Most of the packaging films used these days are either polyethylene or polypropylene or co-extruded sheets of both these polymers.for recycling these polymer mixtures selective dissolution methods are employed.
Basically the process is outlined as below:
1.the mixed plastic sheets are collected,crushed into smaller area and washed with detergents to remove contaminants like dust,food scraps and other clinging particles.
2.The cleaned sheets are shredded completely into fine flakes.
3.flakes are separated into PE and PP by selective dissolution methods using a suitable solvent to dissolbe any one polymer ans so the other is separated out.
4.the separated polymers are reprocessed separately in extruders and the extrudates are pelletised and reused for various other applications.
POLYURETHANE FOAM RECYCLING
The process for the recycling of microcellular polyurethanes which comprises the steps of:
1.comminuting the microcellular polyurethanes
2.admixing a mixture which comprises the comminuted polyurethanes in an amount of from 0.1 to 40 percent by weight, based on the polyaddition mixture, with (a) polyisocyanates, (b) substances reactive toward isocyanates and containing active hydrogens, and optionally, (c) chain extenders and/or crosslinkers, catalysts, blowing agents and customary additives, to prepare a prepolymer.
3.reacting said prepolymer with water, and optionally, additional amounts of (c) to produce a recycled polyurethane.
Chemical processes such as hydrolysis, hydrogenation, pyrolysis and glycolysis are suitable for the recycling of polyurethanes. Furthermore, the polyurethanes can be dissolved in isocyanates and the resulting mixture can, after purification, be reused. Common to these processes is the fact that the polyurethanes can be reintroduced into their production process only at considerable expense and usually not without a loss of quality.
Further processes for recycling comprise the preparation of compact polyurethanes from comminuted elastomers ("flake bonding") or use as filler material in the preparation of new components.Introduction of comminuted polyurethanes into the polyol component for preparing polyisocyanate polyaddition products where air introduced with the polyurethanes caused considerable problems which became apparent in an undesired increase in the viscosity. This problem was solved by wetting the comminuted polyurethanes with volatile hydrocarbons. The addition of these substances may be disadvantageous for systems in which these materials are not used as blowing agents and is to be avoided. A loss in quality of the polyurethane which is prepared using recycled polyurethanes compared with the recycled elastomers can be avoided only with difficulty in the known processes, particularly in the case of microcellular polyurethane elastomers.
1.comminuting the microcellular polyurethanes
2.admixing a mixture which comprises the comminuted polyurethanes in an amount of from 0.1 to 40 percent by weight, based on the polyaddition mixture, with (a) polyisocyanates, (b) substances reactive toward isocyanates and containing active hydrogens, and optionally, (c) chain extenders and/or crosslinkers, catalysts, blowing agents and customary additives, to prepare a prepolymer.
3.reacting said prepolymer with water, and optionally, additional amounts of (c) to produce a recycled polyurethane.
Chemical processes such as hydrolysis, hydrogenation, pyrolysis and glycolysis are suitable for the recycling of polyurethanes. Furthermore, the polyurethanes can be dissolved in isocyanates and the resulting mixture can, after purification, be reused. Common to these processes is the fact that the polyurethanes can be reintroduced into their production process only at considerable expense and usually not without a loss of quality.
Further processes for recycling comprise the preparation of compact polyurethanes from comminuted elastomers ("flake bonding") or use as filler material in the preparation of new components.Introduction of comminuted polyurethanes into the polyol component for preparing polyisocyanate polyaddition products where air introduced with the polyurethanes caused considerable problems which became apparent in an undesired increase in the viscosity. This problem was solved by wetting the comminuted polyurethanes with volatile hydrocarbons. The addition of these substances may be disadvantageous for systems in which these materials are not used as blowing agents and is to be avoided. A loss in quality of the polyurethane which is prepared using recycled polyurethanes compared with the recycled elastomers can be avoided only with difficulty in the known processes, particularly in the case of microcellular polyurethane elastomers.
ABS RECYCLING
The process for recycling commingled plastics,more particularly relates to a process for shredding, separating and blending commingled poly(acrylonitrile-c-butadiene-c-styrene) (ABS) and polycarbonate ABS (PCABS) to produce recycled ABS/PCABS useful in the manufacture of products.
ABS is extensively used in the manufacture of inexpensive, durable products. The durability of ABS has made it a primary material in the manufacture of products such as, computer housings, televisions and computer monitor housings, automobile components, etc.
Unfortunately, however, ABS is somewhat expensive when supplied in its purest form. As such, the cost of manufacturing some products with ABS is prohibitively expensive despite the fact that the material characteristics of the ABS are well suited for the manufacture of the products.
Where the recycled goods are composed of a single plastic component (for example, plastic soda and milk containers), recycling is highly cost effective and leads to many useful products. However, the necessity of separating the assortment of plastic components prior to shredding and granulating makes recycling commingled plastic products highly time consuming and prohibitively expensive. Existing recycling techniques are, therefore, not appropriate where the recycled goods include many components composed of various plastics.
For example, where it is desired to recycle the plastic components of a computer housing (which is primarily composed of ABS, PCABS, and other plastics) to take advantage of the recycled ABS, the computer housing must first be separated into various components representing the many plastics used in the construction of the computer housing. This is highly time consuming, and makes recycling computer housings cost prohibitive. Such limitations are commonly found with ABS products one might consider appropriate for recycling.
The lack of an effective recycling process for those products already manufactured from ABS leaves previously used ABS products wasted once the useful life of the manufactured product is reached. Many materials have found a second life through recycling. However, a process for refining the used material must be developed before the material may find a second life in another product. Often, the second life of a product requires that the material be used in an environment where the aesthetic appearance of the material is not as important as when the material was used for its original purpose.
Unfortunately, no process is currently known for effectively and efficiently recycling ABS for subsequent use. The present process for recycling ABS in a manner permitting previously used ABS to obtain a second life. The present process employs shredding, separating and blending to recycle used ABS for subsequent use in other products, for example, substrates of decorative laminates.
SHREDDER
ABS is extensively used in the manufacture of inexpensive, durable products. The durability of ABS has made it a primary material in the manufacture of products such as, computer housings, televisions and computer monitor housings, automobile components, etc.
Unfortunately, however, ABS is somewhat expensive when supplied in its purest form. As such, the cost of manufacturing some products with ABS is prohibitively expensive despite the fact that the material characteristics of the ABS are well suited for the manufacture of the products.
Where the recycled goods are composed of a single plastic component (for example, plastic soda and milk containers), recycling is highly cost effective and leads to many useful products. However, the necessity of separating the assortment of plastic components prior to shredding and granulating makes recycling commingled plastic products highly time consuming and prohibitively expensive. Existing recycling techniques are, therefore, not appropriate where the recycled goods include many components composed of various plastics.
For example, where it is desired to recycle the plastic components of a computer housing (which is primarily composed of ABS, PCABS, and other plastics) to take advantage of the recycled ABS, the computer housing must first be separated into various components representing the many plastics used in the construction of the computer housing. This is highly time consuming, and makes recycling computer housings cost prohibitive. Such limitations are commonly found with ABS products one might consider appropriate for recycling.
The lack of an effective recycling process for those products already manufactured from ABS leaves previously used ABS products wasted once the useful life of the manufactured product is reached. Many materials have found a second life through recycling. However, a process for refining the used material must be developed before the material may find a second life in another product. Often, the second life of a product requires that the material be used in an environment where the aesthetic appearance of the material is not as important as when the material was used for its original purpose.
Unfortunately, no process is currently known for effectively and efficiently recycling ABS for subsequent use. The present process for recycling ABS in a manner permitting previously used ABS to obtain a second life. The present process employs shredding, separating and blending to recycle used ABS for subsequent use in other products, for example, substrates of decorative laminates.
SHREDDER
The process employs shredding, separation and blending of commingled plastics to produce recycled ABS and PCABS useful in the manufacture of new products. The present recycling process employs a series of steps to remove undesirable components. The removed undesirable components include, but are not limited to, metals, resins, foams, thermosets, rubbers, and foils, which, if included in the recycled product would prevent subsequent use of the recycled product. Specifically, any of these undesirable components would contaminate the recycled product and prevent further processing of the recycled product, for example, by extrusion.
Then further processes are
1.Shredded ABS blend is separated from metallic impurities by magnetic separator.
1.Shredded ABS blend is separated from metallic impurities by magnetic separator.
2.The flakes are then washed in a specific gravity tank to separate the blend based on their density.
3.Separated flakes are washed in a wash tank and air-dried.
4.ABS recovered from the process is re-processed in an extruder and re-used for secondary engineeering applications.
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