Patent Application
20240410086
The present invention related to recycled nylon 6.6 pellet production from tire grade nylon 6.6 yarn scraps. Said recycled nylon 6.6 pellet is used in tire grade nylon 6.6 yarn production in different ratio with virgin nylon 6.6 pellet. Aim of this study is to get the comparable physical, thermal, mechanical properties and production process with recycled nylon 6.6. tire grade yarn with respect to virgin one. The study also serves the global sustainability issues that will deeply explain in below.
Nylon is a polymer, composed of repetitive units of diamines and dicarboxylic acids that contains different numbers of carbon atoms. Polymerization reaction takes place in a batch or continuous process in accompany with pressure, vacuum and heat. Nylon 6.6 thermoplastic polymer is made from petrochemical monomers, combined to form a long chain through a condensation polymerisation reaction.
Petroleum based polymers have been used since a long time due to its handiness, durability, flexibility, and less reactivity towards the water and other chemical. In the recent year, with the rise of global environment and sustainability issues, mankind begin to realize that word have limited petrochemical sources. This will endanger the balance between nature of the environment and development of science. Therefore, how to respect both of the environment and human development is became a challenging issue for the recent studies.
Nylon is not biodegradable, and will persist in the environment indefinitely. The two of the largest sources of microplastic pollution in the ocean are nylon fishing nets and synthetic textile fibers. This means that the impact of nylon on the aquatic environment is significant. On the other hand, the persistent nature of nylon means that it is infinitely recyclable and we could cease new nylon production now and still meet our desire for nylon if we recycled all of the nylon material currently in existence. Thus, it is need to increase the accessibility of nylon recycling schemes to the average consumer.
The present invention consists of two main processes and products as indicated below.
Pellet mixture that is consist of certain proportion of virgin and recycled nylon 6.6 pellets are go through the solid state polymerization process in a certain conditioning temperature to get the desired relative viscosity level for the spinning process. Virgin to recycle pellet level of 10:90 to 90:10, preferably production performed in range of 80:20 to 50:50 to get the comparable yield, process performance, productivity, sustainability of the production and product and also yarn properties. Both of the flake type has maximum 0.5% moisture level.
Addition to that, chopped nylon 6.6 yarn scraps finish oil level is between 0.7-1.0%. Before the recycled nylon 6.6 pellet production, there is no washing unit for scraps to get rid of the oil. Finish oil is removed from the scrap polymer in the vacuum zone of the extruder during the recycled nylon 6.6 pellet production steps that was detailed explained in
The present disclosure can be more understood by reading the following detailed description of the drawings as follows;
The invention relates to a tire grade nylon 6.6 mono- and/or multi filament yarn comprising at least 10% recycled nylon 6.6, preferably 20% recycled nylon 6.6 wherein the said nylon 6.6 mono or multi filament yarn has at least 8.0 gpd tenacity according to ASTM-D 885.
ASTM-D 885 is a standard test methods for tire cords, tire cord fabrics, and industrial filament yarns made from man-made organic-base fibers.
The tire grade nylon 6.6 mono- and/or multi filament yarn has at least 1.25 gpd 4% SASE according to ASTM-D 885.
A manufacturing method of a tire grade nylon 6.6 mono- and/or multi filament yarn comprises the steps of:
At the beginning of the process, tire grade oiled and/or non-oiled drawn and/or undrawn nylon 6.6 fiber scraps including filament yarn is cut ranges from 3 cm to 5 cm to get nylon 6.6 chopped fibers. Chopped fibers feed to extruder to get the molten polymer from the scrap yarns. Molten polymer shaped to molten fiber in a certain diameter and cool in a water bath. After cooling of the fiber polymer, they cut in a certain size that called strand pelletizing system in the literature.
Vacuum is active during the tire grade recycled pellet production to remove the finish oil in the polymer matrix coming from the scrap oiled yarn production process. It is very critical process for the production since the high finish oil level caused in low production yields and high break levels in spinning. Main aim is to minimize the finish oil level in the recycled pellet.
Since the tire grade recycled pellet and virgin pellet mixed during the production, homogeneous mixing is another critical parameter in the preparation phase of the solid state polymerization. Pellet size of the two pellet grade need to be as much as close each other to prevent separation in the silos. So that, granulometry of the tire grade recycled pellet were improved for the tire grade recycled yarn production.
Tire grade recycled amount in the yarn depends on the customer expectations and minimum specification requirements. However according to “Global Recycling Certification” system, minimum requirement of the recycled amount is 20% in the end product. So that according to this regulation, studies were focused to 20% recycled material in the tire grade yarn. Recycled pellet and virgin pellet was mixed and fed to silo for conditioning. Solid state polymerization was adjusted according to new mixtured raw material to get the same RV level at the end of the conditioner exit.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021/015509 | Oct 2021 | TR | national |
This application is a national stage entry of International Application No. PCT/TR2021/051018, filed on Oct. 6, 2021, which is based upon and claims foreign priority to Turkey Patent Application No. 2021/015509, filed on Oct. 5, 2021, the entire contents of which are incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/TR2021/051018 | 10/6/2021 | WO |
