阅读说明：本技术 一种超高熔融指数的熔喷聚丙烯复合材料的制备方法 (Preparation method of melt-blown polypropylene composite material with ultrahigh melt index ) 是由 蔡雄雄 于 2020-12-22 设计创作，主要内容包括：本发明属于高分子材料技术领域,具体涉及一种超高熔融指数的熔喷聚丙烯复合材料及其制备方法。包括如下步骤：(1),将聚丙烯树脂、山梨醇类成核剂、润滑剂和抗氧剂通过高速搅拌混合机混合均匀成混合料,将混合料投入双螺杆挤出机；(2),将液态有机过氧化物类引发剂通过精密计量泵从挤出机筒体特定位置注入双螺杆挤出机,进行高温熔融和螺杆剪切、真空干燥、过滤、挤出、冷却切粒、筛选以及收料得到超高熔融指数的熔喷聚丙烯复合材料。该制备方法通过严格控制各步骤的温度参数及原料重量,使制得的复合材料具有超高的流动性、窄的分子量分布、低气味及耐热氧老化性能,利用其制得的熔喷布具有优异的过滤性能,并且不易氧化发脆。(The invention belongs to the technical field of high polymer materials, and particularly relates to a melt-blown polypropylene composite material with an ultrahigh melt index and a preparation method thereof. The method comprises the following steps: (1) uniformly mixing polypropylene resin, a sorbitol nucleating agent, a lubricant and an antioxidant by a high-speed stirring mixer to obtain a mixture, and putting the mixture into a double-screw extruder; (2) injecting a liquid organic peroxide initiator into a double-screw extruder from a specific position of an extruder barrel through a precision metering pump, and carrying out high-temperature melting, screw shearing, vacuum drying, filtering, extruding, cooling, granulating, screening and receiving to obtain the melt-blown polypropylene composite material with the ultrahigh melt index. The preparation method ensures that the prepared composite material has ultrahigh fluidity, narrow molecular weight distribution, low odor and thermal-oxidative aging resistance by strictly controlling the temperature parameters and the weight of the raw materials in each step, and the melt-blown fabric prepared by the preparation method has excellent filtering performance and is not easy to oxidize and embrittle.)

1. A preparation method of a melt-blown polypropylene composite material with an ultrahigh melt index is characterized by comprising the following steps: (1) uniformly mixing polypropylene resin, a sorbitol nucleating agent, a lubricant and an antioxidant by a high-speed stirring mixer to obtain a mixture, and putting the mixture into a double-screw extruder; (2) injecting a liquid organic peroxide initiator into a double-screw extruder from a specific position of an extruder barrel through a precision metering pump, and carrying out high-temperature melting, screw shearing, vacuum drying, filtering, extruding, cooling, granulating, screening and receiving to obtain the melt-blown polypropylene composite material with the ultrahigh melt index;

the double-screw extruder comprises a double-screw extruder body, a double-screw extruder body and a double-screw extruder, wherein the length-diameter ratio of the double-screw extruder body is 44-60, the temperature of the extruder body is 145-260 ℃, the rotating speed of a screw is 200-600 revolutions per minute, the specific position of the extruder body is 2-6 sections counted from a feed end, polypropylene resin is at least one of homo-polypropylene or co-polypropylene, the melt index of the polypropylene resin is 25-100 g/10min, and the weight parts of the polypropylene resin, sorbitol nucleating agent, lubricant, antioxidant and peroxide initiator are 100 parts of polypropylene resin, 0.2-0.5 part of sorbitol nucleating agent, 0.1-0.3 part of lubricant, 0.2-0.4 part of antioxidant and 0.3-1 part of peroxide initiator.

2. The method of claim 1, wherein the sorbitol based nucleating agent is at least one of dibenzylidene sorbitol, bis (p-methyldibenzylidene) sorbitol, bis (3, 4-dimethyldibenzylidene) sorbitol, bis (4-methyldibenzylidene) sorbitol, bis (p-ethylbenzylidene) sorbitol, bis (p-methylbenzylidene) sorbic acid, bis- (p-ethyldiylideneisopropyl) sorbitol, bis (p-chloro-substituted benzylidene) sorbitol, bis (p-chloromethyldibenzylidene) sorbitol, 4' - (dimethylthiodibenzylidene) sorbitol, and 1-propyl-1, 3,2,4, -bis (p-n-propyldibenzylidene) sorbitol.

3. The method of claim 2, wherein the sorbitol nucleating agent is bis (p-methyldibenzylidene) sorbitol 4,4' - (dimethylthiodibenzylidene) sorbitol and 1-propyl-1, 3,2,4, -bis (p-n-propyldibenzylidene) sorbitol in a weight ratio of 1: (1-3) in the presence of a catalyst.

4. The method of claim 3, wherein the peroxide initiator is at least one of 2, 5-dimethyl-2, 5-di-tert-butylperoxy hexane, 1, 4-di-tert-butylperoxy isopropyl benzene, dicumyl peroxide, and di-tert-butyl peroxide.

5. The method of claim 4, wherein the peroxide initiator is a mixture of 2, 5-dimethyl-2, 5-di-tert-butylperoxy hexane and 1, 4-di-tert-butylperoxy isopropyl benzene at a weight ratio of 1: 1.

6. The method of claim 5, wherein the antioxidant is at least one of pentaerythritol tetrakis [ β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], N-octadecyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, N' -bis- (3- (35-di-tert-butyl-4-hydroxyphenyl) propionyl) hexanediamine, and tris [2, 4-di-tert-butylphenyl ] phosphite.

7. The method of claim 6, wherein the antioxidant is pentaerythritol tetrakis [ β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], N-octadecyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, and N, N' -bis- (3- (35-di-tert-butyl-4-hydroxyphenyl) propionyl) hexanediamine in a weight ratio of 1: (1-2): (1-2) in the presence of a catalyst.

8. The method of claim 7, wherein the lubricant is at least one of pentaerythritol stearate, oleamide, and erucamide.

9. The method of claim 8, wherein the lubricant is pentaerythritol stearate, and the weight ratio of oleamide to erucamide is 1: (1-3): 1, in a mixture of the components.

10. The preparation method of the melt-blown polypropylene composite material with the ultrahigh melt index as claimed in any one of claims 1 to 9, wherein a feeding hopper is arranged on the upper side of a feeding port of the twin-screw extruder, a weight loss scale for accurately weighing raw materials is arranged above the feeding hopper, a high-speed mixer for placing a mixture is arranged above the weight loss scale, a filling port is arranged on 2-6 sections of the twin-screw extruder, a precise metering pump and an initiator storage tank for precisely adding a peroxide initiator are sequentially connected above the filling port, an automatic screen changer, a cooling device, a blower, a granulator, a vibrating screen and a receiving hopper are sequentially arranged at an outlet of a die head of the twin-screw extruder, the temperature of the cooling device is controlled to be 5-40 ℃, and the temperature control precision is +/-2 ℃.

Technical Field

The invention belongs to the technical field of high polymer materials, and particularly relates to a preparation method of a melt-blown polypropylene composite material with an ultrahigh melt index.

Background

Polypropylene is a polymer obtained by addition polymerization of propylene. Is white wax-like material, and has transparent and light appearance. The density is 0.89-0.91 g/cm3, the flame retardant is flammable, the melting point is 165 ℃, the softening temperature is about 155 ℃, and the use temperature range is-30-140 ℃. Can resist corrosion of acid, alkali, salt solution and various organic solvents at the temperature of below 80 ℃, and can be decomposed at high temperature and under the action of oxidation. The polypropylene is widely applied to the production of fiber products such as clothes, blankets and the like, medical instruments, automobiles, bicycles, parts, conveying pipelines, chemical containers and the like, and is also used for packaging foods and medicines. With the development of economic society, people put forward higher and higher requirements on environmental quality and pay higher and higher attention to self health. However, the extreme bad weather such as haze and sand storm, and the frequent occurrence of infectious diseases such as SARS and avian influenza lead people to gradually recognize the importance of the respiratory protection articles. PM2.5 (inhalable particles with the diameter W2.5wn) is an important index for measuring the air quality, and the core material applied to respiratory protection products such as masks, dust masks and the like is a melt-blown non-woven fabric material, namely, a non-woven fabric produced by a non-woven fabric melt-blown process which is produced by adopting raw materials such as polypropylene granules and the like through a continuous one-step method of high-temperature melting, spinning, lapping and hot pressing coiling. As an important raw material of non-woven fabric products, ultrahigh-fluidity polypropylene also puts higher and higher requirements on the non-woven fabric products. As a respiratory protection product closely related to human health, the product is closely related to the health and comfort of people due to the fact that the product is non-toxic, odorless and nonirritating. Ultra-high flow polypropylene generally refers to polypropylene materials with very high melt index (MI ^1500g/10 min), which are commonly used as the primary material for meltblown process nonwovens. The method is characterized in that a peroxide free radical initiator is added into the polypropylene, and the ultrahigh-fluidity polypropylene is obtained by initiating a degradation reaction of controllable free radical molecular chain breakage (namely an oxygen regulation method), so that the production cost is low, the melt index is accurately adjustable, the product is suitable for the melt-blown non-woven fabric production process, and the method is more adopted in the production of the existing ultrahigh-fluidity polypropylene.

However, in the prior art, the ultra-high melt index polypropylene product produced by polypropylene degradation initiated by a peroxide free radical initiator contains a lot of initiator residues and small molecular byproducts formed by free radical degradation reaction, so that the volatile organic matter (V0C) content of the product is high, the odor level generally exceeds the industrial hygiene requirement, and the respiratory protection product carrying a large amount of organic small molecules and aromatic substances is bound to be absorbed into the body in the using process of a consumer, which can affect the health of the user in the past. And the polypropylene melt-blown material used in the fields of polypropylene melt-blown fabric, protective clothing and the like at present is still not ideal in the aspect of ultrahigh fluidity, and under the condition of continuous melt-blown fabric spinning, the fluidity is insufficient and the melt index is unstable, so that the melt-blown fabric spinning is not uniform, and the filtration grade is influenced. And because the thermal oxidation resistance of the melt-blown polypropylene material is poor, the melt-blown cloth is easy to oxidize and become brittle.

Disclosure of Invention

In order to overcome the defects and shortcomings in the prior art, the invention aims to provide the preparation method of the melt-blown polypropylene composite material with the ultrahigh melt index, the preparation method is convenient to operate and control, stable in quality, high in production efficiency, low in production cost and suitable for large-scale industrial production, the temperature parameters and the raw material weight of each step are strictly controlled, so that the prepared melt-blown polypropylene composite material with the ultrahigh melt index has ultrahigh fluidity, narrow molecular weight distribution, low odor and thermal-oxidative aging resistance, and the melt-blown cloth prepared by using the preparation method has excellent filtering performance and is not easy to oxidize and become brittle.

The purpose of the invention is realized by the following technical scheme: a preparation method of a melt-blown polypropylene composite material with an ultrahigh melt index comprises the following steps: (1) uniformly mixing polypropylene resin, a sorbitol nucleating agent, a lubricant and an antioxidant by a high-speed stirring mixer to obtain a mixture, and putting the mixture into a double-screw extruder; (2) injecting a liquid organic peroxide initiator into a double-screw extruder from a specific position of an extruder barrel through a precision metering pump, and carrying out high-temperature melting, screw shearing, vacuum drying, filtering, extruding, cooling, granulating, screening and receiving to obtain the melt-blown polypropylene composite material with the ultrahigh melt index;

the double-screw extruder comprises a double-screw extruder body, a double-screw extruder body and a double-screw extruder, wherein the length-diameter ratio of the double-screw extruder body is 44-60, the temperature of the extruder body is 145-260 ℃, the rotating speed of a screw is 200-600 revolutions per minute, the specific position of the extruder body is 2-6 sections counted from a feed end, polypropylene resin is at least one of homo-polypropylene or co-polypropylene, the melt index of the polypropylene resin is 25-100 g/10min, and the weight parts of the polypropylene resin, sorbitol nucleating agent, lubricant, antioxidant and peroxide initiator are 100 parts of polypropylene resin, 0.2-0.5 part of sorbitol nucleating agent, 0.1-0.3 part of lubricant, 0.2-0.4 part of antioxidant and 0.3-1 part of peroxide initiator.

The preparation method disclosed by the invention is convenient to operate and control, stable in quality, high in production efficiency, low in production cost and suitable for large-scale industrial production, the temperature parameters and the raw material weight of each step are strictly controlled, so that the prepared melt-blown polypropylene composite material with the ultrahigh melt index has ultrahigh fluidity, narrow molecular weight distribution, low odor and thermal-oxidative aging resistance, and the melt-blown fabric prepared by using the preparation method has excellent filtering performance and is not easy to oxidize and embrittle.

Preferably, the weight ratio of the liquid organic peroxide initiator fed in the sections 2-6 counted from the feeding end is 1 (1-3): 1: 1.

The initiator is added in the invention in a distributed manner, so that the initiator and the polypropylene resin are fully and uniformly mixed, peroxide can be more uniformly dispersed in polypropylene during degradation, the obtained product has narrower molecular weight distribution, more stable fluidity and more stable later-stage melt-blown fabric process.

Preferably, the liquid organic peroxide initiator is fed in a weight ratio of 1:1:1:1:1:1 in stages 2 to 6 from the feed end.

Preferably, the sorbitol-based nucleating agent is at least one of dibenzylidene sorbitol, bis (p-methyldibenzylidene) sorbitol, bis (3, 4-dimethyldibenzylidene) sorbitol, bis (4-methyldibenzylidene) sorbitol, bis (p-ethylbenzylidene) sorbitol, bis (p-methylbenzylidene) sorbic acid, bis- (p-ethyldiylideneisopropyl) sorbitol, bis (p-chloro-substituted benzylidene) sorbitol, bis (p-chloromethyldibenzylidene) sorbitol, 4' - (dimethylthiodibenzylidene) sorbitol, and 1-propyl-1, 3,2,4, -bis (p-n-propyldibenzylidene) sorbitol.

The similarity of the sorbitol nucleating agent and the polypropylene molecular structure is beneficial to the crystallization nucleation effect, the polypropylene crystallization effect can be promoted, the nucleating agent serves as a heterogeneous crystal nucleus in the crystallization process of polypropylene, and the nonpolar part of the nucleating agent forms dents on the surface of the polypropylene, accommodates and aligns the molecular chains of the polypropylene, and promotes the nucleation.

Preferably, the sorbitol nucleating agent is bis (p-methyldibenzylidene) sorbitol 4,4' - (dimethylthiodibenzylidene) sorbitol and 1-propyl-1, 3,2,4, -bis (p-n-propyldibenzylidene) sorbitol in a weight ratio of 1: (1-3): (1-3) in the presence of a catalyst.

Preferably, the peroxide initiator is at least one of 2, 5-dimethyl-2, 5-di-tert-butyl hexane peroxide, 1, 4-di-tert-butylperoxyisopropyl benzene, dicumyl peroxide and di-tert-butyl peroxide.

Preferably, the peroxide initiator is a mixture of 2, 5-dimethyl-2, 5-di-tert-butylperoxy hexane and 1, 4-di-tert-butylperoxy isopropyl benzene in a weight ratio of 1: 1.

Preferably, the antioxidant is at least one of pentaerythritol tetrakis [ β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], N-octadecyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, N' -bis- (3- (35-di-tert-butyl-4-hydroxyphenyl) propionyl) hexanediamine, and tris [2, 4-di-tert-butylphenyl ] phosphite.

Preferably, the antioxidant is pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] and tris [2, 4-di-tert-butylphenyl ] phosphite in a weight ratio of 1: (1-2) in the presence of a catalyst.

Tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester is one of multiple hindered phenol antioxidants, and has the advantages of no toxicity, no pollution and no discoloration. The phenol structure of the compound is easy to capture free radicals in a high molecular material system, and meanwhile, tert-butyl on the ortho position of the phenol position of the tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester belongs to an electron donating group, can activate the hydroxyl of phenol, improve the free radical capture capability, provide larger steric hindrance of the hydroxyl on the tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester phenol while activating the phenol by tert-butyl, only small free radical molecules can participate in the reaction, and the other additives have large molecular volume and are difficult to approach without reaction, so that the tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester does not damage the other additives, and the original functions of the two additives are invalid. The tris [2, 4-di-tert-butylphenyl ] phosphite belongs to phosphite secondary antibiotics, achieves the purpose of antioxidation by decomposing the peroxide generated by further degrading plastics, mainly provides thermal processing stability, and generates synergistic effect when used together with a tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester antioxidant.

Preferably, the lubricant is at least one of pentaerythritol stearate, oleamide and erucamide.

By adopting the lubricant, the internal lubricity and the external lubricity of the PP composite material can be improved, so that the PP composite material is easy to extrude and form and has good processability. The erucamide has good internal and external lubricity, so that the material is easy to extrude and form, sticky feeling is not generated, the prepared product is easy to process, the product is easy to demould after extrusion and the thermal stability and weather resistance of the product can be improved.

Preferably, the lubricant is pentaerythritol stearate, oleamide and erucamide in a weight ratio of 1: (1-3): 1, in a mixture of the components.

Preferably, the upper side of the feed inlet of the double-screw extruder is provided with a feeding hopper, a weightlessness scale for accurately weighing the raw materials is arranged above the feeding hopper, a high-speed mixer for placing a mixture is arranged above the weightlessness scale, 2-6 sections of the double-screw extruder are provided with filling ports, a precision metering pump and an initiator storage tank for accurately adding a peroxide initiator are sequentially connected and arranged above the filling ports, an automatic screen changer, a cooling device, a blower, a granulator, a vibrating screen and a receiving hopper are sequentially arranged at the die head outlet of the double-screw extruder, the temperature of the cooling device is controlled to be 5-40 ℃, and the temperature control precision is +/-2 ℃.

Compared with the prior art, the invention has the advantages that: the preparation method disclosed by the invention is convenient to operate and control, stable in quality, high in production efficiency, low in production cost and suitable for large-scale industrial production, the temperature parameters and the raw material weight of each step are strictly controlled, so that the prepared melt-blown polypropylene composite material with the ultrahigh melt index has ultrahigh fluidity, narrow molecular weight distribution, low odor and thermal-oxidative aging resistance, and the melt-blown fabric prepared by using the preparation method has excellent filtering performance and is not easy to oxidize and embrittle.

Detailed Description

The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1

A preparation method of a melt-blown polypropylene composite material with an ultrahigh melt index comprises the following steps: (1) uniformly mixing polypropylene resin, a sorbitol nucleating agent, a lubricant and an antioxidant by a high-speed stirring mixer to obtain a mixture, and putting the mixture into a double-screw extruder; (2) injecting a liquid organic peroxide initiator into a double-screw extruder from a specific position of an extruder barrel through a precision metering pump, and carrying out high-temperature melting, screw shearing, vacuum drying, filtering, extruding, cooling, granulating, screening and receiving to obtain the melt-blown polypropylene composite material with the ultrahigh melt index;

the length-diameter ratio of the double-screw extruder is 48, the temperature of a barrel of the extruder is 190 ℃ in a first zone, 250 ℃ in a second zone, 250 ℃ in a third zone, 240 ℃ in a fourth zone, 240 ℃ in a fifth zone, 190 ℃ in a sixth zone, 170 ℃ in a seventh zone, 170 ℃ in an eighth zone, 150 ℃ in a ninth zone, 140 ℃ in a tenth zone, 170 ℃ in a die head, 145-260 ℃ in the barrel of the extruder, the rotating speed of a screw is 600 revolutions per minute, the barrel of the extruder is specially positioned from a feed end to a 2-6 section, the polypropylene resin is at least one of homo-polypropylene or co-polypropylene, the melt index of the polypropylene resin is 100g/10min, and the parts by weight of the polypropylene resin, the sorbitol nucleating agent, the lubricant, the antioxidant and the peroxide initiator are 100 parts by weight and 100 parts by weight of the polypropylene resin, 0.5 part of sorbitol nucleating agent, 0.3 part of lubricant, 0.4 part of antioxidant and 1 part of peroxide initiator.

Preferably, the sorbitol nucleating agent is bis (p-methyldibenzylidene) sorbitol 4,4' - (dimethylthiodibenzylidene) sorbitol and 1-propyl-1, 3,2,4, -bis (p-n-propyldibenzylidene) sorbitol in a weight ratio of 1:1, in a mixture of the components.

Preferably, the peroxide initiator is a mixture of 2, 5-dimethyl-2, 5-di-tert-butylperoxy hexane and 1, 4-di-tert-butylperoxy isopropyl benzene in a weight ratio of 1: 1.

Preferably, the antioxidant is pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] and tris [2, 4-di-tert-butylphenyl ] phosphite in a weight ratio of 1:1, in a mixture of the components.

Preferably, the lubricant is pentaerythritol stearate, oleamide and erucamide in a weight ratio of 1: 3: 1, in a mixture of the components.

Preferably, the upper side of the feed inlet of the double-screw extruder is provided with a feeding hopper, a weightlessness scale for accurately weighing the raw materials is arranged above the feeding hopper, a high-speed mixer for placing a mixture is arranged above the weightlessness scale, 2-6 sections of the double-screw extruder are provided with filling ports, a precision metering pump and an initiator storage tank for accurately adding a peroxide initiator are sequentially connected and arranged above the filling ports, an automatic screen changer, a cooling device, a blower, a granulator, a vibrating screen and a receiving hopper are sequentially arranged at the die head outlet of the double-screw extruder, the temperature of the cooling device is controlled to be 40 ℃, and the temperature control precision is +/-2 ℃.

Example 2

A preparation method of a melt-blown polypropylene composite material with an ultrahigh melt index comprises the following steps: (1) uniformly mixing polypropylene resin, a sorbitol nucleating agent, a lubricant and an antioxidant by a high-speed stirring mixer to obtain a mixture, and putting the mixture into a double-screw extruder; (2) injecting a liquid organic peroxide initiator into a double-screw extruder from a specific position of an extruder barrel through a precision metering pump, and carrying out high-temperature melting, screw shearing, vacuum drying, filtering, extruding, cooling, granulating, screening and receiving to obtain the melt-blown polypropylene composite material with the ultrahigh melt index;

the length-diameter ratio of the double-screw extruder is 48, the temperature of a barrel of the extruder is 190 ℃ in a first zone, 250 ℃ in a second zone, 250 ℃ in a third zone, 240 ℃ in a fourth zone, 240 ℃ in a fifth zone, 190 ℃ in a sixth zone, 170 ℃ in a seventh zone, 170 ℃ in an eighth zone, 150 ℃ in a ninth zone, 140 ℃ in a tenth zone, 170 ℃ in a die head, and 200 revolutions per minute, the barrel of the extruder is specially positioned at 2-6 sections from the feed end, the polypropylene resin is at least one of homo-polypropylene or co-polypropylene, the melt index of the polypropylene resin is 25-100 g/10min, and the weight parts of the polypropylene resin, the sorbitol nucleating agent, the lubricant, the antioxidant and the peroxide initiator are 100 parts of the polypropylene resin, 0.3 part of the sorbitol nucleating agent, 0.2 part of lubricant, 0.3 part of antioxidant and 0.5 part of peroxide initiator.

Preferably, the sorbitol nucleating agent is bis (p-methyldibenzylidene) sorbitol 4,4' - (dimethylthiodibenzylidene) sorbitol and 1-propyl-1, 3,2,4, -bis (p-n-propyldibenzylidene) sorbitol in a weight ratio of 1:1:1, in a mixture of the components.

Preferably, the peroxide initiator is a mixture of 2, 5-dimethyl-2, 5-di-tert-butylperoxy hexane and 1, 4-di-tert-butylperoxy isopropyl benzene in a weight ratio of 1: 1.

Preferably, the antioxidant is pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] and tris [2, 4-di-tert-butylphenyl ] phosphite in a weight ratio of 1:1, in a mixture of the components.

Preferably, the lubricant is pentaerythritol stearate, oleamide and erucamide in a weight ratio of 1:1:1, in a mixture of the components.

Preferably, the upper side of the feed inlet of the double-screw extruder is provided with a feeding hopper, a weightlessness scale for accurately weighing the raw materials is arranged above the feeding hopper, a high-speed mixer for placing a mixture is arranged above the weightlessness scale, 2-6 sections of the double-screw extruder are provided with filling ports, a precision metering pump and an initiator storage tank for accurately adding a peroxide initiator are sequentially connected and arranged above the filling ports, an automatic screen changer, a cooling device, a blower, a granulator, a vibrating screen and a receiving hopper are sequentially arranged at the die head outlet of the double-screw extruder, the temperature of the cooling device is controlled to be 5-40 ℃, and the temperature control precision is +/-2 ℃.

Example 3

A preparation method of a melt-blown polypropylene composite material with an ultrahigh melt index comprises the following steps: (1) uniformly mixing polypropylene resin, a sorbitol nucleating agent, a lubricant and an antioxidant by a high-speed stirring mixer to obtain a mixture, and putting the mixture into a double-screw extruder; (2) injecting a liquid organic peroxide initiator into a double-screw extruder from a specific position of an extruder barrel through a precision metering pump, and carrying out high-temperature melting, screw shearing, vacuum drying, filtering, extruding, cooling, granulating, screening and receiving to obtain the melt-blown polypropylene composite material with the ultrahigh melt index;

the length-diameter ratio of the double-screw extruder is 44, the temperature of a barrel of the extruder is 190 ℃ in a first zone, 250 ℃ in a second zone, 250 ℃ in a third zone, 240 ℃ in a fourth zone, 240 ℃ in a fifth zone, 190 ℃ in a sixth zone, 170 ℃ in a seventh zone, 170 ℃ in an eighth zone, 150 ℃ in a ninth zone, 140 ℃ in a tenth zone, 170 ℃ in a die head, and 200 revolutions per minute, the barrel of the extruder is specially positioned at 2-6 sections from the feed end, the polypropylene resin is at least one of homo-polypropylene or co-polypropylene, the melt index of the polypropylene resin is 25-100 g/10min, and the weight parts of the polypropylene resin, the sorbitol nucleating agent, the lubricant, the antioxidant and the peroxide initiator are 100 parts of the polypropylene resin, 0.2 part of the sorbitol nucleating agent, 0.1 part of lubricant, 0.2 part of antioxidant and 0.3 part of peroxide initiator.

Preferably, the sorbitol nucleating agent is bis (p-methyldibenzylidene) sorbitol 4,4' - (dimethylthiodibenzylidene) sorbitol and 1-propyl-1, 3,2,4, -bis (p-n-propyldibenzylidene) sorbitol in a weight ratio of 1:1:1, in a mixture of the components.

Preferably, the antioxidant is pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] and tris [2, 4-di-tert-butylphenyl ] phosphite in a weight ratio of 1:1, in a mixture of the components.

Preferably, the antioxidant is pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] and tris [2, 4-di-tert-butylphenyl ] phosphite in a weight ratio of 1:1 of the mixture of composition.

Preferably, the lubricant is pentaerythritol stearate, oleamide and erucamide in a weight ratio of 1:1:1, in a mixture of the components.

Preferably, double screw extruder feed inlet upside is equipped with the loading hopper, the loading hopper top is equipped with the weightless balance that is used for accurately weighing the raw materials, the top of weightless balance is equipped with the high-speed blendor that is used for placing the mixture, be provided with the filler on the double screw extruder 2-6 section, filler top connects gradually and is equipped with precision metering pump and the initiator storage jar that is used for the accurate peroxide initiator that adds, double screw extruder die head exit is equipped with automatic screen changer, cooling device, hair-dryer, pelleter, shale shaker and connects the hopper in proper order, cooling device's temperature control is 25 ℃, and the temperature control precision is 2 ℃.

Example 4

A preparation method of a melt-blown polypropylene composite material with an ultrahigh melt index comprises the following steps: (1) uniformly mixing polypropylene resin, a sorbitol nucleating agent, a lubricant and an antioxidant by a high-speed stirring mixer to obtain a mixture, and putting the mixture into a double-screw extruder; (2) injecting a liquid organic peroxide initiator into a double-screw extruder from a specific position of an extruder barrel through a precision metering pump, and carrying out high-temperature melting, screw shearing, vacuum drying, filtering, extruding, cooling, granulating, screening and receiving to obtain the melt-blown polypropylene composite material with the ultrahigh melt index;

the length-diameter ratio of the double-screw extruder is 60, the temperature of the barrel of the extruder is 190 ℃ in the first zone, 250 ℃ in the second zone, 250 ℃ in the third zone, 240 ℃ in the fourth zone, 240 ℃ in the fifth zone, 190 ℃ in the sixth zone, 170 ℃ in the seventh zone, 170 ℃ in the eighth zone, 150 ℃ in the ninth zone, 140 ℃ in the tenth zone, 170 ℃ in the die head, and the rotation speed of the screw is 200-600 revolutions per minute, the specific position of the barrel of the extruder is 2-6 sections from the feed end, the polypropylene resin is at least one of homo-polypropylene or co-polypropylene, the melt index of the polypropylene resin is 25g/10min, and the weight parts of the polypropylene resin, the sorbitol nucleating agent, the lubricant, the antioxidant and the peroxide initiator are 100 parts of the polypropylene resin, 0.5 part of sorbitol nucleating agent, 0.3 part of lubricant, 0.4 part of antioxidant and 1 part of peroxide initiator.

Preferably, the sorbitol nucleating agent is dibenzylidene sorbitol.

Preferably, the peroxide initiator is a mixture of 2, 5-dimethyl-2, 5-di-tert-butylperoxy hexane and 1, 4-di-tert-butylperoxy isopropyl benzene in a weight ratio of 1: 1.

Preferably, the antioxidant is pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] and tris [2, 4-di-tert-butylphenyl ] phosphite in a weight ratio of 1: 2, and (b) a mixture of the components.

Preferably, the lubricant is pentaerythritol stearate, oleamide and erucamide in a weight ratio of 1:1:1, in a mixture of the components.

Preferably, double screw extruder feed inlet upside is equipped with the loading hopper, the loading hopper top is equipped with the weightless balance that is used for accurately weighing the raw materials, the top of weightless balance is equipped with the high-speed blendor that is used for placing the mixture, be provided with the filler on the double screw extruder 2-6 section, filler top connects gradually and is equipped with precision metering pump and the initiator storage jar that is used for the accurate peroxide initiator that adds, double screw extruder die head exit is equipped with automatic screen changer, cooling device, hair-dryer, pelleter, shale shaker and connects the hopper in proper order, cooling device's temperature control is 25 ℃, and the temperature control precision is 2 ℃.

Example 5

A preparation method of a melt-blown polypropylene composite material with an ultrahigh melt index comprises the following steps: (1) uniformly mixing polypropylene resin, a sorbitol nucleating agent, a lubricant and an antioxidant by a high-speed stirring mixer to obtain a mixture, and putting the mixture into a double-screw extruder; (2) injecting a liquid organic peroxide initiator into a double-screw extruder from a specific position of an extruder barrel through a precision metering pump, and carrying out high-temperature melting, screw shearing, vacuum drying, filtering, extruding, cooling, granulating, screening and receiving to obtain the melt-blown polypropylene composite material with the ultrahigh melt index;

the length-diameter ratio of the double-screw extruder is 60, the temperature of the barrel of the extruder is 190 ℃ in the first zone, 250 ℃ in the second zone, 250 ℃ in the third zone, 240 ℃ in the fourth zone, 240 ℃ in the fifth zone, 190 ℃ in the sixth zone, 170 ℃ in the seventh zone, 170 ℃ in the eighth zone, 150 ℃ in the ninth zone, 140 ℃ in the tenth zone, 170 ℃ in the die head, and 200-600 revolutions per minute of a screw, the specific position of the barrel of the extruder is 2-6 sections from the feed end, the polypropylene resin is at least one of homo-polypropylene or co-polypropylene, the melt index of the polypropylene resin is 100g/10min, and the weight parts of the polypropylene resin, the sorbitol nucleating agent, the lubricant, the antioxidant and the peroxide initiator are 100 parts of the polypropylene resin, 0.5 part of sorbitol nucleating agent, 0.3 part of lubricant, 0.4 part of antioxidant and 1 part of peroxide initiator.

Preferably, the sorbitol nucleating agent is bis (p-methyldibenzylidene) sorbitol 4,4' - (dimethylthiodibenzylidene) sorbitol and 1-propyl-1, 3,2,4, -bis (p-n-propyldibenzylidene) sorbitol in a weight ratio of 1: 2: 3, and (b) a mixture of the components.

Preferably, the peroxide initiator is a mixture of 2, 5-dimethyl-2, 5-di-tert-butylperoxy hexane and 1, 4-di-tert-butylperoxy isopropyl benzene in a weight ratio of 1: 1.

Preferably, the weight ratio of the peroxide initiator to the peroxide initiator fed in the 2 nd to 6 th sections from the feed end is 1:1:1:1:1: 1.

Preferably, the antioxidant is pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] and tris [2, 4-di-tert-butylphenyl ] phosphite in a weight ratio of 1: 2, and (b) a mixture of the components.

Preferably, the lubricant is pentaerythritol stearate, oleamide and erucamide in a weight ratio of 1:1:1, in a mixture of the components.

Preferably, double screw extruder feed inlet upside is equipped with the loading hopper, the loading hopper top is equipped with the weightless balance that is used for accurately weighing the raw materials, the top of weightless balance is equipped with the high-speed blendor that is used for placing the mixture, be provided with the filler on the double screw extruder 2-6 section, filler top connects gradually and is equipped with precision metering pump and the initiator storage jar that is used for the accurate peroxide initiator that adds, double screw extruder die head exit is equipped with automatic screen changer, cooling device, hair-dryer, pelleter, shale shaker and connects the hopper in proper order, cooling device's temperature control is 30 ℃, and the temperature control precision is 2 ℃.

The ultra-high melt index melt blown polypropylene composites prepared in examples 1-5 were tested for performance and the results are shown in table 1.

TABLE 1

The test data show that the melt-blown polypropylene composite material with the ultrahigh melt index, prepared by the invention, has the characteristics of ultrahigh melt index, high rigidity, high light transmittance, yellowing resistance and the like.

While particular embodiments of the present invention have been described, it is to be understood that the invention is not limited to the precise embodiments described above, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.