JP6739047B2 - Bamboo powder composite resin manufacturing method, bamboo powder resin mixed melt manufacturing method, bamboo powder resin mixed melt, and bamboo powder composite resin - Google Patents

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. More specifically, 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, in which porous fine bamboo powder is combined with a resin by high temperature/high pressure melting.

Examples of the cellulose-based composite resin in which resin is combined with wood-based biomass include a wood deck commonly called wood plastic. This aims to use an inexpensive manufacturing method and uses recycled wood and recycled plastic as raw materials. In order to combine wood powder with plastic, it has been considered that wood powder is fine and does not contain water, for example, an average particle size of 10 μm or less and a water content of 5% or less from the plastic side. That is, when the particle size is large and the water content is high, the wood powder does not mix well into the plastic. As a result, wood flour contained only 30 to 50% at most. Further, in order to obtain a molded body in which 30 to 50% of wood powder is compounded, it has been limited to a product having a simple shape molded by extrusion molding or press molding. The wood-powder composite resin has the advantage of combining the goodness of a resin that looks like wood and the goodness of a resin, but on the other hand, it has a weakness that is neither of them. Thus, there are problems in quality maintenance and productivity.
Recently, a technique focusing on high strength, high elasticity, and low thermal expansion property using cellulose nanofiber (CNF) has been widely taken up, but it is far from practical use.

Focusing on bamboo fibers, there have been several attempts to pulverize bamboo with steam, decompose it into filaments, and cut it into fine particles to combine it with resin, but none has yet been put to practical use. A conventional kneading apparatus using a resin manufacturing technique can melt bamboo at a temperature of about 100° C. and mix the bamboo powder, but the bamboo can be kneaded at a low purity and is not a melt-integrated composite resin. There are also attempts to add antibacterial fillers in order to exert antibacterial properties from the original ingredients of bamboo.

On the other hand, there are many bamboo materials in Japan, and if they can be mixed with plastics, they are expected to become fiber reinforcing agents, but it is difficult to make fine powder with an average particle size of 400 μm or less, and it is not possible to increase the water content to 35% or less. Due to the difficulty, it was a big wall to combine with plastic.

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

In addition, when a cellulosic material and a plastic binder are mixed and pulverized using a mixing and pulverizing device manufactured by M&F Technology Co., Ltd., the above materials are mixed and pulverized in a mixing container, and due to heat generated by shearing, friction and compression, water content is generated. The ingredients are dehydrated. Next, due to the collision energy at the time of mixing and pulverizing, the particles finally become fine powder particles, and a rapid temperature rise occurs. Then, unlike the simple mixing in the conventional technique, the inside of the mixing container is in a high temperature and high pressure state in an instant. Next, the free water existing in the voids such as cell lumens and intercellular spaces and the voids in which bound water contained in the cell wall escaped, the ratio of lignin, which is the second largest after cellulose in wood, mediated, and the heat of the binder A plastic resin (polypropylene PP, polyethylene PE, biodegradable resin, etc.) enters and melts and integrates uniformly and with a strong binding force with cellulose and the like that make up wood, which cannot be seen by simple mixing. In other words, since lignin is a natural polymer with a three-dimensional network structure composed of three monoglinol polymers, it can be considered that the molten cellulose component is impregnated into the dehydrated cellulose component due to the affinity with the binder polymer. (See Patent Document 3). That is, by using the above mixing and pulverizing device, it is possible to mix and melt the cellulosic material and the plastic.
Then, a cellulose composite resin is produced for pulp and kenaf using such a mixing and pulverizing device (see 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 of producing fine bamboo powder by a special bamboo powder producing machine having a special milling tool and a technique of mixing and melting a cellulosic material and a plastic using a mixing and pulverizing device, By using bamboo powder as the material, it has been conceived that the reinforced plastic can be formed by overcoming the wall.
The present invention provides a bamboo powder composite resin having a high content rate of a cellulosic material, a bamboo powder resin mixed melt, and a manufacturing method thereof, using bamboo powder having a large particle size and a high water content, It is an object of the present invention to expand the range of various composite resins and to provide a remoldable molded product having good strength characteristics.

The method for producing a bamboo powder composite resin according to the first aspect of the present invention is a method for producing a bamboo powder resin mixed melt by melting and mixing resin powder and bamboo powder as raw materials in the stirring chamber 3 of the closed-type mixing and pulverizing device 1. It is a manufacturing method of a bamboo powder composite resin, which is manufactured and a bamboo powder resin mixed melt is molded to manufacture a bamboo powder composite resin. In this manufacturing method, for example, as shown in FIG. 8, bamboo powder is a bamboo powder having an average particle size of 1 μm or more and 800 μm or less (S001) and a water 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 water vapor or less, and the rotation torque of the rotating shaft 5 decreases to reach the minimum value, and further increases. Immediately after (S007), the rotation is stopped (S008) to produce a bamboo powder resin mixed melt (S009). Then, for example, as shown in FIG. 9, the bamboo powder resin mixed melt is crushed (S011) and molded (S012) to produce a bamboo powder composite resin (S0013). Further, as shown in FIG. 4, the closed type mixing and pulverizing device 1 in which the melt mixing is performed has a rotating shaft 5 on which a plurality of rotating blades 10a to 10f are arranged, and the bamboo powder composite resin has its stirring chamber. In 3, the resin powder and the bamboo powder are used as raw materials, and the rotary shaft 5 is rotated to melt and mix them.

Here, the bamboo powder composite resin refers to a material in which bamboo powder and resin are mixed and integrated, but here, a material mixed and melted at high temperature and high pressure is a bamboo powder resin mixed melt, which is then crushed and molded. What is called "bamboo powder composite resin" is used to distinguish them. It should be noted that bamboo powder resin mixed melts include those that have been heated, cooled, processed and deformed after mixing and melting, and those that have been mixed with other resins, and those that have been heated, cooled, processed and deformed after molding, and other Those mixed with resin are also included in the bamboo powder composite resin.
After the rotation is stopped, it can be taken out as a bamboo powder resin mixed melt. Next, it is crushed to a size that can be put into a molding machine and molded with 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 be a plastic product as a molded body. That is, by using the bamboo powder resin mixed melt taken out as a melt from the mixing and pulverizing device, unlike the conventional biomass kneading method, while combining a high ratio of bamboo powder of 70% or 60%, a small diameter Molding with an injection molding machine that injects from a nozzle into a mold is possible, and bamboo powder composite resin is produced including other moldings. The term “immediately after” refers to a short time after the minimum value is shown, and it is preferably at least 1 second to 10 minutes, more preferably 1 second to 2 minutes, still more preferably 1 second to 30 seconds.
With this configuration, a bamboo powder having a porous vascular bundle of bamboo, a large particle size and a high water content is used, and a method for producing a bamboo powder composite resin having a high content of a cellulosic material is provided. Therefore, 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, for example, as shown in FIG. 1, FIG. 2A and FIG. The end surface 35 of the tool body to which the chips 34, which are blades, are attached, is provided with a plurality of chip rows in the circumferential direction in which a plurality of tips 34 are arranged in a radial pattern and extend. It is a fine powder pulverized by using a milling tool 32 arranged in a zigzag pattern in which the radial distance from is alternated, and the porous structure of the bamboo vascular bundle is observed by an electron micrograph and It is characterized in that 10 ³ to 10 ¹¹ /g of lactic acid bacteria grow, and the weight ratio of bamboo powder and resin is 5:95 to 95:5.
According to this structure, it is possible to provide bamboo powder as a raw material suitable for producing a bamboo powder composite resin.

The method for producing a bamboo powder resin-mixed melt according to the third aspect of the present invention extracts the step of producing a bamboo powder resin-mixed melt as an intermediate from the method for producing a bamboo powder resin composite according to the first aspect. It is a thing.
According to this structure, it is possible to provide the bamboo powder resin mixed melt as a material suitable for molding the bamboo powder composite resin.

The method for producing a bamboo powder resin mixed melt according to the fourth aspect of the present invention is the step of producing a bamboo powder resin mixed melt as an intermediate from the method for producing a bamboo powder composite resin according to the second aspect. It is a thing.

The bamboo powder resin mixed melt according to the fifth aspect of the present invention is characterized by being manufactured by the method for manufacturing a bamboo powder resin mixed melt according to 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 manufacturing a bamboo powder composite resin according to the first or second embodiment.
With such a configuration, it is possible to provide a bamboo powder composite resin having a high content rate of a cellulosic material, by using bamboo powder having a large particle size and a high water content rate, and having a good strength property and a remoldable shape. The body can be provided.

According to the present invention, it is possible to provide a bamboo powder composite resin having a high content rate of a cellulosic material, a bamboo powder resin mixed melt, and a manufacturing method thereof using bamboo powder having a large particle size and a high water content. The range of new composite resins that can be produced can be expanded, and a remoldable molded article having good strength characteristics can be provided.

It is a schematic diagram of an 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 equipped. It is a model front view of the example of the milling tool with which a special bamboo powder manufacturing machine is equipped. 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 an example of a closed type mixing and pulverizing device. It is a schematic diagram of an example of a rotating shaft in which a plurality of rotary wings are arranged. It is a schematic diagram of an example of a release mechanism of water vapor. It is a figure which shows the example of the time change of rotation 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 a bamboo powder resin mixed melt to a bamboo powder composite resin. It is an example of the electron micrograph of a bamboo powder composite resin. It is a figure which shows the molded object which consists of a bamboo powder composite resin.

In this embodiment, resin powder and bamboo powder are used as raw materials in a stirring chamber of a closed type mixing and pulverizing device having a rotary shaft in which a plurality of rotary blades are arranged, and the rotary shaft is rotated to melt and mix the bamboo powder. An example of a method for producing a bamboo powder composite resin for producing the composite resin will be described. Further, an example in which fine bamboo powder manufactured by a special bamboo powder manufacturing machine equipped with a special milling tool is used as a raw material will be described.

FIG. 1 shows a schematic view of an example of a special bamboo powder manufacturing machine used in the present invention.
The special bamboo powder manufacturing machine 31 used in the method for manufacturing a bamboo powder composite resin of the present invention belongs to a dry bamboo powder manufacturing machine. Bamboo (bamboo material) W with an outer diameter of 8 cm or more of Moso bamboo or bamboo is dropped, washed well and grasped the outer diameters of both ends to be positioned, and the end face 35 (33 ~ of the mortar-shaped milling tool 32 on the right end 35 is a drawing (see FIG. 2) is provided with a cutter 33 in which the carbide insert tips 34 are arranged in a radial pattern, and is rotated by the cutter drive unit 36, and the bamboo material W is not rotated from the left end toward the cutter 33. Fine bamboo powder is produced by cutting while feeding by the feeding mechanism 37 (see Patent Documents 1 and 2). The bamboo material W is supported by the supporting means 38, mounted on a slidable base 39, and moves toward the cutter 33. The bamboo powder in the present invention is not limited to this. Further, it is not particularly limited as long as it is bamboo powder crushed from raw bamboo. In addition, X is an axis line of the rotation center.

2A and 2B show schematic views of examples of milling tools provided in the special bamboo powder manufacturing machine. 2A is a cross-sectional view including the rotation center axis, and FIG. 2B is a front view.
The milling tool 32 is provided with a plurality of rows of milling cutters 33 each having a row of tips extending in the circumferential direction, in which a plurality of tips 34 are radially arranged on an end surface 35 of a tool body to which a tip 34 that is a cutting edge is attached. The chips 34 of a pair of adjacent chip rows 33 are arranged in a zigzag pattern in which radial distances from the rotation center axis are alternately different. The bamboo powder used in the present invention is a fine powder pulverized using a milling tool 32, has a water content of 5 to 40% by mass, and a porous structure of a bamboo vascular bundle is observed by an electron micrograph, Lactobacillus of 10 ³ to 10 ¹¹ /g grows and the weight ratio of bamboo powder and resin is 5:95 to 95:5. Note that 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.
The bamboo material W has a hollow cylindrical shape, and the inside of the bamboo culm is an innumerable bamboo vascular bundle (pathway for water and nutrients) that is cut at right angles to the axis to produce bamboo powder. Has a honeycomb-like porous structure of 20 μm inside.
Bamboo powder has a particle size of 1 to 800 μm, and lactic acid bacteria of a number of about 10 ³ to 10 ⁴ live in the inside immediately after crushing. This is sealed in a bag and left to stand for about 2 weeks to accelerate fermentation and grow the number of lactic acid bacteria to 10 ⁸ to 10 ¹¹ .

The bamboo powder used in the present invention is preferably a fine bamboo powder that retains porosity obtained by crushing bamboo culms excluding the branches and leaves of natural bamboo powder with a special bamboo powder maker. Since this bamboo powder has a high degree of homogeneity in its color and shape, it has a uniform hue when formed into a molded product, and even when the molded product is colored by mixing a masterbatch 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 can be used as long as it has no thread-like fibers that can be visually recognized and the porosity of the bamboo fiber bundle is retained. The size of bamboo powder is not particularly limited, but is preferably 400 μm or less, more preferably 200 μm or less. Non-porous bamboo powder produced by another bamboo crushing machine (usually referred to as a chipper or shredder) may deteriorate the physical strength during resin molding and the surface finish quality.

The bamboo powder used in the present invention preferably has a water content of 5 to 30 mass %. When the water content of the cellulose is within 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 inside the stirring chamber does not rise even over time, so water may be replenished and added.
If the water content is more than 35% by mass, it takes a long time to dehydrate the bamboo powder, so that the melting time becomes long and the bamboo powder may be easily decomposed. The water content is more preferably 8 to 35% by mass, further preferably 10 to 25% by mass.

FIG. 4 is a schematic view of an example of the closed type mixing and pulverizing 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, there are a plurality of laterally cylindrical stirring chambers 3 on a machine base 2 and a plurality of material supply chambers 13 in which a material feeding section 14 and a spiral blade member 12 are arranged. Placed by the legs of the. The rotating shaft 5 is horizontally supported by the bearings 4 and 4 arranged on the legs at both ends, and the rotating shaft 5 is coaxially inserted through 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 rotationally connected to a motor 8 as a drive source via a belt 7.

FIG. 5 is a schematic diagram of an example of a rotary shaft on which a plurality of rotary vanes are arranged. On the outer periphery of the rotary shaft 5 that is disposed so as to penetrate through the stirring chamber 3, for example, the rotary blades 10a to 10f having a total of six rectangular cross-sections and a rectangular overall shape are provided on the circumference of the rotary shaft 5. The projections are provided so as to face each other in the axial direction at portions at angular intervals of 180 degrees in the direction. The rotary blades 10a and 10f at both ends in the axial direction of the rotary blades 10a and 10f, when rotated clockwise as viewed from the right side of FIG. 4, have their front edges formed with the inner surfaces of the vertical walls 11, 11 at both ends of the stirring chamber 3. It is fixed to the outer circumference of the rotary shaft 5 so that it is in sliding contact with almost no gap. Further, the four rotary blades 10b, 10c, 10d, 10e in the middle portion are fixed to the outer peripheral surface of the rotary shaft 5 in a zigzag manner, and the front edges of the rotary blades are arranged so as to face both ends of the stirring chamber 3. ing.

The motor 8 side of the vertical walls 11 at both ends of the stirring chamber 3 is a material supply port of the stirring chamber 3 opened in one end wall of the stirring chamber 3, and 12 is a spiral formed on the outer circumference of the rotating shaft 5. Is a material supply blade member, 13 is a material supply chamber that surrounds the supply screw, 14 is a material feeding portion provided above the material feeding chamber 13, and after feeding the material into the material feeding portion 14. A shutter 15 that can be opened and closed so as to maintain hermeticity during melt mixing is provided.

FIG. 6 is an enlarged schematic view of 20 examples of the water vapor release mechanism. The closed type mixing and pulverizing apparatus 1 used in the present invention is provided with water vapor release mechanisms 20 at both ends of the rotary shaft 5. A spiral groove 22 is cut in a part of the rotary shaft that constitutes the water vapor release mechanism 20, and when the rotary shaft 5 rotates, a right-hand screw so that air is sent into the stirring chamber 3 from the outside, 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 into the stirring chamber from the outside. Further, in the present invention, since the inside of the stirring chamber 3 is in an extremely high pressure state during melt mixing, the high-pressure steam inside the stirring chamber tends to leak outward toward the steam outflow direction 23 (arrow). However, in the water vapor release mechanism 20, since the distance between the outermost peripheral portion of the spiral groove 22 cut on the rotary shaft 5 and the outer wall portion is small, both of them collide with each other at this portion and eventually the balance is reached. Will be kept.

The rotary shaft 5 on which the rotary blades are arranged is connected to a motor 8 which is a drive source. In the closed type mixing and pulverizing apparatus 1 used in the present invention, a torque meter (not shown) for measuring the rotary torque applied to the motor 8 is used. ) Is installed, the rotational torque can be monitored on the control panel 21 (see FIG. 4). In the method of manufacturing a bamboo powder composite resin of the present invention, the change in the rotation torque of the rotary shaft 5 provided with the rotary blades 10a to 10f measured by the torque meter is measured to determine the end point of the melt mixing. ..

FIG. 7 is a diagram showing an example of the change over time of the rotational torque T. The rotation torque T applied to the main shaft of the motor 8 increases according to the mixing and crushing and drying conditions of the material in the closed-type mixing and crushing device 1, reaches a maximum value M (time t _M ), and then decreases to a minimum value I. After a lapse of a certain time t after reaching (time t _I ), the mixed powder is pulverized and dehydrated by the take-out section 17 (see FIG. 4) of the closed-type mixing and pulverizing apparatus 1 to impregnate the resin with the bamboo powder and the resin. Take out the mixed melt. The measure of the ending operation according to the measured value of the rotating torque is indispensable for the material to be handled for the first time, but when the same material is used constantly, it is not always necessary to measure each time, and the required time for melting and mixing is based on actual results. It may be determined in advance, and the end point may be determined according to the determined melt mixing time.

In the method for producing a bamboo powder composite resin according to the present invention, the temperature and pressure conditions under which the bamboo powder and the resin are melt-mixed in the stirring chamber 3 of the closed-type mixing and pulverizing apparatus 1 are in the temperature range of 150 to 370° C. -370 degreeC is more preferable, 250-370 degreeC is still more preferable, Moreover, a pressure range is 0.20MPa-saturated steam pressure in a melt-mixing temperature, and its saturated steam-pressure in a melt-mixing temperature is more preferable. In the present invention, it is even more preferable to carry out the melt mixing in a subcritical state of water in which the temperature or pressure is slightly lower than the temperature of 375° C., which is a supercritical state of water, and the pressure of 22.00 MPa.

The saturated steam pressure in the present invention means that the steam pressure in the stirring chamber does not exceed the saturated steam pressure as long as the melting and mixing temperature is constant during melt mixing and the internal volume of the stirring chamber does not change.

FIG. 8: is a figure explaining the example of the procedure of the manufacturing method of the bamboo powder resin mixed melt of this invention. The prepared bamboo powder is cut and crushed by the special bamboo powder maker 31 to obtain crushed lactic acid fermentation fine powder (S001). Next, the bamboo powder and the resin are put into a closed type mixing and pulverizing device (S002). The bamboo powder and the resin may be premixed with a blender or the like before being charged, or may be sequentially charged into the stirring chamber 3. When the bamboo powder and the resin are directly charged into the stirring chamber 3 without premixing, it is preferable that the rotating blades 10a to 10f inside the stirring chamber 3 are rotated at a low speed. After the bamboo powder and the resin are put into the stirring chamber 3, the stirring chamber 3 is hermetically closed and the rotary blades 10a to 10f are rotated at high speed (S003). The bamboo powder and the resin receive a strong shearing force, and the temperature inside the stirring chamber 3 rapidly rises. As the temperature rises sharply, the water content of the bamboo powder evaporates and becomes steam, and the inside of the stirring chamber 3 is filled with steam and the internal pressure rises rapidly (S004). Further, when the temperature inside the stirring chamber 3 exceeds the softening temperature and the 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 progress of melt mixing is grasped by measuring the rotation torque of the rotary shaft 5 on which the rotary blades 10a to 10f are arranged (S006), and You can identify the stoppage. That is, the rotational torque increases as the number of rotations of the rotary blades 10a to 10f increases, but the thermal melting of the resin starts with the increase in the temperature of the material to be kneaded. It keeps decreasing as the heat melting of the resin progresses. At this time, the melt mixing of the bamboo powder and the resin has started, and the interaction torque at the interface between the bamboo powder and the resin increases, so that the rotational torque once exhibits a minimum value, then reverses and begins to rise again. (S007). In the present invention, the rotation of the rotary shaft 5 is stopped immediately after the rotation torque starts to rise again (S008). In the present invention, the temperature in the agitation chamber 3 continues to rise even while the rotational torque fluctuates from rising → lowering → rising, but in the melt mixing, the thermal decomposition temperature of the material to be kneaded after re-raising the rotating torque. It is preferable to stop before reaching. After the rotation is stopped, the take-out portion 17 is opened and the mixed melt of bamboo powder and resin is taken out (S009). Then, it is cooled in the air and solidified. This mixed melt is an inevitable process of manufacturing the bamboo powder composite resin, and the chips crushed in (S011) in FIG. 9 described later correspond to pellets of a normal resin raw material. Such a mixture melted at high temperature and high pressure is called a bamboo powder resin mixed melt. Bamboo powder resin mixed melts include those that have been heated, cooled, processed and deformed after mixing and melting, and those that have been mixed with other resins.

During melt mixing, the material to be kneaded, which is composed of bamboo powder and resin, must be protected from oxidative decomposition. In particular, suppression of oxidation by oxygen is important for suppressing changes in the physical properties of the material to be kneaded. Therefore, in the method for producing a bamboo powder composite resin of the present invention, in the steam releasing mechanism 20, a state in which the steam inflow and outflow are balanced, that is, the steam flowing out of the stirring chamber 3 and flowing into the stirring chamber from the outside. It is preferable to prevent the inflow of air into the stirring chamber 3 by maintaining a balanced state of balance 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 rises, and at that time, the steam inflow and outflow is not in a balanced state in the steam releasing mechanism 20, and the stirring is not performed. The water vapor inside the chamber 3 flows out from the release mechanism. During this time, the pressure inside the stirring chamber tends to decrease and finally reaches an equilibrium state to maintain a constant pressure. Further, in the manufacturing method of the present invention, the inside of the stirring chamber 3 may be in a subcritical state of water. The subcritical state of water is a state lower than the supercritical point of water (temperature 375° C., pressure 22.00 MPa), and the subcritical water has a very strong oxidizing property.

In the manufacturing method of the bamboo powder resin mixed melt of the present invention, at least 1 second to 10 minutes immediately after the rotational torque shows the minimum value in the state where the pressure in the stirring chamber is maintained, that is, after the minimum value is shown. It is preferable to perform the melt mixing for 1 second to 2 minutes, more preferably for 1 second to 30 seconds while preventing the inflow of oxygen and protecting the bamboo powder and the resin from decomposition by oxygen oxidation or hydration. Further, due to the problem of the strength of the apparatus, if the pressure in the stirring chamber is higher than around 23.00 MPa, there is a high probability that troubles such as the stirring chamber itself being damaged without being able to withstand a rapid pressure increase will occur. Although it is necessary to increase the strength of the device, it is economically not preferable because the cost is very high.

FIG. 9: is a figure explaining the example of the procedure of the manufacturing method from a bamboo powder resin mixed melt to a bamboo powder composite resin. First, the mixed melt is crushed using a crusher (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 is crushed and molded from the bamboo powder resin mixed melt is called bamboo powder composite resin. Bamboo powder composite resins include those that are heated, cooled, processed and deformed after molding, and those that are mixed with other resins in other resins.
If high-concentration bamboo powder is produced as a mixed melt in a closed-type mixing and pulverizing device and crushed and pelletized, it is mixed with normal pure resin pellets at an appropriate ratio, and then applied to a resin molding machine to produce bamboo powder. Bamboo powder composite resin moldings having different composite concentrations (low concentrations) can be produced.
Molded products made from such a bamboo powder composite resin have higher bending strength and better moldability than conventional wood powder composite resins, so they can be used not only for tableware and trays but also for furniture, building materials, toys, and vehicles. It is also expected to be applied to electronic equipment, electronic parts, musical instruments, medical equipment, etc.
In particular, there is growing hope for a substitute for the thermosetting plastics used in reinforced plastics that are widely used in aircraft fuselage and are expanding in use in passenger cars, and it is possible that prototypes will begin in collaboration with the Reinforced Plastics Association. It is rising. If realized, not only will costs be reduced, but it will also be possible to recycle because it is a thermoplastic, which will contribute to global warming countermeasures.

In the present invention, the bamboo powder composite resin has a physical strength increased by 1.5 to 4 times in bending strength, tensile strength, heat resistance, etc. depending on the amount of the bamboo powder composited. Therefore, when an additive is conventionally added to increase the strength by the additive, the amount of the additive can be reduced by increasing the strength with the bamboo powder. In addition, the impact resistance may decrease due to the combination of bamboo powder, and in this case, by adding various additives other than bamboo powder and resin appropriately, it is possible to add a rubber elastomer or increase the amount of bamboo powder. Can be supplemented.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
The bamboo powder used in the present invention is a fine bamboo powder that retains its porosity obtained by crushing bamboo culms excluding the branches and leaves of natural bamboo powder with a special bamboo powder manufacturing machine 31. It is a powder that retains the porosity of the bamboo vascular bundle and has an average particle size of about 300 μm. The water content is about 35%.
The bamboo powder and the resin (PE or PP) powder were put into the stirring chamber 3 of the closed type mixing and pulverizing apparatus 1 and 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 placed in an injection molding machine and injection-molded to obtain a plate-shaped test piece. Then, according to the JIS standard, the maximum load (flexural modulus) immediately before fracture of each test piece was measured, and the results are shown in Table 1.

Table 1 is a table showing an example of the increase in the physical strength of the resin due to the composite of bamboo powder.
With the combination of bamboo powder, PP (polypropylene) 100%, bamboo powder 60%-PP40%, bamboo powder 70%-PP30%, and MFR (material flow) decrease with increasing bamboo powder content, but density and tensile yield It can be seen that the strength, flexural modulus, and flexural strength have increased, while the tensile and flexural strength has improved. In particular, the bending elastic modulus of bamboo powder 70% is 4170 MPa, which is four times or more that of PP 100%. Moreover, impact strength (durometer hardness) decreases with an increase in the content of bamboo powder, but it is restored by an increase in the amount of additives (elastomer) or the amount of bamboo powder, the surface hardness softens, the deflection temperature under load. Will be higher.

FIG. 10 shows an example of an electron micrograph of the bamboo powder composite resin. It is a photograph of a composite resin obtained by mixing and melting bamboo powder 70% and PP 30%. 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 the temperature returns to room temperature. As a result, the mechanical properties and thermal properties of the resin alone are improved. Regarding the thermal characteristics, it is shown that the deflection temperature under load in Table 1 is 91°C when PP is 100%, but is significantly improved to 149°C when bamboo powder is 70%.
That is, the increase in the content of bamboo powder increases the bending strength, improves the thermal characteristics, and simultaneously exhibits the antibacterial property.

As shown in FIG. 10, in the bamboo powder composite resin according to this example, the thermoplastic plastic was melt-infiltrated to the porous portion of the fine bamboo powder. With conventional FRP (carbon fiber reinforced plastic), it is quite difficult to infiltrate the plastic into the carbon fiber network, and therefore it is presumed that it is considerably difficult to form a sheet for use in the body of an aircraft. However, in this embodiment, since the fine bamboo powder has been infiltrated with the plastic at the melt mixing stage and injection molding is possible, it is presumed that it is easy to form a sheet. Further, FRP cannot be recycled because it uses a thermosetting epoxy resin, but in this example, it is recyclable because it uses a thermoplastic resin, and is a recyclable type recommended by the Ministry of the Environment as a measure against global warming gas. It can greatly contribute to expanding the use of biomass plastics.
Each time the combined amount of bamboo powder changes, a mixed melt is manufactured as a standard to a high concentration that allows a bamboo powder concentration of 70% or more, rather than a bamboo powder resin mixed melt produced by a closed-type mixing and pulverizing device. As the mother pellets, a proper amount of resin can be added at the time of molding by a molding machine to obtain molded bodies having different combined amounts of bamboo powder.

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

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

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

However, when bamboo material is used, 60 to 70% can be mixed, and even 60 to 70% can be injection-molded. Further, the bamboo material has a large water content of 35%, but there is no problem because it volatilizes at a high temperature when mixed and melted. On the contrary, the pressure does not rise without water, which is disadvantageous for mixing and melting. On the contrary, it is better to contain water to some extent. Moreover, the strength of plastic increases when bamboo is mixed. High-performance plastic. Furthermore, since the content of bamboo can be increased, the possibility of developing new and diverse high-performance plastics has expanded. Further, in EU, a composite resin having biodegradability is under development, but when polylactic acid and bamboo are combined, the biodegradability can be maintained and the standard of EU can be satisfied, which is in a desirable direction. As for plastics, not only polyethylene and polypropylene but also thermoplastics in general can be applied. When the present invention is applied to biomass plastics, the scope of biomass resource standards and product types of the Japan Organic Resources Association and the Bioindustrial Association can be expanded. Also, since injection molding is possible, it can be applied to various moldings, and the applications can be dramatically expanded. And the cost increase of product development can be reduced.

As described above, according to the present invention, a bamboo powder composite resin having a high content rate of a cellulosic material, a bamboo powder resin mixed melt, and a porous material having a large particle size and a high water content rate are used according to the present invention. It is possible to provide these manufacturing methods. In addition, the range of new composite resins that can be manufactured can be expanded, and a molded product that has good strength characteristics and can be remolded can be provided.

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

1 Closed Type Mixing and Grinding Device 2 Machine Base 3 Stirring Chamber 4 Bearing 5 Rotating Shaft 6 Pulley 7 V Belt 8 Motors 10a to 10f Rotating Blade 11 Vertical Wall 12 of Stirring Chamber 12 Helical Blade Member 13 Material Supply Chamber 14 Material Feeding Port 15 Shutter 17 Extraction part 20 Water vapor release mechanism 21 Control panel 22 Helical groove 23 Water vapor outflow direction 24 Air inflow direction 31 Special bamboo powder making machine 32 Milling tool 33 Milling cutter 34 Tip 35 End face of milling tool body 36 Cutter driving part 37 Bamboo Material feeding mechanism 38 Support means 39 Base 40 Formed body I Minimum value of rotational torque M Maximum value of rotational torque t Constant time after rotational torque reaches minimum value tI Time when rotational torque is minimum value tM Rotational torque Is the maximum time T Rotation torque W Bamboo material X Axis of rotation Y Y Bamboo material movement direction Z Milling cutter rotation direction

Claims (6)

In a closed type stirring chamber having a rotary shaft with a plurality of rotary blades, resin powder and bamboo powder are used as raw materials, and the rotary shaft is rotated to melt and mix to produce a bamboo powder resin mixed melt. In the method for producing a bamboo powder composite resin, the bamboo powder resin mixed melt is molded to produce a bamboo powder composite resin;
The bamboo powder is a bamboo powder having an average particle size of 1 μm or more and 800 μm or less and a water content of 5 to 40% by mass, and the temperature in the stirring chamber at the time of the melt mixing is 150° C. or more and 370° C. or less, and pressure. Is 0.20 MPa or more and saturated water vapor or less, and the rotation torque of the rotary shaft decreases to reach a minimum value, and immediately after the rotation torque starts to increase, the rotation is stopped to produce a bamboo powder resin mixed melt, Further, the bamboo powder resin mixed melt is pulverized and molded to produce a bamboo powder composite resin ;
The weight ratio of the bamboo powder and the resin powder is 5:95 to 70:30;
Bamboo powder composite resin manufacturing method. The bamboo powder is provided with a plurality of rows of chips in the circumferential direction, which are formed by arranging a plurality of chips in a radial pattern on the end surface of the tool body to which the chips, which are cutting edges, are attached. , A fine powder crushed by using a stylus-shaped friece tool arranged in different radial distances from the rotation center axis, and the porous structure of the bamboo vascular bundle was observed by an electron micrograph. is characterized in that the lactic acid bacteria of the interior ¹⁰ 3 ^{~10 11} / g are growing;
The method for producing the bamboo powder composite resin according to claim 1. In sealed stirring chamber having an axis of rotation in which a plurality of rotating blades are provided, the resin powder and bamboo powder as raw materials, the production of bamboo powder resin mixture melt was melt-mixed by rotating the rotary shaft In the manufacturing method of the bamboo powder resin mixed melt ;
The bamboo powder is a 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 at the time of the melt mixing is 150° C. or more and 370° C. or less and pressure. Is 0.20 MPa or more and saturated water vapor or less, and the rotation torque of the rotary shaft decreases to reach a minimum value, and immediately after the rotation torque increases, the rotation is stopped to produce a bamboo powder resin mixed melt. Characterized by;
The weight ratio of the bamboo powder and the resin powder is 5:95 to 70:30;
Bamboo powder resin mixed melt manufacturing method. The bamboo powder is provided with a plurality of rows of chips in the circumferential direction, which are formed by arranging a plurality of chips in a radial pattern on the end surface of the tool body to which the chips, which are cutting edges, are attached. , A fine powder crushed by using a stylus-shaped friece tool arranged in different radial distances from the rotation center axis, and the porous structure of the bamboo vascular bundle was observed by an electron micrograph. is characterized in that the lactic acid bacteria of the interior ¹⁰ 3 ^{~10 11} / g are growing;
A method for producing the bamboo powder resin mixed melt according to claim 3. A bamboo-powder-resin mixed melt in which bamboo powder and resin powder are mixed and melted at high temperature and high pressure, and mixed and integrated;
The temperature range at the time of mixing and melting at the high temperature and high pressure is 150 to 370° C., the pressure range is 0.20 MPa to the saturated steam pressure at the melting and mixing temperature,
The thermoplastic resin is melt-infiltrated to the porous portion of the fine bamboo powder, and the weight ratio of the bamboo powder and the resin powder is 5:95 to 70:30;
Bamboo powder resin mixed melt. The bamboo powder resin-mixed melt according to claim 5 is crushed and injection-molded to produce the product.
Bamboo powder composite resin manufacturing method.

Images