WO2018235600A1

WO2018235600A1 - Polymer composition

Info

Publication number: WO2018235600A1
Application number: PCT/JP2018/021704
Authority: WO
Inventors: 成川原; 成志吉川; 傳喜片山; 幸樹柴田
Original assignee: 東洋製罐グループホールディングス株式会社
Priority date: 2017-06-20
Filing date: 2018-06-06
Publication date: 2018-12-27
Also published as: TW201905036A; JP2020128449A

Abstract

This polymer composition contains a polymer component that is a polyoxylate having a diol-derived diol constituent unit and an oxalic acid-derived acid constituent unit. The polymer composition is characterized by containing a terminal carboxyl group sealant as a molding stabilizer in addition to the polyoxylate, and by having a 5% weight loss temperature of 300°C or less as measured by TG-DTA.

Description

Polymer composition

The present invention relates to a polymer composition comprising polyoxalate as polymer component.

The polyoxalate is a polyester comprising an acid structural unit derived from oxalic acid and a diol structural unit derived from a diol. Polyoxalate has excellent hydrolyzability, and its use in various applications is being considered. For example, in the field of agriculture, use in the form of films, sheets, trays, pots, etc. is being considered. In the environmental field, use as a water purification material or a soil purification material in the form of powder or pellet is being studied. In the field of resource mining such as shale gas, use in the form of powder, spherical particles, fibers or the like in addition to fracturing fluid, finishing fluid, etc. is being studied. Particularly in the field of resource mining, polyoxalate is an environmentally friendly biodegradable resin, and it is difficult to perform post-treatment work in wells and the like, and it is necessary to have water even in a low temperature (100 ° C. or less) environment Because it can be expected to hydrolyze with nature, studies are actively conducted.

By the way, polyoxalate is low in heat resistance and has a problem that it is easily thermally decomposed at the time of melt molding such as spinning, extrusion molding, injection molding and the like. For example, even in the case of forming means such as melt extrusion of polyoxalate in water and immediate cutting of the melt extrusion, such as under water cutting, polyoxalate has a disadvantage that the molecular weight is reduced. There is.

As a polyoxalate whose thermal decomposability has been improved, Patent Document 1 proposes a polyester polymer having a number average molecular weight of 10,000 or more in terms of polystyrene measured by GPC, and such a polyester polymer Polyoxalate is disclosed. This polyoxalate has a high thermal decomposition temperature and is excellent in heat resistance.

However, since the above polyoxalate is highly crystalline, it does not easily cause hydrolysis. For this reason, there is a problem that it is difficult to apply to applications that utilize the hydrolyzability of polyoxalate.
For example, when polyoxalate is used in the above-mentioned resource mining field, this polyoxalate is introduced into water and required to be rapidly hydrolyzed after a certain period of time, but the polyoxalate of Patent Document 1 is There is a drawback that hydrolysis does not occur easily even after a certain period of time.

The present applicant previously proposed a polyoxalate copolymer using a total of two or more of ethylene glycol and other diols as a diol in Japanese Patent Application No. 2016-035585 (Japanese Patent Laid-Open No. 201-149892). doing. Such a polyoxalate copolymer has heat resistance, and the reduction in molecular weight at the time of thermoforming is suppressed. Furthermore, if sufficient water is present even in a low temperature (100 ° C. or lower) environment such as in a well, hydrolysis starts within several days from the start of use, and hydrolysis is thereafter rapidly. Thus, the polyoxalate copolymers of the prior application also possess adequate hydrolytic properties.

However, the polyoxalate copolymer of the prior application is limited in the type of diol to be used, and the degree of freedom in designing the structure of polyoxalate is low depending on the application, use environment, etc. is necessary.

JP 09-059359 A

Therefore, an object of the present invention is a polymer composition containing polyoxalate as a polymer component, in which the reduction in molecular weight during molding of polyoxalate is effectively suppressed and the hydrolyzability of polyoxalate is maintained. To provide.

According to the invention, in a polymer composition comprising, as polymer component, a polyoxalate having a diol constituent unit derived from a diol and an acid constituent unit derived from oxalic acid,
In addition to the polyoxalate, there is provided a polymer composition comprising a terminal carboxyl group capping agent as a molding stabilizer and having a 5% weight loss temperature by TG-DTA of 300 ° C. or less.

In the polymer composition of the present invention, the following embodiments are preferred.
(1) The terminal carboxyl group capping agent is a carbodiimide compound or a polycarbodiimide.
(2) The diol is butanediol or ethylene glycol.
(3) The diol is butanediol.
(4) The 5% weight loss temperature is 220 to 300 ° C.
(5) The polymer composition according to claim 1, wherein the residual ratio represented by the following formula is 10% or less when immersed in distilled water at 90 ° C. for 1 week for hydrolysis.
Residual rate (%) = W2 (weight g after hydrolysis) / W1 (initial input amount g) × 100

According to the present invention, there is also provided a molded article obtained by thermoforming the above-mentioned polymer composition.
It is preferred that the above-mentioned molded body has a fiber or granular form.

The polymer composition of the present invention contains polyoxalate as a polymer component, and is an important feature in that a terminal carboxyl group capping agent is blended as a molding stabilizer.
That is, when polyoxalate is held for a long time at a certain temperature or higher, decomposition of the terminal carboxyl group occurs. In addition, hydrolysis occurs when high temperature polyoxalate is introduced into water due to underwater cutting and the like, and a carboxyl group is present at the end of the molecule generated by hydrolysis. Thus, degradation of the polyoxalate results in a reduction in molecular weight during molding of the polyoxalate.
However, in the present invention, as polyoxalate is shown in Comparative Examples 1 and 2 described later, when polyoxalate is kept at a temperature close to the melting point, its molecular weight decreases by 10% or more. Therefore, according to the present invention, when the terminal carboxyl group capping agent (polycarbodiimide) is blended, the reduction of the molecular weight of the polyoxalate is 6% or less, as shown in Examples 1 to 6. Be suppressed. As understood from this, in the polymer composition containing the polyoxalate of the present invention, the thermal decomposition during melt molding of the polyoxalate is effectively suppressed.

That is, in the present invention, a terminal carboxyl group capping agent is blended, and the terminal of the carboxyl group is protected by this capping agent, thermal decomposition of polyoxalate is suppressed, and further polyoxalate accompanied by hydrolysis. Chain decomposition is effectively suppressed.

In the polymer composition of the present invention, the 5% weight loss temperature by TG-DTA is in the range of 300 ° C. or less (preferably 220 to 300 ° C.). The 5% weight loss temperature is prepared by the compounding amount of the terminal carboxyl group capping agent, and when the compounding amount of the sealant is increased, the 5% weight loss temperature becomes high, and when the compounding amount is decreased, the 5% weight component is reduced. The reduced temperature is lower.

That is, in the present invention, since the amount of the terminal carboxyl group capping agent is adjusted so that the 5% weight loss temperature is in the above range, the initial hydrolysis of polyoxalate in a water-containing environment at high temperature is Although it is suppressed, once hydrolysis occurs, hydrolysis proceeds rapidly, as with normal polyoxalate. That is, at the time of molding such as under water cutting, hydrolysis is suppressed and the lowering of the molecular weight is prevented, but the obtained molded product is a molded product of polyoxalate in which the terminal carboxyl group capping agent is not blended. It will exhibit the same hydrolyzability.
For example, when the terminal carboxyl group capping agent is blended so that the 5% weight loss temperature is higher than the above range, the polyoxalate is excessively stabilized and the hydrolyzability of the polyoxalate is impaired. It will be

As described above, according to the present invention, it is possible to effectively suppress decomposition (reduction in molecular weight) at the time of molding which causes a heat history due to heating and melting and the like without impairing the hydrolyzability of polyoxalate.

The figure which shows the general | schematic structure of the reactor used for a two-step polymerization method.

<Polyoxalate>
The polyoxalate used in the present invention is a polyester having a diol constituent unit derived from a diol and an acid constituent unit derived from oxalic acid, and an esterification polymerization reaction by reacting a diol and oxalic acid, or an alkyl oxalate Obtained by a polymerization reaction involving transesterification using
This polyoxalate has an oxalate repeating unit represented by the following formula.
-(-CO-CO-O-A-O-) _n-
In the formula, n is a positive number representing the degree of polymerization, A is an organic group derived from a diol, and a plurality of organic groups A may be identical to one another or may be different from one another.

The alkyl oxalate is preferably a dialkyl oxalate, more preferably a dialkyl oxalate consisting of an alkyl group having 1 to 4 carbon atoms such as dimethyl oxalate, diethyl oxalate, propyl oxalate, dimethyl oxalate and diethyl oxalate Particularly preferred. Examples of diols include ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol, dodecanediol, neopentyl glycol, bisphenol A, cyclohexane dimethanol and the like, but it is easy to obtain appropriate hydrolyzability. Thus, linear dihydric alcohols such as ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol, dodecanediol are preferred, butanediol or ethylene glycol is more preferred, and butanediol is particularly preferred. In the range which does not impair invention, you may copolymerize except oxalic acid, and the dicarboxylic acid which has an aliphatic, an aliphatic ring and an aromatic ring, and a hydroxy acid may be copolymerized.

The polyoxalate used in the present invention may be a copolymer containing other ester units as long as it has the above-mentioned oxalate repeating unit, but preferably, 80 mol% or more of the above-mentioned oxalate repeating unit Particularly, it is preferable that 90 mol% or more is contained.

The weight average molecular weight (Mw) of the polyoxalate described above is preferably 30,000 to 200,000, more preferably 50,000 to 150,000, and still more preferably 50,000 to 100,000, from the viewpoint of facilitating acquisition of appropriate hydrolysability and molding processability. It is. Even if the molecular weight exceeds the above upper limit value, the performance is not affected at all, but since the polymerization time becomes long, there is a concern that the productivity may be lowered.

<Terminal carboxyl group capping agent>
The terminal carboxyl group capping agent used together with the above polyoxalate in the polymer composition of the present invention is a compound or polymer having a functional group which can be bonded to a carboxyl group to function as a protective group.

Examples of such a functional group include a carbodiimide compound having a carbodiimide group (-N = C = N-), an epoxy compound having an epoxy group, an oxazoline compound having an oxazoline group, a monocarboxylic acid, a monoamine, an acid anhydride Substances, monoisocyanates, mono acid halides, monoesters, monoalcohols, etc., but carbodiimide compounds are preferred because they do not form by-products and there is no concern about foaming upon addition.

As a carbodiimide compound, monocarbodiimide having one carbodiimide group in the molecule, for example, N, N'-diisopropylcarbodiimide, N, N'-di-tert-butylcarbodiimide, N- (3-dimethylaminopropyl) -N Aliphatic monocarbodiimides such as' -ethylcarbodiimide, N, N'-dicyclohexylcarbodiimide; N, N'-diphenylcarbodiimide, N, N'-di-p-tolylcarbodiimide, N, N'-bis (dimethylphenyl) carbodiimide N, N'-bis (methoxyphenyl) carbodiimide, N, N'-bis (nitrophenyl) carbodiimide, N, N'-bis (2,6-diisopropylphenyl) carbodiimide, N, N'-bis (triphenyl) Aromatic groups such as silyl) carbodiimide Carbodiimide; and the like.

Further, as the polymer having a functional group as described above, polycarbodiimides having two or more carbodiimide groups in the molecule, for example, aliphatic polycarbodiimides such as poly (4,4'-dicyclohexylmethanecarbodiimide); poly (p -Phenylene carbodiimide), poly (m-phenylene carbodiimide), poly (methyl phenylene carbodiimide), poly (diisopropyl phenylene carbodiimide), poly (methyl diisopropyl phenylene carbodiimide), poly (1, 3, 5- triisopropyl phenylene carbodiimide), poly Aromatic polycarbodiimides such as (1,3,5-triisopropylphenylene-co-1,5-diisopropylphenylene carbodiimide), poly (4,4'-diphenylmethane carbodiimide), etc. That.
Among the above polycarbodiimides, aliphatic polycarbodiimides are preferable because they can efficiently protect carboxyl groups.
Various types of polycarbodiimides such as those described above are marketed by Nisshinbo Chemical Co., Ltd. under the trade name of Carbodilite. This carbodiimide is a polymer obtained by decarboxylative condensation of diisocyanate.

In the present invention, such terminal carboxyl group capping agent is determined such that the 5% weight loss temperature (Td 5%) by TG-DTA of the polymer composition is 300 ° C. or less, more preferably 220 to 300 ° C. Be done. The higher the Td 5% value, the more stable the polyoxalate, but the lower the hydrolyzability. As already mentioned, Td5% becomes high, so that the compounding quantity of terminal carboxyl group blocking agent increases.
A polymer composition having a Td of 5% in the above-mentioned range has the adequate hydrolyzability required for polyoxalate while having sufficient stability to withstand molding.

In the present invention, the blending amount of the terminal carboxyl group capping agent for securing a value of 5% of Td as described above varies depending on the type of the sealant, the structure of polyoxalate, etc. It is 1,000 to 50,000 ppm, in particular 1,000 to 20,000 ppm, relative to polyoxalate.

<Other ingredients>
In the present invention, as long as the effect is not impaired, additives of terminal carboxyl group capping agent such as plasticizer, light stabilizer, antioxidant, UV absorber, flame retardant, colorant, pigment, filler, filler And mold release agents, antistatic agents, perfumes, lubricants, foaming agents, antibacterial and antifungal agents, nucleation agents, layered borates, crosslinkers, enzymes and the like. In addition, biodegradable resin compositions other than polyoxalate, for example, aliphatic polyester, polyvinyl alcohol, and celluloses may be blended together as required.

<Production of Polymer Composition>
The polymer composition of the present invention is subjected to an esterification polymerization reaction such as dehydration reaction or transesterification reaction by a known method to polymerize the polyoxalate, and the terminal carboxyl group capping agent is stirred in the obtained polyoxalate. It is manufactured by mixing.

For the esterification polymerization reaction to obtain polyoxalate, known catalysts can be used, if necessary. Examples of known catalysts include titanium alkoxides such as titanium tetrabutoxide, antimony compounds such as antimony trioxide, and tin compounds such as dibutyltin oxide and butyltin dilaurate, but in addition to this, P, Ge, Examples thereof include Zn, Fe, Mn, Co, Zr, V and compounds of various rare earth metals.

The esterification polymerization reaction may be carried out without a solvent, but an organic solvent may be suitably used. Organic solvents include aromatic hydrocarbon-based organic solvents such as benzene, toluene and xylene; aliphatic hydrocarbon-based organic solvents such as pentane, hexane, cyclohexane, heptane, decalin and tetralin; ether-based organic solvents such as ethyl ether and tetrahydrofuran Solvents; Chlorinated hydrocarbon-based organic solvents such as chloroform, chlorobenzene, carbon tetrachloride, etc .;

As a specific polymerization method of polyoxalate, for example, there is a method of proceeding an esterification polymerization reaction in two steps of normal pressure polymerization and reduced pressure polymerization using a diol and an alkyl oxalate. Such a two-step polymerization method can be carried out without using an organic solvent and in the absence of a solvent. The implementation without solvent is advantageous in terms of production cost and the like.

The two-stage polymerization method may be carried out using a batch-type polymerization reactor shown in FIG. Referring to FIG. 1, the polymerization reactor 1 is provided with a stirrer 3 and a distillation pipe 5. The distillation pipe 5 has a top A, and also has a reflux portion 5a in the region from the polymerization reactor 1 to the top A and a distillation 5b downstream of the top A. The distillation section 5b is provided with a cooling pipe 5c such as a heat exchanger so that the liquid to be distilled is condensed and discharged quickly. A heating pipe or a cooling pipe may be appropriately attached to the reflux portion 5a so that the temperature of the top A can be adjusted.

The reaction liquid 10 (alkyl oxalate, diol and optionally used catalyst and organic solvent) is supplied into the polymerization reactor 1, and alcohol, unreacted diol, oligomer and the like by-produced in the esterification polymerization reaction are distilled off. The distillation portion 5 b is distilled off as a distillate 15 through the reflux portion 5 a of the last tube 5. The two-step polymerization method is carried out while adjusting the distillation conditions.

The amount of diol charged in the reaction solution is 0.8 to 1.2 moles, preferably 1.0 to 1.2 moles, per mole of alkyl oxalate, from the viewpoint of rapidly advancing an atmospheric pressure polymerization reaction.

1. Atmospheric pressure polymerization Atmospheric pressure polymerization is carried out by displacing the inside of the polymerization reactor 1 to a nitrogen gas atmosphere, charging the reaction solution and heating it to a range of 110 to 200 ° C. while stirring, whereby the low polymerization degree The polyoxalate of If the reaction temperature is too high, the low polymerization degree polyoxalate to be produced may be decomposed. If the reaction temperature is too low, the reaction rate is slow, and there is a possibility that the polymerization can not be carried out effectively.
When the distillation of the alcohol stops, the normal pressure polymerization is stopped and the next reduced pressure polymerization is performed.

2. Low pressure polymerization The low pressure polymerization is to maintain the reaction liquid 10 containing low polymerization degree polyoxalate generated by atmospheric pressure polymerization at 180 to 210 ° C. while maintaining the pressure in the polymerization reactor 1 at 0.1 to 1 kPa under reduced pressure. It is done by The polymerization is allowed to proceed further while removing the diol remaining in the reaction liquid 10 by the reduced pressure polymerization, to obtain a further polymerized polyoxalate.

In the low pressure polymerization, when the temperature of the reaction liquid is too low, the high molecular weight formation is insufficient, and the hydrolyzability of the resulting polyoxalate becomes excessively large, and, for example, when mixed with water, it hydrolyzes at once. When the reaction solution temperature is too high, decomposition of the formed polyoxalate occurs.

In the reduced pressure polymerization step, in order to accelerate the removal of the residual diol, it is preferable to keep the reflux portion 5a of the distillation pipe 5 at 90 to 140 ° C.

The reduced pressure polymerization step may be ended when removal of the residual diol is stopped. The termination of removal of the residual diol can be confirmed by monitoring the temperature at the top of the head A of the distillation pipe 5, for example.

By the reduced pressure polymerization following the normal pressure polymerization, the content of impurities such as by-product alcohol and unreacted diol is suppressed, and a polyoxalate having a higher molecular weight than at the time of normal pressure polymerization can be obtained.

As a matter of course, the above description does not limit the polymerization method of polyoxalate in the present invention, and the polymerization may be performed by other methods.

Subsequently, the terminal carboxyl group capping agent is charged into the molten polyoxalate, and the mixture is stirred and mixed. The stirring and mixing may be performed according to known conditions and means, but when stirring and mixing is performed under a reduced pressure of 10 kPa or more and less than 1000 kPa, impurities such as residual diol and by-product alcohol can be removed. ,preferable.

In the stirring and mixing, the terminal carboxyl group capping agent is uniformly mixed in the polyoxalate, whereby a part of the capping agent reacts with the terminal carboxyl group of the polyoxalate to seal the carboxyl group. Be done. The mixing time is generally about 0.5 to 3 hours.
The capping of the terminal carboxyl group by the polyoxalate can be confirmed by the decrease in the acid value of the polyoxalate, the decrease in initial hydrolyzability, and the like.
The terminal carboxyl group capping agent can also be mixed with the polyoxalate as a liquid dissolved or dispersed in a blend, a solvent, or the like, which is melt mixed with another polymer.

In addition, since polyoxalate may be reduced in molecular weight in the stirring and mixing step of the carboxyl group-binding compound, in that case, it is preferable to polymerize the polyoxalate in advance assuming the lowering of molecular weight in the stirring and mixing step. .

The terminal carboxyl group capping agent can also be mixed with the polyoxalate in the kneading section of the extruder. For example, the polio chelate and the terminal carboxyl group capping agent may be simultaneously supplied from the hopper to the kneading section of the extruder, or the polyoxalate is first supplied from the hopper and melted, and the terminal carboxyl is added to the middle of the extruder A base sealant may be supplied.

The polymer composition of the present invention has heat resistance, and hydrolysis in water is suppressed if it is a short time as in a molding process. This means that the polymer composition is held at 150 ° C. for 5 minutes, and the weight average molecular weight when immersed in water at 25 ° C. for 1 minute is measured, and the molecular weight retention is calculated, the polymer composition of the present invention In this case, it is clear from showing 90% or more, especially 92% or more.

Furthermore, the polymer composition of the present invention has moderate hydrolyzability after molding, similar to known polyoxalate. The appropriate hydrolyzability can be confirmed from the hydrolysis behavior of the polymer composition of the present invention even if the hydrolysis behavior of the molded body is not confirmed. That is, a sample obtained by pulverizing the polymer composition is put into distilled water at 90 ° C. and hydrolyzed for one week, and then the weight (weight after hydrolysis) of the remaining sample is measured, and the residual ratio is determined by the following equation. The residual ratio of the polymer composition of the present invention is 10% or less, 8% or less in a preferred embodiment, and 5% or less in a particularly preferred embodiment.
Residual rate (%) = W2 (weight g after hydrolysis) / W1 (initial input amount g) × 100
Thus, since the polymer composition of the present invention shows a low value within 1 week before molding, when it has been in contact with a sufficient amount of water several days after molding, It is self-evident that hydrolysis proceeds rapidly.

The polymer composition of the present invention having the characteristics as described above is applied to applications such as extrusion molding, injection molding, and the like which are required to be hydrolyzable as a thermoformed product obtained by molding the melt into a predetermined shape. Be done. For example, those thermoformed in the form of fibers or pellets are suitably applied to mining dispersions represented by fracturing fluids and finishing fluids.
Also, in order to make use of the hydrolyzability of the polymer composition (polyoxalate composition), it is suitably formed into a film, sheet, tray, container, etc. form by thermoforming mixed with other polymers, It is degradable and can be used as an environmentally friendly molding.

For example, when fibers of 0.1 to 5 cm in length obtained from the polymer composition of the present invention are dispersed in water to prepare a dispersion for drilling and the dispersion for drilling is pressed into the ground, such fibrous The shaped bodies are hydrolyzed after a suitable period of time at a temperature of 40-80.degree. Therefore, it is possible to mine underground resources such as shale gas by hydraulic fracturing using such a dispersion as a fracturing fluid.

The polymer compositions of the present invention are illustrated by the following examples. In addition, various measurements were performed by the following methods.

<Measurement of Molecular Weight of Polybutylene Oxalate>
Device: gel permeation chromatograph GPC
Detector: Differential Refractive Index Detector RI
Column: SuperMultipore HZ-M (two)
Solvent: chloroform flow rate: 0.5 mL / min
Column temperature: 40 ° C
Sample preparation: 3 mL of a solvent was added to about 10 mg of a sample and left at room temperature. After confirmation of dissolution by visual observation, the solution was filtered through a 0.45 μm filter. The standard used polystyrene.

<Measurement of Molecular Weight of Polyethylene Oxalate>
Device: gel permeation chromatograph GPC
Detector: Differential Refractive Index Detector RI
Column: Shodex HFIP-LG (one), HFIP-806M (two) (Showa Denko)
Solvent: Hexafluoroisopropanol (5 mM sodium trifluoroacetate added)
Flow rate: 0.5mL / min
Column temperature: 40 ° C
Sample preparation: 5 mL of a solvent was added to about 1.5 mg of a sample and gently stirred at room temperature (sample concentration about 0.03%). After confirmation of dissolution by visual observation, the solution was filtered through a 0.45 μm filter. The standard used polymethyl methacrylate.

<5% weight loss temperature (Td 5%)>
Device: TG / DTA7220 manufactured by Hitachi High-Tech Science Co., Ltd.
Sample preparation: sample amount 5 to 10 mg
Measurement conditions: Measured in a range of 40 to 300 ° C. at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere.
The temperature at which 5% weight decreased relative to the initial weight was taken as Td 5%.

<Measurement of residual rate>
In a 50 ml vial, 300 mg of a sample passed through a filter with 16 mesh openings and 20 ml of distilled water were added and hydrolyzed in an electric oven at 90 ° C. for 1 week.
Thereafter, the supernatant was removed and dried in an electric oven at 80 ° C. for 2 hours or more, the amount of remaining sample was measured, and the remaining rate was calculated based on the following equation.
Residual rate (%) = W2 (remaining sample amount mg) / W1 (initial sample amount mg) × 100

<Measurement of molecular weight retention>
100 mg of the sample was held for 5 minutes in an electric oven at 150 ° C. and immersed in water at a temperature of 25 ° C. for 1 minute. The sample was then removed and dried in an 80 ° C. electric oven for 2 hours. The molecular weight of the sample after drying was measured in the same manner as the above-described method of measuring the molecular weight, and the residual ratio was calculated based on the following equation.
Molecular weight retention (%)
= Mw 2 (weight average molecular weight after treatment) / Mw 1 (weight average molecular weight before treatment)

Example 1
The following polycarbodiimide was prepared as a terminal carboxyl group capping agent.
Nisshinbo Chemical Co., Ltd. Carbodilight HMV-15CA;
Softening temperature 70 ° C, 5% weight loss temperature 350 ° C.
Dibutyl oxalate 354 g (3 mol), 1,4-butanediol 270 g (3 mol), dibutyltin oxide 0 in a 1 L separable flask equipped with a mantle heater, liquid temperature thermometer, stirrer, nitrogen inlet tube and distillation column The solution temperature in the flask was heated to 120 ° C. under nitrogen flow to carry out atmospheric pressure polymerization. After distillation of methanol started, the liquid temperature was gradually raised to 150 ° C., and polymerization was carried out under normal pressure. Finally, 72 ml of distillate was obtained.
The temperature of the liquid in the flask was raised stepwise to 200 ° C., and polymerization was carried out under reduced pressure at a reduced pressure of 0.1 to 0.8 kPa for 5 hours. Thereafter, the pressure was returned to normal pressure, 0.35 g of carbodilite (polycarbodiimide was 0.1% by weight with respect to the polymer yield) was added, and stirring was carried out at a reduced pressure of 10 kPa or more for 1 hour to obtain polymer 1.

Example 2
Polymer 2 was obtained in the same manner as in Example 1 except that the amount of carbodilite added was changed to 1.75 g (0.5% by weight).

Example 3
Polymer 3 was obtained in the same manner as in Example 1 except that the amount of carbodilite added was changed to 3.5 g (1.0% by weight).

Example 4
Polymer 4 was obtained in the same manner as in Example 1 except that the amount of carbodilite added was changed to 17.5 g (5.0% by weight).

Example 5
Polymer 5 was obtained in the same manner as in Example 1 except that the amount of carbodilite added was changed to 35 g (10.0% by weight).

Example 6
295 g (2.5 mol) of dimethyl oxalate, 171 g (2.76 mol) of ethylene glycol, 0 g of dibutyl tin oxide in a 1 L separable flask equipped with a mantle heater, liquid temperature thermometer, stirrer, nitrogen inlet tube and distillation column The solution temperature in the flask was gradually raised to 180 ° C. under a nitrogen stream, and polymerization was carried out under normal pressure.
Thereafter, the liquid temperature in the flask was raised to 190 ° C., and polymerization was performed under reduced pressure at a reduced pressure of 0.1 to 0.8 kPa for 6 hours. Thereafter, the pressure was returned to normal pressure, 2.5 g of carbodilite (polycarbodiimide was 1.0% by weight with respect to the polymer yield) was added, and stirring was carried out at a reduced pressure of 10 kPa or more for 1 hour to obtain polymer 6.

Comparative Example 1
Polymer 7 was obtained in the same manner as in Example 1 except that carbodilite was not used. That is, atmospheric pressure polymerization and reduced pressure polymerization were performed in the same manner as in Example 1 to obtain polymer 7.

Comparative Example 2
Polymer 8 was obtained in the same manner as in Example 6, except that carbodilite was not used. That is, atmospheric pressure polymerization and reduced pressure polymerization were performed in the same manner as in Example 6, to obtain polymer 8.

<Evaluation test>
Various physical properties of the obtained polymer were measured. The results are shown in Table 1.

1: Polymerization reactor 3: Stirrer 5: Distillation pipe A: Head top 5a: Reflux part 5b: Distillation part 5c: Cooling pipe 10: Reaction liquid 15: Distillation liquid

Claims

A polymer composition comprising, as a polymer component, a polyoxalate having a diol constituent unit derived from a diol and an acid constituent unit derived from oxalic acid,
A polymer composition comprising a terminal carboxyl group capping agent as a molding stabilizer together with the polyoxalate, and having a 5% weight loss temperature by TG-DTA of 300 ° C. or less.
The polymer composition according to claim 1, wherein the terminal carboxyl group capping agent is a compound or polymer having a carbodiimide group in the molecule.
The polymer composition according to claim 1, wherein the diol is butanediol or ethylene glycol.
The polymer composition according to claim 3, wherein the diol is butanediol.
The polymer composition according to claim 1, wherein the 5% weight loss temperature is from 220 to 300 属 C.
The polymer composition according to claim 1, wherein the residual ratio represented by the following formula is 10% or less when immersed in distilled water at 90 ° C for 1 week for hydrolysis.
Residual rate (%) = W2 (weight g after hydrolysis) / W1 (initial input amount g) × 100
The molded object obtained by thermoforming the polymer composition of Claim 1.