KR20110057975A - Polyamide resin compositions with excellent flexibility and gasoline stability - Google Patents

Abstract

PURPOSE: A polyamide resin composition is provided to ensure excellent molding strength, flexibility and appearance, and stability to chloride and gasoline. CONSTITUTION: A polyamide resin composition comprises 30-70 weight% of polyamide resin, 1-30 weight% of polypropylene resin, 3-40 weight% of reactive compatibilizer, 1-30 weight% of softening plasticizer and 0.3-5 weight% of reaction control agent. The polyamide resin is at least one selected from the group consisting of nylon 12, nylon 6, nylon 6/12, and a resin having an amide group and a carboxyl group in a molecular structure. The softening plasticizer is at least one kind selected from the group consisting of carprolactam, lauryl lactam, toluenesulfonamide derivative, glycolate, phthalate, adipate, and phosphate.

Description

Polyamide resin compositions with excellent flexibility and gasoline stability

The present invention relates to a polyamide resin composition having excellent flexibility and gasoline stability.

Polyamide resin, commonly referred to as nylon, is a representative engineering plastic having excellent mechanical strength, abrasion resistance, heat resistance, and chemical resistance, and has been widely used in electric and automotive parts. However, the use of hoses, tubes, and molded articles requiring flexibility and chloride resistance is limited due to problems such as miscibility with flexible components, flexibility, hygroscopicity, and chloride resistance. On the other hand, polypropylene resin, which is a kind of olefin resin, is a general-purpose plastic, and is widely used in daily necessities, electric and electronic parts, automobile parts, etc. because of its excellent moldability and impact resistance, easy handling, and low price. However, the polyolefin resin has a low mechanical strength and low stability to hydrophobic solutions such as gasoline and toluene, and thus its use range has been restricted and its improvement is required.

In order to solve the above problems, a method for producing a polyamide resin showing melt strength and flexibility and excellent chloride and gasoline stability has been proposed. Conventionally, a representative method for improving the flexibility and low temperature characteristics of the polyamide resin has been a method of reinforcing the elastomer in the polyamide resin. U.S. Patent Nos. 4,331,786, 5,919,865, 6,368,723, 6,025,055, etc. disclose various methods for improving impact properties, but there are limitations in the areas of flexibility, chloride resistance and barrier properties.

For the purpose of improving the stability of solution and gasoline, various reinforcing methods for polyamide resins are proposed in US Pat. Nos. 4,814,379, 5,013,789, 5,814,384, and Korean Patent Nos. 0265500 and 0591449. It has problems such as characteristics, mechanical strength, molding appearance, and reduced flexibility.

Accordingly, the inventors of the present invention have continued researches to solve the above problems, and as a result, polyamide and polypropylene are the main components, and a reactive polyamide, a softening plasticizer, and a reaction control agent are included in a specific polyamide resin composition. The present invention has been completed by developing a resin composition suitable for automobile fuel parts because it exhibits superior flexibility and appearance characteristics and excellent resistance to gasoline containing chloride and alcohol.

Accordingly, an object of the present invention is to provide a polyamide resin composition exhibiting excellent melt strength, flexibility and appearance characteristics, and excellent stability to chlorides and gasoline resistance.

The present invention provides a polyamide resin comprising 30 to 70% by weight of polyamide, 1 to 30% by weight of polypropylene, 3 to 40% by weight of reactive compatibilizer, 1 to 30% by weight of softening plasticizer and 0.3 to 5% by weight of reaction control agent. The composition is characterized by that.

The present invention relates to a polyamide resin composition having excellent resistance to chlorides, flexibility and gasoline stability, comprising a reactive compatibilizer and a softening plasticizer component having a reactor with an amide component in a polyamide resin and a polypropylene resin-based composition. The polyamide resin exhibits excellent melt strength, flexibility and appearance characteristics compared to the conventional polyamide composition including a reactive control agent, and is excellent in chloride stability and gasoline stability, and has suitable resin properties for automobile fuel parts.

Below. The present invention is described in more detail as follows.

The present invention includes a reactive compatibilizer having a reactor with an amide component in a polyamide resin, a composition based on a polypropylene resin, a softening plasticizer component and a reactivity control agent, and has excellent melt strength, flexibility and The present invention relates to a polyamide resin composition exhibiting external appearance characteristics and excellent in chloride stability and gasoline stability.

The present invention forms an effective dispersion structure with polyamide resin and improves resistance to chlorides by using polypropylene resin and reactive compatibilizer together with polyamide resin, and uses flexibility plasticizer and reaction control agent together for flexibility and reaction. The reduction of surface appearance characteristics and the improvement of melt strength by extrusion were effectively induced. From this, polyamide resins can be imparted with stability to chlorides and gasoline resistance, as well as excellent polyamide resin compositions having superior melt strength, flexibility and appearance properties than conventional nylon resin compositions.

The polyamide resin may be a single or two or more polycondensation of a ring structure lactam or ω-amino acid having a three-membered ring or more as a monomer, diacids and diamine may be used. In addition, homopolyamide, copolyamide and mixtures thereof may be used, and such polyamide resin may be semi-crystalline and / or amorphous. In addition, 0.1 to 5 mol% of a multifunctional compound such as tremetic acid including three or more functional groups in addition to the divalent acid or diamine may be used.

More specifically, such polyamide resins include, for example, nylon 6, 7, 8, 10, 12, 66, 69, 610, 611, 612, 6T, 6/66, 6/12 and 6 / 6T. Among these, nylon 12, nylon 6, nylon 6/12 and the like are preferred. In addition, the polyamide resin is a resin including an amide group and a carboxyl group in the molecular structure, the polyamide resin may be selected one or more. That is, it can be used as a mixture of any combination and content ratio between the polyamide resins. In the above polymerization method, any polymerization method, such as anionic polymerization, bulk melt polymerization, solution polymerization, melt polymerization through salt, interfacial polymerization and reaction extrusion, is not limited to use. Polyamide copolymers polycondensed using more than one monomer may be used regardless of the content ratio of the components.

The polyamide resin obtained as described above may be used in an amount of 30 to 70% by weight based on the total weight of the polyamide resin composition. If the content is less than 30% by weight, gasoline and permeability may be lowered. And a decrease in the melt strength. More preferably, it is 40 to 60 weight%.

The polypropylene resin is a thermoplastic resin obtained by propylene alone. A specific example is polypropylene. The polypropylene resin obtained as described above may be used in an amount of 1 to 30% by weight based on the total weight of the polyamide resin composition. If the polypropylene resin is less than 1% by weight, the chloride resistance may be lowered.

The reactive compatibilizer is a resin grafted with maleic anhydride or acrylic acid having excellent reactivity with the amine end group of the polyamide resin. Specific examples include polyethylene graft maleic anhydride (PE-g-MA), polypropylene graft maleic anhydride (PP-g-MA), ethylene-propylene rubber graft maleic anhydride (EPR-g-MA), ethylene-octene rubber graft Maleic anhydride (EOR-g-MA) and ethylene-propylene-diene monomer rubber graft Maleic anhydride (EPDM-g-MA), polyethylene graft acrylic acid (PE-g-AA), ethylene-propylene rubber graft acrylic acid (EPR- g-AA), ethylene-octene rubber graft maleic anhydride (EOR-g-MA), ethylene-propylene-diene monomer rubber graft acrylic acid (EPDM-g-AA) and the like.

The reactive compatibilizer obtained as described above may be used in an amount of 3 to 40% by weight based on the total weight of the polyamide resin composition. If the amount is less than 3% by weight, the dispersion commercialization effect cannot be obtained. If the amount is more than 40% by weight, the gasoline resistance is lowered. More preferably 10 to 30% by weight.

As a softening plasticizer component, the component which improves the softness of polyamide resin is used. Specific examples thereof include one or more components selected from lactam series such as caprolactam and lauryl lactam, toluene sulfonamide derivatives, glycolates, phthalates, adipates and phosphate plasticizers. The softening plasticizer may be used 1 to 30% by weight, more preferably 5 to 20% by weight based on the total weight of the polyamide resin composition.

The reaction control agent component is used for the purpose of effectively inducing the control of the melt strength and the deterioration of the surface appearance by the reaction of the polyamide, the reactive compatibilizer and the softening plasticizer. Compounds in the form of polymers or oligomers having two or more functional groups in the molecular structure that can react with the polyamide or softening plasticizer component can be used. In particular, carboxylic acid, carbodiimide and maleic anhydride functional groups are preferred, but are not particularly limited because the variety of functional groups satisfying the above characteristics is very diverse. Representative examples thereof include at least one compound selected from the group consisting of styrene maleic hydride resins, phenol noblock epoxy, cresol noblock epoxy, polyphenylene carbodiimide and carbodiimide-based compounds such as polyphenylmethane carbodiimide have.

The reaction control agent may be used at 0.3 to 5% by weight based on the total weight of the polyamide resin composition. If the content is less than 0.3% by weight, it is difficult to control sufficient appearance and control the melt strength. When the content is more than 5% by weight, there is a drastic decrease in workability due to excessive reaction. Therefore, it is necessary to add an appropriate amount of the reaction control agent, and when used properly in combination with the reactive compatibilizer and the softening plasticizer can obtain the optimum physical properties. More preferably 0.5 to 4% by weight is used.

In addition, ones such as metal stabilizers, light stabilizers, heat stabilizers, ultraviolet stabilizers, lubricants, mold release agents, pigments, dyes, flame retardants, reinforcing agents, antistatic agents, conductive additives, EMI shielding agents, nucleating agents, antibacterial agents, deodorants and lubricants as needed Or further additives may be added within a range that does not affect the physical properties, appearance, formability.

In addition, a molded part comprising the polyamide resin composition according to the present invention may also be included.

Hereinafter, the present invention will be described in more detail based on examples. However, the scope of the present invention is not limited by the following examples.

Example  1 to 5 and Comparative example  1 to 3: Poly Amide  Preparation of Resin Composition

After mixing at the ratio shown in Table 1 above, and mixing in a Henschel mixer for 3 minutes, pellets for the melt-kneaded resin composition were prepared using a twin screw extruder (diameter 40 mm Φ) set to 250 ℃. After drying the obtained pellets, a specimen for measuring melt strength and physical properties was prepared through injection molding.

TABLE 1

Note) Polyamide 1: Polyamide 12 (PA12)

    Polyamide 2: Polyamide 6 (PA6)

    Polypropylene (PP, LG Chemicals)

    Ethylene-propylene copolymers (EP, LG Chemical)

    Reactive Compatibilizer 1: Ethylene-octene graft maleic anhydride (EOR-g-MA)

    Reactive Compatibilizer 2: Propylene Graft Maleic Anhydride (PP-g-MA)

    Softening Plasticizer 1: Sulfonamide

    Softening Plasticizer 2: Caprolactam (Korea Caprolactam Product)

    Reaction Control Agent: Styrene Maleic Anhydride (SMA)

Test Example

The melt strength and tensile elongation were tested in the following manner.

Melt strength and tensile elongation of Examples 1 to 5 and Comparative Examples 1 to 3 were measured using a Rheotens melt strength tester manufactured by Gottfert by attaching a capillary die to a single screw extruder manufactured by Haake. The device mounts the extrudate between two rolls that rotate the extrudate in different directions and gives a constant acceleration to rotate the rolls to produce the melt strength and tensile elongation values as the force and rotational speed at the time the extrudate breaks. Available and measurements were performed at an extrusion temperature of 250 ° C.

The volume change of the Examples 1 to 5 and Comparative Examples 1 to 3 is filled with a certain amount of gasoline containing 20 wt% alcohol in the metal container, 6.4mm x 12.7mm x with the resins of Examples 1-5 and Comparative Examples 1-3. 127 mm Bar specimens were prepared by an injection molding machine, the aluminum container was sealed with the Bar specimens, and placed in a 60 ° C. dryer for 10 days to measure volume change.

Chloride resistance was prepared by injecting ASTM specimens for tensile strength evaluation, immersing the specimens in 25 wt% ZnCl ₂ solution (100 ° C.) for 500 hours, and leaving the specimens in a constant temperature and humidity room for 24 hours. Tensile strength retention and appearance cracks were observed before and after the deposition test.

Table 2 shows the measurement results of tensile strength, flexural strength, melt strength, gasoline stability, chloride resistance, and impact strength measured by the above-described experimental method.

TABLE 2

Note) Tensile Strength and Tensile Elongation: ASTM D638

     Flexural Modulus and Flexural Strength: ASTM D790

     Izod impact strength (room and low temperature): ASTM D256

     Appearance (surface projections): Observation of the uniformity of the extruded surface

    Volume change observed after gasoline deposition (with 20wt% alcohol): 1 (fine change), 2 (medium change), 3 (high change)

     Observation of appearance deformation and crack before and after chloride resistance test

As shown in Table 2, the examples including the polyamide resin and the polypropylene, the reactive compatibilizer, the softening plasticizer, and the reaction controlling agent include Comparative Example 1, which does not include the reaction controlling agent, and the reaction controlling agent. Compared with Comparative Example 2, which does not contain a compatibilizer, and Comparative Example 3 using ethylene-propylene copolymer resin instead of polypropylene resin, it shows excellent melt strength, flexibility and appearance characteristics, and has excellent stability against chloride and gasoline stability. It can be seen. From the above results, it can be seen that the selection of polypropylene, reactive compatibilizer, softening plasticizer and reaction control agent has a great effect on chloride resistance, gasoline stability, physical properties and processing appearance, and the polyamide resin composition according to the present invention has good processability. , Flexibility and appearance uniformity.

Claims (7)

30 to 70% by weight polyamide resin, 1 to 30% by weight polypropylene resin, 3 to 40% by weight reactive compatibilizer, 1 to 30% by weight softening plasticizer and 0.3 to 5% by weight reaction control agent Polyamide resin composition with excellent chloride and gasoline stability. The composition of claim 1, wherein the polyamide resin is selected from the group consisting of nylon 12, nylon 6, nylon 6/12, and a resin containing an amide group and a carboxyl group in a molecular structure. The method of claim 1, wherein the reactive compatibilizer is polyethylene graft maleic anhydride (PE-g-MA), polypropylene graft maleic anhydride (PP-g-MA), ethylene-propylene rubber graft maleic anhydride (EPR-g -MA), ethylene-octene rubber graft maleic anhydride (EOR-g-MA) and ethylene-propylene-diene monomer rubber graft maleic anhydride (EPDM-g-MA), polyethylene graft acrylic acid (PE-g-AA), 1 from the group consisting of ethylene-propylene rubber graft acrylic acid (EPR-g-AA), ethylene-octene rubber graft maleic anhydride (EOR-g-MA) and ethylene-propylene-diene monomer rubber graft acrylic acid (EPDM-g-AA) A composition characterized in that at least one species is selected. The composition of claim 1, wherein the softening plasticizer is selected from the group consisting of caprolactam, lauryl lactam, toluene sulfonamide derivatives, glycolates, phthalates, adipates and phosphates. The method of claim 1, wherein the reaction control agent is selected from the group consisting of styrene maleic anhydride resin, phenol noblock epoxy, cresol noblock epoxy, polyphenylene carbodiimide and polyphenylmethane carbodiimide compound Characterized in that the composition. The group of claim 1, consisting of metal stabilizers, light stabilizers, thermal stabilizers, ultraviolet stabilizers, lubricants, mold release agents, pigments, dyes, flame retardants, reinforcing agents, antistatic agents, conductive additives, EMI shielding agents, nucleating agents, antibacterial agents, deodorants and lubricants The composition further comprises an additive selected from at least one member. A molded part comprising the composition of any one of claims 1 to 6.