Environment-friendly processing aid for polyolefin and preparation method of environment-friendly processing aid

Abstract

The invention relates to the technical field of high polymer materials, and particularly discloses an environment-friendly processing aid for polyolefin and a preparation method thereof.The environment-friendly processing aid for polyolefin comprises a first component and a second component, the first component comprises an antioxidant modified oligomer A, and the second component is prepared by extruding and granulating an oligomer B, an organosilicon polymer and a catalyst; the invention discloses a high-temperature-resistant low-smoke halogen-free flame retardant, which is prepared from the following components in parts by weight: 1 to 10 parts of oligomer A, 0.1 to 2 parts of antioxidant, 5 to 40 parts of oligomer B, 5 to 80 parts of organic silicon polymer and 0.1 to 5 parts of catalyst. The processing aid provided by the invention does not contain perfluorinated and polyfluoroalkyl compounds, has the advantages of small addition amount, short onset time, good viscosity reduction effect, effective improvement of product glossiness and the like when being used in a polyolefin processing process, and can effectively form a dynamic lubricating layer on the surface of a metal wall.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to an environmentally friendly processing aid for polyolefins and a preparation method thereof. Background Art

[0002] In recent decades, the polymer processing industry has developed rapidly, and the development of production equipment and laboratories has spread all over the world. The main challenge in this field is to process large amounts of polymer materials with lower energy consumption while maintaining high product quality. However, the productivity of many industrialized polymer processing operations is greatly limited by the instability of polymer processing beyond the critical productivity, which leads to surface irregularities / defects of the processed polymer, thereby reducing product quality. Recently, with the commercial use of metallocene polyolefins in the market, polymer processing with some superior physical properties is crucial, but its processing performance is greatly reduced due to its relatively narrow molecular weight distribution. Typical processing instabilities include shark skin phenomenon, also known as surface melt fracture (SMF) and total melt fracture (GMF). When the extrusion productivity exceeds the critical value, the stress on the free surface at the die outlet causes periodic cracks, which leads to small periodic deformations on the surface of the extrudate. At higher throughput rates, more severe irregular (GMF) appearance melt fracture occurs.

[0003] Polymer processing aids (PPAs) have long been used to effectively eliminate sharkskin instabilities or slow them down to fairly high shear rates, thereby significantly increasing production rates. Fluoroelastomers, copolymers of vinylidene fluoride and hexafluoropropylene, are the most intensively studied and used PPAs in polyolefin processing. When added in low concentrations, they effectively form a dynamic lubrication layer on the mold surface, facilitating the processing of molten polymers. Stearates and other inorganic modifiers such as boron nitride and montmorillonite nanoclays have also been found to be effective PPAs for processing various polymers. In addition, fluoropolymers have been combined with polyethylene glycol (PEG) or aliphatic polyesters as co-additives, and PEG has been combined with nanoclays and found to exhibit enhanced performance compared to single-component PPAs due to the synergistic effects exerted by the co-additives.

[0004] Recently, the European Chemicals Agency (ECHA) published a proposal for the restriction of per- and polyfluoroalkyl substances (PFAS) on its official website. Once implemented, this regulation will have a huge impact on the fluorine chemical industry. In addition to the EU, many countries and regions around the world are formulating control regulations for PFAS. PFAS is called "persistent organic compounds (POPS)" because of its long degradation time in soil and water, and is also called permanent chemicals. PFAS is also easy to migrate in the environment. When humans and animals ingest PFAS, PFAS will accumulate in the body and become toxic, affecting the immune system and reproductive system, interfering with the endocrine system, and is potentially carcinogenic. Therefore, the demand for PFAS-free and non-fluorinated 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: in view of the shortcomings of the prior art, an environmentally friendly processing aid for polyolefins and a preparation method thereof are provided. The processing aid does not contain perfluoro and polyfluoroalkyl compounds. When used in the processing of polyolefins, it has the advantages of small addition amount, short onset time, good viscosity reduction effect, and effective improvement of product gloss. In addition, 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 the final product will not be discolored, and a dynamic lubrication layer can be effectively formed on the metal wall surface.

[0006] In order to solve the above technical problems, the technical solution of the present invention is:

[0007] An environmentally friendly processing aid for polyolefins comprises a first component and a second component, wherein the first component comprises an antioxidant-modified oligomer A, and the second component is prepared by extrusion granulation of an oligomer B, an organic silicon polymer and a catalyst; in parts by weight, the dosage of each component is: 1-10 parts of oligomer A, 0.1-2 parts of antioxidant, 5-40 parts of oligomer B, 5-80 parts of organic silicon polymer, and 0.1-5 parts of catalyst.

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

[0009]

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

[0011] Preferably, the antioxidant includes at least one of aromatic amine antioxidants, hindered phenol antioxidants, thiodipropionate, phosphite, polyphosphate, 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 an organosilicon raw rubber and a hyperbranched organosilicon resin. Further, the organosilicon raw rubber includes at least one of methylvinylpolysiloxane, methylpolysiloxane, vinylpolysiloxane, hydroxyvinylpolysiloxane, hydroxypolysiloxane, phenylvinylpolysiloxane, phenylpolysiloxane and aminopolysiloxane.

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

[0015] In order to better solve the above technical problems, the present invention also discloses the following technical solutions:

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

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

[0018] (2) slowly adding an antioxidant to the above system, stirring and reacting to obtain a melt;

[0019] (3) spray granulating the melt to obtain a first component;

[0020] (4) Adding oligomer B, part of the organosilicon polymer, and the catalyst into a granulator for primary granulation, and then adding the remaining organosilicon polymer for secondary granulation to obtain the second component.

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

[0022] Preferably, in step (1), the temperature of heating to the molten state is 80-100°C.

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

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

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

[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 the present invention is immiscible with the bulk polymer and exists in the bulk polymer matrix in the form of phase-separated droplets, and has good dispersibility. During the processing, the dispersed processing aid droplets migrate to the mold surface under shearing action to form a dynamic lubrication layer, which can significantly reduce the surface adsorption of the incompatible bulk polymer, thereby promoting its slippage in the mold, and effectively improving the quality and output of the processed product.

[0028] 2. When the processing aid of the present invention is used in the processing of polyolefins, it has the advantages of small addition amount, short effective time, good viscosity reduction effect, and effective improvement of product gloss. In addition, the modified and catalytic oligomers are used to improve 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 the final product will not be discolored.

[0029] 3. When preparing the processing aid, the present invention first mixes the antioxidant with the molten oligomer A to react under certain conditions to obtain a first component, then granulates the other components to obtain a second component, and finally mixes the first component and the second component. Through the above operations, the antioxidant is first used to graft the oligomer A, which greatly improves the heat resistance of the oligomer A, and the surface of the modified oligomer A has a certain polar functional group, which can effectively improve the lubricity of the product.

[0030] 4. In the preparation of the second component, the present invention adds the organosilicon polymer in batches, performs granulation multiple times, and grafts polar functional groups multiple times on the end or side chain of the main chain of the oligomer B, so that the prepared polymer processing aid has a strong affinity with the metal surface of the die head, effectively forming a stable dynamic lubrication layer, thereby improving the pressure drop and output of the product during the processing and the quality of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0032] Figure 1 It is the melting pressure of the sample in the application example. DETAILED DESCRIPTION

[0033] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0034] In order 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, rather than limiting the claims of the present invention.

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

[0036] Example 1

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

[0038] S1. Add 10 g of polyethylene glycol (molecular weight 5000) into a three-necked flask, heat at 80° C. to a molten state, slowly add 0.5 g of trinonylphenyl phosphite, continue heating and stirring to react for 20 min to obtain a melt, and powderize in a powder spraying tower at 80° C. to obtain a first component;

[0039] S2, 100g LLDPE (MI: 10), 100g methylvinyl polysiloxane (molecular weight of 500,000), and 1g catalyst maleic anhydride grafting agent are melt-reacted and granulated at 180°C to obtain a pellet product, and then the pellet product and 100g methylvinyl polysiloxane (molecular weight of 500,000) are melt-reacted and granulated for the second time at 180°C;

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

[0041] Example 2

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

[0043] S1. Add 10 g of polyethylene glycol (molecular weight 5000) into a three-necked flask, heat at 100° C. to a molten state, slowly add 0.5 g of trinonylphenyl phosphite, continue heating and stirring to react for 20 min to obtain a melt, and powderize in a powder spraying tower at 90° C. to obtain a particulate first component;

[0044] S2, 100g LLDPE (MI: 10), 100g methylvinyl polysiloxane (molecular weight 600,000), 1g catalyst maleic anhydride grafting agent, melt reaction granulation at 190°C to obtain a pellet product, the pellet product and 100g methylvinyl polysiloxane (molecular weight 600,000) are subjected to secondary melt reaction granulation at 190°C to obtain a 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 comprises the following steps:

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

[0049] S2, 100g copolymerized polypropylene (MI: 15), 100g methylvinyl polysiloxane (molecular weight 1 million), and 1g catalyst maleic anhydride grafting agent are melt-reacted and granulated at 190°C to obtain a pellet product, and the pellet product and 200g methylvinyl polysiloxane (molecular weight 900,000) are melt-reacted and granulated for the second time at 190°C to obtain a 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 comprises the following steps:

[0053] S1. Add 10 g of polyethylene glycol (molecular weight 5000) into a three-necked flask, heat at 100° C. to a molten state, slowly add 0.5 g of tris(2,4-di-tert-butylphenyl)phosphite, continue heating and stirring to react for 20 min to obtain a melt, and perform powdering treatment in a powder spraying tower at 90° C. to obtain a particulate first component;

[0054] S2, 100g copolymerized polypropylene (MI: 15), 100g hydroxy polysiloxane (molecular weight 1 million), and 1g catalyst organic peroxide crosslinking agent are melt-reacted and granulated at 190°C to obtain a pellet product, and then the above pellet product and 100g methyl vinyl polysiloxane (molecular weight 900,000) are melt-reacted and granulated at 190°C to obtain a 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 comprises the following steps:

[0058] S1. Add 10 g of polyethylene glycol (molecular weight 5000) into a three-necked flask, heat at 100° C. to a molten state, slowly add 0.5 g of pentaerythritol tetrakis (3-(3,5-di-tert-butyl-4-hydroxyphenol) propionate), continue heating and stirring to react for 20 min to obtain a melt, and perform powderization treatment in a powder spraying tower at 90° C. to obtain a particulate first component;

[0059] S2, 100g copolymerized polypropylene (MI: 15), 100g methyl vinyl polysiloxane (molecular weight 900,000), and 0.5g catalyst organic peroxide crosslinking agent are melt-reacted and granulated at 190°C to obtain a pellet product, and then the above pellet product and 100g vinyl polysiloxane (molecular weight 900,000) are melt-reacted and granulated at 190°C to obtain a 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 comprises the following steps:

[0063] S1. Add 10 g of polyethylene glycol (molecular weight 5000) into a three-necked flask, heat at 100° C. to a molten state, slowly add 0.5 g of pentaerythritol tetrakis (3-(3,5-di-tert-butyl-4-hydroxyphenol) propionate) as an antioxidant, continue heating and stirring to react for 20 min to obtain a melt, and perform powderization treatment at 90° C. in a powder spraying tower to obtain a particulate first component;

[0064] S2, 100g copolymerized polypropylene (MI: 15), 100g methylvinyl polysiloxane (molecular weight 900,000), and 0.5g catalyst organic peroxide crosslinking agent are melt-reacted and granulated at 190°C to obtain a pellet product, and then the above pellet product and 200g hydroxy polysiloxane (molecular weight 1,000,000) are melt-reacted and granulated at 190°C to obtain a 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 are further described below with reference to Example 1 and in combination with the following comparative examples.

[0067] Comparative Example 1

[0068] Commercially available perfluorinated PPA.

[0069] Comparative Example 2

[0070] 30wt% fluorine-containing PPA is commercially available.

[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 comprises the following steps:

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

[0076] S2, 100g LLDPE (MI: 10), 200g methylvinyl polysiloxane (molecular weight of 500,000) (molecular weight of 1,000,000) and 1g catalyst maleic anhydride grafting agent are melt-reacted and granulated at 180°C to obtain a second component;

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

[0078] Comparative Example 5

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

[0080] S1. Add 10 g of polyethylene glycol (molecular weight 5000) into a three-necked flask, heat at 80° C. to a molten state, slowly add 0.5 g of trinonylphenyl phosphite, continue heating and stirring to react for 20 min to obtain a melt, and powderize in a powder spraying tower at 80° C. to obtain a first component;

[0081] S2. The first component prepared above, 100g LLDPE (MI: 10), 100g methyl vinyl polysiloxane (molecular weight of 500,000), and 1g catalyst maleic anhydride grafting agent are subjected to melt reaction granulation at 180°C to obtain a granular product, and then the granular product and 100g methyl vinyl polysiloxane (molecular weight of 500,000) are subjected to a secondary melt reaction granulation at 180°C to obtain a processing aid.

[0082] Application Example 1

[0083] The processing aids in the above Examples 1-6 and Comparative Examples 1-5 and mLLDPE with an MI of 1 were extruded by a twin screw extruder (L / D of 44:1) at a temperature of 190° C. to prepare masterbatches, wherein the content of the processing aid in the masterbatches was 5wt%. The above masterbatches were mixed with mLLDPE with an MI of 1 at a mass ratio of 0.01:1, and samples were prepared in a capillary rheometer at a temperature of 190° C., which were respectively recorded as Sample 1, Sample 2, Sample 3, Sample 4, Sample 5, Comparative Sample 1, Comparative Sample 2, Comparative Sample 3, Comparative Sample 4, Comparative Sample 5, and Sample 6, wherein Sample 0 was a pure mLLDPE material with an MI of 1.

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

[0085] 1. Use a capillary rheometer to test the gradual disappearance of melt fracture of the above samples at a constant shear rate (20r / min). Specifically, in this test, a capillary rheometer (aspect ratio 25:1, die 1mm, temperature 180°C) was used to extrude the sample and observe the surface melt fracture and melt pressure with an optical microscope. Each time before switching the sample, clean it with a cleaning material, then use pure mLLDPE material to repeat the same result of sample 0 before continuing to the next sample. The test results are shown in Tables 1 and Figure 1 shown.

[0086] Table 1

[0087]

[0088]

[0089] From the results in Table 1, it can be seen that from the perspective of the time to eliminate melt fracture and appearance, the surface morphology of samples 1-6 and comparative sample 1 gradually improved, stabilized at 1000s, and melt fracture was completely eliminated. Therefore, the semi-film forming property at the die head is good, and a good dynamic lubrication layer can be formed, which effectively improves the processing quality of the product.

[0090] from Figure 1 It can be seen that the melt pressure of the sample shows a downward trend with time, and tends to be balanced after 40 minutes, which can effectively improve the processing output.

[0091] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. An environmentally friendly processing aid for polyolefins, characterized in that: The method comprises a first component and a second component, wherein the first component comprises an antioxidant-modified oligomer A, and the second component is prepared by extrusion granulation of an oligomer B, an organosilicon polymer and a catalyst; In parts by weight, the dosage of each component is: 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.

2. The environmentally friendly processing aid for polyolefins according to claim 1, characterized in that: The chemical formula of the oligomer A is as follows: Wherein, n is a natural number between 20 and 60.

3. The environmentally friendly processing aid for polyolefins according to claim 1, characterized in that: The antioxidant comprises at least one of aromatic amine antioxidants, hindered phenol antioxidants, thiodipropionate, phosphite, polyphosphate, thioether antioxidants, and thiophenol antioxidants; And / or the oligomer B includes at least one of polyethylene, polypropylene, hyperbranched polyethylene, and hyperbranched polypropylene.

4. The environmentally friendly processing aid for polyolefins according to claim 1, characterized in that: The organic silicon polymer comprises at least one of organic silicon raw rubber and hyperbranched organic silicon resin; the organic silicon raw rubber comprises at least one of methyl vinyl polysiloxane, methyl polysiloxane, vinyl polysiloxane, hydroxy vinyl polysiloxane, hydroxy polysiloxane, phenyl vinyl polysiloxane, phenyl polysiloxane and amino polysiloxane.

5. The environmentally friendly processing aid for polyolefins according to claim 1, characterized in that: The catalyst comprises at least one of dibutyltin dilaurate, an organic peroxide crosslinking agent, and a maleic anhydride grafting agent.

6. The method for preparing an environmentally friendly processing aid for polyolefins according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) heating oligomer A to a molten state; (2) slowly adding an antioxidant to the above system, stirring and reacting to obtain a melt; (3) spray granulating the melt to obtain a first component; (4) Adding oligomer B, part of the organosilicon polymer, and the catalyst into a granulator for primary granulation, and then adding the remaining organosilicon polymer for secondary granulation to obtain the second component. (5) The first component and the second component are mixed to obtain an environmentally friendly processing aid for polyolefins.

7. The method for preparing an environmentally friendly processing aid for polyolefins according to claim 6, characterized in that: In step (1), the temperature of heating to the molten state is 80-100°C.

8. The method for preparing an environmentally friendly processing aid for polyolefins according to claim 6, characterized in that: In step (2), the stirring reaction temperature is 80-100° C. and the time is 5-30 min.

9. The method for preparing an environmentally friendly processing aid for polyolefins according to claim 6, characterized in that: In step (4), the mass ratio of the partial organosilicon polymer to the remaining organosilicon polymer is 1:

1.

10. The method for preparing an environmentally friendly processing aid for polyolefins according to claim 6, characterized in that: In step (4), the temperature of the primary granulation and the secondary granulation is 130°C-200°C.

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