Patent Application
20080026235
The nature of this invention, as well as other objects and advantages thereof, will be explained in the following with reference to the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures and wherein:
Embodiments of the invention will be described with reference to the attached drawings.
As illustrated in
The synthetic board 2 is molded by mixing lignocellulose-based material with polybutylene succinate-based resin (hereinafter referred to as PBS resin) or polylactic acid-based resin (hereinafter referred to as PLA resin) as adhesive, or alternatively with mixed resin containing the PBS resin and the PLA resin.
The lignocellulose-based material used here is plant-derived material in the form of fiber or powder, which is derived from wood or herbs, including lumber, bamboo and kenaf. Alternatively, plant-derived material that is fibrillated by being treated with alkali or lignocellulose-based material that is subjected to either steam or explosion treatment is used. The steam and explosion treatments make woody and herbaceous fibers easy to loosen. The steam and explosion treatments are carried out at high temperature and pressure, so that these treatments kill bugs, mold, bacteria and the like contained in the lignocellulose-based material and then improve preservability and durability. Especially the bamboo is excellent in antibacterial activity and relatively high in strength among natural fibers, so that it can increase rigidity and durability of the synthetic board.
The PBS resin is made of succinate and 1,4-butanediol which can be produced from plant-derived materials.
The PLA resin is synthesized from lactic acid obtained by fermenting sugar taken out of corn or the like.
The PBS and PLA resins may be in any state, such as fiber, powder, pellet, emulsion, and solution. However, the PBS and PLA resins usually have hydrolyzability and biodegradability, and if they are directly used for a vehicle interior member, a building component or the like, they make a product-life cycle short. Therefore, the hydrolyzability and the biodegradability are suppressed by mixing the PBS and PLA resins with polycarbodiimide resin as hydrolysis stabilizer and carrying out treatment such as end-capping. More specifically, in respect of humidity-and-heat resistance and biodegradability resistance of the synthetic board 2, tensile elongation after fracture of the synthetic board 2 is preferably 80% or more of an initial value after the synthetic board 2 is let stand for 480 hours in an environment where temperature and humidity are 50° C. and 90% RH, respectively.
The lignocellulose-based material and the PBS or PLA resin are mixed together by means of a mixer, such as a kneader, a roll, and a biaxial extruder, or by using a spray or the like. Alternatively, a fibrillating machine, a garnett machine or the like may be used to intertwine the fiber of the lignocellulose-based material and that of fibrous PBS or PLA resin. A needle punch or the like may also be used to form the lignocellulose-based material and the PBS or PLA resin into a preform shaped like a bulky mat. It is also possible to form the lignocellulose-based material in the shape of a bulky mat and spray the PBS or PLA resin onto the surface thereof.
The synthetic board 2 is molded by casting into a mold a mixture of the lignocellulose-based material and the PBS or PLA resin or mixed resin of the PBS and PLA resins, and heating and pressing the same.
The film 4 is made of transparent or colored polyester-based resin. For example, the film 4 is a PBS resin film, a PLA resin film, a resin film made of a mixture of the PBS and PLA resins, a resin film made of resin polymerized from dimer acid and 1,3-propanediol, a self-adhesive PET (polyethylene terephthalate) resin film, one side of which is applied with adhesive, a self-adhesive PP (polypropylene) resin film or a self-adhesive PA6 (polyamide 6) resin film. The PBS and PLA resin films are mixed with polycarbodiimide resin as hydrolysis stabilizer and carrying out the end-capping or the like, to thereby suppress the hydrolyzability and the subsequent biodegradability. A compounding ratio of the polycarbodiimide resin falls in a range of from 2 wt % to 10 wt %, and preferably from 2.5 wt % to 9.0 wt %.
In respect of the humidity-and-heat resistance and the biodegradability resistance of the film 4, tensile elongation after fracture of the film 4 is preferably 80% or more of the initial value after the film 4 is let stand for 480 hours in an environment where temperature and humidity are 50° C. and 90% RH, respectively.
The film 4 is affixed to the synthetic board 2 by a method including the steps of molding the synthetic board 2, placing the film 4 on the surface of the molded synthetic board 2, and heating and pressing the film 4, a method in which the molding of the synthetic board 2 and the affixment of the film are carried out at the same time by casting into a mold a mixture of the lignocellulose-based material and the PBS or PLA resin or of the lignocellulose-based material and the mixed resin containing the PBS and PLA resins, placing the film 4 thereon, and heating and pressing the film 4, or the like.
One example of specific methods for molding the synthetic board with a film according to the invention will be described below.
As illustrated in
A preform 2a shaped like a bulky mat, which is obtained by mixing the lignocellulose-based material with the PBS or PLA resin or with the mixed resin containing the PBS and PLA resins, is disposed, and the film 4 is placed on the preform 2a.
A sheet 12 made of PP is then placed on the film 4, and a stainless steel board 14 is disposed on the sheet 12.
The preform 2a and the film 4 surrounded by the spacer 10 and the stainless steel boards 6 and 14 are set in and pressed by a hydraulic press machine in which an upper and lower dies are heated beforehand, thereby molding a synthetic board with a film 1 in which the film is affixed to the surface of the synthetic board 2.
As described above, in the synthetic board with a film according to the invention, the PBS or PLA resin functions as adhesive, so that the molding of the synthetic board 2 and the affixment of the film 4 can be performed in one and the same process, which simplifies the work.
Accordingly, there is no waste of paints as in conventional spray painting, and complicated work such as baking process is not required. Consequently, the cost can be drastically reduced.
By forming the transparent or colored layer on the surface of the synthetic board 2 as described above, it becomes possible to improve light resistance, water resistance, humidity-and-heat resistance, wear resistance and the like of the synthetic board 2, and also to enhance appearance and design of the synthetic board 2.
Since the transparent or colored layer is formed on the surface of the synthetic board 2 by affixing the previously fabricated transparent or colored film 4 to the synthetic board 2, the transparent or colored layer is uniform and is unlikely to be mottled. For instance, it is easy to show a rough texture on the surface of the synthetic board 2.
As described above, the synthetic board with a film according to the invention not only eases burdens on the environment and humans but makes it possible to form the transparent or colored layer on the surface of the synthetic board through simple work, thereby improving the durability, appearance and design of the synthetic board.
Embodiments will be described below.
As a film, a green-colored film (“GS Pla” made by Mitsubishi Chemical; grade: AD92W) of 25 μm in thickness was used, the film being produced by mixing 85 wt % of PBS resin with 0.70 wt % of cyanine blue, 1.80 wt % of cyanine green, 0.80 wt % of carbon black, 0.16 wt % of titanium white, and 2.5 wt % of polycarbodiimide as hydrolysis stabilizer.
As lignocellulose-based material, bamboo fiber having a length ranging from 25 mm to 70 mm was used. The bamboo fiber was obtained by crushing and fibrillating bamboo through machining.
The bamboo fiber was mixed with PBS resin by means of a fibrillating machine, and a preform shaped like a bulky mat was fabricated.
The preform was put into a mold, and was heated and pressed by a hydraulic press machine, to thereby mold a synthetic board.
The green-colored film was placed on the synthetic board, and was subjected to heating and pressing again by the hydraulic press machine. As a result, there was produced a synthetic board with a film, which had a green surface with a rough texture of the bamboo fiber.
As a film, a deep blue-colored film (“TERRAMAC” made by UNITIKA) of 100 μm in thickness was used, the film being obtained by mixing 89 wt % of PLA resin with 6.00 wt % of cyanine blue, 0.40 wt % of quinacridone red, 0.70 wt % of carbon black, 2.00 wt % of aluminum pigment, and 2.5 wt % of polycarbodiimide as hydrolysis stabilizer.
As lignocellulose-based material, bamboo fiber having an average fiber length ranging from 10 mm to 90 mm was used. The bamboo fiber was obtained by crushing and fibrillating bamboo through machining.
The bamboo fiber was mixed with PLA resin by means of a fibrillating machine, and a preform shaped like a bulky mat was fabricated.
The preform was put into a mold, and the film was placed on the surface of the preform. The film and the preform were then heated and pressed by a hydraulic press machine so that molding of a synthetic board and affixment of the film were carried out at the same time. In this manner, there was produced a synthetic board with a film, which had a deep-blue surface with a rough texture of the bamboo fiber.
Used as a film was a transparent film (highly flexible-type film made by Toray Industries, Inc.) of 100 μm in thickness, which was polymerized from dimer acid and 1,3-propanediol.
As lignocellulose-based material, bamboo fiber having an average fiber length ranging from 10 mm to 90 mm was used. The bamboo fiber was obtained by crushing and fibrillating bamboo through machining.
The bamboo fiber was mixed with PLA resin by means of a fibrillating machine, and a preform shaped like a bulky mat was fabricated.
The preform was put into a mold, and the film was placed on the surface of the preform. The film and the preform were heated and pressed by a hydraulic press machine so that the molding of a synthetic board and the affixment of the film were simultaneously carried out. Consequently, there was produced a synthetic board with a film, which had a transparent surface layer and had a rough texture of the bamboo fiber.
As a film, a self-adhesive PET transparent film (“SOFTSHINE” made by Toyobo, Co., Ltd.; grade: A1535) of 50 μm in thickness was used.
As lignocellulose-based material, bamboo fiber having an average fiber length ranging from 10 mm to 90 mm was used. The bamboo fiber was obtained by crushing and fibrillating bamboo through machining.
The bamboo fiber was mixed with PLA resin by means of a fibrillating machine, and a preform shaped like a bulky mat was fabricated.
The preform was put into a mold, and the film was placed on the surface of the preform. The film and the preform were then heated and pressed by a hydraulic press machine so that the molding of a synthetic board and the affixment of the film were carried out at the same time. As a result, there was produced a synthetic board with a film, which had a transparent surface layer and had a rough texture of the bamboo fiber.
As a film, a self-adhesive PP transparent film (“TORAYFAN” made by Toray Industries, Inc.; grade: NL12) of 30 μm in thickness was used.
As lignocellulose-based material, bamboo fiber having an average fiber length ranging from 10 mm to 90 mm was used. The bamboo fiber was obtained by crushing and fibrillating bamboo through machining.
The bamboo fiber was mixed with PBS resin by means of a fibrillating machine, and a preform shaped like a bulky mat was fabricated.
The preform was put into a mold, and the film was placed on the surface of the preform. The film and the preform were subsequently heated and pressed by a hydraulic press machine so that the molding of a synthetic board and the affixment of the film were simultaneously carried out. Accordingly, there was produced a synthetic board with a film, which had a transparent surface layer and had a rough texture of the bamboo fiber.
As a film, a self-adhesive PA6 transparent film (“HARDEN FILM” made by Toyobo, Co., Ltd.; grade: NAP02) of 25 μm in thickness was used.
As lignocellulose-based material, bamboo fiber having an average fiber length ranging from 10 mm to 90 mm was used. The bamboo fiber was obtained by crushing and fibrillating bamboo through machining.
The bamboo fiber was mixed with PBS resin by means of a fibrillating machine, and a preform shaped like a bulky mat was fabricated.
The preform was put into a mold, and the film was placed on the surface of the preform. The film and the preform were then heated and pressed by a hydraulic press machine so that the molding of a synthetic board and the affixment of the film were carried out at the same time. In this manner, there was produced a synthetic board with a film, which had a transparent surface layer and had a rough texture of the bamboo fiber.
As lignocellulose-based material, bamboo fiber having an average fiber length ranging from 10 mm to 90 mm was used. The bamboo fiber was obtained by crushing and fibrillating bamboo through machining.
The bamboo fiber was mixed with PBS resin by means of a fibrillating machine, and a preform shaped like a bulky mat was fabricated.
The preform was put into a mold, and was heated and pressed by a hydraulic press machine. In this manner, a synthetic board was molded.
Green urethane paint was sprayed onto the surface of the synthetic board. The synthetic board was then made to pass through a baking oven for 5 minutes. As a result, there was produced a synthetic board with a surface, a rough texture of which was covered with green coating.
As a film, a PP transparent film (“TORAYFAN” made by Toray Industries, Inc.; grade: 2500) of 40 μm in thickness was used.
As lignocellulose-based material, bamboo fiber having an average fiber length ranging from 10 mm to 90 mm was used. The bamboo fiber was obtained by crushing and fibrillating bamboo through machining.
The bamboo fiber was mixed with PBS resin by means of a fibrillating machine, and a preform shaped like a bulky mat was fabricated.
The preform was put into a mold, and the film was placed on the surface of the preform. The film and the preform were subsequently heated and pressed by a hydraulic press machine so that the molding of a synthetic board and the affixment of the film were simultaneously carried out. However, the film failed to adhere to the synthetic board.
As a film, a PET transparent film (“TOYOBO ESTER FILM” made by Toyobo, Co., Ltd.; grade: E5000) of 38 μm in thickness was used.
As lignocellulose-based material, bamboo fiber having an average fiber length ranging from 10 mm to 90 mm was used. The bamboo fiber was obtained by crushing and fibrillating bamboo through machining.
The bamboo fiber was mixed with PBS resin by means of a fibrillating machine, and a preform shaped like a bulky mat was fabricated.
The preform was put into a mold, and the film was placed on the preform. The film and the preform were then heated and pressed by a hydraulic press machine so that the molding of a synthetic board and the affixment of the film were carried out at the same time. However, the film failed to adhere to the synthetic board.
As a film, a PET transparent film that was subjected to corona discharge treatment (“TORAYFAN” made by Toyobo, Co., Ltd.; grade: E5100) of 50 μm in thickness was used.
As lignocellulose-based material, bamboo fiber having an average fiber length ranging from 10 mm to 90 mm was used. The bamboo fiber was obtained by crushing and fibrillating bamboo through machining.
The bamboo fiber was mixed with PBS resin by a fibrillating machine, and a preform shaped like a bulky mat was fabricated.
The preform was put into a mold, and the film was placed on the surface of the preform. The film and the preform were subsequently heated and pressed by a hydraulic press machine so that the molding of a synthetic board and the affixment of the film were simultaneously carried out. However, adhesion force was so weak that the synthetic board and the film were easily detached from each other.
The synthetic boards with films according to Embodiments 1 to 6 and Comparative Examples 1 to 4 were analyzed in terms of appearance, design, VOC amount, coal-derived material usage, humidity-and-heat resistance, complication of work process, result of a 180-degree peeling test, and light resistance of the surface. Results of the analyses are shown in TABLES 1 and 2. The 180-degree peeling test measures adhesion force by peeling off an edge of the film affixed to the synthetic board and pulling the edge at an angle of 180 degrees. The analysis of light resistance of the surface analyzes color difference by using a light resistance testing machine after the synthetic boards with films are illuminated by ultraviolet light for 200 hours.
As shown in TABLE 1, the appearance and design of each of Embodiments 1 to 6 were good as the bamboo fiber was shown in the surface of the corresponding synthetic board.
In contrast, according to Comparative Example 1, the rough texture of the surface was covered with coating, and the texture of the bamboo fiber was not shown as presented in TABLE 2. In Comparative Examples 2 to 4, the films did not adhere to the synthetic boards. Consequently, there was no improvement in appearance and design.
Almost no VOC was detected in Embodiments 1 to 6 and Comparative Examples 2 to 4 in which the films were made of polyester-based resin. In Comparative Example 1 using urethane paint, however, a large amount of VOCs was detected.
The coal-derived material was used in a minimum amount in Embodiments 1 and 2 in which the films were made of plant-derived PBS and PLA resins, a small amount in Embodiment 3 using resin that was partially made of plant-derived material and polymerized from dimer acid and 1,3-propanediol, and a medium amount in Embodiments 4 to 6 and Comparative Examples 2 to 4 using the coal-derived PET-based resin, PP-based resin and PA6-based resin. In Comparative Example 1 using urethane paint, a large amount of coal-derived material was used because a great quantity of solution was required.
In respect of the humidity-and-heat resistance, Embodiments 1 and 2 using the plant-derived films containing hydrolysis stabilizer had fair humidity-and-heat resistance, whereas Embodiments 3 and 4 using the films made of the resin polymerized from dimer acid and 1,3-propanediol and the self-adhesive PET resin had good humidity-and-heat resistance. The humidity-and-heat resistance was excellent especially in Embodiments 5 and 6 using the self-adhesive PP resin film and the self-adhesive PA6 resin film and in Comparative Example 1 in which painting was provided. However, according to Comparative Examples 2 to 4 in which the films did not completely adhere to the synthetic boards, the humidity-and-heat resistance was poor for the reason that the bodies of the synthetic boards were not protected by the films.
Process in Comparative Example 1 requiring a baking process was complicated, while Embodiments 1 to 6 and Comparative Examples 2 to 4 involved a simple process of affixing the films by heating and pressing.
The 180-degree peeling strength was excellent in Embodiments 1 and 2 in which the films were made of the same material as the synthetic boards. Comparative Example 1 provided with painting was excellent as well (for instance, 7N/25 mm or more in 180-degree peeling strength). The films made of the resin polymerized from dimer acid and 1,3-propanediol and those made of the self-adhesive resin which is applied with adhesive on one side had good to fair adhesion properties. In contrast, Comparative Examples 2 to 4 in which the films did not adhere to the synthetic boards were poor in adhesion properties.
The light resistance of the surface was fair in Embodiments 1 and 2 using the plant-derived PBS and PLA resin films and Embodiment 6 using the self-adhesive PA6 film. Embodiments 3 to 5 and Comparative Examples 1 to 4 had good light resistance of the surface.
As to the prevention of odor emission, Comparative Example 1 provided with painting was poor, whereas Embodiments 1 to 6 and Comparative Examples 2 to 4 in which the films were affixed were good.
It was found that, as described above, if the entire synthetic board with a film was made of plant-derived material by using a plant-derived film as in Embodiments 1 and 2, it was possible to suppress the coal-derived material usage to a minimum amount and then to make the synthetic board environmentally excellent. The analyses also revealed that if the film was made of the same material as the synthetic board, it became possible to ensure strong adhesion force.
It was also found that, by using a coal-derived film applied with adhesive on one side thereof as in Embodiments 3 to 6, it became possible to maintain relatively good adhesion properties and at the same time to fully enhance the humidity-and-heat resistance and light resistance of the synthetic board with a film.
Although the embodiments of the synthetic board with a film according to the invention have been described, embodiments are not limited to the above-described ones.
For instance, although the synthetic board is molded by heating and pressing in each of the embodiments, molding means is not limited to the heating and pressing molding. The synthetic board may be molded, for example, by injection compression molding or the like.
The above embodiments present the case in which the bamboo fiber obtained by crushing and fibrillating bamboo through machining is used as lignocellulose-based material. The lignocellulose-based material, however, is not limited to the bamboo fiber in the invention. For example, ordinary kenaf or hemp may be used as the lignocellulose-based material.
The invention thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-208015 | Jul 2006 | JP | national |
