JP2006125124A - Pavement formed of wood chips - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wood-chip pavement 1 which is environmentally friendly, good in operability, and excellent in durability. <P>SOLUTION: The pavement 1 is formed of wood chips 3 and a binder 4. The wood chips 3 adjacent to each other are connected together by the binder 4. The binder 4 is made of a resin composition which contains a biodegradable resin as a base polymer. The resin composition contains an antimicrobial agent of plant origin. Preferably the mixing ratio of the antimicrobial agent of plant origin with respect to the biodegradable resin of 100 pts.mass is set to 1 pt.mass or more, more preferably to 3 pts.mass or more, and further preferably to 5 pts.mass or more. Preferably the antimicrobial agent is wood vinegar. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to pavement using wood chips.

  Wood chip pavement is used for sidewalks in the park. In this pavement, a large number of wood chips are spread on the ground. Wood chip pavement is becoming widespread for reasons such as providing appropriate elasticity, obtaining a natural texture, and being friendly to the natural environment.

  Wood chips are exposed on the surface of the pavement. The surface of this pavement has irregularities. When a wheelchair passes over a wood chip pavement, the wheelchair is subject to significant vibrations due to the unevenness. The vibration is uncomfortable for wheelchair users. Wheelchair wheels may sink into the pavement and hinder traffic.

  If this pavement is exposed to strong winds during a typhoon, wood chips may be scattered. In addition, wood chips may be scattered by children and pets running around on the pavement.

  A pavement in which wood chips are bonded with a synthetic resin binder has been proposed. In this pavement, the space between the wood chips is filled with a synthetic resin binder, so that the surface is relatively smooth. In addition, since the wood chip is hardened with a synthetic resin binder, it is difficult for the wheels to sink. This pavement is also an enemy to wheelchair traffic. Since the wood chips are bonded with a binder, the wood chips are hardly scattered.

  Since wood chips are broken down into microorganisms, the wood chip pavement gradually deteriorates. The old pavement is removed and a new wood chip pavement is constructed. When the removed pavement is discarded, the synthetic resin binder continues to remain in the natural environment. Synthetic resin binders destroy the natural environment. When the removed pavement is incinerated, a large amount of carbon dioxide is generated by the combustion of the synthetic resin binder. Carbon dioxide causes global warming.

Japanese Unexamined Patent Application Publication No. 2003-34904 discloses a wood chip pavement using a biodegradable resin as a binder. Even when the pavement is discarded, both the wood chips and the binder are microbially degraded. This pavement is friendly to the natural environment.
JP 2003-34904 A

  In wood chip pavement in which a biodegradable resin is used as the binder, the binder tends to be microbially decomposed earlier than the wood chip is microbially decomposed. In other words, this pavement is inferior in durability. After the binder is microbially decomposed, it is difficult to pass by a wheelchair, and the wood chips are easily scattered. This pavement must be rebuilt frequently, increasing the park manager's cost burden.

  An object of the present invention is to provide a wood chip pavement that is friendly to the natural environment, easy to use, and excellent in durability.

  The pavement according to the present invention includes a large number of wood chips and a binder for bonding these wood chips. This binder contains a biodegradable resin and a plant-derived antibacterial agent.

  Preferably, wood vinegar is used as a plant-derived antibacterial agent. Preferably, the blending amount of the plant-derived antibacterial agent is 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the biodegradable resin.

  In this pavement, antimicrobial agents delay the microbial degradation of the binder. This pavement is excellent in durability. Even when the pavement is discarded, both the wood chips and the binder are microbially degraded. This pavement is friendly to the natural environment.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  FIG. 1 is a cross-sectional view showing a pavement 1 according to an embodiment of the present invention together with a foundation 2. The thickness of the pavement 1 is usually 2 cm or more and 15 cm or less. The pavement 1 includes a wood chip 3 and a binder 4. Adjacent wood chips 3 are joined together by a binder 4.

  The wood chip 3 is obtained by converting wood into chips. If thinned wood and waste wood are used as wood, resource saving is achieved. The size of the wood chip 3 is usually 2 cm or more and 10 cm or less. Examples of the material of the wood chip 3 include cedar, firewood, and pine.

  The binder 4 is made of a resin composition. The base polymer of this resin composition is a biodegradable resin. Biodegradable resins are resins that can be degraded by microorganisms in nature. Specific examples of the biodegradable resin include cellulose acetate resin, starch resin (for example, chitosan-cellulose-starch polymer), aliphatic polyester resin, and the like.

  The resin composition contains a plant-derived antibacterial agent. Specific examples of this antibacterial agent include wood vinegar, bamboo vinegar, strawberry thiol, wasabi extract, garlic extract, mustard extract, chili powder and the like. From the viewpoint of easy availability and excellent workability during kneading with the base polymer, wood vinegar is preferred. Wood vinegar is obtained by dry distillation of wood. Wood vinegar contains wood spirit (methyl alcohol), acetone and tar-like substances.

  By blending a plant-derived antibacterial agent, the durability of the pavement 1 is improved, as will be described in detail later. From the viewpoint of durability, the blending amount of the plant-derived antibacterial agent is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and particularly preferably 5 parts by mass or more with respect to 100 parts by mass of the biodegradable resin. From the viewpoint of cost and workability, the blending amount of the plant-derived antibacterial agent is preferably 30 parts by mass or less with respect to 100 parts by mass of the biodegradable resin.

  In order to construct the pavement 1, first, a biodegradable resin emulsion and wood vinegar are mixed. Next, this composition and the wood chip 3 are kneaded. Next, the kneaded material is laid on the base 2 and leveled. Then, moisture is vaporized and the resin composition is cured. This resin composition forms the binder 4 and the pavement 1 is completed. The volume ratio between the biodegradable resin and the wood chip 3 is preferably 5/95 or more and 60/40 or less, more preferably 10/90 or more and 40/60 or less in terms of solid content. Only the wood chip 3 may be laid on the base 2, and the emulsion may be flowed from above. Instead of the emulsion, a resin composition whose viscosity is lowered by mixing with a solvent may be used.

  Since the pavement 1 includes the binder 4, the surface unevenness is small. Even if a wheelchair or bicycle passes through this pavement 1, there is little vibration. In addition, since the wood chips 3 are bonded to each other with the binder 4, the wheels are unlikely to sink.

  In this pavement 1, since the wood chips 3 are coupled to each other, the wood chips 3 are not easily scattered by strong winds or the like.

  Even if the pavement 1 is removed from the ground 2 and discarded, both the wood chip 3 and the binder 4 can be decomposed by microorganisms. This binder 4 does not remain in nature. This pavement 1 is friendly to the natural environment. Since both the wood chip 3 and the binder 4 are decomposed, the pavement 1 can be used as compost.

  Since the antibacterial agent is blended in the pavement 1, the decomposition of the binder 4 by microorganisms is suppressed. In this pavement 1, decomposition proceeds gradually. This pavement 1 is also excellent in durability.

  Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be construed in a limited manner based on the description of the examples.

[Example]
100 parts by mass of an aliphatic polyester biodegradable resin emulsion in terms of solid content and 10 parts by mass of wood vinegar were kneaded to obtain a resin composition. This resin composition and wood chips were kneaded so that the volume ratio of biodegradable resin and wood chips was 35/65, and laid on a wooden frame. Thus, a square test piece having a side of 30 cm was obtained.

[Comparative example]
A test piece was obtained in the same manner as in the example except that wood vinegar was not blended.

  The test piece of an Example and a comparative example was left outdoors and watered every day. When the state of the test piece after 4 months was visually confirmed, the binder of the comparative example was aged more than the binder of the example. From this evaluation result, the superiority of the present invention is clear.

  The pavement according to the present invention can be used for various applications such as parks, promenades, and exhibition halls.

FIG. 1 is a cross-sectional view showing a pavement according to an embodiment of the present invention together with a base.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Paving 2 ... Base 3 ... Wood chip 4 ... Binder

Claims (3)

  A pavement comprising a large number of wood chips and a binder for binding these wood chips, the binder comprising a resin composition containing a biodegradable resin and a plant-derived antibacterial agent.   The pavement according to claim 1, wherein the plant-derived antibacterial agent is wood vinegar.   The pavement according to claim 1 or 2, wherein the amount of the plant-derived antibacterial agent is 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the biodegradable resin.

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