A high-fill masterbatch and its preparation method

Abstract

The present invention discloses a highly filled masterbatch and a preparation method thereof, belonging to the technical field of polymer materials. The highly filled masterbatch of the present invention has a filling amount of up to more than 70 wt%, and by limiting the particle size of the filler and the specific type of polyester in the masterbatch, the problem of die lip buildup during film blowing can be significantly suppressed, and the film breakage rate during film blowing is low; at the same time, the product has biodegradability and high environmental friendliness.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a high-filled masterbatch and a preparation method thereof. Background Art

[0002] In the field of plastic films, in order to improve the mechanical properties of products, it is often necessary to introduce a certain amount of inorganic fillers into the matrix polyester. However, due to differences in morphology and chemical properties, plastics containing inorganic fillers often have problems of component dispersibility and compatibility. To solve the above problems, the inorganic fillers are first prepared into masterbatches, then introduced into the matrix polyester, and finally blown into films to produce products.

[0003] With the high-efficiency requirements of the film blowing process, masterbatches with high filler content have begun to be mass-produced. Compared with the existing masterbatches with low filler content, such masterbatches have a smaller addition amount during film blowing batching, and a larger adjustable range of batching. People can add other functional additives in addition to the masterbatch and matrix polyester without worrying about the dispersibility problems caused by excessive addition of fillers. However, masterbatches with high filler content often accumulate materials at the die mouth during the film blowing process, and even film breakage may occur. Therefore, some additives are introduced in the prior art for improvement. For example, in some technologies, specific lubricants are introduced to extend the cycle of material accumulation at the die mouth, but this method has little effect on products with high filler content (especially when the filler content reaches more than 70 wt%), and it is necessary to target certain specific masterbatch polyesters; in other technologies, fluorine-containing additives are introduced to inhibit the generation of accumulated materials, but such additives have a great impact on the environment and do not meet the environmental protection requirements. Summary of the Invention

[0004] Based on the defects existing in the prior art, the purpose of the present invention is to provide a high-filled masterbatch. When the filler content is high, by limiting the particle size of the filler and the specific type of masterbatch polyester, the problem of material accumulation at the die mouth during the application of the product in film blowing can be greatly inhibited without adding fluorine-containing additives, and the film breakage rate during film blowing is low; at the same time, the product has biodegradability and high environmental protection.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A high-filled masterbatch, comprising the following components in parts by weight:

[0007] 60 - 90 parts of inorganic filler and 10 - 35 parts of biodegradable polyester;

[0008] The terminal carboxyl concentration of the biodegradable polyester is 18 - 32 mol / t, and the shear viscosity is 750 - 1150 Pa·s at a shear rate of 180 °C and 100 s -1 ;

[0009] The particle size D of the inorganic filler50 ≥3μm.

[0010] Preferably, the terminal carboxyl concentration of the degradable polyester is in the range of one or any two of 18 mol / t, 20 mol / t, 22 mol / t, 25 mol / t, mol / t, 28 mol / t, 30 mol / t, 32 mol / t; at 180°C, 100s -1 At a shear rate of , the shear viscosity is in the range of one or any two of 750 Pa*s, 800 Pa*s, 850 Pa*s, 900 Pa*s, 950 Pa*s, 1000 Pa*s, 1100 Pa*s, 1150 Pa*s.

[0011] Preferably, the mass content of the inorganic filler in the highly filled masterbatch is ≥ 60wt%.

[0012] Preferably, the highly filled masterbatch comprises the following components in parts by weight:

[0013] 70-85 parts of inorganic filler and 14-30 parts of degradable polyester.

[0014] More preferably, the weight proportion of the inorganic filler is one of 70 parts, 75 parts, 80 parts, 85 parts or any two of the range values, and the weight proportion of the degradable polyester is one of 14 parts, 15 parts, 18 parts, 20 parts, 24 parts, 25 parts, 30 parts or any two of the range values.

[0015] In the prior art, most inorganic fillers use difficult-to-degrade plastics such as polypropylene as the base polyester for preparing masterbatches. After compounding certain compatibilizers and lubricants, these polyesters can significantly improve the compatibility, dispersibility and bonding with inorganic fillers. However, such products are difficult to degrade and do not conform to the concept of environmental protection. At the same time, blown film products are mostly used in the food field, and some compatibilizers or lubricants used in non-food fields cannot be used (for example, polyethylene wax, which is often used in polyethylene packaging films, has excellent lubricating effects, but cannot be used in the food field). At the same time, when the filling amount of the masterbatch product is too large, it is difficult to suppress the generation of die buildup when these existing masterbatch systems are used in the blown film process. In the technical solution of the present invention, the highly filled masterbatch uses a degradable polyester as the base polyester, which is highly environmentally friendly and non-toxic, and can be used in the food field. At the same time, by limiting the end carboxyl concentration and shear viscosity of the polyester, and limiting the particle size D of the inorganic filler. 50 The lower limit can ensure that the components can maintain good filler dispersion and fluidity even when the filling amount is as high as 70wt% or more after mixing, the probability of die buildup during film blowing is significantly reduced, and the film formation continuity is high; on the other hand, the high-filling masterbatch does not contain any fluorine-containing components and will not affect the environment.

[0016] Since the product is mixed with pure polyester during the blown film batching, the degradable polyester in the product not only needs to have good compatibility and dispersibility with the inorganic filler, but also needs to establish good chemical connectivity with the pure polyester during batching to ensure that there is no die lip buildup during the blown film process. If the terminal carboxyl group concentration of the degradable polyester is too low or too high, it is difficult to achieve its compatibility and tight connection with the pure polyester and the inorganic filler. If the shear viscosity of the degradable polyester is too low or too high, or the size of the high-content inorganic filler is too small, it will cause the masterbatch product to not obtain ideal filler dispersibility during the production process, and the probability of die lip buildup during subsequent application will increase significantly.

[0017] In the high-fill masterbatch of the present invention, the test method for the terminal carboxyl group concentration of the degradable polyester is as follows: using a mixed solution of o-cresol and chloroform with a mass ratio of 7:3 as the solvent, and using an automatic potentiometric titrator to test the terminal carboxyl group value of the degradable polyester in the product. The test method refers to FZ / T 50012-2006 "Determination of Terminal Carboxyl Group Content in Polyester - Titration Analysis Method".

[0018] In the high-fill masterbatch of the present invention, the test method for the shear viscosity of the degradable polyester is as follows: referring to GB / T25278-2010 "Determination of the Flowability of Plastics by Capillary and Slit Die Rheometers for Plastics", directly test using a capillary rheometer. The model of the capillary rheometer is Dynisco LCR7000, the inner diameter of the die is 1mm, and the length is 40mm.

[0019] Preferably, the mass content of the inorganic filler in the high-fill masterbatch is 70-85wt%.

[0020] Preferably, the particle size D of the inorganic filler 50 is 3-5μm.

[0021] The test method for the particle size of the inorganic filler D50 is as follows: Place the product in a muffle furnace for calcination, screen the relevant inorganic filler from the obtained ash, and then test it using the method of GB / T 19077.1 "Particle Size Analysis - Laser Diffraction Method".

[0022] According to the actual usage requirements, those skilled in the art can select inorganic fillers with different particle size dimensions to prepare the masterbatch. However, due to the limitations of the blown film process and blown film equipment in the prior art, products with a particle size D 50 of less than 5μm are the most suitable.

[0023] More preferably, the inorganic filler is at least one of calcium carbonate, talc, diatomite, wollastonite, kaolin, and mica powder.

[0024] Preferably, the intrinsic viscosity of the biodegradable polyester at 25 °C is 1.19 to 1.36 dL / g.

[0025] Preferably, the intrinsic viscosity of the biodegradable polyester at 25 °C is one of 1.19 dL / g, 1.2 dL / g, 1.24 dL / g, 1.3 dL / g, 1.33 dL / g, 1.35 dL / g, 1.36 dL / g or the range value of any two of them.

[0026] More preferably, the intrinsic viscosity of the biodegradable polyester at 25 °C is 1.25 to 1.35 dL / g.

[0027] It is found by the inventors' tests that when there is more accumulation of materials at the die orifice, it will indeed cause film breakage. However, the frequency of film breakage is not only caused by the accumulation of materials at the die orifice. In the composition of the product, the viscosity of the biodegradable polyester has a certain influence on the continuity of the product during blown film. When the intrinsic viscosity of the biodegradable polyester meets the above range, the continuity of the product during blown film is higher.

[0028] Preferably, the biodegradable polyester is an aliphatic-aromatic copolyester.

[0029] More preferably, the biodegradable polyester is at least one of poly(butylene adipate-co-terephthalate), poly(butylene sebacate-co-terephthalate), poly(butylene azelate-co-terephthalate), poly(butylene succinate-co-terephthalate).

[0030] More preferably, in the aliphatic-aromatic copolyester, the molar ratio of the aliphatic polyester to the aromatic polyester is (4 to 6):(4 to 6).

[0031] More preferably, the preparation method of the aliphatic-aromatic copolymer is as follows:

[0032] React the aromatic dicarboxylic acid and diol in the presence of a catalyst at 220 to 260 °C and 35 to 45 kPa for 2 to 3 h to obtain an aromatic esterified product; react the aliphatic dicarboxylic acid and diol in the presence of a catalyst at 190 to 240 °C and 35 to 45 kPa for 2 to 3 h to obtain an aliphatic esterified product. Subsequently, react the aliphatic esterified product and the aromatic esterified product at 200 to 260 °C and 3.5 to 4.5 kPa for 1 to 1.25 h to obtain a prepolymer, and then react the prepolymer at 200 to 260 °C and 100 to 150 Pa for 1 to 1.25 h to obtain the aliphatic-aromatic copolymer.

[0033] In addition, it should be noted that the aliphatic-aromatic copolyester described in the present invention can be prepared by the above method, but it is not limited thereto. Those skilled in the art can also prepare it by other methods according to the actual situation, or obtain it by purchasing commercially available products, as long as the technical effects of the product are not affected.

[0034] The above-mentioned biodegradable polyesters have a high degradation rate, are safe and non-toxic, and are very suitable for the preparation of food packaging films with high requirements for safety and environmental protection.

[0035] Preferably, the components of the high-fill masterbatch further include 0.1 to 5 parts of processing aids;

[0036] More preferably, the processing aids are at least one of an antiblocking agent and a lubricant.

[0037] More preferably, the lubricant is at least one of stearic acid and stearate, and the antiblocking agent is at least one of oleic acid amide and inorganic silicon powder.

[0038] More preferably, the weight of the lubricant is 0.05 to 3 parts, and the weight of the antiblocking agent is 0.05 to 3 parts.

[0039] It should be noted that in the components of the high-fill masterbatch of the present invention, without compromising the effects of the product, some other functional components can be further introduced according to actual needs. For example, in order to impart color to the high-fill masterbatch, 0.01 to 1 part of common types of pigments can be introduced into the components, and the pigments can be organic pigments and / or inorganic pigments; in order to improve the environmental stability of the high-fill masterbatch, 0.01 to 1 part of common types of antioxidants can be introduced into the components, and the antioxidants can be at least one of hindered phenol antioxidants, hindered amine antioxidants, and phosphite antioxidants. Those skilled in the art should know that the teachings of the technical solutions of the present invention do not exclude the selection of components of the product.

[0040] Another object of the present invention is to provide a method for preparing the high-fill masterbatch, including the following steps:

[0041] Mix the components of the high-fill masterbatch evenly, and then melt and extrude and pelletize them in a twin-screw extruder to obtain the high-fill masterbatch.

[0042] The preparation method of the high-fill masterbatch of the present invention has simple operating steps, and there is no need to introduce special processes or equipment due to the high proportion of inorganic fillers, and industrial production can be realized.

[0043] Preferably, the temperature setting of the twin-screw extruder during melt extrusion is 140 to 240 °C.

[0044] Another object of the present invention is to provide a biodegradable polyester composition, including the following components in parts by weight:

[0045] 40 to 60 parts of biodegradable polyester and 40 to 60 parts of the high-fill masterbatch of the present invention.

[0046] Based on its high inorganic filler content and non-toxic and biodegradable properties, the high-filled masterbatch of the present invention can be directly applied and used in combination with various biodegradable matrix polyesters for production, with high production continuity and good product quality.

[0047] Preferably, the biodegradable polyester includes at least one of polybutylene terephthalate adipate, polybutylene terephthalate sebacate, polybutylene terephthalate azelate, and polybutylene terephthalate succinate.

[0048] More preferably, the type of the biodegradable polyester in the biodegradable polyester composition of the present invention can be the same as that of the biodegradable polyester in the high-filled masterbatch of the present invention.

[0049] Another object of the present invention is to provide the application of the biodegradable polyester composition in the preparation of plastic films.

[0050] The beneficial effects of the present invention are as follows: The present invention provides a high-filled masterbatch. By limiting the particle size of the filler and the specific type of the masterbatch polyester, the problem of die lip buildup during the application of the product in blown film can be greatly inhibited without adding fluorine-containing additives, and the film breakage rate during blown film is low; at the same time, the product has biodegradability and high environmental friendliness. Detailed Embodiments

[0051] In order to better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific examples and comparative examples. The purpose is to understand the content of the present invention in detail, rather than to limit the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention. The experimental reagents and instruments involved in the implementation of the present invention are all common ordinary reagents and instruments unless otherwise specified.

[0052] Examples 1 to 10

[0053] Examples of the high-filled masterbatch of the present invention, and the component composition of the high-filled masterbatch is shown in Table 1.

[0054] The preparation method of the product includes the following steps:

[0055] Mix the components of the fluorine-free high-filled masterbatch evenly, and then place them in a twin-screw extruder for melt extrusion and pelletization at 140-240 °C to obtain the fluorine-free high-filled masterbatch.

[0056] Comparative Examples 1 to 5

[0057] The difference between each comparative example and the example lies only in the component types and ratios, as shown in Table 2.

[0058] Among the components of each example and comparative example,

[0059] Degradable polyester 1: PBAT polyester, self-made PBAT-1, with a terminal carboxyl concentration of 22 mol / t, at 180 °C and 100 s -1 under a shear rate of, the shear viscosity is 900 Pa·s, and the intrinsic viscosity at 25 °C is 1.3 dL / g;

[0060] The preparation method is as follows:

[0061] 1) Add terephthalic acid and 1,4-butanediol to the esterification reactor according to a molar ratio of 1:1.5, and add 1% of the total mass of the raw materials, n-butyl titanate as a catalyst, and react at a temperature of 230 °C and a pressure of 40 KPa for 2.5 h to obtain esterified product A1;

[0062] 2) Add adipic acid and 1,4-butanediol to the esterification reactor according to a molar ratio of 1:1.67, and react at a temperature of 200 °C and a pressure of 40 KPa for 2.5 h to obtain esterified product A2;

[0063] 3) Continuously feed the two esterified products A1 and A2 into the mixer according to a molar ratio of 1:1 to mix, and react at a temperature of 240 °C and a pressure of 4 KPa for 2.5 h to obtain a prepolymer, and then continue to polymerize at a temperature of 240 °C and a pressure of 120 Pa for 2 h to obtain biodegradable poly(butylene adipate-co-terephthalate) PBAT-1.

[0064] Degradable polyester 2: PBSeT polyester, self-made with a terminal carboxyl concentration of 25 mol / t, at 180 °C and 100 s -1 under a shear rate of, the shear viscosity is 1000 Pa·s, and the intrinsic viscosity at 25 °C is 1.33 dL / g;

[0065] The preparation method is as follows:

[0066] 1) Add terephthalic acid and 1,4-butanediol to the esterification reactor according to a molar ratio of 1:1.5, and add 1% of the total mass of the raw materials, n-butyl titanate as a catalyst, and react at a temperature of 240 °C and a pressure of 40 KPa for 2.5 h to obtain esterified product A1;

[0067] 2) Add sebacic acid and 1,4-butanediol to the esterification reactor according to a molar ratio of 1:1.67, and react at a temperature of 200 °C and a pressure of 40 KPa for 2.5 h to obtain esterified product A2;

[0068] 3) Feed the two esterified products A1 and A2 into a mixer continuously according to a molar ratio of 1:1 to calculate the feed liquid flow rate, react for 2.5 h under the conditions of a temperature of 240 °C and a pressure of 4 KPa to obtain a prepolymer, and then continue to polymerize for 2.5 h under the conditions of a temperature of 240 °C and a pressure of 120 Pa to obtain biodegradable poly(butylene sebacate / terephthalate) PBSeT.

[0069] Degradable polyester 3: PBAT polyester, self-made PBAT-2, with a terminal carboxyl group concentration of 20 mol / t, at 180 °C, 100 s -1 Under a shear rate of, the shear viscosity is 1100 Pa·s, and the intrinsic viscosity at 25 °C is 1.35 dL / g;

[0070] The preparation method is as follows:

[0071] 1) Add terephthalic acid and 1,4-butanediol to an esterification reactor according to a molar ratio of 1:1.5, and add 1% of the total mass of the raw materials of n-butyl titanate as a catalyst. React for 2.5 h under the conditions of a temperature of 240 °C and a pressure of 40 KPa to obtain an esterified product A1;

[0072] 2) Add adipic acid and 1,4-butanediol to an esterification reactor according to a molar ratio of 1:1.67, and react for 2.5 h under the conditions of a temperature of 200 °C and a pressure of 40 KPa to obtain an esterified product A2;

[0073] 3) Feed the two esterified products A1 and A2 into a mixer continuously according to a molar ratio of 1:1 to calculate the feed liquid flow rate, react for 2.5 h under the conditions of a temperature of 240 °C and a pressure of 4 KPa to obtain a prepolymer, and then continue to polymerize for 2.5 h under the conditions of a temperature of 240 °C and a pressure of 120 Pa to obtain biodegradable poly(butylene adipate / terephthalate) PBAT-2.

[0074] Degradable polyester 4: PBAT polyester, self-made PBAT-3, with a terminal carboxyl group concentration of 30 mol / t, at 180 °C, 100 s -1 Under a shear rate of, the shear viscosity is 800 Pa·s, and the intrinsic viscosity at 25 °C is 1.25 dL / g;

[0075] The preparation method is as follows:

[0076] 1) Add terephthalic acid and 1,4-butanediol to an esterification reactor according to a molar ratio of 1:1.5, and add 1% of the total mass of the raw materials of n-butyl titanate as a catalyst. React for 2.5 h under the conditions of a temperature of 240 °C and a pressure of 40 KPa to obtain an esterified product A1;

[0077] 2) Add adipic acid and 1,4-butanediol to the esterification reactor according to a molar ratio of 1:1.67, and react for 2.5 h under the conditions of a temperature of 200 °C and a pressure of 40 KPa to obtain esterified product A2;

[0078] 3) Continuously feed the two esterified products A1 and A2 into the mixer for mixing according to a molar ratio of 1:1, and react for 2.0 h under the conditions of a temperature of 260 °C and a pressure of 4 KPa to obtain a prepolymer, and then continue to polymerize for 2.0 h under the conditions of a temperature of 260 °C and a pressure of 120 Pa to obtain biodegradable poly(butylene adipate-co-terephthalate) PBAT-3.

[0079] Degradable polyester 5: PBAT polyester, self-made PBAT-4, with a terminal carboxyl group concentration of 25 mol / t, at a shear rate of 180 °C and 100 s -1 The shear viscosity is 850 Pa·s, and the intrinsic viscosity at 25 °C is 1.24 dL / g;

[0080] The preparation method is as follows:

[0081] 1) Add terephthalic acid and 1,4-butanediol to the esterification reactor according to a molar ratio of 1:1.5, and add 1% of the total mass of the raw materials of tetrabutyl titanate as a catalyst, and react for 2.5 h under the conditions of a temperature of 240 °C and a pressure of 40 KPa to obtain esterified product A1;

[0082] 2) Add adipic acid and 1,4-butanediol to the esterification reactor according to a molar ratio of 1:1.67, and react for 2.5 h under the conditions of a temperature of 200 °C and a pressure of 40 KPa to obtain esterified product A2;

[0083] 3) Continuously feed the two esterified products A1 and A2 into the mixer for mixing according to a molar ratio of 1:1, and react for 1.0 h under the conditions of a temperature of 220 °C and a pressure of 4 KPa to obtain a prepolymer, and then continue to polymerize for 1.0 h under the conditions of a temperature of 220 °C and a pressure of 120 Pa to obtain biodegradable poly(butylene adipate-co-terephthalate) PBAT-4.

[0084] Degradable polyester 6: PBAT polyester, self-made PBAT-5, with a terminal carboxyl group concentration of 28 mol / t, at a shear rate of 180 °C and 100 s -1 The shear viscosity is 950 Pa·s, and the intrinsic viscosity at 25 °C is 1.2 dL / g;

[0085] The preparation method is as follows:

[0086] 1) Add terephthalic acid and 1,4-butanediol into the esterification reactor according to a molar ratio of 1:1.5, and add n-butyl titanate as a catalyst accounting for 1% of the total mass of the raw materials. React for 2.5 h under the conditions of a temperature of 240 °C and a pressure of 40 KPa to obtain esterified product A1;

[0087] 2) Add adipic acid and 1,4-butanediol into the esterification reactor according to a molar ratio of 1:1.67. React for 2.5 h under the conditions of a temperature of 200 °C and a pressure of 40 KPa to obtain esterified product A2;

[0088] 3) Continuously feed the two esterified products A1 and A2 into the mixer according to a molar ratio of 1:1 to calculate the feed liquid flow rate and mix them. React for 1.5 h under the conditions of a temperature of 240 °C and a pressure of 4 KPa to obtain a prepolymer, and then continue to polymerize for 1.5 h under the conditions of a temperature of 240 °C and a pressure of 120 Pa to obtain biodegradable poly(butylene adipate-co-terephthalate) PBAT-5.

[0089] Degradable polyester 7: PBAT polyester, self-made PBAT-6, with a terminal carboxyl group concentration of 40 mol / t, at a shear rate of 180 °C and 100 s -1 The shear viscosity is 600 Pa·s, and the intrinsic viscosity at 25 °C is 1.15 dL / g;

[0090] The preparation method is as follows:

[0091] 1) Add terephthalic acid and 1,4-butanediol into the esterification reactor according to a molar ratio of 1:1.5, and add n-butyl titanate as a catalyst accounting for 1% of the total mass of the raw materials. React for 2 h under the conditions of a temperature of 280 °C and a pressure of 40 KPa to obtain esterified product A1;

[0092] 2) Add adipic acid and 1,4-butanediol into the esterification reactor according to a molar ratio of 1:1.67. React for 2.5 h under the conditions of a temperature of 260 °C and a pressure of 40 KPa to obtain esterified product A2;

[0093] 3) Continuously feed the two esterified products A1 and A2 into the mixer according to a molar ratio of 1:1 to calculate the feed liquid flow rate and mix them. React for 1.5 h under the conditions of a temperature of 240 °C and a pressure of 4 KPa to obtain a prepolymer, and then continue to polymerize for 1.5 h under the conditions of a temperature of 240 °C and a pressure of 120 Pa to obtain biodegradable poly(butylene adipate-co-terephthalate) PBAT-6.

[0094] Degradable polyester 8: PBAT polyester, self-made PBAT-7, with a terminal carboxyl group concentration of 15 mol / t, at a shear rate of 180 °C and 100 s -1 The shear viscosity is 1200 Pa·s, and the intrinsic viscosity at 25 °C is 1.4 dL / g;

[0095] The preparation method is as follows:

[0096] 1) Add terephthalic acid and 1,4-butanediol into the esterification reactor according to a molar ratio of 1:1.5, and add 1% of the total mass of the raw materials, n-butyl titanate as the catalyst. React for 3 h at a temperature of 220 °C and a pressure of 40 KPa to obtain the esterified product A1;

[0097] 2) Add adipic acid and 1,4-butanediol into the esterification reactor according to a molar ratio of 1:1.67. React for 3 h at a temperature of 220 °C and a pressure of 40 KPa to obtain the esterified product A2;

[0098] 3) Continuously feed the two esterified products A1 and A2 into the mixer according to a molar ratio of 1:1 to calculate the feed liquid flow rate and mix them. React for 3.5 h at a temperature of 220 °C and a pressure of 4 KPa to obtain the prepolymer, and then continue to polymerize for 3.5 h at a temperature of 220 °C and a pressure of 120 Pa to obtain the biodegradable poly(butylene adipate-co-terephthalate) PBAT-7.

[0099] Degradable polyester 9: PBAT polyester, self-made PBAT-8, with a terminal carboxyl group concentration of 55 mol / t, at a shear rate of 180 °C and 100 s -1 the shear viscosity is 1050 Pa·s, and the intrinsic viscosity at 25 °C is 1.30 dL / g;

[0100] The preparation method is as follows:

[0101] 1) Add terephthalic acid and 1,4-butanediol into the esterification reactor according to a molar ratio of 1:1.5, and add 1% of the total mass of the raw materials, n-butyl titanate as the catalyst. React for 2.5 h at a temperature of 300 °C and a pressure of 40 KPa to obtain the esterified product A1;

[0102] 2) Add adipic acid and 1,4-butanediol into the esterification reactor according to a molar ratio of 1:1.67. React for 2.5 h at a temperature of 280 °C and a pressure of 40 KPa to obtain the esterified product A2;

[0103] 3) Continuously feed the two esterified products A1 and A2 into the mixer according to a molar ratio of 1:1 to calculate the feed liquid flow rate and mix them. React for 2.5 h at a temperature of 280 °C and a pressure of 4 KPa to obtain the prepolymer, and then continue to polymerize for 2.5 h at a temperature of 280 °C and a pressure of 120 Pa to obtain the biodegradable poly(butylene adipate-co-terephthalate) PBAT-8.

[0104] Degradable polyester 10: PBAT polyester, self-made PBAT-9, with a terminal carboxyl group concentration of 25 mol / t, at 180 °C and 100 s-1 At a shear rate of, the shear viscosity is 1300 Pa·s, and the intrinsic viscosity at 25 °C is 1.33 dL / g;

[0105] The preparation method is as follows:

[0106] 1) Add terephthalic acid and 1,4-butanediol in a molar ratio of 1:1.5 to an esterification reactor, and add 1% of the total mass of the raw materials, n-butyl titanate as a catalyst. React at a temperature of 240 °C and a pressure of 40 KPa for 2.5 h to obtain esterified product A1;

[0107] 2) Add adipic acid and 1,4-butanediol in a molar ratio of 1:1.67 to an esterification reactor, and react at a temperature of 200 °C and a pressure of 40 KPa for 2.5 h to obtain esterified product A2;

[0108] 3) Continuously feed the two esterified products A1 and A2 into a mixer according to a molar ratio of 1:1 to mix, and react at a temperature of 260 °C and a pressure of 4 KPa for 3 h to obtain a prepolymer, and then continue to polymerize at a temperature of 260 °C and a pressure of 120 Pa for 3 h to obtain biodegradable poly(butylene adipate-co-terephthalate) PBAT-9.

[0109] Inorganic filler 1: Calcium carbonate, obtained by screening the ACC-818 product produced by Lianzhou Xinrong;

[0110] Inorganic filler 2: Talc powder, the SK-6500P product produced by Liaoning Jinghua New Materials Co., Ltd., with a particle size D 50 being 4.5 μm;

[0111] Inorganic filler 3: Calcium carbonate, obtained by screening the ACC-818 product produced by Lianzhou Xinrong;

[0112] Inorganic filler 4: Calcium carbonate, obtained by screening the ACC-818 product produced by Lianzhou Xinrong;

[0113] Inorganic filler 5: Calcium carbonate, obtained by screening the ACC-818 product produced by Lianzhou Xinrong;

[0114] Processing aid: A mixture obtained by compounding commercially available opening agent oleic acid amide and commercially available lubricant stearic acid in a mass ratio of 1:1;

[0115] Zinc stearate: Commercially available; Unless otherwise specified, the component raw materials used in each example and comparative example of the present invention are all commercially available raw materials, and the component raw materials used in each parallel experiment are the same.

[0116] Table 1

[0117]

[0118] Table 2

[0119]

[0120]

[0121] Effect Example 1

[0122] In order to verify the performance of the products of the present invention, the following performance tests were carried out on the products of each example and comparative example. The specific steps are as follows:

[0123] The products of each example and comparative example were compounded with PBAT (model KB100) produced by Jinfa Biology in a mass ratio of 1:1 and blown into films using a single-screw extrusion blow molding machine with a diameter of 50 mm, a die diameter of 75 mm, a set temperature of 135 °C, an extrusion frequency of 16 HZ for the extruder, a traction of 22 HZ, a film thickness of 0.03 mm, and a film width of 385 mm. Continuous film blowing was carried out for 6 h. The situation of material accumulation at the die opening was observed, the mass of the accumulated material at the die opening was collected and weighed, and the accumulation level was statistically analyzed:

[0124] Level 1: 0 - 0.5 g;

[0125] Level 2: 0.5 - 1 g;

[0126] Level 3: 1 - 2 g;

[0127] Level 4: 2 - 5 g;

[0128] Level 5: Above 5 g.

[0129] Subsequently, the film breakage frequency during film blowing was statistically analyzed.

[0130] The test results are shown in Tables 3 and 4.

[0131] Table 3

[0132]

[0133] Table 4

[0134] Product performance Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Comparative example 6 Comparative example 7 Accumulated material level 4 4 4 5 5 5 5 Film breakage frequency (times / 6h) 3 4 3 5 5 4 5

[0135] As can be seen from Tables 3 and 4, when the high-filled masterbatch described in each embodiment of the present invention is applied to blown film, obvious die lip build-up does not occur. The build-up levels of each product reach level 3 and below. At the same time, the film breakage frequency is less than 2 times / 6h, and the performance is excellent. In particular, for the products of Example 2, Example 4, Example 6, and Example 8, the inorganic filler filling amount reaches 85wt%, and good use performance can still be achieved. From the comparison of Example 1, Example 9, and Example 10, it can be seen that when the terminal carboxyl group concentration and shear viscosity of the biodegradable polyester in the product are maintained within the range defined in the present invention, and the intrinsic viscosity is maintained at 1.19 - 1.36 dL / g, the die lip build-up of the product is less, the continuity during blown film is higher, and the film breakage frequency is further reduced. In contrast, the particle size D of the inorganic filler in the product of Comparative Example 1 50 is too small, and it is difficult to achieve good dispersibility of the inorganic filler during the preparation of the masterbatch. Its die lip build-up level is high, and the film breakage frequency is high; the defined parameters of the biodegradable polyester used in the products of Comparative Examples 2 - 5 do not conform to the scope of the present invention's solution, so the products cannot maintain good performance. Based on Comparative Examples 2 and 3, in Comparative Examples 6 and 7, zinc stearate, a lubricant often used in the prior art to improve the die lip build-up problem of other types of masterbatches during blown film, is introduced, and the relevant performance of the products has not been significantly improved

[0136] Furthermore, according to the above method, KB100 is replaced with PBSeT (model A300) produced by Jinfa Biology, and then the products of Example 1, Comparative Example 2, and Comparative Example 3 are subjected to blown film treatment with the same process. The results are shown in Table 5. It can be seen that even when different types of matrix polyesters are selected for compounding and blown film, the high-filled masterbatch of the products described in the present invention still has the expected performance, while the products prepared with inappropriate biodegradable polyester still cannot solve the die lip build-up problem

[0137] Table 5

[0138] Product performance (A400) Example 2 Comparative example 2 Comparative example 3 Accumulated material level 1 4 4 Film breakage frequency (times / 6h) 0 4 4

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention

Claims

1. A highly filled masterbatch, characterized in that, it comprises the following components in parts by weight: 60 - 90 parts of inorganic filler and 10 - 35 parts of biodegradable polyester; The terminal carboxyl group concentration of the biodegradable polyester is 18 to 32 mol / t, and at a shear rate of -1 180 °C and 100 s, the shear viscosity is 750 to 1150 Pa·s, and the intrinsic viscosity at 25 °C is 1.19 to 1.36 dL / g; -1 ​ The particle size D of the inorganic filler 50 ≥ 3 μm.

2. The highly filled masterbatch according to claim 1, characterized in that, the components comprise the following components in parts by weight: 70 - 85 parts of inorganic filler and 15 - 30 parts of biodegradable polyester.

3. The highly filled masterbatch according to claim 1, characterized in that, The particle size D of the inorganic filler 50 is 3 to 5 μm.

4. The highly filled masterbatch according to claim 3, characterized in that, the inorganic filler is at least one of calcium carbonate, talcum powder, diatomaceous earth, wollastonite, kaolin, mica powder.

5. The highly filled masterbatch according to claim 1, characterized in that, the biodegradable polyester is at least one of polybutylene adipate terephthalate, polybutylene terephthalate sebacate, polybutylene terephthalate azelate, polybutylene terephthalate succinate.

6. The highly filled masterbatch according to claim 1, characterized in that, the components of the highly filled masterbatch further comprise 0.1 - 5 parts of processing aids.

7. The highly filled masterbatch according to claim 6, characterized in that, the processing aids are at least one of an antiblocking agent and a lubricant.

8. The preparation method of the highly filled masterbatch according to any one of claims 1 - 7, characterized in that, it comprises the following steps: Mix the components of the highly filled masterbatch evenly, and then place them into a twin - screw extruder for melt extrusion and pelletization to obtain the highly filled masterbatch.

9. A biodegradable polyester composition, characterized in that, it comprises the following components in parts by weight: 40 - 60 parts of biodegradable polyester and 40 - 60 parts of the highly filled masterbatch according to any one of claims 1 - 6.

10. The application of the biodegradable polyester composition according to claim 9 in the preparation of plastic films.

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