An environmentally friendly processing aid for polyolefins and its preparation method

Abstract

This invention relates to the field of polymer materials technology, specifically disclosing an environmentally friendly processing aid for polyolefins and its preparation method. The environmentally friendly processing aid for polyolefins includes a first component and a second component. The first component includes an antioxidant-modified oligomer A, and the second component is obtained by extrusion granulation of oligomer B, an organosilicon polymer, and a catalyst. By weight, the amounts of each component are: oligomer A 1-10 parts, antioxidant 0.1-2 parts, oligomer B 5-40 parts, organosilicon polymer 5-80 parts, and catalyst 0.1-5 parts. The processing aid of this invention does not contain perfluorinated or polyfluoroalkyl compounds. When used in the processing of polyolefins, it has advantages such as low addition amount, short onset time, good viscosity reduction effect, and effective improvement of product gloss. Furthermore, it can effectively form a dynamic lubricating layer on the surface of metal walls.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to an environmentally friendly processing aid for polyolefins and its preparation method. Background Technology

[0002] In recent decades, the polymer processing industry has developed rapidly, with production equipment and laboratories established worldwide. A major challenge in this field is processing large volumes of polymer materials with low energy consumption while maintaining high product quality. However, the productivity of many industrialized polymer processing operations is severely limited by polymer processing instabilities exceeding critical productivity levels. This leads to surface irregularities / defects in the processed polymers, thus reducing product quality. Recently, with the commercialization of metallocene polyolefins, processing polymers with superior physical properties has become crucial, but their processing performance is significantly reduced due to their narrow molecular weight distribution. Typical processing instabilities include the sharkskin phenomenon, also known as surface melt fracture (SMF) and total melt fracture (GMF). When extrusion productivity exceeds a critical value, stress on the free surface at the die exit causes periodic cracks, resulting in small-amplitude periodic deformations on the extrudate surface. At higher throughput rates, this leads to more severe surface melt fracture with irregularities (GMF).

[0003] Polymer processing aids (PPAs) have long been used to effectively eliminate the instability of sharkskin or slow it down to relatively high shear rates, thereby significantly improving production rates. Fluoroelastics, copolymers of vinylidene fluoride and hexafluoropropylene, are the most extensively studied and used PPAs in polyolefin processing. When added at low concentrations, they effectively form a dynamic lubricating layer on mold surfaces, promoting the processing of molten polymers. Stearates and other inorganic modifiers (such as boron nitride and montmorillonite nanoclay) have also been found as effective PPAs for processing various polymers. Furthermore, fluoropolymers combined with polyethylene glycol (PEG) or aliphatic polyesters as co-additives, and PEG combined with nanoclay, have been found to exhibit enhanced properties compared to single-component PPAs due to the synergistic effect of the co-additives.

[0004] Recently, the European Chemicals Agency (ECHA) published a proposed regulation restricting per- and polyfluoroalkyl substances (PFAS) on its official website. Once implemented, this regulation will have a significant impact on the fluorochemical industry. Besides the EU, many countries and regions worldwide are developing regulations to control PFAS. PFAS are known as persistent organic compounds (POPS) or permanent chemicals due to their long degradation time in soil and water. PFAS also readily migrate in the environment. When ingested by humans and animals, PFAS accumulate in the body, producing toxicity, affecting the immune and reproductive systems, disrupting the endocrine system, and possessing potential carcinogenicity. Therefore, the demand for PFAS-free and fluorine-free polymer processing aids has attracted widespread attention in the industry. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an environmentally friendly processing aid for polyolefins and its preparation method, which is free of perfluorinated and polyfluoroalkyl compounds. When used in the polyolefin processing, it has the advantages of small addition amount, short onset time, good viscosity reduction effect, and effective improvement of product gloss. Furthermore, due to the use of modified and catalytically reacted oligomers, the heat resistance and film-forming properties of the oligomers are improved, so that there is no decomposition problem under normal processing temperature and continuous production conditions, and it will not cause discoloration of the final product. It can also effectively form a dynamic lubrication layer on the metal wall surface.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0007] An environmentally friendly processing aid for polyolefins includes a first component and a second component. The first component includes an antioxidant-modified oligomer A, and the second component is obtained by extrusion granulation of oligomer B, an organosilicon polymer, and a catalyst. By weight, the amounts of each component are: 1-10 parts of oligomer A, 0.1-2 parts of antioxidant, 5-40 parts of oligomer B, 5-80 parts of organosilicon polymer, and 0.1-5 parts of catalyst.

[0008] Preferably, the chemical formula of oligomer A is as follows:

[0009]

[0010] Where n is a natural number between 20 and 60.

[0011] Preferably, the antioxidant includes at least one of aromatic amine antioxidants, hindered phenolic antioxidants, thiodipropionates, phosphites, polyphosphates, thioether antioxidants, and thiophenol antioxidants.

[0012] Preferably, the oligomer B includes at least one of polyethylene, polypropylene, hyperbranched polyethylene, and hyperbranched polypropylene.

[0013] Preferably, the organosilicon polymer includes at least one of organosilicon raw rubber and hyperbranched organosilicon resin. Further, the organosilicon raw rubber includes at least one of methyl vinyl polysiloxane, methyl polysiloxane, vinyl polysiloxane, hydroxy vinyl polysiloxane, hydroxy polysiloxane, phenyl vinyl polysiloxane, phenyl polysiloxane, and amino polysiloxane.

[0014] Preferably, the catalyst comprises at least one of dibutyltin dilaurate, an organic peroxide crosslinking agent, and a maleic anhydride grafting agent.

[0015] To better address the aforementioned technical problems, the present invention also discloses the following technical solutions:

[0016] A method for preparing an environmentally friendly processing aid for polyolefins includes the following steps:

[0017] (1) Heat oligomer A to a molten state;

[0018] (2) Slowly add antioxidant to the above system, stir the reaction to obtain melt;

[0019] (3) The above melt is spray-granulated to obtain the first component;

[0020] (4) Oligomer B, a portion of the organosilicon polymer, and the catalyst are added to a granulator for primary granulation, followed by the addition of the remaining organosilicon polymer for secondary granulation to obtain the second component.

[0021] (5) Mix the first component and the second component to obtain an environmentally friendly processing aid for polyolefins.

[0022] Preferably, in step (1), the temperature at which the material is heated to the molten state is 80-100°C.

[0023] Preferably, in step (2), the temperature of the stirring reaction is 80-100℃ and the time is 5-30min.

[0024] Preferably, in step (4), the mass ratio of a portion of the organosilicon polymer to the remaining organosilicon polymer is 1:1.

[0025] Preferably, in step (4), the temperature of primary granulation and secondary granulation is 130℃-200℃.

[0026] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0027] 1. The processing aid provided by this invention is immiscible with the bulk polymer and exists in the bulk polymer matrix as phase-separated droplets, exhibiting good dispersibility. During processing, the dispersed processing aid droplets migrate to the mold surface under shearing action, forming a dynamic lubrication layer. This significantly reduces the surface adsorption of incompatible bulk polymers, thereby promoting their sliding in the mold and effectively improving the quality and yield of processed products.

[0028] 2. When the processing aid of the present invention is used in the polyolefin processing, it has the advantages of small addition amount, short onset time, good viscosity reduction effect, and effective improvement of product gloss. In addition, it uses modified and catalytically reacted oligomers, which improves the heat resistance and film-forming properties of the oligomers, so that there is no decomposition problem under normal processing temperature and continuous production conditions, and it will not cause discoloration of the final product.

[0029] 3. In preparing the processing aid, the present invention first mixes an antioxidant with molten oligomer A and reacts them under certain conditions to obtain a first component. Then, the other components are granulated to obtain a second component. Finally, the first and second components are mixed. Through the above operations, the oligomer A is first grafted and modified with an antioxidant, which greatly improves the heat resistance of the oligomer A. Moreover, the surface of the modified oligomer A has certain polar functional groups, which can effectively improve the lubricity of the product.

[0030] 4. In preparing the second component, the present invention adds the organosilicon polymer in batches and performs multiple granulations. By repeatedly branching polar functional groups at the ends or sides of the oligomer B main chain, the resulting polymer processing aid has a strong affinity with the metal surface of the die head, effectively forming a stable dynamic lubrication layer. Therefore, it can improve the pressure drop and output of the product during processing, as well as the quality of the product. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 This shows the melting and pressing conditions of the sample in the application examples. Detailed Implementation

[0033] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0034] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0035] Unless otherwise specified, the raw materials used in the following embodiments are all commercially available products, and the conditions described are all conventional conditions in the art.

[0036] Example 1

[0037] A method for preparing an environmentally friendly processing aid for polyolefins includes the following steps:

[0038] S1. Add 10g of polyethylene glycol (molecular weight 5000) to a three-necked flask and heat it to molten state at 80°C. Slowly add 0.5g of trinonylphenyl phosphite and continue heating and stirring for 20min to obtain a melt. Powder the melt in a spray tower at 80°C to obtain the first component.

[0039] S2. 100g LLDPE (MI: 10), 100g methyl vinyl polysiloxane (molecular weight of 500,000), and 1g maleic anhydride grafting catalyst are melt-reacted and granulated at 180°C to obtain granulated product. Then, the above granulated product is melt-reacted and granulated again with 100g methyl vinyl polysiloxane (molecular weight of 500,000) at 180°C.

[0040] S3. Mix the first and second components to obtain an environmentally friendly processing aid for polyolefins.

[0041] Example 2

[0042] A method for preparing an environmentally friendly processing aid for polyolefins includes the following steps:

[0043] S1. Add 10g of polyethylene glycol (molecular weight 5000) to a three-necked flask and heat it to molten state at 100℃. Slowly add 0.5g of trinonylphenyl phosphite and continue heating and stirring for 20min to obtain a melt. Powder it in a spray tower at 90℃ to obtain the first particulate component.

[0044] S2. 100g LLDPE (MI: 10), 100g methyl vinyl polysiloxane (molecular weight of 600,000), and 1g maleic anhydride grafting catalyst are melt-reacted and granulated at 190°C to obtain granular product. The above granular product is then melt-reacted and granulated again with 100g methyl vinyl polysiloxane (molecular weight of 600,000) at 190°C to obtain the second component.

[0045] S3. Mix the first component and the second component to obtain an environmentally friendly processing aid for polyolefins.

[0046] Example 3

[0047] A method for preparing an environmentally friendly processing aid for polyolefins includes the following steps:

[0048] S1. Add 10g of polyethylene glycol (molecular weight 5000) to a three-necked flask and heat it to molten state at 100℃. Slowly add 0.5g of tris(2,4-di-tert-butylphenyl) phosphite and continue heating and stirring for 20min to obtain a melt. Powder it in a powder spraying tower at 90℃ to obtain the first particulate component.

[0049] S2. 100g of copolymer polypropylene (MI: 15), 100g of methyl vinyl polysiloxane (molecular weight 1 million), and 1g of maleic anhydride grafting catalyst are melt-reacted and granulated at 190°C to obtain granular product. The above granular product is then melt-reacted and granulated again with 200g of methyl vinyl polysiloxane (molecular weight 900,000) at 190°C to obtain the second component.

[0050] S3. Mix the first component and the second component to obtain an environmentally friendly processing aid for polyolefins.

[0051] Example 4

[0052] A method for preparing an environmentally friendly processing aid for polyolefins includes the following steps:

[0053] S1. Add 10g of polyethylene glycol (molecular weight 5000) to a three-necked flask and heat it to molten state at 100℃. Slowly add 0.5g of tris(2,4-di-tert-butylphenyl) phosphite and continue heating and stirring for 20min to obtain a melt. Then, pulverize the melt in a powder spraying tower at 90℃ to obtain the first particulate component.

[0054] S2. 100g of copolymer polypropylene (MI: 15), 100g of hydroxyl polysiloxane (molecular weight 1 million), and 1g of catalyst organic peroxide crosslinking agent are melt-reacted and granulated at 190°C to obtain granular product. The above granular product is then melt-reacted and granulated with 100g of methyl vinyl polysiloxane (molecular weight 900,000) at 190°C to obtain the second component.

[0055] S3. Mix the first component and the second component to obtain an environmentally friendly processing aid for polyolefins.

[0056] Example 5

[0057] A method for preparing an environmentally friendly processing aid for polyolefins includes the following steps:

[0058] S1. Add 10g of polyethylene glycol (molecular weight 5000) to a three-necked flask and heat it to molten state at 100℃. Slowly add 0.5g of pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenol)propionate and continue heating and stirring for 20min to obtain a melt. Then, pulverize the melt in a powder spraying tower at 90℃ to obtain the first component in particulate form.

[0059] S2. 100g of copolymer polypropylene (MI: 15), 100g of methyl vinyl polysiloxane (molecular weight 900,000), and 0.5g of catalyst organic peroxide crosslinking agent are melt-reacted and granulated at 190°C to obtain granular product. The above granular product is then melt-reacted and granulated with 100g of vinyl polysiloxane (molecular weight 900,000) at 190°C to obtain the second component.

[0060] S3. Mix the first component and the second component to obtain an environmentally friendly processing aid for polyolefins.

[0061] Example 6

[0062] A method for preparing an environmentally friendly processing aid for polyolefins includes the following steps:

[0063] S1. Add 10g of polyethylene glycol (molecular weight 5000) to a three-necked flask and heat it to molten state at 100℃. Slowly add 0.5g of antioxidant pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenol)propionate) and continue heating and stirring for 20min to obtain a melt. Then, pulverize the melt in a powder spraying tower at 90℃ to obtain the first particulate component.

[0064] S2. 100g of copolymer polypropylene (MI: 15), 100g of methyl vinyl polysiloxane (molecular weight 900,000), and 0.5g of catalyst organic peroxide crosslinking agent are melt-reacted and granulated at 190°C to obtain granular product. The above granular product is then melt-reacted and granulated with 200g of hydroxyl polysiloxane (molecular weight 1,000,000) at 190°C to obtain the second component.

[0065] S3. Mix the first component and the second component to obtain an environmentally friendly processing aid for polyolefins.

[0066] The effects of the present invention will be further explained below with reference to Example 1 and in conjunction with the following comparative examples.

[0067] Comparative Example 1

[0068] Commercially available perfluorinated PPA.

[0069] Comparative Example 2

[0070] Commercially available 30wt% fluorinated PPA.

[0071] Comparative Example 3

[0072] Commercially available fluorine-free PPA.

[0073] Comparative Example 4

[0074] A method for preparing an environmentally friendly processing aid for polyolefins includes the following steps:

[0075] S1. Add 10g of polyethylene glycol (molecular weight 5000) to a three-necked flask and heat it to molten state at 80°C. Slowly add 0.5g of trinonylphenyl phosphite and continue heating and stirring for 20min to obtain a melt. Then, pulverize the melt in a powder spraying tower at 80°C to obtain the first particulate component.

[0076] S2. 100g LLDPE (MI: 10), 200g methyl vinyl polysiloxane (molecular weight 500,000) (molecular weight 1,000,000), 1g catalyst maleic anhydride grafting agent are melt-reacted and granulated at 180℃ to obtain the second component.

[0077] S3. Mix the first component and the second component to obtain the processing aid.

[0078] Comparative Example 5

[0079] A method for preparing an environmentally friendly processing aid for polyolefins includes the following steps:

[0080] S1. Add 10g of polyethylene glycol (molecular weight 5000) to a three-necked flask and heat it to molten state at 80°C. Slowly add 0.5g of trinonylphenyl phosphite and continue heating and stirring for 20min to obtain a melt. Powder the melt in a spray tower at 80°C to obtain the first component.

[0081] S2. The first component prepared above, 100g LLDPE (MI: 10), 100g methyl vinyl polysiloxane (molecular weight of 500,000), and 1g maleic anhydride grafting catalyst are melt-reacted and granulated at 180°C to obtain granulated product. Then, the granulated product is melt-reacted and granulated again with 100g methyl vinyl polysiloxane (molecular weight of 500,000) at 180°C to obtain processing aid.

[0082] Application Example 1

[0083] The processing aids from Examples 1-6 and Comparative Examples 1-5 were mixed with mLLDPE with an MI of 1 using a twin-screw extruder (L / D ratio of 44:1) at a temperature of 190°C to prepare masterbatches, each containing 5 wt% of the processing aids. The masterbatches were then mixed with mLLDPE with an MI of 1 at a mass ratio of 0.01:1. Samples were prepared in a capillary rheometer at 190°C and labeled as Sample 1, Sample 2, Sample 3, Sample 4, Sample 5, and Comparative Samples 1, 2, 3, 4, 5, 5, and 6, respectively. Sample 0 was pure mLLDPE with an MI of 1.

[0084] The above samples were subjected to performance tests. The test methods and results are as follows:

[0085] 1. The gradual disappearance of melt fracture in the above samples under a constant shear rate (20 r / min) was tested using a capillary rheometer. Specifically, in this experiment, extruded strips were produced using a capillary rheometer (length-to-diameter ratio 25:1, die 1 mm, temperature 180℃), and the surface melt fracture and melt pressure were observed using an optical microscope. Before each sample change, the samples were cleaned with a cleaning agent, and then the same results as for sample 0 were repeated with pure mLLDPE material before proceeding to the next sample. The test results are shown in Table 1 and... Figure 1 As shown.

[0086] Table 1

[0087]

[0088]

[0089] As can be seen from the results in Table 1, in terms of the elimination of melt fracture time and appearance, the surface morphology of samples 1-6 and control sample 1 gradually improved and stabilized at 1000s, and melt fracture was completely eliminated. Therefore, the semi-film formation at the die head is good, and a better dynamic lubrication layer can be formed, which can effectively improve the processing quality of the product.

[0090] from Figure 1 It can be seen that the melting pressure of the sample decreases with time and reaches equilibrium after 40 minutes, which can effectively improve the processing output.

[0091] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. An environmentally friendly processing aid for polyolefins, characterized in that: It includes a first component and a second component. The first component includes antioxidant-modified oligomer A, and the second component is obtained by extrusion granulation of oligomer B, organosilicon polymer, and catalyst. The amounts of each component by weight are as follows: oligomer A 1-10 parts, antioxidant 0.1-2 parts, oligomer B 5-40 parts, organosilicon polymer 5-80 parts, catalyst 0.1-5 parts; Its preparation method includes the following steps: (1) Heat oligomer A to a molten state at 80-100℃; (2) Add antioxidant slowly to the above system and stir at 80-100℃ for 5-30 minutes to obtain melt; (3) The above melt is spray-granulated to obtain the first component; (4) Oligomer B, part of the organosilicon polymer and catalyst are added to the granulator and granulated once at 130-200℃. Then the remaining organosilicon polymer is added and granulated twice at 130-200℃ to obtain the second component. The mass ratio of part of the organosilicon polymer to the remaining organosilicon polymer is 1:

1. (5) Mix the first component and the second component to obtain an environmentally friendly processing aid for polyolefins; The chemical formula of oligomer A is as follows: ， Where n is a natural number between 20 and 60; The antioxidants include at least one of aromatic amine antioxidants, hindered phenolic antioxidants, and phosphites; The oligomer B includes at least one of polyethylene, polypropylene, hyperbranched polyethylene, and hyperbranched polypropylene. The organosilicon polymer includes raw organosilicon rubber; the raw organosilicon rubber includes at least one of methyl vinyl polysiloxane, hydroxy vinyl polysiloxane, and phenyl vinyl polysiloxane. The catalyst includes at least one of an organic peroxide crosslinking agent and a maleic anhydride grafting agent.

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