JPH06256506A - Resin composition having biodegradation and its production - Google Patents

Abstract

PURPOSE:To obtain a composition synthesized by reacting a specified biodegradable resin, a cyclic amide and a cyclic lactone in the presence of a catalyst under a reduced pressure, having a repeating unit suitably containing ester units and amide units and exhibiting practical physical properties. CONSTITUTION:This resin has a repeating unit represented by formula I or II [R<1> and R<2> are each a group composed of a 2 to 12C straight chain methylene bonded to a 1 to 3C alkyl: (x) is 1 to 20: (y) is 1 to 200: (z) is 1 to 500], 5000 to 100000 molecular weight and 100 to 160 deg.C melting point. The resin is synthesized by reacting a cyclic amide of formula III with a cyclic lactone of formula IV in the presence of a catalyst under a reduced pressure. As the cyclic amide and the cyclic lactone, 5 to 80mol% epsilon-caprolactam, etc., and 20 to 95mol% beta-propiolactone, etc., are respectively used. As the catalyst, a metal-containing alkaline catalyst, etc., is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel biodegradable resin and a process for producing the same, and more specifically to a biodegradable resin composed of a biodegradable ester moiety and an amide moiety. Regarding the manufacturing method.

[0002]

2. Description of the Related Art Synthetic polymers are widely used in daily life. In recent years, as medical materials and agricultural materials, polymers having a new property of biodegradability have been attracting attention, and research and development have been conducted in connection with the waste treatment.

It has been conventionally known that polyester exhibits biodegradability, and for example, various copolyamide esters have been proposed. Specifically, for example, a copolyamide ester prepared by ring-opening copolymerization of a cyclic lactam and a cyclic lactone is known. The copolyamide ester is produced by reacting at about 100 ° C. under normal pressure, but has a drawback that it has a small molecular weight and a melting point of about 80 ° C. at room temperature even if it is liquid, and it is poor in practicality. is there. Further, various proposals have been made to prepare a copolyamide ester by an amide transesterification reaction between nylon and polyester (Japanese Patent Publication No. 56-38115, Japanese Patent Publication No. 55-18489, and Japanese Patent Publication No. 55-3).
No. 1207, Japanese Patent Publication No. 54-44749, Japanese Patent Publication No. 59-8365). However, these copolyamide esters are also low in molecular weight, and the reaction temperature during production is as high as 270 ° C., which is dangerous, and the cost is high because the polymer is once synthesized and then the exchange reaction is performed. There are drawbacks.

Further, in a blended product in which an aliphatic polyester and a polyamide are simply mixed or a polymer in which a polyester and a polyamide are combined in a high molecular weight, the polyester part is biodegraded, but the polyamide part is
Unless it is a low molecular weight oligomer, it is not biodegraded at all, and cannot be said to be a completely biodegradable polymer material. In addition, the conventional biodegradable synthetic polymer is unavoidably deteriorated in its original properties as the biodegradability is increased, and it is the fact that the synthesis is performed at an appropriate compromise.

[0005]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to provide a biodegradable material which has both high biodegradability and practicality as a general-purpose resin having a high molecular weight and which can be used as various molding materials. It is to provide a resin and a method for producing the same.

[0006]

According to the present invention, the repeating unit represented by the following general formula 5 (hereinafter referred to as repeating unit A) or the repeating unit represented by the following general formula 6 (hereinafter referred to as repeating unit B and Have a molecular weight of 5,000 to 1,000.
And a melting point of 100 to 160 ° C., a biodegradable resin is provided.

[0007]

[Chemical 5]

[0008]

[Chemical 6]

Further, according to the present invention, a cyclic amide represented by the following general formula 7 (hereinafter referred to as cyclic amide C) and a cyclic lactone represented by the following general formula 8 (hereinafter referred to as cyclic lactone D) are prepared. A method for producing the biodegradable resin is provided, which comprises reacting with a catalyst under reduced pressure.

[0010]

[Chemical 7]

[0011]

[Chemical 8]

The present invention will be described in more detail below.

The biodegradable resin of the present invention has the repeating unit A represented by the general formula 5 or the general formula 6
Having a repeating unit B represented by
It is a resin of 00000 and a melting point of 100 to 160 ° C. When the molecular weight is less than 5,000, the physical properties such as strength and elongation deteriorate, and when it exceeds 100,000, the synthesis is difficult and the yield remarkably decreases, so the above range is required. Further, if the melting point is less than 100 ° C, the strength and heat resistance are lowered, and if the melting point is more than 160 ° C, it is difficult to synthesize, and therefore the above range is required. Further, in the repeating units A and B, when R ¹ and R ² are linear methylenes having 13 or more carbon atoms, and when the alkyl group bonded to the linear methylene has 4 or more carbon atoms, the production is Have difficulty. Furthermore x
When it exceeds 20, the biodegradability is remarkably reduced and y
When the value exceeds 200, a resin having high practical utility cannot be obtained. In addition, the introduction ratio of the alkyl group having 1 to 3 carbon atoms which is bonded to the linear methylene group of R ¹ and R ^{2 in} the formula can be variously selected according to the desired application.

The biodegradable resin of the present invention is a resin in which an ester moiety having a repeating unit A or B and an amide moiety are randomly copolymerized, and therefore has both excellent biodegradability and practicality. The resin having the repeating unit A is
It is easily decomposed by lipase, esterase and the like, and the resin having the repeating unit B is easily decomposed by lipase, esterase, PHB depolymerase and the like.

In the method for producing a biodegradable resin of the present invention, the cyclic amide C represented by the general formula 7 and the cyclic lactone D represented by the general formula 8 are used as raw material components and the catalyst is decompressed under reduced pressure. Is characterized in that the reaction is carried out.

The cyclic amide C used in the production method of the present invention
Is a compound having a molecular weight of 71 to 449, and specific examples thereof include ε-caprolactam, δ-valerolactam, γ-butyrolactam, β-propiolactam and the like. The cyclic lactone D has a molecular weight of 8
6 to 450 compounds, specifically, for example, ε-caprolactone, δ-valerolactone, β-propiolactone, γ-butyrolactone, α-methyl-ε-caprolactone, α-methyl-δ-valerolactone, α -Methyl-
Preferable examples include β-propiolactone and α-methyl-γ-butyrolactone. At this time, when β-propiolactone is used as the cyclic lactone D,
A biodegradable resin represented by the repeating unit B can be obtained.

The amount of cyclic amide C and cyclic lactone D charged is preferably 5 to 80 mol% of cyclic amide C unit and 20 to 9 of cyclic lactone D unit in the obtained resin.
It is desirable that the content be 5 mol%. When the charged amount of cyclic amide C exceeds 80 mol%, that is, when the charged amount of cyclic lactone D is less than 20 mol%, the biodegradability is remarkably lowered, which is not preferable. Further, the charged amount of cyclic amide C is 5
When the amount is less than the mol%, that is, when the charged amount of the cyclic lactone D is more than 95 mol%, practical physical properties cannot be obtained, which is not preferable.

In the production method of the present invention, the cyclic amide C is used.
Examples of the catalyst used when reacting the lactone D with the cyclic lactone D include metal-containing alkali catalysts and metal-containing alkyl catalysts. Specifically, the metal-containing alkali catalysts include sodium, potassium, lithium, magnesium, Calcium, sodium hydroxide, potassium hydroxide,
Lithium hydroxide, magnesium hydroxide, calcium hydroxide, sodium methoxide, potassium methoxide, lithium methoxide, magnesium methoxide, calcium methoxide, sodium ethoxide, potassium ethoxide, lithium ethoxide, magnesium ethoxide, calcium ethoxy. , Sodium-t-butoxide, potassium-t-butoxide, lithium-t-butoxide,
Magnesium-t-butoxide, calcium-t-butoxide, etc. can be mentioned. Examples of metal-containing alkyl catalysts include alkyllithium such as methyllithium, ethyllithium, propyllithium and butyllithium; dialkyltin oxides such as dimethyltin oxide, diethyltin oxide, dipropyltin oxide and dibutyltin oxide; dimethylzinc and diethylzinc. , Dipropyl zinc such as dipropyl zinc and dibutyl zinc, and other active alkyl metals. The amount of the catalyst used is preferably 0.1 to 30 mol% with respect to the raw material components.

To carry out the reaction in the production method of the present invention,
For example, after mixing and melting the raw material components, in the presence of the catalyst, using a vacuum pump or the like, preferably under a reduced pressure of 1 mmHg or less, particularly preferably 0.01 to 0.5 mmHg, an inert gas (nitrogen, The inside of the reaction system is replaced with argon, etc., and the reaction temperature is 0 to 260 ° C., especially 0 to 160 ° C.
It is desirable to carry out the reaction for 1 to 72 hours. If the above reaction is not carried out under reduced pressure, the melting point and molecular weight of the obtained resin are low, and a practical resin cannot be obtained, which is not preferable. When the reaction temperature is lower than 0 ° C, the reaction takes a long time, and when it exceeds 260 ° C, workability is deteriorated and a decomposition reaction occurs as a side reaction, which is not preferable.

The biodegradable resin of the present invention can be obtained by purification by a known purification method such as reprecipitation after the completion of the above reaction.

[0021]

The biodegradable resin of the present invention has a specific repeating unit in which an ester partial unit and an amide partial unit of an oligomer degree are optimally blended, and has a specific molecular weight and melting point. It can be completely biodegraded in the natural environment such as soil, and can be rapidly used in rapid composting equipment under aerobic conditions known as a method for treating municipal waste, surplus sludge in sewage treatment, and waste. It can be biodegraded (combost), and can also be decomposed by lipase-producing bacteria, lipase-containing substances and the like. In particular, the biodegradable resin of the present invention obtained by reacting a cyclic amide with β-propiolactone as a raw material component is
Since it can be decomposed by PHB depolymerase-producing bacteria, PHB depolymerase-containing substances, etc., it is biodegraded very quickly.
Therefore, it is possible to select the decomposition rate in a wider range without causing the pollution problem as seen in non-degradable plastics.

The biodegradable resin of the present invention is
Since it can be processed into biodegradable fibers and films at a molding temperature of 100 to 160 ° C., it can be used for mulch films in the field of agriculture and forestry, pots and strings for planting trees, bags for pesticides and fertilizers, etc. Further, in the medical field, it can also be used as a surgical thread or a drug support that gradually releases drugs in the body.

[0023]

EXAMPLES The present invention will be specifically described below based on Examples and Comparative Examples, but the present invention is not limited thereto.

[0024]

Example 1 To 5.56 g of ε-caprolactam, 5.71 g of ε-caprolactone and 1.12 g of potassium-t-butoxide were added, and 0.5 mmHg in a nitrogen atmosphere.
A resin was obtained by carrying out a copolymerization reaction at 160 ° C. for 3 hours under reduced pressure. The obtained resin was purified by reprecipitation with methyl alcohol, and the yield was 84%. Further, the melting point measured by a differential scanning calorimeter is about 120 ° C., the intrinsic viscosity (in metacresol, 25 ° C.) is 1.17, and the molecular weight Mn is 200.
It was 00. The ¹ H-NMR spectrum and ¹³ C-NMR spectrum of the obtained resin were measured. The results are shown in FIGS. 1 and 2, respectively.

From the result of ¹ H-NMR spectrum shown in FIG. 1, the obtained resin shows that in the repeating unit A, R ¹ =
(CH ₂ ) ₃ , R ² = (CH ₂ ) ₃ , x = 1 to 10, y = 1
-10, z = 5-50, ε-caprolactam and ε
It was found to be a random copolymer of -caprolactone. In addition, from the result of ¹³ C-NMR spectrum of FIG. 2,
Since the carbonyl carbon signals of the ester unit and the amide unit were split into 173 ppm and 174 ppm, which were broad, a random bond between both units was observed.

Further, a resin was prepared under the same conditions as in the above copolymerization reaction except that the mixing ratio of ε-caprolactam and ε-caprolactone was changed as shown in Table 1, and the yield, melting point,
Intrinsic viscosity and molecular weight were measured. The results are shown in Table 1.

[0027]

[Table 1]

[0028]

COMPARATIVE EXAMPLE 1 To 5.56 g of ε-caprolactam, 5.71 g of ε-caprolactone and 1.12 g of potassium-t-butoxide were added, and the mixture was stirred at 160 ° C. in a nitrogen atmosphere under normal pressure.
A copolymerization reaction was carried out at ℃ for 3 hours to obtain a resin. The obtained resin was purified by reprecipitation with methyl alcohol, and the yield was 58%. The melting point is about 60 ° C, the intrinsic viscosity (in metacresol, 25 ° C) is 0.03, and the molecular weight is 5
It was 00.

[0029]

Example 2 After the reaction was carried out in the same manner as in Example 1, the reaction was further carried out at a reaction temperature of 270 ° C. for 2 hours and then at 200 ° C. for 5 hours to obtain a resin. The obtained resin was purified by reprecipitation with methyl alcohol, and the yield was 69%. The melting point is about 153 ° C and the intrinsic viscosity (in metacresol, 2
5 ° C.) was 2.40 and the molecular weight was 60,000.

Further, the NMR spectrum was measured in the same manner as in Example 1, and it was found that the obtained resin was a desired random copolymer.

[0031]

Example 3 The reaction was carried out under the same conditions as in Example 1 except that ε-caprolactone was replaced with 5.01 g of δ-valerolactone. As a result, the yield is 75%, the melting point is 110 ° C,
The intrinsic viscosity (in meta-cresol, 25 ° C.) was 1.12 and the molecular weight was 19000.

When the NMR spectrum was measured in the same manner as in Example 1, it was found that the obtained resin was a desired random copolymer.

Further, a resin was prepared under the same conditions except that the mixing ratios of ε-caprolactam and δ-valerolactone were changed as shown in Table 2, and the yield, melting point, intrinsic viscosity and molecular weight were measured. The results are shown in Table 2.

[0034]

[Table 2]

[0035]

Comparative Example 2 The reaction was carried out under the same conditions as in Comparative Example 1 except that ε-caprolactone was replaced with 5.01 g of δ-valerolactone. The obtained resin has a yield of 37% and a melting point of about 45.
℃, intrinsic viscosity (in meta-cresol, 25 ℃) is 0.0
2, the molecular weight was 400.

[0036]

Example 4 To 5.56 g of ε-caprolactam was added 3.60 g of β-propiolactone and 1.12 g of potassium-t-butoxide, and 0.5 mmHg was added in a nitrogen atmosphere.
The resin was obtained by carrying out a copolymerization reaction at 0 ° C. for 24 hours under reduced pressure. The obtained resin was purified by reprecipitation with methyl alcohol, and the yield was 75%. The melting point is 110
℃, intrinsic viscosity (in meta-cresol, 25 ℃) 1.1
0, the molecular weight was 18,000.

Further, when the NMR spectrum was measured in the same manner as in Example 1, it was found that the obtained resin was a desired random copolymer.

[0038]

[Example 5 and Comparative Example 3] Biodegradability of the resins synthesized in Examples 1, 3 and 4 using various enzymes (Example 5) and as a comparison, the biodegradability of existing resins shown in Table 3 (Comparative Example 3) was examined. As the enzyme, R. arrhizus lipase, pig liver esterase (trade name "Boehringer Mannheim", partially purified preparation by Yamanouchi Pharmaceutical Co., Ltd.) and RHB depolymerase produced by Pseudomonas lemoigne were used.

The biodegradability of the resin was determined by measuring the water-soluble total organic carbon (TOC) concentration produced by the reaction at 30 ° C. with a TOC analyzer manufactured by Shimadzu Corporation. Specifically, the polymer was added to a 100 ml Erlenmeyer flask so that the content of the ester component was 100 mg,
A phosphate buffer (pH 7.0) (400 μmol) and an enzyme solution were added to adjust the total amount to 10 ml, and the mixture was reacted at 30 ° C. for 16 hours using a rotary shaker (180 rpm).
The amounts of lipase and esterase in the reaction solution were adjusted so that the hydrolysis activity against olive oil was the same. The results are shown in Table 3.

From the results of Table 3, PLC and PPL are excellent in biodegradability, but their melting point is 95 ° C. or less, heat resistance and workability are poor, and practicability is low. On the other hand, it can be seen that the resin obtained by copolymerizing both of the present invention has a good melting point of 95 ° C. or higher and has biodegradability.

[0041]

[Table 3]

[Brief description of drawings]

FIG. 1 is the ¹ H-NM of the resin prepared in Example 1.
It is a figure which shows R spectrum.

FIG. 2 shows ¹³ C-NM of the resin prepared in Example 1.
It is a figure which shows R spectrum.

Claims (3)

[Claims] 1. A repeating unit represented by the following general formula 1, having a molecular weight of 5,000 to 100,000 and a melting point of 100 to 1
A resin having biodegradability, which is 60 ° C. [Chemical 1] 2. A repeating unit represented by the following general formula 2, having a molecular weight of 5,000 to 100,000 and a melting point of 100 to 1
A resin having biodegradability, which is 60 ° C. [Chemical 2] 3. A cyclic amide represented by the following general formula 3 and a cyclic lactone represented by the following general formula 4 are reacted under reduced pressure using a catalyst.
Alternatively, the method for producing a biodegradable resin according to 2 above. [Chemical 3] [Chemical 4]