JPH10230574A - Timber protective sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent change of quality observed in natural drying of stock in the open and to facilitate discarding disposal after use by forming a sheet of a laminate of a vent layer made at least of extrafine long fiber and a polyolefin reinforcing base material. SOLUTION: The timber protective sheet 1 is constituted by a laminate of a polyolefin reinforcing base material 11 and a vent layer 20 made of extrafine long fiber. And, in the olefin resin used for the material 11, woven fabric or unoriented sheet made of yarns or oriented tape is supplied as a constituting material of the material 11. Then, polyolefin resin of the fiber for constituting the layer 20 is constituted by executing processing in combination of a die or nozzle provided with a fine rack or single hole and nonwoven fabric manufacturing technology using binder. The sheet 1 is laminated by previously conveying the material 11 at the time of forming the layer 20 of the fiber, spraying the fiber heated and softened on a surface of the material 11, entangling it and then fixing it by thermally embossing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective sheet for raw wood, which is dried at a storage place such as a log, a raw wood, or a lumber that is distributed and supplied to a lumber processor, and further dried and distributed by the distribution. In addition to the above, the present invention belongs to a protective sheet that not only protects from external damage but also continues natural drying during the distribution process.

[0002] In the following description, in the present specification, raw wood, logs,
Logs, lumber, lumber, and lumber are defined as follows. Raw Tree: A freshly cut, yet fresh tree. A tree that never dries. Log: The material from which the bark is bare, a log. Log: A tree used as a raw material. Sawmilling: Making felled trees into square lumber and planks. Wood: Wood that is cut and used for various purposes. Timber: Wood that has been trimmed as a material for building and tool making.

[0003]

2. Description of the Related Art Conventionally, logs and wood obtained by cutting the logs are piled up in tens of units in the open air and are naturally dried for the purpose of dimensional stability and weight reduction. I was As a method of drying wood, a forced drying method such as high-frequency heating has been developed, but the cost is high due to indoor drying, and cracks occur in the case of large wood due to rapid drying. There was only natural (open pile) drying.

[0004] Natural drying by field piles is low cost, but due to exposure to the weather, discoloration and discoloration of wood,
The decrease in yield was unavoidable due to mold generation and deterioration (corrosion, deterioration, erosion) caused by wood rot fungi.

[0005] In order to prevent deterioration due to drying in the field pile, particularly erosion due to moisture (rain) and to dry, dozens of woods are spaced apart so as to be well ventilated, for example, piled up in a cross-girder shape. It was made of not only a waterproof sheet (a sheet having water repellency (water pressure resistance) through which moisture does not pass), but also a sheet having air permeability (eg, a microporous plastic sheet obtained by stretching a plastic sheet containing a large amount of inorganic substances). Drying was possible using the cover. Ordinary breathable sheets are expensive and difficult to dispose of, so that they can be collected and reused, or used at the site of use, for example.
It has also been studied to use it as a cushioning material for building wall interiors or as a heat insulating material.

However, in the case of re-use, it is difficult to construct an efficient collection route because the use sites are dispersed, and in order to protect the cube, a protection sheet sewn into various three-dimensional shapes is collected. Even so, it is difficult to wash and repair, and it has been considered to use it as a cushioning material or a heat insulating material for the interior wall of a building, but there is a problem that it is difficult to insert and install. In addition, even when incinerated and disposed of, it is difficult to move to the incineration and disposal place because it is sewn into various three-dimensional shapes and is bulky.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sheet which prevents deterioration and is easily decomposed after use, and which is easy to dispose of after being used for natural drying by conventional stacking. It is.

[0008]

SUMMARY OF THE INVENTION The present invention for solving the above-mentioned problems is to provide a method for producing timber to be used for processing of building materials and tools, by natural drying of raw wood, and after lumbering from logs, further natural drying in a distribution process. In the wood protection sheet to be produced, the sheet is a wood protection sheet comprising a laminate of at least a breathable layer made of ultrafine long fibers and a polyolefin-based reinforcing substrate. The ventilation layer and the reinforcing base made of the ultrafine fibers are a wood protective sheet mainly composed of polypropylene. Further, the present invention is a wood protective sheet in which the ventilation layer and the reinforcing base made of the above-mentioned ultrafine long fibers are made of a biodegradable plastic and / or a photodegradable plastic.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a wood protective sheet according to the present invention comprises a laminate of a polyolefin-based reinforcing base material 11 and a gas permeable layer 20 made of ultrafine fibers. It is. In another configuration, FIG.
As shown in the figure, a polyolefin-based reinforcing base material 11, a ventilation layer 20 made of ultrafine long fibers, a polyolefin-based reinforcing base material 12
And a wood protection sheet 1 composed of a laminate of the above. The ventilation layer 20 made of the ultrafine fibers and the reinforcing substrates 11 and 12 are the wood protection sheet 1 mainly composed of polypropylene. Moreover, the ventilation layer 20 and the reinforcing base materials 11 and 12 made of the above-mentioned ultrafine fibers are made of a biodegradable plastic and / or a photodegradable plastic.

[0010] The polyolefin resin-based reinforcing substrate used in the present invention may be a non-woven fabric formed from fibers of the resin.
Sheets (warifs, sofs) and the like in which the resin yarns or drawn tapes are crossed and laminated.

The polyolefin resin used for the reinforcing base material is polyethylene, polypropylene, polystyrene, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic ester copolymer, There are ionomers. Then, these yarns, woven fabric made of stretched tape, or unstretched sheet can be used as a constituent material of the reinforcing base material.

As the polyolefin resin, a composition mainly composed of polypropylene is preferably used from the viewpoint of degradability and water repellency. The sheet used on the side that comes in contact with wood as the reinforcing base material 12 uses a low rigidity ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic ester copolymer, ionomer, or the like. You can also.

The polyolefin resin of ultrafine long fibers constituting the gas permeable layer 20 is polyethylene, polypropylene, polystyrene, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic ester copolymer, ionomer. and so on. Then, these fibers are processed by a combination of a die or a nozzle provided with minute cracks or single holes and a nonwoven fabric manufacturing technique using a binder to form a gas-permeable layer of ultrafine long fibers made of a polyolefin resin.

The degradable plastic used in the present invention is:
It is a resin that degrades over time, and the degradation is performed by light and / or microorganisms.

Photodegradable plastics have a carbonyl group in polyethylene, and the rate of decomposition can be controlled by the content of the carbonyl group. Usually, it is 1 to 10 mol%. Further, the decomposition rate can be enhanced by adding a metal oxide and / or an organic metal salt. Metal oxides that can be used include iron oxide, cobalt oxide, manganese oxide, and the like. Examples of the organic metal salts include sterates such as iron stearate, cerium stearate, and cobalt stearate, naphthenates, octylates, and rosinates. The amount of the metal salt to be added is 1 to 5000 ppm as a metal per 100 parts by weight of the resin.

The biodegradable plastics are decomposed by microorganisms, and include polyesters polymerized by microorganisms or mixtures of polyethylene with polycaprolactone, starch, and polyesters polymerized by microorganisms. As the polyester polymerized by the microorganism, a random copolymerized polyester of 3-hydroxybutyrate and 3-hydroxyvalerate (for example, propionic acid is supplied to hydrogen bacteria produced by ICI, UK) And a polyester mainly composed of 3-hydroxybutyrate obtained by supplying valeric acid to hydrogen bacteria.

The above polyethylene used for the biodegradable plastic has a density of 0.900 to 0.950 g / c.
m ³ , melt flow rate (MFR) 0.4 to 40 g
Ethylene homopolymer, or a random or block copolymer of ethylene with other olefins such as propylene, hexene, octene, 3-methylpentene-1, and ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer There is a copolymer with a monomer having an ethylenically unsaturated group such as a polymer, an ethylene / acrylate copolymer, and maleic anhydride.

The polycaprolactone used for the biodegradable plastic has a weight average molecular weight of about 4000 obtained by ring-opening polymerization of ε-caprolactone.
The above-mentioned starch is a polymer of D-glucose and is produced from roots, stems, and seeds of potato, corn, wheat and the like. And, the weight average molecular weight varies greatly from 10 ⁴ to 10 ^7, and the average particle size of such starch is preferably 10 μm or less.

A mixture of polycaprolactone, starch and a polyester polymerized by a microorganism contained in a biodegradable plastic comprising a mixture of polyethylene, caprolactone, starch and a polyester polymerized by a microorganism is based on 100 parts by weight of polyethylene. ,
5 to 400 parts by weight are preferred. When the mixing ratio of the above-mentioned biodegradable plastic is 5 parts by weight or less, the microbial degradability is insufficient, while when it exceeds 400 parts by weight, the strength is reduced and the practicality is lacking.

By using the above-mentioned photodegradable polyethylene as a raw material of the biodegradable plastic, a degradable plastic having both photodegradability and biodegradability can be obtained.

Among the above-mentioned various degradable plastics, preferred are a photodegradable plastic containing a carbonyl group and a biodegradable plastic polymerized by a microorganism.

The strength of a reinforcing substrate formed from a degradable plastic decreases with time. Therefore,
It is required to set the service life to 2-3 months. For this purpose, a three-layer structure shown in FIG. 2 in which a nonwoven fabric made of polypropylene is provided on both sides of the ventilation layer 20 as necessary, with the reinforcement substrates 11 and 12, respectively, is inserted and laminated between the reinforcement substrates. Is also performed.

In forming the protective sheet, usually, when forming a ventilation layer of microfibers, the reinforcing base material is transported in advance, and the surface of the reinforcing base material is entangled by spraying heated softened fibers onto the surface. This is performed by fixing by embossing or mirror finishing.

Hereinafter, the present invention will be described in more detail with reference to examples.

【Example】

(Example 1) Polypropylene-based nonwoven fabric soft (thickness: 20 µm, manufactured by Mitsui Petrochemical Industry Co., Ltd.) so as to form a gas-permeable layer 20 having a total thickness of 20 µm made of ultrafine long fibers of polypropylene.
2) is inserted and laminated between the reinforcing base materials 11 and 12, and the wood protecting sheet 1 according to the first embodiment of the present invention shown in FIG.
It was created.

(Example 2) As a breathable layer 20 having a total thickness of ultrafine long fibers of polypropylene of 30 μm, and a polypropylene-based non-woven soft (thickness: 25 μm, manufactured by Mitsui Petrochemical Co., Ltd.), reinforcing substrates 11 and 12 2. The wood protection sheet 1 of Example 1 of the present invention shown in FIG.
It was created.

(Example 3) A heat-sealable polyethylene-based Warif HS type (thickness: 20 µm, manufactured by Nisseki Koki Co., Ltd.) ) Was laminated as a reinforcing base material 11 to prepare the wood protection sheet 1 of Example 3 of the present invention shown in FIG.

(Comparative Example 1) A microporous sheet (thickness: 30 μm, manufactured by Nisseki Goju Co., Ltd.) formed by stretching polyethylene containing calcium carbonate as a gas-permeable layer 20, and polyethylene-based nonwoven fabric on both surfaces Warif (thickness 1
Embossed lamination was performed using 5 μm Nishiishi Goki Co., Ltd. as reinforcing substrates 11 and 12 to prepare a wood protection sheet 1 of Comparative Example 1 shown in FIG.

With respect to the samples of Examples and Comparative Examples, the following items, which are measures of practicality and durability, were tested immediately after production and as an accelerated test by an all-weather weather tester (WEL-2).
5X Suga Test Machine Co., Ltd.), 63 ° C., 18 minutes /
After a spray cycle of 120 minutes, the properties after 100 and 200 hours were evaluated. -Permeability (evaluation value through which water vapor permeates) Water pressure (related to water height and water repellency when water permeates the back surface,
Those having a high numerical value do not easily penetrate water.)-Changes in strength (breaking strength and elongation in the production direction MD and cross direction TD) were measured. Although the sheet of the sample of the example after the weathering test was brittle and collapsed, the sample of the comparative example remained in a form close to the original form.
Table 1 shows the results of the evaluation and measurement of the characteristic values. (Below)

[0029]

[Table 1]

The wood protective sheet made of a polyolefin resin of the present invention is water-repellent because of its material, so it is excellent in waterproofing effect and has a filtering property in spite of being breathable, and has an appropriate water pressure resistance. It has the effect of preventing bacteria from entering. And it has chemical resistance peculiar to polyolefin resin. And those using a photodegradable resin, especially a protective sheet made of polypropylene as a reinforcing base material, are light-degradable, brittle over time and easily disposed of, and are only those that have passed through the distribution process. In addition, it can be easily disposed of because it is naturally degraded by photolysis even in a production area.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a basic structure of a wood protection sheet of the present invention.

FIG. 2 is a schematic sectional view showing another configuration of the wood protection sheet of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Protective sheet 11, 12 Reinforcement base material 20 Vent layer

Claims (3)

[Claims] 1. Natural drying of raw wood and sawn from logs,
Further natural drying in the distribution process, in a wood protective sheet for producing timber to be used for processing of building materials and equipment, the sheet is a laminate of at least a breathable layer made of ultrafine fibers and a polyolefin-based reinforcing base material. A wood protection sheet, characterized in that: 2. A wood protection sheet, wherein the ventilation layer and the reinforcing base comprising the ultrafine long fibers according to claim 1 are mainly composed of polypropylene. 3. A wood protection sheet, wherein the ventilation layer and the reinforcing substrate comprising the ultrafine long fibers according to claim 1 are composed of a biodegradable plastic and / or a photodegradable plastic.