KR20090037810A - Method for producing woody formed article and woody formed article - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the resination of wood-based materials, and relates to a method for producing wood-molded bodies, and a molded article, which are characterized by reducing the odor, which is the problem of resinization of wood-based materials, and reducing the water absorption.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a wood molded body for molding the wood-based material by expressing the adhesiveness and thermal fluidity of wood, and to a wood molded body. After adjusting the water content of the wood-based material, the heated water vapor is applied to the wood tissue. By performing the steam treatment to be brought into contact, the absorption rate is lowered, and the odor generated from formic acid and acetic acid can be significantly reduced.

Description

METHOD FOR PRODUCING WOODY FORMED ARTICLE AND WOODY FORMED ARTICLE

The present invention relates to the resination of wood-based materials, and relates to a method for producing a wood molding and a wood molding, characterized by reducing the odor which is a problem of resinization of wood-based materials and reducing the absorption rate.

More specifically, after adjusting the moisture content of the wood-based material, by heating the steam to contact the wood tissue to express the adhesiveness and thermal fluidity of the wood, and to produce the wood moldings obtained by molding the wood-based material and wood moldings The present invention relates to a method for producing a wood-based molded article and a wood-molded article having a low water absorption and a very low odor generated from organic acids such as formic acid and acetic acid and a very low emission of formaldehyde of organic compounds.

Attempts have been made to use wood as an alternative to plastics and metals. For example, Patent Document 1 discloses a method for producing a molded body that is molded by pressing while heating a wood-based material containing ligunin, hemicellulose, and cellulose after being steamed (hereinafter, referred to as 'vapor treatment'). . According to the said molded object, it is possible to replace the various products which were conventionally shape | molded by metal, plastic, etc. with wood-based material.

More specifically, it becomes possible to manufacture various products, such as tableware, accessories, furniture, building materials, electronic products, etc., using a natural wood type material, without using plastic. (Patent document 1)

In addition, by heating the molding composition comprising the lignocellulosic material obtained by increasing the lignocellulosic-containing material by drying, heating the molding material to impart a shape, the fluidity of the wood material is realized in a nearly perfect form. Has been proposed. (Patent Document 2)

[Patent Document 1] Japanese Patent Application Laid-Open No. 2004-261967

[Patent Document 2] Japanese Unexamined Patent Publication No. 2003-165844

On the other hand, molded articles made of wood-based materials subjected to steam treatment have high absorption rates of 4% to 8% in a 24-hour deposition treatment test, so that when used as a mechanical part, it is a problem in terms of durability. Ham is strongly desired. In addition, wood is decomposed when the wood-based material is steamed to produce formic acid, acetic acid, etc., so that a strong odor occurs when the molded body is heated and pressurized.

Although it is considered to apply a protective paint such as varnish as a solution to such an odor, a protective paint such as varnish is manufactured with chemical components such as synthetic resins and organic solvents as main components. Therefore, in order to realize a better product in terms of global environment, it is a material that should be avoided. In addition, when the varnish is applied to increase the manufacturing cost of the product increases the manufacturing cost. For this reason, there is a strong demand for the emergence of a technology capable of lowering the smell while lowering the absorption rate without applying varnish.

Accordingly, an object of the present invention is to provide a molded article and a method for producing the molded article which are made of a wood-based material with reduced water absorption and odor.

The inventors of the present invention have diligently studied to adjust the water content of the wood prior to steaming to improve the penetration of the heated steam into the wood tissue, thereby reducing the number of free water which promotes the decomposition of hemicellulose and lignin having a relatively low decomposition temperature. It has been found that the absorptivity of the molded body can be improved.

When the wood-based material before steaming contains a large amount of free water, the free water becomes steam by the steaming process, and the wood-based material penetrates into the wood-based material, which excessively decomposes or spills cellulose, lignin, and hemicellulose. There is a fear that the adhesion and fluidity imparting effect of lignin or hemicellulose may be impaired. Therefore, it was found that such adverse situation is suppressed by adjusting the moisture content of the wood-based material before the steaming treatment. In addition, by adjusting the moisture content, it is possible to reduce the thermal decomposition of cellulose or lignin by heating at the time of manufacturing the molded product, and to suppress the formic acid, acetic acid, and formaldehyde generated by the decomposition of hemicellulose or cellulose, thereby lowering the odor of wood moldings. Found.

The present invention is to solve the above conventional problem, and is made as follows.

The method for producing a wood molded body according to claim 1 includes a process for increasing the moisture content by drying the wood-based material and adjusting the water content, and a process for increasing the water content of the wood-based material adjusted by the water content adjustment process; And a molding step of molding the wood-based material subjected to the increase treatment by the increase step.

The method for producing a wood molded article according to claim 2 is the method for producing a wood molded article according to claim 1, wherein the step before adjusting the steam is characterized in that the water content of the wood-based material is adjusted to 20% or less.

The manufacturing method of the wood molding of Claim 3 is a manufacturing method of the wood molding of Claim 1 or 2 WHEREIN: The said shaping | molding process is a temporary shaping | molding process of temporarily forming the wood-based material which was steamed by the said steaming process, And a main molding step of compression molding the molded article formed by the temporary molding step, wherein the wood-based material is dried after at least one of the temporary molding step and the main molding step after the increase process. It characterized in that it comprises a drying step before molding to adjust.

At this time, "drying the wood-based material before at least one of the caustic molding process or the main molding process" of course includes drying the wood-based material only before any one of the caustic molding process and the main molding process. Now, it is also meant to include the drying of the wood-based material before both processes between the temporary molding process and the main molding process.

The manufacturing method of the wood molding of Claim 4 is a manufacturing method of the wood molding of Claim 3, Comprising: When the said drying process before shaping | molding is performed before the grinding | pulverizing process which grinds a wood-based material as before the said shaping | molding process, The moisture content of the system material is dried to 15% or less, and when performed before the main molding step, the pseudo-molded body made of the wood-based material is dried to 2% or less of water content.

The manufacturing method of the wood molding of Claim 5 is a manufacturing method of the wood molding of Claim 3 or 4 WHEREIN: The said shaping | molding process is filled with wood-based material in a metal mold | die, and press-molded to 1 MPa or more and 20 MPa or less, and shape | molding a molded object. Characterized in that.

The manufacturing method of the wood molding of Claim 6 is a manufacturing method of the wood molding of Claim 1 by the said steaming process so that a thermoplastic resin may be contained in the ratio of 5 weight part or more and 35 weight part or less with respect to 100 weight part of molding materials. And a resin addition step of adding the thermoplastic resin to the steamed wood-based material to obtain the molding material, wherein the molding step is to inject the molding into the mold by injecting the molding material obtained by the resin-adding step into the mold. It features.

The method for producing a wood molded body according to claim 7 is the method for producing a wood molded body according to any one of claims 1 to 6, wherein the process of increasing the wood-based material from the upper opening of the container having a breathable side surface. To the wood-based material introduced into the container, the cross section orthogonal to the longitudinal direction of the elongated horizontal member placed between the side surfaces in the container with respect to the opening above the container. The wood-based material is introduced into the container in a state of being installed in the container in the form of a protruding mountain shape and an open shape toward the bottom of the container.

The method for producing a wood molded body according to claim 8 is a method for producing a wood molded body by contacting the wood-based material with water vapor and imparting thermal fluidity to the wood-based material, wherein the wood-based material is subjected to steam treatment, molding, and main molding. In shaping, the water content of the shaping wood-based material is adjusted by shaping before the steam treatment and before shaping of the caustic or main shaping.

The manufacturing method of the wood molding of Claim 9 is the manufacturing method of the wood molding of Claim 8 WHEREIN: After adjusting the moisture content of a wood-based material to 3% or more and 20% or less, after contacting water vapor, the water content of the wood-based material is adjusted. It is characterized in that the molded product obtained by drying to 5% or more and 15% or less to prepare a pseudo-molded product is dried to a moisture content of 2% or less and then compression molded.

The manufacturing method of the wood molding of Claim 10 is a manufacturing method of the wood molding of Claim 8 or 9 WHEREIN: The moisture content of a wood type material is adjusted to 5% or more and 15% or less, it fills in a metal mold, and it is 1 MPa or more and 20 MPa or less The molded article is molded by pressing.

The wood molding according to claim 11 is produced by contacting the wood-based material with water vapor and imparting fluidity to the wood-based material, and is formed by steam treatment, caustic molding, and main molding of the wood-based material. The water content of the free material and the bound water of the system material is adjusted by shaping the mold before forming the dummy mold or the main mold. At this time, "adjusting the moisture content of free water and bonding water of a wood-based material before pre-molding or before shaping | molding of main molding" means that the water content of water in the wood-based material including free water and bonding water before or after molding. It means to adjust before shaping | molding of shaping | molding.

According to the method for producing a wood molding according to claim 1, the wood molding is dried and the water content is adjusted to increase the wood-based material. Thus, the wood molding is reduced in absorption and odor without applying a protective paint such as varnish. There is an effect that it is possible to provide.

According to the manufacturing method of the wood molding of Claim 2, in addition to the effect by the manufacturing method of the wood molding of Claim 1, water absorption and an odor are further reduced by adjusting the moisture content of wood-based material to 20% or less by a pre-magnification adjustment process. There is an effect that can provide a wood molding. Since the equilibrium moisture content of the wood (i.e., the water content of only bound water) is 15%, the free water can be made 5% or less by adjusting the water content to 20% or less, which has a much higher effect on the improvement of absorption and odor. Will be obtained.

According to the manufacturing method of the wood molding of Claim 3, in addition to the effect by the manufacturing method of the wood molding of Claim 1 or 2, there exists an effect of being able to shorten the time required for shaping | molding, and to produce. Originally, the wood-based material is lower in thermal conductivity and further lower in thermal conductivity because the wood-based material contains a large amount of air when the wood-based material is composed of wood powder. For that reason, it takes time to apply the wood-based material as a molding material to a uniform temperature. Therefore, first, the pseudo-molded body is formed by the pseudo-molding process to densify the wood-based material. Caustic molding can be molded at room temperature, so heating does not require the main molding, the heating time is shortened and the working efficiency is good.

In addition, when a large amount of binding water is present in the wood-based material, moisture may vaporize from the inside of the wood-based material during compression molding of the wood-based material, thereby causing a defect such as dirtying the surface of the molded body or cracking in the molded body. Therefore, there is an effect that it is possible to suppress vaporization of water in compression molding and obtain a good molded body by drying the wood-based material before at least one of the temporary molding process or the main molding process.

On the other hand, after the preliminary molding, in the case of performing the pre-molding drying process before the main molding, if the main molding is carried out sequentially after forming a large number of the molded articles and drying them all at once, the work can be efficiently performed.

According to the method for producing a wood molding according to claim 4, in addition to the effect according to the method for manufacturing a wood molding according to claim 3, the wood-based material is pulverized by drying the water content of the wood-based material before grinding before the molding to 15% or less. There is an effect that can be prevented from filling the mesh. The high moisture content of the wood-based materials makes it easier to fill the mesh of the grinder.

In addition, the temporary molded object may expand due to stress when it is separated from the mold after the temporary molding. If the pseudo-molded product is dried to a moisture content of 2% or less by the pre-molding drying process before the main molding process, the pseudo-molded body shrinks due to drying, so that it is possible to accommodate the pseudo-molded body in the mold for main molding. . In addition, there is an effect that a good quality molding material can be obtained by reliably suppressing vaporization of water during compression molding.

According to the manufacturing method of the wood molding according to claim 5, the effect exerted in the method of manufacturing the wood molding according to claim 3 or 4 is added, and the molding is performed by pressing the wood-based material at 1 MPa or more in the molding process. Therefore, there is an effect that the wood-based materials can be mutually bonded to such an extent that a pseudo-molded body is formed while maintaining a predetermined shape even at room temperature. In addition, by pressing the wood-based material under 20 MPa or less, it is possible to suppress the pressurization more than necessary. By pressurizing to about 20 MPa, the wood-based material is compressed to a density of about 1.45 g / cm, which is called the true density of the wood (the density when there is no void). Therefore, even if more pressure is applied, it becomes difficult to change the density.

According to the manufacturing method of the wood molding of Claim 6, in addition to the effect by the manufacturing method of the wood molding of Claim 1, there exists an effect that it is possible to shape a wood molding by injection molding. When the amount of the thermoplastic resin is 5 parts by weight or more based on 100 parts by weight of the molding material, the flow effect of the thermoplastic resin is added to the flow effect of the lignin or hemicellulose, so that the molding material has sufficient fluidity. Injection molding is possible. In addition, it is possible to suppress the amount of the resin material used by keeping the amount of the thermoplastic resin at 35 parts by weight or less. At present, since the exhaustion of the reserve resources is serious, it is desirable to suppress the content of the resin that uses the reserve resources as a raw material.

According to the manufacturing method of the wood molding of Claim 7, in addition to the effect by the manufacturing method of any one of Claims 1-6, there exists an effect that the efficiency of a steaming process can be improved. The transverse member is provided in the container in the direction in which the cross section orthogonal to the longitudinal direction forms a mountain shape projecting with respect to the opening part above the container. Therefore, the wood-based material introduced from the opening in the upper part of the container flows on both sides of the cross member by the inclined surface of the cross member, so that a gap is formed in the top of the cross member even after the wood material is deposited. Accordingly, in the increase process, the calculated portion of the transverse member provided on both sides having air permeability functions as a steam cylinder. However, since the transverse member has an open shape toward the lower side, it is possible to make the wood-based material in the container directly contact the steam passing through the transverse member.

According to the manufacturing method of the wood molding according to Claims 8 to 10, or the wood molding according to Claim 11, in the case of producing a molded article made of wood-based material, the moisture content before steam treatment of the wood-based material without coating the protective paint such as varnish It is possible to adjust the moisture content of the wood prior to forming the molded article, and can provide a molded article which reduces the absorption rate and smell of the molded article.

1 is a flowchart showing a method for producing a molded article of the present invention.

Figure 2 (a) is a perspective view showing a state of use of the ventilation aids mounted on the raw material container (C), (b) is a front view of the ventilation aids, (c) is a side view of the ventilation aids.

FIG. 3 (a) is a graph showing the relationship between the water content of the wood-based material before steaming and the water absorption of the wood-based molded product as a result of the absorption test of Experiment 2. FIG. (b) is a graph showing the results of the absorption test on the wooden molded body when the molding temperature is 210 ° C.

4 is a graph showing the relationship between the water content of the wood-based material before molding, the wood molded body, and the water absorption rate and the expansion ratio of the wood molded body.

((Explanation of symbols for main parts of drawing))

P2. Water content adjustment process before increase in steam (an example of increase process before increase in steam)

P3. Capital increase process

P4. Hygroscopicity Control Process

P6. Molding Process

P7. Water content adjustment process before forming

P8. Main molding process

C. Raw material container (an example of container)

14. Lateral member

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a process diagram showing a first embodiment of a method for producing a wood molded product of the present invention, which is a process chart when a wood molded product is produced by compression molding.

In the preparation step P1 of the wood-based material, the wood-based material is prepared. "Wood-based material" according to the present invention means all the lignocellulosic materials derived from plants, for example, refers to lignocellulosic including lignin, hemicellulose and cellulose. In such wood-based materials, the word "wood" is not limited to wood, but can also be taken from herbaceous plants. Such wood-based materials can be collected from various trees such as cedar, hinoki and beech. It is also possible to collect from herbals such as kenaf, corn, sugar cane, hemp, ripple, rice and the like. Alternatively, it can be collected from demolition materials such as dismantled houses, dismantled furniture, wood debris, thin lumber, chaff, old paper, pruned ground, grass, fallen leaves, and sugarcane squeezer (bagas). Do. In addition, the wood-based material can be obtained by mixing high-grade paper containing almost no lignin with lignin discharged as waste in the pulping process. In addition, it is also possible to combine two or more kinds of the wood-based materials.

As the wood-based material used as the raw material in the present invention, it is preferable to use one that has been refined so that it can be brought into uniform contact with water vapor. When the wood-based material is subdivided, not only can it make uniform contact with water vapor during the steam treatment described later, but also it is possible to shorten the time required for the steam treatment for contacting the wood-based material with water vapor. Therefore, it is advantageous to use wood or the like processed in the form of flakes or fine powder as the wood-based material. It is also possible to use sawdust, etc. generated during the cutting process of wood as it is.

In the wood-based material preparation step P1, the water content (dry basis) of the wood-based material prepared from the raw material is preferably 30% or less (hereinafter, the water content means weight%). When the water content exceeds 30%, the decomposition component generated in the wood-based material is easily leaked by the steaming process, and the components necessary for plasticization and fluidization are difficult to be maintained in the wood-based material. In addition, when the water content is high and excessively reacted by the steam treatment, the decomposition of cellulose, etc., causes the generation of organic acids, which gives a strong smell to the molded body. Wood is often left to stand in the air before being sanctioned to prevent cracking and the like so that the water content is less than 30%, the water saturation point of wood fibers. Therefore, the wood chips from the sawmill or woodworking shop are already 30% or less in moisture content, so it is preferable to procure them as such raw materials in the wood-based material preparation step P1.

On the other hand, the moisture content of the wood-based material is a value expressed as a percentage of the water content of the wood-based material as a percentage of the dry mass of the wood-based material [= (water content of the wood-based material). Mass ÷ wood-based material) x 100, for example, it is possible to measure using "heat-drying moisture meter MX-50" (manufactured by A & D Co., Ltd.). In addition, the moisture content mentioned later is also measured using the same apparatus.

The wood-based material can be molded into a predetermined shape by contact with water vapor and compression molding. In addition, wood-based materials are known to express plasticity and fluidity by being heated and compressed after contact with water vapor, and components such as lignin and hemicellulose contained in such wood-based materials are decomposed by steaming. It is considered that lignin and hemicellulose after decomposition dissolve by heating and fluidize in the tissue. By plasticizing and fluidizing the wood-based material, it is possible to mold the wood-based material into various shapes such as plastic injection molding. However, plasticized and fluidized wood materials can express plasticity and fluidity by heating and pressing even once solidified.

Next, the increase before water content adjustment process P2 is demonstrated. The increase in moisture content adjustment step (P2) is a step of drying the prepared wood-based material to adjust the water content to reduce it. The water content can be adjusted at room temperature or even under high temperature. Preferably, the moisture content is dried at high temperature by blowing hot air with a dryer.

It is preferable to adjust so that the moisture content (dry basis) of the wood-based material used as a raw material of a wood molding may be 20% or less in the increase before water content adjustment process (P2). By adjusting the water content of the wood-based material to 20% or less, which is close to 15%, which is the equilibrium water content of the wood (i.e., the water content of only the combined water), the free water can be made 5% or less. A high effect is obtained in the improvement of. This can prevent the steam activated by free water heating in the subsequent steaming step P3 from penetrating into the wood-based material and excessively decomposing hemicellulose or lignin, resulting in wood-based material. It is possible to hold the hemicellulose or lignin in the wood-based material necessary for suppressing the outflow of the decomposed components generated in the process and improving plasticity, fluidization, and hydrophobicity. In addition, by suppressing excessive decomposition of hemicellulose or cellulose by steam activated by heating of free water, organic compounds such as acetic acid and formic acid, and organic compounds such as formaldehyde and the like are suppressed. It is possible to reduce the smell of.

On the other hand, when the moisture content of the wood-based material is adjusted to 15% or less by the increase before water content adjustment step P2, since the free water of the wood-based material becomes zero, a higher effect is obtained.

When the moisture content of the wood-based material is adjusted to 5% or less by, for example, drying at a temperature of 130 ° C. using a jacket type dryer, a very high effect can be obtained in the reduction of water absorption and odor. On the other hand, even if the moisture content of the wood-based material is 0% in the steam increase moisture content adjusting step (P2), it can be assumed that the moisture content of the air is absorbed after being discharged from the dryer to reach a moisture content of 1 to 2% in a short time. Therefore, the target value of the moisture content may be 3% or more in the increase before water content adjustment process P2. If the water content target is more than 3%, it is advantageous to carry out the subsequent treatment in a short time without the need for an expensive dryer configured to isolate the wood-based material from the atmosphere.

Next, the increase process P3 is demonstrated.

In the steaming step P3, in order to produce a wood molded body made of wood-based material, wood-based material as a raw material is brought into contact with water vapor such as saturated steam or heated steam. In the present invention, such treatment is referred to as steam treatment.

Specifically, the steaming treatment P is placed in a pressure resistant container having a pressure resistance, in which the wood-based material whose water content is adjusted in the raw water container is charged into the raw material container through the above-mentioned increase in moisture content adjusting step P2. For example, the steam treatment is performed by providing steam from a supply source such as a boiler.

In such steaming treatment, it is preferable that the steam temperature is in contact with the wood-based material with water vapor of 180 ° C or more and 230 ° C or less. By contacting the wood-based material with water vapor in such a temperature range, it is possible to decompose hemicellulose, lignin and the like contained in the wood-based material.

The steaming process is completed by bringing the steam into contact with the wood-based material for a suitable time (for example, several tens of seconds to several tens of minutes). When the pressure or temperature of the steam is low, it is advantageous to make the contact time between the steam and the wood-based material longer. In addition, when the wood-based material is not broken down, it is more efficient to break it down into crushers or the like.

When the temperature of the steam is 200 ° C. or more and 230 ° C. or less, it is possible to complete the steam treatment by bringing water vapor into contact with the wood-based material for several tens of seconds to about 20 minutes. That is, in order to improve the efficiency of the steam increase treatment, for example, it is preferable to use the ventilation aid 10 described below attached to the raw material container C.

Figure 2 (a) is a perspective view showing a state of use of the ventilation aid (10) mounted on the raw material container (C). As shown in Fig. 2 (a), the raw material container C has a cuboid shape, is opened upward, and the bottom and side surfaces are made of mesh and are breathable. In the cooking process P3, wood-based material is introduced through the upper opening of the raw material container C. Then, the raw material container C is stored in a pressure vessel (not shown), and, for example, steam treatment is performed on the wood-based material in the raw material container C by supplying water vapor from a source such as a boiler. On the other hand, Figure 2 (a) shows a state in which the two air vent aid 10 is mounted on the raw material container (C).

FIG. 2 (b) is a front view of the ventilation aid 10, and FIG. 2 (c) is a front view of the ventilation aid 10. That is, the state seen from the IIb direction shown in Fig. 2A is taken as the front of the ventilation assisting tool 10.

As shown in Fig. 2 (b), the vent aid 10 includes a ladder having a plurality of stage transverse members 14 interposed between a pair of struts 12 and a pair of struts 12. Take form.

The strut 12 has its top bent downward to form a hook 12a. By coupling the pair of hooks 12a to the periphery of the opening M of the raw material container C, the support 12 extends vertically downward along the side inner side of the raw material container C.

The transverse member 14 is a rod-shaped member having a length substantially equal to the distance between opposite sides of the raw material container C, and is vertically coupled to the longitudinal direction of the strut 12 between the pair of struts 12. Therefore, when the ventilation aid 10 is coupled to the raw material container C, the transverse member 14 is constructed in the transverse direction between the side surfaces of the raw material container C. As shown in FIG. As shown in Fig. 2 (c), the transverse member 14 has a cross section orthogonal to the longitudinal direction in the form of a mountain shape protruding with respect to the opening M above the raw material container. It is mounted on. In such a state, when the wood-based material is introduced from the upper side of the raw material container C, the wood-based material flows to both sides of the transverse member 14, and the wood-based material is formed at the mountain bottom under each transverse member 14. Deposition becomes difficult. Thus, a gap is formed between the mountainous portion of each of the transverse members 14 and the stacked wood-based material. As a result, the space at the top of the cross member 14 becomes a passage for steam. In addition, since the transverse member 14 has a shape in which the cross section in the longitudinal direction is open downward, the wood-based material in the raw material container C is brought into contact with the steam passing through the hilltop under the transverse member 14. do. Therefore, it is possible to improve the efficiency of the steaming process P2.

The transverse member 14 is alternately coupled to both sides of the support 12 at equal intervals in the lower direction of the support 12 and the lower direction of the support 12. Thus, by arranging the air passages to every corner, the efficiency of the steaming process P3 can be further improved. That is, in Fig. 2 (c), the inclined surfaces of the transverse members 14 are shown to be parallel, and may be curved.

When finishing the steaming process, it is advantageous to open the raw material container C or the like in which the wood-based material is accommodated, and to expose it under atmospheric pressure. In the case of high pressure steam at or above atmospheric pressure, it is possible to gradually lower the pressure, and at the same time, it is also possible to release the pressure to atmospheric pressure. When releasing to atmospheric pressure at once, the volume of water vapor expands at once inside the tissue of the wood-based material, so that the wood-based material can be pulverized into a fibrous or powdery form (hereinafter, the pressure-based material is released from the high pressure at once. Grinding is called explosives). According to the explosion, the wood-based material can be finely divided and simultaneously subdivided. By subdividing the wood-based material by crushing, the wood-based material can be efficiently dried in a subsequent step.

1, the provisional moisture content adjustment process P4 is demonstrated. Here, the pre-molding moisture content adjusting step P4, the pulverization step P5, the pseudo-molding step P6, and the pre-molding moisture content adjusting step P7 are not essential steps and may be omitted in some cases.

After completion of the steaming treatment in which the wood-based material is brought into contact with water vapor, the wood-based material is dried by the preliminary molding moisture content adjustment step P4 to adjust the water content. Preferably, the wood-based material is dried so that the moisture content is 15% or less. When a large amount of water, particularly binding water, is present in the wood-based material, moisture is vaporized from the inside of the wood-based material during compression molding of the wood-based material, resulting in a problem such as dirtying the surface of the molded body or cracking in the molded body. On the other hand, the target value of the moisture content may be 3% or more in the pseudo-molding moisture content adjustment step P4. In this case, an expensive dryer configured to separate the wood-based material from the atmosphere is not required.

Next, the grinding step P5 will be described.

It is preferable to carry out the process (grinding process) which grind | pulverizes again finely as needed after drying the wood-based material which completed the steaming process by the water content adjustment process P4 before shaping | molding. The grinding step P5 may be omitted in some cases, so that the fluidity and plasticity can be easily expressed when the wood-based material is pressed while heating the wood-based material by pulverizing and minimizing the wood-based material. In order to grind the wood-based material subjected to the steam treatment, it is possible to use grinding means such as a weary mill, a ball mill, a crusher, a mixer, and the like.

On the other hand, in the present embodiment, a method for producing a wood molded body by compression molding a wood-based material is described. In some cases, in the case of performing extrusion molding or injection molding using a wood-based material after grinding, The particle size of the wood-based material is preferably 800 µm or less, more preferably 200 µm or less, in consideration of melt flow for extrusion molding or injection molding.

Next, the provisional molding step P6 will be described.

In the caustic molding step (P6), after the wood-based material is steamed up, the wood-based material is temporarily molded to prepare a caustic body. In this way, the steamed wood-based material is temporarily molded to such an extent that it can have a predetermined shape. In order to "temporally mold" the wood-based material, it is preferable to compress the wood-based material by a press or the like. For example, it is possible to compress the wood-based material subjected to steaming using a mold.

In the caustic molding process, the pressure conditions are preferably 1.0 Mpa or more and 20 Mpa or less. By compression molding the wood-based material at a pressure of 1.0 MPa or more, the wood-based materials can be bonded to each other to maintain a predetermined formation. In addition, by maintaining the pressure at 20 MPa or less, no pressure is applied. More preferable pressure conditions are 1.5 MPa or more and 8 MPa or less. Under such conditions, it is possible to temporarily mold the wood-based material at a more appropriate pressure.

Wood-based materials contain low amounts of air and therefore have low thermal conductivity. Therefore, attempting to compression molded the molded body while heating the wood-based material takes time until the wood-based material reaches a moldable temperature. Therefore, in this embodiment, the provisional molding step P6 is provided before the main molding step P8 to perform the temporary molding at room temperature to reduce the volume of the wood-based material while consolidating and then performing the main molding to achieve thermal conductivity efficiency. In addition, the molding time is reduced.

Since the caustic body can be manufactured at room temperature, it is not necessary to heat the wood-based material. However, it is also preferable to add a small amount of thermosetting resin to the wood-based material as needed before adding the wood-based material to the wood-based material, or to compress the molded body by heating the wood-based material with heating if necessary. . As for the heating temperature, 80 degreeC or more and 120 degrees C or less are suitable.

Next, the pre-molding moisture content adjusting step P7 will be described.

In the preliminary molding moisture content adjusting step (P7), the water content (dry basis) of the wood-based material becomes 2% or less, preferably 1% or less, by using a dryer before charging the molded product into the main mold. It is a process of drying until it adjusts to the moisture content.

In this process, it is preferable to use a dehumidifying dryer and a mechanism for directly supplying the molded body by connecting the dehumidifying dryer to the molding machine with an air hose in order to maintain the moisture content of the molded product at or below a predetermined value.

In this way, even when the caustic body is taken out from the mold, the caustic body can be made small by removing water even if it expands due to stress, and the caustic body can be charged into the mold in the subsequent main molding step.

Next, the main molding step (P8) for compression molding the molded object will be described.

In order to carry out the main molded article, it is advantageous to compress the molded article using a press machine or the like. For example, it is possible to insert a pseudo molded object into the inside of a metal mold | die, and to press this pseudo molded object with high pressure, and to produce this molded object.

In such a molded article, it is possible to perform compression molding while heating the dummy molded article as necessary.

The pressure conditions at the time of compression molding a pseudo molded object in this shaping | molding process P8 are 10.0 Mpa or more and 40.0 Mpa or less. In addition, the heating conditions in the case of compression shaping | molding while heating a provisional molded object are 160 degreeC or more and 230 degrees C or less. By compression molding the pseudo molded article under such conditions, it is possible to produce a main molded article whose surface is smooth and glossy like plastic.

According to the present invention, a part conventionally formed of metal, engineering plastic, or the like can be replaced with a molded body made of wood-based material. Therefore, it is possible to promote the effective use of waste materials, thinning materials, and the like, which have been conventionally disposed of, and since wood-based materials are biodegradable in the soil, incineration is not necessary, and the effect of reducing carbon dioxide emissions can also be expected.

Next, a second embodiment of the method for producing a wood molded article of the present invention will be described. Since the manufacturing method of the second embodiment is the same as the manufacturing method of the first embodiment until the wood-based material preparation step P1, the increase in water content adjustment process P2, and the increase in water process P3 described with reference to FIG. The description is omitted.

Next, a thermoplastic resin is added to the wood-based material which has been cooked so that the thermoplastic resin is contained at a ratio of 5 parts by weight to 35 parts by weight with respect to 100 parts by weight of the molding material to obtain a molding material (resin addition step). According to such a molding material, the wood-based material may be 65 parts by weight or more and 95 parts by weight or less with respect to 100 parts by weight of the molding material.

When the amount of the thermoplastic resin is 5 parts by weight or more with respect to 100 parts by weight of the molding material, the fluidity of the thermoplastic resin is added to the fluidity obtained from the lignin or hemicellulose, and the molding material has sufficient fluidity. This becomes possible. In addition, it is possible to suppress the amount of the resin material used by keeping the amount of the thermoplastic resin at 35 parts by weight or less. As the thermoplastic resin, for example, olefin resins such as polypropylene and polyethylene, polylactic acid, acrylic resins and thermoplastic elastomers are preferable. In particular, an olefin resin having a molding temperature of about 200 ° C may be usefully used. The wood-based material is fluidized at about 200 ° C. If the heating temperature is higher than this, decomposition gas may be generated and defects may occur in the wood moldings.

On the other hand, it is also advantageous to carry out the water content adjustment step (P4) as shown in Fig. 1 before the resin addition step. In addition, it is also preferable to carry out the grinding step (P5) as shown in Figure 1 before the resin addition step.

Next, the molding material mixed with the thermoplastic resin is solidified and pulverized to form a form that can be introduced into a subsequent injection process. As a form which can be thrown into an injection process, a chip form, a flake form, a pallet form, a tablet form are mentioned, for example. For example, the long side may be formed into a flake shape of 1.5 mm or less, or the long side of a chip shape of 5.0 mm or less, a pallet shape of about 5.0 mm in diameter, or a tablet shape. In addition, a molding material is effective also if it grind | pulverizes again to a fine phase as needed. In the case of partitioning the molding material, for example, grinding means such as a weave mill, a ball mill, a ball mill, a crusher, a mixer, or the like can be used.

Next, an injection molding process (part of the molding process) is performed. In the injection molding process, an injection apparatus is used to plasticize by heating and pressurizing the molding material, and then injection into a mold at a predetermined injection pressure to injection molded a wood molded body. The plunger temperature is 180 ° C, the mold temperature is 100 ° C as an example, and the injection pressure is 16MPa as an example. As an injection molding machine, for example, the HAITIAN HTF-200X 200 ton horizontal injection molding machine may be used.

On the other hand, the preferable molding temperature of molding material is 180 to 230 degreeC. By maintaining at 180 ° C. or higher, the thermal fluidity of the wood-based material is high, so that even a complicated structure can be molded. In addition, by maintaining the temperature at 230 ° C. or lower, it is possible to suppress generation of cracked gas due to decomposition such as hemicellulose and molding defects caused by cracked gas.

The heating temperature can be changed according to the type of wood. For example, the heating temperature at the time of using conifers, such as cedar, as a matrix material (the base material), is suitable in the range of 200 to 210 degreeC. On the other hand, the heating temperature in the case of using hardwoods, such as maple, as a matrix material, is suitable for the range of 180 to 200 degreeC.

According to the manufacturing method of the wood molding according to the second embodiment, the same effects as in the manufacturing method of the first embodiment can be obtained. In other words, the hemicellulose or lignin of the wood is maintained without excessive leakage in the steaming process by going through the steaming before adjusting the water content. Therefore, it is believed that hemicellulose or lignin decomposed by the steam is polymerized by heat and pressure during injection molding to increase hydrophobicity and improve water absorption.

Further, according to the second embodiment, the fluidity can be further increased by mixing the resin, so that even a complicated structure such as a gear can be injection molded into a wood molded body containing a high ratio of wood-based material.

Hereinafter, the Example which actualized this invention further is described. That is, Examples 1 and 2 described below are examples of compression molding of a wood molded body through the entire process except the grinding step P6 in the process shown in FIG. 1. In addition, Examples 3 to 5 is an example of compressing the wood molding through the entire process except for the pre-push moisture content adjusting step (P4) to the molding process (P6) of the process shown in FIG.

(Example 1) First, sawdust which is produced when sawn cedar is produced at a sawmill using wood meal as a wood-based material as a raw material was prepared, and the wood-based material was adjusted to a water content of 12%. Thereafter, the mixture was steamed at 215 ° C. for 6 minutes and dried to obtain 8% water content of wood flour. Subsequently, the inside was molded into a molding mold having a diameter of 140 mm and compression molded at a pressure of 20 MPa for 30 seconds at room temperature to obtain a pseudo molded body. Again, it was placed in a molding mold having a diameter of 140 mm and compression molded for 2 minutes under the condition of 30 MPa. The wood molded product thus obtained was glossy without blur on the surface due to the generation of gas. The absorption rate of deposition for 24 hours was also 1% or less, and there was no odor by organic acids.

(Example 2) A sawdust of a hinoki lumber was prepared as a wood-based material used as a raw material for a molded article, and this wood-based material was adjusted to a water content of 12%. After steaming at 215 ° C. for 6 minutes, the mold was filled into a molding die having a diameter of 140 mm, and compression molded at room temperature under a pressure of 30 MPa for 3 minutes to prepare a molded product.

This pseudo-molded product was again placed in a molding die having a diameter of 140 mm and compression molded for 2 minutes under conditions of 200 占 폚 and 30 MPa. Also in this case, a molded article having low water absorption and very low generation of organic acid was obtained.

(Comparative Example 1) In Comparative Example 1, water was added to the wood-based material in place of the water content adjustment step P2 before the increase in steam shown in FIG. 1 to increase the water content to 100%. The wood-based material was steamed at 200 ° C. for 20 minutes, and then the inside of the mold was filled into a molding die having a diameter of 140 mm, and compression molded for 3 minutes under conditions of 180 ° C. and 30 MPa.

[Experimental Example 1] In order to verify the effect of the present invention, the odor of wood moldings obtained in Examples 1 and 2 and Comparative Example 1 was measured. Specifically, the amount of dissipation of the organic acid having an odor was measured. Table 1 shows the disperse amount µg / L of acetic acid and formic acid from each of the wood moldings prepared in Examples 1 and 2 and Comparative Example 1.

   Acetic acid (㎍ / ℓ)  Formic acid (㎍ / ℓ) Example 1      〈0.5      0.6 Example 2      〈0.5      0.8 Comparative Example 1        9.2      10.2

As can be seen from the results shown in Table 1, according to Examples 1 and 2 where molding was performed by adjusting the water content of the wood-based material before steaming to 8% and 12%, respectively, the wood-molded body with less odor because of less organic acid expression. Could get On the other hand, in the comparative example which did not dry before steaming, a large amount of acetic acid and formic acid which cause an odor generate | occur | produce. In addition, according to Examples 1 and 2, it was possible to obtain a wooden molded product having a smooth surface and a gloss.

As a sensory test, the results of the odor test of 10 persons of different sex and age also showed that in Example 1 and 2, all 10 patients had no unpleasant odor.

Example 3 First, a hardwood baseball bat sawdust (a mixed material of maple and Aodamo) was prepared as a wood-based material used as a raw material for a molded article, and the wood-based material was dried to adjust its water content. Process (P2)]

Thereafter, the wood-based material was subjected to a steaming treatment (P3) by compression molding for 2 minutes at a heating temperature of 180 ° C. and in the presence of 30 MPa to prepare a wood molding.

In Example 3, in the case of the increase before water content adjustment step P2, the wood molded body formed by adjusting the water content of the wood-based material to 3% using a dryer is referred to as sample S3-1. In addition, the wood molded object which adjusted the moisture content of the wood-based material to 15% using the air dryer in the pre-power-up water content adjustment process (P2) is called sample S3-2.

(Comparative Example 2) In Comparative Example 2, the water content was increased by adding water to the wood-based material in place of the increase in water content adjustment step (P2). Other processes are the same as in Example 3. A sample obtained by adding 130% by weight of water to a wood-based material is referred to as Comparative Sample H2-1, and a sample obtained by adding 200% by weight of water to a wood-based material is referred to as H2-2.

[Experiment 2]

For each of the samples obtained in Example 3 and Comparative Example 2, the results of the absorption test based on the JIS K7209A method under the conditions of 23 ° C are shown in Fig. 3 (a). According to Fig. 3 (a), Samples S3-1 and S3-2 of Example 3, in which the water content before cooking was lowered to 15% or less, were compared with Comparative Samples H2-1 and H2-2 of Comparative Example 2, in which water was added before cooking. Absorption rate is falling compared with. In addition, when comparing the experimental results of Samples S3-1 and S3-2 of Example 3, it was found that the sample S3-1, which lowered the moisture content of the wood-based material before steaming up to 3%, further lowered the water absorption and the effect was remarkable.

(Example 4, Comparative Example 3) In Example 3 and Comparative Example 2, the molded wooden body was molded at 180 ° C. In Example 4 and Comparative Example 3, the molding temperature was 210 ° C. That is, in Example 4, only the molding temperature is different from that in Example 3, and other conditions are the same as in Example 3. Similarly, in Comparative Example 3, only the molding temperature is different from Comparative Example 2, and the other conditions are the same as in Comparative Example 2.

In Example 4, before the increase in water content adjustment step (P2), the wood molded body obtained by adjusting the water content of the wood-based material to 3% using a dryer is referred to as sample S4-1. In addition, the wood molding obtained by adjusting the water content of the wood-based material to 15% by using an air dryer in the steam increase moisture content adjusting step (P2) is referred to as sample S4-2.

In Comparative Example 3, the sample obtained by adding 130% by weight of water to the wood-based material was referred to as Comparative Sample H2-1, and the sample obtained by adding 200% by weight of water to the wood-based material was referred to as Comparative Sample H2-2. It is called.

[Experiment 3]

Next, experiments performed by the present inventors on the relationship between the water content of the wood-based material and the water content of the wood molded body will be described. As in Experiment 2, Experiment 3 was subjected to a water immersion absorption test for 24 hours by JIS K7209A under the conditions of 23 ° C. The results of Experiment 3 are shown in Figure 3 (b). As shown in Fig. 3 (b), the respective samples S4 of the experiment 3 having a molding temperature of 210 ° C. compared to the samples S3-1 and S3-2 of the experiment 2 having a molding temperature of 180 ° C. (see Fig. 3 (a)). It can be seen that the absorption of -1 and S4-2 is falling. Therefore, it was found that the higher the molding temperature can lower the water absorption.

Example 5 The wood powder of yellow poplar was steamed for 20 minutes at a steam pressure of 1.8 MPa and a steam temperature of 220 ° C., and then pressed under a heat press condition of a pressure of 25 MPa, a mold cooling temperature of 80 ° C. and a heating time of 3 minutes. To form 12 test pieces of wood moldings. Each test piece is distinguished by calling it a test piece No. i (i is an integer from 1 to 12). Test piece no. 1-4 were shape | molded at the shaping | molding temperature of 170 degreeC. Test piece no. 5-8 were shape | molded at the shaping | molding temperature of 190 degreeC. In addition, test piece No. 9 to 12 were molded at a molding temperature of 210 ° C.

In addition, the moisture content before shaping | molding of each test piece was made different.

[Experiment 4]

Subsequently, experiments were conducted using the test pieces Nos. 1 to 12 obtained in Example 5 to examine the relationship between the moisture content of the wood-based material before molding and the molding temperature and the water absorptivity of the wood tongue. In Experiment 5, a water immersion absorption test was conducted for 24 hours in accordance with JIS K7209A method under the conditions of 23 ° C as in Experiment 2.

Figure 4 is a graph showing the test results of Experiment 5. As can be seen from Figs. 4 (a) to 4 (c), there is a clear correlation between the water absorption rate and the absorption thickness expansion rate of the wood moldings, and the water content before molding and the water absorption rate of the wood moldings, and the molding There is no clear correlation between the total moisture content and the absorption thickness expansion rate. On the other hand, it can be seen from the experimental results shown in FIG. 3 and the experimental results shown in FIG. 4 that it is more important to adjust the moisture content before the increase treatment than to increase the moisture content before molding.

In addition, Figure 4 (a) shows the test results of the test piece group molded at a molding temperature of 170 ℃, Figure 4 (b) shows the test results of a test piece group molded at a molding temperature of 190 ℃, Figure 4 (c) shows the test results of a group of specimens molded at a molding temperature of 210 ° C. It can be seen from these that the higher the molding temperature, the lower the absorption rate and the lower the absorption thickness expansion rate.

Claims (11)

In the method for producing wood moldings, A steam increase adjustment step of drying the wood-based material to adjust its water content; A process for increasing the content of the wood-based material whose water content is adjusted by the increase before the increase; And a molding step of molding the wood-based material which has been increased by the steaming step. The method according to claim 1, wherein the process of increasing and increasing the water content of the wood-based material is adjusted to 20% or less. The method of claim 1 or 2, wherein the molding step, A caustic molding process for temporarily forming a wood-based material which has been steamed by the steaming process; Including the main molding process for compression molding the molded article molded by the temporary molding process, And a pre-molding drying step of drying the wood-based material and adjusting its water content after at least one of the caustic molding process and the main molding process after the increase of the steaming process. . 4. The drying method according to claim 3, wherein the pre-molding drying step is carried out before the grinding step of pulverizing the wood-based material prior to the caustic molding step, to dry the water content of the wood-based material to 15% or less, In the case of carrying out before the said main shaping | molding process, the pseudo-molded object comprised from the said wood-based material is dried to 2% or less of moisture content, The manufacturing method of the wood-molded object characterized by the above-mentioned. 5. The method for producing a wood-based molded body according to claim 3 or 4, wherein the provisional molding step forms a pseudo-molded product by laminating the wood-based material in a mold to press-molding to 1 MPa or more and 20 MPa or less. The molding material according to claim 1, wherein the thermoplastic resin is added to the wood-based material which has been steamed by the steaming process so that the thermoplastic resin is contained at a ratio of 5 parts by weight to 35 parts by weight with respect to 100 parts by weight of the molding material. Resin addition process to obtain, The molding process, A method for producing a wood molded body, characterized by injection molding a molding material obtained by the resin addition step into a mold. The method of any one of claims 1 to 6, wherein the capital increase step, The wood-based material is introduced from the upper opening of the container having a ventilated side surface, and the wood-based material introduced into the container is subjected to a steam treatment. An elongated transverse member arranged between sides in the container has a cross-section orthogonal to its longitudinal direction protruding from the opening above the container, and having an open shape toward the bottom of the container. In the installed state, the wood-based material manufacturing method, characterized in that the wood material is introduced into the container. In the method for producing a wood-based material which brings the wood-based material into thermal fluidity by contacting the wood-based material with water vapor, the wood-based material for molding is formed by steam molding, caustic molding, and main molding of the wood-based material. A method for producing a wood molded body, characterized in that the moisture content is adjusted before the steam treatment and before the molding of the main molding or the main molding. The method of claim 8, wherein the moisture content of the wood-based material is adjusted to 3% or more and 20% or less and contacted with water vapor, and then the water content of the wood-based material is dried to 5% or more and 15% or less to prepare a pseudo-molded product. The compression molding was carried out after drying the obtained pseudo-molded product to 2% or less of water content. 10. The wood molded body according to claim 8 or 9, wherein the water content of the wood-based material is adjusted to 5% or more and 15% or less to fill the mold, and press molded at 1 MPa or more and 20 MPa or less to form a pseudo-molded product. Manufacturing method. In a wood molding produced by contacting wood-based material with water vapor to impart thermal fluidity to the wood-based material, Molded by steam treatment, pseudo-molding and main molding of wood-based materials, molded by adjusting the moisture content of free water and bonding water of molding wood-based materials before molding or molding .