JPS6060154A - Polypropylene resin composition - Google Patents

Abstract

PURPOSE:The titled composition having excellent paintability and stiffness, consisting of a specified crystalline thylene-propylene block copolymer, an ethylene- propylene copolymer rubber, an ethylene-propylene-diene terpolymer rubber, and an inorganic filler. CONSTITUTION:90-60pts.wt. crystalline ethylene-propylene copolymer (A), containing 6-30wt% ethylene, and polypropylene which gives 75wt% or more insolubles in boiling n-heptane, an intrinsic viscosity of tetraline solution at 135 deg.C of 1.2-2.0, and an MFT of 8 or higher, 5-35pts.wt. ethylene-propylene copolymer rubber (B), having 20-70wt% propylene, and a Mooney viscosity at 100 deg.C of 15-100, 35pts.wt. or less entylene-propylene-diene terpolymer rubber (C), having 20-50wt% propylene, a Mooney viscosity at 100 deg.C of 20-110, and the diene being dicyclopentadiene, ethylidene-norbonene, or 1,4-hexadiene, and an inorganic filler (D) of a particle diameter of 6mu or less in an amount of 2-25pts. wt. per 100pts.wt. (A)+(B)+(C), are compounded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polypropylene resin composition that has excellent coating properties, high rigidity, high impact resistance, and high molding fluidity.

Currently, polypropylene resin is widely used because it has a low specific gravity, high rigidity, and excellent heat resistance and chemical resistance, but initially it had poor impact resistance, especially at low temperatures, so it was difficult to use at low temperatures. It was unsuitable for

For this reason, impact-resistant grades made from copolymerization of ethylene and propylene have been developed and are now on the market, but recently the required performance has become increasingly sophisticated, and in many cases the impact resistance equivalent to that of impact-resistant grades is not sufficient. It's here. For example, in fields such as automobile bumpers, bumper skirts, and trims, resins with contradictory properties such as high rigidity, high heat resistance, easy painting, and high impact resistance are required. With the increasing demand for molding fluidity, even higher molding fluidity is required.

Therefore, in order to improve the impact resistance and paintability of polypropylene resin, a method has been used in which an impact resistance modifier such as ethylene-propylene copolymer rubber is added to polypropylene resin. However, resin compositions to which such impact resistance modifiers are added have the disadvantage that although impact resistance and paintability are improved, rigidity, heat resistance, and molding fluidity are reduced.

Furthermore, in order to improve the rigidity of polypropylene resin, a method of adding an inorganic optical fiber is widely used. In this method, as the proportion of the inorganic optical fiber added increases, the rigidity and heat resistance are improved, but on the other hand, it is known that the impact resistance is significantly reduced. For example, industrial material V
o1.20. IG 7.29 (1972) shows that as the amount of talc added to polypropylene increases, the stiffness and heat distortion temperature improve, but the Izod impact strength decreases. Also plastic Vo1.1
7, p. 612.27 (1966), it is shown that the Izod impact strength similarly decreases when quartzite, calcium carbonate, talc, and asbestos are added to polypropylene. However, the inorganic photoresist materials used in these methods are extremely small (general materials, and no attention is paid to particle size, etc.).

In order to improve the rigidity and paintability and impact resistance of polypropylene resin, the present inventors have developed an inorganic optical fiber material and an ethylene-propylene copolymer rubber (hereinafter abbreviated as EPM) or ethylene-propylene-diene rubber. Various attempts have been made to simultaneously use impact-resistant modifiers such as terpolymer rubber (hereinafter abbreviated as EPDM), but the generally used inorganic optical fibers with a particle size of 7 μm to 150 μm cannot be used. Similar to the example shown above, as the amount of inorganic optical fiber added increased, the impact resistance decreased, and it was not possible to improve both rigidity and impact resistance at the same time.

As a result of intensive studies aimed at obtaining a polypropylene resin composition that has even better paintability, high rigidity, high impact resistance, and high molding fluidity, the present inventors found that a specific crystalline ethylene-propylene resin composition block copolymer, EP
Paintability,
The present invention was achieved by discovering the surprising fact that rigidity and impact resistance are significantly improved, and molding fluidity is also improved.

% by weight, the boiling n-hebutane insoluble content of the polypropylene component is 75% by weight or more, the intrinsic viscosity in the tetralin l35"C solution is 1.2 to 2.0, and the melt flow index content is 20 to 50% by weight. , having a Mooney viscosity of 20 to 110 at 100°C and being the third component diT-;/1-I
Z, 35% by weight or less of ethylene-propyrene-diene terpolymer rubber which is any of -t-tylidene norbornene, dicyclopentadiene, or 1,4-hexadiene, and (d) particle size 6 μm Made by adding 2 to 25 parts by weight of the following inorganic optical fibers, it has high rigidity, high impact resistance, high molding fluidity, and has excellent paintability (initial adhesion, hot water resistance, moisture resistance). Polypropylene resin composition≠negative=right force.

The crystalline ethylene-propylene block copolymer used in the present invention has an ethylene content of 6 to 30% by weight,
Polypropylene component boiling n-hebutane insoluble content of 75% by weight or more, Tetralin 135°C solution intrinsic viscosity 1.20
~2. ('1) and has a melt flow index of 8 or more.The above ethylene content is 6% by weight.
If it is less than 30% by weight, the paintability, especially the initial adhesion, of the resulting molded product will be reduced, and if it exceeds 30% by weight, the flexural modulus of the molded product will be small, and the boiling n of the polypropylene component mentioned above will decrease.
- If the hebutane insoluble content is less than 75% by weight, the flexural modulus of the molded product will be small, and the above tetralin 135°C
If the intrinsic viscosity of the solution is less than 1.20, the molded product
The Izot impact strength at 0'C becomes small, and when it exceeds 2.0, the melt flow index of the obtained polypropylene composition becomes small, and even when the above-mentioned melt flow index is less than 8, the obtained polypropylene composition Rigidity, impact resistance, and molding fluidity are low and undesirable.

The EPM used in the present invention has a propylene content of 20 to 70% by weight and a Mooney viscosity of 1 at 100°C.
5 to 100. If the propylene content is less than 20% by weight, the low-temperature impact resistance of the molded product will decrease,
If it exceeds 70% by weight, the flexural modulus and paintability of the resulting molded product will decrease, which is undesirable. Furthermore, when an EPM with a Mooney viscosity of less than 15 or more than 100 is added to the crystalline ethylene-propylene block copolymer, the dispersed particle size of the EPM becomes too small or too large (too large, resulting in poor physical property balance of the resulting molded product). becomes worse, which is not desirable.

In addition, EPI) M also has a propylene content of 20 to 50% by weight and a Mooney viscosity of 20 to 110 at 100°0,
Further, the diene as the third component is limited to one of ethylidene norbornene, dicyclopentadiene, and 1,4-hexadiene. Propylene content is 20
If it is less than 50% by weight or more than 50% by weight, the physical property balance of the obtained molded product will deteriorate, and if the Mooney viscosity is less than 20 or more than 110, EPD
If the dispersed particle size of M becomes too small or too large, the physical property balance of the resulting molded article will deteriorate, which is unfavorable in either case.

In the present invention, the combined addition ratio of EI)M and EPDM is usually 10 to 400 to 40 parts by weight, which is not preferred because the effect is small and the low temperature Izot strength group of the molded product is small. Moreover, if the molding flow of the resulting polypropylene composition is greater than 40 weight ID:%, the effect of improving impact resistance will be small, and the low-temperature Izot impact strength of the molded product will also be small, which is undesirable.

The inorganic photonic materials used in the present invention are powdered inorganic photonic materials, such as calcium oxide, magnesium oxide, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, magnesium carbonate, calcium silicate, magnesium silicate, sulfuric acid) j Lucium, calcium carbonate, barium sulfate, mono-monocalcium sulfate, talc, clay, glass, basic magnesium carbonate, dolomite, piltonite, etc., but especially calcium carbonate, barium sulfate, calcium silicate, talc [ Heavy duty power is preferable.

Further, in the present invention, it is essential that the particle size of the inorganic optical fiber used is 6 μm or less, and particularly preferably 5 μm or less. When an inorganic optical fiber having a particle size exceeding 6 μm is used, the impact resistance of the resulting polypropylene resin composition is reduced.

Regarding the particle size of inorganic optical fibers, there are commonly used definition methods such as directional diameter, directional area equal diameter, equal area diameter, and 5IJii diameter, which can be found in chemical industry handbooks. It is measured by various measurement methods such as The particle size in the present invention is an equal area diameter determined by a light transmission method, and measurement is performed using, for example, a light transmission particle size distribution machine manufactured by Seishin Enterprise Co., Ltd., model name SK (: 2000), and particle size integration. Particle size at 50% of distribution (generally D
50) can be used.

In the present invention, the addition ratio of inorganic photonic resin with a particle size of 6 μW or less is in the range of 2 to 25 parts by weight per 100 parts by weight of the resin component consisting of the crystalline ethylene-propylene prosodic copolymer, EI)M, and EPDM. be.

When the proportion of the inorganic phosphorescent resin added is less than 2 parts by weight, the effect of improving rigidity is small, which is not preferable. In addition, inorganic photoresist material is 25
If more than 1 part by weight is added, the initial adhesion of paintability will improve, but the inorganic photoresist in the resin will absorb moisture and cause blistering between the resin layer and the paint film, resulting in poor hot water resistance and moisture resistance. On the contrary, it decreases, which is not desirable.

The components used in the polypropylene composition of the present invention are mixed using a single screw extruder commonly used in the art.
It is carried out using two extrusion tools such as CM and CIM.When producing this composition, antioxidant II, which is commonly used for polypropylene resin, is used as an antioxidant, ultraviolet absorber, metal deterioration inhibitor, lubricant, and electrostatic charge. Inhibitors, foaming agents, etc. can also be blended.

The polypropylene resin composition of the present invention thus obtained has excellent rigidity, impact resistance, and molding flow tJg, so it can be applied to automobile bumpers, bumper skirts, trims, motorcycle fenders, etc. injection molding method,
It can be molded by a molding method such as an extrusion molding method or a compression molding method.

Hereinafter, the present invention will be specifically explained with reference to Examples.

In the following description, the melt flow index is AST.
M D-12381tC1 flexural modulus is ASTM I)
-790, Izot impact strength is ASTM D-25
Measured according to 6.

Example 1 Ethylene content 23.2% by weight, polypropylene component insoluble in boiling n-hebutane 85.7% by weight, Tetralin 1
Crystalline ethylene-propylene block copolymer (hereinafter abbreviated as P-A) name p 65% by weight, propylene content 26% by weight, at 100°C To EP whose Mooney viscosity is 24, I (hereinafter abbreviated as ED Kuo M-A) is 25% by weight, propylene content is 28% by weight, Mooney viscosity at 100°C is 85, and E whose third component is ethylidene norbornene. PDM is abbreviated as M-A (hereinafter referred to as EPI). ) 10% by weight, talc having a particle diameter of 1.8 μm as an inorganic optical fiber was blended in the proportions shown in Table 1, mixed in a Henschel mixer, and then pelletized in an extruder. The obtained pellets were molded into test pieces using an injection molding machine, and the flexural modulus and Izod impact strength were measured. Moreover, the paintability was evaluated by the following method. A two-component acrylic-chlorinated polypropylene base coat was applied to the test piece obtained using an injection molding machine to a thickness of 10 μm, and a two-component acrylic-urethane topcoat was then applied. Thickness 25
It was coated to a thickness of μm, dried at 90° C. for 30 minutes, and then left at room temperature for 24 hours to obtain a paintability test piece.

Cut the coating film of this test piece with a cutter to cut 1mm vertically and 1mm horizontally.
Initial adhesion was evaluated by carving out 100 base marks in between and adhering Sevenrono Note tape, then rapidly peeling off the cello tape, and determining the proportion of base marks in the remaining coating film as a percentage. Further, the paintability test piece was immersed in hot water at 40° C. for 240 hours, and then hot water resistance was evaluated by observing the state of the coating film surface and peeling off the substrate.

In addition, the pellets obtained above were heated at a temperature of 30°C and a humidity of 90°C.
After leaving it for one week in an atmosphere of 1%, it was molded using an injection molding machine.
A flat plate of 60 mm x 80 mm x 2 mm thick was molded, and the surface condition of the molded product was observed. Table 1 shows the melt flow index of the obtained monopropylene resin, the measured values of the flexural modulus and Izot impact strength of the test piece, the evaluation results of paintability, and the surface condition of the molded product.

Example 2 In Example 1, instead of PP-A, the ethylene content was 17
．． Crystalline ethylene-propylene copolymer (hereinafter abbreviated as PP-B) with a melt index flow of 47, an intrinsic viscosity of 164 as a solution of tetralin at 135°C, a boiling n-hebutane insoluble content of the polypropylene component of 86.4% by weight, and a melt index flow of 47. The test was carried out in the same manner as in Example 1, except that the test sample was used, and the results are shown in Table 1.

Example 3 In addition to Example 1, the propylene content was 50% by weight instead of EPR-A. The Mooney viscosity at 100°C was tested in the same manner as in Example 1, and the results are shown in Table 1. Ta.

Comparative Examples 1-2 In Example 1, the ethylene content was 5.5% instead of PP-A.
Crystalline ethylene-propylene block copolymer (hereinafter referred to as 1) with a melt flow index of 2% by weight, a boiling n-hebutane insoluble content of the polypropylene component of 93.8% by weight, an intrinsic viscosity of a tetralin 135°C solution of 2.1, and a melt flow index of 4. (abbreviated as P-C), or ethylene content 5.0% by weight, boiling 1-heptane insoluble content of polypropylene component 94.0% by weight
The test was carried out in the same manner as in Example I, except that a crystalline ethylene-propylene block copolymer (hereinafter 1) abbreviated as PD) with a tetralin 135°C solution having an intrinsic viscosity of 1.9 and a melt flow index of 8 was used. The results obtained are shown in Table 1 (
-ta.

Examples 4 to 9 Crystalline ethylene with ethylene content of 11.2% by weight, boiling of polypropylene component - hebutane insoluble content of 88.0% by weight, intrinsic viscosity of tetralin 135°C solution of 1.5, melt flow index of 22 - Talc with a particle size of 1.8/um, barium sulfate with a particle size of 1.2 μm, calcium carbonate with a particle size of 1.9 ttm, and calcium silicate with a particle size of 1.0 μm are listed as inorganic photoresist materials. 2
Table 2 shows the results of the test in the same manner as in Example 1.

Comparative Example 3 The test was carried out in the same manner as in Example 4 except that inorganic phosphorous was not added, and the results obtained are shown in Table 2VC.

Comparative Examples 4-5 Tests were conducted in the same manner as in Example 4, except that the amount of talc with a particle size of 1.8 μm was changed to 13,000 parts by weight. The results are shown in Table 2.

Comparative Example 6 Tests were conducted in the same manner as in Example 4, except that talc with a particle size of 7.2 μm was blended in the ratio shown in Table 2 instead of talc with a particle size of 1°8 μm. The results are shown in Table 2. Indicated.

Example 10 and Comparative Examples 7 to 11 I as a crystalline ethylene-propylene block copolymer
) r"l, the above-mentioned EPM-A, EPDM as EPM
The test was conducted in the same manner as in Example 4, except that the above EPI) M-A and calcium carbonate with a particle size of 1°9 μm were blended in the proportions shown in Table 3. The results are shown in Table 3. .

Claims (1)

[Claims] ■, The combination of the following (a), (b), and (C) 100
Based on the weight part, (,11) ethylene content 6 to 30% by weight, polypropylene component insoluble in heptane 75% by weight
Above, the intrinsic viscosity of the tetralin solution (135°C) is 1.2
~2.0, melt flow index of 8 or higher, 90 to 60 parts by weight of crystalline ethylene-propylene block copolymer, (b) propylene content of 20 to 70% by weight, 100
5 to 35 parts by weight of ethylene-propylene copolymer rubber having a Mooney viscosity of 15 to 100 at 100°C, (C') having a propylene content of 20 to 50% by weight and a Mooney viscosity of 20 to 110 at 100°C. And the diene which is the third component is ethylidene norbornene, dicyclopentanediene, 1
, 4-hexadiene, and (d) 2 to 25 parts by weight of an inorganic optical fiber having a particle size of 6 μm or less. A polypropylene resin composition characterized by: