WO2017170675A1

WO2017170675A1 - Resin composition production method

Info

Publication number: WO2017170675A1
Application number: PCT/JP2017/012871
Authority: WO
Inventors: 眞田　隆; 嶌野　光吉; 幸司亀尾
Original assignee: 住友化学株式会社
Priority date: 2016-03-31
Filing date: 2017-03-29
Publication date: 2017-10-05
Also published as: JPWO2017170675A1; JP6871914B2

Abstract

Provided is a method for producing a resin composition stably and with high productivity, in particular, a resin composition-producing method that melt-kneads a thermoplastic resin with a transition temperature of less than 200°C and a powder using a twin-screw kneading extruder, wherein: the powder is at least one kind of powder selected from a group consisting of inorganic fillers with an apparent density of 0.1-1.5 g/mL and thermoplastic resin powders with an apparent density of 0.1-1.0 g/mL and a transition temperature of at least 200°C; the thermoplastic resin with a transition temperature of less than 200°C is supplied to the twin-screw kneading extruder from a supply port; the powder is supplied to the twin-screw kneading extruder from a gravimetric feeder through a screw-type side feeder; the conveyance capacity of the screw-type side feeder is at least twice the effective volume of the powder per unit time; in the twin-screw kneading extruder, melt-kneading is performed under conditions in which the resin pressure in a first kneading zone is at least 1 MPa and the resin pressure in a second kneading zone is less than 5 MPa; and gas is removed from a vent port.

Description

Method for producing resin composition

The present invention relates to a method for producing a resin composition in which a thermoplastic resin and powder are melt-kneaded using a biaxial kneader.

A resin composition filled with a powder reinforcing material such as an inorganic filler gives a molded article having an excellent balance of required physical properties such as impact resistance, and is widely used as an industrial member typified by automobile parts. Also, a polymerized resin, such as polyphenylene ether or polyphenylene sulfide, which is powdery and bulky is compounded with a kneader and used in various applications because of its excellent characteristics.

When producing a resin composition by melting and kneading the thermoplastic resin powder or a powder raw material containing a large amount of powder reinforcing material using an extruder, the powder raw material is a pellet raw material. Since the apparent density is lower than that, the biting into the extruder is inferior. For this reason, the amount of extrusion achieved is small and productivity is often low.

The following are known as productivity improvement techniques of the method of melt-kneading powder raw materials.

For example, Patent Document 1 discloses a screw having a configuration in which a single screw having a wide flight width and a kneading disk having a specific twist angle are combined for the purpose of improving the productivity of a resin composition containing a filler component at a high concentration. A method for producing a resin composition using a twin screw extruder housed in a barrel is described.

Patent Document 2 discloses a resin using a twin-screw extruder provided with a screw having a combination of a single screw and a specific kneading disk for the purpose of improving productivity in the production of a resin composition using a powder raw material. A method for producing the composition is described.

In Patent Document 3, the material is included in the barrel downstream of the barrel to which the material supply port is connected for the purpose of increasing the extrusion amount at the time of extrusion molding of the fine powder raw material or the synthetic resin material containing a large amount of fine powder. An extrusion method in which a synthetic resin is melt-kneaded using a twin-screw extruder provided with an opening for discharging the air without providing a pressurizing region that gives strong compression between the material supply port and the opening. Are listed.

Patent Document 4 discloses a method for producing a resin composition containing a polypropylene resin and an inorganic filler by supplying a polypropylene resin and an inorganic filler from the upstream side of a twin-screw kneading extruder, and melt-kneading the product. For the purpose of improvement, a method is described in which the resin pressure in the plasticized region is 1 MPa or less.

In Patent Document 5, in the method for producing a resin composition containing a powdered polyphenylene ether and other thermoplastic resin, in order to improve the conveying ability of the powdered polyphenylene ether, the molten thermoplastic resin is transported in a region. A method of supplying powdery polyphenylene ether from the side of a twin screw extruder using a forced side feeder is described. In addition, in order to prevent a decrease in the conveying capacity of the powdered polyphenylene ether, an opening hole for venting gas is provided on the upstream side of the upper lid of the extruder barrel at the site where the forced side feeder is connected. Is preferably performed.

However, none of the above-described manufacturing methods has a sufficient productivity improvement effect.

Japanese Patent Laid-Open No. 9-29814 Japanese Patent Laid-Open No. 10-24483 JP 58-29644 A JP 2002-187125 A Japanese Unexamined Patent Publication No. 2011-255552

Under such circumstances, the object of the present invention is to stably produce a resin composition that gives a molded article having excellent impact resistance in a method for producing a resin composition in which a thermoplastic resin and powder are melt-kneaded. It is to provide a manufacturing method.

The present inventors have intensively studied and completed the present invention.

That is, the present invention is a method for producing a resin composition in which a thermoplastic resin having a transition temperature of less than 200 ° C. and powder are melt-kneaded using a biaxial kneading extruder,
The powder is a kind selected from the group consisting of an inorganic filler having an apparent density of 0.1 to 1.5 g / ml and a thermoplastic resin powder having an apparent density of 0.1 to 1.0 g / ml and a transition temperature of 200 ° C. or higher. Or more powder,
The biaxial kneading extruder includes, in order from the upstream, a supply port, a first kneading zone, a screw-type side feeder to which a weight type feeder is connected, a second kneading zone, and a vent port,
The thermoplastic resin having a transition temperature of less than 200 ° C. is supplied from the supply port to the biaxial kneading extruder,
The powder is supplied from the gravimetric feeder through the screw-type side feeder to the biaxial kneading extruder,
The conveying capacity of the screw-type side feeder is at least twice the effective volume per unit time of the powder supplied from the weight-type feeder to the screw-type side feeder,
The resin pressure in the first kneading zone is less than 1 MPa, and the melt pressure is kneaded under the condition that the resin pressure in the second kneading zone is less than 5 MPa,
The present invention relates to a method for producing a resin composition for removing gas from the vent port.

According to the present invention, it is possible to produce a resin composition that gives a molded article having excellent impact resistance by melting and kneading a thermoplastic resin and powder with high productivity.

In the present invention, the transition temperature of the thermoplastic resin is the melting peak temperature of the resin in the case of a crystalline thermoplastic resin, and the glass transition temperature of the resin in the case of an amorphous thermoplastic resin. It is determined by differential scanning calorimetry. More specifically, the melting peak temperature means a temperature corresponding to a melting peak of a crystal measured by differential scanning calorimetry according to JIS K7122 and observed in a range of −50 ° C. or higher and 200 ° C. or lower. The glass transition temperature means a glass transition temperature measured by differential scanning calorimetry according to JIS K7121.
Specific examples of thermoplastic resins having a transition temperature of less than 200 ° C. include polyolefin resins (high density polyethylene, low density polyethylene, polypropylene, etc.), cyclic olefin resins, aliphatic polyester resins (polylactic acid, etc.), fat Group polycarbonate, polyoxymethylene (polyacetal, etc.), styrene resin (polystyrene, SEBS, acrylonitrile-butadiene-styrene copolymer), etc., may be used alone or in combination with a plurality of resins. The shape may be pellets or powder. Furthermore, an olefin-based, styrene-based, acrylic-based, urethane-based, or engineering plastic-based elastomer may be added to improve impact strength and impart flexibility. Examples of the olefin elastomer include an ethylene-butene copolymer and an ethylene-octene copolymer. The transition temperature of the thermoplastic resin is preferably 190 ° C. or lower, preferably 0 ° C. or higher, and preferably 30 ° C. or higher. The state of the thermoplastic resin when it is supplied to the biaxial kneading extruder is not particularly limited, and for example, a pellet shape, a granule shape, a powder (powder) shape, or the like can be adopted.

In the present invention, the powder to be melt-kneaded with the thermoplastic resin having a transition temperature of less than 200 ° C. may be an inorganic filler having an apparent density of 0.1 to 1.5 g / ml. Natural silicates or natural silicates such as talc, kaolinite, clay, pyrophyllite, sericite, bentonite, silica, carbonates such as calcium carbonate, magnesium carbonate, hydrotalcite, aluminum hydroxide, magnesium hydroxide, etc. Hydroxide, zinc oxide, iron oxide, magnesium oxide, aluminum oxide, titanium oxide, mullite and other oxides, hydrous silicic acid, synthetic silicic acid such as anhydrous silicic acid or particulate filler such as mica, flakes such as mica Filler, basic magnesium sulfate whisker, calcium titanate whisker, chita Examples include potassium filler whiskers, aluminum borate whiskers, wollastonite, sepiolite, zeolite, attapulgite, zonotlite, rock wool, glass wool and other amorphous fillers such as carbon black, mesoporous carbon and activated carbon. . The apparent density of the inorganic filler is preferably from 0.1 to 1.0 g / ml, more preferably from 0.1 to 0.8 g / ml. Among the inorganic fillers having an apparent density of 0.1 to 1.5 g / ml, the inorganic filler having an (apparent density) / (true density) of 0.3 or less is more prominent in improving productivity by the production method of the present invention. It is preferable in that it can be seen. In the present application, the apparent density of a powder is an apparent density measured by the method of JIS K7365: 1999. The true density is a density calculated from the volume of the container excluding the gap portion when the container is filled with the powder. In this application, the true density of the powder is JIS Z8807: 2012. It refers to the density measured by the method.

In the present invention, the powder that is melt-kneaded together with the thermoplastic resin having a transition temperature of less than 200 ° C. may be a thermoplastic resin powder having an apparent density of 0.1 to 1.0 g / ml and a transition temperature of 200 ° C. or more. Specific examples of the thermoplastic resin powder include polyphenylene ether, polyphenylene sulfide, polyether ketone, polyamide resin (nylon 6, nylon 66, etc.), aromatic polyester resin (polyethylene terephthalate, polybutylene terephthalate, polybutylene). Naphthalate, etc.), aromatic polycarbonate, liquid crystalline polymer, and the like. Among these, the effects of the present invention are high, such as polyphenylene ether, polyphenylene sulfide, liquid crystalline polymer, etc., which have a high melting point and glass transition temperature, do not enter a melt flow state until a relatively high temperature, and maintain powder fluidity. It is done. The transition temperature of the thermoplastic resin constituting the thermoplastic resin powder is 200 ° C. or higher, preferably 210 ° C. or higher, preferably 450 ° C. or lower, more preferably 400 ° C. or lower.
When the total weight of the thermoplastic resin having the transition temperature of less than 200 ° C. and the powder is 100% by weight, the preferred range of the amount of the powder is 5 to 80% by weight, more preferably 10 to 70% by weight. %, More preferably 15 to 60% by weight.

The biaxial kneading extruder of the present invention includes a supply port, a first kneading zone, a screw-type side feeder to which a weight type feeder is connected, a second kneading zone, and a vent port in order from the upstream. The supply port is located in the most upstream part of the twin-screw kneading extruder. It is preferable that a weight type feeder is connected to the supply port.

The thermoplastic resin having a transition temperature of less than 200 ° C. is supplied from the supply port to the biaxial kneading extruder, and is kneaded in the first kneading zone under a condition that the resin pressure is less than 1 MPa. When a weight type feeder is connected to the supply port, a thermoplastic resin having a transition temperature of less than 200 ° C. is supplied from the weight type feeder to the twin-screw kneading extruder through the supply port.
The resin pressure in the first kneading zone (plasticization region) is preferably 0.8 MPa or less, more preferably 0.5 MPa or less. The resin pressure in the first kneading zone is usually 0.02 MPa or more, preferably 0.1 MPa or more.
The screw of the twin-screw kneading extruder according to the present invention is preferably a screw having two kneading segments from the viewpoint of increasing productivity. As a method of setting the resin pressure in the first kneading zone to less than 1 MPa, there is an effect of blocking the segment and the resin that pushes the resin back in the upstream direction by the rotation of the screw in the first kneading zone of the screw of the biaxial kneading extruder There are a method of not arranging a segment and a method of widening the clearance between the cylinder and the segment. As a segment that pushes the resin back in the upstream direction by the rotation of the screw, a reverse flight, a disk generally referred to as a reverse kneading disk whose twist angle exceeds 90 ° with respect to the feed direction (hereinafter referred to as “reverse disk”). For example). An example of the segment having an effect of blocking the resin is a seal ring. It is preferable to arrange only a so-called forward kneading disk (hereinafter referred to as “forward disk”) having a twist angle of less than 90 ° with respect to the feed direction in the first kneading zone of the screw. A so-called orthogonal disk having a twist angle of 90 ° can be further disposed in the first kneading zone of the screw as necessary. The position where the orthogonal disk is arranged is preferably on the downstream side of the above-mentioned forward disk. The pressure in each kneading zone of the twin-screw kneading extruder can be measured by installing a pressure sensor in each kneading zone of the cylinder and using the pressure sensor in each kneading zone.

A predetermined amount of powder is supplied from the weight-type feeder to the screw-type side feeder, and further supplied from the screw-type side feeder to the twin-screw kneading extruder. The conveying ability of the screw-type side feeder at this time is twice or more the effective volume per unit time of the powder supplied from the weight-type feeder to the screw-type side feeder. The conveying capacity of the screw-type side feeder is the volume per unit time of the powder supplied from the screw-type side feeder to the twin-screw kneading extruder, and this is the front while the screw of the screw-type side feeder rotates once. The product of the volume of space to be sent to the screw and the rotational speed of the screw, or the difference between the volume of the cylinder barrel per lead length of the screw of the screw-type side feeder and the volume of the screw per lead length of the screw-type side feeder, It can be determined as the product of the screw rotation speed of the feeder. The effective volume of the powder must be evaluated based on the volume actually supplied to the side feeder. The powder is weighed by a weight-type feeder connected to the upper part of the screw-type side feeder and supplied to the screw-type side feeder by natural fall. The effective volume per unit time of the powder supplied from the gravimetric feeder to the screw side feeder is the apparent density of the powder per unit time of the powder supplied from the gravimetric feeder to the screw side feeder. It is obtained as a value obtained by dividing. In this application, the apparent density of the powder used to calculate the effective volume is the same height as when the powder is actually supplied from the weight type feeder to the screw type side feeder. It is a value obtained by dropping and dividing the weight of the powder in the measuring container by the volume of the powder measured in the measuring container. The conveying capacity of the screw-type side feeder depends on the specifications of the apparatus, but is preferably at least twice the effective volume per unit time of the powder supplied from the weight-type feeder to the screw-type side feeder, more preferably 2. It is 4 times or more, preferably less than 8 times, more preferably less than 10 times.
Further, when the powder is supplied to the twin-screw kneading extruder using a screw-type side feeder, resin pellets or the like different from the powder may be supplied together with the powder. In this case, as long as the conveying capacity of the screw-type side feeder is sufficiently higher than the total amount of the effective volume of the powder supplied from the weight-type feeder to the screw-type side feeder and the volume of the resin pellets, the screw-type side feeder can be conveyed. It is not necessary to consider the volume of the resin pellet when setting the capacity. From the viewpoint of more stably supplying the powder to the twin-screw kneading extruder, the powder and the resin pellets of 25 parts by weight or more with respect to 100 parts by weight of the powder are passed through the screw type side feeder from the weight type feeder. It is preferably supplied to a shaft kneading extruder. The resin pellets supplied from the weight type feeder to the biaxial kneading extruder through the screw type side feeder are preferably 200 parts by weight or less with respect to 100 parts by weight of the powder. Examples of the resin pellet supplied from the weight type feeder to the twin-screw kneading extruder through the screw type side feeder include thermoplastic resin pellets having an (apparent density) / (true density) of 0.9 or more, and a transition temperature. There is no limit.

In the twin-screw kneading extruder applied to the present invention, a second kneading zone is provided on the downstream side of the position where the powder is fed by the side feeder, but the powder is fed to the twin-screw kneading extruder. A conveyance zone may be provided between the position and the second kneading zone. The resin pressure in the second kneading zone is set to less than 5 MPa, and the rate at which the gas mixed in the biaxial kneading extruder and the volatile components contained in the raw material escape to the downstream side of the biaxial kneading extruder with the powder supply is increased. , The amount of the gas or volatile component flowing back upstream is reduced. It is possible to set a resin pressure of less than 5 MPa by appropriately arranging, on the downstream side in the second kneading zone, a segment that pushes the resin back in the upstream direction by the rotation of the screw, or a segment that has an effect of blocking the resin. it can. From the viewpoint of sufficiently dispersing the powder supplied from the screw-type side feeder, the resin pressure in the second kneading zone is preferably 0.02 MPa or more, more preferably 0.1 MPa or more. The gap distance (chip clearance) from the stirring edge, which is the outermost peripheral end surface of the segment such as a reverse disk installed downstream of the second kneading zone, to the inner wall of the cylinder is equivalent to the gap distance from the flight top to the inner wall of the cylinder. However, in the present invention, in order to control the resin pressure in the second kneading zone as described above, the gap distance of the kneading disk used in the second kneading zone is two to three times the usual distance. Is preferably used. The normal gap distance varies depending on the manufacturer of the twin-screw kneading extruder, the cylinder diameter, the characteristics of the product to be produced, etc., but is generally about 0.2 to 1.5 mm. The thickness (disk width) of each kneading disk is usually about 1 / 5D (D is the screw diameter), but in the second kneading zone according to the present invention, 2 / 5D or more is preferable.

The biaxial kneading extruder applied to the present invention is provided with a vent port downstream from the second kneading zone, and removes the gas and volatile components out of the system. This vent (that is, removal to the outside of the system) may be a normal atmospheric release or a vent sucked under reduced pressure. The biaxial kneading extruder may further be provided with a third kneading zone downstream of the vent port. The resin pressure in the third kneading zone is preferably about 1 to 5 MPa.
Examples of the method of setting the resin pressure in the third kneading zone to about 1 to 5 MPa include a method of arranging a reverse disk and a seal ring on the downstream side in the third kneading zone, and a method of narrowing the clearance between the cylinder and the segment. It is done.

The biaxial kneader-extruder may be further provided with a vacuum vent port downstream from the third kneading zone. By providing a decompression vent port downstream of the third kneading zone, the gas and volatile components can be removed from the system more efficiently.

Next, the screw configuration of the twin-screw kneading extruder according to the present invention will be described. As the screw configuration of the first kneading zone, only a forward disk or, if necessary, an orthogonal disk or a reverse disk can be used in combination. If only a forward disk is used, the degree of fullness of the kneading zone is lowered, and the resin pressure in the first kneading zone is less than 1 MPa, so that the thermoplastic resin is transported downstream in a semi-molten state without being completely plasticized. can do. The resin pressure in the first kneading zone is preferably 0.01 MPa or more. From the viewpoint that the pressure can be increased to a desired pressure in a short section, it is preferable that the thickness of the disk is thinner in the first kneading zone. The gap distance (chip clearance) is preferably wider than usual. The purpose of the second kneading zone is to gradually knead the powder into the above-mentioned semi-molten resin while letting some volatile components escape to the vent port downstream from the second kneading zone. In addition, a wide disk is preferable which is mainly a forward disk. Further, it is preferable that the gap distance (chip clearance) is wider than usual. With respect to the third kneading zone, resin melting and dispersion of the powder in the molten resin have already been achieved to some extent by the second kneading zone. It can be set to about 5 MPa. It is preferable to use a full flight screw in a screw other than the kneading zone described here, that is, in a feed zone, a conveyance zone between the kneading unit and the kneading unit, a pressure increasing zone at the tip, and the like. Normally, two full flight screws are used. However, when it is desired to increase the transport volume, one full flight screw may be used.

Thus, when manufacturing a resin composition, another arbitrary component may be mix | blended according to the objective. Examples of such optional components include antioxidants, ultraviolet absorbers, light stabilizers, heat stabilizers, lubricants, antistatic agents, colorants, conductive agents, dispersants, printability-imparting agents, and organic fillings. Agents, flame retardants, flame retardant aids, foaming agents, processing aids, neutralizing agents, heavy metal deactivators, nucleating agents, antifogging agents, antibacterial agents, fungicides and the like.
These additives may be supplied together with the thermoplastic resin from the supply port in the first conveying zone of the biaxial kneading extruder into the biaxial kneading extruder, or in the second conveying zone or the third conveying zone. You may provide a supply port and it may supply in a twin-screw kneading extruder from there. The first transport zone is located between the most upstream supply port and the first kneading zone, the second transport zone is located between the first kneading zone and the second kneading zone, and the third transport zone Is located between the second kneading zone and the third kneading zone. A fourth transport zone may be further provided downstream of the third kneading zone.

According to the present invention, in the production of a resin composition in which powder having a low apparent density and a thermoplastic resin are melt-kneaded using a biaxial kneading extruder, the raw materials are not smoothly fed into the biaxial kneading extruder. In addition to enabling high-efficiency production without any trouble, it is possible to provide a method that can satisfy the conventionally required level in the physical properties of the resin composition such as dispersion of powder and elastomer and impact resistance. .

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

Measured values of each item in the examples were measured by the following methods.

(1) Izod impact strength (unit: kJ / m ² )
According to the method defined in JIS K7110, the Izod impact strength of the test piece produced by the following method was measured using an Izod impact tester manufactured by Toyo Seiki Seisakusho. The measurement was performed at a temperature of 23 ° C.
(Test piece preparation method)
Using a Sycap 110/50 type injection molding machine manufactured by Sumitomo Heavy Industries, Ltd., the resin composition pellets were molded at a molding temperature of 200 ° C., a mold cooling temperature of 30 ° C., an injection time of 15 seconds, a cooling time of 30 seconds, and a length of 64 × width 12 A molded body of a square bar having a thickness of 0.7 × 6.4 (mm) was injection molded. A V-shaped notch was processed in the thickness direction of the molded body to obtain a test piece.

As raw materials, polypropylene (transition temperature 160 ° C.) pellets, olefin elastomer pellets ethylene-butene copolymer pellets (transition temperature 38 ° C.) and ethylene-octene copolymer pellets (transition temperature 35 ° C.) Talc (apparent density 0.6 g / ml) was used as the powder. In addition, the apparent density of talc used to calculate the effective volume is dropped from a height of 2.3 m and received by the graduated cylinder in order to simulate the state of being fed from the weight type feeder to the screw type side feeder. It was obtained by measuring the weight per unit volume, and was 0.51 g / ml.

Example 1
As the biaxial kneading extruder, a twin-screw kneading extruder of the same direction meshing type with a cylinder diameter of 47 mm was used. The biaxial kneading and extruding machine has a cylinder and two screw shafts accommodated in the cylinder. From the upstream, the cylinder has a first conveyance zone, a first kneading zone, a second conveyance zone, a second It is divided into a kneading zone, a third transport zone, a third kneading zone, and a fourth transport zone. The cylinder was provided with a supply port at the uppermost stream in the first transfer zone, an open vent at the uppermost stream in the third transfer zone, and a vacuum vent at the uppermost stream in the fourth transfer zone. A biaxial screw-type side feeder was connected to the second transport zone of the cylinder, and a weight-type feeder was connected to the screw-type side feeder.
In the screw corresponding to the first kneading zone, only a forward (forward feed direction) disk was disposed so that the resin pressure in the first kneading zone was less than 1 MPa. The thickness of the forward disk was 0.2D (D is the screw diameter). In the screw corresponding to the second kneading zone, a forward disk was placed long from the upstream side, and finally a reverse disk was placed so that the resin pressure in the second kneading zone was less than 5 MPa. The thicknesses of the forward disk and the reverse disk were 0.5D, respectively. The air gap distance of these discs was twice the air gap distance of the flight. An open vent was provided downstream of the reverse disk in the second kneading zone.
For the screw corresponding to the third kneading zone, a forward disk, an orthogonal disk, and a reverse disk are arranged so that the resin pressure in the third kneading zone is 1 to 5 MPa, and the thickness of each disk is 0.1D. The thing of was used.
40 parts by weight of polypropylene pellets, 20 parts by weight of olefin-based elastomer pellets, and additives were fed into the twin-screw kneading extruder from the supply port at the most upstream part in the first transport zone of the twin-screw kneading extruder. 20 parts by weight of talc and 20 parts by weight of polypropylene pellets were supplied to a gravimetric feeder, fed from a gravimetric feeder to a biaxial screw side feeder, and fed from a biaxial screw side feeder into a biaxial kneading extruder. . The total feed amount of polypropylene pellets, olefinic elastomer pellets and talc fed into the twin-screw kneading extruder was 800 kg / hour. The effective volume of talc supplied from the weight type feeder to the biaxial screw type side feeder was 314 L / hour, and the conveying capacity of the screw type side feeder was 801 L / hour. The conveying capacity of the screw-type side feeder was about 2.5 times the volume per unit time of talc supplied from the weight-type feeder to the screw-type side feeder. The raw material is melt-kneaded at a screw rotational speed of 1350 rpm of a twin-screw kneading extruder and suctioned under reduced pressure from the vacuum vent, so that the raw material is smoothly fed into the twin-screw kneading extruder and stably polypropylene, olefin-based elastomer, Resin composition pellets containing additives and talc could be produced. At this time, the resin pressure in the first kneading zone was 0.1 MPa, the resin pressure in the second kneading zone was 0.4 MPa, and the resin pressure in the third kneading zone was 3.6 MPa.
The injection molded article made of the obtained resin composition pellets had an Izod impact strength of 58 kJ / m ² .

(Comparative Example 1)
The same twin-screw kneading extruder as in Example 1 was used. For the screw corresponding to the first kneading zone in Comparative Example 1, a forward disk and an orthogonal disk were used so that the resin pressure in the first kneading zone was 1 MPa or more. Arranged the reverse disk. Furthermore, the same procedure as in Example 1 was performed except that the total feed amount of polypropylene pellets, olefinic elastomer pellets and talc fed into the twin-screw kneading extruder was 900 kg / hour. The raw material was smoothly fed into the twin-screw kneading extruder, and the resin composition pellets could be produced stably. At this time, the resin pressure in the first kneading zone was 5.5 MPa, the resin pressure in the second kneading zone was 0.4 MPa, and the resin pressure in the third kneading zone was 2.4 MPa. An injection molded article using the obtained resin composition pellets had an Izod impact strength of 49 kJ / m ² .

(Comparative Example 2)
Using the same biaxial kneading extruder as in Example 1, the cylinder of the biaxial kneading extruder is provided with the first kneading zone of Comparative Example 2 slightly downstream from the second kneading zone of Example 1. The second kneading zone of Comparative Example 2 is provided at the same position as the third kneading zone of Example 1, an open vent is provided between the first kneading zone and the second kneading zone of Comparative Example 2, and the second kneading zone of Comparative Example 2 is provided. A vacuum vent was provided downstream of the two kneading zones. The zone upstream of the first kneading zone of Comparative Example 1 was the first transport zone of Comparative Example 1.
In the screw corresponding to the first kneading zone of Comparative Example 2, a forward disk is arranged long from the upstream so that the resin pressure in the first kneading zone is 0.2 to 3 MPa, and finally a reverse disk is arranged. did. For the screw corresponding to the second kneading zone of Comparative Example 2, a forward disk, an orthogonal disk, and a reverse disk were arranged so that the resin pressure in the second kneading zone was 1 to 4 MPa.
60 parts by weight of polypropylene pellets, 20 parts by weight of olefin-based elastomer pellets, 20 parts by weight of additives and talc are batched into the twin-screw kneading extruder from the most upstream supply port in the first conveying zone of the twin-screw kneading extruder. When the raw material is steadily fed into the twin-screw kneading extruder and the resin composition pellets containing polypropylene, olefinic elastomer, additive and talc are adjusted to the conditions that can be produced stably, the polypropylene pellets and olefinic The total feed amount of the elastomer pellets and talc was 450 kg / hour, and the screw rotation speed of the twin-screw kneading extruder was 1320 rpm. At this time, the resin pressure in the first kneading zone was 1.8 MPa, and the resin pressure in the second kneading zone was 1.6 MPa. The injection molded product using the obtained resin composition pellets had an Izod impact strength of 56 kJ / m ² .
When the screw rotation speed of the twin-screw kneading extruder was lowered to 1000 rpm, the raw materials were not smoothly fed into the twin-screw kneading extruder and production could not be continued.

When a resin composition is produced by melt-kneading using a twin-screw kneader / extruder, it is preferable that the resin composition can be stably melt-kneaded at an appropriate screw speed without applying excessive energy to the resin composition, and as many raw materials as possible Is more productive if it can be stably melt-kneaded at a low rotational speed. In Comparative Example 2, since the resin composition cannot be produced unless the total feed amount of the raw materials is less than that in Example 1, the productivity is low and the production stability is also poor.

Claims

A method for producing a resin composition in which a thermoplastic resin having a transition temperature of less than 200 ° C. and a powder are melt-kneaded using a biaxial kneading extruder,
The powder is a kind selected from the group consisting of an inorganic filler having an apparent density of 0.1 to 1.5 g / ml and a thermoplastic resin powder having an apparent density of 0.1 to 1.0 g / ml and a transition temperature of 200 ° C. or higher. Or more powder,
The biaxial kneading extruder includes, in order from the upstream, a supply port, a first kneading zone, a screw-type side feeder to which a weight type feeder is connected, a second kneading zone, and a vent port,
The thermoplastic resin having a transition temperature of less than 200 ° C. is supplied from the supply port to the biaxial kneading extruder,
The powder is supplied from the gravimetric feeder through the screw-type side feeder to the biaxial kneading extruder,
The conveying capacity of the screw-type side feeder is at least twice the effective volume per unit time of the powder supplied from the weight-type feeder to the screw-type side feeder,
The resin pressure in the first kneading zone is less than 1 MPa, and the melt pressure is kneaded under the condition that the resin pressure in the second kneading zone is less than 5 MPa,
A method for producing a resin composition, wherein gas is removed from the vent port.
The method for producing a resin composition according to claim 1, wherein the resin pressure in the second kneading zone is less than 3 MPa.
The method for producing a resin composition according to claim 1 or 2, wherein the biaxial kneader-extruder has the third kneading zone and a decompression vent port downstream from the third kneading zone further downstream of the vent port. .
The method for producing a resin composition according to claim 3, wherein the resin pressure in the third kneading zone is 1 MPa or more and less than 5 MPa.
The conveying capability of the screw-type side feeder is 2.4 times or more the effective volume per unit time of the powder supplied from the weight-type feeder to the screw-type side feeder. The manufacturing method of the resin composition as described in a term.
The powder and 25 parts by weight or more of resin pellets with respect to 100 parts by weight of the powder are supplied from the gravimetric feeder to the twin-screw kneading extruder through the screw-type side feeder. The manufacturing method of the resin composition as described in any one.
7. The powder according to claim 1, wherein the powder is one or more powders selected from the group consisting of talc, kaolinite, and clay, and the thermoplastic resin having a transition temperature of less than 200 ° C. is a polyolefin resin. A method for producing the resin composition according to claim 1.