KR20210038203A - Polyoxymethylene resins composition and molding procuced from the same - Google Patents

Abstract

The present invention relates to a polyoxymethylene resin composition. More particularly, the present invention relates to a polyoxymethylene resin composition, wherein an inorganic compound containing molybdenum and sulfur, a graft copolymer, a dihydrazide-based compound, and a zinc phosphate ester-based compound are added to and mixed with a polyoxymethylene copolymer. Thus, mechanical properties such as friction/abrasion resistance and elastic modulus are improved, and the amount of formaldehyde emitted is reduced below a standard value.

Description

Polyoxymethylene resins composition and molding procuced from the same

The present invention relates to a polyoxymethylene resin composition and a molded article.

Polyoxymethylene resin is applied to gears and rollers because of its excellent fatigue resistance, creep resistance, friction/abrasion resistance, organic chemical resistance, and long-term dimensional stability, and is used in various fields such as automobiles, office equipment, and household materials. .

As the use of polyoxymethylene resin is expanded and diversified, the properties required for polyoxymethylene are gradually increasing, and polyoxymethylene is applied to sliding drive parts, door latch parts, gears, etc. that are widely used in automobiles and miscellaneous goods. Resins are required to have excellent friction/abrasion properties for a long time. In addition, a low amount of formaldehyde emission has become important as an eco-friendly issue for VOC reduction in recent years.

As a conventional technique for improving the friction/abrasion resistance of polyoxymethylene resin, a method of adding silicone oil to polyoxymethylene resin (Korean Patent No. 10-0855130, Japanese Laid-Open Patent No. 2590513), polytetrafluoro Method of adding roethylene (Korean Patent Laid-Open Patent No. 10-2018-0129771), method of adding ethylene graft copolymer (Korean Laid-Open Patent No. 10-2019-0041230), method of adding polyethylene wax (Korean Patent Laid-Open Patent No. 10-2015-0078284), etc.), but there is a limitation in that only one function of low coefficient of friction, non-abrasion, or long-term wear is possible because one type of anti-wear agent is used in the case of using the conventional technology.

In addition, polyoxymethylene resins are easily decomposed under heat oxidation, acidity, and atmosphere due to their chemical structure, and release formaldehyde. As a conventional technique for reducing the amount of formaldehyde emission, a method of adding an acrylamide and a boron compound to a polyoxymethylene resin (Korean Patent No. 10-1646977, Japanese Patent Publication No. 1998-001592), and an alanine compound added. Method (Japanese Patent Laid-Open Patent No. 1984-213752), method of adding a melamine derivative (Japanese Patent Laid-Open No. 1994-73267), method of adding a 1,12-dodecanedicarboxylic acid dihydrazide compound (Korean Patent Laid-Open Patent No. 10-2006-0031395), a method of adding an aliphatic dihydrazide compound having 4 to 12 carbon atoms (Japanese Patent Laid-Open Patent No. 1998-298401). It cannot be sufficiently reduced.

Accordingly, the development of technology for polyoxymethylene resins that can effectively reduce formaldehyde emission while having high mechanical properties while effectively improving the friction/abrasion characteristics of polyoxymethylene resins is a situation that is constantly required.

The present invention is to provide a polyoxymethylene resin composition and a molded article manufactured therefrom which significantly improves the friction/abrasion resistance properties required for polyoxymethylene resin, reduces the amount of formaldehyde emission, and improves mechanical properties such as elastic modulus. do.

Accordingly, as a first preferred embodiment of the present invention, a polyoxymethylene resin; Inorganic compounds including molybdenum and sulfur; Graft copolymer; A dihydrazide compound represented by the following formula (1); It includes a zinc phosphate ester compound represented by the following Formula 2 or Formula 3, and the inorganic compound including molybdenum and sulfur provides a polyoxymethylene resin composition having an average particle diameter of 0.4 μm to 5 μm.

[Formula 1]

로 표시되는 구조일 수 있다.In Formula 1, R1 is a C ₄ ~ C ₁₀ alkane system or

It may be a structure represented by.

[Formula 2]

In Formula 2, R ₂ is a C ₁₆ ~ C ₂₄ alkyl group.

[Formula 3]

In Formula 3, R ₂ is a C ₁₆ ~ C ₂₄ alkyl group.

The polyoxymethylene resin composition comprises 0.50 to 6.00 parts by weight of the inorganic compound containing molybdenum and sulfur, 1 to 6 parts by weight of the graft copolymer, and the dihydrazide-based compound based on 100 parts by weight of the polyoxymethylene resin. It is characterized in that it contains 0.05 to 0.5 parts by weight and 0.05 to 1.0 parts by weight of the zinc phosphate ester compound.

The graft copolymer includes, as a main chain, at least one selected from polypropylene and polycarbonate, and polystyrene, acrylonitrilie-styrene copolymer. ), butyl acrylate-methyl methacrylate (Butyl acrylate-Methyl methacrylate), ethylene glycidyl methacrylate copolymer (Ethylene-glycidyl methacrylate copolymer) and ethylene ethyl acrylate copolymer (Ethylene-ethyl acrylate copolymer) selected from It is characterized in that at least one is a copolymer prepared by grafting.

The dihydrazide-based compound is adipic acid dihydrazide, sebacic acid dihydrazide, 1,12-dodecanedicarboxylic acid dihydrazide (1, 12-Dodecanedicarboxylic acid dihydrazide) and isophthalic acid dihydrazide.

The zinc phosphate ester compound is selected from zinc atearyl phosphate, zinc behenic phosphate, zinc arachidonic phosphate, and zinc palmitic phosphate. It is characterized in that it is at least one or more.

As another preferred embodiment of the present invention, the present invention provides a molded article manufactured from the above-described polyoxymethylene resin composition.

The molded article is characterized in that the friction coefficient is 0.2 or less and the specific wear amount is 0.015 mm ³ /Nkm or less, and the formaldehyde emission amount at 220° C. based on VDA 275 measurement is 5.00 mg/kg or less.

The polyoxymethylene resin composition according to the present invention improves long-term abrasion resistance and non-abrasion, reduces formaldehyde emission, and improves mechanical properties such as elastic modulus. It can also be applied in various ways.

According to a preferred embodiment of the present invention, polyoxymethylene resin; Inorganic compounds including molybdenum and sulfur; Graft copolymer; A dihydrazide compound represented by the following formula (1); It is to provide a polyoxymethylene resin composition comprising a zinc phosphate ester compound represented by the following Formula 2 or Formula 3, and the inorganic compound including molybdenum and sulfur having an average particle diameter of 0.4 μm to 5 μm.

[Formula 1]

로 표시되는 구조일 수 있다.In Formula 1, R ₁ is a C ₄ ~ C ₁₀ alkane system or

It may be a structure represented by.

[Formula 2]

In Formula 2, R ₂ is a C ₁₆ ~ C ₂₄ alkyl group.

[Formula 3]

In Formula 3, R ₂ is a C ₁₆ ~ C ₂₄ alkyl group.

Hereinafter, the present invention will be described in detail.

The polyoxymethylene resin used in the present invention refers to a homopolymer, a copolymer, or a terpolymer having a general oxymethylene group (-(-OCH ₂ )n-) as a main unit, and the copolymer used in the present invention is 1 ,3-dioxolane (1,3-Dioxolane) was used

The polyoxymethylene copolymer can be obtained by cationic random copolymerization of a cyclic oligomer of trioxane or tetraoxane, preferably a mixture of a cyclic oligomer of trioxane and a 1,3-dioxolane comonomer. The polyoxymethylene copolymer of the present invention is obtained by adding the 1,3-dioxolane comonomer to trioxane as the main monomer and then cationic random copolymerization using a Lewis acid catalyst. An oxymethylene copolymer can be obtained.

The structure of the polyoxymethylene copolymer may have a branched or crosslinked structure as well as a linear structure.

_{The polyoxymethylene copolymer is oxyethylene (-(OCH 2} CH ₂ ) _n -), oxypropylene (-(OCH ₂ CH ₂ CH ₂ ) _n -), as constituent units of comonomers other than the main chain oxymethylene group, C2-C10 or less branched oxyalkylene groups, such as oxybutylene (-(OCH ₂ CH ₂ CH ₂ CH ₂ ) _n -), etc. are mentioned, Among them, C2-C4 or less branched oxy An alkylene group is mentioned, and an oxyethylene group is especially preferable.

In the polyoxymethylene copolymer, the comonomer is ethylene oxide, 1,3-dioxolane, 1,3-dioxepane, 1,3 It is preferable that it is ,5-trioxepane (1,3,5-trioxepane), and especially it is more preferable that 1,3-dioxolane is copolymerized.

The inorganic compound containing molybdenum and sulfur used in the present invention serves to improve the friction/abrasion resistance of the polyoxymethylene resin composition and reduce the amount of formaldehyde released. As a specific example, it may be at least one selected from molybdenum sulfide such as molybdenum sulfide, molybdenum disulfide, and molybdenum trisulfide, and molybdenum disulfide is suitable.

The inorganic compound containing molybdenum and sulfur is preferably 0.50 to 6.00 parts by weight, more preferably 1.00 to 2.00 parts by weight based on 100 parts by weight of the polyoxymethylene resin composition. If the content is less than 1 part by weight, the effect of improving the friction/abrasion characteristics cannot be confirmed, and if it exceeds 2.00 parts by weight, mechanical properties may be deteriorated, leading to a risk of product damage.

The inorganic compound containing molybdenum and sulfur may have an average particle diameter of 0.4 μm to 5 μm. When the average particle diameter is satisfied, molybdenum disulfide may be effectively dispersed in the polyoxymethylene resin.

The graft copolymer used in the present invention serves to improve the friction/abrasion properties of the polyoxymethylene resin composition.As a specific example, polyethylene included in the main chain is polypropylene and polycarbonate. It may be one or more selected from among, but most preferably, polyethylene is suitable.

The copolymer grafted to the main chain is polystyrene (Polystyrene), acrylonitrilie-styrene copolymer (Acrtlonitrilie-styrene copolymer), butyl acrylate methyl methacrylate (Butyl acrylate-Methyl methacrylate), ethylene glycidyl methacrylate copolymer It may be one or more selected from an ethylene-glycidyl methacrylate copolymer and an ethylene-ethyl acrylate copolymer, most preferably polystyrene.

The graft copolymer is preferably 1.00 to 6.00 parts by weight, more preferably 2.00 to 3.00 parts by weight based on 100 parts by weight of the polyoxymethylene resin. If the content is less than 1.00 parts by weight, the effect of improving the friction/abrasion characteristics cannot be confirmed, and if the content is more than 6.00 parts by weight, mechanical properties may be deteriorated, resulting in a risk of product damage.

The dihydrazide compound used in the present invention plays a role of effectively capturing formaldehyde, and is a compound represented by the following formula (1).

[Formula 1]

로 표시되는 구조일 수 있다.In Formula 1, R ₁ is a C ₄ ~C ₁₀ alkane system or

It may be a structure represented by.

Specific examples thereof include adipic acid dihydrazide, sebacic acid dihydrazide, 1,12-dodecanedicarboxylic acid dihydrazide (1,12-Dodecanedicarboxylic acid dihydrazide), isop It may include one or more dihydrazide compounds selected from isophthalic acid dihydrazide.

The dihydrazide-based compound is preferably 0.05 to 0.5 parts by weight, more preferably 0.1 to 0.2 parts by weight based on 100 parts by weight of the polyoxymethylene resin. If the content is less than 0.05, the formaldehyde trapping effect is insufficient, so that formaldehyde emitted from the molded product cannot be effectively reduced. If the content is more than 0.5 parts by weight, the occurrence of mold deposits may increase due to unreacted substances. .

The zinc phosphate ester compound used in the present invention is a compound represented by the following formula (2) or (3), and a fatty acid ester series having 16 to 22 carbon atoms is preferable.

[Formula 2]

In Formula 2, R ₂ is a C ₁₆ ~ C ₂₄ alkyl group.

[Formula 3]

In Formula 3, R ₂ is a C ₁₆ ~ C ₂₄ alkyl group.

As a specific example thereof, at least selected from zinc stearyl phosphate, zinc behenic phosphate, zinc arachidonic phosphate, zinc palmitic phosphate, and mixtures thereof. It may contain one zinc phosphate ester compound.

The zinc phosphate ester compound that improves thermal stability in the present invention is preferably 0.05 to 1.0 parts by weight, more preferably 0.1 to 0.3 parts by weight, based on 100 parts by weight of the polyoxymethylene resin. When the content is less than 0.05, the thermal stability effect is insufficient, and the formaldehyde reduction effect is deteriorated, and even when the content is more than 1.0 part by weight, there is a disadvantage in that the formaldehyde reduction effect cannot be expressed.

In addition, the composition of the present invention includes fillers such as calcium carbonate, clay, silicon oxide, mica powder, reinforcing agents such as glass fibers, carbon fibers, and polyamide fibers, and coloring agents within the range not impairing the effects of the present invention. , Nucleating agents, plasticizers, hindered phenol compounds, antioxidants such as phosphate compounds, release agents such as ethylene bis stir, polyethylene wax, and additives such as lubricants may be optionally contained.

According to the present invention, as described above, a polyoxymethylene resin composition capable of improving long-term wear resistance and non-abrasion amount, reducing formaldehyde emission amount, and improving mechanical properties such as elastic modulus can be prepared.

According to another preferred embodiment of the present invention, it is to provide a molded article prepared from the above-described polyoxymethylene resin composition.

The molded article is characterized in that the friction coefficient is 0.2 or less and the specific wear amount is 0.015 mm ³ /Nkm or less, and the formaldehyde emission amount at 220° C. based on VDA 275 measurement is 5.00 mg/kg or less. The lower the coefficient of friction, the amount of non-abrasion, and the amount of formaldehyde released, the lower the lower limit or the upper limit thereof is meaningless in that it has excellent physical properties.

[Example]

Hereinafter, the present invention will be described in more detail through examples. These examples are only for describing the present invention in more detail, and the present invention is not limited thereto.

Examples 1 to 5 and Comparative Examples 1 to 9

In polyoxymethylene resin (a) polyoxymethylene resin (KOLON PLASTIC, KOCETAL K300) (b) Molybdenum disulfide (Climax Molybdeum Company, LM12, average diameter 0.7 μm), (c) Molybdenum disulfide (Sumico lubricant, Molypowder-C) , Average diameter 0.3 μm), (d) Molybdenum disulfide (Sumico lubricant, Molypowder-PA average diameter 5.2 μm), (e) Polystyrene grafted polyethylene (NOF corporation, A1100), (f) Polyethylene (NOF corporation, A1401) , (g) silicone (Genioplast, Pellet S), (h) polytetrafluoroethylene (POLIS, K301FDA) (i) ethylene acrylate (Dupont, PTW) (j) adipic acid dihydrazide (Japan finechem company INC , ADH) and (k) zinc stearyl phosphate (Sakai chemical, LBT-1830) were used as the contents of Table 1 to prepare a polyoxymethylene resin composition. At this time, the contents shown in Table 1 are parts by weight based on 100 parts by weight of the polyoxymethylene resin.

(a) (b) (c) (d) (e) (f) (g) (h) (i) (j) (k) Example 1 100 0.50 0.00 0.00 3.00 0.00 0.00 0.00 0.00 0.20 0.30 Example 2 100 1.00 0.00 0.00 3.00 0.00 0.00 0.00 0.00 0.20 0.30 Example 3 100 2.00 0.00 0.00 3.00 0.00 0.00 0.00 0.00 0.20 0.30 Example 4 100 3.00 0.00 0.00 3.00 0.00 0.00 0.00 0.00 0.20 0.30 Example 5 100 6.00 0.00 0.00 3.00 0.00 0.00 0.00 0.00 0.20 0.30 Example 6 100 1.00 0.00 0.00 1.00 0.00 0.00 0.00 0.00 0.20 0.30 Example 7 100 1.00 0.00 0.00 6.00 0.00 0.00 0.00 0.00 0.20 0.30 Comparative Example 1 100 1.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Comparative Example 2 100 1.00 0.00 0.00 3.00 0.00 0.00 0.00 0.00 0.00 0.00 Comparative Example 3 100 1.00 3.00 0.00 0.00 3.00 0.00 0.00 0.00 0.20 0.30 Comparative Example 4 100 1.00 0.00 3.00 0.00 0.00 3.00 0.00 0.00 0.20 0.30 Comparative Example 5 100 1.00 0.00 0.00 0.00 0.00 0.00 3.00 0.00 0.20 0.30 Comparative Example 6 100 1.00 0.00 0.00 0.00 0.00 0.00 0.00 3.00 0.20 0.30 Comparative Example 7 100 1.00 0.00 0.00 3.00 0.00 0.00 0.00 0.00 0.00 0.30 Comparative Example 8 100 1.00 0.00 0.00 3.00 0.00 0.00 0.00 0.00 0.20 0.00 Comparative Example 9 100 0.00 1.00 0.00 0.00 0.00 0.00 0.00 0.00 0.20 0.30 Comparative Example 10 100 0.00 0.00 1.00 0.00 0.00 0.00 0.00 0.00 0.20 0.30

Property evaluation

Physical properties of the polyoxymethylene resin compositions prepared in Examples and Comparative Examples were measured by the following method, and the results are shown in Table 2 below.

1. Tensile modulus

It was measured according to ISO 527-1/-2 standards.

2. Flexural modulus

It was measured according to the ISO 178 standard.

3. Formaldehyde emission amount

It was measured according to the standard of VDA 275 (German Automobile Industry Association Standard). As the test piece, a square specimen having a size of 100 mm ⅹ 40 mm ⅹ 2 mm was used. Specimens were prepared by injection at 190°C, general conditions, and 220°C high temperature conditions at different temperatures during injection.

(1) 50 ml of distilled water was put in a polyethylene container, and the test piece was suspended in the air and left at 60° C. for 3 hours in a sealed state.

(2) After taking out the container, the test piece was taken after allowing it to stand at room temperature for 1 hour.

(3) Distilled water in a polyethylene container was reacted using an acetylacetone colorimetric method, and then the amount of formaldehyde absorbed was measured using a UV Spectrometer.

4. Friction/abrasion resistance evaluation

A trust type friction wear tester manufactured according to ASTM 3702 was used, and a cylindrical injection-molded specimen was injected and used as a sample, and SUS304 material was used as the counterpart material. The measurement sample was fixed on the upper side, attached to the counter material on the lower side so as to be horizontal, and then rotated the counter material clockwise to measure the dynamic friction coefficient, and the specific amount of wear was calculated. The friction/wear test conditions were fixed at a load of 7 kgf, a wear rate of 20 cm/s, and an evaluation time of 30 minutes.

Tensile modulus
(MPa) Flexural modulus
(MPa) Formaldehyde
Emission
(mg/kg) Formaldehyde
Emission
220℃
(mg/kg) Coefficient of friction Non-wear amount
(mm3/N-Km) Example 1 61 2500 ≤ 1 ≤ 1 0.19 0.013 Example 2 65 2600 ≤ 1 ≤ 1 0.15 0.001 Example 3 65 2600 ≤ 1 ≤ 1 0.15 0.001 Example 4 62 2600 ≥ 1 ≥ 50 0.14 0.016 Example 5 62 2650 ≥ 1 ≥ 50 0.14 0.022 Example 6 62 2550 ≤ 1 ≤ 1 0.22 0.002 Example 7 60 2400 ≤ 1 ≤ 1 0.16 0.001 Comparative Example 1 65 2550 ≤ 1 ≤ 1 0.27 0.016 Comparative Example 2 63 2500 ≥ 50 ≥ 50 0.21 0.007 Comparative Example 3 60 2500 ≤ 1 ≤ 1 0.22 0.001 Comparative Example 4 65 2550 ≤ 1 ≤ 1 0.36 0.001 Comparative Example 5 62 2500 ≤ 1 ≤ 1 0.24 0.001 Comparative Example 6 62 2500 ≤ 1 ≤ 1 0.17 0.001 Comparative Example 7 62 2500 ≥ 1 ≥ 1 0.18 0.001 Comparative Example 8 62 2500 ≥ 1 ≥ 5 0.18 0.001 Comparative Example 9 61 2520 ≥ 50 ≥ 50 0.22 0.021 Comparative Example 10 60 2450 ≥ 50 ≥ 50 0.25 0.010

As can be seen from Table 2 above, as a result of physical property evaluation, Examples 2 and 3 according to the present invention are polyoxymethylene resin, graft copolymer, dihydrazide compound represented by Formula 1, Formula 2 or Formula 3 It was confirmed that the tensile modulus, flexural modulus, formaldehyde emission amount, and friction/abrasion resistance were all excellent as including the zinc phosphate ester compound represented by and preferably including the weight range of the inorganic compound including molybdenum and sulfur. Became.

On the other hand, Comparative Examples 1 to 8 do not contain at least one or more of the constituent elements of the present invention, and Comparative Examples 9 and 10 are those outside the range of the average particle diameter of the inorganic compound containing molybdenum and sulfur, the tensile modulus , It was confirmed that at least some of the flexural modulus, formaldehyde emission, and friction/abrasion resistance decreased.

The above description of the present invention is for illustrative purposes only, and those of ordinary skill in the technical field to which the present invention pertains will be able to understand that it is possible to easily transform it into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it is to be understood that the embodiments described above are illustrative and non-limiting in all respects.

Claims (7)

Polyoxymethylene resin; Inorganic compounds including molybdenum and sulfur; Graft copolymer; A dihydrazide compound represented by the following formula (1); Including a zinc phosphate ester-based compound represented by the following formula (2) or (3),
The inorganic compound containing molybdenum and sulfur is a polyoxymethylene resin composition having an average particle diameter of 0.4 μm to 5 μm.
[Formula 1]

In Formula 1, R ₁ is a C ₄ ~ C ₁₀ alkane system or

It may be a structure represented by.
[Formula 2]

In Formula 2, R ₂ is a C ₁₆ ~ C ₂₄ alkyl group.
[Formula 3]

In Formula 3, R ₂ is a C ₁₆ ~ C ₂₄ alkyl group. The method of claim 1, wherein the polyoxymethylene resin composition comprises 0.50 to 6.00 parts by weight of an inorganic compound containing molybdenum and sulfur, and 1 to 6 parts by weight of the graft copolymer, based on 100 parts by weight of the polyoxymethylene resin. A polyoxymethylene resin composition comprising 0.05 to 0.5 parts by weight of a dihydrazide compound and 0.05 to 1.0 parts by weight of the zinc phosphate ester compound. The method of claim 1, wherein the graft copolymer comprises at least one selected from polypropylene and polycarbonate as a main chain, and polystyrene, acrylonitrile styrene copolymer Polymer (Acrylonitrilie-styrene copolymer), butyl acrylate methyl methacrylate (Butyl acrylate-Methyl methacrylate), ethylene glycidyl methacrylate copolymer (Ethylene-glycidyl methacrylate copolymer) and ethylene ethyl acrylate copolymer (Ethylene-ethyl methacrylate) acrylate copolymer) polyoxymethylene resin composition, characterized in that the copolymer is produced by grafting at least one selected from the. The method of claim 1, wherein the dihydrazide-based compound is adipic acid dihydrazide, sebacic acid dihydrazide, 1,12-dodecanedicarboxylic acid dihydrazide ( 1, 12-Dodecanedicarboxylic acid dihydrazide) and isophthalic acid dihydrazide (Isophthalic acid dihydrazide) polyoxymethylene resin composition, characterized in that at least one selected from. The method of claim 1, wherein the zinc phosphate ester compound is zinc stearyl phosphate, zinc behenic phosphate, zinc arachidonic phosphate, zinc palmitic phosphate. phosphate) and a mixture thereof. A molded article manufactured from the resin composition of any one of claims 1 to 5. The molded article according to claim 6, wherein the molded article has a friction coefficient of 0.2 or less and a specific wear amount of 0.015 mm ³ /Nkm or less, and a formaldehyde emission amount at 220° C. based on VDA 275 measurement is 5.00 mg/kg or less.