POLYAMIDE 6 COMPOSITION AND AN ARTICLE PREPARED THEREFROM

Abstract

The present invention relates to a composition for injection molding, comprising Polyamide 6; and an inorganic nucleation agent. 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.

Claims

1. A composition for injection molding, comprising Polyamide 6 (PA 6), preferably in a content of greater than 90% by weight on the basis of the total weight of the composition; and an inorganic nucleation agent, preferably Y.sub.2O.sub.3, preferably in a content of 0.3-1 phr (parts per hundred parts of resin).

2. The composition according to claim 1, further comprising a mould release, preferably a wax, more preferably a polyolefin based wax, such as a polyethylene wax (e.g. LDPE-wax, HDPE-wax, or oxidized PE-wax), a polypropylene wax, or their mixture, preferably in a content of 1-2 phr.

3. The composition according to claim 1, further comprising a plasticizer, preferably polyethylene glycol (PEG) or polypropylene glycol, such as polyethylene glycol with a molecular weight from 400 to 8000, preferably in a content of 2-6 phr.

4. The composition according to claim 1, further comprising a primary antioxidant, preferably a hindered phenol or 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) tri-p-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] (Antioxidant1098), or their mixture, preferably in a content of 0-0.2 phr.

5. The composition according to claim 4, 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, wherein the Polyamide 6 is recycled Polyamide 6 from chemical recycling or biochemical recycling of waste nylon yarn.

7. 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.

8. 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

DETAILED DESCRIPTION

[0010] In one aspect, the present invention relates to a composition for injection molding, comprising Polyamide 6 (PA 6); and an inorganic nucleation agent.

[0011] The composition may comprise Polyamide 6 (PA 6) in a content of greater than 80%, greater than 90%, or greater than 95%, by weight on the basis of the total weight of the composition.

[0012] The composition may comprise an inorganic nucleation agent in a content of 0.3-1.5 phr (parts per hundred parts of resin), 0.3-1 phr, or 0.5-1 phr.

[0013] The term phr means parts per hundred parts of resin, i.e., parts per hundred parts of PA 6, calculated on the weight basis.

[0014] The nucleation agent may improve the injection molding smoothness of the composition.

[0015] The composition comprising the nucleation agent may provide an injection molded accessory, such as a buckle or zipper puller, with improved tensile strength as compared with a corresponding composition without the nucleation agent.

[0016] Preferably, the inorganic nucleation agent is Y.sub.2O.sub.3. Y.sub.2O.sub.3 does not turn yellow at a high temperature, such as about 260 degree C.

[0017] In one aspect, the composition further comprises a mould release.

[0018] In one aspect, the composition comprises a mould release in a content of 0.5-2.5 phr, or 1-2 phr.

[0019] Preferably, the mould release is a wax, for example a polyolefin based wax, such as a polyethylene wax (e.g. LDPE-wax, HDPE-wax, or oxidized PE-wax), a polypropylene wax, or their mixture.

[0020] The mould release may further improve the injection molding smoothness of the composition.

[0021] In one aspect, the composition further comprises a plasticizer.

[0022] The composition may comprise a plasticizer in a content of 1-10 phr, 2-8 phr, or 2-6 phr. Preferably, the plasticizer is polyethylene glycol (PEG) or polypropylene glycol, such as polyethylene glycol with a molecular weight from 400 to 8000.

[0023] The plasticizer may further improve the injection molding smoothness of the composition. In one aspect, the composition further comprises a primary antioxidant.

[0024] The composition may comprise a primary antioxidant in a content of 0-1 phr, 0-0.5 phr, or 0-0.2 phr.

[0025] Preferably, the primary antioxidant may be a hindered phenol or 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)tri-p-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](Antioxidant1098), or their mixture.

[0026] In one aspect, the composition further comprises a secondary antioxidant.

[0027] The composition may comprise a secondary antioxidant in a content of 0-1 phr, 0-0.5 phr, or 0-0.2 phr.

[0028] Preferably, the secondary antioxidant may be 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.

[0029] In one aspect, the Polyamide 6 is recycled Polyamide 6 from chemical recycling or biochemical recycling of waste nylon yarn.

[0030] For the chemical recycling process, it may mainly include the following steps:

[0031] Cleaning the pre-consumer PA6 scrap from waste fabric (such yarns with colorant);

[0032] Depolymerization of the scrap to small oligomer or monomer of PA6 (caprolactam) by different kinds of methods (see for example https://www.cetjournal.it/cet/23/100/122.pdf);

[0033] Separation of the small oligomer or monomer of PA6 and colorants, or other additives in the fabrics; and

[0034] Polymerization of the oligomer or monomer of the PA6 to PA6 molecules.

[0035] The unmodified chemically recycled PA6 polymer may have melt flow index of <20 g/10 min, under 230 degree C., 2.16 kg loading.

[0036] The composition may be obtained by mixing all the components.

[0037] In one aspect, the present invention relates to 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.

[0038] Preferably, the accessory does not comprise glass fiber, mineral fiber, or any other rigid fiber. Accordingly, the composition is suitable for mono-material recycling loop, in which the apparel made of waste yarn and the trims or accessories of the composition can be melted together to produce a new apparel product again, without dissasembling the trims or accessories first before melting.

[0039] In one aspect, the present invention relates to a method for preparing an article, such as an accessory, e.g. a button, a zipper puller, a buckle, a cord lock, a cord end, and a stopper, comprising injection molding of the composition.

[0040] Preferably, the method comprises injection molding of the composition with a cycle time within 30 seconds.

EXAMPLES

Materials

[0041] PA6 is chemically recycled Polyamide 6.

[0042] Virgin PA6 means those commercialized PA6 in the market, such as BASF Ultramid B3S, which usually contains not only molecule of PA6 itself, but also different kinds of additives, such as heat stabilizers, mold release, etc.

[0043] Unmodified chemically recycled PA6 means 100% PA6 molecule itself without adding any additives. It is purely 100% PA6 obtained by chemical recycling.

[0044] Anti-MS-oxidized wax is an oxidized PE wax.

[0045] LCP is a liquid crystal polymer.

[0046] Irganox 1010 by BASF is pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate.

[0047] Irgafos 168 by BASF is tris(2,4-di-tert.-butylphenyl)phosphite.

[0048] Irganox 1098 by BASF is a N,N-hexane-1,6-diylbis(3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide)).

Preparation of the Compositions

[0049] For each example, the composition was prepared by mixing all the components.

Test Procedure

[0050] The virgin PA6, the unmodified chemically recycled PA6, and the compositions are used in injection molding for producing buckles or zipper pullers.

[0051] Smoothness is observed in an injection molding process to see if mold sticking happens and if a molded part, such as a buckle or zipper puller, can be smoothly ejected.

[0052] The tensile strength is tested for a buckle or zipper puller under a pulling speed at 300 mm/min, at room temperature. The buckle or zipper puller is pulled until it breaks or separates.

[0053] The compositions and test results are shown in Table 1.

TABLE-US-00001 TABLE 1 PA6 Mould Strength Nucleation Heat Example % Release phr Enhance phr Agent phr Plasticizer phr Stabilizer Virgin PA6 Unmodified 100 chemically Recycled PA6 1 composition 99.8 NA-Y2O3 0.3 2 composition 99.5 NA-Y2O3 0.5 3 composition0 98.8 Anti-MS 1 NA-Y2O3 0.3 oxidized wax 4 composition 98 Anti-MS 1 NA-Y2O3 1 oxidized wax 5 composition 97.6 Anti-MS 1.5 NA-Y2O3 1 oxidized wax 6 composition 97.6 Anti-MS 2 NA-Y2O3 1 Irganox oxidized 1010 wax 7 composition 95.3 Anti-MS 1.5 LCP 2 NA-Y2O3 1 Irganox oxidized 1098 wax 8 composition 91.3 Anti-MS 1.5 NA-Y2O3 1 PEG8000 2% Irganox oxidized 1098 wax 9 composition 91.3 Anti-MS 1.5 NA-Y2O3 1 PEG8000 6 Irganox oxidized 1098 wax Tensile Tensile Strength in Strength in Tensile Buckle Tensile Zipper Puller Strength Injection (Industrial Strength (Industrial Increment Heat Molding Standard > Increment Standard > in zipper Example phr Stabilizer phr Smoothness 50 kg) in Buckle 12 g) puller Smooth 102.2 20.1 Serious 88.6 9.2 Mold Sticking 1 Slightly 120.6 36.1% 14.4 56.5% Mold Sticking 2 Slightly 120.41 35.9% 15.1 64.1% Mold Sticking 3 Smooth 97.3 9.8% 15.5 68.5% 4 Smooth 110 24.2% 22.3 142.4% 5 Smooth 102.7 15.9% 15.8 71.7% 6 0.2 Irgafos 0.2 Smooth 105.4 19.0% 15.2 65.2% 168 7 0.2 Smooth 95.8 8.1% 13.0 41.3% 8 0.2 Very 97.8 10.4% 15.1 64.1% Smooth 9 0.2 Very 83.5 5.8% 16.0 73.9% Smooth

[0054] The unmodified chemically recycled PA6 had a serious mold sticking problem in injection molding. The industrial standard is >50 kg for tensile strength in buckles, and >12 g for tensile strength in zipper pullers. The zipper puller made of the unmodified chemically recycled PA6 did not meet the industrial standard for tensile strength.

[0055] For examples 1-9, Y.sub.2O.sub.3 did not turn yellow at a high temperature, such as about 260 degree C.

[0056] With the nucleation agent, Examples 1 and 2 were only slightly mold sticking, and exhibited significantly improved tensile strength in both buckles and zipper pullers, as compared with the unmodified chemically recycled PA6.

[0057] Examples 3-7 further comprised an anti-ms-oxidized wax, and were smooth in injection molding, which was advantageous over Examples 1 and 2.

[0058] Examples 8 and 9 further comprising PEG8000 exhibited further improved injection molding smoothness over Examples 3-7.

[0059] All Examples 1-9 met the industrial standard for tensile strength in buckles and zipper pullers.

[0060] In Example 7, LCP (liquid crystal polymer) was incorporated into the composition to make the composition whiter.

[0061] Although the present invention is described with reference to the preferred embodiments, it is understood that various modifications are possible within the spirit or scope of the present invention.