JPH0859808A - Aliphatic polyester ether - Google Patents

Abstract

PURPOSE: To provide a biodegradable aliph. polyester ether having such a mol. wt. as to be maldable, the degradation of which proceeds in as short a period of time as possible when it is allowed to stand in environment. CONSTITUTION: An aliph. polyester ether comprises constituent units of the formula (1) and/or (2) and the formula (3), and has a no.-average mol. wt. of at least 30,000. In the formulae, (n), (m) and (l)are each an integer of at least 2; R1 is a 1-18C alkylene group or a cyclohexylene group; R2 is a 2-20C alkylene group [which may be substd. by an alkyl group(s) as a side chain(s)] or a cyclohexanedimethanol group; and R3 is an ethylene, propylene or tetramethylene group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high molecular weight aliphatic polyester ether which is decomposed by microorganisms in soil and can be used as a molded body. More specifically, it relates to the biodegradability of aliphatic polyester. The present invention relates to an aliphatic polyester ether obtained by block-copolymerizing a polyalkylene glycol in order to enhance it.

[0002]

BACKGROUND OF THE INVENTION Aliphatic polyesters, such as polyethylene succinate (PES) and polyethylene adipate (PEA), and polyenes produced by melt polycondensation of α, ω-aliphatic diols with α, ω-aliphatic dicarboxylic acids. Butylene succinate (PBS) is a polymer that has been known for a long time, and it has been confirmed that it can be manufactured at low cost and that it is biodegraded by microorganisms even when it is buried in the soil [Int. Biodetetration (Int. Bull.), Volume 11, 127
P. (1975) and Polymer Science Technology (Polym. Sci. Technol.), Vol. 3, p. 61 (197).
3)], but these polymers have poor thermal stability,
Since the decomposition reaction occurs at the time of polycondensation, it is usually 2,000
Only those having a molecular weight of about 6,000 were obtained, which was not sufficient for processing into fibers or films.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of previous investigations to increase the molecular weight of such aliphatic polyesters, the present inventors have found that titanium, antimony and germanium compounds are used as catalysts in a short time. We have found and proposed that the molecular weight can be increased to such an extent that it can be formed into a film or fiber (eg, Japanese Patent Application No.
-98851 and Japanese Patent Application No. 5-297330).

Therefore, aliphatic polyesters were synthesized by using these methods, molded and processed, and biodegradability was tested by burying in soil, immersing in activated sludge or the like. But,
Although it was confirmed that these aliphatic polyesters were completely biodegradable, it took 6 months or more for a film to be formed into a molded product, depending on the form and composition of the polyester before it completely decomposes and becomes unrecoverable. It turns out that it takes more than a year. Biodegradable plastic does not lose its strength during use, depending on its intended use,
After use, it is preferred that the strength be reduced as quickly as possible and then completely decomposed into carbon dioxide and water. As a method of accelerating the strength reduction of aliphatic polyester, a method of block-copolymerizing polyethylene glycol with aliphatic polyester has been reported [Journal Macromolecular Science-Chemistry (J. Macromo
l. Sci.-Chem.), A23, 411-422 (19).
86)]].

However, since the aliphatic polyester ether obtained by the above method has a low molecular weight, it is necessary to increase the molecular weight by using a chain extender such as adipic acid chloride in order to have fiber forming ability. Therefore, there are problems in that the reaction process has two steps, the operation is complicated, and the melting point and crystallinity of the obtained polymer are slightly lowered.

The present invention solves these problems and provides a novel aliphatic polyester ether having a molecular weight such that its strength is reduced in a shortest possible time when left in the environment and it can be molded. It is intended to be provided.

[0007]

Means for Solving the Problems As a result of various studies to solve the above problems, the present inventors have added polyalkylene glycol to an aliphatic polyester synthesized from a dicarboxylic acid or its derivative and a diol, It was found that the aliphatic polyester ether obtained by direct polycondensation is excellent in biodegradability, and has a molecular weight such that it can be molded and processed by itself, and based on this finding, the present invention was obtained. Arrived

That is, according to the present invention, an aliphatic polyester characterized by having the following general formulas (1) and / or (2) and (3) as constitutional units and having a number average molecular weight of at least 30,000: The main point is ether.

[0009]

Embedded image

[Wherein n, m and l are integers of 2 or more, R ₁ is an alkylene group or cyclohexylene group having a carbon number of ₁ to 18 and R ₂ is a carbon number of ₂ to 20. R having an alkylene group (including a group whose side chain is substituted with an alkyl group) or a cyclohexanedimethanol group
₃ represents an ethylene, propylene or tetramethylene group. ]

The present invention will be described in detail below. The aliphatic polyester ether of the present invention comprises the above general formulas (1) and / or (2) and (3) as constitutional units, and has at least a polystyrene-reduced number average molecular weight determined by gel filtration chromatography (GPC). 30,00
It is an aliphatic polyester ether having a value of 0 or more, particularly 40,000 to 100,000. Number average molecular weight is 30,
If it is less than 000, the molding processability is deteriorated and a molded product having sufficient strength cannot be obtained.

The number average molecular weight of the structural unit represented by the general formula (1) and / or (2) is 200 to 75,
000 is preferable, and 200 to 50,000 is particularly preferable. Further, the number average molecular weight of the structural unit represented by the general formula (3) is preferably 100 to 50,000,
Particularly, 200 to 20,000 is preferable. The weight ratio of the structural units represented by the general formula (1) and / or (2) and (3) is preferably 1: 0.01 to 1: 1.5, and 1: 0. The optimum value is 0.05 to 1: 1.

The aliphatic polyester ether of the present invention can be obtained, for example, as follows. First, a diol is reacted with a dicarboxylic acid, its acid anhydride or its dialkyl ester to obtain an oligomer.

Examples of the dicarboxylic acid used in the present invention include those having a carbon number of 2 to 20, and a cycloaliphatic dicarboxylic acid is also included. Specific examples of such a dicarboxylic acid include oxalic acid, succinic acid, glutaric acid,
Adipic acid, pimelic acid, suberic acid, azelaic acid,
Sebacic acid, dodecanedioic acid, eicosanedioic acid, cyclohexanedicarboxylic acid, and their acid anhydrides and dialkyl ester compounds, such as succinic anhydride, glutaric anhydride, adipic anhydride, dimethyl succinate, dimethyl adipate and the like. A mixture can be given. Among these, it is preferable to use succinic acid, adipic acid, succinic anhydride, or the like because a polyester having a high melting point can be obtained. In addition, an aromatic dicarboxylic acid such as terephthalic acid or isophthalic acid can be used in combination as long as biodegradability is not impaired. In addition, malic acid, citric acid,
Oxycarboxylic acids such as tartaric acid, trimellitic anhydride,
A polyvalent carboxylic acid such as pyromellitic dianhydride and trimesic acid can also be used in combination.

The diol used in the present invention is 2
Examples thereof include those having an alkylene group having a carbon number of up to 20, and those in which the side chain is substituted with an alkyl group and cyclic aliphatic glycols are also included. Specific examples of such a diol include ethylene glycol, trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol and 1,10-.
Examples thereof include decanediol, propylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol and the like, and mixtures thereof. Among these, it is preferable to use ethylene glycol, 1,4-butanediol, 1,6-hexanediol or the like because a polyester having a high melting point can be obtained. Furthermore, if necessary, a polyhydric alcohol such as glycerin or pentaerythritol can be used in combination.

The charging ratio of dicarboxylic acid, its acid anhydride or its dialkyl ester, and diol is as follows:
The molar ratio is preferably 1: 1 to 1: 2.5, and 1:
1.01 to 1: 2 is more preferable, and 1: 1.0
Optimally, it is 5 to 1: 1.8.

Further, the reaction conditions for synthesizing the oligomer are preferably 120 to 250 ° C. for 1 to 10 hours, and 150 to 220 ° C. for 2 to 5 hours.
It is more preferable to carry out under atmospheric pressure, in an inert gas atmosphere, particularly under a nitrogen gas stream.

Next, in the present invention, the oligomer obtained above is deglycolized in the presence of a catalyst. Examples of the catalyst in that case include metal compounds such as titanium, germanium, antimony, magnesium, calcium, zinc, iron, zirconium, vanadium, and lithium. These are metal alkoxides, metal acetylacetonates, metal oxides, It is used in the form of a metal complex, a metal hydroxide, an organic acid salt or the like. Examples of particularly preferred catalysts include tetra-n-butyl titanate, tetraisopropyl titanate, tetraethyl titanate, titanium oxyacetylacetonate, dibutoxy diacetoacetoxy titanium, titanium acetate, tetra-n-butoxy germanium, tetraethoxy germanium, Tetraphenyl germanium, tetrabutyl germanium, germanium (IV) oxide, tributoxy antimony, triethoxy antimony, antimony trioxide, antimony acetate, zinc acetate, calcium acetylacetonate, magnesium acetylacetonate, zinc acetylacetonate, etc., You may use these catalysts 1 type (s) or 2 or more types.

The amount of catalyst used at that time is
The amount is preferably 0.01 to 5 parts by weight, and more preferably 0.05 to 2 parts by weight, per 100 parts by weight of the aliphatic polyester ether produced. Catalyst amount 0.01
If it is less than 5 parts by weight, the effect as a catalyst becomes weak, and it is difficult to obtain a polymer having a desired molecular weight. Even if it is used in an amount of more than 5 parts by weight, the effect does not change significantly,
On the contrary, the polymer produced is colored, which is not preferable. These catalysts need only be present at the time of polycondensation, and may be added immediately before deglycolization or may be added before esterification.

Further, when deglycolizing and polycondensing, a phosphorus compound can be added as a coloring preventing agent. Examples of the phosphorus compound include phosphoric acid, phosphoric anhydride, polyphosphoric acid, metaphosphoric acid, pyrophosphoric acid, phosphorous acid, hypophosphorous acid, tripolyphosphoric acid, bis (2,4-dibutylphenyl) pentaerythritol diester. Examples thereof include spirophosphorus compounds represented by phosphates and their metal salts, ammonium salts, chlorides, bromides, sulfides, esterified compounds, and the like. Particularly preferably, phosphoric acid, polyphosphoric acid, metaphosphoric acid, Examples include bis (2,4-dibutylphenyl) pentaerythritol diphosphate. These phosphorus compounds may be used alone or in combination of two or more. The amount of the phosphorus compound used in that case is preferably 0.001 to 1 part by weight, and 0.01 to 1 part by weight per 100 parts by weight of the aliphatic polyester ether produced.
0.5 parts by weight is more preferable. Further, these phosphorus compounds may be added immediately before deglycolization or may be added before esterification.

Further, when polycondensation is carried out, 0.01 to
It is preferable to perform the treatment at 200 to 280 ° C. for 1 to 10 hours under a reduced pressure of 10 mmHg, and under the reduced pressure of 0.1 to 5 mmHg, 2
It is more preferable to perform the treatment at 20 to 260 ° C. for 1 to 5 hours.

As the polyalkylene glycol used in the present invention, various polyalkylene glycols can be used, but polyethylene glycol, polypropylene glycol and polytetramethylene glycol are preferable from the viewpoint of being commercially available. Also,
Copolymers can also be used as long as they are the main components.

Further, the molecular weight of the polyalkylene glycol to be block-copolymerized is not particularly limited, but from the viewpoint of using a commercially available product, it is 100 to 50000.
0 is preferred. The amount of the polyalkylene glycol used depends on the molecular weight of the polyalkylene glycol, but the aliphatic polyester ether 100 produced
1 to 60 parts by weight per part by weight is preferable, and 5 to 40 parts by weight is optimal. The amount of polyalkylene glycol is 60
If it is more than 1 part by weight, the melting point is significantly lowered, and it becomes more difficult to become a crystalline polymer. If it is less than 1 part by weight, there is no meaning to block-copolymerize the polyalkylene glycol, and the effect of accelerating the biodegradation rate decreases Not preferable.

The polyalkylene glycol may be added at any time before the deglycol reaction, and examples thereof include a method of simultaneously charging with a dicarboxylic acid or a diol from the beginning of the reaction, and a method of charging with a catalyst or a color preventing agent immediately before the deglycol reaction. .

Since the aliphatic polyester ether produced as described above is thermoplastic and has moldability, it can be applied to various uses. For example, as a biodegradable polymer, it can be processed into a film, a fiber, a sheet or the like and used as various bottles, shopping bags, packaging materials, synthetic threads, fishing lines, fishing nets, non-woven fabrics, agricultural mulch films, and the like.

[0026]

EXAMPLES The present invention will be specifically described below with reference to examples. Each value was obtained as follows. (1) Reduced Specific Viscosity (ηsp / c) The polymer solution viscosity at a concentration of 0.5 g / deciliter was measured using an Ubbelohde viscometer, and used as a standard for the molecular weight. Chloroform was used as the solvent, and the measurement was performed at 30 ° C. (2) Melting point Using a thermal analyzer (DSC-7) manufactured by Perkin Elmer, the melting point was measured at a temperature rising rate of 20 ° C / min. (3) polystyrene-reduced number average molecular weight (Mn) obtained from GPC Using a GPC measuring device manufactured by Waters,
Waters ultrastyragel with average pore diameters of 10 ³ and 10 ⁴ Å, 1 each, 7.8mmφ × 30cm
Measurements were carried out at 35 ° C. using a long column and chloroform as the eluent. In addition, polystyrene was used as a standard.

Example 1 In a three-necked flask equipped with a stirrer, a Wigley fractionating tube and a gas introducing tube, 47.2 g (0.4 mol) of succinic acid was added.
39.7 g (0.44 mol) of 1,4-butanediol and 10 g of polyethylene glycol (molecular weight 200) (0.
(05 mol) and put in a hot water bath. 200 this bath
The temperature is raised to ℃, nitrogen is slowly flowed into the melt, and 200 ℃
At the temperature of 3 hours, the generated water and excess glycol were distilled off to obtain an oligomer.

Then, tetrabutyl titanate 0.14
g (4.0 × 10 ⁻⁴ mol) and bis (2,4-dibutylphenyl) pentaerythritol diphosphate.
Add 0.5g, keep the temperature at 220 ℃, 0.5mmH
2 hours under reduced pressure of g, 240 ° C., 0.5 mmH
A viscous polymer liquid was obtained by heating for 30 minutes under reduced pressure of g.

This polymer becomes a white polymer when cooled to room temperature (20 ° C.), ηsp / c is 1.26 (concentration 0.5 g / deciliter, 30 ° C., in chloroform), and melting point is 103 ° C. It was The number average molecular weight (Mn) in terms of polystyrene determined by GPC is 51,
It was 000. The structural unit of this polymer is R
₁ is an ethylene group, R ₂ is a butylene group, R ₃
Was an ethylene group.

Example 2 Instead of 10 g of polyethylene glycol, 10 g of polytetramethylene glycol (molecular weight 1,000) (0.
A white polymer was obtained in exactly the same manner as in Example 1 except that (01 mol) was used. Ηsp / c of this polymer was 1.22 (concentration: 0.5 g / deciliter, 30 ° C., in chloroform), and the melting point was 109 ° C. Also,
The polystyrene-reduced number average molecular weight (Mn) determined by GPC was 50,000. Further, in the constitutional unit of this polymer, R ₁ was an ethylene group, R ₂ was a butylene group, and R ₃ was a butylene group.

Example 3 20 g (0.000) of polypropylene glycol (molecular weight 2,000) was used instead of 10 g of polyethylene glycol.
A white polymer was obtained in exactly the same manner as in Example 1, except that 5 mol) was used. The ηsp / c of this polymer is 1.
31 (concentration 0.5 g / deciliter, 30 ° C. in chloroform), and the melting point was 108 ° C. Also, GP
Number average molecular weight (M
n) was 54,000. In the constitutional unit of this polymer, R ₁ was an ethylene group, R ₂ was a butylene group, and R ₃ was a propylene group.

Example 4 47.2 g (0.4 mol) of succinic acid was placed in a three-necked flask equipped with a stirrer, a Wiggle fractionating tube and a gas introducing tube.
32.3 g (0.52 mol) of ethylene glycol and 10 g (0.02 mol) of polyethylene glycol (molecular weight 400)
5 mol) and put in a hot water bath. This hot water bath is 200 ℃
The temperature was raised to 1, nitrogen was slowly flowed into the melt, and the water and excess glycol produced over a period of 3 hours at a temperature of 200 ° C. were distilled off to obtain an oligomer.

Next, 0.05 g of polyphosphoric acid and 0.15 g of tetrabutoxy germanium (4.0 × 10 ^-4 mol)
Was added, and the temperature was maintained at 220 ° C., and the mixture was heated at a reduced pressure of 0.5 mmHg for 1 hour and further at 240 ° C. and a reduced pressure of 0.5 mmHg for 1 hour to obtain a viscous polymer liquid. .

This polymer became a white polymer when cooled to room temperature (20 ° C.), ηsp / c was 1.20 (concentration 0.5 g / deciliter, 30 ° C., in chloroform), and melting point was 93 ° C. It was The number average molecular weight (Mn) in terms of polystyrene determined by GPC is 52,0.
It was 00. The constitutional unit of this polymer is
All of R ₁ , R ₂ and R ₃ were ethylene groups.

Example 5 40.0 g (0.4 mol) of succinic anhydride and 37.5 g (0) of 1,4-butanediol were placed in a three-necked flask equipped with a stirrer, a Wigley fractionating tube and a gas introducing tube. 0.42 mol), ethylene glycol 6.5 g (0.10 mol) and polyethylene glycol (molecular weight 6,000) 5 g
(8.3 × 10 ⁻³ mol) was added and immersed in a hot water bath. The temperature of this hot water bath was raised to 200 ° C., nitrogen was slowly poured into the melt, and the water and excess glycol produced at a temperature of 200 ° C. for 3 hours were distilled off to obtain an oligomer.

Then, 0.025 g of polyphosphoric acid and 0.27 g of tributoxyantimony (8.0 × 10 ⁻⁴ mol) were added, the temperature was maintained at 220 ° C., and the pressure was reduced to 0.5 mmHg for 2 hours. Further, by heating at 240 ° C. under reduced pressure of 0.5 mmHg for 1 hour, a viscous polymer liquid was obtained.

This polymer became a white polymer when cooled to room temperature (20 ° C.), ηsp / c was 1.24 (concentration 0.5 g / deciliter, 30 ° C., in chloroform), and melting point was 98 ° C. It was The number average molecular weight (Mn) in terms of polystyrene determined by GPC is 53,0.
It was 00. The constitutional unit of this polymer is R ₁
Was an ethylene group, R ₂ was an ethylene group and a butylene group, and R ₃ was an ethylene group.

Example 6 42.5 g (0.36 mol) of succinic acid, 5.8 g (0.04 mol) of adipic acid were placed in a three-necked flask equipped with a stirrer, a Wigley fractionating pipe and a gas introducing pipe. 1,4-
Butanediol 54.1 g (0.6 mol) and polypropylene glycol (molecular weight 1,000) 15 g (0.01
5 mol) and put in a hot water bath. This hot water bath is 200 ℃
The temperature was raised to 1, nitrogen was slowly flowed into the melt, and the water and excess glycol produced over a period of 3 hours at a temperature of 200 ° C. were distilled off to obtain an oligomer.

Next, 0.025 g of polyphosphoric acid and 0.16 g of dibutoxydiacetoacetoxytitanium (4.0 × 1)
0 ^-4 mol) and maintain the temperature at 220 ° C.
Under reduced pressure of mmHg for 2 hours, further 240 ° C., 0.5
A viscous polymer liquid was obtained by heating under a reduced pressure of mmHg for 1 hour.

This polymer becomes a white polymer when cooled to room temperature (20 ° C.), ηsp / c is 1.35 (concentration 0.5 g / deciliter, 30 ° C., in chloroform), and melting point is 100 ° C. It was The number average molecular weight (Mn) in terms of polystyrene determined by GPC is 55,
It was 000. The structural unit of this polymer is R
₁ was an ethylene group and a butylene group, R ₂ was a butylene group, and R ₃ was a propylene group.

Comparative Example 1 43.8 g (0.3) of dimethyl succinate was placed in a three-necked flask equipped with a stirrer, a Wiggle fractionating tube and a gas introducing tube.
Mol), 27.9 g (0.45 mol) of ethylene glycol and polyethylene glycol (molecular weight 400) 10.
5 g (0.026 mol) was added, nitrogen was passed through for 15 minutes or more, and then immersed in a hot water bath. Take this bath for 30 minutes or more 1
The temperature was raised to 80 ° C. and the temperature was kept at 180 ° C. for 2 hours to obtain an oligomer.

Next, tetraisopropoxy titanium 0.
41 g (1.4 × 10 ⁻³ mol) was added, the pressure was reduced to 1 mmHg or less over 30 minutes, and the temperature was raised to 240 ° C.
This state was maintained for 6 hours to obtain a polymer liquid.

This polymer becomes a brown polymer when cooled to room temperature (20 ° C.), ηsp / c is 0.52 (concentration 0.5 g / deciliter, 30 ° C., in chloroform), and melting point is 58 ° C. It was The number average molecular weight (Mn) in terms of polystyrene determined by GPC is 26,0.
It was 00.

Comparative Example 2 47.2 g (0.4 mol) of succinic acid was placed in a three-necked flask equipped with a stirrer, a Wigley fractionating tube and a gas introducing tube.
Then, 39.7 g (0.44 mol) of 1,4-butanediol was added and immersed in a hot water bath. Raise the temperature of this water bath to 200 ° C,
Nitrogen was slowly flowed into the melt, and the water and excess glycol produced over a period of 3 hours at a temperature of 200 ° C. were distilled off to obtain an oligomer.

Then, 0.14 g (4.0 × 10 ^-4 mol) of tetra-n-butyl titanate was added, and the temperature was adjusted to 22.
A viscous polymer liquid was obtained by heating at 0 ° C. for 1 hour under a reduced pressure of 0.5 mmHg.

This polymer became a white polymer when cooled to room temperature (20 ° C.), ηsp / c was 1.22 (concentration 0.5 g / deciliter, 30 ° C., in chloroform), and the melting point was 117 ° C. It was Further, the number average molecular weight (Mn) in terms of polystyrene determined by GPC was 56,
It was 000.

Comparative Example 3 40.0 g (0.4 mol) of succinic anhydride and 32.3 g (0.52 mol) of ethylene glycol were placed in a three-necked flask equipped with a stirrer, a Wiggle fractionation pipe and a gas introduction pipe.
, And soaked in a hot water bath. The temperature of this hot water bath was raised to 200 ° C., nitrogen was slowly flown into the melt, and the water and excess glycol that were produced at 200 ° C. for 2 hours were distilled off to obtain an oligomer.

Next, 0.1 g of polyphosphoric acid and tetra-n
-Butoxygermanium 0.15 g (4.0 × 10 ^-4 mol) was added, the temperature was kept at 220 ° C., 0.5 mmHg
Under reduced pressure of 1 hour, further 240 ℃, 0.5mmHg
A viscous polymer liquid was obtained by heating under reduced pressure for 3 hours.

This polymer became a white polymer when cooled to room temperature (20 ° C.), ηsp / c was 1.07 (concentration 0.5 g / deciliter, 30 ° C., in chloroform), and melting point was 104 ° C. It was The number average molecular weight (Mn) in terms of polystyrene determined by GPC was 52,
It was 000.

Reference Example 1 The polymers obtained in Example 4 and Comparative Examples 2 and 3 were melt-pressed using a hot press machine at a temperature 30 to 40 ° C. higher than their melting points to prepare a film having a thickness of 50 μm. Then, this film was cut into 4 cm x 4 cm, and the soil (surface layer 5-1
Implantation was performed at 0 cm), and the state of the initial, 3 months, and 6 months was examined to evaluate biodegradability. The results are shown in Table 1. In addition, the weight retention rate in the table is shown as a relative percentage with the initial (0) weight as 100.

[0051]

[Table 1]

As shown in Table 1, the aliphatic polyester ether of the present invention (Example 4) has a lower weight retention and a lower viscosity than the aliphatic polyester (Comparative Examples 2 and 3). From this, it is understood that the aliphatic polyester ether of the present invention is excellent in biodegradability.

[0053]

INDUSTRIAL APPLICABILITY Since the aliphatic polyester ether of the present invention has an excellent biodegradation rate and a molecular weight such that it can be molded, it can be used as a biodegradable polymer in various applications.

Claims (1)

[Claims] 1. An aliphatic polyester ether having the following general formulas (1) and / or (2) and (3) as constitutional units and having a number average molecular weight of at least 30,000. Embedded image [Wherein n, m, and l are integers of 2 or more, and R ₁
Is an alkylene group having 1 to 18 carbon atoms or a cyclohexylene group, R ₂ is an alkylene group having ₂ to 20 carbon atoms (including those in which the side chain is substituted with an alkyl group),
Alternatively, a cyclohexanedimethanol group and R ₃ represent an ethylene, propylene or tetramethylene group. ]