WO2012046912A1

WO2012046912A1 - Novel compound for antioxidant and polyacetal resin composition including the same

Info

Publication number: WO2012046912A1
Application number: PCT/KR2010/008195
Authority: WO
Inventors: Dong-Kyung Park; Young-Ki Cho; A-Reum Lee; Daisuke Kobayashi
Original assignee: Songwon Industrial Co., Ltd
Priority date: 2010-10-07
Filing date: 2010-11-19
Publication date: 2012-04-12
Also published as: KR101136530B1

Abstract

Disclosed is an antioxidant represented by the Chemical Formula 1 or Chemical Formula 2.

Description

NOVEL COMPOUND FOR ANTIOXIDANT AND POLYACETAL RESIN COMPOSITION INCLUDING THE SAME

This application claims priority to and the benefit of Korean Patent Application No. 10-2010-0097826 filed in the Korean Intellectual Property Office on October 7, 2010, the entire contents of which are incorporated herein by reference.

The present invention relates to a novel compound for an antioxidant and a polyacetal resin composition including the same.

Generally, an acetal resin is an engineering resin having uniform mechanical properties, fatigue resistance, friction resistance, chemical resistance, size stability, and an excellent molding property, and it has been applied to the various fields such automobile parts, electro-electronic device parts, precision mechanical parts, medical parts, and the like.

However, the quality of polyacetal resin is required to be high in consideration of enlarging and varying the application field, so it has been suggested that various kinds of additives could be added to improve the properties while maintaining the inherit characteristics of the resin compositions.

In spite of the merits, the polyacetal resin has drawbacks of insufficient thermal stability, and it is easily decomposed by thermal impact, mechanical impact, or additives during a molding process. Particularly, it is easily decomposed by overheating due to insufficient thermal stability, so as to emit formaldehyde gas which is a toxic monomer. It may deteriorate the thermal resistance and may corrode metallic parts in the molding assembly or it may be discolored by attaching an organic compound. In addition, contamination of the working environment during the assembling process or of the environment while using the final product may occur. In addition, it has weak extraction resistance to a solvent and insufficient thermal stability.

In order to improve the properties of a polyacetal resin, several proposals have been suggested. One of them is to add an additive such as a steric hindrance phenol compound or the like. However, extraction resistance to the solvent and thermal stability are still insufficient even if providing a steric hindrance phenol compound.

Accordingly, it has been required to develop an antioxidant having both thermal stability and extraction resistance to be applied to the polyacetal.

One aspect of the present invention provides a novel compound for an antioxidant.

Another aspect of the present invention provides a polyacetal resin composition including a polyacetal resin and an antioxidant of a specific compound.

Yet another aspect of the present invention provides a molded product produced using the polyacetal resin composition.

According to one aspect of the present invention, an antioxidant including a compound represented by the following Chemical Formula 1 or Chemical Formula 2 is provided.

[Chemical Formula 1]

In the above Chemical Formula 1, R' and R" are independently a C1-C4 alkyl group, and n is an integer ranging from 1 to 3.

[Chemical Formula 2]

In the above Chemical Formula 2,

R is

,

R"' is a C1-C4 alkyl group, and

n is an integer ranging from 1 to 3.

In one embodiment of the present invention, the antioxidant may be N,N'-triethylenedioxy-bis-(3-tert-butyl-4-hydroxy-5-methylhydrocinnamamide).

In another embodiment of the present invention, the antioxidant may be N,N',N"-tris[(3-tert-butyl-4-hydroxy-5-methylphenyl)-propinonyl-3-oxa-pentyl]melamine.

According to another aspect of the present invention, a polyacetal resin composition including a polyacetal resin and an antioxidant of a compound represented by the following Chemical Formula 1 or Chemical Formula 2 is provided.

[Chemical Formula 1]

[Chemical Formula 2]

In the above Chemical Formula 2,

R is

,

R"' is a C1-C4 alkyl group, and

n is an integer ranging from 1 to 3.

The polyacetal resin composition may include 0.1 to 3.0 parts by weight of an antioxidant based on 100 parts by weight of the polyacetal resin.

The polyacetal resin may have a weight average molecular weight of 100,000 to 250,000.

The poly acetal resin composition may further include at least one of additive selected from a filler, a reinforcing agent, a nucleating agent, a plasticizer, a conductive agent, a release agent, an antioxidant, a light stabilizer, and a lubricant.

According to yet another aspect of the present invention, a molded product produced using the polyacetal resin composition is provided.

The molded product may be used in, for example, automobile parts such as an automobile fuel tank, a gear, a lever part, or the like.

The antioxidant according to the present invention is included in the polyacetal resin composition so it may decrease formaldehyde gas generation and improve thermal stability and extraction resistance to the solvent.

FIG. 1 is an FT-IR (Fourier transform infrared) graph of N,N'-triethylenedioxy-bis-(3-tert-butyl-4-hydroxy-5-methylhydrocinnamamide).

FIG. 2 is an FT-IR (Fourier transform infrared) graph of N,N',N"-tris[(3-tert-butyl-4-hydroxy-5-methylphenyl)-propinonyl-3-oxa-pentyl]melamine.

FIG. 3 shows ¹H NMR of N,N'-triethylenedioxy-bis-(3-tert-butyl-4-hydroxy-5-methylhydrocinnamamide).

FIG. 4 shows ¹H NMR of N,N',N"-tris[(3-tert-butyl-4-hydroxy-5-methylphenyl)-propinonyl-3-oxa-pentyl]melamine.

FIG. 5 is a graph showing the length maintenance for determining how a specimen is elongated during heat aging when the polyacetal resin specimen including the antioxidant compound according to one embodiment and another polyacetal resin specimen including another antioxidant compound are stored in a hot-air drier at 140℃.

FIG. 6 is a graph showing extraction resistance to the solvent of the specimen prepared from the polyacetal resin including the antioxidant compound according to one embodiment and the specimen prepared from another polyacetal resin including other antioxidant.

Hereinafter, the present invention is described in more detail.

One embodiment of the present invention provides an antioxidant represented by the following Chemical Formula 1 or Chemical Formula 2.

[Chemical Formula 1]

[Chemical Formula 2]

In the above Chemical Formula 2,

R is

,

R"' is a C1-C4 alkyl group, and

n is an integer ranging from 1 to 3.

The antioxidant represented by the above Chemical Formula 1 or Chemical Formula 2 may be used in a polyacetal resin composition.

The polyacetal resin composition includes a polyacetal resin and an antioxidant represented by the following Chemical Formula 1 or Chemical Formula 2.

[Chemical Formula 1]

[Chemical Formula 2]

In the above Chemical Formula 1,

R is

,

R"' is a C1-C4 alkyl group, and

n is an integer ranging from 1 to 3.

The polyacetal resin also refers to polyoxymethylene (POM), which is a polymer of formaldehyde or trioxain having a main chain of an acetal bond, and it may include a homopolymer, a copolymer, or a mixture thereof. In addition, the polyacetal resin may be branched or linear, and preferably it may have a weight average molecular weight of about 100,000 to 250,000.

As the polyacetal resin includes an antioxidant of the compound represented by Chemical Formula 1 or Chemical Formula 2, it may effectively provide characteristics such as formaldehyde gas generation reduction, excellent thermal stability, an extraction resistance to the solvent. Particularly, it also has merits of providing both compatibility to the polyacetal resin and extraction resistance to the solvent. In addition, as the compounds represented by Chemical Formula 1 and Chemical Formula 2 and the polyacetal resin form a hydrogen bond, the extraction resistance to the solvent is further enhanced.

The compound represented by Chemical Formula 1 or Chemical Formula 2 may be included in an amount as long as it acts as an antioxidant and it does not inhibit the overall physical characteristics of polyacetal resin composition.

According to one embodiment, the polyacetal resin composition may include about 100 parts by weight of polyacetal resin and about 0.1 to about 3.0 parts by weight of the antioxidant represented by Chemical Formula 1 or Chemical Formula 2. When the antioxidant represented by Chemical Formula 1 or Chemical Formula 2 is included within the range, it may improve the overall heat resistance of the polyacetal resin and prevent extraction as a white powder on the surface of the polyacetal resin after being molded. Preferably, the antioxidant represented by Chemical Formula 1 or Chemical Formula 2 may be included at about 0.2 to about 2.0 parts by weight based on 100 parts by weight of the polyacetal resin.

The polyacetal resin composition may further include an additive such as a filler, a reinforcing agent, a nucleating agent, a plasticizer, a conductive agent, a release agent, an antioxidant, a light stabilizer, a lubricant, or at least one associate thereof.

The polyacetal resin composition may be obtained by a known method. For example, the components and other additives may be simultaneously mixed and then melt-extruded in an extruder to provide a pellet.

The composition according to one embodiment may be molded for various kinds of products, for example, automobile parts such as an automobile fuel tank, a gear, a lever part, or the like.

Hereinafter, the embodiments are illustrated in more detail with reference to examples. However, the following are exemplary embodiments and are not limiting.

Examples

Preparation Example 1: Synthesis of N,N'-triethylenedioxy-bis-(3-tert-butyl-4-hydroxy-5-methylhydrocinnamamide)

A methyl 3-tert-butyl-4-hydroxy-5-methylphenylpropionate (177g, 0.707mol) is introduced into a 1L four-neck round flask and added with (ethylenedioxy)diethylamine (50g, 0.337mol) and heated. It is reacted under a nitrogen atmosphere for 9 hours with the temperature increased to 170℃, and the temperature is lowered to 70℃ after completing the reaction. 591 g of ethylacetate is added and the reactant is dissolved. It is moved into a 2L four-neck round flask and cooled to 50℃ and added with 295 g of hexane. It is cooled to 5℃ to be crystallized. The crystallized product is filtered and washed using 394g of petroleum ether. It is dried to provide 177 g of primary product in a yield of 89%.

150g of the obtained product is introduced into a 1L four-neck round flask and heated. The product is melted at 130℃ and then cooled. Then 300g of ethylacetate is added at 100℃ and agitated. 225g of hexane is introduced at 65℃, and is cooled to 5℃ to be crystallized. The crystallized product is filtered and washed using 394 g of petroleum ether. It is dried to provide 143 g of N,N'-triethylenedioxy-bis-(3-tert-butyl-4-hydroxy-5-methylhydrocinnamamide) in a yield of 95%.

[Chemical Formula 3]

N,N'-triethylenedioxy-bis-(3-tert-butyl-4-hydroxy-5-methylhydrocinnamamide)

FIG. 1 is a FT-IR (Fourier transform infrared) graph of N,N'-triethylenedioxy-bis-(3-tert-butyl-4-hydroxy-5-methylhydrocinnamamide) prepared in Preparation Example 1 (measurement apparatus: Biorad, FTS-40A).

FIG. 3 shows ¹H NMR of N,N'-triethylenedioxy-bis-(3-tert-butyl-4-hydroxy-5-methylhydrocinnamamide) prepared in Preparation Example 1.

Preparation Example 2: Synthesis of N,N',N"-tris[(3-tert-butyl-4-hydroxy-5-methylphenyl)-propinonyl-3-oxa-pentyl]melamine

Cyanuric chloride (53.7 g, 0.2912 mol), 1,4-dioxane (565 g), and potassium carbonate (77.9 g, 0.5636 mol) are introduced into a 1L four-neck round-bottomed flask. Diglycol amine (102.3 g, 0.9730 mol) is input into a dropping funnel at room temperature and introduced thereto at a temperature of 45℃ or below in a drop-wise fashion. After the introduction in a drop-wise fashion, it is heated to 96℃ and reacted under a nitrogen atmosphere for 5 hours. After completing the reaction, it is cooled to 90℃ and heat-filtered. The filtrate is distillated under the conditions of 50 mbar and 140℃ to remove the solvent, and it is evaporated under the same conditions to remove the raw material of diglycol amine. After completing the evaporation, it is cooled to 120℃ and added with 103 g of toluene and mounted with an oil-water separator, and then it is refluxed for 2 hours to remove remaining water. After completing the water removal, the solvent is distillated under the conditions of 50 mbar, 160℃ to provide an intermediate of 2-(2-{4,6-bis-[2-(2-hydroxy-ethoxy)-ethylamino]-[1,3,5]triazine-2-ilamino}-ethoxy)-ethanol in a yield of 87% (99.3g).

50.4 g of xylene and 0.4 g of Ti(OiPr)4 are added to 99.3 g (0.2543 mol) of the intermediate and heated. Methyl 3-tert-butyl-4-hydroxy-5-methylphenylpropionate (126 g, 0.8010 mol) is dripped thereto for two hours and heated up to 150℃. After the dripping, it is reacted at 150℃ for 14 hours. After completing the reaction, 300 g of toluene and 120 g of water are added and refluxed for 1 hour to separate water. The solvent is removed and added with 540 g of methanol and 10 g of diatomite, and heat-filtered at 60℃. After the heat-filtration, methanol is removed by distillation, and excessive methyl 3-tert-butyl-4-hydroxy-5-methylphenylpropionate is removed through a thin layer distiller under the conditions of 190℃ and 1 mbar. The reactant from which the solvent is removed is added with 1000 g of xylene to perform layer separation, and then the solvent is removed from the product. It provides 178.2 g of N,N',N"-tris[(3-tert-butyl-4-hydroxy-5-methylphenyl)-propinonyl-3-oxa-pentyl] melamine in a yield of 80%.

[Chemical Formula 4]

In the above Chemical Formula 4, R is

.

N,N',N"-tris[(3-tert-butyl-4-hydroxy-5-methylphenyl)-propinonyl-3-oxa-pentyl]melamine

FIG. 2 is an FT-IR (Fourier transform infrared) graph of N,N',N"-tris[(3-tert-butyl-4-hydroxy-5-methylphenyl)-propinonyl-3-oxa-pentyl]melamine prepared in Preparation Example 2 (measurement apparatus: Biorad, FTS-40A).

FIG. 4 shows ¹H NMR of N,N',N"-tris[(3-tert-butyl-4-hydroxy-5-methylphenyl)-propinonyl-3-oxa-pentyl]melamine prepared in Preparation Example 2.

Example 1

0.3 parts by weight of the compound obtained from Preparation Example 1 and 0.1 parts by weight of melamine are mixed into 100 parts by weight of polyacetal resin to provide a composition, and the composition is fused and knead-extruded to provide a pellet. It is extruded by a φ30 twin-screw extruder.

Example 2

A specimen is prepared in accordance with the same procedure as in Example 1, except that the compound obtained from Preparation Example 2 is used instead of the compound obtained from Preparation Example 1.

Comparative Example 1

A specimen is prepared in accordance with the same procedure as in Example 1, except that triethyleneglycol-bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate represented by the following Chemical Formula 5 is used instead of the compound obtained from Preparation Example 1.

[Chemical Formula 5]

Triethyleneglycol-bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate

Comparative Example 2

A specimen is prepared in accordance with the same procedure as in Example 1, except that N,N'-hexamethylene-bis-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate represented by the following Chemical Formula 6 is used instead of the compound obtained from Preparation Example 1.

[Chemical Formula 6]

N,N'-hexamethylene-bis-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate

First, the compound obtained from Preparation Example 1, the compound obtained from Preparation Example 2, the compound represented by Chemical Formula 5, and the compound represented by Chemical Formula 6, which are used in Examples 1 and 2 and Comparative Examples 1 and 2, respectively, are measured for thermal decomposition characteristics (TGA) according to thermogravimetric analysis/differential thermal analysis (measurement apparatus: TA Instruments, TA-2100). The results are shown in the following Table 1.

Table 1

Weight loss(%)	Compound synthesized in Preparation Example 1	Compound synthesized in Preparation Example 2	Compound represented by Chemical Formula 5	Compound represented by Chemical Formula 6
5wt%	331℃	325℃	298℃	330℃
10wt%	355℃	342℃	316℃	343℃
50wt%
	400℃	387℃	362℃	404℃

In addition, the specimens obtained from Examples 1 to 2 and Comparative Examples 1 to 2 are measured for extrusion performance, length maintenance showing how the specimen is elongated during heat aging, and extraction resistance to the solvent in accordance with the following method.

- Evaluation of extrusion performance

The extrusion performance is evaluated by whether the decomposition gas is generated during the extrusion, whether the color is changed, and how the viscosity is decreased. "Good" in the extrusion performance indicates that the decomposition gas is less generated, the color is less changed, and the viscosity is less decreased than those of Comparative Example 1.

PCM30 （IKEGAI, LTD.）Cylinder temp.:　(Hopper) 180℃-240℃-240℃-230℃ (Die）Screw speed: 100rpm, Vacuum: -600mmHg, Output: 3kg/hr

The results are shown in the following Table 2.

Table 2

Antioxidant	Extrusionperformance	MI (g/10min)
Comparative Example 1	Comparison base	9.7
Comparative Example 2	good	9.5
Example 1	good	10.0
Example 2	good	12.7

- The specimen is stored in a hot-air drier at 140℃ for a predetermined time and measured for a tension test by a STROGRAPH AP Ⅱ (Toyo Seiki Seisaku-syo, LTD.). FIG. 5 is a graph showing specimen length maintenance showing how the specimen is elongated during the heat aging. As shown in FIG. 5, it is understood that the specimen obtained from Example 1 has excellent length maintenance during the heat aging.

- The extraction resistance to the solvent is measured by dipping 10 g of each specimen obtained from Example 1 and Comparative Examples 1 to 3 in 50 ml of CHCl₃ solvent at 90℃ for 6 hours and weighing the loss between before the extraction and after the extraction at 245℃ for 2 hours. FIG. 6 is a graph showing the results.

It is confirmed that both Examples 1 and 2 have excellent extraction resistance compared to Comparative Examples 1 and 2.

As shown in FIG. 5 and FIG. 6, it is understood that Example 1 has a superior tension characteristic to Example 2, but Example 2 has superior extraction resistance to Example 1. However, both Example 1 and Example 2 have sufficient characteristics within the desirable ranges, so they may include the same by selecting the antioxidant in a required kind and amount.

While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

An antioxidant comprising a compound represented by the following Chemical Formula 1 or Chemical Formula 2:

[Chemical Formula 1]

wherein, in the above Chemical Formula 1, R' and R" are independently a C1-C4 alkyl group, and n is an integer ranging from 1 to 3;

[Chemical Formula 2]

wherein, in the above Chemical Formula 2,

R is
,

R"' is a C1-C4 alkyl group, and

n is an integer ranging from 1 to 3.
The antioxidant of claim 1, which is N,N'-triethylenedioxy-bis-(3-tert-butyl-4-hydroxy-5-methylhydrocinnamamide) or N,N',N"-tris[(3-tert-butyl-4-hydroxy-5-methylphenyl)-propinonyl-3-oxa-pentyl]melamine.
A polyacetal resin composition comprising:

a polyacetal resin; and

an antioxidant represented by the following Chemical Formula 1 or Chemical Formula 2:

[Chemical Formula 1]

wherein, in the above Chemical Formula 1, R' and R" are independently a C1-C4 alkyl group, and n is an integer ranging from 1 to 3;

[Chemical Formula 2]

wherein, in the above Chemical Formula 2,

R is
,

R"' is a C1-C4 alkyl group, and

n is an integer ranging from 1 to 3.
The polyacetal resin composition of claim 3, which comprises 0.1 to 3.0 parts by weight of an antioxidant based on 100 parts by weight of the polyacetal resin composition.
The polyacetal resin composition of claim 3, wherein the polyacetal resin has a weight average molecular weight of 100,000 to 250,000.
The polyacetal resin composition of claim 3, wherein the polyacetal resin composition further comprises at least one additive selected from a filler, a reinforcing agent, a nucleating agent, a plasticizer, a conductive agent, a release agent, an antioxidant, a light stabilizer, and a lubricant.
A molded product produced using the polyacetal resin composition of any one of claim 3 to claim 6.
The molded product of claim 7, which is used in automobile parts.