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KR-20260066106-A - Low-release polyoxymethylene composition

KR20260066106AKR 20260066106 AKR20260066106 AKR 20260066106AKR-20260066106-A

Abstract

A polyoxymethylene polymer composition comprising a formaldehyde stabilizer package is disclosed. In one embodiment, the formaldehyde stabilizer package comprises substituted hydantoin, which has been found to dramatically reduce formaldehyde emissions, either alone or in combination with other emission control agents. It has also been found that lower formaldehyde emissions occur when the polymer composition does not contain calcium stearate.

Inventors

  • 쿠르즈 클라우스
  • 옴 크리스티안

Assignees

  • 셀라니즈 인터내셔날 코포레이션

Dates

Publication Date
20260512
Application Date
20240905
Priority Date
20230908

Claims (20)

  1. Polyoxymethylene polymer; and A formaldehyde stabilizer package for reducing formaldehyde emission, wherein the formaldehyde stabilizer package comprises at least two emission control agents, and the emission control agents comprise a combination of an aliphatic carboxylic acid hydrazide and a substituted hydantoin. A polymer composition comprising, wherein the polymer composition does not contain calcium stearate and calcium 12-hydroxystearate.
  2. A polymer composition according to claim 1, wherein the polymer composition does not contain an alkaline earth metal salt of an aliphatic carboxylic acid.
  3. A polymer composition according to claim 1, wherein the aliphatic carboxylic acid hydrazide is present with respect to the substituted hydantoin in a weight ratio of about 1:20 to about 10:1, for example, about 1:8 to about 2:1.
  4. A polymer composition according to claim 1, wherein the substituted hydantoin comprises two hydrazinocarbonyl alkyl groups.
  5. A polymer composition according to claim 1, wherein the substituted hydantoin comprises 4-isopropyl-2,5-dioxomidazolidin-1,3-di(propionohydrazide).
  6. A polymer composition according to any one of claims 1 to 5, wherein the aliphatic carboxylic acid hydrazide comprises sebacic acid dihydrazide, dodecanedioic acid dihydrazide, or a mixture thereof.
  7. A polymer composition according to any one of claims 1 to 6, wherein the aliphatic carboxylic acid hydrazide is present in the polymer composition in an amount of less than about 0.15 weight%.
  8. A polymer composition according to any one of claims 1 to 7, wherein the polymer composition exhibits formaldehyde emission of less than about 20 ppm when tested according to the VDA-275 test at a molding temperature of 205°C with a thickness of 1 mm.
  9. A polymer composition according to any one of claims 1 to 8, wherein the polymer composition exhibits formaldehyde emissions of less than about 8 ppm, e.g., less than about 5 ppm, e.g., less than about 3 ppm, when tested according to the VDA-275 test at a molding temperature of 185°C with a thickness of 1 mm, and formaldehyde emissions of less than about 15 ppm, e.g., less than about 10 ppm, when tested according to the VDA-275 test at a molding temperature of 195°C with a thickness of 1 mm.
  10. A polymer composition according to any one of claims 1 to 9, wherein the polymer composition exhibits formaldehyde emission of less than about 300 μg/ m³ , e.g., less than about 250 μg/ m³ , e.g., less than about 200 μg/ m³ , e.g., less than about 150 μg/ m³ when tested according to a 10-liter bag test at a molding temperature of 195°C.
  11. A polymer composition according to any one of claims 1 to 10, wherein the polymer composition exhibits formaldehyde emission of less than about 10,000 μg/ m³ , e.g., less than about 5,000 μg/ m³ , e.g., less than about 1,000 μg/ m³ , e.g., less than about 750 μg/ m³ when tested according to a 10-liter bag test at a molding temperature of 205°C.
  12. A polymer composition according to any one of claims 1 to 11, wherein the substituted hydantoin is present in the polymer composition in an amount greater than about 0.01 weight%, for example, in an amount greater than about 0.03 weight%, for example, in an amount greater than about 0.07 weight%, for example, in an amount greater than about 0.08 weight%, and in an amount less than about 0.5 weight%.
  13. A polymer composition according to any one of claims 1 to 12, wherein the polyoxymethylene polymer has a melt flow rate of about 5 cm³ /10 min to about 15 cm³ /10 min when tested at 190°C and a load of 2.16 kg.
  14. A polymer composition according to any one of claims 1 to 13, wherein the polymer composition further comprises a nucleating agent in an amount of about 0.05 weight% to about 1 weight%.
  15. A polymer composition according to any one of claims 1 to 14, wherein the polymer composition further comprises an amount of about 0.05% to about 2 weight% of a phenolic antioxidant and an amount of about 0.05% to about 1.5 weight% of a lubricant.
  16. A polymer composition according to any one of claims 1 to 15, wherein the polymer composition further comprises a thermoplastic elastomer in an amount of about 5% to about 30% by weight.
  17. A polymer composition according to any one of claims 1 to 16, wherein the polymer composition further comprises reinforcing fibers in an amount of about 3 weight% to about 40 weight%.
  18. A polymer composition according to any one of claims 1 to 17, wherein the polymer composition further comprises a UV stabilizer.
  19. Polyoxymethylene polymer; A formaldehyde stabilizer package for reducing formaldehyde emissions, wherein the formaldehyde stabilizer package comprises a combination of an aliphatic carboxylic acid hydrazide and a substituted hydantoin, and the substituted hydantoin comprises two hydrazinocarbonyl alkyl groups; and Formaldehyde emission of less than approximately 20 ppm when tested according to the VDA-275 test at a molding temperature of 205°C with a thickness of 1 mm, and formaldehyde emission of less than approximately 1000 μg/ m³ when tested according to the 10-liter bag test at a molding temperature of 205°C. A polymer composition comprising
  20. In claim 19, the polymer composition is one in which the above polymer composition does not contain an alkaline earth metal salt of an aliphatic carboxylic acid.

Description

Low-release polyoxymethylene composition The present invention relates to a low emission polyoxymethylene composition. Polyacetal polymers, commonly referred to as polyoxymethylene, have been established as highly useful engineering materials for various applications. For instance, polyoxymethylene polymers are widely used to construct molded parts, such as components for use in the automotive and electrical industries. For example, polyoxymethylene polymers possess excellent mechanical properties, fatigue resistance, wear resistance, chemical resistance, and moldability. While polyacetal resins possess many useful properties, these polymers tend to decompose when heated and are inherently unstable in oxidizing atmospheres or acidic or alkaline environments. In particular, polyacetal resins tend to release formaldehyde during processing and after the polymer is molded into parts. Formaldehyde is not only a contaminant but can also adversely affect metal parts that may be placed in combination with the polymer. For example, formaldehyde readily oxidizes to formic acid, which can cause corrosion or discoloration of metals. In light of the above, those skilled in the art have attempted to combine polyacetal polymers with various compounds to reduce formaldehyde emissions. For example, in the past, polyacetal polymers have been combined with melamine to achieve lower formaldehyde emission performance. Additionally, various other chemical compounds have been proposed to reduce formaldehyde emissions. Various chemical compounds used in the past have successfully reduced formaldehyde emissions from products made of polyoxymethylene polymers, but further improvements in formaldehyde emissions are needed. For example, stricter government regulations continue to require additional improvements in reducing formaldehyde emissions. From the above perspective, there is a need for an improved formaldehyde stabilizer package capable of further reducing formaldehyde emissions. Generally, the present disclosure relates to polymer compositions comprising primarily polyacetal resins and molded products made from said compositions. The polymer compositions of the present disclosure are manufactured to exhibit particularly ultra-low formaldehyde emissions. For example, a polyoxymethylene polymer composition manufactured according to the present disclosure may exhibit formaldehyde emissions of less than about 2 ppm, e.g., less than about 1 ppm, when tested according to VDA test 275. The VDA 275 test (German Automotive Industry Advisory No. 275) was documented by Kraftfahrwesen e. V. in July 1994. Unless otherwise indicated, said test is performed on a plaque (40 mm x 100 mm) having a thickness of 1 mm, and formaldehyde emissions are tested 24 hours after extraction. In one embodiment, for example, the polymer composition of the present disclosure comprises a polyoxymethylene polymer together with a formaldehyde stabilizer package for reducing formaldehyde emissions. In one embodiment, the formaldehyde stabilizer package may include at least one emission control agent. In particular, a specific substituted hydantoin has been found to be highly effective in reducing formaldehyde emissions. The substituted hydantoin may be used in combination with other hydrazides and/or other emission control agents. Molded articles manufactured according to the present disclosure may also exhibit very stable color quality, which makes the polymer composition highly suitable for producing interior automotive trim pieces, etc. In one embodiment, for example, the present disclosure relates to a polyoxymethylene polymer combined with a formaldehyde stabilizer package comprising a substituted hydantoin together with one or more aliphatic carboxylic acid hydrazides. The weight ratio between the aliphatic carboxylic acid hydrazides and the substituted hydantoin may be about 1:20 to about 10:1, e.g., about 1:8 to about 2:1, e.g., about 1:4 to about 1.25:1. The substituted hydantoin may be present in the polymer composition in an amount of less than about 3% by weight, for example, less than about 2% by weight, for example, less than about 1% by weight, for example, less than about 0.8% by weight, for example, less than about 0.5% by weight, and generally in an amount greater than about 0.01% by weight, for example, greater than about 0.03% by weight, for example, greater than about 0.05% by weight, for example, greater than about 0.09% by weight, for example, greater than about 0.1% by weight, for example, greater than about 0.12% by weight, for example, greater than about 0.15% by weight, for example, greater than about 0.17% by weight, for example, greater than about 0.2% by weight. The substituted hydantoin may contain two hydrazinocarbonyl alkyl groups. The substituted hydantoin may have a melting point of about 150°C or less, e.g., about 140°C or less, e.g., about 130°C or less, e.g., about 125°C or less, and generally may have a melting point exceed