Method for recycling high-density polyethylene (HDPE) material by thermofusion and recycled HDPE products

Abstract

The present invention relates to a process for recycling waste high density polyethylene (HDPE) materials, which is carried out by thermofusion. Through this recycling process, products having particular qualities are obtained, and laminated products or products in the form of a molded block may be obtained. Said products, in addition to representing a benefit for the environment, exhibit particularities that make them different from virgin raw material products and recycled products, representing a surprising and unexpected technical advantage over those currently available.

Claims

1. A process for recycling high density polyethylene (HDPE) materials by thermofusion, comprising the steps of: crushing waste HDPE containers to form a crushed material; storing the crushed material in maxi sacks; pouring the crushed material into a wash container; washing the crushed material with a biodegradable degreaser; rinsing the crushed material with pure water; storing the rinsed, crushed material in maxi sacks to dry; pouring the rinsed and dry, crushed material into a thermofusion furnace; boiling, in a thermofusion furnace, the crushed material under specific conditions; removing the thermo-fused product from the thermofusion furnace; pressing the thermo-fused material; and extracting a molded product.

2. The process for recycling high density polyethylene (HDPE) materials, according to claim 1, wherein crushing includes placing the waste HDPE containers in a chipping machine.

3. The process for recycling high density polyethylene (HDPE) materials, according to claim 2, wherein the materials are crushed until reaching an approximate dimension from 1×1 cm to 10×10 cm.

4. The process for recycling high density polyethylene (HDPE) materials, according to claim 1, wherein the biodegradable degreaser has a neutral and washing time lasts from 10 to 14 minutes.

5. The process for recycling high density polyethylene (HDPE) materials, according to claim 1, wherein the rinsing step lasts 1 to 3 minutes.

6. The process for recycling high density polyethylene (HDPE) materials, according to claim 1, wherein the thermofusion furnace chamber must reach a temperature between 150° C. and 158° C. when pouring the crushed material.

7. The process for recycling high density polyethylene (HDPE) materials, according to claim 1, wherein the crushed material is poured into the thermofusion furnace, and after one minute, the temperature of the thermofusion furnace is raised to 170° C., during the following seven minutes, said temperature fluctuates between 170° C. and 180° C. producing a the laminated product.

8. The process for recycling high density polyethylene (HDPE) materials, according to claim 1, wherein pouring includes pouring the crushed material in three equal parts at separate times.

9. The process for recycling high density polyethylene (HDPE) materials, according to claim 8, wherein the first part stays in the furnace for 8 minutes, the second part is poured in the same thermofusion furnace containing the first part and is thermo-fused for 4 minutes, and, then, the third part is poured, which is left to thermo-fuse for 3 minutes.

10. The process for recycling high density polyethylene (HDPE) materials, according to claim 1, wherein the pressing of the thermo-fused product is carried out in a hydraulic press.

11. The process for recycling high density polyethylene (HDPE) materials, according to claim 10, wherein the thermo-fused product, after leaving the furnace, does not take more than 10 seconds to be moved to the hydraulic press.

12. The process for recycling high density polyethylene (HDPE) materials, according to claim 10, wherein the thermo-fused product is pressed for 5 seconds.

13. The process for recycling high density polyethylene (HDPE) materials, according to claim 12, wherein the thermo-fused product is submerged in cold water, at a temperature close to 5° C., for a period between 3 and 5 minutes.

14. The process for recycling high density polyethylene (HDPE) materials, according to claim 10, wherein the thermo-fused product is pressed for 60 seconds.

15. The process for recycling high density polyethylene (HDPE) materials, according to claim 14, wherein the thermo-fused product is submerged in cold water, at a temperature close to 5° C., for a period between 5 and 10 minutes.

16. The process for recycling high density polyethylene (HDPE) materials, according to claim 1, wherein the waste HDPE materials may be containers, sheets or meshes.

17. A planchette-shaped laminated product that is made from a waste HDPE material made following the thermofusion recycling process of claim 1, the product having an upper surface and an opposite bottom surface.

18. A planchette-shaped laminated product, according to claim 17, wherein both surfaces are smooth.

19. A planchette-shaped laminated product, according to claim 17, wherein at least one of its surfaces is textured.

20. A recycled HDPE product, made following the thermofusion recycling process of claim 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) For a better understanding of the present invention, the meaning of the following expressions must be clear:

(2) Thermofusion: corresponds to a molecular fusion, by high temperature, turning the fused parts into a single piece.

(3) Container: objects or utensils that have a cavity that allows introducing liquids, solid elements or even gases, according to their characteristics. Within what can be understood as container are very diverse objects, of different shapes and sizes, and created with all types of materials; although for the present case, only those formed by a plastic material are targeted.

(4) Maxi-sack: a flexible container used for storage and/or packaging of various products or materials; in the case of the present invention, crushed HDPE is stored. Its size is configured according to needs, but can range from 500 to 2,000 kilograms.

(5) Laminated product: a product having flat surfaces and specific length, width and thickness, including two opposite surfaces.

(6) The present invention relates to a process for recycling high density polyethylene (HDPE) materials by means of thermofusion, by means of which products made of recycled HDPE can be obtained, which have their own characteristics that are not available in the prior art, such as, for example, planchette-shaped laminated products or products in the form of blocks with different regular or irregular surfaces.

(7) Known techniques for recycling HDPE materials have the extrusion of the material as a central element, which makes the type of product that may be formed from known recycling processes to be limited. In fact, the products manufactured from recycled HDPE material that are currently available are only confined to pellets for second applications and containers for detergents, motor oils and garbage. In the present invention, products manufactured directly from a process of recycling HDPE by means of thermofusion are described.

(8) The recycled HDPE products of the present invention have characteristics that are not found in other HDPE materials manufactured by another process. Thus, the products of the present invention have: Sustainability: allows the use of recycled material in applications where virgin material could have been used, thus satisfying needs without exhausting the available natural resources. Durability: duration of the product can be up to 600 years. Texturable: at least one of the surfaces of the product can have some degree of texture. Versatility: it can be used in interior and exterior spaces. Waterproof: given its polymeric qualities, it is not affected by water, it is impermeable. Temperature: it resists high thermal oscillations in the environment. Atmospheric changes: its structure or form is not altered due to atmospheric changes Shocks: its high mechanical resistance helps it resist normal shocks. Antibacterial: its inert surface does not generate the proliferation of bacteria. Ease of cleaning: its chemical and mechanical resistance allows the ease of surface cleaning. Current insulator: because it is a very bad current conduction material, it serves as a current insulator It does not lose color: it does not suffer variations in color or texture. Resistance to alcohols, ketones, greases and oils: due to its chemical resistance quality. Non-toxic.

(9) After repeated and successive tests, a thermofusion process has been developed for recycling waste HDPE materials. Technically, thermofusion is a process by means of which molecular fusion of at least two pieces or products is achieved, becoming one single piece. The thermofusion process is developed under controlled temperature and pressure conditions, while the duration of the process will depend on the type of product that is produced.

(10) In the case of the present invention, the complete process of recycling HDPE materials will be largely conditioned by the relevance of thermofusion.

(11) Logically, the recycling process begins with the collection of waste materials; once the HDPE material is collected, the development of the process of the present invention is technically begun, which comprises, in general terms, the following steps: CUTTING: The required quantity of HDPE bottles are placed in a chipping machine to achieve 1×1 cm and maximum 10×10 cm cuts, which are then stored in maxi-sacks, which may hold up to 1 ton. WASHING, RINSING AND DRYING: The next step is washing, where the proportion is 25% biodegradable degreaser per 20 liters of water. This process should last between 10 and 14 minutes. Its technical specifications are directly related to the resting phase, which allows chemistry to act directly on the plastic until it completely clears dirt. After rinsing with pure water, for a period between 1 and 3 minutes, the plastic goes to an industrial filter, which works as a dryer, with a motor that rotates at a speed equal to 80 Km/h, for a period between 1 and 3 minutes. This is when the chip is ready to be stored in another maxi-sack to move to the Boiling step. BOILING: The amount of material to be boiled will depend on the object to be obtained. That range of variation will be between the same amount required to achieve the object, pouring into the mold in one go (laminated products); or one third of the estimated amount needed for a particular object, in one go, in three steps (block products). The furnace, if a gas-burned furnace, must remain on one hour before introducing the material; if the furnace is electric, it must be turned on half an hour before introducing the material, reaching in both cases a temperature between 150° C. and 158° C. For laminated products, the material is poured into the mold in one go, and after one minute, the furnace temperature is raised to 170° C.; during the next seven minutes, this temperature will range between 170° C. and 180° C. Then, the product is removed from the furnace. For block products, on the other hand, the material is poured into the mold in three equal parts, each one at its own time; this as a way to ensure the stability of the material. The first layer stays for 8 minutes, the second one is poured at 4 minutes, and the third one at 3 minutes, totaling a time of 15 minutes. The furnace temperatures corresponding to each of these time periods are also defined: after one minute, the furnace temperature is raised to 170° C.; in the second and third pouring (equivalent to two and three thirds of the material), the temperature will not be modified and will range between 170° C. and 180° C. At that point, the HDPE thermo-fused product, recycled, is removed from the furnace, to move to the next step: pressing. In parallel, both for the case of laminated products and block products, the furnace is left open for 10 seconds, where temperature drops to a range from 150° C. to 158° C., being able to start a new process. PRESSING: In 10 seconds, after being removed from the furnace, the product must be in the hydraulic press. For laminated products, pressing is carried out for 5 seconds, and products are hooked on the press “T's” and then submerged in water that has to be cold, at a temperature close to 5° C., for a period between 3 and 5 minutes. Then, the mold is opened and the laminated plate is removed. For block products, the product hooking mode changes; thus, while in laminated products hooking is carried out from the surface towards the bottom of the mold, in block products the mold faces are hooked, because the greater the volume, the more difficult to extract the product from the mold. Then the product is submerged in water at the same temperature, but for a period of 5 to 10 minutes, being ready to be unmolded.

(12) In practical terms, the process of the present invention can be presented sequentially by the following actions.

(13) Process for recycling high density polyethylene (HDPE) materials by means of thermofusion, which comprises the steps of: crushing waste HDPE materials; storing crushed material in maxi sacks; pouring the crushed material into a wash container; washing the crushed material with a biodegradable degreaser; rinsing the crushed material with pure water; storing clean crushed material in maxi sacks; pouring the clean and dry, crushed material into a thermofusion furnace; boiling, by thermofusion, the material under specific conditions; removing the thermo-fused product from the thermofusion furnace; pressing the thermo-fused material; and extracting the molded product.

(14) In the process for recycling high density polyethylene materials of the present invention, the waste HDPE materials may be containers, sheets or meshes, and during the crushing step, the waste HDPE materials are placed in a chipping machine, crushing until reaching approximate dimensions of 1×1 cm to 10×10 cm; after the material is crushed, it is transferred to maxi-sacks that may contain up to one ton of crushed material.

(15) In the process for recycling high density polyethylene materials of the present invention, in the step of washing the crushed material, the biodegradable degreaser used is neutral and washing time is extended from 10 to 14 minutes, the rinsing steps lasts between 1 and 3 minutes. The drying step is carried out by means of an industrial filter acting as a dryer, whose motor rotates at a speed equivalent to 80 km/h and lasts between 1 and 3 minutes.

(16) In the process for recycling high density polyethylene materials of the present invention, the amount of clean, dry, crushed material poured into the thermofusion furnace will depend on the type of product to be obtained. In the case of laminated products, the same required quantity of crushed material as the end product to be obtained is poured. In the case of block or specific products, one third of the total amount of crushed material required is poured for the end product to be obtained.

(17) In the process for recycling high density polyethylene materials of the present invention, if, in the boiling step, a thermofusion furnace using gas is used, said furnace must be turned on about an hour before the crushed material is poured. If an electric thermofusion furnace is used in the boiling step, said furnace must be turned on about half an hour before the crushed material is poured.

(18) Regardless of the type of furnace used, the thermofusion furnace chamber must reach a temperature between 150° C. and 158° C. when pouring the crushed material. To produce a laminated product, the crushed material is poured into the furnace mold in one go, and after one minute, the temperature of the furnace raises to 170° C., during the following seven minutes, said temperature ranges between 170° C. and 180° C.; finally, the laminated product is taken out of the furnace. When a block product is produced, the crushed material is poured, separately, into three equal parts of crushed material, each of said parts at a specific time, wherein, the first layer of material, equivalent to one third of the amount estimated by product, stays in the furnace for 8 minutes, the second layer is poured in the same mold that contains the first layer and is thermo-fused for 4 minutes, and then the third layer is poured, which is left to thermo-fuse for 3 minutes; the furnace temperatures corresponding to each of the time periods are handled such that, after one minute, the furnace temperature rises to 170° C.; in the second and third variation, equivalent to pouring two and three thirds of the material, the temperature is not modified and will range between 170° C. and 180° C.; finally, once the thermo-fused product is removed from the furnace, said furnace is left open for 10 seconds, the temperature decreasing to a range from 150° C. to 158° C., being, in this way, able to start a new process.

(19) In the process for recycling high density polyethylene materials of the present invention, the pressing of the thermo-fused product is carried out in a hydraulic press, taking care that the thermo-fused product, after leaving the furnace, does not take more than 10 seconds to be moved to the hydraulic press. In the case of the laminated thermo-fused product, it is pressed for 5 seconds, and after being pressed, it is hooked on the press “T's” and submerged in cold water, at a temperature close to 5° C., for a period between 3 and 5 minutes, the mold being finally opened and the laminated product being removed. On the other hand, in the case of the block thermo-fused product, it is pressed for 60 seconds, and after being pressed, it is hooked on the mold faces and submerged in cold water, at a temperature close to 5° C., for a period between 5 and 10 minutes, the mold being finally opened that the block product being removed.

(20) On the other hand, in the present invention, the final HDPE products obtained by the recycling process previously described are also protected. This includes all types of products that can be formed, such as: planchette-shaped laminated products of different dimensions, products for jacketing mine drillings, pipes of different diameter, ornamental and decorative products, insulating products for electrical conductors, and any another type of product that can be technically developed and produced.

(21) One of the important applications that can be obtained through the process of the invention is the production of a planchette-shaped laminated product, which will be comprised of HDPE recycled material, and will comprise an upper surface and an opposite bottom surface; wherein, both surfaces may be smooth, or at least one of the surfaces will be textured. The length and of said planchette-shaped laminated product will range between 5 cm and 2,000 cm, the square planchette being a preferred product, whose dimensions are 60 cm by 60 cm.

(22) The different products that can be produced through the process of the present invention, but, in particular, the planchette-shaped laminated product, may be of a single color, or may be multicolored, and may have veins of different colors.

(23) In the case of producing a product in the form of a block, it will be comprised of a HDPE recycled material and may have different regular and/or irregular surfaces.

(24) As previously mentioned, all recycled HDPE products, which are produced according to the process of the present invention, will have qualities that makes them different from other products of different materials or other products of the same virgin material, such as: durability, texturable, versatility, waterproof, resistant to temperature changes, resistant to atmospheric changes, high mechanical resistance, antibacterial, easy to clean, chemical resistance, electric current insulator and non-toxic. All these qualities give it a technical advantage over recycled products known in the prior art.

(25) The above list of products cannot be considered as limiting in the manufacture of products through the process of the present invention, all those products that can be manufactured according to the process of recycling HDPE by thermofusion should be included as part of the invention.