Processing control when other materials are contained in ABS
ABS contains PC, PBT, PMMA, AS, etc., which is relatively easy. It can be used for PC/ABS alloy, ABS modification, etc. It should be noted that it cannot be used for PVC/ABS alloy;
ABS contains HIPS, which is also a headache for secondary materials. The main reason is that the material is relatively brittle. You can consider choosing a suitable compatibilizer to make PC alloy;
ABS contains PET or PCTA, which is also a headache for secondary materials. The main reason is that the materials are relatively brittle and the effect of adding tougheners is not obvious; therefore, it is not recommended to purchase such materials for modification plants.
Selection and Control of Auxiliary Agents in Modification of Recycled ABS
For the PVC/ABS alloys that are made more now, it is recommended to use relatively pure ABS, and adjust the corresponding additives according to the toughness and related performance;
For the re-pumping of fireproof ABS recycled materials, it is necessary to consider whether to increase toughening agents and fire retardants according to the performance and fire resistance requirements of the material. At the same time, the processing temperature is appropriately reduced;
For toughening ABS, use toughening agents according to physical properties and requirements, such as high rubber powder, EVA, elastomers, etc.;
For high-gloss ABS, not only PMMA compounding can be considered, but also PC, AS, PBT, etc. compounding 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 the machine for some ABS regenerated fiber reinforced materials, so the physical properties will be greatly reduced, and it is best to add some materials, glass fiber and related additives.
For ABS/PC alloy, for this type of material, it is mainly to select the appropriate PC viscosity, the appropriate compatibilizer and toughening agent type and reasonable coordination.
Summary of common problems
How to deal with ABS electroplating material to ensure the quality of the material?
There are basically two 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 acid-base salt solution. However, this method largely destroys the performance of B (butadiene) rubber in ABS materials, resulting in poor toughness and apparent quality of the final product.
In order to avoid this consequence, currently two methods are mainly adopted: one is to crush the electroplated ABS parts and directly melt and extrude them, and filter these electroplated layers by using a high-mesh filter screen. Although the original performance of the material is retained to a certain extent, this method requires a high frequency of filter replacement times.
In recent years, we have been vigorously developing low-pH solution soaking methods, but the effect is not satisfactory. The most obvious effect is to dissolve the electroplated layer in a neutral or slightly acidic solution by replacing the metal of the electroplated layer to obtain the deplated ABS broken.
What is the difference between ABS material and ASA material? Can it be mixed?
The full name of ASA material is acrylonitrile-styrene-acrylate terpolymer. The difference from ABS is that the rubber component is acrylic rubber instead of butadiene rubber. ASA material has better thermal stability and light stability than ABS material because of its rubber composition, so it replaces ABS in many occasions with high aging requirements. These two materials are compatible to a certain extent and can be directly mixed into particles.
Why is ABS material broken, one side is yellow and the other side is white?
This is mainly caused by ABS products exposed to light for a long time. Because the butadiene rubber (B) in the ABS material will gradually deteriorate and change color under long-term sunlight and thermal oxidation, the color of the material will become yellow and darker in general.
What should be paid attention to in the crushing and granulation of ABS sheets?
The viscosity of ABS board material is higher than that of ordinary ABS material, so attention should be paid to increase the processing temperature appropriately during processing. In addition, due to the low bulk density of the plank shavings, it needs to be dried before processing, and it is better to have a forced compression feeding process during the processing to ensure the quality and output of the product.
What should I do if the ABS recycled material does not dry out during the injection molding process?
Water splashing in ABS injection molding is mainly due to insufficient drying of the water in the ABS material. The exhaust in the granulation process is the main reason for the drying of the material. ABS material itself has a certain degree of water absorption, but this moisture can be removed by hot air drying. If the regenerated particles are not properly exhausted during the granulation process, it is likely that the water remaining inside the particles will remain.
It takes a long time for the moisture to dry. If the ordinary drying procedure is adopted, the drying material will not dry naturally. To solve this problem, we still need to start with melt extrusion granulation and improve the exhaust conditions during the melt extrusion process to avoid residual moisture inside the particles.
Foaming often occurs in the granulation of light-colored flame-retardant ABS. How to deal with the gray color?
This situation often occurs when the temperature of the melt extrusion equipment is not well controlled. Common flame-retardant ABS, its flame-retardant ingredients have poor heat resistance. In the secondary recovery, improper temperature control can easily decompose and cause foaming and discoloration. This situation is generally solved by adding a certain heat stabilizer. Two common types of additives are stearate and hydrotalcite.
What is the reason for the delamination after ABS granulation and toughening agent?
For the toughening of ABS, not all common toughening agents on the market can be used. For example, SBS, although its structure has the same parts as ABS, the compatibility of 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.
Is the alloy often heard of PC/ABS alloy?
Alloy material refers to a mixture formed by mixing two different polymers. In addition to the unique properties of the two materials, this mixture also has some new characteristics that the two do not have.
Because of this advantage, polymer alloys are a large group of materials in the plastics industry. PC/ABS alloy is just a specific material in this group. However, because PC/ABS alloy is widely used in the electrical industry, it is customary to use alloy to refer to PC/ABS alloy. Strictly speaking, PC/ABS alloy is an alloy, but the alloy is not just a PC/ABS alloy.
What is high-gloss ABS? What problems should be paid attention to when recycling?
High-gloss ABS is essentially the introduction of MMA (methacrylate) into the ABS resin. Because the gloss of MMA is much better than that of ABS itself, and its surface hardness is also higher than that of ABS. Particularly suitable for thin-walled large parts such as flat-panel TV panels, HD TV panels and bases. At present, the quality of domestic high-gloss ABS varies, and you need to pay attention to the toughness, gloss and surface hardness of the material when recycling. Generally speaking, materials with high fluidity, good toughness and high surface hardness have higher recycling value.
Someone on the market is selling ABS/PET materials. Can these two materials be mixed with each other? How to sort?
The basic principle of ABS/PET on the market is to add a certain proportion of PET to the ABS material and adjust the affinity between the two by adding a compatibilizer. This is a material that the modification company deliberately develops in order to obtain materials with new physical and chemical properties.
It is not suitable to do this kind of work when ABS is recycled. Moreover, the common equipment in the recycling process is a single-screw extruder, and the mixing capacity of the equipment is far inferior to the twin-screw extruder used in the modification industry. In the ABS recycling process, it is better to separate the PET material from the ABS material.
What is ABS bathtub material? How should it be recycled?
ABS bathtub material is actually a co-extruded material of ABS and PMMA. Because PMMA has higher surface gloss and indicated hardness, in the process of producing the bathtub, the manufacturer consciously co-extrudes a layer of PMMA material on the surface of the ABS extruded profile.
Recycling this kind of material does not require sorting. Because PMMA and ABS materials have good compatibility characteristics, the crushed materials can be directly mixed and 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 be added according to the requirements of the product ranging from 4% to 10%.
