JP2019099782A - Polypropylene resin composition - Google Patents

Abstract

To provide a polypropylene resin composition capable of manufacturing a molded article excellent in scratch resistance (initial and after heat resistant), rigidity and impact resistance.SOLUTION: A polypropylene resin composition contains Component (A), Component (B), and Component (C), and has content of the Component (A) is 70 to 90 pts.mass, content of the Component (B) is 10 to 30 pts.mass and content of the Component (C) is 1 to 5 pts.mass based on 100 pts.mass of total of the content of the Component (A) and the content of the Component (B). (A) polypropylene: (B) talc having average particle diameter of 1 μm to 8 μm; (C) polyethylene glycol having molecular weight at a refractive index intensity maximum point in chromatogram obtained by using differential refractive index in a gel permeation chromatography of 4,001 to 14,000, and S/Sof 1.4 to 2.0, wherein peak area from an elution initiation point to elution time corresponding to the refractive index intensity maximum point is S, and peak area from the elution time corresponding to the refractive index intensity maximum point to an elution end point is S.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polypropylene resin composition capable of producing a molded article excellent in scratch resistance (initial and after heat resistance), stiffness and impact resistance.

  Conventionally, polyvinyl chloride has mainly been used as a material of interior parts such as an instrument panel and a door trim of a car. However, from the point of being excellent in moldability, lightness, recyclability, economical efficiency, etc., substitution to polypropylene composite material blended with talc is in progress. However, this polypropylene composite is prone to material destruction starting from talc, and has the disadvantage of being inferior in scratch resistance and impact resistance as compared to polyvinyl chloride.

  A scratch attached to a polypropylene composite compounded with talc has a problem that light scattering occurs and the surface becomes noticeable white because minute irregularities are caused on the surface of the scratch due to material destruction starting from talc. Various methods have been proposed to solve such problems. For example, Patent Document 1 proposes a composition in which scratch resistance is improved by adding a fatty acid amide to a polypropylene-based composite material containing talc.

JP, 2010-43252, A

  However, since fatty acid amide is relatively compatible with polyropyrene, it does not easily migrate to the surface of the molded article, and the effect of improving the scratch resistance is insufficient. In addition, since fatty acid amide is highly volatile, there is a problem that scratch resistance is impaired when it is heated.

  An object of the present invention is to provide a polypropylene resin composition capable of producing a molded article excellent in scratch resistance (initial and after heat resistance), rigidity and impact resistance.

The polypropylene resin composition according to the present invention contains the following component (A), component (B) and component (C), and the total of the content of component (A) and the content of component (B) is 100 mass The content of component (A) is 70 to 90 parts by mass, the content of component (B) is 10 to 30 parts by mass, and the content of component (C) is 1 to 5 parts by mass It is characterized by being.

(A) Polypropylene (B) Talc having an average particle size of 1 μm to 8 μm (C) Polyethylene glycol, which is obtained by using a differential refractometer in gel permeation chromatography at the maximum refractive index intensity point The peak area from the elution start point to the elution time corresponding to the refractive index maximum point is S _1, and the elution end point to the elution end point from the elution time corresponding to the refractive index intensity maximum point when the peak area up to the _{S 2, S 2} / _{S 1} is 1.4 to 2.0.

  According to the present invention, by blending specific polyethylene glycol in polypropylene compounded with talc, the lubricity of the surface of the molded article at the beginning and after heat resistance, and the interfacial strength between polypropylene and talc are improved, and scratch resistance is achieved. It is possible to provide a polypropylene resin composition capable of producing molded articles excellent in rigidity and impact resistance (initially and after heat resistance).

FIG. 1 is a model chromatogram diagram for explaining peak areas S ₁ and S ₂ defined in the present invention.

Hereinafter, the present invention will be described in detail.
<(A) Polypropylene>
As the polypropylene (A) used in the present invention, homopolypropylene obtained by polymerizing propylene alone, random polypropylene obtained by copolymerizing propylene and ethylene, and homopolypropylene are polymerized, and subsequently copolymerization of propylene and ethylene in the presence of homopolypropylene Block polypropylene. Among these, block polypropylene is particularly preferable from the viewpoint of balance between rigidity and impact resistance.

  Examples of block polypropylenes include J708UG, J830HV, J715M manufactured by Prime Polymer, PMA60Z and PMB60A manufactured by Sun Aroma, BC02N manufactured by Japan Polypropylene, BC03GS and the like.

<(B) Talc>
The talc used in the present invention has an average particle diameter measured by a laser diffraction method in the range of 1 μm to 8 μm. When the average particle size is larger than 8 μm, scratch resistance is deteriorated. If the average particle size is smaller than 1 μm, the cohesive force between the talcs is large, causing dispersion failure in polypropylene, and the scratch resistance (initial and after heat resistance), rigidity and impact resistance deteriorate.

<(C) polyethylene glycol>
The polyethylene glycol used in the present invention has a weight average molecular weight of 4,001 to 14,000 at the maximum refractive index intensity point in a chromatogram obtained using a differential refractometer in gel permeation chromatography. Furthermore, when the peak area up to the elution time corresponding to the refractive index intensity maxima from the elution starting point and S _1, the peak area up to the elution end point from the elution time corresponding to the refractive index intensity maxima was S _{2, S 2} / S ₁ is 1.4 to 2.0.

Even if S ₂ / S ₁ is 1.4 to 2.0, scratch resistance (after heat resistance) is reduced if the molecular weight of polyethylene glycol is less than 4,001. From these viewpoints, the molecular weight of polyethylene glycol is 4,001 or more, preferably 4,300 or more, more preferably 5,000 or more, and most preferably 6,000 or more. _Further, even in S 2 / _{S 1} is 1.4 to 2.0, the molecular weight is larger than 14,000, the rigidity is lowered. From such a viewpoint, the molecular weight of polyethylene glycol is 14,000 or less, and more preferably 12,000 or less.

Even if the molecular weight of polyethylene glycol is 4,001 to 14,000, when S ₂ / S ₁ is smaller than 1.4, the rigidity and the impact resistance are reduced. Therefore, S ₂ / S _{1 is set} to 1.4 or more, and more preferably set to 1.5 or more. Further, even in the molecular weight of the polyethylene glycol 4,001～14,000 _and S 2 / _{S 1} is greater than 2.0, since the scratch resistance (after heat) is _reduced, S 2 / _{S 1} Is set to 2.0 or less, and more preferably set to 1.8 or less.

This requirement is further described below.
The peak area ratio (S ₂ / S ₁ ) is defined in gel permeation chromatography (GPC) by the chromatogram obtained using a differential refractometer. The chromatogram is a graph showing the relationship between the refractive index intensity and the elution time.

  Here, FIG. 1 is a model diagram of a chromatogram obtained by gel permeation chromatography of polyethylene glycol, the horizontal axis indicates the elution time, and the vertical axis indicates the refractive index intensity obtained using the differential refractometer. .

  When a sample solution is injected into a gel permeation chromatograph and developed, elution starts from the molecule with the highest molecular weight, and the elution curve rises as the refractive index intensity increases. Thereafter, the elution curve descends after passing the point K at which the refractive index intensity becomes maximum.

  Polyethylene glycol usually has one refractive index intensity maximum point in the chromatogram in gel permeation chromatography, and often has a unimodal peak. Under the present circumstances, the peak resulting from the developing solvent etc. which were used for gel permeation chromatography, and the pseudo peak by the fluctuation of the baseline resulting from the used column and apparatus are remove | excluded. Further, when there are a plurality of refractive index intensity maximum points, the point having the largest intensity among them is taken as the refractive index intensity maximum point.

Here, the peak area from the elution start point O to the elution time C corresponding to the refractive index intensity maximum point K is taken as S ₁ . In addition, the elution time C is at the intersection of a perpendicular P drawn from the refractive index intensity maximum point K to the baseline B and the baseline B. Then, the peak area from the elution time C until dissolution end point E and S _2. Peak area S ₁ corresponds to the amount of components of relatively high molecular weight side, the peak area S ₂ corresponds to the amount of components of relatively low molecular weight side. And that S ₂ / S ₁ is 1.4 to 2.0 means that the component on the low molecular weight side is more than the component on the high molecular weight side, and the balance of this molecular weight is a polypropylene resin composition It contributes to the scratch resistance (initial and after heat), stiffness and impact resistance of products.

In the present invention, gel permeation chromatography (GPC) for determining the peak area ratio (S ₂ / S ₁ ) uses TOSOH HLC-8320 GPC as a GPC system and two TOSOH TSKgel Super Multipore HZ-M as a column. And, one TOSOH TSKgel Super H-RC is continuously attached. Then, the column temperature is set to 40 ° C., the reference substance is polystyrene, and tetrahydrofuran is used as a developing solvent. The developing solvent is flowed at a flow rate of 1 ml / min, 0.1 ml of a sample solution with a sample concentration of 0.1% by weight is injected, and it is expressed by refractive index strength and elution time using EcoSEC-Work Station GPC calculation program. Obtain a chromatogram.

(Ratio of each ingredient)
In the present invention, when the total of the content of the component (A) and the content of the component (B) is 100 parts by mass, the content of the component (A) is 70 to 90 parts by mass, and the component (B) The content of is 10 to 30 parts by mass. When the content of the component (B) exceeds 30 parts by mass, the scratch resistance (initial and after heat resistance) and impact resistance of the resin composition are lowered. Moreover, the rigidity and impact resistance of a resin composition fall that content of a component (B) is less than 10 mass parts.

  When the total of the content of (A) polypropylene and the content of (B) talc is 100 parts by mass, the content of (C) polyethylene glycol is 1 to 5 parts by mass. This improves the scratch resistance (initial and after heat resistance), rigidity and impact resistance of the polypropylene resin composition. From this viewpoint, the content of (C) polyethylene glycol is preferably 2 to 4 parts by mass.

<Other additives>
The polypropylene resin composition of the present invention is added with other additives such as a rubber, a plasticizer, a softener, an antioxidant, a processing aid, a flame retardant, an ultraviolet absorber, a coloring agent and the like within the range not to inhibit the effect. can do.

  The polypropylene resin composition of the present invention can be produced by melt-kneading (A) polypropylene, (B) talc and (C) polyethylene glycol, and the kneading temperature is preferably 180 to 260 ° C., preferably It may be performed at 200 to 240 ° C.

  For kneading of (A) polypropylene, (B) talc and (C) polyethylene glycol, a continuous extruder such as a single-screw extruder, a twin-screw extruder, or a twin-rotor extruder can be used. . The obtained polypropylene resin composition can be molded into a predetermined shape by a known molding method such as an extrusion molding method, an injection molding method, a blow molding method, or a compression molding method.

  The polypropylene resin composition of the present invention is excellent in scratch resistance (initially and after heat resistance), rigidity and impact resistance. Therefore, it can be suitably used as a material of interior parts such as instrument panels and door trims of automobiles.

Hereinafter, specific examples of the present invention will be described.
<Polypropylene resin composition>
Each component was dry-blended with the composition shown in Table 1 and Table 2, and a polypropylene resin composition was obtained by kneading and granulating with a twin-screw extruder at a set temperature of 230 ° C. The obtained polypropylene resin composition was injection molded with an injection molding machine at a cylinder temperature of 230 ° C. and a mold temperature of 30 ° C., and scratch resistance (initial and after heat resistance), rigidity and impact resistance were evaluated.

The evaluation method of each performance is as follows.
<Scratch resistance (initial)>
Test pieces (80 mm × 55 mm × t2 mm) were scratched in a grid pattern of 20 squares each at a distance of 2 mm under a load of 5 N, a pin shape of 1 mmφ and a scratching speed of 1,000 mm / min Attached. Subsequently, using SQ-2000 manufactured by Nippon Denshoku Kogyo, the lightness index L before and after the scratch of the test piece is measured under the conditions of the light source C, the visual field 10 °, and the measurement surface φ30 mm, and the difference (ΔL) is calculated. did. This L is a value of L ^* a ^* b ^* color space specified in JIS Z 8781-4.

<Scratch resistance (after heat resistance)>
After leaving the test piece (80 mm × 55 mm × t2 mm) in a gear oven set at 80 ° C. for 168 hours, using a scratch tester 430P made by ERICHSEN, a load of 5 N, a pin shape of 1 mmφ, and a scratching speed of 1,000 mm / min Then, 20 horizontal and 20 vertical lines were scratched at intervals of 2 mm. Subsequently, using SQ-2000 manufactured by Nippon Denshoku Kogyo, the lightness index L before and after the scratch of the test piece is measured under the conditions of the light source C, the visual field 10 °, and the measurement surface φ30 mm, and the difference (ΔL) is calculated. did. This L is a value of L ^* a ^* b ^* color space specified in JIS Z 8781-4.

<Stiffness>
The flexural modulus was measured at 23 ° C. at a bending speed of 2 mm / min in accordance with JIS K 7171.

<Impact resistance>
The Izod impact strength of the notched test piece was measured at 23 ° C. in accordance with JIS K 7110.

  As is clear from the results in Table 1, Examples 1 to 12 were all excellent in scratch resistance (initial and after heat resistance), rigidity, and impact resistance.

On the other hand, in Comparative Examples 1 to 10, these performance balances were insufficient.
Specifically, Comparative Example 1 was inferior in rigidity and impact resistance because it did not contain talc.
Comparative Example 2 was inferior in scratch resistance (initial) and impact resistance since talc was excessive.
In Comparative Example 3, since the average particle diameter of talc was too small, the abrasion resistance (initial), the rigidity, and the impact resistance were inferior.
Comparative Example 4 was inferior in scratch resistance (initial) because the average particle size of talc was too large.

The comparative example 5 was inferior to scratch resistance (after heat resistance), since the molecular weight of polyethyleneglycol was too small.
Comparative Example 6 was inferior in rigidity because the molecular weight of polyethylene glycol was too large.
Comparative Example 7 was inferior in rigidity and impact resistance because S ₂ / S ₁ in gel permeation chromatography of polyethylene glycol was too small.
Comparative Example 8 was inferior in scratch resistance (after heat resistance) because S ₂ / S ₁ in gel permeation chromatography of polyethylene glycol was excessive.
Comparative Example 9 was inferior in scratch resistance (initial and after heat resistance) and impact resistance because the blending amount of polyethylene glycol was too small.
Comparative Example 10 was inferior in rigidity and impact resistance because the blending amount of polyethylene glycol was excessive.

Hereafter, the suitable compounding example of the polypropylene resin composition of this invention is demonstrated. The polypropylenes of Formulation Examples 1 to 3 used were J708UG manufactured by Prime Polymer, talc used talc having an average particle diameter of 3 μm, and polyethylene glycol used polyethylene glycol having a molecular weight of 9,500 and S ₂ / S ₁ of 1.8.

Formulation Example 1
Polypropylene 80 parts by mass Talc 20 parts by mass Polyethylene glycol 3 parts by mass Ethylene-propylene rubber 10 parts by mass Pentaerythritol tetrakis [3- (3,5- (5,5-)
Di-tert-butyl-4-hydroxyphenyl)
Propionate] 0.1 parts by mass of tris (2,4-di-tert-butylphenyl)
Phosphite 0.1 parts by mass

Formulation Example 2
Polypropylene 70 parts by mass Talc 30 parts by mass Polyethylene glycol 3 parts by mass 2- (5-chloro-2H-benzotriazole-
2-yl) -6-tert-butyl-4-
Methylphenol 0.1 parts by mass tetrakis (2,2,6,6-tetramethyl-4-
Piperidyl) futan-1,2,3,4-tetracarboxylate 0.1 parts by mass

Formulation Example 3
Polypropylene 80 parts by mass Talc 20 parts by mass Polyethylene glycol 3 parts by mass Carbon black 1 part by mass 2,6-di-tert-butyl-p-cresol 0.1 parts by mass Calcium stearate 0.1 parts by mass Bis (2,2,2 6,6-Tetramethyl-4-
Piperidyl) Sebacate 0.2 parts by mass

  The polypropylene resin compositions obtained in Formulation Examples 1 to 3 were all excellent in scratch resistance (initial and after heat resistance), rigidity and impact resistance.

Claims (2)

The component (A) contains the following component (A), component (B) and component (C), and the sum of the content of the component (A) and the content of the component (B) is 100 parts by mass; The content of A) is 70 to 90 parts by mass, the content of the component (B) is 10 to 30 parts by mass, and the content of the component (C) is 1 to 5 parts by mass. To be, polypropylene resin composition.

(A) Polypropylene

(B) talc having an average particle size of 1 μm to 8 μm

(C) Polyethylene glycol having a molecular weight of 4,001 to 14,000 at the maximum refractive index intensity in the chromatogram obtained using a differential refractometer in gel permeation chromatography, and from the elution start point Assuming that the peak area up to the elution time corresponding to the maximum refractive index intensity point is S _1, and the peak area from the elution time corresponding to the maximum refractive index intensity point to the elution end point is S ₂ , S ₂ / S ₁ is 1.4 to 2.0.
  The polypropylene resin composition according to claim 1, wherein the molecular weight at the refractive index strength maximum point is 5,000 to 14,000.

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