WO2017179584A1

WO2017179584A1 - Method for manufacturing resin composition and biaxial kneading and extruding machine

Info

Publication number: WO2017179584A1
Application number: PCT/JP2017/014854
Authority: WO
Inventors: 眞田　隆; 幸司亀尾; 勇治福田; 嘉隆木村; 大吾佐賀
Original assignee: 住友化学株式会社; 株式会社日本製鋼所
Priority date: 2016-04-15
Filing date: 2017-04-11
Publication date: 2017-10-19
Also published as: JP2019104107A

Abstract

Provided is a novel method for manufacturing a resin composition in which thermoplastic resin and powder are melted and kneaded together, or the like. The manufacturing method of the present invention is a method for manufacturing a resin composition using a biaxial kneading and extruding machine. The biaxial kneading and extruding machine includes a cylinder (50) configured to include a first kneading zone (9), a second kneading zone (10), and a water-pouring and devolatilizing zone (15). The water-pouring and devolatilizing zone 15 includes a water-pouring and dispersing zone (13). The method includes a step of supplying water to the water-pouring and dispersing zone (13) and kneading and dispersing a resin composition to vaporize and remove a volatile component in the resin composition together with water.

Description

Method for producing resin composition and twin-screw kneading extruder

The present invention relates to a method for producing a resin composition and a twin-screw kneading extruder. More specifically, 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, and the resin composition is produced stably and with high productivity. In addition, the present invention relates to a method for reducing the amount of a volatile organic compound (Volatile Organic Compounds: abbreviated as VOC) remaining in a resin composition.

Thermoplastic resins such as polypropylene are relatively inexpensive, lightweight, and excellent in properties such as molding processability, mechanical properties, heat resistance, cold resistance, and long-term durability. Various containers, food packaging materials, and household goods It is used in a wide range of applications, such as textiles for carpets and sofas, interior and exterior materials for automobiles, materials for household appliances, and building materials such as interior materials for buildings or houses. In recent years, due to concerns about the problem of sick house (indoor air pollution), reduction of volatile organic compounds (VOC) has been demanded for resin materials used in various applications. VOC is one of the materials reported to be the causative agent of the sick house problem. The sick house problem is not only applied to building materials such as interior materials for buildings or houses, but also to interior materials for vehicles such as automobiles, and the use of resin materials with low VOC is desired.

As a method of reducing VOC in a thermoplastic resin, there is a method of drying and devolatilizing a thermoplastic resin which is a raw material before producing a resin composition by melt kneading, or drying and devolatilizing a resin composition after melt kneading. Although it is general, there are cases where it is not economical in view of the introduction of equipment such as a drying silo suitable for the production scale and the running cost for hot air or hot air drying. Also known is a method of reducing VOC by melt-kneading the resin composition produced by melt-kneading and water-injecting foam devolatilization again, but it is necessary to carry out melt-kneading twice. Therefore, it cannot be said to be an efficient method for producing a resin composition having a low VOC content.

The following is known as a technique for reducing VOC by performing water injection foam devolatilization.

For example, in Patent Document 1, a vacuum expansion zone is provided between the water injection dispersion zone and the devolatilization zone for the purpose of efficiently removing VOC from the molten resin, and between the vacuum expansion zone and the devolatilization zone, A water injection foaming devolatilization method in which a decompression ring having a slit is arranged is described.

Further, in Patent Document 2, in order to obtain a high screw rotation speed, water injection pressure, and water dispersibility for improving devolatilization efficiency, a seal ring is disposed only at one location downstream of the water injection dispersion zone. The water injection foam devolatilization method is described.

In Patent Document 3, even if the screw rotation speed is increased, the conveying screw of the devolatilization unit has a half-angle flight shape for the purpose of suppressing heat generation of the resin due to shear friction and extending the residence time of the resin. In addition, a conveying and kneading method is described in which gaps are formed on both sides of the flight so that a part of the resin flows backward from the downstream side to the upstream side.

Patent Document 4 improves the devolatilization efficiency by arranging a water injection dispersion zone consisting of a water dispersion foaming zone and a stirring zone for the purpose of speeding up the increase in the resin temperature near the bubble-resin interface in the water injection devolatilization step. The water injection devolatilization method is described.

Japanese Patent Publication “JP 7-164509 A (published on June 27, 1995)” Japanese Patent Publication “Japanese Patent Laid-Open No. 10-249913 (published on September 22, 1998)” Japanese Patent Publication “Japanese Patent Laid-Open No. 11-277604 (published on Oct. 12, 1999)” Japanese Patent Publication “JP 2002-326273 A (published on November 12, 2002)”

Since any of the above-described production methods has undergone a step of devolatilizing VOC after producing the resin composition, it takes extra time and cost, and as a method for reducing VOC in the resin composition, efficiency and economy From the viewpoint of

Under such circumstances, an object of the present invention is a method for producing a resin composition in which a thermoplastic resin and powder are melt-kneaded, and the resin composition is produced stably and with high productivity. An object of the present invention is to provide a method for reducing the amount of VOC remaining therein.

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

In order to solve the above problems, the present invention provides any of the following.
1) A method for producing a resin composition using a biaxial kneading extruder, wherein the resin composition contains a thermoplastic resin and powder as raw materials of the resin composition, and the biaxial The kneading extruder includes a cylinder, a screw-type side feeder connected to the cylinder, a weight-type feeder connected to the screw-type side feeder, and a screw installed in the cylinder. The cylinder includes a supply port, a connection port of the screw-type side feeder, a first vent port, a water injection port, and a second vent port in order from the upstream side of the cylinder. And the screw includes a first kneading zone located between the supply port and the connection port of the screw-type side feeder, and the screw-type side-feed. Comprising a second kneading zone located between the connection port of the feeder and the first vent port, and a water injection devolatilization zone located downstream of the first vent port, the water injection devolatilization zone Is composed of, in order from the upstream of the cylinder, a full pressure increase zone, a water injection dispersion zone where the water injection port is located, and a vacuum expansion zone where the second vent port is located. Supplying the powder from the supply port into the cylinder and supplying the powder from the gravimetric feeder through the screw-type side feeder into the cylinder, and the resin pressure in the first kneading zone is 0. A melt-kneading step of producing a resin composition containing the thermoplastic resin and powder by melt-kneading under a condition of 1 MPa or more and a resin pressure in the second kneading zone of less than 5 MPa; Kneading dispersion in which water is supplied from the water injection port to the water injection dispersion zone and the resin composition is kneaded and dispersed to vaporize volatile components in the resin composition together with water and remove from the second vent port. The thermoplastic resin has a transition temperature of less than 200 ° C., and the powder comprises an inorganic filler having an apparent density of 0.1 to 1.5 g / ml and an apparent density of 0.1 to 1.0 g / ml and one or more kinds of powder selected from the group consisting of thermoplastic resin powders having a transition temperature of 200 ° C. or higher, and the conveying ability of the screw-type side feeder is from the weight-type feeder to the screw-type The effective volume per unit time of the powder supplied to the side feeder is 1.2 times or more. In the kneading and dispersing step, the amount of water supplied to the water injection dispersion zone is Less than 5 parts by weight or more 0.1 parts by weight based on the total feed weight of the raw material into the Nda, resin pressure in the water injection dispersion zone is 1MPa or more, the production method.
2) A biaxial kneading extruder used for producing a resin composition containing a thermoplastic resin and powder as raw materials, a cylinder, and a screw-type side feeder connected to the cylinder A weight-type feeder connected to the screw-type side feeder, and a screw installed in the cylinder, and the cylinder in order from the upstream of the cylinder, the thermoplastic resin in the cylinder A supply port for supplying to the cylinder, a connection port of the screw-type side feeder for connecting the screw-type side feeder for supplying the powder into the cylinder, and a gas or a volatile component in the cylinder. A first vent port for removal outside the cylinder, a water injection port for supplying water to the resin composition, A second vent port for vaporizing the volatile component in the resin composition together with the water and devolatilizing, and the inside of the cylinder and the screw are connected to the supply port and the screw-type side feeder. A first kneading zone located between the mouth, a second kneading zone located between the connection port of the screw-type side feeder and the first vent port, and water injection located downstream of the first vent port. A twin-screw kneading extruder comprising a devolatilization zone.

According to the present invention, a resin composition can be produced stably with high productivity, and the amount of VOC remaining in the resin composition can be reduced.

It is a figure which shows schematic structure of the twin-screw kneading extruder which concerns on one Embodiment of this invention.

First, the resin composition produced by the production method of the present invention and the raw material of the resin composition will be described below.

The resin composition targeted for the production of the present invention is a resin composition containing a powdered resin reinforcing material. The resin composition obtained by the production method of the present invention may be provided as a resin compound product having a pellet shape or the like. The resin composition obtained by the production according to the present invention is widely used as an industrial member such as an automobile part, and specifically, is used for an interior material of an automobile.

(Thermoplastic resin)
The thermoplastic resin used as a raw material of the resin composition according to the present invention is a thermoplastic resin having a transition temperature of less than 200 ° C. Here, 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. The temperature can also be determined by differential scanning calorimetry.

Specific examples of thermoplastic resins include polyolefin resins (high density polyethylene, low density polyethylene, polypropylene, etc.), cyclic olefin resins, aliphatic polyester resins (polylactic acid, etc.), aliphatic polycarbonates, poly Examples include oxymethylene and styrene resins. Specific examples of polyoxymethylene include polyacetal and the like, and examples of styrene resins include polystyrene, SEBS (styrene / ethylene / butylene / styrene block copolymer), and acrylonitrile / butadiene / styrene copolymer. Etc. These may be used alone or in combination with a plurality of resins. The shape supplied to this manufacturing method may be a pellet or a powder (powder).

(powder)
The powder that can be used as a raw material for the resin composition of the present invention includes an inorganic filler having an apparent density of 0.1 to 1.5 g / ml, an apparent density of 0.1 to 1.0 g / ml, and a transition temperature of 200 ° C. It is selected from the group consisting of the above thermoplastic resin powders (hereinafter sometimes simply referred to as “thermoplastic resin powder”). Only one type of powder may be used, or a plurality of types may be used.

In the present specification, “˜” indicating a numerical range indicates a numerical range including the lower limit and the upper limit (that is, above and below) unless otherwise specified.

<Inorganic filler>
Specific examples of the inorganic filler having the above-described conditions include natural silicic acid or silicate, carbonate, hydroxide, oxide, particulate filler, flaky filler, fibrous filler, and carbon. Can be mentioned. Furthermore, examples of natural silicic acid or silicate include talc, kaolinite, clay, pyrophyllite, sericite, bentonite and silica. Examples of carbonates include calbium carbonate, magnesium carbonate, hydrotalcite and the like. Examples of the hydroxide include aluminum hydroxide and magnesium hydroxide. Examples of the oxide include zinc white, iron oxide, magnesium oxide, aluminum oxide, titanium oxide and mullite. Examples of the particulate filler include a synthetic filler such as hydrous silicate or anhydrous silicate, or a particulate filler such as silicate. Further, examples of the flaky filler include mica, and examples of the fibrous filler include basic magnesium sulfate whisker, calcium titanate whisker, potassium titanate whisker, aluminum borate whisker, and wollastonite. , Sepiolite, zeolite, attapulgite, zonotlite, rock wool, glass wool, glass fiber and carbon fiber.

The apparent density of the inorganic filler is 0.1 to 1.5 g / ml, preferably 0.1 to 1.0 g / ml, more preferably 0.1 to 0.8 g / ml.

Here, the apparent density means a density expressed by weight per unit volume, and in this application, the apparent density of the powder indicates an apparent density measured by the method of JIS K7365: 1999.

Further, among the inorganic fillers having an apparent density of 0.1 to 1.5 g / ml, (apparent density) / (true density) is preferably 0.3 or less, more preferably 0.25 or less, and still more preferably 0.00. Those that are 2 or less are used. For example, 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 has an effect of improving productivity by the production method of the present invention. It is preferable in that it is more noticeable.

Here, 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, and in this application the true density of the powder is JIS Z8807. : The density measured by the method of 2012 is pointed out.

<Thermoplastic resin powder>
The thermoplastic resin powder that can be used as a raw material for the resin composition of the present invention is 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. Specific examples of the thermoplastic resin powder include polyphenylene ether, polyphenylene sulfide, polyether ketone, polyamide resins (such as nylon 6 and nylon 66), and aromatic polyester resins (polyethylene terephthalate, polybutylene terephthalate, polybutylene). Naphthalate, etc.), aromatic polycarbonate, liquid crystal polymer and the like. Among them, the effects of the present invention are particularly high, such as polyphenylene ether, polyphenylene sulfide, and liquid crystallinity, which have a high melting point and glass transition temperature, do not enter a melt-flow state up to a relatively high temperature, and maintain powder fluidity. Examples thereof include polymers.

In the production method of the present invention, in order to produce the resin composition, the ratio of the raw materials supplied to the biaxial kneading extruder described later is the total weight of the thermoplastic resin having a transition temperature of less than 200 ° C. and the powder. The preferred range of the powder is 5 to 80% by weight, more preferably 10 to 70% by weight, still more preferably 15 to 60% by weight.

(Optional component)
In the resin composition to be produced according to the present invention, other optional components may be blended in addition to the above-described components. Examples of such optional components include elastomers, and more specifically, olefin-based, styrene-based, acrylic-based, urethane-based or engineering plastic (engineering plastic) -based elastomers. Examples of the olefin elastomer include ethylene-α-olefin copolymers such as an ethylene-propylene copolymer, an ethylene-butene copolymer, and an ethylene-octene copolymer. Also, antioxidants, UV absorbers, light stabilizers, heat stabilizers, lubricants, antistatic agents, colorants, conductive agents, dispersants, printability imparting agents, organic fillers, flame retardants, flame retardant aids And additives such as an agent, a foaming agent, a processing aid, a neutralizing agent, a heavy metal deactivator, a nucleating agent, an antifogging agent, an antibacterial agent, and an antifungal agent.

If an elastomer is added in addition to the thermoplastic resin, the impact strength of the produced resin composition can be improved or flexibility can be imparted.

In the production method of the present invention, in order to produce a resin composition, as a ratio of raw materials supplied to a biaxial kneading extruder described later, when the total weight of all raw materials of the composition is 100 parts by weight, A preferable range of the thermoplastic resin having a transition temperature of less than 200 ° C. is 20 to 95 parts by weight, more preferably 30 to 90 parts by weight, and still more preferably 40 to 85 parts by weight. The preferred range of the powder is 5 to 80 parts by weight, more preferably 10 to 70 parts by weight, and still more preferably 15 to 60 parts by weight.

Further, in addition to the above-described thermoplastic resin having a transition temperature of less than 200 ° C. and thermoplastic resin powder having a transition temperature of 200 ° C. or more, resin pellets may be further used as a raw material. For example, thermoplastic resin pellets having an (apparent density) / (true density) of 0.9 or more can be mentioned. Moreover, the transition temperature of the resin pellet is arbitrary. Moreover, when the resin pellet is a resin pellet containing a thermoplastic resin of less than 200 ° C., the ratio of the supply amount of the resin pellet in the raw material includes the thermoplastic resin having a transition temperature of less than 200 ° C. and the resin pellet. The total supply amount with the thermoplastic resin of less than 200 ° C. is calculated as the supply amount of the thermoplastic resin having a transition temperature of less than 200 ° C. as the raw material of the resin composition according to the present invention.

(Specific example of combination of raw materials for thermoplastic resin composition)
In one embodiment, the powder as a raw material of the resin composition is at least one powder selected from the group consisting of talc, kaolinite and clay, and the thermoplastic resin having a transition temperature of less than 200 ° C. Polyolefin resin.

[1. Method for producing resin composition]
The present invention is a method for producing the above-described resin composition. More specifically, the present invention relates to a method for producing a resin composition using a biaxial kneading extruder having a predetermined structure, which will be described later. 1) Biaxial kneading extrusion of raw materials (thermoplastic resin or powder) 2) a supply process for supplying into the cylinder of the machine, 2) a melt-kneading process for melting and kneading the raw material supplied into the cylinder to produce a resin composition, and 3) water for the resin composition produced in the melt-kneading process. A kneading and dispersing step of supplying and kneading and dispersing. These steps are a series of processes in which a raw material is continuously or intermittently supplied to a cylinder of a twin-screw kneading extruder to produce a resin composition, and the produced resin composition is continuously extruded from the cylinder. In parallel.

The method according to the present invention can be carried out using, for example, a twin-screw kneading extruder 100 shown in FIG. FIG. 1 is a diagram showing a schematic configuration of an exemplary apparatus for carrying out a manufacturing method according to the present invention.

(Biaxial kneading extruder 100)
As shown in FIG. 1, the twin-screw kneading extruder 100 includes a cylinder 50, a screw-type side feeder 2 connected to the cylinder 50, a weight-type feeder 3 connected to the screw-type side feeder 2, And a screw 30 installed in the cylinder 50. The cylinder 50 includes a supply port 1, a connection port for the screw-type side feeder 2, a first vent port 4, a water injection port 5, and a second vent port 6 in order from the upstream side of the cylinder. The inside of the cylinder 50 and the screw 30 include a first kneading zone 9 located between the supply port 1 and the connection port of the screw-type side feeder 2, and a connection port of the screw-type side feeder 2 and the first vent port 4. A second kneading zone 10 located in between and a water injection and devolatilization zone 15 located downstream of the first vent port 4 are configured. The water injection devolatilization zone 15 includes a third kneading zone 11 and a decompression / expansion zone 14 in order from the upstream side, and the third kneading zone 11 further includes a full pressure increase zone 12 and a water injection side in order from the upstream side. The dispersion zone 13 is included. The water injection port 5 is provided so as to open to the water injection dispersion zone 13, and the second vent port 6 is provided so as to open to the reduced pressure expansion zone 14.

In addition, the inside of the cylinder 50 and the screw 30 upstream of the first kneading zone 9 is a first transport zone, and the transport zone between the first kneading zone 9 and the second kneading zone 10 is a second transport zone. . Further, a conveyance zone between the second kneading zone 10 and the third kneading zone 11 is defined as a third conveyance zone. Moreover, the water injection devolatilization zone 15 is also a 4th conveyance zone. Although not shown in the drawing, the fourth transport zone may be from the water injection devolatilization zone 15 to a transport zone further provided downstream of the water injection devolatilization zone 15.

In the following items, the details of the manufacturing method and operation according to the present invention will be described separately for each step that is continuously performed in parallel with reference to FIG. About each structure of the twin-screw kneading extruder of this invention, a detail is demonstrated with the detail of each process.

In this specification, when describing the positional relationship between the two configurations in the vertical direction, for example, the expressions “upper” and “lower” are used, and each configuration is positioned in contact with or apart from each other. means. Moreover, in this specification, the direction of the arrow shown in the lower part of FIG. 1 means the flow direction when the resin material is transferred in the apparatus, and there are a certain part of the apparatus and other parts. Or the positional relationship at a certain point in one member of the apparatus, it is referred to as “upstream” and “downstream” or “upstream” and “downstream” with respect to the flow direction of the resin material. Use expressions. Further, the most upstream and downstream end faces in one member are expressed as “upstream end” and “downstream end”, respectively.

(Supply process)
This step is a step of supplying the raw material into the cylinder 50. Specifically, the thermoplastic resin supplying step of supplying the above-described thermoplastic resin into the cylinder 50 continuously or intermittently, and the thermoplastic resin Is a step of performing the powder supply step in parallel with the above-described powder supply continuously or intermittently into the cylinder 50 to which is supplied.

<Thermoplastic resin supply process>
This step is a step of supplying the thermoplastic resin from the supply port 1 into the cylinder 50. The thermoplastic resin supplied into the cylinder 50 in this step is transferred to the first kneading zone 9 through the first transport zone. The first kneading zone 9 is a plasticizing region for plasticizing the thermoplastic resin. In this region, the first kneading zone 9 is melt-kneaded under the condition that the resin pressure in the first kneading zone 9 is 0.1 MPa or more, and the thermoplastic resin is plasticized. Make it. Note that a weight type feeder 16 may be connected to the supply port 1, and a thermoplastic resin may be supplied from the weight type feeder 16 through the supply port 1. Further, one or more other optional components such as an elastomer or an additive may be supplied together with the thermoplastic resin. In addition, one or more weight type feeders 16 ′ and / or capacity type feeders 17 different from the weight type feeder 16 used for supplying the thermoplastic resin are connected to the supply port 1, and an elastomer or an additive 1 or the like is connected. Two or more other components may be supplied through the supply port 1 from a different feeder for each component. In one embodiment, for example, a weight-type feeder 16 ′ and a capacity-type feeder 17 that are different from the weight-type feeder 16 used for supplying the thermoplastic resin are connected to the supply port 1, and the elastomer is weighted. The additive is supplied from the capacity feeder 16 ′ from the capacity feeder 17 through the supply port 1.

As shown in FIG. 1, a biaxial kneading extruder 100 according to the present invention includes a screw 30 for transferring a resin composition in a cylinder 50. The screw 30 of the twin-screw kneading extruder 100 according to the present invention is preferably a screw having two kneading segments from the viewpoint of increasing productivity. The rotational speed of the screw 30 is, for example, 200 to 2000 rpm, and preferably 1000 to 1800 rpm. The higher the number of revolutions, the more frequently the gas-liquid interface is renewed and the lower the equilibrium concentration, so that the VOC devolatilization efficiency can be improved. However, if the rotational speed is too high, the resin deteriorates due to shearing heat generation. Therefore, it is necessary to appropriately adjust the rotational speed in view of the degree of heat generation. The devolatilization of VOC will be described later.

As described above, the twin-screw kneading extruder 100 is set so that the resin pressure in the first kneading zone 9 is 0.1 MPa or more, preferably 0.1 to 5 MPa, more preferably 0.1 to 1 MPa. To drive. A predetermined resin pressure in the first kneading zone 9 may be maintained by appropriately installing a segment capable of adjusting the resin pressure in the first kneading zone 9 of the screw 30. For example, the segment disposed in the first kneading zone 9 includes a segment for sending resin (concept including a resin composition) in the downstream direction by rotating a screw, a segment for pushing the resin back in the upstream direction, or damming the resin. Examples include a segment having an effect. As a segment that pushes the resin back in the upstream direction by the rotation of the screw, a disk generally referred to as a reverse kneading disk (hereinafter referred to as “reverse disk”) whose reverse flight and twist angle exceed 90 ° with respect to the feed direction. For example). A seal ring is mentioned as a segment which has an effect which dams up resin.

Further, one or more so-called kneading disks (hereinafter referred to as “forward disks”) may be disposed at a position upstream of the center of the first kneading zone 9 of the screw 30. A forward disk is a disk whose twist angle is less than 90 ° with respect to the feed direction. If the forward disk is disposed, the degree of plasticization of the thermoplastic resin can be adjusted while efficiently increasing the resin pressure.

In the first kneading zone 9 of the screw, a so-called orthogonal disk having a twist angle of 90 ° can be further arranged as necessary. Further, two or more of these segments may be arranged in combination. The position where the orthogonal disk is arranged is preferably between the aforementioned reverse disk and the sequential disk, or between the sequential disk and the sequential disk. The pressure in the first kneading zone 9 can be measured using a pressure sensor installed in the first kneading zone 9. It is preferable to install one to three pressure sensors in the center to the downstream region of the first kneading zone 9 filled with the resin in the cylinder 50 as necessary. In addition, the pressure sensor must be installed in the cylinder 50 so as not to be damaged by the rotating screw. If the pressure sensor is located deeper in the direction of the screw 30 than the wall surface of the cylinder inner wall, the resin accumulates in the pressure sensor and accurately measures the pressure. Since it becomes impossible, it is preferable to install the tip of the pressure sensor at a position that matches the wall surface of the cylinder inner wall as much as possible.

<Powder supply process>
This step is a step of supplying the powder from the screw-type side feeder 2 into the cylinder 50 to which the above-described thermoplastic resin is supplied. As shown in FIG. 1, the screw side feeder 2 is connected to a weight type feeder 3. Therefore, first, powder is supplied to the weight-type feeder 3, and the powder is transferred from the weight-type feeder 3 to the screw-type side feeder 2. Powder is supplied from the screw-type side feeder 2 into the twin-screw kneading extruder 100.

At this time, the conveying capacity of the powder of the screw-type side feeder 2 is preferably 1.2 times or more of the effective volume per unit time of the powder supplied from the weight-type feeder 3 to the screw-type side feeder 2, and more Preferably, it is 2 times or more, more preferably 4 times or more. Moreover, although the upper limit of the powder conveyance capacity of the screw-type side feeder 2 depends on the design and durability of the apparatus, it is usually per unit time of the powder supplied from the weight-type feeder 3 to the screw-type side feeder 2. The effective volume is 10 times or less.

The powder conveying ability of the screw-type side feeder 2 means the volume per unit time of the powder supplied from the screw-type side feeder 2 to the biaxial kneading extruder 100.

As a method for calculating the conveyance capacity, the product of the volume of space sent to the front of the feeder (that is, the direction of the cylinder 50 in FIG. 1) and the screw rotation speed while the screw of the screw-type side feeder 2 makes one rotation, or the screw The difference between the volume of the cylinder barrel per screw length of the screw of the side feeder 2 and the volume of the screw per lead length of the screw side feeder 2 and the screw rotation speed of the screw side feeder 2 are obtained. be able to. The effective volume of the powder must be evaluated based on the volume actually supplied to the side feeder.

Powder is weighed by the weight type feeder 3 connected to the upper part of the screw type side feeder 2 and supplied to the screw type side feeder 2 by natural fall. The effective volume per unit time of the powder supplied from the weight-type feeder 3 to the screw-type side feeder 2 is the weight of the powder supplied from the weight-type feeder 3 to the screw-type side feeder 2 per unit time. It can be determined as a value divided by the density. In this specification, the “bulk density of the powder” means that the powder is measured from the same height as when the powder is actually supplied from the weight-type feeder 3 to the screw-type side feeder 2, and a measuring container such as a measuring cylinder is used. And the weight of the powder in the measuring container is divided by the volume of the powder measured in the measuring container. The conveying capacity of the screw-type side feeder 2 is preferably at least twice the effective volume per unit time of the powder supplied from the weight-type feeder 3 to the screw-type side feeder 2.

Further, when the powder is supplied to the biaxial kneading extruder 100 with the screw-type side feeder 2, 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 2 is sufficiently larger than the total amount of the effective volume of the powder supplied from the weight-type feeder 3 to the screw-type side feeder 2 and the volume of the resin pellets, the screw-type side feeder 2 There is no need to consider the volume of the resin pellets when setting the feeding capacity of the feeder. From the viewpoint of more stably supplying the powder to the biaxial kneading extruder 100, the powder and the resin pellets of 25 parts by weight or more with respect to 100 parts by weight of the powder pass from the weight type feeder through the screw type side feeder. It is preferable to be supplied to the biaxial kneading extruder 100. The resin pellet supplied from the weight type feeder 3 through the screw type side feeder 2 into the cylinder 50 is 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 3 through the screw type side feeder 2 to the biaxial kneading extruder 100 include thermoplastic resin pellets having an (apparent density) / (true density) of 0.9 or more. There is no restriction on the transition temperature. Furthermore, the above-described thermoplastic resin may be additionally supplied together with the powder through the screw-type side feeder 2.

In addition to the weight-type feeder 3, one or more weight-type feeders 3 'and / or capacity-type side feeders are connected to the screw-type side feeder 2, and the above-mentioned thermoplastic resin and / or a plurality of types of optional components are added to each component. You may supply into the biaxial kneading extruder 100 through the weight type feeder 3 'and / or the capacity | capacitance type side feeder and the screw type side feeder 2 which are different for every.

In one embodiment, in addition to the weight-type feeder 3, a weight-type feeder 3 ′ is connected to the screw-type side feeder 2, and thermoplastic resin is added into the biaxial kneading extruder 100 through the weight-type feeder 3 ′ and the side feeder 2. Supply.

The thermoplastic resin supplied from the supply port 1 in the above steps and the powder supplied using the screw-type side feeder 2 are conveyed to the second kneading zone 10 through the second conveyance zone.

<Melting and kneading process>
In the melt-kneading step, the above-described thermoplastic resin (which may be a resin composition) is melt-kneaded in the cylinder 50 (more specifically, the first to third kneading zones, particularly the first to second kneading zones). It is a process to do. In the second kneading zone 10, the thermoplastic resin and the powder conveyed to the second kneading zone 10 are kneaded, and the powder is uniformly dispersed in the thermoplastic resin, thereby including the thermoplastic resin and the powder. A resin composition is produced.

The biaxial kneading extruder 100 is operated so that the resin pressure in the second kneading zone 10 is less than 5 MPa, preferably less than 3 MPa, more preferably less than 1 MPa. From the viewpoint of sufficiently dispersing the powder supplied from the screw-type side feeder, the resin pressure in the second kneading zone 10 is preferably 0.02 MPa or more, and more preferably 0.1 MPa or more. The resin pressure in the first kneading zone at this time is as described above.

A predetermined resin pressure in the second kneading zone 10 may be maintained by appropriately installing a segment capable of adjusting the resin pressure in the second kneading zone 10 of the screw 30. For example, in the second kneading zone 10, for example, on the downstream side of the center in the second kneading zone 10, a segment that pushes back the resin in the upstream direction by rotation of the screw or a segment that has an effect of blocking the resin is disposed. By doing so, the resin pressure may be maintained. By arranging such a segment, if the above-mentioned pressure is maintained in the second kneading zone 10, volatile components contained in the gas or raw material mixed into the twin-screw kneading extruder 100 as the powder is supplied The ratio of the gas or the volatile component flowing back to the upstream side of the biaxial kneading extruder 100 can be reduced by increasing the rate of escape to the downstream side of the biaxial kneading extruder 100.

The gap distance (chip clearance) from the stirring edge, which is the outermost peripheral end surface of the segment such as an inverted disk installed downstream of the second kneading zone 10, to the inner wall of the cylinder is equal to the gap distance from the normal flight top to the inner wall of the cylinder. It is common. However, the gap distance of the kneading disk used in the second kneading zone 10 is preferably 2 to 3 times the usual distance. With such a gap distance, the resin pressure in the second kneading zone 10 can be controlled within the pressure range described above.

In general, the thickness in the axial direction (disk width) of each kneading disk is usually about 0.1D to 0.2D (D is the screw diameter) in many cases. On the other hand, in the 2nd kneading zone 10 concerning this embodiment, it is preferred to set it as 0.3D or more, and it is more preferred to set it as 0.5D or more. Under such conditions, the thermoplastic resin and the powder are melt-kneaded so that the powder is uniformly dispersed in the thermoplastic resin.

The gas or volatile component is removed to the outside of the biaxial kneading extruder 100 from the first vent port 4 downstream from the second kneading zone 10. A gas or a volatile component may be released to the atmosphere from the first vent port 4, and a vacuum pump may be connected to the first vent port 4 and sucked under reduced pressure. Next, it transfers to the 3rd kneading zone 11 through the 3rd conveyance zone.

(Kneading dispersion process)
In the kneading and dispersing step, the resin composition obtained by kneading in the above-described step is supplied with water from the water inlet 5 to the water pouring and dispersing zone 13 in the third kneading zone 11 to knead and disperse the resin composition. Thus, the volatile component in the resin composition is vaporized together with water and removed from the second vent port 6.

In one embodiment, in the kneading and dispersing step, the resin is further filled in the cylinder 50 and the pressure is increased to a desired pressure, and water is supplied to the resin composition by supplying water to the resin composition. It includes a water injection dispersion step for mixing and dispersing, and a pressure reduction expansion step for removing the VOC contained in the resin by foaming the water mixed and dispersed in the resin under reduced pressure in the water injection dispersion step. Hereinafter, each step will be described.

<Charge boosting process>
The resin obtained in the above process is further transferred downstream of the first vent port 4. Subsequently, in the filling pressure increasing step, the resin composition is filled in the cylinder 50 in the filling pressure increasing zone 12, and the pressure is increased. Preferably, it is desirable to appropriately increase the resin pressure by appropriately arranging segments such as a forward disk.

In the water injection dispersion step to be described later, in the water injection dispersion zone 13, the resin composition to be transferred is pressurized in the filling pressure increase zone 12 in order to suppress the water injection and vaporization to some extent and disperse it in the resin. It is necessary to maintain the state.

A seal ring 8 may be disposed between at least one of the filling pressure increase zone 12 and the water injection dispersion zone 13 and at least one of the water injection dispersion zone 13 and the decompression expansion zone 14, preferably both. If the seal ring 8 is installed, the resin can be blocked. In the case where it is installed both between the filling pressure increase zone 12 and the water injection dispersion zone 13 and between the water injection dispersion zone 13 and the decompression expansion zone 14, seals at the upstream end and the downstream end of the water injection dispersion zone 13 are provided. Dam the resin with the ring. If it is the said structure, it will suppress that the resin kneaded flows back upstream, maintaining the state pressure | voltage-risen in the filling pressure | voltage rise zone 12. FIG.

<Water injection dispersion process>
The water injection dispersion step is a step of mixing and dispersing water in the resin in the water injection dispersion zone 13 following the above-described filling pressure increasing step. Resin is transferred to the water injection dispersion zone 13. Water is injected from the water injection port 5 provided upstream of the center of the water injection dispersion zone 13. The water is injected by, for example, connecting the water injection port 5 to the water injection nozzle 5 'and further connecting the nozzle to a liquid pump or the like. The amount of water supplied to the water injection dispersion zone is preferably 0.1 parts by weight or more and less than 5 parts by weight with respect to the total weight of the raw materials supplied into the cylinder 50, and 0.3 parts by weight or more. The amount is more preferably less than 4 parts by weight, and still more preferably 0.5 parts by weight or more and less than 3 parts by weight. It is preferable to efficiently disperse water in the resin using a desired segment or the like disposed in the water injection dispersion zone 13. As such a segment, for example, a segment such as an orthogonal disk with little change in pressure state and a stirring effect can be cited.

The resin pressure in the water injection dispersion zone 13 is 1 MPa or more. The resin pressure in the water injection dispersion zone 13 is preferably about 1 to 5 MPa, more preferably 1 to 4 MPa, and even more preferably 1 to 3 MPa.

<Decompression expansion process>
The decompression expansion step is a step of removing VOC contained in the resin by foaming the water mixed and dispersed in the resin in the water injection dispersion step described above under reduced pressure.

The resin composition in which water is mixed and dispersed is transferred to the vacuum expansion zone 14. In the decompression / expansion zone 14, using the segments installed in the decompression / expansion zone 14, the water mixed and dispersed in the resin is foamed under reduced pressure to greatly increase the bubble-resin interface.

VOC contained in the resin is efficiently removed from the second vent port 6 by firing water. The segment used in the decompression / expansion zone 14 may be only a flight screw having a conveyance capability, or may be a combination of two or more segments such as an orthogonal disk or a gear kneading disk and a mixing disk having a mixing effect. Good. The vent port 6 may be connected to the opening provided in the upper part of the cylinder 50 through a vacuum pump for suction under reduced pressure, or from the side of the cylinder 50 for the purpose of suppressing bent-up or entrainment phenomenon of the molten resin. Alternatively, vacuum devolatilization may be performed using the devolatilizer 7 equipped with the biaxial screw.

(Other processes)
The method for producing a resin composition according to the present invention may further include a step of supplying an optional component depending on the purpose. As an arbitrary component, what was described in the item (arbitrary component) of the item of the above-mentioned raw material is mentioned.

These optional components such as additives may be supplied into the biaxial kneading extruder 100 from the supply port 1 in the first conveying zone of the biaxial kneading extruder 100 together with the thermoplastic resin, or in the second conveying zone. Or you may supply into the biaxial kneading extruder 100 from the supply port provided in the 3rd conveyance zone. In addition, as described above, when the weight type feeder 16 is connected to the supply port 1 and the thermoplastic resin is supplied from the weight type feeder 16 through the supply port 1, the additive is supplied together with the thermoplastic resin. May be. In addition, one or more weight-type feeders 16 ′ and / or capacitive feeders 17 different from the weight-type feeder 16 used for supplying the thermoplastic resin are connected to the supply port 1, and a plurality of types of optional components are added to each of them. You may supply through the said supply port 1 from the weight type feeder 16 'and / or the capacity | capacitance type feeder 17 which differ for every component. Furthermore, you may supply into the biaxial kneading extruder 100 with a powder through the weight type feeder 3 and the screw type side feeder 2. FIG. Further, in addition to the weight-type feeder 3, one or more weight-type feeders 3 'and / or capacity-type side feeders are connected to the screw-type side feeder 2, and a plurality of kinds of optional components are different for each component. Alternatively, the biaxial kneading extruder 100 may be supplied through the capacity-type side feeder and the screw-type side feeder 2.

In addition, if necessary, a granulating step for connecting the granulating device or the like for pelletizing the resin composition to the downstream of the biaxial kneading extruder 100 and making the resin composition into a pellet shape is included. Also good.

Furthermore, after the granulation step, a VOC residual amount measurement step of measuring the VOC residual amount in the obtained resin composition using a gas chromatograph or the like may be included as necessary.

[2. Twin screw kneading extruder
The main configuration and operation of the twin-screw kneading extruder 100 according to the present invention are as described above. Here, the changeable points of each configuration and configurations not shown will be described.

The biaxial kneading extruder 100 according to the present invention is a biaxial kneading extruder that kneads a resin composition raw material while melting it and extrudes the resin composition obtained by kneading in a shape such as a pellet shape. Therefore, two kneading screws 30 for kneading the resin are accommodated in the cylinder 50 so as to be freely rotatable.

The supply port 1 may have a configuration such as a hopper. Moreover, the screw-type side feeder 2 includes a biaxial screw-type side feeder. A plurality of supply ports and screw side feeders for supplying each raw material into the cylinder 50 may be provided. A drain pot and a vacuum pump may be further connected to the devolatilizer 7.

(Configuration of screw 30)
As the screw configuration of the first kneading zone 9, only a forward disk or, if necessary, an orthogonal disk or a reverse disk can be used in combination. If only the forward disk is used, the degree of fullness of the kneading zone is lowered and the pressure is not increased so much that the thermoplastic resin can be conveyed downstream in a semi-molten state without being completely plasticized. Moreover, it is preferable that the resin pressure be increased to 0.1 MPa or more.

In the kneading of the second kneading zone 10, a part of the volatile matter generated in the second kneading zone 10 is removed from the first vent port 4 downstream from the second kneading zone 10, while the above-mentioned semi-molten resin is mixed. The purpose is to gradually knead and disperse the powder. Therefore, the screw configuration of the second kneading zone 10 is mainly a forward disk, and a wide disk is preferable. Further, it is preferable that the gap distance (chip clearance) is wider than usual.

For the filling pressure increase zone 12, the disk is preferably thinner in order to quickly increase the pressure to 1 MPa or more required for the water injection dispersion zone 13. In addition, in the water injection dispersion zone 13, it is preferable that the thickness of the disk is thin in order to efficiently mix and disperse the water injected in a short section into the resin.

Screws in portions other than the first, second, and third kneading zones described here, that is, a first transport zone (feed zone) upstream of the first kneading zone, and a transport zone between each kneading zone and the kneading zone Alternatively, it is preferable to use a full flight screw in the full pressure zone of the tip. As an example, two full flight screws are used. However, when it is desired to increase the conveyance volume, a square flight or half angle flight shaped screw or a single full flight screw may be used.

The biaxial kneading extruder 100 of the present invention is the above-mentioned [1. It can be suitably used in the production method described in the production method of the resin composition].

[3. (Granulation system)
Moreover, the granulation system provided with the biaxial kneading extruder for manufacturing the pellet of a resin composition using the above-mentioned manufacturing method is also within the scope of the present invention.

In the granulation system of the present invention, for example, a granulation apparatus for pelletizing the resin composition is provided downstream of the twin-screw kneading extruder. Furthermore, an apparatus for measuring the remaining amount of VOC may be provided.

According to the present invention, in the production of a resin composition in which a 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. Thus, it is possible to provide a method that enables production with high efficiency without any trouble and can reduce VOC remaining in the resin composition, and its industrial value is great.

[4. (Summary)
That is, the present invention includes any of the following 1) to 9).
1) A method for producing a resin composition using a biaxial kneading extruder, wherein the resin composition contains a thermoplastic resin and powder as raw materials of the resin composition, and the biaxial The kneading extruder includes a cylinder, a screw-type side feeder connected to the cylinder, a weight-type feeder connected to the screw-type side feeder, and a screw installed in the cylinder. The cylinder includes a supply port, a connection port of the screw-type side feeder, a first vent port, a water injection port, and a second vent port in order from the upstream side of the cylinder. And the screw includes a first kneading zone located between the supply port and the connection port of the screw-type side feeder, and the screw-type side-feed. Comprising a second kneading zone located between the connection port of the feeder and the first vent port, and a water injection devolatilization zone located downstream of the first vent port, the water injection devolatilization zone Is composed of, in order from the upstream of the cylinder, a full pressure increase zone, a water injection dispersion zone where the water injection port is located, and a vacuum expansion zone where the second vent port is located. Supplying the powder from the supply port into the cylinder and supplying the powder from the gravimetric feeder through the screw-type side feeder into the cylinder, and the resin pressure in the first kneading zone is 0. A melt-kneading step of producing a resin composition containing the thermoplastic resin and powder by melt-kneading under a condition of 1 MPa or more and a resin pressure in the second kneading zone of less than 5 MPa; Kneading dispersion in which water is supplied from the water injection port to the water injection dispersion zone and the resin composition is kneaded and dispersed to vaporize volatile components in the resin composition together with water and remove from the second vent port. The thermoplastic resin has a transition temperature of less than 200 ° C., and the powder comprises an inorganic filler having an apparent density of 0.1 to 1.5 g / ml and an apparent density of 0.1 to 1.0 g / ml and one or more kinds of powder selected from the group consisting of thermoplastic resin powders having a transition temperature of 200 ° C. or higher, and the conveying ability of the screw-type side feeder is from the weight-type feeder to the screw-type The effective volume per unit time of the powder supplied to the side feeder is 1.2 times or more. In the kneading and dispersing step, the amount of water supplied to the water injection dispersion zone is Less than 5 parts by weight or more 0.1 parts by weight based on the total feed weight of the raw material into the Nda, resin pressure in the water injection dispersion zone is 1MPa or more, the production method.
2) The method for producing a resin composition according to 1), wherein the resin pressure in the second kneading zone is less than 3 MPa.
3) The method for producing a resin composition according to 1) or 2), wherein the resin pressure in the water injection dispersion zone is 1 to 5 MPa.
4) The biaxial kneader-extruder is provided with a seal ring between at least one of the filling pressure increase zone and the water injection dispersion zone and between the water injection dispersion zone and the reduced pressure expansion zone 1) to 3). The manufacturing method of the resin composition in any one of.
5) The method for producing a resin composition according to any one of 1) to 4), wherein the biaxial kneading extruder includes a devolatilizer at the second vent port.
6) In the powder supply step, the powder and the resin pellets are supplied from the gravimetric feeder through the screw-type side feeder into the cylinder, and the amount of the resin pellets is 100 parts by weight of the powder. The method for producing a resin composition according to any one of 1) to 5), which is 25 parts by weight or more.
7) The powder is at least one powder 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 1) to 6) The manufacturing method of the resin composition in any one of.
8) A biaxial kneading extruder used for producing a resin composition containing a thermoplastic resin and powder as raw materials, a cylinder, and a screw-type side feeder connected to the cylinder A weight-type feeder connected to the screw-type side feeder, and a screw installed in the cylinder. A supply port for supplying to the cylinder, a connection port of the screw-type side feeder for connecting the screw-type side feeder for supplying the powder into the cylinder, and a gas or a volatile component in the cylinder. A first vent port for removal outside the cylinder, a water injection port for supplying water to the resin composition, A second vent port for vaporizing the volatile component in the resin composition together with the water and devolatilizing, and the inside of the cylinder and the screw are connected to the supply port and the screw-type side feeder. A first kneading zone located between the mouth, a second kneading zone located between the connection port of the screw-type side feeder and the first vent port, and water injection located downstream of the first vent port. A twin-screw kneading extruder comprising a devolatilization zone.
9) A granulation system comprising a twin-screw kneading extruder for producing pellets of a resin composition using the production method according to any one of 1) to 7).

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

For Comparative Examples 1 and 2 and Examples 1 to 4, resin compositions were produced using the same apparatus.

(apparatus)
A resin composition was produced in an apparatus having the same configuration as that of the biaxial kneading extruder 100. The twin-screw kneading extruder 100 used was TEX44αII manufactured by Nippon Steel Co., Ltd., which is a meshing type with a cylinder diameter of 47 mm. The biaxial kneader-extruder had a cylinder and two screw shafts accommodated in the cylinder. Moreover, as the screw-type side feeder 2, a biaxial screw-type side feeder was used. A vacuum pump was connected to the first vent port 4. The 2nd vent port 6 which connected the devolatilizer 7 from the side surface was provided. The water injection port 5 is provided with a water injection nozzle 5 ′. Further, a weight type feeder 16, a weight type feeder 16 ′ and a capacity type feeder 17 were connected to the supply port 1. Further, the weight feeder 3 and the weight feeder 3 ′ were connected to the screw side feeder 2.

The screw corresponding to the first kneading zone 9 includes, in order from the upstream side, a forward (forward feed direction) disc, an orthogonal (neutral) disc, and a screw so that the resin pressure in the first kneading zone is 0.1 MPa or more. Reverse (reverse feed direction) was arranged. The thicknesses of the forward disk, orthogonal disk, and reverse disk were 0.2D (D is the screw diameter). In the part of the screw corresponding to the second kneading zone 10, a forward disk was placed long from upstream so that the resin pressure in the second kneading zone 10 was less than 5 MPa, and finally a reverse disk was placed. The forward disk and the reverse disk each had a thickness of 0.5D. The part of the screw corresponding to the third kneading zone 11 is arranged by using a forward disk, an orthogonal disk and a reverse disk in order from the upstream side so that the resin pressure in the water injection dispersion zone 13 is 1 MPa or more. The disc thickness was also 0.1D.

(material)
Polypropylene pellets and rubber pellets were used as the raw material thermoplastic resin. As the rubber pellets, ethylene-butene copolymer pellets or ethylene-octene copolymer pellets were used.

Talc was used as the powder. The bulk density of talc was measured by simulating the state where the weight type feeder 3 is put into the screw type side feeder 2. That is, the weight of talc per unit volume is measured after dropping from a height of 2.3 m corresponding to the length of the shooter connecting the weight type feeder 3 and the screw type side feeder 2 and receiving it on the measuring cylinder. I asked for it. By this measurement, it was 0.51.

(Evaluation of remaining VOC)
The VOC remaining amount in the resin composition was evaluated by a head space method gas chromatograph using the obtained resin composition pellets. In addition, when the resin composition which does not devolatilize water by only melt kneading is used as a standard, it is preferable that the VOC remaining amount is small.

[Comparative Example 1]
(Operating conditions of the device)
Biaxial kneading extrusion with 50 parts by weight of polypropylene pellets via

weight feeder

16, 5 parts by weight of rubber pellets via weight feeder 16 ′, and additive via capacity feeder 17 per total feed weight of raw materials The biaxial kneading and extruding machine 100 was supplied from the most upstream supply port in the first transport zone of the machine 100. 15 parts by weight of talc is supplied to the weight-

type feeder

3 and 30 parts by weight of polypropylene pellets are supplied to the weight-type feeder 3 ′. The weight-type feeder 3 and the weight-type feeder 3 ′ are supplied to the biaxial screw-type side feeder 2. By doing so, it supplied into the biaxial kneading extruder 100 from the biaxial screw type side feeder. The total supply amount of polypropylene pellets, rubber pellets, and talc supplied into the biaxial kneading extruder 100 was 490 kg / hour. The effective volume of talc supplied from the weight type feeder 3 to the screw type side feeder 2 was 144 L / hour, and the conveying capacity of the screw type side feeder 2 was 801 L / hour. That is, the conveying capacity of the screw-type side feeder 2 was about 5.6 times the volume per unit time of talc supplied from the weight-type feeder 3 to the screw-type side feeder 2. The raw material was melt-kneaded at a screw rotation speed of 1350 rpm of the biaxial kneading extruder 100, and vacuum suction was performed from the first vent port and the second vent port without pouring water from the water injection port. The amount of VOC remaining in the obtained resin composition pellets was set to 1.0 as a reference.

[Example 1]
Using the same apparatus as in Comparative Example 1, a resin composition was produced under different conditions.

Production of the resin composition under the same conditions as in Comparative Example 1 except that the screw rotation speed of the twin-screw kneading extruder 100 is 1500 rpm and 1 part by weight of water is injected from the water injection port 5 in total of the supply weight of the raw materials. Went. The amount of VOC remaining in the obtained resin composition pellets was good, being reduced to 0.57 on the basis of Comparative Example 1 where water injection was not volatilized.

[Example 2]
A resin composition was produced under the same conditions as in Example 1 except that 4 parts by weight of water was injected from the water injection port 5 to the total supply weight of the raw materials. The amount of VOC remaining in the obtained resin composition pellets was good, being reduced to 0.51 on the basis of Comparative Example 1 where water injection was not volatilized.

[Comparative Example 2]
A resin composition was produced under the same conditions as in Example 1 except that 5 parts by weight of water was poured from the water inlet 5 into the total supply weight of the raw materials. As a result, the resin composition extruded from the biaxial kneader-extruder 100 was foamed, and pellets could not be produced.

Example 3
A resin composition was produced under the same conditions as in Example 1 except that the total supply amount of polypropylene pellets, rubber pellets, and talc supplied into the biaxial kneading extruder 100 was 600 kg / hour. The effective volume of talc supplied from the weight type feeder 3 to the screw type side feeder 2 was 176 L / hour, and the conveying capacity of the screw type side feeder was 801 L / hour. That is, the conveying ability of the screw-type side feeder was about 4.6 times the volume per unit time of talc supplied from the weight-type feeder 3 to the screw-type side feeder 2. The amount of VOC remaining in the obtained resin composition pellets was reduced to 0.68 on the basis of Comparative Example 1 in which water injection was not volatilized. Compared with Comparative Example 1, productivity was improved by 20%, and VOC was reduced by 31%, which was favorable.

Example 4
A resin composition was produced under the same conditions as in Example 2 except that the screw rotation speed of the biaxial kneading extruder 100 was 1650 rpm. The amount of VOC remaining in the obtained resin composition pellets was good, being reduced to 0.46 on the basis of Comparative Example 1 where water injection was not volatilized.

The present invention can be used in a method for producing a resin composition in which a thermoplastic resin and powder are melt-kneaded.

1 Supply port 1
2 Screw-

type side feeder

3, 3 ′, 16, 16 ′ Heavy-weight feeder 4 First vent port 5 Water injection port 5 ′ Water injection nozzle 6 Second vent port 7 Devolatilizer 8 Seal ring 9 First kneading zone 10 Second kneading Zone 11 Third kneading zone 12 Filling pressurization zone 13 Injection water dispersion zone 14 Decompression expansion zone 15 Injection water devolatilization zone 17 Capacity type feeder 30 Screw 50 Cylinder 100 Twin screw kneading extruder

Claims

A method for producing a resin composition using a biaxial kneading extruder,
The resin composition includes a thermoplastic resin and powder as raw materials of the resin composition,
The biaxial kneading extruder includes a cylinder, a screw-type side feeder connected to the cylinder, a weight-type feeder connected to the screw-type side feeder, and a screw installed in the cylinder. Has
The cylinder includes a supply port, a connection port of the screw-type side feeder, a first vent port, a water injection port, and a second vent port in order from the upstream side of the cylinder.
The inside of the cylinder and the screw are
A first kneading zone located between the supply port and the connection port of the screw-type side feeder; a second kneading zone located between the connection port of the screw-type side feeder and the first vent port; A water injection devolatilization zone located downstream of the first vent port,
The water injection devolatilization zone includes, in order from the upstream of the cylinder, a filling pressure increase zone, a water injection dispersion zone where the water injection port is located, and a vacuum expansion zone where the second vent port is located,
Supplying the thermoplastic resin from the supply port into the cylinder;
Supplying the powder from the gravimetric feeder through the screw-type side feeder into the cylinder; and
Melting and kneading under the conditions that the resin pressure in the first kneading zone is 0.1 MPa or more and the resin pressure in the second kneading zone is less than 5 MPa to produce a resin composition containing the thermoplastic resin and powder. A melt kneading step,
Kneading and dispersing by supplying water from the water injection port to the water injection dispersion zone and kneading and dispersing the resin composition to vaporize volatile components in the resin composition together with water and remove them from the second vent port. A process,
The thermoplastic resin has a transition temperature of less than 200 ° C.,
The powder is 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. More than kinds of powders,
The conveying capacity of the screw-type side feeder is 1.2 times or more the effective volume per unit time of the powder supplied from the weight-type feeder to the screw-type side feeder,
In the kneading and dispersing step, the amount of water supplied to the water injection dispersion zone is not less than 0.1 parts by weight and less than 5 parts by weight with respect to the total supply weight of the raw material into the cylinder. The manufacturing method whose resin pressure in a zone is 1 Mpa or more.
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 a resin pressure in the water injection dispersion zone is 1 to 5 MPa.
The biaxial kneading extruder is
The resin composition according to any one of claims 1 to 3, further comprising a seal ring between at least one of the filling pressure increasing zone and the water injection dispersion zone and between the water injection dispersion zone and the reduced pressure expansion zone. Manufacturing method.
The method for producing a resin composition according to any one of claims 1 to 4, wherein the biaxial kneading extruder includes a devolatilizer at the second vent port.
In the powder supply process, the powder and the resin pellets are supplied into the cylinder from the gravimetric feeder through the screw side feeder,
The method for producing a resin composition according to any one of claims 1 to 5, wherein the amount of the resin pellet is 25 parts by weight or more with respect to 100 parts by weight of the powder.
7. The powder according to claim 1, wherein the powder is at least one powder 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.
As a raw material, a biaxial kneading extruder used for producing a resin composition containing a thermoplastic resin and powder,
A cylinder, a screw-type side feeder connected to the cylinder, a weight-type feeder connected to the screw-type side feeder, and a screw installed in the cylinder,
The cylinder is connected to the supply port for supplying the thermoplastic resin into the cylinder and the screw-type side feeder for supplying the powder into the cylinder in order from the upstream of the cylinder. A connection port of the screw-type side feeder, a first vent port for removing gas or volatile components in the cylinder to the outside of the cylinder, a water injection port for supplying water to the resin composition, and the resin A second vent port for vaporizing the volatile components in the composition together with the water and devolatilizing,
The inside of the cylinder and the screw are
A first kneading zone located between the supply port and the connection port of the screw-type side feeder; a second kneading zone located between the connection port of the screw-type side feeder and the first vent port; The biaxial kneading extruder comprised including the water injection devolatilization zone located downstream of the first vent port.
A granulation system comprising a biaxial kneading extruder for producing pellets of a resin composition using the production method according to any one of claims 1 to 7.