JPH0730211B2 - Method for producing thermoplastic resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a thermoplastic resin composition. More specifically, the present invention relates to a method for producing a thermoplastic resin composition capable of producing a thermoplastic resin composition having a good appearance and excellent physical properties, which is always stable in quality.

[Prior Art and Problems] Conventionally, a thermoplastic resin composition in which a thermoplastic resin is reinforced with an ultrafine inorganic fiber having a high aspect ratio is not only high in rigidity but also reinforced with a glass fiber. It has already been known that the surface appearance is good and the strength is high as compared with the thermoplastic resin composition (JP-A-57-109846).

However, when kneading the inorganic fibers and solid thermoplastic resin such as pellets or powder in a kneader, the inorganic fibers are fragile because they are extremely fine, so they are broken, and the strength of the thermoplastic resin is high. However, there is a problem in that the effect of improving can not be sufficiently obtained.

On the other hand, as a method of not breaking the fragile inorganic fiber kneaded with the thermoplastic resin, there is a method generally used for kneading the glass fiber and the thermoplastic resin.

In the extruder having a separate and independent raw material supply port, the thermoplastic resin is first supplied to the raw material supply port (first supply port) located far from the extrusion port, and the thermoplastic resin is supplied in the extruder. By heating, the thermoplastic resin is brought into a molten state in the vicinity of the raw material supply port (second supply port) located near the extrusion port, and glass fiber is supplied from the second supply port to the thermoplastic resin in the molten state. This is a method of supplying and kneading the molten thermoplastic resin and the glass fiber in the extruder.

When the above method is used for kneading the inorganic fiber and the thermoplastic resin, the inorganic fiber is extremely fine and has a high aspect ratio, so that (1) the entanglement is strong and the entanglement is sufficient even when kneading. Since it cannot be loosened, it becomes impossible to produce the inorganic fiber immediately after it is clogged with the mesh of the extruder, or the surface appearance of the molded product is poor because it is not uniformly dispersed, resulting in poor performance of the molded product. (2) In this case, since the bulk specific gravity of the inorganic fiber is a small value of 0.1 or less, it is extremely bulky, so that the inorganic fiber cannot sufficiently bite into the kneader. However, there is a practical problem that only a small amount can be added to the molten thermoplastic resin.

Thus, in fact, in the method for producing a thermoplastic resin composition in which the thermoplastic resin is reinforced with the inorganic fiber, the production method capable of sufficiently exerting the effect of strengthening the thermoplastic resin with the inorganic fiber is There is a problem that it does not exist.

The present invention has been made based on the above circumstances.

That is, the object of the present invention is to produce a thermoplastic resin composition that can sufficiently exert the effect of strengthening the thermoplastic resin with inorganic fibers that are extremely fine and have a high aspect ratio, and that always has stable quality. It is intended to provide a method for producing a thermoplastic resin composition that can be manufactured.

[Means for Solving the Problems] The structure of the present invention for solving the problems has an average fiber diameter of 0.1 to 1.0 μm, an average aspect ratio of 50 to 300, and an oil absorption of 400 ml / 100 g. The average diameter obtained by granulating the inorganic fibers is 0.5 to 5 mm, and the granulated fibers having a bulk specific gravity of 0.15 to 0.4, and kneading the molten thermoplastic resin in a kneader And a method for producing a thermoplastic resin composition.

As the inorganic fiber in the present invention, fibrous magnesium oxysulfate, potassium titanate fiber, magnesium hydroxide fiber, magnesium oxide fiber, gypsum fiber,
Glass fiber, silicon carbide fiber, calcium silicate fiber,
Carbon fiber or the like can be used.

In particular, magnesium-based fibers such as fibrous magnesium oxysulfate, magnesium hydroxide fiber and magnesium oxide fiber are preferable.

In the present invention, the average fiber diameter of the inorganic fiber is 0.1
To 1.0 μm, preferably 0.2 to 0.8 μm
Is.

When the average fiber diameter is less than 0.1 μm, the inorganic fibers are easily broken and are broken, so that the effect of improving the strength of the thermoplastic resin cannot be sufficiently exerted, or the inorganic fibers are granulated. The fiber entanglement of the obtained granulated fiber becomes strong, the entanglement of the fiber cannot be sufficiently released, or the bulk specific gravity of the granulated fiber becomes too small, and the granulated fiber is sufficiently entangled in the kneader. There are times when it does not go well.

When the average fiber diameter exceeds 1.0 μm, the appearance of the molded product may be deteriorated due to the generation of gel in the molded product.

In the present invention, the aspect ratio of the inorganic fiber is 50
˜300, preferably 60 to 200.

If the aspect ratio is less than 50, the effect of improving the strength and rigidity of the thermoplastic resin may not be sufficiently exerted.

When the aspect ratio exceeds 300, the appearance of the molded product may be deteriorated due to the generation of gel in the molded product.

In the present invention, the oil absorption of the inorganic fiber is 400 ml / 10
It is 0 g or more, preferably 450 ml / 100 g.

When the oil absorption is less than 400 ml / 100 g, the entanglement of the granulated fibers becomes strong and the entanglement of the fibers cannot be sufficiently released.

In the present invention, a granulated fiber having a specific average diameter and bulk specific gravity obtained by granulating an inorganic fiber having a specific value with respect to the average fiber diameter, aspect ratio and oil absorption by an appropriate method is used.

As an appropriate method for granulation, for example, in a stirring tank containing a predetermined amount of water, the inorganic fibers are charged, crushed aggregates that are entanglement of the inorganic fibers under stirring, after separating the water, The crushed fiber in gel form has a system of 0.3-5 mm
There may be mentioned a method of producing a target granulated fiber by extruding from the hole to granulate and drying this in an oven.

In the present invention, the method for granulation is to stir the inorganic fibers in water to crush the aggregates, which is the entanglement of the fibers,
It is preferable to have a step of untangling the fibers.
In the case of a large amount of aggregates which are entanglement of inorganic fibers, the oil absorption of the inorganic fibers is less than 400 ml / 100g.

The average diameter of the granulated fiber is 0.3-5 mm, preferably
0.5 to 3 mm.

When the average diameter is less than 0.3 mm or more than 5 mm, the granulated fibers cannot be sufficiently bitten into the kneading machine, and it becomes difficult to produce a thermoplastic resin composition having stable quality.

The bulk specific gravity of the granulated fiber is 0.15 to 0.4, preferably 0.18 to 0.35.

When the bulk specific gravity is less than 0.15, the granulated fibers cannot be sufficiently bitten into the kneading machine, and it becomes difficult to produce a thermoplastic resin composition having stable quality.

When the bulk specific gravity is more than 0.4, the entanglement of the granulated fibers may not be sufficiently released, and the appearance of the molded product may deteriorate due to the generation of gel in the molded product.

The thermoplastic resin in the present invention is not particularly limited as long as it becomes plastic when melted and fluidized when heat is applied and solidifies when cooled, and examples thereof include polyethylene, polypropylene, polybutene, polyvinyl chloride and polystyrene. , Acrylic resin, ABS resin, nylon, polyacetal, polycarbonate, thermoplastic polyester and the like.

Polyolefins such as polyethylene, polypropylene and polybutene are particularly preferable. Furthermore, polypropylene is more preferable. The reason for this is that the inorganic fibers are uniformly dispersed in polypropylene, whereby more excellent mechanical properties can be exhibited.

Further, the thermoplastic resin may be any of a homopolymer, a copolymer and a mixture of two or more kinds of thermoplastic resins.

Further, the thermoplastic resin may be a blend of one or more of various elastomers, various inorganic fillers and various additives in the thermoplastic resin as long as the object of the present invention is not impaired. .

As the elastomer, for example, EP rubber, SB rubber or the like may be blended as desired.

As the inorganic filler, for example, talc, sericite,
Clay, carbon black, titanium oxide and the like may be added as desired.

Further, as the additives, a surface treatment agent, a dispersant, an antioxidant, an ultraviolet absorber, an antistatic agent, a weather resistance agent, a flame retardant and the like may be blended as desired.

What is important in the present invention is to knead the thermoplastic resin and the specific granulated fiber when the thermoplastic resin is in a molten state. In other words, the unmelted thermoplastic resin and the specific granulated fiber are simultaneously added to, for example, a kneader, and the thermoplastic resin is melted by heating to achieve the object of the present invention even when kneading. I can't.

When the thermoplastic resin is in a molten state, in order to knead the thermoplastic resin and the specific granulated fiber, a kneader, for example, an extruder, as a material supply port, is located far from the extrusion port. A material supply port (first material supply port) and a material supply port (second material supply port) located at a position close to the extrusion port are provided, and a thermoplastic resin is supplied from the first material supply port.
While the thermoplastic resin supplied from the material supply port is transferred in the extruder, the thermoplastic resin is heated to bring the thermoplastic resin into a molten state immediately below the second material supply port, and the thermoplastic resin is in this molten state. It is preferable that the specific granulated fiber supplied from the second material supply port is added to the thermoplastic resin to knead the thermoplastic resin in the molten state and the specific granulated fiber.

In order to carry out the kneading, the blending amount of the thermoplastic resin is 30 to 99% by weight, preferably 40 to 95% by weight, based on the total amount of the thermoplastic resin and the specific granulated fiber. In addition, it is preferable to feed the thermoplastic resin and the specific granulated fiber to a kneader such as an extruder. When the blending amount of the thermoplastic resin is less than 40% by weight, the impact resistance of the thermoplastic resin composition is significantly reduced, and the blending amount is 99% by weight.
When it exceeds, the rigidity of the thermoplastic resin composition is significantly reduced.

The kneading machine in the present invention is not particularly limited as long as it can knead the molten thermoplastic resin and the granulated fiber, for example, a single-screw extruder,
Screw extruder such as multi-screw extruder, elastic extruder, hydrodynamic extruder, ram type continuous extruder,
Examples include non-screw extruders such as roll type extruders and gear type extruders. Among these, in the present invention, a screw type extruder, particularly a twin screw extruder is preferable.

In the present invention, kneading is performed at a temperature equal to or higher than the melting temperature (or softening point) of the thermoplastic resin used.

When kneading with a screw extruder, the screw rotation speed is usually 100 to 600 rpm, and particularly preferably 200 to 300 rpm.

Thus, according to the method of the present invention, a thermoplastic resin composition is obtained in which the inorganic fibers blended as the specific granulated fibers are uniformly dispersed in the thermoplastic resin without breaking during kneading.

In addition, the method of the present invention has good production stability because the thermoplastic resin composition is always stably obtained.

The thermoplastic resin composition obtained by the method of the present invention has various molding methods such as an injection molding method, an extrusion molding method, a hollow molding method, a compression molding method, a lamination molding method, a roll processing method, a stretching processing method and a stamping method. It is molded into various molded products by the method.

The molded article of the thermoplastic resin composition obtained by the method of the present invention has a good surface appearance without generation of gel in the molded article and has excellent mechanical properties.

Therefore, the thermoplastic resin composition obtained by the method of the present invention is widely used as an automobile material or a weak electric material.

[Examples] Next, specific examples of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory view showing a kneading machine in an example of the present invention.

The granulated fibers used in the following examples and comparative examples were manufactured as follows.

Manufacture of granulated fiber A In 20 stirring tanks, water 10 and average fiber diameter of 0.6 μm, aspect ratio of 100, oil absorption of 510 ml / 100 g, and bulk specific gravity of
Add 1 kg of 0.06 fibrous magnesium oxysulfate (raw material), stir for 3 hours to disintegrate the aggregates, and then separate the water content.
It is extruded through a hole of m, granulated, and dried in an oven at 200 ° C. for 1 hour.
Got

Table 1 shows the properties of the fibrous magnesium oxysulfate and the properties of the granulated fiber after separation of water and before granulation.

Production of granulated fiber B In the production of the granulated fiber A, the average fiber diameter is 0.4 μm.
m, aspect ratio of 50, oil absorption of 380 ml / 100 g, and bulk specific gravity of 0.08, using fibrous oxysulfate (raw material), stirring time was changed from 3 hours to 10 minutes, and the fibers shown in Table 1 were used. In the same manner as in the case of the above granulated fiber A, except that granulated magnesium oxysulfate was used.
Granulated fiber B was produced.

Production of Granulated Fiber C In the production of the granulated fiber A, the average fiber diameter is 0.4 μm.
m, aspect ratio 40, oil absorption 320ml / 100g, and bulk specific gravity 0.09 fiber magnesium oxysulfate (raw material) is used, and water 2
Was added to form a gel, and the same fibrous magnesium oxysulfate shown in Table 1 was used to extrude and granulate in the same manner, and this was dried in an oven at 200 ° C for 1 hour to obtain the target granulated fiber. I got C.

The properties of the granulated fibers A, B and C are shown in Table 1.

In addition, in the following examples, the oil absorption was measured according to JIS-K5101 using the fiber before granulation as a sample.

Bulk specific gravity is measured by thoroughly drying the granulated fiber according to JIS-K51.
It was performed according to 01.

(Example 1) As a kneading machine, a twin-screw kneading machine 1 (TEM-35; manufactured by Toshiba Machine) shown in Fig. 1 was used.

Polypropylene a from the material supply port 2 in the biaxial kneader 1
(Ethylene content 4% by weight, MI = 8g / 10min) feed rate 2
The mixture was fed at 4 Kg / hour, the granulated fiber A was fed from the material feed port 3 at a feed rate of 6 Kg / hour, the kneading temperature was set to 200 ° C., and the rotor rotation speed was set to 500 rpm. The material supplied into the twin-screw kneader 1 flows in the direction of the arrow in FIG. 1, and the polypropylene a supplied from the material supply port 2
Is in a molten state at the position of the material supply port 3.

In this way, polypropylene a and granulated fiber A were kneaded to produce pellets by the strand cut method.

The presence or absence of breakage of the strand 4 extruded from the twin-screw kneader and the dispersed state of the fibrous magnesium oxysulfate in the produced pellet were visually observed to evaluate the production stability. In addition, the polypropylene a and the granulated fiber A are supplied from the material supply ports 2 and 3 according to the set conditions, and the strand 4 extruded from the biaxial kneader does not have a break or the like, and Since the fibrous magnesium oxysulfate was uniformly dispersed in the composition, it was evaluated that the production stability was good.

140 × 140 × 3m by injection molding machine using these pellets
A flat plate of m was created. It was observed whether gel was generated on the surface of the flat plate, and the surface condition of the flat plate was evaluated. Further, the bending strength (based on JIS K7203), the bending elastic modulus (based on JIS K7203), and the Izod impact strength (based on JIS K7110) were measured on the test pieces obtained from the flat plate.

The results are shown in Table 2.

(Example 2) The procedure of Example 1 was repeated, except that the supply rate of polypropylene a was 24 kg / hr and the supply rate of granulated fiber A was 6 kg / hr.

The results are shown in Table 2.

(Comparative Example 1) The same procedure as in Example 1 was performed except that the granulated fiber A was supplied from the same material supply port 2 as the material supply port that supplies the polypropylene a.

The results are shown in Table 2.

(Comparative Example 2) The procedure of Example 1 was repeated except that the granulated fiber B was used instead of the granulated fiber A.

The results are shown in Table 2.

(Comparative Example 3) The procedure of Example 1 was repeated except that the granulated fiber C was used instead of the granulated fiber A.

The results are shown in Table 2.

(Comparative Example 4) The same procedure as in Example 1 was carried out except that, instead of the granulated fiber A, an ungranulated fiber D (bulk specific gravity: 0.06) which was a raw material before granulating the granulated fiber A was used. However, probably because the bulk specific gravity was small, the ungranulated fiber D could not be manufactured because it was not well bitten into the kneading machine.

The results are shown in Table 2.

Further, the granulated fibers used in the following examples and comparative examples were manufactured as follows.

In the production of the granulated fiber A, the fibrous magnesium oxysulfate (raw material) having the average fiber diameter, the average aspect ratio, the oil absorption amount, and the bulk specific gravity shown in Table 3 is used, and the diameter of the extrusion hole is 3 mm. To 1mm, 2mm, 3mm, 0.4mm
Various granulated fibers E, F, G, and H were manufactured in the same manner as in the manufacture of the granulated fiber A, except that the granulated fiber A was changed to 8 mm.

Table 3 shows the properties of the granulated fibers E, F, G, and H.

(Example 3) The supply rate of the polypropylene a was set to 21 kg / hour, the granulated fiber E was used instead of the granulated fiber A, and the supply rate of the granulated fiber E was changed.
The same procedure as in Example 1 was carried out except that 9 Kg / hour was used.

The results are shown in Table 4.

(Example 4) The supply rate of the polypropylene a was set to 27 kg / hour, the granulated fiber F was used instead of the granulated fiber A, and the supply rate of the granulated fiber F was changed.
The same procedure as in Example 1 was carried out except that the rate was 3 Kg / hour.

The results are shown in Table 4.

(Comparative Example 5) The same operation as in Example 3 was performed except that the granulated fiber E was supplied from the same material supply port 2 as the material supply port that supplies the polypropylene a.

The results are shown in Table 4.

(Comparative Example 6) Example 3 except that the granulated fiber G was used in place of the granulated fiber E.
It carried out similarly to.

The results are shown in Table 4.

(Comparative Example 7) Example 3 except that the granulated fiber H was used in place of the granulated fiber F.
It carried out similarly to.

The results are shown in Table 4.

(Example 5) A supply rate of polypropylene a from the material supply port 2 is 21 kg /
Example 1 was repeated except that the talc was fed at a feed rate of 6 kg / hr and the granulated fiber A was fed from the material feed port 3 at a feed rate of 3 kg / hr.

The results are shown in Table 5.

(Comparative Example 8) The procedure of Example 5 was repeated, except that the granulated fiber A was supplied from the material supply port 2 instead of being supplied from the material supply port 3.

The results are shown in Table 5.

(Example 6) The same procedure as in Example 5 was carried out except that calcium carbonate (heavy calcium carbonate having an average particle diameter of 0.9 µ) was used instead of talc.

The results are shown in Table 5.

(Example 7) It carried out like Example 5 except having used ethylene propylene rubber (EPR) instead of talc.

The results are shown in Table 5.

(Example 8) Instead of polypropylene a, high density polyethylene (HDPE;
Example 1 was repeated except that the density of 0.968 g / cm ³ , MI = 5 g / 10 minutes) was used, and the granulated fiber F was used in place of the granulated fiber A.

The results are shown in Table 5.

(Example 9) Instead of polypropylene a, linear low-density polyethylene (LLDPE; butene-1 content 5 mol%, density 0.920 g / cm ³ ,
MI = 1.0 g / 10 min), and the same procedure as in Example 1 was carried out except that the granulated fiber F was used in place of the granulated fiber A.

The results are shown in Table 5.

(Example 10) The same procedure as in Example 1 was carried out except that an ABS resin (ABS; ABS resin HUHE1300 manufactured by Kanegafuchi Chemical Industry Co., Ltd.) was used instead of the polypropylene a.

The results are shown in Table 5.

[Effects of the Invention] In the case where a thermoplastic resin composition is reinforced by an inorganic fiber having an extremely fine and high aspect ratio to obtain a thermoplastic resin composition by the method for producing a thermoplastic resin composition of the present invention,
The effect of strengthening the thermoplastic resin with the inorganic fiber can be sufficiently exerted, and, compared with the conventional case, the performance of the thermoplastic resin composition for strengthening the thermoplastic resin with the inorganic fiber can be dramatically improved. You can

Furthermore, it is possible to always manufacture a thermoplastic resin composition having such excellent performance with stable quality.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a kneading machine in an example of the present invention. 1 ... Biaxial kneader, 2 ... Material supply port, 3 ... Material supply port, 4 ... Strand.

Claims (1)

[Claims] 1. An average fiber diameter of 0.1 to 1.0 μm, an average aspect ratio of 50 to 300, and an average diameter of 0.5 to 0.5 obtained by granulating an inorganic fiber having an oil absorption of 400 ml / 100 g or more. A method for producing a thermoplastic resin composition, which comprises kneading granulated fibers having a bulk specific gravity of 0.15 to 0.4 and a thermoplastic resin in a molten state in a kneader in a kneader.