JP2010036529A - Flowability improver for biomass powder, molding using flowability improver, and manufacturing method for molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biomass flowability improver can obtain a biomass molding raw material flowable at low temperature, and a molding using the same. <P>SOLUTION: This flowability improver for enhancing flowability of biomass powder contains a hot-water extract obtained by extraction-treating a bamboo material with hot water, and the molding is molded by heating and pressurizing the molding raw material with the flowability improver added to the raw material containing the biomass powder. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fluidity improver for biomass powder, a molded body using the fluidity improver, and a method for producing the molded body.

  Plastic is relatively easy to mass-produce products having a three-dimensional shape, and is used in many fields. A variety of molding techniques and molding apparatuses have been developed. However, most plastics are serious problems because they are not easily decomposed in nature and have a large environmental load. Furthermore, if you continue to use plastics made from petroleum, which is a fossil resource, not only will you run out of oil, but carbon dioxide will be generated when you dispose of it. It is said to be a threat to global warming and the future maintenance of the global environment.

  One way to deal with this is the development of biodegradable plastics using biomass-based raw materials. Biodegradable plastics can be recycled in the carbon ecosystem, and sustainable production is said not to increase carbon dioxide. Typical biodegradable plastics are those in which starch contained in plant materials such as corn and sweet potato is converted to lactic acid by yeast, and lactic acid is converted to lactic acid based plastic. If lactic acid can be obtained, lactic acid-based plastics can use plastic production technology and molding technology developed with conventional petroleum-based plastics, and can produce products that are biodegradable and have a low environmental impact. .

  Lactic acid-based plastics are inferior in terms of production costs compared to current petroleum-based plastics, and production is limited at present. In the future, with environmental problems and rising oil supply prices, lactic acid-based plastics made from plants are expected to expand the practical field. However, since lactic acid plastics are made from starch, high starchy plants such as corn and sweet potato are required, but in most cases, high starchy plants are edible plants, and petroleum-based plastics If you try to produce in large quantities, there is a risk of affecting food supply.

  On the other hand, processing technology using woody biomass as a material has existed for a long time, and the desired shape has been obtained by methods such as “cut”, “shave” and “join”. In addition, wood-based boards made from wood chips, wood flour, wood fibers, etc. have been put into practical use. For example, there are a fiber board and a particle board. The particle board is a board obtained by mixing a wood chip or wood powder with a binder and heat compression molding, and is used for building materials and furniture. Generally, woody biomass is used as a material after being processed from a log state into a plate or pillar material, or after being molded as the woody board, and is further cut, cut, and joined. It becomes the shape of the product through such processing. Like plastic products, it is not easy to manufacture products with complicated three-dimensional shapes from raw materials.

  Therefore, a technique for manufacturing a product having an arbitrary three-dimensional shape, such as a plastic molded product, using a biomass-based material as it is as a raw material has been studied. Patent Document 1 discloses a technique for manufacturing an extruded product or an injection-molded product from a raw material in which a fine powdery wood material, a molten mixed resin such as maleic acid-modified resin, and a spherical material such as silica fume or fly ash are mixed. Has been. In this technology, the melt-mixed resin imparts fluidity to the finely divided woody material, and the finely divided spherical material further improves the fluidity of the finely powdered wooden material. Has improved moldability.

  In Patent Document 2, instead of a method in which formaldehyde-based binder resin is mixed into wood chips such as sawdust and sawdust to make the raw material fluid and pressure-molded, wood powder, sawdust, sawdust, wood chips, etc. There has been proposed a molding method in which lignin in raw material wood is used as a binder by enclosing wood chips together with a water-based binder in a mold and heating and pressing. By using lignin in raw material wood, it is not necessary to use a binder that generates formaldehyde, which has been used in the past, and it is said that a compact shaped product that does not affect the human body can be manufactured at low cost. Yes.

  In Patent Document 3, a biomass-based material powder is heated and pressurized to produce a hemicellulose pyrolysis fluidized product, and the fluidity of the biomass-based material powder by this hemicellulose pyrolysis fluidized product is used to resemble plastic. A molding method for manufacturing a molded product has been proposed. For example, it is disclosed that when bamboo powder is used as biomass-based material powder, the bamboo powder is fluidized by a heat and pressure treatment for 20 to 40 minutes.

In Patent Document 4, the biomass-based material is fluidized by heating and pressurizing the biomass-based material without pulverizing the biomass-based material to produce an extrusion-molded product or an injection-molded product having plastic-like fibers. Technology is disclosed. It is thought that the idea similar to Patent Document 3 was developed.
JP 2004-230663 A JP 2007-044966 A JP 2006-123443 A JP 2006-247974 A

  As described above, the development of biomass-based molded products that are replacing plastic-based molded products having many problems such as resource problems, waste problems, and global environmental problems is underway. However, the molding method described in Patent Document 1 requires several tens of percent of a petroleum-based resin for melting, and is considered not to be a fundamental solution for resource problems, waste problems, global environmental problems, and the like. The molded article described in Patent Document 2 is not suitable for mass production because it is batch press molding.

  Since the molded bodies described in Patent Documents 3 and 4 are fluidized by heating and pressurizing biomass-based raw materials and introduced into a mold and molded, it is considered that injection molding is possible. However, it is considered that there is a large variation in the amount and time for generating the fluidized hemicellulose depending on the type of raw material powder. When the raw material is wood flour, it is considered that a relatively high temperature of 220 to 240 ° C. is necessary to decompose hemicellulose to produce a hemicellulose fluidized product. Further, it takes time to produce a fluidized hemicellulose, and according to the study by the present inventors, in order to produce a fluidized hemicellulose in a low temperature region of about 200 ° C., the wood flour is about four times as long as the bamboo flour. Was necessary.

  An object of the present invention is to provide a biomass-based fluidity improver capable of obtaining a biomass-based molding raw material having fluidity even at a low temperature, and a molded body using the same and a method for producing the molded body, in view of the above problems It is to be.

  The present invention is a fluidity improver for improving the fluidity of biomass-based powder, characterized by comprising a hot water extract obtained by subjecting bamboo to hot water extraction treatment, preferably the hot water extraction The treatment is the fluidity improver obtained by evaporating the liquid after extracting with hot water at 60 to 180 ° C. and normal pressure to 2 MPa for 10 seconds or more.

  The present invention is a molded body characterized in that the fluidity improver is added to a raw material containing biomass-based powder, and then molded by heating and pressurizing. Preferably, the biomass-based powder is It is the said molded object characterized by being a wood powder or a bamboo powder.

  The present invention includes a heating step of heating a forming raw material containing biomass powder and the fluidity improver to form a fluid, a forming step of forming the fluid to form a thermoformed body, and the heating And a cooling step of cooling the molded body to form a molded body, and preferably, the molded body is molded at a molding temperature of 150 to 250 ° C. It is a manufacturing method.

  The present invention is a method for producing a molded body characterized by producing a molded body by injection molding or extrusion molding a biomass-based powder and a molding raw material containing the fluidity improver, preferably, It is the manufacturing method of the said molded object characterized by shape | molding at the shaping | molding temperature of 150-250 degreeC.

  INDUSTRIAL APPLICABILITY The present invention can provide a biomass-derived fluidity improver for obtaining a biomass-based forming raw material having fluidity even in a relatively low temperature range, a molded body using the same, and a method for producing the molded body.

  The fluidity improver of the present invention is a fluidity improver containing a hot water extract obtained by subjecting bamboo material to a hot water extraction treatment, and is characterized by improving the fluidity of biomass powder. The type of bamboo that is the raw material of the bamboo is not particularly limited, but it is preferable to use Moso bamboo, mushroom, or bee that grows large and is generally used as bamboo.

  As shown in FIG. 1, the fluidity improver of the present invention may be obtained by extracting an active ingredient from bamboo with hot water. In the hot water extraction treatment of bamboo material, it is preferable to extract the bamboo material that has been pulverized and easily extracted with hot water at 60 to 180 ° C. and normal pressure to 2 MPa for 10 seconds or more. As the hot water extraction temperature is higher, the extraction speed is faster and the productivity is higher. However, when the hot water extraction temperature exceeds 100 ° C., a pressurizing device is required, and the device becomes large. The hot water extract is dried after removing moisture, and becomes the fluidity improver of the present invention. When the hot water extract is coarsened during drying, the coarse hot water extract is preferably pulverized and powdered to obtain the fluidity improver of the present invention.

  An experiment was conducted to examine the fluidity of the mixture of hot water extract and biomass powder in the present invention. A capillary rheometer type fluidity evaluation apparatus as shown in FIG. 2 is filled with dry bamboo powder (also called whole dry bamboo powder) that has passed through a 200-mesh sieve, heated to 200 ° C., and compressed by a piston at 142 MPa. did. FIG. 3 shows the change over time of the piston position when all dry bamboo powder is compressed. At the beginning of compression, the piston was about 5 mm high, but the whole dry bamboo powder began to flow in 2 to 3 minutes due to heating and compression, and it flowed out from the lower capillary, almost out in about 30 minutes. Reached the lowest point.

  Next, after extracting the above-mentioned completely dried bamboo powder with hot water at 90 to 98 ° C. for 2 hours, the extraction residue (hereinafter referred to as bamboo powder after extraction) is dried, and this extracted bamboo powder is the same as described above. An experiment was conducted to check the fluidity. As a result, as shown in the graph of FIG. 3, the bamboo powder after extraction hardly flowed for about 50 minutes, and then fluidized in 70 minutes up to 120 minutes and flowed out of the capillary.

  From these two experimental results, it is considered that the hot water extract in bamboo powder (referred to as bamboo hot water extract) has an effect on the promotion of fluidization of bamboo powder. On the other hand, in order to grasp the thermal decomposition behavior of each material, thermogravimetric measurement (TG) was performed on all dry bamboo powder, bamboo hot water extract, and bamboo powder after extraction. The result is shown in the graph of FIG. Bamboo hot water extract begins to lose weight at around 140 ° C., 10% at 180 ° C., 20% at 220 ° C., and further at a similar rate. On the other hand, the weight of bamboo powder after extraction hardly decreases, the weight hardly changes up to 200 ° C., and the weight decreases only 10% even at 250 ° C. The weight loss of all dry bamboo powder was intermediate between the bamboo hot water extract and the bamboo powder after extraction, which was relatively close to the result of bamboo powder after extraction.

  From these results, it is suggested that the thermally decomposable substance in the bamboo hot water extract affects the fluidity of bamboo powder. The present inventors presume that the mechanism by which bamboo hot water extract improves fluidity is as follows. A pyrolyzate is generated from the bamboo hot water extract heated to 200 ° C., but in a high pressure state of 142 MPa, the pyrolyzate cannot be kept in a gas state but becomes a liquid, or a fluid in a critical state And diffuses into the pressurized sealed space. It is considered that the presence of a diffused liquid or a fluid in a critical state between the bamboo powders serves as a lubricant and facilitates the flow of the bamboo powder.

  The molded body of the present invention is characterized in that the above-described fluidity improver is added to a raw material containing biomass-based powder, and is molded by heating and pressing. The fluidity improving effect of the bamboo hot water extract described above is effective not only for bamboo powder but also for various powders, and can be applied to all biomass powders. Examples of the biomass powder in the present invention include wood powder, bamboo powder, and grass powder. Among these, wood powder and bamboo powder are preferable because of easy availability of raw materials. These biomass powders are preferably dried powders, and the average particle diameter of the powders is not particularly limited, but is 1000 μm or less, preferably 500 μm or less, more preferably 200 μm or less. It is desirable. Furthermore, there is no problem even if the powder contains a chip of about several centimeters in size, but it is better to remove it as much as possible.

  The method for producing a molded body of the present invention includes a heating step of heating a molding raw material including a biomass powder and a hot water extract obtained by subjecting bamboo to hot water extraction, It includes a molding step of forming a body to form a thermoformed body, and a cooling step of cooling the thermoformed body to form a molded body. As the biomass powder, the powder already described is used. In the heating step, it is preferable to heat while applying pressure, and the heating temperature is 150 to 250 ° C., preferably 180 to 200 ° C., and the pressing condition is 10 to 500 MPa, preferably 80 to 200 MPa. desirable. The molding process only needs to have sufficient time for the fluid to be sufficiently filled in the mold, and the mold is preferably the same as the heating temperature of the heating process or lower by about 5 to 10 ° C. In the cooling step, the mold is preferably cooled with cooling water or the like, and may be allowed to cool until the thermoformed body is solidified. When the thermoformed body in the mold is cooled and becomes a solidified molded body, it may be taken out from the mold.

  As a method for producing a molded article according to the present invention, a molded article containing a hot powder extracted from a biomass powder and a hot water extract obtained by subjecting bamboo to hot water is produced by injection molding or extrusion molding. It is characterized by. The injection molding or extrusion molding may be performed following the normal injection molding or extrusion molding of petroleum-based plastics. Moreover, you may follow the above-mentioned heating process, a shaping | molding process, and a cooling process using the press molding machine, injection molding machine, or extrusion molding machine of a petroleum-type plastic.

  As a method for producing a molded body of the present invention, biomass chips and fibers may be mixed in addition to powder as a biomass raw material. For example, wastes such as bamboo chips, wood chips, sawdust, straw scraps, rice husks, kenaf, and cotton scraps can be used.

(Comparative example)
The chip-shaped cedar material was pulverized with a pulverizer using a circular saw, dried at 105 ° C., and passed through a 200-mesh sieve to remove coarse powder to produce whole dry wood flour. The whole dry wood powder was used as a standard sample, filled in a high-pressure fluidity evaluation apparatus as shown in FIG. 2, heated to 200 ° C. and compressed with a piston pressure of 142 MPa, and the change with time was observed.

  FIG. 5 shows the change over time of the piston position during compression by the apparatus for evaluating the fluidity of all dry wood flour. The piston position was lowered by about 0.5 mm at the beginning of compression, but it is considered to be due to the effect that the filling state was not sufficient. After the piston pressure reaches normal pressure, the piston height is about 4.5 mm, but the whole dry wood powder begins to fluidize slowly by heating and compression and flows out from the lower capillary, about 30 mm. About 10% by mass flowed out in about 60 minutes, about 30% by mass flowed out in 60 minutes, about 50% by mass flowed out in 75 minutes, and it took 120 minutes or more to completely flow out.

(Example)
A bamboo hot water extract was obtained by the production process shown in FIG. First, a 2 to 3 year old moso-chiku is cut into chips (saw cutting process), this chip is pulverized with a pulverizer using a circular saw (crushing process), dried at 105 ° C., and further 200 mesh (about approx. All dry bamboo powder was produced by removing the coarse powder (classifying step). The whole dry bamboo powder was subjected to hot water extraction at 100 ° C. for 30 minutes, and then the extraction residue (bamboo powder after extraction) was removed to obtain a bamboo hot water extract solution (hot water extraction step). Water was removed from the hot water extract solution (concentration step) and dried at 105 ° C. to obtain a bamboo hot water extract. The yield of the bamboo hot water extract based on the total dry bamboo powder was 5% by mass. This bamboo hot water extract is the fluidity improver of the present invention.

  A mixed wood flour obtained by mixing 10% by mass of bamboo hot water extract with all dry wood flour, which is a standard sample prepared by the same method as in the comparative example, is filled in a fluidity evaluation apparatus as shown in FIG. And compressed with a piston pressure of 142 MPa. A mold having a gear-shaped cavity was set at the capillary outlet portion of the fluidity evaluation apparatus so that the effluent flowing out from the capillary was filled.

  FIG. 5 shows the change over time of the piston position when the mixed wood flour is compressed. At the beginning of compression, the piston was about 5 mm in height, but mixed wood powder started to flow in 2 to 3 minutes by heating and compression, and flowed out from the lower capillary, and about 50% by mass flowed out in about 15 minutes. , About 95% by mass flowed out in 30 minutes, almost all flowed out in 60 minutes, and the piston reached the lowest point. Further, a gear-shaped molded product as shown in FIG. 6 was formed on the mold set in the lower part of the fluidity evaluation apparatus. This can be said to be a kind of injection molded product.

  As can be seen from the results shown in FIG. 5, the fluidization phenomenon occurs only with all dry wood powder, and it is considered that even if it is a long dry wood, it can be molded even with all dry wood powder. However, when the examples and the comparative examples are compared, the fluidization of the mixed wood flour is clearly fast, and the fluidization of the whole dry wood flour is slow. That is, it can be seen that, in extrusion molding, injection molding, and press molding, the moldability of mixed wood powder is better than that of all dry wood powder.

  The present invention makes it possible to produce a molded product in place of a plastic product by using biomass-based powders, particularly wood-based waste materials and scraps generated in large quantities. Furthermore, since a hot water extract from bamboo is used as a fluidity improver for molding, it leads to effective use of bamboo and contributes to reduction of environmental burden.

Image of manufacturing process of bamboo hot water extract from bamboo Schematic diagram of fluidity evaluation equipment (extruder, press) Fluidity test results of all dry bamboo powder and bamboo powder after hot water extraction Thermogravimetric measurement results of all dry bamboo powder, bamboo hot water extract, and bamboo powder after hot water extraction Fluidity test results of whole dry wood flour and mixed wood flour with added fluidity improver of the present invention A molded body of mixed wood powder to which the fluidity improver of the present invention is added

Claims (7)

  A fluidity improver that improves the fluidity of a biomass-based powder, comprising a hot water extract obtained by subjecting bamboo to a hot water extraction treatment.   The fluidity improver according to claim 1, wherein the hot water extraction treatment is a treatment of extracting for 10 seconds or more with hot water at 60 to 180 ° C and normal pressure to 2 MPa.   A molded article obtained by adding the fluidity improver according to claim 1 or 2 to a raw material containing biomass powder and heating and pressurizing the molded article.   The molded body according to claim 3, wherein the biomass-based powder is wood powder or bamboo powder.   A heating step of heating a forming raw material containing the biomass-based powder and the fluidity improver according to claim 1 or 2 to make it an easy fluid, and thermoforming the easily fluid to make a thermoformed body The manufacturing method of the molded object characterized by including the shaping | molding process and the cooling process which cools the said thermoformed body and makes it a molded object.   A method for producing a molded article, comprising producing a molded article by injection molding or extrusion molding a biomass-based powder and a molding raw material containing the fluidity improver according to claim 1 or 2.   It shape | molds at the shaping | molding temperature of 150-250 degreeC, The manufacturing method of the molded object of Claim 5 or 6 characterized by the above-mentioned.