JPH02263867A - Production of thermoplastic resin composition and molded product therefrom - Google Patents

Abstract

PURPOSE:To obtain a fine granule-dispersed thermoplastic resin improved in quality and productivity by introducing a gas containing fine granules of specified size into a moving bed of the granular product of a thermoplastic resin in a unmelted state and by exhausting the gas while attaching or accumulating the fine granules to or on the moving bed. CONSTITUTION:A gas containing solid granules (e.g. titanium dioxide, calcium carbonate) <=10 (pref. <=1) mum in size is introduced into a moving bed of the granular product of a thermoplastic resin (e.g. polyethylene terephthalate) in a unmelted state, and the gas is exhausted while attaching or accumulating the fine granules to or on said moving bed. Thence, the resultant mixture of the granular product and fine granules is melted and kneaded, followed by carrying out molding. It is preferable that the fine granule concentration in the gas be 100-30000g/Nm<3> and the flow speed of the gas 10-40m/sec. The present process is especially effective when 5-40vol.% of such fine granules are to be incorporated.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a method for producing a functional composite material mixed with fine particles and molded into plastic products such as fibers, molded products, biaxially stretched films, etc. It provides:

(Conventional technology) Composite materials processed into molded products have traditionally been made of glass fiber,
Composites made by melting and kneading thermoplastic resins with fillers with a size of about 1 micron or more, such as carbon fibers and whiskers, are mainstream (for example, see Japanese Patent Application Laid-Open No. 61-277421). There is a problem with improving the impact resistance of products. On the other hand, when dispersing fine particles of titanium oxide, carbon black, magnetic materials, etc. with a size of about 1 micron or less, the mainstream method is to mix the fine particles during polymerization of thermoplastic resin and disperse them uniformly. Due to the high temperature of the system, the materials that are practically used are limited to fine particles with good heat resistance such as titanium oxide and carbon black, and in order to contaminate the polymerization equipment, special equipment is required and a large amount of cleaning is required. There are problems such as the need for labor and expense. A masterbatch method in which fine particles are kneaded at a high concentration is also well known, but it requires drying of the resin before kneading and drying of the masterbatch after kneading, which requires a large amount of energy and labor. Deterioration of the physical properties of molded products due to thermal history also poses a problem.

(Problems to be Solved by the Invention) Regarding the problem of molded products made from conventional composite materials, we have developed a composite material filled with submicron to micron-sized fine particles instead of the conventional filler of 10 to several tens of microns. There is a demand for technology to manufacture more advanced products, such as various molded products made from plastics, biaxially oriented films, sheets, and fibers made from composite materials that have never existed before. In other words, it is necessary to develop a new technology that integrates a powder process that handles submicron to micron-sized particles and a polymer process. Originally, powder processes and polymer processes are different technologies, and the creation of a technology that harmonizes them can be achieved by harmonizing pneumatic transport technology for submicron-sized particles and polymer processes. This requires a technology for collecting submicron particles that is compatible with polymer processes.

In general, in powder processes, dust collection using a bag filter is typical, for example, as an industrially implemented dust collection technique. However, it is not only difficult to achieve complete continuity as a powder process, but there are also problems such as moisture absorption and reaggregation of collected fine particles. For this reason, the problem to be solved by the present invention is to establish a new production technology that industrially and continuously collects submicron-sized particles and incorporates them into a polymer process.

(Means for solving the problem) As a dust collection technology for fine particles that can be incorporated into the polymer process, dust collection using a granular moving bed makes it possible to integrate the powder process and the polymer process, making it possible to solve this problem. became. That is, in the first aspect of the present invention, when melt-kneading a thermoplastic resin and fine particles, the particle size is 10 μm.
A gas containing fine particles of less than m in size is introduced into a particulate matter transfer layer of an unmolten thermoplastic resin, and the gas is discharged while the fine particles are attached or deposited on the particulate matter transfer layer, and the particulate matter and the fine particles are This is a method for producing a fine particle-dispersed thermoplastic resin composition, which is characterized by melting and kneading a mixture. A second aspect of the present invention is a method for producing a molded article, which comprises molding a fine particle-dispersed thermoplastic resin composition following the melting and kneading described above.

Thermoplastic resins used in the present invention include polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6, nylon 66, and nylon 12, polyolefins such as polyethylene and polypropylene, vinyl chloride, polycarbonate, polyurethane, and ABS resins. , and known thermoplastic resins such as copolymers and mixtures thereof.

The fine particles in the present invention are preferably 100° at room temperature.
It refers to solid particles having an average particle size of C or less and an average particle size of 10 μm or less, preferably 1 μm or less. For example, titanium oxide, calcium carbonate, silica, talc, lithopone, zinc oxide, mica,
Barium sulfate, alumina, kaolin, carbon black, tin oxide, glass peas, metal powders such as gold, silver, copper, iron, lead, aluminum, calcium silicate, zirconium oxide, zirconium carbide, antimony trioxide, bromine compounds, face wash For example, ``Practical Handbook of Additives for Plastics and Rubber J,'' edited by Kunio Goto, Aji Kagaku Kogyosha 1972.
The known additive particles described in the 2011 publication can be mentioned.

The amount of fine particles blended into the thermoplastic resin is usually 50% by volume or less based on the resin granules, but in the present invention it is 1 to 50% by volume.
It is effective when incorporated in a large amount in the range of 5 to 40 volume %, especially in the range of 5 to 40 volume %.

The fine particles contained in the gas are transported by gas to be introduced into the particulate transfer layer of the thermoplastic resin. A suction method, a low-pressure pumping method, and a high-pressure pumping method are used for gas transportation of fine particles. Properties of fine particles, mixing ratio of fine particles and gas (weight! 1 degree),
Depending on the airflow speed, transportation distance, etc., select gas source equipment such as Roots blowers, compressors, transportation pipes, solid/gas separation equipment, etc. as appropriate. Further, fine particles dispersed in a gas can be obtained by supplying the fine particles and gas to an ejector mechanism, for example, but airflow treatment using a jet mill or the like can yield airflow-dispersed fine particles with higher functionality. This is preferable because it can be pneumatically fed directly and continuously to the kneading process without being collected once. For example, there are methods in which drying and fine pulverization of a wet fine particle dispersion slurry are carried out simultaneously using a shared mill, methods in which classification or surface modification and pulverization are carried out simultaneously, and methods in which dry precise classification and pulverization are carried out simultaneously in a jet mill (special Kosho 56-40634, Kosho 55-
39370, 5B-898, 55-6433).

Gases used in the present invention include air, nitrogen, water vapor,
Examples include benzene and alcohol, and gases having a boiling point lower than the softening point of the thermoplastic resin are preferred. Further, it is preferable to use the gas by heating it to a temperature that does not melt or cool the thermoplastic resin, since the amount of gas used and the energy for heating the resin can be reduced.

The concentration of fine particles in the gas is usually 10 to 100,000 g/N
ra3, often 100-30000 g/Nm'. The transport velocity (flow velocity) of the gas containing fine particles is usually 5 to 100 m/sec, preferably 10 to 40 m/sec. If the transport speed is low, it is unfavorable in terms of re-agglomeration of particles and clogging of pipes, while if it is high, it is unfavorable in terms of wear of equipment and pipes. The pressure of the transport gas is usually -1,0 to 1.
0kg/c! 12 is used.

In the present invention, the granular material has a length of 0.1 to 1 in three directions.
It refers to granules or powder with a size of 0 mm, preferably 1 to 5 mm. The thermoplastic resin particulate transfer layer is obtained by a mechanism having the function of supplying, filling, and discharging thermoplastic resin particulates. For example, it can be easily obtained using a single-screw or two-wheel screw kneading extruder maintained below the melting point or softening point of the thermoplastic resin, or by a piping or static tubular mixing device equipped with a feeding and discharging mechanism for thermoplastic resin granules. You can also get When forming such a granular transfer layer of thermoplastic resin using a two-wheel screw kneading extruder, if the screw diameter is D, the residence time is 1 to 3 between 3 and 150 mm from the supply port of the resin granules. It is preferable to form it so that it has a length of about 10 minutes. If it is less than 2D, dust collection will not be sufficient, while if it exceeds 200, the dust collection effect will be saturated and the device will become long, which is not preferable.

The adhesion or accumulation of fine particles by the thermoplastic resin particle moving layer is due to the so-called inertial dust collection effect.In other words, when the fine particles gradually adhere to the surface of the resin granules, the fine particles adhere to each other and even cause bridging. , and a deposited layer of fine particles is formed in the resin granule layer. The filtration effect of this deposited fine particle layer is the key point of the present invention. This filtration effect depends on the gas flow rate, the moving speed of the resin particles, the particle size, properties, and specific gravity. In addition, pressure loss increases as fine particles accumulate, but in the present invention, the mixture of resin granules and fine particles is constantly moved and renewed in the direction of the subsequent process, so it is possible to keep the pressure loss almost constant. This enables efficient and stable collection of fine particles.

The gas from which the fine particles have been removed may be discharged either on the side where the thermoplastic resin granules are supplied or on the side where the melt-kneading process is carried out, but it is preferably carried out on the supply side. It can also be shared with the supply port (see Figure 3). It is also possible to suction and discharge by applying negative pressure with a blower or the like.

In the present invention, the mixture of thermoplastic resin granules and fine particles is melted and kneaded using, for example, a kneading extruder having a cylinder fitted with a screw or rotor (
Revised lithograph chemical engineering handbook p916-9, edited by the Chemical Engineering Society, Maruzen ■ Published in 1986, see). When the thermoplastic resin contains moisture or when it is desired to remove gas mixed in during melt-kneading, it is preferable to provide a vent and apply negative pressure or to degas it by nitrogen flow. Furthermore, in the case of polyester resins, nylon resins, polyethylene resins, etc. where the thermoplastic resin deteriorates or volatile substances are generated during melting and mixing, use screws equipped with two or more vents that rotate in the same or different directions. It is preferable to use a twin-screw kneading extruder having a devolatilization function that can be operated under high vacuum.

The melt-kneaded fine particle-dispersed resin composition is extruded from an outlet provided at the tip of a cylinder and guided directly to a die for obtaining fibers, sheets or films, or a mold for obtaining molded products, or by other known methods. Shaped by or -
It is first made into chips or powder and then subjected to molding.

Next, the present invention will be explained with reference to device diagrams.

In FIG. 1, 1 is a cylinder of a twin-screw kneading extruder. Two screws 2 rotating in the same direction are fitted into this cylinder 1. In the cylinder 1, a resin supply port A, a gas discharge port B, an inlet C1 for gas containing fine particles, and two vent holes Di and D2 are arranged in order at intervals in the longitudinal direction of the cylinder 1. The resin supply port A is located at the upstream end of the cylinder cylinder, and the downstream end is the outlet 3. Further, in the present invention, the melting start portion of the resin granules is located between the introduction port C and the vent hole D1. The screw 2 has a diameter of 65 mm, and the upstream side of the inlet C has a 15 mm deep groove 2a, the melting start part changes from the deep groove to the shallow depth 2d at the kneading desk, and the kneading part has a 4IIlffI shallow groove 2C.
Further, the vent hole provided in the kneading section has a slightly deep groove 2d of 6 mm. A heater (not shown) is attached to the cylinder. Also, the length of the deep groove portion 2a is 780 mm.
mm', the melting start part 2b is 195 mm, the shallow groove parts 2c and 2d including the vent part are 585 mm, and the distance between B and C is 585 mm.
It is mm.

A closed charging hopper for resin granules is attached to the resin supply port A via a chute. An intake blower is connected to the gas exhaust port B through a filter. A gas containing fine particles is injected into the inlet C from a gas compressor fine particle input device, a classification device, and an agglomerated particle crushing device.

For example, if a jet pulverizer described in JP-A-62-8215 is used, further surface treatment and drying can be carried out. A nitrogen flow device (not shown) is connected to the vent hole D1, and a vacuum pump (not shown) is connected to the vent hole D2.

Further, the cylinder outlet 3 is connected to a mouthpiece 6 having a slit hole through a gear pump 5, and the resin composition is extruded from the slit hole onto a rotating cooling drum and rapidly cooled to obtain a sheet. Next, this sheet is biaxially stretched to form a film, which is then heat-set, cooled, and rolled up.

In FIG. 2, 1 is a screw of a single screw extruder,
A resin supply port A, a gas inlet C5 containing fine particles, a gas exhaust port B, and a vent hole D are arranged in this order from the upstream side and spaced apart in the longitudinal direction. Further, in the present invention, the melting start portion of the resin granules is located between the exhaust port B and the vent hole D. The screw 2 has a diameter of 70 mm, and the upstream side from the exhaust port B has a 16 mm deep groove 2a, the melting start part gradually becomes a shallow groove 2b, the kneading part has a 4-hole shallow groove 2c, and the vent hole part has a 6III11 groove. There is a slightly deep groove 2d. A heater (not shown) is attached to the cylinder.

A closed charging hopper for resin particles is attached to the resin supply port A via a chute (not shown), and a gas exhaust port B is connected to the resin supply port A.
An intake blower is connected through a filter to
Gas containing fine particles is injected into the inlet C from a gas compressor, a fine particle feeding device, a classification device, and an aggregated particle crushing device, and a vacuum pump is connected to the vent hole D.

Further, the outlet 3 of the cylinder is connected to a spinneret 6' via a distribution pipe 4 and a gear pump 5, and the resin composition is extruded from the pores and wound up to obtain fibers.

FIG. 3 shows that, in FIG. 1, the fine particles are subjected to a pressure of 10 k
g/Cm'' of heated nitrogen is injected and then pulverized by colliding with a reversing orbit, and at the same time, it is pneumatically sent to the inlet C, and the gas is passed through the resin supply port A to the resin granules using, for example, a wire mesh filter. An example is shown in which the air is evacuated from a cloth-like bag after separation (see Japanese Unexamined Patent Publication No. 104642/1983).

Figure 4 shows resin granules at A and powdery resin granules at A.
’ and continuously fed with a screw feeder, 3
An example will be shown in which ~12 stationary mixing elements 8 are arranged to form a particulate matter moving layer. In addition, the gas exhaust port B is a biaxial deep groove part 2.
It can also be placed in a.

(Example) The present invention will be explained below using examples.

Example 1 IVO174 was installed in the resin supply port A of the twin-screw kneading extruder shown in Fig. 3.
, size 3.0mmφX3. 0 mmL of polyethylene terephthalate chips were supplied at 83 kg/hour, and the inlet C
Nitrogen containing anatase titanium oxide with an average particle size of 0.3 μm (concentration 1 kg/Nm,
temperature 210°C1 pressure 6kg/cm”) 17Nm3/
It was introduced at the time. The cylinder temperature was set to 210'C in the deep groove part, 280'C in the melting start part, 290'C in the kneading part and vent part.
After kneading at a reduced pressure of 3.6 Nm'/h nitrogen flow for Ventro DI and 5 Torr for Ventro D2, extrusion from a 290°C slit-type nozzle onto a rotating cooling drum was rapidly cooled and thickened. An amorphous sheet with a diameter of 1.1 mm was obtained.

Next, this sheet was stretched 3.0 times in the machine direction at 100°C, stretched 3.0 times in the cross direction at 110°C, and then
After heat setting at 00°C, the film was cooled and rolled up. The obtained film was 125 μm thick, white and opaque, and had an Iv of 0.61. Note that stretch forming could be performed continuously and stably.

The obtained film had a good white color with no coloration due to polymer decomposition by-products, and was extremely useful as a support for reflective photography.

Example 2 η1 = 2.7 in the resin supply port A of the uniaxial kneading extruder in Fig. 2
0 and size 2.0mmφX2. Omml of nylon 6 chips are supplied at a rate of 19.8 kg/hour, and the average particle size is 2 to the inlet B.
Nitrogen containing 0μm carbon black (50g/Nm”
A temperature of 180'C) was introduced at a rate of 4 Nm3/h. Cylinder temperature: 180°C at deep groove part, 250° at melting start part
C1 kneading section and vent section were set at 260°C, and ventro D was kneaded under reduced pressure of 10 Torr, then heated to 265'C.
The undrawn yarn is extruded from a spinneret and oiled to produce 1
It was wound up at a speed of 000 m/min. Next, this undrawn yarn was
A 208 denier/96 filament black spun-dyed nylon fiber was produced by double stretching. Note that the operations from kneading to stretching could be performed stably.

The obtained black spun-dyed nylon fiber had a strength of 3.4 g/d, an elongation of 40%, and uniform coloring.

Example 3 An average molecular weight of 8 was added to the resin supply port A of the twin screw kneading extruder in Figure 1.
0000 and size 3.0 φX3. OmmL polyethylene chips were fed at 80 kg/hour, and 0.75% by weight of antimony oxide was mixed with titanium oxide particles having a 15% by weight tin oxide film on the surface of the inlet C and fired. Air Y (concentration 500 g/Nm', temperature room temperature, pressure 10 kg) containing conductive fine particles with a particle size of 0.25 μm (hereinafter referred to as conductive particles X, specific resistance 6.3 Ω cm)
/cm2) at 4ONm'/hour (Unexamined Japanese Patent Publication No. 5
8=104642). Check cylinder temperature at deep groove part 50
'C, melting start part 230°C, kneading part and vent part 24
Set to 0'C, ventro Di, D2 to 10Tor
After kneading under reduced pressure to r, extrude to 3.0 m+nφX
3. It was molded into a chip Z2° of 0 mm L.

Next, the obtained chips z2° are supplied to the resin supply port A at a rate of 75 kg/hour, and the air Y containing the conductive particles X is supplied to the introduction port C.
was introduced at a rate of 5ONm'/hour and kneaded under the above conditions to form chips 2. . It was molded into.

Next, the chip z4° is supplied at a rate of 66.7 kg/hour, and air Y' containing conductive particles X (concentration 1000 g/Nm3,
(temperature: room temperature) was introduced at 33.3 Nm at 37 hours, and kneaded under the above conditions. It was molded into.

Next, chips Z6° were supplied at a rate of 62.5 kg/hour, air Y' containing conductive particles X was introduced at a rate of 37.5 Nm3/hour, and the mixture was kneaded under the above conditions to disperse conductive particles A chip ZIS of the polyethylene composition was molded.

Next, Chi, Tsubu Z? 5 as a conductive component,
Example 2 described in JP-A-60-224812
A conductive composite fiber was produced in the same manner as Y.

The operability of spinning and drawing was good, and the quality and conductivity of the obtained conductive composite fibers were also good.

Example 4 Kneading extruder shown in Fig. 4 (only the 2Ω portion has two screws and an inner diameter of 60M)
Polybutylene terephthalate chip (Mitsubishi Kasei ■Tsubadol 5) with a size of approximately 3 mmφ
010) at 65 kg/hour, size approximately 3ffIfllφ×
20kg of 3mmL styrene-butadiene block copolymer chips (Denka 5TR1602 from Denki Kagaku Kogyo)
At time Z, polystyrene bromide powder with an average particle size of about 0.1 mm (Nissan Ferro Organic Chemical ■ Pyrocheck 68PB) was added to A'.
Nitrogen containing antimony trioxide with a particle size of 0.3 μm (concentration 500 g/Nm3, temperature 15 kg/h)
0°C) was introduced at a rate of 1ONm3/hour, and the mixture was suctioned and discharged with a blower through a cloth filter. Set the static mixing element (inner diameter 80 cylinder, 6 elements, length 480 mm) and cylinder temperature to 150 °C for the two shaft parts, 1 kneading part 2b, 240 °C, vent 2d and measuring part 2c to 260 "C, 3. After kneading under reduced pressure to 10 Torr, extrusion was performed.
0mmφX3. It was made into an OmmL chip.

Various test pieces were then injection molded under normal conditions.

Injection molding could be performed stably. In addition to a high degree of flame retardancy, the test piece also had excellent impact resistance.

(Effects of the Invention) As explained in detail above, the present invention provides a new technique for producing thermoplastic resin compositions and molded articles in which fine particles of 10 μm or less, particularly submicron-level particles, are dispersed at a high concentration. It is. In other words, according to the present invention, it is possible to carry out the airflow treatment process of fine particles directly connected to the melt-kneading process and the molding process, thereby significantly improving quality, cost, and productivity, which were difficult to solve with conventional methods. be able to. The method of the present invention is also suitable for high-mix, low-volume production.
This provides an industrially extremely useful polymer process.

[Brief explanation of drawings]

Figures 1 to 4 are longitudinal cross-sectional schematic diagrams of equipment suitable for carrying out the method of the present invention. Figure 1 is a twin-screw kneading extruder, Figure 2 is a single-screw extruder, and Figure 3 is a resin feed port. FIG. 4 shows an example in which a particulate matter moving layer is formed in a stationary mixing element section.

Claims (1)

[Claims] 1. When melt-kneading a thermoplastic resin and fine particles, a gas containing fine particles with a particle size of 10 μm or less is introduced into a particle transfer layer of an unmolten thermoplastic resin to move the particles. A method for producing a fine particle-dispersed thermoplastic resin composition, which comprises discharging a gas while adhering or depositing fine particles in a layer, and melting and kneading a mixture of the fine particles and fine particles. 2. A method for producing a molded article, which comprises molding a fine particle-dispersed thermoplastic resin composition following the melting and kneading according to claim 1. 3. The method according to claim 1, wherein the gas is discharged closer to the part where the thermoplastic resin particles are provided than the part where the gas containing the fine particles is introduced.