KR20180039359A - Polyoxymethylene Resin Composition and Molding Product Prepared By Using The Same - Google Patents

Abstract

The present invention relates to a polyoxymethylene resin composition and a molded product prepared by using the same, wherein the polyoxymethylene resin composition comprises: polyoxymethylene; and 0.01 to 0.2 parts by weight of alkaline earth metal hydroxide, 0.05 to 0.5 parts by weight of a dihydrazide compound, and 0.05 to 0.5 parts by weight of a zinc phosphate ester compound based on 100 parts by weight of the polyoxymethylene. The present invention provides the polyoxymethylene resin composition which can reduce the formaldehyde emission and inhibit the mold deposit formation.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyoxymethylene resin composition and a molded article obtained from the same,

The present invention relates to a polyoxymethylene resin composition capable of suppressing the formation of mold depreciation while reducing formaldehyde emission, and a molded article produced using the same.

Polyoxymethylene (POM) resin has excellent mechanical properties, rigidity, creep resistance, chemical resistance, friction / wear characteristics, long term durability, and is known as crystalline engineering plastic with high crystallinity. Utilizing this feature, POM is used in a wide range of fields such as electronic parts, automobile parts, and industrial parts. In recent years, demands for the quality of polyoxymethylene resin have been advanced according to expansion and diversification of applications.

Mainly required properties are that the mechanical properties will not be deteriorated during molding process, no odor will be generated (reduction in formaldehyde emission), and mold surface will not be contaminated. Particularly, due to the chemical structural characteristics of the polyoxymethylene resin, it is likely to decompose in a heated oxidizing atmosphere, an acidic or alkaline atmosphere, and the decomposition of the polymer occurs mainly in a high temperature and high processing. The formaldehyde generated in this process is chemically oxidized And the formation of formaldehyde may adversely affect the heat resistance of the resin due to these materials, or may cause various problems such as corrosion of metal parts or discoloration during molding. Therefore, the problem of formaldehyde generation in polyoxymethylene The method to solve has long been studied.

As a method for reducing the amount of formaldehyde emission, a method of adding acrylamide and a boron compound to a polyoxymethylene resin (JP-A No. 10-1592), a method of adding an alanine compound to a polyoxymethylene resin 59-213752), a method in which a melamine derivative is added to a polyoxymethylene resin (Japanese Patent Laid-Open No. 94-73267), a method in which a phenol compound or a nitrogen compound is added to enhance the thermal stability and antioxidative property of a polyoxymethylene resin (Japanese Patent Laid-Open No. 73-88135). However, the amount of formaldehyde generated can not be sufficiently reduced.

Further, a method of adding 1,12-dodecanedicarboxylic acid dihydrazide compound (Korean Published Unexamined Patent Application No. 10-2006-0031395) as a technique for reducing the amount of formaldehyde generated, adding an aliphatic dihydrazide compound having 4 to 12 carbon atoms (Japanese Patent Application Laid-Open No. 10-298401), and the like. However, even if the amount of formaldehyde generated can be sufficiently reduced, the mold release by molding of the additive deposit is increased, and the use thereof is limited, and it has been found that it has a problem that it can not sufficiently suppress formaldehyde emission at high temperatures.

Accordingly, it has been found through the present invention that by combining a dihydrazide additive and a zinc phosphate ester compound together with polyoxymethylene in the presence of an alkaline earth metal hydroxide, it is possible to reduce formaldehyde emission, Methylene resin composition.

A first preferred embodiment of the present invention for solving the above problems is a polyoxymethylene; And 0.01 to 0.2 parts by weight of an alkaline earth metal hydroxide, 0.05 to 0.5 parts by weight of a dihydrazide compound, and 0.05 to 0.5 parts by weight of a zinc phosphate ester compound based on 100 parts by weight of the polyoxymethylene.

Wherein the polyoxymethylene resin may be the melting point (T _m) is 160 to 180 ℃ as measured by differential scanning calorimetry (DSC), wherein the alkaline earth metal hydroxide is calcium hydroxide according to the first embodiment (Calcium hydroxide), At least one selected from the group consisting of magnesium hydroxide, strontium hydroxide and barium hydroxide.

The above-mentioned dihydrazide compounds may also be used in combination with adipic acid dihydrazide, sebacic acid dihydrazide, 1,12-dodecanedicarboxylic acid dihydrazide, acid dihydrazide and isophthalic acid dihydrazide, and the zinc phosphate ester compound may be at least one selected from the group consisting of zinc stearyl phosphate, zinc behenic phosphate Zinc behenic phosphate, Zinc arachidonic phosphate, Zine palmitic phosphate, and a mixture thereof.

In the present invention, the composition according to the first embodiment may have formaldehyde emission of 2.00 mg / kg or less based on VDA 275 measurement.

In order to solve the above problems, the present invention provides a molded article formed from the resin composition of the first embodiment as a second preferred embodiment of the present invention.

According to the present invention, the performance is maintained even at a high temperature while remarkably reducing the amount of formaldehyde emission, and it is possible to inhibit the formation of mold depreciation and to various applications such as automobile interior / exterior materials, electric / electronic products and cosmetic containers Can be provided.

TECHNICAL FIELD The present invention relates to a polyoxymethylene resin composition which retains its performance even at a high temperature and is inhibited from mold depreciation, and specifically relates to polyoxymethylene; And 0.01 to 0.2 parts by weight of an alkaline earth metal hydroxide, 0.05 to 0.5 part by weight of a dihydrazide compound and 0.05 to 0.5 part by weight of a zinc phosphate ester compound based on 100 parts by weight of the polyoxymethylene. And to provide a molded article produced therefrom.

Hereinafter, each component of the resin composition of the present invention will be described in more detail.

Polyoxymethylene

The polyoxymethylene of the present invention includes an oxymethylene- (OCH ₂ ) n - group as a repeating unit, and is an oxymethylene homopolymer in which both ends are blocked by an ester group or an ether group, or a polymer chain comprising oxymethylene monomer units An oxymethylene-based copolymer in which an oxyalkylene unit having 2 to 8 carbon atoms is randomly inserted into the main chain and both ends of the polymer are blocked with an ester or an ether group, or a terpolymer.

In the present invention, the polyoxymethylene resin serves as a base resin of the resin composition, secures the basic mechanical and chemical properties of the resin, and particularly performs a function important for abrasion resistance. In the present invention, the polyoxymethylene is not particularly limited as long as it is a commonly used polyoxymethylene, but it is more preferable that the melting point (T _m ) measured by differential scanning calorimetry (DSC) is 160 to 180 ° C .

Although the present invention is not particularly limited thereto, the oxymethylene homopolymer and the oxymethylene-based copolymer may be prepared by the following method. First, the above-mentioned oxymethylene homopolymer is polymerized by introducing anhydrous formaldehyde 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, filtering the polymer, By heating in acetic anhydride in the presence of sodium to acetylate the end.

The oxymethylene-based copolymer may be obtained by copolymerization of a cyclic oligomer of formaldehyde such as, for example, anhydrous trioxane or tetraoxane and a cyclic oligomer of formaldehyde such as ethylene oxide, propylene oxide, 1,3-dioxolane, But are not limited to, for example, 1,4-butane diol, 1,4-butane diol, 1,4-butane diol, 1,5- It is possible to prepare a cyclic ether by dissolving it in an organic solvent such as cyclohexane or benzene or the like, adding a Lewis acid catalyst such as boron triflate diethylether to polymerize and decomposing the unstable terminal have.

In the present invention, it may be preferable to select an oxymethylene copolymer from the viewpoint of balance of heat resistance, mechanical strength and impact resistance. At this time, the structure of the polyoxymethylene copolymer may have not only a linear structure but also branched (branched) and crosslinked (crosslinked) structures. As a constituent unit of the comonomer other than the oxymethylene group as the main chain, _{(- (OCH 2 CH 2)} n-), polyoxypropylene _{(- (OCH 2 CH 2 CH} 2) n-), oxybutylene-carbon atoms such as _{((OCH 2 CH 2 CH 2} CH 2) n-) 2 From 10 to less than 10 branched oxyalkylene groups, especially oxyalkylene groups having 2 to 4 carbon atoms and containing oxyethylene groups, are preferred from the viewpoints of improving the thermal stability of the polymer and improving the crystallinity of the formability Do. The comonomer may also be selected from the group consisting of ethylene oxide, 1,3-dioxolane, 1,3-dioxepane, 1,3,5-trioxepane, 1,3,5-trioxepane). Of these, 1,3-dioxolane is more preferably copolymerized.

Alkaline earth metal hydroxides

In the present invention, the metastable terminal of the alkaline earth metal hydroxide POM is decomposed to reduce the generation of formaldehyde which may occur during the secondary processing, thereby improving the thermal stability of the POM. At this time, specific examples of the alkaline earth metal hydroxides include calcium hydroxide, magnesium hydroxide, strontium hydroxide, and barium hydroxide. Among them, calcium hydroxide has POM metastable terminal decomposition And may be particularly desirable in terms of its role. The alkaline earth metal hydroxides may be decomposed to POM metastable terminal end by the difference of reactivity of metals. However, optimal POM metastable end termination can be possible in calcium system rather than magnesium system.

In the present invention, the alkaline earth metal hydroxide is preferably 0.01 to 0.2 parts by weight based on 100 parts by weight of the polyoxymethylene resin. When the amount is less than 0.01, the terminal decomposing effect is insufficient and the amount of formaldehyde emission is high, If it is more than 0.2, the excessive decomposition causes an increase in the amount of formaldehyde emission and a problem due to discoloration.

Dehydrazide system  compound

In the present invention, the dihydrazide compound may be represented by the following formula (1), and it can effectively capture formaldehyde. More preferably, in the present invention, the dihydrazide compound is selected from the group consisting of adipic acid dihydrazide, sebacic acid dihydrazide, 1,12-dodecanedicarboxylic acid dihydrazide ( 1,12-dodecanedicarboxylic acid dihydrazide, and isophthalic acid dihydrazide. The dihydrazide compound may be at least one compound selected from the group consisting of 1,12-dodecanedicarboxylic acid dihydrazide and isophthalic acid dihydrazide.

[Chemical Formula 1]

이다.In the formula (1), R ₁ is an alkyl group of C 4, C 8 or C 10

to be.

In the present invention, the amount of the dihydrazide compound capturing the formaldehyde gas 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. When the amount of formaldehyde is less than 0.05, the formaldehyde trapping effect is insufficient and the formaldehyde released from the molded article can not be effectively reduced. When the amount of the formaldehyde is more than 0.5 part by weight, mold depreciation may occur due to the unreacted material.

zinc Phosphate Ester system  compound

In the present invention, the zinc phosphate ester compound is represented by the following formula (2) or (3), and is preferably a fatty acid ester of 16 to 22 carbon atoms. More preferably, at least one of Zinc stearyl phosphate, Zinc behenic phosphate, Zinc arachidonic phosphate, Zine palmitic phosphate and mixtures thereof, Lt; RTI ID = 0.0 > zinc phosphate ester < / RTI >

(2)

(3)

In the general formulas (2) and (3), R ₂ is an alkyl group of C 16 to C ₂₄ .

The zinc phosphate ester compound that improves thermal stability in the present invention 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. When the content of the zinc-phosphate ester compound is less than 0.05, the effect of reducing the formaldehyde is inferior due to the lack of thermal stability effect. If the content of the zinc-formate ester compound is more than 0.5 parts by weight, the incidence of the mold- have.

The composition of the present invention may contain a filler such as calcium carbonate, clay, silicon oxide or mica powder, a glass fiber, a carbon fiber, a polyamide (amide) fiber , An antioxidant such as a hindered phenol compound or a phosphate compound, a releasing agent such as ethylene bis stearate, a polyethylene wax and a lubricant may be arbitrarily added But is not necessarily limited thereto.

Thus, according to the present invention, it is possible to produce a polyoxymethylene resin composition which retains mechanical properties while suppressing the formaldehyde emission as described above, and is inhibited from mold depreciation.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are for the purpose of illustrating the present invention more specifically, and the present invention is not limited thereto.

Examples 1 to 8

Based on 100 parts by weight of the polyoxymethylene resin, the content of each component was blended in the proportions shown in Table 1 below to prepare a polyoxymethylene resin composition.

Comparative Examples 1 to 10

Based on 100 parts by weight of the polyoxymethylene resin, the content of each component was blended in the proportions shown in Table 1 below to prepare a polyoxymethylene resin composition.

division
(Unit weight parts) (a) (b) (c) (d) Example 1 100 0.03 0.2 0.1 Example 2 100 0.03 0.2 0.2 Example 3 100 0.01 0.2 0.1 Example 4 100 0.2 0.2 0.1 Example 5 100 0.03 0.05 0.1 Example 6 100 0.03 0.5 0.1 Example 7 100 0.03 0.5 0.05 Example 8 100 0.03 0.5 0.5 Comparative Example 1 100 - - - Comparative Example 2 100 - 0.2 - Comparative Example 3 100 - 0.2 0.1 Comparative Example 4 100 0.03 0.2 - Comparative Example 5 100 0.3 0.2 0.1 Comparative Example 6 100 0.005 0.2 0.1 Comparative Example 7 100 0.03 0.55 0.1 Comparative Example 8 100 0.03 0.04 0.1 Comparative Example 9 100 0.03 0.2 0.04 Comparative Example 10 100 0.03 0.2 0.6 (a): polyoxymethylene resin (KOCETAL K300, Kolon Plastics)
(b): alkaline earth metal hydroxides (Rheinchemie, Ca (OH) ₂ )
(c): 1,12-dodecanedicarboxylic acid dihydrazide (Japan Finechem, N-12)
(d): zinc stearyl phosphate (Sakai chemical, LBT-1830)

<Measurement example>

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

- Tensile strength: measured according to ASTM D638 standard.

- Notch impact strength: Measured according to ASTM D256 standard.

- Formaldehyde emissions: Measured according to VDA 275 (German Automobile Manufacturers Association) standard. For the test specimens, square specimens of 100 mm × 40 mm × 2 mm were used. The test specimens were prepared by injection molding at 190 ° C and 220 ° C.

① In a polyethylene container, 50 ml of distilled water was put, and the test piece was kept in air-tight state at 60 ° C for 3 hours in the air.

② Remove the container and leave it at room temperature for 1 hour.

③ The distilled water in the polyethylene container was reacted using acetylacetone colorimetric method and the amount of formaldehyde absorbed was measured using UV Spectrometer.

- Point of Mold Deposition At the time of injection molding at a cylinder temperature of 240 ° C and a mold temperature of 40 ° C using an LG IDE-75EN hot runner injection molding machine at the time when mold attachment, that is, mold depozit, The shot was confirmed and evaluated.

Mold release amount (mold contamination degree): The mold surface was visually confirmed after 3,000 shot continuous molding in the same manner as when the mold defective point was measured, and evaluated by dividing into the following three categories.

O: Mold deflection is small and mold contamination is good.

Δ: Mold contamination due to mold deformation is serious.

X: There is a lot of mold depot formation, and the surface of the product is not formed.

division The tensile strength
(kgf / cm ₂ ) Notch
Impact strength
(kgcm / cm) Formaldehyde
Emission
190 ℃
(mg / kg) Formaldehyde
Emission
220 ℃
(mg / kg) Mold
DEPOSIT
When
(short) Mold
DEPOSIT
Generation Example 1 640 7.0 0.3 0.8 550 O Example 2 635 6.8 0.5 1.0 350 O Example 3 644 6.8 0.9 1.6 300 O Example 4 633 6.5 1.0 1.8 150 O Example 5 645 7.0 1.3 1.9 450 O Example 6 628 6.0 0.2 0.7 150 △ Example 7 625 6.1 0.3 0.8 150 △ Example 8 622 6.0 0.4 0.8 100 △ Comparative Example 1 645 6.8 8.2 17.8 1000 O Comparative Example 2 640 6.5 1.3 4.5 50 X Comparative Example 3 640 6.2 1.0 3.2 150 △ Comparative Example 4 642 7.0 1.5 6.6 50 X Comparative Example 5 630 6.0 2.1 7.3 50 X Comparative Example 6 637 6.9 1.2 3.8 150 △ Comparative Example 7 622 6.0 0.2 0.9 50 X Comparative Example 8 645 6.6 3.5 8.9 800 O Comparative Example 9 650 6.3 0.9 2.2 350 O Comparative Example 10 641 6.7 1.0 3.5 300 O

As a result of evaluation of the physical properties, as shown in Table 2, the polyoxymethylene resin compositions of Examples 1 to 8 had no significant difference in mechanical properties compared to the polyoxymethylene resin composition of Comparative Example 1, but the formaldehyde emission was remarkably decreased appear. However, the incidence of mold depreciation was increased by the additionally added additives as compared with Comparative Example 1. However, from the viewpoint of excellent reduction of formaldehyde, mold contamination as in Comparative Examples 2 to 7 It can be confirmed that there is no problem.

Compared with Comparative Examples 1 and 2, it was confirmed that the higher the content of the dihydrazide compound as the component (c), the higher the mold defor- mation formation. In comparison with Comparative Examples 2 and 3 (d ) &Lt; / RTI &gt; component of the zinc phosphate ester compound. However, in comparison with Example 1 and Comparative Example 3, it was confirmed that the component (d) exhibited better performance in the presence of the alkaline earth metal hydroxide (b), and as in Comparative Example 4, And the component (d) were present, it was confirmed that when the dihydrazide compound (c) was not added, the decrease in the amount of formaldehyde emission at a high temperature was reduced, and mold depreciation occurred frequently.

Further, when the component (b) is added in a small amount or an excessive amount as in the case of Comparative Examples 5 and 6, the amount of formaldehyde emission and the effect of reducing the mold depozit generation are not sufficient. It has been found that the addition of a small amount or an excessive amount of the component (d), as in Comparative Examples 9 and 10, also causes a decrease in formaldehyde emission It was confirmed that it was difficult to obtain a remarkable effect.

As a result, it was confirmed that when the three additives were mixed in an appropriate amount as in Examples 1 to 8, the formaldehyde emission and the mold depozit formation were effectively suppressed and the formaldehyde emission inhibition was effectively maintained even at a high temperature.

Claims (7)

Polyoxymethylene; And
0.01 to 0.2 parts by weight of an alkaline earth metal hydroxide, 0.05 to 0.5 parts by weight of a dihydrazide compound represented by the following formula (1), and a zinc phosphate ester compound represented by the following formula (2) or (3), based on 100 parts by weight of the polyoxymethylene 0.05 to 0.5 parts by weight of a polyoxymethylene resin composition:
[Chemical Formula 1]

(2)

(3)

In the formula (1), R ₁ is an alkyl group of C 4, C 8 or C 10

And R ₂ in formulas (2) and (3) is an alkyl group of C 16 to C ₂₄ .
The polyoxymethylene resin composition according to claim 1, wherein the polyoxymethylene has a melting point (T _m ) measured by differential scanning calorimetry (DSC) of 160 to 180 ° C.
The method of claim 1, wherein the alkaline earth metal hydroxide is at least one selected from the group consisting of calcium hydroxide, magnesium hydroxide, strontium hydroxide, and barium hydroxide. Polyoxymethylene resin composition.
The method according to claim 1, wherein the dihydrazide compound is selected from the group consisting of adipic acid dihydrazide, sebacic acid dihydrazide, 1,12-dodecanedicarboxylic acid dihydrazide (1 , 12-dodecanedicarboxylic acid dihydrazide, and isophthalic acid dihydrazide. The polyoxymethylene resin composition according to claim 1,

The method of claim 1, wherein the zinc phosphate ester compound is selected from the group consisting of zinc stearyl phosphate, zinc behenic phosphate, zinc arachidonic phosphate, zinc palmitic acid phosphate, phosphate, and mixtures thereof. The polyoxymethylene resin composition according to claim 1,
The polyoxymethylene resin composition according to claim 1, wherein the composition has a formaldehyde emission of 2.00 mg / kg or less at 220 DEG C as measured by VDA 275.
A polyoxymethylene resin molded article produced from the resin composition of any one of claims 1 to 6.