Polyester composition, preparation method and application thereof, and optical reflective film

Abstract

The present application relates to the field of polyester composition, discloses a kind of polyester composition and its preparation method and application.The polyester composition includes polyester, maleic anhydride copolymer microsphere and adjuvant;With the amount of the polyester 100 parts, the amount of the maleic anhydride copolymer microsphere is 10-60 parts, and the amount of the adjuvant is 0.1-15 parts;The average particle size of the maleic anhydride copolymer microsphere is 500-1600nm.The composition contains the maleic anhydride copolymer microsphere with uniform particle size distribution, which can be well dispersed in the polyester matrix without using dispersant, compatibilizer, without agglomeration phenomenon, can avoid the size and its distribution of inorganic particles are not uniform, poor dispersibility, poor compatibility and other shortcomings.The composition is applied to optical reflection film, which can simplify process flow and improve the light reflectivity of film product.

Description

Technical Field

[0001] The present invention relates to the field of polyester compositions, in particular to a polyester composition, a preparation method and application thereof, and an optical reflective film. Background Art

[0002] Liquid crystal display technology has been widely adopted and has become a vital component of the optoelectronic information industry. An LCD is a passive display device that does not emit light itself. The images and text it displays are the result of its modulation of the light emitted by a backlight source. Therefore, key display indicators such as brightness, chromaticity, and power consumption depend on the performance of the backlight source. The main components of an LCD backlight module are: light source, reflective film, light guide plate, diffuser film, brightness enhancement film, and outer frame. The reflective film is located at the very bottom of the backlight module, beneath the light guide plate. Its function is to reflect light that leaks through the light guide plate back to the panel, thereby reducing light loss and increasing backlight brightness.

[0003] Main types of reflective films include polypropylene (PP), polycarbonate (PC), and polyethylene terephthalate (PET). Compared to PP and PC, PET reflective films offer superior heat resistance, ductility, mechanical properties, weather resistance, fatigue resistance, electrical insulation, and chemical resistance. Currently, the main methods for preparing reflective films domestically and internationally include coating, multilayer film, blending, and microporous methods. The blending method involves directly adding reflective particles (such as calcium carbonate, magnesium sulfate, titanium dioxide, silicon dioxide, zinc oxide, and other inorganic particles) to a film, which is then melt-extruded and cast using an extruder. The microporous method involves adding components (inorganic particles) incompatible with the matrix resin to the film. The film is then processed through melt extrusion, cast film, and then subjected to longitudinal and transverse stretching and heat setting steps to create pores in the film, resulting in a whitening effect and increased reflectivity. A large number of micron-sized holes are introduced in the middle of the film. There is air in the micron-sized holes. When light enters the film and encounters the micron-sized holes, it will be reflected or refracted, and some will undergo total reflection. A large number of micron-sized holes can cause the light to be reflected multiple times, thereby increasing the reflectivity of the film.

[0004] CN100480305C discloses a white polyester film obtained from a composition formed by copolyester and inorganic particles, wherein the proportion of inorganic particles in the composition is 30 to 50 wt%. The transverse and longitudinal heat shrinkage rates of the above film at 85°C are ≤0.7%, and the transverse and longitudinal heat shrinkage rates at 150°C are ≤5.0%.

[0005] CN102686653B discloses a light reflective film prepared by using PET as a matrix resin, adding TOPAS cycloolefin polymer incompatible with PET and inorganic particles TiO2 to blend into a film, and stretching to form pores.

[0006] CN102362217B discloses a reflective film for liquid crystal display device backlight unit, which comprises a light reflection layer and a support layer, wherein the light reflection layer is a film with a pore volume rate of 55-80% obtained by stretching a cast sheet of a combination of PET and barium sulfate, and the support layer is a biaxially stretched polyester film.

[0007] CN103030937B discloses a single-layer biaxially stretched light reflection polyester film prepared by blending a polyester base material with inorganic particles (such as titanium dioxide, silicon dioxide or barium sulfate) and resin (such as polyvinylidene fluoride or polydimethylsiloxane), a compatibilizer, an ultraviolet absorber and an antistatic agent, and then stretching.

[0008] The above method has the problems of uneven distribution of inorganic particles, affecting the reflectivity of the film, easy film rupture, difficulty in film preparation, large film weight and poor mechanical properties of the film. To improve the above problems, additional dispersants, coupling agents, compatibilizers or copolyester as the base material are usually introduced, which increases the complexity of the process, and the high thermal shrinkage rate of the copolyester leads to poor thermal dimensional stability of the film. SUMMARY

[0009] In order to overcome the problems in the prior art, the present application provides a polyester composition, a preparation method and application thereof, and an optical reflection film. The composition contains maleic anhydride copolymer microspheres with uniform particle size distribution, which can be well dispersed in the polyester matrix without using dispersants and compatibilizers, and can avoid the problems of uneven size and distribution of inorganic particles, poor dispersibility and poor compatibility. The composition applied to the optical reflection film can simplify the process flow and improve the reflectivity of the film product.

[0010] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a polyester composition, characterized in that the polyester composition comprises polyester, maleic anhydride copolymer microspheres and an auxiliary agent.

[0011] The amount of the maleic anhydride copolymer microspheres is 10-60 parts, and the amount of the auxiliary agent is 0.1-15 parts, based on 100 parts of the polyester.

[0012] The average particle size of the maleic anhydride copolymer microspheres is 500-1600 nm.

[0013] The second aspect of the present application provides the application of the above-mentioned polyester composition in an optical reflection film.

[0014] The third aspect of the present application provides a preparation method of the above-mentioned polyester composition, characterized in that the method comprises:

[0015] (1) mixing the polyester, the maleic anhydride copolymer microspheres and the antioxidant complexing agent to obtain a mixture;

[0016] (2) melt blending extruding the mixture in a twin-screw extruder, pelletizing, drying to obtain the polyester composition.

[0017] The fourth aspect of the present application provides an optical reflection film, characterized in that the optical reflection film is prepared from the polyester composition.

[0018] The polyester composition and the preparation method and application thereof provided by the above technical solution have the following beneficial effects:

[0019] The polyester composition provided by the present application contains maleic anhydride copolymer microspheres, which can realize uniform dispersion of the maleic anhydride copolymer microspheres and other components in the polyester resin matrix without using dispersants and compatibilizers, and the pore size of the micropores of the film prepared from the composition is uniform; the problems such as small adjustable range of physical properties and reflectivity of the reflection film, complex process and the like in the prior art can be solved, the adaptability is wide, the operation is simple, and the product performance is stable. The polyester composition prepared by the present application can be widely applied to the field of optical reflection films. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is an SEM photo of the cross section of the polyester composition sample prepared in Example 1;

[0021] Figure 2 is an SEM photo of the cross section of the polyester composition sample prepared in Comparative Example 2;

[0022] Figure 3 is an SEM photo of the cross section of the polyester composition sample prepared in Comparative Example 3. DETAILED DESCRIPTION

[0023] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values are understood to be approximate values. The exact numerical values of the endpoints of the ranges and the separate points are not to be construed as being precise values, and they are understood to be used in a merely illustrative sense. Within the scope of this disclosure, any value can be used as a precise value for the endpoints of the ranges and the separate points.

[0024] The first aspect of the present application provides a polyester composition, characterized in that the polyester composition comprises polyester, maleic anhydride copolymer microspheres and an additive;

[0025] The amount of the maleic anhydride copolymer microspheres is 10-60 parts, and the amount of the additive is 0.1-15 parts, based on 100 parts of the polyester;

[0026] The average particle size of the maleic anhydride copolymer microspheres is 500-1600 nm.

[0027] The polyester composition provided by the application contains maleic anhydride copolymer microspheres, and can realize uniform dispersion of the maleic anhydride copolymer microspheres and other components in a polyester resin matrix without using dispersants and compatibilizers, and the pore size of micropores of a film prepared from the composition is uniform; the problems in the prior art such as small adjustable range of physical properties and reflectivity of a reflective film, complex process, wide adaptability, simple operation, and stable product performance can be solved. The polyester composition prepared by the application can be widely applied in the field of optical reflective films.

[0028] Further, the amount of the maleic anhydride copolymer microspheres is 12-50 parts, and the amount of the auxiliary agent is 0.3-12 parts, based on 100 parts of the polyester.

[0029] Further, the average particle size of the maleic anhydride copolymer microspheres is 600-1300 nm.

[0030] According to the application, the melting enthalpy of the polyester is △H mPET , and the melting enthalpy of the polyester composition is △H m组合物 .

[0031] The difference between △H mPET and △H m组合物 is 6-28 J / g.

[0032] In the application, when the difference between the melting enthalpy of the polyester and the melting enthalpy of the polyester composition meets the above range, the maleic anhydride copolymer microspheres in the polyester composition are uniformly distributed and can produce a good light reflection effect, and there is no phenomenon of a large decrease in the melting enthalpy caused by agglomeration of the maleic anhydride copolymer microspheres, so that the light reflection film prepared from the composition has excellent physical properties and reflectivity.

[0033] In the application, the melting enthalpy of the polyester and the polyester composition is measured by differential scanning calorimetry.

[0034] Further, the difference between △H mPET and △H m组合物 is 8-25 J / g.

[0035] According to the application, the copolymer in the maleic anhydride copolymer microspheres contains structural unit A from maleic anhydride and structural unit B from a comonomer, the molar content of the structural unit A is 48-55%, and the molar content of the structural unit B is 45-52%, based on the total molar amount of each structural unit in the copolymer.

[0036] Further, the mole content of the structural unit A is 49-51%, and the mole content of the structural unit B is 49-51%, based on the total mole amount of each structural unit in the copolymer.

[0037] According to the present application, the comonomer is selected from at least one of styrene, α-methylstyrene, vinyl acetate, carbon tetra-olefins and carbon penta-olefins.

[0038] In the present application, the mixed carbon four refers to a general term of hydrocarbon compounds with four carbon atoms (mainly including butene), and generally, in addition to butene with different structures (such as trans-2-butene, cis-2-butene, n-butene, iso-butene), the carbon four also includes a certain amount of alkanes (such as n-butane) and other possible impurities. In the present application, the content of olefins in the mixed carbon four is within the range of 60-75% by weight.

[0039] In the present application, the mixed carbon five refers to a general term of hydrocarbon compounds with five carbon atoms (mainly including pentene), and generally, in addition to pentene with different structures (such as dienes (isoprene, cyclopentadiene, 1,4-pentadiene, and piperonyl) and mono-olefins (1-pentene, 2-pentene, cyclopentene, 2-methyl-1-butene, 2-methyl-2-butene)), the carbon five also includes a certain amount of alkanes (such as n-pentane, iso-pentane, cyclopentane, 2-methylbutane), acetylenes (such as butyne-2, 3-pentene-1-yne) and other possible impurities. In the present application, the content of olefins in the mixed carbon five is within the range of 55-65% by weight.

[0040] In one specific embodiment of the present application, the maleic anhydride copolymer microspheres are prepared according to the following steps:

[0041] (1) dissolving maleic anhydride, comonomer and initiator in a reaction medium to form a homogeneous solution in an inert atmosphere;

[0042] (2) after the homogeneous solution is subjected to a polymerization reaction to obtain a copolymer emulsion suspension, the copolymer emulsion suspension is subjected to solid-liquid separation to obtain the pore-forming agent;

[0043] wherein, based on the total weight of maleic anhydride and comonomer, the amount of maleic anhydride is 50-90wt%, and the amount of comonomer is 10-50wt%;

[0044] The reaction medium is a mixture of the compound shown in formula (1) and alkanes;

[0045]

[0046] wherein, R1 and R2 are each independently an alkyl group with 1 to 6 carbon atoms.

[0047] In one embodiment of the present application, the comonomer is selected from at least one of styrene, α-methylstyrene and vinyl acetate.

[0048] In the present application, maleic anhydride monomers and comonomers are copolymerized in a specific ratio to obtain a maleic anhydride copolymer in the form of microspheres with excellent uniformity, and the copolymer has a clean surface and good dispersibility in a medium without aggregation.

[0049] Further, in order to obtain a maleic anhydride copolymer microsphere with uniform particles and excellent morphology, the inventors have studied the amount of maleic anhydride and comonomer used in the polymerization process, and the results show that when the amount of maleic anhydride is 50-60 wt% and the amount of comonomer is 40-50 wt% based on the total weight of the polymerization monomers, the obtained maleic anhydride copolymer microspheres have uniform particles, excellent particle morphology, and a clean particle surface, and the comprehensive performance of the copolymer microspheres is more excellent.

[0050] According to the present application, the total mass concentration of maleic anhydride and comonomer is 5-25 wt%, preferably 5-20 wt%, based on the total weight of the homogeneous solution.

[0051] According to the present application, the initiator is an organic peroxide and / or an azo compound.

[0052] According to the present application, the organic peroxide is selected from at least one of dibenzoyl peroxide, dicumyl peroxide, ditert-butyl peroxide, dilauryl peroxide, tert-butyl peroxybenzoate, diisopropyl peroxydicarbonate and dicyclohexyl peroxydicarbonate.

[0053] According to the present application, the azo compound is selected from azobisisobutyronitrile and / or azobisisoheptyl nitrile.

[0054] According to the present application, the mass concentration of the initiator is 0.01-5 wt%, preferably 1-4 wt%, based on the total weight of the homogeneous solution.

[0055] According to the present application, in formula (1), R1 and R2 are each independently an alkyl group with 1 to 4 carbon atoms, more preferably methyl or ethyl.

[0056] According to the present application, the alkane is an alkane with 6 to 12 carbon atoms.

[0057] In the present invention, a mixture of the compound represented by formula (1) and an alkane is selected as the reaction medium. The mixture can cooperate with the specific amount of maleic anhydride and the comonomer described in the present invention to achieve a self-stabilizing precipitation polymerization reaction of the maleic anhydride and the comonomer. The polymerization reaction system does not require the addition of any stabilizer or co-stabilizer, has a self-stabilizing dispersion effect, and the surface of the obtained polymer microspheres is clean and pollution-free.

[0058] Furthermore, the alkane is at least one selected from hexane, heptane and octane, more preferably hexane.

[0059] According to the present invention, the amount of the alkane used is 50-90 vol%, preferably 60-80 vol%, based on the total volume of the reaction medium.

[0060] In the present invention, the polymerization reaction is carried out in an inert atmosphere, which can be provided by conventional inert gases in the prior art, such as nitrogen.

[0061] According to the present invention, the polymerization reaction conditions include: polymerization temperature of 61-100° C., preferably 70-90° C.; polymerization time of 1-24 h, preferably 2-12 h.

[0062] In the present invention, a water bath and / or an oil bath is used to provide the heat required for the polymerization of the present invention.

[0063] In the present invention, the solid-liquid separation may be a conventional solid-liquid separation method in the art, such as centrifugal separation.

[0064] In the present invention, when centrifugal separation is adopted, the centrifugal speed is 1500-5000 rad / min and the centrifugal time is 5-60 min.

[0065] In one embodiment of the present invention, the maleic anhydride copolymer microspheres are prepared according to the following steps:

[0066] In the presence of an inert atmosphere, an initiator and an organic solvent, maleic anhydride and a comonomer are copolymerized to obtain the maleic anhydride copolymer microspheres;

[0067] The comonomer is selected from mixed C4 and / or mixed C5.

[0068] In the present invention, the copolymerization reaction may be a one-step reaction using a precipitation polymerization method.

[0069] According to the present invention, the weight ratio of the maleic anhydride to the comonomer is 1:(0.2-3); preferably 1:(0.8-3).

[0070] According to the present invention, based on the total amount of maleic anhydride, the amount of the initiator is 0.05-20 mol%.

[0071] According to the present invention, the organic solvent is selected from at least one of isoamyl acetate, butyl acetate, isopropyl acetate and ethyl acetate. Preferably, the concentration of maleic anhydride is 5-25 wt %, preferably 10-20 wt %, based on the total weight of the organic solvent.

[0072] According to the present invention, the copolymerization reaction conditions are: copolymerization reaction temperature is 50-100° C., preferably 70-90° C.; copolymerization reaction pressure is 0.2-2 MPa, preferably 0.5-1 MPa; copolymerization reaction time is 5-10 h, preferably 6-9 h.

[0073] According to the present invention, the initiator is an organic peroxide and / or an azo compound.

[0074] According to the present invention, the organic peroxide is at least one selected from dibenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, dodecyl peroxide, tert-butyl perbenzoate, diisopropyl peroxydicarbonate and dicyclohexyl peroxydicarbonate.

[0075] According to the present invention, the azo compound is selected from azobisisobutyronitrile and / or azobisisoheptanenitrile.

[0076] In the present invention, a water bath and / or an oil bath is used to provide the heat required for the polymerization of the present invention.

[0077] In the present invention, the solid-liquid separation may be a conventional solid-liquid separation method in the art, such as centrifugal separation or flash separation.

[0078] In the present invention, when centrifugal separation is adopted, the centrifugal speed is 1500-5000 rad / min and the centrifugal time is 5-60 min.

[0079] In the present invention, when flash separation is adopted, it can be carried out in a flash separator, with a flash temperature of 10-40° C. and a flash pressure of 0 MPa.

[0080] According to the present invention, the polyester is selected from at least one of polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and polyethylene naphthalate (PEN), preferably polyethylene terephthalate (PET).

[0081] In the present invention, at 25°C, the intrinsic viscosity of the polyester is 0.62-0.88 dL / g; the glass transition temperature of the polyester is 65-85°C; the melting point of the polyester is 240-265°C; and the crystallization temperature of the polyester is 168-192°C.

[0082] In a specific embodiment of the present invention, the polyester composition further comprises at least one organic particle selected from linear, branched or cyclic polyolefin resins such as polyethylene, polypropylene, polybutene, polymethylpentene, cyclopentadiene, acrylic resins such as poly(meth)acrylate, polystyrene, fluororesins and silicone resins.

[0083] Preferably, the polyester composition further comprises at least one organic particle selected from polyethylene, polystyrene, polypropylene, polybutene, poly-4-methyl-1-pentene, cyclic olefin copolymers, polymethacrylic acid, silicone resin, ethylene-methyl methacrylate copolymer, and ethylene-vinyl acetate copolymer, preferably polypropylene, poly-4-methyl-1-pentene, and cyclic olefin copolymer. The amount of the organic particles used is not particularly limited. For example, the amount of the organic particles is 10-20 parts per 100 parts of the polyester.

[0084] According to the present invention, the auxiliary agent includes at least one of an antioxidant, a heat stabilizer, an antistatic agent, an anti-hydrolysis agent, a nucleating agent, a flame retardant and an ultraviolet absorber.

[0085] According to the present invention, the antioxidant is selected from at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris(2,4-di-tert-butyl)phenyl phosphite, octadecyl propionate and alkylated polyphenols.

[0086] Furthermore, the antioxidant is pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (Antioxidant 1010) and (2,4-di-tert-butylphenyl)trisphosphite; or, n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Antioxidant 1076) and (2,4-di-tert-butylphenyl)trisphosphite. Specifically, the weight ratio of pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate to (2,4-di-tert-butylphenyl)trisphosphite is 1-3:1, preferably 2-3:1.

[0087] According to the present invention, the heat stabilizer is a phosphorus-based heat stabilizer, preferably at least one selected from trimethyl phosphate, triphenyl phosphate and triethyl phosphate.

[0088] According to the present invention, the antistatic agent is at least one selected from ethoxylated alkylamines, tetraalkylammonium salts, alkylbenzene sulfonates, alkyl sulfonates, polyetheresteramides, polyetheramideimides, and copolymers of methoxypolyethylene glycol and methacrylate.

[0089] According to the present invention, the anti-hydrolysis agent is selected from carbodiimides, preferably at least one selected from dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide and polycarbodiimide.

[0090] According to the present invention, the nucleating agent is selected from at least one of an inorganic salt nucleating agent, an organic acid salt nucleating agent, an ionomer nucleating agent, and an alkali metal salt nucleating agent of a polyester oligomer. In the present invention, the inorganic salt nucleating agent is selected from at least one of a carbonate nucleating agent, a silicate nucleating agent, and a sulfate nucleating agent; and the organic acid salt nucleating agent is selected from at least one of a monocarboxylate nucleating agent, a benzoate nucleating agent, an aromatic hydroxysulfonic acid metal salt nucleating agent, and an organophosphorus compound nucleating agent.

[0091] According to the present invention, the flame retardant is selected from brominated organic flame retardants and / or inorganic flame retardants. In the present invention, the inorganic flame retardant is selected from at least one of aluminum hydroxide, magnesium hydroxide, zinc borate and molybdenum ditelluride.

[0092] According to the present invention, the ultraviolet absorber is selected from at least one of methyl o-hydroxybenzoate, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2,4-dihydroxybenzophenone and 2-hydroxy-4-n-octyloxybenzophenone.

[0093] In the present invention, the amounts of the antioxidant, the heat stabilizer, the antistatic agent, the anti-hydrolysis agent, the nucleating agent, the flame retardant and the ultraviolet absorber may be conventional amounts in the art.

[0094] According to the present invention, the polyester composition does not contain a dispersant, a compatibilizer and a coupling agent.

[0095] A second aspect of the present invention provides use of the polyester composition in an optical reflective film.

[0096] A third aspect of the present invention provides a method for preparing the above-mentioned polyester composition, characterized in that the method comprises:

[0097] (1) mixing polyester, maleic anhydride copolymer microspheres and an auxiliary agent to obtain a mixture;

[0098] (2) The mixture is melt-blended and extruded in a twin-screw extruder, pelletized, and dried to obtain the polyester composition.

[0099] According to the present invention, the rotation speed of the twin-screw extruder is 80-300 r / min.

[0100] Preferably, the temperatures of the feeding section, melting section, homogenizing section and die head of the twin-screw extruder are 200-230°C, 240-260°C, 255-275°C and 250-270°C respectively.

[0101] A fourth aspect of the present invention provides an optical reflective film, characterized in that the optical reflective film is made from the above-mentioned polyester composition.

[0102] In the present invention, the optical reflective film prepared from the polyester composition not only retains the excellent physical properties of the polyester composition, but more importantly, has a high light reflectivity and can be widely used in the field of light reflective films.

[0103] In the present invention, there is no particular limitation on the preparation method of the optical reflective film and the film can be prepared according to conventional methods in the art. For example, the polyester composition is melted at 275°C using a single-screw extruder with an aspect ratio greater than 40, extruded through a single-layer T-shaped die to form a single-layer thick sheet, and then cooled to 30-60°C by rollers passing cold water at 20°C to form a polyester cast sheet. The cast sheet is preheated at 80-180°C and then uniaxially stretched by 2-5 times to form a polyester film. The polyester film then enters a heat setting zone in an electric heating channel at a heat setting temperature of 100-200°C. After passing through the heat setting zone, the polyester film is cooled at 60-80°C to form a light-reflective polyester film with an average thickness of 0.1-0.3 mm.

[0104] The present invention will be described in detail below through examples. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0105] The relevant data in the present invention and its embodiments were obtained by the following test methods:

[0106] 1. The content of each structural unit in maleic anhydride copolymer microspheres is 1 H NMR was tested by 1 The content of each structural unit was calculated from the ratio of the peak area corresponding to the characteristic hydrogen in the corresponding structural unit in H NMR;

[0107] 2. Polymerization yield of maleic anhydride copolymer (Cp): Cp = Mp × 100% / Mm

[0108] Wherein, Mp is the mass of the obtained polymer; Mm is the total mass of the added monomers;

[0109] 3. Copolymer microsphere particle size test method: After the copolymer microsphere powder is vacuum-sprayed with gold, the morphology is observed on a Hitachi S4800 field emission scanning electron microscope. 500 microspheres are selected from the electron microscope photographs, and their diameters are measured. The average particle size of the microspheres is calculated using the mathematical averaging method.

[0110] 4. Conversion efficiency of mixed C4: Weigh the polymer after the reaction, conversion efficiency (%) = [(4 × actual mass of the obtained polymer) / (11 × actual mass of C4 used)] × 100%;

[0111] 5. Intrinsic Viscosity: Place approximately 10g of sample in liquid nitrogen and cool for 10 minutes. Remove the sample and immediately crush it using a pulverizer for no more than 30 seconds. Grind the entire sample to a particle size of less than 1mm. Determine the intrinsic viscosity using an Ubbelohde viscometer using the method and solvent specified in GB / T 14190-2017.

[0112] 6. Cross-sectional morphology of polyester composite samples and dispersion of incompatible components: The samples were immersed in liquid nitrogen for 15 minutes and then fractured. The cross-sections were then gold-sprayed and characterized using a Hitachi S4800 field emission scanning electron microscope to obtain microscopic morphology photographs.

[0113] 7. T C , Tm and △Hm: Differential scanning calorimetry was used to analyze the melting and crystallization processes of the material. The specific operation was as follows: Under nitrogen protection, 5-10 mg of sample was measured from 20℃ to 300℃ using a three-stage temperature ramp measurement method. The change in heat flow reflects the melting and crystallization process of the material. The crystallization temperature T was calculated according to GB / T 19466.3-2004. C , melting temperature Tm and melting enthalpy △Hm;

[0114] 8. Tensile properties: measured according to the method specified in GB / T 1040.3-2006 using the INSTRON universal tensile testing machine produced by Instron Corporation of the United States.

[0115] 9. Reflectivity: Reflectivity was measured using a HunterLab ColorQuestXE spectrometer (USA) under a D65 illuminant using an integrating sphere with a d / 8° configuration, in accordance with the method specified in GB / T 3979-2008. Reflectivity data is a weighted average of reflectivity at 10nm wavelength intervals from 400-700nm, with the weights corresponding to the energy distribution curve of the D65 illuminant.

[0116] Polyester: PET-1, intrinsic viscosity 0.66 dL / g, glass transition temperature 79.1°C, crystallization temperature 188.9°C, melting point 259.1°C, purchased from Sinopec Yizheng Chemical Fiber Co., Ltd.

[0117] Polyester: PET-2, intrinsic viscosity 0.84 dL / g, glass transition temperature 68.2°C, crystallization temperature 171.5°C, melting point 255.1°C, purchased from China Resources Chemical Materials Technology Co., Ltd.

[0118] Polyester: PET-3, intrinsic viscosity 0.76 dL / g, glass transition temperature 74.4°C, crystallization temperature 178.5°C, melting point 257.3°C, purchased from Zhejiang Hengyi High-tech Materials Co., Ltd.

[0119] Other raw materials used in the examples and comparative examples are all commercially available.

[0120] Preparation Example 1

[0121] Preparation of Maleic Anhydride Copolymer Microspheres A1

[0122] 322.5g of maleic anhydride, 57.5g of azobisisobutyronitrile, 302.5g of styrene, 1.36L of acetone, and 4.68L of hexane (77.5 vol%) were added to a 20L reactor. After uniform mixing, nitrogen was passed through for 20 minutes, and the reactor temperature was raised to 70°C for 6 hours. After the reaction was completed, the resulting polymer emulsion suspension was centrifuged at 2000 rad / min for 20 minutes to obtain 556g of maleic anhydride styrene copolymer microspheres A1, corresponding to a polymerization yield of 89%. The amount of maleic anhydride in the monomers was 51.6wt%, and the amount of styrene was 48.4wt%. In the homogeneous solution, the mass concentration of maleic anhydride and comonomer was 12.9wt%, and the mass concentration of initiator was 1.19wt%.

[0123] The polymer microspheres 1 H NMR measurement showed that, based on the total molar amount of each structural unit in the polymer, the molar content of the structural unit A derived from maleic anhydride was 49%, and the molar content of the structural unit B derived from styrene was 51%.

[0124] The average particle size of the maleic anhydride copolymer microspheres A1 is about 1000 nm.

[0125] Preparation Example 2

[0126] Preparation of Maleic Anhydride Copolymer Microspheres A2

[0127] The mass percentages of the components in the mixed C4 are as follows: 1,3-butadiene, 0.06%; trans-2-butene, 12.67%; isobutane, 37.09%; isobutylene, 19.48%; cis-2-butene, 27.79%; 1-butene, 1.02%; and others, 1.89%. 13.8 kg of the mixed C4 was introduced into a 200 L reactor containing an organic reaction solution of 10 kg of maleic anhydride, 4.05 kg of dibenzoyl peroxide, and 100 L of isoamyl acetate for free radical copolymerization. The reaction pressure was 1 MPa, the reaction temperature was 80°C, and the reaction time was 6 hours. The weight ratio of maleic anhydride to the mixed C4 was 1:1.38. The concentration of maleic anhydride in the organic solvent was 10.2 wt%.

[0128] The copolymerization product was passed into a flash separator for gas-liquid separation at 30°C and 0 MPa. The resulting liquid-solid mixture was further centrifuged in a centrifuge at 4000 rad / min for 20 minutes to obtain a solid product. The liquid was returned to the reactor. The solid product was then washed with hexane and filtered through a sand core funnel to obtain a filter cake that was vacuum dried at 90°C for 8 hours to yield 20.55 kg of maleic anhydride-mixed C4 copolymer A2.

[0129] Maleic anhydride-mixed C4 copolymer A2 1 H NMR analysis showed that, based on the total molar amount of each structural unit in the polymer, the molar content of structural unit A derived from maleic anhydride was 50 mol%; the molar content of structural unit B derived from mixed C4 was 50 mol%. The conversion efficiency of mixed C4 calculated by weight method was 54 wt%.

[0130] The average particle size of the maleic anhydride-mixed C4 copolymer microspheres is about 1200 nm.

[0131] Preparation Example 3

[0132] Preparation of Maleic Anhydride Copolymer Microspheres A3

[0133] 405.5g of maleic anhydride, 50.5g of azobisisobutyronitrile, 273.1g of styrene, 1.185L of acetone, and 4.68L of hexane (79.8vol%) were added to a 20L reactor. After uniform mixing, nitrogen was passed through for 20 minutes, and the reactor temperature was raised to 70°C for 8 hours. After the reaction was completed, the resulting polymer emulsion suspension was centrifuged in a centrifuge at a speed of 2000rad / min for 20 minutes to obtain 529g of maleic anhydride styrene copolymer microspheres A3, corresponding to a polymerization yield of 78%. In the polymerization monomers, the amount of maleic anhydride was 59.8wt%, and the amount of styrene was 40.2wt%. In the homogeneous solution, the mass concentration of maleic anhydride and comonomer was 14.3wt%, and the mass concentration of initiator was 1.06wt%.

[0134] The polymer microspheres 1 H NMR measurement showed that, based on the total molar amount of each structural unit in the polymer, the molar content of the structural unit A derived from maleic anhydride was 49%, and the molar content of the structural unit B derived from styrene was 51%.

[0135] The average particle size of the maleic anhydride copolymer microspheres A3 is about 1200 nm.

[0136] Preparation Example 4

[0137] Preparation of Maleic Anhydride Copolymer Microspheres A4

[0138] 300.5g of maleic anhydride, 57.5g of azobisisobutyronitrile, 285.5g of styrene, 1.515L of acetone and 4.68L of hexane (the amount of hexane is 75.5vol%) are added to a 20L reactor. After the materials are evenly mixed, nitrogen is passed through for 20min, and the reactor temperature is raised to 70°C for 5h. After the reaction is completed, the polymer emulsion suspension obtained is centrifuged in a centrifuge at a speed of 2000rad / min for 20min to obtain 510g of maleic anhydride copolymer microspheres A4, with a corresponding polymerization yield of 87%. In the polymerization monomer, the amount of maleic anhydride is 51.3wt%, and the amount of styrene is 48.7wt%. In the homogeneous solution, the mass concentration of maleic anhydride and comonomer is 11.9wt%, and the mass concentration of initiator is 1.17wt%.

[0139] The polymer microspheres 1 H NMR measurement showed that, based on the total molar amount of each structural unit in the polymer, the molar content of structural unit A derived from maleic anhydride was 50%, and the molar content of structural unit B derived from styrene was 50%.

[0140] The average particle size of the maleic anhydride copolymer microspheres A4 is about 700 nm.

[0141] Preparation Example 5

[0142] Preparation of Maleic Anhydride Copolymer Microspheres A5

[0143] 151.2g of maleic anhydride, 57.5g of azobisisobutyronitrile, 168.5g of styrene, 2.285L of acetone, and 2.915L of hexane (56.1vol%) were added to a 20L reactor. After uniform mixing, nitrogen was passed through for 20min, and the reactor temperature was raised to 70°C for 4h. After the reaction was completed, the resulting polymer emulsion suspension was centrifuged at 2000rad / min for 20min to obtain 237g of maleic anhydride copolymer microspheres A5, corresponding to a polymer yield of 74%. The amount of maleic anhydride in the monomers was 47.3wt%, and the amount of styrene was 52.7wt%. In the homogeneous solution, the mass concentration of maleic anhydride and comonomer was 7.8wt%, and the mass concentration of initiator was 1.40wt%.

[0144] The polymer microspheres 1 H NMR measurement showed that, based on the total molar amount of each structural unit in the polymer, the molar content of structural unit A derived from maleic anhydride was 47%, and the molar content of structural unit B derived from styrene was 53%.

[0145] The average particle size of maleic anhydride copolymer microspheres A5 is about 450 nm.

[0146] Example 1

[0147] Preparation of polyester compositions

[0148] 100 parts of PET-1 were dried at 140°C for 5 hours and blended with 30 parts of maleic anhydride copolymer microspheres A1, 0.75 parts of antioxidant, and 0.1 parts of heat stabilizer triphenyl phosphate in a high-speed blender. The antioxidants used were pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Antioxidant 1010) and (2,4-di-tert-butylphenyl)trisphosphite, and the weight ratio of the two was 1:1.

[0149] The homogenized pellets were added to a twin-screw extruder for pelletization. The feed, melting, homogenizing, and die temperatures of the twin-screw extruder were set at 220°C, 240°C, 265°C, and 260°C, respectively, and the screw speed was 150 rpm. The polyester composition of the present invention was pelletized. The polyester composition was dried at 140°C for 12 hours and then tested for its properties. The performance results are shown in Table 1. The polyester composition was melted at 265°C and sheeted to a thickness of 140-180 μm. Figure 1 This is a SEM photo of the cross section of a polyester composition sample. Figure 1It can be seen that the maleic anhydride copolymer microspheres have uniform particle size and are evenly distributed in the polyester matrix.

[0150] Example 2

[0151] Preparation of polyester compositions

[0152] 100 parts of PET-1 were dried at 140°C for 5 hours and blended with 15 parts of maleic anhydride copolymer microspheres A1, 0.75 parts of antioxidant, and 0.1 parts of heat stabilizer triphenyl phosphate in a high-speed blender. The antioxidants used were pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1010) and (2,4-di-tert-butylphenyl)trisphosphite, and the weight ratio of the two was 1:1.

[0153] The homogenized pellets were added to a twin-screw extruder for pelletization. The temperatures of the feed section, melting section, homogenizing section, and die head of the twin-screw extruder were set at 220°C, 240°C, 265°C, and 260°C, respectively, and the screw speed was 150 r / min. The polyester composition of the present invention was pelletized. The polyester composition was dried at 140°C for 12 hours and then tested for its properties. The performance results are shown in Table 1.

[0154] Example 3

[0155] Preparation of polyester compositions

[0156] 100 parts of PET-2 were dried at 140°C for 5 hours and blended with 45 parts of maleic anhydride copolymer microspheres A1, 0.75 parts of antioxidant, and 0.1 parts of heat stabilizer triphenyl phosphate in a high-speed blender. The antioxidants used were pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Antioxidant 1010) and (2,4-di-tert-butylphenyl)trisphosphite, and the weight ratio of the two was 1:1.

[0157] The homogenized pellets were added to a twin-screw extruder for pelletization. The temperatures of the feed section, melting section, homogenizing section, and die head of the twin-screw extruder were set at 220°C, 240°C, 265°C, and 260°C, respectively, and the screw speed was 150 r / min. The polyester composition of the present invention was pelletized. The polyester composition was dried at 140°C for 12 hours and then tested for its properties. The performance results are shown in Table 1.

[0158] Example 4

[0159] Preparation of polyester compositions

[0160] 100 parts of PET-3 were dried at 140°C for 5 hours and blended with 30 parts of maleic anhydride copolymer microspheres A2, 0.75 parts of antioxidant, and 0.1 parts of heat stabilizer triphenyl phosphate in a high-speed blender. The antioxidants used were pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Antioxidant 1010) and (2,4-di-tert-butylphenyl)trisphosphite, and the weight ratio of the two was 1:1.

[0161] The homogenized pellets were added to a twin-screw extruder for pelletization. The temperatures of the feed section, melting section, homogenizing section, and die head of the twin-screw extruder were set at 220°C, 240°C, 265°C, and 260°C, respectively, and the screw speed was 150 r / min. The polyester composition of the present invention was pelletized. The polyester composition was dried at 140°C for 12 hours and then tested for its properties. The performance results are shown in Table 1.

[0162] Example 5

[0163] Preparation of polyester compositions

[0164] 100 parts of PET-3 were dried at 140°C for 5 hours and blended with 30 parts of maleic anhydride copolymer microspheres A3, 0.75 parts of antioxidant, and 0.1 parts of heat stabilizer triphenyl phosphate in a high-speed blender. The antioxidants used were pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Antioxidant 1010) and (2,4-di-tert-butylphenyl)trisphosphite, and the weight ratio of the two was 1:1.

[0165] The homogenized pellets were added to a twin-screw extruder for pelletization. The temperatures of the feed section, melting section, homogenizing section, and die head of the twin-screw extruder were set at 220°C, 240°C, 265°C, and 260°C, respectively, and the screw speed was 150 r / min. The polyester composition of the present invention was pelletized. The polyester composition was dried at 140°C for 12 hours and then tested for its properties. The performance results are shown in Table 1.

[0166] Example 6

[0167] Preparation of polyester compositions

[0168] 100 parts of PET-1 were dried at 140°C for 5 hours and blended with 30 parts of maleic anhydride copolymer microspheres A4, 0.75 parts of antioxidant, and 0.1 parts of heat stabilizer triphenyl phosphate in a high-speed blender. The antioxidants used were pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Antioxidant 1010) and (2,4-di-tert-butylphenyl)trisphosphite, and the weight ratio of the two was 1:1.

[0169] The homogenized pellets were added to a twin-screw extruder for pelletization. The temperatures of the feed section, melting section, homogenizing section, and die head of the twin-screw extruder were set at 220°C, 240°C, 265°C, and 260°C, respectively, and the screw speed was 150 r / min. The polyester composition of the present invention was pelletized. The polyester composition was dried at 140°C for 12 hours and then tested for its properties. The performance results are shown in Table 1.

[0170] Example 7

[0171] Preparation of polyester compositions

[0172] 100 parts of PET-1 were dried at 140°C for 5 hours and blended with 58 parts of maleic anhydride copolymer microspheres A1, 0.75 parts of antioxidant, and 0.1 parts of heat stabilizer triphenyl phosphate in a high-speed blender. The antioxidants used were pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Antioxidant 1010) and (2,4-di-tert-butylphenyl)trisphosphite, and the weight ratio of the two was 1:1.

[0173] The homogenized pellets were added to a twin-screw extruder for pelletization. The temperatures of the feed section, melting section, homogenizing section, and die head of the twin-screw extruder were set at 220°C, 240°C, 265°C, and 260°C, respectively, and the screw speed was 150 r / min. The polyester composition of the present invention was pelletized. The polyester composition was dried at 140°C for 12 hours and then tested for its properties. The performance results are shown in Table 1.

[0174] Comparative Example 1

[0175] 100 parts of PET-1 were dried at 140°C for 5 hours and blended with 5 parts of maleic anhydride copolymer microspheres A1, 0.75 parts of antioxidant, and 0.1 parts of heat stabilizer triphenyl phosphate in a high-speed blender. The antioxidants used were pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Antioxidant 1010) and (2,4-di-tert-butylphenyl)trisphosphite, and the weight ratio of the two was 1:1.

[0176] The homogenized pellets were added to a twin-screw extruder for pelletization. The temperatures of the feed section, melting section, homogenizing section, and die head of the twin-screw extruder were set at 220°C, 240°C, 265°C, and 260°C, respectively, and the screw speed was 150 r / min. The polyester composition of the present invention was pelletized. The polyester composition was dried at 140°C for 12 hours and then tested for its properties. The performance results are shown in Table 1.

[0177] Comparative Example 2

[0178] 100 parts of PET-1 were dried at 140℃ for 5h, and then blended with 30 parts of nano-CaCO3 powder (Shanghai Yinjiang Chemical Co., Ltd., 10000 mesh), 0.75 parts of antioxidant, and 0.1 parts of heat stabilizer triphenyl phosphate in a high-speed mixer, wherein the antioxidant was selected from tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) pentaerythritol ester (antioxidant 1010) and (2,4-di-tert-butylphenyl) phosphite, and the weight ratio of the two was 1:1.

[0179] The mixed granules were added to a twin-screw extruder for granulation, and the temperatures of the feeding section, melting section, homogenizing section and die of the twin-screw extruder were 220℃, 240℃, 265℃ and 260℃ respectively, and the rotation speed of the screw was 150 r / min, to obtain the polyester composition of the present application. The polyester composition was dried at 140℃ for 12h, and then the performance of the polyester composition was tested, and the performance results are shown in Table 1. The polyester composition was melted at 265℃ and then tabletted, and the thickness of the sample tablet was 140-180μm. Figure 2 is an SEM photo of the cross section of the polyester composition sample tablet. It can be seen from Figure 2 that the inorganic powder is obviously agglomerated.

[0180] Comparative Example 3

[0181] 100 parts of PET-1 were dried at 140℃ for 5h, and then blended with 30 parts of nano-BaSO4 powder (Sahali Blanc Fixe Micro, organic coated, d50=0.7μm), 0.75 parts of antioxidant, and 0.1 parts of heat stabilizer triphenyl phosphate in a high-speed mixer, wherein the antioxidant was selected from tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) pentaerythritol ester (antioxidant 1010) and (2,4-di-tert-butylphenyl) phosphite, and the weight ratio of the two was 1:1.

[0182] The mixed granules were added to a twin-screw extruder for granulation, and the temperatures of the feeding section, melting section, homogenizing section and die of the twin-screw extruder were 220℃, 240℃, 265℃ and 260℃ respectively, and the rotation speed of the screw was 150 r / min, to obtain the polyester composition of the present application. The polyester composition was dried at 140℃ for 12h, and then the performance of the polyester composition was tested, and the performance results are shown in Table 1. The polyester composition was melted at 265℃ and then tabletted, and the thickness of the sample tablet was 140-180μm. Figure 3 is an SEM photo of the cross section of the polyester composition sample tablet. It can be seen from Figure 3 that the inorganic powder is obviously agglomerated.

[0183] Comparative Example 4

[0184] 100 parts of PET-1 were dried at 140℃ for 5h, and then blended with 80 parts of maleic anhydride copolymer microspheres A1, 0.75 parts of antioxidant, and 0.1 parts of heat stabilizer triphenyl phosphate in a high-speed mixer, wherein the antioxidant is selected from tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) pentaerythritol ester (antioxidant 1010) and (2,4-di-tert-butylphenyl) phosphite, and the weight ratio of the two is 1:1.

[0185] The mixed granules were added to a twin-screw extruder for granulation, and the temperatures of the feeding section, melting section, homogenizing section and die of the twin-screw extruder were 220℃, 240℃, 265℃ and 260℃ respectively, and the rotation speed of the screw was 150r / min, to obtain the polyester composition of the present application. The polyester composition was dried at 140℃ for 12h, and then the performance of the polyester composition was tested, and the performance results are shown in Table 1.

[0186] Comparative Example 5

[0187] 100 parts of PET-1 were dried at 140℃ for 5h, and then blended with 30 parts of maleic anhydride copolymer microspheres A1, 0.75 parts of antioxidant, and 0.1 parts of heat stabilizer triphenyl phosphate in a high-speed mixer, wherein the antioxidant is selected from tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) pentaerythritol ester (antioxidant 1010) and (2,4-di-tert-butylphenyl) phosphite, and the weight ratio of the two is 1:1.

[0188] The mixed granules were added to a twin-screw extruder for granulation, and the temperatures of the feeding section, melting section, homogenizing section and die of the twin-screw extruder were 220℃, 240℃, 265℃ and 260℃ respectively, and the rotation speed of the screw was 150r / min, to obtain the polyester composition of the present application. The polyester composition was dried at 140℃ for 12h, and then the performance of the polyester composition was tested, and the performance results are shown in Table 1.

[0189] Table 1

[0190]

[0191] As can be seen from Table 1, the difference (△H mPET and △H m组合物 ) between the melting enthalpy of the polyester composition provided by the present application and the polyester satisfies the range of the present application, which indicates that the composition provided by the present application can improve the uniformity of the dispersion of the maleic anhydride copolymer microspheres in the matrix resin without using any coupling agent, dispersant and compatibilizer, so that the polyester composition can meet the requirements of the stretching ratio and reflectivity of the reflective film.

[0192] Test Example

[0193] The polyester composition of the examples and comparative examples was melt-extruded at 275°C using a single-screw extruder with a length-diameter ratio of more than 40, and then extruded into a single layer thick sheet using a single layer T-shaped die, and then cooled to 30-60°C using a roller through which cold water at 20°C was passed, to produce a polyester cast sheet. The cast sheet was preheated at 80-180°C, and then stretched by 2-5 times in a single axis to produce a polyester film, which was then passed through a heat setting zone of an electrically heated tunnel, at a heat setting temperature of 100-200°C, and then cooled at 60-80°C, to finally produce a light reflecting polyester film having an average thickness of 0.1-0.3 mm.

[0194] Table 2

[0195] Item Reflectance (%) Example 1 97.2 Example 2 96.7 Example 3 96.8 Example 4 96.7 Example 5 96.8 Example 6 96.6 Example 7 96.5 Comparative Example 1 95.2 Comparative Example 2 95.5 Comparative Example 3 95.6 Comparative Example 4 95.5 Comparative Example 5 95.7

[0196] As can be seen from Table 2, the reflectivity of the light reflecting film produced from the polyester composition of the present application is greater than 96%, indicating that the light reflecting film does not have a problem of dark shadows around it during use, can reduce light loss, and exhibits excellent light reflecting performance, and can be applied to an ultra-thin direct type backlight film set.

[0197] The above describes preferred embodiments of the present application, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application, and all fall within the protection scope of the present application.

Claims

1. A polyester composition, characterized in that The polyester composition comprises polyester, maleic anhydride copolymer microspheres and an auxiliary agent; Based on 100 parts of the polyester, the amount of the maleic anhydride copolymer microspheres is 10-60 parts, and the amount of the auxiliary agent is 0.1-15 parts; The average particle size of the maleic anhydride copolymer microspheres is 500-1600 nm; The melting enthalpy of the polyester is △ H mPET , the melting enthalpy of the polyester composition is △ H m组合物 ; in, △ H mPET and △ H m组合物 The difference is 6-28 J / g; The maleic anhydride copolymer microspheres contain a structural unit A derived from maleic anhydride and a structural unit B derived from a comonomer. Based on the total molar amount of each structural unit in the copolymer, the molar content of the structural unit A is 48-55%; the molar content of the structural unit B is 45-52%. The comonomer is selected from at least one of styrene, α-methylstyrene, vinyl acetate, C4 olefins and C5 olefins; The polyester is polyethylene terephthalate.

2. The polyester composition according to claim 1, wherein Based on 100 parts of the polyester, the amount of the maleic anhydride copolymer microspheres is 12-50 parts, and the amount of the auxiliary agent is 0.3-12 parts.

3. The polyester composition according to claim 1 or 2, wherein The average particle size of the maleic anhydride copolymer microspheres is 600-1300 nm.

4. The polyester composition according to claim 1 or 2, wherein △ H mPET and △ H m组合物 The difference is 8-25 J / g.

5. The polyester composition according to claim 1 or 2, wherein The molar content of the structural unit A is 49-51%; the molar content of the structural unit B is 49-51%.

6. The polyester composition according to claim 1 or 2, wherein The preparation method of the maleic anhydride copolymer microspheres comprises the following steps: (1) In an inert atmosphere, maleic anhydride, comonomer and initiator are dissolved in a reaction medium to form a homogeneous solution; (2) the homogeneous solution is polymerized to obtain a copolymer emulsion suspension, and then solid-liquid separation is performed to obtain the maleic anhydride copolymer microspheres; Wherein, based on the total weight of maleic anhydride and the comonomer, the amount of maleic anhydride is 50-90wt%, and the amount of the comonomer is 10-50wt%; The reaction medium is a mixture of the compound represented by formula (1) and an alkane; Formula (1), Wherein, R1 and R2 are each independently an alkyl group having 1 to 6 carbon atoms.

7. The polyester composition according to claim 6, wherein The comonomer is selected from at least one of styrene, α-methylstyrene and vinyl acetate.

8. The polyester composition according to claim 6, wherein Based on the total weight of the homogeneous solution, the total mass concentration of the maleic anhydride and the comonomer is 5-25wt%; and / or, based on the total weight of the homogeneous solution, the mass concentration of the initiator is 0.01-5wt%; And / or, based on the total weight of maleic anhydride and the comonomer, the amount of maleic anhydride used is 50-60 wt%, and the amount of the comonomer used is 40-50 wt%.

9. The polyester composition according to claim 8, wherein Based on the total weight of the homogeneous solution, the total mass concentration of the maleic anhydride and the comonomer is 5-20wt%; And / or, based on the total weight of the homogeneous solution, the mass concentration of the initiator is 1-4 wt %.

10. The polyester composition according to claim 6, wherein In formula (1), R1 and R2 are each independently a methyl group or an ethyl group; and / or, the alkane is an alkane having 6 to 12 carbon atoms; And / or, based on the total volume of the reaction medium, the amount of the alkane used is 50-90 vol%.

11. The polyester composition according to claim 10, wherein The amount of the alkane used is 60-80 vol% based on the total volume of the reaction medium.

12. The polyester composition according to claim 6, wherein The polymerization reaction conditions include: polymerization temperature of 61-100° C.; polymerization time of 1-24 h.

13. The polyester composition according to claim 12, wherein The polymerization reaction conditions include: polymerization temperature of 70-90° C.; polymerization time of 2-12 hours.

14. The polyester composition according to claim 1 or 2, wherein The preparation method of the maleic anhydride copolymer microspheres comprises the following steps: In the presence of an inert atmosphere, an initiator and an organic solvent, maleic anhydride and a comonomer are copolymerized to prepare the maleic anhydride copolymer microspheres.

15. The polyester composition according to claim 14, wherein The comonomer is selected from mixed C4 and / or mixed C5; and / or, the weight ratio of maleic anhydride to the comonomer is 1:(0.2-3); and / or, based on the total weight of the maleic anhydride, the amount of the initiator is 0.05-20 mol%; and / or, the organic solvent is selected from at least one of isoamyl acetate, butyl acetate, isopropyl acetate and ethyl acetate; And / or, based on the total weight of the organic solvent, the concentration of the maleic anhydride is 5-25 wt %.

16. The polyester composition according to claim 15, wherein The weight ratio of the maleic anhydride to the comonomer is 1:(0.8-3); And / or, based on the total weight of the organic solvent, the concentration of the maleic anhydride is 10-20 wt %.

17. The polyester composition according to claim 14, wherein The copolymerization reaction conditions include: copolymerization reaction temperature of 50-100° C.; copolymerization reaction pressure of 0.2-2 MPa; and copolymerization reaction time of 5-10 h.

18. The polyester composition according to claim 17, wherein The copolymerization reaction conditions include: copolymerization reaction temperature of 70-90° C.; copolymerization reaction pressure of 0.5-1 MPa; and copolymerization reaction time of 6-9 hours.

19. The polyester composition according to claim 1 or 2, wherein At 25° C., the intrinsic viscosity of the polyester is 0.62-0.88 dL / g.

20. The polyester composition according to claim 1 or 2, wherein The glass transition temperature of the polyester is 65-85°C.

21. The polyester composition according to claim 1 or 2, wherein The melting point of the polyester is 240-265°C.

22. The polyester composition according to claim 1 or 2, wherein The crystallization temperature of the polyester is 168-192°C.

23. The polyester composition according to claim 1 or 2, wherein The polyester composition further comprises at least one organic particle selected from the group consisting of polyethylene, polystyrene, polypropylene, polybutene, poly-4-methyl-1-pentene, cyclic olefin copolymer, polymethacrylic acid, silicone resin, ethylene-methyl methacrylate copolymer and ethylene-vinyl acetate copolymer.

24. The polyester composition according to claim 1 or 2, wherein The auxiliary agent includes at least one of an antioxidant, a heat stabilizer, an antistatic agent, an anti-hydrolysis agent, a nucleating agent, a flame retardant and an ultraviolet absorber.

25. The polyester composition according to claim 24, wherein The antioxidant is at least one selected from the group consisting of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris(2,4-di-tert-butyl)phenyl phosphite, octadecyl propionate, and alkylated polyphenols; And / or, the thermal stabilizer is a phosphorus-based thermal stabilizer; and / or, the antistatic agent is selected from at least one of ethoxylated alkylamines, tetraalkylammonium salts, alkylbenzene sulfonates, alkyl sulfonates, polyetheresteramides, polyetheramideimides, and copolymers of methoxypolyethylene glycol and methacrylate; and / or, the anti-hydrolysis agent is selected from carbodiimides'; And / or, the nucleating agent is at least one selected from the group consisting of inorganic salt nucleating agents, organic acid salt nucleating agents, ionomer nucleating agents, and alkali metal salt nucleating agents of polyester oligomers; and / or, the flame retardant is selected from brominated organic flame retardants and / or inorganic flame retardants; And / or, the ultraviolet absorber is selected from at least one of methyl o-hydroxybenzoate, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2,4-dihydroxybenzophenone and 2-hydroxy-4-n-octyloxybenzophenone.

26. The polyester composition according to claim 25, wherein The heat stabilizer is selected from at least one of trimethyl phosphate, triphenyl phosphate and triethyl phosphate; And / or, the anti-hydrolysis agent is at least one selected from dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide and polycarbodiimide.

27. The polyester composition according to claim 25, wherein The antioxidants are pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) and (2,4-di-tert-butylphenyl)trisphosphite; Alternatively, the antioxidant is n-octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and (2,4-di-tert-butylphenyl) phosphite triester.

28. The polyester composition according to claim 27, wherein The weight ratio of the pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) or the n-octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate to the (2,4-di-tert-butylphenyl)trisphosphite is 1-3:

1.

29. The polyester composition according to claim 1 or 2, wherein The polyester composition does not contain dispersant, compatibilizer and coupling agent.

30. Use of the polyester composition according to any one of claims 1 to 29 in an optical reflective film.

31. A method for preparing the polyester composition according to any one of claims 1 to 29, characterized in that: The method comprises: (1) mixing polyester, maleic anhydride copolymer microspheres and an additive to obtain a mixture; (2) The mixture is melt-blended, extruded, pelletized, and dried in a twin-screw extruder to obtain the polyester composition.

32. The preparation method according to claim 31, wherein The rotation speed of the twin-screw extruder is 80-300 r / min.

33. The preparation method according to claim 32, wherein The temperatures of the feeding section, melting section, homogenizing section and die head of the twin-screw extruder are 200-230° C., 240-260° C., 255-275° C. and 250-270° C. respectively.

34. An optical reflective film, characterized in that: The optical reflective film is made from the polyester composition according to any one of claims 1 to 29.

Images