WO2013100706A1

WO2013100706A1 - Polyoxymethylene composition having excellent friction and abrasion resistance and exfoliation resistance and molded product made of same

Info

Publication number: WO2013100706A1
Application number: PCT/KR2012/011758
Authority: WO
Inventors: 박승진; 정충렬; 이주원
Original assignee: 한국엔지니어링플라스틱(주)
Priority date: 2011-12-29
Filing date: 2012-12-28
Publication date: 2013-07-04
Also published as: KR101420633B1; KR20130077235A

Abstract

The present invention relates to a silicon-containing polyoxymethylene composition comprising silicon rubber powder and a heat stabilizer, and being exfoliation resistant and excellent in thermal stability and friction and abrasion resistance. The present invention also relates to a molded product made of the composition. Provided are a polyoxymethylene resin composition comprising: 100 parts by weight of polyoxymethylene, 0.5 to 5.0 parts by weight of silicon rubber powder, and 0.05 to 0.5 parts by weight of styrene and maleic anhydride; and a molded product made of the composition. The polyoxymethylene resin composition of the present invention has excellent friction and abrasion resistance, exfoliation resistance and thermal stability, and the molded product made of such a polyoxymethylene resin composition is suitable for use in electrical, electronic or mechanical components or in medical instrument components requiring a high level of friction and abrasion resistance, for example, in a gear, bushing, roller, slide, etc.

Description

【Specification】

[Name of invention]

Polyoxymethylene composition excellent in abrasion resistance and peeling resistance, and molded article made therefrom

[Technology] ^'

The present invention relates to a polyoxymethylene composition containing a silicone rubber powder having no peeling and improved thermal stability and abrasion resistance, and a molded article made therefrom. More specifically, the present invention relates to a silicone-containing polyoxymethylene composition comprising a silicone rubber powder and a thermal stabilizer and having excellent thermal stability and abrasion resistance without delamination, and a molded article prepared therefrom.

Background Art

Polyoxymethylene is used extensively up to the mechanical properties, chemical resistance, and the like within the ^"resistance, dimensional stability, electrical properties superior automotive applications in household goods. In particular, polyoxymethylene resin is not only excellent in mechanical properties, but also known to be excellent in abrasion resistance, it is easy to find a case that is applied to the parts that require abrasion resistance, such as gears and bearings. However, as the industry develops, there is a higher demand for the general characteristics of the polyoxymethylene resin and the advancement of the friction wear resistance. In general, in order to improve the abrasion resistance of the polyoxymethylene resin, oils or lubricants that lower the surface tension of the polyoxymethylene resin and smooth the sliding property are used together. Specifically, silicone oil or silicone gum has been used in combination with polyoxymethylene resin as a frictional wear agent in order to improve the friction wear resistance of the polyoxymethylene resin. However, the polyoxymethylene resin composition containing such silicone oil or silicone gum as a friction anti-wear agent has insufficient compatibility with polyoxymethylene. In a high temperature compounding or injection process, the silicone oil or silicone gum included as an anti-friction wear agent is liquefied or agglomerated, and as a result, the polyoxymethylene resin and the anti-friction wear agent are phase-separated and peeling occurs on the surface of the molded article. . In order to solve this peeling problem, a method of increasing the melt index of the polyoxymethylene resin composition (lower viscosity) or using modified silicone to improve compatibility between silicone and polyoxymethylene is used. Has been. However, peeling problems still occur when a thin injection molding or a gate size is small and a shear rate is large. In addition, aluminosiloxane was used in combination with polyoxymethylene in order to improve the peeling resistance of the molded article, but the molded article prepared with such a blend also has peeling phenomenon on the surface. Therefore, there is a need for a polyoxymethylene resin composition used for producing a molded article that not only ensures friction resistance and wear resistance but also does not cause peeling problems.

[Detailed Description of the Invention]

[Technical problem]

The present invention is to provide a polyoxymethylene resin composition excellent in frictional wear resistance and peeling resistance of the molded article by one embodiment. In another aspect, the present invention is to provide a polyoxymethylene resin composition excellent in appearance and dimensional accuracy of the molded article. In addition, by another embodiment of the present invention to provide a high temperature compound ^{"^} or a polyoxymerylene resin composition that does not occur liquefaction or aggregation during the injection process. Furthermore, another embodiment of the present invention is to provide a polyoxymethylene resin composition with excellent processability when forming a molding. On the other hand, according to another embodiment of the present invention to provide a molded article made of a polyoxymethylene resin composition excellent in abrasion resistance, peeling resistance and / or § resistance.

Technical Solution

The present invention provides a polyoxymethylene resin composition comprising 100 parts by weight of polyoxymethylene, 0.5 to 5.0 parts by weight of silicone rubber powder and 0.05 to 0.5 parts by weight of styrene maleic anhydride.

The silicone rubber powder may be prepared by addition polymerization of silicone rubber.

In addition, the silicone rubber powder preferably has at least one functional group selected from the group consisting of vinyl groups and hydrate groups.

The styrene maleic anhydride may be used having the following formula.

(Wherein n is an integer of 6 to 8.) Meanwhile, the present invention relates to the polyoxymethylene number

The molded article is provided in electrical, electronics, automobiles, equipment

Rollers, bushings or slides.

Advantageous Effects

In the polyoxymethylene resin composition according to one embodiment of the present invention, liquefaction or aggregation of the silicone rubber powder does not occur in a high temperature process such as compounding and injection molding. Therefore, the molded article made of the polyoxymethylene resin composition ensures excellent frictional wear resistance, does not cause peeling of the molded article, and shows excellent durability. In addition, the appearance and dimensional accuracy of the molded article are improved.

Furthermore, the polyoxymethylene resin composition provided by the present invention is excellent in thermal stability, and a mold deposit generated by attaching formaldehyde gas and decomposition products to a mold during injection molding of a conventional silicone gum-containing polyoxymethylene composition. ) The occurrence is reduced. The molded article of the polyoxymethylene resin composition according to one embodiment of the present invention having such excellent wear resistance, peeling resistance, and thermal stability is used in residues, electronics, mechanical parts, or medical device parts that require high wear resistance. For example, it is suitable for use as gears, bushings, rollers, slides, and the like.

[Brief Description of Drawings]

1 is a photograph showing gas marks remaining on a mold surface when evaluating a mold deposit.

[Best form for implementation of the invention]

The polyoxymethylene resin composition provided in the present invention not only secures abrasion resistance of the polyoxymethylene resin composition by blending polyoxymethylene resin, silicone rubber powder and styrene maleic anhydride, but also in the conventional polyoxymethylene resin composition. Recognizing that excellent peeling resistance is achieved and the thermal stability is improved that the peeling problem such as does not occur, was completed based on this. The polyoxymethylene resin composition having excellent abrasion resistance, peeling resistance and thermal stability provided in the present invention includes polyoxymethylene resin, silicone rubber powder and styrene-maleic anhydride. As polyoxymethylene resin, any of those commonly used in the art The polyoxymethylene resin may be used, but is not particularly limited, for example, a homopolymer of a polyoxymethylene unit of Formula 1 or a copolymer in which a unit of Formula 1 and a unit of Formula 2 are randomly bonded. Can be. The polyoxymethylene polymer of the present invention is not particularly limited, but a number average molecular weight (Mn) in the range of 10,000 to 00,000 can be used.

[Formula 1]

-f-CH ₂ 0-) ~

[Formula 2]

-l- (cx _£ x ₂ ) ,. o-3-

¾ and ¾ in Formula 2 may be the same or different from each other, and each independently selected from the group consisting of hydrogen and dC ₄ alkyl group, but not all hydrogen, X is an integer of 2 to 6. The oxymethylene homopolymer can be prepared by polymerizing formaldehyde or cyclic oligomers thereof, ie trioxane. The oxymethylene copolymer in which the unit of Formula 1 and the unit of Formula 2 are combined may be obtained by random copolymerization of formaldehyde or a cyclic ligomer thereof with a cyclic ether or cyclic formal. As the copolymerization monomer used in the random copolymerization, the cyclic ether is not limited thereto, and examples thereof include ethylene oxide, propylene oxide, butylene oxide, and phenylene oxide.

In this case, the cyclic formal is not limited thereto, and for example, 1,3-dioxolane, diethylene glycol formal, 1,3-propanedi formal, 1,4-butanediol formal, 1, 3-dioxepanformal, 1,3, 6-trioxokancan etc. are mentioned. Preferably, one or two or more monomers selected from monomers such as ethylene oxide and 1,3-dioxolane 1,4-butanediol formal may be used. The monomer is added to trioxane or formaldehyde as the main monomer and random copolymerization using Lewis acid as a catalyst forms a oxymethylene co-polymer having a melting point of 15 C C or more and two or more bonding carbon atoms in the main chain. In addition, any anionic catalyst or cationic catalyst known in the art may be used as the polymerization catalyst used in the polymerization of the oxymethylene polymer. The polymerization catalyst may be halogen such as chlorine, bromide or iodine; Organic or inorganic acids such as alkyl or allylsulfonic acid, HC10 ₄ , HI0 ₄₎ derivatives of HCIO4, CPh ₃ C (I0 ₄ ) (Ph is phenyl), R ₃ SiHS0 _4, and the like; Metal halide compounds such as BF ₃ , SbF ₃ , SnCl ₄ , TiCl _4> FeCl ₃ , ZrCl ₄ , MoCl ₅ , and SiF ₄ ; BF ₃ '0H ₂ , BF ₃ ' 0Et ₂ (Et is ethyl), BF ₃ · 0Bu ₂ (Bu is butyl), BF ₃ -CH ₃ C00H ₍ BF ₃ 'PF ₅ · HF, BF3-IO-Hyde Complexes of metal halides such as roxiacetphenol Ph ₃ CSnCl ₅₎ Ph ₃ CBF _{4 (} Ph ₃ CSbCl ₆₎ ; metal esters such as carboxylate compounds of copper, zinc, cadmium, iron, cobalt, nickel; P ₂ 0 ₅ Metal oxides such as + S0 ₂ , P ₂ 0 ₅ + phosphate esters, and catalysts combining organic metals with metal halides, etc., preferably using a coordination compound of boron trifluoride. Preferably BF ₃ · 0Et ₂ and BF ₃ · 0Bu _2. The polymerization can be carried out in the form of bulk polymerization, suspension polymerization or solution polymerization, the reaction rate of which is between o ^° c and ioo ^° c. Range, preferably 2 (rc to 8 (rc.). On the other hand, as a deactivator for deactivating the remaining catalyst after polymerization A Lewis base material having a non-covalent electron pair may be used to form a complex salt with a catalyst. Examples of such deactivators include tertiary amines such as triethylamine, cyclic sulfur compounds such as thiophene, and triphenylphosphine. Phosphorus-based compounds can be used, and chain transfer agents in the polymerization reaction of polyoxymethylene. As an agent), alkyl substituted phenol, ethers or alkyl substituted formamide acetal may be used, and alkyl ether such as dimethicmethane may be particularly preferably used. The polyoxymethylene composition provided in the present invention comprises a silicone rubber powder as an antifriction wear agent. Conventional polyoxymethylene compositions have been used silicone oils or silicone gums as antifriction wear agents, but they are phase separated between polyoxymethylene and antifriction wear agents by liquefaction or agglomeration in the compounding and / or injection process using the polyoxymethylene composition. Is generated, which causes a problem in which a peeling phenomenon occurs in a molded article made of such a polyoxymethylene composition. Therefore, it is preferable to use an anti-friction wear agent that can prevent peeling while securing excellent anti-friction wear resistance equivalent to that of a conventional anti-friction wear agent, and it is preferable to use silicone rubber powder as such an anti-friction wear agent. desirable. Silicone oil and silicone gum is a silicone fluid, the physical properties of which are determined according to the chain length and are dissolved in a solvent. In contrast, the silicone rubber powder is a part of the polymer chain of silicone oil black silicone gum crosslinked by a crosslinking agent. Depending on the application, but has a complete powder form made of silicone rubber molecules only. Therefore, when the silicone rubber powder is blended into the polyoxymethylene composition, not only can it be physically uniformly dispersed, but also the heat resistance and chemical resistance are improved due to the increase in the bonding strength between the silicon molecules due to crosslinking, Since it is maintained, the frictional wear resistance can be improved. In addition, the silicone rubber powder does not dissolve in a solvent, unlike silicone oil and silicone gum. Therefore, liquefaction or agglomeration of the silicone rubber powder does not occur in the compounding and / or injection process using the polyoxymethylene composition containing the silicone rubber powder, thereby preventing phase separation between the polyoxymethylene and the silicone rubber powder. Therefore, peeling phenomenon can be prevented in the molded article manufactured from the polyoxymethylene composition containing three silicone rubber powders. In order to obtain the silicone rubber powder of the present invention, in the case of addition polymerization of the silicone rubber, a crosslinking catalyst such as platinum, a crosslinking agent of organic dienes, and additives such as polyoxyethylene lauryl ether may be used to increase the degree of crosslinking. The crosslinking catalyst is used to promote reaction start, and the crosslinking agent may be used as a linking agent that crosslinks the silicone rubber with the vinyl group of the silicone. On the other hand, the additives such as polyoxyethylene lauryl ether to help the dispersion of the crosslinking reaction silicon to facilitate the crosslinking reaction more smoothly! These additives may be suitably formulated in amounts generally used in the art and will not be described in detail. The silicone rubber powder may have at least one functional group selected from the group consisting of vinyl groups and hydrate groups, and the silicone rubber powder having such functional groups has a high degree of crosslinking and is more preferable for use in the present invention. In the polyoxymethylene composition provided in the present invention, the silicone rubber powder is blended in an amount of 0.5 to 5.0 parts by weight based on 100 parts by weight of the polyoxymethylene resin. If the content of the silicone rubber powder is less than 0.5 parts by weight, the friction wear resistance is not expressed, if the content of more than 5.0 parts by weight a sudden drop in physical properties occurs, the polyoxymethylene resin does not exhibit the function. Therefore, it is preferable to use silicone rubber powder in the content of the above range. Furthermore, it is preferable to use the silicone rubber powder having a particle size of l / ffli to 5 in terms of frictional wear resistance. ᅳ Preference is also given to blending styrene-maleic anhydride (SMA) with the acetaldehyde odor (F-odor) and / or mold deposit (M / D) remover in the polyoxymethylene composition. As the styrene-maleic anhydride, a compound having the structure of Formula 3 is used.

[Formula 3]

(Wherein n is an integer of 6 to 8.) The styrene-maleic anhydride of Formula 3 is cumene end-capped, its melting point is 115 ^° C to 130 ^° C. . The styrene-maleic anhydride helps to disperse the additives blended into the composition of the present invention including silicone rubber powder, and polyoxymethylene resin 100 in terms of thermal stability (injection retention thermal stability and mold deposit removal) when forming a molded article. It is preferable to mix | blend in 0.05-0.5 weight part with respect to a weight part. This can prevent F-odor and M / D generation during the molding process. The polyoxymethylene resin composition according to the present invention may optionally include any kind of additive that may be blended as needed in the art. Although not limited thereto, additives that may be added to the composition of the present invention include antioxidants, lubricants, fillers, colorants, reinforcing agents, light stabilizers, pigments and the like. Such additional components may be used in amounts that generally do not adversely affect the physical properties of the compositions of the present invention in the content ranges commonly used in the art. As the antioxidant, any one generally known in the art may be used, for example, 2,2'-methylenebis (4—methyl-6-t-butylphenol), nucleated methylene glycol-bissulfate ( 3,5-di-t-butyl-4-hydroxyhydrocinnamate),

Tetrakis [methylene (3,5-di-t-butyl-4-hydrocyhydrocinnamate)] methane,

Triethyleneglycol-bis-3- (3-t-butyl-4-hydroxytoxy-5-methylphenyl) propionate,

1, 3, 5-trimethyl ᅳ 2,4, 6-tris (3,5 ᅳ di-t-butyl-4-hydroxybenzyl) benzene, n_octadecyl-

3- (4'-hydroxy ᅳ 3 ', 5'-di-t-butylphenol) propionate, 4,4'-methylenebis (2,6-di-t-butylphenol), 4,4' -Butylidene-bis- (6-t-butyl-3-methyl-phenol), di-stearyl 3,5-di- _t -butyl-4 부틸 hydroxybenzylphosphate, 2-t-butyl-6 -(3-t-butyl-5-methyl-2-hydroxybenzyl) -4-methylphenylacrylate, 3, 9-bis 2- [3- (3-t-butyl-4'hydroxy-5- Methylphenyl) propionyloxy] -hindered phenols such as -1,1-dimethylethyl -2,4,8 and 10-tetraoxaspiro [5,5] undecane; And 4′acetoxy-2, 2,6,6-tetramethylpiperidine, 4-stearoyloxy— 2, 2, 6,6-tetramethylpiperidine, 4-acryrooxy-2, 2,6,6-tetramethylpiperidine, 4-methoxy-2,2,6, 6-tetramethylpiperidine, 4-benzoyloxy- 2,2, 6,6-tetramethylpiperidine, 4-cyclonucleooxy-2,2,6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine, 4'benzyloxy'2,2,6 ， 6 ᅳ tetramethylpiperidine ， 4-

(Phenylcarbamooxy) -2,2,6,6-tetramethylpiperidine, bis (2,2,6,6-tetramethyl-4-piperidyl) oxalate, bis (2,2, 6,6-Tetramethyl-4 ᅳ piperidyl) alonate, bis (2,2,6,6-tetramethyl-4-piperidyl) adipate, bis (2,2,6,6-tetramethyl- 4- piperidyl) separate, bis (1,2, 2, 6,6—pentamethyl-piperidyl) separate, bis (2,2,6,6-tetramethyl-4-piperidyl) Terephthalate, 1,2-bis (2,2,6,6-tetramethyl-4-piperidyloxy) ethane, bis (2,2,6,6-tetramethyl-4-piperidyl) nuxamethylene -1,6-dicarbamate bis (1'mityl-2,2,6,6-tetramethyl-4'piperidyl) adipate, tris (2,2,6,6-tetramethyl-4 ᅳ piperi Hindered amines, such as dill) benzene- 1,3,5- tricarboxylate, are mentioned. More preferably, triethylene glycol-bis-3- (3-t-butyl-4-hydroxy-5 ᅳ methylphenyl)-propionate, 1, 6-nucleic acid-di-bis-3 (3, 5 -Di-t_butyl— 4-hydroxy-phenyl) propionate and tetrakis [methylene (3,5-di-t-butyl _4 ᅳ) Hydroxyhydrocinnamate)] methane may be used, and even more preferably triethyleneglycolbisbis-3— (3-t-butyl-4-hydroxy-5-methylphenyl) -pro Cypionate can be used. The antioxidant may be used in an amount generally formulated in the art, and is not particularly limited. For example, 0.01 to 1.0 part by weight, preferably 0.1 to 0.5, based on 100 parts by weight of polyoxymethylene resin. It can mix | blend by weight part. As the lubricant, any one generally known in the art may be used, for example, bis-stearamide, wax and polyether glycid, and the like, and particularly preferably ethylene bis-stearamide is used. Can be. The amount of the lubricant may also be used in an amount generally formulated in the art, and is not particularly limited, but may be, for example, 0.01 to 1.0 parts by weight, preferably 0.05 to about 100 parts by weight of the polyoxymethylene resin. It may be blended at 0.5 parts by weight. The polyoxymethylene composition provided in the present invention may be formulated with any component using any conventional apparatus known in the art to be used for the formulation of the composition. Although not limited to this, it can mix | blend using a single screw extruder which has an ejector, a twin screw extruder which has a multistage discharge hole, or a 2-axis shaft paddle type continuous mixing extruder, etc., for example. For example, the polyoxymethylene composition may be prepared by mixing a mixture of polyoxymethylene, silicone rubber powder and styrene maleic anhydride under a range (160-250 ^° C.) above the melting temperature of polyoxymethylene and a reduced pressure of 150-400 torr. It is compounded by injection into a semi-barrel type extruder or a two-axis rotor mixer, and is obtained by engraving and cutting (pelting). In this case, the pellet may be dried as necessary. The drying is not limited thereby, but for example, from about 2 hours to about 80 ~ 100 ^° C temperature range It can be performed for 4 hours. If the compounding and drying conditions are out of the above range, the unstable ends of the polyoxymethylene may be increased, thereby degrading the thermal stability of the polyoxymethylene. A molded article can be obtained using the polyoxymethylene composition as described above. The molded article may be manufactured by any molded article manufacturing method known in the art using the polyoxymethylene composition provided in the present invention. The molded article made of the polyoxymethylene composition has excellent friction resistance, abrasion resistance, peeling resistance, appearance and dimensional accuracy, and can be used in parts, devices, and the like, which require such physical properties. Although not limited to this, for example, it can be used in various gears, lorries, bushings, slides, etc. in the field of electrical, electronics, automobiles, machinery, medical devices.

[Form for implementation of invention]

Hereinafter, the present invention will be described in more detail with reference to Examples. The following examples illustrate the invention but do not limit the invention. EXAMPLE

Polyoxymethylene (KEPITAL F25-03HX as POM resin in Table 1), abrasion resistance, F—odor and M / D styrene-maleic anhydride (Atochem SMA 3000P) (represented as SMA in Table 1) After mixing the contents as shown in Table 1, using a twin screw extruder, melt-stirred at a screw speed of 340 rpm and a discharge amount of 350 kg / hr at a temperature of 170 to 230 ^° C., and cooling the melt from the extruder die through a cooling bath. It was prepared in the form of pellets.

Thus prepared polyoxamethylene composition using an injection machine at a temperature of 170 ~ 210 ^° C to prepare an injection test piece. Further 0.2 phr of antioxidant (Songnox 1010) was added.

Table 1

The material used in the present Example is as follows.

POM: KEPITAL F25-03H (MI = 13.0 g / 10min) (made by Korea Engineering Plastics Co., Ltd.)

Abrasion Resistant: Silicone Oil (CROMPTON L45 / 12500)

Silicon sword ： Sea Dragon Silicon HR-N

Silicone Rubber Powder: Dow-corning EP-5500

Alumino-siloxane: Silochem SC-101-a

F-Odor & M / D Remover: ATOCHEM SMA 3000P (Mw 9500)

Antioxidant: Quality Evaluation of S0NGN0X 1010 Molded Parts

The frictional wear resistance, peeling strength, tensile strength, elongation, Charpy laminar strength, thermal stability, and mold deposits were evaluated for the molded articles prepared by the respective inventive examples and comparative examples, and the results are shown in Table 2. It was. . The quality evaluation for each evaluation item was as follows.

(1) Friction and wear resistance (Ring-On-Ring Type-Resin)

Through-molded test specimens having an outer diameter of 25.6 mm, an inner diameter of 20 mm and a height of 15 mm were injection molded and fixed in a test apparatus, and tested under driving conditions of a pressure load of 6.6 kgf and a linear velocity of 10 cm / s. At this time, the test was carried out for 2 hours.

The frictional friction coefficient and the non-wear amount were calculated using the following equation to evaluate the frictional wear resistance. Dynamic Friction Coefficient = [Friction (kgf) X 10 cm)] / [Pressure Load (kgf) X 1.14 cm] Specific Wear = Wear Weight (mg) / [Density (mg / 醒³ ) X Pressurized Load (kgf) X Travel Distance (km)] * Test Equipment: Trust Type Friction Wear Tester The smaller the coefficient of dynamic friction and the specific wear obtained, the better the wear resistance. 2 (2) Peeling rate

Peeling occurred using a gear mold with a 3-pin-gate gate with a gate diameter of about 0.8 難 and a general injection machine.The injection pressure was 800kgf / cm ² , and the injection speed was 10cm / s ᅳ 20cm / s, It was adjusted in the order of 30cm / s, 40cm / s to confirm the presence of peeling of the surface of the molded article. Peeling incidence was evaluated by injection molding a gear having a 3-pin-gate gate for each injection speed, and according to the injection speed at which peeling occurred on the surface thereof. When the evaluation criterion value is 0, no peeling occurs, and the smaller the value, the smaller the peeling degree.

0: No peeling occurred at all regardless of the injection speed. 1: Peeling occurs at the injection speed of 45 to 200 mm / s.

2: Peeling occurred at injection speed 35 ~ 45 薩 / s.

3: Peeling occurs at the injection speed of 25 to 35 kPa / s.

4: Peeling occurred at the injection speed of 15 to 25 kPa / s.

5: Peeling generate | occur | produced at the injection speed of 15 kPa / s or less.

(3) tensile strength and elongation

Tensile strength and elongation were measured according to the ISO 527 method.

Higher values mean higher tensile strength and elongation oj, and lower values mean lower tensile strength and elongation.

(4) Charpy impact strength

Charpy laminar strength was measured according to the ISO 179 method. If this value is high, the Charpy laminar strength is high. If the value is low, the Charpy laminar strength is low.

(5) Thermal Stability (Thermal Stability Measurement according to VDA275 Method)

A molded article of size 100 mm × 40 mm × 2 mm was fixed in a 1 L bottle containing 50 ml of water so as not to contact with water and then sealed. After leaving the bottle equipped with 6 (C for 3 hours, the amount of C¾0 collected in water was analyzed by UV spectrophotometer to measure the amount of CH ₂ 0 generation of the molded product.

Lower values indicate better thermal stability.

(6) Mold Deposit

The mold deposit is a gas that remains on the mold surface on the side of the moving shaft after 300 consecutive injection moldings in a leaf-shaped mold at a resin temperature of 20 (rC to 220 ^° C and a mold temperature of 70 ^° C) using a small injection molding machine. The marks were visually evaluated and evaluated, etc. The gas marks remaining in the leaf-shaped molds were attached to Fig. 1 and evaluated to 1 to 5 depending on the degree of gas marks to the extent shown in Fig. 1.

1 shows the lowest thermal stability with the lowest mold deposit. Table 2

As can be seen from the above table, the molded article of the invention example prepared from the polyoxymethylene resin composition provided in the present invention achieves at least the friction wear resistance equivalent to that of the molded article of the comparative example, not only shows excellent peeling resistance, but also injection molding Significantly improves the degree of F-odor and M / D generation at the time of use, and is suitable for use in parts and / or devices requiring heat stability, abrasion resistance, and peeling resistance.

Claims

[Range of request]

[Claim 1]

Polyoxymethylene resin composition comprising 100 parts by weight of polyoxymethylene, 0.5 to 5.0 parts by weight of silicone rubber powder, and 0.05 to 0.5 parts by weight of styrene maleic anhydride.

[Claim 2]

The polyoxymethylene resin composition according to claim 1, wherein the silicone rubber powder is obtained by addition polymerization of silicone rubber.

[Claim 3]

The polyoxymethylene resin composition of claim 1, wherein the silicone rubber powder has at least one functional group selected from the group consisting of vinyl groups and hydrate groups.

[Claim 4]

The polyoxymethylene resin composition according to claim 1, wherein the styrene maleic anhydride is represented by the following formula (1).

(Wherein n is an integer of 6 to 8) [claim 5]

The molded article manufactured from the polyoxymethylene resin composition of any one of Claims 1-4. [Claim 6] The molded article according to claim 6, wherein the molded article is a gear, an lorler, a bushing, or a slide in an electric, electronic, automotive, mechanical or medical field.