High-flowability transparent polypropylene composition, high-flowability transparent polypropylene material and preparation method of high-flowability transparent polypropylene material

Abstract

The invention provides a high-flowability transparent polypropylene composition, a high-flowability transparent polypropylene material and a preparation method of the high-flowability transparent polypropylene composition and the high-flowability transparent polypropylene material. The high-flowability transparent polypropylene composition comprises the following raw materials: polypropylene resin; the hindered amine stabilizer accounts for 0.005%-0.2% of the mass of the polypropylene resin; an antioxidant accounting for 0.05%-0.6% of the mass of the polypropylene resin; a deacidification agent accounting for 0.01%-0.2% of the mass of the polypropylene resin; the nucleating agent accounts for 0.03%-0.4% of the mass of the polypropylene resin; wherein the polypropylene resin is polypropylene random copolymer with a melt flow rate less than or equal to 60g / 10min. The polypropylene material with high flowability and high transparency is prepared by irradiating the polypropylene composition adopting a specific additive formula, and the melt strength of the polypropylene material is improved.

Description

Technical Field

[0001] The invention relates to the field of transparent polypropylene materials, and in particular to a high-flow transparent polypropylene composition, a high-flow transparent polypropylene material and a preparation method thereof. Background Art

[0002] Polypropylene resin has the advantages of good comprehensive physical and mechanical properties, non-toxicity, chemical corrosion resistance, easy processing, and low price, and is widely used in the fields of medicine and food packaging. At the same time, since polypropylene is a partially crystalline resin, under normal processing conditions, the crystallization speed is relatively slow, and it is easy to form larger spherulites, making it difficult for light to pass through the entire product. Therefore, the transparency and glossiness of the product are poor, and the appearance lacks aesthetics, which limits its application in the fields of packaging, medical devices, and household goods. Therefore, high-transparency polypropylene has been a hot spot in the development of polypropylene products in recent years, and the development speed of transparent polypropylene resin is 7-9% higher than that of ordinary polypropylene. For example, the random transparent polypropylene product RP340R developed by Lanzhou Petrochemical Company can be processed in a wide temperature range, with low temperature and high gloss. It can replace polystyrene (PS) in food packaging containers, and the product's melt flow rate (MFR), flexural modulus, impact strength and other indicators are better than similar products.

[0003] At present, high-flow transparent polypropylene is mainly produced in two ways, one of which is the degradation method. Domestically produced high-flow transparent random copolymer polypropylene (MFR ≥ 35g / 10min) mostly adopts this method, that is, first synthesize a base resin with a low melt flow rate, and then add rheological masterbatch to degrade in the granulation stage to improve the fluidity of the final product. The disadvantages of this method are: ① The need to add peroxide increases the production cost; ② Since the uniformity of peroxide addition is not easy to control, the product performance fluctuates greatly; ③ The residual peroxide will bring about adverse consequences such as odor and yellowing of the product. Therefore, the fluidity of the product produced by the degradation method is unstable, the odor is strong, it is easy to turn yellow, and the impact performance is poor. The final product is difficult to meet the requirements of food packaging materials. The other is to use a new catalyst system and an improved polymerization process to directly synthesize high-flow transparent polypropylene by adding hydrogen in a loop reactor, that is, the hydrogen adjustment method. At present, the hydrogen adjustment method is mainly used to prepare medium and low melt flow rate polypropylene, and is not used to prepare high melt flow rate polypropylene. This is because a large amount of hydrogen needs to be added to directly polymerize and produce high melt index polypropylene in a loop process polypropylene device, and the production process is difficult to control.

[0004] As market competition becomes increasingly fierce, the processing efficiency and energy consumption of large parts have become one of the important factors affecting the cost and profitability of downstream processing companies. In the application field of small-sized syringes, polypropylene raw materials are also required to have a high melt flow rate to meet product processing requirements.

[0005] At present, most domestic transparent polypropylene products have a low melt flow rate. Many polypropylene manufacturers are developing high melt index transparent polypropylene products. For example, Panjin Petrochemical, Zhongyuan Petrochemical, Lanzhou Petrochemical Company, etc. have successfully developed transparent polypropylene industrial products with a melt flow rate of 60g / 10min.

[0006] CN109776954A discloses a transparent polypropylene material composed of 100 parts of homopolymer polypropylene, 0.05-0.2 parts of nucleating agent, 0.04-0.3 parts of antioxidant, and 0.01-0.04 parts of organic peroxide, and a preparation method thereof. The homopolymer polypropylene is prepared by hydrogen adjustment, and high-flow polypropylene is produced by adding organic peroxide for degradation. The product is a homopolymer product with a high haze (over 30%).

[0007] CN104312013A discloses a method for producing a high-flow, high-impact transparent polypropylene material by hydrogen adjustment. The product has an ethylene content of 3.0-4.0% and a simple beam notched impact strength of 6.0-6.5 kJ / m 2 The melt flow rate of the product is 35-41g / 10min, and the haze can reach 9%.

[0008] Patent application No. CN 202010490437.3 discloses a method for increasing the melt index of polypropylene plastic particles by irradiation to obtain a polypropylene meltblown material with a melt index of about 1500.

[0009] Patent application No. CN202111359764.6 discloses a pre-irradiated grafted modified PP meltblown material and its preparation process, wherein the meltblown material includes the following components: 70-90 parts of polypropylene resin, 10-30 parts of ethylene-octene copolymer, 1-6 parts of grafted modifier, 12-18 parts of modified inorganic filler, 0.2-0.8 parts of foaming agent, 0.1-0.5 parts of nucleating agent, 1-3 parts of antioxidant, 0.02-0.05 parts of pore regulator, 0.1-0.5 parts of ultraviolet absorber, and 0.01-0.08 parts of light stabilizer.

[0010] Patent application No. CN202111359763.1 discloses an irradiated modified PP meltblown material composed of 100-110 parts of irradiated polypropylene, 10-20 parts of irradiated polyethylene, 0.1-0.5 parts of antioxidant, 0.02-0.06 parts of lubricant, 1-6 parts of ultraviolet light absorber, 0.1-0.5 parts of light stabilizer, and 0.01-0.1 parts of modified nano-silicon dioxide. The preparation method of irradiated polypropylene and irradiated polyethylene is as follows: irradiate polypropylene or polyethylene through an electron accelerator or a cobalt source, the irradiation dose is 2.5-4.5kGy, and the irradiation transmission speed is 3-8cm / s.

[0011] However, in the prior art, the high-flow polypropylene produced by the peroxide degradation method has a strong odor; the high-flow polypropylene produced by the hydrogen adjustment method has high requirements for polymerization equipment and processes due to the high amount of hydrogenation. Therefore, there is still a need for an effective method that can simply produce high-clean, high-flow polypropylene, so as to achieve the preparation of high-flow transparent polypropylene materials whose flowability can be adjusted as needed. Summary of the invention

[0012] In order to solve the above technical problems, the purpose of the present invention is to provide a high-flow transparent polypropylene composition, a high-flow transparent polypropylene material and a preparation method thereof. The polypropylene composition of the present invention can be irradiated to prepare a polypropylene material with high flow and high transparency, and its melt strength can be improved.

[0013] To achieve the above object, the present invention provides a high-flow transparent polypropylene composition, wherein the raw material composition of the high-flow transparent polypropylene composition comprises:

[0014] (A) polypropylene resin;

[0015] (B) 0.005% to 0.2% of a hindered amine stabilizer based on the mass of the polypropylene resin;

[0016] (C) 0.05% to 0.6% of an antioxidant based on the mass of the polypropylene resin;

[0017] (D) 0.01% to 0.2% of an acid scavenger based on the mass of the polypropylene resin; and

[0018] (E) 0.03% to 0.4% of a nucleating agent based on the mass of the polypropylene resin;

[0019] Wherein, the polypropylene resin is a random copolymer polypropylene with a melt flow rate less than or equal to 60g / 10min.

[0020] According to a specific embodiment of the present invention, preferably, the amount of the hindered amine stabilizer is 0.02%-0.1%.

[0021] According to a specific embodiment of the present invention, preferably, the amount of the antioxidant is 0.1%-0.5%.

[0022] According to a specific embodiment of the present invention, preferably, the amount of the acid scavenger is 0.03%-0.1%.

[0023] According to a specific embodiment of the present invention, preferably, the amount of the nucleating agent is 0.05%-0.3%.

[0024] According to a specific embodiment of the present invention, preferably, the random copolymer polypropylene is ethylene-propylene random copolymer polypropylene and / or propylene-butene random copolymer polypropylene.

[0025] In some specific embodiments, preferably, the ethylene content in the ethylene-propylene random copolymer polypropylene is 1-8 wt % and the melt flow rate is 5-40 g / 10 min.

[0026] In some specific embodiments, preferably, the propylene-butene random copolymer polypropylene has a butene content of 1-10 wt % and a melt flow rate of 8-50 g / 10 min.

[0027] According to a specific embodiment of the present invention, preferably, the random copolymer polypropylene is ethylene-propylene random copolymer polypropylene, the ethylene content of the ethylene-propylene random copolymer polypropylene is 2-5wt%, and the melt flow rate is 8-20g / 10min.

[0028] According to a specific embodiment of the present invention, preferably, the hindered amine stabilizer includes bis(2,2,6,6,-tetramethyl-4-piperidinyl) sebacate (GW-770, light stabilizer 770), bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate (GW-123, light stabilizer 123), 2,2,6,6-tetramethyl-4-piperidinyl stearate (GW-3853, light stabilizer 3853), poly{(6-morpholinyl-5-triazine-2,4-diyl)(2,2,6,6-tetramethylpiperidinyl)iminohexamethylene[(2,2,6,6-tetramethylpiperidinyl)-imino]} (GW-3346, light stabilizer 3346), poly{[6-[(1,1,3,3-tetramethylbutyl)amino]]-1,3,5-triazine-2 ,4-[(2,2,6,6,-tetramethyl-piperidinyl)imino]-1,6-hexanediamine[(2,2,6,6-tetramethyl-4-piperidinyl)imino]}(GW-944, Light Stabilizer 944), poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinethanol) succinate (GW-622, Light Stabilizer 622), high molecular weight triazine-piperidinyl condensate (GW-119, Light Stabilizer 119), polymer of the reaction product of N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine with 2,4,6-trichloro-1,3,5-triazine and N-butyl-1-butylamine and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine (GW-2020, Light Stabilizer 2020), structural unit containing -(TMPM) m1 -polymeric hindered amine stabilizer, structural unit comprising -(PMPM) m2- one or a combination of two or more of the polymerizable hindered amine stabilizers, etc.; wherein TMPM is a structural unit obtained by the polymerization reaction of 2,2,6,6-tetramethylpiperidinol-4-methylacrylate, and PMPM is a structural unit obtained by the polymerization reaction of 1,2,2,6,6-pentamethylpiperidinol-4-methylacrylate; m1 and m2 represent the degree of polymerization, and m1 and m2 are 4-100.

[0029] In some specific embodiments, preferably, the structural unit comprises -(TMPM) m1 -The polymeric hindered amine stabilizer is hexadecyl poly 2,2,6,6-tetramethylpiperidinol-4-methylacrylate; the structural unit comprises -(PMPM) m2 -The polymeric hindered amine stabilizer is poly 1,2,2,6,6-pentamethylpiperidinol-4-methacrylate.

[0030] In some specific embodiments, the polymerization reaction of TMPM or PMPM monomers can adopt various existing polymerization techniques.

[0031] According to a specific embodiment of the present invention, preferably, the antioxidant is a phenolic antioxidant, or a composite antioxidant of a phenolic antioxidant and other antioxidants.

[0032] In some specific embodiments, preferably, the other antioxidants include phosphite antioxidants and / or thioester antioxidants.

[0033] In some specific embodiments, preferably, in the composite antioxidant, the phenolic antioxidant is the main antioxidant, and the other antioxidants are auxiliary antioxidants.

[0034] In some specific embodiments, preferably, the mass ratio of the primary antioxidant to the secondary antioxidant is 1:1-1:3.

[0035] In some specific embodiments, preferably, the phenolic antioxidant includes one or a combination of two or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol (antioxidant 1010), 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (antioxidant 330), β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076), 4,4'-thiobis(6-tert-butyl-3-methylphenol) (antioxidant 300), etc.

[0036] In some specific embodiments, preferably, the other antioxidants include one or a combination of two or more of tris(2,4-di-tert-butylphenyl)phosphite (antioxidant 168), bis(2,4-di-tert-butylphenol)pentaerythritol diphosphite (antioxidant 626), thiodipropionate, etc.

[0037] In some specific embodiments, preferably, the composite antioxidant includes a mixture of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol (antioxidant 1010) and tris(2,4-di-tert-butylphenyl)phosphite (antioxidant 168), a mixture of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076) and bis(2,4-di-tert-butylphenol)pentaerythritol diphosphite (antioxidant 626), a mixture of 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (antioxidant 330) and thiodipropionate, or a combination of two or more thereof.

[0038] According to a specific embodiment of the present invention, preferably, the acid scavenger is calcium stearate and / or hydrotalcite.

[0039] According to a specific embodiment of the present invention, preferably, the nucleating agent includes one or a combination of two or more of sorbitol and phosphate.

[0040] In some specific embodiments, preferably, the sorbitol nucleating agent is millad 3988 and / or NX8000 (produced by Milliken & Company).

[0041] In some specific embodiments, preferably, the phosphate nucleating agent is one or a combination of two or more of NA-11, NA-21, NA-45 (produced by Asahi Denka, Japan), etc.

[0042] The role of the nucleating agent in the present invention is to regulate the crystal structure of the polypropylene composition so that the hindered amine stabilizer, antioxidant and acid scavenger in the composition can work synergistically under irradiation conditions, thereby improving the melt flow rate and melt strength while improving transparency.

[0043] The present invention also provides a high-flow transparent polypropylene material, which is prepared by irradiating the high-flow transparent polypropylene composition.

[0044] According to a specific embodiment of the present invention, preferably, the irradiation is performed on a melt-plasticized product of the high-flow transparent polypropylene composition.

[0045] According to a specific embodiment of the present invention, preferably, the irradiation dose R is equal to the melt flow rate MFR of the high flow transparent polypropylene material.材料 and the melt flow rate MFR of the polypropylene resin used PP The following relationship exists:

[0046] MFR 材料 =(MFR PP ×6.2×R) / 23.72;

[0047] The unit of the irradiation dose R is kGy.

[0048] According to a specific embodiment of the present invention, preferably, the irradiation dose is 15-60 kGy, more preferably 20-40 kGy.

[0049] According to a specific embodiment of the present invention, preferably, the high-flow transparent polypropylene material has a melt flow rate measured at 230° C. and 2.16 kG weight greater than 30 g / 10 min, more preferably 60-300 g / 10 min.

[0050] According to a specific embodiment of the present invention, preferably, the haze of the high flow transparent polypropylene material is 5%-20%.

[0051] According to a specific embodiment of the present invention, preferably, the melt strength of the high-flow transparent polypropylene material is 10-30 mN.

[0052] According to a specific embodiment of the present invention, preferably, the yellowness index of the high-flow transparent polypropylene material is from -2.0 to 1.5.

[0053] According to a specific embodiment of the present invention, preferably, the impact strength of the high flow transparent polypropylene material is 4-10 kJ / m 2 .

[0054] The present invention also provides a method for preparing a high-fluidity transparent polypropylene material, wherein the preparation method comprises:

[0055] S1, melt-plasticizing the high-flow transparent polypropylene composition;

[0056] S2, filtering the melted and plasticized composition, and then cooling and underwater pelletizing to form composition particles;

[0057] S3. The composite particles are irradiated to obtain a high-flow transparent polypropylene material.

[0058] According to a specific embodiment of the present invention, preferably, the method for preparing the above-mentioned high-flow transparent polypropylene material specifically comprises the following steps:

[0059] S1. Mix polypropylene resin, hindered amine stabilizer, antioxidant, acid scavenger and nucleating agent in proportion, or add them into an extruder in proportion to melt and plasticize;

[0060] S2, filtering the melted and plasticized composition through a filter screen, and then cooling and underwater pelletizing to form composition particles;

[0061] S3. The composite particles are irradiated with a high-energy electron beam or a cobalt source at a dose of 15-60 kGy to obtain a high-flow transparent polypropylene material.

[0062] In the prior art, when high-flow polypropylene is prepared by peroxide degradation, the residual peroxide will make the polypropylene have an unpleasant smell, affecting its application in fields with high requirements for hygiene and safety performance. High-flow polypropylene can be produced by polymerization method on large-scale production equipment through hydrogen adjustment method, but a large amount of hydrogen needs to be added to adjust the molecular weight of polypropylene, which has an adverse effect on the stability of the production equipment. In addition, it is generally believed that irradiation can cause polyethylene resin to cross-link and degrade polypropylene resin, and it is generally believed that adding hindered amine stabilizers can prevent the influence of irradiation on the resin, so that its performance remains stable, that is, the melt flow rate is not affected by irradiation, and has the characteristic of irradiation resistance. However, in the present invention, under specific formulas and irradiation doses, the melt flow rate of polypropylene added with hindered amine stabilizers after irradiation is significantly improved.

[0063] Therefore, compared with the prior art, the beneficial effects of the present invention are:

[0064] (1) High-flow transparent polypropylene material can be obtained without peroxide degradation, avoiding the adverse effects of peroxide addition on the odor, hygiene and safety performance of the product.

[0065] (2) There is no need to add a large amount of hydrogen to adjust the molecular weight of polypropylene, and stable production can be achieved on existing production equipment.

[0066] (3) The polypropylene material obtained by the method of the present invention has the characteristics of high fluidity, high transparency and high melt strength, and its melt flow rate can be regulated and designed, and has a wide range of applications. DETAILED DESCRIPTION

[0067] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0068] The sources of raw materials and testing methods used in the embodiments of the present invention are as follows:

[0069] Melt strength is usually expressed as melt tensile tension. The test conditions for melt tension are: using a Gottfert RT2000 advanced capillary rheometer equipped with a Rheotens module. During the test, the plunger moves downward to extrude the melt downward from the capillary die. The extruded melt thread passes through the force wheel and is pulled onto the take-up wheel. The vertical distance between the force wheel and the die is about 450mm. The force wheel is placed on a balance. The take-up wheel accelerates uniformly and tends to pull the force wheel away from the balance. Changes in the balance reading reflect the magnitude of the tension. The length of the test die is 20mm and the inner diameter is 2mm; the plunger movement speed is 0.2mm / s; the test temperature is 170℃; the melt thread is subjected to an initial velocity of 11.3mm / s and an acceleration of 6mm / s 2 The traction of the reel and the melt tension at break are characterized by the melt strength.

[0070] The content of ethylene and butene in random copolymer polypropylene was measured by infrared spectroscopy: the wave number was 758-679cm -1 Absorption area and wave number in the range 4482-3950cm -1 The ethylene content was calculated from the absorption area in the range of 779-750 cm -1 Absorption area and wave number in the range 4482-3950cm -1 The butene content was calculated from the absorption area within the range.

[0071] Melt flow rate MFR of high flow transparent polypropylene material 材料 and the melt flow rate MFR of the polypropylene resin used PP There is the following relationship between the radiation dose R (kGy):

[0072] MFR 材料 =(MFR PP ×6.2×R) / 23.72

[0073] Preparation Example 1

[0074] The preparation method of the polypropylene random copolymer in the present invention is as follows:

[0075] In a loop reactor, propylene and ethylene or propylene and butene are used as raw materials, a catalyst, an electron donor and an antistatic agent are added, and random copolymer polypropylene is obtained by controlling the reaction pressure, temperature, concentration of ethylene or butene in the loop reactor and the amount of hydrogen added. The catalyst is selected to have high polymerization activity, good hydrogen tunability and excellent copolymerization performance, and the external electron donor can be cyclohexyl-methyl-dimethoxysilane (DonorC).

[0076] In order to reduce the generation of a large amount of high-viscosity, low-molecular-weight ethylene-propylene or propylene-butylene random copolymers during the reaction, the concentration of ethylene or butylene and the concentration of hydrogen in the loop reactor need to be controlled to reduce the high-viscosity random substances as much as possible. At the same time, avoid large vibrations in the axial flow operation of the reactor to ensure stable operation of the device.

[0077] Preparation Example 2

[0078] The preparation method of hexadecyl poly-2,2,6,6-tetramethylpiperidinol-4-methylacrylate in the present invention is as follows:

[0079] 0.3 g of hexadecane bromide, 0.15 g of CuBr, 0.17 g of bpy (bipyridine) and 10 g of 2,2,6,6-tetramethylpiperidinol-4-methylacrylate were added to an ampoule in sequence, and deoxygenated by three freeze-pump-thaw cycles, followed by sealing and reacting in a 90°C oil bath. After 10 hours, the ampoule was taken out and plunged into liquid nitrogen to terminate the reaction. After the product was dissolved and diluted with tetrahydrofuran, the metal catalyst was removed by a neutral alumina column. The filtrate was concentrated and precipitated in methanol / water (v / v, 1 / 1), and the resulting product was vacuum dried at 50°C to obtain hexadecyl poly 2,2,6,6-tetramethylpiperidinol-4-methylacrylate H-(CH 2 CH 2 ) 8 -b-(TMPM) 20 -.

[0080] Preparation Example 3

[0081] The preparation method of poly 1,2,2,6,6-pentamethylpiperidinol-4-methylacrylate in the present invention is as follows:

[0082] Preparation of poly 1,2,2,6,6-pentamethylpiperidinol-4-methylacrylate: 0.1 g of azobisisobutyronitrile, 18 g of 1,2,2,6,6-pentamethylpiperidinol-4-methylacrylate, and 30 ml of acetone were added to a polymerization tube in sequence, mixed evenly, and then cooled with liquid nitrogen, vacuumed, nitrogen-purged, and thawed for 3 times, sealed under vacuum, and stirred at 75°C for 4 hours. The crude product was precipitated in n-hexane and dried to obtain poly 1,2,2,6,6-pentamethylpiperidinol-4-methylacrylate.

[0083] Example 1

[0084] This embodiment provides a high-flow transparent polypropylene material and a preparation method thereof, which comprises the following steps:

[0085] Polypropylene resin (ethylene-propylene random copolymer polypropylene, melt flow rate 10.0g / 10min, ethylene content 2.5%), 0.05% hexadecyl poly 2,2,6,6-tetramethylpiperidinol-4-methylacrylate based on the mass of polypropylene, 0.2% composite antioxidant (antioxidant 1010: antioxidant 168 = 1:2) based on the mass of polypropylene, 0.05% acid scavenger calcium stearate based on the mass of polypropylene, 0.2% nucleating agent NX8000 based on the mass of polypropylene, are melt-plasticized. The melt-plasticized composition is filtered through a filter screen and then cooled to form composition particles. The composition particles are irradiated with a cobalt source at a dose of 35kGy to obtain a high-flow transparent polypropylene material.

[0086] Example 2

[0087] This embodiment provides a high-flow transparent polypropylene material and a preparation method thereof, which comprises the following steps:

[0088] Polypropylene resin (ethylene-propylene random copolymer polypropylene, melt flow rate 20.0g / 10min, ethylene content 3.0%), 0.02% of poly 1,2,2,6,6-pentamethylpiperidinol-4-methylacrylate based on the mass of polypropylene, 0.11% of composite antioxidant (antioxidant 1076: antioxidant 626 = 1:1) based on the mass of polypropylene, 0.03% of acid scavenger hydrotalcite based on the mass of polypropylene, 0.06% of nucleating agent (NX8000 / 3988, 1:1) based on the mass of polypropylene, are melt-plasticized. The melt-plasticized composition is filtered through a filter and then cooled to form composition particles. The composition particles are irradiated with a high-energy electron beam at a dose of 26kGy to obtain a high-flow transparent polypropylene material.

[0089] Example 3

[0090] This embodiment provides a high-flow transparent polypropylene material and a preparation method thereof, which comprises the following steps:

[0091] Polypropylene resin (ethylene-propylene random copolymer polypropylene, melt flow rate 2.0g / 10min, ethylene content 1.5%), 0.06% GW-770 based on the mass of polypropylene, 0.23% composite antioxidant (antioxidant 330: antioxidant 626 = 1:3) based on the mass of polypropylene, 0.04% acid scavenger calcium stearate based on the mass of polypropylene, 0.15% nucleating agent NA-45 based on the mass of polypropylene, are melt-plasticized. The melt-plasticized composition is filtered through a filter screen and then cooled to form composition particles. The composition particles are irradiated with a high-energy electron beam at a dose of 60kGy to obtain a high-flow transparent polypropylene material.

[0092] Example 4

[0093] This embodiment provides a high-flow transparent polypropylene material and a preparation method thereof, which comprises the following steps:

[0094] Polypropylene resin (ethylene-propylene random copolymer polypropylene, melt flow rate 60.0g / 10min, ethylene content 3.5%), 0.10% GW-123 based on the mass of polypropylene, 0.43% composite antioxidant (antioxidant 300: antioxidant 168 = 1:2.5) based on the mass of polypropylene, 0.08% acid scavenger (hydrotalcite / calcium stearate, 1:1) based on the mass of polypropylene, 0.21% nucleating agent 3988 based on the mass of polypropylene, are melt-plasticized. The melt-plasticized composition is filtered through a filter screen and then cooled to form composition particles. The composition particles are irradiated with a cobalt source at a dose of 18kGy to obtain a high-flow transparent polypropylene material.

[0095] Example 5

[0096] This embodiment provides a high-flow transparent polypropylene material and a preparation method thereof, which comprises the following steps:

[0097] Polypropylene resin (ethylene-propylene random copolymer polypropylene, melt flow rate 4.0g / 10min, ethylene content 7.5%), 0.08% GW-3853 based on the mass of polypropylene, 0.5% composite antioxidant (antioxidant 1010: thiodipropionate = 1:1.5) based on the mass of polypropylene, 0.07% acid scavenger calcium stearate based on the mass of polypropylene, 0.25% nucleating agent (NX8000 / NA45, 1:2) based on the mass of polypropylene are melt-plasticized. The melt-plasticized composition is filtered through a filter screen and then cooled to form composition particles. The composition particles are irradiated with a cobalt source at a dose of 41kGy to obtain a high-flow transparent polypropylene material.

[0098] Example 6

[0099] This embodiment provides a high-flow transparent polypropylene material and a preparation method thereof, which comprises the following steps:

[0100] Polypropylene resin (propylene-butene random copolymer polypropylene, melt flow rate 3.0g / 10min, butene content 9.5%), 0.07% GW-944 based on the mass of polypropylene, 0.35% composite antioxidant (antioxidant 1076: thiodipropionate = 1:2) based on the mass of polypropylene, 0.09% acid scavenger (hydrotalcite / calcium stearate is 2:1) based on the mass of polypropylene, 0.30% nucleating agent (3988 / NA-45, 2:1) based on the mass of polypropylene are melt-plasticized. The melt-plasticized composition is filtered through a filter screen and then cooled to form composition particles. The composition particles are irradiated with a cobalt source at a dose of 56kGy to obtain a high-flow transparent polypropylene material.

[0101] Example 7

[0102] This embodiment provides a high-flow transparent polypropylene material and a preparation method thereof, which comprises the following steps:

[0103] Polypropylene resin (propylene-butene random copolymer polypropylene, melt flow rate 40.0g / 10min, butene content 1.5%), 0.04% GW-622 based on the mass of polypropylene, 0.15% composite antioxidant (antioxidant 300: antioxidant 626 = 1:1.2) based on the mass of polypropylene, 0.06% acid scavenger hydrotalcite based on the mass of polypropylene, 0.18% nucleating agent 3988 based on the mass of polypropylene, are melt-plasticized. The melt-plasticized composition is filtered through a filter screen and then cooled to form composition particles. The composition particles are irradiated with a cobalt source at a dose of 20kGy to obtain a high-flow transparent polypropylene material.

[0104] Example 8

[0105] This embodiment provides a high-flow transparent polypropylene material and a preparation method thereof, which comprises the following steps:

[0106] Polypropylene resin (propylene-butene random copolymer polypropylene, melt flow rate 15.0g / 10min, butene content 3.5%), 0.03% GW-119 based on the mass of polypropylene, 0.30% composite antioxidant (antioxidant 1076: antioxidant 168 = 1:2.3) based on the mass of polypropylene, 0.10% acid scavenger (hydrotalcite / calcium stearate, 1:2) based on the mass of polypropylene, 0.10% nucleating agent NA-45 based on the mass of polypropylene are melt-plasticized. The melt-plasticized composition is filtered through a filter screen and then cooled to form composition particles. The composition particles are irradiated with a high-energy electron beam at a dose of 30kGy to obtain a high-flow transparent polypropylene material.

[0107] Comparative Example 1

[0108] This comparative example provides a high-flow transparent polypropylene material and a preparation method thereof, which comprises the following steps:

[0109] Polypropylene resin (homopolymer polypropylene, melt flow rate 10.0g / 10min), 0.05% hexadecyl poly 2,2,6,6-tetramethylpiperidinol-4-methylacrylate based on the mass of polypropylene, 0.2% composite antioxidant (antioxidant 1010: antioxidant 168 = 1:2) based on the mass of polypropylene, 0.05% acid scavenger calcium stearate based on the mass of polypropylene, 0.2% nucleating agent NX8000 based on the mass of polypropylene, are melt-plasticized. The melt-plasticized composition is filtered through a filter screen and then cooled to form composition particles. The composition particles are irradiated with a cobalt source at a dose of 35kGy to obtain a polypropylene material.

[0110] Comparative Example 2

[0111] This comparative example provides a high-flow transparent polypropylene material and a preparation method thereof, which comprises the following steps:

[0112] Polypropylene resin (ethylene-propylene random copolymer polypropylene, melt flow rate 20.0g / 10min, ethylene content 3.0%), 0.11% of composite antioxidant (antioxidant 1076: antioxidant 626 = 1:1) based on the mass of polypropylene, 0.03% of acid scavenger hydrotalcite based on the mass of polypropylene, and 0.06% of nucleating agent (NX8000 / 3988, 1:1) based on the mass of polypropylene are melt-plasticized. The melt-plasticized composition is filtered through a filter and then cooled to form composition particles. The composition particles are irradiated with a high-energy electron beam at a dose of 26kGy to obtain a polypropylene material.

[0113] Comparative Example 3

[0114] This comparative example provides a high-flow transparent polypropylene material and a preparation method thereof, which comprises the following steps:

[0115] Polypropylene resin (ethylene-propylene random copolymer polypropylene, melt flow rate 2.0g / 10min, ethylene content 1.5%), 0.06% GW-770 based on the mass of polypropylene, 0.23% composite antioxidant (antioxidant 330: antioxidant 626 = 1:3) based on the mass of polypropylene, 0.04% acid scavenger calcium stearate based on the mass of polypropylene, are melt-plasticized. The melt-plasticized composition is filtered through a filter screen and then cooled to form composition particles. The composition particles are irradiated with a high-energy electron beam at a dose of 60kGy to obtain a polypropylene material.

[0116] Comparative Example 4

[0117] This comparative example provides a high-flow transparent polypropylene material and a preparation method thereof, which comprises the following steps:

[0118] Polypropylene resin (ethylene-propylene random copolymer polypropylene, melt flow rate 60.0g / 10min, ethylene content 3.5%), 0.10% GW-123 based on the mass of polypropylene, 0.08% acid scavenger (hydrotalcite / calcium stearate, 1:1) based on the mass of polypropylene, and 0.21% nucleating agent 3988 based on the mass of polypropylene are melt-plasticized. The melt-plasticized composition is filtered through a filter screen and then cooled to form composition particles. The composition particles are irradiated with a cobalt source at a dose of 18kGy to obtain a polypropylene material.

[0119] Comparative Example 5

[0120] This comparative example provides a high-flow transparent polypropylene material and a preparation method thereof, which comprises the following steps:

[0121] Polypropylene resin (ethylene-propylene random copolymer polypropylene, melt flow rate 4.0g / 10min, ethylene content 7.5%), 0.08% GW-3853 based on the mass of polypropylene, 0.5% composite antioxidant (antioxidant 1010: thiodipropionate = 1:1.5) based on the mass of polypropylene, 0.07% acid scavenger calcium stearate based on the mass of polypropylene, 0.25% nucleating agent (NX8000 / NA45, 1:2) based on the mass of polypropylene are melt-plasticized. The melt-plasticized composition is filtered through a filter screen and then cooled to form composition particles. The composition particles are irradiated with a cobalt source at a dose of 100kGy to obtain a polypropylene material.

[0122] The following will analyze and compare the specific experimental data for the performance of polypropylene materials. The experimental results are shown in Table 1:

[0123] Table 1. Performance comparison of examples and comparative examples

[0124]

[0125] From the comparison between the examples and the comparative examples in Table 1, it can be seen that the polypropylene material obtained by adopting the technical solution of the present invention has the advantages of high fluidity (MFR greater than 30g / 10min), good transparency (haze less than 20%), high melt strength (greater than or equal to 10mN), low yellow index (less than 1.5), and the toughness of the product does not decrease significantly compared with that before irradiation (high impact strength, greater than 4kJ / m 2 ). In contrast, the polypropylene materials obtained by using homopolymerized polypropylene (Comparative Example 1), or lacking hindered amine stabilizer (Comparative Example 2), or lacking nucleating agent (Comparative Example 3), or lacking antioxidant (Comparative Example 4) in the preparation process cannot exert the synergistic interaction between polypropylene resin and each component, and the yellow index after irradiation is high (greater than 3.0), the melt strength is low (less than or equal to 5mN), and the melt flow rate changes higher or lower than the expected range, and the purpose of the present invention cannot be achieved. If the irradiation dose in the preparation process does not meet the technical solution of the present invention (Comparative Example 5), the yellow index of the polypropylene material obtained after irradiation is high, the melt flow rate changes less than the expected range, and the toughness of the product decreases significantly, and the purpose of the present invention cannot be achieved.

[0126] The inventors of the present invention have found that by selecting appropriate polypropylene resin and nucleating agent, the condensed structure of polypropylene can be regulated, so that the polypropylene resin, antioxidant, and hindered amine stabilizer can produce unexpected changes together under appropriate irradiation doses: the molecular weight of the polypropylene resin is reduced (MFR is increased compared to before irradiation), and a branched structure that can improve the melt strength is formed. This structural change can produce good effects, so that the obtained polypropylene composition has the characteristics of high flow, high transparency, and high melt strength, and can be used to prepare household items, milk tea cups, storage boxes, medical syringes, etc.

Claims

1. A high-flow transparent polypropylene composition, in, The raw material composition of the high-flow transparent polypropylene composition comprises: (A) polypropylene resin; (B) 0.005% to 0.2% of a hindered amine stabilizer based on the mass of the polypropylene resin; (C) 0.05% to 0.6% of an antioxidant based on the mass of the polypropylene resin; (D) 0.01% to 0.2% of an acid scavenger based on the mass of the polypropylene resin; and (E) 0.03% to 0.4% of a nucleating agent based on the mass of the polypropylene resin; Wherein, the polypropylene resin is a random copolymer polypropylene with a melt flow rate less than or equal to 60g / 10min.

2. The high-flow transparent polypropylene composition according to claim 1, in, The amount of the hindered amine stabilizer is 0.02%-0.1%; Preferably, the amount of the antioxidant is 0.1%-0.5%; Preferably, the amount of the acid scavenger is 0.03-0.1%; Preferably, the amount of the nucleating agent is 0.05-0.3%.

3. The high-flow transparent polypropylene composition according to claim 1, in, The random copolymer polypropylene is ethylene-propylene random copolymer polypropylene and / or propylene-butene random copolymer polypropylene; Preferably, the ethylene content in the ethylene-propylene random copolymer polypropylene is 1-8wt%, and the melt flow rate is 5-40g / 10min; Preferably, the propylene-butene random copolymer polypropylene has a butene content of 1-10 wt % and a melt flow rate of 8-50 g / 10 min.

4. The high-flow transparent polypropylene composition according to claim 3, in, The random copolymer polypropylene is ethylene-propylene random copolymer polypropylene, the ethylene content of the ethylene-propylene random copolymer polypropylene is 2-5wt%, and the melt flow rate is 8-20g / 10min.

5. The high-flow transparent polypropylene composition according to claim 1 or 2, in, The hindered amine stabilizer includes bis(2,2,6,6,-tetramethyl-4-piperidinyl) sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 2,2,6,6-tetramethyl-4-piperidinyl stearate, poly{(6-morpholinyl-5-triazine-2,4-diyl)(2,2,6,6-tetramethylpiperidinyl)iminohexamethylene[(2,2,6,6-tetramethylpiperidinyl)-imino]}, poly{[6-[(1,1,3,3-tetramethylbutyl)amino]]-1,3,5-triazine-2,4-[(2,2, 6,6,-tetramethyl-piperidinyl)imino]-1,6-hexanediol[(2,2,6,6-tetramethyl-4-piperidinyl)imino]}, poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinethanol) succinate, high molecular weight triazine-piperidinyl condensate, polymers of the reaction products of N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine with 2,4,6-trichloro-1,3,5-triazine and N-butyl-1-butylamine and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine, structural units containing -(TMPM) m1 -polymeric hindered amine stabilizer, structural unit comprising -(PMPM) m2 -One or a combination of two or more of the polymeric hindered amine stabilizers; Wherein, TMPM is a structural unit obtained by polymerization of 2,2,6,6-tetramethylpiperidinol-4-methylacrylate, and PMPM is a structural unit obtained by polymerization of 1,2,2,6,6-pentamethylpiperidinol-4-methylacrylate; m1 and m2 represent the degree of polymerization, and m1 and m2 are 4-100; Preferably, the structural unit comprises -(TMPM) m1 -The polymeric hindered amine stabilizer is hexadecyl poly 2,2,6,6-tetramethylpiperidinol-4-methylacrylate; the structural unit comprises -(PMPM) m2 -The polymeric hindered amine stabilizer is poly 1,2,2,6,6-pentamethylpiperidinol-4-methacrylate.

6. The high-flow transparent polypropylene composition according to claim 1 or 2, in, The antioxidant is a phenolic antioxidant, or a composite antioxidant of a phenolic antioxidant and other antioxidants; Preferably, the other antioxidants include phosphite antioxidants and / or thioester antioxidants.

7. The high-flow transparent polypropylene composition according to claim 6, in, In the composite antioxidant, the phenolic antioxidant is the main antioxidant, and the other antioxidants are auxiliary antioxidants; Preferably, the mass ratio of the primary antioxidant to the secondary antioxidant is 1:1-1:

3.

8. The high-flow transparent polypropylene composition according to claim 6 or 7, in, The phenolic antioxidant includes one or a combination of two or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol, 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 4,4'-thiobis(6-tert-butyl-3-methylphenol).

9. The high-flow transparent polypropylene composition according to any one of claims 6 to 8, in, The other antioxidants include one or a combination of two or more of tris(2,4-di-tert-butylphenyl)phosphite, bis(2,4-di-tert-butylphenol)pentaerythritol diphosphite, and thiodipropionate; Preferably, the composite antioxidant comprises one or a combination of two or more of a mixture of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol and tris(2,4-di-tert-butylphenyl)phosphite, a mixture of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and bis(2,4-di-tert-butylphenol)pentaerythritol diphosphite, and a mixture of 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and thiodipropionate.

10. The high-flow transparent polypropylene composition according to claim 1 or 2, in, The acid scavenger is calcium stearate and / or hydrotalcite.

11. The high-flow transparent polypropylene composition according to claim 1 or 2, in, The nucleating agent includes one or a combination of two or more of sorbitol and phosphate; Preferably, the sorbitol nucleating agent is millad 3988 and / or NX8000; Preferably, the phosphate nucleating agent is one of NA-11, NA-21, NA-45, or a combination of two or more thereof.

12. A high-flow transparent polypropylene material, which is prepared by irradiating the high-flow transparent polypropylene composition according to any one of claims 1 to 11; Preferably, the radiation dose R is about the same as the melt flow rate MFR of the high flow transparent polypropylene material. 材料 and the melt flow rate MFR of the polypropylene resin used PP The following relationship exists: MFR 材料 =(MFR PP ×6.2×R) / 23.72; The unit of the irradiation dose R is kGy.

13. The high flow transparent polypropylene material according to claim 12, in, The irradiation dose is 15-60 kGy, preferably 20-40 kGy.

14. The high flow transparent polypropylene material according to claim 12, in, The melt flow rate of the high-flow transparent polypropylene material is greater than 30 g / 10 min, preferably 60-300 g / 10 min; Preferably, the haze of the high flow transparent polypropylene material is 5%-20%; Preferably, the melt strength of the high flow transparent polypropylene material is 10-30 mN; Preferably, the yellowness index of the high-flow transparent polypropylene material is -2.0 to 1.5; Preferably, the impact strength of the high flow transparent polypropylene material is 4-10 kJ / m 2 .

15. A method for preparing the high-flow transparent polypropylene material according to any one of claims 12 to 14, in, The preparation method comprises: S1, melt-plasticizing the high-flow transparent polypropylene composition; S2, filtering the melted and plasticized composition, and then cooling and underwater pelletizing to form composition particles; S3. The composite particles are irradiated by a high-energy electron beam or a cobalt source to obtain a high-flow transparent polypropylene material.

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