JP4691934B2 - High molecular weight polyoxalate resin and method for producing the same - Google Patents

Description

  The present invention relates to a high molecular weight polyoxalate resin using a dialkyl oxalate and an aliphatic diol as raw materials and a method for producing the same.

  Methods for producing polyoxalates from dialkyl oxalates and aliphatic diols have been known, but most of the resulting polyoxalate resins have low molecular weight and cannot be melt processed. Mechanical properties of molded products Due to problems such as inferiority, there was almost no practical value.

  For example, in (1) Non-patent Document 1, polytrimethylene oxalate having an average molecular weight of about 2000 is obtained as its high molecular weight fraction by preparing an ester by heating diethyl oxalate and trimethylene glycol and then fractionally crystallizing the ester. Have been reported. Similarly, it has been reported that polyhexamethylene oxalate having an average molecular weight of about 1100 was obtained from diethyl oxalate and 1,6-hexanediol. However, the obtained polyoxalate has a low molecular weight and should be a low molecular weight oligomer rather than a polymer, and the production and physical properties of molded articles have not been reported. Moreover, the usage-amount of the oxalic acid diester and diol was not described.

  (2) In Patent Document 1, diethyl oxalate (0.02 mol) and trans-1,4-cyclohexanedimethanol (0.022 mol) are heated at 180 to 190 ° C. in the presence of titanium tetrabutoxide, and further 220 ° C. The polycyclohexylene dimethylene oxalate having a melting point of 205 to 210 ° C. and an intrinsic viscosity of 0.75 was obtained by reducing the pressure to 1 mmHg (133 Pa). However, in order to increase the molecular weight by deglycolization reaction, it is necessary to polymerize for a long time under high temperature and high vacuum, so this polyoxalate can dramatically increase the molecular weight under polymerization conditions near the melting point. It was unthinkable. Moreover, the use ratio of the dialkyl oxalate and the aliphatic diol was that the aliphatic diol was excessive with respect to the dialkyl oxalate.

  (3) In Non-Patent Document 2, a prepolymer is prepared by charging 1.25 mol of trans-1,4-cyclohexanedimethanol with respect to 1 mol of diethyl oxalate, and then solid-phase polymerization at a temperature below the melting point of the polymer. By doing so, it was reported that polycyclohexylene dimethylene oxalate having an intrinsic viscosity of 0.77 was obtained. However, as in the case of Patent Document 2, this polyoxalate is not considered to have achieved a dramatic increase in molecular weight under polymerization conditions below the melting point, and no physical properties of the molded article have been reported. It was. Moreover, the use ratio of the dialkyl oxalate and the aliphatic diol was that the aliphatic diol was excessive with respect to the dialkyl oxalate.

  (4) In Non-Patent Document 3, after heating diethyl oxalate and 1,4-butanediol at 90 to 120 ° C. in the presence of tin dioctylate, 0.1 to 0.5 Torr (13. It has been reported that polytetramethylene oxalate having a degree of polymerization of 9 (average molecular weight of 1300) was obtained by reducing the pressure to 3 to 66.5 Pa). Similarly, it has been reported that polybutyne oxalate having a degree of polymerization of 32 (average molecular weight 4500) was obtained from diethyl oxalate and 2-butyne-1,4-diol. However, the obtained polyoxalate is a low molecular weight oligomer rather than a polymer, and the production and physical properties of molded articles have not been reported. Moreover, the usage-amount of the dialkyl oxalate and the aliphatic diol was equimolar.

  (5) In Patent Document 2, produced from oxalic acid or a reactive derivative of oxalic acid (specifically dimethyl oxalate) and an aliphatic diol having 2 to 12 carbon atoms (1,6-hexanediol, etc.), A polyoxalate (oxalic acid oligoester) having excellent biodegradability having hydroxyl groups at both ends in a number average molecular weight range of 1500 to 15000 is disclosed. However, the resulting polyoxalate had a low molecular weight, was not melt processable or very difficult, and had very low mechanical strength. The proportion of dialkyl oxalate and aliphatic diol used was that the glycol component (aliphatic diol) was excessive with respect to the acid component (dialkyl oxalate).

On the other hand, in recent years, polyoxalate which is considered to have a high molecular weight has been known. However, a specific method for producing a high molecular weight polyoxalate resin has been hardly known. Even when a high molecular weight resin is obtained, the polyoxalate resin is not a polymer having a high molecular weight from dialkyl oxalate and an aliphatic diol. It is based on ring-opening polymerization of cyclic oxalate monomers, and it is difficult to mold into molded products (films, fibers, etc.) with satisfactory physical properties by general melt processing methods, or carboxyl groups at the end of the polymer The effect of this was not negligible, and spontaneous decomposition occurred or was brittle due to the action of the carboxyl group.

For example, (6) Patent Document 3 discloses a high molecular weight aliphatic polyester having a number average molecular weight of greater than 70000 and less than or equal to 1000000, and oxalic acid is included in the dicarboxylic acid (or its ester or acid anhydride) used as a raw material. It was. Further, either one of the dicarboxylic acid and the diol was used in excess, and the resulting high molecular weight aliphatic polyester had an excess component or both functional groups at the terminal. However, there is no specific disclosure of a method for producing a high molecular weight polyoxalate using dialkyl oxalate and an aliphatic diol as raw materials, and there is no disclosure of the resulting polyoxalate. In fact, according to the study by the present inventors, it was difficult to obtain a high molecular weight polyoxalate resin only by changing the ratio of dialkyl oxalate and aliphatic diol.

  (7) Patent Document 4 discloses polyethylene oxalate, a molded product thereof, and a production method thereof. Although this polyethylene oxalate is considered to have a certain degree of high molecular weight, it is not made from dialkyl oxalate and aliphatic diol as raw materials. Cyclic ethylene obtained by depolymerizing ethylene oxalate oligomers It was produced by ring-opening polymerization of an oxalate monomer. Further, this polyethylene oxalate is said to exhibit excellent heat resistance, but the molded product obtained by melt processing has a small elongation and is brittle.

Note that (8) Patent Document 5 discloses a polyoxalate using oxalic acid and glycol as raw materials and a method for producing the same. However, although this polyoxalate is considered to have a certain degree of high molecular weight, it is not made from dialkyl oxalate and an aliphatic diol as raw materials, and is charged with an excessive amount of glycol. The influence of the carboxyl group at the end could not be ignored, and spontaneous decomposition occurred due to the action of the carboxyl group, or it was brittle.

J. et al. Am. Chem. Soc. , 52, 3292 (1930) J. et al. Polym. Sci. : Part A, 2, 2115 (1964) J. et al. Polym. Sci. , Polym. Chem. Ed. , 28, 1361 (1990) U.S. Pat. No. 2,901,466 JP 2002-145691 A JP-A-8-48756 JP-A-9-316181 JP-A-9-59359

  An object of the present invention is to provide a high molecular weight polyoxalate resin using a dialkyl oxalate such as dimethyl oxalate and an aliphatic diol as raw materials, and a method for producing the same. Another object of the present invention is to provide a high molecular weight polyoxalate resin that can be molded by a general melt processing method and that can provide a molded product having sufficient mechanical properties.

  As a result of intensive studies to solve the above problems, the inventors of the present invention used dialkyl oxalate in excess with respect to the aliphatic diol and controlled the water concentration in the raw material to dialkyl oxalate and aliphatic diol. As a result of the polycondensation reaction, a high molecular weight polyoxalate resin that can be melt-molded was found to be obtained from dialkyl oxalate and an aliphatic diol, and the present invention was completed.

That is, the subject of this invention is solved by the following invention.
1) A high molecular weight polyoxalate resin composed of a polyoxalate having one of an alkoxy group, a hydroxyl group and a formate group represented by the following chemical formula. (In the formula, A represents an alkylene group having 3 to 12 carbon atoms in the main chain, which may contain a branched structure or an alicyclic structure, and n is a positive integer representing the degree of polymerization. , X represents H-, ROCOCO-, or OHC-, and when X is H-, Y represents -OR, -OAOH, or -OAOCHO, and X represents ROCOCO- or OHC-. , Y represents —OR or —OAOCHO, and R represents an alkyl group.)

2) The high molecular weight polyoxalate resin according to 1 above, which satisfies a relationship of 0.1 ≦ ([OR] + [OCHO]) / ([OH] + [OR] + [OCHO]) ≦ 1.0. (However, [OR] represents the concentration of the terminal alkoxy group of polyoxalate, [OCHO] represents the concentration of terminal formate group of polyoxalate, and [OH] represents the concentration of terminal hydroxyl group of polyoxalate.)

3) The high molecular weight polyoxalate resin according to 1 or 2 above, which has a number average molecular weight of 20,000 to 100,000.

4) Polyoxalate is a polycondensation reaction in which the ratio of dialkyl oxalate and aliphatic diol is within the range of 0.5 ≦ OL / OX <1, and the water concentration in the raw material is controlled to less than 2000 ppm. The high molecular weight polyoxalate resin according to any one of claims 1 to 3, which is a product of a condensation reaction. (However, OX represents the number of moles of dialkyl oxalate, and OL represents the number of moles of aliphatic diol.)

5) The high molecular weight polyoxalate resin according to any one of 1 to 4 above, wherein R is a methyl group.

6) The use ratio of dialkyl oxalate and aliphatic diol is in the range of 0.5 ≦ OL / OX <1, and the water concentration in the raw material is controlled to less than 2000 ppm, so that dialkyl oxalate and aliphatic diol are 2. The method for producing a high molecular weight polyoxalate resin according to 1 above, wherein a polyoxalate is produced by a condensation reaction. (However, OX and OL are the same as described above.)

7) The method for producing a high molecular weight polyoxalate resin as described in 6 above, wherein the water concentration in the raw material is controlled to 10 to 2000 ppm.

According to the present invention, a high molecular weight polyoxalate resin can be provided for the first time using a dialkyl oxalate and an aliphatic diol as raw materials. That is, a high molecular weight (having a practically high molecular weight) polyoxalate resin that can be expected to be used as a biodegradable material has heretofore been difficult to produce from dialkyl oxalate and aliphatic diol. The present invention makes it possible for the first time to produce a high molecular weight polyoxalate resin by using dialkyl oxalate as a source of oxalic acid so that the resin can be provided.
Since the high molecular weight polyoxalate resin obtained in the present invention can be molded by a general melt processing method applied to ordinary thermoplastics, sheets, films, tubes, fibers, injection molded articles, foams For example, it is possible to produce a molded article having sufficient mechanical properties that can be used in a wide range of fields.

Hereinafter, the present invention will be described in more detail.
As the dialkyl oxalate used in the present invention, oxalic acid having an alkyl group having 1 to 4 carbon atoms (corresponding to R in the above chemical formula) such as dimethyl oxalate, diethyl oxalate, propyl oxalate, dibutyl oxalate and the like. Dialkyl is preferred, with dimethyl oxalate being particularly preferred. In addition, the dialkyl oxalate may contain a part of an aromatic dicarboxylic acid ester such as dimethyl terephthalate or a carbonate ester such as dialkyl carbonate as desired to increase the heat resistance of the polyoxalate resin. However, the amount of these used is preferably within a range that does not impair the biodegradability of the polyoxalate resin. For example, it is less than 50 mol% of the dialkyl oxalate. It is not desirable to disappear.

  The aliphatic diol unit of the high molecular weight polyoxalate resin obtained in the present invention is defined by the alkylene group A of the above chemical formula. If the carbon chain of the alkylene group A is too short, depolymerization occurs during polymerization and a cyclic product is easily produced as a by-product, which is not preferable for obtaining a high molecular weight polyoxalate resin. The resulting polyoxalate resin is also excellent in heat resistance, but is hard and brittle. If the carbon chain of the alkylene group A is too long, the resulting polyoxalate resin becomes hydrophobic, the melting point and the crystallization temperature are lowered, and the use is limited, which is not preferable. Accordingly, the alkylene group A of the chemical formula is preferably one having 3 to 12 carbon atoms in the main chain. The alkylene group A may have an even or odd number of carbon atoms in the main chain, and is not limited to a straight chain structure but may include a branched structure or an alicyclic structure. Since the structure of the aliphatic diol unit significantly affects the melting point and crystallization speed of the polyoxalate resin, an appropriate aliphatic diol is selected according to the melt processing conditions or the use temperature of the molded product.

  Examples of the aliphatic diol used in the present invention include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, , 8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, neopentyl glycol, trans (or cis) -1,4-cyclohexanedi Methanol, 2,4-diethyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-ethyl-2-butyl-1,3-propanediol, 2,2,4-trimethyl-1 , 3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, etc. Like the body manner. Among these aliphatic diols, 1,6-hexanediol and trans (or cis) -1,4-cyclohexanedimethanol are preferably used. Two or more types of aliphatic diols may be contained in the polyoxalate.

  If necessary, the aliphatic diol may contain a part of a polyhydric alcohol compound (excluding the aliphatic diol) for the purpose of improving the melt processability of the polyoxalate resin or the mechanical properties of the molded product. May be. Examples of such polyhydric alcohol compounds include glycerol and 1,2,6-hexanetriol. However, the ratio of the polyhydric alcohol compound used is preferably in a range that does not cause gelation during polymerization or melt processing, and for example, it is preferably 30 mol% or less, particularly 10 mol% or less of the aliphatic diol. Too much polyhydric alcohol compound is not preferable because it may cause gelation during polymerization or melt processing as described above.

  Furthermore, the aliphatic diol may partially contain an aromatic diol as desired, for example, to increase the heat resistance of the polyoxalate resin. Examples of such aromatic diols include bisphenol A, p-xylylene glycol, and hydroquinone. However, the use ratio of the aromatic diol is preferably in a range where the melting point becomes high and the melt molding temperature range is not narrowed, for example, less than 50 mol% of the aliphatic diol. Too much aromatic diol is not preferable because the melting point becomes high as described above and the melt molding temperature range may be narrowed.

  In the method for producing a high molecular weight polyoxalate resin of the present invention in which a dialkyl oxalate and an aliphatic diol are subjected to a polycondensation reaction, it is necessary to use dialkyl oxalate in excess relative to the aliphatic diol. The ratio of use of dialkyl oxalate and aliphatic diol (feeding molar ratio) is in the range of 0.5 ≦ OL / OX <1, where OX is the number of moles of dialkyl oxalate and OL is the number of moles of aliphatic diol. Among them, the range of 0.6 ≦ OL / OX <1, more preferably 0.7 ≦ OL / OX <1, and particularly preferably 0.8 ≦ OL / OX <1 is preferable. In this invention, polyoxalate can be made high molecular weight by using dialkyl oxalate excessively in this way. If the dialkyl oxalate is excessive, a high vacuum and a large amount of heat energy are required to distill the dialkyl oxalate out of the system, so that it is industrially preferably within the above range.

  Moreover, in the manufacturing method of the high molecular weight polyoxalate resin of this invention, it is necessary to control the water concentration in a raw material (after-mentioned) to less than 2000 ppm. That is, the water concentration in the reaction raw material is controlled to less than 2000 ppm, preferably 10 to 2000 ppm. A moisture concentration of 2000 ppm or more is not preferable because the formation of a formate group results in too much clogging at the end and it is difficult for high molecular weight to occur. Thus, in the present invention, in the present invention, the polyoxalate can be increased in molecular weight by further controlling the water concentration.

  The high molecular weight polyoxalate resin of the present invention comprises a polyoxalate represented by the above chemical formula, and has one of an alkyl group, a hydroxyl group and a formate group at the terminal. That is, the high molecular weight polyoxalate resin of the present invention has a repeating unit of —O—A—O—CO—CO—, the end groups are as follows, and the number average molecular weight is preferably in the range described below. It is. However, A and R are the same as described above.

i) When the terminal group bonded to the molecular terminal on the ether group (-O-) side of the repeating unit is H-: The terminal group bonded to the molecular terminal on the other carbonyl group (-CO-) side is -OR, -OAOH or -OAOCHO.
Ii) When the terminal group bonded to the molecular terminal on the ether group (-O-) side of the repeating unit is ROCOCO- or OHC-: The terminal group bonded to the molecular terminal on the other carbonyl group (-CO-) side is -OR or -OAOCHO.

In the high molecular weight polyoxalate resin of the present invention, the terminal hydroxyl group concentration [OH], the terminal alkyl oxalate group concentration [OR], and the terminal formate group concentration [OCHO] expressed in units of eq / g are 0. 0.1 ≦ ([OR] + [OCHO]) / ([OH] + [OR] + [OCHO]) ≦ 1.0, and further 0.15 ≦ ([OR] + [OCHO]) / ( [OH] + [OR] + [OCHO]) ≦ 1.0 is more preferable in terms of color tone.

Furthermore, the high molecular weight polyoxalate resin of the present invention satisfies both the mechanical strength of the molded product and the viscosity at the time of melt molding, so that the number average molecular weight (M _n ) is in the range of 20,000 to 100,000. Although it is preferable, it is more preferably in the range of 25,000 to 800,000, further 25,000 to 75,000, particularly 30000 to 70000. When _Mn is less than 20000, the mechanical strength of the molded product is low, and when it exceeds 100,000, the melt viscosity becomes high and it is difficult to perform the molding process. “N” is a positive integer representing the degree of polymerization and is a numerical value satisfying the number average molecular weight.

  The high molecular weight polyoxalate resin of the present invention can be obtained by subjecting a dialkyl oxalate (preferably dimethyl oxalate) and an aliphatic diol to a batch or continuous polycondensation reaction (preferably melt polymerization). Specifically, it is preferable to carry out in the order of (I) pre-polycondensation step and (II) post-polycondensation step as shown by the following operations.

(I) Prepolycondensation step: Dialkyl oxalate and aliphatic diol are charged into a reactor, and after the inside of the reactor is purged with nitrogen, the temperature is gradually raised so as not to cause bumping while stirring and / or nitrogen bubbling. Although the reaction pressure may be normal pressure, the reaction temperature is preferably controlled so that the final temperature reaches 120 to 230 ° C, more preferably 130 to 200 ° C. As the reaction proceeds, alcohol (such as methanol) produced in the reaction solution is included.

  In the present invention, in order to obtain a high molecular weight polyoxalate, it is necessary to control the water concentration in the raw material to less than 2000 ppm as described above in the polycondensation reaction. The moisture is controlled by, for example, dehydrating and / or drying the reaction raw material (especially the dialkyl oxalate and the aliphatic diol) by a known method before charging the reactor, and after the charging, the inside of the reactor is purged with nitrogen. That's fine. In addition to the dialkyl oxalate and the aliphatic diol, this reaction raw material contains a catalyst. The dialkyl oxalate may contain a catalyst (aromatic dicarboxylic acid ester and carbonate ester), and the aliphatic diol contains it. What may be contained (polyhydric alcohol compound, aromatic diol) is also included.

  The charge ratio of dialkyl oxalate and aliphatic diol in the pre-polycondensation step may be such that the aliphatic diol is less than 1 mol to 0.50 mol or less per 1 mol of dialkyl oxalate, as described above. Preferably, it is less than 1 mol to 0.60 mol or less, more preferably less than 1 mol to 0.70 mol or less, particularly preferably less than 1 mol to 0.80 mol or less.

  In the polycondensation reaction, a catalyst can be used as necessary for the purpose of promoting the reaction. As such a catalyst, compounds such as P, Ti, Ge, Zn, Fe, Sn, Mn, Co, Zr, V, Ir, La, Ce, Li, Ca, and Hf are preferable. In particular, organic titanium compounds and organotin compounds are preferable. For example, titanium alkoxide (titanium tetrabutoxide, titanium tetraisopropoxide, etc.), distanoxane compound (1-hydroxy-3-isothiocyanate-1,1,3,3-tetra) Butyl distanoxane, etc.), tin acetate, dibutyltin dilaurate, butyltin hydroxide hydrate and the like are preferred because of their high activity. The catalyst addition amount and the catalyst addition timing are not particularly limited as long as the reaction can be promoted.

  (II) Post-polycondensation step: Next, at the final reached temperature of the pre-polycondensation step, the pressure in the reactor is gradually reduced so as not to cause bumping while stirring and / or nitrogen bubbling, and the pressure is reduced to 500 to 100 mmHg (66. 5 to 13.3 kPa) and held for several hours to distill the produced alcohol. Thereafter, the temperature is further raised and the pressure is reduced to completely distill the alcohol. The final ultimate pressure is a pressure lower than 3.0 mmHg (399 Pa), further 1.0 mmHg (133 Pa) or higher and lower than 3.0 mmHg (665 Pa), particularly in the range of 1.0 to 2.0 mmHg (266 Pa). Preferably there is. In addition, the reaction temperature is preferably controlled so that the final temperature reaches 160 to 300 ° C, more preferably 180 to 250 ° C.

  Thus, in the present invention, the dialkyl oxalate and the aliphatic diol are reacted in the (I) pre-polycondensation step so that the final temperature reaches 120 to 230 ° C., and then (II) In the post-polycondensation step, the alcohol is distilled while raising the temperature so that the final temperature reaches 160 to 300 ° C. and reducing the final pressure to a pressure lower than 3.0 mmHg (399 Pa). It is preferable to react.

  In the polycondensation reaction, a known reactor can be used. However, in order to advance the reaction efficiently, it is necessary to easily evaporate alcohol generated during the reaction. It is preferable that it can be secured to ensure a wide gas-liquid contact surface. For example, in the case of a vertical reactor, a flask or reaction kettle equipped with a stirrer can be used, and a reactor equipped with a device capable of bubbling an inert gas such as nitrogen into the reaction solution can be used instead of the stirrer. it can. In the horizontal reactor, a kneading apparatus having one or two stirring blades is preferable because the surface area can be efficiently increased. The reactor is preferably for high viscosity. In the polycondensation reaction, a heat-resistant agent may be added if necessary to prevent thermal degradation.

  The high molecular weight polyoxalate resin of the present invention is applied to a general melt processing method such as extrusion molding, injection molding, press molding, hollow molding, vacuum molding, etc., to form a film, sheet, fiber, nonwoven fabric, container, agricultural It can be formed into molded articles such as industrial materials and members. Further, the molded product can be uniaxially or biaxially stretched. Molded articles obtained from these high molecular weight polyoxalate resins of the present invention have high mechanical properties. Therefore, the moldings and molding materials obtained from the high molecular weight polyoxalates of the present invention can be used for various known applications in which thermoplastics are used. Furthermore, the high molecular weight polyoxalate resin of the present invention can be used in various known applications as a plastic having excellent biodegradability.

  The high molecular weight polyoxalate resin of the present invention can be used alone, but if necessary, other components (additives, other polymers, etc.) may be used alone or in combination to form a composition (the poly It can also be used as a material comprising oxalate; powder, chips, beads, etc. Additives that can be blended include, for example, hydrolysis inhibitors, crystal nucleating agents, pigments, dyes, heat resistance agents, anti-coloring agents, antioxidants, weathering agents, lubricants, antistatic agents, stabilizers, fillers (talc, Clay, montmorillonite, mica, zeolite, zonotlite, calcium carbonate, carbon black, silica powder, alumina powder, titanium oxide powder, etc.), reinforcing material (glass fiber, carbon fiber, silica fiber, cellulose fiber, etc.), flame retardant, plasticizer And waterproofing agents (wax, silicone oil, higher alcohol, lanolin, etc.) and the like, and can be added within a range not impairing the effects of the present invention.

  Other polymers that can be blended include natural or synthetic polymers. Examples of the natural polymer include starch, cellulose, chitosan, alginic acid, and natural rubber. Examples of the synthetic polymer include polycaprolactone or a copolymer thereof, polylactic acid or a copolymer thereof, poly Glycolic acid, polysuccinic acid ester, succinic acid / adipic acid copolyester, succinic acid / terephthalic acid copolyester, poly (3-hydroxybutanoic acid), (3-hydroxybutanoic acid / 4-hydroxybutanoic acid) copolymer, polyvinyl alcohol, Polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyvinyl acetate, polyvinyl chloride, polystyrene, polyglutamic acid ester, polyester rubber, polyamide rubber, styrene-butadiene-styrene block copolymer (SBS), hydrogenated SBS, etc. And the like rubber or elastomer.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. However, physical property measurement, structural analysis and molding of the polyoxalate resin were performed as follows.

(1) Water content The water content of the reaction raw material was measured by the Karl Fischer coulometric titration method. The measurement conditions are as follows.
・ Model used: CA-06 manufactured by Mitsubishi Kasei
Operation: The raw material was heated at 200 ° C., and vaporized water was introduced into the Karl Fischer liquid with dry nitrogen and measured.

(2) Solution viscosity ([η])
(I) A reagent grade product in an Ubbelohde viscometer (equipped with a 50 mL reservoir and the water falling time between marked lines at 25 ° C. is 300 seconds) attached to a constant temperature water bath of 25 ± 0.1 ° C. 10 ml of chloroform was charged, and the drop time (t ₀ seconds) between the marked lines was measured after 10 minutes.
(Ii) Next, 0.16 g ± 0.00064 g of the polyoxalate resin was weighed, and 20 mL of chloroform was added to this to completely dissolve the polyoxalate resin at room temperature. 10 mL of the concentration (C ₁ ) = 0.800 g / dL) was charged into an empty viscometer, and the drop time (t ₁ second) between the marked lines was measured after 10 minutes.
(Iii) The reduced viscosity (η _{sp1 / C1} ; dL / g) was obtained from t ₀ , t ₁ and C ₁ by the formula (η _{sp1 / C1} = (t ₁ / t ₀ −1) / C ₁ ).

(Iv) Subsequently, 10 mL of the same chloroform was mixed with the polyoxalate resin-chloroform solution in the viscometer and allowed to stand for 10 minutes, and then this solution (concentration (C ₂ ) = 0.400 g / dL). The time between the marked lines was measured (t ₂ seconds). The reduced viscosity (η _sp2 / C ₂ ; dL / g) was determined from t ₀ , t ₂ and C _{2 in} the same manner as before.
(V) Further, the same operation was performed twice, and the drop times (t ₃ seconds and t ₄ seconds) of solutions having concentrations of 0.267 g / dL (C ₃ ) and 0.200 g / dL (C ₄ ) were respectively determined. It was measured. Reduced viscosities (η _sp3 / C ₃ and η _sp4 / C ₄ ) were determined from t ₀ , t ₃ , C ₃ , and t ₀ , t ₄ , and C _{4 in} the same manner as before.
(Vi) Reduced viscosity (η _sp1 / C ₁ , η _sp2 / C ₂ , η _sp3 / C ₃ , η _sp4 / C ₄ ) and concentration (C ₁ , C ₂ , C ₃ , C ₄ ) obtained by the above measurement ₄ ) The relationship of ( ₄ ) was graphed, and [η] was obtained by extrapolating the concentration to 0 on the graph based on the relationship [η] = (η _sp / C) _{c → 0} .

(3) Number average molecular weight (M _n ): M _n was calculated by the following formula based on the signal intensity obtained from the ¹ H-NMR spectrum. The measurement conditions for ¹ H-NMR are as follows.
・ Model used: JEOL JNM-EX400WB
Solvent: CDCl ₃
・ Number of integration: 32 times ・ Sample concentration: 5% by weight
Calculation formula (when dimethyl oxalate is used as dialkyl oxalate): M _n = n _p × M _p + n _(OH) × [M _(OL) −17] + n _(OCHO) × 45.02 + n _{(OCH 3)} × 103.06

However, each term in the formula is defined as follows.
_{· N p = N p / {} [N (OH) + N (OCHO) + N (OCH3)] / 2}
N _(OH) = N _(OH) / {[N _(OH) + N _(OCHO) + N _(OCH3) ] / 2}
N _(OCHO) = N _(OCHO) / {[N _(OH) + N _(OCHO) + N _(OCH3) ] / 2}
N _(OCH3) = N _(OCH3) / {[N _(OH) + N _(OCHO) + N _(OCH3) ] / 2}
_{· N p = [S p /} s p -1] / s p
N _(OH) = S _(OH) / s _(OH)
N _(OCHO) = S _(OCHO) / s _(OCHO)
N _(OCH3) = S _(OCH3) / s _(OCH3)

Each term has the following meaning.
· N _p: The total number of repeating units other than the repeating units adjacent to the terminal groups of the sample polyoxalate resin.
N _p : average number of repeating units per polyoxalate molecule.
S _p : any hydrogen integral value in the repeating unit excluding the terminal group of the sample polyoxalate resin (for example, 3.95 to 4.42 ppm when 1,4-cyclohexanedimethanol is used as the aliphatic diol) Of signal based on methylene protons).
· _{S p:} The number of hydrogens counted in the hydrogen integrated value _{S p} (e.g., in the case of 1,4-cyclohexanedimethanol 2).
N _(OH) : Total number of terminal hydroxyl groups of the sample polyoxalate resin.
N _(OH) : average number of terminal hydroxyl groups per polyoxalate molecule S _(OH) : arbitrary hydrogen integral value that can identify the terminal hydroxyl group of polyoxalate (for example, 1,4-cyclohexanedimethanol In the case, the integrated value of the signal based on 3.40 to 3.60 ppm methylene protons).
S _(OH) : hydrogen number counted in the hydrogen integral value S _(OH) (for example, 2 in the case of 1,4-cyclohexanedimethanol).
N _(OCHO) : Total number of terminal formate groups of the sample _polyoxalate resin.
N _(OCHO) : average number of terminal formate groups per _polyoxalate molecule.
S _(OCHO) : Any integrated hydrogen value that can identify the terminal formate group of the polyoxalate (for example, in the case of 1,4-cyclohexanedimethanol, the integrated value of the signal based on 8.10 ppm protons).
S _(OCHO) : The number of hydrogens counted in the hydrogen integral value S _(OCHO) (for example, 1 in the case of 1,4-cyclohexanedimethanol).
N _(OCH3) : Total number of terminal methoxy groups of the sample polyoxalate resin.
N _(OCH3) : average number of terminal methoxy groups per polyoxalate molecule.
S _(OCH3) : Arbitrary hydrogen integral value that can identify the terminal methoxy group of polyoxalate (for example, in the case of 1,4-cyclohexanedimethanol, S _(OCH3) is the integral value of the signal based on 3.90 ppm protons. ).
S _(OCH3) : hydrogen number counted in the hydrogen integral value S _(OCH3) (for example, 3 in the case of 1,4-cyclohexanedimethanol).
· M _(OL): molecular weight of the aliphatic diol comprising an aliphatic diol unit of polyoxalate · M _p: Molecular weight of repeating units in the molecular chain.

(4) End group: The end group was identified by ¹ H-NMR spectrum measurement. The measurement conditions are as follows.
・ Model used: JEOL JNM-EX400WB
Solvent: CDCl ₃
・ Number of integration: 32 times ・ Sample concentration: 5% by weight

(5) Measurement of terminal group concentration: When dimethyl oxalate was used, terminal hydroxyl group concentration [OH], terminal formate group concentration [OCHO], and terminal methoxy group concentration [OCH ₃ ] were determined according to the following formulas.
Terminal hydroxyl group concentration [OH] = n _(OH) / M _n
Terminal formate group concentration [OCHO] = n _(OCHO) / M _n
Terminal methoxy group concentration [OCH ₃ ] = n ₍ OCH _{3 )} / M _n

(6) Molding: The polyoxalate resin was hot press molded using a compression molding machine manufactured by Shindo Metal Industries. That is, polyoxalate resin cut into pellets with a plastic cutter was preheated at 210 ° C. for 3 minutes using a 170 μm thick Teflon (registered trademark) film as a release paper, and then pressed at 2.9 MPa for 1 minute. Immediately, a cold press was performed at room temperature for 3 minutes.

[Example 1]
Into a glass reaction tube having a diameter of about 30 mmφ equipped with an air cooling tube and a nitrogen bubbling tube, 12.914 g (0.1094 mol) of dimethyl oxalate (hereinafter abbreviated as DMO), 1,4-cyclohexanedimethanol (trans / cis (weight ratio) = 7/3; hereinafter abbreviated as CHDM) 14.877 g (0.1032 mol) and butyltin hydroxide hydrate 22.7 mg (0.0993 mol% of DMO) Was replaced with nitrogen. Subsequently, a polycondensation reaction (a pre-polycondensation step and a post-polycondensation step) was performed as follows while performing nitrogen bubbling (50 ml / min) during the temperature increase and the reaction. In this case, the charged molar ratio (OL / OX) of dialkyl oxalate (OX) and aliphatic diol (OL) was 0.943, and the water concentration in the raw materials (DMO, CHDM, catalyst) was 170 ppm. .

(I) Pre-polycondensation step: The reaction tube was placed in an oil bath and heated from room temperature to 150 ° C. over 1 hour. Then, it heated up at 190 degreeC and made it react for 1 hour. The contents became a uniform melt when the bath temperature reached about 150 ° C. From about 80 ° C. during the temperature increase, it was observed that crystals of DMO which seem to be due to sublimation adhere to the upper part of the reaction vessel, and methanol distillation was confirmed from about 100 ° C.
(II) Post-polycondensation step: Depressurization was started while maintaining the bath temperature at 190 ° C., the pressure was reduced to 300 mmHg (39.9 kPa) in about 1 hour, and further reduced to 100 mmHg (13.3 kPa) for 1 hour. I let you. Next, while raising the bath temperature to 210 ° C., the pressure reached 1 mmHg (133 Pa) after about 10 minutes while gradually decreasing the pressure, and the reaction was performed at 210 ° C. and 1 mmHg (133 Pa) for 4 hours.

19.7 g of the obtained polycyclohexylene dimethylene oxalate resin (hereinafter abbreviated as PCHDMOX) has [η] = 0.99 dL / g, M _n = 28400, [OH] = 0.06 × 10 ⁻⁵ eq / G, [OCHO] = 1.10 × 10 ⁻⁵ eq / g, [OCH ₃ ] = 0.87 × 10 ⁻⁵ eq / g, ([OCH ₃ ] + [OCHO]) / ([OH] + [OCH ₃ ] + [OCHO]) = 0.280, and a tough sheet could be formed by hot press molding.

[Example 2]
DMO 13.642 g (0.1155 mol), CHDM 15.717 g (0.1090 mol) and butyltin hydroxide hydrate 2.4 mg (0.01 mol% of DMO) were charged, and 1 mmHg (133 Pa) in the post-polymerization step The polycondensation reaction was carried out in the same manner as in Example 1 except that the polymerization time in was 9 hours. Note that OL / OX = 0.944, and the water concentration in the raw material was 170 ppm.
The obtained PCHDMOX 20.3 g had [η] = 1.47 dL / g, M _n = 45500, [OH] = 3.50 × 10 ⁻⁵ eq / g, [OCHO] = 0.72 × 10 ⁻⁵ eq / G, [OCH ₃ ] = 0.17 × 10 ⁻⁵ eq / g, ([OCH ₃ ] + [OCHO]) / ([OH] + [OCH ₃ ] + [OCHO]) = 0.203. A tough sheet could be formed by hot press molding.

Example 3
In a 0.5 L (liter) glass reaction vessel equipped with a stirrer, thermometer and nitrogen gas inlet / outlet, DMO 28.93 g (0.2450 mol), CHDM 32.11 g (0.2227 mol) and butyltin Hydroxide hydrate 5 mg (0.01 mol% of DMO) was charged, and the inside was replaced with nitrogen. Subsequently, a polycondensation reaction (a pre-polycondensation step and a post-polycondensation step) was performed as follows. Note that OL / OX = 0.909, and the water concentration in the raw material was 170 ppm.

(I) Pre-polycondensation step: The temperature in the container was raised from room temperature to 150 ° C. over 1 hour. After the contents were melted, the reaction was carried out by starting stirring at 25 rpm. Nitrogen was introduced at a flow rate of 50 ml / min during the temperature rise and reaction. From about 60 ° C. during the temperature increase, it was observed that crystals of DMO which seem to be due to sublimation adhere to the upper part of the reaction vessel, and methanol was confirmed to be distilled from about 100 ° C. Immediately after the temperature reached 150 ° C., the temperature was started to rise to 190 ° C. over about 1 hour.
(II) Post-polycondensation step: Depressurization was started while maintaining the temperature in the vessel at 190 ° C., and the pressure was reduced to 300 mmHg (39.9 kPa) in about 1 hour while distilling methanol. Next, the pressure was reduced to 100 mmHg (13.3 kPa) in about 1 hour. Next, while raising the temperature to 210 ° C., the pressure was gradually lowered to reach 1 mmHg (133 Pa) after about 15 minutes, and the reaction was performed at 210 ° C. and 1 mmHg (133 Pa) for 6 hours.
The obtained PCHDMOX 44.2 g had [η] = 0.78 dL / g, M _n = 24500, [OH] = 2.00 × 10 ⁻⁵ eq / g, [OCHO] = 0.28 × 10 ⁻⁵ eq / G, [OCH ₃ ] = 5.88 × 10 ⁻⁵ eq / g, ([OCH ₃ ] + [OCHO]) / ([OH] + [OCH ₃ ] + [OCHO]) = 0.755. A tough sheet could be formed by hot press molding.

Example 4
Polycondensation as in Example 3 except that 25 mg of butyltin hydroxide hydrate (0.05 mol% of DMO) was charged and the polymerization time at 1 mmHg (133 Pa) in the post-polymerization step was 4.5 hours. Reaction was performed. OL / OX and the water concentration in the raw material were the same as in Example 3.
The obtained PCHDMOX 44.0 g had [η] = 0.99 dL / g, M _n = 28800, [OH] = 2.92 × 10 ⁻⁵ eq / g, [OCHO] = 0.66 × 10 ⁻⁵ eq / G, [OCH ₃ ] = 3.38 × 10 ⁻⁵ eq / g, ([OCH ₃ ] + [OCHO]) / ([OH] + [OCH ₃ ] + [OCHO]) = 0.580 A tough sheet could be formed by hot press molding.

[Comparative Example 1]
Example 1 except that 11.81 g (0.100 mol) of DMO, 14.42 g (0.100 mol) of CHDM and 2.1 mg of butyltin hydroxide hydrate (0.01 mol% of DMO) were charged. The polycondensation reaction was performed. Note that OL / OX = 1.000, and the water concentration in the raw material was 170 ppm.
The obtained PCHDMOX 17 g had [η] = 0.38 dL / g, M _n = 8600, [OH] = 22.1 × 10 ⁻⁵ eq / g, [OCHO] = 0.37 × 10 ⁻⁵ eq / g. , [OCH ₃ ] = 0.90 × 10 ⁻⁵ eq / g, ([OCH ₃ ] + [OCHO]) / ([OH] + [OCH ₃ ] + [OCHO]) = 0.054. When this polymer was hot press molded, the obtained sheet was a brittle sheet.

[Comparative Example 2]
A polycondensation reaction was carried out in the same manner as in Example 1 except that 11.81 g (0.100 mol) of DMO and 6.92 g (0.048 mol) of CHDM were charged. Note that OL / OX = 0.480, and the water concentration in the raw material was 121 ppm.
The obtained PCHDMOX was 8.5 g, and only a brittle sheet was obtained when this polymer was hot-press molded.

[Comparative Example 3]
The polycondensation reaction was carried out in the same manner as in Example 1 except that 11.825 g (0.1002 mol) of DMO and 13.611 g (0.0907 mol) of CHDM were added and 0.01 mol% of butyltin hydroxide hydrate was added. Went. Note that OL / OX = 0.905, and the water concentration in the raw material was 2100 ppm.
The obtained PCHDMOX21 g had [η] = 0.29 dL / g, M _n = 4800, [OH] = 15.2 × 10 ⁻⁵ eq / g, [OCHO] = 24.8 × 10 ⁻⁵ eq / g. , [OCH ₃ ] = 1.85 × 10 ⁻⁵ eq / g, ([OCH ₃ ] + [OCHO]) / ([OH] + [OCH ₃ ] + [OCHO]) = 0.637. This polymer was hot press molded, but only a brittle sheet was obtained.

Example 5
In a pressure vessel having an internal volume of 5 L equipped with a stirrer, a thermometer, a pressure gauge, a nitrogen gas inlet, a pressure outlet, and a polymer outlet, DMO 2025.0 g (17.148 mol), CHDM 2312.0 g (16.032 mol) ), 3.6 g of butyltin hydroxide hydrate (0.100 mol% of DMO) and 21.6 g of heat-resistant irgaphos 168 (manufactured by Ciba Specialty Chemicals) (5000 ppm of the raw material), and the inside with nitrogen Replaced. Next, a polycondensation reaction was performed as follows. Note that OL / OX = 0.935, the water concentration in DMO was 478 ppm, and the water concentration in CHDM was 200 ppm.

(I) Pre-polycondensation step: The temperature in the pressure vessel was raised from room temperature to 100 ° C. over 1.25 hours. After confirming that the melt was uniform, the reaction was carried out while raising the temperature to 150 ° C. over 2 hours. The amount of distilled methanol in the process of raising the temperature was 394.5 g. Subsequently, it was made to react further, heating up to 190 degreeC over 2 hours. The total methanol distillate amount was 434.5 g.

(II) Post-polycondensation step: Depressurization was started while maintaining the temperature in the pressure vessel at 190 ° C., the pressure was reduced to 300 mmHg (39.9 kPa) in 0.75 hours, and 100 mmHg (13.3 kPa) in 1 hour. The reaction was performed under reduced pressure. During this time, the total amount of methanol distilled was 484.5 g. Next, the temperature in the pressure vessel is increased to 207 ° C. over 1.5 hours, and gradually decreased to 5 mmHg (665 Pa) after 1.25 hours while gradually reducing the pressure, and further to 0.8 mmHg (106 Pa) after 4 hours. The reaction was carried out. Thereafter, the stirring was stopped, and the melted contents were drawn out from the polymer outlet through a string, cooled with water, and pelletized.

The obtained PCHDMOX (2430 g) has a melting point (by differential scanning calorimetry) of 174 ° C., [η] = 0.89 dL / g, M _n = 35100, [OH] = 3.19 × 10 ⁻⁵ eq / G, [OCHO] = 0.67 × 10 ⁻⁵ eq / g, [OCH ₃ ] = 1.84 × 10 ⁻⁵ eq / g, ([OCH ₃ ] + [OCHO]) / ([OH] + _{[OCH 3] + [OCHO]} ) it was a = 0.440.

  Next, using a twin screw extruder, at 190 ° C., 1 wt% of hydrolysis inhibitor Carbodilite LA-1 (Nisshinbo), 0.1 wt% of HMV-8CA (Nisshinbo), The heat-resistant agent Irgafos 168 was blended at 0.32% by weight, and Irganox 1010 (manufactured by Ciba Specialty Chemicals) was blended at 0.25% by weight. All blending ratios are ratios to pellets.

  Using the obtained pellets, a hot-pressed sheet (thickness: 141 μm) was produced by sheet molding, and tensile properties were measured. Sheet molding was performed by using a compression molding machine manufactured by Shinto Metal Industry, preheating at 190 ° C. for 3 minutes, pressing at 2.9 MPa for 3 minutes, and then rapidly cooling to 20 ° C. Tensile properties were measured by performing a tensile test under the following conditions using a JIS No. 2 tensile test piece punched from a hot press sheet. As a result, the tensile strength was 23.5 MPa, the tensile modulus was 1.44 GPa, and the elongation at break was 200%.

-Model used: Orientec Tensilon-Sample used: JIS No. 2 tensile test piece (straight part length 50 mm, width 5 mm)
・ Tensile speed: 10 mm / min ・ Measurement temperature: 23 ° C.
・ Measurement humidity: 50% RH

Next, a biodegradability test was performed using the hot press sheet. That is, after cutting out a small piece of about 1 cm × 1 cm from a hot press sheet and embedding it in compost, the embedded object is left standing in a constant temperature bath at 30 ° C. for a predetermined time, and the embedded object is washed and dried. Biodegradability was evaluated based on the appearance and weight residual ratio (%) by weight measurement. As a result, the weight residual ratio after 62 days was 78%.
The calculation was based on the following formula. However, W represents the small piece weight (mg) after the embedding process, and W ₀ represents the small piece weight (mg) before the embedding process.
Weight residual ratio (%) = W / W ₀ × 100

Since the high molecular weight polyoxalate resin of the present invention can be molded by a general melt processing method applied to ordinary thermoplastics, it can be used as a sheet, film, tube, fiber, injection-molded product, foam, etc. Molded articles with sufficient mechanical properties that can be used in a wide range of fields can be produced.

Claims (4)

The ratio of dialkyl oxalate and aliphatic diol is within the range of 0.5 ≦ OL / OX <1, and the water concentration in the raw material is controlled to less than 2000 ppm, so that the polyalkyl oxalate and aliphatic diol are polycondensed. To produce polyoxalate,
(However, OX represents the number of moles of dialkyl oxalate, and OL represents the number of moles of aliphatic diol.)
It has either an alkoxy group, a hydroxyl group, or a formate group represented by the following chemical formula at the end.
The manufacturing method of high molecular weight polyoxalate resin which consists of polyoxalate which becomes .

(In the formula, A represents an alkylene group having 3 to 12 carbon atoms in the main chain, which may contain a branched structure or an alicyclic structure, and n is a positive integer representing the degree of polymerization. , X represents H-, ROCOCO-, or OHC-, and when X is H-, Y represents -OR, -OAOH, or -OAOCHO, and X represents ROCOCO- or OHC-. , Y represents —OR or —OAOCHO, and R represents an alkyl group.) The manufacturing method of the high molecular weight polyoxalate resin of Claim 2 which controls the water concentration in a raw material to 10-2000 ppm. A high molecular weight polyoxalate resin composed of a polyoxalate represented by the following chemical formula, having an alkoxy group, a hydroxyl group, or a formate group at the end ,

i) When the terminal group bonded to the molecular terminal on the ether group (-O-) side of the repeating unit is H-:
The terminal group bonded to the molecular terminal on the other carbonyl group (—CO—) side is one of —OR, —OAOH, and —OAOCHO,
ii) When the terminal group bonded to the molecular terminal on the ether group (-O-) side of the repeating unit is ROCOCO- or OHC-: The terminal group bonded to the molecular terminal on the other carbonyl group (-CO-) side is -OR or -OAOCHO,
i) consists only of ii),
The ratio of the dialkyl oxalate and the aliphatic diol is within the range of 0.5 ≦ OL / OX <1, and the water concentration in the raw material is controlled to less than 2000 ppm to obtain a polycondensation reaction,
0.1 ≦ ([OR] + [OCHO]) / ([OH] + [OR] + [OCHO]) ≦ 1.0 is satisfied,
The number average molecular weight is 20,000 to 100,000,
A high molecular weight polyoxalate resin characterized by excellent color tone .
(However,
OX represents the number of moles of dialkyl oxalate, and OL represents the number of moles of aliphatic diol.
[OR] represents the concentration of the terminal alkoxy group of the polyoxalate, [OCHO] represents the concentration of the terminal formate group of the polyoxalate, and [OH] represents the concentration of the terminal hydroxyl group of the polyoxalate. ) The high molecular weight polyoxalate resin according to claim 3 , wherein R is a methyl group.