KR20180039361A - Polyoxymethylene Resin Composition and Molding Product Prepared By Using The Same - Google Patents

Abstract

The present invention relates to a polyoxymethylene resin composition, which comprises: polyoxymethylene; and, based on 100 parts by weight of the polyoxymethylene, 0.05 to 0.5 parts by weight of a calcium salt of a fatty acid, 0.01 to 1 parts by weight of a porous organic-inorganic hybrid silicate, and 0.01 to 0.2 parts by weight of a semi-aromatic polyamide, and to molded parts prepared therefrom. The present invention provides: polyoxymethylene resin composition, which generates less formaldehyde and decomposes less resin even after injection holding while maintaining physical properties such as excellent mechanical strength and impact resistance of a conventional polyoxymethylene resin; and the molded parts prepared therefrom.

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 and a molded article produced using the same.

BACKGROUND OF THE INVENTION Polyoxy methylene resins are high-performance plastics having a balance of mechanical strength and impact resistance, and have been used in a wide range of fields such as electronic equipment and automobile parts. However, polyoxy methylene resins are easily decomposed under acidic or alkaline conditions under a heating oxidizing atmosphere in the structure, and when they stay in an injection machine for a long time or exposed to hot water, various problems arise due to the decomposition of the resin.

Efforts have been made to improve the thermal stability of such polyoxymethylene by stabilizing chemically active terminals and adding heat resisting agents and formaldehyde scavenger to improve the thermal stability and the lack of hydrolysis. However, There has been a limit in improving formaldehyde gas generation or in the case of using hot water of an injection product to improve formaldehyde generation in water due to resin decomposition and deterioration of physical properties.

In order to improve the thermal stability of the polyoxymethylene resin, a polyoxymethylene stabilized with respect to oxidation and pyrolysis by containing a steric hindrance phenol, a fatty acid alkaline earth metal salt having 10 to 20 carbon atoms and / or a hydroxide of an alkaline earth metal, The resin composition is disclosed in Japanese Patent Publication No. 55-22508. By containing a steric hindrance phenol and a fatty acid alkaline earth metal salt having 22 to 36 carbon atoms in the polyoxymethylene resin, the resin composition is stabilized against oxidation and pyrolysis, The inhibited polyoxymethylene resin composition is disclosed in Japanese Patent Publication No. 60-56784.

JP-A-3-14857 discloses a combination of a hindered amine compound, a hindered phenol-based antioxidant having a molecular weight of 400 or more, and a carboxylic acid metal salt having 12 or more carbon atoms, in JP-A-62-45662, Japanese Patent Application Laid-Open No. 11-29692 discloses a combination of at least one member selected from the group consisting of a fatty acid, a phosphate, a carbon black, a quinoline compound, an amide compound and an amine compound A combination of heat stabilizers has been proposed.

Further, Japanese Patent Publication (Kokoku) No. 62-4422 discloses a polyoxymethylene resin composition comprising polyamide, a fatty acid having 12 to 35 carbon atoms, a fatty acid calcium salt having 12 to 35 carbon atoms, an aliphatic alcohol having 12 to 36 carbon atoms Discloses a polyoxy methylene resin composition which contains at least one of a group consisting of a magnesium salt and a magnesium salt and which has extremely few precipitates in the mold at the time of molding and is excellent in thermal stability. Japanese Patent Publication No. 62-58387 The publication discloses a polyoxymethylene (polyoxymethylene) resin having high thermal stability by containing a triazine compound substituted with an amine in a polyoxy methylene resin and a hydroxide, an acid salt, a carboxylic acid salt or an alkoxide of an alkali metal or an alkaline earth metal with a steric hindrance phenol polyoxy methylene) resin composition.

However, even if a polyoxy methylene resin composition having a proper combination of stabilizers and a stabilizer is mixed, even if a resin composition having a terminal or main chain of a polymer is subjected to action of heat or oxygen in a cylinder of a molding machine under severe conditions, It is difficult to completely prevent decomposition and generation of formaldehyde gas and to reduce decomposition of resin in hot water. In addition, discoloration occurs after aging at a high temperature for removing crystallization and stress after extrusion, and the product value is rather lost. Therefore, there is a strong demand for a molded and extruded product which is improved.

In relation to such a problem, Japanese Patent Application Laid-Open No. 2006-111874 discloses a hydrazide compound, an amine substituted triazine compound as a formaldehyde capturing agent, a hindered phenol compound as an antioxidant, an alkali metal having an alkali metal content of 50 ppm or less and an alkali It has been proposed to add metal compounds represented by the group consisting of hydroxides of organic metals, organic acid salts and inorganic acid salts. However, when a basic additive is added to inhibit acid decomposition by formic acid, it acts as an acid component neutralizing agent, but the hydrolysis of the end of the formic acid ester is promoted.

Accordingly, the present invention can provide a polyoxymethylene resin composition which is low in formaldehyde generation even after injection residence and has little decomposition of resin even in hot water, while retaining physical properties such as excellent mechanical strength and impact resistance of conventional polyoxymethylene resin To provide a molded article.

A first preferred embodiment of the present invention for solving the above problems is a polyoxymethylene; And 0.05 to 0.5 parts by weight of a fatty acid calcium salt, 0.01 to 1 part by weight of a porous organic-inorganic hybrid silicate and 0.01 to 0.2 part by weight of a semi-aromatic polyamide resin per 100 parts by weight of the polyoxymethylene. Oxymethylene resin composition.

Wherein the polyoxyethylene metilrenneun differential scanning calorimetry melting point (T _m) may be in the 160 to 180 ℃, calcium salts the fatty acid is measured by the measurement (DSC) is based on the total weight, calcium content according to one embodiment 5.7 to 6.7 By weight, and the content of free fatty acid is 1.0% by weight or less .

In addition, the porous organic-inorganic hybrid silicate according to the first embodiment may have a pore size of 50 nm or less and a surface area of 200 to 2000 m 2 / g, and the semi- melting point, measured by scanning calorimetry (DSC) may be in (T _m) is 280 to 330 ℃.

Further, the composition according to the first embodiment may have a weight loss of 0.2% or less after aging at 220 ° C for 30 minutes and a formaldehyde concentration in water of 10 ppm or less after immersion for 1 hour at 100 ° C.

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

INDUSTRIAL APPLICABILITY The polyoxymethylene resin composition according to the present invention is excellent in mechanical strength and impact resistance inherent in polyoxymethylene, has low occurrence of formaldehyde after injection residence, less decomposition of resin in hot water, As plastic, it can be easily applied to the interior and exterior materials of automobiles, precision electric and electronic products, household goods, and drinking water.

The present invention relates to a polyoxymethylene resin composition having less generation of formaldehyde even after injection residence and having improved water resistance, and more specifically, polyoxymethylene; And 0.05 to 0.5 parts by weight of a fatty acid calcium salt, 0.01 to 1 part by weight of a porous organic-inorganic hybrid silicate and 0.01 to 0.2 part by weight of a semi-aromatic polyamide resin per 100 parts by weight of the polyoxymethylene. To provide an oxymethylene resin composition, and to provide a molded product of the polyoxymethylene resin produced from the composition.

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. Here, the oxymethylene-based copolymer may contain 0.4 to 15 mol% of oxyethylene repeating units and 85 to 99.6 mol% of oxy-methylene repeating units based on the total mol of the polymer from the viewpoints of improving the thermal stability of the polymer and improving the crystallinity of the formability have.

Fatty acid calcium salt

In the present invention, the calcium salt of fatty acid preferably has a calcium content of 5.7 to 6.7% by weight based on the total weight of the fatty acid calcium salt and a content of free fatty acid such as stearic acid and 12-hydroxystearic acid of 1.0% The content thereof may be 0.05 to 0.5 parts by weight based on 100 parts by weight of the polyoxymethylene resin.

When the content of the fatty acid calcium salt is less than 0.05 part by weight, the unstable terminal of the polyoxymethylene can not be decomposed sufficiently, resulting in a source of formaldehyde gas in the subsequent injection. When the amount of the fatty acid calcium salt is more than 0.5 parts by weight, formaldehyde and formic acid ) And the like, thereby generating a polysaccharide, which may cause a problem of deterioration in appearance due to discoloration of the polymer.

Porous organic-inorganic hybrid Silicate

In the present invention, the porous organic-inorganic hybrid silicate improves the process stability through gas adsorption in the stabilization step, reduces decomposition of the resin by gas by reducing formaldehyde and formic acid generated in the molding, (1) to improve the thermal stability of the resin during processing to minimize the discoloration after aging for a long period of time after formation of formaldehyde gas or extrusion molding of the product and removal of stress .

[Chemical Formula 1]

In Chemical Formula 1, R is a chemical structure of Al ₂ Si ₂ O ₅ (OH) _X .My, wherein M is at least one element selected from the group consisting of P, Ca, Zn, Fe, K, , Ag, Mg, and Ti, x is an integer of 1 to 5, and y is an integer of 2 to 7.

The porous organic-inorganic hybrid silicate may be prepared by hydrolyzing 60 to 98% by weight of a silica precursor and 2 to 40% by weight of an organosilane in the presence of a surfactant, followed by dehydration and washing. The silica precursor may be at least one selected from the group consisting of an alkoxysilylalkylene having at least four alkoxy groups, a tetraalkylorthosilicate and an alkoxysilylalkane having at least four alkoxy groups, An alkoxy silane having an alkoxy group, an alkoxy silane silane, an alkoxy silane silane, and an alkoxyaralkyl silane.

The porous organic-inorganic hybrid silicate may have a pore size of 50 nm or less and a surface area of 200 to 2000 m 2 / g. Due to the pore size and surface area, VOCs having a formic acid and a hydroxy (-OH) It is possible to capture the same low-molecular substance and remove the substance causing the discoloration.

The content of the porous organic-inorganic hybrid silicate may be 0.001 to 1 part by weight based on 100 parts by weight of the polyoxymethylene resin. When the content of the porous organic-inorganic hybrid silicate is less than 0.001 part by weight, The adsorption of volatile organic compounds (VOCs) may be deteriorated. If the amount of the volatile organic compound (VOCs) is more than 1 part by weight, the polyoxymethylene resin may be decomposed by the metal contained in the porous organic / inorganic hybrid silicate, The bonding force between the short-term resin and the resin is weakened and decomposition occurs. As a result, the gas is released and foaming may occur, and the stability during the manufacturing process may be deteriorated.

Semi-Aromatic Polyamide

In the present invention, the semi-aromatic amide includes a component derived from a directional carboxylic acid (terephthalic acid, isophthalic acid) and a component derived from an aliphatic diamine, and can be measured by differential scanning calorimetry (DSC ) May be 90 to 180 ° C, more preferably 110 to 150 ° C. In the present invention, the semiaromatic polyamide has a very high thermal stability, thereby improving the discoloration that may occur during the stabilization process at a high temperature, stabilizing the formaldehyde capture and terminal by the amide group, The effect of improving the characteristics can be obtained.

The semi-aromatic polyamide is preferably contained in an amount of 0.01 to 0.2 part by weight based on 100 parts by weight of the polyoxymethylene. When the content is less than 0.01 part by weight, Formic acid ester group and the ability to capture formaldehyde are deteriorated. Formaldehyde generation in water is increased due to decomposition of resin during hot water deposition, and the amount of formaldehyde gas generated during molding is increased, and 0.2 If it is more than 100 parts by weight, it may react with gas generated in the stabilization process to cause discoloration, which may result in deterioration in appearance.

According to a preferred aspect of the invention, the semi-aromatic polyamide is a differential scanning calorimetry melting point as measured by the measurement (DSC) (T _m) is preferably from 280 to 330 ℃, and 290 to 330 ℃ in that mechanical strength and formability Which is more preferable. The glass transition temperature and melting point of the semiaromatic polyamide can be controlled by the dicarboxylic acid component unit constituting the semiaromatic polyamide, the kind of the aliphatic diamine component unit, or the molecular weight of the semiaromatic polyamide resin.

At this time, when a melting temperature (T _m) and a glass transition temperature (Tg) described in the present invention, a differential scanning calorimeter than that of (for example, DSC220C type, Seiko Instruments Co., Ltd.) as measured by specifically as follows: Or may be measured by a method. About 5 mg of the semi-aromatic polyamide is sealed in an aluminum pan for measurement and heated from room temperature to 330 占 폚 at 10 占 폚 / min. In order to completely melt the semi-aromatic polyamide, it is kept at 330 캜 for 5 minutes and then cooled to 30 캜 at 10 캜 / min. Then, after leaving at 30 DEG C for 5 minutes, the second heating is carried out at 10 DEG C / min to 330 DEG C. [ 2 as the melting point (T _m) of the peak temperature (℃) of the semi-aromatic polyamide in the second heating, and is referred to as a displacement point to the glass transition temperature (Tg) corresponding to the glass transition.

Examples of the resin that is particularly preferable as the semiaromatic polyamide in the present invention include dicarboxylic acid component units of terephthalic acid and isophthalic acid component units and aliphatic diamine component units of 1,6-diaminohexane and 2-methyl-1 , 5-pentadiamine; A resin wherein the dicarboxylic acid component unit is a terephthalic acid component unit and the aliphatic diamine component unit is 1,9-nonanediamine and 2-methyl-1,8-pentadiamine; A resin in which the dicarboxylic acid component unit is a terephthalic acid component unit and an isophthalic acid component unit, and the aliphatic diamine component unit is 1,6-diaminohexane, but the present invention is not limited thereto.

More specifically, the semiaromatic polyamide is PA12 / MACMI (PA12 / 3,3-dimethyl-4,4-diaminocyclohexylmethane, isophthalic acid), PA12 / MACMT , 4-diaminocyclohexylmethane, terephthalic acid), PA MACM 12 (3,3-dimethyl-4,4-diaminocyclohexylmethane, decanedicarboxylic acid or laurolactam), PA6T, PA6T / 66, PA6I / 6T and PA6I / 6T / MACMI, among which polyamide 6T / 6I may be more preferable.

Said semi-aromatic polyamide can be prepared by known methods, for example polycondensation of dicarboxylic acid and diamine in a homogeneous solution. More specifically, the dicarboxylic acid and the diamine are heated in the presence of a catalyst as described in WO03 / 085029 to obtain a lower condensate, and then a shear stress is applied to the melt of the lower condensate, Can be prepared by combining them.

To the composition of the present invention, antioxidants such as a releasing agent, a colorant, a nucleating agent, a plasticizer and a phosphate compound, a hindered amine compound, a benzophenone compound, a benzotriazole ( Such as a light stabilizer such as a benzotriazole based compound, a formaldehyde scavenger such as melamine, guanidine, Dicyan diamide, a lubricant, etc., But is not limited to.

As a result, according to the present invention, it is possible to provide a high-performance, balanced, high-performance plastic having excellent thermal stability and hydrolytic properties under high temperature melting conditions, less formaldehyde generation even after injection molding, less decomposition of resin even in hot water, A polyoxy methylene resin composition can be obtained. Further, it is possible to provide a polyoxymethylene resin molded article which can be easily manufactured and applied in the fields of interior and exterior materials for automobiles, precision electric and electronic products, household articles, and drinking water.

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.

Example  1 to 6

A polyoxy methylene resin composition was prepared by blending a fatty acid calcium salt, a porous organic-inorganic hybrid silicate and a Semi-Aromatic polyamide resin in a proportion shown in Table 1 to 100 parts by weight of a polyoxymethylene resin.

Comparative Example  1 to 6

A polyoxy methylene resin composition was prepared by blending a fatty acid calcium salt, a porous organic-inorganic hybrid silicate and a semi-Aromatic polyamide at a ratio shown in Table 1 with respect to 100 parts by weight of a polyoxymethylene resin.

division
(Unit: parts by weight) Polyoxymethylene Composition 1
OHC Composition 2
TS-1 Composition 3
PA 3426 Example 1 100 0.05 0.06 0.05 Example 2 100 0.5 0.06 0.05 Example 3 100 0.1 0.002 0.05 Example 4 100 0.1 One 0.05 Example 5 100 0.1 0.06 0.001 Example 6 100 0.1 0.06 0.2 Comparative Example 1 100 0.03 0.06 0.05 Comparative Example 2 100 0.8 0.06 0.05 Comparative Example 3 100 0.1 - 0.05 Comparative Example 4 100 0.1 1.5 0.05 Comparative Example 5 100 0.1 0.06 - Comparative Example 6 100 0.1 0.06 0.3 - Composition 1: 12-hydroxystearic acid (Sunace OHC)
- Composition 2: Porous organic-inorganic hybrid silicate (TS-1, Taesung Environmental Research Institute)
Composition 3: Semi-Aromatic Polyamide (DuPont Selar PA 3426)

Property evaluation

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.

- Chip Yellow Index (YI): The yellow index of the chip was measured using a color meter.

- Aging Weight Reduction: 10 g of polyoxymethylene resin (Chip) was weighed at 220 캜 for 30 minutes and then weighed.

- Formaldehyde (FA, Formaldehyde): Measured by the VDA 275 method

- Formaldehyde (FA, Formaldehyde): After the injection temperature was set to 195 ℃, the resin was filled in the injection machine and stayed for 10 minutes. Formaldehyde was measured by VDA 275 method.

- Formaldehyde (FA): 5 g of Chip is thoroughly immersed in 50 ml of distilled water, aged in an oven at 100 ° C for 1 hour, and then the amount of formaldehyde dissolved in distilled water is measured by ultraviolet light absorption according to the acetylacetone method Respectively.

division Chip YI  Weight loss after aging Psalm FA
(ppm) Staying FA
(ppm) Wet
FA (ppm) Example 1 -5.7 0.18 6.7 18.7 8.6 Example 2 -2.2 0.12 6.9 17.2 7.5 Example 3 -4.5 0.13 7.8 19.1 7.9 Example 4 -6.5 0.17 5.6 15.6 7.7 Example 5 -6.1 0.09 8.4 16.7 8.3 Example 6 -3.5 0.10 2.5 15.2 4.7 Comparative Example 1 -6.2 0.47 31.4 65.7 9.7 Comparative Example 2 4.8 0.11 6.5 25.6 8.4 Comparative Example 3 -5.6 0.14 15.6 27.3 9.2 Comparative Example 4 -6.3 0.16 22.8 45.1 14.8 Comparative Example 5 -5.9 0.17 11.6 17.9 20.4 Comparative Example 6 3.2 0.12 7.3 16.4 5.6

As shown in Table 2, as shown in Table 2, the polyoxymethylene resin composition of the examples had a weight loss after aging at 220 占 폚 for 30 minutes and a wet FA value of the sample FA and the chip 10 minutes after the injection sample were all small It is less likely to decompose resin under severe conditions, has low thermal stability, less formaldehyde, less increase in formation of formaldehyde after 10 minutes of injection, low wet formaldehyde and low decomposition of resin in hot water .

On the other hand, as in Comparative Example 1, when the amount of the fatty acid calcium salt is small, the chip YI and the wet FA are small, but the weight loss after aging and the sample FA, especially the sample FA after the retention, Over-abundance indicates that chip YI is discolored and the quality of the left coronary is poor. In addition, when the porous organic-inorganic hybrid silicate was not added as in Comparative Example 3, the specimen FA and the retentive FA were increased. On the other hand, even if the addition amount was large as in Comparative Example 4, It was found that the number of specimen FA and stay FA increased.

Further, when the addition of the Semi-Aromatic polyamide resin was not carried out as in Comparative Example 5, the wet FA increased, and when the addition amount was increased as in Comparative Example 6, the FA characteristic due to the reaction with various organic volatile materials improved , and the chip YI is increased, resulting in a problem of deterioration in appearance quality.

Claims (7)

Polyoxymethylene; And
0.05 to 0.5 part by weight of a calcium salt of a fatty acid, 0.01 to 1 part by weight of a porous organic-inorganic hybrid silicate represented by the following formula (1), 0.01 to 0.2 part by weight of a semi-aromatic polyamide (based on 100 parts by weight of polyoxymethylene) Wherein the polyoxyethylene resin composition is a polyoxyethylene resin composition.
[Chemical Formula 1]

In Chemical Formula 1, R is a chemical structure of Al ₂ Si ₂ O ₅ (OH) _X .My, wherein M is at least one element selected from the group consisting of P, Ca, Zn, Fe, K, , Ag, Mg, and Ti, x is an integer of 1 to 5, and y is an integer of 2 to 7.
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 polyoxymethylene resin composition according to claim 1, wherein the fatty acid calcium salt has a calcium content of 5.7 to 6.7% by weight and a free fatty acid content of 1.0% by weight or less based on the total weight.
The polyoxymethylene resin composition according to claim 1, wherein the porous organic-inorganic hybrid silicate has a pore size of 50 nm or less and a surface area of 200 to 2000 m 2 / g.
The polyoxymethylene resin composition according to claim 1, wherein the semi-aromatic polyamide has a melting point (T _m ) measured by differential scanning calorimetry (DSC) of 280 to 330 ° C.
The composition according to claim 1, wherein the composition has a weight loss of 0.2% or less after aging at 220 占 폚 for 30 minutes and a formaldehyde concentration in water of 10 ppm or less after immersion for 1 hour at 100 占 폚. Resin composition.
A polyoxymethylene resin molded article produced from the composition of any one of claims 1 to 6.