JP2011093990A - Process for producing cellulose-containing thermoplastic resin, cellulose-containing thermoplastic resin and molded product thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for producing a cellulose-containing thermoplastic resin which can produce a thin-wall molded product by sufficiently solving the ununiformity of the properties without being limited to nanocellulose as non-fibrillated fibrous cellulose, a cellulose-containing thermoplastic resin, and a molded product thereof. <P>SOLUTION: In the process for producing a cellulose-containing thermoplastic resin comprising subjecting at least a thermoplastic resin and non-fibrillated fibrous cellulose to melt kneading in an agitation chamber provided in a batch-wise sealed kneader by high-speed rotation of rotating blades arranged on a rotating shaft, the batch-wise sealed kneader has a water vapor releasing mechanism of releasing excess water vapor formed from the non-fibrillated cellulose in the agitation chamber to the outside and immediately after the rotational torque of the rotating shaft on which the rotating blades are arranged reaches a minimum value and start rising, the melt kneading is completed and the kneaded product is taken out. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a cellulose-containing thermoplastic resin containing non-fibrillated fibrous cellulose, a cellulose-containing thermoplastic resin produced by the production method, and a molded article thereof.

  Fiber Reinforced Plastics (FRP) in which glass fiber, carbon fiber, etc. are dispersed in plastic is lightweight, high in strength, and has good durability. It occupies a large position in the fields of advanced technology fields such as interior and exterior of automobiles and railway vehicles, housing equipment such as unit baths and septic tanks. However, since it is difficult to separate materials, it is often difficult to recycle or dispose of FRP, and when considering the environmental load and life cycle cost, there is a possibility that the material will become more expensive than it seems.

  In FRP, if non-chlorinated thermoplastic resin such as polyolefin resin is used as the base plastic, there is no generation of dioxin even if it is incinerated at the time of disposal, and the environmental load can be reduced. Specifically, since glass fiber is often used as the reinforcing fiber, there is a problem that the glass fiber remains as a residue after incineration. If carbon fiber is used, it does not remain as a residue after incineration, but the carbon fiber itself is expensive, and the one using carbon fiber has a high function and becomes overspec in general use.

  Therefore, in applications such as general building materials and plastic cases that do not require ultra-high properties, a cellulose-containing thermoplastic resin in which fibrous cellulose is dispersed as a reinforcing fiber in a thermoplastic resin has been proposed and used in various fields. (For example, refer to Patent Document 1). The combination of fibrous cellulose and thermoplastic resin was originally proposed as a technique for recycling waste wood and other waste wood such as building waste. However, at present, the use of composite materials of woody materials and plastics as fibrous cellulose is thriving in Europe and the United States, especially in North America, and is manufactured on a scale of 1 million tons per year, most of which is used as exterior deck materials. It's being used. These are called Wood-Plastic-Composites, Wood-Polymer Compositions, Woodfiber-Polymer Compositions, and the like. In these, as the fibrous cellulose, wood materials that are not pretreated such as wood waste materials and plant material chips are often used instead of bleached pulp having high purity.

  A batch type high-speed stirring device such as a Henschel mixer (registered trademark) or a continuous processing device such as a uniaxial kneading and extruding device or a biaxial kneading and extruding device is used to knead the wood material and the thermoplastic resin. (See, for example, Patent Documents 2 to 5). However, in the batch type high-speed stirring device, the finished cellulose-containing thermoplastic resin becomes an indeterminate lump, and in the subsequent molding process, it was necessary to perform pulverization in advance and prepare the shape, Kneading was insufficient and a homogeneous resin could not be obtained. In addition, the cellulose-containing thermoplastic resin produced by the uniaxial kneading extruder and the biaxial kneading extruder is not continuously kneaded because of the continuous type, and the affinity between the thermoplastic resin as the base material and the fibrous cellulose. In many cases, voids are generated at the interface. For this reason, even if bent corners and fibrous cellulose are contained, the strength characteristics commensurate with them cannot be exhibited.

  A method for producing a cellulose-containing thermoplastic resin composition in which an aqueous dispersion of cellulose nanofibers and a thermoplastic resin are mixed using a high-speed stirrer provided with a blade member disposed on a rotating shaft has also been proposed ( For example, see Patent Document 6). A molded body using a cellulose-containing thermoplastic resin containing cellulose nanofibers exhibits an improvement effect excellent in strength characteristics, particularly bending physical properties. However, in order to make a cellulose nanofiber from a woody material such as pulp, the pulp or the like must be microfibrillated with an apparatus such as a homogenizer, a stone mill friction machine, or a refiner. In addition, in order to obtain a cellulose-containing thermoplastic resin having uniform characteristics using cellulose nanofibers that have been microfibrillated, it is necessary that the dimensional uniformity and dispersion uniformity of the cellulose nanofibers be at extremely high levels. there were. However, it is difficult to uniformly microfibrillate as cellulose nanofibers, and a fiber lump that cannot be completely separated may remain, resulting in non-uniform characteristics. Therefore, in a thin molded product, molding defects and insufficient strength may occur. In order to completely eliminate this fiber lump, treatments such as increasing the processing time and increasing the processing strength had to be performed.

Japanese Patent No. 8-118452 JP 2007-084713 A JP 2000-219812 A JP-A-1-118425 JP 2000-273800 A JP 2009-029927 A

  The object of the present invention is not limited to nanocellulose as fibrous cellulose, and is a method for producing a cellulose-containing thermoplastic resin capable of producing a thin-walled molded article that sufficiently eliminates unevenness in characteristics, and cellulose-containing heat. It is in providing a plastic resin and its molded object.

As a result of intensive studies, the present inventors have found that the above-described problems can be solved by the present invention described below.
[1] Cellulose-containing, which melts and kneads at least a thermoplastic resin and non-fibrillated fibrous cellulose by high-speed rotation of a rotary blade disposed on a rotating shaft in a stirring chamber provided in a batch type closed kneading apparatus In the method for producing a thermoplastic resin, the batch-type closed kneading apparatus has a water vapor release mechanism for releasing an excess of water vapor generated from the non-fibrillated fibrous cellulose in the stirring chamber to the outside. The cellulose-containing thermoplastic resin is characterized in that melt kneading is terminated and the material to be kneaded is taken out immediately after the rotational torque of the rotating shaft provided with the rotating blades reaches a minimum value and starts to rise. Production method.
[2] The method for producing a cellulose-containing thermoplastic resin according to the above [1], wherein the moisture content of the non-fibrillated fibrous cellulose is 30 to 90% by mass.
[3] The method for producing a cellulose-containing thermoplastic resin according to the above [1], wherein a mass ratio in a dry state between the non-fibrillated fibrous cellulose and the thermoplastic resin is 10/90 to 70/30.
[4] A cellulose-containing thermoplastic resin produced by the method for producing a cellulose-containing thermoplastic resin according to any one of [1] to [3].
[5] A cellulose-containing thermoplastic resin molded article obtained by injection molding the cellulose-containing thermoplastic resin according to [4].
[6] A cellulose-containing thermoplastic resin molded article obtained by extruding the cellulose-containing thermoplastic resin according to [4].

  According to the above method for producing a cellulose-containing thermoplastic resin of the present invention, a cellulose-containing thermoplastic resin having uniform characteristics can be obtained without using microfibrillated nanocellulose as the fibrous cellulose. Furthermore, if the cellulose-containing thermoplastic resin of the present invention is used, a thin molded product can be obtained. Therefore, a molded body having a complicated shape can be obtained.

The schematic diagram of a batch type closed kneading apparatus. The schematic diagram of the rotating shaft by which the some rotating blade was arrange | positioned. The schematic diagram of the release mechanism of water vapor | steam.

  The non-fibrillated fibrous cellulose in the present invention is not particularly limited as long as the shape is fibrous and the plant cell wall is used as a raw material. For example, natural cellulose such as wood (conifer, broadleaf), cotton linter, kenaf, manila hemp (avaca), sisal hemp, jute, sabaigrass, esparto grass, bagasse, rice straw, straw, straw, bamboo, etc. The component pulp is used. Pulp is pulp obtained by mechanical methods (crushed wood pulp, refiner grand pulp, thermomechanical pulp, semi-chemical pulp, chemi-ground pulp, etc.), pulp obtained by chemical methods (craft pulp, sulfite pulp, etc.) Or the like. In order to improve the appearance of the cellulose-containing thermoplastic resin of the present invention or a molded product thereof, chemically bleached kraft pulp (N-BKP, L-BKP, etc.) is preferably used. Non-fibrillated fibrous cellulose may be used alone or in combination of two or more. The non-fibrillated fibrous cellulose may be a fiber subjected to a purification process such as a degreasing process (for example, absorbent cotton or the like). The non-fibrillated fibrous cellulose used in the present invention needs to be fibrous, that is, thread-like, not granular or powdery, and has an aspect ratio (length / diameter) larger than 5 and smaller than 500. preferable. More preferred is non-fibrillated fibrous cellulose having an aspect ratio (length / diameter) of greater than 10 and less than 500.

  In general, cellulose nanofibers are said to have a single fiber diameter smaller than 100 nm, but in order to obtain such nanofibers, it is not necessary to perform microfibrillation treatment with a high-pressure homogenizer or a millstone friction machine. Must not. Since it takes time to obtain cellulose nanofibers by microfibrillation treatment, energy is consumed greatly and the efficiency is poor. Even during melt-kneading, the cellulose fiber receives shearing force and impact force from the kneading apparatus. When a single fiber is subjected to the same shearing force, a fiber piece having a small fiber length and diameter has a larger shearing force per unit cell volume of cellulose, so that fine fibers are generally finer. Tend to be. Even in the case of cellulose nanofibers with a fiber diameter of less than 100 nm, which have been treated in advance, they are subjected to shearing force and impact force during melt-kneading, but the nanofibers and microfibril parts become finer and finer, and the aspect ratio ( The length / diameter) also decreases, and the strength of the molded body cannot be maintained. In addition, since the cellulose gradually disintegrates by self-decomposition from around 300 ° C. during melt-kneading, the fiber length further decreases with finer fibers. In any case, when fibrillated cellulose fibers are subjected to such melt-kneading, handling such as shearing force and impact force received during kneading and temperature control is difficult. On the other hand, the fibrous cellulose used in the present invention is not microfibrillated, and therefore the fiber diameter is larger than that of the microfibrillated cellulose, so that it is easy to handle and the strength of the molded product can be maintained.

  The thermoplastic resin in the present invention is a resin that can be softened by being heated to a glass transition temperature or a melting point and can be molded into a desired shape. For example, high-density polyethylene, medium-density polyethylene, Polyethylenes made of low density polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, polytetrafluoroethylene, acrylonitrile butadiene styrene resin, acrylonitrile styrene copolymer resin, acrylic resin, polyethylene terephthalate, polymethylene terephthalate, Examples thereof include polyester resins composed of polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and the like, but are not particularly limited as long as they are thermoplastic resins.

  Furthermore, a biodegradable resin can also be used as the thermoplastic resin. By using the biodegradable resin, it is expected that the molded product is decomposed by microorganisms by burying the molded product in the soil at the time of disposal. The biodegradable resin is not particularly limited as long as it is an environmentally decomposed resin, particularly a resin that is decomposed by the action of microorganisms. For example, specific examples include polymeric polysaccharides, microbial polyesters, aliphatic polyesters, and more specifically, polylactic acid resin, polycaprolactone resin, polybutylene succinate adipate resin, polyethylene succinate resin, polyethylene. Succinate carbonate resin, polybutylene succinate resin, polybutylene adipate terephthalate resin, polyhydroxyalkanoate (eg, poly (3-hydroxybutyric acid) (PHB), poly (3-hydroxyvaleric acid) (PHV)), lactone resin , Polyester resins obtained from low molecular weight aliphatic dicarboxylic acids and low molecular weight aliphatic diols, cellulose acetate-based composites, modified starch-modified polyvinyl alcohol composites, and other composites. If resin But it is not limited to.

  When a biodegradable resin is used as the thermoplastic resin of the present invention, it is preferable to use a polylactic acid resin because of its versatility. The polylactic acid resin includes a lactic acid-based polymer such as a lactic acid copolymer and a blend polymer in addition to a polylactic acid homopolymer. The mass average molecular weight of the lactic acid polymer is generally 5 to 500,000. Further, the constituent molar ratio L / D of the L-lactic acid unit and the D-lactic acid unit in the polylactic acid resin may be any of 100/0 to 0/100, and is not particularly limited.

  In the present invention, when the non-fibrillated fibrous cellulose and the thermoplastic resin are charged into the stirring chamber of the batch type closed kneading apparatus, the moisture content of the fibrous cellulose is preferably 30 to 90% by mass, 30 -80 mass% is more preferable, and 35-70 mass% is further more preferable. The water content in the present invention refers to a numerical value obtained by dividing the absolute dry rate obtained by an operation method according to JIS P8203 from 100% by mass with a drying temperature of 120 ° C. ± 2 ° C. When the water content of the non-fibrillated fibrous cellulose is within the above range, the affinity between the non-fibrillated fibrous cellulose and the thermoplastic resin is increased, and the dispersibility of the non-fibrillated fibrous cellulose in the thermoplastic resin matrix is increased. As a result, the uniformity of the cellulose-containing thermoplastic resin of the present invention is improved, and as a result, the strength of the molded body is further improved.

  The produced pulp is in a slurry (suspension) state and generally has a moisture content of 94 to 97% by mass. Moreover, the moisture content of the wet pulp sheet obtained by dehydrating the pulp slurry is generally 30 to 45% by mass, and the moisture content of the dried and dried pulp sheet is 15 to 20% by mass. Therefore, in the present invention, the wet pulp sheet can be used as it is, but in other forms, it is difficult to use it as it is as non-fibrillated fibrous cellulose having an appropriate water content.

  Therefore, in the present invention, it is also possible to use fibrous cellulose in a slurry state by separating the wet pulp sheet or the dry pulp sheet. For disaggregation, devices such as a pulper, a holender, a refiner, a kneader, and an edge liner can be used.

  The batch type closed kneading apparatus used in the present invention refers to a batch type high speed stirring apparatus described in pamphlet of International Publication No. 2004/076044 manufactured by M & F Technology. FIG. 1 is a schematic view of a batch type closed kneading apparatus used in the present invention. In the batch type closed kneading apparatus 1 used in the present invention, a cylindrical stirring chamber 3 is formed laterally on the machine base 2, and a material supply chamber 13 in which a material charging unit 14 and a spiral blade member 12 are disposed. Are arranged by a plurality of legs. A rotary shaft 5 is horizontally supported by bearings 4, 4 arranged at the leg portions at both ends, and the rotary shaft 5 is coaxially inserted into the center of the stirring chamber 3.

  As shown in FIG. 2, the outer periphery of the rotating shaft 5 disposed through the stirring chamber 3 has a total of six cross-sectional rectangles and rotary blades 10 a to 10 f having an overall shape rectangle. The rotating shaft 5 is provided so as to be opposed to each other in the axial direction at an angular interval of 180 degrees in the circumferential direction. When the rotary blades 10a and 10f at both ends in the axial direction rotate clockwise when viewed from the right side of FIG. 1, the leading edges of the rotary blades 10a and 10f are the inner surfaces of the vertical walls 11 and 11 at both ends of the stirring chamber 3. It is fixed to the outer periphery of the rotating shaft 5 so as to be in sliding contact with almost no gap. Further, the four rotating blades 10b, 10c, 10d, and 10e in the middle portion are fixed in a zigzag manner on the outer peripheral surface of the rotating shaft 5, and are arranged in directions in which the leading edges during rotation face both ends of the stirring chamber 3. ing.

  The motor side of the vertical walls 11 at both ends of the stirring chamber 3 is a material supply port of the stirring chamber 3 provided in one end wall of the stirring chamber 3, and 12 is a spiral material formed on the outer periphery of the rotating shaft 5. A supply blade member, 13 is a material supply chamber surrounding the supply screw, 14 is a material input portion provided above the material supply chamber 13, and the material input portion 14 is melted and kneaded after supplying the material. An openable and closable shutter 15 is sometimes provided that can maintain hermeticity at times.

  In the batch type closed kneading apparatus used in the present invention, a water vapor release mechanism 20 is provided at both ends of the rotary shaft 5. FIG. 3 is an enlarged schematic view of the water vapor release mechanism 20. A spiral groove 22 is cut in the portion of the rotating shaft that constitutes the water vapor release mechanism, and when the rotating shaft 5 rotates, a right screw or so that air is sent from the outside into the stirring chamber, or A spiral groove 22 is cut in the direction of the left screw. In FIG. 3, an arrow 24 indicates the direction of air sent from the outside into the stirring chamber. In the present invention, since the inside of the stirring chamber is in a very high pressure state during melt kneading, the high-pressure steam in the stirring chamber tends to leak outward in the direction of the arrow 23. However, in the water vapor release mechanism portion 20, the distance between the outermost peripheral portion of the spiral groove 22 cut in the rotating shaft 5 and the outer wall portion is very small. It comes to keep balance. Specifically, the distance between the outermost peripheral portion of the spiral groove 22 and the outer wall is 50 to 3000 μm, more preferably 50 to 700 μm, and further preferably 50 to 500 μm.

  The rotating shaft 5 on which the rotating blades are arranged is connected to a motor 8 that is a driving source. In the batch type closed kneading apparatus used in the present invention, a torque meter that measures the rotational torque applied to the motor 8 is installed. The control panel 21 can monitor the rotational torque. In the method for producing a cellulose-containing thermoplastic resin of the present invention, the change in the rotational torque of the rotary shaft 5 provided with the rotary blades 10a to 10f measured from the torque meter is measured to determine the end point of the melt-kneading. To do. Measures for the end operation according to the measured value of rotational torque are indispensable for materials handled for the first time, but when using the same material constantly, it is not always necessary to measure each time. It may be determined and the end point may be determined based on the determined melt-kneading time.

  Since the temperature in the stirring chamber rises rapidly due to the high shear force applied to the non-fibrillated fibrous cellulose and the thermoplastic resin from the rotating rotating blade, it can be adjusted by the rotational speed of the rotating blade. Therefore, if the temperature in the stirring chamber is to be close to 500 ° C., the rotating blades must be rotated at a considerably high speed. The rotational speed of the rotary blade is preferably 5 to 100 m / second, more preferably 7 to 50 m / second.

  The procedure of the method for producing the cellulose-containing thermoplastic resin of the present invention will be described. Non-fibrillated fibrous cellulose, thermoplastic resin, and water as required are charged into the stirring chamber 3 of the batch type closed kneader. Each material to be charged may be premixed with a blender or the like before being charged, or may be sequentially charged into the stirring chamber 3. When directly putting each material into the agitating chamber 3 without premixing, it is preferable to add them while stirring at low speed by the rotary blades 10a to 10f inside the agitating chamber 3. After each material is put into the stirring chamber 3, the stirring chamber 3 is sealed, and the rotary blades 10a to 10f are rotated at high speed. Each material is subjected to a strong impact or shearing force, and the temperature inside the stirring chamber 3 rapidly rises. As the temperature rises, the water inside the stirring chamber 3 including the water contained in the non-fibrillated fibrous cellulose evaporates to form water vapor, and the inside of the stirring chamber 3 is filled with water vapor, so that the internal pressure rises rapidly. Furthermore, when the temperature inside the stirring chamber 3 exceeds the softening temperature and melting temperature of the thermoplastic resin, the thermoplastic resin starts to soften or melt and starts to melt and mix with the non-fibrillated fibrous cellulose.

  In the method for producing a cellulose-containing thermoplastic resin of the present invention, by measuring the rotational torque of the rotating shaft 5 provided with the rotary blades 10a to 10f, the progress of the melt kneading is grasped, and the end of the melt kneading is completed. Can be determined. That is, specifically, the rotational torque increases as the rotational speed of the rotating blades increases. However, as the temperature of the material to be kneaded increases, the thermoplastic resin starts to melt, so that the thermoplastic resin is completely The rotational torque continues to decrease until it melts. Thereafter, melt kneading of the cellulose and the thermoplastic resin starts, and the rotational force starts to increase again as the interaction force at the interface between the cellulose and the resin increases. In the present invention, the rotation of the rotary blades may be terminated immediately after the rotational torque starts to rise again. In the present invention, the temperature of the material to be kneaded continues to rise while the rotational torque fluctuates from rising to lowering to rising, but melt kneading is performed at the thermal decomposition temperature of the material to be kneaded after the rotational torque is increased again. It is preferable to end before reaching. In particular, in cellulose, the thermal decomposition rate rapidly increases at around 400 ° C., so it is preferable to end the melt-kneading at 370 ° C. or lower. That is, in the present invention, an arbitrary time until the temperature of the material to be kneaded reaches 370 ° C. can be set immediately after the rotational torque starts to increase.

  At the time of melt-kneading, a material to be kneaded made of non-fibrillated fibrous cellulose and a thermoplastic resin needs to be protected from oxidative decomposition. In particular, suppression of oxidation by oxygen is important for suppressing changes in the structural properties of the material to be kneaded. Therefore, in the method for producing a cellulose-containing thermoplastic resin of the present invention, in the water vapor release mechanism, the water vapor inflow / outflow balance is maintained, that is, the water flowing out from the stirring chamber and the water flowing from the outside into the stirring chamber. It is preferable to prevent the inflow of air into the stirring chamber by maintaining a balanced equilibrium state with the air to be released. In the production method of the present invention, immediately after the start of stirring, the pressure in the stirring chamber rapidly increases, and at that time, in the steam release mechanism, the inflow and outflow of water vapor are not in a balanced state, The water vapor flows out from the release mechanism. During this time, the pressure in the stirring chamber shows a decreasing tendency, finally reaches an equilibrium state, and maintains a constant pressure. In the production method of the present invention, the inside of the stirring chamber may be in a subcritical state of water. The subcritical state of water means a state lower than the supercritical point of water (temperature: 375 ° C., pressure: 22 MPa), and subcritical water is very oxidizable. Since cellulose is slowly decomposed by a hydration reaction even in the subcritical state of water at 300 ° C. and around 20 MPa, the reaction time is also important. In consideration of the above, in the manufacturing method of the present invention, with the internal pressure of the stirring chamber held by steam of about 2 to 10 MPa, immediately after the rotational torque shows the minimum value, that is, the minimum value is shown. From at least 1 second to 10 minutes, preferably from 1 second to 2 minutes, more preferably from 1 second to 30 seconds, and it is necessary to carry out melt kneading while preventing the inflow of oxygen and protecting the cellulose and the thermoplastic resin from oxygen oxidation. is there.

  In the present invention, various additives can be appropriately added in addition to the non-fibrillated fibrous cellulose and the thermoplastic resin. Additives include compatibilizers, antioxidants, heat stabilizers, lubricants, mold release agents, plasticizers, UV absorbers, light stabilizers, pigments, dyes, antistatic agents, conductivity-imparting agents, dispersants, Additives such as transparent nucleating agents, antibacterial agents, antifungal agents, and flame retardants can be used alone or in combination of two or more, but are not limited thereto. In particular, the addition of an organic antioxidant, an organic ultraviolet absorber, an antistatic agent, and a flame retardant is preferable because the use of the cellulose-containing thermoplastic resin of the present invention is expanded. Examples of organic antioxidants include phenolic, hindered phenolic, thioether and phosphite types.

  In the present invention, it is preferable to add an acid-modified polyolefin resin because the affinity between the non-fibrillated fibrous cellulose and the thermoplastic resin is improved and the adhesiveness between the two is strengthened. The acid-modified polyolefin resin refers to a resin obtained by modifying a polyethylene resin or a polypropylene resin with at least one selected from unsaturated carboxylic acids and derivatives (monomers) thereof. Examples of unsaturated carboxylic acids and / or derivatives thereof include unsaturated carboxylic acids such as acrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, and derivatives thereof, such as, specifically, anhydrides, amides, imides And esters. Among these, maleic anhydride-modified polyolefin is particularly preferable. The amount of maleic anhydride-modified polyolefin added to the cellulose-containing thermoplastic resin is preferably from 0.1 to 10% by mass, more preferably from 1 to 7% by mass, and more preferably from 2 to 5% by mass, based on the content of the cellulose-containing thermoplastic resin. Is more preferable.

  In the present invention, the mass ratio between the non-fibrillated fibrous cellulose and the thermoplastic resin is preferably 10/90 to 70/30, more preferably 20/80 to 60/40, and 40/60 to 60/40. Is more preferable. When the mass ratio between the non-fibrillated fibrous cellulose and the thermoplastic resin is within this range, the cellulose-containing thermoplastic resin taken out from the stirring chamber after the reaction is a flake-like piece, and in the molding step which is the next step Handling becomes easy. Further, if the mass ratio of non-fibrillated fibrous cellulose and thermoplastic resin is within this range, the amount of combustion heat generated when the molded product made of the cellulose-containing thermoplastic resin of the present invention is incinerated can be reduced.

  When the mass ratio between the non-fibrillated fibrous cellulose and the thermoplastic resin is out of the above range, the cellulose-containing thermoplastic resin taken out from the stirring chamber may contain a lump of flake-shaped pieces. However, in that case, it is preferable to grind with a grinder. The pulverizer is not particularly limited, but is preferably a pulverizer that is less contaminated with foreign matter and does not generate much heat. For example, specifically, an airflow pulverizer, a cutter pulverizer, and the like can be given.

  Using the cellulose-containing thermoplastic resin of the present invention, a molded product can be produced by various molding methods. As a molding method, a general molding method can be used and is not particularly limited. Specific examples include injection molding, extrusion molding, compression molding, rotational molding, hollow molding (blow molding), T-die molding, inflation molding, calendar molding, and the like. Yes, but you are not limited to these methods. Further, the shape of the molded body is not particularly limited, and any shape may be produced by any molding method.

  In order to realize the excellent moldability of the cellulose-containing thermoplastic resin of the present invention, it is preferable to obtain a molded body having a precise shape using an injection molding method. The cellulose-containing thermoplastic resin of the present invention generates molding defects such as flow marks, weld lines, warpage, and twisting, as well as good fluidity of the resin at the time of molding. There is nothing to do.

  Moreover, as a molding method of the cellulose-containing thermoplastic resin of the present invention, an extrusion molding method is also preferably used. By using the cellulose-containing thermoplastic resin of the present invention, a deformed shape using a core is possible, and sheet molding is also possible. Furthermore, in the case of sheet forming, after forming, uniaxial stretching and biaxial stretching treatment can be performed to improve sheet strength.

  Furthermore, in the thermoplastic resin of the present invention, fibrous cellulose is very uniformly dispersed in the thermoplastic resin, so that the kneading time when the molded body once molded is pulverized again and melt-molded is short. Tesumu. Therefore, since the fibrous cellulose contained therein is less damaged by heat, it can be reused as a molding material.

  EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to these at all.

Example 1
After preparing a wet pulp sheet of hardwood bleached kraft pulp (L-BKP) as non-fibrillated fibrous cellulose, preparing so that the solid content concentration is 25% by mass, throwing it into a disaggregator and disaggregating, Dehydrated to produce non-fibrillated fibrous cellulose having a water content of 60% by mass. Non-fibrillated fibrous cellulose and thermoplastic resin (manufactured by Prime Polymer Co., Ltd., trade name: Prime Polypro (registered trademark) F109V) were prepared so as to have a mass ratio of 50:50. (M & F Technology Co., Ltd.) was added to the stirring chamber. Thereafter, the rotating blades were rotated at a rotational speed of 1500 rpm (corresponding to 26 m / sec at the peripheral speed at the tip of the rotating blades). As soon as rotation started, water vapor started to leak from the release mechanism. Approximately 5 minutes later, after the rotational torque value of the motor reached the maximum value, it began to decrease, and after 20 seconds after the minimum value was shown and started to increase, the motor was switched off and the rotation of the rotating blades was stopped. During this time, water vapor leaked from the release mechanism, and the internal pressure of the stirring chamber did not maintain a constant value and showed a decreasing tendency. The temperature in the stirring chamber when the motor was turned off was 380 ° C. After the rotation of the rotating blade was completely stopped, the cellulose-containing thermoplastic resin of the present invention was taken out. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 2)
As a non-fibrillated fibrous cellulose, a hard pulp bleached kraft pulp (L-BKP) wet pulp sheet was prepared and pulverized with a cutter type pulverizer (product name: BO-2572, 4 mm mesh mounted). Then, it was finely pulverized with a cutter type pulverizer (trade name: Mesh Mill HA8-2542-25 manufactured by Horai Co., Ltd.) to obtain non-fibrillated fibrous cellulose. A non-fibrillated fibrous cellulose and a thermoplastic resin (manufactured by Prime Polymer Co., Ltd., trade name: Prime Polypro (registered trademark) F109V) were prepared at a mass ratio of 50:50, and after premixing, Then, water corresponding to a water content of non-fibrillated fibrous cellulose of 60% by mass was added and premixed, and then charged into the same batch type closed kneader used in Example 1. Thereafter, in the same manner as in Example 1, the cellulose-containing thermoplastic resin of the present invention was obtained. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 3)
In Example 2, the number of revolutions was changed to 2500 rpm (equivalent to 43 m / sec at the peripheral speed of the tip of the rotating blade) to obtain the cellulose-containing thermoplastic resin of the present invention. At the same time as the rotation of the rotating blades started, the water vapor began to leak from the release mechanism, but after 1 minute, the leakage stopped and the melt kneading proceeded in a state where the balance was maintained at the release mechanism. One minute after the leakage of water vapor stops, the motor torque reaches the maximum value and then starts to decrease. After 20 seconds from the start of the minimum value, the motor is switched off and the rotor blades are turned off. Stopped rotating. It should be noted that the pressure in the stirring chamber had a constant value from the stop of the leakage of water vapor to the stop of stirring of the rotary blades. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-like piece as a whole, and a lump in which the piece was hardened was not found therein.

Example 4
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 3 except that the non-fibrillated fibrous cellulose was changed to a wet pulp sheet of softwood bleached kraft pulp (N-BKP). The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 5)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 3 except that the non-fibrillated fibrous cellulose was changed to a wet pulp sheet of hardwood chemiground pulp (CGP). The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 6)
The blended composition in the batch type closed kneading apparatus was mixed with non-fibrillated fibrous cellulose / thermoplastic resin / maleic anhydride-modified polypropylene (Mitsubishi Chemical Corporation, trade name: Modic (registered trademark) P928) = 50/45 / A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 3 except that it was changed to 5. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 7)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 3 except that the water content of the non-fibrillated fibrous cellulose was changed to 28% by mass. Leakage of water vapor from the release mechanism stopped 30 seconds after the start of stirring. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 8)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 3 except that the water content of the non-fibrillated fibrous cellulose was changed to 30% by mass. Leakage of water vapor from the release mechanism stopped 30 seconds after the start of stirring. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

Example 9
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 3 except that the water content of the non-fibrillated fibrous cellulose was changed to 90% by mass. The leakage of water vapor from the release mechanism stopped 3 minutes after the start of stirring. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 10)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 3 except that the water content of the non-fibrillated fibrous cellulose was changed to 95% by mass. The leakage of water vapor from the release mechanism stopped 3 minutes after the start of stirring. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 11)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 3 except that non-fibrillated fibrous cellulose and a thermoplastic resin were prepared to have a mass ratio of 7:93. In addition, although the obtained cellulose containing thermoplastic resin of this invention was a flake-like small piece as a whole, the lump which the small piece hardened in part was seen.

(Example 12)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 3 except that non-fibrillated fibrous cellulose and a thermoplastic resin were prepared so as to have a mass ratio of 10:90. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 13)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 3 except that non-fibrillated fibrous cellulose and a thermoplastic resin were prepared so as to have a mass ratio of 70:30. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 14)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 3 except that non-fibrillated fibrous cellulose and a thermoplastic resin were prepared so as to have a mass ratio of 74:26. In addition, although the obtained cellulose containing thermoplastic resin of this invention was a flake-like small piece as a whole, the lump which the small piece hardened in part was seen.

(Example 15)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 7 except that non-fibrillated fibrous cellulose and thermoplastic resin were prepared so as to have a mass ratio of 7:93. In addition, although the obtained cellulose containing thermoplastic resin of this invention was a flake-like small piece as a whole, the lump which the small piece hardened in part was seen.

(Example 16)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 7 except that non-fibrillated fibrous cellulose and thermoplastic resin were prepared so as to have a mass ratio of 10:90. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 17)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 7 except that non-fibrillated fibrous cellulose and thermoplastic resin were prepared so as to have a mass ratio of 70:30. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 18)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 7 except that non-fibrillated fibrous cellulose and a thermoplastic resin were prepared so as to have a mass ratio of 74:26. In addition, although the obtained cellulose containing thermoplastic resin of this invention was a flake-like small piece as a whole, the lump which the small piece hardened in part was seen.

(Example 19)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 8 except that non-fibrillated fibrous cellulose and a thermoplastic resin were prepared to have a mass ratio of 7:93. In addition, although the obtained cellulose containing thermoplastic resin of this invention was a flake-like small piece as a whole, the lump which the small piece hardened in part was seen.

(Example 20)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 8 except that non-fibrillated fibrous cellulose and a thermoplastic resin were prepared so as to have a mass ratio of 10:90. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 21)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 8 except that non-fibrillated fibrous cellulose and a thermoplastic resin were prepared so as to have a mass ratio of 70:30. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 22)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 8 except that non-fibrillated fibrous cellulose and a thermoplastic resin were prepared so as to have a mass ratio of 74:26. In addition, although the obtained cellulose containing thermoplastic resin of this invention was a flake-like small piece as a whole, the lump which the small piece hardened in part was seen.

(Example 23)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 9 except that non-fibrillated fibrous cellulose and a thermoplastic resin were prepared to have a mass ratio of 7:93. In addition, although the obtained cellulose containing thermoplastic resin of this invention was a flake-like small piece as a whole, the lump which the small piece hardened in part was seen.

(Example 24)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 9 except that non-fibrillated fibrous cellulose and a thermoplastic resin were prepared so as to have a mass ratio of 10:90. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 25)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 9 except that non-fibrillated fibrous cellulose and a thermoplastic resin were prepared so as to have a mass ratio of 70:30. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 26)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 9 except that non-fibrillated fibrous cellulose and a thermoplastic resin were prepared so as to have a mass ratio of 74:26. In addition, although the obtained cellulose containing thermoplastic resin of this invention was a flake-like small piece as a whole, the lump which the small piece hardened in part was seen.

(Example 27)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 10 except that non-fibrillated fibrous cellulose and a thermoplastic resin were prepared so as to have a mass ratio of 7:93. In addition, although the obtained cellulose containing thermoplastic resin of this invention was a flake-like small piece as a whole, the lump which the small piece hardened in part was seen.

(Example 28)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 10 except that non-fibrillated fibrous cellulose and thermoplastic resin were prepared so as to have a mass ratio of 10:90. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 29)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 10 except that non-fibrillated fibrous cellulose and a thermoplastic resin were prepared so as to have a mass ratio of 70:30. The obtained cellulose-containing thermoplastic resin of the present invention was a flake-shaped piece as a whole, and a lump in which the piece was hardened was not found therein.

(Example 30)
A cellulose-containing thermoplastic resin of the present invention was obtained in the same manner as in Example 10 except that non-fibrillated fibrous cellulose and thermoplastic resin were prepared so as to have a mass ratio of 74:26. In addition, although the obtained cellulose containing thermoplastic resin of this invention was a flake-like small piece as a whole, the lump which the small piece hardened in part was seen.

(Comparative Example 1)
A cellulose-containing thermoplastic resin was obtained in the same manner as in Example 2 except that the batch type closed kneading apparatus was changed to a Henschel mixer (registered trademark). The steam leaks from the Henschel mixer (registered trademark) at the same time as the rotation of the rotating blades, and the steam continues to leak during the melt-kneading operation. At this time, the pressure in the stirring chamber is 0.1 MPa, which is normal pressure. showed that.

(Comparative Example 2)
A cellulose-containing thermoplastic resin was obtained in the same manner as in Example 3 except that the melt torque kneading was terminated immediately before the rotational torque showed the maximum value and then decreased and reached the minimum value.

(Comparative Example 3)
A cellulose-containing thermoplastic resin was obtained in the same manner as in Example 3 except that the melt-kneading was terminated 20 minutes after the rotational torque showed the minimum value. The temperature in the stirring chamber immediately before the completion of melt kneading was 480 ° C.

(Comparative Example 4)
A cellulose-containing thermoplastic resin was obtained in the same manner as in Example 3 except that the melt-kneading was terminated when the rotational torque began to decrease after reaching the maximum value.

(Comparative Example 5)
A cellulose-containing thermoplastic resin was obtained in the same manner as in Example 3 except that the melt torque kneading was terminated when the rotational torque started to decrease after reaching the maximum value and reached 50% of the maximum value.

(Precision moldability)
The better the dimensional accuracy, the less the deformation and the like when forming a finer shape, and the better the precision moldability. Therefore, the lateral / aspect ratio (anisotropy) of the linear expansion coefficient was used as a measure of dimensional accuracy, that is, precision moldability. The smaller the value, the better the precision moldability. The measurement was performed according to ASTM D696 (temperature increase rate: 2 ° C./min, temperature range: 23-80 ° C., measuring instrument: manufactured by Perkin Elmer Japan, trade name: DMA7).

(warp)
A plate (150 mm × 80 mm × 1 mm) was injection molded using an injection molding machine (manufactured by Nippon Steel Works, Ltd., trade name: J55ELIII) using the cellulose-containing thermoplastic resin produced in the examples and comparative examples. During molding, the injection time was set to 0.3 seconds. The prepared plate was placed on a flat table and the lift amount was measured. In the measurement, when one of the four corners was brought into close contact with the table, the amount of lifting at the corner having the highest lifting amount was measured. Smaller lift is better and it is judged that there is little warpage because the resin characteristics are uniform.

(Flexural modulus)
The bending elastic modulus was measured according to JIS K7171 using the cellulose-containing thermoplastic resins prepared in Examples and Comparative Examples. The larger the value, the higher the flexural modulus.

(Appearance)
The cellulose-containing thermoplastic resins obtained in Examples and Comparative Examples were dried in a dryer set at 90 ° C. for 3 hours, and then 2 mm thick with an injection molding machine (trade name: J55ELIII, manufactured by Nippon Steel Works). Twenty plates (80 mm × 50 mm) were molded, the appearance was visually evaluated, and the evaluation result was the number of sheets with good appearance without flow marks and surface roughness. Larger numbers are better.

(Extrudability)
Using the cellulose-containing thermoplastic resin produced in the examples and comparative examples, a deformed shape was formed using an extrusion molding machine (a deformed shape device manufactured by IK Corporation, mold shape: 150 mm × 5 mm). The finished molded product is cut to a length of 200 mm, and it is confirmed whether the molded product is warped or twisted on a flat plane. Those having good extrudability do not bend by their own weight or are not rounded when extruded from the mold, so that no warping or twisting occurs. The case where there was no warp, twist, etc. was marked with ○, and the case where even slight occurrence was marked with ×.

  The evaluation results are shown in Table 1.

  As is clear from Table 1, the Examples are superior to the Comparative Examples in all evaluation items of precision moldability, warpage, flexural modulus, appearance, and extrusion moldability. In particular, since the precision of formability and the flexural modulus of the cellulose-containing thermoplastic resin of the present invention prepared in the examples are superior to the cellulose-containing thermoplastic resin prepared in the comparative example, the cellulose-containing heat of the present invention. In the plastic resin, it can be seen that the fibrous cellulose is uniformly dispersed in the thermoplastic resin matrix, and that the affinity between the two is good.

  Examples 7, 8, 9, and 10 (non-fibrillated fibrous cellulose / thermoplastic resin = 50/50) and Examples 11, 15, 19, and 23 having the same ratio of fibrous cellulose / thermoplastic resin 27 (non-fibrillated fibrous cellulose / thermoplastic resin = 7/93) and Examples 12, 16, 20, 24, 28 (non-fibrillated fibrous cellulose / thermoplastic resin = 10/90) and Example 13 17, 21, 25, 29 (non-fibrillated fibrous cellulose / thermoplastic resin = 70/30) and Examples 14, 18, 22, 26, 30 (non-fibrillated fibrous cellulose / thermoplastic resin = 74 / In each combination of 26), when the flexural modulus is compared, it can be seen that the flexural modulus is further improved when the moisture content of the fibrous cellulose is in the range of 30 to 90% by mass.

  In Examples, when the ratio of fibrous cellulose / thermoplastic resin is less than 10/90, there is a tendency that the precision moldability tends to increase slightly, and when there is more fibrous cellulose than 70/30, It can be seen that the flexural modulus tends to decrease slightly. In the case where the ratio of fibrous cellulose / thermoplastic resin is in the range of 10/90 to 70/30, no lump of solidified pieces was generated in the obtained cellulose-containing thermoplastic resin. When the ratio is out of this range, a small mass of small pieces is generated. The lump was not so large as to be a major obstacle in the subsequent molding step, but it is preferable that the lump does not occur. Therefore, in this invention, it turns out that 10 / 90-70 / 30 is more preferable as a ratio of fibrous cellulose and a thermoplastic resin.

  Since the thermoplastic resin produced by using the method for producing a cellulose-containing thermoplastic resin of the present invention has more uniform characteristics, it is possible to obtain a precise molded article such as a thin molded article. In addition, since the characteristics are uniform, it can exhibit excellent characteristics as a whole, and can be used after being pulverized and melt-molded as a molding material again. .

DESCRIPTION OF SYMBOLS 1 High-speed stirring apparatus 2 Machine base 3 Stirring chamber 4 Bearing 5 Rotating shaft 8 Motor 10a-10f Rotary blade 11 Vertical wall 12 of stirring chamber Spiral blade member 13 Material supply chamber 14 Material input part 15 Shutter 20 Steam release mechanism 21 Control panel 22 Spiral groove 23 Water vapor outflow direction 24 Air inflow direction

Claims (6)

  Cellulose-containing thermoplastic resin in which at least a thermoplastic resin and non-fibrillated fibrous cellulose are melt-kneaded by high-speed rotation of a rotary blade disposed on a rotary shaft in a stirring chamber provided in a batch type closed kneading apparatus. In this production method, the batch-type closed kneading apparatus has a water vapor release mechanism for releasing an excess of water vapor generated from the non-fibrillated fibrous cellulose in the stirring chamber to the outside, and A process for producing a cellulose-containing thermoplastic resin, characterized in that melt kneading is terminated and a material to be kneaded is taken out immediately after the rotational torque of the rotating shaft provided with the rotating blades reaches a minimum value and starts to rise.   The method for producing a cellulose-containing thermoplastic resin according to claim 1, wherein the water content of the non-fibrillated fibrous cellulose is 30 to 90% by mass.   The method for producing a cellulose-containing thermoplastic resin according to claim 1, wherein the mass ratio of the non-fibrillated fibrous cellulose and the thermoplastic resin in a dry state is 10/90 to 70/30.   A cellulose-containing thermoplastic resin produced by the method for producing a cellulose-containing thermoplastic resin according to claim 1.   A cellulose-containing thermoplastic resin molded article obtained by injection molding the cellulose-containing thermoplastic resin according to claim 4.   A cellulose-containing thermoplastic resin molded article obtained by extrusion-molding the cellulose-containing thermoplastic resin according to claim 4.

Images