KR20080062580A - Thermoplastic elastomer resin composition having impact resistance and high hardness at a low temperature - Google Patents

Abstract

A thermoplastic elastomer resin composition is provided to improve impact resistance and high hardness at a low temperature and to enhance abrasion resistance. A thermoplastic elastomer resin composition comprises 50-90 parts by weight of a polyether ester elastomer having a Shore hardness of 40-60 D; and 10-50 parts by weight of polyurethane. Preferably the polyether ester elastomer is a block copolymer comprising a hard segment comprising a dicarboxylic acid and a diol as a polymerization unit, and a soft segment comprising a dicarboxylic acid and a polyalkylene oxide as a polymerization unit.

Description

Thermoplastic elastomer resin composition having impact resistance and high hardness at a low temperature}

The present invention relates to a thermoplastic elastomer resin composition having impact resistance and high hardness in a low temperature environment, including a thermoplastic ether resin composition having a high surface hardness and surface light, including a polyetherester elastomer and a polyurethane having a specific shore hardness. It is about.

In real life, polyurethane materials are used steadily in the surrounding environment, and have been verified for their stability and performance as materials, and their use is expanding. In particular, polyurethane has an incidence as a flexible and good elastic material at room temperature, and commercial products using the properties are commercially available even at low temperatures. However, polyurethane has the characteristics that the low-temperature impact value rapidly decreases with increasing hardness, while the low-temperature impact strength of the urethane is maintained at low hardness, while the low-temperature impact strength is rapidly decreased at high hardness, and thus the friction characteristics and flexibility of the urethane are high. There is a limit in utilizing characteristics at high hardness.

In order to solve the disadvantages of the polyurethane, a method of reinforcing a low temperature impact modifier, a method of adding a plasticizer, or a method of lowering the crystallinity is used. Can not get even characteristics.

Polyetherester elastomer (Polyetherester elastomer) is excellent in low temperature impact, oil resistance and chemical resistance, and is widely used in various industries including electric and electronic fields, and has a relatively high impact resistance against low temperature impact at high hardness than urethane. However, the polyether ester elastomer has a high recovery at low elongation in structure, but has a low recovery at high elongation. In addition, the polyether ester elastomer is largely damaged by an external repeated impact, but in the case of urethane, the degree of damage is weaker than that of the polyether ester elastomer.

In order to improve the disadvantages of the polyether ester elastomer, US Patent No. 3,880,976 discloses a method of improving the crystallinity of the polyether ester elastomer and changing the soft segment, but does not exhibit wearability or elastic recovery properties such as urethane. In addition, U.S. Patent No. 4,013,624 discloses a method of synthesizing a thermoplastic copolymer by adding a crosslinking agent which acts as a chemical crosslinking agent due to a large number of hydroxyl groups, but this method takes a short time to synthesize the crosslinking agent. There is a problem of remaining and weakening the thermal properties of the resin.

As such, it is required to develop a thermoplastic elastomer resin composition which not only satisfies both high hardness and low temperature impact resistance by complementing each disadvantage of the polyurethane and the polyether ester elastomer, but also reduces the amount of wear.

The present invention is to maintain the properties of the existing thermoplastic elastomer elastomer intact in order to improve the problems of the above-mentioned polyether ester elastomer, but the thermoplastic elastomer resin composition having abrasion resistance and impact resistance by external force even at high hardness through mixing with polyurethane The purpose was to gain.

That is, the present invention improves the wearability and high elongation low recovery elasticity of the polyether ester elastomer and at the same time compensates for the disadvantages of the high hardness low temperature and low impact of the polyurethane resin, the performance of the elastic body and the existing polyether elastomer elastomer It is an object to provide a thermoplastic elastomer composition having excellent high hardness, low temperature high impact and wear resistance by effectively expressing the properties of the urethane in the composition.

The present invention relates to a thermoplastic elastomer resin composition comprising 50 to 90 parts by weight of polyetherester elastomer having a Shore hardness of 40D to 60D and 10 to 50 parts by weight of polyurethane having a Shore hardness of 50D to 75D.

The polyether ester elastomer used in the thermoplastic resin composition according to the present invention is a thermoplastic polymer that is block copolymerized into a hard segment composed of short-chain polyester and a soft segment composed of long-chain polyester. to be. In the present invention, the hard segment includes dicarboxylic acid (dicarboxylic acid) and diol (di-ol) as the polymer unit, the soft segment is dicarboxylic acid (polycarboxylic acid) and polyalkylene oxide (polyalkylene oxide) as the polymer unit ). The ends of the polyether portions of the long chain polyesters that make up the soft segments are connected to the dicarboxylic acids via ester linkages so that the soft and hard segments are connected to each other. In this specification, a soft segment is defined to include an ester linkage at the end of its polyether moiety.

Accordingly, in the present invention, the polyether ester elastomer is a dicarboxylic acid, preferably an aromatic dicarboxylic acid or an ester forming derivative thereof; Diols, preferably aliphatic diols or alicyclic diols having 2 to 10 carbon atoms; And three components of the polyalkylene oxide are copolymerized.

The aromatic dicarboxylic acid is preferably at least one selected from the group consisting of terephthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, dimethyl terephthalate and diethyl terephthalate.

The diol is at least one diol selected from the group consisting of aliphatic diols and alicyclic diols having 2 to 10 carbon atoms such as the following Chemical Formula 1.

[Formula 1]

HO- (CH ₂ ) _m -OH

Wherein m is an integer from 2 to 10.

Preferred examples of the diol used in the present invention include aliphatic diols such as ethylene glycol, 1,3-propylenediol, 1,4-butanediol, pentamethylene glycol, hexamethylene glycol, and 1,4-cyclohexanedimethanol Alicyclic diols. Among the diols, aliphatic is more preferred, and ethylene glycol (m = 2) or 1,4-butanediol (m = 4) is most preferred.

The polyalkylene oxide is preferably a compound represented by the following formula (2).

[Formula 2]

HO-[-(CH ₂ ) _{m '} O-] _n -H

Wherein m 'is an integer from 2 to 10, n is an integer from 1 to 70.

Examples of preferred polyalkylene oxides include polyoxyethylene glycol, polyoxypropylene glycol (PEG), polyoxytetramethylene glycol (PTMG), and polyoxyoctamethylene glycol (Polyoxyoctamethylene glycol). ). Among them, PTMG (m '= 4) or PEG (m' = 2) is more preferable. When the long chain diol component PTMG is used, the elasticity and elasticity of the polyether ester elastomer, low permanent compressive strain, and low temperature impact strength exhibit particularly excellent characteristics. PEG exhibits low elastic recovery, but shows excellent performance in heat resistance.

The preferred content of the polyalkylene oxide used in the present invention is 20 to 80 parts by weight based on 100 parts by weight of the polyetherester elastomer. If the polyalkylene oxide content is less than 20 parts by weight, the hardness of the composition of the present invention becomes too high, and if it is 80 parts by weight or more, there is a problem in that the time is long during synthesis.

Preferred molecular weight of the polyalkylene oxide is 200 to 3,000. At this time, if the molecular weight is less than 200, the function of the soft segment is insufficient, and the elasticity of the material is small. If the molecular weight is 3,000 or more, the reaction time during processing is considered.

Most preferred polyetherester elastomers according to the invention are block copolymerized into hard segments comprising polybutylene terephthalate as polymerized units and soft segments comprising polytetramethylene glycol (PTMG) as polymerized units.

Polyetherester elastomers that can be used in the present invention can be prepared through melt polymerization, which generally consists of two stages: oligomerization and polycondensation. The oligomerization reaction is reacted at 140 ° C. to 215 ° C. for 3 to 4 hours, and the polycondensation reaction may be prepared by proceeding with a step of reducing the pressure from 760torr to 0.3torr for 4 to 5 hours at 210 ° C to 250 ° C. .

It is preferable that the Shore hardness of the polyether ester elastomer used by this invention is 40D-60D. Here, when the Shore hardness is less than 40D, the composition loses the clamping force against external force, and thus the use of the composition is limited. When the Shore hardness exceeds 60D, it is difficult to obtain high hardness, low temperature, high impact strength and hardly develop wear resistance. Can not do it.

Polyurethanes, preferably thermoplastic polyurethanes, used in the thermoplastic resin composition according to the present invention, like the polyetherester elastomer, have long segments of soft chains in the molecule, and short chains of urethanes comprise hard segments. Polyurethane thermoplastic elastomer is a thermoplastic elastic material having a urethane bond formed in a polymer main chain by adding a diol and a diisocyanate group.

Preferably, in the present invention, the hard segment of the polyurethane may include the diol of the formula (1) as the polymer unit, as the polyether ester elastomer, and the soft segment may include the polyalkylene oxide of the formula (2) as the polymer unit. . More preferably, 1,4-butanediol can be used as a polymer unit for a hard segment, and polytetramethylene glycol (PTMG) of molecular weight 250, 500, 1000 or 2000 can be used as a polymer unit for a soft segment.

Due to the nature of the material, it has transparency, flexibility, and elastic recovery ability, so it is a marketable substitute for vulcanized rubber which cannot be recycled, and it is a material commonly seen in the surroundings.

The polyurethane that can be used in the present invention can be produced by addition polymerization of an alcohol having an active hydroxyl group (-OH) and an isocyanate having an isocyanate group (-N = C = O). In general, isocyanate functional groups can easily react with various functional groups having active hydrogen because of their high reactivity.

Shore hardness of the polyurethane used in the present invention is preferably 50D to 75D, more preferably 53D to 68D. Here, when the Shore hardness is less than 50D, it does not exhibit high hardness characteristics, and when the Shore hardness exceeds 75D, it is not preferable because it does not exhibit the low temperature high impact characteristic value to be obtained by the composition.

As described above, in the polyetherester elastomer, two structures, a hard segment and a soft segment, form a molecule so that the crystal part of the hard segment plays an elastic role at room temperature instead of the vulcanized part of the rubber. It becomes an easy molten state. The combination of the crystalline portion and the soft segment portion of the hard segment portion causes the polyetherester elastomer to exhibit elastic properties. Such physical crosslinking does not fall short of the elasticity characteristics and the wear characteristics of the polyurethane.

Urethane, on the other hand, does not have low-temperature, high-impact strength characteristics at high hardness unlike polyetherester elastomers. Thus, by mixing these two components, polyurethane and polyetherester elastomer, according to the present invention, the low impact strength of the polyurethane is prevented from being lowered at low temperature impact strength and the amount of wear of the polyetherester elastomer is reduced.

In the thermoplastic elastomer resin composition according to the present invention, the content of each component preferably includes 50 to 90 parts by weight of polyetherester elastomer and 10 to 50 parts by weight of polyurethane. When more than 90 parts by weight of polyether ester elastomer is used, it is difficult to express the wear resistance required by the present patent, and when less than 50 parts by weight is used, it does not exhibit low temperature high impact strength. Polyurethane is also difficult to obtain the wear resistance of the composition when used in less than 10 parts by weight, and when used in excess of 50 parts by weight, it is difficult to obtain high hardness low temperature high impact strength.

The thermoplastic elastomer resin composition according to the present invention may be prepared by mixing and melting the polyether ester elastomer and polyurethane in an extruder. At this time, the melt blend temperature of the polyurethane and the polyether ester elastomer is preferably a temperature at which these components melt. In general, the kneading and mixing parts of the extruder are 20-30 ° C higher than the resin melting temperature. The processing temperature range of elastomer only is 200 ~ 220 ℃. However, when the lubricant is added, the processing temperature is slightly lowered to 190-210 ° C. In addition, after kneading and mixing, the temperature is preferably set to a melting temperature of -10 to + 10 ° C.

The elastomer resin composition according to the present invention may further include an additive such as a filler or a pigment.

Here, the filler may be used, for example, by selecting one or more of an antioxidant, a UV stabilizer, and a lubricant component for each of 100 parts by weight of the resin composition. When the filler is used in less than 0.001 parts by weight, the thermal stability, UV stability and mold release properties are lowered, and when used more than 1 part by weight of the overuse due to the rubber properties after the processing molding comes out.

In addition, as the pigment, carbon black, titanium oxide, zinc oxide, azo pigments, nitro pigments, lake pigments and the like can be used.

Hereinafter, the present invention will be described in detail with examples. However, the present invention is not limited by the examples.

Example 1-4

Compounds were prepared by mixing polyetherester elastomers and polyurethanes having Shore hardness described in the 'Examples' column of Table 1 in each of the weight ratios described. Polyetherester elastomers were used by Samyang Corp. TRIEL 5400NA (hardness 40D), 5550NA (hardness 55D) and 5650NA (hardness 65D), and polyurethanes were NEOTHANE 5095A (hardness 45D), 5098A (hardness 53D) and 5068D (hardness) of Hyosung Chemex. 68D) product was used.

These two resins were blended using a twin screw compressor (ZSK 25). The resin processing temperature was 210-220 degreeC, and it extruded and the injection molding was carried out at 220-230 degreeC. Drying before molding was dried for 2 to 3 hours at 90 ℃ to remove moisture. After injection, after 2 days, the amount of wear, hardness, and low temperature impact strength were measured, and the results are shown in Table 2.

(Wear amount measurement)

      According to ASTM D1044 it was measured under the conditions of H18, 1kg, 1000cycles.

(Hardness measurement)

      It was measured by Shore D type by the method of ASTM D2240.

(Low temperature impact strength measurement)

     IZOD impact strength was measured by the method of ASTM D256.

Comparative Example 1-5

The thermoplastic elastomer resin composition was prepared by melt kneading the polyetherester elastomer having a Shore hardness and the polyurethane component described in the 'Comparative Examples' column of Table 1 at the weight ratios described in the same manner as in the Examples.

TABLE 1

TABLE 2

As can be seen in Table 2, it can be seen that the thermoplastic elastomer resin composition obtained by the present invention is a material having excellent low temperature and high impact strength at high wear properties and high hardness.

The thermoplastic elastomer resin composition obtained by extrusion mixing a polyether ester elastomer and a polyurethane according to the present invention exhibits excellent high hardness low temperature low impact resistance and wear resistance. The composition according to the present invention, which complements the abrasion of the polyether ester elastomer and the high hardness low temperature high impact of polyurethane, further expands the materials that have previously required low temperature impact at low hardness, thereby preventing impact even at high hardness and low temperature. It is expected to be made of a material that can withstand the use of materials that require low impact and low impact at high hardness, such as winter leisure and sporting goods or vehicle-related parts.

Claims (9)

A thermoplastic elastomer resin composition comprising 50 to 90 parts by weight of a polyetherester elastomer having a Shore hardness of 40D to 60D and 10 to 50 parts by weight of a polyurethane having a Shore hardness of 50D to 75D. The polyether ester elastomer according to claim 1, wherein the polyether ester elastomer is block copolymerized into a hard segment including dicarboxylic acid and diol as a polymer unit and a soft segment including dicarboxylic acid and polyalkylene oxide as a polymer unit. Characterized in that the composition. The composition of claim 2, wherein the dicarboxylic acid is at least one member selected from the group consisting of terephthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, dimethyl terephthalate and diethyl terephthalate. The composition according to claim 2, wherein the diol is at least one member selected from the group consisting of aliphatic diols and alicyclic diols having 2 to 10 carbon atoms. The diol of claim 4, wherein the diol is selected from the group consisting of ethylene glycol, 1,3-propylenediol, 1,4-butanediol, pentamethylene glycol, hexamethylene glycol, and 1,4-cyclohexanedimethanol A composition characterized in that the species or more. The composition of claim 2, wherein the polyalkylene oxide is a compound represented by the following Chemical Formula 2: [Formula 2] HO-[-(CH ₂ ) _{m '} O-] _n -H Wherein m 'is an integer from 2 to 10, n is an integer from 1 to 70. The composition according to claim 6, wherein the polyalkylene oxide has a molecular weight of 200 to 3,000. The composition of claim 6 comprising 20 to 80 parts by weight of polyalkylene oxide based on 100 parts by weight of polyetherester elastomer. The composition according to claim 6, wherein the polyalkylene oxide is at least one selected from the group consisting of polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol and polyoxyoctamethylene glycol.