Preparation method and application of dynamic covalent bond compatibilized thermoplastic blend

Abstract

The invention provides a preparation method and application of a dynamic covalent bond compatibilized thermoplastic blend, and relates to the technical field of high polymer materials, the method comprises the following steps: (1) carrying out melt blending on at least two incompatible or partially compatible thermoplastic polymer blends, a reaction reagent containing acid anhydride or carboxyl groups, an initiator and an auxiliary agent according to a mass ratio of 100: (0.5-12): (0.05-1.5): (0.5-12), carrying out reactive extrusion to obtain a grafted modified material; and (2) carrying out melt blending on the grafted modified material, a cross-linking agent containing an epoxy group or a hydroxyl group and a catalyst according to a mass ratio of 100: (1-20): (0.1-5), and carrying out reactive extrusion to form a dynamic covalent bond network so as to obtain the compatibilization blend. According to the invention, the compatibility and mechanical properties of the thermoplastic blend are improved, and the problems of high recovery cost, complex recovery technology, serious plastic pollution and the like of the waste thermoplastic plastic blend in real life are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a preparation method and application of a dynamic covalent bond-compatibilized thermoplastic blend. Background Art

[0002] Blending thermoplastic polymer materials such as polypropylene, polyethylene or ethylene-vinyl acetate copolymer is an efficient way to develop new polymer materials. Compared with developing new polymers through monomer synthesis, blending technology based on existing thermoplastic polymer materials can not only significantly reduce R&D costs and time investment, but also achieve precise design of material properties by controlling the proportion of components. However, since these polymer systems are generally thermodynamically incompatible, they lead to problems such as weak interfacial bonding and phase separation, which seriously restrict the performance of the blended materials. Therefore, the development of efficient blending and compatibilization technology for thermoplastic polymer materials has always been a scientific and engineering problem that needs to be broken through in the field of polymer materials.

[0003] On the other hand, with the rapid development of the global plastics industry, thermoplastic polymer materials are widely used in packaging, construction, electronics and electrical, medical and health, agriculture, and the automotive industry due to their abundant raw material sources, low cost, excellent processing performance, and outstanding comprehensive performance. However, a large number of thermoplastic polymer products form a huge amount of waste plastics after completing their use cycle. If they are directly recycled, they will age during use, resulting in a significant decrease in mechanical properties after melt regeneration. Moreover, in actual recycling scenarios, they are usually mixtures of multiple thermoplastic polymer materials. Due to differences in molecular structure, they lack compatibility, and phase separation and poor interfacial adhesion are prone to occur after blending, thereby weakening the solid-state mechanical properties. Even polyolefins with similar chemical compositions may still show incompatibility after melt blending. For example, adding 8wt% high-density polyethylene to homopolymer polypropylene will lead to incompatibility of the blend, making the material brittle and reducing its application value. Therefore, there is an urgent need to provide a method for preparing and applying thermoplastic blends with dynamic covalent bond compatibilization. Summary of the Invention

[0004] The embodiments of the present invention provide a method for preparing and applying a thermoplastic blend with dynamic covalent bond compatibilization. The method improves the compatibility and mechanical properties of the thermoplastic blend, and solves the problems of high recycling costs, complex recycling technologies, and serious plastic pollution caused by waste thermoplastic blends in real life.

[0005] In a first aspect, the present invention provides a method for preparing a thermoplastic blend with dynamic covalent bond compatibilization, characterized by comprising:

[0006] (1) melt blending at least two incompatible or partially compatible thermoplastic polymer blends, a reaction reagent containing anhydride or carboxyl groups, an initiator, and an auxiliary agent in a mass ratio of 100:(0.5-12):(0.05-1.5):(0.5-12), and obtaining a grafted modified material by reactive extrusion;

[0007] (2) melt-blending the grafted modified material with a cross-linking agent containing epoxy or hydroxyl groups and a catalyst in a mass ratio of 100:(1-20):(0.1-5), forming a dynamic covalent bond network through reactive extrusion, and obtaining a compatibilized blend.

[0008] Preferably, the thermoplastic polymer blend is one of the following blending systems:

[0009] a: A blend of polypropylene and polyethylene, wherein:

[0010] The mass ratio of the polypropylene to the polypropylene is 5:95 to 95:5;

[0011] b: Blends of polypropylene and polyolefin elastomers, wherein:

[0012] The content of the polyolefin elastomer in the blend is 5-40wt%;

[0013] c: Polar / non-polar blend, where:

[0014] The polar / non-polar blend is a blend of ethylene-vinyl acetate copolymer and polyethylene in a mass ratio of 10:90 to 90:10 or a blend of ethylene-vinyl alcohol copolymer and polyethylene in a mass ratio of 5:95 to 95:5;

[0015] d: Blends of polystyrene with polypropylene and / or polyethylene, wherein:

[0016] The mass ratio of the polystyrene to the polypropylene and / or the polyethylene is 5:95 to 95:5;

[0017] Wherein, the polypropylene is homopolymer polypropylene or copolymer polypropylene;

[0018] The polyethylene is high-density polyethylene, low-density polyethylene or linear low-density polyethylene;

[0019] The polystyrene is general-purpose polystyrene or high-impact polystyrene.

[0020] More preferably, in any combination of items a to d above, the blend may contain ≤50 wt% of recycled or regenerated materials of the corresponding thermoplastic polymer, and the impurity content may be ≤5 wt%.

[0021] Preferably, the reaction reagent is C4-C 20Aliphatic or aromatic dianhydrides and dicarboxylic acids.

[0022] More preferably, the reaction reagent is one or more of maleic anhydride, itaconic anhydride, nadic anhydride or itaconic acid.

[0023] Preferably, the initiator is an organic peroxide or an azo compound.

[0024] More preferably, the initiator is one or more of azobisisobutyronitrile, dicumyl peroxide, benzoyl peroxide or tert-butyl hydroperoxide.

[0025] Preferably, the auxiliary agent is a free radical stabilizer or a reaction accelerator.

[0026] More preferably, the auxiliary agent is one or more of divinylbenzene, styrene or dimethylaniline.

[0027] Preferably, the cross-linking agent is a compound that can undergo epoxy ring-opening esterification or alcohol ester exchange reaction with anhydride / carboxyl group.

[0028] More preferably, the crosslinking agent is one or more of bisphenol A diglycidyl ether, polyethylene glycol diglycidyl ether, bisphenol F diglycidyl ether, 1,4-butanediol diglycidyl ether, trimethylolpropane, 1,4-butanediol, epoxidized soybean oil or epoxidized castor oil.

[0029] Preferably, the catalyst is a compound capable of promoting epoxy-anhydride ring-opening reaction and / or transesterification reaction.

[0030] More preferably, the catalyst is one or more of stannous octoate, zinc acetate, zinc acetylacetonate, 1,5,7-triazabicyclo[4.4.0]dec-5-ene or triphenylphosphine.

[0031] Preferably, the reaction extrusion process window of step (1) is: screw speed 40-240 rpm; melt temperature 130-280°C;

[0032] Preferably, the reaction extrusion process window of step (2) is: screw speed 60-350 rpm; melt temperature 130-300°C.

[0033] In a second aspect, the present invention provides a dynamically covalently compatibilized thermoplastic blend prepared by any of the methods described in the first aspect, wherein the elongation at break is ≥80%.

[0034] In a third aspect, the present invention provides an application of the dynamically covalently compatibilized thermoplastic blend according to the second aspect, for use in manufacturing packaging films, automotive interiors, electronic and electrical housings, or high-value recycled plastic products.

[0035] Compared with the prior art, the present invention has at least the following beneficial effects:

[0036] The present invention significantly improves the compatibility of the thermoplastic blend system by grafting and modifying at least two incompatible or partially compatible thermoplastic polymer blends, reaction reagents containing anhydride or carboxyl groups, initiators, and auxiliary agents, and then implementing dynamic covalent crosslinking through a crosslinking agent containing epoxy or hydroxyl groups. In this way, not only the mechanical properties of the thermoplastic blend system are effectively improved, but also its reprocessability is greatly enhanced, so that the recycled thermoplastic blend can be successfully prepared into a material suitable for daily use, realizing the recycling of waste plastics. In the present invention, the elongation at break of the prepared dynamically covalently compatibilized thermoplastic blend is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 This is a flow chart of a method for preparing a thermoplastic blend with dynamic covalent bond compatibilization provided by the present invention;

[0039] Figure 2 DMA curves of a blend of homopolypropylene and high-density polyethylene with a mass ratio of 70:30 before and after compatibilization provided by one embodiment of the present invention;

[0040] Figure 3 The tensile stress-strain curves of a blend of homopolypropylene and high-density polyethylene in a mass ratio of 70:30 before and after compatibilization are provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0042] like Figure 1 As shown, the present invention provides a method for preparing a thermoplastic blend with dynamic covalent bond compatibilization, the preparation method comprising the following steps:

[0043] (1) melt blending at least two incompatible or partially compatible thermoplastic polymer blends, a reaction reagent containing anhydride or carboxyl groups, an initiator, and an auxiliary agent in a mass ratio of 100:(0.5-12):(0.05-1.5):(0.5-12), and obtaining a grafted modified material by reactive extrusion;

[0044] (2) melt-blending the grafted modified material with a cross-linking agent containing epoxy or hydroxyl groups and a catalyst in a mass ratio of 100:(1-20):(0.1-5), forming a dynamic covalent bond network through reactive extrusion, and obtaining a compatibilized blend.

[0045] In the present invention, the present invention significantly improves the compatibility of the thermoplastic blend system by grafting and modifying a thermoplastic polymer blend comprising at least two incompatible or partially compatible materials, a reaction reagent containing an anhydride or carboxyl group, an initiator, and an auxiliary agent, and then implementing dynamic covalent crosslinking through a crosslinking agent containing an epoxy group or a hydroxyl group. In this way, not only the mechanical properties of the thermoplastic blend system are effectively improved, but also its reprocessability is greatly enhanced, so that the recycled thermoplastic blend can be successfully prepared into a material suitable for daily use, realizing the recycling of waste plastics. In the present invention, the elongation at break of the prepared dynamically covalently compatibilized thermoplastic blend is significantly improved.

[0046] First, a thermoplastic polymer blend comprising at least two incompatible or partially compatible polymers is grafted and modified using a reaction reagent, initiator, and auxiliary agent containing anhydride or carboxyl groups to introduce active groups. Subsequently, a cross-linking agent containing epoxy groups or hydroxyl groups is introduced into the grafted modified material, and a dynamic covalent chemical cross-linking network is constructed by epoxy ring-opening esterification or alcohol ester exchange reaction under a catalyst. This cross-linking network can break and reorganize during the processing process to connect different polymer chains, thereby effectively improving the compatibility between thermoplastic blends, reducing phase separation, and enhancing the mechanical properties of the material. Compared with traditional physical compatibilization methods, the method of the present invention can significantly improve the mechanical properties of the blend, giving it a wider range of application potential, suitable for daily use and high-performance engineering materials.

[0047] According to some preferred embodiments, the thermoplastic polymer blend is one of the following blend systems:

[0048] a: A blend of polypropylene (PP) and polyethylene (PE), wherein:

[0049] Polypropylene is homopolypropylene or copolymer polypropylene;

[0050] Polyethylene is high-density polyethylene (HDPE), low-density polyethylene (LDPE) or linear low-density polyethylene (LLDPE);

[0051] The mass ratio of polypropylene to polypropylene is 5:95 to 95:5;

[0052] b: A blend of polypropylene and polyolefin elastomer (POE), wherein:

[0053] Polypropylene is homopolypropylene or copolymer polypropylene;

[0054] The content of the polyolefin elastomer in the blend is 5-40 wt% (for example, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt% or 40 wt%);

[0055] c: Polar / non-polar blend, where:

[0056] The polar / non-polar blend is a blend of ethylene-vinyl acetate copolymer (EVA) and polyethylene in a mass ratio of 10:90 to 90:10 or a blend of ethylene-vinyl alcohol copolymer (EVOH) and polyethylene in a mass ratio of 5:95 to 95:5;

[0057] d: Blends of polystyrene (PS) with polypropylene (PP) and / or polyethylene (PE), wherein:

[0058] The polystyrene is general-purpose polystyrene (GPPS) or high-impact polystyrene (HIPS);

[0059] Polypropylene is homopolypropylene or copolymer polypropylene;

[0060] Polyethylene is high-density polyethylene (HDPE), low-density polyethylene (LDPE) or linear low-density polyethylene (LLDPE);

[0061] The mass ratio of polystyrene to polypropylene and / or polyethylene is 5:95 to 95:5.

[0062] Specifically, the mass ratio of 5:95 to 95:5 refers to any ratio of 5:95 to 95:5, for example, 5:95, 10:90, 15:85, 20:80, 25:75, 30:70, 35:65, 40:60, 45:55, 50:50, 55:45, 60:40, 65:35, 70:30, 75:25, 80:20, 85:15, 90:10 or 95:55. 5:5, etc.; a mass ratio of 10:90 to 90:10 refers to any ratio between 10:90 and 90:10, for example, it can be 10:90, 15:85, 20:80, 25:75, 30:70, 35:65, 40:60, 45:55, 50:50, 55:45, 60:40, 65:35, 70:30, 75:25, 80:20, 85:15 or 90:10, etc.

[0063] According to some more preferred embodiments, in any combination of a to d above, the blend may contain ≤50 wt% (for example, 1 wt%, 2 wt%, 4 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt% or 50 wt%) of recycled or regenerated materials of the corresponding thermoplastic polymer, and the impurity content may be ≤5 wt% (for example, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt% or 5 wt%).

[0064] Specifically, recycled or regenerated materials can be obtained from common plastic bags in life (such as shopping bags, garbage bags), food packaging (such as plastic wrap, the inner layer of milk cartons), daily necessities (such as plastic buckets, toys), agricultural mulch and industrial pipes, food containers (such as takeout boxes, bottle caps, straws), household items (such as storage boxes, washbasins), non-woven products (such as masks) and automotive parts (such as bumpers).

[0065] According to some preferred embodiments, the reaction reagent in step (1) is C4-C 20 Aliphatic or aromatic dianhydrides and dicarboxylic acids. C4-C 20 The carbon chain length is 4-20. The reaction reagent is one or more of phthalic anhydride, citraconic anhydride, fumaric anhydride, glutaric anhydride, maleic anhydride, allylsuccinic anhydride, methylisoacrylic anhydride, tetrahydrophthalic anhydride, dimethylmaleic anhydride, methacrylic anhydride, itaconic anhydride, acrylic anhydride, trimellitic anhydride, 3,3',4,4'-benzophenonetetracarboxylic anhydride, tetrachlorophthalic anhydride, acrylic anhydride, methyltetrahydrophthalic anhydride, benzoic anhydride, 4-bromo-1,8-naphthalene dicarboxylic anhydride, 1,8-naphthalene dicarboxylic anhydride, 3-nitrophthalic anhydride, 4-cyclohexene-1,2-dianhydride, nadic anhydride, tetrabromophthalic anhydride, butane-2-carboxylic acid, pentane-2-carboxylic acid, hexa-2,4-diene-1,6-carboxylic acid, 2,5-furandicarboxylic acid, and itaconic acid.

[0066] It should be noted that a plurality of types refers to a mixture of any number of types in any proportion.

[0067] According to some more preferred embodiments, the reactant is one or more of maleic anhydride, itaconic anhydride, nadic anhydride, or itaconic acid. The reactant is added in an amount of 0.5-12% (e.g., 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, or 12%) of the total mass of the thermoplastic polymer blend.

[0068] According to some preferred embodiments, the initiator in step (1) is an organic peroxide or an azo compound. The initiator is one or more of dibenzoyl peroxide, di-tert-butyl peroxide, dodecyl peroxide, diisopropyl peroxide, isopropylbenzene hydroperoxide, tert-butyl hydroperoxide, azobisisobutyronitrile, azobisisoheptanenitrile, azobiscyclohexyldicarbonitrile, 2,5-dimethyl-2,5-di-tert-butylperoxyhexane, N,N-dimethylamine, lauroyl peroxide, tert-butyl perbenzoate, tert-butyl pervalerate, methyl ethyl ketone peroxide, cyclohexanone peroxide, diethylhexyl peroxydicarbonate, diisopropyl peroxydicarbonate, and dicyclohexyl peroxydicarbonate.

[0069] According to some more preferred embodiments, the initiator is one or more of azobisisobutyronitrile, dicumyl peroxide, benzoyl peroxide, or tert-butyl hydroperoxide. The initiator is added in an amount of 0.05-1.5% (0.05%, 0.1%, 0.2%, 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, or 1.5%) of the total mass of the thermoplastic polymer blend.

[0070] According to some preferred embodiments, the auxiliary agent in step (1) is a free radical stabilizer or a reaction accelerator. The auxiliary agent is one or more of divinylbenzene, styrene, dimethylformamide, decene, α-methylstyrene, ethyl benzoate, 2,2′-bipyridine, stearamide, dimethylacetamide, N,N-diethylcinnamic acid amide, N,N-dimethylacetamide, 3-(2-furyl)acrylic acid, ethyl cinnamate, dimethylaniline, dilauryl thiodipropionate, trimethylolpropane triacrylate, 3-(2-furyl)butyl acrylate, 3-(2-thienyl)butyl acrylate, 4,4-diaminodiphenylmethane, cashew nut shell oil, triallyl isocyanurate, and 1,2-polybutadiene.

[0071] According to some more preferred embodiments, the additive is one or more of divinylbenzene, styrene, or dimethylaniline. The additive is added in an amount of 0.5-12% (e.g., 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, or 12%) of the total mass of the thermoplastic polymer blend.

[0072] In the present invention, the reaction reagent acts as a grafting monomer, and grafting is carried out through the free radicals generated by the decomposition of the initiator. Experiments have confirmed that if the amount of reaction reagent is too small, the concentration of the grafted monomer is too low, and the limited diffusion of the monomer leads to a low grafting rate, which in turn affects the subsequent reaction with the cross-linking agent and the volume-increasing effect of the blend; however, if the amount of reaction reagent is too large, it is easy to induce self-polymerization side reactions, reducing the effective grafting efficiency. If the amount of initiator is too small, the number of free radicals will be too small, and the grafting reaction will be difficult to fully proceed; however, if the amount of initiator is excessive, it will cause the thermoplastic polymer in the blend to break, triggering degradation side reactions, which will lead to poor volume-increasing effect and low mechanical properties of the prepared volume-increasing blend. Therefore, the amount of reaction reagent and initiator is limited to the above range.

[0073] In the present invention, a styrene auxiliary agent is added when the blend is grafted, so that the grafting rate is improved, which is beneficial to the next cross-linking reaction.

[0074] According to some preferred embodiments, the cross-linking agent in step (2) is a compound that can undergo epoxy ring-opening esterification or alcohol ester exchange reaction with anhydride / carboxyl. The cross-linking agent is ethylene glycol diglycidyl ether, bisphenol A diglycidyl ether, resorcinol diglycidyl ether, bisphenol F diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, 1,4-butanediol diglycidyl ether, tetrabromobisphenol A diglycidyl ether, neopentyl glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, dicyclopentadiene epoxide, 1,4-bis[(glycidyl ether)] One or more of propylene glycol, propylene glycol, butylene glycol, hexanediol, heptanediol, octanediol, diethylene glycol, triethylene glycol, pentanediol, neopentyl glycol, cyclohexanediol, benzyl alcohol, furfural diol, cyclohexanedimethanol, polyethylene glycol, polypropylene glycol, glycerol, trimethylolpropane, trimethylolethane, hexanetriol, triethanolamine, trishydroxymethylaminomethane, polycarbonate triol, epoxidized soybean oil, epoxidized castor oil, and furfural diglycidyl ether.

[0075] According to some more preferred embodiments, the crosslinking agent is one or more of bisphenol A diglycidyl ether, polyethylene glycol diglycidyl ether, bisphenol F diglycidyl ether, 1,4-butanediol diglycidyl ether, trimethylolpropane, 1,4-butanediol, epoxidized soybean oil, or epoxidized castor oil. The added amount of the cross-linking agent is 1-20% (1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5% or 20%) of the total mass of the grafted modified material.

[0076] According to some preferred embodiments, the catalyst in step (2) is a compound that can promote epoxy-anhydride ring-opening reaction and / or transesterification reaction.

[0077] According to some more preferred embodiments, the catalyst is one or more of stannous octoate, zinc acetate, zinc acetylacetonate, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, or triphenylphosphine. The amount of the catalyst added is 0.1-5% (e.g., 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%) of the total mass of the grafted modified material.

[0078] According to some preferred embodiments, in step (2): the melt blending temperature is 120-300°C (for example, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 210°C, 220°C, 225°C or 230°C), the rotation speed is 30 ~250rpm (for example, it can be 30rpm, 50rpm, 60rpm, 80rpm, 100rpm, 120rpm, 150rpm, 180rpm, 200rpm or 210rpm), and the time is 2~15min (for example, it can be 4min, 5min, 6min, 7min, 8min, 9min, 10min, 11min, 12min, 13min, 14min or 15min).

[0079] In the present invention, in a mixed system, by adding a catalyst and a cross-linking agent, an ester exchange reaction occurs so that the epoxy group in the cross-linking agent and / or the hydroxyl group and the acid anhydride and / or the carboxyl group in the mixed system after grafting produce dynamic crosslinking under the action of a catalyst, i.e., a chemical crosslinking network is constructed by ester exchange reaction, so that the polymer chains are linked together by dynamic covalent bonds, and the compatibility between components in the blend is improved to obtain a polymer blend. The blend thus prepared is between a thermosetting material and a thermoplastic material, and can be processed (i.e., produce plastic flow) at high temperatures, and can also show excellent mechanical properties at room temperatures. It should be noted that, at high temperatures, refers to the melting temperature higher than the blend.

[0080] In the present invention, experiments have confirmed that excessive crosslinking agent usage can lead to excessively high crosslink density and an overly dense crosslinked network, restricting the dynamic movement of thermoplastic polymer segments, reducing the toughness and ductility of the material, and even causing brittle fracture. Excessive crosslinking density can also inhibit the dissociation and recombination of dynamic ester bonds, limiting dynamic reversibility. However, insufficient crosslinking agent usage can lead to a loose crosslinked network structure and insufficient crosslinking due to the limited number of crosslinking points, resulting in a poor compatibilization effect and, in turn, reduced mechanical properties of the compatibilized blend.

[0081] In the present invention, the catalyst is used to play a catalytic role. If the amount of the catalyst is too small, the reaction rate will be slow; but if the amount of the catalyst is too large, too many metal ions will be introduced, which will reduce the mechanical properties of the prepared compatibilized blend.

[0082] According to some preferred embodiments, the reaction extrusion process window of step (1) is: screw speed 40-300 rpm (for example, it can be 40 rpm, 50 rpm, 60 rpm, 80 rpm, 100 rpm, 150 rpm, 200 rpm, 250 rpm or 300 rpm); melt temperature 130-280°C (for example, it can be 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 210°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C or 280°C).

[0083] According to some preferred embodiments, the reaction extrusion process window of step (2) is: screw speed 60-450 rpm (for example, 60 rpm, 80 rpm, 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm or 450 rpm); melt temperature 130-300 ° C (for example, 130 ° C, 135 ° C, 140 ° C, 145 ° C, ℃, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 210℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, 255℃, 260℃, 265℃, 270℃, 275℃, 280℃, 285℃, 290℃, 295℃ or 300℃).

[0084] In the present invention, both steps (1) and (2) do not need to be carried out in a solvent and can be completed in an internal mixer or extruder, resulting in rapid reaction and simple operation. Furthermore, no complicated synthesis steps or expensive catalysts are required for synthesizing the compatibilizer, resulting in a simpler process and better economic efficiency. Therefore, the present invention is more suitable for large-scale industrial production.

[0085] The present invention also provides a dynamic covalent bond compatibilized thermoplastic blend, the elongation at break of which is ≥80%.

[0086] The present invention also provides an application of a dynamically covalently compatibilized thermoplastic blend for manufacturing packaging films, automotive interior trims, electronic and electrical appliance housings, or high-value recycled plastic products.

[0087] In order to more clearly illustrate the technical solutions and advantages of the present invention, a preparation method and application of a thermoplastic blend with dynamic covalent bond compatibilization are described in detail below through several embodiments.

[0088] In the following examples and comparative examples, the amount of each substance is expressed in parts by mass.

[0089] Polypropylene (PP) / Polyethylene (PE) blend system

[0090] Example 1

[0091] 70 parts of homopolymer PP and 30 parts of HDPE, 3 parts of reaction reagent (maleic anhydride), 0.5 parts of initiator (diisopropyl benzene peroxide) and 2 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-190°C and reactively extruded to obtain a grafted modified material; then the grafted modified material, 8 parts of a cross-linking agent (bisphenol A diglycidyl ether) and 1 part of a catalyst (stannous octoate) are reactively extruded at 140-220°C to obtain a compatibilized PP / HDPE blend.

[0092] in, Figure 2 、 Figure 3 The DMA curves and stress-strain curves of the PP / HDPE blend before and after compatibilization are shown, respectively. PP7-PE3 represents a blend obtained by directly blending 70 parts of homopolymer PP and 30 parts of HDPE before compatibilization; PP7-PE3 after compatibilization represents the compatibilized PP / HDPE blend prepared in Example 1. Figure 2 and Figure 3 It can be found that the compatibilized blend has a "rubber platform" above the melting point, and has higher tensile strength and elongation at break.

[0093] Example 2

[0094] 50 parts of copolymerized PP (including 30 parts of recycled PP) and 50 parts of LLDPE, 5 parts of reaction reagent (itaconic anhydride), 0.8 parts of initiator (benzoyl peroxide) and 4 parts of auxiliary agent (styrene) are melt-blended at 130-170°C, and a grafted modified material is obtained by reactive extrusion; then the grafted modified material, 12 parts of cross-linking agent (polyethylene glycol diglycidyl ether) and 2 parts of catalyst (zinc acetylacetonate) are reactively extruded at 150-250°C to obtain a compatibilized copolymerized PP / LLDPE blend.

[0095] Example 3

[0096] 80 parts of homopolymer PP and 20 parts of LDPE, 8 parts of reaction reagent (nadic anhydride), 1.2 parts of initiator (azobisisobutyronitrile) and 6 parts of auxiliary agent (dimethylaniline) are melt-blended at 150-210°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material, 15 parts of a cross-linking agent (1,4-butanediol) and 3 parts of a catalyst (triphenylphosphine) are reactively extruded at 160-280°C to obtain a compatibilized homopolymer PP / LDPE blend.

[0097] Example 4

[0098] 30 parts of homopolymer PP and 70 parts of HDPE, 0.5 parts of reaction reagent (maleic anhydride), 0.05 parts of initiator (tert-butyl hydroperoxide) and 0.5 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-150°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material, 1 part of cross-linking agent (1,4-butanediol) and 0.1 parts of catalyst (zinc acetate) are reactively extruded at 130-180°C to obtain a compatibilized homopolymer PP / HDPE blend.

[0099] Example 5

[0100] 90 parts of homopolymer PP and 10 parts of LLDPE, 12 parts of reaction reagent (itaconic anhydride), 1.5 parts of initiator (diisopropylbenzene peroxide) and 12 parts of auxiliary agent (styrene) are melt-blended at 180-280°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material, 20 parts of a cross-linking agent (epoxidized soybean oil) and 5 parts of a catalyst (1,5,7-triazabicyclo[4.4.0]dec-5-ene) are reactively extruded at 190-300°C to obtain a compatibilized homopolymer PP / LLDPE blend.

[0101] Example 6

[0102] 50 parts of homopolymer PP recycled material and 50 parts of HDPE recycled material, 4 parts of reaction reagent (maleic anhydride), 0.6 parts of initiator (diisopropylbenzene peroxide) and 3 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-180°C and reactively extruded to obtain a grafted modified material; then the grafted modified material, 10 parts of a cross-linking agent (bisphenol F diglycidyl ether) and 1.5 parts of a catalyst (stannous octoate) are reactively extruded at 140-230°C to obtain a compatibilized PP / HDPE blend.

[0103] Example 7

[0104] 60 parts of homopolymer PP and 40 parts of HDPE, 2 parts of reaction reagent (maleic anhydride), 0.3 parts of initiator (benzoyl peroxide) and 1.5 parts of auxiliary agent (styrene) are melt-blended at 130-160°C and reactively extruded to obtain a grafted modified material; then the grafted modified material, 5 parts of a cross-linking agent (trimethylolpropane) and 0.5 parts of a catalyst (zinc acetylacetonate) are reactively extruded at 140-200°C to obtain a compatibilized PP / HDPE blend.

[0105] Example 8

[0106] 70 parts of homopolymer PP and 30 parts of LDPE, 10 parts of reaction reagent (maleic anhydride), 1 part of initiator (diisopropyl benzene peroxide) and 8 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-200°C and reactively extruded to obtain a grafted modified material; then the grafted modified material, 15 parts of a cross-linking agent (bisphenol A diglycidyl ether) and 2 parts of a catalyst (triphenylphosphine) are reactively extruded at 150-260°C to obtain a compatibilized PP / LDPE blend.

[0107] Example 9

[0108] 50 parts of homopolymer PP and 50 parts of LLDPE, 6 parts of reaction reagent (itaconic anhydride), 0.7 parts of initiator (benzoyl peroxide) and 5 parts of auxiliary agent (styrene) are melt-blended at 130-190°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material, 18 parts of a cross-linking agent (polyethylene glycol diglycidyl ether) and 2 parts of a catalyst (stannous octoate) are reactively extruded at 150-240°C to obtain a compatibilized PP / LLDPE blend.

[0109] Example 10

[0110] 80 parts of homopolymer PP and 20 parts of HDPE, 5 parts of reaction reagent (maleic anhydride), 0.8 parts of initiator (diisopropyl benzene peroxide) and 4 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-210°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material, 12 parts of a cross-linking agent (bisphenol A diglycidyl ether) and 2 parts of a catalyst (1 part of stannous octoate and 1 part of triphenylphosphine) are reactively extruded at 160-250°C to obtain a compatibilized PP / HDPE blend.

[0111] Comparative Example 1

[0112] 70 parts of homopolymer PP, 30 parts of HDPE, 3 parts of reaction reagent (maleic anhydride), 0.5 parts of initiator (dicumyl peroxide) and 2 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-190° C., and a grafted modified material is obtained by reactive extrusion.

[0113] Comparative Example 2

[0114] 70 parts of homopolymer PP and 30 parts of HDPE, 0.5 parts of initiator (diisopropylbenzene peroxide) and 2 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-190°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material, 8 parts of a cross-linking agent (bisphenol A diglycidyl ether) and 1 part of a catalyst (stannous octoate) are reactively extruded at 140-220°C to obtain a compatibilized PP / HDPE blend.

[0115] Comparative Example 3

[0116] 80 parts of homopolymer PP and 20 parts of LDPE, 8 parts of reaction reagent (nadic anhydride), 3 parts of initiator (azobisisobutyronitrile) and 6 parts of auxiliary agent (dimethylaniline) are melt-blended at 150-210°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material, 15 parts of a cross-linking agent (1,4-butanediol) and 3 parts of a catalyst (triphenylphosphine) are reactively extruded at 160-280°C to obtain a compatibilized homopolymer PP / LDPE blend.

[0117] Comparative Example 4

[0118] 70 parts of homopolymer PP and 30 parts of HDPE, 3 parts of reaction reagent (maleic anhydride), 0.5 parts of initiator (diisopropyl benzene peroxide) and 2 parts of auxiliary agent (divinylbenzene) are melt-blended at 120-160°C and reactively extruded to obtain a grafted modified material; then the grafted modified material, 8 parts of a cross-linking agent (bisphenol A diglycidyl ether) and 1 part of a catalyst (stannous octoate) are reactively extruded at 140-220°C to obtain a compatibilized PP / HDPE blend.

[0119] Comparative Example 5

[0120] 70 parts of homopolymer PP and 30 parts of HDPE, 3 parts of reaction reagent (maleic anhydride), 0.5 parts of initiator (diisopropyl benzene peroxide) and 2 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-190°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material and 8 parts of a cross-linking agent (bisphenol A diglycidyl ether) are reactively extruded at 140-220°C to obtain a compatibilized PP / HDPE blend.

[0121] Comparative Example 6

[0122] 70 parts of homopolymer PP and 30 parts of HDPE, 3 parts of reaction reagent (maleic anhydride) and 0.5 parts of initiator (dicumyl peroxide) are melt-blended at 130-190°C and reactively extruded to obtain a grafted modified material; then the grafted modified material, 8 parts of a cross-linking agent (bisphenol A diglycidyl ether) and 1 part of a catalyst (stannous octoate) are reactively extruded at 140-220°C to obtain a compatibilized PP / HDPE blend.

[0123] Comparative Example 7

[0124] 70 parts of homopolymer PP and 30 parts of HDPE, 3 parts of reaction reagent (maleic anhydride), 0.5 parts of initiator (diisopropyl benzene peroxide) and 2 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-190°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material, 25 parts of a cross-linking agent (bisphenol A diglycidyl ether) and 1 part of a catalyst (stannous octoate) are reactively extruded at 140-220°C to obtain a compatibilized PP / HDPE blend.

[0125] Comparative Example 8

[0126] 50 parts of homopolymer PP and 50 parts of HDPE, 4 parts of reaction reagent (maleic anhydride), 0.6 parts of initiator (diisopropylbenzene peroxide) and 3 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-180°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material, 10 parts of a cross-linking agent (bisphenol F diglycidyl ether) and 1.5 parts of a catalyst (stannous octoate) are reactively extruded at 140-230°C to obtain a compatibilized PP / HDPE blend.

[0127] The products obtained in Examples 1 to 10 and Comparative Examples 1 to 8 in the polypropylene / polyethylene blend system were prepared into specimens using a hot press and subjected to mechanical property tests at room temperature (25° C.). The test data are shown in Table 1.

[0128] Table 1

[0129]

[0130]

[0131] Polypropylene (PP) / polyolefin elastomer (POE) blend system

[0132] Example 1

[0133] 85 parts of homopolymer PP and 15 parts of POE, 3 parts of reaction reagent (maleic anhydride), 0.5 parts of initiator (diisopropylbenzene peroxide) and 2 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-190°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material, 8 parts of cross-linking agent (bisphenol A diglycidyl ether) and 1 part of catalyst (stannous octoate) are reactively extruded at 140-220°C to obtain a compatibilized PP / POE blend.

[0134] Example 2

[0135] 70 parts of copolymerized PP and 30 parts of POE recycled materials, 4 parts of reaction reagent (itaconic anhydride), 0.6 parts of initiator (benzoyl peroxide) and 3 parts of auxiliary agent (styrene) are melt-blended at 130-170°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material, 10 parts of a cross-linking agent (polyethylene glycol diglycidyl ether) and 1.5 parts of a catalyst (zinc acetylacetonate) are reactively extruded at 150-240°C to obtain a compatibilized PP / POE blend.

[0136] Example 3

[0137] 90 parts of homopolymer PP and 10 parts of POE, 6 parts of reaction reagent (nadic anhydride), 1 part of initiator (azobisisobutyronitrile) and 5 parts of auxiliary agent (dimethylaniline) are melt-blended at 150-210°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material, 12 parts of a cross-linking agent (1,4-butanediol) and 2.5 parts of a catalyst (triphenylphosphine) are reactively extruded at 160-260°C to obtain a compatibilized PP / POE blend.

[0138] Comparative Example 1

[0139] 85 parts of homopolymer PP and 15 parts of POE were melt blended at 130-190°C to obtain a PP / POE blend.

[0140] Comparative Example 2

[0141] 85 parts of homopolymer PP and 15 parts of POE, 0.5 parts of initiator (diisopropylbenzene peroxide) and 2 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-190°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material, 8 parts of a cross-linking agent (bisphenol A diglycidyl ether) and 1 part of a catalyst (stannous octoate) are reactively extruded at 140-220°C to obtain a compatibilized PP / POE blend.

[0142] The products obtained in Examples 1 to 3 and Comparative Examples 1 and 2 in the polypropylene / polyolefin elastomer blend system were prepared into specimens using a hot press and subjected to mechanical property tests at room temperature (25° C.). The test data are shown in Table 2.

[0143] Table 2

[0144] Example Tensile strength (MPa) Elongation at break (%) Example 1 26.4±2.8 410±33 Example 2 21.6±1.5 560±41 Example 3 28.2±2.1 330±22 Comparative Example 1 16.3±1.8 150±11 Comparative Example 2 14.2±1.4 100±8

[0145] Ethylene-vinyl acetate copolymer (EVA) / polyethylene (PE) blend system

[0146] Example 1

[0147] 60 parts of EVA (VA content 18%), 40 parts of LDPE, 3 parts of a reaction reagent (maleic anhydride), 0.6 parts of an initiator (diisopropyl benzene peroxide) and 3 parts of an auxiliary agent (divinylbenzene) are melt-blended at 130-170°C, and a grafted modified material is obtained by reactive extrusion. Subsequently, the grafted modified material, 10 parts of a cross-linking agent (bisphenol A diglycidyl ether) and 1.2 parts of a catalyst (stannous octoate) are reactively extruded at 140-200°C to obtain a compatibilized EVA / LDPE blend.

[0148] Example 2

[0149] 50 parts (containing 30% EVA recycled material) of EVA (VA content 12%), 50 parts of HDPE, 5 parts of a reaction reagent (itaconic anhydride), 0.8 parts of an initiator (benzoyl peroxide) and 4 parts of an auxiliary agent (styrene) are melt-blended at 140-190° C., and a grafted modified material is obtained by reactive extrusion. Subsequently, the grafted modified material, 15 parts of a cross-linking agent (polyethylene glycol diglycidyl ether) and 2 parts of a catalyst (zinc acetylacetonate) are reactively extruded at 130-220° C. to obtain a compatibilized copolymerized EVA / HDPE blend.

[0150] Example 3

[0151] 70 parts of EVA (VA content 32%) and 30 parts of LLDPE, 6 parts of reaction reagent (nadic anhydride), 1 part of initiator (azobisisobutyronitrile) and 5 parts of auxiliary agent (dimethylaniline) are melt-blended at 150-210°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material, 12 parts of a cross-linking agent (1,4-butanediol) and 2.5 parts of a catalyst (triphenylphosphine) are reactively extruded at 130-240°C to obtain a compatibilized copolymerized EVA / LLDPE blend.

[0152] Comparative Example 1

[0153] 60 parts of EVA (VA content 18%) and 40 parts of LDPE were melt-blended at 130-170° C. to obtain an EVA / LDPE blend.

[0154] Comparative Example 2

[0155] 50 parts (containing 30% EVA recycled material) of EVA (VA content 12%), 50 parts of HDPE, 0.8 parts of initiator (benzoyl peroxide) and 4 parts of auxiliary agent (styrene) are melt-blended at 140-190°C, and a grafted modified material is obtained by reactive extrusion; then the grafted modified material, 15 parts of a cross-linking agent (polyethylene glycol diglycidyl ether) and 2 parts of a catalyst (zinc acetylacetonate) are reactively extruded at 130-220°C to obtain a compatibilized EVA / HDPE blend.

[0156] The products obtained in Examples 1 to 3 and Comparative Examples 1 and 2 in the ethylene-vinyl acetate copolymer (EVA) / polyethylene (PE) blend system were prepared into specimens using a hot press and mechanical properties were tested at room temperature (25°C). The test data are shown in Table 3.

[0157] Table 3

[0158]

[0159]

[0160] Ethylene vinyl alcohol copolymer (EVOH) / polyethylene (PE) blend system

[0161] Example 1

[0162] 20 parts of EVOH (32% vinyl alcohol content) and 80 parts of LDPE, 4 parts of reaction reagent (maleic anhydride), 0.8 parts of initiator (diisopropylbenzene peroxide) and 3 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-190°C, and a grafted modified material is obtained by reactive extrusion; then the grafted modified material, 12 parts of a cross-linking agent (bisphenol A diglycidyl ether) and 1.5 parts of a catalyst (stannous octoate) are reactively extruded at 130-210°C to obtain a compatibilized EVOH / LDPE blend.

[0163] Example 2

[0164] 40 parts (containing 25% EVOH recycled material) EVOH (vinyl alcohol content 44%) and 60 parts LLDPE, 6 parts of reaction reagent (itaconic anhydride), 1 part of initiator (benzoyl peroxide) and 5 parts of auxiliary agent (styrene) are melt-blended at 140-210°C, and a grafted modified material is obtained by reactive extrusion; then the grafted modified material, 15 parts of a cross-linking agent (polyethylene glycol diglycidyl ether) and 2 parts of a catalyst (zinc acetylacetonate) are reactively extruded at 160-240°C to obtain a compatibilized EVOH / LLDPE blend.

[0165] Example 3

[0166] 70 parts of EVOH (38% vinyl alcohol content) and 30 parts of HDPE, 5 parts of reaction reagent (nadic anhydride), 1.2 parts of initiator (azobisisobutyronitrile) and 4 parts of auxiliary agent (dimethylaniline) are melt-blended at 130-180°C and subjected to reactive extrusion to obtain a grafted modified material; then the grafted modified material, 10 parts of a cross-linking agent (1,4-butanediol) and 2 parts of a catalyst (triphenylphosphine) are reactively extruded at 150-230°C to obtain a compatibilized EVOH / HDPE blend.

[0167] Comparative Example 1

[0168] 20 parts of EVOH (vinyl alcohol content 32%) and 80 parts of LDPE were melt blended at 130-190° C. to obtain a compatibilized EVOH / LDPE blend.

[0169] Comparative Example 2

[0170] 40 parts (containing 25% EVOH recycled material) EVOH (vinyl alcohol content 44%) and 60 parts LLDPE, 1 part initiator (benzoyl peroxide) and 5 parts auxiliary agent (styrene) are melt-blended at 140-210°C, and a grafted modified material is obtained by reactive extrusion; then the grafted modified material, 15 parts of a cross-linking agent (polyethylene glycol diglycidyl ether) and 2 parts of a catalyst (zinc acetylacetonate) are reactively extruded at 160-240°C to obtain a compatibilized copolymerized EVOH / LLDPE blend.

[0171] The products obtained in Examples 1 to 3 and Comparative Examples 1 and 2 in the ethylene-vinyl alcohol copolymer (EVOH) / polyethylene (PE) blend system were prepared into specimens using a hot press and subjected to mechanical property testing at room temperature (25°C). The test data are shown in Table 4.

[0172] Table 4

[0173] Example Tensile strength (MPa) Elongation at break (%) Example 1 27.6±2.4 245±16 Example 2 33.1±2.5 192±14 Example 3 24.2±1.8 218±18 Comparative Example 1 16.5±1.2 76±6 Comparative Example 2 20.1±2.6 86±5

[0174] Polystyrene (PS) and / or polypropylene (PP) and / or polyethylene (PE) blending system

[0175] Example 1

[0176] 30 parts of HIPS and 70 parts of PP, 3 parts of a reaction reagent (maleic anhydride), 0.6 parts of an initiator (diisopropyl benzene peroxide) and 2 parts of an auxiliary agent (divinylbenzene) are melt-blended at 130-190°C and reacted and extruded to obtain a grafted modified material. The grafted modified material, 10 parts of a cross-linking agent (bisphenol A diglycidyl ether) and 1.2 parts of a catalyst (stannous octoate) are then reacted and extruded at 140-220°C to obtain a compatibilized HIPS / PP blend.

[0177] Example 2

[0178] 60 parts of GPPS and 40 parts of PP, 5 parts of reaction reagent (itaconic anhydride), 0.8 parts of initiator (benzoyl peroxide) and 4 parts of auxiliary agent (styrene) are melt-blended at 150-220°C and reactively extruded to obtain a grafted modified material; then the grafted modified material, 15 parts of a cross-linking agent (polyethylene glycol diglycidyl ether) and 2 parts of a catalyst (zinc acetylacetonate) are reactively extruded at 160-240°C to obtain a compatibilized GPPS / PP blend.

[0179] Example 3

[0180] 40 parts of HIPS and 60 parts of PP (containing 30% recycled PP), 4 parts of reaction reagent (maleic anhydride), 0.7 parts of initiator (diisopropylbenzene peroxide) and 3 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-180°C and reactively extruded to obtain a grafted modified material; then the grafted modified material, 12 parts of a cross-linking agent (bisphenol A diglycidyl ether) and 1.5 parts of a catalyst (1,5,7-triazabicyclo[4.4.0]dec-5-ene) are reactively extruded at 150-230°C to obtain a compatibilized HIPS / PP blend.

[0181] Example 4

[0182] 25 parts of HIPS and 75 parts of LLDPE, 3 parts of a reaction reagent (maleic anhydride), 0.5 parts of an initiator (dicumyl peroxide) and 2 parts of an auxiliary agent (divinylbenzene) are melt-blended at 140-200°C and reactively extruded to obtain a grafted modified material. The grafted modified material, 8 parts of a crosslinking agent (bisphenol A diglycidyl ether) and 1 part of a catalyst (stannous octoate) are then reactively extruded at 140-220°C to obtain a compatibilized HIPS / LLDPE blend.

[0183] Example 5

[0184] 50 parts of GPPS and 50 parts of HDPE, 6 parts of reaction reagent (itaconic anhydride), 1 part of initiator (benzoyl peroxide) and 5 parts of auxiliary agent (styrene) are melt-blended at 130-195°C and reactively extruded to obtain a grafted modified material; then the grafted modified material, 18 parts of a cross-linking agent (epoxidized soybean oil) and 2.5 parts of a catalyst (zinc acetate) are reactively extruded at 170-250°C to obtain a compatibilized GPPS / HDPE blend.

[0185] Example 6

[0186] 35 parts of HIPS and 65 parts of LDPE (containing 25% LDPE recycled material), 4 parts of reaction reagent (maleic anhydride), 0.6 parts of initiator (diisopropylbenzene peroxide) and 3 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-185°C, and a grafted modified material is obtained by reactive extrusion; then the grafted modified material, 10 parts of cross-linking agent (1,4-butanediol) and 2 parts of catalyst (triphenylphosphine) are reactively extruded at 150-225°C to obtain a compatibilized HIPS / LDPE blend.

[0187] Example 7

[0188] 40 parts of HIPS, 30 parts of PP, 30 parts of LLDPE, 5 parts of a reaction reagent (nadic anhydride), 1.2 parts of an initiator (azobisisobutyronitrile) and 4 parts of an auxiliary agent (dimethylaniline) were melt-blended at 140-210°C and subjected to reactive extrusion to obtain a grafted modified material. Subsequently, the grafted modified material, 15 parts of a cross-linking agent (bisphenol A diglycidyl ether) and 2 parts of a catalyst (1 part of stannous octoate and 1 part of triphenylphosphine) were reactively extruded at 160-240°C to obtain a compatibilized HIPS / PP / LLDPE blend.

[0189] Example 8

[0190] 20 parts of GPPS and 80 parts of LLDPE, 2 parts of a reaction reagent (maleic anhydride), 0.4 parts of an initiator (dicumyl peroxide) and 1.5 parts of an auxiliary agent (divinylbenzene) were melt-blended at 160-230°C and subjected to reactive extrusion to obtain a grafted modified material; the grafted modified material, 20 parts of a crosslinker (epoxidized soybean oil) and 3 parts of a catalyst (1,5,7-triazabicyclo[4.4.0]dec-5-ene) were then reactively extruded at 140-210°C to obtain a compatibilized GPPS / LLDPE blend.

[0191] Comparative Example 1

[0192] 30 parts of GPPS and 70 parts of PP were melt blended at 130-190°C to obtain a GPPS / PP blend.

[0193] Comparative Example 2

[0194] 30 parts of HIPS and 70 parts of PP, 0.6 parts of initiator (diisopropylbenzene peroxide) and 2 parts of auxiliary agent (divinylbenzene) are melt-blended at 130-190°C and reactively extruded to obtain a grafted modified material; then the grafted modified material, 10 parts of a cross-linking agent (bisphenol A diglycidyl ether) and 1.2 parts of a catalyst (stannous octoate) are reactively extruded at 140-220°C to obtain a compatibilized HIPS / PP blend.

[0195] Comparative Example 3

[0196] 25 parts of HIPS and 75 parts of LLDPE, 3 parts of a reaction reagent (maleic anhydride) and 2 parts of an auxiliary agent (divinylbenzene) are melt-blended at 140-200°C and subjected to reactive extrusion to obtain a grafted modified material. Subsequently, the grafted modified material, 8 parts of a cross-linking agent (bisphenol A diglycidyl ether) and 1 part of a catalyst (stannous octoate) are reactively extruded at 140-220°C to obtain a compatibilized HIPS / LLDPE blend.

[0197] Comparative Example 4

[0198] 60 parts of GPPS and 40 parts of PP, 5 parts of reaction reagent (itaconic anhydride), 0.8 parts of initiator (benzoyl peroxide) and 4 parts of auxiliary agent (styrene) are melt-blended at 110-125°C and reactively extruded to obtain a grafted modified material; then the grafted modified material, 15 parts of a cross-linking agent (polyethylene glycol diglycidyl ether) and 2 parts of a catalyst (zinc acetylacetonate) are reactively extruded at 160-240°C to obtain a compatibilized GPPS / PP blend.

[0199] The products obtained in Examples 1 to 8 and Comparative Examples 1 to 4 in the polystyrene (PS) and / or polypropylene (PP) and / or polyethylene (PE) blend system were prepared into specimens using a hot press and mechanical properties were tested at room temperature (25°C). The test data are shown in Table 5.

[0200] Table 5

[0201]

[0202]

[0203] As shown in Tables 1 to 5, the thermoplastic compatibilized blends prepared in accordance with the present invention exhibit improved mechanical properties, particularly significant increases in elongation at break. This further demonstrates the significant enhancement of compatibility between incompatible or partially compatible thermoplastic polymers, demonstrating excellent in-situ compatibilization. Furthermore, the compatibilized blends prepared in accordance with the present invention are reproducible and can be prepared using recycled thermoplastic polymers, thus offering high-value-added applications.

[0204] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may be modified or some of the technical features thereof may be replaced with equivalents. Such modifications or replacements do not deviate from the essence of the corresponding technical solutions and the spirit and scope of the technical solutions of the various embodiments of the present invention. Any portions of the present invention not described in detail are well known to those skilled in the art.

Claims

1. A method for preparing a thermoplastic blend with dynamic covalent bond compatibilization, characterized in that: include: (1) melt blending at least two incompatible or partially compatible thermoplastic polymer blends, a reaction reagent containing anhydride or carboxyl groups, an initiator, and an auxiliary agent in a mass ratio of 100:(0.5-12):(0.05-1.5):(0.5-12), and obtaining a grafted modified material by reactive extrusion; (2) melt-blending the grafted modified material with a cross-linking agent containing epoxy or hydroxyl groups and a catalyst in a mass ratio of 100:(1-20):(0.1-5), forming a dynamic covalent bond network through reactive extrusion, and obtaining a compatibilized blend.

2. The method according to claim 1, characterized in that The thermoplastic polymer blend is one of the following blending systems: a: A blend of polypropylene and polyethylene, wherein: The mass ratio of the polypropylene to the polypropylene is 5:95 to 95:5; b: Blends of polypropylene and polyolefin elastomers, wherein: The content of the polyolefin elastomer in the blend is 5-40wt%; c: Polar / non-polar blend, where: The polar / non-polar blend is a blend of ethylene-vinyl acetate copolymer and polyethylene in a mass ratio of 10:90 to 90:10 or a blend of ethylene-vinyl alcohol copolymer and polyethylene in a mass ratio of 5:95 to 95:5; d: Blends of polystyrene with polypropylene and / or polyethylene, wherein: The mass ratio of the polystyrene to the polypropylene and / or the polyethylene is 5:95 to 95:5; Wherein, the polypropylene is homopolymer polypropylene or copolymer polypropylene; The polyethylene is high-density polyethylene, low-density polyethylene or linear low-density polyethylene; The polystyrene is general-purpose polystyrene or high-impact polystyrene; Preferably, the blend contains no more than 50 wt% of recycled or regenerated materials of the corresponding thermoplastic polymer and no more than 5 wt% of impurities.

3. The method according to claim 1, characterized in that The reaction reagent in step (1) is C4-C 20 The aliphatic or aromatic dianhydride and dicarboxylic acid are preferably one or more of maleic anhydride, itaconic anhydride, nadic anhydride or itaconic acid.

4. The method according to claim 1, wherein The initiator in step (1) is an organic peroxide or an azo compound, preferably one or more of azobisisobutyronitrile, dicumyl peroxide, benzoyl peroxide or tert-butyl hydroperoxide.

5. The method according to claim 1, wherein The auxiliary agent in step (1) is a free radical stabilizer or a reaction accelerator, preferably one or more of divinylbenzene, styrene or dimethylaniline.

6. The method according to claim 1, characterized in that The cross-linking agent in step (2) is a compound that can undergo epoxy ring-opening esterification or alcohol ester exchange reaction with anhydride / carboxyl group, preferably one or more of bisphenol A diglycidyl ether, polyethylene glycol diglycidyl ether, bisphenol F diglycidyl ether, 1,4-butanediol diglycidyl ether, trimethylolpropane, 1,4-butanediol, epoxidized soybean oil or epoxidized castor oil.

7. The method according to claim 1, characterized in that The catalyst in step (2) is a compound capable of promoting epoxy-anhydride ring-opening reaction and / or transesterification reaction, preferably one or more of stannous octoate, zinc acetate, zinc acetylacetonate, 1,5,7-triazabicyclo[4.4.0]dec-5-ene or triphenylphosphine.

8. The method according to any one of claims 1 to 7, characterized in that The reaction extrusion process window of step (1) is: screw speed 40-300 rpm; melt temperature 130-280°C; The reaction extrusion process window of step (2) is: screw speed 60-450rpm; melt temperature 130-300℃.

9. A dynamically covalently compatibilized thermoplastic blend prepared according to the method of any one of claims 1 to 8, characterized in that: The elongation at break of the dynamic covalent bond compatibilized thermoplastic blend is ≥80%.

10. Use of the dynamically covalently compatibilized thermoplastic blend according to claim 9, characterized in that: Used to manufacture packaging films, automotive interior parts, electronic and electrical appliance casings or high-value products made from recycled plastics.

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