JPH11222544A - Automotive molded resin article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automotive molded resin article of which the rise in a welded part is low and which is excellent in impact strength, stiffness, and heat resistance and is prepd. from a reinforced polypropylene resin compsn. SOLUTION: This molded article is prepd. from a glass-fiber-reinforced polypropylene resin compsn. which comprises 65 wt.% or higher polypropylene resin component and 35 wt.% or lower glass fibers and of which the melt flow rate M (g/10 min) of the resin component and the content (G wt.%) of glass fibers satisfy the relation: M<1,000/G.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molded article for automobiles, which is formed from a reinforced polypropylene resin composition and has a small weld portion.

[0002]

2. Description of the Related Art A glass fiber reinforced polypropylene resin composition (hereinafter also referred to as reinforced PPG) generally has mechanical strength,
Because of its excellent rigidity and heat resistance and low cost, it is widely used in industrial products such as automobile parts and electric appliance parts. Among these, automotive parts include engine peripheral parts such as battery trays, instrument panel cores, timing belt covers, fan shrouds, etc. Recently, exterior parts for fenders, rocker panels, wheel covers, etc. Application to parts is also being actively studied. However, reinforced PPG is used for these exterior parts.
The biggest problem when using is that the appearance quality of the resin molded product surface is inferior because it contains glass fiber.

In order to improve the surface appearance,
A method of adding an inorganic substance such as barium sulfate, calcium carbonate, and talc (Japanese Patent Publication No. 1-38565), optimization of the diameter of the glass fiber and the surface treatment agent for the glass fiber (Japanese Patent Publication No. Hei 4-4).
-12297), addition of fibrous calcium silicate (Japanese Patent Publication No. 63-67498), addition of ethylene-α-olefin rubber (Japanese Patent Publication No. 63-67499), glass fiber diameter, glass fiber sizing agent And optimization of pigment components (Japanese Patent Publication Nos. 64-6658 and 64-76)
18, No. 64-9340) and the like. These conventional methods are all based on prevention of floating of glass fiber on the surface of the resin molded product, improvement of surface gloss, prevention of silver streak (silver line by glass fiber), etc. Has an effect.

[0004]

However, even when the conventional reinforced polypropylene resin composition is used, there is a problem with the rise of the welded portion of the resin molded product. That is, the resin molded article is generally manufactured by injection molding in many cases. At that time, as shown in FIG.
There are cases where a plurality of gates 91 are provided in a cavity in a mold and molten resin is poured. Also, (B),
As shown in (C), as the product shape of the resin molded product 9,
In some cases, it has an opening 92 and a boss 95. In such a case, the flow of the resin in the cavity becomes plural, and a weld portion 93 is generated in the resin molded article 9 at a portion where the resin flow finally meets. What is important here is that the weld portion 93 forms a bulge 8 as shown in FIG.

The bulge 8 is formed particularly high when a reinforced polypropylene resin composition containing glass fibers is used, and the surface appearance of the resin molded article 9 is impaired because of the height. The swell height L reaches 40 to 100 μm when a conventional reinforced polypropylene resin composition is used.
On the other hand, from the viewpoint of surface appearance, the swell height is 35μ.
m or less. Further, it is preferably 30 μm or less. In addition, the code | symbol 82 of FIG. 6 shows a glass fiber.

In order to reduce the swelling height, a method of increasing the kneading degree and shortening the glass fiber length as much as possible in the PPG material manufacturing process (generally, the average length is 300 μm or less), A method for reducing the amount of glass fiber added is known. However, these methods have a problem that the impact strength, rigidity, and heat resistance are simultaneously reduced as the height of the weld rises. In view of the conventional problems, the present invention provides an automotive resin molded article molded from a reinforced polypropylene resin composition which has a small height of a weld portion and exhibits excellent impact strength, rigidity and heat resistance. It is something to offer.

[0007]

The present invention comprises a polypropylene resin component and glass fiber, wherein the amount of the polypropylene resin component is 65% by weight or more, and the glass fiber amount G is 35% by weight or less; In addition, the melt flow rate M (g / 10 min) of the polypropylene resin component and the glass fiber amount G (% by weight) are formed from a glass fiber reinforced polypropylene resin composition satisfying the relationship of M <1000 / G. And a resin molded article for automobiles.

In the present invention, as the polypropylene resin, a crystalline polypropylene resin, a crystalline ethylene-propylene copolymer, an unsaturated organic acid such as an acid anhydride such as acrylic acid, maleic acid, itaconic acid, and maleic anhydride; Crystalline propylene polymers modified with their derivatives and mixtures thereof are mentioned. Among them, particularly preferred is a combination of a crystalline ethylene / propylene block copolymer and a modified crystalline propylene polymer. Crystalline ethylene / propylene block copolymers have impact properties,
Ethylene component is 3-12w from the balance of rigidity and strength
It is preferable that t% is contained. It is particularly preferable that the modified crystalline propylene polymer is added with maleic anhydride in an amount of 0.1 to 2% by weight, and the addition amount is preferably 2 to 20% by weight in the total amount of PPG. As a result, mechanical properties such as impact properties, rigidity, and strength are further improved.

The melt flow rate of the polypropylene resin is preferably 1 to 100 (g / 10 minutes). If it is less than 1 (g / 10 min), the fluidity is poor, and there is a problem in moldability. On the other hand, if it exceeds 100 (g / 10 min), the impact strength may be reduced.

As the above glass fiber, a glass fiber alone can be used. The glass fiber is a single chopped strand glass fiber. Further, it is preferable that this is surface-treated with aminosilane, epoxysilane, vinylsilane or the like. It is preferable to use a glass fiber having a diameter of 3 to 20 μm. Further, the length of the glass fiber is preferably 1 to 10 mm. If it is less than 1 mm, the impact strength and bending elasticity of the resin molded product are small, while if it exceeds 10 mm, dispersion in the resin becomes poor.

The glass fiber content G is 35% or less (meaning a weight ratio; the same applies hereinafter), preferably 5 to 3%.
Must be 5%. If it is less than 5%, the reinforcing effect by the glass fiber is insufficient, and the impact strength is particularly low and it is not practical. On the other hand, if it exceeds 35%, even if the polypropylene resin is optimized, the appearance quality (especially weld swelling) is not improved. Further, between the melt flow rate M (g / 10 minutes) of the polypropylene resin and the glass fiber amount G, M
It must have a relationship of <1000 / G (see FIG. 1). If this relationship is not satisfied, the swelling height of the weld portion increases.

Various methods can be used to produce the resin molded product of the present invention. The above components are premixed by a Henschel mixer, ribbon blender, or the like, and then mixed with a single-screw extruder, a twin-screw extruder, a kneader, or the like. It is also possible to supply the mixture to a kneading machine to perform melt-kneading, granulation, and molding, or to supply only glass fibers on the way from the vent of the extruder. Further, the composition of the present invention may contain various additives such as a heat stabilizer, a light stabilizer, an ultraviolet absorber, an antistatic agent, a lubricant, a flame retardant, and a colorant, if necessary.

For fine adjustment of physical properties, cost, etc., the polypropylene resin component preferably contains an olefin or styrene elastomer. Specifically, ethylene-propylene copolymer rubber,
Ethylene rubber such as ethylene / propylene-diene copolymer rubber, ethylene / butene / 1 copolymer rubber, styrene rubber such as styrene / butadiene / styrene copolymer rubber, styrene / ethylene / butylene / styrene copolymer, etc. It is preferred that this is an elastomer. Further, the glass fiber reinforced polypropylene resin composition may contain various fillers such as talc, calcium carbonate, mica, barium sulfate, whisker, and clay.

Further, as the glass fiber, a resin-coated glass fiber can be used. The resin-coated glass fiber is a glass fiber coated in advance with a polypropylene resin, and is equivalent to a glass fiber reinforced polypropylene resin. This contains glass fibers having an average length of 1 mm or more. This resin-coated glass fiber is usually previously formed into a cylindrical pellet. This resin-coated glass fiber is usually obtained by impregnating and coating the inside and the outside of a long glass fiber bundle with a polypropylene resin, curing and then cutting the pellet into a length of 1 mm or more. Therefore, the glass fiber has the same length as the pellet and a length of 1 mm or more.

The resin-coated glass fiber has a length of 1 mm.
However, the upper limit is preferably 20 mm. If it exceeds 20 mm, the swelling height of the weld may increase. If it is less than 1 mm, impact strength and bending elasticity may decrease. Further, the diameter of the glass fiber in the resin-coated glass fiber is preferably 10 to 25 μm.
The amount of glass fiber in the resin-coated glass fiber is not particularly limited, but may be 20 to 80% by weight.
In addition, the content of the glass fiber is as high as possible from the viewpoint of economy, and it is preferable to be 40% by weight or more.

When the glass fiber alone and the resin-coated glass fiber are mixed with the polypropylene resin as the glass fiber, when these are melted and kneaded using an extrusion kneader or the like, the glass fiber alone is mixed at the raw material stage. Irrespective of the fiber length, the fiber is considerably damaged by an extrusion kneader or the like, and the average fiber length becomes 400 to 500 μm. On the other hand, the glass fiber length in the resin-coated glass fiber is 1 mm or more and is coated in advance with the resin, so that the glass fiber is less likely to be damaged than the glass fiber alone. Therefore, even after the above-mentioned kneading, the average fiber length is as long as 700 to 800 μm.

[0017] Therefore, in the obtained resin molded product, a short glass fiber and a long glass fiber are mixed as a result, and the short glass fiber has the appearance quality and the long glass fiber has the mechanical properties. It is expected to be. The average glass fiber length when the glass fiber alone and the polypropylene resin are melt-kneaded is about 600 μm, and the combined use of the resin-coated glass fiber slightly promotes the breakage of the glass fiber alone.

[0018]

In the present invention, the amount of the polypropylene resin is 65% or more, preferably 65 to 95%, the glass fiber content G is 35% or less, preferably 5 to 35%, and the melt flow rate of the polypropylene resin. The most significant feature is that when the relationship between M and the total amount G of glass fibers satisfies M <1000 / G, the rise height of the weld portion is reduced.

Further, when the physical properties of the material obtained by the prior art and the material obtained by the present invention are compared, the rise height of the weld portion is equal (that is, the appearance quality is equal).
A synergistic effect of improving the Izod impact strength, flexural modulus, and thermal deformation temperature is obtained. In other words, the amount of glass fiber to be added can be reduced under the same physical property conditions, and the appearance quality can be improved. As described above, according to the present invention, there is provided a resin molded article for automobiles formed of a reinforced polypropylene resin composition, which has a low bulging height of a weld portion and exhibits excellent impact strength, rigidity and heat resistance. be able to.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The resin molded article for automobiles of the present invention is
It comprises a polypropylene resin component and glass fiber, the amount of the polypropylene resin component is 65% or more, the glass fiber amount G is 35% or less, and the melt flow rate M (g) of the polypropylene resin component. /
10 minutes) and the glass fiber amount G (% by weight) is M <1.
It is formed of a glass fiber reinforced polypropylene resin composition satisfying the relationship of 000 / G. The glass fiber reinforced polypropylene resin composition comprises (A) a polypropylene resin, (B) a resin-coated glass fiber having a length of 1 mm or more previously coated with a polypropylene resin, and (C) a glass fiber. And kneading so that the total amount of the polypropylene resin in the component (B) is 65% by weight or more and the total amount G of the glass fibers in the components (B) and (C) is 35% or less. Is obtained by

That is, the components A to C are mixed in various ratios (weight ratio), and are melt-kneaded using a 30 mm twin screw extruder.
Granulation was performed, and then a resin molded product was injection-molded using this (Examples 1 to 13). And, in the resin molded product,
Flexural modulus (kg / cm ² ), heat distortion temperature (° C), 23
The Izod impact strength at 0 ° C. (kg · cm / cm) and the ridge height (μm) of the weld were measured. Tables 1 to 3 show the proportions of the respective components and the measurement results. In addition, in the same table, for comparison, the component ratios and the like are not shown in Comparative Examples C1 to C1.
C10 is also shown. The following components were used for each component shown in the table. As the polypropylene resin of the component A of the present invention, polypropylene and a modified polypropylene polymer were used.

As the former polypropylene, a crystalline ethylene / propylene / block copolymer containing 7% by weight of ethylene was used. These had a melt flow rate of 15, 30, 45 or 80 (g / 10 min). As the modified polypropylene polymer, a maleic anhydride-modified crystalline polypropylene (homo) was used.

Next, as the resin-coated glass fiber, a glass fiber having a diameter of 15 to 20 μm and a length of 6 to 7 mm, and a bundle of the glass fibers impregnated with a polypropylene resin was used. As the polypropylene resin, a crystalline ethylene / propylene / block copolymer having a melt flow rate of 45 (g / 10 minutes) shown in the component A was used. In addition, this resin-coated glass fiber is a cylindrical pellet,
The length was 6 to 7 mm (same as the glass fiber length), and the pellet diameter was 2 × 3 mm (oval). Further, the glass fiber content in the resin-coated glass fiber is 50% by weight.

In Example 10, a glass fiber having a length of 3 to 3.5 mm (pellet length) was used. In Comparative Example C10, 15% of a glass fiber chopped strand having a diameter of 13 μm and a length of 3 mm and 5% of a glass fiber chopped strand having a diameter of 13 μm and a length of 6 mm were used. Next, the glass fiber of the C component has a diameter of about 13 μm.
m, a chopped strand having a length of 3 mm was used.

In Tables 1 to 3, the column of resin-coated glass fiber is indicated by the total amount of glass fiber and polypropylene resin constituting the resin-coated glass fiber, and the glass fiber accounts for 50% as described above. is occupying. Therefore, in the column of the total amount of glass fibers G in the table, the total amount of 50% of the glass fibers in the resin-coated glass fibers and the amount of the glass fibers of the C component is shown.

Next, the flexural modulus shown in the same table is ASTM-
D790, heat deformation temperature is ASTM-D648 (18.6
kg / cm ² load), Izod impact strength is ASTM-
It was measured according to D256 (notched). As shown in FIG. 3, the height of the weld portion was measured by molding a box-shaped resin molded product with the double gates 71 and 72, and measuring the height of the weld portion 93 at the weld portion 93 as shown in FIG. . In this measurement, a surface roughness meter [Surfton 550AD, Tokyo Seimitsu Co., Ltd.] was used.

Next, the measurement results will be described. First, FIG. 1 shows the total amount G of glass fibers and the polypropylene resin (P) for Examples 1 to 9 and Comparative Examples C1 to C6.
The relationship between P) and the melt flow rate M (g / 10 minutes) was plotted. In each of the examples, the swelling height (μm) of the weld portion was indicated by a numerical value surrounded by a circle for the example and a numerical value surrounded by a square for the comparative example.

As can be seen from the figure, Examples 1 to 9 according to the present invention have a peak height of less than 33 μm, while Comparative Examples C1 to C3, C5 and C6 have a peak height of 37 or more. . Then, a relationship line of M = 1000 / G can be drawn at the boundary between the two as shown in FIG. In Comparative Example C4, the total amount G of glass fibers was 40%.
And the peak height is 39 μm. From the above, M <
In the case of 1000 / G and the glass fiber total amount of 35% or less, it is understood that the swelling height is 35 μm or less.

Next, FIG. 2 plots the Izod impact strength and the swelling height for Examples 2, 6, 9 and Comparative Examples C7, C8, and C9. As can be seen from FIG. 1 and Tables 1 to 3, according to the present invention, it is understood that the impact strength is improved even at the same ridge height.
For example, Example 2 of the present invention has almost the same swelling height as Comparative Example C7, but the impact strength of Example 2 shows a high value, and Comparative Example C7 has a considerably low impact strength and has a practical problem. . That is, according to the present invention, the rising height is suppressed low,
In addition, the impact strength can be increased.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a swelling height of a weld portion in a relationship between a total amount of glass fibers and a melt flow rate of a polypropylene resin in Examples.

FIG. 2 is an explanatory diagram showing a relationship between an Izod impact strength and a swelling height of a weld portion in the embodiment.

FIG. 3 is an explanatory diagram of a weld portion in the embodiment.

FIG. 4 is an explanatory diagram of a swelling height of a weld portion along a line YY in FIG. 3;

FIG. 5 is an explanatory view of a weld portion in various resin molded products shown in a conventional example.

FIG. 6 is an explanatory diagram of a swelling of a weld portion shown in a conventional example.

[Explanation of symbols]

 7,9. . . Resin molded product, 93. . . 7. Weld part, . . Climax, 82. . . Glass fiber,

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 23/00 C08L 23/00 23/10 23/10 23/26 23/26

Claims (6)

[Claims] 1. A polypropylene resin component and a glass fiber, wherein the amount of the polypropylene resin component is 65% by weight or more, the glass fiber amount G is 35% by weight or less, and the polypropylene resin component is Melt flow rate M (g / 10 minutes) and the above glass fiber amount G
(% By weight) means that the relationship of M <1000 / G is satisfied.
A resin molded article for automobiles, which is molded from a glass fiber reinforced polypropylene resin composition. 2. A resin molded article for automobiles according to claim 1, wherein said polypropylene resin component comprises polypropylene and modified polypropylene. 3. The resin molded article for automobiles according to claim 1, wherein the polypropylene resin component is added with an olefin-based or styrene-based elastomer. 4. The resin molded article according to claim 2, wherein the polypropylene contains 3 to 12% by weight of an ethylene component. 5. The resin molded article for automobiles according to claim 2, wherein said modified polypropylene is modified with an acid anhydride. 6. The glass fiber reinforced polypropylene resin composition according to claim 1, wherein the filler component comprises at least one selected from the group consisting of talc, calcium carbonate, mica, barium sulfate, whisker, and clay. A resin molded article for automobiles, characterized by containing: