JP2812550B2 - Polypropylene resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polypropylene resin composition having excellent vibration damping performance.

(Prior art)

In recent years, with respect to automobiles, in response to social demands for improved fuel efficiency and reduced weight, some of the components have been being converted from metal to plastic, and their practical use has been progressing.

Among plastic materials, polypropylene resin is a material having a balance of various physical properties and is relatively inexpensive, so that it is used in large quantities in interior and exterior parts of automobiles. In particular, reinforced polypropylene resin in which inorganic fillers such as talc, glass fiber, calcium carbonate and the like and a mixture thereof are filled in polypropylene resin is excellent in strength and heat resistance. Therefore, timing belt cover, blower case, cooler housing. , Ducts, etc.

On the other hand, in recent years, in addition to reducing the weight of automobiles, reduction of noise has been strongly desired in order to create a comfortable environment in the vehicle interior.

Measures to control noise include vibration suppression, sound insulation, vibration isolation, sound absorption, etc.
Alternatively, a countermeasure method differs depending on whether the contribution of the air transmitted sound is large. Therefore, in order to reduce noise by replacing the material, it is necessary to improve the vibration control performance of the material.

Conventionally, as a polypropylene resin composition having improved vibration damping performance, there is an invention described in JP-A-62-43443.

[Problem to be solved]

However, when the above polypropylene resin composition is used in a relatively wide temperature range, for example, from room temperature to 80 ° C., its vibration damping performance is still insufficient.

The present invention has been made as a result of intensive studies in view of the above problems, and aims to provide a polypropylene resin composition that exhibits excellent vibration damping performance in a wide temperature range from low to high temperatures. is there.

[Solutions to solve the problem]

The present invention relates to a thermoplastic elastomer comprising 50 to 90% by weight of a polypropylene resin, 5 to 45% by weight of a thermoplastic elastomer, and 5 to 20% by weight of an aromatic or aliphatic petroleum resin. Is a polypropylene resin composition characterized by being mainly composed of a styrene-isoprene-styrene block polymer having a polyisoprene block having a vinyl structure.

The most remarkable point in the present invention is that the polypropylene resin, the specific thermoplastic elastomer having the polyisoprene block, and the petroleum resin are mixed in the above ratio to obtain a polypropylene resin composition.

As the polypropylene resin, it is preferable to use a crystalline polypropylene resin. As the crystalline polypropylene resin, there are a so-called polypropylene resin and a modified polypropylene resin.

As the former polypropylene resin, besides homopolypropylene, a propylene-ethylene random copolymer (ethylene content of 20% by weight or less), a propylene-ethylene block copolymer (ethylene content of 20% by weight or less) and a mixture thereof are used. . The latter modified polypropylene resin is obtained by modifying a polypropylene resin and an unsaturated carboxylic acid or a derivative thereof in the presence of an organic peroxide.

Thus, as the crystalline polypropylene resin, it is preferable to use a mixture of the above polypropylene resin and a modified polypropylene resin. At this time, the modified polypropylene resin is preferably contained in the resin component at 1 to 20% (the same applies to the weight ratio or less). The melt flow index of the crystalline polypropylene resin is preferably 5 to 50. If the melt flow index is less than 5, the moldability and the appearance of the molded article are deteriorated. If the melt flow index exceeds 50, the impact resistance is significantly reduced. .

Further, the thermoplastic elastomer is, as described above,
It is mainly composed of a block polymer having a styrene-isoprene-styrene structure (SIS structure) having a polyisoprene block having a vinyl structure.

The block polymer is represented by the following general formula, wherein the polyisoprene block has a 1,2-vinyl bond (Formula 1)
Or, those having a 3,4-vinyl bond (Formula 2).

The term "main component" means that the thermoplastic polymer contains the block polymer in an amount of 60% or more. Further, the thermoplastic elastomer has thermoplasticity and rubber elasticity, and has compatibility with various plastics.

The petroleum resin includes an aromatic or alicyclic resin. The aromatic petroleum resin is shown below (Formula 3)
The alicyclic petroleum resin is represented by the following (Formula 4). In both formulas, R and R ₁ represent H or CH ₃ .

The content of the above polypropylene resin is 50 to 90%. 50
If it is less than 90%, the mechanical strength and heat resistance decrease, whereas if it exceeds 90%, the vibration damping performance decreases.

Further, the thermoplastic elastomer is contained in an amount of 5 to 45%. If it is less than 5%, the vibration damping performance is low, while if it exceeds 45%, heat resistance and mechanical strength may be reduced.

The content of the petroleum resin is 5 to 20%. If it is less than 5%, the effect of improving the vibration damping performance is low, while if it exceeds 20%, the functional strength, especially the impact strength, is significantly reduced.

Further, the content of the polypropylene resin is preferably 60 to 80%, the content of the thermoplastic elastomer is 10 to 30%, and the content of the petroleum resin is preferably 5 to 15%. As a result, a material having a good balance between vibration damping performance and mechanical strength can be obtained.

Next, the above-mentioned polypropylene resin composition can be produced using a usual kneader such as a single-screw extruder, a twin-screw extruder, a kneader, a Brabender, and a Banbury mixer. Usually, each compounded component is mixed at a predetermined ratio by a tumbler type blender, Henschel mixer, ribbon mixer, etc., and then kneaded by an extruder or the like to form a pellet-shaped compound. Thereafter, a timing belt cover, an air blower case, It is formed into a desired shape of a molded product such as a heater housing.

In the present invention, in addition to the above components, additives such as inorganic fillers, antioxidants, ultraviolet absorbers, lubricants, antistatic agents, nucleating agents, pigments, flame retardants, extenders, and processing aids are mixed. You may. Examples of the inorganic filler include talc, calcium carbonate, and glass fiber.

The polypropylene resin composition of the present invention can be used for various components in an automobile engine room, interior and exterior components for automobiles, or other electric components and mechanical components. It is particularly suitable for components that generate vibration noise in the engine room of an automobile, for example, a timing belt cover, a gear cover, an air cleaner case, or an air conditioner such as an air blower case and a duct.

In addition, parts that may generate noise such as squeaks, such as instrument panels, garnishes,
It is also suitable for clusters, console boxes, and the like.

[Action and effect]

In the present invention, a polypropylene resin composition is constituted by the above composition.

Therefore, the polypropylene resin composition of the present invention has excellent performance (for example, a loss coefficient of 0.06 or more) with respect to the vibration damping performance at room temperature to 80 ° C., which has conventionally been a problem. And, the above-mentioned vibration damping performance is particularly excellent near normal temperature.

As described above, according to the present invention, it is possible to provide a polypropylene resin composition exhibiting excellent vibration damping performance in a wide temperature range from a low temperature to a high temperature.

〔Example〕

Hereinafter, Examples and Comparative Examples according to the polypropylene resin composition of the present invention will be described.

The loss factor was measured by the following method. Also,
The proportions of the components and the measurement results of the test pieces in each example are shown in the following table. The above mixing ratio is shown by weight%.

Loss factor: A square plate of 150 mm in both length and width and a thickness of 3 mm is manufactured by injection molding, and the center of the plate is vibrated at 0.1 G in a constant temperature bath capable of raising the temperature from room temperature to 100 ° C. The transfer function was measured. Then, the loss factor was calculated from the primary resonance point by the half-width method.

Further, in the preparation of the test pieces listed in Examples and Comparative Examples, the compositions mixed in a predetermined ratio were melt-kneaded with a different-direction rotary twin-screw extruder having a length L / diameter D = 27 mm and 30 mm to obtain pellets. Next, the pellets were dried at 80 ° C. for 3 hours, and then molded using a 5 oz injection molding machine to prepare test pieces.

Next, Examples and Comparative Examples will be described with reference to Tables 1 and 2. In the following, PP is a crystalline polypropylene resin, VS is the thermoplastic elastomer, M1, M
2 shows the following petroleum resins.

The PP used was Hypol (registered trademark) J800 of Mitsui Petrochemical Co., Ltd. VS-1 of Kuraray Co., Ltd. was used as the thermoplastic elastomer.

Further, in the same table, M-1 and M-2 indicate petroleum resins.
As M-1, Neopolymer (registered trademark) 120 of Nippon Petrochemical Co., Ltd. was used, and as M-2, Alcon (registered trademark) M-115 of Arakawa Chemical Co., Ltd. was used.

As can be seen from Table 1, Examples 1 to 1 according to the present invention are shown.
4 shows a high loss coefficient.
On the other hand, in Comparative Example 1 in which VS and M-1 and M-2 were not added,
It can be seen that the loss factor is low. Further, it can be seen that Examples 1 to 4 have higher vibration damping performance especially in the low-temperature region than Comparative Example 1.

In Comparative Examples 2 to 4, M-1 or M-1 was used without adding VS to PP.
-2, but as known from Table 2,
It can be seen that excellent vibration damping performance cannot be exerted by using only the both as in Examples 1 to 4 of the present invention.

────────────────────────────────────────────────── (5) References JP-A-2-300250 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08L 23/00-23/36 C08L 53 / 02 C08L 57/02

Claims (1)

(57) [Claims] 1. A mixture of 50 to 90% by weight of a polypropylene resin, 5 to 45% by weight of a thermoplastic elastomer, and 5 to 20% by weight of an aromatic or alicyclic petroleum resin. A polypropylene resin composition characterized in that the plastic elastomer is mainly composed of a block polymer having a styrene-isoprene-styrene structure having a polyisoprene block manufactured by vinyl.