KR20200072610A - Polyamide resin composition having good heat resistance, abrasion resistance and elongation property - Google Patents

Abstract

The present invention relates to a polyamide resin composition having excellent long-term heat resistance, abrasion resistance and elongation and, more particularly, to a polyamide resin composition having improved long-term heat resistance suitable for applications such as a driving part cable material of an automobile, and at the same time having excellent abrasion resistance and elongation. The polyamide resin composition includes a polyamide resin, an impact modifier, a modified polyolefin, a thermoplastic elastomer, and a long-term heat-resistant stabilizer.

Description

Polyamide resin composition having good heat resistance, abrasion resistance and elongation property}

The present invention relates to a polyamide resin composition having excellent long-term heat resistance, abrasion resistance and elongation, and has an improved long-term heat resistance suitable for use as a cable material for driving parts of automobiles, and a polyamide resin composition having excellent abrasion resistance and elongation. will be.

Various technologies have been developed for the purpose of improving the elongation and impact strength of polyamide in the design of a polymer composite material useful as a cable material. Examples of such techniques include a method of including a plasticizer in a polyamide, and a method of including an impact modifier. However, it was difficult to achieve sufficient heat stability (long-term heat resistance) and abrasion resistance only by adding such a plasticizer or an impact modifier, so there was a disadvantage that the physical properties required as a cable material used in automobile driving parts and the like were not sufficiently provided.

In addition, various technologies have been developed for the purpose of improving wear resistance, for example, a method of depositing a durable film, a method of using an interfacial lubricant, metal sulfides such as MoS ₂ and polytetrafluoroethylene (PTFE), etc. There was a way to include. However, the method of depositing a film or using a lubricant could not improve the polymer itself, which is a raw material, and thus could not be seen as a fundamental solution. In addition, when the metal sulfide and PTFE were included, there was a disadvantage in that the processing of the polyamide resin composition became difficult as the content of PTFE increased, so that an amount sufficient to achieve sufficient elongation and impact strength required as a cable material was achieved. There was a limit that it could not be used. In addition, Korean Patent Registration No. 0387850 discloses a polyamide resin composition for an automobile fuel tube system including a polyamide resin, an impact modifier, and a nylon plasticizer, but this also has limitations in improving elongation, and also regarding heat stability and abrasion resistance. It was never mentioned.

Accordingly, there is a need to develop a polyamide material that overcomes these limitations and exhibits desirable properties in long-term heat resistance, abrasion resistance, and elongation.

An object of the present invention is to provide a polyamide resin composition capable of exhibiting physical properties such as excellent abrasion resistance and elongation while improving long-term heat resistance significantly to be suitable as a material for cables used in automobile driving parts and the like.

In order to solve the above technical problem, the present invention, (1) polyamide resin; (2) impact modifiers; (3) modified polyolefins; (4) thermoplastic elastomers; And (5) provides a polyamide resin composition comprising a long-term heat-resistant stabilizer.

According to another aspect of the present invention, a molded article produced by processing the polyamide resin composition of the present invention is provided.

The polyamide resin composition of the present invention comprises a thermoplastic elastomer (TPE) in addition to a polyamide resin, impact modifier, modified polyolefin, and long-term heat stabilizer, thereby eliminating or adding different additives, such as polytetrafluoroethylene (PTFE). It can have excellent long-term heat resistance as compared to the conventional polyamide resin composition, and at the same time, have properties such as abrasion resistance and elongation suitable for use as a material for cables.

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

The polyamide resin composition of the present invention includes a polyamide resin.

The polyamide resin that can be used in the present invention is not particularly limited as long as it is generally used in the art.

In one embodiment, the relative viscosity of the polyamide resin can range from 2.3 to 3.0, more specifically from 2.5 to 3.0, and even more specifically from 2.7 to 3.0. If the relative viscosity of the polyamide resin is less than 2.3, tensile strength, impact strength, and heat resistance decrease, and if the relative viscosity exceeds 3.0, fluidity may be insufficient during molding, resulting in poor extrusion molding processability.

Further, the polyamide may be homopolyamide, copolyamide, or a mixture thereof, and may be crystalline, semi-crystalline, or amorphous.

Polyamide resins that can be used in the polyamide resin composition of the present invention are nylon 6, nylon 7, nylon 8, nylon 10, nylon 2, nylon 66, nylon 69, nylon 610, nylon 611, nylon 612, nylon 6T, nylon 6 /66, nylon 6/12 and nylon 6/6T.

In one embodiment, the polyamide resin composition of the present invention may include 20 to 90 parts by weight of polyamide resin based on 100 parts by weight of the composition, more specifically 40 to 75 parts by weight, and more specifically 55 It may contain from 65 parts by weight. If the polyamide resin content in 100 parts by weight of the polyamide resin composition of the present invention is less than 20 parts by weight, there may be a problem that heat resistance and abrasion resistance are deteriorated, and if it exceeds 90 parts by weight, there may be a problem that elongation and impact strength fall.

The polyamide resin composition of the present invention also includes an impact modifier.

The impact modifier that can be used in the polyamide resin composition of the present invention is not particularly limited, but may include a rubber-modified vinyl-based copolymer. For example, the rubber-modified vinyl-based copolymer may be a rubber-modified vinyl-based graft copolymer.

The rubber-modified vinyl-based graft copolymer is 40% by weight to 95% by weight of styrene, α-methylstyrene, halogen or alkyl substituted styrene, C1 to C8 methacrylic acid alkyl esters, C1 to C8 acrylic acid alkyl esters, or mixtures thereof. % And 5% by weight of acrylonitrile, methacrylonitrile, C1 to C8 methacrylic acid alkyl esters, C1 to C8 acrylic acid alkyl esters, maleic anhydride, C1 to C4 alkyl or phenyl N-substituted maleimide or mixtures thereof 5% to 95% by weight of a monomer mixture composed of 60% to 60% by weight of butadiene rubber, acrylic rubber, ethylene/propylene rubber, styrene/butadiene rubber, acrylonitrile/butadiene rubber, isoprene rubber, ethylene-propylene-diene ternary Vinyl graft copolymer obtained by graft polymerization to 5 wt% to 95 wt% of one or a mixture thereof selected from the group consisting of copolymers (EPDM) and polyorganosiloxane/polyalkyl (meth)acrylate rubber composites Can.

The C1 to C8 methacrylic acid alkyl esters or C1 to C8 acrylic acid alkyl esters may be esters obtained from monohydryl alcohol containing 1 to 8 carbon atoms as esters of methacrylic acid or acrylic acid, respectively. Specific examples of these include methacrylic acid methyl ester, methacrylic acid ethyl ester, acrylic acid ethyl ester or methacrylic acid propyl ester, of which methacrylic acid methyl ester is particularly preferred.

Preferred examples of the rubber-modified vinyl-based graft copolymer include graft copolymerization of styrene and acrylonitrile and optionally (meth)acrylic acid alkyl ester monomers with butadiene rubber, acrylic rubber, or styrene/butadiene rubber in the form of a mixture, butadiene The thing which graft copolymerized the monomer of (meth)acrylic acid methyl ester with rubber, acrylic rubber, or styrene/butadiene rubber is mentioned. For example, the graft copolymer is ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), methyl methacrylate-butadiene-styrene (MBS), styrene-butadiene-styrene (SBS) , Styrene-butadiene rubber (SBR), ethylene-propylene rubber (EPM, EPR), ethylene-propylene-diene copolymer (EPDM), maleic anhydride modified IPM (EPM-g-MA), maleic anhydride modified EPR (EPR-g-MA), maleic anhydride modified SBS (SBS-g-MA), maleic anhydride modified IPDM (EPDM-g-MA) and ethylene vinyl alcohol copolymer (EVOH). Among them, maleic anhydride modified IPM (EPM-g-MA), maleic anhydride modified IPR (EPR-g-MA) and maleic anhydride modified IPDM (EPDM-g-MA) It may be most desirable.

When preparing the graft copolymer, the particle size of the rubber particles may be preferably in the range of 0.05 μm to 4 μm in order to improve impact strength and surface properties of the molded product.

The method for preparing the graft copolymer may be selected without limitation from methods known in the art to which the present invention pertains, and for example, any of emulsion polymerization, suspension polymerization, solution polymerization or bulk polymerization methods may be used. However, in the presence of a rubbery polymer, a method of emulsifying or bulk polymerization using a polymerization initiator by introducing the above-mentioned aromatic vinyl-based monomer may be preferable.

In one embodiment, the polyamide resin composition of the present invention, based on 100 parts by weight of the composition, may include 5 to 35 parts by weight of the impact modifier, more specifically 10 to 30 parts by weight, and more More specifically, it may include 12 to 20 parts by weight. If the content of the impact modifier in the polyamide resin composition is less than 5 parts by weight, the impact strength is somewhat improved, but sufficient impact resistance is not exhibited, sharp edges occur when damaged by impact, and sufficient elongation may not be achieved. , If it exceeds 35 parts by weight, the impact strength is greatly improved, but there may be a problem that the wear resistance is poor.

The polyamide resin composition of the present invention also includes a modified polyolefin.

Since the polyolefin resin has very low compatibility with the polyamide resin, in order to prepare a blend resin excellent in impact resistance by mixing the two resins, a modified polyolefin in which a reactor capable of reacting with a polyamide resin such as maleic anhydride is grafted It is preferred to use resin.

The modified polyolefin that can be used in the polyamide resin composition of the present invention may be selected from polyethylene resins and polypropylene resins with maleic anhydride grafted as a reactor, and polypropylene with maleic anhydride grafted may be preferred when considering heat resistance. have.

In one embodiment, the polyamide resin composition of the present invention, based on 100 parts by weight of the composition, may include the modified polyolefin in 5 to 30 parts by weight, more specifically 10 to 20 parts by weight, and more More specifically, it may include 12 to 18 parts by weight. When the content of the modified polyolefin is less than 5 parts by weight, the soft properties are somewhat improved, but sufficient soft properties may not be exhibited, and when it exceeds 20 parts by weight, the soft properties are greatly improved, but long-term heat resistance may be deteriorated, and the content of the modified polyolefin is When it is 12 to 18 parts by weight, it may exhibit particularly excellent soft properties and long-term heat resistance.

The polyamide resin composition of the present invention also includes a thermoplastic elastomer (TPE).

The TPE usable in the present invention is a thermoplastic block copolymer having a hard hard segment and a soft soft segment.

As a component for imparting a hard segment to TPE, an aromatic dicarboxylic acid, an aromatic dicarboxylate, or a combination thereof may be used, and more specifically, terephthalic acid (TPA) ), isophthalic acid (IPA), 1,5-dinaphthalenedicarboxylic acid (1,5-NDCA), 2,6-dinaphthalene dicarboxylic acid (2,6 -dinaphthalenedicarboxylic acid, 2,6-NDCA), dimethyl tephthalate (DMT), dimethyl isophthalate (dimethyl isophthalte) and combinations thereof, preferably DMT can be used.

Polyoxyalkylene glycol may be used as a component for imparting soft segments to TPE, and more specifically, polyoxyethylene glycol, polyoxypropylene glycol, and polyoxypropylene Glycol (polyoxypropyleneglycol), polyoxytetramethylene glycol (polyoxytetramethylene glycol, PTMEG) and may be selected from the group consisting of a combination thereof, preferably PTMEG may be used.

In the production of TPE, in addition to the components for the hard segments described above, a linear or cyclic aliphatic diol having 2 to 8 carbon atoms may be used. Ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol or a combination thereof may be used as the aliphatic diol, preferably 1,4-butanediol may be used.

In addition, a branching agent may be additionally used in the production of TPE in order to improve the stability of the TPE strand in the production of TPE by increasing the melting tension of the TPE, thereby increasing productivity. As the branching agent, glycerol, pentaerythritol, neopentylglycol, or a combination thereof may be used, and preferably glycerol may be used. In addition, the preparation of TPE can be carried out in the presence of a suitable catalyst, for example tetra-n-butoxy titanium (TBT).

The TPE may be prepared through melt polymerization consisting of two steps of an oligomerization reaction and a polycondensation reaction using the above-described components.

The TPE that can be used in the polyamide resin composition of the present invention preferably has Shore hardness D-30 to D-50, and more preferably Shore hardness D-35 to D-45.

In one embodiment, the polyamide resin composition of the present invention may contain 1 to 30 parts by weight of the TPE, based on 100 parts by weight of the composition, more specifically 2 to 20 parts by weight, and more specifically 3 To 10 parts by weight. If the TPE content in 100 parts by weight of the polyamide resin composition of the present invention is less than 1 part by weight, abrasion resistance may be deteriorated, and if it exceeds 30 parts by weight, impact resistance and elongation may be deteriorated.

The polyamide resin composition of the present invention also includes a long-term heat-resistant stabilizer.

Long-term heat stabilizers may include copper halides and halides of alkali metals. The copper halide may be selected from the group consisting of copper chloride, copper bromide, copper iodide, copper chloride, copper bromide, copper iodide, and combinations thereof, and the alkali metal halide is lithium chloride, lithium bromide, lithium iodide , Sodium fluoride, sodium chloride, sodium bromide, sodium iodide, potassium fluoride, potassium chloride, potassium bromide, potassium iodide and combinations thereof.

The content of the copper halide (eg, CuI) included in the long-term heat-resistant stabilizer may be 0.01 to 0.15% by weight based on the total weight of the polyamide resin composition of the present invention, and alkali metal halide (eg , KI) may be 0.02 to 0.4% by weight based on the total weight of the polyamide resin composition of the present invention. Even if the long-term heat stabilizer is contained in a small amount as described above in the polyamide resin composition of the present invention, the composition may exhibit excellent long-term heat resistance properties.

In one embodiment, the polyamide resin composition of the present invention, based on 100 parts by weight of the composition, may include a long-term heat stabilizer in an amount of 0.01 to 0.5 parts by weight, and more specifically, 0.05 to 0.2 parts by weight. If the content of the long-term heat stabilizer in 100 parts by weight of the polyamide resin composition of the present invention is less than 0.01 part by weight, there may be a problem that long-term heat stability is lowered, and if it exceeds 0.5 part by weight, there may be a problem of discoloration and elongation dropping.

The polyamide resin composition of the present invention may further include a metal sulfide.

The metal sulfide has self-lubricating properties and is not particularly limited as long as it is generally used in the art, but MoS ₂ , ZnS, Ag ₂ S, CuS, FeS, FeS ₂ , PbS, Bi ₂ S ₃ , CdS, and combinations thereof It may be selected from MoS ₂ (Molybdenum disulfide) may be particularly preferred.

In one embodiment, the polyamide resin composition of the present invention, based on 100 parts by weight of the composition, may contain 0.1 to 10 parts by weight of metal sulfide, and more specifically 2 to 8 parts by weight. If the metal sulfide content in 100 parts by weight of the polyamide resin composition of the present invention is less than 1 part by weight, abrasion resistance may be lowered, and if it exceeds 10 parts by weight, elongation and impact strength may be inferior.

The polyamide resin composition of the present invention may further include, in addition to the above-described components, additives selected from heat stabilizers, lubricants, colorants, and combinations thereof. These additives, based on 100 parts by weight of the composition, a total of 0.1 to 10 parts by weight, or 0.5 to 5 parts by weight may be further included.

The method for producing the polyamide resin composition of the present invention is not particularly limited and may be appropriately selected depending on the equipment used and other process elements. According to one embodiment of the present invention, the raw materials are mixed and introduced into the main hopper, melt-kneaded at a barrel temperature of 200 to 350°C and a kneading speed of 180 to 400 rpm, extruded, pelletized, and dried. Polyamide resin pellets may be prepared, but may not be limited thereto.

The polyamide resin composition of the present invention can exhibit excellent long-term heat resistance, abrasion resistance, and elongation as compared to a conventional polyamide resin composition by including a polyamide resin, an impact modifier, a modified polyolefin, a thermoplastic elastomer, and a long-term heat stabilizer. In addition, when the polyamide resin composition of the present invention additionally contains a metal sulfide, even though it exhibits significantly improved long-term heat resistance, elongation and abrasion resistance are not lowered, so it exhibits excellent properties in both long-term heat resistance, elongation and abrasion resistance, so that the cable part of the automobile driving part It may be particularly suitable for applications such as.

Accordingly, according to another aspect of the present invention, there is provided a molded article characterized by being produced by processing the polyamide resin composition of the present invention described above, preferably, a molded article that is a drive cable.

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

[ Example ]

<Preparation of polyamide resin composition>

Examples 1 and 2, and Comparative Examples 1 to 4

The polyamide resin composition of each Example and Comparative Example was prepared with the composition shown in Table 1 below. That is, the raw materials including polyamide, impact modifier, modified polyolefin, thermoplastic elastomer, metal sulfide, and/or long-term heat stabilizer specified in the following component descriptions are introduced into the main hopper, barrel temperature 240-310°C, kneading speed 200-350 After melt-kneading and extruding under rpm conditions, it is made into pellets by a pelletizer, and after drying the pellets in a dehumidifying dryer at 90° C. for 5 hours, finally injection molding to prepare a specimen of a polyamide resin composition for measuring physical properties. Did.

[Table 1]

<ingredient explanation>

-Polyamide 6: Nylon 6, EN 400 grade (RV 3.0), KP Chemtech

-EPDM-g-MA: KEPA 1150, Kumho

-Modified polypropylene: Polypropylene with maleic anhydride grafted (AT2867E, Mitsui chemical)

-TPE: TRIEL 5400 NA, Samyangsa (Shore hardness D-40)

-MoS ₂ : Metal sulfide (EL 4303, colloid)

-PTFE: Polytetrafluoroethylene (L-5, DAIKIN)

-CuI/KI: long-term heat stabilizer (H320, Bruggemannt)

<Measurement and evaluation of properties>

For the polyamide resin composition prepared as described above, the following property items were measured and evaluated, and the results are summarized in Table 2 below.

(1) Long-term heat resistance evaluation through tensile strength measurement: After the specimen was prepared according to ASTM D638, the initial tensile strength was measured. By aging the same specimen in an oven set to 140°C for 300 hours, taking out the specimen after 300 hours, measuring the tensile strength value in the same way, and comparing it with the initial value to calculate the retention rate (%). Long-term heat resistance evaluation was conducted.

(2) Tensile elongation: A specimen was prepared and measured according to ASTM D638.

(3) Impact strength: A specimen was prepared and measured according to ASTM D256.

(4) Abrasion resistance: A specimen was prepared according to ASTM D1894-06 to measure the dynamic friction coefficient and static friction coefficient.

[Table 2]

As can be seen from Table 2, the compositions of Examples 1 and 2 exhibited excellent mechanical properties, ie, elongation, long-term heat resistance (retention rate) and abrasion resistance, which are required as cable materials. Comparative Example 1, which did not contain a long-term heat stabilizer, had very low long-term heat resistance compared to the Example composition, and Comparative Example 2, which did not include TPE and metal sulfide, had significantly improved elongation, but had significantly lower long-term heat resistance and abrasion resistance, and included TPE. Comparative Example 3, which did not contain one modified polyolefin and metal sulfide, also had low elongation and long-term heat resistance, and Comparative Example 4, which did not include all of the modified polyolefin, TPE, and metal sulfide, significantly reduced both elongation, long-term heat resistance, and wear resistance. , Comparative Example 5, which does not contain a modified polyolefin, TPE, and a long-term heat stabilizer, but instead includes PTFE, has a significantly lower elongation and long-term heat resistance.

Accordingly, it was confirmed that the polyamide resin composition comprising the polyamide resin, impact modifier, modified polyolefin, TPE, long-term heat stabilizer and metal sulfide according to the present invention exhibits desirable properties in all aspects of elongation, long-term heat resistance and wear resistance. .

Claims (10)

(1) polyamide resins;
(2) impact modifiers;
(3) modified polyolefins;
(4) thermoplastic elastomers; And
(5) long-term heat-resistant stabilizer; containing,
Polyamide resin composition. The polyamide resin composition according to claim 1, wherein the polyamide resin has a relative viscosity of 2.3 to 3.0. The polyamide resin composition of claim 1, wherein the impact modifier is a rubber-modified vinyl-based copolymer. The method of claim 3, wherein the rubber-modified vinyl-based copolymer is ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), methyl methacrylate-butadiene-styrene (MBS), styrene- Butadiene-styrene (SBS), styrene-butadiene rubber (SBR), ethylene-propylene rubber (EPM, EPR), ethylene-propylene-diene copolymer (EPDM), maleic anhydride modified IPM (EPM-g-MA) , Maleic Anhydride Modified IP(EPR-g-MA), Maleic Anhydride Modified SBS(SBS-g-MA), Maleic Anhydride Modified IPDM(EPDM-g-MA) and Ethylene Vinyl Alcohol Copolymer Polyamide resin composition of 1 or more types selected from the group which consists of (EVOH). The polyamide resin composition according to claim 1, wherein the modified polyolefin is at least one selected from polyethylene resin grafted with maleic anhydride and polypropylene resin grafted with maleic anhydride. The polyamide resin composition according to claim 1, wherein the thermoplastic elastomer comprises a hard segment comprising an aromatic dicarboxylic acid, an aromatic dicarboxylate or a combination thereof, and a soft segment comprising a polyoxyalkylene glycol. The polyamide resin composition according to claim 1, wherein the long-term heat stabilizer comprises a copper halide and an alkali metal halide. The polyamide resin composition according to claim 1, further comprising a metal sulfide. The polyamide resin composition according to claim 8, wherein the metal sulfide is selected from the group consisting of MoS ₂ , ZnS, Ag ₂ S, CuS, FeS, FeS ₂ , PbS, Bi ₂ S ₃ , CdS and combinations thereof. A molded article produced by processing the polyamide resin composition of any one of claims 1 to 9.