Microspherical maleic anhydride copolymerization modifier as well as preparation method and application thereof

Abstract

The invention relates to a microsphere-shaped maleic anhydride copolymerization modifier as well as a preparation method and application thereof, belonging to the field of high polymer materials. The microsphere-shaped maleic anhydride copolymerization modifier is obtained by combining alkali metal ions after acid anhydride of a maleic anhydride copolymer is subjected to ring opening; the weight fraction of alkali metal ions of the microsphere-shaped maleic anhydride copolymerization modifier is 1%-22%, preferably 2%-20%; the maleic anhydride copolymer is a maleic anhydride linear copolymer; the morphology of the microsphere-shaped maleic anhydride copolymerization modifier is spherical or sphere-like, and preferably, the average particle size of the microsphere-shaped maleic anhydride copolymerization modifier is 2-15 [mu] m. The microsphere-shaped maleic anhydride copolymerization modifier is well dispersed in polyester such as PET (Polyethylene Terephthalate) and the like, and can accelerate the crystallization speed of the PET.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, and more specifically, to a microspherical maleic anhydride copolymer modified with the same, its preparation method, and its application. Background Technology

[0002] Maleic anhydride, a commonly used polymerizing monomer, can copolymerize with various monomers to form alternating, random, and block copolymers, which have wide applications in medicine, agriculture, and fine chemicals. To further expand the application range of maleic anhydride copolymers, various modifications are often performed to impart new functions.

[0003] Maleic anhydride copolymers contain abundant anhydride groups, which can react with various groups, such as esterification, amination, and acid-base neutralization. Acid-base neutralization is the simplest chemical reaction, and the resulting product can form ionomers, widely used as nucleating agents, antibacterial agents, and UV stabilizers. Chinese Patent CN111793167A discloses a zinc salt derivative of a maleic anhydride copolymer, in which zinc is linked to the anhydride after ring-opening, exhibiting antibacterial and fluorescent properties. Chinese Patent CN109705249A uses maleic anhydride copolymers, alkali, and saturated monohydric alcohols to prepare ionomers that can be used as PET nucleating agents. Chinese Patent CN109705251A uses maleic anhydride crosslinked copolymers and alkali for salting to obtain microsphere-like ionomers with crosslinked structures, exhibiting nucleation effects on PET. Xing et al. (Poly(styrene-co-maleicanhydride)ionomers as nucleating agent on the crystallization behavior of poly(ethylene terephthalate). J. Appl. Polym. Sci., 132, 41240, doi:10.1002 / app.41240) prepared maleic anhydride-styrene ionomers by mixing a commercially available dioxane solution of maleic anhydride-styrene copolymer with a methanol solution of sodium hydroxide, thus verifying its application as a nucleating agent in PET.

[0004] The methods described above require the use of maleic anhydride crosslinked copolymers, the introduction of monohydric alcohols for esterification, or the use of high-valence metal ions to induce precipitation of maleic anhydride. These techniques are currently unable to modify linear maleic anhydride copolymers to obtain microspherical alkali metal-modified maleic anhydride copolymers. Therefore, developing a novel microspherical linear maleic anhydride copolymer is of significant practical importance. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention proposes a microspherical maleic anhydride copolymer modifier. Specifically, it relates to a microspherical maleic anhydride copolymer modifier, its preparation method, and its applications. The technical solution uses a linear maleic anhydride copolymer as a matrix. After salification, the microspherical modifier is prepared by controlling conditions such as the viscosity and concentration of the solution and the molecular weight of the linear maleic anhydride copolymer used. It disperses well in polyesters such as PET and can accelerate the crystallization rate of PET.

[0006] One objective of this invention is to provide a microspherical maleic anhydride copolymer modified material, wherein the maleic anhydride copolymer modified material is an alkali metal modified maleic anhydride copolymer; it is obtained by ring-opening of the anhydride of the maleic anhydride copolymer and then combining it with alkali metal ions, and the weight fraction of the alkali metal ions can be 1%-22%, preferably 2%-20%. For example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or any value between the above values ​​or a range between any two of the above values, such as 3%-15%, 5%-19%, etc.

[0007] In one specific embodiment of the present invention, the microspherical maleic anhydride copolymer is a maleic anhydride copolymer in which alkali metal ions are bonded to the carboxylic acid groups.

[0008] The morphology of the microspherical maleic anhydride copolymer modified by the description is spherical or near-spherical, with an average particle size of 2-15 μm, preferably 4-12 μm. Specifically, it can be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, or any value between the above values ​​or a range between any two of the above values, such as 4-10 μm, 5-11 μm, etc.

[0009] According to a preferred embodiment of the present invention, the maleic anhydride copolymer can be any existing linear maleic anhydride copolymer, more preferably at least one of linear alternating maleic anhydride copolymers, and even more preferably a linear alternating maleic anhydride copolymer obtained by combining structural unit A provided by maleic anhydride and structural unit B provided by monomer M; the monomer M is selected from monomers containing isolated carbon-carbon double bonds, preferably at least one of vinyl acetate, C4 olefin, C4 fraction, C5 olefin, C5 fraction, C8 olefin, C8 fraction, C9 olefin, and C9 fraction, and more preferably at least one of vinyl acetate, styrene, α-methylstyrene, C4 olefin, C4 fraction, C5 olefin, and C5 fraction.

[0010] The C4 olefins, C5 olefins, C8 olefins, and C9 olefins refer to olefins or mixtures of olefins that each contain 4, 5, 8, or 9 carbon atoms. For example, a C4 olefin may be a mixture of one or more olefins containing 4 carbon atoms; a C5 olefin may be a mixture of one or more olefins containing 5 carbon atoms; a C8 olefin may be a mixture of one or more olefins containing 8 carbon atoms; and a C9 olefin may be a mixture of one or more olefins containing 9 carbon atoms.

[0011] The C4 and C5 fractions can be selected from C4 or C5 fractions from the oil refining or ethylene industry, preferably from C4 or C5 fractions obtained from ethylene cracking in the petrochemical industry; the C8 and C9 fractions can be selected from C8 or C9 fractions from the steam cracking process for ethylene production in the petrochemical industry, the naphtha platinum reforming process, and coal tar.

[0012] The number-average molecular weight of the maleic anhydride copolymer may be less than 30,000 g / mol, preferably less than 25,000 g / mol.

[0013] The structural characteristics of the microspherical maleic anhydride copolymer modified by the following method are: the maleic anhydride in the maleic anhydride copolymer reacts with an alkali metal inorganic salt, and after ring opening, the maleic anhydride is linked to one and / or two alkali metal ions. Preferably, the alkali metal is selected from at least one of lithium, sodium, potassium, rubidium, cesium, and francium, and more preferably from at least one of lithium, sodium, and potassium.

[0014] A second objective of this invention is to provide a method for preparing the microspherical maleic anhydride copolymer modifier, comprising the following steps: thoroughly mixing and reacting a solid maleic anhydride copolymer with an aqueous solution of an alkali metal inorganic salt, and then drying by spray drying to obtain the microspherical maleic anhydride copolymer modifier. Specifically, the method may include the following steps:

[0015] (a) Preparation of aqueous solution of alkali metal inorganic salt; specifically, taking alkali metal inorganic salt, adding it to water to dissolve it, and obtaining aqueous solution of alkali metal inorganic salt;

[0016] (b) Add the maleic anhydride copolymer to the aqueous solution of the alkali metal inorganic salt from step (a) and allow it to react fully.

[0017] It should form a solution; this solution is a transparent solution.

[0018] (c) The solution obtained in step (b) is spray-dried, and the collected powder is the microspherical maleic anhydride copolymer modified product.

[0019] in,

[0020] In step (a),

[0021] In a preferred embodiment of the present invention, the alkali metal inorganic salt may be selected from at least one of alkali metal hydroxides, alkali metal carbonates, alkali metal bicarbonates, alkali metal sulfates, and alkali metal nitrates, preferably at least one of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates, and more preferably at least one of alkali metal hydroxides.

[0022] In step (b),

[0023] In a preferred embodiment of the present invention, the maleic anhydride copolymer is a linear maleic anhydride copolymer. The linear maleic anhydride copolymer can be any of the existing linear maleic anhydride copolymers, preferably at least one of linear alternating maleic anhydride copolymers, and more preferably a linear alternating maleic anhydride copolymer obtained by combining structural unit A provided by maleic anhydride and structural unit B provided by monomer M. The monomer M is selected from monomers containing isolated carbon-carbon double bonds, preferably at least one of vinyl acetate, C4 olefin, C4 fraction, C5 olefin, C5 fraction, C8 olefin, C8 fraction, C9 olefin, and C9 fraction; preferably at least one of vinyl acetate, styrene, α-methylstyrene, C4 olefin, C4 fraction, C5 olefin, and C5 fraction.

[0024] In a preferred embodiment of the present invention, the molar ratio of the maleic anhydride copolymer (calculated by anhydride groups) to the alkali metal inorganic salt (calculated by alkali metal element) is 1:(0.1-4), preferably 1:(0.2-3), and more preferably 1:(0.5-2.5); the reaction is an acid-base neutralization reaction between the anhydride groups of the maleic anhydride copolymer and the alkali metal inorganic salt. Specifically, the ratio can be 1:0.1, 1:0.2, 1:0.4, 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2.0, 1:2.2, 1:2.5, 1:2.8, 1:3.0, 1:3.2, 1:3.5, 1:3.8, 1:4.0, or any value between the above values ​​or a range between any two of the above values.

[0025] In a preferred embodiment of the present invention, the amount of the maleic anhydride copolymer used is 0.1%-15% of the weight of the solution obtained in step (b), preferably 0.1%-10%. For example, it can be 0.1%, 0.5%, 1.0%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any value between the above values ​​or a range between any two of the above values, such as 3%-10%.

[0026] In a preferred embodiment of the present invention, the number average molecular weight of the maleic anhydride copolymer is less than 30,000 g / mol, preferably less than 25,000 g / mol; for example, it can be any value between the above values ​​such as 5,000, 8,000, 10,000, 15,000, 18,000, 20,000, 22,000, 25,000, 28,000, 29,000, 29,500 g / mol, or a range between any two of the above values, such as 5,000–29,500 g / mol, 10,000–29,500 g / mol, 15,000–25,000 g / mol, etc.

[0027] The reaction in step (b) can be stopped once a transparent solution is formed. There are no particular restrictions on the reaction temperature and pressure; the reaction temperature can be 5–95°C, preferably room temperature; the reaction pressure is preferably atmospheric pressure. There are also no particular restrictions on the equipment used for the reaction; conventional solution reaction equipment from the prior art can be used.

[0028] In a preferred embodiment of the present invention, the viscosity of the solution obtained in step (b) is less than 100 mPa·s, preferably less than 80 mPa·s, more preferably less than 70 mPa·s, for example, preferably less than 60 mPa·s, for example, preferably less than 50 mPa·s. For example, any value between the above values, or a range between any two of the above values, such as 5, 10, 15, 20, 25, 30, 40, 45, 50, 60, 65, 70, 80, 85, 90, 95 mPa·s. The viscosity can be tested using conventional instruments in the art. The testing equipment and method used here are: Fangrui NDJ-5S equipment, using a #2 rotor, and a rotation speed of 60 RPM.

[0029] In step (c),

[0030] The spray drying inlet air temperature is 150℃-200℃, preferably 155℃-180℃; the outlet air temperature is 60℃-100℃, preferably 70-95℃.

[0031] In the preparation of the microspherical maleic anhydride copolymer modified by this invention, spherical or near-spherical modified products can be obtained by using the number-average molecular weight and solution viscosity of the specific maleic anhydride copolymer of this invention. When the number-average molecular weight or solution viscosity of the maleic anhydride copolymer exceeds the conditions defined by this invention, the molecular chains in the solution are tightly entangled, which easily leads to problems such as slow solution drying speed and wall adhesion, or product stringing and sticking during spray drying. Within the preferred range of this invention, the entanglement concentration of polymer molecular chains is appropriate, and relatively uniform particles can be formed during spray drying. The particles are more uniformly dispersed in PET, which is more conducive to improving the crystallization properties of PET.

[0032] The third objective of this invention is to provide a microspherical maleic anhydride copolymer modified product prepared by the method described in this invention.

[0033] The fourth objective of this invention is to provide applications of the microspherical maleic anhydride copolymer modified by the present invention or the products prepared by the preparation method, preferably in PET.

[0034] The fifth objective of this invention is to provide a PET composition comprising PET and a microspherical maleic anhydride copolymer modifier; wherein the weight ratio of PET to the microspherical maleic anhydride copolymer modifier is 100:(0.1-10), preferably 100:(0.1-5), specifically 100:01, 100:0.2, 100:0.3, 100:0.4, 100:0.5, 100:0.6, 100 The ratios are 0.7, 100:0.8, 100:0.9, 100:1.0, 100:1.2, 100:1.4, 100:1.6, 100:1.8, 100:2.0, 100:2.5, 100:3.0, 100:3.5, 100:4.0, 100:4.5, 100:5.0, or any value between the above or a range between any two of the above values. The composition is prepared using conventional thermoplastic processing methods, such as twin-screw extrusion, single-screw extrusion, internal mixing, injection molding, casting, etc. The thermoplastic processing temperature is the standard PET condition and will not be elaborated here.

[0035] The inventors of this application discovered in their research that, under the specific molecular weight and solution viscosity conditions of this invention, a microspherical modified maleic anhydride copolymer can be obtained after mixing a linear copolymer of maleic anhydride with an alkali metal inorganic salt solution. The main advantages of this invention are:

[0036] (1) The maleic anhydride copolymer is a by-product of industrial polyolefin synthesis, and the raw materials are readily available and the industrial production process is mature.

[0037] (2) The preparation process of the microsphere maleic anhydride copolymer modifier is an industrially mature spray drying process, which is easy to scale up and promote in industry.

[0038] (3) The linear copolymer of maleic anhydride used in the microspherical maleic anhydride copolymer modified by this application, compared with the cross-linked copolymer microspheres, has the disadvantage that the cross-linked copolymer microspheres require the addition of a multifunctional monomer during the polymerization process to cause a cross-linking reaction. When the cross-linked microspheres are modified, their particle size does not change much, and there may be insufficient reaction inside the cross-linked microspheres during the modification process. In contrast, the linear copolymer microspheres can be completely dissolved in good solvents, have more modification techniques, and have a wider range of applications.

[0039] (4) The microspherical maleic anhydride copolymer modifier has small particle size, high sphericity and does not agglomerate. It can be uniformly dispersed in PET and can effectively improve the crystallization performance of PET, increase the crystallization temperature and reduce parameters such as half width at half maximum. Attached Figure Description

[0040] Figure 1 This is a scanning electron microscope (SEM) image of the microspherical maleic anhydride copolymer modified in Example 1;

[0041] Figure 2 SEM image of the maleic anhydride copolymer modified in Comparative Example 1;

[0042] Figure 3 SEM images of the maleic anhydride copolymer modified in Comparative Example 2;

[0043] Figure 4 SEM image of maleic anhydride-styrene crosslinked copolymer, Comparative Example 3;

[0044] Figure 5 SEM images of the maleic anhydride copolymer modified in Comparative Example 3;

[0045] Figure 6 This is a SEM image of the maleic anhydride copolymer modified in Example 2. Detailed Implementation

[0046] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0047] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0048] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0049] 1. The raw materials used in the examples and comparative examples include:

[0050] Maleic anhydride, styrene, isoamyl acetate, azobisisobutyronitrile, and sodium hydroxide were all purchased from Inokai, analytical grade; C4 fraction: mixed C4 from Zhenhai Refining & Chemical; PET from Yizheng Chemical Fiber, grade: BG85.

[0051] The maleic anhydride-styrene linear alternating copolymer (MSL) used in the examples was prepared according to the method described in the published literature (A new family of thermoplastic photoluminescence polymers. Polym. Chem., 2016, 7, 6250-6256). The main preparation conditions and parameters were as follows: the molar ratio of maleic anhydride to styrene was 1:1, the medium was isoamyl acetate, the initiator was azobisisobutyronitrile, the ratio of monomer to medium was (0.05-0.5):1, the reaction temperature was (50℃-85℃), and the reaction time was (0.5h-12h). The molecular weight was adjusted by adjusting the reaction concentration, temperature, and time to prepare maleic anhydride-styrene linear alternating copolymers (MSL) with molecular weights of 19800 g / mol, 23800 g / mol, and 42000 g / mol, respectively, for later use.

[0052] The maleic anhydride-C4 linear alternating copolymer (MC4L) used in the examples was prepared according to the method described in Example 1 of Chinese Patent Publication No. CN107722177A. The main preparation conditions and parameters were as follows: the reaction monomers were maleic anhydride (20 kg) and mixed C4A (14 kg); the medium was isoamyl acetate (100 L); and the initiator was azobisisobutyronitrile (2.4 kg). The composition (weight percentage) of the mixed C4A was as follows: 1,2-butadiene, 8.92%; 1,3-butadiene, 14.14%; 1-butene, 8.38%; trans-2-butene, 5.84%; cis-2-butene, 31.7%; vinylacetylene, 10.99%; isobutane, 1.3%; isobutene, 12.78%; n-butane, 2.58%; and others, 3.37%. The reaction temperature was 75°C, and the reaction time was 6 h. A maleic anhydride-C4 linear alternating copolymer (MC4L) with a number average molecular weight of 17000 g / mol was prepared and set aside for later use.

[0053] 2. The experimental data for the examples and comparative examples were determined using the following methods:

[0054] (1) Solution viscosity: Fangrui NDJ-5S, No. 2 rotor, speed 60RPM.

[0055] (2) Scanning Electron Microscopy (SEM): The sample was adhered to conductive adhesive, sputtered with gold, and then observed using a CoxEM EM-30 scanning electron microscope. The elemental composition and content were determined using the energy dispersive spectroscopy (EDS) spectrometer built into the SEM.

[0056] (3) Crystallization performance test: The PerkinElmer DSC8000 was used to test the sample, and the heating and cooling rates were 10℃ / min.

[0057] Preparation of microspherical maleic anhydride copolymer modified:

[0058] Example 1:

[0059] Dissolve 15g of sodium hydroxide in 935g of water, and weigh 50g of MSL (number-average molecular weight 23800g / mol) and add it to the sodium hydroxide aqueous solution. After forming a transparent solution (viscosity 34.5mPa·s), spray dry it at an inlet air temperature of 180℃ and an outlet air temperature of 80℃. The collected powder is the microspherical maleic anhydride copolymer modified product. Its SEM image is shown below. Figure 1 As shown, the average particle size (average particle size measurement method: select 500 microspheres in the electron microscope image, measure their diameter, and calculate the average particle size of the microspheres by mathematical averaging) of the microsphere copolymer modified product is 6.2 μm, and the sodium element weight content is 8.3%.

[0060] Comparative Example 1:

[0061] Dissolve 15g of sodium hydroxide in 935g of water, and weigh 50g of MSL (number-average molecular weight 42000g / mol) and add it to the sodium hydroxide aqueous solution. After forming a transparent solution (viscosity 122.5mPa·s), spray dry it at an inlet air temperature of 180℃ and an outlet air temperature of 80℃. The collected powder is the maleic anhydride copolymer modified product. This is determined by experimental phenomena and SEM images (…). Figure 2 It can be seen that the product exhibits a phenomenon of solution sticking to the wall and flowing, and that there is adhesion between particles.

[0062] Comparative Example 2:

[0063] Dissolve 30g of sodium hydroxide in 870g of water. Weigh 100g of MSL (MSL same as in Example 1, number-average molecular weight 23800g / mol) and add it to the sodium hydroxide aqueous solution. After forming a homogeneous solution (viscosity 109.5mPa·s), spray dry it at an inlet air temperature of 180℃ and an outlet air temperature of 80℃. The collected powder is the microspherical maleic anhydride copolymer modified product. Its SEM image is shown below. Figure 3 As shown, the product exhibits a phenomenon of solution adhesion and flow, and there is adhesion between particles.

[0064] Comparative Example 3:

[0065] Dissolve 15g of sodium hydroxide in 935g of water. Weigh 50g of maleic anhydride-styrene crosslinked microspheres (the polymerization process of these microspheres is the same as the MSL preparation method in Example 1, except that during the polymerization process, divinylbenzene at a weight fraction of 5% of the monomer is added together with the monomers). SEM images of the crosslinked microspheres are shown below. Figure 4 (As shown) was added to an aqueous solution of sodium hydroxide. After the reaction was complete, the product was centrifuged at 5000 rad / min for 20 minutes, washed with deionized water, and centrifuged twice more. Finally, it was vacuum dried to obtain the maleic anhydride copolymer modified product. Its SEM image is shown below. Figure 5 As shown, it can be seen that, compared with the unmodified cross-linked microspheres, the particle size of the modified product remains almost unchanged, but there is aggregation and adhesion between the microspheres.

[0066] Example 2:

[0067] Dissolve 10g of sodium hydroxide in 465g of water, and weigh 25g of MSL (number-average molecular weight 19800g / mol) and add it to the sodium hydroxide aqueous solution. After forming a transparent solution (viscosity 24.5mPa·s), spray dry it at an inlet air temperature of 170℃ and an outlet air temperature of 70℃. The collected powder is the microspherical maleic anhydride copolymer modified product. Its SEM image is shown below. Figure 6 As shown, the average particle size of the product, the microspherical maleic anhydride copolymer modified, is 8.6 μm, and the sodium content by weight is 13.3%.

[0068] Example 3:

[0069] Dissolve 4g of sodium hydroxide in 76.5g of water, and weigh 7g of MC4L (number-average molecular weight 17000g / mol) and add it to the sodium hydroxide aqueous solution. After forming a transparent solution (viscosity 55.5mPa·s), spray dry it at an inlet air temperature of 170℃ and an outlet air temperature of 70℃. The collected powder is the microspherical maleic anhydride copolymer modified product. The average particle size of the product microspherical maleic anhydride copolymer modified product is 10.2μm, and the sodium elemental content is 18.4% by weight.

[0070] Example 4:

[0071] Dissolve 1g of sodium hydroxide in 994g of water, and weigh 5g of MSL (number-average molecular weight 29000g / mol) and add it to the sodium hydroxide aqueous solution. After forming a transparent solution (viscosity 22.5mPa·s), spray dry it at an inlet air temperature of 170℃ and an outlet air temperature of 70℃. The collected powder is the microspherical maleic anhydride copolymer modified product. The average particle size of the product, the microspherical maleic anhydride copolymer modified product, is 5.4μm, and the sodium elemental content is 6.5% by weight.

[0072] Preparation of PET composition:

[0073] Example 5:

[0074] 500g of PET (Yizheng Chemical Fiber, BG85) was blended with 1g of the microspherical maleic anhydride copolymer modified in Example 1, and then extruded and granulated in a twin-screw extruder. The crystallinity of the resulting PET-1 composition was analyzed by DSC.

[0075] Comparative Example 4:

[0076] 500g of PET (Yizheng Chemical Fiber, BG85) was extruded and granulated in a twin-screw extruder, and the crystallization properties of the resulting PET-2 composition were analyzed by DSC.

[0077] Comparative Example 5:

[0078] Dissolve 15g of sodium hydroxide in 935g of water, weigh 50g of MSL (number average molecular weight 23800g / mol) and add it to the sodium hydroxide aqueous solution, then dry it in an oven at 80℃ and grind it in a mortar to obtain the MSL modified product with an average particle size of 240μm.

[0079] 500g of PET (Yizheng Chemical Fiber, BG85) was blended with 1g of the above-mentioned MSL modifier, and then extruded and granulated in a twin-screw extruder. The crystallinity of the resulting PET-3 composition was analyzed by DSC.

[0080] Comparative Example 6:

[0081] 500g of PET (Yizheng Chemical Fiber, BG85) was blended with 1g of the maleic anhydride copolymer modified by Comparative Example 3, and then extruded and granulated in a twin-screw extruder. The crystallinity of the resulting PET-4 composition was analyzed by DSC.

[0082] Example 6:

[0083] 500g of PET (Yizheng Chemical Fiber, BG85) was blended with 0.75g of the microspherical maleic anhydride copolymer modified in Example 1, and then extruded and granulated in a twin-screw extruder. The crystallinity of the resulting PET-5 composition was analyzed by DSC.

[0084] Example 7:

[0085] 500g of PET (Yizheng Chemical Fiber, BG85) was blended with 2.5g of the microspherical maleic anhydride copolymer modified in Example 1, and then extruded and granulated in a twin-screw extruder. The crystallinity of the resulting PET-6 composition was analyzed by DSC.

[0086] Table 1 Crystallization properties of PET compositions

[0087] sample Crystallization temperature / ℃ Crystallization half-width at half maximum (FWHM) / °C Cold crystallization temperature / ℃ PET-1 203.80 6.74 none PET-2 175.04 18.28 131.81 PET-3 189.96 14.41 none PET-4 188.57 14.66 none PET-5 191.73 13.81 none PET-6 209.43 6.04 none

[0088] As can be seen from the data of PET-1, PET-2, and PET-3 in Table 1, compared with pure PET, the microspherical maleic anhydride copolymer modified by this invention has a nucleation effect on PET. In the preparation of compositions PET-3 and PET-4, visible particles of the maleic anhydride copolymer modified by the maleic anhydride copolymer can be seen in PET during the melt granulation process. Although it also has a nucleation effect on PET, there is still a gap compared with the crystallization data of PET-1. As can be seen from the data of PET-1 and PET-4, the maleic anhydride copolymer modified by cross-linked microspheres obtained by centrifugal drying has a worse nucleation effect on PET than the microspherical maleic anhydride copolymer modified by this application, indicating that the microspherical maleic anhydride copolymer modified by this invention has a greater advantage in improving the crystallization of PET. Furthermore, data from PET-1, PET-5, and PET-6 show that as the content of the microspherical maleic anhydride copolymer modifier prepared in this invention increases, the crystallization temperature of the PET composition gradually increases and the half-width and height of the crystals gradually decrease. This also indicates that the microspherical maleic anhydride copolymer modifier prepared in this invention has a significant nucleation effect on PET.

Claims

1. A microsphere-shaped maleic anhydride copolymer modifier, which is obtained by combining alkali metal ions after ring opening of the anhydride of the maleic anhydride copolymer, wherein the weight fraction of alkali metal ions in the microsphere-shaped maleic anhydride copolymer modifier is 1%-22%, preferably 2%-20%. The maleic anhydride copolymer is a linear maleic anhydride copolymer; The morphology of the microspherical maleic anhydride copolymer modified product is spherical or near-spherical, and preferably the average particle size of the microspherical maleic anhydride copolymer modified product is 2-15 μm, more preferably 4-12 μm.

2. The microspherical maleic anhydride copolymer modified according to claim 1, characterized in that: The maleic anhydride copolymer is at least one of maleic anhydride linear alternating copolymers, preferably a maleic anhydride linear alternating copolymer obtained by combining structural unit A provided by maleic anhydride and structural unit B provided by monomer M; the monomer M is selected from monomers containing isolated carbon-carbon double bonds; the monomer M is preferably at least one of vinyl acetate, C4 olefin, C4 fraction, C5 olefin, C5 fraction, C8 olefin, C8 fraction, C9 olefin, and C9 fraction, more preferably at least one of vinyl acetate, styrene, α-methylstyrene, C4 olefin, C4 fraction, C5 olefin, and C5 fraction.

3. The microspherical maleic anhydride copolymer modified according to claim 1, characterized in that: The number-average molecular weight of the maleic anhydride copolymer is less than 30,000 g / mol, preferably less than 25,000 g / mol.

4. The method for preparing the microspherical maleic anhydride copolymer modified according to any one of claims 1 to 3, characterized in that... Includes the following steps: The maleic anhydride copolymer was mixed and reacted with an aqueous solution of an alkali metal inorganic salt, and then dried by spray drying to obtain the microspherical maleic anhydride copolymer modified product.

5. The method for preparing the microspherical maleic anhydride copolymer modified according to claim 4, characterized in that... Includes the following steps: (a) Preparation of aqueous solutions of alkali metal inorganic salts; (b) The maleic anhydride copolymer is added to the aqueous solution of the alkali metal inorganic salt from step (a), and the reaction is carried out to form a solution; (c) The solution obtained in step (b) is spray-dried, and the powder is collected to obtain the microspherical maleic anhydride copolymer modified product.

6. The method for preparing the microspherical maleic anhydride copolymer modified according to claim 5, characterized in that: In step (a), The alkali metal inorganic salt may be selected from at least one of alkali metal hydroxides, alkali metal carbonates, alkali metal bicarbonates, alkali metal sulfates, and alkali metal nitrates, preferably at least one of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates, and more preferably at least one of alkali metal hydroxides.

7. The method for preparing the microspherical maleic anhydride copolymer modified according to claim 5, characterized in that: In step (b), The maleic anhydride copolymer is a linear maleic anhydride copolymer, preferably at least one of linear alternating maleic anhydride copolymers, and more preferably a linear alternating maleic anhydride copolymer obtained by combining structural unit A provided by maleic anhydride and structural unit B provided by monomer M; the monomer M is selected from monomers containing isolated carbon-carbon double bonds, preferably at least one of vinyl acetate, C4 olefin, C4 fraction, C5 olefin, C5 fraction, C8 olefin, C8 fraction, C9 olefin, and C9 fraction, and more preferably at least one of vinyl acetate, styrene, α-methylstyrene, C4 olefin, C4 fraction, C5 olefin, and C5 fraction.

8. The method for preparing the microspherical maleic anhydride copolymer modified according to claim 5, characterized in that: The molar ratio of the maleic anhydride copolymer (calculated by anhydride groups) to the alkali metal inorganic salt (calculated by alkali metal elements) is 1:(0.1-4), preferably 1:(0.2-3), and more preferably 1:(0.5-2.5).

9. The method for preparing the microspherical maleic anhydride copolymer modified according to claim 5, characterized in that: In step (b) described above, The amount of the maleic anhydride copolymer used is 0.1%-15% of the weight of the solution obtained in step (b), preferably 0.1%-10%.

10. The method for preparing the microspherical maleic anhydride copolymer modified according to claim 5, characterized in that: In step (b) described above, The number-average molecular weight of the maleic anhydride copolymer is less than 30,000 g / mol, preferably less than 25,000 g / mol.

11. The method for preparing the microspherical maleic anhydride copolymer modified according to claim 5, characterized in that: The viscosity of the solution obtained in step (b) is less than 100 mPa·s, preferably less than 80 mPa·s.

12. The method for preparing the microspherical maleic anhydride copolymer modified according to claim 5, characterized in that: The spray drying inlet air temperature is 150℃-200℃, preferably 155℃-180℃; the outlet air temperature is 60℃-100℃, preferably 70-95℃.

13. The microspherical maleic anhydride copolymer modified product prepared by the method of any one of claims 4 to 12.

14. Application of the microspherical maleic anhydride copolymer modified according to any one of claims 1 to 3 or the microspherical maleic anhydride copolymer modified according to claim 13, preferably in PET.

15. A PET composition, characterized in that... Contains PET and microsphere maleic anhydride copolymer modified; Preferably, the weight ratio of PET to the microsphere maleic anhydride copolymer is 100:(0.1-10), more preferably 100:(0.1-5); The microspherical maleic anhydride copolymer modified as described in any one of claims 1 to 3, 13.

Images