CN109553776B

CN109553776B - Polyester block copolymer and preparation method and application thereof

Info

Publication number: CN109553776B
Application number: CN201710889156.3A
Authority: CN
Inventors: 崔晓文; 汪永斌; 庞小琳; 姚君; 黄华; 胥保礼; 戴伍国
Original assignee: Nantong Xingchen Synthetic Materials Co Ltd
Current assignee: Nantong Xingchen Synthetic Materials Co Ltd
Priority date: 2017-09-27
Filing date: 2017-09-27
Publication date: 2021-09-03
Anticipated expiration: 2037-09-27
Also published as: WO2019062428A1; CN109553776A

Abstract

The invention discloses a polyester block copolymer which is characterized in that the structure is shown as the following formula (I); the invention also discloses a preparation method of the polyester block copolymer. According to the invention, the silicon-containing unit is polymerized into the polyester molecular chain by a copolymerization method, and the obtained copolymer has excellent low temperature resistance and lower surface tension, so that the characteristic of low temperature resistance of the polyester resin is improved, and the application space of the polyester resin in the fields of fibers, films, blow molding and engineering plastics is expanded. A. the_n‑B_t (I)。

Description

Polyester block copolymer and preparation method and application thereof

Technical Field

The invention belongs to the technical field of polymer synthetic materials, and particularly relates to a polyester block copolymer with cold resistance and hydrophobicity and a preparation method thereof.

Background

With the development of society and the progress of science and technology, the demand of human beings on materials is increasingly expanded, and the production and application of polymer synthetic materials are rapidly developed. Among them, the applications of engineering plastics in various fields are also expanding year by year. Polyester material, one of five engineering plastics, mainly refers to PBT, the Chinese name is polybutylene terephthalate, and is a semi-crystalline thermoplastic resin, and the polyester material is mainly applied to the fields of electronic and electric appliances, automobiles, illumination, machinery, spinning, communication, films, instruments and meters and the like due to the advantages of high modulus, high strength, high elasticity, heat resistance and the like. PET, the Chinese name of polyethylene terephthalate, because of its better mechanical properties, high temperature resistance and scratch resistance, is widely used in the fields of spinning, film, blow molding, etc. What we would normally say is polyester which is spun using PET material. PTT, the Chinese name of polytrimethylene terephthalate, as a new star of a polyester family, has excellent rebound resilience and dyeing property, and provides a new choice for the spinning industry. PCT, the chinese name of polycyclohexanedimethylene terephthalate and PEN, and the chinese name of polyethylene naphthalate are used in the fields of machinery, electronics, automobiles, and the like in high temperature environments due to their high temperature resistance and mechanical properties.

The polyester materials mentioned above are all excellent in mechanical properties, but are relatively brittle and have insufficient toughness, and especially at low temperatures, they have almost no toughness, and are in the case of breaking at once. This disadvantage limits the use of polyesters. China is vast in Liaoning, the temperature difference of different regions in south and north is extremely large, particularly in winter, the sea-south island still has bright sun, high illumination and warm wind habit, and the temperature exceeds 20 ℃; black Longjiang is another scene, which is cool in cold weather, and the lowest temperature can be as low as-40 ℃. As the clothes for keeping out cold and keeping warm, the polyester fibers, the PBT fibers and the PTT fibers cannot play a role in the environment, and the clothes made of the polyester fibers, the PBT fibers and the PTT fibers are expected to be broken once being hit, so that the application of the PET, the PBT and the PTT is greatly limited. For another example, PET and PBT films, especially biaxially oriented films, tend to suffer from embrittlement and cracking in the-40 ℃ environment, which can present a safety hazard to the equipment and devices in which they are used. In the field of household appliances, PBT injection-molded grade materials are also limited in application due to their brittleness, since the freezer compartment operates in an environment of-20 ℃ throughout the year. Therefore, if a common substance can be found, the toughness, especially the low-temperature toughness of the materials can be improved, the application fields can be obviously widened, and the method has very important practical significance.

In the second aspect, the polyester is a high molecular polymer obtained by condensation of a diacid and a diol to remove water molecules, and the presence of an ester bond imparts a certain polarity to the polyester material. The higher the polarity, the more moisture-absorbing and adsorbing other small molecules or particulate impurities, and the lower the polarity, the less moisture-absorbing and adsorbing other small molecules or particulate impurities. At present, PET fibers, PBT fibers and PTT fibers are widely used for various human clothes, and the fluffy fiber structure can better keep warm, so that the clothes can be more wonderful and are more comfortable to wear. In east China, the rain and the shade are continuous in winter every year, clothes worn by people are not as warm as before due to the moisture absorption of polyester fibers, cotton quilts are heavy and not warm, and the clothes are clear in the day and are taken out of the room to be dried in the sun. Films made of PET and PBT resins are generally rolled up for ease of shipping, but the rolled up films are difficult to unroll due to the polarity of the PET and PBT molecules. In recent years, as a material of an automobile lamp decorative frame, a spraying-free primer-free PBT material is developed quickly, but in order to ensure higher flatness and mirror surface requirements, the surface smoothness of a mould is very high, and the PBT material also has the defect of difficult demoulding. The higher polarity brings about the defect of the application of the polyester material, and how to reduce the polarity of the polyester and improve the convenience of the application and the comfort of the use of the polyester material also has very important practical significance.

How to simultaneously improve the low temperature resistance of polyester materials and reduce the molecular polarity, and expand the application field of the polyester materials is not published at present. Patent CN100551053C proposes to solve the adhesion of mylar, and to satisfy the anti-adhesion requirement in the electronic application field by coating a silicone anti-adhesive liquid on one side of the mylar, and by stably and uniformly coating the anti-adhesive liquid on the mylar. Patent CN105538853A discloses a co-extrusion method, which adds siloxane additive to the upper or lower surface layer material to obtain a low polarity film. Patent CN103042780B provides a co-extrusion method, in which polyester and thermoplastic elastomer are co-extruded to form a composite film, so as to achieve the effect of low temperature resistance. Patent CN104136534A discloses a low temperature resistant poly (alkylene carbonate) resin composition, which is prepared by introducing epoxy compound for copolymerization to prepare low temperature resistant resin material, but the introduction of epoxy compound is not effective to reduce the polarity of resin, which is not mentioned in the patent. Patent CN102382307A discloses a method for preparing dihydroxyaryl siloxane, which is used to improve the compatibility of polycarbonate with its copolymerized polymer, mainly by reacting with phosgene in solution to form polycarbonate copolymer, but is not used in the polyester field, and fiber and film field. The patent US5132392A shows better hydrophilic properties of the formed copolyester by introducing polysilanes containing polyether segments at the ends, but the compound does not provide improved low temperature resistance and hydrophobic properties of the material. The improvement of the resistance to hydrolysis of the material is enhanced by the copolyester obtained by introducing a specific polysiloxane, whose end groups are alkyl epoxy groups, into the U.S. Pat. No. 4, 4927895A, which does not mention the improvement of the resistance to low temperatures and the hydrophobicity, by reacting the epoxy with the terminal carboxyl or hydroxyl groups of the polyester. U.S. Pat. No. 4, 4894427A provides a polysilane-containing polyester copolymer obtained mainly by copolymerizing polysilane having a hydroxyalkyl group at the end with a dicarboxylic acid, and the hydrolysis resistance of the resulting copolymer is improved, but the low-temperature resistance and the hydrophobic property are not mentioned.

In engineering plastic modification applications, silicone resins are often used to enhance the mold release properties of the final modified material, since the added silicones are small molecule materials, and after the modification is extruded by blending, silicone molecules easily migrate to the surface of the material, thereby reducing the surface tension of the material and making it easier to injection mold. However, the disadvantage is that the amount of silicone resin added cannot be too high, otherwise the small added silicone molecules migrate to the surface of the part, forming oil spots and defects. It has also been proposed to add other low surface energy additives, for example, by means of blending and extrusion, to extrude and granulate silicone rubber and nylon resin to achieve the purpose of improving the low temperature impact resistance of the resin, but because the two resins have too great difference to achieve uniform mixing, the silicone rubber is not uniformly dispersed in the nylon resin, the performance fluctuates, and it is often difficult to control in the production process, and for the application field of products or spinning films requiring more precision, stable production cannot be achieved, and the application thereof is limited. If the micromolecular organic silicon or oligomer and polyester can be copolymerized in a polymerization mode, the organic silicon can be uniformly dispersed in the polyester resin, the novel material has the higher mechanical property of the polyester resin and the low-temperature resistance and hydrophobicity of the silicon resin, and the organic silicon molecules are dispersed in the resin in a molecular level, so that the material has stable performance, small volatility and more excellent performance, and the application field of the material is greatly expanded. The aforementioned patents mention copolymers containing polysilanes, but do not address the low temperature resistance and hydrophobic properties of the materials. Meanwhile, the patent CN102382307A only studies the reaction with phosgene to form polycarbonate copolymer; the patent US4927895A adopts polysilane with epoxy group at the tail end to react with polyester tail end to obtain copolymer, and the material has harsh requirements on environment and can not absorb moisture, thus seriously affecting the use of the material; the patents US5132392A and US4894427A mentioned above use hydroxyl-terminated polysilanes for copolymerization to obtain new polymers with improved hydrophilic and hydrolysis resistance, but because of the one-step polymerization adopted, the reaction rate difference between polysilanes and diols results in the uneven distribution of polysilanes in the copolymer, and other properties of the material are affected, so there is no mention of the low temperature resistance and hydrophobic properties of the obtained polymers. As described above, in the published literature, no published report has been found that can solve the above-mentioned low temperature resistance and hydrophobic property of the polyester material.

Disclosure of Invention

The present invention has been made to overcome the above-mentioned disadvantages of the prior art, and an object of the present invention is to provide a cold-resistant and hydrophobic polyester block copolymer by copolymerization. The novel polyester block polymer prepared by the invention endows a novel material with lower surface tension and higher impact strength at low temperature, and provides possibility for application expansion of the material.

The invention introduces polysilane molecules into the molecular structure of polyester, and obtains a polyester block copolymer by a copolymerization method, and the prepared polyester block copolyester has a structure shown in the following general formula (1):

A_n-B_t (I)

in formula (I):

the A block is polyester obtained by the reaction of dibasic acid and dihydric alcohol; wherein the dibasic acid is selected from one or more of aromatic dicarboxylic acid and aliphatic dicarboxylic acid; the dihydric alcohol is selected from one or more of aliphatic dihydric alcohol and alicyclic dihydric alcohol;

the B block structure is shown as the formula (II):

in the formula (II): r₄、R₅Each independently selected from methyl, ethyl, propyl, phenyl, alpha-methylphenyl or p-methylphenyl; r₆Is represented by (CH)₂)₂、(CH₂)₃、(CH₂)₄、(CH₂)₆、

One or more of the above; s is an integer greater than 1;

in the block copolymer, n is an integer greater than 1, and t is an integer greater than 1.

The polyester block copolymer meets the condition that the sum of the percentage of the A block in the total mass of the copolymer and the percentage of the B block in the total mass of the copolymer is 100 percent; preferably, the mass of the B block is 0.1% to 50%, more preferably 0.5% to 30%, still more preferably 3% to 20%, and still more preferably 10% to 15% of the total mass of the copolymer.

In the A block of the polyester block copolymer, the aromatic dicarboxylic acid is selected from one or more of terephthalic acid, isophthalic acid and naphthalene diacid; the aliphatic dicarboxylic acid is selected from one or more of succinic acid, adipic acid and suberic acid; the alicyclic diol is one or more selected from ethylene glycol, propylene glycol, butanediol, hexanediol and 1, 4-cyclohexanedimethanol.

In the B block of the polyester block copolymer, s is more than or equal to 1 and less than or equal to 100; preferably, 1. ltoreq. s.ltoreq.50; more preferably, 1. ltoreq. s.ltoreq.30; further preferably, 1. ltoreq. s.ltoreq.50. The R is₄、R₅Are the same or different, preferably the same, more preferably R₄And R₅Are all methyl.

The intrinsic viscosity of the polyester block copolymer provided by the invention is 0.6-2.0 dL/g, and preferably 0.79-1.33 dL/g. Unless otherwise specified, the intrinsic viscosities of the invention are measured according to ASTM D445.

As a preferred embodiment of the present invention, the polyester block copolymer is selected from one or more of the following structures:

the polyester block copolymer provided by the invention has excellent low-temperature resistance, good low-temperature impact property and small apparent tension, and can be used in the application fields of cold resistance and hydrophobicity, such as the fields of fibers, films, bottles and cans, engineering plastics and the like.

The invention also provides a preparation method of the polyester block copolymer, which comprises esterification reaction, pre-polycondensation reaction and polycondensation reaction; further, if necessary, a solid-phase thickening reaction may be performed.

Specifically, the method comprises the following steps:

(1) putting dicarboxylic acid and dihydric alcohol into a reaction kettle for esterification reaction;

the dicarboxylic acid in the step is selected from one or more of aromatic dicarboxylic acid and aliphatic dicarboxylic acid; the dihydric alcohol in the step is selected from one or more of aliphatic dihydric alcohol and alicyclic dihydric alcohol;

(2) placing alpha, omega-dicarboxy polysilane shown in formula (III) and dihydric alcohol in a reaction kettle for esterification reaction;

in the formula (III), R₄、R₅Each independently selected from methyl, ethyl, propyl, phenyl, alpha-methylphenyl or p-methylphenyl; s is an integer greater than 1;

the dihydric alcohol in the step is selected from one or more of aliphatic dihydric alcohol and alicyclic dihydric alcohol;

(3) placing the product obtained in the step (1) and the product obtained in the step (2) into a reaction kettle, and carrying out a pre-polycondensation reaction to generate a pre-polycondensation product;

(4) and (4) placing the pre-polycondensation product obtained in the step (3) into a reaction kettle, and carrying out polycondensation reaction to obtain the polyester block copolymer.

In order to increase the viscosity of the polyester block copolymer, the method of the present invention may further comprise subjecting the product obtained in step (4) to solid-phase tackifying reaction. The solid phase tackifying reaction can be carried out in a vacuum state (3-100Pa) or in an inert gas-shielded state (the flow rate of the inert gas is 0.5-5L/[ min KG tackifying particles ]). Preferably, the temperature of the solid phase tackifying reaction is 100-260 ℃, and the general reaction time is 4-36 hours. The intrinsic viscosity of the resulting polyester block copolymer is set to 0.8 to 2.0dL/g, preferably 0.79 to 1.33dL/g, by a solid-phase thickening reaction. The specific reaction conditions can be determined according to actual needs.

In the step (1), the dicarboxylic acid may be one or a mixture of several selected from phthalic acid (PTA), isophthalic acid (PIA), 2, 6-Naphthalene Dicarboxylic Acid (NDA), 1, 4-Succinic Acid (SA), adipic acid, and suberic acid; the dihydric alcohol is one or a mixture of more of ethylene glycol, 1, 3-propylene glycol, 1, 4-butanediol, 1, 6-hexanediol and 1, 4-Cyclohexanedimethanol (CHDM).

The present invention further prefers the combination of the dicarboxylic acid and the diol in step (1), and specifically: the dicarboxylic acid is terephthalic acid, and the dihydric alcohol is ethylene glycol; or the dicarboxylic acid is terephthalic acid, and the dihydric alcohol is 1, 3-propanediol; or the dicarboxylic acid is terephthalic acid, and the dihydric alcohol is 1, 4-butanediol; or the dicarboxylic acid is terephthalic acid and the diol is 1, 4-Cyclohexanedimethanol (CHDM); or the dicarboxylic acid is 2, 6-Naphthalene Dicarboxylic Acid (NDA) and the diol is ethylene glycol; or the dicarboxylic acid is 2, 6-naphthalenedicarboxylic acid, and the diol is 1, 4-butanediol; or the dicarboxylic acid is 1, 4-Succinic Acid (SA), and the dihydric alcohol is 1, 4-butanediol; or the dicarboxylic acid is terephthalic acid, and the dihydric alcohol is ethylene glycol and 1, 4-cyclohexanedimethanol.

In the step (2), the compound represented by the formula (III) may be selected from α, ω -dicarboxyethyl polydimethylsiloxane, α, ω -dicarboxyethyl polydiethylsiloxane, α, ω -dicarboxyethyl polymethylphenylsiloxane, α, ω -dicarboxyethyl polydiphenylsiloxane, and the like. The dihydric alcohol is one or a mixture of more of ethylene glycol, 1, 3-propylene glycol, 1, 4-butanediol, 1, 6-hexanediol and 1, 4-Cyclohexanedimethanol (CHDM).

The invention optimizes the consumption of raw materials in each step, thereby obtaining the polyester block copolymer with excellent performance. Specifically, in the step (1), the molar ratio of the dicarboxylic acid to the diol is 1:1 to 1: 1.5. In the step (2), the molar ratio of the compound shown in the formula (III) to the dihydric alcohol is 1: 1.2-1: 1.5. In the step (3), the proportion of the product obtained in the step (2) to the sum of the product obtained in the steps (1) and (2) is 0.1-50%, preferably 0.5-30%, more preferably 3-20%, and even more preferably 10-15%.

In the esterification reaction in the step (1) and the step (2), a catalyst is preferably used for catalysis. The catalyst can be selected from one or a compound of more of germanium oxide, manganese acetate, zinc acetate, tetrabutyl titanate, antimony trioxide, ethylene glycol antimony and ethylene glycol titanium. The mass of the catalyst is preferably 0.01-0.1% of the total mass of the reaction raw materials.

In the present invention, it is preferable to use a mixed system of the above catalyst and glycol in the esterification reaction, and the preparation method of the catalyst mixed system comprises: and (3) placing the dihydric alcohol and the catalyst into a reaction kettle according to the proportion, heating and boiling for 2-4 hours under a vacuum state, wherein the vacuum degree is 20-30KPa, the temperature is 170-200 ℃, and cooling. Wherein the molar ratio of the dihydric alcohol to the catalyst is 1: 3-1: 6.

The esterification reaction is carried out according to conventional conditions. As a preferred embodiment: the esterification reaction conditions in step (1) are preferably: the temperature is 160-245 ℃, and the vacuum degree is 40-45 KPa; the esterification reaction conditions in the step (2) are as follows: the temperature is 160-245 ℃, and the vacuum degree is 40-45 KPa.

In order to improve the polymerization effect and the comprehensive performance of the obtained product, the invention adopts a scheme of carrying out pre-polycondensation reaction firstly and then carrying out polycondensation reaction, and optimizes the reaction conditions of the two-step polycondensation.

Specifically, the method comprises the following steps: the pre-polycondensation reaction conditions in the step (3) are as follows: the temperature is 180-310 ℃, the vacuum degree is 1.5-2.5KPa, and the reaction time is 30-60min generally; the polycondensation reaction conditions in the step (4) are as follows: the temperature is 180-310 ℃, the vacuum degree is 100-200Pa, and the reaction time is 60-240 min.

The initial polycondensation process in the esterification reaction is continued in a pre-polycondensation kettle, the pre-polycondensation reaction generates a low molecular weight polyester copolymer, and the pre-polycondensation product enters a polycondensation reactor after passing through a pre-polycondensation discharge pump, a pre-polycondensation discharge filter and a pre-polycondensation discharge cooler. The polycondensation reaction produces a high molecular weight polyester block copolymer. The polycondensation product enters a granulator system through a polycondensation discharge pump, a polymer viscometer, a polycondensation discharge filter and a polycondensation discharge distribution valve. Cooling and pelletizing to obtain the high molecular weight polyester block copolymer product. The resulting polyester block copolymer has an intrinsic viscosity of 0.5 to 1.0 dL/g.

When the method further carries out solid-phase tackifying reaction, the temperature of the solid-phase tackifying reaction is 100-260 ℃.

As a preferable scheme of the invention, the method comprises the following specific steps:

s1: preparation of slurry

Placing dicarboxylic acid and dihydric alcohol into a container (a preparation tank), and uniformly stirring to obtain a mixed material S1; wherein the molar ratio of dicarboxylic acid to dihydric alcohol is 1: 1-1: 1.5;

placing the compound shown in the formula (III) and dihydric alcohol in a container (a preparation tank), and uniformly stirring to obtain a mixed material S2; wherein the molar ratio of the compound shown in the formula (III) to the dihydric alcohol is 1: 1.2-1: 1.5;

s2: catalyst formulation

Adding the dihydric alcohol and the catalyst into a container (a preparation tank) according to the molar ratio of 1: 3-1: 6, heating and boiling for 2-4 hours under a vacuum state, wherein the vacuum degree is 20-30KPa, the temperature is 170-200 ℃, and cooling; preparing a catalyst mixed system;

s3: esterification reaction

Placing the mixed material S1 into a reaction kettle (esterification kettle), and adding the catalyst mixed system prepared in the step S2 for esterification reaction until no water is generated; oligomer OM1 is generated; wherein the mass ratio of the added catalyst to the mixed material S1 is 0.01-0.1%; the esterification reaction conditions are as follows: the temperature is 160-245 ℃, the vacuum degree is 40-45KPa, and the reaction time is 1-3 hours;

placing the mixed material S2 into a reaction kettle (esterification kettle), and adding the catalyst mixed system prepared in the step S2 for esterification reaction until no water is generated; generating oligomer OM2, namely the compound shown in the formula (III);

wherein the mass ratio of the added catalyst to the mixed material S2 is 0.01-0.1%; the esterification reaction conditions are as follows: the temperature is 160-245 ℃, the vacuum degree is 40-45KPa, and the reaction time is 1-3 hours;

s4: prepolycondensation reaction

Placing the oligomer OM1 and the oligomer OM2 in a reaction kettle (pre-polycondensation kettle) to perform pre-polycondensation reaction to generate a pre-polycondensation product (namely a low-molecular-weight polyester copolymer); wherein the proportion of the mass of the oligomer OM1 to the sum of the masses of the oligomer OM1 and the oligomer OM2 is 0.1-50%; the pre-polycondensation reaction conditions are as follows: the temperature is 180 ℃ and 310 ℃, the vacuum degree is 1.5-2.5KPa, and the reaction time is 30-60 min.

S5: polycondensation reaction

Putting the pre-polycondensation product obtained in the step S4 into a reaction kettle (polycondensation reactor) for polycondensation reaction to generate a compound shown in the formula (I) (namely, a polyester block copolymer with high molecular weight); the polycondensation reaction conditions are as follows: the temperature is 180-; the intrinsic viscosity of the obtained polyester block copolymer is 0.5-1.0 dL/g;

s6: solid phase tackifying reaction

Feeding the polyester block copolymer particles obtained by the polycondensation reaction into a tackifying kettle, carrying out solid phase reaction at a set temperature of 100 ℃ and 260 ℃ under the vacuum state of 3-100Pa or the inert gas protection state with the flow rate of inert gas of 0.5-5L/[ min KG tackifying particles, and the reaction time of 4-36 hours; the resulting polyester block copolymer has an intrinsic viscosity of 0.8 to 2.0 dL/g.

The invention further optimizes the reaction conditions according to the characteristics of the raw materials. Specifically, the method comprises the following steps:

when the dicarboxylic acid in the step (1) is 2, 6-naphthalenedicarboxylic acid, the temperature range of the pre-polycondensation reaction is 250-310 ℃, the temperature range of the polycondensation reaction is 250-310 ℃, and the temperature range of the solid phase tackifying reaction is preferably 200-240 ℃.

When the dicarboxylic acid in the step (1) is terephthalic acid and the diol is 1, 4-Cyclohexanedimethanol (CHDM), the temperature range of the pre-polycondensation reaction is 280-310 ℃, the temperature of the polycondensation reaction is 280-310 ℃, and the temperature of the solid-phase tackifying reaction is preferably 240-260 ℃.

When the dicarboxylic acid in the step (1) is terephthalic acid, the diol is one or a mixture of two or more diols except 1, 4-Cyclohexanedimethanol (CHDM), the pre-polycondensation reaction temperature ranges from 200 ℃ to 250 ℃, the polycondensation reaction temperature ranges from 200 ℃ to 250 ℃, and the solid phase tackifying reaction temperature is preferably 180 ℃ to 220 ℃.

When the dicarboxylic acid in the step (1) is succinic acid, the temperature range of the pre-polycondensation reaction is 100-200 ℃, the temperature range of the polycondensation reaction is 100-200 ℃, and the temperature range of the solid-phase tackifying reaction is 100-110 ℃.

All the raw materials adopted by the invention can be purchased commercially.

The invention also protects the application of the polyester block copolymer or the polyester block copolymer prepared by the method in the preparation of fibers, films, bottles and cans and engineering plastics.

Compared with the prior art, the invention has the following advantages:

firstly, the polyester copolymer containing silicon units prepared by the invention has high intrinsic viscosity, directly reflects higher molecular weight and excellent mechanical property of the copolymer, and simultaneously endows the material with excellent low temperature resistance and lower surface tension, thereby greatly expanding the application range of the existing polyester.

Secondly, the polyester copolymer containing silicon units prepared by the invention is prepared by a direct polymerization method, and silicon molecules in the prepared polyester copolymer are uniformly distributed in the molecular chain of the polyester resin. Compared with a blending mode, the mode of blending the silicon rubber or the silicon resin and the polyester resin through a double-screw extruder has the advantages that the phenomenon of layering or incompatibility is generated due to the compatibility problem; in addition, if small molecule organosilicon molecules containing reactive groups are blended with polyester resin through a twin-screw extruder, the reaction is insufficient due to short residence time in the twin-screw extruder, so that more small molecules are remained in the final blend, and the volatile matters are higher.

Thirdly, the preparation method adopted by the invention respectively esterifies the silicon-containing monomer and the non-silicon-containing monomer and then polymerizes the monomers, so that the reaction is easier to control according to the requirements, and the polyester block copolymer with certain regularity is convenient to obtain; meanwhile, the silicon-containing monomer is esterified first, so that the reaction is easier to control.

Fourthly, the preparation method provided by the invention finally adopts a solid-phase polymerization mode with mild reaction conditions to synthesize the high molecular weight polyester copolymer which can not be prepared by direct polycondensation, thereby not only achieving the expected effect, but also avoiding the defects of large energy consumption, harsh reaction conditions, high requirements on equipment and difficult control of the process conditions of the product in the conventional polycondensation mode. The preparation method of the polyester copolymer provided by the invention is optimized on the basis of the existing polyester production method, is simple and convenient, and is easy to control and realize industrial production.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention. The examples do not show the specific techniques or conditions, according to the technical or conditions described in the literature in the field, or according to the product specifications. The reagents or instruments used are conventional products available from regular distributors, not indicated by the manufacturer.

The following detection methods:

the intrinsic viscosity: measured according to ASTM D445.

Impact strength: measured according to ASTM D256.

Content of terminal carboxyl group: measured according to GB/T14190-.

Constant temperature thermal weight loss of the solution: weighing a proper amount of sample, placing the sample in a heating furnace in an air atmosphere, wherein the initial temperature is room temperature, the heating rate is 20 ℃/min, the temperature is programmed to 260 ℃, and the temperature is kept for 120 min. And calculating the content of volatile matters in the sample through the curve change of the relation between the mass of the sample and the temperature.

Surface tension: measured according to GB/T14216-2008 standard.

Example 1 preparation of PBT copolyester containing silicon units

Preparing slurry: 1) terephthalic Acid (PTA) and 1, 4-Butanediol (BDO) respectively enter a slurry preparation tank U1 through a metering system, are uniformly stirred and are marked as slurry S1, wherein the PTA is 773G (the G meaning is mass unit G, the same below), and the BDO is 520G. 2) Alpha, omega-dicarboxyethyl polydimethylsiloxane (alpha, omega-dicarboxyethyl polydimethylsiloxane) and 1,4 Butanediol (BDO) are respectively fed into a slurry preparation tank U2 through a metering system and are uniformly stirred to be marked as slurry S2, wherein the alpha, omega-dicarboxyethyl polydimethylsiloxane is 210G, and the 1,4 Butanediol (BDO) is 30G.

Preparing a catalyst: adding 100G of 1, 4-Butanediol (BDO) and 158.9G of catalyst C (tetrabutyl titanate) into a preparation tank U3, heating and boiling for 2-3 hours under a vacuum state, wherein the vacuum degree is 20-30KPa, the temperature is 180 ℃, and transferring the prepared catalyst into a catalyst feeding tank after cooling.

Esterification reaction: and (3) delivering the slurry S1 in the slurry tank U1 into an esterification kettle E1 through a slurry pump, delivering the prepared catalyst C into the esterification kettle E1 through a gear pump, and carrying out esterification reaction under the action of the catalyst until no water is generated, so as to obtain the oligomer OM 1. The amount of the catalyst added was 0.05% based on the mass ratio C/S1 of the slurry. The reaction conditions of the esterification kettle are as follows: the temperature is 245 ℃, the vacuum degree is 42KPa, the reaction time is 2 hours, and the esterification rate reaches 99.2 percent.

Esterification reaction: and (3) delivering the slurry S2 in the slurry tank U2 into an esterification kettle E2 through a slurry pump, delivering the prepared catalyst into the esterification kettle E2 through a gear pump, carrying out esterification reaction under the action of the catalyst until no water is generated, and generating an oligomer OM 2. The amount of the catalyst added was 0.05% based on the mass ratio C/S2 of the slurry. The reaction conditions of the esterification kettle are as follows: the temperature is 245 ℃, the vacuum degree is 42KPa, the reaction time is 2 hours, and the esterification rate is 99 percent.

Pre-polycondensation reaction: the oligomers in the esterification kettles E1 and E2 are respectively fed into the pre-polycondensation kettle in proportion, wherein the proportion OM2/(OM1+ OM2) added by OM2 in the esterification kettle E2 is 10%. The initial polycondensation process in the esterification reaction is continuously carried out in a pre-polycondensation kettle, the pre-polycondensation reaction temperature is 245 ℃, the vacuum degree is-2 KPa, the reaction time is 40min, a low molecular weight polyester copolymer is generated, and the pre-polycondensation product enters a polycondensation reactor through a pre-polycondensation discharge pump, a pre-polycondensation discharge filter and a pre-polycondensation discharge cooler.

And (3) polycondensation reaction: and (3) feeding the pre-polycondensation product into a polycondensation reactor from the pre-polycondensation unit, and continuously reacting the prepolymer, wherein the polycondensation reaction temperature is 248 ℃, the vacuum degree is 120Pa, and the reaction time is 200min, so that the high-molecular-weight polyester block copolymer is generated. The polycondensation product enters a granulator system through a polycondensation discharge pump, a polymer viscometer, a polycondensation discharge filter and a polycondensation discharge distribution valve. Cooling and pelletizing to obtain the high molecular weight polyester block copolymer product. The intrinsic viscosity of the resulting polyester block copolymer was 0.61 dL/g.

The structure of the obtained polyester block copolymer is shown as the following formula:

solid-phase tackifying reaction: the polyester block copolymer particles obtained by the polycondensation reaction are sent into a tackifying kettle, and solid phase reaction is carried out at a set temperature under the vacuum state of 10Pa or the protection of inert gas, and the reaction time is 20 hours.

The intrinsic viscosity of the resulting polyester block copolymer was 0.92 dL/g. The temperature was set at 200 ℃.

Example 2 preparation of PBT copolyester containing silicon units

Preparing slurry: 1) terephthalic Acid (PTA) and 1,4 Butanediol (BDO) respectively enter a slurry preparation tank U1 through a metering system, are uniformly stirred and are marked as slurry S1, wherein the PTA is 773G, and the BDO is 520G. 2) Alpha, omega-dicarboxyethyl polydimethylsiloxane and 1,4 Butanediol (BDO) are respectively fed into a slurry preparation tank U2 through a metering system and are uniformly stirred to be marked as slurry S2, wherein the alpha, omega-dicarboxyethyl polydimethylsiloxane is 300G, and the 1,4 Butanediol (BDO) is 45G.

Pre-polycondensation reaction: the oligomers in the esterification kettles E1 and E2 are respectively fed into the pre-polycondensation kettle in proportion, wherein the proportion OM2/(OM1+ OM2) of OM2 in the esterification kettle E2 is 20%. The initial polycondensation process in the esterification reaction is continuously carried out in a pre-polycondensation kettle, the pre-polycondensation reaction temperature is 245 ℃, the vacuum degree is-2 KPa, the reaction time is 50min, a low molecular weight polyester copolymer is generated, and the pre-polycondensation product enters a polycondensation reactor through a pre-polycondensation discharge pump, a pre-polycondensation discharge filter and a pre-polycondensation discharge cooler.

And (3) polycondensation reaction: and (3) feeding the pre-polycondensation product into a polycondensation reactor from the pre-polycondensation unit, and continuously reacting the prepolymer, wherein the polycondensation reaction temperature is 248 ℃, the vacuum degree is 120Pa, and the reaction time is 200min, so that the high-molecular-weight polyester block copolymer is generated. The polycondensation product enters a granulator system through a polycondensation discharge pump, a polymer viscometer, a polycondensation discharge filter and a polycondensation discharge distribution valve. Cooling and pelletizing to obtain the high molecular weight polyester block copolymer product. The intrinsic viscosity of the resulting polyester block copolymer was 0.6 dL/g.

solid-phase tackifying reaction: the polyester block copolymer particles obtained by the polycondensation reaction are sent into a tackifying kettle, and solid phase reaction is carried out at a set temperature under the vacuum state of 10Pa or the protection of inert gas, and the reaction time is 25 hours.

The intrinsic viscosity of the resulting polyester block copolymer was 0.90 dL/g. The temperature was set at 200 ℃.

Example 3 preparation of PBT copolyester containing silicon units

Preparing slurry: 1) terephthalic Acid (PTA) and 1,4 Butanediol (BDO) respectively enter a slurry preparation tank U1 through a metering system, are uniformly stirred and are marked as slurry S1, wherein the PTA is 773G, and the BDO is 520G. 2) Alpha, omega-dicarboxyethyl polydimethylsiloxane and 1,4 Butanediol (BDO) are respectively fed into a slurry preparation tank U2 through a metering system and are uniformly stirred to be marked as slurry S2, wherein the alpha, omega-dicarboxyethyl polydimethylsiloxane is 420G, and the 1,4 Butanediol (BDO) is 60G.

Pre-polycondensation reaction: the oligomers in esterification kettles E1 and E2 are respectively fed into the pre-polycondensation kettle in proportion, wherein the proportion OM2/(OM1+ OM2) of OM2 in esterification kettle E2 is 30%. The initial polycondensation process in the esterification reaction is continuously carried out in a pre-polycondensation kettle, the pre-polycondensation reaction temperature is 245 ℃, the vacuum degree is-2 KPa, the reaction time is 50min, a low molecular weight polyester copolymer is generated, and the pre-polycondensation product enters a polycondensation reactor through a pre-polycondensation discharge pump, a pre-polycondensation discharge filter and a pre-polycondensation discharge cooler.

And (3) polycondensation reaction: and (3) feeding the pre-polycondensation product into a polycondensation reactor from the pre-polycondensation unit, and continuously reacting the prepolymer, wherein the polycondensation reaction temperature is 248 ℃, the vacuum degree is 120Pa, and the reaction time is 200min, so that the high-molecular-weight polyester block copolymer is generated. The polycondensation product enters a granulator system through a polycondensation discharge pump, a polymer viscometer, a polycondensation discharge filter and a polycondensation discharge distribution valve. Cooling and pelletizing to obtain the high molecular weight polyester block copolymer product. The intrinsic viscosity of the resulting polyester block copolymer was 0.55 dL/g.

solid-phase tackifying reaction: the polyester block copolymer particles obtained by the polycondensation reaction are sent into a tackifying kettle, and solid phase reaction is carried out at a set temperature under the vacuum state of 10Pa or the protection of inert gas, and the reaction time is 30 hours.

The intrinsic viscosity of the resulting polyester block copolymer was 0.88 dL/g. The temperature was set at 200 ℃.

Example 4 preparation of PBT copolyester containing silicon units

Preparing slurry: 1) terephthalic Acid (PTA) and 1,4 Butanediol (BDO) respectively enter a slurry preparation tank U1 through a metering system, are uniformly stirred and are marked as slurry S1, wherein the PTA is 773G, and the BDO is 520G. 2) Alpha, omega-dicarboxyethyl polydimethylsiloxane and 1,4 Butanediol (BDO) are respectively fed into a slurry preparation tank U2 through a metering system and are uniformly stirred to be marked as slurry S2, wherein alpha, omega-dicarboxyethyl polydimethylsiloxane is 100G, and 1,4 Butanediol (BDO) is 20G.

Pre-polycondensation reaction: the oligomers in esterification kettles E1 and E2 are respectively fed into the pre-polycondensation kettle in proportion, wherein the proportion OM2/(OM1+ OM2) added by OM2 in esterification kettle E2 is 5%. The initial polycondensation process in the esterification reaction is continuously carried out in a pre-polycondensation kettle, the pre-polycondensation reaction temperature is 245 ℃, the vacuum degree is-2 KPa, the reaction time is 40min, a low molecular weight polyester copolymer is generated, and the pre-polycondensation product enters a polycondensation reactor through a pre-polycondensation discharge pump, a pre-polycondensation discharge filter and a pre-polycondensation discharge cooler.

And (3) polycondensation reaction: and (3) feeding the pre-polycondensation product into a polycondensation reactor from the pre-polycondensation unit, and continuously reacting the prepolymer, wherein the polycondensation reaction temperature is 248 ℃, the vacuum degree is 120Pa, and the reaction time is 200min, so that the high-molecular-weight polyester block copolymer is generated. The polycondensation product enters a granulator system through a polycondensation discharge pump, a polymer viscometer, a polycondensation discharge filter and a polycondensation discharge distribution valve. Cooling and pelletizing to obtain the high molecular weight polyester block copolymer product. The intrinsic viscosity of the resulting polyester block copolymer was 0.65 dL/g.

The intrinsic viscosity of the resulting polyester block copolymer was 0.93 dL/g. The temperature was set at 200 ℃.

Comparative example 1 preparation of PBT polyester containing no silicon units

Preparing slurry: 1) terephthalic Acid (PTA) and 1,4 Butanediol (BDO) respectively enter a slurry preparation tank U1 through a metering system, are uniformly stirred and are marked as slurry S1, wherein the PTA is 773G, and the BDO is 520G.

Pre-polycondensation reaction: and (2) feeding the oligomer in the esterification kettle E1 into a pre-polycondensation kettle, continuously carrying out the initial polycondensation process in the esterification reaction in the pre-polycondensation kettle, wherein the pre-polycondensation reaction temperature is 245 ℃, the vacuum degree is-2 KPa, the reaction time is 40min, generating a low-molecular-weight polyester copolymer, and feeding the pre-polycondensation product into the polycondensation reactor through a pre-polycondensation discharge pump, a pre-polycondensation discharge filter and a pre-polycondensation discharge cooler.

And (3) polycondensation reaction: and (3) feeding the pre-polycondensation product into a polycondensation reactor from the pre-polycondensation unit, and continuously reacting the prepolymer, wherein the polycondensation reaction temperature is 248 ℃, the vacuum degree is 120Pa, and the reaction time is 200min, so that the high-molecular-weight polyester block copolymer is generated. The polycondensation product enters a granulator system through a polycondensation discharge pump, a polymer viscometer, a polycondensation discharge filter and a polycondensation discharge distribution valve. Cooling and pelletizing to obtain the high molecular weight polyester block copolymer product. The intrinsic viscosity of the resulting polyester block copolymer was 0.75 dL/g.

The intrinsic viscosity of the resulting polyester block copolymer was 0.95 dL/g. The temperature was set at 200 ℃.

Example 5 preparation of PCT copolyester containing silicon units

Preparing slurry: 1) terephthalic Acid (PTA) and 1, 4-Cyclohexanedimethanol (CHDM) respectively enter a slurry preparation tank U1 through a metering system, are uniformly stirred, and are marked as slurry S1, wherein PTA is 773G, and CHDM is 670G. 2) Alpha, omega-dicarboxyethyl polydimethylsiloxane (alpha, omega-dicarboxyethyl polydimethylsiloxane) and 1, 4-Cyclohexanedimethanol (CHDM) used in the slurry 1) enter a slurry preparation tank U2 through a metering system respectively, are uniformly stirred and are marked as slurry S2, wherein the alpha, omega-dicarboxyethyl polydimethylsiloxane is 100G, and the 1, 4-Cyclohexanedimethanol (CHDM) is 30G.

Preparing a catalyst: adding 128.89G of 1, 4-Cyclohexanedimethanol (CHDM) and 158.9G of catalyst C (tetrabutyl titanate) into a preparation tank U3, slowly heating to 200 ℃, heating and boiling for 2-3 hours in a vacuum state, wherein the vacuum degree is 20-30KPa, and transferring the prepared catalyst into a catalyst feeding tank after cooling.

Esterification reaction: and (3) delivering the slurry S1 in the slurry tank U1 into an esterification kettle E1 through a slurry pump, delivering the prepared catalyst C into the esterification kettle E1 through a gear pump, and carrying out esterification reaction under the action of the catalyst until no water is generated, so as to obtain the oligomer OM 1. The amount of the catalyst added was 0.05% based on the mass ratio C/S1 of the slurry. The reaction conditions of the esterification kettle are as follows: the temperature is 280 ℃, the vacuum degree is 42KPa, the reaction time is 2 hours, and the esterification rate reaches 99.1 percent.

Pre-polycondensation reaction: the oligomers in esterification kettles E1 and E2 are respectively fed into the pre-polycondensation kettle in proportion, wherein the proportion OM2/(OM1+ OM2) added by OM2 in esterification kettle E2 is 5%. The initial polycondensation process in the esterification reaction is continuously carried out in a pre-polycondensation kettle, the pre-polycondensation reaction temperature is 300 ℃, the vacuum degree is-2 KPa, the reaction time is 40min, a low molecular weight polyester copolymer is generated, and the pre-polycondensation product enters a polycondensation reactor through a pre-polycondensation discharge pump, a pre-polycondensation discharge filter and a pre-polycondensation discharge cooler.

And (3) polycondensation reaction: and (3) feeding the pre-polycondensation product into a polycondensation reactor from the pre-polycondensation unit, and continuously reacting the prepolymer, wherein the polycondensation reaction temperature is 300 ℃, the vacuum degree is 120Pa, and the reaction time is 200min, so that the high-molecular-weight polyester block copolymer is generated. The polycondensation product enters a granulator system through a polycondensation discharge pump, a polymer viscometer, a polycondensation discharge filter and a polycondensation discharge distribution valve. Cooling and pelletizing to obtain the high molecular weight polyester block copolymer product. The intrinsic viscosity of the resulting polyester block copolymer was 0.56 dL/g.

The intrinsic viscosity of the resulting polyester block copolymer was 0.82 dL/g. The temperature was set at 260 ℃.

Comparative example 2 preparation of PCT polyester containing no silicon units

Preparing slurry: 1) terephthalic Acid (PTA) and 1, 4-Cyclohexanedimethanol (CHDM) respectively enter a slurry preparation tank U1 through a metering system, are uniformly stirred, and are marked as slurry S1, wherein PTA is 773G, and CHDM is 670G.

Pre-polycondensation reaction: and (2) feeding the low polymer in the esterification kettle E1 into a pre-polycondensation kettle, continuously carrying out the polycondensation process started in the esterification reaction in the pre-polycondensation kettle, wherein the pre-polycondensation reaction temperature is 300 ℃, the vacuum degree is-2 KPa, the reaction time is 40min, generating a low-molecular-weight polyester copolymer, and feeding the pre-polycondensation product into the polycondensation reactor through a pre-polycondensation discharge pump, a pre-polycondensation discharge filter and a pre-polycondensation discharge cooler.

And (3) polycondensation reaction: and (3) feeding the pre-polycondensation product into a polycondensation reactor from the pre-polycondensation unit, and continuously reacting the prepolymer, wherein the polycondensation reaction temperature is 300 ℃, the vacuum degree is 120Pa, and the reaction time is 200min, so that the high-molecular-weight polyester block copolymer is generated. The polycondensation product enters a granulator system through a polycondensation discharge pump, a polymer viscometer, a polycondensation discharge filter and a polycondensation discharge distribution valve. Cooling and pelletizing to obtain the high molecular weight polyester block copolymer product. The intrinsic viscosity of the resulting polyester block copolymer was 0.61 dL/g.

The intrinsic viscosity of the resulting polyester block copolymer was 0.85 dL/g. The temperature was set at 260 ℃.

Example 6 preparation of PBN copolyester containing silicon units

Preparing slurry: 1) 2, 6-naphthalenedicarboxylic acid (NDA) and 1, 4-Butanediol (BDO) were fed into a slurry preparation tank U1 through a metering system and stirred uniformly as slurry S1, wherein NDA was 997G and BDO was 520G. 2) Alpha, omega-dicarboxyethyl polydimethylsiloxane and 1,4 Butanediol (BDO) are respectively fed into a slurry preparation tank U2 through a metering system and are uniformly stirred to be marked as slurry S2, wherein the alpha, omega-dicarboxyethyl polydimethylsiloxane is 80G, and the 1,4 Butanediol (BDO) is 20G.

Esterification reaction: and (3) delivering the slurry S1 in the slurry tank U1 into an esterification kettle E1 through a slurry pump, delivering the prepared catalyst C into the esterification kettle E1 through a gear pump, and carrying out esterification reaction under the action of the catalyst until no water is generated, so as to obtain the oligomer OM 1. The amount of the catalyst added was 0.05% based on the mass ratio C/S1 of the slurry. The reaction conditions of the esterification kettle are as follows: the temperature is 265 ℃, the vacuum degree is 42KPa, the reaction time is 2 hours, and the esterification rate reaches 99.2 percent.

Esterification reaction: and (3) delivering the slurry S2 in the slurry tank U2 into an esterification kettle E2 through a slurry pump, delivering the prepared catalyst into the esterification kettle E2 through a gear pump, carrying out esterification reaction under the action of the catalyst until no water is generated, and generating an oligomer OM 2. The amount of the catalyst added was 0.05% based on the mass ratio C/S2 of the slurry. The reaction conditions of the esterification kettle are as follows: the temperature is 265 ℃, the vacuum degree is 42KPa, the reaction time is 2 hours, and the esterification rate is 98.6 percent.

Pre-polycondensation reaction: the oligomers in esterification kettles E1 and E2 are respectively fed into the pre-polycondensation kettle in proportion, wherein the proportion OM2/(OM1+ OM2) added by OM2 in esterification kettle E2 is 5%. The initial polycondensation process in the esterification reaction is continuously carried out in a pre-polycondensation kettle, the pre-polycondensation reaction temperature is 265 ℃, the vacuum degree is-2 KPa, the reaction time is 40min, a low molecular weight polyester copolymer is generated, and the pre-polycondensation product enters a polycondensation reactor through a pre-polycondensation discharge pump, a pre-polycondensation discharge filter and a pre-polycondensation discharge cooler.

And (3) polycondensation reaction: and (3) feeding the pre-polycondensation product into a polycondensation reactor from the pre-polycondensation unit, and continuously reacting the prepolymer, wherein the polycondensation reaction temperature is 268 ℃, the vacuum degree is 120Pa, and the reaction time is 200min, so that the high-molecular-weight polyester block copolymer is generated. The polycondensation product enters a granulator system through a polycondensation discharge pump, a polymer viscometer, a polycondensation discharge filter and a polycondensation discharge distribution valve. Cooling and pelletizing to obtain the high molecular weight polyester block copolymer product. The intrinsic viscosity of the resulting polyester block copolymer was 0.66 dL/g.

The intrinsic viscosity of the resulting polyester block copolymer was 0.79 dL/g. The temperature was set at 200 ℃.

Comparative example 3 preparation of PBN polyester without silicon units

Preparing slurry: 1) 2, 6-naphthalenedicarboxylic acid (NDA) and 1, 4-Butanediol (BDO) were fed into a slurry preparation tank U1 through a metering system and stirred uniformly as slurry S1, wherein NDA was 997G and BDO was 520G.

Pre-polycondensation reaction: and (2) feeding the low polymer in the esterification kettle E1 into a pre-polycondensation kettle, continuously carrying out the initial polycondensation process in the esterification reaction in the pre-polycondensation kettle, wherein the pre-polycondensation reaction temperature is 265 ℃, the vacuum degree is-2 KPa, the reaction time is 40min, generating a low-molecular-weight polyester copolymer, and feeding the pre-polycondensation product into the polycondensation reactor through a pre-polycondensation discharge pump, a pre-polycondensation discharge filter and a pre-polycondensation discharge cooler.

And (3) polycondensation reaction: and (3) feeding the pre-polycondensation product into a polycondensation reactor from the pre-polycondensation unit, and continuously reacting the prepolymer, wherein the polycondensation reaction temperature is 268 ℃, the vacuum degree is 120Pa, and the reaction time is 200min, so that the high-molecular-weight polyester block copolymer is generated. The polycondensation product enters a granulator system through a polycondensation discharge pump, a polymer viscometer, a polycondensation discharge filter and a polycondensation discharge distribution valve. Cooling and pelletizing to obtain the high molecular weight polyester block copolymer product. The intrinsic viscosity of the resulting polyester block copolymer was 0.75 dL/g.

The intrinsic viscosity of the resulting polyester block copolymer was 0.85 dL/g. The temperature was set at 200 ℃.

Examples of the experiments

The analytical characterization and evaluation results of the polyester block copolymers prepared in examples 1 to 6 and comparative examples 1 to 3 are shown in tables 1 to 3 below.

TABLE 1

TABLE 2

Performance of	Unit of	Comparative example No. 2#	Example 5#
				Intrinsic viscosity	DL/g	0.85	0.82
Content of terminal carboxyl groups	Mmol/Kg	18	17
				Impact Strength (23 ℃ C.)	KJ/m²	4	16
Impact Strength (-40 ℃ C.)	KJ/m²	2	12
				Thermal weight loss	％	1.6	1.5
Surface tension	mN/m	39	27

TABLE 3

Performance of	Unit of	Comparative example No. 3#	Example 6#
				Intrinsic viscosity	DL/g	0.85	0.79
Content of terminal carboxyl groups	Mmol/Kg	17	16
				Impact Strength (23 ℃ C.)	KJ/m²	4	18
Impact Strength (-40 ℃ C.)	KJ/m²	3	13
				Thermal weight loss	％	1.7	1.6
Surface tension	mN/m	42	27

As can be seen from tables 1-3, the polyester block copolymer prepared by the invention has lower surface tension, better low-temperature impact resistance and lower thermal weight loss rate, makes up the performance deficiency of common polyester resin and expands the application field of the polyester block copolymer.

Although the invention has been described in detail hereinabove by way of general description, specific embodiments and experiments, it will be apparent to those skilled in the art that many modifications and improvements can be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. A polyester block copolymer having the following structure represented by the following formula (I):

A_n-B_t (I)

in formula (I):

the B block structure is shown as the formula (II):

One or more of the above; s is an integer greater than 1;

in the block copolymer, n is an integer greater than 1, and t is an integer greater than 1;

the polyester block copolymer meets the condition that the sum of the percentage of the A block to the total mass of the copolymer and the percentage of the B block to the total mass of the copolymer is 100 percent;

the mass of the B block accounts for 10-50% of the total mass of the copolymer.

2. The polyester block copolymer according to claim 1, wherein the mass of the B block is 10 to 30% based on the total mass of the copolymer.

3. The polyester block copolymer according to claim 2, wherein the mass of the B block is 10 to 20% based on the total mass of the copolymer.

4. The polyester block copolymer according to claim 3, wherein the mass of the B block is 10 to 15% based on the total mass of the copolymer.

5. The polyester block copolymer according to any one of claims 1 to 4, wherein in the A block, the aromatic dicarboxylic acid is selected from one or more of terephthalic acid, isophthalic acid and naphthalene dicarboxylic acid; the aliphatic dicarboxylic acid is selected from one or more of succinic acid, adipic acid and suberic acid; the aliphatic diol is one or more selected from ethylene glycol, propylene glycol, butanediol, hexanediol and 1, 4-cyclohexanedimethanol.

6. The polyester block copolymer of claim 5, wherein in the A block: the dicarboxylic acid is terephthalic acid, and the dihydric alcohol is ethylene glycol; or the dicarboxylic acid is terephthalic acid, and the dihydric alcohol is 1, 3-propanediol; or the dicarboxylic acid is terephthalic acid, and the dihydric alcohol is 1, 4-butanediol; or the dicarboxylic acid is terephthalic acid, and the diol is 1, 4-cyclohexanedimethanol; or the dicarboxylic acid is 2, 6-naphthalene dicarboxylic acid, and the diol is ethylene glycol; or the dicarboxylic acid is 2, 6-naphthalenedicarboxylic acid, and the diol is 1, 4-butanediol; or the dicarboxylic acid is 1, 4-succinic acid, and the dihydric alcohol is 1, 4-butanediol; or the dicarboxylic acid is terephthalic acid, and the dihydric alcohol is ethylene glycol and 1, 4-cyclohexanedimethanol.

7. The polyester block copolymer according to any one of claims 1 to 4, wherein 1 < s.ltoreq.100 in the B block;

and/or, R₄、R₅The structure of (2) is the same.

8. The polyester block copolymer according to claim 7, wherein 1 < s.ltoreq.50 in the B block.

9. The polyester block copolymer according to claim 8, wherein 1 < s.ltoreq.30 in the B block.

10. The polyester block copolymer of claim 7, wherein R is R₄And R₅Are all methyl.

11. The polyester block copolymer according to any one of claims 1 to 4, wherein the intrinsic viscosity of the polyester block copolymer is 0.6 to 2.0 dL/g.

12. The polyester block copolymer of claim 11, wherein the intrinsic viscosity of the polyester block copolymer is from 0.79 to 1.33 dL/g.

13. The polyester block copolymer according to any one of claims 1 to 4, wherein the polyester block copolymer is selected from one or more of the following structures:

14. a method for preparing a polyester block copolymer, comprising the steps of:

(4) placing the pre-polycondensation product obtained in the step (3) into a reaction kettle, and carrying out polycondensation reaction to obtain a polyester block copolymer;

in the step (3), the proportion of the product obtained in the step (2) to the sum of the product dosage of the steps (1) and (2) is 10-50%.

15. The method according to claim 14, wherein the diol in step (2) is one or more selected from ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 6-hexanediol, and 1, 4-cyclohexanedimethanol.

16. The method according to claim 14, further comprising subjecting the product obtained in step (4) to solid-phase tackifying reaction to obtain a polyester block copolymer having an intrinsic viscosity of 0.8 to 2.0 dL/g.

17. The method according to claim 16, further comprising subjecting the product obtained in step (4) to solid-phase tackifying reaction to obtain a polyester block copolymer having an intrinsic viscosity of 0.79 to 1.33 dL/g.

18. The method according to any one of claims 14 to 17, wherein in the step (1), the molar ratio of the dicarboxylic acid to the diol is 1:1 to 1: 1.5;

and/or in the step (2), the molar ratio of the compound shown in the formula (III) to the dihydric alcohol is 1: 1.2-1: 1.5;

and/or in the step (3), the proportion of the product dosage obtained in the step (2) in the sum of the product dosages in the steps (1) and (2) is 10-30%.

19. The method for preparing the compound of claim 18, wherein the product obtained in the step (2) accounts for 10-20% of the sum of the product obtained in the step (1) and the product obtained in the step (2).

20. The method for preparing the compound of the claim 19, wherein the proportion of the product obtained in the step (2) to the sum of the product obtained in the step (1) and the product obtained in the step (2) is 10 to 15 percent.

21. The production method according to claim 16 or 17, wherein the pre-polycondensation reaction conditions in step (3) are: the temperature is 180-310 ℃, and the vacuum degree is 1.5-2.5 KPa; the polycondensation reaction conditions in the step (4) are as follows: the temperature is 180-310 ℃, and the vacuum degree is 100-200 Pa.

22. The method as claimed in claim 21, wherein the temperature of the solid phase adhesion-promoting reaction is 100-260 ℃.

23. The method according to claim 21, wherein when the dicarboxylic acid in the step (1) is 2, 6-naphthalenedicarboxylic acid, the pre-polycondensation reaction temperature is 250 to 310 ℃ and the polycondensation reaction temperature is 250 to 310 ℃;

when the dicarboxylic acid in the step (1) is terephthalic acid and the diol is 1, 4-cyclohexanedimethanol, the temperature range of the pre-polycondensation reaction is 280-310 ℃, and the temperature of the polycondensation reaction is 280-310 ℃;

when the dicarboxylic acid in the step (1) is terephthalic acid, the dihydric alcohol is one or a mixture of more than two dihydric alcohols except 1, 4-cyclohexanedimethanol, the pre-polycondensation reaction temperature ranges from 200 ℃ to 250 ℃, and the polycondensation reaction temperature ranges from 200 ℃ to 250 ℃;

24. The method according to claim 23, wherein when the dicarboxylic acid in the step (1) is 2, 6-naphthalenedicarboxylic acid, the solid phase thickening reaction temperature is 200 to 240 ℃.

25. The method according to claim 23, wherein when the dicarboxylic acid in the step (1) is terephthalic acid and the diol is 1, 4-cyclohexanedimethanol, the solid phase viscosity increase reaction temperature is 240 to 260 ℃.

26. The method according to claim 23, wherein when the dicarboxylic acid in the step (1) is terephthalic acid, the diol is one diol other than 1, 4-cyclohexanedimethanol, or a mixture of two or more diols, the solid phase tackifying reaction temperature is 180 to 220 ℃.

27. A polyester block copolymer produced by the production method according to any one of claims 14 to 26.

28. Use of the polyester block copolymer according to any one of claims 1 to 13 or 27 for the production of fibers, films, bottles and cans, engineering plastics.