0.09 g of the collected sample was dissolved in 0.6 ml of deuterated dimethyl sulfoxide (DMSO-d ₆ ) to obtain a measurement sample.
For the measurement, a superconducting multi-nuclide magnetic resonance apparatus JNM-GX400 (400 MHz, manufactured by JEOL Ltd.) was used, and the number of integration was 8 times.

As shown in the upper diagram of FIG. 1, signals A and B of glutaric anhydride, signals C, D, E, F, and G of glycidol, signals H and I of THF, and signals J and K of TEA The reaction was followed by paying attention to the signals, signals A ′ and E ′ of compound (I).
Among the signals in the upper diagram of FIG. 1, the signals A and B of glutaric anhydride, the signals C and D of glycidol, and the signal E ′ of compound (I) disappeared in the ¹ H-NMR spectrum. After confirming the above, the reaction was terminated.

After completion of the reaction, THF was distilled off under reduced pressure using an evaporator and an oil rotary pump to obtain a hyperbranched polyester.
The obtained reaction product was a yellow transparent viscous product.

The results of reaction tracking by ¹ H-NMR measurement are shown in the lower part of FIG.
As shown in the lower diagram of FIG. 1, the following signals were observed.
The A proton signal of glutaric anhydride was observed at 1.9 ppm, and the B proton signal of glutaric anhydride was observed at 2.7 ppm.
A signal of C proton of glycidol was observed around 2.7 ppm, a signal of D proton of glycidol was observed at 3.0 ppm, and signals of E and F protons of glycidol were observed around 3.3 to 3.4 ppm.
Signals of H and I protons of THF as a solvent were observed at 3.6 ppm and 1.7 ppm.
Signals of the TE and J protons of the catalyst TEA at 2.4 ppm and 1.1 ppm were observed.
In addition, two doublet signals were observed at 4.4 ppm. This is expected to be a signal derived from both E 'protons in reactant (I).

Here, paying attention to the signals of 4.4 ppm and 3.2 ppm, these signals decrease after increasing up to 6 hours of reaction time. From this, the signal of 3.2 ppm is considered to be the A ′ proton of the compound (I) in the upper diagram of FIG.
This is because the signal of glutaric anhydride at 1.9 ppm was not observed in the time zone where the signals at 4.4 ppm and 3.2 ppm began to decrease (6-72 hours), and 3.9-4.1 ppm. Shows a signal expected to be D ′, D ″ methine proton, and therefore, the chemical shift of A ′ proton is expected to shift to a low magnetic field by ring-opening addition of carboxyl group to glycidyl group. Because. However, detailed structural identification was not possible.
Moreover, the signal which D ', D''methine proton shows has appeared in the wide range of 3.9-4.1 ppm. The reason for this is that the carboxyl group attacked either the α-carbon or β-carbon of the glycidyl group shown in the chemical reaction formula, and the molecular skeleton became very complex, so the spectrum was broadened overall. It is done.

<3. Structural analysis of HBPE>
Next, various measurements were performed in order to analyze the structure of the obtained reaction product (HBPE).

(Measurement of carbon nuclear magnetic resonance spectrum ( ¹³ C-NMR))
Carbon nuclear magnetic resonance spectrum ( ¹³ C-NMR) measurement of the reaction product was performed.
About 0.1 g of the reaction product was dissolved in 0.6 ml of deuterated dimethyl sulfoxide (DMSO-d ₆ ) to prepare a measurement sample.
For the measurement, a superconducting multi-nuclide magnetic resonance apparatus JNM-GX400 (400 MHz, manufactured by JEOL Ltd.) was used, and the number of integration was 512.

(Gel permeation chromatography (GPC) measurement)
In order to obtain the molecular weight and molecular weight distribution of the reaction product, gel permeation chromatography (GPC) measurement was performed.
20 mg of the reaction product was weighed, and a solution prepared with 5 ml of distilled THF was filtered through a membrane filter to obtain a measurement sample.
And about 25 microliters was inject | poured into the sample injection part of the measuring apparatus (LIQUID CHROMATOGRAPHLC-6A, Shimadzu Corporation Corp.) with the syringe, and the measurement was performed. The dissociation solution uses THF, the column uses Shodex GPC KF 804 (separation range 500 to 4.0 × 10 ⁵ Da), the detector uses a differential refractive index (RI) detector, and the column temperature is 40. Measurement conditions were 2 ° C. and a flow rate of 1.0 ml / min.

Using the GPC curve obtained by the measurement, the analysis was performed according to the following procedure.
(1) Divide the obtained GPC curve for each elution time.
(2) A base line is drawn at the beginning and end of the peak of the obtained GPC curve, and the height (hi) to the curve is obtained.
(3) Using a calibration curve, determine the molecular weight at each elution time. When the molecular weight of the component i of the molecular weight M _i of the N _i, the number average molecular weight (M _n) and weight average molecular weight (M _w), was calculated molecular weight distribution (M _w / M _n). Monodisperse polystyrene was used as a standard sample.
The relationship between the molecular weight of polystyrene and the elution time is shown in Table 1, and the prepared calibration curve is shown in FIG.

(Acid value measurement)
Any weight of HBPE dried under reduced pressure was dissolved in distilled methanol and titrated with a 0.1 N (N) sodium hydroxide-methanol solution. This operation was performed five times, and the results of three times excluding the lowest and highest titration values of the sodium hydroxide-methanol solution were averaged, and the acid value (X) of HBPE was calculated from the following formula (A). Asked. In addition, the phenolphthalein-methanol solution prepared to 0.1 wt% was used for the indicator.
X = (NaOH titration amount per 1 g of HBPE × N × f) / 1000 (A)
N: Normality (0.1N)
f: Factor (1.092)

(Measurement results and discussion)
First, the results of structure identification by ¹³ C-NMR measurement will be described.
The chemical structures of the terminal unit (T _1,2 , T _1,3 ), the unbranched unit (L _1,2 , L _1,3 ), and the branched unit (D) are shown in the following chemical formula.

Moreover, the structure of each unit shown in this chemical formula and the ¹³ C-NMR spectrum of the obtained product are shown in FIG.
Each obtained spectrum was assigned by a known method.
In the obtained spectrum, the chemical shift of the signal derived from the structure derived from glutaric anhydride does not depend on the chemical structure, and the β-position carbon signal from the carbonyl group (W = a, a ′, a ₁ ′, a '', a ₁ ″) are all observed at 20.2 ppm, and carbon signals at the α-position from the carbonyl group (X = b, b ′, b ₁ ′, b ″, b ₁ ″) are all 32. It was observed at 8 ppm.
In contrast, the chemical shifts of signals derived from glycidol (Y = c ′, c ₁ ′, c ″ and Z = d, d ′, d ″, d ₁ ″) vary greatly depending on the structure, Each appeared in a wide range of 59 to 76 ppm.
The signal of the c ″ carbon of 1,2-linear units (L _1,2 ) at 59.9-60.2 ppm and the c ₁ ′ carbon of _1,3 -terminal units (T _1,3 ) at 63.0 ppm The signal of the c ′ carbon of the 1,2-terminal unit (T _1,2 ) was observed at 63.4 ppm.
The d carbon of the dendritic unit (D) is 62.2 ppm, the signal of the d ″ carbon of L _1,2 is 62.7 ppm, and the signal of the d ′ carbon of T _1,2 is 65.2 ppm. A signal of d ₁ ″ carbon of _1,3 -linear units (L _1,3 ) was observed at 9 ppm.
The m carbon signal of L _1,3 at 66.6 ppm, the m carbon of D at 69.2 ppm, the m carbon signal of T _1,2 at 69.7 ppm, and the L _1,2 m at 72.4 ppm A carbon signal was observed at 75.9 ppm, and a m _1,3 carbon signal of T _1,3 was observed.
The carbon signal of the ester group was observed at 172.8 ppm, and the carbon signal of the terminal carboxyl group was observed at 174.6 ppm.

  Here, the chemical shifts of Y and Z are shown in Table 2, and the chemical shift of methine carbon derived from the structure of glycidol is shown in Table 3.

  From the above, it is considered that the structure of the obtained sample has a structure as shown in the chemical formula.

Next, the molecular weight obtained by determination of the molecular weight by GPC measurement, etc. are shown.
The GPC elution curve of the reaction product is shown in FIG. 4, and the number average molecular weight (M _n ), weight average molecular weight (M _w ) and molecular weight distribution (M _w / M _n ) of the obtained HBPE estimated from the GPC elution curve are shown. These are shown in Table 4, respectively.

  As shown in Table 4, the molecular weight and molecular weight distribution of the product were 1900, 2800 and 1.47, respectively.

Note that the actual molecular weight of the multibranched polymer is rarely formed by aggregation of the hydroxyl groups of the branched polymer, so the value estimated in terms of standard polystyrene may be larger than the actual molecular weight.
For this reason, in order to obtain | require the exact value of molecular weight of a product, it is thought that it is necessary to perform a gel permeation chromatograph-multi-angle laser light scattering (GPC-MALLS) measurement.

  Next, Table 5 shows the results of acid value measurement of the hyperbranched polyester.

From the results of the three titrations in Table 5, the COOH concentration per 1.0 g of the multibranched polyester was 2.017 × 10 ⁻³ mmol / g.
From this, it was revealed that the obtained hyperbranched polyester has a carboxyl group.

<4. Production of polyurethane>
Subsequently, polyurethane (PU) was produced using hyperbranched polyester (HBPE).
As raw materials, multi-branched polyester (HBPE) is used as a polyol, hexamethylene diisocyanate (HDI; bp. 255 ° C .; manufactured by Nippon Polyurethane Industry Co., Ltd.) is used as a diisocyanate, and THF (manufactured by Wako Pure Chemical Industries, Ltd.) is used as a solvent. ) Was distilled and used.
The chemical structure of these raw materials is shown in the following chemical formula.

In 30 ml of distilled THF, 10.00 g of a multibranched polyester (0.05 mol of hydroxyl group) dried under reduced pressure for 5 hours at an oil bath temperature of 80 ° C. in a nitrogen atmosphere was dissolved, and 4.47 g (0.4. 027 mol) was added, and the mixture was stirred for 30 seconds with a 90 ° reciprocating stirring device, and poured into a petri dish coated with a fluorine release agent (Daikin GA-6010 manufactured by Daikin Industries).
Thereafter, it was dried and cured in an oven at 80 ° C. for 72 hours to obtain a polyurethane.

Here, assuming that one molecule of glutaric anhydride and glycidol is reacted one by one, when the polymerization degree n is n = 1, there are two hydroxyl groups in one unit of the multi-branched polyester, and n = 2 In this case, the number of hydroxyl groups in one unit of the multi-branched polyester is 1.5, and as the degree of polymerization n increases, the number of hydroxyl groups in one unit of the multi-branched polyester is 1. Converge to.
From this, the compounding ratio K was calculated on the assumption that 1 unit of hydroxyl group of the hyperbranched polyester is 1, and K = [NCO] / [OH] = 1.0.

  The property of the obtained product was a sheet having a high elastic modulus as compared with general polyurethane (PU) having a transparent yellow color.

  Therefore, the sample name was HBPE-HDI using HBPE, which is an abbreviation for polyol as a raw material, and HDI, which is an abbreviation for isocyanate.

<5. Measurement of properties of polyurethane>
In order to investigate the characteristics of the obtained polyurethane (HBPE-HDI), various physical properties were measured.

(Density measurement)
Each sample was weighed in air and water, and the density was calculated from the measured weight. The weight measurement was performed five times for each sample, and the average value of the remaining three measurement values excluding the maximum value and the minimum value was used as the density. The density (d _p ) of the sample was obtained from the following formula (1).

After weighing the thin copper wire (w ₁ ), the weight (W ₁ + w ₁ ) when the sample was suspended was weighed.
Next, after weighing the copper wire and the weight of the sample (W ₂ + w ₂ ) when immersed in water, the sample was removed and the weight (w ₂ ) of the copper wire when immersed in water to the same level was weighed. .
From these values, the formula (1) is expressed by the following formula (2). Here, W ₁ , W _2, and d _w are the weight (g) of the sample in air, the weight (g) of the sample in water, and the density of water (g / cm ³ ) at the measured water temperature, respectively.

(Swelling test)
Next, the sample was subjected to a swelling test.
The test piece was precisely weighed, toluene (Wako Pure Chemical Industries, Ltd.) was used as a nonpolar solvent, and N, N-dimethylacetamide (DMA; manufactured by Wako Pure Chemical Industries, Ltd.) was used as a polar solvent, and a constant temperature of 60 ° C. Swelled in the bath.
Samples were removed from the solvent at appropriate time intervals, the surface was gently wiped with filter paper, and the weight of the sample was weighed. After the sample reached equilibrium swelling, it was dried to a constant weight in a vacuum drying oven at 60 ° C. The gel fraction g was determined from the following formula (3). Here, W is the weight of the unswelled sample and W _b is the weight of the dry sample. The degree of swelling q was determined by the following formula (4). Here, Q is the volume ratio of the sample at equilibrium swelling shown in the following formula (5), W _a is the weight of the equilibrium swelling sample, d _s is the density of the solvent (DMA density d _{s at} 60 ° C. = 0. 940 g / cm ³ , toluene density d _s = 0.864 g / cm ³ ), d _p is the density of the sample.

(Fourier transform infrared spectroscopy (FT-IR) spectrum measurement)
In order to identify the structure of the obtained HBPE-HDI, the measurement was performed by the Attenuated total reflection (ATR) method using a Bio-Rad FT3000 type FT-IR measuring apparatus.
An MCT detector was used as the detector, and the measurement range was 500 to 4000 cm ⁻¹ and the number of integrations was 32 times.

(Differential scanning calorimetry (DSC) measurement)
Differential scanning calorimetry (DSC) measurement of the obtained HBPE-HDI was performed.
About 5 mg of finely chopped HBPE-HDI was weighed and placed in a simple sealed cell to prepare a measurement sample. Aluminum was used as the reference sample. The measurement was performed in a nitrogen gas atmosphere using a Thermo Plus Station (manufactured by Rigaku Corporation) and a differential scanning calorimeter DSC8230 (manufactured by Rigaku Corporation). The measurement was performed by cooling the sample with liquid nitrogen to about −140 ° C., under a temperature range of −140 to 250 ° C., a nitrogen flow rate of 20 ml / min, and a temperature rising rate of 10 ° C./min.

(Thermogravimetric analysis (TGA) measurement)
Thermogravimetric analysis (TGA) measurement of the obtained HBPE-HDI was performed.
About 15 mg of the obtained sample was weighed, placed in an open aluminum cell, and measured using Thermo Plus Station (manufactured by Rigaku Corporation) and a thermobalance (TG8120). The measurement conditions were a heating rate of 10 ° C./min, a temperature range of 25 ° C. to 550 ° C., and the measurement atmosphere was an air atmosphere.

(Dynamic viscoelasticity measurement)
Using the obtained HBPE-HDI, dynamic viscoelasticity was measured.
From the HBPE-HDI sheet, a strip-shaped test piece having a width of 5 mm was cut out and used for measurement. The width and thickness of the test piece were measured at three locations with a micrometer, and the average values were taken as the width and thickness.
Then, dynamic viscoelasticity measurement was performed using a thermal analysis rheology system (DMS6100) manufactured by Seiko Instruments Inc. The measurement conditions were a temperature rising rate of 2.0 ° C./min, a temperature range of −100 to 300 ° C., a measurement frequency of 1.10 Hz, a minimum tension of 25 mN, a tension / compression force gain = 1.2, a strain amplitude of 10 μm, and an initial length of 10,000 μm ( 10 mm).

(Tensile test)
From the HBPE-HDI sheet, a strip-shaped test piece having a width of 5 mm was cut out and used for measurement. The width and thickness of the test piece were measured at three locations with a micrometer, and the initial cross-sectional area was calculated using the average value thereof.
And the tensile test was done using the Tensilon universal testing machine (RTE-1210) by Orientec Co., Ltd., and the stress-strain relationship was measured. The measurement was performed indoors using a camera using a 5 kgf load cell under the conditions of an initial sample length of 20 mm and a crosshead speed of 5 mm / min.
The following formulas (6) and (7) were used to calculate the Young's modulus.
In viscoelastic body,
α · σ = E · ε ⁿ (0 <ε ≦ 1) (6)
Holds. Taking the logarithm of both sides in the above formula,
log (α · σ) = logE + nlogε (7)
It becomes. Here, α is an elongation ratio, σ is stress, E is Young's modulus, ε is strain, n is a proportionality constant (complete viscosity response when n = 0, complete elastic response when n = 1, viscoelasticity when 0 <n <1 Response).
Using the data obtained until the elongation ratio of the sample reached 10%, the log (α · σ) vs. log ε were plotted, and the Young's modulus was calculated from the intercept value on the vertical axis.

(Hydrolyzable)
The hydrolyzability of HBPE-HDI was examined.
After the weight of the obtained HBPE-HDI was measured, the HBPE-HDI was immersed in a 1 mmol / L aqueous sodium hydroxide solution and held as it was for 77 days.
After 77 days, the weight was measured to examine the change in weight.

(Measurement results and discussion)
Then, the measurement result of the physical property measurement of HBPE-HDI is demonstrated.
First, FIG. 5 shows Fourier transform infrared spectroscopy (FT-IR) spectra of HBPE used as a polyol and the obtained HBPE-HDI. Figure 5A shows the spectrum of both 4000~3000cm ^-1, Figure 5B shows the spectrum of both 2000~1400cm ^-1.
In FT-IR spectrum of HBPE, the stretching vibration ν (C = O) is observed in the carbonyl groups derived from the ester group to 1735 cm ^-1, stretching vibration of the hydroxyl group derived from the terminal hydroxyl group to 3447cm ^-1 ν (OH) Was observed.
In FT-IR spectrum of HBPE-HDI, the absorption band of amide II derived from the urethane groups (ν (C = O) + δ (NH)) was observed at 1535cm ^-1, the carbonyl group of the urea group in 1651 cm ^-1 Stretching vibration (ν (C = O) _urea ) derived from cis was observed, and stretching vibration (ν (C = O _H-bond )) of hydrogen-bonded carbonyl group derived from urethane group was observed near 1702 cm ^−1. , The peaks of the stretching vibration of the carbonyl group derived from the ester group (ν (C = O)) and the stretching vibration of the free carbonyl group derived from the urethane group (ν (C = O _free )) were observed at 1732 cm ^−1. It was.
From this, it is considered that the target PU was obtained by the reaction between HBPE and HDI.

  Next, as a measurement result of the density of the obtained HBPE-HDI and a measurement result of the swelling test, the density, gel fraction, and swelling degree are shown in Table 6.

From Table 6, the density of the obtained HBPE-HDI (multi-branched polyurethane) was almost the same density as the polyurethane obtained using linear polyester.
Moreover, since the value of the gel fraction was sufficiently high, it was found that the obtained HBPE-HDI was sufficiently polymerized.

Next, FIG. 6 shows a DSC thermogram of HBPE used as a polyol and the obtained HBPE-HDI as a result of differential scanning calorimetry (DSC) measurement.
As shown in FIG. 6, the glass transition temperatures (T _g ) of HBPE and HBPE-HDI used as polyols were observed at −26.5 ° C. and 13.2 ° C., respectively. That, the _{T g} of HBPE-HDI is compared to the _{T g} of HBPE, it shifted to the high temperature side. This is considered to be due to a decrease in molecular mobility due to the chemical bonding of HBPE and an increase in molecular weight due to the reaction.
Also, no melting peak due to the crystal component was observed.

Next, as a result of thermogravimetric analysis (TGA) measurement, the temperature dependence of mass loss in the thermogravimetric analysis measurement of the obtained HBPE-HDI is shown in FIG.
As shown in FIG. 7, HBPE-HDI thermally decomposed around about 250 ° C., and weight loss started.

Next, FIG. 8 shows the temperature dependence of the storage elastic modulus (E ′) and loss tangent (tan δ) obtained by the dynamic viscoelasticity measurement of HBPE-HDI as a result of the dynamic viscoelasticity measurement.
As shown in FIG. 8, a rapid decrease in E ′ accompanying α relaxation and the beginning of tan δ rise were observed around 10 ° C. This is, corresponding to the _{T g} in DSC measurement.
Moreover, although it had a crosslinked structure, it behaved like a fluid at around 250 ° C. About this, since it corresponded to the thermal decomposition start temperature of TGA measurement, and the sample after dynamic viscoelasticity measurement was yellowed, the urethane bond was cut by thermal decomposition, and the characteristics of the linear polymer It is thought that it behaved like a certain flow.
Further, as the temperature increased, the value of E ′ in the rubber-like flat region increased, indicating entropy elasticity. This is because, when heat is applied to the crosslinked polymer chain, the elastic modulus increases due to an increase in the contracting force of the molecular chain. As can be seen from FIG. 8, entropy elasticity is exhibited in a rubbery flat region in a wide range of 50 ° C. to 250 ° C.
Sub-dispersion was observed around -80 ° C. This is considered to be caused by the rotational movement of the methyl group directly bonded to the main chain and the rotational movement of the side chain in the binding potential created by the nearby atoms. Here, it is considered that the branch unit is a main chain, and the terminal unit and the unbranched unit are side chains.
Moreover, the shoulder derived from a rearrangement crystal | crystallization and melting | dissolving was not observed, and this result also corresponded with the result of DSC measurement.

  From these results, it can be seen that a polyurethane having chemical crosslinks made of amorphous polyester was obtained.

  Next, FIG. 9 shows a stress-strain curve obtained by the tensile test of HBPE-HDI as a result of the tensile test. Table 7 shows the Young's modulus, Tensile strength, and Strain at Break as the obtained mechanical property values.

With knowledge of normal polyurethanes, polyurethanes synthesized using polyfunctional polyols should be very hard and brittle samples with no suppleness.
However, since the Young's modulus of the obtained HBPE-HDI (multi-branched polyurethane) is lower than that of polyurethane obtained using a linear polyester, it has been revealed that it is rich in flexibility. The break stress was not significantly different from polyurethane obtained using linear polyester. Surprisingly, it was revealed that the obtained HBPE-HDI has flexibility because it is greatly distorted (stretched).

Next, the measurement result of hydrolyzability was 31% weight loss in 77 days.
After planting the seeds of the crops, the period of time when the vinyl protection is not needed is about 2 months, and the 31% weight loss means that the polyurethane is in a shabby state, so when the crops germinate There is no need to remove the protected vinyl.
As a comparative example, polyurethane obtained from linear polyester does not decompose at all in a 1 mmol / L sodium hydroxide aqueous solution.
Thus, it can be seen that the 1 mmol / L sodium hydroxide aqueous solution is a weak basic environment, and HBPE-HDI is decomposed even in such a weak basic environment and has sufficient decomposability.
Therefore, this HBPE-HDI (multi-branched polyurethane) can realize a polyurethane having excellent biodegradability.

  The present invention is not limited to the above-described embodiment, and various other configurations can be taken without departing from the gist of the present invention.

[0003]
In addition, since the yield of the multibranched polyester is poor, the production cost increases.
[0010]
Furthermore, it is considered that a polyurethane cannot be produced satisfactorily by using only a multi-branched polyester, and even when a polyurethane is produced from the aforementioned Boltron (registered trademark), a linear polyester is mixed.
As a result of mixing linear polyester with poor biodegradability, the biodegradability of the resulting polyurethane was not always good.
[0011]
In order to solve the above-mentioned problems, in the present invention, it is possible to easily produce a multibranched polyester at a low cost, a method for producing a multibranched polyester, and a biodegradation using this multibranched polyester. The present invention provides a method for producing a polyurethane having excellent properties and a polyurethane having excellent biodegradability.
[Means for solving problems]
[0012]
[0013]
[0014]
The method for producing a polyurethane according to the present invention comprises a step of synthesizing a multibranched polyester by reacting glycidol and a cyclic acid anhydride, and a step of synthesizing a polyurethane by reacting the multibranched polyester and diisocyanate. Have.
Thereby, since only the multibranched polyester excellent in biodegradability is used, the multibranched polyurethane excellent in biodegradability can be manufactured easily.
[0015]
The polyurethane of the present invention is obtained by reacting glycidol with a cyclic acid anhydride,

［００２１］
環状酸無水物としては、例えば、無水グルタル酸、無水コハク酸、無水マレイン酸、無水フタル酸、無水アジピン酸等が挙げられる。
そして、例えば、これらの材料から選ばれる１種以上の材料を使用することにより、多分岐性ポリエステルを製造することができる。
これらの環状酸無水物の化学構造は、下記の化学式の通りである。[0005]
FIG.
FIG. 8 is a graph showing the temperature dependence of storage elastic modulus (E ′) and loss tangent (tan δ) of HBPE-HDI.
FIG. 9 is a stress-strain curve obtained by a tensile test of HBPE-HDI.
[Mode for Carrying Out the Invention]
[0019]
In the method for producing a multibranched polyester according to the present invention, as described above, glycidol and a cyclic acid anhydride are reacted to produce a multibranched polyester (HBPE).
[0020]
Glycidol has a three-membered cyclic ether at one end of a chain molecule and a primary alcohol at the other end of the chain molecule, as shown in the following chemical formula.
[Chemical 1]

[0021]
Examples of the cyclic acid anhydride include glutaric anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, and adipic anhydride.
For example, a multibranched polyester can be produced by using one or more materials selected from these materials.
The chemical structure of these cyclic acid anhydrides is as shown in the following chemical formula.

［００２２］
もちろん、これらの環状酸無水物に限らず、他の環状酸無水物も使用することが可能である。
［００２３］
グリシドールと環状酸無水物とを反応させる際には、これらの原料（グリシドールと環状酸無水物）を溶媒中で混合して、必要に応じて触媒を加える。
溶媒としては、例えば、テトラヒロドフラン（ＴＨＦ）を使用することができる。
触媒としては、例えば、トリエチルアミン（ＴＥＡ）を使用することができる。
［００２４］
これらの原料（グリシドールと環状酸無水物）、溶媒、触媒を使用して、反応を行うことにより、多分岐性ポリエステル（ＨＢＰＥ）が得られる。
このときの反応を下記の化学反応式に示す。
［００２５］[0006]
[Chemical 2]

[0022]
Of course, not only these cyclic acid anhydrides but also other cyclic acid anhydrides can be used.
[0023]
When the glycidol and the cyclic acid anhydride are reacted, these raw materials (glycidol and the cyclic acid anhydride) are mixed in a solvent, and a catalyst is added if necessary.
As the solvent, for example, tetrahydrofuran (THF) can be used.
As the catalyst, for example, triethylamine (TEA) can be used.
[0024]
A hyperbranched polyester (HBPE) can be obtained by performing a reaction using these raw materials (glycidol and cyclic acid anhydride), a solvent, and a catalyst.
The reaction at this time is shown in the following chemical reaction formula.
[0025]

Claims (4)

A method for producing a multibranched polyester in which a glycidol and a cyclic acid anhydride are reacted to synthesize a multibranched polyester.   The method for producing a multibranched polyester according to claim 1, wherein the cyclic acid anhydride is one or more materials selected from glutaric anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, and adipic anhydride. Reacting glycidol with a cyclic acid anhydride to synthesize a hyperbranched polyester;
A process for producing polyurethane by reacting the multi-branched polyester with diisocyanate.   A polyurethane that can be obtained by reacting glycidol and a cyclic acid anhydride to synthesize a multibranched polyester and reacting the multibranched polyester with a diisocyanate.

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