JP3790134B2 - Ultra high molecular weight polyethylene molded article with nonwoven fabric and method for producing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrahigh molecular weight polyethylene molded article with a nonwoven fabric and a method for producing the same.
[0002]
[Prior art]
Ultra-high molecular weight polyethylene is a kind of linear and highly polymerized olefin plastic, and has a molecular weight of 1 million or more as measured by a viscosity method. Ultra high molecular weight polyethylene has much higher impact strength than ordinary polyethylene due to its extremely high molecular weight, and has energy absorption capacity, tensile strength at high temperature, chemical resistance, corrosion resistance, physical and mechanical properties. Because it is remarkably superior, it is widely used in various fields such as various industrial machines, parts of vehicles, sports, leisure facilities, etc. as plates, blocks, films, round bars, square bars, odd-shaped products, molded products, etc. Yes.
[0003]
In the present specification, a plate, block, film, round bar, square bar, modified product, molded product, etc. made of ultra high molecular weight polyethylene are referred to as “ultra high molecular weight polyethylene molded product”.
[0004]
Ultra high molecular weight polyethylene moldings may be used by being fixed to such members in order to supplement the mechanical properties of members of different materials such as metal machine parts. As an example, as shown in the perspective view of FIG. 6, the ultra high molecular weight polyethylene sheet a may be used as a lining of a screw feeder b for sludge transfer of a mining machine. In the example of FIG. 6, the ultra high molecular weight polyethylene sheet a is fixed to the metal screw blade c of the screw feeder b by a bolt d. Ultra high molecular weight polyethylene has excellent wear resistance and excellent smoothness, and sludge is less likely to adhere compared to metal screw blade c. Therefore, ultra high molecular weight polyethylene sheet a is fixed to metal screw blade c. By using, sludge is smoothly transferred without adhering to the screw blade c.
[0005]
When the pitch of the screw blades c is relatively large as in the illustrated example, the ultrahigh molecular weight polyethylene sheet a can be bolted to the screw blades c, but if the pitch of the screw blades c is reduced, the bolting operation is difficult. Or it becomes impossible. In this case, the ultra high molecular weight polyethylene sheet a can be fixed by adhering it to the screw blade c. However, even if the ultra high molecular weight polyethylene sheet a is to be directly bonded to the screw blade c, the ultra high molecular weight polyethylene has extremely high smoothness, so that the adhesive does not adhere to the ultra high molecular weight polyethylene sheet a. Therefore, an ultrahigh molecular weight polyethylene sheet called a sheet with rubber has been commercially available.
[0006]
This rubberized sheet is made by baking the surface of an ultra-high molecular weight polyethylene sheet to remove surface flakes, and then applying an adhesive to the surface. A rubber plate is placed on an ultra high molecular weight polyethylene sheet and heated, and the rubber plate and the ultra high molecular weight polyethylene sheet are melted to laminate the rubber plate on the ultra high molecular weight polyethylene sheet. An adhesive is applied to the surface of the rubber plate of the rubber-equipped sheet and adhered to the surface of another member.
[0007]
[Problems to be solved by the invention]
However, this rubber-equipped sheet requires many steps for production and is costly, and only a relatively thin sheet having an ultrahigh molecular weight polyethylene sheet of about 1 to 10 mm can be produced. This is because the melting temperature and heat resistant time of rubber differ from the melting temperature and heat resistant time of ultra high molecular weight polyethylene, so if the thickness of the ultra high molecular weight polyethylene sheet is greater than 10 mm, the limit maximum temperature and heating time for melting the rubber This is because heat is not sufficiently transmitted to the entire ultrahigh molecular weight polyethylene sheet, resulting in uneven lamination of the ultrahigh molecular weight polyethylene sheet, resulting in poor lamination.
[0008]
In addition, the rubber-equipped sheet is relatively unsuitable for use in an environment where chemicals are used because the peel strength of the rubber plate is relatively weak and the chemical resistance is poor.
[0009]
The present invention has been considered in view of the above-mentioned problems in ultra-high molecular weight polyethylene moldings used by being bonded to different members, and can be manufactured by a simple manufacturing method, thereby reducing the manufacturing cost. It is intended to provide an ultra-high molecular weight polyethylene molded article that can be applied to a molded article having a thickness of 10 mm or more and has improved peel strength and chemical resistance.
[0011]
[Means for Solving the Problems]
The manufacturing method of the ultra high molecular weight polyethylene molding with a nonwoven fabric concerning this invention comprises the following process.
[0012]
(B) A process of laying a non-woven fabric on the lower mold of a molding die for compressing an ultra-high molecular weight polyethylene molded product from raw material powder (b) An ultra-high molecular weight polyethylene raw material having a molecular weight of 1 million or more in the lower mold laid with the non-woven fabric (C) The mold is closed and heated and pressed at a predetermined temperature and pressure to melt molten ultrahigh molecular weight polyethylene partially in the thickness direction of the nonwoven fabric. The process of entering into the fabric and intertwining with the fibers of the nonwoven fabric (D) The process of taking out the ultrahigh molecular weight polyethylene molded product with the nonwoven fabric from the molding die after the temperature of the molding die has dropped to room temperature.
[0013]
[Action]
According to the ultra high molecular weight polyethylene molded product with a nonwoven fabric according to the present invention, a part of the ultra high molecular weight polyethylene molded product on the side provided with the nonwoven fabric is partially in the nonwoven fabric in the thickness direction of the nonwoven fabric as a number of irregular projections. The structure in which the nonwoven fabric and ultra-high molecular weight polyethylene molded product are fixed to each other by entering and entangled with the fibers of the nonwoven fabric results in a marked increase in peel strength compared to a sheet with rubber, and it can also be used in places subject to strong impacts. In addition, since the nonwoven fabric is superior in heat resistance and chemical resistance compared to rubber, it can be used for a long period of time without being corroded in a high temperature environment or an environment where chemicals are used.
[0014]
In use, an adhesive is applied to the surface of the non-woven fabric, and the ultra high molecular weight polyethylene molded product with the non-woven fabric is bonded and fixed to the mating member so that the non-woven fabric faces the mating member.
[0015]
In addition, according to the method for producing an ultrahigh molecular weight polyethylene molded article with a nonwoven fabric according to the present invention, all steps are performed in a normal molding die for compression molding an ultrahigh molecular weight polyethylene molded article from a raw material powder, and a sheet with rubber There is no need for surface roughening work necessary for manufacturing, the process of manufacturing a rubber plate with a separate mold, and the process of applying an adhesive to the surface of an ultra-high molecular weight polyethylene molded product that has been surface-finished. It can be shortened, the adhesive can be omitted, and the manufacturing cost can be saved greatly.
[0016]
Further, since the nonwoven fabric is not melted in the heating and pressurizing step and only the ultra high molecular weight polyethylene molded product is melted, the heating temperature may be set according to the melting temperature of the ultra high molecular weight polyethylene molded product, and therefore the method according to the present invention. Can be applied to ultra-high molecular weight polyethylene moldings having a wide range of thickness exceeding 10 mm, without being limited to materials having an ultra-high molecular weight polyethylene molding thickness of 10 mm or less.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a perspective view showing an embodiment of an ultrahigh molecular weight polyethylene molded article with a nonwoven fabric according to the present invention. In this embodiment, the ultra high molecular weight polyethylene molded product is a plate made of ultra high molecular weight polyethylene.
[0018]
The ultrahigh molecular weight polyethylene plate 1 with a nonwoven fabric is an ultrahigh molecular weight polyethylene plate 3 that is provided with a nonwoven fabric 2 on one side and is formed of ultrahigh molecular weight polyethylene having a molecular weight of 1,000,000 or more as measured by a viscosity method. A portion of the ultra-high molecular weight polyethylene plate 3 on the side partially enters the nonwoven fabric 2 in the thickness direction of the nonwoven fabric 2 as a large number of irregularly shaped protrusions, and is entangled with the fibers of the nonwoven fabric 2 so that High molecular weight polyethylene plates 3 are fixed to each other.
[0019]
Hereinafter, the manufacturing method of this ultra high molecular weight polyethylene board 1 with a nonwoven fabric is demonstrated.
First, as shown in the cross-sectional view of FIG. 2, a non-woven fabric 2 having a predetermined size is laid on the entire surface of a lower mold 4a of a flat press mold 4 having a lower mold 4a and an upper mold 4b.
[0020]
Next, as shown in FIG. 3, the ultra-high molecular weight polyethylene powder 5 is filled to a predetermined thickness on the nonwoven fabric 2 laid on the lower mold 4a.
[0021]
Next, as shown in FIG. 4, the molding die 4 is closed, and as shown in the partial cross-sectional view of FIG. 5, the molding die 4 is mounted on the compression molding machine 6 to perform compression molding. In compression molding, after the preform 6a of the compression molding machine 6 is raised and pressurized at a predetermined pressure at room temperature, the preform 4 is heated at a predetermined temperature while being pressurized at a predetermined pressure. The ultra-high molecular weight polyethylene powder 5 is melted and impregnated in the nonwoven fabric 2, and after a predetermined time, it is forcibly cooled in a pressurized state and cooled to room temperature.
[0022]
As molding conditions, the pressure load is preferably 70 kgf / cm ² or more and 100 kgf / cm ² or less, the heating temperature 170 ° C. or more and 200 ° C. or less, the heating and pressing time 2 to 16 hours, and the cooling time 3 to 16 hours. If the heating temperature is low at the time of compression molding, the resin will not be melted completely, so that it will not be plasticized. Since the resin is exposed on the surface, even if an adhesive is applied to the nonwoven fabric, it becomes difficult to adhere to the other member to be fixed. When the pressure is insufficient, the resin is not plasticized, and when the pressure is excessive, the resin wraps around the surface of the nonwoven fabric, making it difficult to adhere to the mating member after molding. Therefore, in order to achieve complete adhesion to the mating member without causing separation when used as a product, the resin melted to the middle of the nonwoven fabric thickness is impregnated by appropriately adjusting the heating temperature and pressing load. It is best to do.
[0023]
After the compression molding is completed, the molding die 4 is removed from the compression molding machine 6, and the molding die 4 is opened to take out the molded product. By removing the burrs from the molded product, the ultra-high molecular weight polyethylene plate 1 with a non-woven fabric whose surface is the ultra-high molecular weight polyethylene plate 3 and whose back surface (adhesive surface) is the non-woven fabric 2 is completed.
[0025]
【The invention's effect】
According to the method for producing an ultrahigh molecular weight polyethylene molded article with a nonwoven fabric according to the present invention, all steps are carried out in a normal molding die for compression molding an ultrahigh molecular weight polyethylene molded article from a raw material powder. This eliminates the need for roughing the surface, the process of manufacturing the rubber plate in a separate mold, and the process of applying an adhesive to the surface of the ultra-high molecular weight polyethylene molded product that has been surface-treated, thus shortening the manufacturing process. Adhesives can also be omitted, and manufacturing costs can be saved greatly.
[0026]
Further, since the nonwoven fabric is not melted in the heating and pressurizing step and only the ultrahigh molecular weight polyethylene molded product is melted, the heating temperature may be set according to the melting temperature of the ultra high molecular weight polyethylene molded product, and therefore the method according to the present invention. Can be applied to ultra-high molecular weight polyethylene moldings having a wide range of thickness exceeding 10 mm, without being limited to materials having an ultra-high molecular weight polyethylene molding thickness of 10 mm or less.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of an ultra-high molecular weight polyethylene molded article with a nonwoven fabric according to the present invention.
FIG. 2 is a cross-sectional view showing a state in which a nonwoven fabric is laid on a molding die.
FIG. 3 is a cross-sectional view showing a state in which ultra high molecular weight polyethylene powder is filled in a molding die on a nonwoven fabric.
FIG. 4 is a cross-sectional view showing a state where a molding die is closed.
FIG. 5 is a partial cross-sectional view showing a state where a molding die is mounted on a compression molding machine.
FIG. 6 is a perspective view showing an example of how to use a conventional ultra-high molecular weight polyethylene molded product.
[Code]
DESCRIPTION OF SYMBOLS 1 Ultra high molecular weight polyethylene board with nonwoven fabric 2 Nonwoven fabric 3 Ultra high molecular weight polyethylene board 4 Mold 5 Ultra high molecular weight polyethylene powder 6 Compression molding machine

Claims (1)

A method for producing an ultra-high molecular weight polyethylene molded product with a nonwoven fabric comprising the following steps (a) A step of laying the nonwoven fabric on a lower mold of a molding die for compression molding the ultra-high molecular weight polyethylene molded product from raw material powder (b) Laying the nonwoven fabric The step of filling the lower mold with ultrahigh molecular weight polyethylene raw material powder having a molecular weight of 1 million or more to a predetermined thickness (c) The mold was closed and heated by pressurizing at a predetermined temperature and pressure for melting. Steps in which ultrahigh molecular weight polyethylene is partially entangled in the nonwoven fabric fibers in the thickness direction and entangled with the nonwoven fabric fibers. (D) Ultrahigh molecular weight polyethylene molded product with nonwoven fabric after the temperature of the mold has dropped to room temperature The process of taking out from the mold.

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