WO2016056207A1

WO2016056207A1 - Plant-based board production method and plant-based board

Info

Publication number: WO2016056207A1
Application number: PCT/JP2015/004997
Authority: WO
Inventors: 菅原　亮
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2014-10-08
Filing date: 2015-10-01
Publication date: 2016-04-14

Abstract

Provided is a plant-based board production method in which an adhesive and a plurality of plant pieces having a lignin content of 15-20 wt% and a density of 0.15-0.20 g/cm³ are subjected to hot press molding and the curing of the adhesive causes the plurality of plant pieces to adhere to one another.

Description

Method for producing plant-based board and plant-based board

The present disclosure relates to a method for producing a plant board and a plant board.

A method of manufacturing a fiberboard by hot-pressing long kenaf fibers dispersed in an adhesive is known (Patent Document 1).

JP 2000-263519 A

Method for producing a plant board of the present disclosure, the content of lignin is 15 wt% or more, 20 wt% or less, and density of 0.15 g / cm ³ or more, a plurality of plant pieces is 0.20 g / cm ³ or less, The adhesive applied to each of the plurality of plant pieces is hot-press molded, and each of the plurality of plant pieces is bonded to each other by curing of the adhesive.

With the above configuration, it is possible to manufacture a plant-based board that is superior in bending strength and water absorption thickness expansion rate compared to the conventional one.

FIG. 1 is a partial cross-sectional view of a plant board before hot pressing according to an embodiment. FIG. 2 is a partial cross-sectional view of the plant board after hot pressing according to the embodiment. Drawing 3 is a figure explaining orientation of a plurality of plant pieces in each layer of a plurality of layers of plant boards concerning an embodiment.

Prior to the description of the embodiment of the present disclosure, a related art plant board manufacturing method will be described.

For example, in the method for producing a plant-based board disclosed in Japanese Patent Application Laid-Open No. 2000-263519, a plant-based board is formed by hot-pressing long kenaf fibers dispersed in an adhesive. Therefore, it has been difficult to uniformly disperse the long fiber kenaf and cure the adhesive. If the distribution of kenaf in the plant board becomes non-uniform, it will cause a decrease in bending strength. In addition, it has been difficult to lower the rate of expansion of the absorption thickness of plant-based boards containing long fiber kenaf.

Among the constituent elements in the embodiment, constituent elements that are not described in the independent claims indicating the highest concept of the present disclosure are described as arbitrary constituent elements. Accordingly, numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, and the like shown in the following embodiments are merely examples, and do not limit the present disclosure.

Each figure is a schematic diagram and is not necessarily shown strictly. In each figure, substantially the same structure is denoted by the same reference numeral, and redundant description is omitted or simplified.

(Embodiment)
Hereinafter, a method for manufacturing a plant board according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 3. FIG. 1 is a cross-sectional view of a plant board before hot pressing according to this embodiment. FIG. 2 is a cross-sectional view of the plant board after hot pressing according to the present embodiment. FIG. 3 is a diagram for explaining the orientation of a plurality of plant pieces in each layer of a plurality of plant-based boards according to this embodiment.

The plant-based board 10 according to this embodiment includes a plurality of plant pieces 1 having a lignin content of 15 wt% or more and 20 wt% or less and a density of 0.15 g / cm ³ or more and 0.20 g / cm ³ or less. It is formed by hot-pressing the adhesive 2 attached to each of the plurality of plant pieces 1. Each of the plurality of plant pieces 1 is bonded by curing the adhesive 2. The plant piece 1 has an elongated flake shape, and is obtained by cutting and pulverizing a plant with a flaker, a hammer mill, a ring breaker, or the like. As the plant, any part such as a stem, a bark, a seed, or a leaf of a herbaceous plant or a woody plant can be used, and one kind may be used, or two or more kinds may be used at the same time. .

Moreover, the plant used for the plant piece 1 can be used in various states such as unused ones, wastes, and recycled materials.

In this embodiment, the plant piece 1 having a lignin content of 20 wt% or less and a density of 0.20 g / cm ³ or less obtained by pulverizing and cutting the stem core of a herbaceous plant is used. The lower limit of the preferred lignin content is 15 wt%. The lower limit of the preferred density is 0.15 g / cm ³ . Herbaceous plants include kenaf, jute such as Kuma and Shimatsunaso. The stem core part of the herbaceous plant can be obtained by removing the bast fibers existing in the outer peripheral part such as kenaf and jute.

Adhesives 2 include thermosetting resins such as urea resins, melamine resins, phenol resins, resorcinol resins, epoxy resins, urethane resins, furfural resins, isocyanate resins, and sugars such as sucrose. And a heat-curing binder obtained by reacting a polyvalent carboxylic acid such as citric acid with an acid such as p-toluenesulfonic acid.

Hereinafter, a method for forming a plant board according to this embodiment will be described.

First, the adhesive 2 is attached to the plant piece 1. Examples of the deposition method include the following methods. A method of spraying the liquid adhesive 2 while rotating the plant piece 1 in the drum using an apparatus such as a drum blender. A method of immersing the plant piece 1 in a tank filled with the liquid adhesive 2. The method of mixing the plant piece 1 and the powdery adhesive 2 using apparatuses, such as a mixer. The amount of the adhesive 2 is not particularly limited as long as the plurality of plant pieces 1 are bonded to each other with sufficient strength. In this embodiment, 10 to 15 wt% of the adhesive is used with respect to the total weight of the plant piece 1.

The plant piece 1 to which the adhesive 2 is applied is placed in a plate shape as shown in FIG. 1 and then hot-press molded, and the plant pieces 1 are bonded to each other so that the plant-based board is formed as shown in FIG. can get.

The plant piece 1 preferably has an elongated shape with a length of 50 mm or more. Thereby, compared with the case where the plant piece 1 less than 50 mm in length is used, the plant-type board 10 of high bending strength is obtained. There is no particular upper limit on the length of the plant piece 1, but considering the productivity, the length of the plant piece 1 is preferably 200 mm or less. Considering that part of the plant piece 1 is crushed in the production process, the majority of the plant pieces 1 included in the plant board 10 are preferably 50 mm in length and 200 mm or less in length.

The plant pieces 1 to which the adhesive 2 is applied may be arranged randomly or may be arranged with the plant pieces 1 oriented in an arbitrary direction. Moreover, the plant piece 1 to which the adhesive 2 is adhered may be arranged in a single plate shape, or may be arranged so as to laminate a plurality of layers. When laminating a plurality of layers, each layer may be composed of the same or different plant pieces 1. Moreover, when laminating | stacking a some layer, each layer may be comprised by the orientation of the plant piece 1 which is the same or different.

A method for producing the plant board 20 having a plurality of layers will be described with reference to FIG. The plant-based board 20 has a first surface layer 20A1, a core layer 20B, a second surface layer 20A2, and an adhesive (not shown) for fixing them. FIG. 3 is a perspective view showing a state in which each layer is developed in a direction perpendicular to the plane direction (XY plane) (Z axis) in order to explain the configuration of the plant-based board 20.

The plant-based board 20 having a plurality of layers includes a first plurality of plant pieces 11 constituting the first surface layer 20A1, a second plurality of plant pieces 12 constituting the second surface layer 20A2, and a first surface layer. A plurality of plant pieces that are provided between 20A1 and the second surface layer 20A2 and are composed of a plurality of third plant pieces 13 constituting the core layer 20B, and an adhesive (not shown) are hot-press molded. Is formed. The first plurality of plant pieces 11, the third plurality of plant pieces 13, and the second plurality of plant pieces 12 overlap in this order, and are bonded by curing the adhesive.

It is preferable that the plant pieces constituting each layer have the same orientation. The orientation indicates the longest length direction of the elongated plant piece. The first plurality of plant pieces 11 are aligned in the first orientation D1, the second plurality of plant pieces 12 are aligned in the second orientation D2, and the third plurality of plant pieces 13 are It is aligned with the third orientation D3.

Furthermore, the first orientation D1 and the second orientation D2 are preferably orthogonal to the third orientation D3. In FIG. 3, the first orientation D1 and the second orientation D2 are oriented in the Y-axis direction. The third orientation D3 is oriented in the X-axis direction. With this configuration, the bending strength of the plant board 20 is higher than when the plant pieces are oriented in the same direction or randomly.

Hot pressing is performed by batch type flat plate press or continuous press. The pressing temperature, pressing time, pressing pressure, and the like are appropriately set according to the type of the adhesive 2 to be used and the thickness of the plant board to be molded.

It is preferable to smooth the surface opposite to the core layer 20B of the first surface layer 20A1 and the surface opposite to the core layer 20B of the second surface layer 20A2. Thereby, compared with the case where a surface layer has an unevenness | corrugation, the crack of a plant-type board etc. becomes difficult to produce.

Examples and comparative examples according to the present embodiment are shown below.

(Example 1)
In this example, a crushed stalk core obtained by pulverizing a stalk core with a hammer mill was used as the plant piece 1. The lignin content of the june stalk core was 15 wt%, and the density of the june stalk core was 0.17 g / cm ³ . The content of lignin can be quantified by, for example, the Van Soest method. As the adhesive 2, a urea melamine resin adhesive (for example, TB103 manufactured by Oshika) was used. The average particle size of the ground stalk core used in this example was 2.2 mm. For example, the average particle diameter can be determined by a screening test based on JISZ8815.

Hereinafter, a method for forming a plant-based board in this example will be described.

First, using a drum blender (for example, PT60 manufactured by Magellar), a urea melamine resin-based adhesive was spray-applied to the crushed stalk core and adhered. The weight of the urea melamine resin-based adhesive was 15 wt% with respect to the weight of the crushed stalk core. Next, crushed stalk cores coated with a urea melamine resin adhesive were randomly arranged in a single-layer plate shape. Then, using a hot-pressure molding machine (for example, SF60 manufactured by Shinfuji Metal Industry), the plant board was molded by hot pressing at a press temperature of 150 ° C., a press pressure of 25 × 10 ⁵ Pa, and a press time of 10 minutes.

(Example 2)
In the present example, as the plant piece 1, a pulverized pine shoot stem core obtained by pulverizing a pine shoot stem core with a ring flaker was used. The content of lignin in the pine stem stem core was 14 wt%, and the density of the pine stem stem core was 0.16 g / cm ³ . As the adhesive 2, 10 parts by mass of sucrose (for example, manufactured by Wako Pure Chemical), 4 parts by mass of citric acid (for example, manufactured by Wako Pure Chemical) and p-toluenesulfonic acid (for example, manufactured by Wako Pure Chemical) 2 A saccharic acid-based adhesive mixed with parts by mass and further dissolved in water was used. The pulverized pine needle stem core used in this example had an average length of 8 mm, an average width of 2 mm, and an average thickness of 1 mm.

First, a sugar-based adhesive was spray-applied to and adhered to a ground pine stalk core using a drum blender. The weight of the saccharide-based adhesive was 15 wt% with respect to the weight of the ground stalks of Shimashimaso stem. Next, the pulverized Shimano stalk core coated with a saccharide adhesive was randomly arranged in a single-layer plate shape. Then, using a hot press molding machine, the plant board was molded by hot pressing at a press temperature of 200 ° C., a press pressure of 25 × 10 ⁵ Pa, and a press time of 10 minutes.

(Example 3)
In this example, a kenaf stalk core strand obtained by pulverizing a kenaf stalk core with a flaker was used as the plant piece 1. The lignin content of the kefna stalk core was 19 wt%, and the density of the kefna stalk core was 0.15 g / cm ³ . As the adhesive 2, a phenol resin adhesive (for example, B1360 manufactured by Oshika) was used. The kenaf stalk core strand used in this example had an average length of 55 mm, an average width of 12 mm, and an average thickness of 0.6 mm.

First, a phenol resin adhesive was spray-coated on the kenaf stalk core strand by a drum blender and attached. The weight of the phenol resin adhesive was 15 wt% with respect to the weight of the kenaf stalk core strand. Next, the first surface layer, the core layer, and the second surface layer were laminated in the following order. As a first surface layer, a kenaf stalk core strand coated with a phenol resin adhesive was oriented in one direction. The core layer was arranged on the first surface layer so as to be oriented in a direction orthogonal to the orientation of the first surface layer. Further, the second surface layer was arranged on the core layer so as to be oriented in a direction orthogonal to the orientation of the core layer. Then, using a hot pressure molding machine (SF60 manufactured by Shindo Metal Industry), the plant board was molded by hot pressing at a press temperature of 200 ° C., a press pressure of 25 × 10 ⁵ Pa, and a press time of 10 minutes.

Example 4
In the present Example, as the plant piece 1, a jum stalk core strand obtained by cutting a jum stalk core in the length direction was used. The lignin content of the june stalk core was 15 wt%, and the density of the june stalk core was 0.17 g / cm ³ . As the adhesive 2, an isocyanate resin adhesive (for example, a wood cure manufactured by Nippon Polyurethane Industry) was used. The juvenile stem core strand used in this example had an average length of 200 mm, an average width of 12 mm, and an average thickness of 12 mm.

First, with a drum blender, an isocyanate resin-based adhesive was spray-coated on the stalk core strand, and was attached. The weight of the isocyanate resin-based adhesive was 10 wt% with respect to the weight of the stalk core strand. Next, the first surface layer, the core layer, and the second surface layer were laminated in the following order. As the first surface layer, a juvenile stem core strand coated with an isocyanate resin adhesive was oriented in one direction. The core layer was arranged on the first surface layer so as to be oriented in a direction orthogonal to the orientation of the first surface layer. Further, the second surface layer was arranged on the core layer so as to be oriented in a direction orthogonal to the orientation of the core layer. Then, using a hot pressure molding machine (SF60 manufactured by Shindo Metal Industry), the plant board was molded by hot pressing at a press temperature of 200 ° C., a press pressure of 25 × 10 ⁵ Pa, and a press time of 10 minutes.

(Comparative Example 1)
In this comparative example, a crushed softwood material obtained by pulverizing with a hammer mill was used as the plant piece 1. The lignin content in the crushed softwood material was 28 wt%, and the density of the crushed softwood material was 0.46 g / cm ³ . The average particle diameter of the crushed softwood material used in this comparative example was 2.2 mm.

Other conditions were the same as in Example 1, and a plant-based board was molded.

(Comparative Example 2)
In this comparative example, a pulverized balsa material obtained by pulverization with a ring flaker was used. The content of lignin in the balsa material was 24 wt%, and the density of the balsa material was 0.19 g / cm ³ . The pulverized balsa material had an average length of 8 mm, an average width of 2 mm, and an average thickness of 1 mm.

Other conditions were the same as in Example 2, and a plant-based board was molded.

(Comparative Example 3)
In this comparative example, the balsa material strand obtained by grind | pulverizing a balsa material with a flaker as the plant piece 1 was used. The content of lignin in the balsa material was 24 wt%, and the density of the balsa material was 0.19 g / cm ³ . The balsa material strands had an average length of 8 mm, an average width of 2 mm, and an average thickness of 1 mm.

Other conditions were the same as in Example 3, and a plant board was molded.

(Comparative Example 4)
In this comparative example, a crushed stalk core obtained by pulverizing a stalk core with a hammer mill was used as the plant piece 1. The lignin content of the june stalk core was 25 wt%, and the density of the june stalk core was 0.19 g / cm ³ . The average particle size of the crushed stalk core used in this comparative example was 2.2 mm.

(Comparative Example 5)
In this comparative example, as a plant piece 1, a pulverized pine shoot stem core obtained by pulverizing a pine shoot stem core with a ring flaker was used. The content of lignin in the stem core of the Japanese pine was 22 wt%, and the density was 0.18 g / cm ³ . The ground pine stalk core used in this comparative example had an average length of 8 mm, an average width of 2 mm, and an average thickness of 1 mm.

(Comparative Example 6)
In this comparative example, a kenaf stalk core strand obtained by cutting a kenaf stalk core in the length direction was used as the plant piece 1. The lignin content of the kefna stalk core was 23 wt%, and the density of the kefna stalk core was 0.15 g / cm ³ . As the adhesive 2, an isocyanate resin adhesive (for example, a wood cure manufactured by Nippon Polyurethane Industry) was used. The kenaf stalk core strand used in this example had an average length of 200 mm, an average width of 12 mm, and an average thickness of 12 mm.

Other conditions were the same as in Example 4, and a plant-based board was molded.

(Comparative Example 7)
In this comparative example, a jute bast fiber strand obtained by cutting jute bast fibers in the length direction was used as the plant piece 1. The content of lignin in the jute bast fiber was 11 wt%, and the density of the jute bast fiber was 0.49 g / cm ³ . As the adhesive 2, a phenol resin adhesive (for example, B1360 manufactured by Oshika) was used. The jute bast fiber strand used in this example had an average length of 200 mm, an average width of 0.1 mm, and an average thickness of 0.1 mm. The press temperature during hot pressing was 150 ° C.

(Evaluation)
The results of bending strength test and water absorption thickness expansion test according to JIS A5908 are shown below for each of the plant-based boards of Examples 1 to 4 and Comparative Examples 1 to 7. The bending strength test preferably has a high strength, and the water absorption thickness expansion coefficient test preferably has a low expansion coefficient.

In plant piece 1, the evaluation results are shown in Table 1 for the plant boards of Example 1, Comparative Example 1 and Comparative Example 4 in which the average particle size is 2.2 mm, the orientation of the plant pieces is random, and the layer structure is a single layer Show.

The plant board of Example 1 has higher bending strength and lower water absorption thickness expansion rate than the plant boards of Comparative Examples 1 and 4.

Table 2 shows the evaluation results for the plant boards of Example 2, Comparative Example 2 and Comparative Example 5 in which the length of the plant piece 1 is 8 mm, the orientation of the plant piece 1 is random, and the layer structure is a single layer.

The plant-based board of Example 2 has higher bending strength and lower water absorption thickness expansion rate than Comparative Examples 2 and 5.

Table 3 shows the evaluation results for Example 3 and Comparative Example 3 of the plant board in which the length of the plant piece 1 is 55 mm, the orientation of the plant piece 1 is orthogonal, and the layer structure is three layers.

The plant board of Example 3 has higher bending strength and lower water absorption thickness expansion rate than the plant board of Comparative Example 3.

Table 4 shows the evaluation results for Example 4, Comparative Example 6 and Comparative Example 7 of the plant board in which the length of the plant piece 1 is 200 mm, the orientation of the plant piece 1 is orthogonal, and the layer structure is three layers.

The plant board of Example 4 has higher bending strength and lower water absorption thickness expansion rate than the plant boards of Comparative Examples 6 and 7.

As shown in Tables 1 to 4, a plant board in which the lignin content of the plant piece 1 is 15 wt% or more and 20 wt% or less, and the density is 0.15 or more g / cm ³ and 0.20 g / cm ³ or less. Bending strength is high, and the water absorption thickness expansion coefficient is low.

1, 11, 12, 13 Plant piece 2

Adhesive

10, 20 Plant-based board 20A1, 20A2 Surface layer 20B Core layer D1, D2, D3 Orientation

Claims

The content of lignin 15 wt% or more, 20 wt% or less, and density of 0.15 g / cm 3 or more, a plurality of plant pieces is 0.20 g / cm 3 or less,
Hot pressing with an adhesive applied to each of the plurality of plant pieces,
A method for producing a plant-based board, wherein each of the plurality of plant pieces is bonded to each other by curing of the adhesive.
The method for producing a plant-based board according to claim 1, wherein each of the plurality of plant pieces has an elongated shape and has a length of 50 mm or more and 200 mm or less.
The plurality of plant pieces includes a first plurality of plant pieces constituting a first surface layer, a second plurality of plant pieces constituting a second surface layer, and a third plurality of plants constituting a core layer. With a piece,
The manufacturing method of the plant-type board of Claim 1 or 2 which laminates | stacks in order of said 1st some plant piece, said 3rd some plant piece, and said 2nd some plant piece.
The first plurality of plant pieces are aligned in a first orientation;
The second plurality of plant pieces are aligned in a second orientation;
The third plurality of plant pieces are aligned in a third orientation;
The first orientation and the second orientation are orthogonal to the third orientation,
The manufacturing method of the plant-type board of Claim 3.
Smoothing the surface of the first surface layer opposite to the core layer and the surface of the second surface layer opposite to the core layer;
The manufacturing method of the plant-type board of Claim 3 or 4.
The method for producing a plant board according to any one of claims 1 to 5, wherein the adhesive is 10 wt% or more and 15 wt% or less with respect to a total weight of the plurality of plant pieces.
Each of the plurality of plant pieces is a stem core of a herbaceous plant.
The method for producing a plant-based board according to any one of claims 1 to 6.
A plant board comprising a plurality of plant pieces having a lignin content of 15 wt% or more and 20 wt% or less and a hardened adhesive.
The plant-based board according to claim 8, wherein each of the plurality of plant pieces has an elongated shape and has a length of 50 mm or more and 200 mm or less.
The plurality of plant pieces includes a first plurality of plant pieces constituting a first surface layer, a second plurality of plant pieces constituting a second surface layer, and a third plurality of plants constituting a core layer. With a piece,
The plant board according to claim 8 or 9, wherein the first plurality of plant pieces, the third plurality of plant pieces, and the second plurality of plant pieces overlap in this order.
The first plurality of plant pieces are aligned in a first orientation;
The second plurality of plant pieces are aligned in a second orientation;
The third plurality of plant pieces are aligned in a third orientation;
The plant-based board according to claim 10, wherein the first orientation and the second orientation are orthogonal to the third orientation.
The plant-based board according to claim 10 or 11, wherein a surface of the first surface layer opposite to the core layer and a surface of the second surface layer opposite to the core layer are smooth surfaces.
Each of the plurality of plant pieces is a stem core of a herbaceous plant.
The plant board according to any one of claims 8 to 12.