JP5979765B2 - Microfibrillated cellulose composite resin material production apparatus and production method - Google Patents

Description

  The present invention relates to a microfibril capable of continuously producing a microfibrillated cellulose composite resin material in which microfibrillated cellulose is produced from a cellulose-containing raw material and the produced microfibrillated cellulose is dispersed in a thermoplastic resin. The present invention relates to an apparatus and a method for producing a cellulose composite resin material.

  Biodegradable plastics have been expected to play a role in the transition to a resource-recycling society in consideration of the global environment, and commercial production of biodegradable plastics using polylactic acid as a resin raw material has also begun. As a method for reinforcing biodegradable plastics, biodegradable fiber-reinforced composite resin materials using microfibrillated cellulose have attracted attention and are being developed. Microfibrillated cellulose is also being developed as a resin fiber reinforcing material that replaces glass fibers.

  Patent Document 1 proposes a resin composite material in which microfibrillated cellulose whose surface is coated with a hydrophilic resin is used as a fiber reinforcing material. This resin composite material can be obtained by first mixing microfibrillated cellulose and a hydrophilic resin, dehydrating them, adding a base material resin, and mixing them. And as a mixing means, various kneaders, such as a roll, a Banbury mixer, a kneader, and a twin screw kneading extruder, can be used. Among these, a twin screw kneading extruder is preferable because the above process can be performed in series. It is described.

  Patent Document 2 proposes a method for producing an aliphatic polyester composition, pulp and cellulosic fibers used therefor, and a method for microfibrillation thereof. And after processing pulp or cellulosic fiber by refiner processing, media stirring mill processing, vibration mill processing, stone mill type processing, etc., in the presence of cellulose amorphous region swelling agent using a twin screw extruder, resin component and It is described that an aliphatic polyester composition in which the fiber component is defibrated and uniformly finely dispersed in the resin component is obtained by melt-kneading the fiber component obtained by the treatment.

  Although this microfibrillated cellulose is said to be obtained by grinding and / or beating pulp, Patent Document 3 discloses a method for producing nanofibers that can obtain finer fibers further microfibrillated. Has been proposed. In this nanofiber manufacturing method, first, a cellulose-based fiber raw material is wet-disaggregated, then the disaggregated fiber raw material is preliminarily defibrated, and then the pre-defibrated fiber raw material is steamed, and then steamed. This is carried out by microfibrillation of the treated fiber raw material. And it is described that the preliminary defibrating process can use a refiner, a medium stirring mill, a vibration mill, a stone mill, and the microfibrillation process can be efficiently performed by a twin screw extruder. Yes.

JP 2008-184492 A JP 2005-42283 A JP 2008-75214 A

  The twin screw extruder is widely used for mixing, plasticizing, extrusion molding and the like of thermoplastic resins. And as described in Patent Document 2 or 3, the twin screw extruder is used for kneading microfibrillated cellulose and resin, and as a processing device for fibrillating cellulose raw materials such as pulp to microfibrillation. It is used.

  However, using a twin-screw extruder, a method of performing a series of steps of a microfibrillation step for producing microfibrillated cellulose from a cellulose raw material and a step of kneading the obtained microfibrillated cellulose with a resin to obtain a composite material or No device has been proposed yet. This is because it is difficult to perform the above two steps in succession with one extruder, or efficient processing cannot be performed. One of the reasons for this difficulty is that the space volume composed of the cylinder and screw of the twin screw extruder is a twin screw extruder that performs microfibrillation treatment, and a twin screw that kneads microfibrillated cellulose and resin. This is because the basic configuration of the twin screw extruder is different.

  For this reason, it is conceivable to use a twin screw extruder having a different basic configuration, but there is a problem that the microfibrillated cellulose is dehydrated and difficult to transfer at the connecting portion by simply connecting the pipes. Moreover, even if it connects via a pressurization pump, there exists a problem that the microfibrillation cellulose stays in a connection part and quality deteriorates, and there exists a problem that an installation enlarges.

  In view of such conventional problems, the present invention comprises a microfibrillation step for producing microfibrillated cellulose from a cellulose raw material, and a step of kneading the obtained microfibrillated cellulose with a resin to obtain a composite material. An object of the present invention is to provide a microfibrillated cellulose composite resin material production apparatus and production method that can be performed in series and are excellent in work efficiency and production efficiency.

  The microfibrillated cellulose composite resin material manufacturing apparatus according to the present invention includes a twinning extruder for defibrating that performs defibrating treatment of a cellulose-containing raw material to generate and pressurize microfibrillated cellulose, and the pumped microfibrils. A twin-screw extruder for kneading, which receives the modified cellulose, kneads it with the resin raw material, performs dehydration and plasticization, and supplies the composite resin material in which the microfibrillated cellulose is dispersed to the molding apparatus.

  In the above invention, the defibrating twin screw extruder may have a connecting pipe for pumping the produced microfibrillated cellulose to the kneading twin screw extruder.

  In addition, the defibrating twin screw extruder preferably has a liquid addition pump for adding a fluidizing agent to the microfibrillated cellulose fed to the kneading twin screw extruder.

  The twin-screw extruder for kneading preferably has a kneading zone, a dewatering zone, a plasticizing zone, and a vacuum dewatering zone in order from the upstream side. The dewatering zone has a kneading screw and has a temperature of 200 ° C. or lower. It should be a heating zone.

  In the above invention, the kneading twin-screw extruder preferably has a cylinder whose inner diameter is larger than the inner diameter of the cylinder of the defibrating twin-screw extruder.

  The apparatus for producing a microfibrillated cellulose composite resin material according to the present invention can be provided with a plurality of defibrating twin screw extruders.

  The method for producing a microfibrillated cellulose composite resin material according to the present invention comprises the steps of defibrating a cellulose-containing raw material to produce microfibrillated cellulose, kneading the produced microfibrillated cellulose and resin, dehydrating and plasticizing A method for producing a microfibrillated cellulose composite resin material, in which a composite resin material in which microfibrillated cellulose is dispersed is continuously produced and the resin is not completely melted, and the kneaded product is wound up or ejected. It can be carried out by gradually dehydrating so that the resin is plasticized and then dehydrating under reduced pressure.

  According to the present invention, a microfibrillation step for producing microfibrillated cellulose from a cellulose raw material, and a step of kneading the obtained microfibrillated cellulose with a resin to obtain a composite material can be carried out in series. An apparatus and a method for producing a microfibrillated cellulose composite resin material excellent in production efficiency can be provided.

It is a schematic diagram which shows the structure of the microfibrillated cellulose composite resin material manufacturing apparatus which concerns on this invention. It is a schematic diagram which shows the other Example of the microfibrillation cellulose composite resin material manufacturing apparatus which concerns on this invention of the structure which connected the several twin screw extruder for fibrillation to the twin screw extruder for kneading | mixing.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 1 shows an example of an apparatus for producing a microfibrillated cellulose composite resin material according to the present invention. As shown in FIG. 1, the present microfibrillated cellulose composite resin material production apparatus comprises a twinning extruder 10 for defibrating that performs defibrating treatment of a cellulose-containing raw material to produce and pressurize microfibrillated cellulose, and its A twin screw extruder 20 for kneading that can receive the pumped microfibrillated cellulose, knead it with the resin raw material, dehydrate and plasticize and supply the composite resin material in which the microfibrillated cellulose is dispersed to the molding apparatus; ,have.

  The defibrating twin screw extruder 10 is provided with a raw material supply port 13 on the upstream side of the defibrating twin screw extruder body 11, and the microfibrillated cellulose produced in the microfibrillation zone 11a is mixed with the twin screw extruder for kneading. It has a connecting pipe 15 that is pumped to the machine 20. Further, the defibrating twin screw extruder 10 is provided with a liquid addition pump 17 for adding a fluidizing agent for improving the fluidity of the microfibrillated cellulose on the downstream side. The microfibrillated cellulose produced in the microfibrillated zone 11a reacts with the fluidizing agent or adsorbs the fluidizing agent in the reaction zone 11b, and its fluidity is enhanced. The fluidization treatment of the microfibrillated cellulose facilitates continuous pumping of the produced microfibrillated cellulose to the twin screw extruder 20 for kneading.

  As the fluidizing agent, a commercially available paper-making paper strength enhancer can be used. The paper-making paper strength enhancer may be anionic or cationic, and any dry or wet paper-making strength enhancer can be used as a fluidizing agent. The viscosity of the paper-making paper strength enhancer is not preferred, for example, as low as about 100 mPa · s.

  The defibrating twin screw extruder 10 is preferably provided with a weight type feeder so that a certain amount of raw material can be supplied from the raw material supply port 13. The material supply port 13 preferably has a shape in which the opening is long in the downstream direction so that the material quickly enters the space between the screw and the cylinder. Furthermore, in order to reliably carry out defibration at a low temperature, a longer cylinder is better.However, if the length is too long, not only a large torque is required to rotate the screw, but also a large torsional stress is applied to the screw shaft. Absent.

  The connecting pipe 15 is not particularly limited as long as it connects the defibrating twin screw extruder 10 and the kneading twin screw extruder 20 and can continuously feed the material. However, the connecting pipe 15 having a capacity that does not apply high pressure to the outlet of the defibrating twin screw extruder 10 is preferable because the fibrillated cellulose is difficult to separate from water. Further, it is not preferable that the connecting pipe 15 has a shape that rapidly reduces the cross-sectional area from the outlet of the defibrating twin-screw extruder 10 or an extremely thin pipe diameter. Specifically, the connecting pipe 15 has a pressure of about 0.1 to 0.5 MPa at which the pressure of the connecting pipe 15 near the outlet of the defibrating twin screw extruder 10 does not affect the microfibrillation zone. It is preferable that the area is 30% to 50% of the sectional area of the tip of the defibrating twin screw extruder 10. The pipe inner surface of the connecting pipe 15 does not need to be surface-treated, but it is preferable to perform a surface treatment such as chrome plating in order to avoid the attachment of a deteriorated product due to staying.

  In the kneading twin-screw extruder 20, a resin supply port 23 is provided on the upstream side of the kneading twin-screw extruder body 21, and a connecting pipe 15 is connected to the downstream side of the resin supply port 23. The microfibrillated cellulose produced by the defibrating twin screw extruder 10 is pumped to the kneading twin screw extruder 20 through the connecting pipe 15. The microfibrillated cellulose received in the kneading twin-screw extruder 20 is kneaded with the resin supplied from the resin supply port 23 in the kneading zone 21a of the kneading twin-screw extruder main body 21, and dehydrated in the dewatering zone 21b. Is done. The dehydrated microfibrillated cellulose and resin are kneaded at the same time as plasticization of the resin in the plasticization zone 21c, and then further dehydrated in the vacuum dehydration zone 21d to produce a microfibrillated cellulose composite resin material. Is done.

  The microfibrillated cellulose composite resin material discharged from the die 27 installed at the tip of the kneading twin-screw extruder 20 is supplied to the strand cutter 40 via the belt conveyor 45 to produce a product (granular material). . The resin supply port 23 is preferably provided with a weight type feeder in order to quantitatively supply the resin. In addition, since the microfibrillated cellulose composite material may deteriorate or carbonize after being discharged from the die 27 due to heat storage, it is desirable to immediately cool the product on the belt conveyor 45 using a cooling means such as cold air or mist. . Furthermore, when the cooling is not in time, it is preferable to increase the cooling capacity by using a water tank (strand bath) instead of the belt conveyor 45.

  In the kneading zone 21a, it is necessary to appropriately adjust the screw shape and the cylinder temperature so that the resin does not melt completely. This is because when the resin is completely melted, rapid dehydration is performed in the dehydration zone 21b, and microfibrillated cellulose or resin may be ejected outside the cylinder.

  In the dehydrated zone 21b, the water in the microfibrillated cellulose is gradually dehydrated through the dehydration port 24. However, if the water is removed too much, the microfibrillated cellulose aggregates in the plasticizing step, and the microfibrillated cellulose cannot be uniformly dispersed in the resin. Therefore, it is important to control the amount of dehydration. In order to control the amount of dewatering in the dewatering zone 21b, it is necessary to optimize three factors: the setting of the cylinder temperature, the rapid supply of heat using shear heat generation, and the surface renewal by the screw. It is desirable to set the cylinder temperature as high as possible within the range where the product temperature of the dehydration zone 21b does not exceed the softening point or melting point of the resin, but if it exceeds 200 ° C, the microfibrillated cellulose in contact with the cylinder will deteriorate. It is better to adjust it to 200 ° C or less.

  In addition, it is desirable to provide a kneading screw in the dehydration zone 21b to promote the surface renewal (position exchange) of the material and to generate the latent heat of evaporation lost by evaporation of water by appropriately generating shear heat. However, since the resin is melted or softened due to local heat generation due to shearing or the microfibrillated cellulose is deteriorated, care must be taken not to make the shear stress too strong. Further, in order to facilitate dehydration gradually, it is preferable to increase the spatial volume of the dehydration zone 21b. Further, the vent can be partially decompressed to lower the boiling point, and dehydration can be performed at a temperature as low as possible.

  In the vacuum dehydration zone 21d, vacuum dehydration is performed by the vacuum dehydrating means 30 through the vent ports 37A and 37B. The vacuum dehydrating means 30 has a vacuum pump 33 and a trap 35. In the vacuum dehydration zone 21d, the moisture content of the microfibrillated cellulose composite resin material can be reduced to 5% or less. In the vacuum dehydration, the smaller the residual moisture, the shorter the dehydration time in the subsequent process and the reduction of the dehydration process, which is preferable. In addition, since a large amount of water is removed at the time of dehydration under reduced pressure, it is preferable to use a long vent with a large opening area in order to reduce the gas flow rate at the vent port and prevent vent-up.

  In the above, this microfibrillated cellulose composite resin material manufacturing apparatus was demonstrated. The apparatus for producing a microfibrillated cellulose composite resin material according to the present invention is not limited to the above example. For example, as shown in FIG. 2, there is a microfibrillated cellulose composite resin material production apparatus in which two or more defibrating twin screw extruders (10A, 10B) are connected to a kneading twin screw extruder 20. May be. This configuration is suitable for a mass production type microfibrillated cellulose composite resin material production apparatus.

  Further, the kneading twin-screw extruder can be provided with a cylinder whose inner diameter is larger than the inner diameter of the cylinder of the defibrating twin-screw extruder. In this case, since the spatial volume of the dewatering zone 21b can be increased, the feed rate of the material can be reduced. For this reason, the microfibrillated cellulose can be dehydrated gradually, and the dehydration can be easily controlled.

  In the present invention, the cellulose raw material is not particularly limited. In addition to raw materials from which impurities such as lignin have already been separated, such as pulp and waste paper, wood flour, rice straw, grass, algae, potato, sugar radish, sweet potato, etc. Cellulose raw materials containing impurities can be used. In addition to polyolefin resins such as polypropylene and polyethylene, various resins such as polystyrene, ABS, polycarbonate, polyester including biodegradable resin, and nylon can be used as the resin. In addition to the cellulose raw material and the resin, a compatibilizer, an antioxidant, a colorant, a weathering agent, and the like can be added as necessary.

  A production test for producing a microfibrillated cellulose composite resin material was carried out using the microfibrillated cellulose composite resin material production apparatus shown in FIG. TEX30α L / D59.5 manufactured by Nippon Steel Works was used as the twin screw extruder 10 for defibration, and TEX30α L / D45.5 manufactured by Nippon Steel Works was used as the twin screw extruder 20 for kneading. Refined bleached pulp was used as the cellulose-containing raw material. As the base material of the microfibrillated cellulose composite resin material, polypropylene (PP) and maleic anhydride-modified polypropylene (MAPP) were weighed at a predetermined ratio, and thoroughly mixed and used. As the liquid addition pump 17, 3.6 l / h manufactured by Fuji Pump Co., Ltd. was used. The connecting pipe 15 was an L-shaped steel pipe having an inner diameter of 16 mm and a length of 460 mm.

  In the production test, first, a cellulose-containing raw material was broken to a predetermined size with a Henschel mixer (Super mixer manufactured by Kawata Co., Ltd.), charged into a raw material supply port 13 from a weight type feeder (TTF35 manufactured by Nippon Steel Works, Ltd.), The fluidizing agent was supplied from the liquid addition pump 17 before the fibrillated cellulose reached the fluidizing agent supply port. Before the microfibrillated cellulose is stably supplied from the connecting pipe 15 to the twin-screw extruder 20 for kneading, the resin is supplied from the resin supply port 23 via a weight feeder (STF25 manufactured by Nippon Steel Works). Supplied. Then, after the microfibrillated cellulose and the resin were stably supplied to the kneading twin-screw extruder 20, the vent ports (37A, 38B) of the vacuum dehydration zone 21d were depressurized, and vacuum dehydration was started. .

  Table 1 shows the test results of observing the fluidity of microfibrillated cellulose when various papermaking paper strength enhancers are used as the fluidizing agent. In the fluidity test, bleached pulp and papermaking paper strength enhancer were mixed in a beaker at a solid content ratio of 10: 3, and fluidity was judged by touch. In Table 1, Harima Kasei represents Harima Kasei Co., Ltd., and Seiko PMC represents Seiko PMC Corporation. As shown in Table 1, the microfibrillated cellulose is flowable regardless of which papermaking paper strength enhancer is used, and is supplied to the kneading twin-screw extruder via the connecting pipe of the defibrating twin-screw extruder. Can be pumped. However, the sample D is not preferable as a fluidizing agent in consideration of workability.

  Table 2 shows the results of the operating condition test in which the influence of the cylinder temperature in each zone of the kneading twin-screw extruder 20 and the presence or absence of the dewatering zone is examined. In this operating condition test, the rotational speed of the defibrating twin screw extruder 10 was 400 rpm, and the rotational speed of the kneading twin screw extruder 20 was 200 rpm. The cylinder temperature in the plasticizing zone of the twin screw extruder 20 for kneading was 180-200 ° C. Sample E in Table 1 was used as the fluidizing agent.

  As shown in Table 2, it can be seen that the kneading zone and the dewatering zone have appropriate temperatures, and their temperature control is important. It can also be seen that it is necessary to gradually dehydrate the microfibrillated cellulose in the dehydration zone. In addition, Table 3 shows the raw material composition of bleached pulp, PP resin, MAPP, and fluidizing agent (sample E) used in this operation status test. The discharge amount shown in Table 3 indicates the discharge amount from the tip of the kneading twin-screw extruder 10, and is a value when all the water is dehydrated in the dewatering zone and the vacuum dewatering zone.

10, 10A, 10B Twin screw extruder for defibration
11 Main body of twin screw extruder for defibration
13 Raw material supply port
15 Connection piping
17 Liquid pump
20 Twin screw extruder for kneading
21 Main body of twin screw extruder
23 Resin supply port
24 Dewatering spout
27 die
30 Vacuum dehydration means
33 Vacuum pump
35 traps
37, 37A, 37B Vent port
40 strand cutter
45 Belt conveyor

Claims (8)

A fibrillation twin-screw extruder that generates and fibrillates microfibrillated cellulose by defibrating the cellulose-containing raw material, receives the pumped microfibrillated cellulose, kneads it with the resin raw material, and then dehydrates, An apparatus for producing a microfibrillated cellulose composite resin material, comprising: a kneading twin-screw extruder for supplying a molding apparatus with a composite resin material in which microfibrillated cellulose is dispersed by plasticizing.   2. The microfibrillated cellulose composite resin material producing apparatus according to claim 1, wherein the defibrating twin screw extruder has a connecting pipe for pumping the produced microfibrillated cellulose to the kneading twin screw extruder. .   The microfibrillation according to claim 1 or 2, wherein the defibrating twin screw extruder has a liquid addition pump for adding a fluidizing agent to the microfibrillated cellulose pumped to the kneading twin screw extruder. Cellulose composite resin material manufacturing equipment.   The micro twin screw extruder for kneading has a kneading zone, a dewatering zone, a plasticizing zone, and a vacuum dewatering zone sequentially from the upstream side. Equipment for producing fibrillated cellulose composite resin material. The apparatus for producing a microfibrillated cellulose composite resin material according to claim 4, wherein the dehydration zone has a dehydration amount control means, a kneading screw, and a heating zone of 200 ° C or lower.   The microfibrillation according to any one of claims 1 to 5, wherein the twin screw extruder for kneading has a cylinder whose inner diameter is larger than the inner diameter of the cylinder of the twin screw extruder for defibrating. Cellulose composite resin material manufacturing equipment.   The apparatus for producing a microfibrillated cellulose composite resin material according to any one of claims 1 to 6, wherein there are a plurality of defibrating twin screw extruders. Defibrillation treatment of cellulose-containing raw material to produce microfibrillated cellulose, the resulting microfibrillated cellulose and resin are kneaded, then dehydrated and plasticized to disperse the microfibrillated cellulose A method for producing a microfibrillated cellulose composite resin material for continuously producing a material,
A method for producing a microfibrillated cellulose composite resin material, in which a resin is plastically dehydrated and then dehydrated under reduced pressure after the resin is not melted completely and gradually dehydrated so that the kneaded product is not rolled up or ejected.

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