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EP-4737511-A1 - A POLYAMIDE 6 COMPOSITION AND AN ARTICLE PREPARED THEREFROM

EP4737511A1EP 4737511 A1EP4737511 A1EP 4737511A1EP-4737511-A1

Abstract

The present invention relates to a Polyamide 6 composition and an article prepared therefrom. The present invention relates to a composition for injection molding, comprising Polyamide 6 of a yellow color; and a whitener. The present invention also provides an injection molded accessory, such as a button, a zipper puller, a buckle, a cord lock, a cord end, and a stopper, comprising the composition. The present invention also provides a method for preparing an article, such as an accessory, comprising injection molding of the composition.

Inventors

  • LEUNG, Hing Lun
  • LEUNG, Pui Kwan
  • LAU, KAM MING
  • FUNG, Kai Kwun

Assignees

  • Duraflex Hong Kong Limited

Dates

Publication Date
20260506
Application Date
20241127

Claims (11)

  1. A composition for injection molding, comprising Polyamide 6 (PA 6) of a yellow color, preferably in a content of greater than 90% by weight on the basis of the total weight of the composition, and a whitener, preferably polybutylene terephthalate, preferably in a content of 2-4 phr (parts per hundred parts of resin).
  2. The composition according to claim 1, further comprising a nucleation agent, preferably 2, 2'- methylene-bis (4,6-di-tert-butyl-phenyl) phosphate sodium, Aluminium hydroxybis[2,2'-methylen-bis(4,6-di-tert-butylphenyl)phosphate], or 1,3:2,4-Di-p-methylbenyliedene sorbitol, preferably in a content of 0.3-1.2 phr.
  3. The composition according to claim 1, further comprising a mold release, preferably polydimethylsiloxane, PE-WAX, Nylon-WAX, PET, Silicone oil, or PEG 1000 to PEG 8000, preferably in a content of 2-3 phr.
  4. The composition according to claim 1, further comprising a primary antioxidant, preferably a hindered phenol or a secondary aromatic amine, such as pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate, octadecyl-3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate], 3,3',3',5,5',5'-hexa-tert-butyl-a,a',a'-(mesitylene-2,4,6-triyl)trip-cresol, calcium-bis (((3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)methyl)-ethylphosphonate), bis (oxyethylene) bis-(3-(5-tert-butyl-4-hydroxy-m-tolyl)-propionate), 3,5-bis (1,1-dimethyl-ethyl)-4-hydroxy-C7-C9 branched alkyl esters, N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanamide], or their mixture, preferably in a content of 0-0.2 phr.
  5. The composition according to claim 1, further comprising a secondary antioxidant, preferably a phosphorus compound, such as tris(2,4-ditert-butylphenyl)phosphite, Bis(2.4-di-t-butylphenyl) Pentaerythritol Diphosphite, Tris(dipropyleneglycol) phosphite, Calcium bis[monoethyl(3,5-di-tert-butyl-4-hydroxylbenzyl)phosphonate], or their mixture, preferably in a content of 0-0.2 phr.
  6. The composition according to claim 1, further comprising a dispersing agent, preferably sodium stearate, sodium lauryl sulfate, ethoxylated alcohols, or PPG 1000 to PPG 4000, preferably in a content of 0.2-0.8 phr.
  7. The composition according to claim 1, further comprising a primary anti-UV agent, preferably 2,2'-Methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, preferably in a content of 0-0.2 phr.
  8. The composition according to claim 1, further comprising a secondary anti-UV agent, preferably N,N',N",N‴-tetrakis(4,6-bis(butyl-(N-methyl-2,2,6,6-tetramethylpiperidin-4-yl)amino)triazin-2-yl)-4,7-diazadecane-1,10-diamine, preferably in a content of 0-0.2 phr.
  9. The composition according to claim 1, wherein the Polyamide 6 is recycled Polyamide 6 from mechanical recycling of a waste fishing net.
  10. An injection molded accessory selected from the group consisting of a button, a zipper puller, a buckle, a cord lock, a cord end, and a stopper, preferably for a backpack or apparel, comprising the composition according to claim 1, preferably without glass fiber, mineral fiber, or any other rigid fiber.
  11. A method for preparing an article, such as an accessory selected from the group consisting of a button, a zipper puller, a buckle, a cord lock, a cord end, and a stopper, comprising injection molding of the composition according to claim 1, preferably with a cycle time within 30 seconds.

Description

FIELD OF THE INVENTION The present invention relates to a composition for injection molding comprising Polyamide 6, an injection molded accessory comprising the composition, and a method for preparing an article from the composition. BACKGROUND OF THE INVENTION Mechanically recycled pellets (RPA6) from Waste nylon fishing net are usually in high yellowness which is not good for producing colorful injection molded products. RPA6 directly from mechanically recycling waste fishing net is not suitable for injection molding due to a low tensile strength. Patent US20240117146A1 disclosed a recycled nylon from waste fishing net modified by carbon fiber which is black in color thus not suitable for producing colorful apparel or backpack accessories such as zipper pullers, or buckles. Other patents related to waste fishing net usually disclose technology to extract useful small molecular chemicals from waste fishing net as a way of recycling. For example, WO2024105472A2 disclosed a recovery of epsilon-caprolactam from nylon 6 comprising fishing nets. There is a need for a Polyamide 6 composition with a low delta b value suitable for injection molding to produce trims or accessories for colorful apparel products. There is also a need to use recycled Polyamide 6 (RPA6) from mechanical recycling of a waste fishing net to produce apparel trims or accessories so that all the components of the apparel are made of recycled Polyamide 6. Then the whole used apparel can be melted directly to produce a new apparel product again, without dissasembling the trims or accessories first before melting, to achieve better sustainability (mono-material concept). The possible apparel accessories include a button, a zipper puller, a buckle, a cord lock, a cord end, a stopper, etc. SUMMARY An objective of the invention is to provide a Polyamide 6 composition with a low yellowness. The yellowness can be evaluated with Hunter L, a, b or CIE 1976 L*a*b* (CIELAB) on a composition or an injection molded part. Color Delta b values can be used for evaluation of yellowness. A further objective of the invention is to provide a Polyamide 6 composition suitable for injection molding. A further objective of the invention is to provide an injection molded accessory selected from the group consisting of a button, a zipper puller, a buckle, a cord lock, a cord end, and a stopper, such as for a backpack or apparel, comprising PA6, without glass fiber, mineral fiber, or any other rigid fiber. It is desired that the accessory has an acceptable or improved tensile strength. The present disclosure provides a composition for injection molding, comprising Polyamide 6 (PA 6) of a yellow color, preferably in a content of greater than 90% by weight on the basis of the total weight of the composition, and a whitener, preferably polybutylene terephthalate (CAS No. 24968-12-5), preferably in a content of 2-4 phr (parts per hundred parts of resin). The present disclosure provides an injection molded accessory, such as a button, a zipper puller, a buckle, a cord lock, a cord end, and a stopper, preferably for a backpack or apparel, comprising the composition of the disclosure, preferably without glass fiber, mineral fiber, or any other rigid fiber. The present disclosure also provides a method for preparing an article, such as an accessory, comprising injection molding of the composition of the disclosure. The composition has a low yellowness. The composition is suitable for injection molding. It is not necessary to add glass fibers, mineral fibers, or any other rigid fibers in the composition for injection molding. Accordingly, the composition is suitable for mono-material recycling loop, in which the whole used apparel can be melted directly to produce a new apparel product again, without dissasembling the trims or accessories first before melting. The trims or accessories made of the composition have acceptable or improved tensile strength. DETAILED DESCRIPTION In one aspect, the present invention relates to a composition for injection molding, comprising Polyamide 6 (PA 6) of a yellow color, anda whitener. The composition may comprise Polyamide 6 (PA 6) in a content of greater than 90% by weight on the basis of the total weight of the composition. The composition may comprise a whitener in a content of 2-4 phr (parts per hundred parts of resin), 2-3.5 phr, or 3.5-4 phr. The term "phr" means parts per hundred parts of resin, i.e., parts per hundred parts of PA 6, calculated on the weight basis. Preferably, the whitener is polybutylene terephthalate (CAS No. 24968-12-5). Without being bound to any theories, it is believed that polybutylene terephthalate can create a second independent phase in the PA6 phase to block certain yellow light reflection. Polybutylene terephthalate can withstand the high temperature, such as 260-270 °C, in the process of injection molding, without causing yellowing. The whitener may reduce the yellowness. In one aspect, the composition fur