Polyolefin grafted maleic anhydride compatilizer and preparation method thereof

Abstract

The invention discloses a polyolefin grafted maleic anhydride compatilizer and a preparation method thereof, the polyolefin grafted maleic anhydride compatilizer takes maleic anhydride as a grafting monomer, and the polyolefin grafted maleic anhydride compatilizer comprises the following raw materials: polyolefin, the grafting monomer and an initiator; the polyolefin is a polyolefin elastomer, high-density polyethylene, low-density polyethylene or linear low-density polyethylene. The polyolefin grafted maleic anhydride compatilizer can overcome the problem that the processing application range is limited due to low grafting rate and grafting efficiency in the prior art, and has the characteristics of high grafting rate and high grafting efficiency at the same time.

Description

Technical Field

[0001] This invention belongs to the field of polymer modification technology, specifically relating to a polyolefin grafted maleic anhydride compatibilizer and its preparation method. Background Technology

[0002] Blending modification refers to the common method of mixing two or more polymers, or one polymer with fibers or inorganic fillers, to improve polymer performance or expand the range of polymer applications. Based on whether there are chemical bonds, blending modification is divided into physical blending and chemical blending. Physical blending, such as melt blending, generally has poor effects and it is difficult to achieve significant improvements in polymer structure and properties. In chemical blending, the polarity difference between the blending raw materials is usually large, which leads to poor compatibility between them. Introducing compatibilizers is currently an effective means to increase the interfacial bonding force between blending raw materials and improve the compatibility between blending raw materials with different properties.

[0003] Compatibilizers are additives that improve the compatibility between two incompatible polymers by forming covalent or hydrogen bonds at the interface of raw material molecules through chemical reactions. They typically possess the following characteristics: 1. Their molecular structure contains groups with chemical structures similar to both polymers, allowing them to form chemical bonds or physical interactions, acting as a bridge; 2. They contain groups capable of reacting with both polymers, such as carboxyl, hydroxyl, and amino groups, enabling the formation of covalent bonds at the interface through chemical reactions, thus enhancing the bonding force between the two phases; 3. The molecular weight and polarity of the compatibilizer are usually between that of the two polymers, facilitating its enrichment and diffusion at the interface and improving compatibility; 4. The amount of compatibilizer added is generally low, typically between 1-5%, as excessive addition may cause phase separation or reduce mechanical properties. Common compatibilizers include graft copolymers, block copolymers, and reactive compatibilizers. Studies have shown that molecules with these configurations can significantly improve the compatibility, mechanical properties, and thermal stability of polymer blends.

[0004] The rational selection and use of compatibilizers are key to improving the performance of polymer blends. Currently, maleic anhydride grafted onto polyolefins is the most widely used and mature system in graft copolymers. However, the amount of compatibilizer and the grafting rate in the blend system have a significant impact on the overall performance of the material. Currently, the maleic anhydride grafting rate in commercially available polyolefin-grafted maleic anhydride compatibilizers is generally around 0.5%, which is relatively low. Patent application 201610609134.2 discloses a method for obtaining high grafting rate polypropylene grafted with maleic anhydride based on melt free radical grafting reaction. This method involves a two-step process: first, styrene is grafted onto polypropylene, and then maleic anhydride is introduced for secondary grafting to obtain a high grafting rate product. However, the polypropylene grafted with maleic anhydride obtained by this method relies on the grafting of styrene to inhibit free radical chain scission of polymer molecules, and it still has the drawbacks of low grafting efficiency and the need for the preparation process to be carried out under strict conditions such as an inert atmosphere. Providing a polyolefin-grafted maleic anhydride compatibilizer with high grafting rate and efficiency as well as mild preparation conditions is an effective means to solve the above problems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a polyolefin grafted maleic anhydride compatibilizer and its preparation method to overcome the problem that the low grafting rate and grafting efficiency in the prior art leads to the limitation of processing and application range. The polyolefin grafted maleic anhydride compatibilizer of the present invention has the characteristics of high grafting rate and high grafting efficiency.

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

[0007] On the one hand, a polyolefin-grafted maleic anhydride compatibilizer is provided, using maleic anhydride as the grafting monomer, and the raw materials include polyolefin, the above-mentioned grafting monomer and initiator; the polyolefin is a polyolefin elastomer, high-density polyethylene, low-density polyethylene or linear low-density polyethylene.

[0008] Furthermore, a method for preparing the above-mentioned polyolefin-grafted maleic anhydride compatibilizer is provided, comprising:

[0009] The initiator and a portion of the polyolefin were placed in a forced-air drying oven and absorbed at 50-60°C for 6-10 hours. During the absorption process, the mixture was shaken every half hour to ensure homogeneity, thus obtaining the initiator masterbatch system.

[0010] The remaining polyolefin was added for dilution to obtain the initiator masterbatch;

[0011] The initiator masterbatch was mixed with maleic anhydride and then extruded through a twin-screw extruder to obtain a polyolefin-grafted maleic anhydride compatibilizer.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] 1. The polyolefin-grafted maleic anhydride compatibilizer of the present invention uses maleic anhydride as the grafting monomer. The raw materials include polyolefin, grafting monomer and initiator. The polyolefin is polyolefin elastomer, high-density polyethylene, low-density polyethylene or linear low-density polyethylene. The polyolefin-grafted maleic anhydride compatibilizer of the present invention has a high grafting rate and grafting efficiency, with a grafting rate >1% and a grafting efficiency >60%.

[0014] 2. This invention provides a method for preparing the above-mentioned polyolefin-grafted maleic anhydride compatibilizer. The method involves first preparing a high-concentration initiator masterbatch system, where the initiator is absorbed onto the surface of the polyolefin matrix. The initiator masterbatch is then diluted with the polyolefin matrix. The polyolefin simultaneously serves as the initiator absorption matrix, dilution system, and reaction matrix, undergoing a free radical grafting reaction with maleic anhydride. This effectively alleviates the problem of maleic anhydride monomer self-polymerization, resulting in fewer side reactions and byproducts, higher grafting rate and efficiency, and a simple, mild method that is easy to promote and apply.

[0015] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0016] Figure 1 The image shows the infrared spectrum of the initiator masterbatch from Example 1. Detailed Implementation

[0017] The technical solution will now be clearly and completely described with reference to the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0018] In the following description, the term "and / or" is used to describe the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. A and B can be singular or plural.

[0019] In the following description, the terms “including,” “containing,” “having,” and “containing” are open-ended terms, meaning that they include but are not limited to.

[0020] In the following description, the “parts” or “parts by weight” of each component can be units of weight such as grams, taels or kilograms, or the ratio of the dosage between the components. For example, it can be any mass, such as 1 part by weight can be 1g, 500g or 1kg, or 15g, 30kg, etc.

[0021] Those skilled in the art should understand that, in the following description of the embodiments of this application, the sequence of numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0022] Those skilled in the art will understand that the numerical ranges in the embodiments of this application should be understood to specifically disclose each intermediate value between the upper and lower limits of the range. Each smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this application. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0023] Unless otherwise stated, the technical / scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. While this application describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this application. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0024] The technical principle upon which this invention is based is as follows: a high-concentration initiator masterbatch system initiator absorbed on the surface of polyolefin is first prepared, and then diluted to obtain initiator masterbatch. The free radical grafting reaction of polyolefin and maleic anhydride is initiated by the above initiator masterbatch to obtain a polyolefin-grafted maleic anhydride compatibilizer with high grafting rate and grafting efficiency.

[0025] On one hand, a polyolefin-grafted maleic anhydride compatibilizer is provided, using maleic anhydride as the grafting monomer. The raw materials of the polyolefin-grafted maleic anhydride compatibilizer include polyolefin, grafting monomer, and initiator. The polyolefin is a polyolefin elastomer, high-density polyethylene, low-density polyethylene, or linear low-density polyethylene. The melt index of the polyolefin at 190°C and 2.16 kg load is 3~30 g / 10min. In some preferred embodiments, the polyolefin is a polyolefin elastomer, and the melt index of the polyolefin elastomer is 3~9 g / 10min.

[0026] Polyolefins are a class of polymeric materials polymerized from olefin monomers, including polyethylene, polypropylene, and polybutene. Polyolefin elastomers (POEs) are a class of polyolefin materials with a unique microstructure, exhibiting rubber-like elasticity, such as thermoplastic polyolefin elastomers (TPOs), combining the advantages of polyolefins with the elasticity of rubber. High-density polyethylene (HDPE) is a type of polyolefin with high crystallinity and a density greater than 0.94 g / cm³. 3Low-density polyethylene (LDPE) is a type of polyethylene with low crystallinity and a density of 0.91-0.94 g / cm³. 3 Linear low-density polyethylene (LLDPE) is a type of low-density polyethylene with a relatively regular molecular structure and a density ranging from 0.91 to 0.94 g / cm³. It possesses good flexibility and transparency. 3 It exhibits high strength and impact resistance. This invention uses polyolefin elastomer (POE), high-density polyethylene, low-density polyethylene, or linear low-density polyethylene as the matrix, and as the dispersion system and diluent for the initiator masterbatch, effectively achieving the absorption of the initiator on the surface and subsequent grafting reaction with maleic anhydride free radicals.

[0027] In some embodiments, the raw materials for the polyolefin-grafted maleic anhydride compatibilizer are polyolefin, grafting monomer, and initiator.

[0028] In this invention, the raw materials for the polyolefin-grafted maleic anhydride compatibilizer are only polyolefin, grafting monomer, and initiator.

[0029] In some embodiments, the polymer content of maleic anhydride in the raw material is 1.5~5 wt%; the polymer content of maleic anhydride = mass of maleic anhydride / mass of polyolefin. .

[0030] The present invention preferably uses a polymer content of maleic anhydride of 1.5 to 5 wt% to achieve sufficient grafting of maleic anhydride and obtain a polyolefin-grafted maleic anhydride compatibilizer with high grafting rate and grafting efficiency.

[0031] In some embodiments, the initiator is one or more of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, dicumyl peroxide, benzoyl peroxide, tert-butyl peroxide, and diisopropyl peroxide; preferably, the initiator is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

[0032] In some embodiments, the raw materials contain 1.5 to 5 parts of graft monomer and 0.06 to 0.12 parts of initiator, based on 100 parts by weight of polyolefin. Preferably, the initiator contains 0.09 to 0.11 parts.

[0033] On the other hand, a method for preparing the above-mentioned polyolefin-grafted maleic anhydride compatibilizer is provided, comprising:

[0034] The initiator and a portion of the polyolefin were placed in a forced-air drying oven and absorbed at 50-60°C for 6-10 hours. During the absorption process, the mixture was shaken every half hour to ensure homogeneity, thus obtaining the initiator masterbatch system. Since the initiator half-life is generally above 120°C, the initiator was only uniformly absorbed on the surface of the polyolefin at this temperature, and no free radical initiation reaction occurred.

[0035] The remaining polyolefin was added for dilution to obtain the initiator masterbatch;

[0036] The initiator masterbatch was mixed with maleic anhydride and extruded through a twin-screw extruder to obtain a polyolefin-grafted maleic anhydride compatibilizer. The grafted product was obtained by initiating a free radical grafting reaction between the polyolefin and maleic anhydride using an initiator.

[0037] This invention provides a method for preparing the above-mentioned olefin-grafted maleic anhydride compatibilizer, comprising first preparing a high-concentration initiator masterbatch system, wherein the initiator is absorbed on the surface of a polyolefin matrix, and then the initiator masterbatch is obtained by diluting the polyolefin matrix. Then, the polyolefin matrix with the initiator absorbed is dispersed in the same matrix and undergoes a free radical grafting reaction with maleic anhydride. This method can effectively promote the forward reaction, improve the grafting efficiency and grafting rate of maleic anhydride, and also effectively improve the utilization rate of raw materials.

[0038] In some embodiments, the mass ratio of polyolefin to all polyolefin used in the formulation of the initiator masterbatch system is 4 to 6:100.

[0039] In some embodiments, the polymer content of maleic anhydride is 1.5~5 wt%, and the polymer content of maleic anhydride = mass of maleic anhydride / mass of polyolefin. The initiator masterbatch contains 0.06~0.12 wt% of initiator, preferably 0.09~0.11 wt%, and the initiator masterbatch contains the initiator mass / polyolefin mass.

[0040] In some embodiments, the twin-screw extruder has 11 extrusion stages, the reaction temperature during extrusion is 140~230℃, the temperature increase gradient between adjacent stages is 0~25℃, the screw speed is 150~500 r / min, the length-to-diameter ratio is 40~50:1, and the feed rate is 5~10 kg / h; preferably, the reaction temperature during extrusion is 140~210℃, the screw speed is 200~250 r / min, the length-to-diameter ratio is 40:1, and the feed rate is 5~6.5 kg / h.

[0041] The polyolefin-grafted maleic anhydride compatibilizer obtained by the above preparation method of the present invention can improve the grafting rate and grafting efficiency, ensure a high maleic anhydride compatibilizing component, and broaden the scope of subsequent applications.

[0042] Prior to the application for this invention, a series of experiments were conducted. Some of the experimental results are listed below to provide a more detailed description of the invention. The following is a detailed description in conjunction with the embodiments.

[0043] Example 1

[0044] This embodiment provides a polyolefin grafted maleic anhydride compatibilizer, the raw materials of which only include initiator masterbatch (the raw materials of the initiator masterbatch are polyolefin elastomer and initiator, the mass ratio of initiator to polyolefin elastomer is 0.09:100) and maleic anhydride, the mass ratio of maleic anhydride to polyolefin elastomer is 1.53:100.

[0045] The initiator is 2,5-dimethyl-2,5-bis-(tert-butylperoxy)hexane;

[0046] The polyolefin elastomer is Dow Chemical ENGAGE™ PV 8660 POE; the melt index of the polyolefin elastomer at 190°C and 2.16 kg load is 3~9 g / 10min, and the melt index of the polyolefin elastomer is determined based on GB / T 3682.1-2018.

[0047] This embodiment also provides a method for preparing the above-mentioned polyolefin grafted maleic anhydride compatibilizer, including:

[0048] Add 4.5 parts by weight of the above polyolefin elastomer and 0.09 parts by weight of the above initiator to a fluorinated bottle, and transfer it to a 60°C drying oven for absorption for 6 hours. Shake once every 30 minutes during the absorption process to obtain a 2 wt% high concentration initiator masterbatch system.

[0049] The high-concentration initiator masterbatch system was mixed with 95.5 parts by weight of polyolefin elastomer, i.e., diluted to 0.09 wt% with the above polyolefin elastomer to obtain the initiator masterbatch;

[0050] The above-mentioned initiator masterbatch was mixed with 1.53 parts by weight of maleic anhydride and fed into a twin-screw extruder through a feeder for reactive extrusion granulation to obtain a polyolefin grafted maleic anhydride compatibilizer.

[0051] The extrusion process of the twin-screw extruder is divided into eleven stages, and the twin-screw extruder is configured as follows:

[0052] The temperature ranges as follows: Section 1: 140℃, Section 2: 150℃, Section 3: 150℃, Section 4: 165℃, Section 5: 190℃, Section 6: 200℃, Section 7: 200℃, Section 8: 200℃, Section 9: 200℃, Section 10: 210℃, Section 11: 210℃. The length-to-diameter ratio is 40:1, the main screw speed is 250 r / min, the feed rate is 5 kg / h, and the vacuum pressure is 0.05 MPa. The feed rate is based on the conveying capacity; a feed rate of 5 kg / h means that 5 kg of product can be harvested in 1 hour.

[0053] Example 2

[0054] This embodiment provides a polyolefin grafted maleic anhydride compatibilizer, the raw materials of which only include initiator masterbatch (the raw materials of the initiator masterbatch are polyolefin elastomer and initiator, the mass ratio of the initiator to the polyolefin elastomer is 0.11:100) and maleic anhydride, the mass ratio of the maleic anhydride to the polyolefin elastomer is 1.82:100.

[0055] This embodiment provides a method for preparing the above-mentioned polyolefin grafted maleic anhydride compatibilizer, which is the same as that in Example 1, except that:

[0056] In the initiator masterbatch system, the mass of polyolefin elastomer is 5.5 parts by weight and the mass of initiator is 0.11 parts by weight;

[0057] The mass of the polyolefin elastomer used for dilution is 94.5 parts by weight;

[0058] The mass of maleic anhydride is 1.82 parts by weight.

[0059] Example 3

[0060] This embodiment provides a polyolefin-grafted maleic anhydride compatibilizer. The raw materials include only initiator masterbatch (the raw materials of the initiator masterbatch are high-density polyethylene and initiator, and the mass ratio of initiator to high-density polyethylene is 0.09:100) and maleic anhydride, and the mass ratio of maleic anhydride to high-density polyethylene is 1.56:100; the high-density polyethylene is Fujian United DMDA8008, with a melt index of 8.2 g / 10min, and the test conditions are 190℃ and 2.16 kg;

[0061] This embodiment provides a method for preparing the above-mentioned polyolefin grafted maleic anhydride compatibilizer, which is the same as in Example 1, except that high-density polyethylene is used instead of polyolefin elastomer:

[0062] Specifically, in the initiator masterbatch system, the mass of the high-density polyethylene is 4.5 parts by weight, and the mass of the initiator is 0.09 parts by weight.

[0063] The mass of high-density polyethylene used for dilution is 95.5 parts by weight;

[0064] The mass of maleic anhydride is 1.56 parts by weight.

[0065] Example 4

[0066] This embodiment examines the effect of initiator masterbatch on product performance and provides a polyolefin-grafted maleic anhydride compatibilizer and its preparation method. The polyolefin-grafted maleic anhydride compatibilizer is the same as in Example 1, except that low-density polyethylene is used instead of polyolefin elastomer. That is, the raw materials only include initiator masterbatch (the raw materials of the initiator masterbatch are low-density polyethylene and initiator, and the mass ratio of initiator to low-density polyethylene is 0.09:100) and maleic anhydride, and the mass ratio of maleic anhydride to low-density polyethylene is 1.56:100; the low-density polyethylene is Dow Chemical AGILITY™ EC 7000, with a melt index of 3.9 g / 10 min, and the test conditions are 190°C / 2.16 kg.

[0067] The preparation method is the same as in Example 1, except that:

[0068] Replace the polyolefin elastomer with the aforementioned low-density polyethylene;

[0069] In the initiator masterbatch system, the mass of low-density polyethylene is 4.5 parts by weight and the mass of initiator is 0.09 parts by weight;

[0070] The mass of low-density polyethylene used for dilution is 95.5 parts by weight;

[0071] The mass of maleic anhydride is 1.56 parts by weight.

[0072] Comparative Example 1

[0073] This comparative study examines the effect of feed rate on product performance and provides a polyolefin-grafted maleic anhydride compatibilizer and its preparation method. The raw materials for the polyolefin-grafted maleic anhydride are the same as those in Example 1, and the preparation method of the polyolefin-grafted maleic anhydride compatibilizer is the same as that in Example 1, except that the feed rate is 6.5 kg / h.

[0074] Comparative Example 2

[0075] This comparative study investigates the effect of the polymer content of maleic anhydride on the product performance, and provides a polyolefin-grafted maleic anhydride compatibilizer and its preparation method. The polyolefin-grafted maleic anhydride compatibilizer is the same as that in Example 1, except that the raw materials include only initiator masterbatch (the raw materials of the initiator masterbatch are polyolefin elastomer and initiator, and the mass ratio of initiator to polyolefin elastomer is 0.06:100) and maleic anhydride, and the mass ratio of maleic anhydride to polyolefin elastomer is 1.04:100; that is, the polymer content of maleic anhydride is 1.04 / 100, and the mass percentage of initiator in the initiator masterbatch is 0.06 wt%.

[0076] The preparation method is the same as in Example 1, except that:

[0077] In the initiator masterbatch system, the mass of the above-mentioned high-density polyethylene is 3 parts by weight, and the mass of the initiator is 0.06 parts by weight;

[0078] The mass of the high-density polyethylene used for dilution is 97 parts by weight;

[0079] The mass of maleic anhydride is 1.04 parts by weight.

[0080] Comparative Example 3

[0081] This comparative study investigates the effect of the mass percentage of initiator in the initiator masterbatch on the product performance, and provides a polyolefin-grafted maleic anhydride compatibilizer and its preparation method. The polyolefin-grafted maleic anhydride compatibilizer is the same as that in Example 3, except that the raw materials include only the initiator masterbatch (the raw materials of the initiator masterbatch are high-density polyethylene and initiator, and the mass ratio of initiator to high-density polyethylene is 0.06:100) and maleic anhydride, and the mass ratio of maleic anhydride to high-density polyethylene is 1.56:100; the mass percentage of initiator in the initiator masterbatch is 0.06 wt%.

[0082] The preparation method is the same as in Example 3, except that:

[0083] In the initiator masterbatch system, the mass of high-density polyethylene is 3 parts by weight and the mass of initiator is 0.06 parts by weight;

[0084] The mass of the high-density polyethylene used for dilution is 97 parts by weight.

[0085] Comparative Example 4

[0086] This comparative example examines the effect of the mass percentage of initiator in the initiator masterbatch on the product performance, providing a polyolefin-grafted maleic anhydride compatibilizer, identical to Example 3, except that the raw materials include only initiator masterbatch (the raw materials of the initiator masterbatch are high-density polyethylene and initiator, and the mass ratio of initiator to high-density polyethylene is 0.12:100) and maleic anhydride, the mass ratio of maleic anhydride to high-density polyethylene is 1.56:100, and the mass percentage of initiator in the initiator masterbatch is 0.12 wt%.

[0087] This comparative example provides a method for preparing the above-mentioned polyolefin grafted maleic anhydride compatibilizer, which is the same as that in Example 3, except that:

[0088] In the initiator masterbatch system, the mass of high-density polyethylene is 6 parts by weight, and the mass of initiator is 0.12 parts by weight;

[0089] The mass of the high-density polyethylene used for dilution is 94 parts by weight.

[0090] Comparative Example 5

[0091] This comparative example examines the influence of the preparation process on the product performance, and provides a polyolefin-grafted maleic anhydride compatibilizer and its preparation method. The raw materials for the polyolefin-grafted maleic anhydride compatibilizer are the same as those in Example 1, and the preparation method is as follows:

[0092] The polyolefin elastomer, initiator and maleic anhydride are mixed and fed into a twin-screw extruder through a feeder for reactive extrusion granulation to obtain a polyolefin-grafted maleic anhydride compatibilizer; the extrusion process and parameter settings of the twin-screw extruder are the same as in Example 1.

[0093] Comparative Example 6

[0094] This comparative study examines the influence of the preparation process on the product performance and provides a polyolefin-grafted maleic anhydride compatibilizer and its preparation method. The raw materials of the polyolefin-grafted maleic anhydride compatibilizer include 100 parts by weight of polyolefin elastomer, 0.09 parts by weight of initiator, 1.60 parts by weight of maleic anhydride, and 1.77 parts by weight of diluent 2-butanone. The diluent is used to compensate for the defect that maleic anhydride cannot be fully dissolved due to insufficient initiator content in the blending process.

[0095] The preparation method is as follows:

[0096] Polyolefin elastomer was fed into a twin-screw extruder via a feeder. An initiator, maleic anhydride, and diluent were prepared into a mixed solution at 50°C and 200 rpm. The mixed solution was injected into the fourth barrel of the melting section of the twin-screw extruder containing the polyolefin elastomer via a metering pump, so as to react with the molten polyolefin elastomer and extrude granulate to obtain a polyolefin elastomer grafted with maleic anhydride. The extrusion process and parameter settings of the twin-screw extruder were the same as in Example 1.

[0097] Performance Evaluation

[0098] The raw material usage and performance of each embodiment and comparative example are shown in Table 1.

[0099] Table 1. Raw material consumption and performance of each embodiment and comparative example.

[0100]

[0101] MFR is the melt flow index of the product polyolefin grafted with maleic anhydride compatibilizer at 190℃ and 2.16 kg, and the test method is based on GB / T 3682.1-2018;

[0102] Gx(%) represents the maleic anhydride grafting rate of the polyolefin product grafted with maleic anhydride compatibilizer. The test method is as follows: To prevent errors caused by maleic anhydride self-polymer and unreacted monomers in the grafting rate test, the graft was purified using a Soxhlet extractor. 4 g of the graft was weighed and placed in a 300-mesh 10 cm × 10 cm filter and then placed in a Soxhlet extractor. The purification reagent was 150 ml acetone. The temperature was 80℃, the rotation speed was 300 r, and the mixture was refluxed for 24 h. Excess reagent was then dried in a vacuum drying oven. After 12 h, the purified graft was obtained. 0.5 g of the purified graft was weighed and placed in a 250 ml round-bottom flask. 60 ml xylene was added, and the mixture was refluxed for 2 h. After the graft was completely dissolved, 2 drops of acid-base indicator were added, and the solution was titrated with a KOH-ethanol solution of concentration C (mol / L). The grafting rate Gx(%) was calculated using the following formula:

[0103]

[0104] Where Gx is the grafting rate (%), V is the volume consumed in titrating the KOH-ethanol solution (ml), C is the concentration of the KOH-ethanol solution, and m is the mass of the graft being measured, which is 0.5 g.

[0105] F(%) represents the grafting efficiency, and the formula for calculating the grafting efficiency is F(%) = Gx / M.

[0106] Where Gx is the grafting rate (%); M is the polymer percentage of maleic anhydride (%).

[0107] According to Table 1, as can be seen from the comprehensive examples, the polymer percentage of maleic anhydride (polymer percentage of maleic anhydride = mass of maleic anhydride / mass of polyolefin) is... The polyolefin (which is a polyolefin elastomer, low-density polyethylene, or high-density polyethylene) contains ≥1.5 wt% (the polymer content of the maleic anhydride is 1.5~2 wt%), and the initiator masterbatch contains the following mass percentage of initiator (mass percentage of initiator in initiator masterbatch = initiator mass / polyolefin mass). The polyolefin (which is a polyolefin elastomer, low-density polyethylene, or high-density polyethylene) is 0.09~0.11 wt%, and the resulting product has a grafting rate >1% and a grafting efficiency >60%. The maleic anhydride grafting rate in the polyolefin-grafted maleic anhydride compatibilizer prepared by the method of this invention is 1.01~1.23%, and the grafting efficiency is 64.7%~74.4%. Example 1 has the best overall performance, with a maleic anhydride grafting rate of 1.14% and a grafting efficiency of 74.4%. In Examples 1 and 2, the monomer percentage of the initiator is equal (initiator monomer percentage = initiator mass / maleic anhydride mass). Compared to Example 2, the mass percentage of the initiator in the initiator masterbatch of Example 1 decreases from 0.11 wt% to 0.09 wt%, resulting in different maleic anhydride grafting rates and efficiencies. Increasing the mass percentage of the initiator in the initiator masterbatch promotes a higher grafting rate but is detrimental to improving the grafting efficiency.

[0108] The compatibilizer prepared by raw material blending, extrusion, and melt processing in Comparative Example 5 had a grafting rate of only 0.58% and a grafting efficiency of only 37.9%, which was significantly lower than the grafting rate and grafting efficiency of the compatibilizer prepared by first preparing a high-concentration initiator masterbatch, then diluting it with a polyolefin matrix, and then extruding and melting it with maleic anhydride in Comparative Example 6. The compatibilizer prepared by first solubilizing the initiator and maleic anhydride and then injecting it into a molten polyolefin matrix and then extruding it also had a grafting rate of only 0.65% and a grafting efficiency of 42.5%, which was higher than that of Comparative Example 1, but still significantly lower than the grafting performance of the compatibilizers in each example.

[0109] Compared to Example 1, the feed rate in the screw extrusion process of Comparative Example 1 was increased to 6.5 kg / h, resulting in a decrease in both grafting rate and grafting efficiency. This indicates that, under the same reaction system, the optimal feed rate in the screw extrusion process for preparing the compatibilizer in this invention is 5 kg / h, leading to a more complete initiator reaction. Compared to Comparative Example 2, Examples 1 or 2 increased the polymer content of maleic anhydride and / or the mass percentage of initiator in the initiator masterbatch, resulting in a significant increase in both the grafting rate and grafting efficiency of the corresponding compatibilizer product.

[0110] Compared with Comparative Example 3, the mass percentage of initiator in the initiator masterbatch of Comparative Example 4 and Example 3 was 0.12 wt%, 0.09%, and 0.06%, respectively. As the mass percentage of initiator in the initiator masterbatch decreased, the grafting rate and grafting efficiency showed a trend of first increasing and then decreasing. When the mass percentage of initiator in the initiator masterbatch was 0.09 wt%, the grafting rate and grafting efficiency were the highest. The reason for this may be that when the mass percentage of initiator in the initiator masterbatch is low, the amount of free radicals is insufficient, and maleic anhydride cannot be fully grafted. When the mass percentage of initiator in the initiator masterbatch is high, side reactions such as chain transfer or degradation are easily triggered.

[0111] Figure 1 The infrared spectrum of the initiator masterbatch in Example 1 shows that, compared with the infrared spectrum of the raw material polyolefin elastomer, the infrared spectrum of the initiator masterbatch is not significantly different, and no new bonds are formed. Combined with the half-life temperature of the initiator, it can be seen that the initiator of the present invention is only absorbed on the surface of the polyolefin elastomer and no chemical bonding occurs.

Claims

1. A polyolefin-grafted maleic anhydride compatibilizer, using maleic anhydride as the grafting monomer, characterized in that... The raw materials for the polyolefin-grafted maleic anhydride compatibilizer include polyolefin, grafting monomer and initiator; the polyolefin is a polyolefin elastomer, high-density polyethylene, low-density polyethylene or linear low-density polyethylene.

2. The polyolefin-grafted maleic anhydride compatibilizer according to claim 1, characterized in that, The raw materials for the polyolefin-grafted maleic anhydride compatibilizer are polyolefin, grafting monomer, and initiator.

3. The polyolefin-grafted maleic anhydride compatibilizer according to claim 1 or 2, characterized in that, The polyolefin is a polyolefin elastomer, high-density polyethylene, or low-density polyethylene.

4. The polyolefin-grafted maleic anhydride compatibilizer according to claim 1 or 2, characterized in that, In the raw materials, the polymer content of maleic anhydride is 1.5~5 wt%.

5. The polyolefin-grafted maleic anhydride compatibilizer according to claim 1 or 2, characterized in that, The initiator is one or more of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, dicumyl peroxide, benzoyl peroxide, tert-butyl peroxide, and diisopropyl peroxide.

6. The polyolefin-grafted maleic anhydride compatibilizer according to claim 1 or 2, characterized in that, Based on 100 parts by weight of polyolefin, maleic anhydride is 1.5 to 5 parts and initiator is 0.06 to 0.12 parts.

7. A method for preparing the polyolefin-grafted maleic anhydride compatibilizer as described in claim 1 or 2, characterized in that, include: The initiator and a portion of the polyolefin were placed in a forced-air drying oven and absorbed at 50-60°C for 6-10 hours. During the absorption process, the mixture was shaken every half hour to ensure homogeneity, thus obtaining the initiator masterbatch system. The remaining polyolefin was added for dilution to obtain the initiator masterbatch; The initiator masterbatch was mixed with maleic anhydride and then extruded through a twin-screw extruder to obtain a polyolefin-grafted maleic anhydride compatibilizer.

8. The method according to claim 7, characterized in that, The twin-screw extruder has 11 extrusion sections, the reaction temperature during extrusion is 140~230℃, the temperature increase gradient between adjacent sections is 0~25℃, the screw speed is 150~500r / min, the length-to-diameter ratio is 40~50:1, and the feed rate is 5~10 kg / h.

9. The method according to claim 7, characterized in that, The mass ratio of polyolefin to all polyolefins used in the preparation of the initiator masterbatch system is 4~6:

100.

10. The method according to claim 7, characterized in that, The polymer content of maleic anhydride is 1.5~5 wt%, and the initiator content in the initiator masterbatch is 0.06~0.12 wt%.

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