KR101352760B1 - Polypropylene resin composition with low density, excellent scratch resistance and surface appearance - Google Patents

Abstract

The present invention relates to a polypropylene resin composition having excellent low specific gravity, scratch resistance and appearance characteristics. The present invention relates to a high crystalline polypropylene resin (HIPP), rubber component and polypropylene having an isotactic peptide content of 96% or more by C-NMR method. Including nano masterbatch, the rigidity required for basic parts is secured while being low in weight, and the weight can be reduced, and other scratch and surface appearance characteristics are excellent. It is about.

Description

POLYPROPYLENE RESIN COMPOSITION WITH LOW DENSITY, EXCELLENT SCRATCH RESISTANCE AND SURFACE APPEARANCE with excellent specific gravity, scratch resistance and appearance characteristics

The present invention relates to a polypropylene resin composition having excellent low specific gravity, scratch resistance, and appearance characteristics, and more specifically, it can save weight while securing rigidity required for basic components and lower weight, and other scratch and surface appearance characteristics The present invention relates to a polypropylene resin composition that is excellent and particularly easy to use for automotive interior materials.

Recently, in the automotive industry, the development of new products is accelerating with the goal of improving fuel efficiency through eco-friendly and light weight. Reflecting this, as the automotive parts gradually become thinner, the mechanical properties of the material should be better, and the quality of the surface of the product should be improved further by improving consumer quality awareness. With the rapid increase in the use of polypropylene resin composition, among which the specific gravity of the material itself is the lowest. Eventually, even in the plastics used, polypropylene having a low specific gravity is in the spotlight, and efforts are being made to further reduce the specific gravity of the polypropylene resin composition itself. In other words, while minimizing the inorganic content among the properties of molded parts, it is important to have the thermal properties required by the parts, to prevent discoloration, distortion, and minimization of the size of parts, etc. Development of high-quality polypropylene resin compositions for automotive interior parts is in the spotlight. Resin composition and exterior type for interior parts such as instrument panel, door trim, console body, filler and trim using polypropylene resin Applications and development of polypropylene resin compositions corresponding to about 50% of the total automotive plastic usage, such as bumpers and side molding, are urgently needed.

Recently, the main research item of automotive polypropylene material is the weight reduction of parts, through which it contributes a lot to the additional performance improvement of the automobile, such as the improvement of fuel efficiency. The composition of the polypropylene resin composition used as a standard consists of about three components such as polypropylene and an inorganic filler to supplement the rigidity and an elastomer to improve the impact characteristics. By adjusting the content or matching the components to match the properties to obtain an optimized composition.

The demand for plastic materials used as components in the automotive field is increasing continuously as the weight reduction and high performance of the materials are continuously made. In particular, among various plastic materials, polypropylene is rapidly increasing in demand compared to other plastic materials due to light weight due to low specific gravity, ease of recycling, and relatively low price. In addition, a variety of resin compositions that control the content of inorganic additives and rubber components contained while having a complex product structure by balancing the rigidity and impact characteristics for each part of the vehicle, the exterior material has been applied. Therefore, as the type of polypropylene resin composition applied for interior and exterior materials increases, productivity improvement, such as part molding conditions and mold technology, has appeared as a main problem and tends to be complicated and diverse for each product. The direct background of the increase in the number of products is that one of the resin compositions can be satisfied because the flow characteristics are good and the dimensions of the parts must be secured stably and the specific gravity must be as low as possible due to the limitation of the material of polypropylene. This is because application is difficult.

An object of the present invention is to provide a low specific gravity polypropylene resin composition having a stable dimension while showing balanced physical properties of stiffness and impact characteristics, and excellent in scratch and surface appearance characteristics.

The present invention is to achieve the above object, 40 to 98% by weight of a highly crystalline polypropylene resin (HIPP) isotactic peptides by C-NMR method is 96% or more; Rubber component 1 to 30% by weight; And it provides a polypropylene resin composition comprising 1 to 30% by weight polypropylene nano masterbatch.

In addition, the high crystalline polypropylene resin may be a block copolymer having a polydispersity index (PI) of 5 or more.

In addition, the high crystalline polypropylene resin has a melt index of 1 to 80 g / 10 min, polypropylene homopolymer, propylene-ethylene copolymer, propylene 1 butene copolymer, propylene 1 hexene copolymer, and propylene 4 methyl 1 pentene copolymer It may be at least one polymer selected from the group consisting of.

In addition, the rubber component may be at least one member selected from the group consisting of an amorphous ethylene αolefin copolymer and a styrene-based thermoplastic elastomer.

In addition, the rubber component may be ethylene-octadiene or ethylene-butadiene.

In addition, the polypropylene nano masterbatch may have a nanoclay content of 30 to 50% by weight.

In addition, the polypropylene nano masterbatch may have a nanoclay content of 10 to 40% by weight and a whisker content of 5 to 20% by weight.

In addition, the resin composition may further comprise 1 to 10% by weight based on the masterbatch for the coloring.

According to the present invention, it is a polypropylene resin composition excellent in low specific gravity and scratch resistance, exhibiting balanced physical properties of stiffness and impact characteristics, ensuring stable dimensions, and excellent in scratch and surface appearance characteristics, and particularly, used for automobile interior materials. This easy polypropylene resin composition can be provided.

The present invention is based on polypropylene resin, which has a high crystallinity and controlled molecular weight distribution, has excellent moldability and rigidity, uses a rubber component to compensate impact properties, and polypropylene nano masterbatch for supplementary additional rigidity. Let resin composition using the following be a basic concept.

The present invention is 40 to 98% by weight of the highly crystalline polypropylene resin (HIPP), isotonic peptides by the C-NMR method of 96% or more, 1 to 30% by weight of the rubber component and 1 to 30% by weight of the polypropylene nano masterbatch It relates to a polypropylene resin composition comprising a.

The polypropylene resin used in the present invention is a highly crystalline polypropylene resin, preferably a polypropylene resin having a high isotactic index, and more preferably a polypropylene resin of a high crystalline block copolymer. 40-98 weight% of highly crystalline polypropylene resin (HIPP) whose isotactic peptide content by C-NMR method is 96% or more can be used with respect to the whole polypropylene resin composition. If it is less than 40% by weight, it is difficult to exert the function of the overall PP is lowered, and if it is more than 98% by weight, it is not preferable for the function display due to insufficient content of other components.

The highly crystalline polypropylene resin is preferably a block copolymer having a broad molecular weight distribution having a PI (Polydispersity Index) of 5 or more. If the PI of the polypropylene resin is 5 or more, the flow characteristics are excellent, and the appearance characteristics can be improved, and the viscosity is lowered according to the shear force, and the workability is excellent.

The high crystalline polypropylene resin has a melt index of 1 to 80 g / 10 min, a group consisting of polypropylene homopolymer, propylene-ethylene copolymer, propylene 1 butene copolymer, propylene 1 hexene copolymer and propylene 4 methyl 1 pentene copolymer One or more polymers selected from can be used.

It is preferable that the said rubber component is 1 or more types chosen from the group of an amorphous ethylene alpha olefin copolymer and a styrene-type thermoplastic elastomer, and by this, moderate flexibility can be obtained and the impact strength characteristics, such as low-temperature impact resistance, are improved. It is possible to let.

Examples of the amorphous αolefin amorphous copolymers include propylene, butene 1, pentene 1, hexane 1, octene 1, 4-methyl pentene 1, heputene 1 and the like as the α olefin component. The styrene-based thermoplastic elastomers include SEPS, SEP, SEEPS, SBS, and SIS in addition to SEBS.

Examples of the rubber component used in the present invention include ethylene-octadiene and ethylene-butadiene rubber components, and the content of the rubber component may be 1 to 30% by weight based on the total composition. If it is less than 1% by weight, the impact mitigation effect due to the rubber component is insignificant, and it is not preferable. If it exceeds 30% by weight, the ductility is strengthened, which is not preferable due to the lack of rigidity as a part.

In the present invention, the polypropylene nano masterbatch is used for more balanced flexural stiffness and impact strength, and the uniformity of nanoclays is minimized while minimizing the deterioration of impact characteristics on the stiffness and impact properties expressed in the existing resin composition. One dispersion can provide an excellent effect on ensuring dimensional stability of the entire part.

The polypropylene nano masterbatch is for the balanced physical properties of the stiffness and impact properties by effectively increasing the flexural modulus of the mechanical strength properties while minimizing the degradation of the impact properties of the polypropylene resin composition of the present invention. Nano masterbatch is prepared by mixing the polypropylene resin, nanoclay, graft monomer and peroxide, so that the nanoclay dispersion and graft of the graft monomer occur simultaneously. That is, the preparation of the nano masterbatch may be performed in various ways under various conditions depending on the type and amount of polypropylene resin, the amount of nanoclay, the type of monomer for graft, the amount of peroxide and the characteristics required for the nanocomposites to be produced. It is preferable that it is melt-kneading in the temperature range of 180-230 degreeC especially. The mixing is It can be carried out using a mixing equipment such as batch mixer (Kneader), twin screw extruder.

The graft monomer used in the production of the polypropylene nanomaster batch is used to be grafted during some mixing of the polypropylene resin for the purpose of improving the dispersibility of the nanomaterial by modifying the hydrophilicity of the polypropylene resin. Therefore, any graft monomer generally used for grafting polypropylene resin can be used without particular limitation, and maleic acid is particularly preferable.

The peroxide used in the preparation of the polypropylene nano masterbatch is used as an initiator or a catalyst of a reaction for grafting a polypropylene resin into a monomer for grafting, and a peroxide generally used for grafting of a polypropylene resin. Can be used without any special limitation.

The polypropylene nano masterbatch may be used in the nanoclay content of 30 to 50% by weight, if less than 30% by weight is not preferable because the stiffness supplement by the inorganic particles is insignificant, if it exceeds 50% by weight is not easy to manufacture Therefore, it is not preferable.

In addition, the polypropylene nano masterbatch of the present invention may contain a whisker having a high aspect ratio for maximizing dispersion and additional stiffness by using a somewhat low specific gravity nanoclay. At this time, the nanoclay content is 10 to 40% by weight and the content of the whisker is preferably 5 to 20% by weight. If the content of the nanoclay and whisker is in the above range can be used as a complementary function. It is possible to supplement the whiskers based on the nanoclays that act as the main ingredient, and it is possible to use various formulation formulations according to the required physical properties such as stiffness.

In the present invention, the use amount of the polypropylene nano masterbatch is 1 to 30% by weight based on the total composition, when less than 1% by weight is not preferable because the reinforcing effect by the masterbatch is insignificant, and when the amount exceeds 30% by weight during processing It is not preferable because the moldability is not easy or the impact property is lowered compared to the rigidity.

Colorants which may be added to the present invention in addition to the above components include inorganic pigments and organic pigments, and inorganic pigments include aluminum flakes, aluminum powder, aluminum foil, zinc powder, bronze powder, pearl mica, titanium white, Zinc oxide, zinc sulfide, chromium yellow, barium yellow, ultramarine blue, cobalt blue, cobalt green, carbon black and the like. Moreover, as an organic pigment, a watching red, a permanent red, a palladium red, a tall binary powder, benzidine elo, phthalocyanine green, etc. are mentioned. The colorant may be added as it is or in the form of a masterbatch for color mixing with polypropylene in a proper ratio in advance. When added in the form of a color masterbatch, the content thereof is preferably 1 to 10% by weight based on the total weight of the resin composition in order to obtain a coloring effect without affecting the physical properties of the resin composition.

In the composition of the present invention, various additives, reinforcing agents, for example, long-term heat stabilizers, weather stabilizers, antistatic agents, lubricants, slip agents (SLIP agents), hexanes, flame retardants, etc. It is possible.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by Examples.

[Examples 1 and 2 and Comparative Examples 1 and 4]

The polypropylene resin molded article for automotive interior according to the embodiment of the present invention will be described together with a comparative example. In this example, the test piece according to the standard test was used as a rule and manufactured by injection molding.

The components shown in Tables 5 and 6 were kneaded by kneading each component into a kneading extruder to prepare resin compositions of Examples and Comparative Examples. Then, the mixture was dried in an oven at 90 ° C. for 3 hours in consideration of the weakening of physical properties due to water absorption in the composition. The composition was injected using a Si180-III (molding force = 180 tons) injection machine manufactured by Toyo, Japan, and the injection temperature was 180/200/200/210/210 ° C in the order of nozzles from the feeding hopper, and the injection pressure was It was molded at 60 to 100 bar, and a molded article for measuring the physical properties and a test specimen for evaluating the appearance test were prepared.

Tables 1, 2, 3 and 4 show the components and properties of the materials used in the present examples and the comparative examples. Table 1 shows the high crystalline block copolymer as a base resin as a base of the resin composition, Table 2 shows the rubber component, and Table 3 shows the specifications of the inorganic filler talc used. Table 4 shows the method of preparing the polypropylene nano masterbatch and the content of each component and the main physical properties of the masterbatch itself. The resin composition blended from the combination of these components was pelletized using a coaxial twin screw extruder, which is one of the conventional methods, and then prepared into injection molded specimens to measure specific gravity and coefficient of linear expansion. After extrusion pellets, injection molding specimens were prepared after drying at 90 ° C. for 3 hours to prevent moisture mixing. The coefficient of linear expansion of the prepared samples was measured after standing at room temperature for more than 48 hours.

Sample No. PI (230 ℃) Hardness Flow index [g / 10min]
(230 ℃, 2.16Kg) PP-1 (Bi800) 4.2 85 40 PP-2 (SBU850) 5.8 89 58

* PI is a rheological property and is a measure of molecular weight distribution as a cross over point of G 'and G ".

Sample No. Flow index [g / 10min]
(190 ℃, 2.16Kg) Wheat degree [Kgf / cm ³ ] etc Rub-1 (LC670) 5.1 0.873 C2-C8 copolymer elastomer Rub-2 (610A) 4.0 0.920 LDPE

Sample No. Sample classification Size [㎛] Talc (KR8500) Talc       Average: 3 to 6

Sample No. Composition (wt%) Ash [%] PP-Nano-1
(master
batch) * PP / Nanoclay = 70/30
* Small amount of Peroxide and MA added
Peroxide: 0.27 pph / Maleic ahnhydride: 1.5 pph
* Manufactured using Twin extruder with the composition 19.5 PP-Nano-2
(master
batch) * PP / Nanoclay / Whisker = 60/30/10
* Small amount of Peroxide and MA added
Peroxide: 0.27 pph / Maleic ahnhydride: 1.5 pph
* Manufactured using Twin extruder with the composition 24.7

 Tables 5 and 6 show the results of evaluation of physical properties and appearance performance of the resin composition prepared from the above-described raw materials.

[Property evaluation method]

1) Tensile strength

It was measured at room temperature by the method of ASTM D638.

2) Flexural modulus

It was measured at room temperature by the method of ASTM D790.

3) Izod impact strength

It was measured at room temperature by the method of ASTM D256.

4) Heat Deflection Temperature (HDT)

It was measured at room temperature by the method of ASTM D648.

5) Density

It was measured at room temperature (23 ℃) by the method of ASTM D1505.

6) scratch evaluation method

After mounting the tip with a radius of 0.5mm on the 500g weight, scrape the surface of the specimen at 10 m / min and evaluate the condition based on the following criteria to determine the water supply.

Level 1: Significant damage and overall whitening.

-Level 2: Some whitening traces are visible and scratches are clear.

-Level 3: It is difficult to find the scratches, and depending on the angle of the visible surface, traces are rarely seen.

Level 4: Hard to see whitening traces to the extent that it is difficult to recognize the extent of surface damage.

-Class 5: There are no signs of surface scratches.

7) Flow mark occurrence rate

: Inject spiral specimen of about 2.5cm in width and 2cm in thickness at the same temperature and pressure to measure the total flow length, and measure the length of the flow mark (labeled at 1mm interval in the middle of 2.5mm width). Measured by the formula

                        Flow mark occurrence length

    Flow mark occurrence rate = --------------------- X 100 (%)

                           Overall flow length

As shown in [Table 5] and [Table 6], the products with high stiffness and impact characteristics, as shown in Comparative Examples 1 to 4 of the existing automotive interior materials, have a scratch resistance characteristic of less than 3 grade, which is a meaningful water supply as interior parts. It is a situation that needs to add additives having slip characteristics and maintains high level of more than 50% in terms of flow mark generation, which is the main item of appearance characteristics, and needs to be improved. However, in Examples 1 and 2 of Table 5, not only the level of grade 3 or more that is basically available without the addition of an additive for improving scratch resistance is maintained, but also the surface quality of 20% or less in the appearance of flow marks, which are external characteristics. This is the level of improvement, and in particular, the specific gravity of the specific gravity can be reduced by about 6 to 7% compared to the reference comparative example. In addition, the use of PP nanomaster batches using whiskers in addition to nanoclays enables the expression of low specific gravity products that can be reduced by 5 to 6%, and other improvements in appearance characteristics such as scratch resistance and flow mark incidence. The level is showing. In addition, the stiffness, heat deflection temperature, and impact characteristics are somewhat lower than those of the reference comparative example for the final part application.

Claims (8)

40 to 98% by weight of a highly crystalline polypropylene resin (HIPP) having an isotactic peptide content of 96% or more by C-NMR;
Rubber component 1 to 30% by weight; And
Polypropylene Nano Masterbatch 1-30 wt%
Lt; / RTI >
The high crystalline polypropylene resin is a polypropylene resin composition, characterized in that the PI (Polydispersity Index) 5 or more. delete The method of claim 1, wherein the high crystalline polypropylene resin has a melt index of 1 to 80 g / 10 min, polypropylene homopolymer, propylene-ethylene copolymer, propylene 1 butene copolymer, propylene 1 hexene copolymer, and propylene 4 methyl 1 Polypropylene resin composition, characterized in that at least one polymer selected from the group consisting of pentene copolymer. The polypropylene resin composition according to claim 1, wherein the rubber component is at least one selected from the group consisting of an amorphous ethylene αolefin copolymer and a styrene-based thermoplastic elastomer. The polypropylene resin composition according to claim 1, wherein the rubber component is ethylene-octadiene or ethylene-butadiene. delete The polypropylene resin composition of claim 1, wherein the polypropylene nano masterbatch has a nanoclay content of 10 to 40 wt% and a whisker content of 5 to 20 wt%. The polypropylene resin composition according to claim 1, further comprising 1 to 10% by weight of the masterbatch for coloring.