KR20200090681A - Thermoplastic elastomer resin composition - Google Patents

Abstract

Disclosed are: a thermoplastic elastomer resin composition comprising a thermoplastic elastomer resin and, as a reactive additive, a compound containing one or more isocyanurate groups; and a molded product comprising the same.

Description

Thermoplastic elastomer resin composition {Thermoplastic elastomer resin composition}

The present invention relates to a thermoplastic elastomer resin composition, and more particularly, to a thermoplastic elastomer resin composition in which the amount of outgas generated during injection molding is reduced.

Thermoplastic elastomer resins are used in various forms across industries such as electrical and electronic materials, biomaterials, and automotive materials based on excellent heat resistance, chemical resistance, and durability, and are replacing existing materials. In particular, thermoplastic polyester-based elastomer resins are used in automobile parts in constant velocity joint boots, gearbox bellows, and air ducts. These automobile parts are manufactured by blow molding, and since the resin is produced through a blow process in a molten state, the resin in the molten state must have a high melt viscosity and melt tension, and the parison form must be maintained during extrusion blow. .

Reactive additives have been used to realize the properties of these blow molding materials. When a reactive additive is used, physical properties for blow molding can be realized, as well as excellent heat resistance to a molded product.

However, conventional reactive additives have a problem that unreacted reactive additives may remain in the molded product upon reaction extrusion. Residual reactive additives generate outgases during blow molding, and they gradually accumulate in the mold, and as the production process continues, mold deposition occurs. Due to the materials deposited in the mold, problems of workability such as occurrence of injection defects and an increase in the number of cleaning molds are caused.

Therefore, there is a need to develop a thermoplastic elastomer resin composition for blow molding in which mold outflow problems are improved due to less outgas generation.

The problem to be solved by the present invention is to provide a thermoplastic elastomer resin composition having less outgas generation and improved injection molding workability.

In order to solve this problem, according to an aspect of the present invention, a thermoplastic elastomer resin composition of the following embodiment is provided.

The first embodiment,

Based on 100 parts by weight of the composition,

A thermoplastic elastomer resin and a compound containing at least one isocyanurate group as a reactive additive in a weight ratio of 97.8:0.3 to 97.1:1.0,

It relates to a thermoplastic elastomer resin composition further comprising 0.05 to 1 part by weight of an antioxidant and 0.1 to 5 parts by weight of a surface modifier.

In a second embodiment, in the first embodiment,

The thermoplastic elastomer resin relates to a thermoplastic elastomer resin composition comprising a thermoplastic polyester elastomer (TPEE), a thermoplastic styrene-butadiene elastomer (TPE-S), a thermoplastic polyurethane (TPU), or two or more of them.

The third embodiment, in the first embodiment or the second embodiment,

The thermoplastic elastomer resin is a thermoplastic polyester elastomer (TPEE),

A hard segment in which the thermoplastic polyester-based elastomer comprises a polymerization unit derived from an aromatic dicarboxyl compound and a diol; And a soft segment comprising a polymerized unit derived from polyalkylene oxide.

The fourth embodiment, in the third embodiment,

The aromatic dicarboxyl compound comprises terephthalic acid, isophthalic acid, 1,5-dinaphthalene dicarboxylic acid, 2,6-dinaphthalene dicarboxylic acid, dimethyl terephthalate, dimethyl isophthalate or a mixture of two or more of these ;

The diol comprises ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol or a mixture of two or more of these;

The polyalkylene oxide relates to a thermoplastic elastomer resin composition comprising polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, or a mixture of two or more of them.

The fifth embodiment, in the third or fourth embodiment,

The thermoplastic polyester elastomer is branched by a branching agent, and the branching agent relates to a thermoplastic elastomer resin composition comprising glycerol, pentaerythritol, neopentyl glycol, or a mixture of two or more of these.

The sixth embodiment according to any one of the first to fifth embodiments,

The compound containing one or more isocyanurate groups is hexamethylene diisocyanate-isocyanurate, isopron diisocyanate-isocyanurate, toluene diisocyanate-isocyanurate, 4,4-cyclohexanebismethylisocyanate -Isocyanurate, 4,4'-dicyclohexylmethanediisocyanate-isocyanurate, methylenediphenyldiisocyanate-isocyanurate, or a thermoplastic elastomer resin composition comprising a mixture of two or more thereof.

The seventh embodiment according to any one of the first to sixth embodiments,

The surface modifier relates to a thermoplastic elastomer resin composition which is a silicone resin. The eighth embodiment further comprises, in any one of the first to seventh embodiments, an additive comprising a light stabilizer, a heat stabilizer, a lubricant, a reinforcing agent, a dye, a pigment, or a mixture of two or more thereof. It relates to a thermoplastic elastomer resin composition.

The ninth embodiment relates to a molded article comprising the thermoplastic elastomer resin composition of any one of the first to eighth embodiments.

According to an embodiment of the present invention, it relates to a thermoplastic polyester-based elastomer resin composition having improved outgassing workability due to less outgas generation, and a high-viscosity product suitable for blow molding using a pre-commercialized ester-based elastomer. Can produce. In addition, it is possible to expect an effect of improving the workability of blow molding, such as preventing mold deposition by reducing outgas, a problem of reaction extrusion, and preventing injection failure due to mold deposition.

In addition, according to one embodiment of the present invention, while improving the mold deposition problem due to the reduction of outgas generation, the mechanical properties are maintained to be equal to or higher than the prior art, such as blow-molded products of constant velocity joint boots, gearbox bellows and air ducts, etc. It can be used for manufacturing.

Hereinafter, the present invention will be described in detail. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to ordinary or lexical meanings, and the inventor appropriately explains the concept of terms to explain his or her invention in the best way. Based on the principle that it can be defined, it should be interpreted as meanings and concepts consistent with the technical spirit of the present invention.

Therefore, the configuration shown in the embodiments described herein is only one of the most preferred embodiments of the present invention and does not represent all of the technical spirit of the present invention, and various equivalents that can replace them at the time of this application It should be understood that there may be and variations.

In addition, "part by weight" described in this specification means a weight ratio between components included in the thermoplastic elastomer resin composition.

Thermoplastic elastomer resin composition according to an aspect of the present invention, based on 100 parts by weight of the composition, the thermoplastic elastomer resin 95 to 99 parts by weight; And 0.2 to 2.5 parts by weight of a compound containing at least one isocyanurate group as a reactive additive.

The thermoplastic elastomer resin composition according to an embodiment of the present invention may include a thermoplastic elastomer (TPE) resin as a base resin.

As the thermoplastic elastomer resin, a common thermoplastic elastomer resin may be used alone or in combination of two or more.

Examples of the thermoplastic elastomer resin include, for example, a thermoplastic polyester elastomer (TPEE) (including a thermoplastic copolyester elastomer), a thermoplastic styrene-butadiene elastomer (TPE-S), a thermoplastic polyurethane (TPU), or these. It may include a mixture of two or more.

According to one embodiment of the present invention, a thermoplastic polyester-based elastomer (TPEE) may be used as the thermoplastic elastomer resin, and the thermoplastic polyester-based elastomer may be conventionally used, and the hardness may be adjusted by containing a plasticizer. It may be, but the hardness of the thermoplastic polyester-based elastomer is not particularly limited, and may be variously selected depending on the product to be applied.

The thermoplastic polyester-based elastomer is a thermoplastic polymer that is block-copolymerized with a hard hard segment and a soft soft segment.

According to an embodiment of the present invention, the hard segment may include an aromatic dicarboxyl compound and a polymerization unit derived from a diol, and the soft segment may include a polymerization unit derived from a polyalkylene oxide.

The aromatic dicarboxyl compounds include terephthalic acid (TPA), isophthalic acid (IPA), 1,5-dinaphthalene dicarboxylic acid (1,5-Dinaphthalenedicarboxylic Acid, 1,5-NDCA), 2,6-Dinaphthalene dicarboxylic acid (2,6-Dinaphthalenedicarboxylic Acid, 2,6-NDCA), Dimethyl Terephthalate (DMT), Dimethyl Isophthalate (Dimethyl Isophthalate) or a mixture of two or more of these It can be, and specifically, dimethyl terephthalate can be used.

As the diol, a linear aliphatic diol having 2 to 8 carbon atoms or a cyclic aliphatic diol having 3 to 8 carbon atoms may be used, for example, ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1, It may include 6-hexanediol, 1,4-cyclohexanedimethanol or a mixture of two or more of them, and specifically, 1,4-butanediol may be used.

The polyalkylene oxide may include polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol (PTMEG), or a mixture of two or more of them, in detail Polyoxytetramethylene glycol can be used.

According to one embodiment of the present invention, the thermoplastic polyester-based elastomer may be branched by a branching agent, which increases the melt tension to improve the stability of the strand during production of the polyester-based elastomer. In order to improve, and thereby increase productivity.

The branching agent may include, for example, glycerol, pentaerythritol, neopentylglycol, or a mixture of two or more of them, and specifically, glycerol may be used.

The thermoplastic polyester-based elastomer according to an embodiment of the present invention may be generally prepared through melt polymerization consisting of two steps of an oligomerization reaction and a polycondensation reaction, and may preferably be a branched thermoplastic polyester-based elastomer. have.

In one embodiment of the present invention, the branched thermoplastic polyester-based elastomer, after the above components are introduced into the reactor, a suitable catalyst (for example, tetra-n-butoxy titanium (TBT) ), in the presence of an oligomerization reaction and a polycondensation reaction may be prepared through melt polymerization, wherein the oligomerization reaction may be carried out at 140 to 215° C. for 3 to 4 hours, and the polycondensation reaction may It may be carried out in a process of stepwise decompression from 760 torr to 0.3 torr at 210 to 250°C for 4 to 5 hours.

In one embodiment of the present invention, when considering mechanical strength and flexibility, the soft segment content in the thermoplastic polyester-based elastomer is 5 to 75% by weight based on 100% by weight of the total of the thermoplastic polyester-based elastomer, specifically 30 It may be from 70 to 70% by weight. When the soft segment content in the polyester-based elastomer satisfies this range, the hardness of the thermoplastic polyester-based elastomer is not excessively high, flexibility is improved, and high heat resistance performance can be realized.

According to an embodiment of the present invention, the intrinsic viscosity of the polyester-based elastomer may be 1.7 to 2.2 dl/g, and specifically 1.9 to 2.0 dl/g.

The thermoplastic elastomer resin composition of the present invention contains a compound containing at least one isocyanurate group as a reactive additive in order to increase melt viscosity and melt tension to enable blow molding.

Specifically, the isocyanurate group is made by combining three isocyanate compounds, and has excellent thermal stability. Compared to a conventional isocyanate compound having two or fewer reactive groups, the isocyanurate group has more reactive groups, and thus can form more chains and urethane bonds of the thermoplastic elastomer resin, thereby providing better properties in terms of molecular weight increase. Visible, and may play a role in improving thermal stability. As a result, as a compound containing one or more isocyanurate groups is used as a reactive additive, it is possible to improve mechanical properties and lower viscosity to make blow molding possible.

In addition, since the isocyanurate group included in the reactive additive of the present invention has one more isocyanate group compared to the conventional isocyanate compound, it is less likely that unreacted substances escape by performing more reactions with the thermoplastic elastomer resin, and isocyanu Since the compound having a rate group shows excellent thermal stability by itself, it can be decomposed at the time of injection to reduce the possibility of gas deposition and mold deposition.

The compound usable as the reactive additive may be used without limitation as long as it contains one or more isocyanurate groups. For example, compounds containing one or more isocyanurate groups include hexamethylene diisocyanate-isocyanurate, isoprondiisocyanate-isocyanurate, toluene diisocyanate-isocyanurate, 4,4-cyclohexane Bismethylisocyanate-isocyanurate, 4,4'-dicyclohexylmethanediisocyanate-isocyanurate, methylenediphenyldiisocyanate-isocyanurate, or mixtures of two or more of these. Does not work.

The thermoplastic elastomer resin composition of the present invention, based on 100 parts by weight of the composition, includes 95 to 99 parts by weight of the thermoplastic elastomer resin, and 0.2 to 2.5 parts by weight of the reactive additive.

In one embodiment of the present invention, the content of the reactive additive may be 0.3 to 2 parts by weight, more specifically 0.5 to 1 part by weight, based on 100 parts by weight of the composition. If the content of the reactive additive is less than 0.2 parts by weight based on 100 parts by weight of the composition, the melt viscosity is low, which makes it difficult to use as a blow molding material, and when it exceeds 2.5 parts by weight, outgas generation is increased, resulting in mold deposition and injection molding. Workability may be poor.

The thermoplastic elastomer resin composition of the present invention may further include an antioxidant in order to prevent the thermoplastic elastomer resin from being deteriorated and oxidized in a high temperature injection molding process.

The type of the antioxidant is not particularly limited, and antioxidants commonly used in this field can be used without limitation. For example, hindered amin antioxidant, hindered phenol antioxidant, phosphite antioxidant, amide antioxidant, thioester oxidation An antioxidant or a mixture of two or more of these may be used as an antioxidant, but is not limited thereto.

More specifically, 4,4'-bis(α,α-diphenylbenzyl)diphenyl amine, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate, Alternatively, a mixture of two or more of them may be used as an antioxidant, but is not limited thereto.

The content of the antioxidant, based on 100 parts by weight of the composition, may be 0.05 to 1 part by weight, specifically 0.1 to 0.5 part by weight.

In addition to the above components, the thermoplastic elastomer resin composition of the present invention may further include one or more additives commonly used in the thermoplastic elastomer resin composition. The additive may be, for example, a light stabilizer, a heat stabilizer, a surface modifier, a lubricant, a reinforcing agent, a dye, a pigment, or a mixture of two or more of these, but is not limited thereto. Among these, silicone resins are examples of surface modifiers, but are not limited thereto. The surface modifier is compounded with a thermoplastic elastomer resin and serves to protect the surface as it migrates to the surface of the injection product when injected, and at the same time, it has a better effect of falling off the injection mold, thereby improving moldability.

The content of the additive is not particularly limited, and can be used without limitation in a range that does not impair the physical properties desired by the present invention. For example, the content of the additive may be 0.1 to 5 parts by weight, in particular 0.5 to 3 parts by weight, based on 100 parts by weight of the composition, but is not limited thereto.

The thermoplastic elastomer resin composition according to an embodiment of the present invention may be prepared by adding the thermoplastic elastomer resin, a reactive additive, and optionally an antioxidant and optional additives described above to the extruder, mixing and extruding in the extruder.

The extruder may be a twin-screw or single-screw extruder, and the extruder L/D (length/diameter) may be 20 to 35, but is not limited thereto.

As the extrusion conditions, an extruder temperature of 180 to 220°C, RPM 150 to 350 may be used, but is not limited thereto.

The thermoplastic elastomer resin composition of the present invention prepared as described above has a high melt viscosity and melt tension, and thus can be utilized as a blow molding material.

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

The molded article provided according to one embodiment of the present invention may be a constant velocity joint boot of a vehicle, a gearbox bellows or an air duct.

Hereinafter, examples will be described in detail to help understanding of the present invention. However, the embodiments according to the present invention can be modified in many different forms, and the scope of the present invention should not be construed as being limited to the following examples. The embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art.

[Example]

<Production of a thermoplastic polyester elastomer resin>

Preparation Example 1: Preparation of TPEE of Shore Hardness D-40

Dimethyl terephthalate (DMT) 34.60 parts by weight, 1,4-butanediol 25.0 parts by weight, molecular weight 2,000 polyoxytetramethylene glycol (PTMEG) 40.20 parts by weight and glycerol 0.065 parts by weight into an oligomerization reactor and tetra-n-part as a catalyst 0.025 parts by weight of Toxy Titanium (TBT) was added. The reaction temperature was raised from 140°C to 215°C for 120 minutes, and the reaction was performed for the remaining 120 minutes while maintaining 215°C. The amount of methanol, which is the reaction effluent, was converted into a reaction rate, and the reaction was terminated when the reaction rate was 99% or more. Subsequently, a polycondensation reaction was performed by adding 0.04 parts by weight of catalyst TBT and 0.07 parts by weight of heat stabilizer (Irganox 1010). The polycondensation reaction was carried out by raising the temperature from 215°C to 250°C for 120 minutes, and reacting for the remaining 120 minutes while maintaining 250°C. At this time, the pressure was reduced from 760 tor to 0.3 torr for 1 hour, and the remaining 3 hours were under vacuum conditions of 0.3 torr or less, and the final reduced pressure was adjusted to 0.3 torr or less to prepare TPEE of Shore Hardness-D 40. The intrinsic Viscosity of the TPEE thus prepared was 1.7 dl/g measured under a solvent of phenol/tetrachloroethane = 50/50.

<Preparation of thermoplastic elastomer resin composition>

Examples 1 to 4 and Comparative Examples 1 to 5

The resin composition of each Example and Comparative Example was prepared with the composition shown in Table 1 below. The raw materials made of the TPEE resin and additives prepared in Preparation Example 1 were simultaneously put into a twin screw extruder and extruded. The temperature of the extruder was extruded by setting the hopper part to 150°C and the rest to 190°C to 230°C, twin screws (L/D=40) were used, the diameter of the die was 26phi, and a kneading block block) was used. The feed rate of the resin was 10 kg/hr to 12 kg/h, and the rotational speed of the extruder screw was 150 rpm to 200 rpm.

Subsequently, the resin composition subjected to the extrusion process was subjected to a cooling process in a cooling bath, and then pelletized to prepare pellets of the thermoplastic elastomer resin composition.

<ingredient explanation>

TPEE: Thermoplastic polyester elastomer prepared in Preparation Example 1

Reactive additive: hexamethylene diisocyanate (HDI) isocyanurate (trimer) (TLA-100, manufactured by Asahikasei (manufactured))

Naphthalenediisocyanate: HARTDUR 115 (Johnson fine chemical (manufactured))

Silicone resin: MB50-010 (Dow Corning (manufactured))

Heat stabilizer: NAUGAURD 445 (Kemtura (manufactured))

Antioxidant 1: Sulfur-based antioxidant (Irganox 412S, BASF (manufactured))

Antioxidant 2: Phenolic Antioxidant (SONG 1076, Songwon Industrial Co., Ltd.)

The properties of the thermoplastic elastomer resin composition prepared as described above were measured by measuring the following items, and the results are shown in Table 2 below.

(1) Tensile strength: evaluated according to ASTM D638.

(2) Tensile elongation: It was evaluated according to ASTM D638.

(3) Modulus: evaluated according to ASTM D638.

(4) Melt index (Melt index): measured in accordance with ASTM D1238 at a temperature of 230° C. and a load condition of 10.0 kg for 3 minutes.

(5) Out gas: Through GC/MS analysis, gases generated when GC/MS analysis was performed on a sample of the same weight at 230° C. were identified and measured by calculating the total out gas area (total out gas amount).

(6) Mold deposition: When 50 square specimens of 8 cm × 6 cm × 6.5 mm were continuously injected, it was judged as the presence or absence of a white deposit deposited on the gas vent portion of the mold.

As described in Table 2, in Examples 1 to 4 according to the present invention, while having excellent mechanical properties such as tensile strength, tensile elongation and modulus, high melt viscosity (low melt index) is suitable as a material for blow molding In particular, it was confirmed that there was no mold deposit due to a significant reduction in outgas generation, which was a problem in the prior art.

However, in the case of Comparative Example 1 in which the content of the isocyanurate group-containing compound was small, the viscosity was too low (high melt index) and was not suitable as a blow molding material, and the content of the isocyanurate group-containing compound was excessive. In the case of Example 2, mold deposition occurred due to the occurrence of out gas, and in Comparative Examples 3 to 5 using a conventional isocyanate-based compound other than an isocyanurate group-containing compound as a reactive additive, the out gas was used even when an appropriate amount was used. There were many occurrences, and it was confirmed that mold deposition occurred.

Claims (9)

Based on 100 parts by weight of the composition,
A thermoplastic elastomer resin and a compound containing at least one isocyanurate group as a reactive additive in a weight ratio of 97.8:0.3 to 97.1:1.0,
A thermoplastic elastomer resin composition further comprising 0.05 to 1 part by weight of an antioxidant and 0.1 to 5 parts by weight of a surface modifier. According to claim 1,
The thermoplastic elastomer resin is a thermoplastic polyester resin (TPEE), a thermoplastic styrene-butadiene elastomer (TPE-S), a thermoplastic polyurethane (TPU), or a thermoplastic elastomer resin composition comprising two or more of them. According to claim 1,
The thermoplastic elastomer resin is a thermoplastic polyester-based elastomer (TPEE),
A hard segment in which the thermoplastic polyester-based elastomer comprises a polymerization unit derived from an aromatic dicarboxyl compound and a diol; And a soft segment comprising polymerized units derived from polyalkylene oxide. According to claim 3,
The aromatic dicarboxyl compound comprises terephthalic acid, isophthalic acid, 1,5-dinaphthalene dicarboxylic acid, 2,6-dinaphthalene dicarboxylic acid, dimethyl terephthalate, dimethyl isophthalate or a mixture of two or more of these ;
The diol comprises ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol or a mixture of two or more of these;
A thermoplastic elastomer resin composition wherein the polyalkylene oxide comprises polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, or a mixture of two or more of them. According to claim 3,
A thermoplastic elastomer resin composition in which the thermoplastic polyester-based elastomer is branched by a branching agent, and the branching agent includes glycerol, pentaerythritol, neopentyl glycol, or a mixture of two or more of them. According to claim 1,
The compound containing one or more isocyanurate groups is hexamethylene diisocyanate-isocyanurate, isopron diisocyanate-isocyanurate, toluene diisocyanate-isocyanurate, 4,4-cyclohexanebismethylisocyanate -Isocyanurate, 4,4'-dicyclohexylmethanediisocyanate-isocyanurate, methylenediphenyldiisocyanate-isocyanurate, or a thermoplastic elastomer resin composition comprising a mixture of two or more of them. According to claim 1,
The surface modifier is a silicone resin, a thermoplastic elastomer resin composition. According to claim 1,
A thermoplastic elastomer resin composition further comprising an additive comprising a light stabilizer, a heat stabilizer, a lubricant, a reinforcing agent, a dye, a pigment, or a mixture of two or more of them. A molded article comprising the thermoplastic elastomer resin composition of claim 1.