PC / PS composite carrier tape recycled plastic modified polymer alloy and preparation method thereof

Abstract

The invention discloses a PC / PS composite carrier tape recycled plastic modified polymer alloy and a preparation method thereof.The modified polymer alloy comprises 85-95 wt% of PC / PS composite carrier tape recycled plastic, 3-10 wt% of a first polymer, 1-5 wt% of a second polymer and 1-5 wt% of a third polymer, the first polymer is used for improving the mechanical property, heat resistance and melt index of PC in the recycled material, and the second polymer is used for improving the mechanical property, heat resistance and melt index of PC in the recycled material; the second polymer is used for improving the compatibility of the PC / PS alloy and increasing the toughness of the material, and the third polymer is used for reducing the negative influence of the conductive carbon black on the impact property and the elongation at break of the recycled plastic.

Description

Technical Field

[0001] The present invention relates to the technical field of recycled plastic modification, and in particular to a PC / PS composite carrier recycled plastic modified polymer alloy and a preparation method thereof. Background Art

[0002] Plastic carrier tape refers to a strip product made of PC, PS, ABS and other plastics used in the field of electronic component packaging. It is mainly used to package electronic components and prevent them from being damaged by static electricity. The market demand is huge. Most of the plastic carrier tapes used for conductivity and antistatic are formed by extrusion of conductive PS and PC plastics, and form a sandwich structure with conductive PS on the upper and lower surface layers and PC in the middle layer. This structure makes it difficult to separate PC and PS plastics for recycling. The main reason is that PC is very easy to degrade during the heat processing process and has poor compatibility with PS. Conductive PS contains about 20% conductive carbon black, which makes the mechanical properties of PC / PS composite plastics after recycling and granulation poor, greatly limiting the recycling of such recycled plastics and causing great waste of plastic resources.

[0003] In order to better recycle and reuse the PC middle layer of this carrier, the plastic composite carrier needs to be blended and modified to meet the GB standard test requirements of tensile strength greater than 45MPa, tensile fracture nominal strain greater than 35%, bending strength greater than 70MPa, notched impact strength greater than 25Kj / m^2, heat deformation temperature greater than 105℃, melt index less than 15 (260℃ / 2.16kg), etc. In order to meet these technical indicators, the following technical problems need to be solved in production:

[0004] (1) Improve the performance of PC plastics that have been degraded after multiple processing;

[0005] (2) The improvement of PC / PS compatibility improves the tensile strength, flexural strength, notched impact strength and tensile fracture nominal strain of the material;

[0006] (3) Reduce the negative impact of conductive carbon black on the notched impact strength and tensile fracture nominal strain of PC / PS polymer alloys.

[0007] The applicant has consulted a large number of existing patent documents and has not yet found a technical solution that can effectively solve the above three technical problems at the same time.

[0008] for example:

[0009] 1. In response to the above technical problem (1), patent CN2014101223539 discloses a polycarbonate chain extender containing fluorene groups and silicon-oxygen structures and a preparation method thereof, which solves the defect that the molecular weight of recycled PC plastics decreases due to degradation, causing a significant decrease in comprehensive performance, and can significantly improve the mechanical properties and processing properties of recycled PC plastics. This type of chain extender is beneficial for improving the impact properties of PC, especially low-temperature impact resistance, but the introduction of Si-O structure will reduce the tensile strength, bending strength and polarity of the material.

[0010] 2. In response to the above technical problem (2), patent CN2020111126526 discloses a polycarbonate / polystyrene alloy, which reduces dielectric loss by selecting polystyrene with a specific rubber distribution particle size and adding a carboxylic acid-based ionomer to change the structure of the polycarbonate and polystyrene alloy; publication number CN114230998A0 discloses a PC / PS / PMMA ternary alloy material and a preparation method thereof, which uses a mixture of tricaprolactam phosphite and glycidyl methacrylate in a weight ratio of 2.3-3:1.2-1.5 as a compatibilizer to improve the scratch resistance and wear resistance of the alloy; publication number CN105820 529A discloses a polycarbonate and polystyrene alloy material and a preparation method thereof, using compatibilizers such as PS-g-GMA, PS-g-MAH, and SEBS-g-MAH to improve the processing fluidity and impact resistance of the alloy material; Publication No. CN117986834A discloses a PC / PS composite material and a preparation method thereof, using a first compatibilizer of polyphenylene ether-maleic anhydride grafted polymer (PPO-g-MAH) and SEBS-g-MAH, and a second compatibilizer of styrene grafted glycidyl methacrylate (SAN-g-GMA) to effectively improve the hardness, solvent resistance, compatibility, and fluidity of the PC / PS material. These four patents are only PC / PS compatibility improvement methods proposed based on the uses of their respective inventions, and cannot simultaneously improve the tensile strength, flexural strength, notched impact strength, and tensile fracture nominal strain of the PC / PS polymer alloy;

[0011] 3. In view of the above technical problem (3), publication number CN105694409A discloses using a mixture of methyl methacrylate-butadiene-styrene copolymer and acrylonitrile-butadiene-styrene copolymer in a ratio of 1:1 to toughen carbon black conductive PC, but these two toughening agents themselves do not contain chemically active groups and do not improve the affinity for organic material PC and inorganic material carbon black; patent CN2014101959294 and publication number CN103073870A disclose using small molecule surfactants and coupling agents to treat conductive carbon black to increase the affinity between conductive carbon black and organic material PC, but these small molecule additives are prone to cause die carbon deposition during carrier production; patent CN20201112228996 discloses a carrier Conductive polycarbonate composition for tape and carrier tape made thereof, the composition comprises: polycarbonate, conductive carbon black, a first polymer, a third polymer and an additive, the first polymer is a thermoplastic polyester, the third polymer is a binary or ternary copolymer of ethylene, glycidyl methacrylate and acrylate, the invention achieves low surface resistivity of the composite molded carrier tape, greatly reduced surface bumps, significantly improved impact strength, high toughness, clear storage hole molding, and improved melt fluidity of the material, making the surface texture of the molded carrier tape smoother and more delicate, improving the apparent quality, and improving the sealing tension of the carrier tape and the cover tape under the condition of low conductive carbon black addition amount by adding the first, second and third polymers; but according to the Igetabond disclosed by Sumitomo Corporation of Japan TM The binary or ternary copolymers of ethylene, glycidyl methacrylate and acrylate, because they have epoxy groups, will show obvious gelation when melt-mixed with polymers having functional groups with high reactivity with epoxy groups (such as carbonate bonds of polycarbonate). The gel particles will cause convex spots on the surface of the product and reduce the appearance quality. Summary of the invention

[0012] In order to overcome the above-mentioned deficiencies and disadvantages of the prior art, a technical solution adopted by the present invention is as follows:

[0013] PC / PS composite carrier recycled plastic modified polymer alloy, comprising the following components in percentage by weight:

[0014] PC / PS composite carrier recycled plastic, accounting for 85-95wt%,

[0015] The first polymer is a polyester containing an ester bond structure and a small amount of epoxy structure, and its mass accounts for 3-10wt%;

[0016] The second polymer is a weakly polar thermoplastic elastomer containing a polystyrene structure, and its mass accounts for 1-5wt%;

[0017] The third polymer is a strongly polar thermoplastic elastomer containing a hydrogen bond structure, and its mass accounts for 1-5wt%.

[0018] As a further elaboration of the above technical solution:

[0019] In the above technical scheme, the first polymer is obtained by melt blending and reacting substance A and substance B in a mass ratio of 6:4 to 8:2 through a twin-screw extruder: the substance A is polybutylene terephthalate (PBT) or polyethylene terephthalate (PET) or poly-1,4-cyclohexanedimethanol terephthalate (PCT) or polytrimethylene terephthalate (PTT), and the substance B is ethylene-glycidyl methacrylate copolymer (E-GMA) or ethylene-methyl methacrylate-glycidyl methacrylate copolymer (E-MA-GMA) or ethylene-butyl methacrylate-glycidyl methacrylate copolymer (E-BA-GMA).

[0020] In the above technical solution, the second polymer is a maleic anhydride (MAH) grafted product of SBS or SEBS, with a grafting rate of 0.6-1.2%, obtained by melt blending SBS or SEBS with maleic anhydride in a twin-screw extruder.

[0021] In the above technical solution, the third polymer is thermoplastic polyurethane elastomer (TPU) or thermoplastic polyamide elastomer (TPAE).

[0022] A technical solution adopted by the present invention is as follows:

[0023] The preparation method of the PC / PS composite carrier recycled plastic modified polymer alloy is used to prepare the PC / PS composite carrier recycled plastic modified polymer alloy described in the above technical scheme, and the preparation method comprises the following steps:

[0024] Step S1-preparing the first polymer: firstly, the polyester resin and the copolymer containing the GMA group are mixed in a mass ratio of 6:4 to 8:2 and mixed evenly in a high-speed mixing cylinder, and then melt-blended and extruded into granules through a first twin-screw extruder;

[0025] Step S2-preparing the second polymer: MAH, initiator and SBS or SEBS are mixed in a high-speed mixing cylinder according to a proportion, and melt-blended and extruded into granules through a second twin-screw extruder;

[0026] Step S3-mixing modification: the recycled plastic of the PC / PS composite carrier, the first polymer, the second polymer and the third polymer are mixed in a high-speed mixing cylinder according to a proportion, and then melt-blended and extruded into granules through a third twin-screw extruder.

[0027] As a further elaboration of the above technical solution:

[0028] In the above technical solution, the aspect ratio of the twin screws in the first twin screw extruder in step S1 is between 36:1 and 40:1, the extrusion temperature is between 200°C and 240°C, the screw speed is maintained at 80% to 90% of the rated speed, and the motor current is maintained at 80% to 90% of the rated current;

[0029] In the above technical solution, the aspect ratio of the twin screws in the first twin screw extruder in step S2 is between 44:1 and 48:1, the extrusion temperature is between 180°C and 230°C, the screw speed is maintained at 80% to 90% of the rated speed, and the motor current is maintained at 80 to 90% of the rated current;

[0030] In the above technical solution, the aspect ratio of the twin screw in the third twin-screw extruder in step S3 is between 36:1 and 40:1, the extrusion temperature is between 200°C and 240°C, the screw speed is maintained at 80% to 90% of the rated speed, and the motor current is maintained at 80 to 90% of the rated current.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The first polymer in the present invention is a polyester containing an ester bond structure and a small amount of epoxy groups. The ester bond structure of polyester is more stable than the carbonate bond structure in polycarbonate. It will not cause a gel reaction when it reacts chemically with the GMA copolymer in a molten state, and at the same time dilutes the concentration of epoxy groups in the polymer. In this way, the small amount of epoxy groups in the first polymer can not only play a role in chain extension of PC in the recycled material and increase the molecular weight of PC in the recycled material, but also will not cause an obvious gel reaction, which can greatly improve the mechanical properties, heat resistance and melt index of PC in the recycled material and reduce the risk of convex points on the surface of the product;

[0033] 2. The second polymer in the present invention is a weakly polar thermoplastic elastomer containing a polystyrene structure. The styrene segment of this type of polymer has good compatibility with PS. After grafting with maleic anhydride, it has good compatibility with PC, which can improve the compatibility of PC / PS alloys and increase the toughness of the material.

[0034] 3. The third polymer in the present invention is a thermoplastic elastomer containing hydrogen bonds. The thermodynamic incompatibility between the soft and hard segments of the elastomer leads to microphase separation in different forms. It has both the elasticity of rubber and the toughness of the polymer. It has better affinity with the conductive carbon black in the carrier recycled plastic, so that the conductive carbon black in the recycled plastic is enriched in the recycled plastic after melt mixing, reducing the negative impact of the conductive carbon black on the impact properties and elongation at break of the recycled plastic;

[0035] 4. The present invention introduces the first, second and third polymers into the modified formula and makes them into a PC / PS composite carrier recycled plastic modified polymer alloy, so that the mechanical properties can be greatly improved. When tested according to GB standard, the tensile strength is greater than 45MPa, the nominal strain at tensile break is greater than 35%, the bending strength is greater than 70MPa, the notched impact strength is greater than 25Kj / m^2, the heat deformation temperature is greater than 105°C, and the melt index is less than 15 (test condition 260°C / 2.16 kg). A single modification operation can improve the mechanical properties of the PC / PS composite carrier recycled plastic, so that it meets the performance requirements of secondary reuse and saves plastic resources. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below.

[0037] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, "several" and "multiple" mean two or more, unless otherwise clearly and specifically defined. In this application, unless otherwise clearly defined and defined, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In this application, unless otherwise clearly defined and defined, the first feature "above" or "below" the second feature may include the first and second features directly contacting, or the first and second features not directly contacting but contacting through another feature between them. Moreover, the first feature being “above”, “above” and “above” the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being “below”, “below” and “below” the second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0038] The present invention discloses a PC / PS composite carrier recycled plastic modified polymer alloy, comprising the following components in weight percentage:

[0039] PC / PS composite carrier recycled plastic, accounting for 85-95wt%,

[0040] The first polymer is a polyester containing an ester bond structure and a small amount of epoxy structure, and its mass accounts for 3-10wt%;

[0041] The second polymer is a weakly polar thermoplastic elastomer containing a polystyrene structure, and its mass accounts for 1-5wt%;

[0042] The third polymer is a strongly polar thermoplastic elastomer containing a hydrogen bond structure, and its mass accounts for 1-5wt%.

[0043] Specifically, the first polymer is obtained by melt blending and reacting substance A and substance B in a mass ratio of 6:4 to 8:2 through a twin-screw extruder: substance A is polybutylene terephthalate (PBT) or polyethylene terephthalate (PET) or poly 1,4-cyclohexanedimethanol terephthalate (PCT) or polypropylene terephthalate (PTT), and substance B is ethylene-glycidyl methacrylate copolymer (E-GMA) or ethylene-methyl methacrylate-glycidyl methacrylate copolymer (E-MA-GMA) or ethylene-butyl methacrylate-glycidyl methacrylate copolymer (E-BA-GMA).

[0044] Specifically, the second polymer is a maleic anhydride (MAH) grafted product of SBS or SEBS, with a grafting rate of 0.6-1.2%, obtained by melt blending SBS or SEBS with maleic anhydride in a twin-screw extruder.

[0045] Specifically, the third polymer is thermoplastic polyurethane elastomer (TPU) or thermoplastic polyamide elastomer (TPAE). To reduce costs, these elastomers can be recycled from textile products, food packaging, etc.

[0046] The present invention also discloses a method for preparing a polymer alloy modified by recycling plastic from a PC / PS composite carrier, which is used to prepare the polymer alloy modified by recycling plastic from a PC / PS composite carrier in the above embodiment. The preparation method comprises the following steps:

[0047] Step S1-preparing the first polymer: firstly, the polyester resin and the copolymer containing the GMA group are mixed in a mass ratio of 6:4 to 8:2 and mixed evenly in a high-speed mixing cylinder, and then melt-blended and extruded into granules through a first twin-screw extruder;

[0048] Step S2-preparing the second polymer: MAH, initiator and SBS or SEBS are mixed in a high-speed mixing cylinder according to a proportion, and melt-blended and extruded into granules through a second twin-screw extruder;

[0049] Step S3-mixing modification: the recycled plastic of the PC / PS composite carrier, the first polymer, the second polymer and the third polymer are mixed in a high-speed mixing cylinder according to a proportion, and then melt-blended and extruded into granules through a third twin-screw extruder.

[0050] Specifically, in step S1, the aspect ratio of the twin screws in the first twin screw extruder is between 36:1 and 40:1, the extrusion temperature is between 200° C. and 240° C., the screw speed is maintained at 80% to 90% of the rated speed, and the motor current is maintained at 80% to 90% of the rated current;

[0051] Specifically, in step S2, the aspect ratio of the twin screws in the first twin screw extruder is between 44:1 and 48:1, the extrusion temperature is between 180° C. and 230° C., the screw speed is maintained at 80% to 90% of the rated speed, and the motor current is maintained at 80% to 90% of the rated current;

[0052] Specifically, in step S3, the aspect ratio of the twin screw in the third twin screw extruder is between 36:1 and 40:1, the extrusion temperature is between 200°C and 240°C, the screw speed is maintained at 80% to 90% of the rated speed, and the motor current is maintained at 80 to 90% of the rated current.

[0053] The following table lists the mass proportions of PC / PS recycled plastics, the first polymer, the second polymer and the third polymer of different polymer alloys in the three embodiments of the present invention and their mechanical property test data:

[0054] 1. PC / PS composite carrier recycled plastic modified polymer alloy formula table:

[0055]

[0056]

[0057] 2. Mechanical properties test data of PC / PS recycled plastics before and after modification:

[0058]

[0059] From the above test data, it can be seen that the tensile strength, tensile fracture nominal strain percentage, and notched impact strength of the modified PC / PS recycled plastics have been significantly improved, and the mechanical properties have been significantly enhanced. The bending strength and heat deformation temperature have not changed significantly, and the melt index has been significantly reduced, which can meet the GB standard test, tensile strength greater than 45MPa, tensile fracture nominal strain greater than 35%, bending strength greater than 70MPa, notched impact strength greater than 25Kj / m^2, heat deformation temperature greater than 105℃, and melt index less than 15 (test conditions 260℃ / 2.16kg). At the same time, it can also be seen that the mass proportion of PC / PS recycled plastics is proportional to the tensile strength and bending strength after modification, and inversely proportional to the tensile fracture nominal strain, notched impact strength, and melt index; the mass proportion of the first polymer, the second polymer, and the third polymer is inversely proportional to the tensile strength, bending strength, and melt index after modification, and is proportional to the tensile fracture nominal strain and notched impact strength. In the application, the mass of the first polymer, the second polymer, and the third polymer can be selected according to actual needs and combined with their respective characteristics.

[0060] The above does not limit the technical scope of the present invention in any way. Any modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. PC / PS composite carrier recycled plastic modified polymer alloy, characterized by: Contains the following components in weight percentage: PC / PS composite carrier recycled plastic, accounting for 85-95wt%, The first polymer is a polyester containing an ester bond structure and a small amount of epoxy structure, and its mass accounts for 3-10wt%; The second polymer is a weakly polar thermoplastic elastomer containing a polystyrene structure, and its mass accounts for 1-5wt%; The third polymer is a strongly polar thermoplastic elastomer containing a hydrogen bond structure, and its mass accounts for 1-5wt%.

2. The PC / PS composite carrier recycled plastic modified polymer alloy according to claim 1, characterized in that: The first polymer is obtained by melt blending substance A and substance B in a mass ratio of 6:4 to 8:2 through a twin-screw extruder: substance A is polybutylene terephthalate (PBT) or polyethylene terephthalate (PET) or poly-1,4-cyclohexanedimethanol terephthalate (PCT) or polytrimethylene terephthalate (PTT); substance B is ethylene-glycidyl methacrylate copolymer (E-GMA) or ethylene-methyl methacrylate-glycidyl methacrylate copolymer (E-MA-GMA) or ethylene-butyl methacrylate-glycidyl methacrylate copolymer (E-BA-GMA).

3. The PC / PS composite carrier recycled plastic modified polymer alloy according to claim 1, characterized in that: The second polymer is a maleic anhydride (MAH) grafted product of SBS or SEBS, with a grafting rate of 0.6-1.2%, and is obtained by melt blending SBS or SEBS with maleic anhydride in a twin-screw extruder.

4. The PC / PS composite carrier recycled plastic modified polymer alloy according to claim 1, characterized in that: The third polymer is thermoplastic polyurethane elastomer (TPU) or thermoplastic polyamide elastomer (TPAE).

5. A method for preparing a polymer alloy modified by recycling plastic from a PC / PS composite carrier, characterized in that: For preparing the PC / PS composite carrier recycled plastic modified polymer alloy as described in any one of claims 1 to 4, the preparation method thereof comprises the following steps: Step S1-preparing the first polymer: firstly, the polyester resin and the copolymer containing the GMA group are mixed in a mass ratio of 6:4 to 8:2 and mixed evenly in a high-speed mixing cylinder, and then melt-blended and extruded into granules through a first twin-screw extruder; Step S2-preparing the second polymer: MAH, initiator and SBS or SEBS are mixed in a high-speed mixing cylinder according to a proportion, and melt-blended and extruded into granules through a second twin-screw extruder; Step S3-mixing modification: the recycled plastic of the PC / PS composite carrier, the first polymer, the second polymer and the third polymer are mixed in a high-speed mixing cylinder according to a proportion, and then melt-blended and extruded into granules through a third twin-screw extruder.

6. The method for preparing a PC / PS composite carrier recycled plastic modified polymer alloy according to claim 5, characterized in that: In the step S1, the aspect ratio of the twin screws in the first twin screw extruder is between 36:1 and 40:1, the extrusion temperature is between 200°C and 240°C, the screw speed is maintained at 80% to 90% of the rated speed, and the motor current is maintained at 80 to 90% of the rated current.

7. The method for preparing a polymer alloy of recycled plastic modified from a PC / PS composite carrier according to claim 5, characterized in that: In the step S2, the aspect ratio of the twin screws in the first twin screw extruder is between 44:1 and 48:1, the extrusion temperature is between 180°C and 230°C, the screw speed is maintained at 80% to 90% of the rated speed, and the motor current is maintained at 80 to 90% of the rated current.

8. The method for preparing a polymer alloy modified by recycled plastics of a PC / PS composite carrier according to claim 5, characterized in that: In the step S3, the aspect ratio of the twin screws in the third twin screw extruder is between 36:1 and 40:1, the extrusion temperature is between 200°C and 240°C, the screw speed is maintained at 80% to 90% of the rated speed, and the motor current is maintained at 80 to 90% of the rated current.

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