JP2019199009A - Manufacturing method of bamboo powder composite resin, manufacturing method of bamboo powder resin mixed melt, bamboo powder resin mixed melt, and bamboo powder composite resin - Google Patents

Abstract

To provide a bamboo powder composite resin having a porous interior and high percentage content of a bamboo powder having large particle size and a high moisture content, and a manufacturing method of the same, and to enlarge a range of new composite resin that can be manufactured, and to provide a molded body having good strength characteristics and remoldable.SOLUTION: In a manufacturing method of a bamboo powder composite resin, the bamboo powder composite resin is manufactured by melting and mixing a resin powder and a bamboo powder as raw material by rotating a rotating shaft in an agitating chamber of a closed mixing and grinding device having the rotating shaft provided with a plurality of rotating blades. The bamboo powder is pulverized to an average particle size of 1 μm or more to 800 μm or less, and has a moisture content of 5 to 40% by mass. Immediately after a temperature in the agitating chamber at a time of melt mixing is 150°C or higher and 370°C or lower, a pressure is 0.20 MPa or higher and saturated water vapor or lower, and a rotational torque of the rotating shaft decreases to reach a minimum value and further increases, rotation is stopped.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a method for producing a bamboo powder composite resin, a method for producing a bamboo powder resin mixed melt, a bamboo powder resin mixed melt, and a bamboo powder composite resin. Specifically, the present invention relates to a method for producing a bamboo powder composite resin in which porous fine bamboo powder is combined with a resin by high temperature and high pressure melting, a method for producing a bamboo powder resin mixed melt, a bamboo powder resin mixed melt, and a bamboo powder composite resin.

Cellulose-based composite resins in which woody biomass is combined with a resin include a wood deck or the like commonly referred to as wood plastic. This uses recycled wood and recycled plastics as raw materials with the goal of an inexpensive manufacturing method. In order to combine wood powder with plastic, it has been considered that the wood powder is fine and does not contain moisture, for example, an average particle size of 10 μm or less and a moisture content of 5% or less when viewed from the plastic side. That is, if the particle size is large and there is a lot of moisture, the wood powder does not mix well in the plastic. As a result, wood flour contained no more than 30-50%. Furthermore, in order to obtain a molded body in which 30 to 50% of wood powder is combined, it has been limited to products having a simple shape molded by extrusion molding or press molding. Wood powder composite resin has the advantage of combining the goodness of looking like wood with the goodness of resin, but conversely there are weaknesses that are neither of them. In this way, there are problems in quality maintenance and productivity.
Recently, cellulose nanofiber (CNF) has been widely taken up with a technology that focuses on high strength, high elasticity, and low thermal expansion, but it is still far from practical use.

  Focusing on bamboo fibers, there have been several attempts to grind bamboo with water vapor, break it into threads, cut it into fine pieces, and combine it with resin, but nothing has been put into practical use. By simply kneading the resin at about 100 ° C. and mixing the bamboo powder with a conventional kneading apparatus using a resin manufacturing technique, the bamboo can be kneaded at a low purity and is not a melt-integrated composite resin. In addition, an attempt has been made to put an antibacterial filler in order to exert antibacterial properties from the original components of bamboo.

  On the other hand, bamboo is abundant in Japan, and if it can be mixed into plastic, it can be expected to become a fiber reinforcing agent. However, it is difficult to make fine particles with an average particle size of 400 μm or less, and the water content is large and 35% or less Because it was difficult, it was a big wall to be combined with plastic.

  By the way, the inventor invented a special bamboo powder manufacturing machine having a special milling tool, and used a bamboo having porous vascular bundle inside, a secondary pulverizer using an average particle size of 400 μm by primary pulverization as a raw material. We succeeded in producing bamboo powder with an average particle size of 50μ by secondary crushing. The milling tool cuts and crushes the end face of the bamboo, and is suitable for cutting and crushing the end face of the cylindrical workpiece (see Patent Documents 1 and 2).

In addition, when mixing and pulverizing the cellulosic material and the plastic binder using a mixing and pulverizing apparatus manufactured by M & F Technology Co., Ltd., the above material is mixed and pulverized in the mixing container, and heat is generated due to heat generated by shearing, friction and compression. Ingredients are dehydrated. Next, due to the collision energy at the time of mixing and pulverization, it finally becomes fine particles and a rapid temperature rise occurs. And unlike the simple mixing in the prior art, the inside of the mixing container is in a high temperature and high pressure state instantly. Next, the free water present in voids such as cell lumens and cell gaps, and the gap where the bound water contained in the cell walls has escaped, are lignin in the wood, followed by a large proportion of lignin. Plastic resin (polypropylene PP, polyethylene PE, biodegradable resin, etc.) enters and melts and integrates with cellulose, etc., which constitutes wood, which cannot be found by simple mixing, with a uniform and strong bonding force. In other words, lignin is a natural polymer with a three-dimensional network structure composed of three monoglycolic polymers, so that the dehydrated cellulose component is impregnated with the molten binder due to the affinity of the binder polymer. (See Patent Document 3). That is, when the above mixing and grinding apparatus is used, the cellulosic material and the plastic can be mixed and melted.
And the cellulose composite resin is manufactured about pulp and kenaf using this mixing and grinding apparatus (refer patent documents 4 and 5).

Japanese Patent No. 5344644 Utility Model Registration No. 3176586 Japanese Patent No. 4489017 JP 2011-116838 A Japanese Patent No. 5314867

Therefore, the inventor uses a technique for producing fine bamboo powder by a special bamboo powder production machine having a special milling tool, and mixing and melting a cellulosic material and a plastic using a mixing and pulverizing apparatus. As a result, the inventors have come up with the possibility of forming a reinforced plastic over the wall by using bamboo powder.
The present invention provides bamboo powder composite resin, bamboo powder resin mixed melt and bamboo powder resin mixed melt having a high content of cellulosic material using bamboo powder having a large particle size and a high water content, and a new method that can be produced. An object of the present invention is to expand the range of various composite resins and to provide a remoldable molded article having good strength characteristics.

  The method for producing a bamboo powder composite resin according to the first aspect of the present invention includes the steps of melting and mixing a resin powder and bamboo powder as raw materials in the stirring chamber 3 of the hermetic mixing and pulverizing apparatus 1 to obtain a bamboo powder resin mixed melt. This is a method for producing a bamboo powder composite resin, which is manufactured and molded into a bamboo powder resin mixed melt to produce a bamboo powder composite resin. In this manufacturing method, for example, as shown in FIG. 8, bamboo powder is bamboo powder having an average particle size of 1 μm or more and 800 μm or less (S001) and having a moisture content of 5 to 40% by mass. In S005), the temperature in the stirring chamber 3 is 150 ° C. or more and 370 ° C. or less, the pressure is 0.20 MPa or more and saturated steam or less, and the rotational torque of the rotating shaft 5 decreases to reach a minimum value, and further increases. (S007) Immediately after the rotation is stopped (S008), a bamboo powder resin mixed melt is produced (S009). After that, for example, as shown in FIG. 9, the bamboo powder resin mixed melt is pulverized (S011) and molded (S012) to produce a bamboo powder composite resin (S0013). Further, as shown in FIG. 4, the closed-type mixing and pulverizing apparatus 1 in which melt mixing is performed has a rotating shaft 5 in which a plurality of rotating blades 10 a to 10 f are disposed, and the bamboo powder composite resin is mixed in its stirring chamber. 3, resin powder and bamboo powder are used as raw materials, and the rotary shaft 5 is rotated and melt mixed.

Here, the bamboo powder composite resin refers to a mixture of bamboo powder and resin that is integrated and integrated, but here, what is mixed and melted at high temperature and high pressure is a bamboo powder resin mixed melt, then pulverized and molded This is called bamboo powder composite resin. In addition, those that are heated, cooled, processed, deformed after mixing and melting, and those that are mixed in other resins are also included in the bamboo powder resin mixed melt, and those that are heated, cooled, processed, deformed after molding, other The resin mixed with other resins is also included in the bamboo powder composite resin.
After stopping the rotation, it can be taken out as a bamboo powder resin mixed melt. Next, it is pulverized to a size that can be put into a molding machine and molded by a plastic molding machine to produce a bamboo powder composite resin. The bamboo powder resin mixed melt is melted again in the process of being molded by various molding machines to become a plastic product as a molded body. That is, by making the bamboo powder resin mixed melt taken out as a melt from the mixing and grinding device, unlike the conventional biomass kneading method, while combining the high proportion of biomass such as 70% or 60% bamboo powder, Molding with an injection molding machine that injects from the nozzle to the mold becomes possible, and bamboo powder composite resin is produced including other moldings. Further, “immediately after” refers to a short period of time after the minimum value is shown, and is preferably at least 1 second to 10 minutes, more preferably 1 second to 2 minutes, and even more preferably 1 second to 30 seconds.
When configured in this way, a bamboo powder composite resin having a porous vascular bundle of bamboo, a large particle size and a high moisture content, and a high content of cellulosic material is provided. The range of new composite resins that can be manufactured can be expanded.

The method for producing a bamboo powder composite resin according to the second aspect of the present invention is the same as the method for producing a bamboo powder composite resin according to the first aspect, as shown in FIGS. 1, 2A and 2B. A plurality of tip rows each having a plurality of tips 34 arranged radially and extending in the circumferential direction are provided on the end surface 35 of the tool body to which the tips 34 serving as blades are attached, and the tips of a pair of adjacent tip rows each have a rotation center axis. Is a fine powder pulverized by using a milling tool 32 arranged in a staggered manner with different radial distances from each other, and a porous structure of a bamboo vascular bundle is observed by an electron micrograph, 10 ³ to 10 ¹¹ / g of lactic acid bacteria grow, and the weight ratio of bamboo powder to resin is 5:95 to 95: 5.
If comprised in this way, the bamboo powder as a raw material suitable for manufacture of a bamboo powder composite resin can be provided.

The manufacturing method of the bamboo powder resin mixed melt in the third aspect of the present invention extracts the process of manufacturing the bamboo powder resin mixed melt as an intermediate from the manufacturing method of the bamboo powder composite resin in the first aspect. It is a thing.
If comprised in this way, the bamboo powder resin mixed melt as a material suitable for shaping | molding of a bamboo powder composite resin can be provided.

  The manufacturing method of the bamboo powder resin mixed melt in the fourth aspect of the present invention extracts the process of manufacturing the bamboo powder resin mixed melt as an intermediate from the manufacturing method of the bamboo powder composite resin in the second aspect. It is a thing.

  The bamboo powder resin mixed melt in the fifth aspect of the present invention is characterized by being manufactured by the method for manufacturing a bamboo powder resin mixed melt in the third or fourth aspect.

The bamboo powder composite resin according to the sixth aspect of the present invention is characterized by being manufactured by the method for producing a bamboo powder composite resin according to the first or second aspect.
When configured in this manner, bamboo powder having a large particle size and a high water content can be used to provide a bamboo powder composite resin having a high content of cellulosic material. The body can be provided.

  According to the present invention, bamboo powder having a large particle size and high moisture content, bamboo powder composite resin having a high content of cellulosic material, bamboo powder resin mixed melt, and methods for producing them can be provided. Thus, it is possible to expand the range of new composite resins that can be produced, and to provide a remoldable molded article having good strength characteristics.

It is a schematic diagram of the example of a special bamboo powder manufacturing machine. It is a schematic cross section of the example of the milling tool with which a special bamboo powder manufacturing machine is provided. It is a model front view of the example of the milling tool with which a special bamboo powder manufacturing machine is provided. It is an example of the electron micrograph of the bamboo powder manufactured with the special bamboo powder manufacturing machine. It is a schematic diagram of the example of a closed-type mixing and grinding apparatus. It is a schematic diagram of the example of the rotating shaft by which the some rotating blade was arrange | positioned. It is a schematic diagram of the example of the release mechanism of water vapor | steam. It is a figure which shows the example of the time change of rotational torque. It is a figure explaining the example of the procedure of the manufacturing method of a bamboo powder resin mixed melt. It is a figure explaining the example of the procedure of the manufacturing method from bamboo powder resin mixed melt to bamboo powder composite resin. It is an example of the electron micrograph of bamboo powder composite resin. It is a figure which shows the molded object which consists of bamboo powder composite resin.

  In the present embodiment, in a stirring chamber of a closed mixing and pulverizing apparatus having a rotating shaft provided with a plurality of rotating blades, the resin powder and bamboo powder are used as raw materials, and the rotating shaft is rotated and melt-mixed to obtain bamboo powder. The example of the manufacturing method of the bamboo powder composite resin which manufactures composite resin is demonstrated. Moreover, the example which uses the fine bamboo powder manufactured by the special bamboo powder manufacturing machine provided with a special milling tool as a raw material is demonstrated.

FIG. 1 shows a schematic diagram of an example of a special bamboo powder production machine used in the present invention.
The special bamboo powder production machine 31 used in the method for producing a bamboo powder composite resin of the present invention belongs to a dry bamboo powder production machine. Drop the branches and leaves of bamboo (bamboo material) W with an outer diameter of 8 cm or more, or Munetake bamboo or true bamboo, clean well, grasp the outer diameter of both ends, position, and end face 35 (33-33) of the mortar-shaped milling tool 32 at the right end 35 is arranged in a radial manner with a cutter 33 having carbide insert tips 34 disposed thereon, and rotated by a cutter driving unit 36 toward the cutter 33 without rotating the bamboo material W from the left end. Fine bamboo powder is made by cutting while feeding with a feed mechanism 37 (see Patent Documents 1 and 2). The bamboo material W is supported by the support means 38, is mounted on a slidable base 39, and moves toward the cutter 33. In addition, the bamboo powder in this invention is not restricted to this. Moreover, it will not be restrict | limited especially if it is the bamboo powder ground from raw bamboo. X is an axis of rotation center.

The schematic diagram of the example of the milling tool with which a special bamboo powder manufacturing machine is provided to FIG. 2A and FIG. 2B is shown. 2A is a cross-sectional view including a rotation center axis, and FIG. 2B is a front view.
The milling tool 32 includes a plurality of rows of milling cutters 33 each having a plurality of chips 34 radially arranged on an end surface 35 of a tool body to which chips 34 serving as cutting edges are attached, and extending in the circumferential direction. 33, the chips 34 of a pair of adjacent chip rows are arranged in a staggered manner with the radial distances from the rotation center axis alternately different. The bamboo powder used in the present invention is a fine powder pulverized using a milling tool 32, has a moisture content of 5 to 40% by mass, and a porous structure of the bamboo vascular bundle is observed by an electron micrograph. 10 ³ to 10 ¹¹ / g of lactic acid bacteria grows, and the weight ratio of the bamboo powder to the resin is 5:95 to 95: 5. Y is the moving direction of the bamboo material W, and Z is the rotating direction of the milling cutter.

FIG. 3 shows an example of an electron micrograph of bamboo powder manufactured by a special bamboo powder manufacturing machine.
Bamboo material W is a hollow cylindrical shape. Bamboo powder is produced by cutting a number of bamboo vascular bundles (water and nutrient paths) in the axial direction inside the bamboo basket at right angles to the axis. Is porous with a honeycomb shape of 20 μm inside.
Bamboo powder has a powder particle size of 1 to 800 μm, and the inside thereof is inhabited by about 10 ³ to 10 ⁴ lactic acid bacteria immediately after pulverization. This is sealed with a bag and allowed to lie for about 2 weeks to promote fermentation, and the number of lactic acid bacteria is increased to 10 ⁸ to 10 ¹¹ .

  The bamboo powder used in the present invention is preferably a porous fine bamboo powder obtained by pulverizing a bamboo basket excluding branches and leaves of natural bamboo powder with a special bamboo powder manufacturing machine. This bamboo powder has a high homogeneity in color and shape, so the hue becomes uniform when formed into a molded body, and even when the molded body is colored by mixing a master batch or pigment during molding Become.

  The bamboo powder used in the present invention is bamboo powder pulverized by a special bamboo powder manufacturing machine. Any powder may be used as long as it does not have a thread-like fiber that can be visually observed, and retains the porosity of the bamboo vascular bundle. The size of the bamboo powder is not particularly limited, but is preferably 400 μm or less, and more preferably 200 μm or less. Bamboo powder without porosity produced by other bamboo crushers (usually referred to as a chipper or a shredder) may deteriorate the physical strength and reduce the surface finish quality during resin molding.

The bamboo powder used in the present invention preferably has a water content of 5 to 30% by mass. When the moisture content of cellulose is in this range, the melt mixing time is shortened and the productivity is good. On the other hand, if the water content is less than 5% by mass, the pressure in the stirring chamber does not increase over time, so water may be replenished.
If the moisture content exceeds 35% by mass, it takes time to dehydrate the bamboo powder, so that the melting time becomes long and the bamboo powder may be easily decomposed. The moisture content is more preferably 8 to 35% by mass, and further preferably 10 to 25% by mass.

  FIG. 4 is a schematic view of an example of a closed type mixing and grinding apparatus 1 used in the present invention (see Patent Document 3). In the closed type mixing and pulverizing apparatus 1 used in the present invention, a plurality of material supply chambers 13 in which a cylindrical stirring chamber 3 and a material charging unit 14 and a spiral blade member 12 are disposed laterally on a machine base 2 are provided. Placed by the legs. The rotating shaft 5 is horizontally supported by the bearings 4 and 4 disposed at the leg portions at both ends, the rotating shaft 5 is coaxially inserted into the center of the stirring chamber 3, and one end of the rotating shaft is connected to the pulley 6 and the V. It is in rotational communication with a motor 8 as a drive source via a belt 7.

  FIG. 5 is a schematic diagram of an example of a rotating shaft provided with a plurality of rotating blades. On the outer periphery of the rotating shaft 5 disposed through the stirring chamber 3, for example, a total of six cross-sectionally-shaped rectangles and rotating blades 10 a to 10 f having an overall shape rectangle are arranged on the circumference of the rotating shaft 5. The projections are opposed to each other in the axial direction at a portion having an angular interval of 180 degrees in the direction. When the rotary blades 10a and 10f at both ends in the axial direction of the rotary blades rotate clockwise when viewed from the right side of FIG. 4, the leading edges thereof 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 8 side of the vertical wall 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 formed on the outer periphery of the rotating shaft 5. 13 is a material supply chamber surrounding the supply screw, 14 is a material input section provided above the material supply chamber 13, and after the material is input to the material input section 14, An openable and closable shutter 15 that can maintain hermeticity during melt mixing is provided.

  FIG. 6 is an enlarged schematic view of 20 examples of the water vapor release mechanism. The sealed mixing and grinding apparatus 1 used in the present invention is provided with a water vapor release mechanism 20 at both ends of the rotating shaft 5. A spiral groove 22 is cut in the portion of the rotating shaft that constitutes the water vapor release mechanism 20, and when the rotating shaft 5 rotates, a right-hand screw is used so that air is sent from the outside into the stirring chamber 3. Alternatively, a spiral groove 22 is cut in the direction of the left screw. The air inflow direction 24 (arrow) indicates the direction of air sent from the outside into the stirring chamber. In the present invention, since the inside of the stirring chamber 3 is in a very high pressure state at the time of melt mixing, the high-pressure steam in the stirring chamber tends to leak out toward the steam outflow direction 23 (arrow). However, in the water vapor release mechanism 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. Keep going.

  The rotary shaft 5 on which the rotary blades are arranged is connected to a motor 8 that is a drive source. In the closed mixing and grinding apparatus 1 used in the present invention, a torque meter (not shown) that measures the rotational torque applied to the motor 8 is used. ) Is installed, and the rotational torque can be monitored on the control panel 21 (see FIG. 4). In the method for producing a bamboo powder composite 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 mixing. .

FIG. 7 is a diagram illustrating an example of a temporal change in the rotational torque T. The rotational torque T applied to the main shaft of the motor 8 increases and reaches the maximum value M (time t _M ) according to the mixing and pulverization and drying state of the material in the closed mixing and pulverizing apparatus 1, and then decreases to the minimum value I. After a certain time t has elapsed after reaching (time t _I ), mixing and pulverizing from the take-out part 17 (see FIG. 4) of the hermetic mixing and pulverizing apparatus 1, dehydration, and impregnation with the bamboo powder and resin Remove the mixed melt. Measures for the end operation according to the measured value of the rotational torque are indispensable for materials that are handled for the first time, but when using the same material constantly, it is not always necessary to measure each time. The end point may be determined in advance by the determined melt mixing time.

  In the method for producing a bamboo powder composite resin in the present invention, the temperature and pressure conditions under which the bamboo powder and the resin are melted and mixed in the stirring chamber 3 of the hermetic mixing and pulverizing apparatus 1 are 150 to 370 ° C., 200 ˜370 ° C. is more preferred, 250 to 370 ° C. is more preferred, and the pressure range is 0.20 MPa to saturated water vapor pressure at the melt mixing temperature, and saturated water vapor pressure at 2.00 MPa to the melt mixing temperature is more preferred. In the present invention, it is more preferable that the melt mixing is performed in a subcritical state of water having a temperature or pressure slightly lower than the conditions of a temperature of 375 ° C. and a pressure of 22.00 MPa, which is a supercritical state of water.

  The saturated water vapor pressure in the present invention means that the water vapor pressure in the stirring chamber does not exceed the saturated water vapor pressure if the melt mixing temperature is constant during melt mixing and the internal volume of the stirring chamber does not change.

  FIG. 8 is a diagram for explaining an example of the procedure of the method for producing the bamboo powder resin mixed melt of the present invention. The prepared bamboo powder is cut and pulverized by the special bamboo powder manufacturing machine 31 to obtain a pulverized lactic acid fermentation fine powder (S001). Next, the bamboo powder and the resin are put into a closed type mixing and grinding device (S002). Bamboo powder and resin may be premixed with a blender or the like before being added, or may be sequentially added to the stirring chamber 3. When the bamboo powder and the resin are directly put into the stirring chamber 3 without preliminary mixing, it is preferable to put them while rotating the rotating blades 10a to 10f inside the stirring chamber 3 at a low speed. After the bamboo powder and the resin are put into the stirring chamber 3, the stirring chamber 3 is sealed, and the rotary blades 10a to 10f are rotated at high speed (S003). Bamboo powder and resin receive a strong shearing force, and the temperature inside the stirring chamber 3 rises rapidly. As the temperature rapidly rises, the water contained in the bamboo powder evaporates and turns into water vapor, and the inside of the stirring chamber 3 is filled with water vapor, causing the internal pressure to rise rapidly (S004). Further, when the temperature inside the stirring chamber 3 exceeds the softening temperature and melting temperature of the resin, the softening or melting of the resin starts, and the melt mixing of the bamboo powder and the resin starts (S005).

  In the method for producing a bamboo powder composite resin of the present invention, the rotational torque of the rotary shaft 5 provided with the rotary blades 10a to 10f is measured (S006), thereby grasping the progress of the melt mixing, Can determine the stop. That is, the rotational torque increases as the rotational speed of the rotary blades 10a to 10f increases. However, as the temperature of the material to be kneaded increases, thermal melting of the resin starts. It continues to decrease with the progress of thermal melting of the resin. At this time, the melt mixing of the bamboo powder and the resin has started, and the interaction force at the interface between the bamboo powder and the resin increases, so that the rotational torque once shows a minimum value and then reverses and starts to rise again. (S007). In the present invention, the rotation of the rotating shaft 5 is stopped immediately after the rotational torque starts to rise again (S008). In the present invention, the temperature in the stirring chamber 3 continues to rise while the rotational torque fluctuates in the order of increase → decrease → rise. It is preferable to stop before reaching. After the rotation is stopped, the take-out part 17 is opened, and the mixed melt of bamboo powder and resin is taken out (S009). And it cools in air and solidifies. This mixed melt is an inevitable process of manufacturing the bamboo powder composite resin, and the chips crushed in (S011) in FIG. 9 to be described later correspond to pellets of ordinary resin raw materials. Thus, what was mixed and melted at high temperature and high pressure is called a bamboo powder resin mixed melt. In addition, what was heated, cooled, processed, deformed after mixing and melting, and those mixed in other resins are also included in the bamboo powder resin mixed melt.

  At the time of melt mixing, the material to be kneaded made of bamboo powder and 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 the bamboo powder composite resin of the present invention, the steam release mechanism 20 maintains a balance of the inflow and outflow of water vapor, that is, the water flowing out from the inside of the stirring chamber 3 and the water flowing from the outside into the stirring chamber. It is preferable to prevent the inflow of air into the stirring chamber 3 by maintaining a balanced equilibrium state with the air to be released by the release mechanism 20. In the production method of the present invention, immediately after the start of mixing, the pressure in the stirring chamber 3 rapidly increases. At that time, in the steam release mechanism 20, the inflow / outflow of the steam is not in a balanced state, and the stirring is performed. The water vapor inside the chamber 3 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. Moreover, in the manufacturing method of this invention, the inside of the stirring chamber 3 may be in the subcritical state of water. The subcritical state of water means a state lower than the supercritical point of water (temperature: 375 ° C., pressure: 22.00 MPa), and subcritical water is very oxidizable.

  In the method for producing a bamboo powder resin mixed melt according to the present invention, at least 1 second to 10 minutes immediately after the rotational torque exhibits the minimum value while maintaining the pressure in the stirring chamber, that is, after the minimum value is exhibited. More preferably, it is preferable to perform melt mixing while preventing inflow of oxygen and protecting bamboo powder and resin from decomposition due to oxygen oxidation or hydration for 1 second to 2 minutes, and more preferably 1 second to 30 seconds. Further, due to the problem of the strength of the apparatus, when the pressure in the stirring chamber is higher than around 23.00 MPa, there is a high probability that troubles such as failure of the rapid pressure rise and damage to the stirring chamber itself will occur. Although it is sufficient to increase the strength of the apparatus, the cost for that is very expensive, which is not economical.

FIG. 9 is a diagram for explaining an example of the procedure of the manufacturing method from the bamboo powder resin mixed melt to the bamboo powder composite resin. First, the mixed melt is pulverized using a pulverizer (S011). Next, the pulverized mixed melt is put into a molding machine and molded (S012). When this bamboo powder composite resin is used, injection molding is possible in addition to extrusion molding and press molding. In this way, a molded body can be obtained (S013). Thus, what was grind | pulverized and shape | molded from the bamboo powder resin mixed melt is called bamboo powder composite resin. In addition, what was heated, cooled, processed, deformed after molding, and those mixed with other resins in other resins are also included in the bamboo powder composite resin.
If high-concentration bamboo powder is produced as a mixed melt in a closed-type mixing and pulverizing apparatus and pulverized into pellets, it is mixed with this and normal pure resin pellets at an appropriate ratio and then applied to a resin molding machine. Bamboo powder composite resin moldings with different composite concentrations (low concentrations) can be produced.
A molded body made of such bamboo powder composite resin has higher bending strength and better moldability than conventional wood powder composite resin, so it can be used not only for tableware and trays, but also for furniture, building materials and toys. Applications to electronic devices, electronic parts, musical instruments, medical devices, etc. are also expected.
In particular, there is an increasing expectation for replacement of thermosetting plastics used in reinforced plastics, which are widely used in aircraft fuselages and are also expanding in passenger cars. It is growing. If realized, it will not only reduce costs, but it can also be recycled because it is a thermoplastic, contributing to global warming countermeasures.

  In the present invention, the bamboo powder composite resin increases the physical strength by 1.5 times to 4 times in terms of bending strength, tensile strength, heat resistance, etc., depending on the amount of bamboo powder combined. Therefore, when an additive is added to increase the strength with a conventional additive, the additive can be reduced by increasing the strength with bamboo flour. In addition, impact resistance may decrease due to bamboo powder composite. In this case, by adding various additives other than bamboo powder and resin, adding rubber-based elastomer or increasing the amount of bamboo powder Can be supplemented.

EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to these at all.
The bamboo powder used in the present invention is a porous bamboo powder obtained by pulverizing a bamboo basket obtained by removing the branches and leaves of natural bamboo powder with a special bamboo powder manufacturing machine 31. Bamboo powder having an average particle size of about 300 μm, which is a powder in which the porosity of the bamboo vascular bundle is retained. The moisture content is about 35%.
Such bamboo powder was put together with resin (PE or PP) powder into the stirring chamber 3 of the closed mixing and grinding apparatus 1, mixed and melted to obtain a bamboo powder resin mixed melt.

  The obtained bamboo powder resin mixed melt was crushed to about 25 mm using a crusher to obtain bamboo powder resin mixed melt pellets. Each of the obtained bamboo powder resin mixed melt pellets was put into an injection molding machine and injection molded to obtain a plate-shaped test piece. And according to JIS specification, the maximum load (bending elastic modulus) etc. just before the fracture | rupture of each test piece were measured, and it described together in Table 1.

Table 1 is a table showing an example of increase in physical property strength of resin by bamboo powder composite.
Bamboo powder composites increase PPM (polypropylene) 100%, bamboo powder 60% -PP40%, bamboo powder 70% -PP30% and increase the bamboo powder content, but the MFR (material flow) decreases, but the density and tensile yield. It can be seen that the strength, flexural modulus, and flexural strength are increasing, and the tensile and flexural strength is improved. In particular, the bending elastic modulus of bamboo powder is 70%, which is 4170 MPa, which is more than four times that of PP100%. Also, as the bamboo powder content increases, the impact strength (durometer hardness) decreases, but it is restored by increasing the additive (elastomer) or increasing the amount of bamboo powder, the surface hardness is softened, the deflection temperature under load Becomes higher.

FIG. 10 shows an example of an electron micrograph of the bamboo powder composite resin. It is a photograph of a composite resin in which 70% bamboo powder and 30% PP are mixed and melted. The total length of the scale at the lower right of the figure is 50 μm. When bamboo powder and PP are mixed and melted in a subcritical state of water, PP enters the porous pores of bamboo powder and solidifies when it returns to room temperature. As a result, the mechanical characteristics and thermal characteristics of the resin alone are improved. Regarding the thermal characteristics, the deflection temperature under load in Table 1 is 91 ° C. when PP is 100%, but is greatly improved to 149 ° C. when bamboo powder is 70%.
That is, increasing the bamboo powder content increases the bending strength, improves the thermal characteristics, and at the same time exhibits antibacterial properties.

As shown in FIG. 10, in the bamboo powder composite resin according to the present embodiment, thermoplastic plastic is melted and infiltrated up to the porous portion of the fine bamboo powder. In conventional FRP (carbon fiber reinforced plastic), it is quite difficult to infiltrate the plastic into the carbon fiber network, and it is therefore considered that it is considerably difficult to form a sheet for use in an aircraft body. However, in the present embodiment, the plastic is already infiltrated into the fine bamboo powder in the melt mixing stage, and injection molding is possible. In addition, FRP uses thermosetting epoxy resin, etc., so it cannot be recycled, but in this example it can be recycled because it uses thermoplastic resin, and the recyclable type recommended by the Ministry of the Environment for measures against greenhouse gases. It can greatly contribute to the expansion of the use of biomass plastics.
Whenever the amount of bamboo powder compound changes, rather than producing a bamboo powder resin mixed melt with a closed-type mixing and grinding device, the mixed melt is produced as a standard at a high concentration that allows a bamboo powder concentration of 70% or more. As a mother pellet, an appropriate amount of resin can be added at the time of molding by a molding machine to obtain a compound having a different composite amount of bamboo powder.

  Using the bamboo powder resin mixed melt of the present invention, a molded body can be produced by various molding methods. As a molding method, a general molding method can be used and is not particularly limited. Examples include injection molding, extrusion molding, compression molding, rotational molding, hollow molding (blow molding), die molding, inflation molding, calendar molding, and the like. There is no limit. Further, the shape of the molded body is not particularly limited, and any shape may be produced by any molding method. It is important to judge the combined amount of bamboo powder by comprehensively judging physical properties and quality.

FIG. 11 shows an example of a photograph of a molded body 40 made of bamboo powder composite resin.
Bamboo powder 70% -PP30% can be easily injection-molded even with a complicated shape such as a test piece in the figure.
From the results of Examples, the thermoplastic resin composition, which is a bamboo powder resin mixed melt obtained by this production method, can be molded without any problem by injection molding, and has excellent moldability.

  The composite material of wood and resin has been conventionally known as wood plastic. However, the affinity between the wood and the resin was not great, and the wood content was at most 30 to 50%. Further, since they are not melted and are mixed, the molding method is limited to simple press molding and extrusion molding, and injection molding cannot be performed.

  However, when bamboo is used, 60 to 70% can be mixed, and injection molding is also possible at 60 to 70%. Bamboo has a high moisture content of 35%, but there is no problem because it becomes hot and volatilizes during mixing and melting. On the contrary, the pressure does not increase without water, which is disadvantageous for mixing and melting. On the contrary, it is better to have some moisture. Also, mixing bamboo will increase the strength of the plastic. High performance plastic. In addition, because the bamboo content can be increased, the possibility of developing new and diverse high-performance plastics has expanded. In addition, development of a composite resin having biodegradability is progressing in the EU, but when polylactic acid and bamboo are combined, the biodegradability can be maintained and the EU standard can be met, which is in a desirable direction. In addition, plastics can be applied not only to polyethylene and polypropylene but also to thermoplastics in general. In addition, when the present invention is used for biomass plastics, it is possible to expand the range of biomass resources standards and product types of the Japan Organic Resource Association and the Bioindustrial Association. Moreover, since injection molding is possible, it can be applied to various moldings, and the use can be greatly expanded. And the cost of product development can be reduced.

  As described above, according to the present invention, the bamboo powder composite resin, bamboo powder resin mixed melt having a high content of cellulosic material, using bamboo powder having a porous interior, a large particle size and a high water content, and These manufacturing methods can be provided. Moreover, the range of the new composite resin which can be manufactured can be expanded, and the molded object which has favorable intensity | strength characteristics and can be remolded can be provided.

  INDUSTRIAL APPLICABILITY The present invention can be used for a cellulose composite resin in which the molded article has good strength characteristics and can be reshaped. It can also be used as a building material or vehicle material.

DESCRIPTION OF SYMBOLS 1 Sealing type mixing and grinding apparatus 2 Machine base 3 Stirring chamber 4 Bearing 5 Rotating shaft 6 Pulley 7 V belt 8 Motor 10 a to 10 f Rotary blade 11 Stirring chamber vertical wall 12 Spiral blade member 13 Material supply chamber 14 Material input section 15 Shutter 17 Extraction section 20 Steam release mechanism 21 Control panel 22 Spiral groove 23 Steam outflow direction 24 Air inflow direction 31 Special bamboo powder manufacturing machine 32 Milling tool 33 Milling cutter 34 Tip 35 End face of milling tool body 36 Cutter driving section 37 Bamboo Material feed mechanism 38 Support means 39 Base 40 Molded body I Minimum value M of rotational torque Maximum value t of rotational torque t A certain time after rotational torque reaches the minimum value tI Time when rotational torque is the minimum value tM Rotational torque Time T when the maximum value T Rotational torque W Bamboo material X Rotation center axis Y Bamboo material movement direction Z Fly Direction of rotation of the cutter

Here, the bamboo powder composite resin refers to a mixture of bamboo powder and resin that is integrated and integrated, but here, what is mixed and melted at high temperature and high pressure is a bamboo powder resin mixed melt, then pulverized and molded This is called bamboo powder composite resin. In addition, those that are heated, cooled, processed, deformed after mixing and melting, and those that are mixed in other resins are also included in the bamboo powder resin mixed melt, and those that are heated, cooled, processed, deformed after molding, other Those mixed in the resin are also included in the bamboo powder composite resin.
After stopping the rotation, it can be taken out as a bamboo powder resin mixed melt. Next, it is pulverized to a size that can be put into a molding machine and molded by a plastic molding machine to produce a bamboo powder composite resin. The bamboo powder resin mixed melt is melted again in the process of being molded by various molding machines to become a plastic product as a molded body. That is, by making the bamboo powder resin mixed melt taken out as a melt from the mixing and grinding device, unlike the conventional biomass kneading method, while combining the high proportion of biomass such as 70% or 60% bamboo powder, Molding with an injection molding machine that injects from the nozzle to the mold becomes possible, and bamboo powder composite resin is produced including other moldings. Further, “immediately after” refers to a short period of time after the minimum value is shown, and is preferably at least 1 second to 10 minutes, more preferably 1 second to 2 minutes, and even more preferably 1 second to 30 seconds.
When configured in this way, a bamboo powder composite resin having a porous vascular bundle of bamboo, a large particle size and a high moisture content, and a high content of cellulosic material is provided. The range of new composite resins that can be manufactured can be expanded.

Claims (6)

In a sealed stirring chamber having a rotating shaft provided with a plurality of rotating blades, resin powder and bamboo powder are used as raw materials, the rotating shaft is rotated and melt mixed to produce a bamboo powder resin mixed melt, In the method for producing bamboo powder composite resin, wherein the bamboo powder resin mixed melt is molded to produce bamboo powder composite resin;
The bamboo powder is bamboo powder having an average particle size of 1 μm or more and 800 μm or less and a moisture content of 5 to 40% by mass, and the temperature in the stirring chamber during the melt mixing is 150 ° C. or more and 370 ° C. or less, pressure 0.20 MPa or more and saturated steam or less, and the rotational torque of the rotating shaft decreases to reach a minimum value, and immediately after the rotation starts to stop, the rotation is stopped to produce a bamboo powder resin mixed melt, Furthermore, the bamboo powder resin mixed melt is pulverized and molded to produce a bamboo powder composite resin;
A method for producing bamboo powder composite resin. The bamboo powder is provided with a plurality of rows of chips arranged in a radial direction on the end face of the tool body to which the chips that are cutting edges are attached, and each chip of a pair of adjacent chip rows is It is a fine powder pulverized using milling tools arranged in a staggered pattern with different radial distances from the rotation center axis, and the porous structure of the bamboo vascular bundle is observed by electron micrographs. 10 ³ to 10 ¹¹ / g of lactic acid bacteria grow inside, and the weight ratio of the bamboo powder to the resin is 5:95 to 95: 5;
The method for producing a bamboo powder composite resin according to claim 1. In a sealed stirring chamber having a rotating shaft provided with a plurality of rotating blades, resin powder and bamboo powder are used as raw materials, the rotating shaft is rotated and melt mixed to produce a bamboo powder resin mixed melt, In the method for producing bamboo powder composite resin, wherein the bamboo powder resin mixed melt is molded to produce bamboo powder composite resin;
The bamboo powder is bamboo powder having an average particle size of 1 μm or more and 800 μm or less and a moisture content of 5 to 40% by mass, and the temperature in the stirring chamber during the melt mixing is 150 ° C. or more and 370 ° C. or less, pressure Is 0.20 MPa or more and saturated water vapor or less, and the rotation torque of the rotating shaft decreases to reach a minimum value, and immediately after the rotation starts to increase, the rotation is stopped to produce a bamboo powder resin mixed melt. Characterized by:
A method for producing a bamboo powder resin mixed melt. The bamboo powder is provided with a plurality of rows of chips arranged in a radial direction on the end face of the tool body to which the chips that are cutting edges are attached, and each chip of a pair of adjacent chip rows is It is a fine powder pulverized using milling tools arranged in a staggered pattern with different radial distances from the rotation center axis, and the porous structure of the bamboo vascular bundle is observed by electron micrographs. 10 ³ to 10 ¹¹ / g of lactic acid bacteria grow inside, and the weight ratio of the bamboo powder to the resin is 5:95 to 95: 5;
A method for producing a bamboo powder resin mixed melt according to claim 3. It was manufactured by the method for manufacturing a bamboo powder resin mixed melt according to claim 3 or claim 4;
Bamboo powder resin mixed melt. It was manufactured with the manufacturing method of the bamboo-powder composite resin of Claim 1 or Claim 2;
Bamboo powder composite resin.

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