CN111961309A

CN111961309A - Modified ABS reclaimed material and preparation method thereof

Info

Publication number: CN111961309A
Application number: CN202010670514.3A
Authority: CN
Inventors: 韩锐; 黄敬鉥; 李光照; 陈刚; 何太碧; 聂林; 王中最
Original assignee: Sichuan Xihua Technology Zone Management Co ltd; Xihua University
Current assignee: Sichuan Xihua Technology Zone Management Co ltd; Xihua University
Priority date: 2020-07-13
Filing date: 2020-07-13
Publication date: 2020-11-20

Abstract

The invention discloses a modified acrylonitrile-butadiene-styrene (ABS) reclaimed material and a preparation method thereof, wherein the modified ABS reclaimed material is prepared by modifying and regenerating waste ABS, and comprises the following raw materials in parts by weight: 100 parts of ABS reclaimed materials, 0.5-2 parts of initiator, 0.5-2 parts of chain extender A, 0.1-1 part of chain extender B and 5-10 parts of toughening agent. The preparation method comprises the following steps: uniformly mixing the crushed and dried ABS reclaimed materials with an initiator and a chain extender A, then carrying out first-step reactive melt blending to enable ABS molecular chains to carry out self-chain extension by virtue of active small molecules to obtain primary modified ABS reclaimed materials, then uniformly mixing the primary modified ABS reclaimed materials with a chain extender B and a toughening agent, then carrying out second-step reactive melt blending to extrude, granulate and dry, further expanding the ABS molecular chains and strengthening molecular chain entanglement networks, and finally obtaining the modified ABS reclaimed materials. The invention greatly improves the strength and toughness of the waste ABS plastic and the use value related to the waste ABS plastic, is easy to realize industrial production, and can effectively promote the recycling of the ABS.

Description

Modified ABS reclaimed material and preparation method thereof

Technical Field

The invention relates to the technical field of waste ABS regeneration, in particular to a modified ABS regenerated material and a preparation method thereof.

Background

In recent years, with the improvement of the living standard of a house, the variety and the number of household appliances are increased year by year, the updating speed of the waste household appliances is accelerated, a large amount of waste electronic appliances are abandoned, and a large amount of waste acrylonitrile-butadiene-styrene (ABS) shells to be treated are generated. However, after long-term use of ABS plastics, due to the fact that the unsaturated double bond structure in the polybutadiene rubber phase is affected by environmental factors such as oxygen, temperature, illumination and the like in the using process, aging degradation occurs, so that molecular chains are broken, the molecular weight is reduced sharply, the rubber phase is consumed, oxygen-containing groups such as hydroxyl (-OH), carboxyl (-COOH), ketone, aldehyde and the like are generated, then, styrene-acrylonitrile copolymer (SAN phase) is further initiated to degrade, and finally, the mechanical property of waste ABS is degraded. Therefore, in order to realize the high added value recycling of the waste ABS, it is critical to improve the mechanical properties of the waste ABS after secondary processing. Currently, the mechanical property of waste ABS is generally improved by simply melt blending of multi-component fillers, and the research on a reactive extrusion modification method based on selective double bond opening chain extension and molecular chain entanglement network reinforcement is less.

In the prior art, CN108102282A discloses a regenerated ABS material with synchronous chain extension, toughening and interface repair and a preparation method thereof, wherein a macromolecule chain extender acrylonitrile-butadiene-styrene copolymer grafted oxazoline (ABS-g-OZ) is used in combination with a chain extension accelerator without double bonds to synchronously chain-extend, toughen and repair the interface of the waste ABS. However, the invention does not fully utilize the active functional groups existing in the waste ABS and realizes the extension of molecular chains and the change of a topological structure of an entangled network by means of molecular chains; meanwhile, in order to continuously utilize the polybutadiene elastic phase in the ABS, residual double bonds in the waste ABS are not utilized, chain extension is realized through addition reaction, and the modified ABS reclaimed material is easy to degrade under continuous sunlight irradiation.

In the prior art, CN104045964A discloses a chemical toughening method for waste ABS plastics, which comprises preparing a thermoplastic polyurethane/maleic anhydride reactant, then melt blending and grafting with waste ABS, and melt grafting the double bonds of maleic anhydride and the double bonds of waste ABS or alpha-H on carbon adjacent to the double bonds under the action of dicumyl peroxide (DCP) as an initiator to achieve the purpose of modification while extruding and granulating. However, the free radical initiator DCP adopted by the invention has extremely high reaction activity, and the generated free radical has uncontrollable property, so that the main chain of the polymer molecular chain is easy to break, and the chain extension of the molecular chain is influenced negatively; in addition, the invention does not utilize active hydroxyl and carboxyl generated by aging of the waste ABS, so that the chain extension efficiency is improved, and the attempt to strengthen the molecular chain entanglement network in the waste ABS is avoided.

Disclosure of Invention

Aiming at the problems, the invention aims to provide a modified ABS reclaimed material and a preparation method thereof, which are characterized in that waste ABS is modified by fully utilizing active functional groups existing in the waste ABS and a proper amount of additional toughening agent, and finally, the high-added-value ABS reclaimed material with good strength and toughness is obtained.

The technical scheme of the invention is as follows:

on the one hand, the modified ABS reclaimed material comprises the following raw materials in parts by weight: 100 parts of ABS reclaimed materials, 0.5-2 parts of initiator, 0.5-2 parts of chain extender A, 0.1-1 part of chain extender B and 5-10 parts of toughening agent.

Preferably, the initiator is an initiator capable of selectively initiating homolytic cleavage of unsaturated carbon-carbon double bonds and free radical addition reaction.

Preferably, the initiator is azobisisobutyronitrile or azobisisoheptonitrile.

Preferably, the chain extender A is a small molecular compound containing a terminal hydroxyl group and/or a carboxyl group and having an unsaturated carbon-carbon double bond; the chain extender B is a small molecular compound containing three or four hydroxyl groups and at least two primary hydroxyl groups.

Preferably, the chain extender A is one or more of ricinoleic acid, itaconic acid and undecylenic acid; the chain extender B is one or more of trihydroxy methyl propane, glycerol and erythritol.

Preferably, the toughening agent is a rubber elastomer.

Preferably, the toughening agent is one or more of nitrile rubber, ethylene propylene diene monomer and styrene butadiene rubber.

On the other hand, the preparation method of the modified ABS reclaimed material comprises the following steps: crushing and drying the ABS reclaimed material for later use; carrying out reactive melt blending extrusion granulation on the crushed and dried ABS reclaimed material, an initiator, a chain extender A, a chain extender B and a toughening agent; and drying the product obtained by blending, extruding and granulating to obtain the modified ABS reclaimed material.

Preferably, a double-screw extruder is adopted for reactive melt blending extrusion granulation, and the extrusion granulation is carried out in two times, specifically: uniformly mixing the crushed and dried ABS reclaimed materials with an initiator and a chain extender A, then carrying out first extrusion granulation and drying to obtain a process product, and then continuously uniformly mixing the process product with a chain extender B and a toughening agent, and then carrying out second extrusion granulation.

Preferably, the specific steps of crushing and drying the ABS reclaimed material are as follows: and (3) putting the ABS reclaimed material into a grinder to be ground into particles with the particle size of less than 5mm, and then drying the ground ABS reclaimed material for 5-8 hours at the temperature of 60-80 ℃.

Preferably, during the first extrusion granulation, the temperature of a feeding section of the double-screw extruder is 80-100 ℃, the temperature of the highest temperature section in an extrusion, melting and mixing section is 170-180 ℃, the temperature of a neck mold is 190 ℃, and the rotating speed of a main machine is 40-60 r/min; the vacuum degree in the double-screw extruder is between 0.06 and 0.08 MPa.

Preferably, during the second extrusion granulation, the temperature of the feeding section of the double-screw extruder is 80-120 ℃, the temperature of the highest temperature section in the extrusion, melting and mixing section is 190-210 ℃, the temperature of the neck mold is 210 ℃, and the rotating speed of the main machine is 60-80 r/min; the vacuum degree in the double-screw extruder is between 0.06 and 0.08 MPa.

Preferably, the drying condition of the product obtained by blending, extruding and granulating is 80 ℃ for 24 hours.

The working mechanism of the invention is as follows:

firstly, selectively opening unsaturated carbon-carbon double bonds in molecular chains of waste ABS and a chain extender A by using a free radical initiator Azobisisobutyronitrile (AIBN) or Azobisisoheptonitrile (ABVN), grafting the molecular chain of the chain extender A to a main chain of the waste ABS molecule through addition reaction, further performing condensation reaction chain extension by using carboxyl or hydroxyl in the molecular chain of the chain extender A and hydroxyl or carboxyl in the molecular chain of the waste ABS, increasing the length of the molecular chain of the ABS, and realizing the recombination of ABS molecular chain segments; meanwhile, the high-reactivity primary hydroxyl of the chain extender B is subjected to dehydration condensation with terminal hydroxyl or carboxyl remained in a waste ABS molecular chain at high temperature, so that a certain chemical crosslinking point is additionally added on the basis of an ABS molecular chain entanglement network, on one hand, the topological structure of the ABS molecular chain entanglement network in an ABS matrix is changed, the entanglement network is strengthened, and on the other hand, the flexibility and the motion freedom of the molecular chain are reserved because a complete three-dimensional network crosslinking structure is not formed; a small amount of elastomer particles are used for replacing a polybutadiene elastic phase in an ABS molecular chain, so that the toughening effect is achieved; finally obtaining the high value-added ABS reclaimed material with good strength and toughness.

Compared with the prior art, the invention has the following advantages:

the invention can modify and regenerate the waste ABS, is environment-friendly and saves resources; when the waste ABS is modified, the active functional groups of the waste ABS are fully utilized by the selected initiator and the two chain extenders, so that the chain extension efficiency is improved; the molecular weight of the modified ABS reclaimed material is obviously increased, and the molecular chain entanglement network is also strengthened, so that the impact toughness and tensile strength of the waste ABS reclaimed material are greatly improved; meanwhile, the problem of ultraviolet aging of the ABS reclaimed material can be improved to a certain extent because the residual double bonds in the waste ABS are partially consumed. Above-mentioned, the value of old and useless ABS recycle has been showing to have promoted.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a flow chart of the preparation of the modified ABS reclaimed material of the invention.

Detailed Description

The invention is further illustrated with reference to the following figures and examples. It should be noted that, in the present application, the embodiments and the technical features of the embodiments may be combined with each other without conflict. Unless defined otherwise, technical or scientific terms used in the present disclosure should have the ordinary meaning as understood by those of ordinary skill in the art to which the present disclosure belongs. The use of the terms "comprising" or "including" and the like in the present disclosure is intended to mean that the elements or items listed before the term cover the elements or items listed after the term and their equivalents, but not to exclude other elements or items.

The invention provides a modified ABS reclaimed material, which comprises the following raw materials in parts by weight: 100 parts of ABS reclaimed materials, 0.5-2 parts of initiator, 0.5-2 parts of chain extender A, 0.1-1 part of chain extender B and 5-10 parts of toughening agent.

As shown in FIG. 1, the preparation process flow of the modified ABS reclaimed material is as follows:

firstly, crushing and drying the ABS reclaimed material, specifically comprising the following steps: commercially available waste ABS sheets are crushed into particles with the particle size less than 5mm in a crusher and dried in a forced air drying oven at 80 ℃ for 6 hours.

Then, uniformly mixing the crushed and dried ABS reclaimed material with an initiator and a chain extender A, and then carrying out first extrusion granulation and drying, wherein the method specifically comprises the following steps:

uniformly mixing the crushed and dried ABS reclaimed materials, the free radical initiator and the chain extender A in a high-speed mixer to ensure that the free radical initiator and the chain extender A are uniformly attached to or coated on the surface of the ABS granular materials, carrying out reactive melt blending extrusion granulation on the mixture by adopting a double-screw extruder, and drying the mixture in an air blast drying oven at 80 ℃ for 24 hours to obtain the waste ABS primary modified granular materials. The temperature of a feeding section of the extruder is 80-100 ℃, the temperature of the highest temperature section in an extrusion melting mixing section is 170-180 ℃, the temperature of a neck mold is 190 ℃, the rotating speed of a main machine of the extruder is 40-60r/min, a vacuum exhaust system of the extruder is started, and the vacuum degree in the extruder is ensured to be 0.06-0.08 MPa.

And finally, uniformly mixing the waste ABS primary modified granules with the chain extender B and the toughening agent, and then carrying out secondary extrusion granulation and drying, wherein the method specifically comprises the following steps:

uniformly mixing the waste ABS primary modified particles, the chain extender B and the toughening agent in a high-speed mixer to uniformly adhere the ABS particles, the toughening agent and the chain extender B, carrying out reactive melt blending extrusion granulation on the mixture by adopting a double-screw extruder, and drying the mixture in a blast drying oven at 80 ℃ for 24 hours to obtain the modified ABS reclaimed material. The temperature of a feeding section of the extruder is 80-120 ℃, the temperature of the highest temperature section in an extrusion melting mixing section is 190-210 ℃, the temperature of a neck mold is 210 ℃, the rotating speed of a main machine of the extruder is 60-80r/min, a vacuum exhaust system of the extruder is started, and the vacuum degree in the extruder is ensured to be 0.06-0.08 MPa.

In the embodiment, the lower screw rotating speed is adopted, so that the residence time of the extrudate in the extruder can be prolonged, and the reaction probability is increased; vacuum exhaust is adopted in the extrusion process, certain vacuum degree is guaranteed, small molecular gases generated in the reaction extrusion process, particularly water molecules generated in the condensation reaction process can be effectively removed, the chemical reaction in the extrusion process is guaranteed to be effectively carried out, and the internal defects of the extruded particles are reduced; the blending extrusion temperature of the second step is slightly increased, which is beneficial to the rapid proceeding of dehydration condensation reaction.

In a particular embodiment, the initiator is azobisisobutyronitrile or azobisisoheptonitrile. The azo initiator has lower reactivity relative to DCP and the like, and free radicals formed by self-cracking at high temperature only have one structural form and mainly attack carbon-carbon double bonds and hardly attack alpha hydrogen atoms or carbon-carbon main chains on the carbon atoms, so that the molecular chain of the waste ABS can be prevented from further breaking under the attack of high temperature and the free radicals, the residual carbon-carbon double bonds on the molecular chain of the waste ABS and the carbon-carbon double bonds on the molecular chain of the chain extender A selected in the invention can be opened, and further collision and free radical addition reaction between the molecular chain segments of the waste ABS and the chain extender A can be achieved through violent random motion of the chain extender A at high temperature, and partial double bonds in the waste ABS can be consumed. The method is not only beneficial to chain extension of waste ABS molecular chains, but also can improve the ultraviolet aging problem of ABS reclaimed materials to a certain extent.

In a specific embodiment, the chain extender a is one or more of ricinoleic acid, itaconic acid, and undecylenic acid, which can be used normally within the processing temperature range employed in the above embodiments. The molecular chain has a common characteristic in chemical structure, namely, one end of the molecular chain contains carboxyl or hydroxyl or both of the carboxyl and the hydroxyl, and the other end of the molecular chain contains unsaturated carbon-carbon double bonds, so that the molecular chain can be subjected to free radical addition reaction with the residual carbon-carbon double bonds in the waste ABS through double bond addition, and can also be subjected to dehydration condensation reaction at high temperature by utilizing the carboxyl or the hydroxyl at the chain end and the hydroxyl or the carboxyl at the chain end of the waste ABS, thereby effectively utilizing the molecular chain of the waste ABS and realizing the extension and recombination of the molecular chain segment. In addition, as the chain extender A is adopted, long-chain alkane exists in the molecular structure, the flexibility of the molecular chain after chain extension is effectively improved, and the improvement of the toughness of the waste ABS is facilitated.

In a specific embodiment, the chain extender B is one or more of trihydroxymethyl propane, glycerol, and erythritol, which can be used normally in the processing temperature range used in the above embodiments. The hydroxyl groups are 3 or more than 3 hydroxyl groups in the molecular chain, and each substance at least contains two primary hydroxyl groups with high condensation reaction activity. Therefore, the substances can be subjected to condensation reaction with a plurality of waste ABS molecular chains still retaining carboxyl or hydroxyl in the second melt blending process, and in addition to further increasing the molecular weight of the waste ABS, a certain number of chemical crosslinking points are introduced into the entanglement network of the waste ABS molecular chains. Because only one end of the molecular chain of the waste ABS usually contains a hydroxyl or carboxyl functional group, the topological structure of the entangled network of the molecular chain of the waste ABS is changed and strengthened on the premise of not forming a three-dimensional crosslinked network. The tensile strength and the elongation at break of the modified ABS reclaimed material can be improved to a certain degree, and meanwhile, the capability of resisting rapid crack growth of a molecular chain entangled network can also be improved. In a specific embodiment, the toughening agent is one or more of nitrile rubber, ethylene propylene diene monomer rubber and styrene butadiene rubber. The rubber elastic phase is added into the modified system to replace a polybutadiene block structure which is partially consumed in a waste ABS molecular chain segment due to chain extension, so that an effective toughening effect can be achieved.

Example 1

A preparation method of a modified ABS reclaimed material comprises the following steps:

1. crushing and drying ABS reclaimed material

Firstly, commercially available waste ABS sheets are put into a grinder to be ground into particles with the particle size of less than 5mm, and the particles are dried in a forced air drying oven at the temperature of 80 ℃ for 6 hours.

2. Uniformly mixing the ABS reclaimed material, the initiator and the chain extender A, performing primary extrusion granulation and drying

According to the formula of the modified ABS reclaimed material: 100 parts of ABS reclaimed materials, 0.5 part of Azodiisobutyronitrile (AIBN), 1.5 parts of ricinoleic acid, 0.7 part of trihydroxy methyl propane and 10 parts of nitrile rubber. Firstly, uniformly mixing the crushed and dried ABS reclaimed materials, azodiisobutyronitrile and ricinoleic acid in a high-speed mixer to uniformly coat a free radical initiator and a chain extender A on the surface of ABS granules, carrying out reactive melt blending extrusion granulation on the mixture by adopting a double-screw extruder, and drying the mixture in an air blast drying oven at 80 ℃ for 24 hours to obtain the waste ABS primary modified granules. The temperature of each section from the feeding section to the neck mold of the extruder is as follows in sequence: 80 ℃, 100 ℃, 150 ℃, 175 ℃, 190 ℃, 40r/min of the rotation speed of the extruder main engine and 0.08MPa of the extrusion vacuum degree.

3. Uniformly mixing the ABS primary modified granules, the chain extender B and the toughening agent, performing secondary extrusion granulation and drying

Uniformly mixing the waste ABS primary modified granular material, trihydroxy methyl propane and nitrile rubber in a high-speed mixer, carrying out reactive melt blending extrusion granulation on the mixture by adopting a double-screw extruder, and drying for 24 hours at 80 ℃ in a forced air drying oven to obtain the modified ABS reclaimed material. The temperature of each section from the feeding section to the neck mold of the extruder is as follows in sequence: 110 ℃, 130 ℃, 170 ℃, 210 ℃, 75r/min of the rotating speed of the extruder host and 0.08MPa of extrusion vacuum degree.

Example 2

Different from the example 1, the modified ABS regrind formulation of this example is: 100 parts of ABS reclaimed materials, 0.5 part of Azobisisoheptonitrile (ABVN), 1.5 parts of ricinoleic acid, 0.7 part of trihydroxy methyl propane and 10 parts of styrene butadiene rubber.

Example 3

Different from the example 1, the modified ABS regrind formulation of this example is: 100 parts of ABS reclaimed materials, 1 part of Azobisisobutyronitrile (AIBN), 1 part of ricinoleic acid, 0.1 part of trihydroxy methyl propane and 8 parts of nitrile rubber.

Example 4

Different from the example 1, the modified ABS regrind formulation of this example is: 100 parts of ABS reclaimed materials, 2 parts of Azobisisobutyronitrile (AIBN), 0.5 part of ricinoleic acid, 1 part of trihydroxy methyl propane and 5 parts of nitrile rubber.

Example 5

Different from the example 1, the modified ABS regrind formulation of this example is: 100 parts of ABS reclaimed materials, 0.5 part of Azodiisobutyronitrile (AIBN), 1.5 parts of undecylenic acid, 0.7 part of trihydroxy methyl propane and 10 parts of nitrile rubber.

Example 6

Different from the example 1, the modified ABS regrind formulation of this example is: 100 parts of ABS reclaimed materials, 0.5 part of Azobisisobutyronitrile (AIBN), 2 parts of ricinoleic acid, 0.1 part of trihydroxy methyl propane and 8 parts of nitrile rubber.

Example 7

Different from the example 1, the modified ABS regrind formulation of this example is: 100 parts of ABS reclaimed materials, 0.5 part of Azodiisobutyronitrile (AIBN), 1 part of ricinoleic acid, 0.7 part of glycerol and 8 parts of styrene butadiene rubber.

Example 8

Different from the example 1, the modified ABS regrind formulation of this example is: 100 parts of ABS reclaimed materials, 0.5 part of Azodiisobutyronitrile (AIBN), 1 part of ricinoleic acid, 0.7 part of trihydroxy methyl propane and 8 parts of ethylene propylene diene monomer.

Example 9

Different from the example 1, the modified ABS regrind formulation of this example is: 100 parts of ABS reclaimed materials, 0.5 part of Azodiisobutyronitrile (AIBN), 0.5 part of ricinoleic acid, 0.5 part of itaconic acid, 0.5 part of undecylenic acid, 0.5 part of trihydroxy methyl propane, 0.2 part of glycerol, 0.1 part of erythritol, 5 parts of butadiene styrene rubber, 2 parts of nitrile rubber and 3 parts of ethylene propylene diene monomer.

Example 10

Different from the embodiment 1, the basic process parameters of the first step of the embodiment are as follows: the temperature of each section from the feeding section to the neck mold of the extruder is as follows in sequence: the extrusion vacuum degree is 0.08MPa, and the extrusion temperature is 115 ℃, 165 ℃, 180 ℃, 190 ℃, the rotation speed of the extruder host is 60 r/min. The second step is that the basic technological parameters are as follows: the temperature of each section from the feeding section to the neck mold of the extruder is as follows in sequence: 115 ℃, 140 ℃, 180 ℃, 210 ℃, the rotating speed of a main machine of the extruder is 80r/min, and the extrusion vacuum degree is 0.08 MPa.

Example 11

Different from the embodiment 1, the basic process parameters of the first step of the embodiment are as follows: the temperature of each section from the feeding section to the neck mold of the extruder is as follows in sequence: 80 ℃, 95 ℃, 140 ℃, 165 ℃, 170 ℃, 190 ℃, 40r/min of the rotating speed of the extruder host and 0.08MPa of extrusion vacuum degree. The second step is that the basic technological parameters are as follows: the temperature of each section from the feeding section to the neck mold of the extruder is as follows in sequence: 105 ℃, 125 ℃, 165 ℃, 190 ℃, 210 ℃, 60r/min of the main machine of the extruder, and 0.08MPa of extrusion vacuum degree.

Comparative example 1

1. Crushing and drying ABS reclaimed material

2. Carrying out primary extrusion granulation and drying on the ABS reclaimed material

And (3) putting 100 parts of ABS reclaimed materials into a high-speed mixer, carrying out reactive melt blending extrusion granulation on the ABS reclaimed materials by adopting a double-screw extruder, and putting the ABS reclaimed materials into a blast drying oven to dry for 24 hours at the temperature of 80 ℃ to obtain the waste ABS primary modified granular materials. The temperature of each section from the feeding section to the neck mold of the extruder is as follows in sequence: 80 ℃, 100 ℃, 150 ℃, 175 ℃, 190 ℃, 40r/min of the rotation speed of the extruder main engine and 0.08MPa of the extrusion vacuum degree.

3. Carrying out secondary extrusion granulation and drying on the ABS primary modified granules

Putting the waste ABS primary modified granules into a high-speed mixer, carrying out reactive melt blending extrusion granulation on the granules by adopting a double-screw extruder, and drying the granules in a forced air drying oven at 80 ℃ for 24 hours to obtain the modified ABS reclaimed material. The temperature of each section from the feeding section to the neck mold of the extruder is as follows in sequence: 110 ℃, 130 ℃, 170 ℃, 210 ℃, 75r/min of the rotating speed of the extruder host and 0.08MPa of extrusion vacuum degree.

Comparative example 2

Unlike comparative example 1, this comparative example added 10 parts of nitrile rubber to the high-speed mixer during the second extrusion granulation.

Comparative example 3

Unlike comparative example 1, this comparative example added 1.5 parts ricinoleic acid to the high-speed mixer at the time of first extrusion granulation.

Comparative example 4

Unlike comparative example 3, this comparative example added 0.5 parts of azobisisobutyronitrile to the high-speed mixer at the time of the first extrusion granulation.

Comparative example 5

Unlike comparative example 4, this comparative example added 10 parts of nitrile rubber to the high mixer at the second extrusion pelletization.

Comparative example 6

Unlike comparative example 1, in this comparative example, 0.7 parts of trimethylolpropane was added to the high-speed mixer during the second extrusion granulation.

And (3) carrying out mechanical property test on the modified ABS reclaimed materials prepared in the examples and the comparative examples, wherein an electronic universal tester is used for carrying out tensile test according to GB/T1040.2-2006 test standards, and the tensile rate is 50 mm/min. Adopting dumbbell specimen with gauge length of 50mm and size of 150X 10X 4mm³Each set of experimental formulas tested 5 splines and the test results averaged. According to the GB/T1843-2008 test standard, firstly, an electric notch sampling machine is used for carrying out V-shaped notch processing on an impact sample strip. And (5) carrying out a cantilever beam impact experiment on the notched impact sample strip by using an impact tester. Each set of samples was tested under a cantilever beam with a pendulum energy of 2.75J and an impact sample specification of 80X 10X 4mm³The depth of the V-shaped notch is 2mm, 5 sample bars are tested in each group of experimental formula, the testing temperature is room temperature, and the testing results are averaged. The mechanical property test results are shown in table 1:

TABLE 1 mechanical Property test results

The molecular weight of the modified ABS reclaimed material is obviously increased, and the molecular chain entanglement network strength is obviously improved. As can be seen from Table 1, the modified ABS reclaimed material of the invention has the advantages of improved tensile property, obviously improved impact toughness, obvious improvement and improved ABS recycling value. Compared with the method of singly modifying by using a toughening agent or singly modifying by using a certain chain extender, the method has better modification effect.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The modified ABS reclaimed material is characterized by comprising the following raw materials in parts by weight: 100 parts of ABS reclaimed materials, 0.5-2 parts of initiator, 0.5-2 parts of chain extender A, 0.1-1 part of chain extender B and 5-10 parts of toughening agent.

2. The modified ABS regrind according to claim 1, wherein the initiator is an initiator capable of selectively initiating homolytic cleavage of unsaturated carbon-carbon double bonds and free radical addition reaction.

3. The modified ABS regrind according to claim 2, wherein the initiator is azobisisobutyronitrile or azobisisoheptonitrile.

4. The modified ABS regrind according to claim 1, wherein the chain extender A is a small molecule compound containing a terminal hydroxyl group and/or a carboxyl group and having an unsaturated carbon-carbon double bond; the chain extender B is a small molecular compound containing three or four hydroxyl groups and at least two primary hydroxyl groups.

5. The modified ABS regrind according to claim 4, wherein the chain extender A is one or more of ricinoleic acid, itaconic acid and undecylenic acid; the chain extender B is one or more of trihydroxy methyl propane, glycerol and erythritol.

6. The modified ABS regrind according to claim 1, wherein the toughening agent is a rubber elastomer.

7. The modified ABS regrind according to claim 6, wherein the toughening agent is one or more of nitrile rubber, ethylene propylene diene monomer and styrene butadiene rubber.

8. A method for preparing the modified ABS reclaimed material as described in any one of claims 1-7, which comprises the following steps: crushing and drying the ABS reclaimed material for later use; carrying out reactive melt blending extrusion granulation on the crushed and dried ABS reclaimed material, an initiator, a chain extender A, a chain extender B and a toughening agent; and drying the product obtained by blending, extruding and granulating to obtain the modified ABS reclaimed material.

9. The preparation method of the modified ABS reclaimed material as claimed in claim 8, wherein a twin-screw extruder is used for reactive melt blending extrusion granulation, and the extrusion granulation is carried out twice, specifically: uniformly mixing the crushed and dried ABS reclaimed materials with an initiator and a chain extender A, then carrying out first extrusion granulation and drying to obtain a process product, and then continuously uniformly mixing the process product with a chain extender B and a toughening agent, and then carrying out second extrusion granulation.

10. The preparation method of the modified ABS reclaimed material according to claim 9, wherein the steps of crushing and drying the ABS reclaimed material comprise: putting the ABS reclaimed material into a grinder to be ground into particles with the particle size less than 5mm, and then drying the ground ABS reclaimed material for 5-8 hours at the temperature of 60-80 ℃;

during first extrusion granulation, the temperature of a feeding section of the double-screw extruder is 80-100 ℃, the temperature of the highest temperature section in an extrusion melting mixing section is 170-180 ℃, the temperature of a neck ring mold is 190 ℃, and the rotating speed of a main machine is 40-60 r/min; the vacuum degree in the double-screw extruder is between 0.06 and 0.08 MPa;

during the second extrusion granulation, the temperature of the feeding section of the double-screw extruder is 80-120 ℃, the temperature of the highest temperature section in the extrusion melting mixing section is 190-210 ℃, the temperature of the neck ring mold is 210 ℃, and the rotating speed of the main machine is 60-80 r/min; the vacuum degree in the double-screw extruder is between 0.06 and 0.08 MPa.