阅读说明：本技术 一种高强高韧阻燃再生塑料及其制备方法 (High-strength high-toughness flame-retardant regenerated plastic and preparation method thereof ) 是由 沈佳斌 何露 郭少云 于 2020-06-28 设计创作，主要内容包括：本发明公开了一种高强高韧阻燃再生塑料及其制备方法,包括由废旧塑料与橡胶熔融共混造粒制得的增韧层树脂原料,和由无机粒子与阻燃剂复配的功能添加剂与废旧塑料熔融共混造粒制得的增强层树脂原料,经共挤出制备得到增韧层与增强层交替排布的多层状再生塑料,所述增强层具有高强度和阻燃性,所述增韧层具有韧性和抗冲击性,所述多层状再生塑料的层数和层厚比可调可控。本发明将组分配方设计与层状仿生结构设计相结合,最大限度发挥各组分性能优势,实现废旧塑料的高性能化再生利用。(The invention discloses a high-strength high-toughness flame-retardant regenerated plastic and a preparation method thereof, wherein the high-strength high-toughness flame-retardant regenerated plastic comprises a toughening layer resin raw material prepared by melting, blending and granulating waste plastics and rubber, and an enhancement layer resin raw material prepared by melting, blending and granulating functional additives compounded by inorganic particles and flame retardants and the waste plastics, and is prepared by co-extrusion to obtain a multilayer regenerated plastic with alternately arranged toughening layers and enhancement layers, wherein the enhancement layers have high strength and flame retardance, the toughening layers have toughness and impact resistance, and the number of layers and the thickness ratio of the multilayer regenerated plastic are adjustable and controllable. The invention combines the component formula design with the layered bionic structure design, gives full play to the performance advantages of each component to the maximum extent, and realizes the high-performance recycling of the waste plastics.)

1. The preparation method of the high-strength high-toughness flame-retardant regenerated plastic is characterized by comprising the following steps of:

A. melting and blending waste plastics and rubber, granulating to obtain a toughening layer resin raw material, fully mixing inorganic particles and a flame retardant in an air flow mixing system, and then melting, blending and granulating with the waste plastics to obtain an enhancement layer resin raw material;

B. respectively putting the reinforcing layer resin raw material and the toughening layer resin raw material into an extruder for melt co-extrusion;

C. and filtering the melt in the two groups of extruders to remove large-particle-size particles, allowing the melt to flow into a junction station to form a laminated structure of the enhancement layer and the toughening layer, allowing the laminated structure to enter a layer multiplier to be cut and laminated, and performing traction and cooling to prepare the multilayer regenerated plastic with the toughening layer and the enhancement layer alternately arranged.

2. The method for preparing the high-strength high-toughness flame-retardant recycled plastic as claimed in claim 1, wherein the waste plastic refers to a plastic raw material obtained by recycling, cleaning and crushing after one-time thermoplastic forming, and the mass fraction of the solid content in the waste plastic is less than 25%, and the solid content refers to metal, inorganic matter or high-melting-point organic matter which cannot be melted in the thermoplastic processing of the waste plastic.

3. The preparation method of the high-strength high-toughness flame-retardant regenerated plastic as claimed in claim 1, wherein the toughening layer resin raw material is obtained by melt blending rubber and waste plastic in a mass ratio of 1:1-10 and granulating, the reinforcing layer resin raw material is a functional additive and the waste plastic in a mass ratio of 1: 1-5, and granulating to obtain the compound particle for synchronously improving the strength and the flame retardance of the material, wherein the functional additive is the compound particle obtained by fully mixing inorganic particles and a flame retardant in a gas flow mixing system according to the mass ratio of 2:1-1: 4.

4. The method for preparing the high-strength high-toughness flame-retardant recycled plastic according to claim 1, wherein a filtering device is arranged between the extruder and the junction station, a filter screen is arranged in the filtering device to filter out large-particle-size particles in the melt to promote particle dispersion, and the maximum mesh number of the filter screen is 400 meshes.

5. The method for preparing high-strength high-toughness flame-retardant recycled plastic according to claim 3, wherein the inorganic particles can be one or more of talcum powder, SiO2, glass fiber, CaCO3 or montmorillonite.

6. The preparation method of the high-strength high-toughness flame-retardant recycled plastic as claimed in claim 1, wherein 1% -3% of a coupling agent is added into the toughening layer, and the coupling agent comprises one or more of a titanate coupling agent, an aluminate coupling agent or a silane coupling agent.

7. The method for preparing high-strength high-toughness flame-retardant recycled plastic according to claim 1, wherein 1% -3% of a compatibilizer is arranged in the toughening layer, the compatibilizer layer comprises a reactive compatibilizer and a non-reactive compatibilizer, the reactive compatibilizer comprises one or more of a carboxylic acid compatibilizer, an anhydride compatibilizer or an epoxy compatibilizer, and the non-reactive compatibilizer comprises one or more of a block copolymer compatibilizer, a graft copolymer compatibilizer or a random copolymer compatibilizer.

8. The method for preparing high-strength high-toughness flame-retardant recycled plastic according to claim 1, wherein the number of the layer multipliers is n (1, 2, 3, …), and the corresponding number of the composite material layers is 2⁽ⁿ⁺¹⁾And the maximum value of n can be selected to be 10.

9. The high-strength high-toughness flame-retardant regenerated plastic comprises a waste plastic matrix, and is characterized in that: the high-strength high-toughness flame-retardant regenerated plastic comprises a reinforcing layer and a toughening layer arranged on the surface of the reinforcing layer, wherein the reinforcing layer is uniformly dispersed in a waste plastic matrix through flame retardants and inorganic reinforcing particles, the toughening layer is uniformly dispersed in the waste plastic matrix through rubber particles, the reinforcing layer has high strength and flame retardance, the toughening layer has toughness and impact resistance, and the high-strength high-toughness flame-retardant regenerated plastic is of an overlapped structure with at least two or more layers, so that the odd-numbered layer and the even-numbered layer of the high-strength high-toughness flame-retardant regenerated plastic have different performances.

Technical Field

The invention relates to the technical field of plastic recycling, in particular to a high-strength, high-toughness and flame-retardant plastic and a preparation method thereof.

Background

With the wide application of polymer materials in various industries, a large amount of waste plastics are generated, which causes great environmental problems, and thus the requirement of recycling is urgent. For most waste plastics, due to the existence of the filler additive and the degradation of molecular chains in the secondary processing process, the comprehensive performance of the waste plastics is difficult to meet the requirements of consumers on the aspects of product aesthetics, functionality, safety and the like, so that the waste plastics are rarely directly utilized and most of the waste plastics need to be modified necessarily. Alloying with other polymers or compounding with fillers is a main way for recycling waste plastics at present, but the balance of various properties is difficult to be considered. For example, the rigidity and heat resistance of waste polypropylene (PP) can be improved by dispersing inorganic particles in the PP, but the movement of molecular chains is limited, which leads to the decrease of toughness; dispersing the rubber in the waste PP will significantly increase the impact strength and elongation at break of the latter, however the stiffness and heat resistance will be reduced therewith. Therefore, how to fully exert the performance advantages of each component is important to realize the efficient and high-performance modification of the waste plastics.

201810264293.2 discloses a method for preparing high-strength high-toughness polypropylene regenerated particles. The method coats the activated rigid particles through the elastomer to form core-shell structure particles to reinforce and toughen the waste polypropylene material. The process is complicated, the modification cost is high, and the construction of the core-shell structure is uncertain and can be damaged in the melt processing.

Li et al [ Polymer, 2017, 124: 41-47 discloses a reactive melt blending modification method, which enables waste ABS (rABS) and phthalic anhydride (PMDA) to carry out in-situ chain extension reaction, and realizes synchronous promotion of the strength and toughness of the rABS. When 0.9 wt% PMDA was added, the notched impact strength and tensile strength of the PMDA/rABS were improved by 140% and 36% over that of rABS. Although the technical modification effect is obvious, the controllability of chain extension reaction in the thermoplastic processing process is low, and the batch stability of the product performance is difficult to control.

At present, the high-performance modification of most of waste plastics is realized by melt blending of various functional modification components. However, the phase morphology of the blend is often limited by the viscosity ratio, component ratio, compatibility and the like of each component, so that multiple factors need to be considered and balanced to prepare the high-strength high-toughness flame-retardant recycled plastic through blending, so that many limitations are brought to the design, processing and the like of materials, and the final properties are often lost, so that the application requirements are difficult to meet.

Disclosure of Invention

The invention aims to provide a preparation method for synchronously improving the strength, toughness and flame retardant property of waste plastics to solve the existing problems.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention comprises the following steps:

A. melting and blending waste plastics and rubber, granulating to obtain a toughening layer resin raw material, fully mixing inorganic particles and a flame retardant in an air flow mixing system, and then melting, blending and granulating with the waste plastics to obtain an enhancement layer resin raw material;

B. respectively putting the reinforcing layer resin raw material and the toughening layer resin raw material into an extruder for melt co-extrusion;

C. and filtering the melt in the two groups of extruders to remove large-particle-size particles, allowing the melt to flow into a junction station to form a laminated structure of the enhancement layer and the toughening layer, allowing the laminated structure to enter a layer multiplier to be cut and laminated, and performing traction and cooling to prepare the multilayer regenerated plastic with the toughening layer and the enhancement layer alternately arranged.

Furthermore, the waste plastic refers to a plastic raw material obtained by recycling, cleaning and crushing after one-time thermoplastic forming processing, the mass fraction of the solid content in the waste plastic is less than 25%, and the solid content refers to metal, inorganic matters or high-melting-point organic matters which can not be melted in the thermoplastic processing of the waste plastic.

Further, the raw material of the resin of the toughening layer is prepared by melting, blending and granulating rubber and waste plastic according to a mass ratio of 1:1-10, and the raw material of the resin of the reinforcing layer is prepared by mixing a functional additive and the waste plastic according to a mass ratio of 1: 1-5, and granulating to obtain the composite particles for synchronously improving the strength and the flame retardance of the material, wherein the functional additive is the compound particles obtained by fully mixing inorganic particles and the flame retardant in an air flow mixing system according to the mass ratio of 2:1-1:4, and the air flow mixing system is a mixing device which uses compressed air as stirring power and is only used for dispersing and mixing the inorganic particles and the flame retardant without influencing the morphological structure and the particle size of the inorganic particles and the flame retardant.

Furthermore, each extruder is connected with the junction station through a filtering device, the filtering device filters large-particle-size particles in the melt through selecting and installing a certain mesh number of filtering screens, and the effect of further promoting the dispersion of the particles is achieved, and the maximum mesh number of the filtering screens is 400 meshes.

Further, the inorganic particles may be one or more of talc, SiO2, glass fiber, CaCO3, or montmorillonite.

Further, 1% -3% of a coupling agent is added into the toughening layer, and the coupling agent comprises one or more of a titanate coupling agent, an aluminate coupling agent or a silane coupling agent.

Further, 1% -3% of a compatibilizer is arranged in the toughening layer, the compatibilizer layer comprises a reactive compatibilizer and a non-reactive compatibilizer, the reactive compatibilizer comprises one or more of a carboxylic acid compatibilizer, an anhydride compatibilizer or an epoxy compatibilizer, and the non-reactive compatibilizer comprises one or more of a block copolymer compatibilizer, a graft copolymer compatibilizer or a random copolymer compatibilizer.

Further, the number of layer multipliers is n (1, 2, 3, …), corresponding to a composite layer number of 2⁽ⁿ⁺¹⁾And the maximum value of n can be selected to be 10.

The high-strength high-toughness flame-retardant regenerated plastic comprises a waste plastic substrate, an enhancement layer and a toughening layer arranged on the surface of the enhancement layer, wherein the enhancement layer is uniformly dispersed in the waste plastic substrate through flame retardants and inorganic reinforcing particles, the toughening layer is uniformly dispersed in the waste plastic substrate through rubber particles, the enhancement layer has high strength and flame retardance, the toughening layer has toughness and impact resistance, and the high-strength high-toughness flame-retardant regenerated plastic is of an overlapped structure with at least two or more layers, so that the odd layers and the even layers of the high-strength high-toughness flame-retardant regenerated plastic have different performances.

Compared with the prior art, the invention has the beneficial effects that:

1. the component formula design and the layered bionic structure design are combined, the performance advantages of each component are exerted to the maximum extent, and the high-performance reutilization of the waste plastic is realized.

2. The components of different formulas are alternately arranged in multiple layers, so that the purposes of efficient utilization, redundancy reduction and synergistic interaction are achieved, and the strength, toughness and flame retardance of the waste plastic are synchronously improved under the condition of low particle filling.

Drawings

FIG. 1 is a schematic view of a production process of the present invention;

FIG. 2 is an enlarged view of the structure of the plastic of the present invention;

in the figure: 1-reinforcing layer, 2-rubber, 3-toughening layer, 4-inorganic particle 5-flame retardant (IFR).

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments.

As shown in fig. 1 and 2, the present invention comprises the steps of:

the invention comprises the following steps:

A. melting and blending waste plastics and rubber, granulating to obtain a toughening layer resin raw material, fully mixing inorganic particles and a flame retardant in an air flow mixing system, and then melting, blending and granulating with the waste plastics to obtain an enhancement layer resin raw material;

B. respectively putting the reinforcing layer resin raw material and the toughening layer resin raw material into an extruder for melt co-extrusion;

C. and filtering out large-particle-size particles from the melts in the two groups of extruders, allowing the filtered large-particle-size particles to flow into a junction station to form a laminated structure of the reinforcing layer and the toughening layer, allowing the laminated structure to enter a layer multiplier for cutting and laminating, and performing traction and cooling to prepare the multilayer regenerated plastic with the toughening layer and the reinforcing layer alternately arranged.

The waste plastic is a plastic raw material obtained by recycling, cleaning and crushing after one-time thermoplastic forming processing, the mass fraction of the solid content in the waste plastic is less than 25%, and the solid content refers to metal, inorganic matters or high-melting-point organic matters which can not be melted in the thermoplastic processing of the waste plastic.

The toughening layer resin raw material is prepared by melting, blending and granulating rubber and waste plastic according to a mass ratio of 1:1-10, and is used for improving the toughness of the material, and the reinforcing layer resin raw material is prepared by mixing a functional additive and the waste plastic according to a mass ratio of 1: 1-5, and granulating to obtain the composite particles for synchronously improving the strength and the flame retardance of the material, wherein the functional additive is the compound particles obtained by fully mixing inorganic particles and the flame retardant in an air flow mixing system according to the mass ratio of 2:1-1:4, and the air flow mixing system is a mixing device which uses compressed air as stirring power and is only used for dispersing and mixing the inorganic particles and the flame retardant without influencing the morphological structure and the particle size of the inorganic particles and the flame retardant.

Each extruder is connected with the junction station through a filter device, the filter device filters large-particle-size particles in the melt through selecting and installing a filter screen with a certain mesh number, and the effect of further promoting the dispersion of the particles is achieved, and the maximum mesh number of the filter screen is 400 meshes.

The inorganic particles can be one or more of talcum powder, SiO2, glass fiber, CaCO3 or montmorillonite.

1% -3% of coupling agent is added into the toughening layer, and the coupling agent comprises one or more of titanate coupling agent, aluminate coupling agent or silane coupling agent.

The toughening layer is internally provided with 1-3% of a compatibilizer, the compatibilizer layer comprises a reactive compatibilizer and a non-reactive compatibilizer, the reactive compatibilizer comprises one or more of a carboxylic acid compatibilizer, an anhydride compatibilizer or an epoxy compatibilizer, and the non-reactive compatibilizer comprises one or more of a block copolymer compatibilizer, a graft copolymer compatibilizer or a random copolymer compatibilizer.

The number of layer multipliers is n (1, 2, 3, …), and the corresponding number of composite layers is 2⁽ⁿ⁺¹⁾And the maximum value of n can be selected to be 10.

The toughening layer is internally provided with 1-3% of a compatibilizer, the compatibilizer layer comprises a reactive compatibilizer and a non-reactive compatibilizer, the reactive compatibilizer comprises one or more of a carboxylic acid compatibilizer, an anhydride compatibilizer or an epoxy compatibilizer, and the non-reactive compatibilizer comprises one or more of a block copolymer compatibilizer, a graft copolymer compatibilizer or a random copolymer compatibilizer.

The waste plastic can be added with an antioxidant, a stabilizer and a lubricant, the number of the layer multipliers is n (1, 2, 3, …), and the number of the corresponding layers of the composite material is 2⁽ⁿ⁺¹⁾The maximum value of n can be selected to 10, and the waste plastic can be one or more of polypropylene, polyethylene, ABS, PVC or PMMA.

The waste plastic is used as a matrix, and the prepared reinforcing component/toughening component alternating multilayer composite material realizes the controllable distribution of the elastomer, the inorganic particles and the flame retardant. Due to the strong tensile shear brought by the layer multiplier and the limited layer space, the inorganic particles and the flame retardant can be more uniformly dispersed in the reinforcing component layer, and sufficient mechanical support can be provided; the toughening component layer filled with the rubber can directly absorb energy on one hand, and on the other hand, the expansion of silver cracks in the adjacent reinforcing component layer can be inhibited through a layer interface, so that the whole composite system has excellent toughness. In addition, the flame retardant network formed by compounding the flame retardant and the inorganic particles can realize good flame retardance on the reinforced component layer, and can also realize flame retardance protection on the adjacent toughened component layer by utilizing the inhibiting effect of the limited layer space on flame diffusion. Therefore, the design of the invention can effectively improve the strength, toughness and fire resistance of the waste plastic under the condition of low particle filling, and realize high-performance recycling of the waste plastic. The method has the advantages of simple process, high production efficiency and wide market prospect.

The high-strength high-toughness flame-retardant regenerated plastic comprises a waste plastic substrate, an enhancement layer and a toughening layer arranged on the surface of the enhancement layer, wherein the enhancement layer is uniformly dispersed in the waste plastic substrate through flame retardants and inorganic reinforcing particles, the toughening layer is uniformly dispersed in the waste plastic substrate through rubber particles, the enhancement layer has high strength and flame retardance, the toughening layer has toughness and impact resistance, and the high-strength high-toughness flame-retardant regenerated plastic is of an overlapped structure with at least two or more layers, so that the odd layers and the even layers of the high-strength high-toughness flame-retardant regenerated plastic have different performances.