JPH0559233A - Synthetic resin part for air intake system of internal of combustion engine - Google Patents

Abstract

PURPOSE:To provide the title part which is excellent in vibration-damping properties over a wide temp. range from low to high temps. as well as in mechanical strengths and heat resistance. CONSTITUTION:The title parts such as an air hose 1, a resonator 2, an air cleaner 3, and an air duct 4 are made from a polypropylene resin compsn. obtd. by compounding 100 pts.wt. resin mixture consisting of 50-95wt.% polypropylene resin and 5-50wt.% thermoplastic elastomer mainly comprising a styreneisoprene-styrene block copolymer having a polyisoprene block of a vinyl structure with 10-150 pts.wt. inorg. filler.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to synthetic resin parts such as an air hose, a resonator, an air cleaner and an air duct which constitute an intake system of an internal combustion engine, and more particularly to improving vibration damping performance of the parts.

[0002]

2. Description of the Related Art In recent years, in the field of automobiles, in order to meet the social demand for weight reduction and improvement of fuel consumption,
A part of the component parts is being converted from metal to synthetic resin, and its practical application is progressing. The intake system of an internal combustion engine is no exception, and various intake system components such as air hoses, resonators, air cleaners, and air ducts are made of synthetic resin. The most common synthetic resin is polypropylene resin, which is inexpensive and well balanced in various physical properties. In particular, a reinforced polypropylene resin obtained by adding an inorganic filler composed of a single substance or a mixture of talc, glass fiber, calcium carbonate or the like to a polypropylene resin has excellent strength and heat resistance.

On the other hand, the intake system of an internal combustion engine is required to reduce noise in order to make the interior of the vehicle comfortable and to protect the environment outside the vehicle, in addition to reducing the weight. Of the noise components, the intake noise caused by the pulsation of intake air can be considerably reduced by the silencing by the secondary action of the air cleaner and the silencing by the resonance action or interference action of the resonator.

[0004]

However, in addition to the intake sound, the noise component of the intake system includes a vibration sound generated by the vibration of parts such as an air hose, a resonator, an air cleaner, and an air duct. , There was almost no countermeasure against this vibration noise. In order to reduce this vibration noise, it is necessary to improve the vibration damping performance of the component, and for that purpose, the component may be made of synthetic resin having good vibration damping performance. Although there are few synthetic resins having improved vibration damping performance at present, for example, there is a polypropylene resin composition described in JP-A-62-43443.

However, when the polypropylene resin composition is applied to an intake system synthetic resin component used in a relatively wide temperature range from room temperature to 100 ° C., its mechanical strength, heat resistance and vibration damping performance are improved. Is still insufficient. Further, when an inorganic filler such as talc is added to the polypropylene resin in order to improve mechanical strength and heat resistance, the vibration damping performance (loss coefficient) of the polypropylene resin is lowered as described later.

An object of the present invention is to solve the above-mentioned problems and to have an excellent vibration damping performance in a wide temperature range from a low temperature to a high temperature, and to have an excellent mechanical strength and heat resistance. An object is to provide a synthetic resin part.

[0007]

In order to achieve the above object, the intake system synthetic resin component of an internal combustion engine according to the present invention comprises 50 to 95% by weight of polypropylene resin and 5 to 50% by weight of thermoplastic elastomer. Made of a polypropylene resin composition in which 10 to 150 parts by weight of an inorganic filler is mixed with 100 parts by weight of a resin component obtained from the above, and the thermoplastic elastomer is a styrene-containing polyisoprene block having a vinyl structure. It is characterized in that it is mainly composed of a block polymer having an isoprene-styrene structure.

As the above-mentioned "polypropylene resin", in addition to homopolypropylene, propylene-ethylene random copolymer (ethylene content 20% by weight or less), propylene-ethylene block copolymer (ethylene content 20% by weight or less) and these There is a mixture of. Further, a modified polypropylene resin (a polypropylene resin modified in the presence of an unsaturated carboxylic acid or its derivative and an organic peroxide; the same applies hereinafter) may be partially blended and used.

Further, it is preferable to mix and use the above polypropylene resin and modified polypropylene resin. At this time, the modified polypropylene resin has 1 to 2 in the resin component.
0% (weight ratio, the same applies hereinafter) is preferably contained.
The polypropylene resin preferably has a melt flow index of 5 to 50. When the melt flow index is less than 5, the molding processability and the appearance of the molded product are deteriorated, and when it exceeds 50, the impact resistance is significantly deteriorated.

The above "thermoplastic elastomer" is
As described above, a styrene-isoprene-styrene structure having a vinyl structure polyisoprene block (hereinafter referred to as S
It is called IS structure. ) Is mainly composed of a block polymer. This block polymer is represented by the following general formula, and the polyisoprene block has a 1,2-vinyl bond (formula 1) or a 3,4 vinyl bond (formula 2).
There is.

[0011]

[Chemical 1]

[0012]

[Chemical 2]

The term "main body" means that the block polymer is contained in the thermoplastic elastomer in an amount of 60% or more. In addition, the thermoplastic elastomer has rubber elasticity as well as thermoplasticity, and has compatibility with various plastics. In addition, SI of the above vinyl structure
The S structure is based on Cis or Tra shown in Comparative Example 6 described later.
This is different from the SIS structure of ns-1,4 bond (Formula 3 and Formula 4).

The polypropylene resin is contained in the resin component in an amount of 50 to 95%. Below 50% mechanical strength,
The heat resistance is lowered, and if it exceeds 95%, the vibration damping performance is lowered. The thermoplastic elastomer is contained in the resin component in an amount of 5 to 50%. If it is less than 5%, the vibration damping performance is low,
If it exceeds 50%, heat resistance and mechanical strength may decrease.

Next, as the "inorganic filler", talc, glass fiber, mica, wollastonite, barium sulfate, clay, calcium carbonate, carbon fiber, silicon carbide fiber, potassium whisker titanate, calcium sulfate whisker Etc. are used. A polyurethane resin composition is prepared by mixing 10 to 150 parts by weight of the inorganic filler with 100 parts by weight of the resin component. If it is less than 10 parts by weight, the vibration damping performance is low especially near room temperature, and the mechanical strength is lowered,
If it exceeds 50 parts by weight, the mechanical strength is improved, but the vibration damping performance may be deteriorated.

Further, among the above-mentioned inorganic fillers, talc, mica and calcium carbonate exhibit more excellent vibration damping performance. Particularly, it is preferable to use talc having an average particle size of 1 to 20 μm from the viewpoint of mechanical strength, heat resistance and workability. If it is less than 1 μm, it becomes bulky and the mixing property with the crystalline polypropylene resin is lowered, and if it exceeds 20 μm, the dispersibility of talc becomes insufficient and sufficient reinforcing strength cannot be obtained. It is more preferable to use one having a thickness of 1 to 15 μm, and particularly to use one having a thickness of 1.5 to 5 μm when high strength and high rigidity are required.

Next, the above "polypropylene resin composition"
Can be produced using a normal kneader such as a single-screw extruder, a twin-screw extruder, a kneader, a Brabender, or a Banbury mixer. Usually, each blending component is mixed in a predetermined ratio by a tumbler type blender, a Henschel mixer, a ribbon mixer, etc., and then kneaded with an extruder or the like to form a pelletized compound, and then an air hose, a resonator, an air cleaner, Process into the shape of intake system synthetic resin parts such as air ducts. Further, in the above kneading, a part or all of the inorganic filler such as talc may be supplied midway in the middle of the cylinder of the extruder.

In the polypropylene resin composition, in addition to the above components, an antioxidant, an ultraviolet absorber, a lubricant, an antistatic agent, a nucleating agent, a pigment, a flame retardant, an extender,
You may mix additives, such as a processing aid.

[0019]

ACTION AND EFFECT Since the intake system synthetic resin part of the present invention is made of the above polypropylene resin composition,
It has the following effects. Wide temperature range from low to high (eg
At room temperature to 100 ° C, excellent vibration damping performance (for example,
The loss factor is 0.04 to 0.18). Further, its vibration damping performance is excellent especially near room temperature. It has excellent mechanical strength, and even if the amount of the inorganic filler is increased to improve the mechanical strength, the vibration damping performance does not decrease (for example, Examples 1 to 4 and Comparative Examples 3 to 5). See.). Has excellent heat resistance.

[0020]

EXAMPLES Examples and comparative examples of the present invention embodied in an intake system synthetic resin component of an internal combustion engine as shown in FIG. 1 will be described below. First, the assumptions will be described. The physical properties of the vibration-damping resin were measured by the following methods. Also, the compounding ratios of the components and the measurement results of the test pieces in each example are shown in each table. Also, the mixing ratio is
The resin component consisting of a polypropylene resin and a thermoplastic elastomer is shown in% by weight. Further, the ratio of the resin component and the inorganic filler is indicated by parts by weight of the inorganic filler with respect to 100 parts by weight of the resin component.

(A) Flexural Modulus (kgf / cm 2) It was measured according to ASTM D790. (B) Izod impact value (kgfcm / cm) It was measured according to ASTM D256. (C) Heat distortion temperature (° C) Load according to ASTM D648 18.6 kg / cm2
Went by. (D) Loss factor A square plate having a length and width of 150 mm and a thickness of 3 mm was prepared by injection molding, and the center of the plate was kept at several temperatures in a constant temperature bath capable of raising the temperature from room temperature to 100 ° C. The part was vibrated at 0.1 G and the transfer function was measured. And 1
The loss coefficient was calculated from the next resonance point by the half-width method.

The test pieces shown in Examples and Comparative Examples were prepared by mixing the compositions mixed in a predetermined ratio by melt-kneading with a twin-screw extruder with different directions, and length L / diameter D = 27 mm, 30 mm.
And pellets. The pellets are then placed at 80 ° C for 3
After drying for an hour, it was molded by a 5oz injection molding machine to prepare a test piece.

Now, examples and comparative examples of the intake system synthetic resin parts will be described with reference to FIG. 1 and Tables 1 to 3. Figure 1
In FIG. 1, 1 is an air hose for taking in outside air, 2 is a resonator (silencer) connected to the air hose 1, 3 is an air cleaner connected to the resonator 2, and 4 is an air duct connected to the air cleaner 3. Further, 5 is a fuel injection device connected to the air duct 4, and 6 is an internal combustion engine body connected to the fuel injection device 5. In the following,
PP indicates polypropylene resin, and VS indicates the thermoplastic elastomer. As the polypropylene resin, J800 of Mitsui Petrochemical Co., Ltd. was used. As the thermoplastic elastomer, VS-1 manufactured by Kuraray Co., Ltd. was used. The types of inorganic fillers are shown in the table.

[Examples 1 to 4 and Comparative Example 1] In this example, PP
The air hose 1 of FIG. 1 is injection-molded using a vibration damping resin obtained by mixing talc in various parts by weight with 100 parts by weight of a resin component consisting of 70% and VS30%. The talc used had an average particle size of 1.6 to 2.0 μm. As is known from Table 1, when talc as an inorganic filler is added, the loss coefficient becomes large at 23 ° C., which is around room temperature, and vibration damping performance is improved, as compared with Comparative Example 1 in which talc is not added. I know what to do. And
It can be seen that the damping performance on the high temperature side is further improved as the amount of talc increases. Moreover, the flexural modulus increases as the amount of talc increases, while the Izod impact value decreases. The heat resistance of the above test is about 55 ° C.

In order to confirm the above effect, a small piece (not shown) was cut out from the air hose 1 of each of Examples 1 to 4 and Comparative Example 1, a vibration pickup was attached, and the vibration level when the small piece was blown by a blower was examined. .. As a result, in most of the wide frequency range of 50 to 1000 Hz, the vibration level of the air hose 1 of Examples 1 to 4 was lower than that of the air hose 1 of Comparative Example 1 to 5 dB (decibel).

[0026]

[Table 1]

[Examples 5 to 7 and Comparative Example 2] This example is made of PP.
A resonator 2 of FIG. 1 is injection-molded using a vibration damping resin obtained by mixing talc in various parts by weight with 100 parts by weight of a resin component consisting of 80% and VS20%. As is known from Table 2, the tendency of changes in physical properties depending on the mixing ratio of the resin component and talc is the same as in Table 1 above. On the other hand, in this example, since the amount of VS in the resin component is smaller than that in the previous example (Table 1), it can be seen that the loss coefficient is lower than in the previous example. Moreover, the heat resistance is slightly improved from the previous example.

[0028]

[Table 2]

[Examples 8 to 11 and Comparative Examples 3 to 6] In Examples 8 to 9, the vibration damping resin using mica or calcium carbonate in place of talc in Example 2 was used.
The air cleaner 3 is manufactured by injection molding. In addition, Examples 10 to 11 are a mixture of mica and talc instead of talc in Example 2 or glass fiber (GF).
The air duct 4 of FIG. 1 is injection-molded using a vibration-damping resin that uses a mixture of talc and talc.

Comparative Example 3 is PP only, Comparative Examples 4 and 5 are
Is an example in which VS is not added. Further, in Comparative Example 6, V
In this example, SS is used instead of S. Here, SS is different from the above-mentioned specific "thermoplastic elastomer mainly composed of a block polymer having a SIS structure having a polyisoprene block having a vinyl structure" used in the present invention, and as described below, Cis-1,4 bond ( Chemical formula 3) or Trans-
It is a thermoplastic elastomer mainly composed of a block polymer of SIS structure having a polyisoprene block of 1,4 bond (Formula 4). For this SS, "SIS5000" manufactured by Nippon Synthetic Rubber Co., Ltd. was used.

[0031]

[Chemical 3]

[0032]

[Chemical 4]

As is known from Tables 3 and 4, Examples 8 to 11 according to the present invention all show a high loss coefficient. On the other hand, it is understood that Comparative Examples 3 to 6 to which VS is not added all have a low loss coefficient. And, when VS is not added as in Comparative Examples 3 to 5 (Table 4), if the amount of talc as the inorganic filler increases,
It can be seen that the loss coefficient tends to decrease. In this regard, in the present invention, Comparative Example 1 and Example 1
~ 4, as known from Comparative Example 2 and Examples 5 to 7, since VS is added, even if the amount of talc increases,
It can be seen that the loss coefficient does not decrease. Further, it can be seen that the mechanical strength increases as the amount of talc increases.

Further, as known from Comparative Example 6 in Table 3,
It can be seen that when the SS and PP having the Cis or Trans-1,4 bond are used, the loss coefficient is considerably lower than that when VS and PP are used (for example, Examples 8 to 11). .. This means that the thermoplastic elastomer having a vinyl structure according to the present invention is
It is shown that it greatly contributes to the improvement of the vibration damping performance as compared with the bonded thermoplastic elastomer.

[0035]

[Table 3]

[0036]

[Table 4]

The present invention is not limited to the configuration of the above-described embodiment, and may be modified and embodied without departing from the spirit of the invention.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an intake system synthetic resin component embodying the present invention.

[Explanation of symbols]

 1 Air hose 2 Resonator 3 Air cleaner 4 Air duct

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location F02M 35/024 M 9247-3G 35/10 101 D 9247-3G H 9247-3G 35/12 B 9247 −3G (72) Inventor Daisuke Tsutsumi 1 Nagachihata, Ochiai, Kasuga-cho, Nishikasugai-gun, Aichi Prefecture, Toyoda Gosei Co., Ltd.

Claims (1)

[Claims] 1. A synthetic resin part constituting an intake system of an internal combustion engine, wherein the synthetic resin part is 100 parts by weight of a resin component obtained by mixing 50 to 95% by weight of a polypropylene resin and 5 to 50% by weight of a thermoplastic elastomer. 10 parts of inorganic filler
It is made of a polypropylene resin composition containing 150 parts by weight, and the thermoplastic elastomer is mainly composed of a styrene-isoprene-styrene structure block polymer having a vinyl structure polyisoprene block. Intake system synthetic resin parts for internal combustion engines.