KR20120028537A - Polyolefin resin composition with improved scratch resistance for preventing surface damage - Google Patents

Abstract

PURPOSE: A polyolefin resin composition with improved scratch resistance, impact resistance and dimensional stability, thereby using for various fields like a door trim, an instrument panel, interiors of a console box, appliances, electric wire cables, a non-painted bumper of vehicles, etc. CONSTITUTION: A polyolefin resin composition comprises 20-74.9 parts by weight of polyolefin, 10-30 parts by weight of thermoplastic rubber, 15-30 parts by weight of inorganic filler, 0.1-10 parts by weight of a polyamide-based slip agent, and 0.1-10 parts by weight of fluorinated resin. The inorganic filler is one or more kinds selected from talc, calcium carbonate, calcium sulfate, magnesium oxide, calcium stearate, wollastonite, mica, silica, calcium silicate, clay and carbon black. The polyolefin resin is crystalline polypropylene. The fluorine resin is polytetrafluoroethylene.

Description

Polyolefin Resin Composition with Improved Scratch Resistance for Preventing Surface Damage}

The present invention relates to a resin composition having excellent scratch resistance, and more particularly, to electric coatings such as non-painted bumpers, door trims, interior materials such as instrument panels and console boxes, home appliances, wire cables, etc., which require surface damage prevention. The present invention relates to a polyolefin resin composition having excellent moldability, dimensional stability, and particularly scratch resistance, which can be applied to various fields such as electronic products.

The material used for the unpainted bumper as an exterior material of an existing vehicle, the door trim as an interior material, an instrument panel and a console box, a home appliance, and an electric cable is moved to an assembly assembly process after injection or extrusion molding, or after moving Frequent contact with the body causes damage to the surface of the product. These surface damages are a major cause of poor appearance and productivity, and fail to meet consumer's sensitivity to the finished product. Among the main synthetic resin materials currently used in the automotive and home appliance fields, polypropylene resins include polycarbonate (PC), polystyrene (PS), polymethyl methacrylate (PMMA), acrylonitrile-butadiene-styrene copolymer resin (ABS). It has a fundamental problem that scratch resistance is significantly lower than other resin materials. Therefore, it is a limiting factor for use as interior and exterior materials for automotive interior and exterior materials and electrical / electronic products.

On the other hand, in the automotive field, the development of products that can lower the cost without the paint painting process with the high-performance automobile unpainted bumper is actively underway. In the development of such materials, scratch resistance is most important among the physical properties to prevent surface damage. It takes precedence. As such, the research on the development of high-quality resins suitable for interior materials such as unpainted bumpers, door trims, instrument panels and console boxes, etc. of automobiles with scratch resistance while simplifying the production process and lowering costs has been continuously conducted. However, there are no technical advances yet to achieve the scratch resistance required for these automobiles and electrical / electronic products. Conventional techniques for improving the scratch resistance of a polyolefin resin composition include a technique of blending silicone resins and oils into a composition composed of polypropylene and an inorganic filler, and a technique of blending polyester resins with polypropylene. have. Such silicone-based resins or oil component systems have many disadvantages such as gas and stain problems in injection molding and extrudable products, and thus are subject to major claims of customers.

Therefore, there is an urgent need to develop materials having excellent scratch resistance to prevent surface damage from exterior materials such as automobile unpainted bumpers, interior materials such as door trims, instrument panels and console boxes, home appliances, and wire cables.

The present inventors have diligently studied to solve the above-mentioned problems of the prior art, and as a result, a certain amount of highly crystalline polypropylene is added to and mixed with a thermoplastic rubber, an inorganic filler, and a polyamide slip agent and a fluororesin having the lowest coefficient of friction. When the composition is prepared, the present invention has been found to be suitable for use in automotive products and electrical / electronic products requiring excellent surface resistance, particularly scratch resistance, with excellent dimensional stability and impact resistance.

Therefore, an object of the present invention is excellent in moldability, dimensional stability, in particular scratch resistance that can be applied to various fields such as exterior coating materials such as automobile-free uncoated bumpers, interior materials such as door trims, instrument panels and console boxes, home appliances, wire cables, etc. It is to provide a polyolefin resin composition.

The above and other objects of the present invention will become apparent from the following detailed description of the invention.

The polyolefin resin composition of the present invention for achieving the above object is (A) 20 to 74.8 parts by weight of polyolefin, (B) 10 to 30 parts by weight of thermoplastic rubber, (C) 15 to 30 parts by weight of inorganic filler, (D) poly 0.1 to 10 parts by weight of the amide slip agent and 0.1 to 10 parts by weight of the (E) fluororesin.

In one embodiment, the polyolefin resin is characterized in that the high crystalline polypropylene.

In one embodiment, the highly crystalline polypropylene is a homopolymer of propylene or propylene and C ₂ -C ₁₀ Copolymer with monomer, C ₂ ~ C ₉ monomer content of 0-10 mol%, melt index of 10-60 g / 10 minutes (230 ℃) and isotactic polypropylene having high stereoregularity by C-NMR method ( Isotactic Polypropylene) fraction is more than 97%.

In one embodiment, the thermoplastic rubber is ethylene-propylene rubber (EPR), ethylene-propylene-diene rubber (EPDM), ethylene-butene rubber (EBR), ethylene-octene rubber (EOR) and styrene-butadiene rubber (SBR It is characterized in that at least one member selected from the group consisting of.

In one embodiment, the inorganic filler is one or more selected from the group consisting of talc, calcium carbonate, calcium sulfate, magnesium oxide, calcium stearate, wollastonite, mica, silica, calcium silicate, clay and carbon black. It features.

In one embodiment, the fluorocarbon resin is polytetrafluoroethylene (PTFE).

In one embodiment, the average particle size of the polytetrafluoroethylene is characterized in that 2 to 20 ㎛.

The polyolefin resin composition according to the present invention is excellent in moldability, dimensional stability, and in particular, scratch resistance to prevent surface damage, such as automobile-free bumpers, door trims, interior materials such as instrument panels and console boxes, home appliances, wire cables, and the like. Applicable to the field.

1 is a graph evaluating the scratch resistance of a test piece before adding a fluororesin to the polyolefin resin compositions prepared in Examples and Comparative Examples of the present invention and according to the amount of the fluororesin added.
FIG. 2 is an actual photograph comparing the scratch resistance of the polyolefin resin composition of the example in which the fluororesin was added (5% and 10%) and the specimen of the polyolefin resin composition of the comparative example in which the fluororesin was not added.

Hereinafter, each component which comprises the polyolefin resin composition of this invention is demonstrated.

( A) polyolefin resin

The polyolefin resin composition of the present invention is characterized in that the polyolefin is used at 20 to 74.8 parts by weight based on 100 parts by weight of the resin composition as the base resin component. In addition, the present invention is characterized by using a high crystalline polypropylene (Highly Crystalline Polypropylene) that can improve the impact resistance, high hardness and scratch resistance as compared to the general polypropylene. In addition, the highly crystalline polypropylene is a homopolymer of propylene or propylene and C ₂ -C ₁₀ Copolymer with monomers, C ₂ ~ C ₉ monomer content of 0-10 mol%, melt index of 10-60 g / 10 minutes (230 ° C), isotactic polypropylene fraction with high stereoregularity by C-NMR method It is characterized by being more than 97%.

Highly crystalline polypropylene has higher crystallinity and hardness than existing commercially available isotactic polypropylene, resulting in 20 to 30% higher stiffness, excellent heat resistance and scratch resistance, and impact resistance similar to that of conventional polypropylene. There is this.

Highly crystalline polypropylene, which is currently widely used, has an isotactic index of more than 97% in terms of stereoregularity. Higher isotactic index increases the crystallinity of polypropylene, improving the mechanical properties and heat resistance of polypropylene. Highly crystalline polypropylene can be used for the overall parts of automobile interior and exterior materials and home appliances. Among them, the stiffness and heat resistance are superior to the existing polypropylene. Is being applied to.

In the embodiment of the present invention, as the polyolefin, a highly crystalline polypropylene (CB5230, Korean Emulsification Product) having an isotactic index of 98% was used.

In the polyolefin resin composition of the present invention, when polypropylene is used in an amount less than 20 parts by weight, the stiffness and heat resistance are insufficient. When the polypropylene resin is used in an amount greater than 74.8 parts by weight, scratch resistance may be lowered.

(B) thermoplastic rubber

The polyolefin resin composition of the present invention is characterized in that the thermoplastic rubber is used in an amount of 10 to 30 parts by weight based on 100 parts by weight of the resin composition as an elastomer component for impact resistance reinforcement. In the present invention, the thermoplastic rubber is ethylene-propylene rubber (EPR), ethylene-propylene-diene rubber (EPDM), ethylene-butene rubber (EBR), ethylene-octene rubber (EOR) and styrene-butadiene rubber (SBR). It is characterized by using one or more selected from the group consisting of.

Thermoplastic rubber is a rubber-elastic rubber that is not vulcanized but is a linear polymer and is also called a thermoplastic elastomer. The thermoplastic rubber is a copolymer of ethylene and an α-olefin of C ₂ to C ₉ . Examples that can be used as α-olefins are propylene, butene, pentene, hexene, propene, octene and the like. In particular, ethylene-octene rubber (EOR) may be preferably used because the long side chain octene group has the best impact strength improvement effect and can reduce the stiffness relatively lowered as much as possible. In the embodiment of the present invention, an octene copolymer (EG8842, manufactured by Dow Chemical Co., Ltd.) having a melt index of 0.5 to 6 g / 10 minutes (190 ° C. and 2.6 kgf) and a density of 0.864 to 0.886 g / c was used as the thermoplastic rubber.

In the polyolefin resin composition of the present invention, when the thermoplastic rubber is used in less than 10 parts by weight, the impact resistance is insufficient, and when used in excess of 30 parts by weight, the rigidity is insufficient.

(C) inorganic filler

The polyolefin resin composition of the present invention is characterized in that an inorganic filler is used in an amount of 15 to 30 parts by weight based on 100 parts by weight of the resin composition as a component for heat resistance and rigidity reinforcement. In the present invention, one or more selected from the group consisting of talc, calcium carbonate, calcium sulfate, magnesium oxide, calcium stearate, wollastonite, mica, silica, calcium silicate, clay and carbon black can be used as the inorganic filler. Preferably, wollastonite and talc are used.

Talc is a mineral composed of a hydrate of magnesium silicate (Mg ₃ Si ₄ O ₁₀ (OH) ₂ ) and the like and refers to an industrial product containing mineral talc and 35 to 100% of mineral talc. Talc as a pure mineral consists of SiO ₂ (63.5%), MgO (31.7%) and H ₂ O (4.8%). Mineral talc generally has a flat plate-like structure but also exists as asbestiform fibers. . Wollastonite is a white fibrous, bulky mineral belonging to the triclinic system, also known as wollastonite, and its physical properties vary depending on the iron and manganese content.

In the present invention, it is preferable to use a filler in which the rigidity and hardness of the resin composition increase with increasing content. In Examples of the present invention, talc (KCM6300, manufactured by Kotsu) having an average particle diameter of about 1 to 20 µm was used as the inorganic filler.

In the polyolefin resin composition of the present invention, when the inorganic filler is used in an amount of less than 15 parts by weight, heat resistance, rigidity and hardness are insufficient, and when it is used in excess of 30 parts by weight, the flow index is too low and the workability is lowered.

(D) Polyamide Slip

The polyolefin resin composition of the present invention is characterized in that a slip agent is used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the resin composition as an additive component for improving slip property. In the present invention, a polyamide-based resin is used as the slip agent.

Slippering agent refers to a material that helps flow by lubricating the metal surface in contact with plastic during calendering, molding and extrusion. That is, as an additive for preventing adhesion between the mold surface or the surface of the extruder and the resin and improving the slip property, the resin is kneaded with the resin to lower the melt viscosity to improve molding processability. In addition, the use of a slip agent lowers the processing temperature and shortens the processing time, thereby reducing deterioration during processing, thereby improving product quality.

The slip agent is applied to the polymer particles during kneading with the polymer, and when the temperature rises, the polymer and the slip agent melt together, so that the slip agent penetrates into the polymer. The rate of permeation is then determined by the solubility of the slip agent in the polymer.

In other words, the slip agent refers to an additive that reduces friction and heat of friction during synthetic resin processing and increases the fluidity of the polymer to facilitate the processing. In addition, it can be divided into two types according to the method of use. The first is mainly lubrication during molding process. For example, in order to prevent adhesion between the mold surface and the resin, the resin is kneaded to lower the melt viscosity of the resin. It is to improve the molding processability. Examples used herein include metal soaps, fatty acids and their derivatives, fatty acid amides, higher alcohols, paraffin waxes, and the like. Slip agents are classified into internal slip agents and external slip agents according to their functional functions. The internal slip agent has the effect of improving the release property and injection fluidity of the molded article by reducing friction between the polymer and the processing surface of the processing machine, the polymer ring, and mutually. The external slip agent has the effect of reducing friction between the polymer and the surface of the processing machine. As a general chemical structure, the non-polar group and the polar group are on both sides, and the polar group helps to maintain compatibility with the polymer, and the non-polar group lubricates the surface of the processing machine, and higher fatty acids, fatty acid amide compounds, and waxes are used. .

In the embodiment of the present invention, Polyarmoslip-E (manufactured by Akzo Nobel) was used as the polyamide slip agent.

When the polyamide-based slip agent is used in less than 0.1 part by weight in the polyolefin resin composition of the present invention, the improvement in slip properties is insufficient and the processing is not smooth.

(E) Fluorine Resin

The polyolefin resin composition of the present invention is characterized by using fluorine resin in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the resin composition as a component for preventing surface damage. In addition, the present invention is characterized by using polytetrafluoroethylene (PTFE) as the fluorine resin.

In the polyolefin resin composition of the present invention, the fluorine resin is the most characteristic component, and the lower the coefficient of friction of the fluorine resin is, the more advantageously used.

The molecular structure of the fluorocarbon resin is a polyethylene-like structure composed of C-C bonds, and a synthetic resin having a structure in which part or all of polyethylene hydrogen is replaced with fluorine atoms. It has a very safe molecular structure and can be used from low temperature to high temperature. 70% of the fluorocarbon resin is polytetrafluoroethylene (PTFE), which is a crystalline resin known under the trade name 'Teflon'. It is heat-resistant, resistant to long-term use at 260 ℃, and has chemical resistance, electrical insulation, and high frequency characteristics. It is a plastic excellent in non-tackiness, low friction coefficient and flame retardancy. The excellent properties of the fluorocarbon resin are due to the strong binding energy between fluorine and carbon (CF binding energy 110-116 Kcal / mol). PTFE, which is surrounded by fluorine all around the main chain of carbon, has the best properties. It is widely used in the field where it is distinguished from other polymers due to the addition of low friction and weather resistance. Heat resistant fluorine resins are flame retardant and have excellent heat resistance. In particular, tetrafluoroethylene (TFE) and perfluoroalkoxy (PFA) can be used at a commercial temperature of 260 ° C and a short time up to 300 ° C. Fluorinated ethylene propylene (FEP) is about 50 ° C. lower and polychlorotrifluoroethylene (PCTFE) can be used up to 120 ° C. Chemical-resistant fluororesins exhibit good resistance to all chemicals. PTFE, FEP and PFA are stable against all chemicals except fluorine gas, chlorine trifluoride and molten alkali metals and are not eroded by all acids, alkalis, oxidants and organic solvents.

In addition, the fluorine resin has good electrical insulation and high frequency characteristics. In particular, PTFE has the highest dielectric constant and dielectric loss tangent and excellent insulation over a wide frequency range. The friction and abrasion properties have the lowest coefficient of friction compared to all solids, especially self-lubricating. No sticky substance is adhered to the non-tacky fluororesin. PTFE is particularly strong in nature and easily falls off when it comes into contact with sticky materials. The average particle size is 2 to 20 μm and the smaller the particle size is, the more the surface area is evaluated to be better for the scratch resistance effect.

In this embodiment of the present invention, PTFE (TF9205, manufactured by 3M) was used as the fluororesin.

In the polyolefin resin composition of the present invention, when the fluorine resin is used in an amount less than 0.1 part by weight, scratch resistance may be insufficient, and surface damage may not be sufficiently prevented.

The present invention will be described in more detail with reference to the following Examples, which do not limit the scope of the present invention.

Example

First, the overall physical properties of the compositions prepared in the following Examples and Comparative Examples were evaluated by the following test methods.

1) Melt Index

Test Method: ASTM D-1238, Test Conditions: 230 ℃, 2.16kgf

2) Flexural modulus and flexural strength

Test Method: ASTM D-790, Specimen Size: 12.7 × 127 × 6.4mm, Test Condition: Crosshead Speed 28mm / min

3) Izod impact strength

Test Method: ASTM D-256, Specimen Specification: 63.5 × 12.7 × 3mm

4) heat deflection temperature

Test Method: ASTM D-648, Specimen Size: 12.7 × 127 × 6.4mm, Load: 4.6kgf

5) Scratch resistance evaluation:

Typical scratch resistance evaluation methods include pencil hardness test, five finger test, and sapphire ball test. Recently, the scratch resistance evaluation is based on GMW standard GMW14688 which is widely used in the automotive industry. . In accordance with this trend, in the present embodiment, scratch resistance was evaluated using the German Ericsson company 430P based on GMW14688. Specifically, using a hard metal pen r = 0.05 that satisfies the ISO 18262 standard (minimum 485 HV) as a test tip, the load is 10N and the width (2mm) at a speed of 1000 ± 50 mm / minute The color ΔL value for the X longitudinal (2 mm) scratching screen net was measured to evaluate this value as scratch resistance. Higher ΔL means a greater degree of surface whitening and a greater degree of scratching.

<Examples 1-4>

As shown in Table 1 below, polypropylene (CB5230, manufactured by Daehan Chemical Co., Ltd.) as the component (A), octene copolymer (EG8842, manufactured by Dow Chemical) as the component (B), talc (KCM6300, Kotsu Corporation) as the component (C) Product), polyamide (Polyarmoslip-E, manufactured by Akzo Nobel) as component (D), and PTFE (TF9205, manufactured by 3M) as component (E) for 2 minutes in a Henschel (1,100 rpm / min) mixer. Mixed. Each mixture was extruded with an extruder at a temperature in the range of 190 to 250 ° C., and then cooled and solidified to obtain a pellet-like composition. The obtained composition was injected at a temperature range of 180 to 220 ° C. according to the melt index, and then annealed under a constant temperature and humidity condition for 48 hours to prepare a specimen. The physical properties of the specimens were measured according to the test methods described above. The results are shown in Table 1, Figures 1 and 2.

<Examples 5-10>

In the same manner as in Example 1-4, except that the contents of components (B), (C) and (D) were fixed and only the contents of components (A) and (E) were changed as described in Table 1 below. Specimens were prepared and their physical properties were measured. The results are shown in Table 1, Figures 1 and 2.

<Comparative Examples 1 to 3>

In the same manner as in Example 1-4 except for changing the contents of components (A), (B), (C) and (D) without adding component (E) as shown in Table 1 below. Specimens were prepared and their physical properties were measured. The results are shown in Table 1, Figures 1 and 2.

Item Weight (kg) Flow index
(g / 10 min) IZOD strength
(kgfcm / cm) Flexural modulus
(kgf / cm ² ) Heat deformation
Temperature (℃) Scrap
Value (△ L) A B C D E 23 ℃ -30 ℃ Example One 74.8 10 15 0.1 0.1 27.9 39.6 6.7 14,750 122 9.77 2 59 15 20 3.0 3.0 24.0 37.2 7.3 14,420 129 6.27 3 43 20 25 6.0 6.0 23.7 42.4 8.5 14,787 133 1.53 4 20 30 30 10.0 10.0 20.9 48.8 9.2 15,900 138 0.57 5 47 25 25 2.0 1.0 23.4 42.3 8.2 15,500 128 9.71 6 46 25 25 2.0 2.0 23.7 43.1 7.8 15,500 127 7.54 7 44 25 25 2.0 4.0 24.7 39.8 7.4 15,600 128 4.24 8 42 25 25 2.0 6.0 25.2 44.2 7.9 15,720 129 2.13 9 40 25 25 2.0 8.0 25.7 41.4 8.2 15,700 130 1.54 10 38 25 25 2.0 10.0 24.8 43.6 8.0 15.470 124 0.72 Comparative example One 69 10 20 1.0 - 25.8 27.5 8.4 15,800 124 7.55 2 48 20 30 2.0 - 20.6 39.2 10.1 14,300 130 8.75 3 27 30 40 3.0 - 10.4 68.4 14.8 13,200 139 9.84

As can be seen from the results of Table 1 and Figs. 1-2, in the composition of the comparative example without addition of the fluororesin, the scratch resistance decreased as the inorganic filler content increased (that is, ΔL increase). In addition, as shown in Examples, when the thermoplastic rubber and the inorganic filler were changed (Examples 1 to 4) or fixed (Examples 5 to 10), the scratch resistance was improved when the fluorine resin content was increased (that is, ΔL). Decrease). In addition, the scratch resistance of the composition of Example 1-10 containing the fluorine resin as a whole was improved compared to the composition of Comparative Examples 1-3 containing no fluorine resin (that is, ΔL reduction). From these results, it can be seen that when the fluorine resin is used in a certain amount range (1-10 parts by weight), the scratch value ΔL is reduced (that is, the scratch resistance is improved) to prevent surface damage.

Polyolefin resin composition of the present invention is excellent in moldability, dimensional stability, in particular scratch resistance to prevent surface damage can be usefully used in the automotive interior and exterior materials, electrical / electronic materials industry.

Claims (7)

(A) 20 to 74.8 parts by weight of polyolefin,
(B) 10 to 30 parts by weight of the thermoplastic rubber,
(C) 15 to 30 parts by weight of the inorganic filler,
(D) 0.1 to 10 parts by weight of a polyamide slip agent, and
(E) A polyolefin resin composition comprising 0.1 to 10 parts by weight of a fluororesin. The polyolefin resin composition according to claim 1, wherein the polyolefin resin is high crystalline polypropylene. The method of claim 2, wherein the highly crystalline polypropylene is a homopolymer of propylene or propylene and C ₂ -C ₁₀ Copolymer with monomer, C ₂ ~ C ₉ monomer content of 0-10 mol%, melt index of 10-60 g / 10 minutes (230 ℃) and isotactic polypropylene having high stereoregularity by C-NMR method ( Isotactic Polypropylene) Polyolefin resin composition, characterized in that the fraction is more than 97%. The method of claim 1, wherein the thermoplastic rubber is ethylene-propylene rubber (EPR), ethylene-propylene-diene rubber (EPDM), ethylene-butene rubber (EBR), ethylene-octene rubber (EOR) and styrene-butadiene rubber (SBR Polyolefin resin composition, characterized in that at least one member selected from the group consisting of. The inorganic filler according to claim 1, wherein the inorganic filler is at least one selected from the group consisting of talc, calcium carbonate, calcium sulfate, magnesium oxide, calcium stearate, wollastonite, mica, silica, calcium silicate, clay and carbon black. The polyolefin resin composition characterized by the above-mentioned. The polyolefin resin composition according to claim 1, wherein the fluorocarbon resin is polytetrafluoroethylene (PTFE). The polyolefin resin composition according to claim 6, wherein the polytetrafluoroethylene has an average particle size of 2 to 20 µm.

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