JPH01262113A - Manufacture of reinforced polypropylene resin molded form - Google Patents

Abstract

PURPOSE:To obtain excellent vibration-damping performance and high mechanical strength and heat resistance by molding to a desired shape a reinforced polypropylene resin composition acquired by mixing a first granular body obtained by melting and kneading a crystalline polypropylene resin, a mixture of a specific copolymer and a specific resin and a component containing talc and the second granular body of a glass-fiber-reinforced polypropylene resin. CONSTITUTION:The three components of 28.5-73wt.% crystalline polypropylene resin having a melt flow index of 5-50, 2.5-28wt.% mixture at the mixing ratio of 1:4-4:1 of an ethylene-alpha olefin copolymer and an aromatic hydrocarbon resin and 15-45wt.% talc having means grain size of 1-20mum are mixed, and melted and kneaded, thus manufacturing a first granular body. The 50-95wt.% first granular body and the 5-50wt.% second granular body of a glass-fiber- reinforced polypropylene resin, which includes 20-40wt.% glass fiber and in which the total quantity of talc and glass fiber is brought to 50wt.% or less in all compositions, are mixed at 100 deg.C or lower, thus preparing a reinforced polypropylene resin composition. The composition is molded to a desired shape by an injection molding machine, etc.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to a double-reinforced polypropylene which has excellent vibration damping performance in a wide temperature range from low to high temperatures, and has high mechanical strength and heat resistance. Regarding resin molded products.

[Prior art]

In recent years, in response to the social demand for improved fuel efficiency in automobiles, research has been actively conducted on changing the component parts of automobiles from metal to plastic, and the practical use of this technology is also progressing.

Polypropylene resin is a plastic material.

It is a material with well-balanced physical properties and is relatively inexpensive, so it is used in large quantities for interior and exterior parts of automobiles. And especially talc.

Reinforced polypropylene resin, which is made by filling polypropylene resin with fillers such as glass fiber, carbonate, lucium, etc., and a mixture thereof, has excellent 3-strength and heat resistance.
It is actively applied to various molded parts in the engine compartment that are used in relatively high temperature atmospheres, such as timing belt covers, gear covers, fan shrouds, and air cleaner cases.

On the other hand, in recent years, automobiles have been required not only to be lightweight but also to reduce noise, and among these, reduction in engine noise is particularly strongly desired. Countermeasures against noise include vibration damping, sound insulation, vibration proofing, sound absorption, etc., and the countermeasures differ depending on whether engine noise has a large contribution from solid-borne sound or air-transmitted sound. Particularly in engine peripheral parts such as a timing belt cover that covers the outside of the timing belt or a gear cover, the main source of noise is often the contribution of solid-borne sound during boat fishing, although this varies depending on the vehicle model and engine type. Therefore, in order to reduce noise by replacing materials, it is necessary to improve the vibration damping performance of the materials.

Conventionally, as a polypropylene resin molded product with improved vibration damping performance, there is an invention described in JP-A-62-43443. This product is a mixture of a tackifier resin such as coumaron-indene resin, a thermoplastic elastomer, and a polypropylene resin.

[Problem to be solved]

However, when the reinforced polypropylene resin molded product described in the above-mentioned publication is applied to engine peripheral parts used at relatively high temperatures of 40 to 100°C, it is difficult to improve its mechanical strength, heat resistance, and vibration damping. Performance is still insufficient.

In general, resin materials have more irregular molecular structures and weaker bonding forces between chains than metal materials, so they exhibit remarkable viscoelastic properties and possess vibration damping performance. However, on the other hand, the temperature dependence is large, and the damping performance is highest around the maximum temperature of the loss tangent of mechanical dispersion, which is mainly based on the glass transition of the resin material.

At temperatures other than those within the practical range, vibration damping performance generally deteriorates significantly. The viscoelastic behavior of polypropylene resin varies depending on the measurement method, resin composition, etc.

The peak of loss tangent based on the glass transition of -S polypropylene resin usually appears in the range of -30°C to around 25°C, and the value of loss tangent decreases significantly after this peak temperature, reaching 50°C. It becomes small at the front and back.

This characteristic also appears in the reinforced polypropylene resin filled with filler, and the absolute value of the loss tangent further decreases over the entire measurement temperature range due to filler filling. This decrease in loss tangent mainly occurs between 40°C and 100°C.
This is the main reason why products used in the temperature range of about °C cannot obtain sufficient vibration damping performance.

Further, 9-reinforced polypropylene resin molded products are required to have high mechanical strength such as bending strength.

The present invention was made as a result of intensive research in view of the above problems, and has excellent vibration damping performance in a wide temperature range from low to high temperatures, and is commonly used at temperatures of 40°C to 100°C.
The object of the present invention is to provide a reinforced polypropylene resin molded product having sufficient mechanical strength and heat resistance to be used in a temperature atmosphere of .

[Means for solving problems]

The present invention relates to a molded article using a triple-reinforced polypropylene resin composition, which is characterized in that a reinforced polypropylene resin composition is produced in the following first and second steps, and then molded in a third step.

“(A) 28.5 to 73% by weight of a crystalline polypropylene resin with a melt flow index of 5 to 50.

(B) consists of an ethylene-α olefin copolymer (X) and an aromatic hydrocarbon resin (Y), and this (X): (
82.5 to 28% by weight of a mixture in which the proportion [weight ratio] of Y) is 1=4 to 4:1.

(C) 15 to 45% by weight of talc with an average particle size of 1 to 20 μm
.

A first step of mixing the three components and melting and kneading the mixture to form a first granule.

50 to 95% by weight of the first granules obtained in the first step, and (
D) Second granules 5 of glass fiber reinforced polypropylene resin
-50% by weight at 100°C or lower to prepare a reinforced polypropylene resin composition.

The third step consists of molding the reinforced polypropylene resin composition obtained in the second step into a desired shape using an injection molding machine or the like.

The glass fiber reinforced polypropylene resin contains 20 to 40% by weight of glass fibers, and the total amount of talc and glass fibers is 50% by weight or less in the entire composition. A method for producing a resin molded article, that is, 2, the present invention is a method for producing a resin molded article, in which the above-mentioned (A) component 28
．． 5 to 73% (weight ratio, same hereinafter), component (B) 2.5 to 28%, and component (C) 15 to 45%.
First step) 9 Next, this first granule 50
95% and 5 to 50% of the second granules (Component D) of glass fiber reinforced polypropylene resin prepared separately to form a reinforced polypropylene resin composition (2nd step), which is a retentate reinforced polypropylene resin. The composition is molded into a molded article of a desired shape (third step).The ratio of each of the above components is the proportion in the reinforced polypropylene resin composition obtained in the second step (however, (except for the 20-40% glass fibers in the glass fiber reinforced polypropylene resin) and each component is unique as described above.

These will be explained below.

In the present invention, the melt flow index is 5 to 5.
0 crystalline polypropylene resin is used.

This crystalline polypropylene resin includes so-called polypropylene resin and modified polypropylene resin. As the former polypropylene resin, in addition to homopolypropylene, propylene-ethylene random copolymers, propylene-ethylene block copolymers, and mixtures thereof are used. Also.

The latter modified polypropylene resin is a polypropylene resin modified with an unsaturated carboxylic acid or its derivative and an organic peroxide.

However, as a crystalline polypropylene resin.

In this case, it is preferable to use a mixture of this polypropylene resin and a modified polypropylene resin.

It is preferable that the modified polypropylene resin is contained in the resin component (the A component and the day component) in an amount of 1 to 20%.
If the above-mentioned melt flow index is less than 5, the molding processability and appearance of the molded product will be poor, and if it exceeds 50, the impact resistance will be significantly reduced.

The crystalline polypropylene resin is blended in an amount of 28.5 to 73% in the 9-reinforced polypropylene resin composition. This blending amount is determined from the optimum blending amounts of the ethylene-α olefin copolymer, aromatic hydrocarbon resin, talc, and glass fiber-reinforced polypropylene resin, which will be described below.

Next, what is ethylene-α-olefin copolymer?

Propylene, butene-1, hexene-1, decene-1,
It uses α-olefin such as 4-methylbutene-1,4-methylpentene-1 as a copolymerization component. Among these,
When the α-olefin is propylene, particularly excellent vibration damping performance is exhibited.

Further, the aromatic hydrocarbon resin is a petroleum resin represented by a linear formula.

(In the above formula, R, R, represent H or CH.

n indicates the degree of polymerization. ) Polymerization degree exhibiting a softening point of 80° C. to 170° C. is usually used.

The ethylene-α olefin copolymer and the aromatic hydrocarbon resin are at least partially compatible.

It is important that the maximum loss tangent or glass transition temperature of the mixture is within the operating temperature range.

For this purpose, it is necessary to adjust the phase mW of both. Type and amount of ethylene-α olefin copolymer,
By controlling the softening point and usage amount of the aromatic hydrocarbon resin, it is possible to obtain the optimum vibration damping performance state for the temperature conditions.

The composition ratio of the ethylene-α olefin copolymer (X) and the aromatic hydrocarbon resin (Y) is 9 weight ratio (X): (
Y)=11 to 4:1. If the amount of the aromatic hydrocarbon resin is less than the above range, the damping performance improvement effect will be small, and if it exceeds the above range, the resin will become brittle and the heat resistance will decrease.

"Mixture B" is a mixture of the above ethylene-α olefin copolymer and aromatic hydrocarbon resin.

Use 2.5-28%. If the mixture B is less than 2.5%, the effect of improving vibration damping performance is small, and if it exceeds 28%, the strength and heat resistance are reduced.

The above talc has a structural formula of 3Mg0.4StO and H.
, O, and has an average particle size of 1 to 20 μm from the viewpoint of mechanical strength, heat resistance, and workability. If it exceeds 20 JIm, the dispersibility of talc will be insufficient and a sufficient reinforcing effect will not be obtained, while if it is less than 1 μm, it will become bulky.

Mixability with polypropylene resin decreases. Also.

Preferably, one having a diameter of 1 to 15 μm is used. Furthermore.

Especially when high strength and high rigidity are required, 1.5 to 5 μm
It is preferable to use one. The average particle size here is a value defined by the particle size (D50) on the 50% cross line under the integrating sieve in a particle size distribution curve measured using a centrifugal sedimentation type particle size distribution measuring device.

Thus, 15 to 45% of talc is used. If it is less than 15%, it is difficult to obtain sufficient mechanical strength and heat resistance, and if it exceeds 45%, vibration damping performance or appearance quality of the molded product will deteriorate.

The above three components are melted and kneaded in the first step.
Make it into granules. This first granule has a diameter of 3 m, for example, 1 to 3 m in diameter.
It is made into small columnar granules with a length of 2 to 51 m.

In this first granule, the A, B, and C
The total amount of these three components is adjusted to account for 50 to 95% of the total amount of the 9-reinforced polypropylene resin composition.

Next, the glass fiber reinforced polypropylene resin used in the second step is a second granular body made of crystalline polypropylene resin and glass fiber. As this crystalline polypropylene resin, the same one as mentioned above is used. The amount of glass fiber in this glass fiber reinforced polypropylene resin is 20 to 40%. If it is less than 20%, the mechanical strength and heat resistance of the 9-reinforced polypropylene resin molded product will be low, and -
If it exceeds 40%, the damping performance will deteriorate.

The second granules are prepared by kneading the following glass fibers and crystalline polypropylene resin in a state in which the crystalline polypropylene resin is melted in the same manner as in the case of producing the first granules described below. .

It is made into small columnar granules with a length of 2 to 5 m.

The glass fiber may be any glass fiber used as a reinforcing agent for polypropylene resin.

From long fiber type (glass roving) to short fiber type (
Any shape can be applied, including chopped strands and milled fibers. Of these, chopped strands are most preferred, especially those whose surfaces have been treated with a silane coupling agent. A length of 3 to 6ffI11 is more preferable, and when using chopped strands surface-treated with a silane coupling agent, 1 to 20% of a modified polypropylene resin (in the reinforced polypropylene resin composition) is used as the crystalline polypropylene resin. (content) improves mechanical strength and heat resistance.

Next, the total amount of said talc and glass fibers is calculated as follows:
(reinforced polypropylene resin) so that the amount is 50% or less. If this total amount exceeds 50%, although the mechanical strength and heat resistance are at a sufficient level, it is not preferable because it causes a decrease in vibration damping performance or a decrease in the appearance quality of the product.

Next, each process will be described.

The first step is a step in which the three components (A) to (C) are mixed and melt-kneaded to produce a first granule. This melt-kneading is performed by heating to at least a temperature at which the crystalline polypropylene resin melts.

The first granular material is produced using a -screw extruder or a twin-screw extruder.

It can be produced using a conventional kneading machine such as a Nigu, Flabender, or Banbury mixer.

Usually, each component is mixed in a predetermined ratio using a tumbler blender, Henschel mixer, ribbon mixer, etc., and kneaded using an extruder etc. to form a pellet-like compound. It is also possible to use a two-stage method in which the ethylene-α olefin copolymer and aromatic hydrocarbon resin are melt-kneaded in an extruder in advance, and then the kneaded product, crystalline polypropylene resin, and talc are kneaded and extruded. Further, part or all of the talc may be fed midway between the cylinders of the extruder.

Next, in the second step, 50 to 95% of the first granules created in the first step and 5 to 50% of the second granules (glass fiber reinforced polypropylene resin) are mixed.

A reinforced polypropylene resin composition is prepared by mixing at 100°C or below.

Here, if the first granule content is less than 50%, the damping performance is insufficient, and if it exceeds 95%, the mechanical strength is poor.

Heat resistance decreases. Furthermore, if the mixing temperature exceeds 100°C, problems such as block melting of the granules occur. In addition,
Preferably it is 20-50°C.

Further, the above-mentioned kneading is performed using the above-mentioned mixer, extruder, etc. as in the case of the first granular material. Thus, the thus obtained reinforced polypropylene resin composition is one in which the second granules (glass fiber reinforced polypropylene resin) are scattered in a matrix consisting of the components (A) to (C). It is. Note that this second granular body may be in a slightly collapsed state compared to the initial state.

Next, in the third step, the reinforced polypropylene resin composition is molded into the shape of a desired molded product such as the timing belt cover or gear cover.

Molding methods include injection molding, extrusion molding, and blow molding.

Furthermore, in the present invention, in addition to the above-mentioned components, an antioxidant,
Ultraviolet absorber, lubricant, antistatic agent, nucleating agent.

Additives such as pigments, flame retardants, fillers, processing aids, etc. may be mixed.

[Action and effect]

In the present invention, the reinforced polypropylene resin composition obtained through the above steps is molded into a desired molded article.

Therefore, the molded article of the present invention exhibits high performance (loss tangent of about 0.03 or more) regarding vibration damping performance at relatively high temperatures (40 to 100°C), which has been a problem in the past.

Moreover, even under such temperature, the bending elastic modulus is about 32. 0
It has excellent performance, with a bending strength of 500 kg/cd or more and a heat distortion temperature of about 90°C or more.

Therefore, the reinforced polypropylene resin molded product of the present invention can be used for parts in the engine compartment of automobiles, interior parts, exterior parts,
Can be used for other electrical and mechanical parts. Also,
It is particularly suitable for parts 1 where vibration noise is generated in the engine room of an automobile, such as a timing belt cover, a gear cover, an air cleaner case, etc.

As described above, according to the present invention, it is possible to provide a reinforced polypropylene resin molded product having excellent vibration damping performance, high mechanical strength, and heat resistance.

〔Example〕

Two examples and a comparative example according to the present invention will be described below.

The various physical properties were measured by the following methods. In addition, the blending ratio of the components in each case and the measurement results of the test pieces (molded products) are shown in each table. The above mixing ratio is.

Each weight percentage in the reinforced polypropylene resin composition is shown.

O bending modulus 2 bending strength Testing was conducted according to ASTM 0790.

The test was conducted according to heat distortion temperature ASTM 064B at a load of 18.6 kg/cd.

O Loss Tangent A square flat plate with length and width of 150 mm and thickness of 3 ms was fabricated by injection molding, and the center of the flat plate was vibrated at 0.1 G in a constant temperature bath that can be heated from room temperature to 100°C. and measured the transfer function.

Then, the loss tangent η was calculated from the first-order resonance point using the half-width method.

In addition, the preparation of test pieces listed in Examples and Comparative Examples.

First, the method of mixing the raw materials is slightly different as shown below.
In Examples 1, 3 to 9, the ingredients except the glass fiber reinforced polypropylene resin were combined in a tumbler blender for 5 minutes, and the resulting mixture was
The mixture was melt-kneaded using a 7++ m, 30 mm twin-screw extruder rotating in different directions to obtain a first granule (first step). Next, this first granule and a second granule made of a glass fiber-reinforced polypropylene resin prepared separately were mixed together in a tumbler-type blender.
A pellet of the 1-reinforced polypropylene resin composition was prepared by bonding at 5°C for 5 minutes (second step).

As a third step, the pellet of the reinforced polypropylene resin composition was dried at 80° C. for 3 hours, and then molded using a 5 oz injection molding machine to prepare a test piece.

Example 2. In Comparative Example 3, as shown in Table 1, 1
Both have the same blending ratio in the reinforced polypropylene resin composition, but in Example 2, 5.8% polypropylene resin, 7% modified polypropylene resin, and 2.5% glass fiber, totaling 15.3% (both reinforced The second granules are mixed with the first granules. On the other hand, as shown in parentheses, Comparative Example 3 consisted of 5.8% polypropylene resin, 7% modified polypropylene resin, and 4% ethylene-α olefin copolymer.
．． 2%, aromatic hydrocarbon resin 2.8% and glass fiber 2.
5%, a total of 22.3% (all as percentages in the reinforced polypropylene resin composition), was used, and this was mixed with granules containing only components (A) and (C). The above-mentioned mixing was carried out for 5 minutes by using a tumbler type blender for each of the above two types of granules to form pellets of 1-reinforced polypropylene resin composition. After that.

A test piece was prepared using the same method as in Example 1 (third step).

In Comparative Example 1, all ingredients were combined in a tumbler blender for 5 minutes. The subsequent treatment (third step) is
Same as above.

In Comparative Examples 2 and 4, glass fiber was mixed alone, and all ingredients except glass fiber were blended in a tumbler blender for 4 minutes, and then glass fiber was added and blended for 1 minute to form reinforced polypropylene. A resin composition was prepared. The subsequent treatment method (third step) was the same as above, except that in Comparative Example 2.4, a modified polypropylene resin was mixed in order to improve the reinforcing effect of the glass fibers.

Next, each example and comparative example will be explained using Table 1, Table 2, and FIG. 1.

"Examples 1 and 3. Comparative Examples 2 and 4" (Table 1 and Figure 1) In Example 1, crystalline polypropylene resin, ethylene-α
First granules obtained by melt-kneading an olefin copolymer, aromatic hydrocarbon resin, and talc, and 30% glass fiber in advance.
Mixed glass fiber reinforced polypropylene resin (hereinafter referred to as
The total composition contains 2.5% glass fiber.

In contrast to Comparative Example 2, in which glass fiber was directly added and all the raw materials were melt-kneaded at once, Example 1 had improved mechanical strength,
Improvement in heat resistance is observed.

Further, the vibration damping performance of Example 1 is approximately the same as that of Comparative Example 2, but is at a sufficiently higher level than Comparative Example 1 containing only talc. Furthermore, as a result, 5% glass fiber
Example 3 including: Regarding Comparative Example 4, the damping performance of Comparative Example 4 is slightly higher.

Example 3 is better in bending strength and heat resistance.

It turns out that it is better to use glass fiber in the form of glass fiber reinforced polypropylene resin.

"Example 2. Comparative Example 3" (Table 1) In Example 2, as described above, a crystalline polypropylene resin, a modified polypropylene resin, and glass fiber were melt-kneaded to produce a second granular body of PPG.

This material was mixed with the first granular material prepared separately, and the physical properties of the molded product were almost the same as in Example 1. On the other hand, in Comparative Example 3 in which the ethylene-α olefin copolymer and the aromatic hydrocarbon resin were mixed on the PPG second granule side as described above, the mechanical strength and heat resistance were significantly decreased.

From the above results, it is clear that the method of the present invention is to mix the first granules prepared by melt-kneading the ethylene-α olefin copolymer and the aromatic hydrocarbon resin together with the crystalline polypropylene resin and talc, and the second PPG granules. It can be seen that according to the manufacturing method, a molded product having excellent vibration damping performance 9 mechanical strength and heat resistance over a wide temperature range can be obtained.

Further, FIG. 1 illustrates the vibration damping performance and bending strength of the examples and comparative examples shown in Table 1 above. From the same figure 1
It can be seen that the height measurement according to the present invention has excellent vibration damping performance and bending strength.

"Examples 4 to 9. Comparative Example 1" (Table 2) Examples 4 to 9
are examples in which aromatic hydrocarbon resins with different softening temperatures were used (Example 4 was 80°C, Examples 5 to 9 were 120°C
) An example using talc with two different particle sizes (Example 5 is 2 μm)
, Examples 4, 6 to 9 are 8 μm), Examples where the glass fiber content in the total composition is 10% and 20% (Example 6 is 10%,
(Example 7 is 20%), an example where the ethylene-α olefin copolymer and aromatic hydrocarbon resin are mixed at a total of 21% (Example 8), and an example where the total amount of talc and glass fiber is 40% (Example 8). 9).

The results were good in all Examples.

It can be seen that according to the structural conditions of the present invention, a molded article having excellent vibration damping performance, mechanical strength, and heat resistance can be obtained.

"Example 10" Next, a gear cover molded using the reinforced polypropylene resin composition according to the present invention will be described.

The applied gear cover was for a 21 gasoline engine, and was injection molded using the compositions and processes of Example 2 and Comparative Example 1 at a cylinder temperature of 220 to 230°C and a mold temperature of 60°C. The size of this gear cover is 15C vertically!
1, width 30C11, depth 3cm, and thickness 0.25cm.

A bench test was conducted by assembling both gear covers to the engine under the same conditions, and a microphone was installed at a position 30 cm away from the gear cover to measure the sound pressure level. The temperature of the gear cover at the time of measurement was approximately 60°C. As a result, the gear cover for this example is as follows.

Approximately 1 to 1.5 dB (decibel) compared to that of Comparative Example 1
showed a noise reduction effect.

Furthermore, regarding the gear cover of Example 10.

No abnormalities were observed during long-term durability tests on a bench and actual vehicle driving tests.

From the above, it can be seen that according to the present invention, a reinforced polypropylene resin molded product having an excellent noise reduction effect and sufficient mechanical strength and heat resistance can be obtained.

[Brief explanation of the drawing]

The figure shows Examples 1 to 3. In Comparative Examples 1 to 3. It is a graph showing damping performance (loss tangent) and bending strength.

Claims (1)

[Scope of Claims] (A) 28.5 to 73% by weight of a crystalline polypropylene resin with a melt flow index of 5 to 50, (B) ethylene-α olefin copolymer (X) and aromatic hydrocarbon resin (Y) Consisting of (X): (Y)
Mixture B whose blending ratio [weight ratio] is 1:4 to 4:1.
2.5-28% by weight, (C) 15-45% by weight of talc with an average particle size of 1-20 μm
, a first step of mixing the three components and melt-kneading them to form a first granule; 50 to 95% by weight of the first granule obtained in the first step; (D) glass fiber reinforced polypropylene A second step of producing a reinforced polypropylene resin composition by mixing 5 to 50% by weight of the second granular material of the resin at 100° C. or below, and an injection molding machine for applying the reinforced polypropylene resin composition obtained in the second step a third step of molding the resin into a desired shape by, for example, the glass fiber-reinforced polypropylene resin containing 20 to 40% by weight of glass fiber, and the total amount of talc and glass fiber in the total composition. A method for producing a reinforced polypropylene resin molded product, characterized in that the content of the reinforced polypropylene resin molded product is 50% by weight or less.