ABS is one of the five major synthetic resins, with excellent impact resistance, heat resistance, low temperature resistance, chemical resistance, and electrical properties. It also has characteristics such as easy processing, stable product size, and good surface gloss. It is easy to paint and color, and can also be used for secondary processing such as surface spraying metal, electroplating, welding, hot pressing, and bonding. It is widely used in industrial fields such as machinery, automobiles, electronic appliances, instruments, textiles, and construction, It is a widely used thermoplastic engineering plastic.

ABS material, also known as ABS engineering plastics, is opaque and ivory granular material. Its products can be painted in various colors and have high gloss. ABS has a relative density of around 1.05 and low water absorption. ABS has good adhesion with other materials, making it easy for surface printing, coating, and plating treatment. ABS has an oxygen index of 18 to 20 and is a flammable polymer with a yellow flame, black smoke, and a special odor.

Processing control when ABS contains other materials

ABS contains PC, PBT, PMMA, AS, etc., which is relatively easy and can be used for PC/ABS alloys, ABS modification, etc;

ABS contains HIPS, which is also a headache when making secondary materials. The main reason is that the materials are relatively brittle, so it is possible to choose a suitable phase solvent to make PC alloy;

ABS contains PET or low-temperature PET (PCTA), which is also a headache when making secondary materials. The main reason is that the materials are relatively brittle and the effect of adding toughening agents is not obvious; So it is not recommended to purchase this material for modification factories.

2. Regeneration ABS modification, selection and control of additives

For PVC/ABS alloys that are currently being made extensively, it is recommended to use relatively pure ABS and adjust the corresponding additives based on their toughness and related properties;

For the re granulation of fire-resistant ABS recycled materials, it is necessary to consider whether to add toughening agents and fire retardants based on the material's performance and fire resistance requirements. At the same time, the processing temperature should be appropriately reduced;

For toughening ABS, toughening agents such as high rubber powder, EVA, elastomer, etc. are used according to physical properties and requirements;

For high gloss ABS materials, not only PMMA composites but also PC, AS, PBT composites can be considered, and relevant additives can be selected to produce materials that meet the requirements;

For the production of ABS fiber reinforced materials, it is best not to simply pass through the machine for some recycled ABS fiber reinforced materials, as this will cause a significant decrease in physical properties. It is best to add some new materials, glass fibers, and related additives.

For ABS/PC alloys, it is mainly necessary to choose the appropriate PC viscosity, appropriate phase solvents, toughening agent types, and reasonable combinations for this type of material.

Summary of Common Issues with 3 Regenerated ABS and High gloss ABS

① How to handle ABS electroplating material to ensure material quality?

There are two basic methods for ABS electroplating, one is vacuum spraying, and the other is solution electroplating. The general treatment method is to remove the metal plating layer by etching with an acid alkali salt solution. However, this method largely damages the properties of B (butadiene) rubber in ABS materials, resulting in poor toughness and apparent quality of the final product.

In order to avoid this consequence, two main methods are currently adopted: one is to break the electroplated ABS parts and directly melt and extrude them, by using a high mesh filter to filter these electroplated layers. Although the original performance of the material is retained to some extent, this method requires a high frequency of filter replacement.

In recent years, efforts have been made to develop low pH solution soaking methods, but the results are not ideal. The most effective method is to dissolve the electroplating layer in a neutral or slightly acidic solution by replacing the metal of the electroplating layer, in order to obtain the detached ABS fragmentation.

② What is the difference between ABS material and ASA material? Can it be mixed for use?

The full name of ASA material is acrylonitrile styrene acrylate terpolymer, which differs from ABS only in that the rubber component is acrylic rubber rather than butadiene rubber. ASA material, due to its better thermal and light stability properties compared to ABS material due to its rubber composition, has replaced the use of ABS in many situations with high aging requirements. These two materials are to some extent compatible and can be directly mixed into particles.

③ Why is ABS material broken with one side yellow and one side white?

This is mainly caused by ABS products being exposed to sunlight for a long time. Because the butadiene rubber (B) in ABS materials gradually damages and discolors under long-term sunlight and thermal oxidation, the overall color of the material turns yellow and dark.

④ What should be paid attention to when crushing and pelletizing ABS boards?

The viscosity of ABS board materials is higher than that of ordinary ABS materials, and attention should be paid to increasing the processing temperature appropriately during processing. In addition, due to the low stacking density of board planing, it is necessary to undergo drying treatment before processing, and it is best to have a forced compression feeding process during the processing to ensure the quality and output of the product.

⑤ What should I do if there is a problem of drying and water splashing during the injection molding process of ABS recycled materials?

The main reason for water splashes in ABS material injection molding is that the moisture in the ABS material has not been fully dried. The exhaust during the granulation process is the main reason for the drying failure of the material. ABS material itself has a certain degree of water absorption, but this moisture can be removed by hot air drying. However, if regenerated particles do not receive good exhaust during the granulation process, they are likely to retain residual moisture inside the particles.

This moisture needs to be dried, and it takes a long time. If ordinary drying procedures are used, it is natural for the material to not dry. To solve this problem, it is mainly necessary to start with melt extrusion granulation and improve the exhaust conditions during the melt extrusion process to avoid residual moisture inside the particles.

⑥ Foaming often occurs in the granulation of light colored flame-retardant ABS, and how to deal with graying out?

This situation often occurs in situations where the temperature control of melt extrusion equipment is poor. The common flame retardant ABS has poor heat resistance due to its flame retardant components. Improper temperature control during secondary recycling can easily lead to decomposition, foaming, and discoloration. This situation is generally solved by adding a certain amount of heat stabilizer. There are two common types of additives, stearate and hydrotalcite.

⑦ What is the reason for the delamination phenomenon after adding toughening agents to ABS granulation?

For the toughening of ABS, not all common toughening agents on the market can be used. For example, SBS (poly (styrene butadiene styrene) triblock copolymer), although SBS has the same structure as ABS, the compatibility between the two is not ideal. A small amount of addition can improve the toughness of ABS materials to a certain extent. However, if the addition ratio exceeds a certain level, stratification will occur. It is recommended to consult the supplier to obtain a matching toughening agent.

⑧ Is the commonly heard alloy PC (polycarbonate)/ABS alloy?

Alloy material refers to a mixture formed by mixing two different polymers. This mixture not only has the unique properties of the two materials themselves, but also has some new characteristics that the two do not have. Due to this advantage, polymer alloys are a significant material group in the plastic industry. PC (polycarbonate)/ABS alloy is only a specific material in this group. However, due to the widespread use of PC (polycarbonate)/ABS alloys in the electrical industry, it is customary to use alloys to refer to PC (polycarbonate)/ABS alloys. Strictly speaking, PC (polycarbonate)/ABS alloy is an alloy, but the alloy is not just PC (polycarbonate)/ABS alloy.

⑨ What is high gloss ABS? What issues should be noted when recycling?

High gloss ABS is essentially the introduction of MMA (methacrylate) into ABS resin. Due to the fact that the glossiness of MMA is much better than that of ABS itself, and its surface hardness is also higher than that of ABS. Especially suitable for making thin-walled large products such as flat panel TV panels, high-definition TV panels, and bases. At present, the quality level of high gloss ABS in China varies, and attention should be paid to the toughness, luster, and surface hardness of the material when recycling. Generally speaking, materials with high flow, good toughness, and high surface hardness have higher recycling value.

⑩ Someone on the market is selling ABS/PET (polyethylene terephthalate) materials. Can these two materials be mixed with each other? How to sort?

The basic principle of ABS/PET (polyethylene terephthalate) sold on the market is to add a certain proportion of PET (polyethylene terephthalate) to ABS materials and adjust their affinity by adding compatibilizers. This is a material that modification companies intend to develop in order to obtain materials with new physical and chemical properties.

It is not suitable to do this work during ABS recycling. Moreover, the common equipment used in the recycling process is a single screw extruder, which has a much lower mixing capacity than the twin screw extruders used in the modification industry. In the ABS recycling process, it is still better to separate PET (polyethylene terephthalate) material from the ABS material.

What material is ABS bathtub material? How should this be recycled?

ABS bathtub material is actually a co extruded material of ABS and PMMA (Polymethyl Methacrylate). Due to the higher surface gloss and hardness of PMMA (Polymethyl Methacrylate), during the production of bathtubs, manufacturers consciously extrude another layer of PMMA (Polymethyl Methacrylate) material on the surface of ABS extruded profiles.

Recycling this type of material does not require sorting. Because PMMA (Polymethyl Methacrylate) has good compatibility with ABS materials, the crushed material can be directly mixed, melted, and extruded. Of course, in order to improve the toughness of the material, a certain proportion of toughening agent needs to be added. This can vary from 4 to 10% depending on the product requirements.

Source: Environmental Leadership Circle