JP2006161017A - Novel polyoxalate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide isosorbide biodegradable polyester for dramatically improving heat resistance which is the problem of prior art. <P>SOLUTION: The novel polyoxalate is an isosorbide-based polyester which is obtained by combining an oxalic acid diester with isosorbide, and comprises a structural unit of formula (I) as its main repeating unit. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an isosorbide-based polyester (new polyoxalate) having biodegradability and excellent heat resistance.

JP-A-11-241004 Polym. Bull. , 11, 365 (1984) Makromol. Chem. , 194, 53 (1993) J. et al. Polymer Sci. : Part A: Polymer Chemistry, 33, 2813 (1995) J. et al. Appl. Polymer Sci. , 62, 2257 (1996) J. et al. Appl. Polymer Sci. , 77, 338 (2000)

  In recent years, material development using raw materials derived from renewable plant resources typified by polylactic acid has been actively developed as a solution to the plastic disposal problem given to the global environment. As one of them, from raw materials obtained by decomposition and modification from polysaccharides such as starch and cellulose, among them, isosorbide obtained by reduction and intramolecular dehydration cyclization of glucose produced by hydrolysis of starch and dicarboxylic acid derivatives The resulting polyester is well known.

  Examples of polyesters using isosorbide include polyesters obtained from isosorbide and terephthalic acid chloride (Non-Patent Documents 1 and 2), and polyesters obtained from isosorbide and aromatic or alicyclic dicarboxylic acids (Patent Document 1). However, in particular, the latter is intended for liquid crystal applications, and there is no description about heat resistance, biodegradability and the like.

  In addition, as polyester obtained from isosorbide and aliphatic dicarboxylic acid derivative, using acid chloride compounds of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid. Polyesters to be synthesized are known (Non-Patent Documents 3, 4, and 5). However, all of these polyesters are biodegradable, but do not exhibit a melting point, are amorphous, and have a very low glass transition temperature of about 36 ° C. at the highest when using the highest glass transition temperature. It was lacking in practicality.

  An object of the present invention is to provide an isosorbide-based biodegradable polyester having greatly improved heat resistance, which is a problem of the prior art.

  The present inventors have found that an isosorbide-based polyester (new polyoxalate) represented by the following formula is obtained by combining an oxalic acid diester with isosorbide, and the above problem can be solved by this polyester. In particular, the very high glass transition temperature of the isosorbide-based polyester of the present invention could not be predicted at all from the glass transition temperature of conventionally known isosorbide-based polyester.

  That is, the present invention provides (1) a novel polyoxalate containing a structural unit represented by formula (I) as a main repeating unit, and (2) a structural unit represented by formula (I). (3) The novel polyoxalate according to the first invention comprising an ester unit and / or a lactic acid unit different from the structural unit represented by the formula (I) as an additional repeating unit. is there.

In addition, the present invention provides (4) a polyoxalate comprising the polyoxalate according to any one of the above 1 to 3, and having an oxygen permeability of 1.0 ml · mm / m ² · day · atm or less. Also on rate film.

  As will be apparent from the examples described later, the novel polyoxalate of the present invention is a polymer excellent in heat resistance and chemical resistance, and therefore, as a molded article or fiber, the transparency is very good. Therefore, it is useful as a film, a sheet, a container and the like, and can be used as various members, parts, and materials in a wide range of fields such as automobiles, electricity / electronics, precision equipment, food, agriculture, household and household goods.

  In addition, the polyoxalate film of the present invention has excellent oxygen barrier properties in addition to heat resistance, chemical resistance and transparency, so that it is a packaging material or packaging container for foods, pharmaceuticals, cosmetics, precision equipment, home appliances, etc. As particularly useful. In addition, since the polyoxalate and polyoxalate film of the present invention are biodegradable and use renewable plant resource-derived raw materials, the burden on the global environment due to disposal is very small. It is.

  The polyoxalate of the present invention contains the structural unit represented by the formula (I) as a main repeating unit, and the polyoxalate comprises the structural unit represented by the formula (I). In addition to the main repeating unit of the formula (I), an additional ester unit and / or a lactic acid unit different from that may be included as an additional repeating unit.

  In the former case, the polyoxalate of the present invention can be represented by the formula (II), where “n” is a positive integer representing the degree of polymerization and is related to the molecular weight. In the latter case, the ratio of the additional repeating unit depends on the above-described effects of the present invention (particularly high heat resistance; glass transition temperature is 160 ° C. or higher) and the original characteristics (biodegradation) of the polyoxalate of the present invention. For example, 50 mol% or less, preferably 30 mol% or less, based on all repeating units (total of main repeating units and additional repeating units). In addition, although the polyoxalate of this invention does not have a special restriction | limiting in molecular weight or molecular weight distribution, The thing whose number average molecular weight is the range of 10,000-100000 is more preferable.

  The polyoxalate of the present invention can be produced by a polycondensation reaction between isosorbide as a main raw material and oxalic acid or a derivative thereof (oxalic acid diester, oxalic acid dichloride, etc.). It is particularly preferable to produce by a condensation reaction. The proportion of isosorbide used relative to 1 mol of oxalic acid or its derivative is preferably 0.95 to 1.05 mol, more preferably 0.98 to 1.02 mol, especially equimolar, and these are added as described later. Even when the acid component or the alcohol component is substituted, the ratio of the additional acid component to the alcohol component can be appropriately selected, but the ratio of the total alcohol to the total acid component is preferably the same as described above.

  As the oxalic acid diester, dialkyl oxalate (dimethyl oxalate, diethyl oxalate, dibutyl oxalate, etc.), diaryl oxalate (diphenyl oxalate, di-p-tolyl oxalate, etc.), or a combination thereof can be used.

  Isosorbide is a diol of a bicyclic ether (tetrahydrofuran ring) represented by the formula (III), also called 1,4: 3,6-dianhydro-D-glucitol or 1,4: 3,6-dianhydro-D-sorbitol. Yes, constituting the diol part of the structural unit.

  In addition, from the three-dimensional structure of isosorbide, the structural unit represented by the formula (I) usually comprises two structural units represented by the following formula. The structural unit in the formula (II) also includes these two types of structural units.

  When the polyoxalate of the present invention contains an additional ester unit different from the formula (I) as an additional repeating unit, in the polycondensation reaction, part of oxalic acid or a derivative thereof (oxalic acid component) is an additional acid component Is replaced by As an additional acid component, other dicarboxylic acids different from oxalic acid (terephthalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, etc.), Other dicarboxylic acid derivatives different from oxalic acid derivatives (for example, dicarboxylic acid diesters such as dimethyl terephthalate, dimethyl succinate, and dimethyl adipate), carbonic acid diesters (dimethyl carbonate, diphenyl carbonate, etc.), or combinations thereof . This substitution ratio is not particularly limited as long as it does not impair the effects of the present invention and the original characteristics of the polyoxalate of the present invention. For example, the additional acid component is a total acid component (oxalic acid). 50 mol% or less, preferably 30 mol% or less with respect to the total of the component and the additional acid component).

  Similarly, when an additional ester unit is included, a part of isosorbide (main alcohol component) is substituted with the additional alcohol component in the polycondensation reaction. This substitution ratio is not particularly limited as long as it does not impair the effects of the present invention and the original characteristics of the polyoxalate of the present invention. For example, the additional alcohol component is a total alcohol component (main alcohol). 50 mol% or less, preferably 30 mol% or less, based on the sum of the components and the additional alcohol component).

  Additional alcohol components include stereoisomers of isosorbide represented by the above formula (1,4: 3,6-dianhydro-D-mannitol, 1,4: 3,6-dianhydro-L-iditol), aliphatic diols (Ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9- Nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, neopentyl glycol, etc.), alicyclic diol (trans (or cis) -1,4-cyclohexanedimethanol, etc.) Aromatic diols (p-xylylene glycol, m-xylylene glycol, o-xylylene glycol, Dorokinon, bisphenol A, etc.), different heterocyclic and isosorbide and isosorbide isomers polyhydric alcohol (D-sorbitol), or combinations thereof.

  When the polyoxalate of the present invention contains a lactic acid unit as an additional repeating unit, the main raw materials isosorbide and oxalic acid or a derivative thereof so that the lactic acid unit falls within the above range with respect to all the repeating units in the polycondensation reaction. In addition, lactic acid components such as lactic acid, polylactic acid, and lactide are added. In addition, the polyoxalate of this invention may contain both the additional ester unit and the lactic acid unit in the said range as an additional repeating unit.

  The polyoxalate of the present invention can be obtained by subjecting isosorbide and oxalic acid or a derivative thereof (preferably oxalic acid diester) to a polycondensation reaction (preferably melt polymerization) in a batch or continuous manner. At this time, components of additional repeating units are added as necessary. 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) Pre-polycondensation step: An oxalic acid diester and isosorbide are charged into a reactor, and after the inside of the reactor is purged with nitrogen, the temperature is gradually raised while stirring and / or nitrogen bubbling so as not to cause bumping. 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, the reaction solution contains the produced alcohol (such as methanol).

In the polycondensation reaction, it is preferable to use a catalyst as necessary. Preferred examples of such a catalyst include compounds such as P, Ti, Ge, Zn, Fe, Sn, Mn, Co, Zr, V, Ir, La, Ce, Li, Ca, and Hf. Of these, organic titanium compounds and organic tin compounds are preferable. For example, titanium alkoxide (titanium tetrabutoxide, titanium tetraisopropoxide, etc.), distanoxane compound (1-hydroxy-3-isothiocyanate-1,1,3,3) -Tetrabutyl 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 polyoxalate can be obtained quickly, but it is preferably 10 ⁻⁵ to 10 ⁻³ mol with respect to 1 mol of oxalic acid diester.

  (Ii) Post-polycondensation step: Next, at the final temperature of the pre-polycondensation step, the pressure inside the reactor is gradually reduced so as not to bump 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 (400 Pa), more than 1.0 mmHg (133 Pa) and lower than 3.0 mmHg (400 Pa), particularly in the range of 1.0 to 2.0 mmHg (133 to 266 Pa). A pressure is preferred. 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 oxalic acid diester and isosorbide are reacted in the (I) pre-polycondensation step by raising the final reached temperature to 120 to 230 ° C., and then (II) In the condensation step, the temperature is raised so that the final reached temperature is in the range of 160 to 300 ° C., and the alcohol is distilled and reacted while reducing the pressure so that the final reached pressure is lower than 3.0 mmHg (400 Pa). It is preferable to manufacture.

  The polyoxalate of the present invention can be used alone, but if necessary, other components (additives, other polymers, etc.) may be added alone or in combination to give a composition (the polyoxalate It can also be used as a material comprising; powder, chips, beads, etc. This blending amount is in a range that does not impair the effects of the present invention, but is preferably blended in the range of 0.01 to 10% by weight of the polyoxalate. Additives that can be blended include, for example, 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 materials (glass fiber, carbon fiber, silica fiber, etc.), flame retardant, plasticizer, waterproofing agent (wax, silicone oil) , Higher alcohols, lanolin, etc.), hydrolysis stabilizers (polycarbodiimide resins, etc.) and the like.

  Other polymers that can be blended include natural or synthetic polymers. Examples of the natural polymer include starch, cellulose acetate, chitosan, alginic acid, and natural rubber. Examples of the synthetic polymer include polycaprolactone or a copolymer thereof, polylactic acid or a copolymer thereof, Polyglycolic 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 , And the like rubber or elastomer BS like.

  The polyoxalate of the present invention is formed into molded products, films, sheets, fibers, nonwoven fabrics, containers, etc. by applying general melt molding methods such as extrusion molding, injection molding, press molding, hollow molding, vacuum molding, etc. can do. Further, the molded product can be uniaxially or biaxially stretched. Moreover, a molded article can also be manufactured using the solution melt | dissolved in the solvent. Molded articles obtained from these polyoxalates of the present invention have high heat resistance, and can be used for various known applications in which thermoplastic plastics are used. Furthermore, the polyoxalate of the present invention can be used for various known applications as a plastic having excellent biodegradability.

The polyoxalate film of the present invention is obtained by molding the polyoxalate into a film shape, and has an oxygen permeability of 1.0 ml · mm / m ² · day · atm (4.13 × 10 ⁻⁷ ml · mm / m ² · hr · Pa) or less, preferably 0.8 ml · mm / m ² · day · atm (3.30 × 10 ⁻⁷ ml · mm / m ² · hr · Pa) or less. The oxygen permeability is a value measured by “ASTM D3985” converted to a thickness of 1 mm for a film having a thickness of 180 μm.

  The thickness of the polyoxalate film of the present invention is not particularly limited as long as the oxygen permeability is in the above range and the desired mechanical strength and flexibility can be obtained, but is usually about 5 to 300 μm, Is preferably about 10 to 200 μm. If the film is too thin, the desired mechanical strength cannot be obtained, and defects such as tearing and pinholes tend to occur. Conversely, if the film is too thick, satisfactory flexibility cannot be obtained.

  The polyoxalate film obtained by the above-mentioned general molding method is a uniaxial stretching, a sequential biaxial stretching, or a simultaneous biaxial with a constant width at an appropriate temperature (preferably 160 to 200 ° C.) higher than the glass transition temperature. Stretching can be performed, and mechanical properties can be improved by stretching. The length draw ratio is preferably in the range of 1.5 to 6.0, more preferably 2.5 to 6.0. If the length draw ratio is 1.5 or less, the effect of stretching may not be substantially observed, and if it is 6 or more, the uniformity of the film may be lost. In the biaxial stretching, the area stretching ratio is preferably in the range of 2.25 to 36. Furthermore, you may stabilize a dimension by giving heat processing (heat set) after extending | stretching. This heat treatment is performed at 170 to 210 ° C. for 1 to 300 seconds, for example.

  Since the polyoxalate film of the present invention is excellent in transparency, gas barrier properties, and biodegradability, it can be used as a wrapping film and packaging materials (packaging containers) for various articles. The form of packaging is not particularly limited, but household wrap, pouch (including standing), skin pack, shrink packaging, pillow packaging, rocket packaging, blister pack, deep drawing packaging, tray cup packaging, portion pack, strip packaging, etc. Can be used for

  The package is not particularly limited, such as food, pharmaceuticals, cosmetics, precision machinery, and home appliances. Specific examples include cereals and processed cereals such as flour, rice, rice cake, noodles, and instant noodles; meat and processed meat products such as meat, processed meat products, prepared meats and chicken eggs; and milk such as milk, butter, and cheese Dairy products; Fresh food, processed fishery products, meat-mixed products, fresh fish and fishery products such as shavings; vegetables and fruits such as vegetables, fruits, fruit drinks and cut vegetables; confectionery and bread such as confectionery, bread, candy, and chocolate ; Fermented foods such as fermented marine products, miso, soy sauce, pickles, sake, wine; seasonings such as mayonnaise, dressing, tomato ketchup, sauce, vinegar, edible oil; Japanese tea, coffee, oolong tea, black tea, soft drinks, spices Specialty products such as retort foods, frozen foods, boiled boiled fish, and delicacies; daily cooked foods such as bento side dishes, cooked bread, sandwiches, konjac, tofu, and cooked rice Medical products such as solid preparations, liquids, ointments; cosmetics, powder detergents, toothpastes, shampoos, solid soaps, disposable diapers, sanitary products, etc .; PCs, printers, cameras, TVs, refrigerators, portable audio devices, batteries, Examples thereof include precision machines such as IC chips, optical and / or magnetic recording media, and home appliances.

  The polyoxalate film of the present invention is, for example, agricultural / horticultural supplies such as multi-films for agriculture / horticulture, seed tape, germination sheets, curing sheets, seedling pots, bird nets, pesticide bags, compost garbage bags, etc. It can also be used preferably for household goods such as garbage bags, draining bags, supermarket shopping bags, and office supplies such as window frame envelopes and cover films for printing paper.

  Next, the present invention will be specifically described with reference to examples. The polyoxalate was evaluated as in the following 1-4, and the film formation and the evaluation were performed as in the following 5-7.

1. Reduced viscosity (η _SP / c)
Measurement was performed at 25 ° C. using a hexafluoroisopropanol solution of polyoxalate (concentration: 0.5 g / dl).

2. Glass transition temperature (T _g ) and melting point (T _m )
It was determined by DSC measurement (temperature increase and temperature decrease rate: 10 ° C./min, under nitrogen atmosphere).

3. Biodegradation characteristics Compost is placed in a test container (made of glass, 1 L capacity), and after granulated polyoxalate is embedded in the container, the container is held at 58 ° C. and air (from the bottom to the top) After de-CO ₂ , water that was passed through water at 58 ° C. and was humidified was circulated, and exhaust gas from the container was introduced into the NaOH aqueous solution to absorb CO ₂ in the exhaust gas. Decomposition rate, by subtracting the amount of CO ₂ produced blank test from CO ₂ generation amount after a predetermined time, obtains the amount of produced CO ₂ from the sample, the ratio (percentage of the theoretical CO ₂ emission from a sample of this value ). The CO ₂ generation amount was calculated by measuring the inorganic carbon concentration (by titration) in the NaOH aqueous solution.

4). Transparency and chemical resistance After preparing a hexafluoroisopropanol solution of polyoxalate (concentration: 10% by weight) and casting it on a glass plate at room temperature, it was dried at room temperature to remove the solvent, and the thickness was about 100 μm. A film was prepared. Transparency was judged by visual observation of the film, and further, a 1 cm square test piece was cut out from the film and immersed in various chemicals at room temperature for 24 hours, and then chemical resistance was judged by visual observation of the appearance of the test piece.

5. Film forming Using a Katotech vacuum sheet making device, using polyimide film as a release sheet, about 2.5 g of polyoxalate is placed on a hot plate and kept at 240 ° C. for 3 minutes while reducing pressure with a vacuum pump. And compressed at 100 kgf / cm ² (10 MPa) for 1 minute. Thereafter, the entire release sheet was taken out and air-cooled at room temperature to obtain a film having a thickness of 180 to 300 μm and a diameter of 80 to 100 mm.

6). Oxygen permeability About the test piece cut out from the above film, using a test machine OX-TRAN2 / 20-MH manufactured by MOCON, under conditions of temperature 23 ° C., humidity 0% RH and 65% RH, based on “ASTM D3985” It was measured.

7). Tensile properties Using a tensile tester Tensilon manufactured by Orientec, the tensile properties of the dumbbell type JIS No. 3 tensile test piece punched from the film were measured at a temperature of 23 ° C. and a humidity of 50% RH at a tensile speed of 10 mm / min. .

[Example 1]
In a glass reaction tube (equipped with an air-cooled tube and a nitrogen bubbling tube) having a diameter of about 30 mmφ, 24.223 g (0.1 mol) of diphenyl oxalate, 14.616 g (0.1 mol) of isosorbide and butyltin hydroxyoxide hydrate ( C ₄ H ₉ Sn (O) OH.xH ₂ O) 2.1 mg (0.01 mol% with respect to diphenyl oxalate) 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. In addition, nitrogen bubbling (50 ml / min) was performed during temperature rising and reaction.

(I) Pre-polycondensation step: The reaction tube was placed in an oil bath and reacted while raising the temperature from room temperature to 190 ° C. over 1.5 hours. The contents became a homogeneous melt when the bath temperature was about 140 ° 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. During this time phenol began to distill. Next, the bath temperature was raised to 200 ° C., and the reaction was carried out for 2 hours while gradually increasing the degree of vacuum. The final ultimate pressure was 0.5 mmHg (66.5 Pa). The physical property measurement results of the obtained polyoxalate (PISOX-1) are shown together in Table 1. The ¹ H-NMR spectrum is shown in FIG. The number average molecular weight of the polyoxalate is determined by ¹ H-NMR, and “n” in FIG. 1 represents the degree of polymerization. ¹ H-NMR was measured using JNM-EX400WB manufactured by JEOL under the conditions of solvent: DMSO-d ₆ , integration number: 32 times, sample concentration: 5 wt%.

[Example 2]
Using a glass reaction tube having a diameter of about 30 mmφ equipped with a stir bar, the amount of isosorbide used was changed to 14.373 g (0.09834 mol), and in the post-polycondensation step, the phenol began to distill, and then the bath temperature was increased. A polyoxalate (PISOX-2) was obtained by carrying out the reaction in the same manner as in Example 1 except that the reaction was carried out for 7 hours while gradually raising the degree of vacuum while raising the temperature to 215 ° C. The physical property measurement results are shown in Table 1.

Example 3
A polyoxalate (PISOX-3) was obtained by carrying out the reaction in the same manner as in Example 2 except that the amount of isosorbide used was changed to 14.382 g (0.0984 mol). The physical property measurement results are shown in Table 1.

Since the isosorbide-based polyester (new polyoxalate) of the present invention has biodegradability, it has little impact on the global environment due to disposal, and is used in automobiles, electricity / electronics, precision equipment, food, agriculture, household and household goods. Can be used as various members, parts, and materials (for example, as molded products, films, sheets, containers, fibers, etc.).
In addition, the polyoxalate film of the present invention has excellent oxygen barrier properties in addition to heat resistance, chemical resistance and transparency, so that it is a packaging material or packaging container for foods, pharmaceuticals, cosmetics, precision equipment, home appliances, etc. As particularly useful.

The ¹ H-NMR spectrum of the polyoxalate (PISOX-1) obtained in Example 1 is shown.

Claims (4)

A novel polyoxalate containing a structural unit represented by formula (I) as a main repeating unit.

The novel polyoxalate of Claim 1 which consists of a structural unit represented by said Formula (I). The novel polyoxalate of Claim 1 which contains the ester unit and / or lactic acid unit different from the structural unit represented by said Formula (I) as an additional repeating unit. A polyoxalate film comprising the polyoxalate according to any one of claims 1 to 3 and having an oxygen permeability of 1.0 ml · mm / m ² · day · atm or less.

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