Polyoxymethylene resin composition and molded article prepared therefrom

Abstract

One embodiment provides a polyoxymethylene resin composition comprising a polyoxymethylene resin, a dihydrazide compound, and a urea compound, wherein the weight ratio of the dihydrazide compound and the urea compound is 1:3 to 1:5.

Description

Polyoxymethylene resin composition and molded article prepared therefrom

[0001] The present disclosure relates to a polyoxymethylene resin composition and a molded article made therefrom.

[0002] Polyoxymethylene resin is widely used in various fields as an engineering resin with excellent physical properties, such as mechanical and electrical characteristics, and chemical properties, such as chemical resistance and heat resistance.

[0003] However, as the application range of polyoxymethylene resins expands, it is required that the polyoxymethylene resins possess more specialized properties.

[0004] Conventionally, when manufacturing molded products by injection molding polyoxymethylene resin, there was a problem in which the resin decomposed, forming deposits such as mold deposits on the surface of the mold cavity. In particular, when the polyoxymethylene resin contains additives to reduce formaldehyde emissions, the occurrence of such deposits increases further, which caused defects in molded products using polyoxymethylene resin.

[0005] The present disclosure provides a polyoxymethylene resin composition having a significantly low amount of deposits and a low amount of formaldehyde gas emission even when manufactured under harsh injection molding conditions, and a molded article manufactured using the same.

[0006] A polyoxymethylene resin composition according to one aspect comprises a polyoxymethylene resin, a dihydrazide compound, and a urea compound, wherein the weight ratio of the dihydrazide compound to the urea compound is 1:3 to 1:5.

[0007] The polyoxymethylene resin may be included in an amount of 95% to 99.8% by weight relative to 100% by weight of the polyoxymethylene resin composition.

[0008] The melting point of the above polyoxymethylene resin may be 160 ℃ to 180 ℃.

[0009] The dihydrazide compound may be included in an amount of 0.01% to 1% by weight relative to 100% by weight of the above polyoxymethylene resin composition.

[0010] The above dihydrazide compound may include adipic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, dodecanedioic dihydrazide, 1,12-dodecanedicarboxylic acid dihydrazide, or a combination thereof.

[0011] The urea compound may be included in an amount of 0.01% to 1% by weight relative to 100% by weight of the above polyoxymethylene resin composition.

[0012] The above urea compound may include ethylene urea, (2,5-dioxo-4-imidazolidinyl)urea, or a combination thereof.

[0013] The above polyoxymethylene resin composition may further include a metal salt phosphate-based compound.

[0014] The above metal salt phosphate-based compound may be an ester-based compound containing a metal salt comprising Mg, Ca, Zn, Ba, Fe, or a combination thereof.

[0015] The metal salt phosphate-based compound may be included in an amount of 0.01% to 1% by weight relative to 100% by weight of the above polyoxymethylene resin composition.

[0016] The above polyoxymethylene resin composition may further include a hindered phenolic antioxidant.

[0017] The hindered phenolic antioxidant may be included in an amount of 0.01% to 0.5% by weight relative to 100% by weight of the above polyoxymethylene resin composition.

[0018] A molded article according to another aspect is manufactured from the above polyoxymethylene resin composition.

[0019] The above molded product may have a formaldehyde gas emission of 2 mg / kg or less at 200 ℃ according to VDA-275 standards.

[0020]

[0021] The polyoxymethylene resin composition according to one embodiment and the molded article manufactured using the same have the advantage of significantly lower deposition and lower formaldehyde gas emission even when manufactured under harsh injection molding conditions.

[0022] Figure 1 is a photograph showing an injection molded product with a deposit amount of '1' (none).

[0023] Figure 2 is a photograph showing an injection molded product with a deposit amount of '10' (severe).

[0024] The advantages and features of the technology described below, and the methods for achieving them, will become clear by referring to the embodiments described in detail below. However, the forms of implementation are not limited to the embodiments disclosed below. Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning that is commonly understood by those skilled in the art. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0025] Throughout this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Furthermore, the singular form includes the plural form unless specifically stated otherwise in the text.

[0026]

[0027] A polyoxymethylene resin composition according to one embodiment comprises a polyoxymethylene resin, a dihydrazide compound, and a urea compound, wherein the weight ratio of the dihydrazide compound to the urea compound is 1:3 to 1:5.

[0028] A polyoxymethylene resin composition according to one embodiment includes a dihydrazide compound and a urea compound, which are additives for reducing formaldehyde, in an optimal weight ratio, thereby maintaining the formaldehyde gas emission control performance while preventing deposition or significantly improving the degree of deposition even under harsh injection molding conditions.

[0029]

[0030] Polyoxymethylene resin

[0031] Polyoxymethylene resin serves as the base resin of the resin composition, playing a role in securing the basic mechanical and chemical properties of the resin, and in particular, performs an important function in impact resistance.

[0032] Polyoxymethylene can be used without particular limitation as long as it is a standard polyoxymethylene commercially available.

[0033] Polyoxymethylene has oxymethylene -(OCH2) as a repeating unit n- It may be an oxymethylene homopolymer in which both ends are blocked by ester or ether groups, an oxymethylene copolymer in which oxyalkylene units having 2 to 8 carbon atoms are randomly inserted into a polymer main chain composed of oxymethylene monomer units, and both ends of the polymer are blocked by ester or ether groups, or a terpolymer.

[0034] For example, oxymethylene homopolymers and oxymethylene copolymers can be prepared by the following method. First, oxymethylene homopolymers can be prepared by introducing formaldehyde anhydride into an organic solvent containing a basic polymerization catalyst, such as, for example, an organic amine, an organic or inorganic tin compound, or a metal hydroxide, polymerizing the polymer, filtering the polymer, and then heating the ends in acetic anhydride in the presence of sodium acetate to acetylate them.

[0035] In addition, oxymethylene copolymers can be prepared by dissolving or suspending a cyclic oligomer of formaldehyde, such as trioxane anhydride or tetraoxane, and a cyclic ether, such as ethylene oxide, propylene oxide, 1,3-dioxolane, 1,3-propanedioformal, 1,4-butanediolformal, 1,5-pentanediolformal, 1,6-hexanediolformal, diethylene glycolformal, 1,3,5-trioxepane, or 1,3,6-trioxocane, in an organic solvent such as cyclohexane or benzene, then adding a Lewis acid catalyst such as boron trifluoride diethyl etherate to polymerize and decomposing the unstable ends.

[0036] For example, an oxymethylene copolymer can be selected in terms of the balance of heat resistance, mechanical strength, and impact resistance. In this case, the structure of the polyoxymethylene copolymer may be a linear structure, a branched structure, or a cross-linked structure, and

[0037] The constituent units of the comonomer other than the main chain oxymethylene group are oxyethylene (-(OCH2CH2) n-), oxypropylene(-(OCH2CH2CH2) n -), oxybutylene(-(OCH2CH2CH2CH2) n It is desirable to include branched oxyalkylene groups having 2 to 10 carbon atoms, such as -) branched oxyalkylene groups having 2 to 4 carbon atoms, particularly oxyethylene groups, from the perspective of improving the thermal stability of the polymer and the crystallinity of the moldability.

[0038] In addition, the comonomer may be ethylene oxide, 1,3-dioxolane, 1,3-dioxepane, or 1,3,5-trioxepane, and as an example, 1,3-dioxolane.

[0039] For example, the polyoxymethylene resin may be included in an amount of 95% to 99.8% by weight with respect to 100% by weight of the polyoxymethylene resin composition, for example, in an amount of 99% to 99.8% by weight, 99.5% to 99.8% by weight, or 99.5% to 99.6% by weight.

[0040] For example, the above polyoxymethylene resin has a melting point (T) measured by differential scanning calorimetry (DSC). m ) can be 160 ℃ to 180 ℃.

[0041]

[0042] dihydrazide compounds

[0043] Dihydrazide compounds can effectively capture formaldehyde gas generated from the decomposition of polyoxymethylene resin.

[0044] For example, the dihydrazide compound may be included in an amount of 0.01% to 1% by weight with respect to 100% by weight of the polyoxymethylene resin composition, and may be included in an amount of, for example, 0.01% to 0.3%, 0.01% to 0.2%, 0.01% to 0.1%, or 0.01% to 0.05% by weight.

[0045] If the dihydrazide compound is included in an amount of less than 0.01 weight% relative to 100 weight% of the above polyoxymethylene resin composition, the formaldehyde capture effect is insufficient, and formaldehyde emitted from the molded product cannot be effectively reduced, and if it is included in an amount of more than 1 weight%, the frequency of mold deposition may increase significantly due to unreacted material.

[0046] For example, the above dihydrazide compound may include adipic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, dodecanedioic dihydrazide, 1,12-dodecanedicarboxylic acid dihydrazide, or a combination thereof.

[0047]

[0048] urea compounds

[0049] Urea compounds can improve the heat resistance, moldability, and long-term dimensional stability of polyoxymethylene resin compositions, enhance mechanical properties, and increase thermal stability by reducing formaldehyde gas emissions.

[0050] For example, the urea compound may be included in an amount of 0.01% to 1% by weight with respect to 100% by weight of the polyoxymethylene resin composition, and may be included in an amount of, for example, 0.1% to 1% by weight, 0.1% to 0.3% by weight, 0.1% to 0.25% by weight, or 0.15% to 0.25% by weight.

[0051] If the urea compound is included in an amount of less than 0.01 weight% relative to 100 weight% of the above polyoxymethylene resin composition, the formaldehyde capture effect is insufficient, and the formaldehyde emitted from the molded article cannot be effectively reduced; if it is included in an amount of more than 1 weight%, the frequency of mold deposition due to unreacted material increases significantly and mechanical properties may decrease.

[0052] For example, the urea compound may include ethylene urea, (2,5-dioxo-4-imidazolidinyl)urea, N-(dioxomidazolidin-4-yl-)urea, or a combination thereof. As a specific example, when ethylene urea is used as the urea compound, the amount of deposition occurring in the resin composition and the molded article can be significantly reduced. For example, the ethylene urea may be 2-imidazolidone or imidazolidin-2-one, etc.

[0053] For example, the above urea compound may be in the form of flakes, pellets, or particles.

[0054] For example, with respect to the polyoxymethylene resin composition, the dihydrazide compound and the urea compound may be included in a weight ratio of 1:3 to 1:5.

[0055] If the weight ratio of the above dihydrazide compound and the above urea compound is less than 1:3, the amount of formaldehyde generated increases and a large amount of deposit may be generated during injection molding, and if it exceeds 1:5, a large amount of deposit may be generated during injection molding.

[0056]

[0057] Metal salt phosphate compounds

[0058] For example, the above polyoxymethylene resin composition may further include a metal salt phosphate-based compound.

[0059] The above metal salt phosphate-based compound plays a role in modifying the unstable end groups within the polyoxymethylene resin, thereby preventing the decomposition of the resin by heat during molding processing.

[0060] For example, the metal salt phosphate compound may be an ester compound containing a metal salt comprising Mg, Ca, Zn, Ba, Fe, or a combination thereof.

[0061] For example, the metal salt phosphate-based compound may include a compound represented by the following chemical formula 1, a compound represented by the following chemical formula 2, or a combination thereof.

[0062] [Chemical Formula 1]

[0063]

[0064] [Chemical Formula 2]

[0065]

[0066] In the above formulas 1 and 2, M may be a cation metal including Mg, Ca, Zn, Ba, Fe, or a combination thereof, and R1 may be an alkyl group having 12 to 32 carbon atoms.

[0067] For example, the metal salt phosphate-based compound may be included in an amount of 0.01% to 1% by weight with respect to 100% by weight of the polyoxymethylene resin composition, and may be included in an amount of, for example, 0.01% to 0.5% by weight, 0.05% to 0.5% by weight, 0.1% to 0.5% by weight, or 0.05% to 0.1% by weight.

[0068] If the metal salt phosphate-based compound is included in an amount of less than 0.01 weight% relative to 100 weight% of the above polyoxymethylene resin composition, it cannot sufficiently perform its role as a heat retardant, which may reduce the thermal stability of the polyoxymethylene resin composition, and if it is included in an amount exceeding 1 weight%, it may cause adverse effects such as slowing down or even increasing the formaldehyde reduction effect.

[0069]

[0070] Hindered phenolic antioxidants

[0071] For example, the polyoxymethylene resin composition may further include a hindered phenolic antioxidant.

[0072] For example, the hindered phenolic antioxidant is n-octadecyl-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)-propionate, triethyleneglycol-bis-[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)-propionate], 2,2'-methylenebis-(4-methyl-t-butylphenol), tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl propionate]methane, N,N'-bis-3-3(3',5'-di-t-butyl-4'-hydroxyphenyl)propionylhexamethylenediamine, N,N'-tetramethylene-bis-3-(3'-methyl-5'-t-butyl-4'-hydroxyphenol)propionyldia, It may include N,N'-bis-[3-(3,5-di-t-butyl-4-hydroxyphenol)propionyl]hydrazine, N-sarityroyl-N'-sarityridenhydrazine, 3-(N-sarityroyl)amino-1,2,4-triazole, N,N'-bis[2-{3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy}ethyl]oxyamide, or a combination thereof.

[0073] As a specific example, the hindered phenolic antioxidant may include triethylene glycol-bis-[3-(3-t-butyl-5-methyl 4-hydroxyphenyl)-propionate], tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, or a combination thereof.

[0074] For example, the hindered phenolic antioxidant may be included in an amount of 0.01% to 0.5% by weight with respect to 100% by weight of the polyoxymethylene resin composition, for example, 0.01% to 0.5% by weight, 0.05% to 0.5% by weight, 0.1% to 0.5% by weight, or 0.05% to 0.1% by weight.

[0075] If the hindered phenolic antioxidant is included in an amount of less than 0.01% by weight relative to 100% by weight of the above polyoxymethylene resin composition, it may be difficult for it to perform its role as an antioxidant, and if it is included in an amount of more than 0.5% by weight, the mechanical properties of the resin may be degraded.

[0076] Meanwhile, the polyoxymethylene resin composition may additionally include additives such as fillers like calcium carbonate, clay, silicon oxide, and mica powder, reinforcing agents like glass fibers, carbon fibers, and polyamide fibers, coloring agents, nucleating agents, plasticizers, release agents like ethylene bis stir and polyethylene wax, and lubricants, to the extent that performance is not impaired.

[0077]

[0078] A molded article according to another embodiment is manufactured from the aforementioned polyoxymethylene resin composition. Accordingly, it is possible to realize a molded article with significantly less deposit generation and very low formaldehyde gas emission.

[0079] For example, the above-mentioned molded article may have a formaldehyde gas emission of 2 mg / kg or less at 200 ℃ according to VDA-275 standards, and may, for example, be 1 mg / kg or less, 0.5 mg / kg or less, or 0.31 mg / kg or less.

[0080]

[0081] Specific embodiments of the invention are presented below. However, the embodiments described below are merely for the purpose of specifically illustrating or explaining the invention and should not limit the scope of the invention.

[0082] [Preparation Example: Preparation of Polyoxymethylene Resin Composition]

[0083] (Examples and Comparative Examples)

[0084] A polyoxymethylene resin composition was prepared by mixing the content of each component in the ratio shown in Table 1 below, based on 100% by weight of the polyoxymethylene resin composition.

[0085] POM 1)(Weight%) Dihydrazide Compound (Weight%) Urea Compound (Weight%) Dihydrazide Compound:Urea Compound (Weight Ratio) Metal Salt Phosphate Compound 7) hindered phenol-based antioxidant 8) (Weight%) 2) 3) 4) 5) 6) Example 1 99.6 0.05 --- 0.1 51: 30.10.1 Example 2 99.5 50.05 --- 0.21: 40.10.1 Example 3 99.5 0.05 --- 0.251: 50.10.1 Comparative Example 199.7 50.05 --- 0.10.1 Comparative Example 299.7 0.05 --- 0.05 1: 10.10.1 Comparative Example 399.6 50.05 --- 0.11: 20.10.1 Comparative Example 499.4 50.05 --- 0.31: 60.10.1 Comparative Example 5 99.7 0.1 --- 0.10.1 Comparative Example 699.70.1-----0.10.1 Comparative Example 799.550.25-----0.10.1 Comparative Example 899.60.2-----0.10.1 Comparative Example 999.550.25-----0.10.1 Comparative Example 1099.50.3-----0.10.1 Comparative Example 1199.75----0.05-0.10.1 Comparative Example 1299.7----0.1-0.10.1 Comparative Example 1399.75-0.05--- -0.10.1 Example 499.6-0.05--0.151:30.10.1 Example 599.55-0.05--0.21:40.10.1 Example 699.5-0.05--0.251:50.10.1 Comparative Example 1499.750.05-----0.10.1 Example 799.60.05--0.15-1:30.10.1 Example 899.550.05--0.2-1:40.10.1 Example 999.50.05--0.25-1:50.10.1 Comparative Example 1599.75--0.05---0.10.1 Example 1099.6--0.05-0.151:30.10.1 Example 1199.55--0.05-0.21:40.10.1 Example 1299.5--0.05-0.251:50.10.1

[0086] 1) Polyoxymethylene resin (Kolon Plastic, K300) 2) Sebacic acid dihydrazide (Japan finechem, SDH)

[0087] 3) Adipic acid dihydrazide (Japan finechem, ADH)

[0088] 4) Isophthalic acid dihydrazide (Otsuka Chemical, IDH)

[0089] 5) N-(dioxomidazolidin-4-yl-)urea (AKEMA, Allantoin)

[0090] 6) Ethyleneurea (Haihang Industry, Ethyleneurea.)

[0091] 7) Zinc Stearyl Phosphate (Sakai Chemical, LBT-1830)

[0092] 8) Hindered phenolic antioxidant (Songwon, Songnox 1010)

[0093]

[0094] [Experimental Example: Measurement of Physical Properties of Polyoxymethylene Resin Composition]

[0095] (1) Evaluation of formaldehyde gas emissions

[0096] Formaldehyde (FA) gas emissions were measured in accordance with VDA 275 standards using the following method.

[0097] First, the polyoxymethylene resin compositions according to Examples 1 to 12 and Comparative Examples 1 to 15 prepared above were injection molded into test specimens with a width of 40 mm, a length of 100 mm, and a thickness of 2 mm in accordance with the specifications required by VDA 275 to produce samples.

[0098] Next, the weight of the sample was measured after leaving it in a constant temperature and humidity room maintained at 23℃ and 50% relative humidity for more than 15 hours (W1).

[0099] 50 ml of distilled water was taken using a graduated cylinder and transferred into a 1 L polyethylene container, and the sample was hung on a hook on the inside of the polyethylene container lid to seal the lid. Then, the sealed sample was placed in a drying oven at 60°C for 3 hours, removed, and left at room temperature for 1 hour.

[0100] Next, 10 ml of acetylacetone solution and 10 ml of ammonium acetate solution were each placed into a 50 ml volumetric flask, and then the lid of the polyethylene container was opened and the weight of the sample was measured (W2).

[0101] 10 ml of the solution inside the polyethylene container was taken using a pipette and placed into a previously prepared volumetric flask. The flask was then incubated in a 40°C water bath for 15 minutes to develop color, after which it was removed and left at room temperature for at least one hour. The remaining solution was transferred to a cell measuring 10 mm by 10 mm, and the absorbance was measured at a wavelength of 412 nm. The absorbance of the blank distilled water was also measured using the same method.

[0102] The formula for calculating formaldehyde emission is as follows.

[0103] 1) Moisture (%) = {(W2-W1) / W1}X100

[0104] 2) Formaldehyde emission amount

[0105]

[0106] As = Absorbance of the analyzed sample

[0107] Ab = Absorbance of Blank Sample

[0108] f = slope of the UV calibration curve

[0109] m = mass of the sample (g)

[0110] H = Moisture content of the sample (%)

[0111] V = Volume of formaldehyde absorption solution (ml)

[0112] The amount of formaldehyde emitted was calculated using the above formula and is shown in Table 2 below.

[0113]

[0114] (2) Evaluation of sediment generation amount

[0115] After injecting the polyoxymethylene resin compositions according to Examples 1 to 12 and Comparative Examples 1 to 15 prepared above in an injection molding machine with a nozzle temperature of 230°C, the amount of deposited material was evaluated.

[0116] The amount of sediment generated is expressed as numbers from '1' to '10' ranging from 'none' to 'severe' and is shown in Table 2 below.

[0117] For reference, Fig. 1 is a photograph showing an injection molded product with a deposit amount of '1' (none), and Fig. 2 is a photograph showing an injection molded product with a deposit amount of '10' (severe).

[0118] Formaldehyde gas emission amount (200℃) (mg / kg) Amount of deposit generated Example 10.111 Example 20.071 Example 30.031 Comparative Example 10.237 Comparative Example 20.185 Comparative Example 30.173 Comparative Example 40.014 Comparative Example 50.1110 Comparative Example 60.0910 Comparative Example 70.0110 Comparative Example 80.0110 Comparative Example 90.0110 Comparative Example 100.0110 Comparative Example 112.931 Comparative Example 122.611 Comparative Example 130.358 Example 40.312 Example 50.281 Example 60.211 Comparative Example 143.610 Example 70.16 10 Example 80.11 10 Example 90.110 Comparative Example 15 0.4 17 Example 100.3 12 Example 110.282 Example 120.252

[0119] Referring to Table 2, it can be seen that the polyoxymethylene resin compositions prepared in Examples 1 to 12 have a very low amount of formaldehyde gas generation of 2 mg / kg or less. In addition, it can be seen that Examples 1 to 3, Examples 4 to 6, and Examples 10 to 12 have a very low amount of deposit generation.

[0120] Meanwhile, since Comparative Example 1 does not contain a urea compound, it can be confirmed that the amount of formaldehyde gas emitted is higher and the amount of deposition is significantly higher compared to Examples 1 to 3.

[0121] Comparative Examples 2, 3, and 4 did not satisfy the weight ratio of dihydrazide compound to urea compound of 1:3 to 1:5, so it can be confirmed that the amount of formaldehyde gas released generally increased and the amount of deposition was significantly higher compared to Examples 1 to 3.

[0122] Comparative Examples 5 to 10 do not contain urea compounds, so it can be confirmed that the deposition amount is significantly higher compared to the Examples.

[0123] Comparative Examples 11 and 12 do not contain dihydrazide compounds, so it can be confirmed that the amount of formaldehyde gas emitted is significantly higher compared to the examples.

[0124] Comparative Example 13, when compared to Examples 4 to 6, does not contain urea compounds, so it can be confirmed that the amount of formaldehyde gas released is higher and the amount of deposition is significantly higher.

[0125] It can be confirmed that Comparative Example 14 has a significantly higher amount of formaldehyde gas emission compared to Examples 7 to 9 because it does not contain urea compounds.

[0126] Comparative Example 15 can be seen to have a higher formaldehyde gas emission and significantly higher deposition amount compared to Examples 10 to 12 because it does not contain urea compounds.

[0127] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also included within the scope of the present invention.

[0128]

[0129] According to the polyoxymethylene resin composition of the present invention, even when manufactured under harsh injection molding conditions, the amount of deposits generated is significantly low and the amount of formaldehyde gas emitted is low, so the molded article can be widely used in various fields as an engineering resin.

Claims

1. Includes polyoxymethylene resin, dihydrazide compound, and urea compound, A polyoxymethylene resin composition having a weight ratio of the dihydrazide compound and the urea compound of 1:3 to 1:

5.

2. In Paragraph 1, A polyoxymethylene resin composition comprising 95% to 99.8% by weight of the polyoxymethylene resin with respect to 100% by weight of the polyoxymethylene resin composition.

3. In Paragraph 1, A polyoxymethylene resin composition having a melting point of 160°C to 180°C for the polyoxymethylene resin.

4. In Paragraph 1, A polyoxymethylene resin composition comprising 0.01% to 1% by weight of the dihydrazide compound relative to 100% by weight of the polyoxymethylene resin composition.

5. In Paragraph 1, A polyoxymethylene resin composition comprising the above dihydrazide compound adipic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, dodecanedioic dihydrazide, 1,12-dodecanedicarboxylic acid dihydrazide, or a combination thereof.

6. In Paragraph 1, A polyoxymethylene resin composition comprising 0.01% to 1% by weight of the urea compound relative to 100% by weight of the polyoxymethylene resin composition.

7. In Paragraph 1, A polyoxymethylene resin composition comprising the above urea compound, ethylene urea, (2,5-dioxo-4-imidazolidinyl)urea, or a combination thereof.

8. In Paragraph 1, The above polyoxymethylene resin composition further comprises a metal salt phosphate-based compound.

9. In Paragraph 8, A polyoxymethylene resin composition in which the metal salt phosphate-based compound is an ester-based compound containing a metal salt comprising Mg, Ca, Zn, Ba, Fe, or a combination thereof.

10. In Paragraph 8, A polyoxymethylene resin composition comprising 0.01% to 1% by weight of the metal salt phosphate-based compound with respect to 100% by weight of the polyoxymethylene resin composition.

11. In Paragraph 1, The above polyoxymethylene resin composition further comprises a hindered phenolic antioxidant.

12. In Paragraph 11, A polyoxymethylene resin composition comprising 0.01% to 0.5% by weight of the hindered phenolic antioxidant per 100% by weight of the polyoxymethylene resin composition.

13. A molded article manufactured from a polyoxymethylene resin composition according to any one of claims 1 to 12.

14. In Paragraph 13, The above-mentioned molded article is a molded article having a formaldehyde gas emission of 2 mg / kg or less at 200 ℃ according to VDA-275 standards.

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