CN113321796B - High-transparency high-heat-resistance copolyester resin and preparation method thereof - Google Patents
High-transparency high-heat-resistance copolyester resin and preparation method thereof Download PDFInfo
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- CN113321796B CN113321796B CN202110578053.1A CN202110578053A CN113321796B CN 113321796 B CN113321796 B CN 113321796B CN 202110578053 A CN202110578053 A CN 202110578053A CN 113321796 B CN113321796 B CN 113321796B
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
- C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
- C08G63/16—Dicarboxylic acids and dihydroxy compounds
- C08G63/18—Dicarboxylic acids and dihydroxy compounds the acids or hydroxy compounds containing carbocyclic rings
- C08G63/199—Acids or hydroxy compounds containing cycloaliphatic rings
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/78—Preparation processes
Abstract
The invention relates to a polyester high molecular material, and discloses a high-transparency high-heat-resistance copolyester resin and a preparation method thereof, wherein the copolyester resin comprises the following components: (1) the dibasic acid component comprises: (a)80 to 100 mole% of terephthalic acid residues; and (b)0 to 20 mol% of aromatic dibasic acid residues; and (2) the glycol component comprises: (a)20 to 85 mole% of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol residues; and (b)15 to 80 mole% of a first diol residue; and (c)0 to 30 mole% of a second diol residue; the copolyester resin disclosed by the invention is beneficial to avoiding blockage, improving the characteristic viscosity number and inhibiting the loss of CBDO monomers in the preparation process by introducing the pentanediol residue or the propylene glycol residue, has high glass transition temperature and excellent strength, toughness and thermal stability, and can effectively inhibit foaming, foaming and expansion phenomena caused by thermal decomposition in the melt processing process.
Description
Technical Field
The invention relates to a polyester high polymer material, in particular to a high-transparency high-heat-resistance copolyester resin and a preparation method thereof.
Background
Polycarbonate (PC) based on bisphenol a is the most commonly used high-transparency high-heat-resistant polymer material. PC has excellent transparency, heat resistance and toughness, the light transmittance of the PC is more than 90 percent, the glass transition temperature of the PC is about 150 ℃, the PC can be used for a long time at 120 ℃, and the PC is an important engineering plastic and is also commonly used for water cups, feeding bottles and household utensils. Since PC releases bisphenol a (BPA) at high temperatures and BPA is absorbed by the human body to cause endocrine disorders, PC is concerned about safety and is prohibited from being used in food contact products such as milk bottles.
In 2007, eastman corporation, usa developed 2,2,4, 4-tetramethyl-1, 3-Cyclobutanediol (CBDO) which is a high steric hindrance diol monomer, and the high transparency and high heat resistance copolyester is prepared by copolycondensating CBDO with 1, 4-Cyclohexanedimethanol (CHDM) and dimethyl terephthalate, and is also called as Tritan (PCcBT) copolyester in the invention) and is used as a substitute for PC. The Tritan copolyester has the glass transition temperature of about 120 ℃ at most, has the characteristics of high transparency, high heat resistance, high toughness, no BPA release and high temperature resistance of 100 ℃ in part of brands, and can be used as a baby feeding bottle.
However, as safe high-transparency high-heat-resistant polymer materials, Tritan copolyester resin and other high-transparency high-heat-resistant copolyesters using CBDO as a high-steric hindrance monomer still have the following technical problems in their manufacture, processing and application.
(1) The heat resistance is low. Currently, the Tg of Tritan copolyester products is up to about 120 ℃ which is significantly lower than 150 ℃ for PC; the heat distortion temperature is only 109 ℃ at the most.
(2) The thermal stability is insufficient, and during high-temperature processes such as melt polycondensation and melt processing, copolyester is easy to decompose, gas is generated, expansion is generated, and normal operation of reaction and processing is influenced. For example, chinese patent publication CN101300285A mentions that the melt level is very unstable without adding a stabilizer, excessive foaming and foaming result in high porosity of the melt, and the melt interface rises rapidly and easily overflows from the flask without stirring or at a low stirring speed. Even with the addition of stabilizers, a stable melt level and limited gas evolution are maintained only at the proper catalyst/stabilizer ratio; chinese patent publication CN104736600A mentions that CHDM residues and CBDO residues decompose to generate volatile components of carbon monoxide and carbon dioxide during high temperature film extrusion, making venting difficult and processing difficult, and the resulting sheet has trumpet-shaped defects.
(3) The CHDM and the CBDO are both solid at room temperature, wherein the CBDO has high melting point and boiling point, is easy to sublimate, has low solubility in CHDM melt, is easy to block pipelines and equipment in the polymerization and recovery processes, and has potential safety hazard; the industry needs additional insulation of the pipes and equipment to prevent clogging, resulting in increased production costs and energy consumption.
(4) CBDO is easy to lose due to sublimation or side reaction in the polymerization process, and CBDO, especially trans-CBDO cannot enter the copolyester structure completely, so that the content of CBDO residues in the copolyester (namely, the composition of the copolymer) is obviously lower than that of CBDO in a dihydric alcohol monomer (namely, the composition of the monomer). For example, in chinese patent publication CN101193938A, when CBDO is dosed in an amount of 30 mol% of the total amount of diol, the CBDO residues in the final polymer account for only 20 mol% or even less of the total amount of diol residues. In chinese patent publication No. CN104736600A, the cis-trans ratio of the added CBDO monomer is 53/47 at high polycondensation temperature, while the cis-trans ratio of the CBDO residues in the resulting copolyester becomes 70/30, which deviates to 60/40 even at lower temperatures. In the chinese patent publication CN104736600A, the cis-inverse ratio of CBDO residues of the obtained copolyester is deviated from the cis-inverse ratio of CBDO of the monomer to a different degree, for example, when the cis-inverse ratio of CBDO monomer is 50/50, the cis-inverse ratio of CBDO residues of the obtained copolyester is 51.4/48.6 to 54.0/46.0.
(5) In the reaction process, a copolymer rich in poly (1, 4-cyclohexylenedimethylene terephthalate) (PCT) chain segments, even a PCT homopolymer, which has a high melting point and is easy to crystallize and precipitate, is easy to generate, so that the molecular weight and the transparency of the product are obviously reduced, and the precipitated PCT can pollute equipment. To avoid the generation of precipitates, chinese patent publication CN103755930A uses a reaction temperature of 280 ℃ or higher, but the high temperature will aggravate the thermal decomposition of CBDO and CHDM monomers and products, generating chromophore, and producing colored and low molecular weight products. Chinese patent publication CN101379619A proposes a method of stepwise transesterification to solve the above problems, i.e. after dimethyl terephthalate reacts with all or part of CBDO to form polyester oligomer, it reacts with all or part of CHDM to obtain oligomer, which is further polymerized to obtain polymer with high molecular weight. This staged addition reaction process can reduce precipitation of PCT, but still cannot be completely avoided and increases process costs.
(6) Copolyesters are prone to discoloration during polycondensation and processing. Chinese patent publication CN101300285A mentions that Tritan copolyester is liable to have a yellow color, and even if a stabilizer is added, a pale yellow product may be obtained.
Therefore, how to obtain the high-transparency high-heat-resistance copolyester with higher heat resistance and thermal stability based on CBDO, how to obtain a polymerization method and a polymerization process which can avoid CBDO blockage, improve controllability of copolymer composition and cis-inverse ratio, inhibit color change and avoid generation of precipitates at lower reaction temperature, and still remain technical problems to be solved in the fields of high-transparency high-heat-resistance copolyester products and preparation methods thereof.
Disclosure of Invention
The invention aims to solve the problems that the copolyester based on CBDO has poor thermal stability, is easy to sublimate to generate gas and block pipeline equipment, has poor transparency and is easy to discolor in the prior art, and provides the copolyester based on terephthalic acid, dimethyl terephthalate and CBDO monomers, which has excellent thermal stability and mechanical strength, high transparency and difficult discoloration.
In order to realize the purpose, the invention adopts the technical scheme that:
a high-transparency high-heat-resistance copolyester resin comprises the following components:
(1) a dibasic acid component comprising, in a total amount of 100 mol%:
(a)80 to 100 mol% of terephthalic acid residues; and
(b)0 to 20 mol% of an aromatic dibasic acid residue;
and
(2) a glycol component comprising, based on 100 mol% of the total:
(a)20 to 85 mol% of 2,2,4, 4-tetramethyl-1, 3-Cyclobutanediol (CBDO) residues; and
(b)15 to 80 mol% of a first diol residue; and
(c)0 to 30 mol% of a second glycol residue;
the aromatic dibasic acid residue comprises at least one of isophthalic acid residue, phthalic acid residue, biphenyl dicarboxylic acid residue, naphthalene dicarboxylic acid residue, furan dicarboxylic acid residue and thiophene dicarboxylic acid residue;
the first dihydric alcohol residue comprises at least one of 1, 5-pentanediol residue, 2-methyl-1, 5-pentanediol residue, 3-methyl 1, 5-pentanediol residue, 2-ethyl-1, 5-pentanediol residue, 3-dimethyl-1, 5-pentanediol residue, 3-diethyl-1, 5-pentanediol residue, 2-methyl-1, 3-propanediol residue, 2-ethyl-1, 3-propanediol residue;
the second diol residue comprises at least one of an aliphatic diol residue with the main chain carbon atom number less than or equal to 4 or an alicyclic or heterocyclic diol residue with the carbon atom number less than or equal to 12.
Because the 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol residue chain segment has stronger rigidity, higher glass transition temperature and poorer toughness, the toughness of the copolyester is improved by introducing the chain segment containing pentanediol residue or propylene glycol residue into the copolyester, and the copolyester with better glass transition temperature and toughness is obtained by regulating the proportion of the chain segment.
The copolymer composition of the copolyester and the forward and inverse controllability of CBDO residues are high, pipelines and equipment blockage caused by volatilization and condensation of CBDO monomers can be avoided in the preparation process, and the foaming, foaming and expansion phenomena of the obtained copolyester resin in the melt processing process are effectively inhibited.
When the content of CBDO residues is too high, the characteristic viscosity of the copolyester is difficult to improve due to too much rigid structure, and the thermal property and the mechanical property of the copolyester are further influenced; and the content of the residue chain segment of the pentanediol or the propanediol is too high, the glass transition temperature of the copolyester can be greatly reduced, and the application of the copolyester is limited.
Preferably, the diol component, in a total of 100 mol%, comprises:
(a) 50-80 mol% of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol residues; and
(b)20 to 50 mol% of a first dihydric alcohol residue; and
(c)0 to 30 mol% of a second glycol residue.
Further preferably, the copolyester resin comprises the following components:
(1) a dibasic acid component comprising, in a total amount of 100 mol%:
(a)100 mole% of terephthalic acid residues;
and
(2) a glycol component comprising, based on 100 mol% of the total:
(a) 50-80 mol% of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol residues; and
(b)20 to 50 mol% of a first dihydric alcohol residue.
The molar ratio of the dibasic acid component to the glycol component is 1:1-1:3, preferably 1: 1.1-1: 2, and more preferably 1: 1.1-1: 1.5.
Further preferably, the aromatic dibasic acid residues include isophthalic acid residues and/or phthalic acid residues.
Further preferably, the first dihydric alcohol residue comprises at least one of a 1, 5-pentanediol residue, a 3-methyl-1, 5-pentanediol residue, a 2-methyl-1, 3-propanediol residue, a 2-ethyl-1, 5-pentanediol residue, a 3-ethyl-1, 5-pentanediol residue;
further preferably, the first diol residue comprises at least one of a 1, 5-pentanediol residue, a 3-methyl-1, 5-pentanediol residue, a 2-methyl-1, 3-propanediol residue;
most preferably, the first dihydric alcohol residue is a 2-methyl-1, 3-propanediol residue;
the aliphatic diol residue with the main chain carbon atom number less than or equal to 4 comprises at least one of ethylene glycol residue, 1, 3-propylene glycol residue, 1, 4-butanediol residue, 2, 3-butanediol residue and 1, 2-propylene glycol residue;
the alicyclic or heterocyclic diol residue with the carbon number less than or equal to 12 comprises at least one of 1, 4-cyclohexanedimethanol residue and cyclohexanediol residue.
The intrinsic viscosity of the copolyester resin is 0.53-0.90dL/g, and the intrinsic viscosity is measured at 25 ℃ by using 3/2wt/wt phenol/tetrachloroethane as a solvent. The copolyester provided by the invention has high intrinsic viscosity which is more than or equal to 0.60dL/g and up to 0.90dL/g in most cases, and can effectively inhibit the thermal degradation of raw materials and intermediate products, so that the obtained copolyester has light color.
The intrinsic viscosity of the copolyester resin is preferably 0.59-0.80 dL/g, and more preferably 0.60-0.75 dL/g.
The glass transition temperature (Tg) of the copolyester resin can be adjusted in a wide range (60-150 ℃), and even if the glass transition temperature is lower under the same CBDO content, the copolyester with high Tg can be prepared by increasing the content of CBDO chain links. The glass transition temperature of the copolyester resin is similar to or higher than that of the conventional copolyester in the prior art (110 ℃), so that the copolyester resin has higher Young modulus, tensile strength and ductility and better mechanical property.
The glass transition temperature of the copolyester resin is preferably 80-140 ℃, and more preferably 100-136 ℃.
In the prior art, because CBDO has a cyclic large steric hindrance structure and the hydroxyl group of CBDO is connected with secondary carbon, the reactivity of CBDO with acid or ester is obviously lower than that of the first dihydric alcohol. With increasing CBDO content, the molecular weight of the copolyester is more difficult to increase. In order to obtain high intrinsic viscosity, the prior art often adopts high (more than or equal to 280 ℃) polycondensation reaction temperature. However, higher polymerization temperatures further exacerbate the sublimation of CBDO and copolyester products, resulting in further aggravated line plugging.
The invention also provides a preparation method of the high-transparency high-heat-resistance copolyester resin, which can achieve high characteristic viscosity at the reaction temperature of lower than 280 ℃, can efficiently avoid CBDO blockage, efficiently reduce the composition difference and the cis-inverse ratio difference of the copolymer composition and the monomer, efficiently avoid the generation of opaque products, and efficiently inhibit the discoloration of the products, and comprises the following steps:
(1) carrying out esterification or ester exchange reaction on a mixture containing a dibasic acid component and a dihydric alcohol component at 200-250 ℃ to obtain an intermediate product;
(2) polycondensing the intermediate product at a pressure of 10-200Pa and a temperature of 250-270 ℃ to obtain the copolyester resin;
the mixture comprises the following components:
(1) a dibasic acid component comprising, in a total amount of 100 mol%:
(a)80 to 100 mol% of terephthalic acid or dimethyl ester thereof; and
(b)0 to 20 mol% of an aromatic dibasic acid or its dimethyl ester;
and
(2) a glycol component comprising, based on 100 mol% of the total:
(a)20-85 mol% of 2,2,4, 4-tetramethyl-1, 3-Cyclobutanediol (CBDO); and
(b)15-80 mol% of a first glycol; and
(c)0 to 30 mol% of a second glycol;
the aromatic dibasic acid or the dimethyl ester thereof comprises at least one of isophthalic acid or the dimethyl ester thereof, phthalic acid or the dimethyl ester thereof, biphenyl dicarboxylic acid or the dimethyl ester thereof, naphthalene dicarboxylic acid or the dimethyl ester thereof, furan dicarboxylic acid or the dimethyl ester thereof, and thiophene dicarboxylic acid or the dimethyl ester thereof;
the first dihydric alcohol comprises at least one of 1, 5-pentanediol, 2-methyl-1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 2-ethyl-1, 5-pentanediol, 3-dimethyl-1, 5-pentanediol, 3-diethyl-1, 5-pentanediol, 2-methyl-1, 3-propanediol, 2-ethyl-1, 3-propanediol;
the second dihydric alcohol comprises at least one of aliphatic dihydric alcohol with the carbon atom number of the main chain less than or equal to 4 or alicyclic or heterocyclic dihydric alcohol with the carbon atom number less than or equal to 12.
Preferably, the diol component, in a total of 100 mol%, comprises:
(a) 50-80 mol% of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol; and
(b)20 to 50 mol% of a first dihydric alcohol; and
(c)0 to 30 mol% of a second glycol.
Further preferably, the copolyester resin comprises the following components:
(1) a dibasic acid component comprising, in a total amount of 100 mol%:
(a)100 mol% of terephthalic acid or its dimethyl ester;
and
(2) a glycol component comprising, based on 100 mol% of the total:
(a) 50-80 mol% of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol; and
(b)20 to 50 mol% of a first dihydric alcohol.
Further preferably, the aromatic dibasic acid or its dimethyl ester comprises isophthalic acid or its dimethyl ester and/or phthalic acid or its dimethyl ester.
Further preferably, the first dihydric alcohol comprises at least one of 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 2-methyl-1, 3-propanediol, 2-ethyl-1, 5-pentanediol, 3-ethyl-1, 5-pentanediol;
further preferably, the first dihydric alcohol comprises at least one of 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 2-methyl-1, 3-propanediol;
most preferably, the first dihydric alcohol is 2-methyl-1, 3-propanediol;
preferably, the aliphatic diol with the carbon atom number of the main chain being less than or equal to 4 comprises at least one of ethylene glycol, 1, 3-propanediol, 1, 2-propanediol, 1, 4-butanediol, 2, 3-butanediol, 1, 2-pentanediol and 1, 4-pentanediol;
the alicyclic or heterocyclic diol with the carbon number less than or equal to 12 comprises at least one of 1, 4-cyclohexanedimethanol and cyclohexanediol.
CBDO is a key monomer of the high-transparency high-heat-resistance copolyester and is also key to controlling the cost of the copolyester, so that the CBDO monomer which is input is expected to be completely or possibly introduced into the structure of the copolyester chain, and the loss and the recovery load of the CBDO monomer are reduced. However, in practice, because of losses caused by side reactions (especially the trans-form CBDO is more susceptible to side reactions), volatilization, sublimation, etc., the content of CBDO residues in the copolyester is often significantly lower than the content of CBDO added to the diol monomer, and the content of cis CBDO residues in the copolyester is significantly higher than the cis CBDO content in the monomer, which have deviations. These deviations are desired to be minimized in the industry, which reduces the CBDO monomer loss and recovery load, and also improves the overall properties of the resulting copolyester.
The composition deviation, the relative composition deviation, the cis deviation and the cis relative deviation of the copolyester are obviously lower than those of the copolyester in the market, and the copolyester has obvious advantages in the aspects of avoiding the side reaction and loss of CBDO and introducing the input CBDO into the copolyester as much as possible.
In the copolyester resin, a polyester resin and a polyester resin,
the difference between the molar percentage of CBDO residues in the diol residues and the molar percentage of CBDO monomers in the diol monomers is less than or equal to 8 mol%; preferably, the difference is 6 mol% or less, more preferably 3 mol% or less;
the difference between the ratio of the cis-CBDO residue in the CBDO residue and the ratio of the cis-CBDO monomer in the CBDO monomer is less than or equal to 8%, preferably, the difference between the two is less than or equal to 3%, more preferably, less than or equal to 2%.
The mixture also comprises a catalyst, a heat stabilizer and a light stabilizer;
the dosage of the catalyst is less than 1 wt% of the weight of the dibasic acid component;
the using amount of the heat stabilizer is 0.1-1 wt% of the weight of the dibasic acid component;
the using amount of the light stabilizer is less than 1 wt% of the mass of the dibasic acid component.
The catalyst comprises a tin-based catalyst; or comprises tin catalyst and one or more of tetrabutyl titanate, isopropyl titanate, lithium acetate, potassium acetate, calcium acetate, magnesium acetate, barium acetate, zinc acetate, cobalt acetate, antimony acetate, lead acetate and manganese acetate;
the tin catalyst is one or more selected from dibutyltin oxide, stannous octoate, stannous oxalate, dibutyltin diacetate and dibutyltin dilaurate.
The heat stabilizer is selected from the group consisting of heat stabilizer 1010, heat stabilizer 1500, heat stabilizer 1076, heat stabilizer 425, heat stabilizer 330, heat stabilizer 1178, heat stabilizer 501, heat stabilizer 618, heat stabilizer 626, heat stabilizer 168, TDD, trimethyl phosphite, triethyl phosphite, triisooctyl phosphite, triisodecyl phosphite, trilauryl phosphite, tridecyl phosphite, trioctadecyl phosphite, triphenyl phosphite, tri-p-tolyl phosphite, ditridecyl phosphite, tris (2, 4-di-tert-butylphenyl) phosphite, pentaerythritol bis (2, 4-tert-butylphenyl) diphosphite, bis (2, 4-di-p-isopropylphenyl) pentaerythritol diphosphite phosphoric acid, pentaerythritol tetrapolyphenyl tridecyl phosphite, pentaerythritol diphosphite, pentaerythritol diisodecyl phosphite, pentaerythritol diphosphite, heat stabilizer 1178, heat stabilizer 501, heat stabilizer 626, heat stabilizer 168, TDD, trimethyl phosphite, triethyl phosphite, triisooctyl phosphite, triisodecyl phosphite, tristearin, tritolyl phosphite, pentaerythritol diphosphearin, ditertilizer, and pentaerythritol diphosphonite, One or more of pentaerythritol dioctadecyl phosphite, phosphoric acid, phosphorous acid, polyphosphoric acid and triethyl phosphonoacetate.
The light stabilizer is selected from one or more of light stabilizer 791, light stabilizer 700, light stabilizer 783, light stabilizer 119, light stabilizer 770, light stabilizer 622, light stabilizer 944, light stabilizer 1164, 2,2,6, 6-tetramethyl-4-piperidine stearate, bis (2,2,6, 6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6, 6-pentamethyl-4-piperidyl) sebacate, 2-hydroxy-4-n-octyloxybenzophenone, (3, 5-di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole and poly (1-hydroxyethyl, yl-2, 2,6, 6-tetramethyl-4-hydroxypiperidine) succinate.
Preferably, the heat stabilizer comprises at least one of heat stabilizer 1010, heat stabilizer 1500, and heat stabilizer 626;
preferably, the light stabilizer includes at least one of light stabilizer 700, light stabilizer 783, and light stabilizer 119.
Compared with the prior art, the invention has the following beneficial effects:
(1) the copolyester resin provided by the invention has the advantages that the toughness of the copolyester is improved by introducing chain segments containing pentanediol residues or propylene glycol residues, so that the copolyester resin with excellent comprehensive performance is obtained, the glass transition temperature of the copolyester resin can be adjusted within the range of 85-150 ℃, and the heat resistance is good; meanwhile, the high-temperature melt polycondensation agent has excellent thermal stability, is beneficial to improving the characteristic viscosity number in the high-temperature polycondensation process, can effectively avoid foaming, foaming and expansion phenomena caused by thermal decomposition in the melt processing process, and obviously improves the processability; the product also has excellent strength and toughness, the tensile strength is not lower than 37MPa, and the elongation at break is not lower than 25%.
(2) The copolyester resin CBDO can be dissolved in a monomer containing pentanediol or propanediol, and can prepare copolyester with high characteristic viscosity at a lower temperature, and simultaneously, the thermal degradation of raw materials and intermediate products is effectively inhibited, and the obtained copolyester is light in color; meanwhile, pipeline and equipment blockage caused by volatilization and condensation of the CBDO monomer in the preparation process is avoided, and foaming, foaming and expansion phenomena of the obtained copolyester resin in the melt processing process are effectively inhibited.
(3) According to the preparation method of the copolyester resin, the input CBDO monomer is introduced into the copolyester chain structure as much as possible, and the cis-inverse ratio of the CBDO residue in the polyester is closer to the cis-inverse ratio of the CBDO monomer, so that the consumption and the recovery load of the CBDO monomer can be reduced, and the cost is further reduced.
In conclusion, the high-transparency high-heat-resistance copolyester provided by the invention has excellent comprehensive performance, and the preparation process can effectively solve the technical problems of blockage, thermal decomposition, color change, composition, forward and reverse ratio regulation and control and the like, and is favorable for realizing large-scale production.
Drawings
FIG. 1 is a graph showing the occurrence of clogging of piping and receiver bottles in the synthesis process of comparative example 2.
FIG. 2 is a diagram showing that the piping and receiver flask were not clogged during the synthesis of example 2.
FIG. 3 is a diagram showing how the copolyesters prepared in comparative example 1, example 1 and example 2 are foamed by heating at 240 ℃ for 5 hours in a flask and then cooling to room temperature, (a) is comparative example 1, (b) is example 1, and (c) is example 2.
FIG. 4 shows the samples of the sheet obtained by molding comparative example 1 and example 5, wherein (a) is comparative example 1 and (b) is example 5.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Those skilled in the art should understand that they can make modifications and equivalents without departing from the spirit and scope of the present invention, and all such modifications and equivalents are intended to be included within the scope of the present invention.
The raw materials used in the following specific embodiments are all commercially available.
In the following embodiments, the names, acronyms, and abbreviations for the monomer residues of the diacids and diols used are shown in table 1. Is composed of monomers
Expressed in physical terms as the percentage of the amount of material of monomer x to the sum of the amounts of material of all diol or diacid monomers. If cis-trans isomerism exists, the cis content of the monomer is as follows
Expressed in the physical sense of the molar percentage of cis-monomer x relative to the total amount of the monomer (including cis and trans). For example, for the diol monomer CBDO,
representing the mole percent of CBDO to all diol monomers,
represents the molar percentage of cis-CBDO to the total amount of CBDO (including both cis-CBDO and trans-CBDO).
TABLE 1 summary of the names and abbreviations of the monomers used in the examples
| Name of monomer | Abbreviation for monomer | Abbreviation for monomer residue |
| Terephthalic acid, dimethyl terephthalate | TPA，DMT | T |
| 2,2,2, 4-tetramethyl-1, 3-cyclobutanediol | CBDO | cB |
| 1, 5-pentanediol | PeDO | Pe |
| 3-methyl-1, 5-pentanediol | mPeDO | mPe |
| 2-methyl-1, 3-propanediol | mPDO | mP |
| Ethylene glycol | EG | E |
| 1, 4-cyclohexanedimethanol | CHDM | C |
In the following embodiments, the copolyesters produced are represented by PXY, where X is an abbreviation for all diol residues and Y is an abbreviation for all diacid residues. The subscript of the residue indicates the copolymer composition, i.e., the percentage of the amount of material of that residue to the sum of the amounts of material of the diol residue or diacid residue; the presence of residue X in the copolyester indicates the presence of cis-trans isomerism of the residue, and the superscript indicates the molar percentage of cis-residues φ cis,X I.e., the percentage of the amount of material of the cis residue to the sum of the amounts of material of the residue (including cis and trans). For example,
showing a copolyester comprising ethylene glycol residues (E), 1, 5-pentanediol residues (Pe), 2,4, 4-tetramethyl-1, 3-cyclobutanediol residues (cB) and terephthalic acid residues (T), wherein the contents of E residues, Pe residues and cB residues in the diol residues (phi) E 、φ Pe 、φ cB ) 9 mol%, 27 mol% and 64 mol%, respectively, of the cB residues, the cis cB residue represents 62 mol% of the total cB residues (including cis and trans). For the copolyester, phi cB 64 mol% denotes the copolymer composition,. phi. cis,cB 62 mol% indicates the content (molar percentage) of cis-cB residues. In addition, for the sake of simplicity, only the copolymerization with two alcohols is indicatedThe content of one alcohol residue, the content of the other alcohol residue can be obtained in an obvious way and is therefore not redundantly labeled. For example,
the content of cB residues is 34%, and the content of mPe residues is 66% to 100%.
In the following embodiments, the apparent esterification ratio or the apparent ester exchange ratio is described as follows: in the preparation of polyesters by the esterification-polycondensation or transesterification-polycondensation process, the esterification rate or transesterification rate is generally determined as the percentage of the amount of by-product water or methanol collected to the theoretical yield of water or methanol. However, during the esterification-polycondensation or transesterification-polycondensation reaction in which CBDO is involved, low-boiling by-products (e.g., aldehydes) formed can enter the distillate collection bottle with water or methanol due to the presence of undesirable side reactions. The esterification rate or ester exchange rate calculated by using all fractions as water or methanol is referred to as an apparent esterification rate or an apparent ester exchange rate. They are numerically larger than the true esterification or transesterification rate, but the extent to which the esterification or transesterification reaction proceeds can still be roughly estimated from their size.
In the following specific embodiment, the test analysis method used is as follows:
characteristic viscosity number: the characteristic viscosity (IV) of the copolyester sample is measured by a Hangzhou Zhongwang automatic viscometer, the measuring temperature is 25 ℃, and the solvent is phenol/tetrachloroethane (the mass ratio w/w is 3/2);
and (3) characterizing a chemical structure: the chemical structure of the copolyester is characterized by a Bruker AC-80400M nuclear magnetic resonance instrument, deuterated chloroform is used as a solvent, and tetramethylsilane is used as an internal standard;
thermal properties: adopting a DSC curve of a sample measured by Q200 of American TA company, adopting a temperature program of primary heating-cooling-secondary heating, wherein the test temperature range is room temperature-250 ℃, the heating and cooling rates are 10 ℃/min, and the isothermal time is 3 min;
tensile property: dumbbell-shaped sample bars 4mm wide and 2mm thick were prepared using a HaakeMinijet 11 mini-injection molding machine and measured after being left at room temperature for 1 week. Tensile testing was carried out at 25 ℃ and a tensile rate of 10mm/min according to ASTM D638 using a Roell 2020 Universal Material tester from Zwick, Germany. Each sample is tested with 5 splines, and the average value is taken as the test result;
comparative example 1
Synthesis of (2)
(1) To N 2 An atmospheric reactor was charged with 67.96g (0.35mol) of dimethyl terephthalate, 29.53g (0.20mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol (cis content 45%), 36.09g (0.25mol, cis content 26%) of 1, 4-cyclohexanedimethanol and 0.2039g of dibutyltin oxide, and 10100.068g of a main stabilizer and 6260.034 g of an auxiliary stabilizer were added to react at 220 ℃ for 2.5 hours to obtain an ester-exchanged product. During the reaction, a small amount of solid sublimed and remained in the subsequent line, but did not block the line.
(2) Polycondensing the ester exchange product for 2.5h at 260 ℃ under the absolute pressure of less than or equal to 200Pa to obtain the product with the intrinsic viscosity of 0.69dL/g and phi cB 35.4 mol%, phi cis,cB 50.4 mol%, phi C 64.6 mol%, phi cis,C 29.7 mol% of copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-1, 4-cyclohexanedimethanol terephthalate), described
In the reaction process, a large amount of solid is pumped out of the reactor, a pipeline is seriously blocked, and the system is difficult to maintain at a high vacuum degree; the temperature of the pipeline is increased by heating the pipeline, so that the pipeline is dredged, and the reaction is continued under high vacuum degree. Furthermore, after 0.5h of reaction, the melt level in the reaction began to be unable to maintain a steady state, unstable evolution of gas, severe foaming and foaming resulted in high void volumes, and it was necessary to break the foam and bubble by stirring to prevent the melt from overflowing from the flask.
Comparative example 2
Synthesis of (2)
(1) To N 2 Reaction of atmosphere58.15g (0.35mol) of terephthalic acid, 39.37g (0.273mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol (cis content 45%), 26.25g (0.182mol) of 1, 4-cyclohexanedimethanol (cis content 26%) and 0.2039g of dibutyltin oxide are added into the reactor, and the mixture is reacted at 210 ℃ for 1h and at 220 ℃ for 3h to obtain an esterified product. During the reaction, a small amount of solid sublimated and remained in the subsequent pipeline, but the pipeline was not blocked.
(2) Polycondensing the esterification product at 260 deg.C under absolute pressure of less than or equal to 200Pa for 2h to obtain product with intrinsic viscosity of 0.62dL/g and phi cB 50.1 mol%, phi cis,cB 53.9 mol%, phi C 49.9 mol%, phi cis,C The copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-1, 4-cyclohexanedimethanol terephthalate), reported as 31.2 mole%
In the reaction process, a large amount of solid is pumped out of the reactor, a pipeline is seriously blocked (as shown in figure 1), the system is difficult to maintain at high vacuum degree, and the pipeline is dredged by heating the pipeline and timely removing the solid remained in the pipeline, so that the reaction can be continuously carried out at high vacuum degree. Furthermore, after 0.3h of reaction, the melt level in the reaction began to be unable to maintain a steady state, unstable evolution of gas, severe foaming and foaming resulted in high void volumes, and it was necessary to break the foam and bubble by stirring to prevent the melt from overflowing from the flask.
Comparative example 3 commercial copolyester having the designation EX401 was made up by nuclear magnetic analysis, phi cB 36.6 mol%, phi cis,cB 55.4 mol%, phi C 63.4 mol%, phi cis,C It was 29.6 mol%. The intrinsic viscosity was 0.66 dL/g.
Example 1
Synthesis of (2)
(1) To N 2 An atmospheric reactor was charged with 67.96g (0.35mol) of dimethyl terephthalate, 30.28g (0.21mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol (cis content 62%), 37.22g (0.315mol) of 3-methyl-1, 5-pentanediol, and oxydiphthalic acid0.2039g of butyltin, 10100.068g of main stabilizer and 6260.034 g of auxiliary stabilizer are added, and the mixture reacts for 3 hours at 220 ℃ to obtain an ester exchange product; during the reaction, no solids were observed in the line.
(2) Polycondensing the ester exchange product for 2.7h at 260 ℃ under the absolute pressure of less than or equal to 200Pa to obtain the product with the intrinsic viscosity of 0.75dL/g and phi cB 34.3 mol%, phi cis,cB The copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-3-methyl-1, 5-pentanediol terephthalate), at 63.8 mol%, is described as
During the reaction, a viscous clear liquid was observed to be drawn out of the reactor and finally into a collection bottle without blocking the line. The melt liquid level is kept stable all the time in the reaction process, and a small amount of bubbles are generated.
Example 2
Synthesis of (2)
(1) To N 2 An atmospheric reactor is added with 67.96g (0.35mol) of dimethyl terephthalate, 37.86g (0.2625mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol (with a cis content of 62%), 23.66g (0.2625mol) of 2-methyl-1, 3-propanediol and 0.2039g of dibutyltin oxide, 10100.068g of a main stabilizer and 6260.034 g of an auxiliary stabilizer are added, and the mixture reacts for 2.5h at 220 ℃ to obtain an ester exchange product; during the reaction, no solids were observed in the line.
(2) Polycondensing the ester exchange product at 260 deg.C under absolute pressure of less than or equal to 200Pa for 1.5h to obtain product with intrinsic viscosity of 0.70dL/g and phi cB 46.5 mol%, phi cis,cB Copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-2-methyl-1, 3-propanediol terephthalate) at 64.0 mole%, reported as
During the reaction, it was observed that a viscous transparent liquid was drawnOut of the reactor and finally into a collection bottle, without blocking the line (as shown in FIG. 2). The melt liquid level is kept stable all the time in the reaction process, and a small amount of bubbles are generated.
Example 3
Synthesis of (2)
(1) To N 2 58.15g (0.35mol) of terephthalic acid, 45.43g (0.315mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol (cis content is 60%), 21.87g (0.21mol) of 1, 5-pentanediol and 0.1744g of dibutyltin oxide are added into an atmosphere reactor, and the mixture is reacted at 210 ℃ for 1h, 220 ℃ for 1h and 230 ℃ for 5h to obtain an esterified product. During the reaction, no solids were observed in the line.
(2) Polycondensing the esterification product at 260 deg.C under absolute pressure of less than or equal to 200Pa for 3h to obtain product with intrinsic viscosity of 0.67dL/g and phi cB 54.6 mol%, phi cis,cB Copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-1, 5-pentanediol terephthalate) at 62.8 mol%, reported
During the reaction, a viscous clear liquid with a small amount of white solid was observed to be drawn out of the reactor and finally into a collection bottle without blocking the line. The melt liquid level is kept stable all the time in the reaction process, and a small amount of bubbles are generated.
Example 4
Synthesis of (2)
(1) To N 2 67.96g (0.35mol) of dimethyl terephthalate, 45.43g (cis content is 62%) (0.315mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol, 24.82g (0.21mol) of 3-methyl-1, 5-pentanediol and 0.2039g of dibutyltin oxide are added into an atmosphere reactor, and the mixture is reacted at 210 ℃ for 1h and at 220 ℃ for 2h to obtain a transesterification product; during the reaction, no solids were observed in the line.
(2) Polycondensing the ester exchange product for 2h at 260 ℃ under the absolute pressure of less than or equal to 200Pa to obtain the product with the characteristic viscosity number of 0.63dL/g、φ cB Is 54.7 mol%, phi cis,cB Copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-3-methyl-1, 5-pentanediol terephthalate), at 64.0 mol%, reported
During the reaction, a viscous clear liquid was observed to be drawn out of the reactor and finally into a collection bottle without blocking the line. The melt level is kept stable all the time in the reaction process, and a small amount of bubbles are generated.
Example 5
Synthesis of (2)
(1) To N 2 67.96g (0.35mol) of dimethyl terephthalate, 45.43g (0.315mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol (cis content is 62%), 18.93g (0.21mol) of 2-methyl-1, 3-propanediol and 0.2039g of dibutyltin oxide are added into an atmosphere reactor, 10100.068g of a main stabilizer and 6260.034 g of an auxiliary stabilizer are added, and the mixture reacts for 3.5 hours at 220 ℃ to obtain an ester exchange product; during the reaction, no solids were observed in the line.
(2) Polycondensing the ester exchange product for 1.5h at 260 ℃ under the absolute pressure of less than or equal to 200Pa to obtain the product with the intrinsic viscosity of 0.60dL/g and phi cB Is 54.9 mol%, phi cis,cB The copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-2-methyl-1, 3-propanediol terephthalate), reported as 64.3 mole percent
The properties are shown in Table 4. During the reaction, a viscous clear liquid was observed to be drawn out of the reactor and finally into a collection bottle without blocking the line. The melt liquid level is kept stable all the time in the reaction process, and a small amount of bubbles are generated.
Example 6
Synthesis of (2)
(1) To N 2 Adding p-phenylene bis into an atmosphere reactor58.15g (0.35mol) of formic acid, 53.00g (0.3675mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol (with a cis content of 60%), 16.40g (0.1575mol) of 1, 5-pentanediol and 0.1744g of dibutyltin oxide are reacted at the temperature of 210 ℃ for 1h, at the temperature of 220 ℃ for 1h and at the temperature of 230 ℃ for 5h to obtain an esterified product; during the reaction, no solids were observed in the line.
(2) Polycondensing the esterification product at 260 deg.C under absolute pressure of less than or equal to 200Pa for 3h to obtain product with intrinsic viscosity of 0.59dL/g and phi cB 65.2 mol%, phi cis,cB The copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-1, 5-pentanediol terephthalate), noted as 61.9 mol%
During the reaction, a viscous clear liquid with a small amount of white solid was observed to be drawn out of the reactor and finally into a collection bottle without blocking the line. The melt level is kept stable all the time in the reaction process, and a small amount of bubbles are generated.
Example 7
Synthesis of (2)
(1) To N 2 67.96g (0.35mol) of dimethyl terephthalate, 53.00g (0.3675mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol (cis content is 62%), 18.61g (0.1575mol) of 3-methyl-1, 5-pentanediol and 0.2039g of dibutyltin oxide are added into an atmosphere reactor and reacted for 3 hours at 220 ℃ to obtain an ester exchange product; during the reaction, no solids were observed in the line.
(2) Polycondensing the ester exchange product for 2.7h at 260 ℃ under the absolute pressure of less than or equal to 200Pa to obtain the product with the intrinsic viscosity of 0.53dL/g and phi cB Is 64.3 mol%, phi cis,cB The copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-3-methyl-1, 5-pentanediol terephthalate), recorded as 63.9 mol%
During the reaction, a viscous clear liquid was observed to be drawn out of the reactor and finally into the collection bottle without blocking the line. The melt level is kept stable all the time in the reaction process, and a small amount of bubbles are generated.
Example 8
Synthesis of (2)
(1) Adding 67.96g (0.35mol) of dimethyl terephthalate, 45.43g (0.315mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol (with the cis content of 60%), 21.87g (0.21mol) of 1, 5-pentanediol and 0.2039g of dibutyltin oxide into a reactor with an atmosphere of N2, and reacting at 220 ℃ for 2.2 hours to obtain an ester exchange product; during the reaction, no solids were observed in the line.
(2) Polycondensing the ester exchange product at 260 deg.C under absolute pressure of less than or equal to 200Pa for 1.7h to obtain product with intrinsic viscosity of 0.90dL/g and phi cB 52.6 mol%, phi cis,cB Copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-1, 5-pentanediol terephthalate) at 59.2 mol%, reported as
The properties are shown in Table 4. During the reaction, a viscous clear liquid with a small amount of solid was observed to be drawn out of the reactor and finally into a collection bottle without blocking the line. The melt liquid level is kept stable all the time in the reaction process, and a small amount of bubbles are generated.
Example 9
Synthesis of (2)
(1) 58.15g (0.35mol) of terephthalic acid, 53.00g (0.3675mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol (cis content is 60%), 16.40g (0.1575mol) of 1, 5-pentanediol and 0.58g of dibutyltin oxide are added into a reactor with an atmosphere of N2, and the mixture is reacted at 210 ℃ for 1h, 220 ℃ for 1h and 230 ℃ for 4h to obtain an esterified product; during the reaction, no solids were observed in the line.
(2) Polycondensing the esterification product for 1.5h at 260 ℃ under the absolute pressure of less than or equal to 200Pa to obtain the productThe viscosity number is 0.69dL/g, phi cB 65.7 mol%, phi cis,cB The copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-1, 5-pentanediol terephthalate), noted as 61.1 mol%
The properties are shown in Table 4. During the reaction, a viscous clear liquid with a small amount of white solid was observed to be drawn out of the reactor and finally into a collection bottle without blocking the line. The melt liquid level is kept stable all the time in the reaction process, and a small amount of bubbles are generated.
Example 10
Synthesis of (2)
(1) Adding 58.15g (0.35mol) of terephthalic acid, 53.00g (0.3675mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol (with the cis content of 60%), 16.40g (0.1575mol) of 1, 5-pentanediol and 0.58g of dibutyltin oxide into a reactor with an atmosphere of N2, reacting at 210 ℃ for 1h, at 220 ℃ for 1h and at 230 ℃ for 4.5h to obtain an esterified product; during the reaction, no solids were observed in the line.
(2) Polycondensing the esterification product at 260 deg.C under absolute pressure of less than or equal to 200Pa for 2h to obtain product with intrinsic viscosity of 0.68dL/g and phi cB 64.5 mol%, phi cis,cB 61.5 mol% of copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-1, 5-pentanediol terephthalate), described as
The properties are shown in Table 4. During the reaction, a viscous clear liquid with a small amount of white solid was observed to be drawn out of the reactor and finally into a collection bottle without blocking the line. The melt level is kept stable all the time in the reaction process, and a small amount of bubbles are generated.
Example 11
Synthesis of (2)
(1) 58.15g (0.35mol) of terephthalic acid, 60.57g (0.42mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol (with a cis content of 60 percent), 10.94g (0.105mol) of 1, 5-pentanediol and 0.58g of dibutyltin oxide are added into a reactor with an atmosphere of N2, and the mixture is reacted at 210 ℃ for 1h, 220 ℃ for 1h and 230 ℃ for 5.3h to obtain an esterified product; during the reaction, no solids were observed in the line.
(2) Polycondensing the esterification product at 260 deg.C under absolute pressure of less than or equal to 200Pa for 2h to obtain product with intrinsic viscosity of 0.59dL/g and phi cB 75.6 mol%, phi cis,cB Copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-1, 5-pentanediol terephthalate) at 62.0 mol%, reported as
The properties are shown in Table 4. During the reaction, a viscous clear liquid with a small amount of white solid was observed to be drawn out of the reactor and finally into a collection bottle without blocking the line. The melt level is kept stable all the time in the reaction process, and a small amount of bubbles are generated.
Example 12
Synthesis of (2)
(1) Feeding 67.96g (0.35mol) of dimethyl terephthalate, 37.86g (0.26mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol (with a cis content of 62%), 31.02g (0.26mol) of 3-methyl-1, 5-pentanediol, 0.10g of TBT and 0.10g of dibutyltin oxide into a reactor with an N2 atmosphere, reacting at 210 ℃ for 1h, at 220 ℃ for 1.5h and at 230 ℃ for 0.5h to obtain an ester exchange product; during the reaction, no solids were observed in the line.
(2) Adding TBT 0.10g, polycondensing the ester exchange product at 260 deg.C under absolute pressure of less than or equal to 200Pa for 2 hr to obtain product with intrinsic viscosity of 0.69dL/g and phi cB 43.0 mol%, phi cis,cB The copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-3-methyl-1, 5-pentanediol terephthalate), at 63.4 mol%, is described
The properties are shown in Table 4. During the reaction, it was observed that the viscous transparent liquid was drawn out of the reactor,eventually into the collection bottle, unblocking the line. The melt level is kept stable all the time in the reaction process, and a small amount of bubbles are generated.
Example 13
Synthesis of (2)
(1) Adding 67.96g (0.35mol) of dimethyl terephthalate, 45.43g (0.315mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol (with the cis content of 62%), 24.82g (0.21mol) of 3-methyl-1, 5-pentanediol, 0.10g of TBT and 0.10g of dibutyltin oxide into a reactor with an atmosphere of N2, and reacting at 210 ℃ for 1h and 220 ℃ for 2h to obtain an ester exchange product; during the reaction, no solids were observed in the line.
(2) Adding 0.10g of TBT, polycondensing the ester exchange product for 2h at 260 ℃ under the absolute pressure of less than or equal to 200Pa to obtain the product with the intrinsic viscosity of 0.63dL/g and phi cB 54.7 mol%, phi cis,cB Copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-3-methyl-1, 5-pentanediol terephthalate) at 64.0 mol%, reported as
The properties are shown in Table 4. During the reaction, a viscous clear liquid was observed to be drawn out of the reactor and finally into a collection bottle without blocking the line. The melt level is kept stable all the time in the reaction process, and a small amount of bubbles are generated.
Example 14
Synthesis of (2)
(1) 58.15g (0.35mol) of terephthalic acid, 45.42g (0.315mol) of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol (cis content is 62%), 10.94g (0.105mol) of 1, 5-pentanediol, 6.517g (0.105mol) of ethylene glycol and 0.1745g of dibutyltin oxide are added into a reactor with an atmosphere of N2, and the mixture is reacted at 210 ℃ for 1h, 220 ℃ for 1h and 230 ℃ for 4h to obtain an esterified product; during the reaction, no solids were observed in the line.
(2) Polycondensing the esterification product for 1.3h at 270 ℃ under the absolute pressure of less than or equal to 200Pa to obtain the productThe viscosity number is 0.62dL/g, phi cB 63.6 mol%, phi cis,cB 62.0 mol%, phi Pe 27.5 mol%, phi E Copolyester poly (2,2, 4, 4-tetramethyl-1, 3-cyclobutanediol-co-1, 5-pentanediol-co-ethylene terephthalate) at 8.9 mol%, reported
The properties are shown in Table 4. During the reaction, a viscous clear liquid was observed to be drawn out of the reactor and finally into the collection bottle without blocking the line. The melt liquid level is kept stable all the time in the reaction process, and a small amount of bubbles are generated.
Performance analysis
Firstly, about the blockage situation of the pipeline and the equipment
In the synthesis of PCcBT of comparative examples 1-2, CBDO and CHDM monomers are solid at room temperature, volatile and easy to sublimate, which easily causes the pipeline to be blocked in the polycondensation stage, especially serious for the synthesis of copolyester with high CBDO content, and even causes the pipeline to be blocked in the esterification/transesterification stage, thus causing the reaction to be difficult to continue, and the results of comparative example 1 are shown in fig. 1. Increasing the line temperature avoids the above problems, but increases process costs and energy consumption.
In the synthesis of the copolyesters of the present invention, as in examples 1-14, the fractions obtained during the synthesis were free or very low in visible solids, viscous but liquid with good flow properties, and the lines were not blocked, especially when the first diol was 3-methyl-1, 5-pentanediol or 2-methyl-1, 3-propanediol, the results of example 2 being shown in fig. 2. This is associated with the first diol being liquid at ambient temperature and the CBDO having good solubility in the first diol. The results show that the method has no pipeline blockage in the synthesis process, higher safety and lower operation energy consumption.
Two, composition deviation and cis-trans ratio deviation of copolymer
CBDO is a key monomer of the copolyester with high transparency and high heat resistance and is also key to controlling the cost of the copolyester, so that the CBDO monomer which is input is hoped to be completely or possibly input in industryIs introduced into the copolyester chain structure to reduce the loss and recovery load of the CBDO monomer. However, in practice, the content (. phi.) of CBDO residues in the copolyester is lost due to side reactions of CBDO (especially, trans-CBDO is more susceptible to side reactions), volatilization, sublimation, etc cB ) Often significantly lower than the CBDO level of the diol monomer
Cis cB content (. phi.) of the copolyester cis,cB ) Is obviously higher than the cis-CBDO content in the monomer
There is a deviation between them.
The compositional deviation, the relative compositional deviation, the cis deviation, and the cis relative deviation of the copolyesters obtained in comparative examples 1-2 and examples 1-14 are shown in Table 2. Wherein
The results show that the composition deviation, relative composition deviation, cis deviation and cis relative deviation of the copolyesters obtained in examples 1-14 are significantly lower than those of comparative examples 1-2, indicating that the present invention has a significant advantage in avoiding the side reaction and loss of CBDO so as to introduce the input CBDO into the copolyester as much as possible.
TABLE 2 comparison of monomer and copolyester compositions, cis content
Third, regarding polycondensation temperature and intrinsic viscosity
Because CBDO has a cyclic large steric hindrance structure and the hydroxyl group is connected with a secondary carbon, the reaction activity of CBDO with acid or ester is obviously lower than that of the first dihydric alcohol. With increasing CBDO content, the molecular weight of the copolyester is more difficult to increase. In order to obtain high intrinsic viscosity, the prior art often adopts high (more than or equal to 280 ℃) polycondensation reaction temperature. Although the PCcBT copolyester with higher intrinsic viscosity can be prepared under the reaction conditions of the comparative example of the invention, the pipeline is seriously blocked. The preparation method of the copolyester can prepare the copolyester with high intrinsic viscosity at a lower polycondensation reaction temperature (about 260 ℃), the intrinsic viscosity is at least 0.53dL/g, most of the intrinsic viscosity is more than or equal to 0.60dL/g and can reach as high as 0.90dL/g, and the intrinsic viscosity can still reach 0.59dL/g even when the cB content is 76% (example 11). The above results show that the present invention can successfully synthesize high molecular weight CBDO-based copolyesters at polycondensation temperatures below 280 ℃.
Thermal stability of copolyester melt
The PCcBT copolyester of comparative example 1 had a very unstable melt level during vacuum polycondensation, the level surges dramatically, requiring faster stirring to prevent melt overflow from the flask. The polyesters synthesized in examples 1 to 14, however, were able to maintain a stable melt level during the vacuum polycondensation, similar to the phenomenon that the excess diol was slowly removed during the conventional polyester synthesis. The results demonstrate that the CBDO-based copolyesters provided by the present invention have superior melt stability.
To further evaluate the melt stability of the copolyesters, 1 gram of each of the copolyester samples synthesized in comparative example 1, and example 2 was re-introduced into a 50mL flask in N 2 Heating to 240 deg.C under atmosphere without stirring, maintaining at 240 deg.C for 5 hr, naturally cooling to room temperature, and observing the final state, as shown in FIG. 3. It can be seen that the copolyester of comparative example 1 (fig. 3 (a)) produced a large amount of intensive foaming, and the copolyesters of examples 1 and 2 (fig. 3 (b) and (c)) produced significantly less bubbles. The copolyesters of comparative examples 1-2 were also found to expand very significantly when injection molded using a MiniJet microinjection molding machine, and the copolyesters of examples 1-14, although still showing some expansion, were much less extensive, especially the copolyesters synthesized with 2-methyl-1, 3-propanediol as the first diol. The above results show that the copolyesters of the present invention haveThe improved melt stability is more favorable for the smooth polymerization and processing.
V, regarding thermal stability and mechanical property
The Tg and mechanical properties of the copolyester were measured, and the results are shown in tables 3 and 4. It can be seen that the Tg of the copolyesters of the invention can be adjusted over a wide range (49-136 ℃), and that by increasing the content of cB units, high Tg copolyesters, especially copolyesters with 2-methyl-1, 3-propanediol as the first diol monomer, can be produced with Tg as high as 136 ℃, although at the same cB content the glass transition temperature is lower than PCcBT. The copolyesters of the invention have higher Young's modulus, tensile strength and ductility when their glass transition temperature is similar to or higher (>110 ℃ C.) than comparative examples 1 and EX401, as in examples 5, 10, 14 and 11. When its Tg is lower than that of comparative example 1 and EX401, it also has higher rigidity, strength and ductility as in example 12.
TABLE 3 glass transition temperature of copolyesters
TABLE 4 mechanical Properties of copolyesters in the examples and comparative examples
Sixthly, regarding color and luster and transparency
The color and transparency of the sheets obtained by compression molding the copolyesters of comparative example 1 and example 5 were observed, and the results are shown in FIG. 4, in which (a) is comparative example 1 and (b) is example 5. It can be seen from the figure that the copolyester prepared in example 5 is nearly colorless and transparent, and the inventors have also made copolyesters of other examples, which have transparency similar to that of example 5, good transparency, and color and transparency comparable to PCcBT.
Claims (9)
1. A high-transparency high-heat-resistance copolyester resin is characterized by comprising the following components:
(1) a dibasic acid component comprising, in a total amount of 100 mol%:
(a)80 to 100 mole% of terephthalic acid residues; and
(b)0 to 20 mol% of aromatic dibasic acid residues;
and
(2) a glycol component comprising, based on 100 mol% of the total:
(a)34-80 mol% CBDO residues; and
(b)20-66 mol% of a first diol residue; and
(c)0 to 30 mole% of a second glycol residue;
the aromatic dibasic acid residue comprises at least one of isophthalic acid residue, phthalic acid residue, diphenic acid residue, naphthalenedicarboxylic acid residue, furandicarboxylic acid residue and thiophenedicarboxylic acid residue;
the first diol residue is a 3-methyl-1, 5-pentanediol residue or a 2-methyl-1, 3-propanediol residue;
the second diol residue comprises at least one of aliphatic diol residue with the main chain carbon atom number less than or equal to 4 or alicyclic or heterocyclic diol residue with the carbon atom number less than or equal to 12.
2. The high-transparency high-heat-resistance copolyester resin according to claim 1, wherein the aliphatic diol residue having a carbon number of the main chain of 4 or less comprises at least one of ethylene glycol residue, 1, 3-propylene glycol residue, 1, 4-butylene glycol residue, 2, 3-butylene glycol residue and 1, 2-propylene glycol residue;
the alicyclic or heterocyclic diol residue with the carbon number less than or equal to 12 comprises at least one of 1, 4-cyclohexanedimethanol residue and cyclohexanediol residue.
3. The high-transparency high-heat-resistance copolyester resin according to claim 1, wherein the intrinsic viscosity of the copolyester resin is 0.53-0.90 dL/g.
4. The highly transparent and highly heat-resistant copolyester resin according to claim 1, wherein the glass transition temperature of the copolyester resin is 60 to 150 ℃.
5. The method for preparing a highly transparent and highly heat resistant copolyester resin according to any one of claims 1 to 4, comprising the steps of:
(1) carrying out esterification or ester exchange reaction on a mixture containing a dibasic acid component and a dibasic alcohol component at the temperature of 200-250 ℃ to obtain an intermediate product;
(2) polycondensing the intermediate product at the pressure of 10-200Pa and the temperature of 250-270 ℃ to obtain the copolyester resin;
the mixture comprises the following components:
(1) a dibasic acid component comprising, in a total amount of 100 mol%:
(a)80 to 100 mole% of terephthalic acid or its dimethyl ester; and
(b)0 to 20 mol% of an aromatic dibasic acid or its dimethyl ester;
and
(2) a glycol component comprising, based on 100 mol% of the total:
(a)40-80 mol% CBDO; and
(b)20-60 mol% of a first dihydric alcohol; and
(c)0 to 30 mol% of a second glycol;
the molar ratio of the dibasic acid component to the dibasic alcohol component is 1:1-1: 3;
the aromatic dibasic acid or the dimethyl ester thereof comprises at least one of isophthalic acid or the dimethyl ester thereof, phthalic acid or the dimethyl ester thereof, biphenyl dicarboxylic acid or the dimethyl ester thereof, naphthalene dicarboxylic acid or the dimethyl ester thereof, furan dicarboxylic acid or the dimethyl ester thereof, and thiophene dicarboxylic acid or the dimethyl ester thereof;
the first dihydric alcohol is 3-methyl-1, 5-pentanediol or 2-methyl-1, 3-propanediol;
the second dihydric alcohol comprises at least one of aliphatic dihydric alcohol with the main chain carbon atom number less than or equal to 4 or alicyclic or heterocyclic dihydric alcohol with the carbon atom number less than or equal to 12.
6. The method for preparing a highly transparent and heat resistant copolyester resin according to claim 5, wherein the aliphatic diol having a carbon number of the main chain of 4 or less comprises at least one of ethylene glycol, 1, 3-propanediol, 1, 2-propanediol, 1, 4-butanediol, 2, 3-butanediol, 1, 2-pentanediol, and 1, 4-pentanediol;
the alicyclic or heterocyclic diol with the carbon number less than or equal to 12 comprises at least one of 1, 4-cyclohexanedimethanol and cyclohexanediol.
7. The method for preparing a highly transparent and highly heat resistant copolyester resin according to claim 5, wherein in the copolyester resin,
the difference between the molar percentage of the CBDO residue in the diol residue and the molar percentage of the CBDO monomer in the diol monomer is less than or equal to 8 mol%;
the difference between the proportion of the cis-CBDO residue in the CBDO residue and the proportion of the cis-CBDO monomer in the CBDO monomer is less than or equal to 8 percent.
8. The method for preparing high transparent high heat resistant copolyester resin according to claim 5, wherein the mixture further comprises catalyst, heat stabilizer, light stabilizer;
the dosage of the catalyst is less than 1 wt% of the mass of the dibasic acid component;
the using amount of the heat stabilizer is 0.1-1 wt% of the weight of the dibasic acid component;
the dosage of the light stabilizer is less than 1 wt% of the mass of the dibasic acid component.
9. The method for preparing a highly transparent and highly heat resistant copolyester resin according to claim 8, wherein the catalyst comprises tin-based catalyst; or comprises tin catalyst and one or more of tetrabutyl titanate, isopropyl titanate, lithium acetate, potassium acetate, calcium acetate, magnesium acetate, barium acetate, zinc acetate, cobalt acetate, antimony acetate, lead acetate and manganese acetate;
the tin catalyst is selected from one or more of dibutyltin oxide, stannous octoate, stannous oxalate, dibutyltin diacetate and dibutyltin dilaurate;
the heat stabilizer is selected from heat stabilizer 1010, heat stabilizer 1500, heat stabilizer 1076, heat stabilizer 425, heat stabilizer 330, heat stabilizer 1178, heat stabilizer 501, heat stabilizer 618, heat stabilizer 626, heat stabilizer 168, TDD, trimethyl phosphite, triethyl phosphite, triisooctyl phosphite, triisodecyl phosphite, trilauryl phosphite, tris (tridecyl) phosphite, trioctadecyl phosphite, triphenyl phosphite, tri-p-tolyl phosphite, ditridecyl phosphite, tris (2, 4-di-tert-butyl) phosphite, pentaerythritol bis (2, 4-tert-butylphenyl) diphosphite, pentaerythritol tetrapentaphenyl tridecyl phosphite, pentaerythritol ditridecyl phosphite, pentaerythritol diisodecyl diphosphite, pentaerythritol dioctadecyl phosphite, phosphoric acid, sulfuric acid, phosphoric acid, one or more of phosphorous acid, polyphosphoric acid and triethyl phosphonoacetate;
the light stabilizer is selected from one or more of light stabilizer 791, light stabilizer 700, light stabilizer 783, light stabilizer 119, light stabilizer 770, light stabilizer 622, light stabilizer 944, light stabilizer 1164, 2,2,6, 6-tetramethyl-4-piperidine stearate, bis (2,2,6, 6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6, 6-pentamethyl-4-piperidyl) sebacate, 2-hydroxy-4-n-octoxybenzophenone and (3, 5-di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole.
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