WO2021029589A1 - Thermoplastic copolymer composition and molded product manufactured therefrom - Google Patents

Abstract

The present invention provides a thermoplastic copolymer composition used in the manufacture of a molded product such as a constant velocity joint boot of a vehicle, and thus can improve low-noise characteristics without deterioration of mechanical properties, wherein the composition comprises: a polyester elastomer; an additive comprising silica and a siloxane-based polymer represented by chemical formula 1; and a polytetramethylene glycol, the additive is included in an amount of 1-4 parts by weight on the basis of 100 parts by weight of the polyester elastomer, and the polytetramethylene glycol is included in an amount of 3-10 parts by weight on the basis of 100 parts by weight of the polyester elastomer. [Representative drawing] figure 1

Description

Thermoplastic copolymer composition and molded article manufactured therefrom

[Mutual citation with application(s)]

This application claims the interest of priority based on Korean Patent Application No. 10-2019-0099672 filed on August 14, 2019 and Korean Patent Application No. 10-2020-0095350 filed on July 30, 2020, and All contents disclosed in the documents of the Korean patent application are included as part of this specification.

The present invention relates to a thermoplastic copolymer composition, and more particularly, to a thermoplastic copolymer composition that can provide a noise reduction effect used in the production of a molded article such as a constant velocity joint boot.

The constant velocity joint of an automobile is a component installed between the transmission and the tire, and is a device that uniformly transmits power generated from the engine to the tire through the transmission so that both tires rotate at a uniform speed.

Excessive grease is applied to such a constant velocity joint for lubrication, and a rubber boot is wrapped to prevent the lubricating grease from escaping. In other words, the boot used in the constant velocity joint serves to protect the constant velocity joint and grease from external foreign matter. The boot is generally manufactured by extrusion molding a rubber or polyester resin.

On the other hand, when the constant velocity joint transmits power to the tire, it rotates and noise may be generated due to friction between the surface and the surface in the corrugation in the boot. At this time, when there is contamination by foreign matters such as water, salt water, sand, etc. in the lower part of the vehicle, the noise is increased due to friction between the surface and the surface at the wrinkles in the boot, resulting in a loud noise of 90dB or more. In order to improve the noise, various lubricants are added when manufacturing the boot.

As the lubricant, amide, montane, and olefin-based monomeric waxes are used, but these components have poor compatibility with the polyester elastomer, which is the main component of the boot, and thus have the effect of adding a small amount. Insufficient and excessive addition causes surface defects and mechanical properties to decrease due to migration.

Accordingly, there have been attempts to improve noise generation due to friction and contamination by adding organic substances such as polyalkylene glycols, but even in this case, noise improvement was not very effective.

Therefore, there is still a need to develop a material that is more effective in generating noise of a constant velocity joint boot.

〔Prior technical literature〕

[Patent Literature] (Patent Literature 0001) JP 1997-177971 A

The problem to be solved in the present invention is to improve the uniformity of the surface characteristics of the constant velocity joint boot without deteriorating mechanical properties, thereby reducing the noise of the constant velocity joint boot in order to solve the problems mentioned in the technology behind the invention. It is to effectively improve the characteristics and sound insulation characteristics.

That is, the present invention was conceived to solve the problems of the prior art, and it is an object of the present invention to provide a thermoplastic copolymer composition capable of improving low noise characteristics without deterioration of mechanical properties by being used for manufacturing molded articles such as constant velocity joint boot. To do.

According to an embodiment of the present invention for solving the above problems, the present invention is a polyester elastomer; Polytetramethylene glycol; And silica (SiO2) and an additive containing a siloxane-based polymer represented by Formula 1; wherein, the polytetramethylene glycol is included in an amount of 3 to 8 parts by weight based on 100 parts by weight of the polyester elastomer, and the additive is the It provides a thermoplastic copolymer composition comprising 1 to 4 parts by weight based on 100 parts by weight of polyester elastomer:

[Formula 1]

In the above formula, R ₁ to R ₈ are independently an alkyl group having 1 to 10 carbon atoms, and n is an integer of 100 to 10,000.

In addition, the present invention provides a molded article made from the thermoplastic copolymer composition.

As the thermoplastic copolymer composition according to the present invention contains a polyester elastomer and polytetramethylene glycol having good compatibility with the elastomer as a main component, the soft property of the molded article made of the composition according to the present invention is reinforced to prevent mechanical friction. There is an effect of reducing the noise generation. Furthermore, by including an additive including silica (SiO ₂ ) and a siloxane-based polymer that accelerates the elution of the polytetramethylene glycol, it is possible to effectively improve noise generation due to friction or contamination of a molded article such as a constant velocity joint boot. .

Furthermore, when used in the manufacture of a molded article in which hardness and tensile strength are particularly required, such as a constant velocity joint boot, by further including polyalkylene terephthalate in the composition, the effect of improving the mechanical properties of the molded article is achieved.

1 shows the surface conditions of specimens prepared from the thermoplastic copolymer compositions of Examples 1 to 2 and Comparative Examples 2 to 3 of the present invention when left standing for one week.

2 shows a state in which a hollow molded product is mounted at a bending angle of 40° in a noise meter for measuring the number of noise generation cycles of 75 dB or more.

The terms or words used in the description and claims of the present invention should not be construed as limited to their usual or dictionary meanings, and the inventors appropriately explain the concept of terms in order to explain their own invention in the best way. Based on the principle that it can be defined, it should be interpreted as a meaning and concept consistent with the technical idea of the present invention.

Hereinafter, the present invention will be described in more detail to aid understanding of the present invention.

The thermoplastic copolymer composition according to an embodiment of the present invention comprises a polyester elastomer (a); Polytetramethylene glycol (b); And an additive (c) including silica (SiO ₂ ) and a siloxane-based polymer.

In the thermoplastic copolymer composition of the present invention, the polyester elastomer (a) has both the advantages of a thermoplastic resin, which is easy to mold and process, and the advantages of rubber such as flexibility and elasticity, and is used as a material for automobile parts, such as a constant velocity joint boot. It is an ingredient that can be used. In this field, it may be commonly used as a thermoplastic polyester elastomer (TPEE).

Such polyester elastomer can be obtained by a polycondensation reaction of polyester and polyether. The polyester is a unit constituting the hard segment of the elastomer, and may be derived from an aromatic dicarboxylic acid and an aliphatic diol. Examples of the polyester may include polyethylene terephthalate (PET), poly(1,3-propylene terephthalate) (PTT), polybutylene terephthalate (PBT), or a combination thereof or a copolymer thereof. In addition, the polyether is a unit constituting the soft segment of the elastomer, and examples thereof include polyethylene ether glycol (PEG), polypropylene ether glycol (PPG), polytetramethylene glycol (PTMG), and polytetramethylene ether glycol (PTMEG). Or a combination thereof or a copolymer thereof may be included.

The polyester elastomer is a main component of the thermoplastic copolymer composition of the present invention, and 80 to 99% by weight of the total weight of the polyester elastomer (a), polytetramethylene glycol (b) and additive (c), such as 90 to 98% by weight It can occupy %.

The polyester elastomer may preferably be contained in an amount of 80 to 95% by weight, preferably 85 to 95% by weight, more preferably 85 to 90% by weight, based on the total weight of the thermoplastic copolymer composition, and this range It has the advantage of excellent physical property balance and excellent hardness.

Unless otherwise defined herein, the total weight of the thermoplastic copolymer composition means the sum of the weights of all components included in the thermoplastic copolymer composition.

The thermoplastic copolymer composition of the present invention may include polytetramethyleneglycol (PTMG) (b). Polytetramethylene glycol is a component that minimizes noise due to mechanical friction of the molded product by imparting soft properties to a molded product made of a composition containing a polyester elastomer. Specifically, since the polytetramethylene glycol has good compatibility with the polyester elastomer, it can be uniformly dispersed in the polyester elastomer resin, and the polytetramethylene glycol uniformly dispersed in the polyester elastomer resin is molded over time It can slowly elute to the surface of (resin). On the other hand, the constant velocity joint boot is mounted on the drive shaft of the vehicle to protect the constant velocity joint from external environment and internal grease exposure while rotating. The conventional constant velocity joint boot is damaged by continuous surface friction caused by rotational motion and thus the surface is damaged. This was frequent. At this time, the eluted polytetramethylene glycol can reduce the surface friction of the polyester elastomer molded article to prevent damage to the constant velocity joint boot and reduce noise generation.

The polytetramethylene glycol may be included in an amount of 3 to 8 parts by weight, specifically 3 to 5 parts by weight, based on 100 parts by weight of the polyester elastomer. That is, the content of polytetramethylene glycol should be 3 parts by weight or more in order to reduce the surface friction with respect to a molded article made of a thermoplastic copolymer composition and to exhibit noise reduction properties (sound-sounding properties) when the molded article is applied to a constant velocity joint boot. There is a need. On the other hand, the content of the polytetramethylene glycol may be 8 parts by weight or less in order to prevent the decrease in the mechanical properties of the molded article and the product moldability due to excessive elution.

In one embodiment of the present invention, the weight average molecular weight (Mw) of the polytetramethylene glycol may be in the range of 2000 to 5000 g/mol, specifically 2500 to 3500 g/mol, and the weight average molecular weight in this range When it has, it is advantageous in terms of controlling the surface elution rate. Specifically, if the molecular weight is more than 2000 g/mol, mold contamination and work defects can be prevented during product molding due to excessively high dissolution rate.If the molecular weight is less than 5000 g/mol, the dissolution rate of polytetramethylene glycol is It can prevent excessive slowdown. If the elution rate is excessively slow, polytetramethylene glycol cannot be sufficiently eluted onto the surface of the molded article, making it difficult to achieve the purpose of reducing surface friction.

In this description, the weight average molecular weight can be measured using GPC (Gel Permeation Chromatography, waters breeze) unless otherwise defined, and as a specific example, a chloroform:chlorophenol mixed solution (volume ratio 10:1) ) Using GPC (Gel Permeation Chromatography, water breeze) as a relative value to a standard polystyrene (PS) sample.

On the other hand, in the thermoplastic copolymer composition of the present invention, the additive (c) containing the silica (SiO ₂ ) and the siloxane-based polymer accelerates the elution of the polytetramethylene glycol to improve the ductility of the molded article, so that the molded article is For example, it is a component that maximizes the characteristics of noise reduction required when used in a constant velocity joint boot.

More specifically, the siloxane-based polymer may be polydimethylsiloxane (PDMS) having a structure represented by Formula 1 below.

[Formula 1]

In the above formula, R ₁ to R ₈ are independently an alkyl group having 1 to 10 carbon atoms, and n is an integer of 100 to 10,000.

In the above formula, R ₁ to R ₈ are preferably independently an alkyl group having 1 to 5 carbon atoms, more preferably independently an alkyl group having 1 to 3, and in this case, there is an advantage of excellent noise reduction characteristics.

In addition, in the above formula, n is preferably an integer of 500 to 10,000, more preferably an integer of 1,000 to 10,000, even more preferably an integer of 5,000 to 10,000, even more preferably an integer of 5,000 to 7,500, within this range There is an advantage of excellent noise reduction characteristics.

When the siloxane-based polymer is included in the composition containing the polyester elastomer, polytetramethylene glycol can be evenly eluted with respect to the manufactured molded article, and further, the elution rate of polytetramethylene glycol in the molded article is accelerated. That is, in order to accelerate the elution of polytetramethylene glycol, for example, there is a method of lowering the molecular weight of the added polytetramethylene glycol, but in this case, as described above, there is a problem of workability such as mold contamination and poor work during product molding. Not only occurs, it becomes difficult to elute even polytetramethylene glycol in the molded article. By adding the siloxane-based polymer having good compatibility with a polyester elastomer to the composition, it is possible to dissolve polytetramethylene glycol evenly and quickly in the manufactured molded article.

Meanwhile, the additive (c) may further include silica (SiO ₂ ).

The silica may be, for example, fumed silica. Since the siloxane-based polymer contained in the additive (c) is a liquid polymer at room temperature, it is preferable to add the siloxane-based polymer to the composition in the form of pellets with the silica from the viewpoint of storage, transportation, and ease of introduction into the composition. Do. In this case, it is evenly dispersed in the polyester elastomer composition. Further, the fumed silica may include a high molecular weight chain structure, through which entanglement between several polymers in the composition may be induced, thereby improving the mechanical properties of the composition or the molded article manufactured therefrom.

The additive (c) including silica and siloxane polymer capable of the above-described action may be included in an amount of 1 to 4 parts by weight, specifically 1.5 to 3.0 parts by weight, based on 100 parts by weight of the polyester elastomer. In order to exhibit the intended effect of the additive, the content may be 1 part by weight or more, and in particular, it may be 4 parts by weight or less in order to prevent hardness reduction and peeling.

In one embodiment of the present invention, the content of the silica and the siloxane polymer contained in the additive (c) is 1 to 4 parts by weight of the siloxane polymer relative to 1 part by weight of silica, specifically 1.5 to 3.0 parts by weight. I can. When the siloxane-based polymer is used in an amount of 1 part by weight or more relative to 1 part by weight of silica, the purpose of accelerating the elution of polytetramethylene glycol is achieved. Meanwhile, in order to prevent durability degradation due to a decrease in the hardness of the molded product, the siloxane-based polymer is silica 1 It may be used in less than 4 parts by weight compared to parts by weight.

In addition, the thermoplastic copolymer composition of the present invention may further include polyalkylene terephthalate, such as polybutylene terephthalate (PBT), when there is a need to improve mechanical properties such as special hardness reinforcement in the molded article. In the case of a molded article made of a thermoplastic copolymer composition further containing such polyalkylene terephthalate, durability is improved due to prevention of decrease in hardness, and this minimizes mechanical damage to the molded article surface, so that the molded article is indirectly connected to a constant velocity joint boot. When used as such, noise reduction characteristics can be improved.

The content of the polyalkylene terephthalate may be 3 to 8 parts by weight, specifically 3 to 5 parts by weight, based on 100 parts by weight of the polyester elastomer.

When the polyalkylene terephthalate is used in an amount of less than 3 parts by weight based on 100 parts by weight of the polyester elastomer, the effect of reinforcing hardness may be insignificant, and when it is used in an amount exceeding 8 parts by weight, the hardness is excessively high and the elasticity of the molded article And may have an adverse effect on the noise reduction characteristics (sound-freezing characteristics).

In addition, the thermoplastic copolymer composition of the present invention may further include various other additives such as a compatibilizer, an ionomer, a heat stabilizer, a light stabilizer, a lubricant, and a carbon black pigment, if necessary.

The compatibilizer is a chain extender and functions to control the viscosity of the polymer composition. The compatibilizer may include, for example, a glycidyl group-modified ethylene-octene-based copolymer (EOR-GMA), and the glycidyl group-modified ethylene-octene-based copolymer is grafted with glycidyl methacrylate. It may be a modified ethylene-octene-based copolymer (graft content of glycidyl methacrylate is 8 to 20% by weight).

On the other hand, the ionomer performs functions such as increasing the melt tension (reinforcing the moldability of the product), increasing chemical resistance, and reinforcing abrasion resistance, and a sodium-based ionomer, such as Surlyn 8920 manufactured by Dupont, may be used.

The heat stabilizer serves to inhibit or block thermal decomposition of the composition when the thermoplastic copolymer composition is mixed or molded at high temperature. The heat stabilizer is not particularly limited, and for example, an amine type, a phenol type, or a phosphite type may be used.

As the light stabilizer, an ultraviolet absorber or a Hindered Amine Light Stabilizer (HALS) that protects against decomposition by exposure to ultraviolet light may be used. As the ultraviolet absorber, hydroxy benzophenone or benzotriazoles may be used, but is not limited thereto. In addition, the amine light stabilizer is bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidyl Mixtures of sebacates may be used, but are not limited thereto.

As the lubricant, amide, montan, or olefin-based monomeric wax may be used.

Each of the various other additives may be used in an amount that does not impair the intrinsic properties of the thermoplastic copolymer composition of the present invention, for example, in an amount of 0.1 to 5% by weight, or 0.1 to 3% by weight based on the total amount of the composition. Can be used.

The thermoplastic copolymer composition of the present invention may be prepared by heating and melting mixing the above-described components into pellets, and the melt mixing temperature may be appropriately selected in consideration of the melting point of the polyester elastomer. For example, melt mixing may be performed at 200°C to 300°C, specifically 200°C to 270°C.

The thermoplastic copolymer has a flow index (Melt Index, g/10 min) measured according to ISO1133 (230° C., 10 kg condition), preferably 18 g/10 min or less, more preferably 17 g/10 min or less, further It is preferably 16 g/10min or less, and a specific example is 5 to 18 g/10min, a preferred example is 10 to 18 g/10min, a more preferred example is 12 to 18 g/10min, and a more preferred example is 14 to 17 g/ 10 min, a more preferable example is 15 to 16 g/10 min, and there is an advantage of excellent injection molding within this range.

The thermoplastic copolymer has a hardness (Shore D) measured according to ISO868 preferably 33 or more, specific examples 33 to 40, preferred examples 33 to 38, more preferred examples 33 to 37, and within this range In addition, there is an advantage of excellent hardness properties and excellent balance of properties.

The thermoplastic copolymer has a tensile strength (MPa) measured according to ISO527, preferably 15 MPa or more, a specific example is 15 to 25 MPa, a preferred example is 15 to 20 MPa, and a more preferred example is 15 to 16 MPa. , In this range, there is an advantage of excellent strength and excellent balance of properties.

The thermoplastic copolymer has a tensile elongation (%) measured according to ISO527 is preferably 260% or more, more preferably 270% or more, even more preferably 277% or more, and a specific example is 260 to 290%, preferably An example is 270 to 290%, a more preferable example is 275 to 285%, a more preferable example is 275 to 280%, and there is an advantage of excellent mechanical properties and excellent balance of properties within this range.

The thermoplastic copolymer has a number of noise generation cycles of 75dB or more measured under the condition of a bending angle of 40° of the sample by a sound level meter, preferably 34 or more, more preferably 38 or more, more preferably 41 or more, most preferably 42 or more. And, a specific example is 34 to 45, and within this range, there is an advantage of excellent noise reduction effect and excellent physical property balance.

The thermoplastic copolymer preferably has a friction coefficient of 0.05 or less, more preferably 0.045 or less, and even more preferably 0.042 while moving a ball tip with a weight of 10 kg on a square specimen of 100 x 100 x 2 (mm) by 30 mm. Hereinafter, it is even more preferably 0.040 or less, and there is an advantage that the noise reduction effect is excellent within this range.

The thermoplastic copolymer preferably has a glossiness of 5 or less, more preferably 3 or less, more preferably 1 or less, and noise reduction properties within this range, as measured under the condition of a reflection angle of 60° after being left for a week at room temperature after injection. There is this outstanding advantage.

The thermoplastic copolymer preferably has a reduction rate of glossiness measured after injection at a gloss immediately after injection measured under a reflection angle of 60° and left at room temperature for a week after injection at least 70%, more preferably at least 80%, and more preferably Is more than 90%, and there is an advantage of excellent noise reduction characteristics within this range.

The thermoplastic copolymer composition of the present invention as described above can be used to manufacture a molded article such as a constant velocity joint boot by extrusion molding, and the molded article maintains mechanical properties and improves soft properties, thereby reducing friction and contamination during rotation. Noise generation can be improved.

Accordingly, the present invention further provides a molded article prepared from the thermoplastic copolymer composition.

On the other hand, the number of cycles for generating noise of 75dB or more for the molded article was measured by the following method.

(1) After installing the noise meter at a bending angle of 40°, it was rotated at 150 rpm. The mounting state is shown in FIG. 2. The surrounding environment in which the measurement was made was kept at room temperature and noise generation conditions of 75dB or less.

(2) Calcium chloride (CaCl ₂ ) 15% by weight + calcium hydroxide (Ca(OH) ₂ ) 15% by weight of a mixed aqueous solution was sprayed 25g for 30 seconds.

(3) 10 g of sand with a particle size of 0.8 to 1.2 mm was sprinkled over 10 seconds.

(4) It was idle for 60 seconds.

(5) The processes (2) to (4) were repeated.

(6) One repetition of the above process is one cycle, and one cycle is a total of 100 seconds.

If a noise of 75dB or more occurs during a cycle, the rotation is maintained, but if the noise lasts for more than 3 minutes, the cumulative number of cycles of the cycle is regarded as the number of noise generation cycles of 75dB or more and recorded.

It may include a constant velocity joint boot for a vehicle having preferably 40 to 80 noise generation cycles measured by the above method.

Hereinafter, the present invention will be described in more detail by examples. However, the following examples are intended to illustrate the present invention, and that various changes and modifications are possible within the scope of the present invention and the scope of the technical idea is obvious to those skilled in the art, and the scope of the present invention is not limited thereto.

Examples 1 to 4 and Comparative Examples 1 to 7

The components of the composition shown in Table 1 below were melted and mixed at 230° C. using a twin-screw extrude to pelletize to prepare a thermoplastic copolymer resin composition. Here, the composition components used in each Example and Comparative Example are as follows.

First, the polyester elastomer was prepared by a polycondensation reaction of polybutylene terephthalate and polytetramethylene glycol, and a flow index of 20 g/10min (230°C, 2.13kg) was used. Polytetramethylene glycol (PTMG) was manufactured by BASF (K-PTG) and had a weight average molecular weight of 3,000 g/mol.

On the other hand, additive (c) is a polydimethylsiloxane (PDMS) having a structure of Formula 1, a siloxane-based polymer having an n of 6000, and a fumed silica manufactured by Wacker (Genioplast PelletS), compared to 1 part by weight of the fumed silica. The acid-based polymer was mixed in a pellet form in an amount of 2.34 parts by weight and compounded.

Shenyang Ketong Plastic's KT-20 was used as a compatibilizer, and DuPont's brand name Surlyn 8920 was used as an ionomer. Meanwhile, a mixture of 0.5% by weight of the brand name Naugard445 and 0.5% by weight of the brand name Songnox1010 was used as a heat stabilizer, 0.2% by weight of the brand name Chimassorb 944 was used as a light stabilizer, and a mixture of 0.3% by weight of the brand name OP WAX and 0.3% by weight of the brand name LC104N was used as a lubricant. Used. Carbon black EC300J was used as a carbon black pigment.

The prepared composition was vacuum-dried at 85° C. for 4.5 hours, and then injection-molded at a temperature of 230° C. to prepare a 100 mm×100 mm×2T square disk specimen for measuring tensile strength, tensile elongation, and hardness. A hollow molded product was manufactured to measure the number of cycles of noise generation over 75dB.

Experimental Example 1

The physical properties of the specimens of the thermoplastic copolymer compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 7 were measured by the following method. The results are shown in Tables 1 and 2 below.

1) Flow index (Melt Index, g/10 min): The flow index of the specimen was measured according to standard measurement ISO1133 (230°C, 10kg condition).

2) Hardness (Shore D): The hardness of the specimen was measured in Shore D type according to standard measurement ISO868.

3) Tensile strength and tensile elongation (MPa and %): The tensile strength (MPa) and tensile elongation (%) of the specimen were measured according to standard measurement ISO527-2-5A, respectively.

4) Number of noise generation cycles: The number of noise generation cycles of 75dB or more for the molded product was measured.

division		Example
		One	2	3	4
Composition (unit: parts by weight)	Thermoplastic polyester elastomer (TPEE)	100	100	100	100
	Polytetramethylene glycol (PTMG)	5	5	5	4
	Additive (c)	2	2	3	2
	Polybutylene terephthalate (PBT)	-	5	5	5
	Compatibilizer	One	One	One	One
	Ionomer	2	2	2	2
	Heat stabilizer	One	One	One	One
	Light stabilizer	0.2	0.2	0.2	0.2
	Lubricant	0.6	0.6	0.6	0.6
	Carbon black pigment)	0.5	0.5	0.5	0.5
Properties	Flow index (g/10 min)	15	16	18	18
	Hardness(Hs)	33	37	34	38
	Tensile strength (MPa)	21	20	19	20
	Tensile elongation (%)	277	280	270	280
	Number of noise generation cycles	38	42	40	35

division		Comparative example
		One	2	3	4	5	6	7
Composition (unit: parts by weight)	Thermoplastic polyester elastomer (TPEE)	100	100	100	100	100	100	100
	Polytetramethylene glycol (PTMG)	-	5	5	5	5	5	5
	Additive (c)	-	-	-	-	-	0.5	5
	Polybutylene terephthalate (PBT)	-	-	5	One	10	5	5
	Compatibilizer	One	One	One	One	One	One	One
	Ionomer	2	2	2	2	2	2	2
	Heat stabilizer	One	One	One	One	One	One	One
	Light stabilizer	0.2	0.2	0.2	0.2	0.2	0.2	0.2
	Lubricant	0.6	0.6	0.6	0.6	0.6	0.6	0.6
	Carbon black pigment)	0.5	0.5	0.5	0.5	0.5	0.5	0.5
Properties	Flow index (g/10 min)	9	19	19	17	15	16	20
	Hardness(Hs)	37	34	40	33.5	38	37	32
	Tensile strength (MPa)	20	20	20	21	22	20	19
	Tensile elongation (%)	280	280	285	265	261	275	270
	Number of noise generation cycles	2	17	25	18	26	30	40

Referring to Tables 1 and 2, in the case of Examples 1 to 4 of the present invention for a molded article made of a thermoplastic copolymer composition comprising an additive including a siloxane-based polymer and silica at the same time as polytetramethylene glycol, the noise generation cycle It was confirmed that the number (the number of cycles in which the noise lasted for 3 minutes or more) was 35 to 42, which was excellent. In other words, the elution of polytetramethylene glycol is accelerated by an additive containing a siloxane-based polymer and silica, thereby imparting ductility (slip) to the surface of the molded article, thereby improving the noise reduction characteristics of the molded article. In the case of a molded article made of the non-added composition (Comparative Example 1), the noise lasted for more than 3 minutes in the second cycle, so there was little noise reduction effect, and even if polytetramethylene glycol was added, an additive containing a siloxane-based polymer and silica Even in the case of a molded article (Comparative Example 2) made of a composition to which no is added, the number of noise generation cycles is 17, indicating that the noise reduction effect is still inferior compared to the Example. This is believed to be due to the fact that the elution rate of polytetramethylene glycol was further increased by the additive containing the siloxane polymer and silica, thereby effectively reducing the surface friction of the molded article.

On the other hand, looking at Examples 1 and 2 and Comparative Examples 3 to 5, when a certain amount of polybutylene terephthalate (PBT) is added, it can be confirmed that the number of noise generation cycles of the molded article is partially delayed, and at the same time, the hardness characteristics of the molded article It was confirmed that this was improved at the same time. However, it can be seen that the effect of improving the hardness and flow index decreases when the amount of PBT added is too large.

In Comparative Example 6, when a small amount of an additive including a siloxane-based polymer and silica is added in a small amount of 0.5 parts by weight, it can be seen that the noise reduction effect of the molded article is not properly exhibited compared to Example 2, and as in Comparative Example 7 When an additive containing a polymer and silica is added in an excessive amount, the noise reduction characteristics of the molded article are exhibited, but the hardness characteristics are deteriorated. In particular, the flow index was found to flow down during molding because the flow index was too high.

Experimental Example 2

FIG. 1 shows the surface conditions of the specimens prepared from Examples 1 to 2 and Comparative Examples 2 to 3 in which PTMG was used in the same amount in the thermoplastic copolymer composition and left for one week.

As can be seen in Figure 1, under the condition that PTMG was used in the same amount, Example 1 in which an additive including silica and a siloxane-based polymer was added, and Example 2 in which PBT was additionally reinforced, had no gloss on the surface of the specimen. On the other hand, the specimens of Comparative Examples 2 and 3 to which silica and siloxane-based polymers were not added had gloss. This accelerates the elution of PTMG to the extent that the silica and siloxane-based polymers used in Examples 1 to 2 lose the surface gloss of the specimen, and when this phenomenon is applied to a molded article such as a constant velocity joint boot, the effect of noise reduction in the noise test is achieved. It is believed to have been achieved.

Experimental Example 3

The coefficient of friction and gloss of the specimens of the thermoplastic copolymer composition prepared in Example 2 and Comparative Example 3 were measured by the following method, and the results are shown in Table 3 below.

5) Friction coefficient: 100 x 100 x 2 (mm) A ball tip with a weight of 10 kg on a square specimen was measured while moving 30 mm.

6) Glossiness: Glossmeter TC-108DPA of Tokyo Denshoku Co., Ltd was measured under the condition of a reflection angle of 60°.

division		Example 2	Comparative Example 3
Coefficient of friction		0.035	0.064
Gloss	Immediately after injection	25	24.2
	After leaving at room temperature for 1 week	0.8	15
	Reduction rate (%)	96.8	38

Referring to Table 3, it can be seen that the thermoplastic copolymer composition containing the additive according to the present invention (Example 2) has a significantly lower coefficient of friction compared to Comparative Example 3 that does not contain the additive, and has excellent frictional noise resistance. In addition, the thermoplastic copolymer composition containing the additive according to the present invention (Example 2) did not have a significant difference in gloss immediately after injection compared to Comparative Example 3 without the additive, but at room temperature for a week after injection. The glossiness of Example 2 was significantly lowered after being left to stand, whereas the glossiness of Comparative Example 3 was not significantly lowered. This is because the additive (c) used in Example 2 lost the surface gloss of PTMG. It can be seen that this is the result of accelerating the dissolution, and it can be seen that the dissolution of the PTMG from the constant velocity joint boot to the surface leads to noise reduction.

Claims (16)

1. Polyester elastomer;

   Polytetramethylene glycol; And

   Including; silica and an additive containing a siloxane-based polymer represented by Chemical Formula 1,

   The additive is a thermoplastic copolymer composition containing 1 to 4 parts by weight based on 100 parts by weight of the polyester elastomer:

   [Formula 1]

   

   In the above formula, R ₁ to R ₈ are independently an alkyl group having 1 to 10 carbon atoms, and n is an integer of 100 to 10,000.
2. The method of claim 1,

   The polyester elastomer is a thermoplastic copolymer composition containing 80 to 95% by weight based on the total weight of the thermoplastic copolymer composition.
3. The method of claim 1,

   The polytetramethylene glycol is a thermoplastic copolymer composition containing 3 to 8 parts by weight based on 100 parts by weight of the polyester elastomer.
4. The method of claim 1,

   The content of silica and the siloxane-based polymer represented by Formula 1 among the additives is 1 to 4 parts by weight of the siloxane-based polymer represented by Formula 1 relative to 1 part by weight of the silica.
5. The method of claim 1,

   A thermoplastic copolymer composition having a weight average molecular weight of 2000 g/mol to 5000 g/mol of the polytetramethylene glycol.
6. The method of claim 1,

   The silica is a thermoplastic copolymer composition of fumed silica.
7. The method of claim 1,

   The composition is a thermoplastic copolymer composition further comprising a polyalkylene terephthalate.
8. The method of claim 7,

   The polyalkylene terephthalate is a thermoplastic copolymer composition of polybutylene terephthalate.
9. The method of claim 7,

   The polyalkyl terephthalate is a thermoplastic copolymer composition containing 3 to 8 parts by weight based on 100 parts by weight of the polyester elastomer.
10. The method of claim 1,

    The polyester elastomer is a thermoplastic copolymer composition obtained by a polycondensation reaction of polyester and polyether.
11. The method of claim 10,

    The polyester is polyethylene terephthalate (PET), poly(1,3-propylene terephthalate) (PTT), polybutylene terephthalate (PBT), or a combination thereof or a copolymer thereof.
12. The method of claim 10,

    The polyether is polyethylene ether glycol (PEG), polypropylene ether glycol (PPG), polytetramethylene glycol (PTMG), polytetramethylene ether glycol (PTMEG), or a combination thereof or a copolymer thereof.
13. The method of claim 1,

    The thermoplastic copolymer composition has a flow index of 18 g/10min or less measured under conditions of 230° C. and 10 kg according to ISO1133, and the number of noise generation cycles of 75 dB or more measured under the condition of 40° bending angle of the sample by a sound level meter is 34 or more. Coalescence composition.
14. The method of claim 1,

    The thermoplastic copolymer composition is a thermoplastic copolymer composition, characterized in that the reduction rate of the glossiness measured after the glossiness immediately after injection measured under the condition of the reflection angle of 60° and left at room temperature for a week after injection is 70% or more.
15. A molded article comprising the thermoplastic copolymer composition of any one of claims 1 to 14.
16. The method of claim 15,

    The molded article is a molded article that is a constant velocity joint boot.

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