Polyester functional masterbatch and preparation method thereof

Abstract

The polyester functional master batch is prepared by direct esterification of ethylene glycol, silicon sol and terephthalic acid; the particle size of the silica functional particles in the polyester functional master batch is 8-65 nm; and the content of the silica functional particles in the polyester functional master batch is 2000-10000 ppm. The polyester functional master batch is prepared in situ by direct esterification, and the particle size of the functional particles in the prepared polyester functional master batch is small, and the dispersibility is excellent, so that the performance of the polyester master batch is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of polyester functional master batch and its preparation method, belong to polyester film technical field. BACKGROUND

[0002] Optical polyester (PET) film is widely used in new display industry field, its excellent comprehensive performance, especially the outstanding optical properties such as light transmittance, haze, definition, with the rapid development of flat panel display, energy saving and emission reduction and photovoltaic power generation and other new energy, more and more show its unique advantages.The important determinant of optical film optical properties is the crystallinity of optical film.In the processing of polyester film, crystal form and crystallinity change constantly, which needs to be strictly controlled.Usually for this purpose, the main methods of PET performance control are three:(1) blending with polymer: PET is blended with some polymers to prepare a uniform composite to effectively improve the crystallization performance or mechanical properties of PET.(2) Copolymerization: one or more components are added to PET, which introduces new structural units into the molecular chain, eventually preparing a new polymer, which can also improve the performance of PET.(3) Add crystallization nucleating agent or nucleating promoter: adding crystallization nucleating agent can quickly improve the crystallization rate of PET, improve the crystallization performance of PET, make the organization structure of PET uniform, so as to improve the related performance of PET.This is one of the simplest and most effective methods.At present, the industry often uses double screw blending method to produce functional master batch through this method, and the nucleating agent powder or dispersion liquid is simply physically mixed in the molten state to realize the addition of particles.However, in the production process, large particle size particles have significant addition effect, which can obviously improve the self-adhesion of polyester film and other problems, but the addition of small particle size particles, especially one hundred nanometer below nanometer particles often has the problems of poor dispersibility and agglomeration, and there is no better solution at present.

[0003] In the prior art, researchers have done a lot of work to improve this situation. CN101333329A discloses a "preparation method of low-haze biaxially stretched polyester film polyester", which is prepared by adding barium sulfate with similar refractive index to polyester during polyester synthesis to prepare optical polyester masterbatch, the haze is reduced from 6% to 7% to 2% to 3%, and the friction coefficient is comparable; (3) CN101284435A discloses "a kind of transparent polyester film and its manufacturing method", which is prepared by compounding nano and micro inorganic opening agent, including silica, barium sulfate, talc, kaolin, etc. Optical polyester masterbatch, nano particles act as nucleating agent, improve the crystallization rate, reduce the size of spherulite, further improve the optical performance of the film, and micro inorganic particles solve the winding and slitting of polyester film. Although there have been the above related reports to improve the application effect of optical polyester masterbatch in the film, the application of micro inorganic opening agent in thin optical film such as dry film for printed circuit board, release film for ceramic capacitor and release film and protective film for polarizing sheet will cause the problems of poor surface flatness and high haze of the film. At the same time, there are problems such as immature nanometer treatment method of inorganic particles, poor dispersion uniformity of nano particles in polyester, and great influence of micro and nano particle size, addition amount and micro-nano ratio on the optical performance and opening characteristics of polyester, etc. There is still great difficulty in industrial production.

[0004] Patent CN113956448A uses large particle size silica sol prepared by hydrolysis method to add to the reaction system during the synthesis reaction, and the particles act as anti-blocking agent in the masterbatch to improve the performance. The patent provides an application of large particle size particles as opening agent in the synthesis of functional masterbatch, which realizes the stable distribution of large particle size particles in the masterbatch, but cannot significantly improve the crystallinity. The particle synthesis hydrolysis method used in the preparation of functional masterbatch is suitable for the synthesis of large particle size particles, but cannot be used for the synthesis and preparation of small particle size functional particle masterbatch.

[0005] In summary, the functional particles in the current polyester functional masterbatch usually have large particle size and high addition amount, which reduces the light transmittance and affects the optical performance; the dispersion of nano particles is poor, which easily forms large particles and causes crystal points in optical film, seriously affecting the performance of optical film; the current mainstream application of double screw extrusion method can only be used to prepare functional masterbatch with high particle addition amount (>10000ppm); the addition of particles during the synthesis reaction process is complex, and the reaction system has high temperature and high activity, which easily causes poor dispersion effect during the addition of particles. In the existing particle solution addition method, some stabilizers and other additives are often added to maintain the dispersion of particles, which has a certain influence on the final performance of the masterbatch. SUMMARY

[0006] The application provides a polyester functional master batch and a preparation method thereof.

[0007] The application solves the technical problems by adopting the technical solutions as follows:

[0008] The polyester functional master batch is prepared by esterification and polycondensation of ethylene glycol silica sol, ethylene glycol and terephthalic acid through a direct esterification method, PET synthesis is performed in situ through the direct esterification method, and the particle addition amount can be effectively controlled; the particle size of the silica functional particles in the polyester functional master batch is 8nm to 65nm, the small particle size functional particles have little influence on the haze, the light transmittance is improved, and the crystallinity is effectively improved; the content of the silica functional particles in the polyester functional master batch is 2000ppm to 10000ppm, the low concentration control is specific to the in-situ polymerization method, and the problem that a double-screw extrusion method cannot be used to prepare a low-concentration master batch with good dispersibility is solved.

[0009] The polyester functional master batch has a specific viscosity of 0.66±0.05dL / g, a carboxyl end group content of ≤24.0±3.0mol / t and a diethylene glycol content of 1.0±0.15wt%.

[0010] The application further provides a preparation method of the polyester functional master batch.

[0011] S1. Preparation of small particle size silica sol

[0012] Sodium silicate solution and water are added into a reaction container in a proportion of 1:(3-6) and stirred uniformly to obtain a mixed solution A; the mixed solution A is subjected to ion exchange through a chromatographic column filled with hydrogen type strong acid cation exchange resin to obtain a solution B; under room temperature conditions, methyl sodium silicate solution, sodium silicate solution and water are added into the reactor in a proportion of 1:(3-5):(7-9), and after being uniformly mixed, a solution C is obtained; under a temperature of 75-90℃, the obtained solution B is slowly added into the solution C, and after the addition is completed, the solution is kept for 1-3h to obtain a sol D;

[0013] According to the preparation method in step S1, the functional particles with a particle size of 8nm to 65nm can be synthesized. The particles with this particle size level can effectively increase the nucleation center in the PET film production process, improve the crystallinity condition of the polyester film, and further improve the performance of the PET film. Meanwhile, since the particle size level is in the order of hundreds of nanometers, the particle size has no influence on the haze of the PET film, and the light transmittance and other optical properties of the PET film are ensured under the condition of adding the functional particles.

[0014] S2. Preparation of ethylene glycol silica sol

[0015] The sol D obtained in step S1 is subjected to solvent replacement by distillation method to replace the solvent with ethylene glycol, and is concentrated by ultrafiltration method to obtain an ethylene glycol solvent silica sol E with a concentration of 10-30 wt%;

[0016] Step S2 realizes preparation of the ethylene glycol dispersed small-particle-size silica sol, ensures stable dispersion of the functional particles in the reaction system, and effectively improves the poor dispersibility problem faced by the powder dispersion method. No additional catalyst or additive is added in the synthesis process of the ethylene glycol silica sol, thereby avoiding the influence of the excess substances on the subsequent synthesis reaction.

[0017] S3. Preparation of the polyester functional masterbatch:

[0018] 10-30 parts by mass of the ethylene glycol solvent silica sol E, 500 parts by mass of terephthalic acid, 270-290 parts by mass of ethylene glycol, 0.2-0.3 parts by mass of a catalyst, and 0.08-0.09 parts by mass of a stabilizer are added to a reaction kettle, and after being uniformly stirred, the mixture is heated to 230-265℃, and esterification reaction is performed for 2-4 h; then all the materials in the reaction kettle are subjected to polycondensation reaction at a temperature of 265-285℃ and under vacuum to a pressure of less than 160 Pa for 2-5 h, and after the reaction is completed, the material is collected after cooling and is cut into particles to obtain the polyester functional masterbatch.

[0019] Step S3 is the synthesis process of the direct esterification method of the functional masterbatch, the ethylene glycol silica sol is directly added to the reaction system as a reactant in the reaction process, and the system has good stability, and the particles can be stably dispersed in the reaction system. In this step, no material needs to be added to the reaction system in the middle of the reaction, and no reaction kettle transfer is needed, and the functional masterbatch can be synthesized and prepared at one time according to the steps. The in-situ synthesis method solves the problems of poor dispersion and high concentration faced by the double-screw extrusion method, has high control accuracy, and the particle addition amount is accurate.

[0020] In the above method for preparing the polyester functional masterbatch, the dropping speed of the solution B in step S1 is 0.4-0.8 mL / min. The dropping speed and the reaction time can be matched to control the particle size.

[0021] In the above method for preparing the polyester functional masterbatch, the catalyst in step S3 is one or a combination of two or more of antimony trioxide, ethylene glycol antimony, or antimony acetate.

[0022] In the above method for preparing the polyester functional masterbatch, the stabilizer in step S3 is one of trimethyl phosphate or triphenyl phosphate.

[0023] The polyester functional masterbatch prepared by the method can be used to prepare a release film base film, and the preparation process is as follows: the polyester functional masterbatch prepared by the method is added to a polyester masterbatch, and a biaxial stretching is performed to obtain the release film base film, wherein the addition amount of the polyester functional masterbatch is 200 ppm-2000 ppm.

[0024] The beneficial effects of the present application are:

[0025] 1. By self-preparing small particle size silica functional particles, small particle size silica sol can be effectively prepared according to the specific conditions of the synthesis reaction system. The small particle size silica functional particles have small and controllable particle size, and the addition amount is controllable. The small particle size silica functional particles are monodispersed and can be well dispersed in solvents and reaction systems, effectively solving the problems such as particle agglomeration that are prone to occur in PET synthesis.

[0026] 2. The synthesis of small particle size and low concentration silica functional particle masterbatch can effectively improve the practical application of polyester functional masterbatch in optical film preparation. The small particle size has low influence on haze, effectively improving the light transmittance. The small particle size silica functional particles can act as nucleation centers, improving the crystallinity in PET stretch film production and improving the performance of optical films.

[0027] 3. The application of small particle size silica functional particles is suitable for ultra-high requirements of low surface roughness, and will not affect the surface roughness of optical films due to the large protrusions of particles. This type of optical film can be effectively applied to polarizing sheet release film and sheet type multilayer ceramic capacitor MLCC release film base film.

[0028] 4. The key difference between the present method and the existing polyester functional masterbatch preparation method lies in the self-preparation of functional particles and the application of in-situ synthesis method for the synthesis of functional masterbatch. The double screw extrusion method disperses the functional particle dispersion liquid in the molten masterbatch by physical stirring. In order to ensure the dispersion degree of the particles, high concentration dispersion liquid must be used, which often leads to poor dispersibility and increases the possibility of agglomeration. The in-situ synthesis method solves the problems of poor dispersion and high concentration faced by the double screw extrusion method, with high control accuracy and accurate particle addition amount. In the synthesis process, the uniformly dispersed silica functional particle sol is used as the raw material, and the particles are fully dispersed and uniform before the synthesis reaction. During the polyester synthesis process, only the progress of the synthesis reaction needs to be concerned, and phenomena such as particle agglomeration and poor dispersion do not occur. In addition, the in-situ synthesis method is a chemical preparation method, which can be applied to the synthesis process of polyester masterbatch. The functional particles can be specifically synthesized according to the specific requirements of the masterbatch reaction system, and the combination of functional groups and groups can be used to prepare specific functional masterbatch. This is not available for the double screw physical mixing method. The self-preparation of particles can prepare functional particles in real time according to the specific requirements of the masterbatch reaction system. During the synthesis reaction, the functional particle dispersion liquid is directly used as a reactant for synthesis reaction, and there is no need for intermediate addition or reaction kettle conversion during the masterbatch preparation process, greatly reducing the operation difficulty and increasing the safety of production and preparation. DETAILED DESCRIPTION

[0029] The present application will be further described below in conjunction with examples.

[0030] Example 1

[0031] S1. Preparation of 8 nm ethylene glycol silica sol

[0032] A mixture solution A was prepared by adding sodium silicate solution and water in a ratio of 1:6 in a reaction vessel and stirring uniformly; solution B was obtained by ion exchange of the mixture solution A through a chromatographic column filled with hydrogen type strong acid cation exchange resin; solution C was obtained by adding sodium methyl silicate solution, sodium silicate solution and water in a ratio of 1:5:9 into the reactor at room temperature, and uniformly mixing; solution D was obtained by slowly adding solution B at a dropping rate of 0.4 mL / min into solution C at a temperature of 85°C, and keeping the reaction for 1 h after the addition was completed. Solution D was replaced with ethylene glycol by distillation, and 10 wt% of 8 nm particle size ethylene glycol solvent silica sol E was prepared by concentration through ultrafiltration.

[0033] S2. Preparation of 2000 ppm polyester functional masterbatch

[0034] A reaction kettle was charged with 14 g of ethylene glycol solvent silica sol E, 500 g of terephthalic acid, 286 g of ethylene glycol, 0.2 g of catalyst, and 0.085 g of stabilizer, and stirred uniformly; the reaction kettle was heated to 240°C, and esterification was carried out for 2.5 h; then all the contents in the reaction kettle were subjected to polycondensation reaction at a temperature of 270°C and a pressure of less than 160 Pa by vacuumizing, for 3 h; after the reaction was completed, the product was collected by cooling, and granulated, to obtain 2000 ppm polyester functional masterbatch with a particle size of 8 nm.

[0035] Example 2

[0036] S1. Preparation of 65 nm ethylene glycol silica sol

[0037] A mixture solution A was prepared by adding sodium silicate solution and water in a ratio of 1:3 in a reaction vessel and stirring uniformly; solution B was obtained by ion exchange of the mixture solution A through a chromatographic column filled with hydrogen type strong acid cation exchange resin; solution C was obtained by adding sodium methyl silicate solution, sodium silicate solution and water in a ratio of 1:3:7 into the reactor at room temperature, and uniformly mixing; solution D was obtained by slowly adding solution B at a dropping rate of 0.8 mL / min into solution C at a temperature of 85°C, and keeping the reaction for 3 h after the addition was completed. Solution D was replaced with ethylene glycol by distillation, and 10 wt% of 65 nm particle size ethylene glycol solvent silica sol E was prepared by concentration through ultrafiltration.

[0038] S2. Preparation of 2000 ppm polyester functional masterbatch

[0039] Put 14g ethylene glycol solvent silica sol E, 500g terephthalic acid, 286g ethylene glycol, 0.2g catalyst, 0.085g stabilizer into the reaction kettle, after stirring uniformly, heated to 240℃, esterification reaction for 2.5h; then all in the reaction kettle at temperature 270℃, under vacuum to less than 160Pa pressure for polycondensation reaction 3h, after the reaction was finished by cooling, cutting, the particle size of 65nm of 2000ppm polyester functional masterbatch was prepared.

[0040] Example 3

[0041] S1. Preparation of 8nm ethylene glycol silica sol

[0042] In the reaction vessel, sodium silicate solution and water were added in proportion of 1:6 and stirred uniformly to obtain a mixed solution A; the mixed solution A was subjected to ion exchange through a chromatographic column filled with hydrogen type strong acid cation exchange resin to obtain solution B; at room temperature, sodium methyl silicate solution, sodium silicate solution and water were added in proportion of 1:5:9 into the reactor, and after mixing uniformly, solution C was obtained; at a temperature of 85℃, solution B was slowly added to solution C at a drop rate of 0.4mL / min, and after the addition was completed, the reaction was maintained for 1-3h to obtain sol D. Sol D was subjected to solvent replacement with ethylene glycol by distillation method, and concentrated by ultrafiltration method to obtain 30wt% of 8nm particle size ethylene glycol solvent silica sol E.

[0043] S2. Preparation of 10000ppm polyester functional masterbatch

[0044] Put 24g ethylene glycol solvent silica sol E, 500g terephthalic acid, 276g ethylene glycol, 0.3g catalyst, 0.090g stabilizer into the reaction kettle, after stirring uniformly, heated to 245℃, esterification reaction for 2h; then all in the reaction kettle at temperature 268℃, under vacuum to less than 160Pa pressure for polycondensation reaction 3h, after the reaction was finished by cooling, cutting, the particle size of 8nm of 10000ppm polyester functional masterbatch was prepared.

[0045] Example 4

[0046] S1. Preparation of 65nm ethylene glycol silica sol

[0047] In a reaction vessel, sodium silicate solution and water were added in a ratio of 1 :3 and stirred uniformly to obtain a mixed solution A; the mixed solution A was subjected to ion exchange through a chromatographic column filled with hydrogen-type strong acid cation exchange resin to obtain solution B; under room temperature conditions, methyl sodium silicate solution, sodium silicate solution and water were added to the reactor in a ratio of 1 :3:7, and after being mixed uniformly, solution C was obtained; at a temperature of 85°C, solution B was slowly added to solution C at a drop rate of 0.8 mL / min, and after the addition was completed, the reaction was maintained for 3 h to obtain sol D. Sol D was subjected to solvent replacement with ethylene glycol by distillation method, and was concentrated by ultrafiltration method to obtain 25 wt% of 65 nm particle size ethylene glycol solvent silica sol E.

[0048] Preparation of 10000 ppm polyester functional masterbatch

[0049] In a reaction vessel, sodium silicate solution and water were added in a ratio of 1 :3 and stirred uniformly to obtain a mixed solution A; the mixed solution A was subjected to ion exchange through a chromatographic column filled with hydrogen-type strong acid cation exchange resin to obtain solution B; under room temperature conditions, methyl sodium silicate solution, sodium silicate solution and water were added to the reactor in a ratio of 1 :3:7, and after being mixed uniformly, solution C was obtained; at a temperature of 85°C, solution B was slowly added to solution C at a drop rate of 0.8 mL / min, and after the addition was completed, the reaction was maintained for 3 h to obtain sol D. Sol D was subjected to solvent replacement with ethylene glycol by distillation method, and was concentrated by ultrafiltration method to obtain 25 wt% of 65 nm particle size ethylene glycol solvent silica sol E.

[0050] Example 5

[0051] Preparation of 50 nm ethylene glycol silica sol

[0052] In a reaction vessel, sodium silicate solution and water were added in a ratio of 1 :3 and stirred uniformly to obtain a mixed solution A; the mixed solution A was subjected to ion exchange through a chromatographic column filled with hydrogen-type strong acid cation exchange resin to obtain solution B; under room temperature conditions, methyl sodium silicate solution, sodium silicate solution and water were added to the reactor in a ratio of 1 :3:7, and after being mixed uniformly, solution C was obtained; at a temperature of 85°C, solution B was slowly added to solution C at a drop rate of 0.8 mL / min, and after the addition was completed, the reaction was maintained for 3 h to obtain sol D. Sol D was subjected to solvent replacement with ethylene glycol by distillation method, and was concentrated by ultrafiltration method to obtain 25 wt% of 65 nm particle size ethylene glycol solvent silica sol E.

[0053] Preparation of 4300 ppm polyester functional masterbatch

[0054] Put 30g ethylene glycol solvent silica sol E, 500g terephthalic acid, 270g ethylene glycol, 0.2g catalyst, 0.08g stabilizer into a reaction kettle, after stirring uniformly, heat to 240℃, esterification reaction for 2 hours; then all in the reaction kettle at temperature 270℃, vacuum to less than 160Pa pressure under the polycondensation reaction 3h, after the reaction is finished by cooling, cutting, the particle size of 50nm 4300ppm polyester functional masterbatch is prepared.

[0055] Comparative example 1

[0056] Put 500g terephthalic acid, 298.5g ethylene glycol, 0.25g catalyst, 0.084g stabilizer trimethyl phosphate into a reaction kettle, after stirring uniformly, heat to 250℃, esterification reaction for 3h; after the esterification reaction is finished, continue to carry out polycondensation reaction for 3h at temperature 270℃, pressure less than 150Pa, after the reaction is finished by cooling, cutting, pure polyester masterbatch is prepared;

[0057] Comparative example 2

[0058] Mix 3g 50nm silica particle powder, 298.5g ethylene glycol, after ultrasonic dispersion, put 500g terephthalic acid, ultrasonic dispersion mixed solution, 0.25g catalyst, 0.085g stabilizer trimethyl phosphate into a reaction kettle A, after stirring uniformly, heat to 240℃, esterification reaction for 3h; then all in the reaction kettle A at temperature 265-290℃, pressure less than 150Pa under the polycondensation reaction 2h, after the reaction is finished by cooling, cutting, 50nm 4300ppm polyester functional masterbatch is prepared;

[0059] Comparative example 3

[0060] Mix 3g 500nm silica particle powder, 298.5g ethylene glycol, after ultrasonic dispersion, put 500g terephthalic acid, ultrasonic dispersion mixed solution, 0.25g catalyst, 0.085g stabilizer trimethyl phosphate into a reaction kettle A, after stirring uniformly, heat to 240℃, esterification reaction for 3h; then all in the reaction kettle A at temperature 265-290℃, pressure less than 150Pa under the polycondensation reaction 2h, after the reaction is finished by cooling, cutting, 500nm 4300ppm polyester functional masterbatch is prepared;

[0061] Comparative example 4

[0062] The polyester functional masterbatch is prepared by a double screw extrusion method. 400 g of pure polyester masterbatch is added into a double screw feeding kettle, 50 nm particle size and 30% solid content of silica functional particle ethylene glycol solvent silica sol is injected at the middle liquid injection position, heated to 260°C, and then melted and extruded under the stirring of the double screw to obtain the 50 nm 75000 ppm polyester functional masterbatch after cooling and granulation.

[0063] The polyester functional masterbatch prepared in the above examples and comparative examples is added into the polyester masterbatch core layer formula of the release film base film at an addition ratio of 500 ppm. The polyester masterbatch is melted and extruded into a sheet, and then high-performance polyester base film is prepared after bidirectional stretching, orientation, heat setting and cooling. The optical properties such as haze and light transmittance and the dispersion of functional particles in the film are tested, and the specific performance comparison is shown in Table 1 below.

[0064] Table 1 Performance comparison of functional masterbatch applied to the preparation of release film base film

[0065] Item Particle diameter (nm) Concentration (ppm) Dispersibility Haze (%) Transmittance (%) Example 1 8 nm 2000 Good 2.5 89.5 Example 2 65 nm 2000 Good 2.8 88.5 Example 3 8 nm 10000 Good 2.6 90.1 Example 4 65 nm 10000 Good 3.0 88.9 Example 5 50 nm 4300 Good 2.8 89.1 Comparative Example 1 / / / 2.5 88.3 Comparative Example 2 50 nm 4300 Poor 4.3 86.2 Comparative Example 3 500 nm 4300 General 5.5 85.9 Comparative Example 4 50 nm 75000 General 3.1 88.3

[0066] As shown in Table 1 above, Comparative Example 1 is a basic control sample without adding functional particles. Since no particles are added, the nucleation center of the masterbatch is less, the crystallinity is low, and the haze and light transmittance are relatively low after stretching into a film. Comparative Example 2 is the in-situ synthesis of the masterbatch using a silica nanoparticle powder dispersion liquid. The dispersion effect of the powder dispersion liquid is poor, the masterbatch can be normally synthesized, but there are problems such as agglomeration during the synthesis process, resulting in high haze and poor light transmittance after stretching into a film. Comparative Example 3 uses a large particle size silica nanoparticle dispersion liquid for in-situ synthesis of the masterbatch. Due to the coexistence of dispersion and large particle size problems, the haze is higher and the light transmittance is lower after stretching into a film. Comparative Example 4 is the preparation of a small particle size functional particle masterbatch by a double screw extrusion method. The double screw method can only prepare high-concentration masterbatch, and the dispersion is relatively poor in the application of stretching into a film, so the haze and light transmittance performance are relatively poor compared with the in-situ synthesis method.

[0067] In summary, the particle size and concentration of the functional particles in the polyester functional masterbatch of the present application are accurately controllable, and the polyester functional masterbatch can be prepared according to different needs. The main difference between different embodiments of the present application is that the particle size and particle concentration of the prepared particles are different, and the specific application can be selected according to the specific use environment. For example, if high light transmittance is required, the polyester functional masterbatch product in Example 1 can be selected. Small particle size silica functional particles can effectively improve the number of nucleation centers in the masterbatch, and have a significant effect on the crystallinity during polyester stretching, which can affect the optical properties and other properties. In addition, small particle size silica functional particles have small particle size and low surface roughness, and can be widely used in the production of polarizing plate release film base film and sheet-type multilayer ceramic capacitor release film base film which have high requirements for surface roughness.

[0068] The foregoing description of the embodiments has been presented for the purpose of illustration and description. It is not intended to be exhaustive or to limit the application to the precise form disclosed. Modifications and variations are possible in light of the above teachings or can be acquired from practice of the application. As well, the description is presented in the context of the preferred embodiments as of their onset and might not represent the scope of the application, and the language sent forth by the claims should be understood to be interpreted in the context of the specification as a whole.

Claims

1. A method for preparing a polyester functional masterbatch, characterized in that: The preparation method includes the following steps: S1. Preparation of small-particle-size silica sol: Sodium silicate solution and water were added to a reaction vessel in a ratio of 1:(3~6) and stirred until homogeneous to obtain mixed solution A. Mixed solution A was then passed through a chromatographic column packed with hydrogen-form strong acid cation exchange resin for ion exchange to obtain solution B. At room temperature, sodium methyl silicate solution, sodium silicate solution and water were added to a reactor in a ratio of 1:(3~5):(7~9) and mixed until homogeneous to obtain solution C. Solution B was then slowly added dropwise to solution C at a temperature of 75 ℃~90 ℃. After the addition was completed, the reaction was maintained at this temperature for 1~3 h to obtain sol D. S2. Preparation of ethylene glycol silica sol: The sol D obtained in step S1 is distilled to replace the solvent with ethylene glycol, and then concentrated by ultrafiltration to obtain 10~30wt% ethylene glycol solvent silica sol E. S3. Preparation of polyester functional masterbatch: 10-30 parts by weight of ethylene glycol solvent silica sol E, 500 parts by weight of terephthalic acid, 270-290 parts by weight of ethylene glycol, 0.2-0.3 parts by weight of catalyst, and 0.08-0.09 parts by weight of stabilizer are added to a reactor and stirred evenly. The mixture is then heated to 230-265°C for esterification reaction for 2-4 hours. All materials in the reactor are then subjected to polycondensation reaction at 265-285°C under vacuum to a pressure less than 160 Pa for 2-5 hours. After the reaction is completed, the mixture is cooled, collected, and pelletized to obtain polyester functional masterbatch. In step S1, the dropping rate of solution B is 0.4~0.8 mL / min; The polyester functional masterbatch is prepared by direct esterification polycondensation of ethylene glycol silica sol, ethylene glycol and terephthalic acid; the particle size of the silica functional particles in the polyester functional masterbatch is 8 nm to 65 nm; the content of silica functional particles in the polyester functional masterbatch is 2000 ppm to 10000 ppm.

2. The method for preparing polyester functional masterbatch according to claim 1, characterized in that: The polyester masterbatch has an intrinsic viscosity of 0.66±0.05 dL / g, a terminal carboxyl group content of ≤24.0±3.0 mol / t, and a diethylene glycol content of 1.0±0.15 wt%.

3. The method for preparing polyester functional masterbatch according to claim 1, characterized in that: In step S3, the catalyst is one or a combination of two or more of antimony trioxide, antimony glycolate, or antimony acetate.

4. The method for preparing polyester functional masterbatch according to claim 1, characterized in that: The stabilizer in step S3 is either trimethyl phosphate or triphenyl phosphate.