JP3174152B2 - Manufacturing method of polypropylene injection molded product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an injection molded article having excellent impact strength and heat resistance rigidity.

[0002]

2. Description of the Related Art Conventionally, as a method for improving the impact strength of a polypropylene injection-molded product, there has been known a method using, for example, a polypropylene obtained by copolymerizing ethylene or butene-1 or a polypropylene mixed with a rubbery material as a raw material. ing.

On the other hand, as a method for improving the heat-resistant rigidity of a polypropylene injection-molded product, for example, a method using a polypropylene filled with fine powder particles such as talc or calcium carbonate as a raw material is known.

[0004]

However, an injection molded article molded from the above-mentioned polypropylene mixed with a copolymer or a rubber-like substance has an improved impact strength, but has a reduced heat resistance rigidity. There is a disadvantage that. Injection molded articles molded using polypropylene filled with fine powder particles have improved heat resistance rigidity, but have the disadvantage of reduced impact strength.

[0005] As described above, it has been difficult to obtain a polypropylene injection molded article excellent in both impact strength and heat resistance rigidity by a single means by the conventional method.

[0006]

Means for Solving the Problems The present inventor has conducted intensive studies on a method for improving the impact strength of a polypropylene injection-molded product by simple means, and as a result, has determined a cylinder in which a polypropylene containing a specific amount of γ-quinacridone is specified. The present inventors have found that injection molding at a temperature can provide a polypropylene injection molded product having both impact strength and heat-resistant rigidity, and completed the present invention.

According to the present invention, γ-quinacridone is used in an amount of 1 to 100.
Polypropylene containing in the range of 0 ppm, the cylinder temperature is in the range of the melting point to 350 ° C. for polypropylene,
In addition, the present invention provides a method for producing a polypropylene injection-molded article, wherein injection molding is performed under conditions satisfying the following formula.

(Equation 2) Here, Q is the content of γ-quinacridone (ppm) T is the cylinder temperature during injection molding

[0008]

[0009]

The polypropylene used in the present invention is not particularly limited as long as it is an isotactic polypropylene. For example, homopolypropylene, ethylene, butene-1
For example, random and block copolymerized polypropylene with other monomers can be used. Polymers other than polypropylene, fillers, crystal nucleating agents, antioxidants, heat stabilizers, lubricants, flame retardants, antistatic agents, pigments, and other additives as required, do not significantly impair the effects of the present invention. It may be contained in the range.

The content Q of γ-quinacridone in the polypropylene of the present invention is represented by the following formula:

[0012]

(Equation 3)

Although it is necessary to satisfy the relationship, it is generally 1 to 1,000 pmm, preferably 3 to 100 ppm. When the γ-quinacridone content is less than 1 ppm, the effect of improving the impact strength and heat stiffness is small, and when it exceeds 1,000 ppm, the effect of improving the impact strength is reduced, the red color is increased, and the cost is increased. It is not preferable because it becomes high.

The inclusion of γ-quinacridone in polypropylene can be carried out by any mixing method. For example, polypropylene powder or pellets and a predetermined amount of γ-
Mix quinacridone with a tumbler, Henschel mixer or the like. This mixture can be kneaded with a screw extruder or a roll.

The production of the polypropylene injection molded article in the present invention is carried out by using a usual screw in-line type or plunger type injection molding machine . Also, for example, low pressure injection molding, injection compression molding, gas injection injection molding, injection blow molding, push-pull injection molding, lost core injection molding,
It can also be performed by a special injection molding method such as shell injection molding.

At this time, in the present invention, the cylinder temperature T (° C.)

[0017]

(Equation 4)

Preferably, 0.007 <ΔQ / T <0.
It is extremely important to satisfy the above condition (1) in order to improve the impact strength and the heat-resistant rigidity of the target polypropylene injection molded article. That is, this

[0019]

(Equation 5)

When the value is less than 0.005, the impact strength of the obtained injection molded polypropylene article is not sufficient.
On the other hand, if it is larger than 0.2, the impact strength tends to exceed the peak and tends to decrease, and in general, the amount of γ-quinacridone added is increased, and as described above, the practicality is lost due to the problem of coloring. . In addition, the cylinder temperature T is the highest temperature in the cylinder temperature setting pattern, and in the case of a screw in-line type injection molding machine, it is usually the temperature of the metering portion. The cylinder temperature T is generally between the melting point of polypropylene and 350 ° C., preferably 200 ° C.
３００300 ° C.

[0021]

As will be understood from the above description, according to the present invention, a polypropylene injection molded article excellent in impact strength and heat resistance rigidity can be manufactured.

[0022]

EXAMPLES Examples of the present invention are shown below, but those present invention is not limited thereto.

[0023] The γ- quinacridone homo isotactic polypropylene powder PN130 manufactured by Tokuyama Soda Co., Ltd. were mixed amount shown in Table 1, in 40mmφ screw extruder 24
Melt kneading pelletizing was performed at 0 ° C. From the obtained pellets, using a screw in-line type injection molding machine , Table 1
Cylinder temperature, mold temperature 40 ° C, injection speed 1
An ASTM bending test piece and an Izod impact test piece with a notch were injection molded under the conditions of 3.5 cc / sec, injection pressure of 500 kg / cm ² , injection time of 30 seconds and cooling time of 10 seconds.

Table 1 shows the Izod impact strength and the heat distortion temperature measured at 23 ° C.

[0025]

[Table 1]

In Comparative Example 5, the test piece had a black-red color, which was not suitable for practical use. From the above,

[0027]

(Equation 6)

It can be seen that the polypropylene injection-molded article molded under the conditions of (1) is excellent in both impact strength and heat-resistant rigidity.

Claims (1)

(57) [Claims] 1. A polypropylene containing γ-quinacridone in the range of 1 to 1000 ppm, the cylinder temperature of which is :
A method for producing a polypropylene injection-molded article, wherein injection molding is performed in a range of from the melting point of polypropylene to 350 ° C. and under the following conditions. (Equation 1) Here, Q is the content of γ-quinacridone (ppm) T is the cylinder temperature during injection molding