JPH01263123A - Production of filled polyolefin molding material - Google Patents

Abstract

PURPOSE:To provide the subject material giving moldings having excellent mechanical strengths, by melt-kneading a polyolefin resin, an unsaturated carboxylic acid and a radical generator, adding an inorganic filler to the kneaded mixture at a specific kneading stage and further melt-kneading the mixture. CONSTITUTION:A mixture comprising (A) 100 pts.wt. of a polyolefin resin, (B) 0.01-10 pts.wt. of an unsaturated carboxylic acid (derivative) and (C) 0.001-1 pt.wt. of a radical generator (e.g., benzoyl peroxide) is first melt- kneaded. Before the grafting reaction of the component B to the component A is accomplished, (D) an inorganic filler (e.g., glass fibers) is mixed with the above-mentioned mixture in an amount of <=400 parts based on 100parts of the component A and further melt-kneaded to provide the objective material. The component B includes acrylic acid.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing a polyolefin molding material containing an inorganic filler, and more specifically, a molding material that has excellent mechanical strength and can be molded into inexpensive molded objects. Relating to a manufacturing method.

[Prior Art] Molding materials in which inorganic fillers are mixed with polyolefin resins such as polypropylene have been used. However, polyolefin resins have poor affinity with inorganic fillers, and the desired mechanical properties are 1! ? In many cases, this is not possible. Therefore, various methods have been used to improve the interfacial affinity between the inorganic filler and the polyolefin resin.

For example, there is a method of treating an inorganic filler with a coupling agent. This improves the interfacial affinity between the surface of the inorganic filler and the polyolefin resin.

In addition, polyolefin resin can be mixed with unsaturated carboxylic acid or unsaturated carboxylic acid Fl! It is also known that the use of a modified polyolefin modified with a 1 m conductor improves its affinity with inorganic fillers. For example, Japanese Unexamined Patent Publication No. 57-76041 discloses a composition in which a resin component is a mixture of a polypropylene resin and a modified polypropylene resin modified with an unsaturated carboxylic acid or a derivative thereof, and glass fibers. has been done. By using such a modified polypropylene resin, the interface surface W with glass RJ&M can be improved.
This improves strength, rigidity, heat resistance, etc.

By the way, a method of melt-kneading a filler into a modified polyolefin resin that has been modified in advance, such as a method of melt-kneading a modified polyolefin resin and an inorganic filler as described above;
There is a method of mixing and melt-kneading a polyolefin resin, an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative, a radical generator, and an inorganic filler.

[Problem to be Solved by the Invention j] As described above, when a modified polyolefin resin is used, the interfacial affinity with the inorganic filler is improved and the mechanical strength is improved. However, according to research conducted by the Ministry of the Invention, highly filled molding materials containing 100 parts by weight or more of inorganic filler per 100 parts of polyolefin resin,
It has become clear that even when produced by the method described above, the molded article cannot have the desired mechanical strength.

The present invention was made in view of these circumstances, and
The technical problem is to create a molding material that allows a molded article with excellent mechanical strength to be obtained by changing the mixing method of a modified polyolefin resin and an inorganic filler.

[Means for Solving the Problems] The method for producing a filler-containing polyolefin molding material of the present invention includes 100 parts by weight of a polyolefin resin, 0.01 to 10 parts by weight of an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative, and a radical. A first step of melt-kneading a mixture consisting of 0.001 to 1 part by weight of a generator, and the above-mentioned step before the completion of the grafting reaction of the unsaturated carboxylic acid or the unsaturated carboxylic acid derivative to the polyolefin resin in the first culm. It is characterized by performing a second step of remixing the inorganic filler in the mixture under a 400-weight suspension and then melt-kneading it.

As the polyolefin resin, polypropylene, polyethylene, a copolymer of polypropylene and polyethylene, a polypropylene copolymer obtained by copolymerizing polypropylene with other monomers, a polyethylene copolymer obtained by copolymerizing polyethylene with other monomers, etc. can be used.

Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid. In addition, as unsaturated carboxylic acid derivatives, 1. Acid anhydrides, esters, amides, gold B salts, etc. of saturated carboxylic acids can be used. Examples include maleic anhydride, citraconic anhydride, itaconic anhydride, ethyl acrylate, ethyl methacrylate, glycidyl acrylate, diethyl maleate, fumaric acid amide, and calcium acrylate.

This unsaturated carboxylic acid or unsaturated carboxylic acid derivative is o, oi based on 100 parts by weight of the above polyolefin resin.
It is blended so that it becomes 10 parts by weight. This prince is 0.0
When the amount is less than one overlapping part, the affinity with the inorganic filler decreases, and the mechanical strength of the obtained molded article decreases. 10 more
Even if it is blended in a larger amount than the weak and weak parts, the effect may be saturated and the water resistance of the resulting molded product may deteriorate.

As the radical generator, known peroxides can be used, such as benzoyl peroxide (BPO), dicumyl peroxide, and in some cases azobisisobutyronitrile (ΔrBN). This radical generator is o per 100 parts by weight of the polyolefin resin.
, ooi to 1 part. If this amount is less than 0°001711 parts, the modification of the polyolefin resin will be insufficient and the affinity with the ml-free filler will decrease. Also, if the amount exceeds 1 part by weight, the effect will be saturated,
Homopolymers of unsaturated carboxylic acids or unsaturated carboxylic acid y and s forms are easily synthesized, and molecular weight reduction due to molecular cleavage of polyolefin resins is severe.
The physical properties of the molded article may deteriorate.

The first step is a step of mixing and melt-kneading the above-described polyolefin resin, unsaturated carboxylic acid or unsaturated carboxylic acid derivative, and radical generator. In this first step, the unsaturated carboxylic acid or unsaturated carboxylic acid derivative is bonded to the polyolefin resin through a graft reaction.

The most important feature of the present invention is that, before the grafting reaction is completed, a second step of mixing an inorganic filler into the mixture and melt-kneading the mixture is performed. Here, before the grafting reaction is completed, in other words, it means before the radical generator is completely decomposed. For example, when using a radical generator with a half-life of t at the melt crosstalk temperature,
This means that it is before the time 6t to 7t for complete decomposition.

Inorganic fillers include glass fiber, mica, talc, clay, calcium carbonate, etc.
Quality fillers can be used.

In the present invention, this inorganic filler is mixed in an amount of 400 parts by weight or less with respect to 100 parts by weight of the polyolefin resin. If the amount of inorganic filler exceeds 400 parts by weight, the mechanical strength will decrease. The inorganic filler is preferably mixed in an amount of 100 IJ parts or more per 100 parts of the polyolefin resin. The effect of the present invention becomes remarkable,
This is because a molded article with excellent mechanical strength can be obtained at low cost.

Melt-kneading can be performed in a conventional manner. For example, it can be carried out by batch-wise charging a mixture of the formulations excluding the inorganic filler into a container, heating and melt-kneading, and then further mixing the inorganic filler into the mixture and melt-kneading before the grafting reaction is completed. can. It is also preferable to use an extruder as shown in FIG. For example, a mixture excluding inorganic fillers is charged into a hopper provided at the end of an extruder, and the mixture is melt-kneaded by rotation of a screw. Then, inorganic filler is mixed with the crosstalk from the middle of the cylinder,
Melt and knead roughly. This makes it possible to easily implement the present invention.

[Operations and Effects of the Invention] In the production method of the present invention, first, an unsaturated carboxylic acid or an unsaturated carboxylic M derivative is grafted onto a polyolefin resin in the absence of an inorganic filler. Then, before the Gelabt reaction is completed, an inorganic filler is mixed and further melt-kneaded. .

By doing so, a molding material can be obtained that allows the production of molded articles with excellent mechanical properties, although the mechanism thereof has not yet been elucidated.

Therefore, according to the production method of the present invention, a polyolefin resin, an unsaturated carboxylic acid or an unsaturated carboxylic w1 derivative,
The radical generator and the inorganic filler are all mixed and melt-kneaded, and the inorganic filler is mixed after the grafting reaction between the polyolefin resin and the unsaturated carboxylic acid or the unsaturated carboxylic S derivative is completed. A
Compared to the two methods of kneading, it is possible to produce a molding material that can be molded into a molded article having superior mechanical strength. Although the reason for this is not yet clear, it is presumed that a reaction occurs that increases the affinity between the resulting modified resin and the inorganic filler.

(Example] This will be explained in detail below using Examples.

(Example 1) FIG. 1 shows a schematic front view of a twin-screw pushing machine used in this example. This twin-screw pushing machine consists of a cylinder 1, a hopper 2 attached to the end of the cylinder 1, and a feeder 3 attached to the middle part of the cylinder 1. A screw 4.5 is arranged inside the cylinder 1 and the feeder 3. has been done. This twin-screw pushing machine has L/D=26.65 mmφ.

100 parts by weight of fintactic polypropylene with a melt flow rate of 1.4 g/10 min, maleic anhydride 0.5
The mixture and 0.1 parts of 1,3-bis-(t-butylberoxy-isobutyl)-benzene were mixed for 5 minutes in a Henschel mixer, and then fed to hopper 2 attached to a twin-screw pusher. Melt and knead.

Next, heavy calcium carbonate having an average particle size of 1.8 μm is fed into the cylinder 1 from the feeder 3 in a total amount of 12,711 parts. The material supplied from hopper 2 is 200℃
While moving to the position of the feeder 3, the mixture is melted and kneaded to cause a graft reaction. The time taken to reach the feeder 3 from the hopper 2 is about 30 seconds, and the graft reaction rate at the feeder 3 is about 75%.

And from the position of feeder 3! 11! Calcium carbonate is added and further melted and kneaded.

The mixed wire material extruded from the cylinder 1 was then formed into a pellet. This pellet was dried at 80℃ for 4 hours.
Test pieces for measuring mechanical strength were molded using an injection molding machine.

The flexural modulus, flexural strength, tensile strength, elongation, and notched isot of this test piece were measured and the results are shown in Table 1. In addition, the bending elastic modulus and bending strength are ASTM
Measured by D790, tensile strength and elongation are AST
Measured by MD638, notched isot is A
Measured by STM D256.

<Examples 2 to 4> Addition of maleic anhydride and radical generator. first hearing
A molding material was produced in the same manner as in Example 1 except for the changes shown in the table, and the mechanical strength of the test piece was measured. The results are shown in Table 1.

(Example 5) A molding material was produced in the same manner as in Example 1 except that 1 part by weight of maleic anhydride was used and the melt-kneading was performed at 250°C, and the mechanical strength of the test piece was measured.

The results are shown in Table 1.

(Examples 6 to 7) Examples except that a propylene-ethylene block copolymer with a melt flow rate of 10Q/10 minutes and an ethylene content of 7.4% was used instead of isotactic polypropylene in the formulation shown in Table 1. It is the same as 1. The results are shown in Table 1.

(Examples 8 to 10) Same as Example 1 except that fumaric acid, itaconic acid, and maleic acid were used as unsaturated carboxylic acids. The results are shown in Table 2.

(Comparative Examples 1 to 4) Using the same materials as in Example 1, with the formulation shown in Table 3,
The procedure was the same as in Example 1 except that Zl calcium carbonate was also supplied from hopper 2 at the same time and melted and kneaded. The results are shown in Table 3.

(Comparative Examples 5 to 8) 100 parts by weight of the same polypropylene as in Example 1, 20 parts by weight of maleic anhydride, and double-covered parts of benzoyl peroxide were placed in a 30-separable flask with an internal volume of 5 g and equipped with a stirring and reflux device. , and a small portion of xylene 600 were added, and the mixture was reacted in an oil bath at 140° C. for 4 hours. After the reaction is completed, excess At? The mixture was precipitated in a 100 ml solution, filtered, and dried to obtain maleic anhydride-modified polypropylene (hereinafter referred to as modified polypropylene). This modified polypropylene was grafted with 5.3% by weight of maleic anhydride.

Next, predetermined amounts of the polypropylene used in Example 1, the modified polypropylene, and the same calcium carbonate as in Example 1 were mixed for 5 minutes in a Henschel mixer, and all materials were fed from hopper 2 and melted and kneaded at 200°C. did.

Then, in the same manner as in Example 1, a pellet was formed, a test piece was molded, and the mechanical strength was measured. The results are shown in Table 4.

(Comparative Examples 9 to 12) Pellets of maleic anhydride-modified polypropylene were prepared by melt-kneading in the same manner as in Examples 1 and 4 except that calcium carbonate was not used. At this point, the reaction to the graph (graph) has been completed.Next, the same amount of calcium carbonate as in Example 1 was mixed with the pellets, and the molding material was produced by kneading with melt M at 200°C. The mechanical strength of the test piece was measured in the same manner as in Example 1. The results are shown in Table 5.

(Evaluation) As is clear from the table, according to the molded I material folded by the pA manufacturing method of the example of the present invention, the bending strength, tensile strength 1a,
It is clear that a molded article with significantly improved elongation and notched isot test results compared to those of Comparative Examples 1 to 12 is obtained. It is clear that this is because the φ-repurchased calcium oxide powder was added and melt-kneaded before the polypropylene grafting reaction was completed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram illustrating a schematic configuration of an extrusion type used in Examples. 1...Cylinder, 2...Hopper, 3...Feeder 4.5...Screw Patent applicant Toyoda Gosei Co., Ltd.

Claims (1)

[Claims] (1) A first step in which a mixture consisting of 100 parts by weight of a polyolefin resin, 0.01 to 10 parts by weight of an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative, and 0.001 to 1 part by weight of a radical generator is melt-kneaded. and, in the first step, before the grafting reaction of the unsaturated carboxylic acid or the unsaturated carboxylic acid derivative to the polyolefin resin is completed, an inorganic filler is mixed into the mixture in an amount of 400 parts by weight or less and further melted. A method for producing a filler-containing polyolefin molding material, the method comprising: a second step of kneading.