KR102431823B1 - Thermoplastic polyester elastomer resin composition having good anti-squeak noise property and molded article comprising the same - Google Patents

Abstract

The present invention relates to a thermoplastic polyester-based elastomer resin composition and a molded article comprising the same, and more particularly, by including specific additives in a specific content range together with the thermoplastic polyester-based elastomer resin, tensile strength, elongation, fluidity and extrusion A thermoplastic polyester-based elastomer resin composition and a molded article comprising the same, particularly, for example, a constant velocity joint boot, exhibiting an excellent balance of mechanical properties for blow molding, such as properties, and a low friction coefficient and excellent anti-squeak noise characteristics It is manufactured by blow molding, such as, and relates to a molded article for automotive parts that requires a low coefficient of friction and low noise.

Description

Thermoplastic polyester elastomer resin composition having good anti-squeak noise property and molded article comprising the same

The present invention relates to a thermoplastic polyester-based elastomer resin composition and a molded article comprising the same, and more particularly, by including specific additives in a specific content range together with the thermoplastic polyester-based elastomer resin, tensile strength, elongation, fluidity and extrusion A thermoplastic polyester-based elastomer resin composition and a molded article comprising the same, particularly, for example, a constant velocity joint boot, exhibiting an excellent balance of mechanical properties for blow molding, such as properties, and a low friction coefficient and excellent anti-squeak noise characteristics It is manufactured by blow molding, such as, and relates to a molded article for automotive parts that requires a low coefficient of friction and low noise.

Thermoplastic polyester-based elastomer resins are being actively developed for use in automobile parts based on excellent heat resistance, chemical resistance, and cold resistance. In particular, constant velocity joint boots belonging to the suspension system, gearbox bellows belonging to the steering system, air ducts and intercooler pipes around the engine, and interior materials are largely used for dashboard skins or buttons. Since these blow molded products are produced through a blow process in a molten state, the resin in the molten state must have excellent melt viscosity and melt tension, and the parison shape must be maintained during extrusion blow. In order to realize the properties of the material for blow molding, there is a method of using a reactive additive. When a reactive additive is used, it is possible to provide not only physical properties for blow molding, but also excellent heat resistance to molded products.

Recently, with the low noise of automobile engines and the release of hybrid vehicles, consumers have begun to recognize the squeak (squeak noise) of the constant velocity joint boot that occurs when operating the vehicle as noise, and as a result, consumer complaints gradually increase. is a trend to In addition, due to the nature of the constant velocity joint boots, they are constantly exposed to rainwater, etc., so the creak sound is heard louder due to rainwater.

In Korean Patent Laid-Open No. 10-2008-0061628, an attempt was made to reduce the coefficient of friction by adding an amide-based lubricant to the thermoplastic elastomer resin. However, the resin produced in this way does not solve the squeaking sound that occurs when exposed to moisture such as rainwater, and the surface film formed by the amide-based lubricant does not withstand friction for a long time, so it has a disadvantage that it cannot maintain low-joint characteristics. . In addition, there is a method of reducing the friction coefficient by increasing the surface roughness to reduce the friction area, but there is a problem in that the nano-sized structure exposed on the surface collapses.

An object of the present invention is to exhibit a low friction coefficient and anti-squeak noise characteristics while having mechanical properties suitable for blow molding, and, in particular, to maintain a low friction coefficient even in a wet environment such as rain to exhibit low noise characteristics. To provide a thermoplastic polyester-based elastomer resin composition and a molded article comprising the same.

The present invention to solve the above problems, (1) a thermoplastic polyester-based elastomer resin; (2) fluorinated hydrocarbon additives; and (3) a reactive additive; based on 100 wt% of the total composition, 0.4 to 4.9 wt% of the fluorinated hydrocarbon additive, and 0.4 to 2.9 wt% of the reactive additive, a thermoplastic polyester-based elastomer resin A composition is provided.

According to another aspect of the present invention, there is provided a molded article comprising the thermoplastic polyester-based elastomer resin composition of the present invention.

In one embodiment, the molded article is manufactured by blow molding.

More specifically, the molded article is an automobile part.

The thermoplastic polyester-based elastomer resin composition of the present invention has an excellent balance of mechanical properties for blow molding such as tensile strength, elongation, fluidity and extrudability, and at the same time has a low coefficient of friction and excellent anti- Since it exhibits squeak noise) characteristics, it can be particularly suitably used for manufacturing blow-molded products for automobiles (eg, constant velocity joint boots, etc.) that require low friction coefficient and low noise even in environments such as rain.

Hereinafter, the present invention will be described in more detail.

The resin composition of the present invention includes a thermoplastic polyester-based elastomer (TPEE) resin.

The thermoplastic polyester-based elastomer resin usable in the present invention is a thermoplastic block copolymer having a hard hard segment and a soft soft segment.

The hard segment may be prepared by polymerizing an aromatic dicarboxyl compound and a diol compound.

Examples of the aromatic dicarboxyl compound include terephthalic acid (TPA), isophthalic acid (IPA), 1,5-dinaphthalenedicarboxylic acid (1,5-NDCA), 2,6-dinaphthalenedicarboxylic acid (2,6-NDCA), dimethyl terephthalate (DMT), dimethyl isophthalate, or a combination thereof may be used. , preferably DMT.

As the diol compound, a linear or cyclic aliphatic diol having 2 to 8 carbon atoms is used. As the aliphatic diol, ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, or a combination thereof may be used, preferably Preferably, 1,4-butanediol is used.

As the soft segment, a polyalkylene oxide polymerization unit may be used.

As the polyalkylene oxide, polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol (hereinafter referred to as PTMEG), or a combination thereof may be used. and PTMEG is preferably used.

In addition, in order to increase the melt strength of the thermoplastic polyester-based elastomer resin to improve the stability of the TPEE strand during TPEE production, thereby increasing productivity, a branching agent may be additionally used in the production of TPEE. . As the branching agent, glycerol, pentaerythritol, neopentylglycol, or a combination thereof may be used, and glycerol is preferably used. In addition, the preparation of TPEE can be carried out in the presence of a suitable catalyst (eg, tetra-n-butoxy titanium (TBT)).

In general, the thermoplastic polyester-based elastomer resin that can be used in the present invention can be prepared through melt polymerization consisting of two steps of an oligomerization reaction and a polycondensation reaction after the above-mentioned components are added to a reactor. The oligomerization reaction is carried out at 140 to 215° C. for 3 to 4 hours, and the polycondensation reaction is performed at 210 to 250° C. for 4 to 5 hours, and the pressure is gradually reduced from 760 to 0.3 torr to produce a branched elastomer. do.

The soft segment content in 100% by weight of the thermoplastic polyester-based elastomer resin that can be used in the present invention may vary, for example, may be in the range of 5 to 75% by weight, in particular, considering blow molding processability, mechanical strength, flexibility, etc. If so, it is preferably 30 to 70% by weight. If the content of the soft segment in the thermoplastic polyester-based elastomer resin is too small, the hardness increases and flexibility is difficult to expect.

The thermoplastic polyester-based elastomer resin that can be used in the present invention preferably has an intrinsic viscosity of 1.3 to 2.0 dl/g, and more preferably, may have an intrinsic viscosity of 1.3 to 1.8 dl/g. In addition, the thermoplastic polyester-based elastomer that can be used for reaction extrusion preferably has a shore hardness of D-30 to D-60, and more preferably a shore hardness of D-40 to D-55.

In one embodiment, the resin composition of the present invention may include 92.2 to 99.2% by weight of the thermoplastic polyester-based elastomer resin, based on 100% by weight of the total composition. If the content of the thermoplastic polyester-based elastomer resin in the resin composition of the present invention is less than the above level, the original mechanical properties of the resin may not appear properly. As a result, the low noise (anti-squeak noise) may be deteriorated, or the content of the reactive additive may be relatively reduced to deteriorate mechanical properties and moldability.

More specifically, the content of the thermoplastic polyester-based elastomer resin in 100% by weight of the resin composition of the present invention is 92.5% by weight or more, 93% by weight or more, 93.5% by weight or more, 94% by weight or more, 94.5% by weight or more, or 95 It may be greater than or equal to 99% by weight, and may be less than or equal to 99% by weight, less than or equal to 98.5% by weight, less than or equal to 98% by weight, less than or equal to 97.5% by weight, less than or equal to 97% by weight, or less than or equal to 96.5% by weight, but is not limited thereto.

The resin composition of the present invention also contains a fluorinated hydrocarbon additive.

The fluorinated hydrocarbon additive is a hydrocarbon compound having one or more fluorine functional groups, and is used to impart low-joint properties to the composition of the present invention. As it has hydrophobicity, it repels water even if it gets wet on the surface, so that it can maintain low noise characteristics even in environments such as rain.

In one embodiment, the fluorinated hydrocarbon additive may be a fluorinated polyolefin, more specifically, a fluorinated polyethylene, and more specifically, polytetrafluoroethylene (PTFE) (trade name: Teflon) ), but is not limited thereto.

The resin composition of the present invention includes 0.4 to 4.9% by weight of the fluorinated hydrocarbon additive based on 100% by weight of the total composition. If the content of the fluorinated hydrocarbon additive in 100% by weight of the resin composition of the present invention is less than 0.4% by weight, the anti-squeak noise characteristic does not appear properly. -swelling) makes extrusion difficult, and may even make extrusion impossible.

More specifically, the content of the fluorinated hydrocarbon additive in 100 wt% of the resin composition of the present invention may be 0.5 wt% or more, 1 wt% or more, 1.5 wt% or more, or 2 wt% or more, and also 4.5 wt% or less, 4 Weight % or less, 3.5 wt% or less, or 3 wt% or less may be, but is not limited thereto.

The resin composition of the present invention also contains a reactive additive.

The reactive additive is a compound having one or more reactive groups, and serves to extend the chain by reacting with the thermoplastic polyester-based elastomer resin during extrusion of the composition, and to increase the melt strength of the composition to enable blow molding. used

In one embodiment, the reactive additive may be at least one selected from the group consisting of compounds having an isocyanurate group, an isocyanate group, a carbodiimide group, or an epoxy group, and more specifically, a compound having an isocyanate group. , More specifically, it may be a cyclic compound including an isocyanate group at the terminal, but is not limited thereto. The reactive group included in the reactive additive may be one or more, more specifically, two or more or three or more per molecule, but is not limited thereto. Also preferably, the reactive additive compound has the reactive group at its terminus.

In one embodiment, the reactive additive includes a compound containing two or more isocyanate groups, such as naphthalene diisocyanate, hexamethylene diisocyanate, isoprone diisocyanate, toluene diisocyanate, 4,4-cyclohexanebismethyl isocyanate, 4,4'-dicyclohexylmethane diisocyanate, methylene diphenyl diisocyanate, or a mixture of two or more thereof may be used, but is not limited thereto.

In another embodiment, as the reactive additive, a compound having an isocyanurate group and an isocyanate group together, such as naphthalene diisocyanate-isocyanurate, hexamethylene diisocyanate-isocyanurate, isoprondiisocyanate-isocy Anurate, toluene diisocyanate - isocyanurate, 4,4-cyclohexanebismethyl isocyanate - isocyanurate, 4,4'-dicyclohexylmethane diisocyanate - isocyanurate, methylene diphenyl diisocyanate - Isocyanurate or a mixture of two or more thereof may be used, but is not limited thereto.

In a preferred embodiment, the reactive additive is an isocyanurate compound formed by bonding three molecules of aliphatic diisocyanate, for example, (2,4,6-trioxotriazine) which is a hexamethylene diisocyanate trimer (HDI trimer) having the following structure: -1,3,5(2H,4H,6H)-triyl)tris(hexamethylene) isocyanate, or an isocyanate compound formed by combining two molecules of aromatic diisocyanate, for example, a methylenediphenyl diisocyanate dimer having the following structure ), but is not limited thereto.

[Hexamethylene diisocyanate trimer]

[Methylenediphenyl diisocyanate dimer]

The resin composition of the present invention includes 0.4 to 2.9% by weight of the reactive additive based on 100% by weight of the total composition. If the reactive additive content in 100% by weight of the resin composition of the present invention is less than 0.4% by weight, the melt index of the composition becomes too high, and parison sagging occurs during blow molding. castle goes down

More specifically, the content of the reactive additive in 100 wt% of the resin composition of the present invention may be 0.5 wt% or more, 0.6 wt% or more, or 0.7 wt% or more, and also 2.5 wt% or less, 2 wt% or less, 1.5 wt% or less % or less or 1 wt% or less, but is not limited thereto.

In one embodiment, the resin composition of the present invention may further include a catalyst to promote the reaction of the reactive additive. As such a catalyst, a metal-based, organometallic, or organic-based catalyst may be used, and the amount used may be, for example, 0.003 to 0.03% by weight based on 100% by weight of the total composition, but is not limited thereto.

In one embodiment, the resin composition of the present invention may further include an antioxidant. Antioxidants that can be additionally used in the present invention include hindered amine, hindered phenol, phosphite, amide or thioester antioxidants, or a combination thereof, more specifically 4,4'-bis(α,α-diphenylbenzyl)diphenyl amine (eg, Naugard 445, Chemtura), octadecyl-3-(3,5-di -tert-butyl-4-hydroxyphenyl)-propionate (Irganox 1076, Ciba) and the like may be mentioned, but are not limited thereto. These antioxidants may be included in an amount of, for example, 0.05 to 1.0% by weight, or 0.1 to 0.5% by weight, based on 100% by weight of the resin composition of the present invention.

The resin composition of the present invention may exhibit a low coefficient of friction and excellent anti-squeak noise characteristics in a wet environment as well as in a dry environment.

In one embodiment, the friction noise of the resin composition of the present invention may be 45 to 56 dB in a dry state, and 47 to 58 dB in a wet state. The friction noise in the dry state can be measured, for example, using a noise meter while rubbing two disc-shaped injection specimens of the composition at a rotation speed of 100 rpm, and the friction noise in the wet state is an injection specimen completely wet with water. For both, it can be measured in the same way as the friction noise in the dry state.

In one embodiment, the static friction coefficient of the resin composition of the present invention may be 0.1555 to 0.1855, more specifically 0.16 to 0.18, even more specifically 0.1633 to 0.1846, the dynamic coefficient of friction is 0.03 to 0.1 days may be, more specifically 0.035 to 0.05, and more specifically 0.0367 to 0.0857. The friction coefficient may be measured according to ASTM D1894.

In one embodiment, the surface contact angle of the resin composition of the present invention may be 97 to 105 °, more specifically, 97.5 to 101.5 °. The surface contact angle may be a static contact angle measured after dropping 13 μL of water droplets on a disk-shaped injection specimen of the composition.

The thermoplastic polyester-based elastomer resin composition of the present invention exhibits mechanical properties suitable for blow molding, and at the same time exhibits a low coefficient of friction and excellent anti-squeak noise characteristics in a wet environment as well as in a dry environment. It can be particularly suitably used for manufacturing blow-molded products for automobiles (eg, constant velocity joint boots, etc.) that require low friction coefficient and low noise even in the environment of For example, the constant velocity joint boot of a vehicle manufactured with the resin composition of the present invention can maintain low friction noise in both a dry environment and a wet environment, and thus has lower noise (ie, low noise) characteristics than conventional constant velocity joint boots.

Therefore, according to another aspect of the present invention, there is provided a molded article comprising the thermoplastic polyester-based elastomer resin composition of the present invention.

In one embodiment, the molded article is manufactured by blow molding, and in this case, a conventional blow molding method and apparatus may be used without particular limitation.

More specifically, the molded article may be an automobile part, and more specifically, may be a constant velocity joint boot.

Hereinafter, the present invention will be described in more detail through Examples and Comparative Examples. However, the scope of the present invention is not limited to these examples.

[Example]

Preparation Example 1: Preparation of a thermoplastic polyester-based elastomer (TPEE) having a shore hardness of D-40

34.6% by weight of dimethyl terephthalate (DMT), 25% by weight of 1,4-butanediol, 40.2% by weight of polyoxytetramethylene glycol (PTMEG) having a molecular weight of 2,000, and 0.065% by weight of glycerol were placed in an oligomerization reactor, and tetra-n- as a catalyst Butoxy titanium (TBT) 0.025% by weight was added. The reactor temperature was raised from 140°C to 215°C for 120 minutes, and reacted for an additional 120 minutes while maintaining 215°C. The reaction was terminated when the reaction rate converted using the amount of methanol as the reaction effluent reached 99% or more. Thereafter, 0.04 wt% of TBT as a catalyst and 0.07 wt% of a thermal stabilizer (Irganox 1010) were added, and a polycondensation reaction was performed. The polycondensation reaction was carried out by raising the reactor temperature from 215°C to 250°C for 120 minutes and reacting for an additional 120 minutes while maintaining 250°C, wherein the reactor pressure was reduced from 760 to 0.3 torr for 1 hour, and the remaining 3 The time was set to a vacuum condition of 0.3 torr or less, and the final pressure was adjusted to 0.3 torr or less to prepare a thermoplastic polyester elastomer (TPEE) having a shore hardness of D-40. The intrinsic viscosity of the thus-prepared TPEE was 1.7 dl/g (measured in a solvent of phenol/tetrachloroethane (TCE) = 50/50).

Examples 1 to 3 and Comparative Examples 1 to 9

The components shown in Table 1 below were mixed according to their respective contents, and then melt-kneaded and extruded using a twin-screw extruder, cooled in a cooling bath, and then pelletized to prepare pellets. Specifically, the raw materials were mixed and put into the hopper of the extruder, and the extruder was extruded in a state in which the temperature of the extruder was set to 150° C. in the hopper portion and 190 to 230° C. in the remaining portion. A twin screw (L/D=40) was used, and the extrusion conditions were: a die diameter of 26 phi, two kneading blocks, a feed rate of 10 to 12 kg/hr, and an extruder screw rotation speed of 150 to 200 rpm.

[Table 1]

[Raw Ingredients Used]

TPEE: Thermoplastic polyester-based elastomer resin prepared in Preparation Example 1

Reactive additive 1: Carbodiimide compound having an isocyanate group of the following structure (Carbodiimide, Diphenylmethane-4,4'-diisocyanate (MDI)) (MM103C, LUPRANATE)

Reactive additive 2: an isocyanurate compound having an isocyanate group of the following structure ((2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl)tris(hexamethylene) isocyanate)(TLA-100) , Duranate)

Silicone Resin: Silicone Masterbatch

Fluorinated hydrocarbon additive: polytetrafluoroethylene (PTFE)

Graphite: KS44

Silicone-based additive: silicone gum

Antioxidant: SONG1076

Heat-resistant stabilizer: KY405

The following physical properties were measured for the prepared thermoplastic polyester-based elastomer resin composition, and the results are summarized in Table 2 below.

[Physical properties and measurement method]

Tensile strength [Kgf/cm ² ]: It was evaluated according to ASTM D638.

Tensile elongation [%]: It was evaluated according to ASTM D638.

Melt index [g/10min]: It was measured after staying for 3 minutes at 230°C and a load of 10.0 kg according to ASTM D1238.

Friction noise (Dry) [dB]: A 90 Ф x 3.0 disk-shaped specimen was injected, and the two specimens were fixed to a rotating motor and rubbed at a speed of 100 rpm, while noise generated during friction was measured using a noise meter.

Friction noise (Wet) [dB]: Measure in the same way as friction noise (Dry), but spray the specimen with water at an amount of about 100 mL per minute for 10 minutes to make the specimen completely wet. measured.

Surface contact angle (°): After injecting a 90 Ф x 3.0 disk-shaped specimen and fixing it on a horizontal device, 13 μL of water droplets were dropped on the specimen to measure the static contact angle. Table 2 shows the average of the values measured 5 times for the same specimen.

Friction coefficient: A 100 x 350 x 2.0 specimen was injected according to ASTM D1894, and the static friction coefficient and the dynamic coefficient of friction of the specimen were measured.

Extrudability: The extrudability of the composition was evaluated during the extrusion operation (extrudable: O, non-extrudable: X).

[Table 2]

As can be seen from Table 2, the compositions of Examples 1 to 3 exhibited mechanical properties (tensile strength, tensile elongation, melt index, extrudability) at a level suitable for blow molding, and at the same time, low friction in both dry and wet conditions. modulus and good low noise characteristics (low friction noise). On the other hand, the compositions of Comparative Examples 1 and 3 to 7 exhibited increased coefficient of friction and friction noise compared to Examples in both dry and wet conditions, and the composition of Comparative Example 2 exhibits die-swelling during extrusion. Extrusion was impossible due to the phenomenon. In addition, the composition of Comparative Example 8 had too high a melt index, which could indicate parison sagging during blow molding, and the composition of Comparative Example 9 had a too low melt index and poor moldability.

From this, the thermoplastic elastomer resin composition of the present invention realizes mechanical properties suitable for blow molding, and at the same time exhibits a low coefficient of friction and excellent low-joint properties in a wet environment as well as in a dry environment. It can be seen that the friction coefficient and low noise are particularly suitable for the manufacture of blow molded products for automobiles (eg, constant velocity joint boots, etc.).

Claims (10)

(1) a thermoplastic polyester-based elastomer resin;
(2) polytetrafluoroethylene as a fluorinated hydrocarbon additive; and
(3) an isocyanurate compound of the following structure as a reactive additive;
Based on 100% by weight of the total composition, including 0.5 to 3% by weight of the fluorinated hydrocarbon additive, and 0.5 to 1.0% by weight of the reactive additive,
Thermoplastic polyester-based elastomer resin composition:

. The thermoplastic resin according to claim 1, wherein the thermoplastic polyester-based elastomer resin comprises a polymer unit derived from an aromatic dicarboxyl compound and a diol compound as a hard segment, and a polymer unit derived from a polyalkylene oxide as a soft segment. A block copolymer, a thermoplastic polyester-based elastomer resin composition. A molded article comprising the thermoplastic polyester-based elastomer resin composition of claim 1 or 2. The molded article according to claim 3, wherein the molded article is produced by blow molding. The molded article according to claim 3, wherein the molded article is an automobile part. The molded article according to claim 5, wherein the automobile part is a constant velocity joint boot. delete delete delete delete