阅读说明：本技术 生物基聚碳酸酯及其制备方法 (Bio-based polycarbonate and preparation method thereof ) 是由 吴光世 李锺寅 于 2019-01-24 设计创作，主要内容包括：本发明涉及生物基聚碳酸酯及其制备方法,并且更具体地,涉及通过使用高粘度缩聚反应器来制备具有优异的机械特性例如抗拉强度和冲击强度的生物基聚碳酸酯的方法。(The present invention relates to a bio-based polycarbonate and a method for preparing the same, and more particularly, to a method for preparing a bio-based polycarbonate having excellent mechanical properties such as tensile strength and impact strength by using a high viscosity polycondensation reactor.)

1. A method for preparing a bio-based polycarbonate, the method comprising: feeding a monomer mixture comprising 1,4:3, 6-dianhydrohexitol and at least one compound selected from the group consisting of compounds represented by the following formulas 1 to 3 to a high viscosity polycondensation reactor; and reacting them:

[ formula 1]

[ formula 2]

[ formula 3]

In the above-mentioned formula 2, the first,

R¹and R²Each being an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 18 carbon atoms,

wherein the aryl group may have at least one substituent selected from the group consisting of: an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 4 to 20 carbon atoms, an aryl group having 6 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, a cycloalkoxy group having 4 to 20 carbon atoms, an aryloxy group having 6 to 18 carbon atoms, an alkylsulfonyl group having 1 to 18 carbon atoms, a cycloalkylsulfonyl group having 4 to 20 carbon atoms, an arylsulfonyl group having 6 to 18 carbon atoms, and an ester substituent; and the ester substituent may be an alkyl ester having 1 to 18 carbon atoms, a cycloalkyl ester having 4 to 20 carbon atoms, or an aryl ester having 6 to 18 carbon atoms.

2. The method for preparing a bio-based polycarbonate according to claim 1, wherein the high viscosity polycondensation reactor is a post-polycondensation reactor including one or more stirrers, a kneader, or an extruder.

3. The method for preparing a bio-based polycarbonate according to claim 1, wherein a maximum attained viscosity in the high-viscosity polycondensation reactor is 10000 poise to 1000000 poise.

4. The method for preparing a bio-based polycarbonate of claim 1, the method comprising:

(1) melting the monomer mixture and reacting the mixture under reduced pressure to produce a prepolymer; and

(2) reacting the prepolymer under reduced pressure to prepare a bio-based polycarbonate.

5. The method for preparing bio-based polycarbonate according to claim 4, wherein the above step (1) is performed at 20 mbar to 700 mbar and 140 ℃ to 220 ℃.

6. The process for preparing bio-based polycarbonate of claim 4, wherein the prepolymer has an Intrinsic Viscosity (IV) of 0.10dl/g to 0.60 dl/g.

7. The method for preparing bio-based polycarbonate according to claim 4, wherein the above step (2) is performed at 0.1 mbar to 20 mbar and 220 ℃ to 270 ℃.

8. A bio-based polycarbonate prepared by the preparation method according to any one of claims 1 to 7 and having an Intrinsic Viscosity (IV) of 0.8 to 2.3 dl/g.

9. The bio-based polycarbonate of claim 8, wherein a specimen injection molded from the bio-based polycarbonate according to ASTM D638 test method has a tensile strength of 80MPa to 200MPa and a flexural strength of 100MPa to 210 MPa.

10. The bio-based polycarbonate of claim 8, having an izod notched impact strength of 60J/m to no fracture.

11. A molded article comprising the biobased polycarbonate of claim 8.

12. The molded article of claim 11, which is an automotive part, an electrical/electronic part, a display part, an aerospace part, a mechanical part, an illumination part, a medical product, and a food container.

Technical Field

The present invention relates to biobased polycarbonates and methods for making the same. In more detail, the present invention relates to a method for preparing bio-based polycarbonate excellent in mechanical properties such as tensile strength and impact strength by using a high viscosity polycondensation reactor.

Background

Bio-based polycarbonates prepared by melt polycondensation of 1,4:3, 6-dianhydrohexitols with carbonates or dicarboxylates are bioplastics comprising bio-based monomers derived from biological sources. The bio-based polycarbonate has high transparency of PMMA (poly (methyl methacrylate)), which is a representative transparent general-purpose resin, and high heat resistance of bisphenol a (bpa) polycarbonate. In particular, in the case of using 1,4:3, 6-dianhydrohexitol as a monomer for preparing polycarbonate, which is one of representative transparent engineering plastics, the polycarbonate thus prepared has high heat resistance and transparency, as well as excellent surface hardness, UV stability, flame retardancy, and chemical resistance, and advantages of bioplastics.

In addition, ductility of the molecular structure of 1,4:3, 6-dianhydrohexitol can be improved by copolymerizing a 1, 4-cyclohexanedicarboxylate monomer having an alicyclic molecular structure. The disadvantages of carbonate linkages can also be compensated by replacing some of the carbonate linkages with ester linkages.

However, although 1,4:3, 6-dianhydrohexitol has advantages in terms of physical properties by virtue of its unique molecular structure, 1,4:3, 6-dianhydrohexitol has a disadvantage of being easily discolored at high temperature due to its relatively low oxidative stability. Therefore, if 1,4:3, 6-dianhydrohexitol is used in the melt polycondensation process at high temperature, the transparency of the product is deteriorated due to discoloration of 1,4:3, 6-dianhydrohexitol. Furthermore, if a low viscosity polymerization apparatus such as a conventional vertical stirred reactor is used, the melt viscosity of the polymer increases as the amount of 1,4:3, 6-dianhydrohexitol used increases. Commercial use thereof is limited due to difficulty in producing products having various degrees of polymerization. Therefore, in order to produce a product of high transparency and high strength while maintaining the inherent characteristics of 1,4:3, 6-dianhydrohexitol, it is necessary to ensure a polymerization apparatus and method for producing a bio-based polycarbonate having a high degree of polymerization at a low temperature for preventing discoloration of 1,4:3, 6-dianhydrohexitol.

Meanwhile, commercial methods for preparing polycarbonates may be classified into phosgene methods and non-phosgene melt polycondensation methods. Unlike the phosgene method using phosgene as a source material for carbonate ester, diphenyl carbonate (hereinafter, referred to as DPC) is used in the non-phosgene melt polycondensation method.

The non-phosgene melt polycondensation method of BPA polycarbonate uses BPA as a diol and DPC as a carbonate, and the transesterification reaction of BPA and DPC produces phenol as a by-product of melt polycondensation (see Korean patent laid-open No. 2016-0014644 and Korean patent No. 10-1221774). Further, the phosgene-free melt polycondensation process for BPA polycarbonate is generally carried out in a vertical stirring reactor, a horizontal screw reactor, a thin film evaporation reactor, a wire-wetting fall reactor, or the like. However, BPA polycarbonate produced by non-phosgene melt polycondensation at high temperature has various disadvantages such as discoloration, deterioration of physical properties, inability to produce products having various degrees of polymerization, and high production cost. Accordingly, there is a need for an apparatus and method for preparing bio-based polycarbonate on a commercial scale that can address the disadvantages described above.

Disclosure of Invention

Technical problem

Accordingly, it is an object of the present invention to provide a bio-based polycarbonate excellent in mechanical properties such as tensile strength and impact strength by using a high viscosity polycondensation reactor capable of obtaining a high degree of polymerization at low temperature while preventing discoloration and deterioration of physical properties of 1,4:3, 6-dianhydrohexitol.

Technical scheme

In order to achieve the above objects,

the present invention provides a method for preparing a bio-based polycarbonate, comprising: feeding a monomer mixture comprising at least one compound selected from the group consisting of compounds represented by the following formulae 1 to 3 and 1,4:3, 6-dianhydrohexitol to a high viscosity polycondensation reactor; and reacting them.

[ formula 1]

[ formula 2]

[ formula 3]

In the above-mentioned formula 2, the first,

R¹and R²Each being an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 18 carbon atoms,

wherein the aryl group may have at least one substituent selected from the group consisting of: an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 4 to 20 carbon atoms, an aryl group having 6 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, a cycloalkoxy group having 4 to 20 carbon atoms, an aryloxy group having 6 to 18 carbon atoms, an alkylsulfonyl group having 1 to 18 carbon atoms, a cycloalkylsulfonyl group having 4 to 20 carbon atoms, an arylsulfonyl group having 6 to 18 carbon atoms, and an ester substituent. In such cases, the ester substituent may be an alkyl ester having 1 to 18 carbon atoms, a cycloalkyl ester having 4 to 20 carbon atoms, or an aryl ester having 6 to 18 carbon atoms.

Further, the present invention provides a bio-based polycarbonate prepared by the above preparation method and having an Intrinsic Viscosity (IV) of 0.8dl/g to 2.3 dl/g.

Furthermore, the present invention provides a molded article comprising the bio-based polycarbonate.

Advantageous effects

The bio-based polycarbonate of the present invention has excellent mechanical properties such as tensile strength and impact strength and is environmentally friendly since it does not contain bisphenol.

In addition, the method of preparing the bio-based polycarbonate of the present invention using the high viscosity polycondensation reactor can prevent discoloration and deterioration of physical properties of 1,4:3, 6-dianhydrohexitol, can produce products having various degrees of polymerization, and reduce production costs.

Detailed Description

Method for preparing bio-based polycarbonate

The present invention provides a method for preparing a bio-based polycarbonate, comprising: feeding a monomer mixture comprising 1,4:3, 6-dianhydrohexitol and at least one compound selected from compounds represented by the following formulae 1 to 3 into a high viscosity polycondensation reactor and reacting them:

[ formula 1]

[ formula 2]

[ formula 3]

In the above-mentioned formula 2, the first,

R¹and R²Each being an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 18 carbon atoms,

wherein the aryl group may have at least one substituent selected from the group consisting of: an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 4 to 20 carbon atoms, an aryl group having 6 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, a cycloalkoxy group having 4 to 20 carbon atoms, an aryloxy group having 6 to 18 carbon atoms, an alkylsulfonyl group having 1 to 18 carbon atoms, a cycloalkylsulfonyl group having 4 to 20 carbon atoms, an arylsulfonyl group having 6 to 18 carbon atoms, and an ester substituent. In such cases, the ester substituent may be an alkyl ester having 1 to 18 carbon atoms, a cycloalkyl ester having 4 to 20 carbon atoms, or an aryl ester having 6 to 18 carbon atoms.

Monomer mixture

The monomer mixture includes at least one compound selected from compounds represented by the following formulas 1 to 3; and 1,4:3, 6-dianhydrohexitols.

The 1,4:3, 6-dianhydrohexitol may be at least one selected from isomannide, isosorbide, or isoidide. Specifically, the 1,4:3, 6-dianhydrohexitol may be isosorbide.

The cis/trans ratio of 1, 4-diphenyl-cyclohexanedicarboxylate (DPCD), which is a compound represented by formula 1 above, may be 1%/99% to 99%/1%, 10%/90% to 90%/10%, or 20%/80% to 80%/20%.

The compound represented by the above formula 2 may be dimethyl carbonate, diethyl carbonate, di-t-butyl carbonate, diphenyl carbonate, ditolyl carbonate, or bis (methylsalicyl) carbonate. Specifically, since the reaction is performed under reduced pressure, diphenyl carbonate or substituted diphenyl carbonate may be used as the compound represented by the above formula 2. The substituted diphenyl carbonate may be ditolyl carbonate or bis (methylsalicyl) carbonate.

The monomer mixture may include compounds represented by the following formulas 1 and 2; and 1,4:3, 6-dianhydrohexitols. Specifically, the total amount of the compound represented by the above formula 1 and the compound represented by the above formula 2 may be 0.7 mol to 1.3 mol, 0.9 mol to 1.1 mol, or 0.95mol to 1.05 mol, based on 1mol of 1,4:3, 6-dianhydrohexitol.

If the monomer mixture includes 1,4:3, 6-dianhydrohexitol and the compounds represented by formulas 1 and 2 above, the bio-based polycarbonate thus produced may include repeating unit 1 represented by formula 4 below and repeating unit 2 represented by formula 5 below.

[ formula 4]

[ formula 5]

Specifically, the repeating unit 1 may be obtained from the reaction of 1,4:3, 6-dianhydrohexitol with a carbonate-based compound represented by formula 2 above, and the repeating unit 2 may be obtained from the reaction of 1,4:3, 6-dianhydrohexitol with 1, 4-cyclohexanedicarboxylate. That is, 1,4:3, 6-dianhydrohexitol and the compound represented by formula 2 above may react to form a carbonate bond (repeating unit 1, formula 4), and 1,4:3, 6-dianhydrohexitol and the compound represented by formula 1 above may react to form an ester bond (repeating unit 2, formula 5).

Further, the cis/trans ratio of the 1, 4-cyclohexanedicarboxylate in the repeating unit 2 represented by the above formula 5 may be 1%/99% to 99%/1%, 20%/80% to 80%/20%, or 30%/70% to 70%/30%.

Meanwhile, the monomer mixture may include compounds represented by formulas 2 and 3; and 1,4:3, 6-dianhydrohexitol, wherein the compound represented by the above formula 3 is diphenyl terephthalate (DPT). Specifically, the total amount of the compound represented by the above formula 2 and the compound represented by the above formula 3 may be 0.7 mol to 1.3 mol, 0.9 mol to 1.1 mol, or 0.95mol to 1.05 mol, based on 1mol of 1,4:3, 6-dianhydrohexitol.

If the monomer mixture includes 1,4:3, 6-dianhydrohexitol and the compounds represented by formulas 2 and 3 above, the bio-based polycarbonate thus produced may include the repeating unit 1 represented by formula 4 above and the repeating unit 3 represented by formula 6 below.

[ formula 6]

Specifically, the repeating unit 1 may be obtained from the reaction of 1,4:3, 6-dianhydrohexitol with a carbonate compound represented by formula 2 above, and the repeating unit 3 may be obtained from the reaction of 1,4:3, 6-dianhydrohexitol with a terephthalate ester. That is, 1,4:3, 6-dianhydrohexitol and the compound represented by formula 2 above may react to form a carbonate bond (repeating unit 1, formula 4), and 1,4:3, 6-dianhydrohexitol and the compound represented by formula 3 above may react to form an ester bond (repeating unit 3, formula 6).

Further, the monomer mixture may include compounds represented by the following formulas 1 to 3; and 1,4:3, 6-dianhydrohexitols. Specifically, the total amount of the compound represented by the above formula 1, the compound represented by the above formula 2, and the compound represented by the above formula 3 may be 0.7 mol to 1.3 mol, 0.9 mol to 1.1 mol, or 0.95mol to 1.05 mol, based on 1mol of 1,4:3, 6-dianhydrohexitol.

If the monomer mixture includes 1,4:3, 6-dianhydrohexitol and the compounds represented by formulas 1 to 3 above, the bio-based polycarbonate thus produced may include the repeating unit 1 represented by formula 4 below, the repeating unit 2 represented by formula 5 below, and the repeating unit 3 represented by formula 6 below.

Specifically, the repeating unit 1 may be obtained from the reaction of 1,4:3, 6-dianhydrohexitol with a carbonate compound represented by formula 2 above, the repeating unit 2 may be obtained from the reaction of 1,4:3, 6-dianhydrohexitol with 1, 4-cyclohexanedicarboxylate, and the repeating unit 3 may be obtained from the reaction of 1,4:3, 6-dianhydrohexitol with terephthalate. That is, 1,4:3, 6-dianhydrohexitol and the compound represented by formula 2 above may react to form a carbonate bond (repeating unit 1, formula 4), 1,4:3, 6-dianhydrohexitol and the compound represented by formula 1 above may react to form an ester bond (repeating unit 2, formula 5), and 1,4:3, 6-dianhydrohexitol and the compound represented by formula 3 above may react to form an ester bond (repeating unit 3, formula 6).

Additives and additional monomers

The monomer mixture may further include additives such as a catalyst and a stabilizer and at least one monomer selected from another diol compound other than 1,4:3, 6-dianhydrohexitol and another ester compound other than the compounds represented by formulas 1 to 3 above.

The monomer mixture may also contain a catalyst for increasing the reactivity of the reaction. Further, the catalyst may be added to the reaction step at any time, but it is preferably added before the reaction.

Any alkali metal and/or alkaline earth metal catalyst commonly used in the melt polycondensation reaction of polycarbonate may be used as the catalyst. In addition, oxides, hydrides, amides or phenoxides of alkali metals and/or alkaline earth metals can be used as catalysts.

Examples of the alkali metal catalyst may include hydrogen hydroxideLithium (LiOH), sodium hydroxide (NaOH), potassium hydroxide (KOH), cesium hydroxide (CsOH), lithium carbonate (Li)₂CO₃) Sodium carbonate (Na)₂CO₃) Potassium carbonate (K)₂CO₃) Cesium carbonate (Cs)₂CO₃) Lithium acetate (LiOAc), sodium acetate (NaOAc), potassium acetate (KOAc), cesium acetate (CsOAc), and the like.

Examples of the alkaline earth metal catalyst may include calcium hydroxide (Ca (OH)₂) Barium hydroxide (Ba (OH)₂) Magnesium hydroxide (Mg (OH)₂) Strontium hydroxide (Sr (OH))₂) Calcium carbonate (CaCO)₃) Barium carbonate (BaCO)₃) Magnesium carbonate (MgCO)₃) Strontium carbonate (SrCO)₃) Calcium acetate (Ca (OAc)₂) Barium acetate (Ba (OAc)₂) Magnesium acetate (Mg (OAc)₂) Strontium acetate (Sr (OAc))₂) And the like.

Examples of the oxide, hydride, amide, or phenoxide of an alkali metal and/or alkaline earth metal may include magnesium oxide (MgO), barium oxide (BaO), sodium aluminate (NaAlO)₂) Zinc oxide (ZnO), lead oxide (PbO), dibutyl tin oxide ((C)₄H₉)₂SnO), antimony trioxide (Sb)₂O₃) And the like.

The catalyst may be used in such amounts: the amount is such that the metal equivalent of the catalyst is more than 0 to 5 millimoles, more than 0 to 3 millimoles, or more than 0 to 1 millimole based on 1 mole of the total diol compound. If the amount of the catalyst is within the above range, the following problems can be prevented: the degree of polymerization falls below the target degree of polymerization, and side reactions occur, whereby the target physical properties such as transparency are not satisfied.

Meanwhile, the alkali metal and/or alkaline earth metal catalyst may be used in combination with a basic catalyst such as basic ammonium or amine, basic phosphorus, or basic boron compound. The basic catalyst may be used alone or in combination, and the amount thereof is not particularly limited.

Depending on the targeted properties, the monomer mixture may also comprise further diol compounds in addition to the 1,4:3, 6-dianhydrohexitol. Specifically, the additional diol compound may have a single alicyclic or fused heterocyclic ring at the center of the molecule to improve heat resistance, transparency, UV stability and weather resistance of the bio-based polycarbonate prepared therefrom. Meanwhile, when the hydroxyl group has a symmetrical structure, the ring size and heat resistance are increased in proportion. On the other hand, the optical characteristics do not depend on the ring size and the position of the hydroxyl group, but they vary depending on the characteristics of each raw material. When the ring size is larger, it is more difficult to commercially produce and utilize the diol compound.

The additional diol compound may be a primary diol compound, a secondary diol compound, or a tertiary diol compound.

In particular, the further diol compound may be at least one diol compound selected from: 1, 2-cyclohexanedimethanol, 1, 3-cyclohexanedimethanol, 1, 4-cyclohexanedimethanol, tricyclodecanedimethanol, pentacyclopentadecane dimethanol, decalin dimethanol, tricyclotetradecane dimethanol, norbornandimethanol, adamantanedimethanol, 3, 9-bis (1, 1-dimethyl-2-hydroxyethyl) -2,4,8, 10-tetraoxaspiro [5.5] undecane, bicyclo [2.2.2] octane-2, 3-dimethanol, 2,4:3, 5-di-o-methylene-D-mannitol, tetrahydro-2, 5-furandimethanol, 5' - (1-methylethylidene) bis (2-furanmethanol), 1, 2-cyclohexanediol, 1, 3-cyclohexanediol, 1, 4-cyclohexanediol, 2-methyl-1, 4-cyclohexanediol, tricyclodecanediol, pentacyclopentadecanediol, decalinediol, tricyclotetradecanediol, norbornanediol, adamantanediol, 2-bis (4-hydroxycyclohexyl) propane and 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol. More specifically, the additional diol compound may be 1, 4-cyclohexanedimethanol, tetrahydrofuran-2, 5-dimethanol, 2, 5-furandimethanol, 2-bis (4-hydroxycyclohexyl) propane, or 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol.

When the molar amount of the additional diol compound used is p, the molar amount of the 1,4:3, 6-dianhydrohexitol used will be 1-p. In particular, if the additional diol compound is a petrochemical-based diol compound, it may be used in an amount such that the biobased carbon content (ASTM-D6866) in the final polymer derived from 1,4:3, 6-dianhydrohexitol is at least 1 mole%. In such a case, p may satisfy 0 mol. ltoreq. p <0.99 mol. That is, the additional diol compound may be used in an amount of less than 0.99 mole based on 1 mole of 1,4:3, 6-dianhydrohexitol.

The monomer mixture may further contain an additional ester compound other than the compounds represented by the above formulae 1 to 3, which are ester-bonded monomers in the polymer chain, according to the aimed characteristics.

The additional ester compound may be diphenyl ester. Further, the additional ester compound may be prepared by reacting a primary, secondary or tertiary dicarboxylate or dicarboxylic acid (hereinafter referred to as additional dicarboxylate or dicarboxylic acid) with a phenol or phenol substitute. Specifically, additional ester compounds may be prepared by reacting additional dicarboxylic acid esters or dicarboxylic acids having a single alicyclic or fused heterocyclic ring at the center of the molecule with phenol or a phenol substitute to improve heat resistance, transparency, UV stability, and weather resistance of the bio-based polycarbonate thus prepared.

Specifically, the additional ester compound may be at least one selected from the group consisting of: 1, 2-diphenyl-cyclohexanedicarboxylate, 1, 3-diphenyl-cyclohexanedicarboxylate, diphenyl decahydro-1, 4-naphthalenedicarboxylate, diphenyl decahydro-1, 5-naphthalenedicarboxylate, diphenyl decahydro-2, 4-naphthalenedicarboxylate, diphenyl decahydro-2, 5-naphthalenedicarboxylate, diphenyl decahydro-2, 6-naphthalenedicarboxylate, diphenyl decahydro-2, 7-naphthalenedicarboxylate, diphenyl decahydro-2, 8-naphthalenedicarboxylate, diphenyl tetrahydro-2, 5-furandicarboxylate, diphenyl phthalate and diphenyl isophthalate. More specifically, the additional ester compound may be 1, 3-diphenyl-cyclohexanedicarboxylate, diphenyl decahydro-2, 6-naphthalenedicarboxylate, diphenyl tetrahydro-2, 5-furandicarboxylate, diphenyl 2, 5-furandicarboxylate, or diphenyl isophthalate.

The phenol substitute used in preparing the additional ester compound may be a compound represented by the following formula 7.

[ formula 7]

In the above-mentioned formula 7, the,

R³is at least one selected from: an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 4 to 20 carbon atoms, an aryl group having 6 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, a cycloalkoxy group having 4 to 20 carbon atoms, an aryloxy group having 6 to 18 carbon atoms, an alkylsulfonyl group having 1 to 18 carbon atoms, a cycloalkylsulfonyl group having 4 to 20 carbon atoms, an arylsulfonyl group having 6 to 18 carbon atoms, or an ester substituent. In such cases, the ester substituent may be an alkyl ester having 1 to 18 carbon atoms, a cycloalkyl ester having 4 to 20 carbon atoms, or an aryl ester having 6 to 18 carbon atoms.

When the molar amount of the additional ester compound used is q, the molar amount of the compound represented by the above formulae 1 to 3 used will be 1-q. In such a case, q may satisfy 0 mol. ltoreq. q <1 mol. That is, the additional ester compound may be used in an amount of less than 1 mole based on 1 mole of the total carbonate and/or ester compound.

In addition, the monomer mixture may further include additives such as antioxidants, heat stabilizers, light absorbers, color formers, lubricants, colorants, conductive agents, nucleating agents, flame retardants, plasticizers, antistatic agents, and the like.

For example, the antioxidant can be a hindered phenol, hydroquinone, phosphite, substituted compounds thereof, and the like. Further, the light absorbing agent may be resorcinol, salicylate, or the like. Further, the color former may be phosphite, hydrogenphosphite, or the like. The lubricant may be montanic acid, stearyl alcohol, or the like. In addition, dyes and pigments may be used as the colorant. Carbon black may be used as a conductive agent or nucleating agent.

In such a case, the kinds and amounts of all the above-mentioned additives are not particularly limited as long as they do not adversely affect the physical properties, particularly transparency, of the bio-based polycarbonate thus prepared.

High viscosity polycondensation reactor

The molecular structure of BPA containing an aromatic ring reduces the free volume of the polymer chain, while 1,4:3, 6-dianhydrohexitols containing a rigid condensed heterocycle increase the free volume of the polymer chain. Thus, it is more advantageous to employ a horizontal high viscosity polycondensation reactor for the melt polycondensation process of a bio-based polycarbonate (which can be conducted at a low reaction temperature due to the low melting point of the bio-based polycarbonate) than for the polycondensation process of BPA polycarbonate which requires a high reaction temperature due to the high melt viscosity of the BPA polycarbonate for the same heat resistant composition. In addition, since the melt polycondensation reaction of the bio-based polycarbonate can be performed in a relatively low temperature range, discoloration of the product and deterioration of physical properties can be prevented. In addition, products having a high degree of polymerization without chain scission that may be caused by high shear forces induced by high agitation forces applied during melt polycondensation of BPA polycarbonate conducted in conventional low viscosity polycondensation reactors operating at high reaction temperatures may be produced.

The high viscosity polycondensation reactor may be a horizontal plug flow reactor. Specifically, the high viscosity polycondensation reactor may be a finisher (finisher reactor) including one or more stirrers, a kneader, or an extruder.

The agitator may include a shaft and screw or may be in shaftless form. The screw of the stirrer shaft may be in the form of a spiral, a lattice, a rod, a double hole (space), or the like. In particular, it may be in the form of a rod.

The high viscosity polycondensation reactor may include auxiliary equipment such as a discharge screw for discharging the final molten polymer, a vapor column for collecting phenol as a reaction by-product, a cooling trap, and a receiver. Further, in the high viscosity polycondensation reactor, the molten polymer discharged through the discharge screw is conveyed to a pelletizer to produce pellets, which may be dried and packaged.

The maximum viscosity in the high viscosity polycondensation reactor may be from 10000 poise to 1000000 poise. In particular, the maximum viscosity in the high-viscosity polycondensation reactor may be 20000 to 500000 poise or 50000 to 200000 poise. If the maximum viscosity in the high-viscosity polycondensation reactor is within the above range, a high degree of polymerization is easily achieved at a low reaction temperature.

In order to rapidly remove by-products from a molten reactant having a high viscosity and accelerate the polymerization reaction, the preparation process may be performed by increasing the temperature and reducing the pressure in a stepwise manner.

Specifically, the preparation method may include (1) melting a monomer mixture and reacting the mixture under reduced pressure to prepare a prepolymer; and (2) reacting the prepolymer under reduced pressure to prepare a bio-based polycarbonate.

Step (1)

In this step, the monomer mixture is melted and reacted under reduced pressure to prepare a prepolymer.

This step may be performed in a reactor that includes auxiliary equipment such as a vacuum pump for reducing pressure, a vapor column for collecting phenol as a reaction byproduct, a cooling trap, and a receiver.

The Intrinsic Viscosity (IV) of the prepolymer may be from 0.10dl/g to 0.60 dl/g. Specifically, the Intrinsic Viscosity (IV) of the prepolymer may be 0.20dl/g to 0.55dl/g or 0.30dl/g to 0.50 dl/g.

In particular, this step can be carried out at from 20 mbar to 700 mbar and from 140 ℃ to 220 ℃.

In particular, this step may comprise (i) melting the monomer mixture, then increasing the temperature to 140 ℃ to 180 ℃ and reducing the pressure to 300 mbar to 700 mbar; and (ii) increasing the temperature to 180 ℃ to 220 ℃ and reducing the pressure to 20 mbar to 300 mbar. More specifically, this step may include (i) melting the monomer mixture, then increasing the temperature to 150 ℃ to 180 ℃ or 160 ℃ to 180 ℃, and reducing the pressure to 300 mbar to 650 mbar or 300 mbar to 600 mbar; and (ii) increasing the temperature to 190 ℃ to 220 ℃ or 200 ℃ to 220 ℃, and reducing the pressure to 20 mbar to 250 mbar or 20 mbar to 200 mbar.

Step (2)

In this step, the prepolymer is reacted under reduced pressure to prepare a bio-based polycarbonate.

In particular, this step can be carried out at from 0.1 mbar to 20 mbar and from 220 ℃ to 270 ℃.

In particular, this step may comprise (i) increasing the temperature of the prepolymer to 220 ℃ to 240 ℃ and reducing the pressure to 5 mbar to 20 mbar; and (ii) increasing the temperature to 240 ℃ to 270 ℃ and reducing the pressure to 0.1 mbar to 5 mbar. In particular, this step may comprise (i) increasing the temperature of the prepolymer to 220 ℃ to 240 ℃ and reducing the pressure to 5 mbar to 15 mbar or 5 mbar to 10 mbar; and (ii) increasing the temperature to 240 ℃ to 270 ℃ and reducing the pressure to 0.1 mbar to 3 mbar or 0.1 mbar to 1 mbar.

The temperature rise rate in this step may be 0.1 to 10, 0.2 to 5, or 0.5 to 2 ℃/min. Further, the reaction time may be 1 hour to 10 hours or 3 hours to 8 hours.

Meanwhile, when the melt polycondensation reaction is performed, phenol may be generated as a reaction by-product. Phenol produced as a by-product is preferably removed from the reaction system to shift the reaction equilibrium toward the production of polycarbonate. If the temperature rising rate in the melt polycondensation reaction is in the above range, the problem of evaporation or sublimation of phenol (reaction by-product) together with the reaction raw material can be prevented.

Further, the method for preparing the bio-based polycarbonate may be a batch method or a continuous method. Specifically, the above steps (1) and (2) may be carried out in the same reactor or may be carried out in different reactors, respectively.

If the above steps (1) and (2) are carried out in different reactors, the above step (1) can be carried out in a reactor (e.g., a vertical stirring reactor, a thin film evaporation reactor, a wire wetting fall reactor, etc.) that can be used in conventional processes for producing BPA polycarbonate on a commercial scale. Thereafter, the prepolymer prepared in the above step (1) is continuously fed to a high viscosity polycondensation reactor in which the above step (2) is carried out. The feed rate to the high viscosity polycondensation reactor may vary depending on the molecular weight of the prepolymer produced.

Further, if the above steps (1) and (2) are carried out in the same reactor, the reactor may be a high-viscosity polycondensation reactor.

Bio-based polycarbonate

The present invention provides a bio-based polycarbonate prepared by the above preparation method and having an Intrinsic Viscosity (IV) of 0.8dl/g to 2.3 dl/g.

Specifically, the Intrinsic Viscosity (IV) of the bio-based polycarbonate may be 0.8dl/g to 2.0dl/g, 0.8dl/g to 1.7dl/g, or 0.8dl/g to 1.4 dl/g.

A specimen injection molded from the bio-based polycarbonate according to ASTM D638 test method may have a tensile strength of 80MPa to 200MPa and a flexural strength of 100MPa to 210 MPa. Specifically, the sample may have a tensile strength of 80MPa to 190MPa, 80MPa to 180MPa, or 80MPa to 170MPa and a flexural strength of 100MPa to 200MPa, 100MPa to 190MPa, or 100MPa to 180 MPa.

The bio-based polycarbonate may have an Izod notched impact strength (Izod notch impact strength) of 60J/m to no fracture (NB). Specifically, the notched izod impact strength of the bio-based polycarbonate can be 70J/m to No Break (NB), 80J/m to No Break (NB), or 90J/m to No Break (NB). Here, the absence of breakage means that the test piece is not broken since the test piece has an impact strength exceeding the measurement limit of the impact tester.

Molded article

Furthermore, the present invention provides a molded article comprising the bio-based polycarbonate. In particular, the molded article may be produced by molding a bio-based polycarbonate.

The molding method is not particularly limited. For example, injection molding, extrusion molding, blow molding, extrusion blow molding, inflation molding, calender molding, foam molding, balloon molding (balloon molding), vacuum molding, and radiation molding may be employed.

The use of the molded article is not particularly limited. The molded article can be used as a substitute for conventional heat-resistant articles and optical articles by virtue of its excellent heat resistance and transparency. Specifically, the molded article may be an automobile part, an electric/electronic part, a lighting part, a medical product, a display part, an aviation part, a mechanical part, and a food container.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention is described in more detail by the following examples and comparative examples. However, these examples are provided for illustrative purposes only, and the present invention is not limited thereto.

[ examples of embodiments]Preparation of high viscosity bio-based polycarbonate