JPH0653401B2 - Method for producing ultra high molecular weight polyethylene lining roll - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing an ultrahigh molecular weight polyethylene lining roll used for various rolls such as a compression roll, a transport roll, a table roll, and a carrier roll. For details, in order to prevent noise, prevent corrosion, or prevent damage to processed products, the outer surface, that is, the outer surface of the roll is made of resin. The present invention relates to a roll manufacturing method which is excellent in abrasion resistance, impact resistance and chemical resistance and does not damage a processed product.

(Prior Art) A roll lined with resin on the outside has flanges at both ends of a metal rod-shaped body or a metal tubular body having strength, and the resin tubular body is press-fitted or shrink-fitted onto a metal roll base provided with a shaft. It was manufactured by fitting and fixing by a method such as the above, and grinding finish the outer periphery.

Further, as disclosed in JP-A-53-39362, a heated resin tubular body is arranged outside a metal base roll, and a liquid resin such as urethane is placed between the metal base and the resin tubular body. A method of injecting, curing and fixing is also proposed.

As the resin used for the tubular body, so-called general-purpose resins such as polyacetal, polycarbonate and nylon are used.

Furthermore, the present inventors have already extruded and once cooled the ultrahigh molecular weight polyethylene tubular body as a method for producing an ultrahigh molecular weight polyethylene lining roll to reheat it to a crystallization temperature or higher to thermally expand it, so that the inner diameter is a roll base. A method has been proposed in which the roll base is fitted in a state where the diameter is larger than the outer diameter of the body, and then the roll base is cooled and contracted to be fixed to the roll base.

(Problems to be Solved by the Invention) According to the conventional shrink-fitting and press-fitting methods, each resin has its own elasticity and coefficient of thermal expansion. Therefore, it is necessary to improve the surface smoothness and dimensional accuracy of the metal serving as the roll base. On the other hand, the inner surface of the resin cylindrical body that is press-fitted or shrink-fitted also requires time and labor to process it in order to improve its finishing accuracy. Moreover, when the shrink fitting and press fitting allowances of the resin tubular body are not properly taken into consideration by taking into consideration the correlation between the roll diameter of the metal base and the resin thickness at the time of shrink fitting and press fitting, the resin is shrink fitted and fits during the press fitting. There is a defect that it is impossible to insert the resin, or the resin is cracked or damaged after the resin is inserted.

Further, the method of placing a heated resin tubular body on the outside of the metal base roll, injecting a liquid resin such as urethane between the metal base and the resin tubular body, and curing and fixing the resin takes time to manufacture. There are drawbacks.

Further, when a general-purpose resin is used as the resin for the tubular body, there is a defect in any of impact resistance, abrasion resistance and chemical resistance.

Further, it has been found that the method for producing an ultra-high molecular weight polyethylene lining roll proposed by the present inventors requires an excessive heating device when the roll size is large, resulting in large heat energy consumption.

The present invention is to improve such a point, and does not require processing for improving the smoothness and finish dimensional accuracy of the outer surface of the roll substrate, and has impact resistance, abrasion resistance, chemical resistance and durability. It is intended to provide a method capable of producing a roll lined with ultra-high molecular weight polyethylene having an excellent outer surface faster and with a small heat loss.

(Means for Solving the Problems) That is, the present invention provides a method for producing an ultra-high molecular weight polyethylene lining roll having a structure in which a tubular body of ultra-high molecular weight polyethylene is fitted into a tubular or rod-shaped roll base. A molecular weight polyethylene was molded into a tubular body by a ram extruder, the tubular body was cut while being held at a crystallization temperature of the ultrahigh molecular weight polyethylene resin or higher, and the tubular body was fitted into a roll substrate and then cooled. A method for producing an ultra-high molecular weight polyethylene lining roll characterized by shrinking.

Hereinafter, specific embodiments of the present invention will be described in detail.

FIG. 1 is a sectional view of a ram extruder used in the method of the present invention, and the ram extruder is of a generally known plunger type. In the figure (1) is a cylindrical cylinder,
A raw material supply part (2) is installed near the rear end of this cylinder, and a plurality of heating devices (3a) are installed on the surface of this cylinder.
(3b) is installed. From the rear end side of the cylindrical cylinder (1), a ram (5) that reciprocates by a predetermined movement width is inserted by a hydraulic device (4) installed at the rear end, and a rod-shaped mandrel (6) is inserted at the tip of the ram. ) Is attached.

Here, the dimensions of the extruded tubular body (13) are cylinder
It is regulated by the inner diameter of (1) and the outer diameter of the rod-shaped mandrel (6). In addition, the extrusion speed during extrusion must be appropriately adjusted by the inner diameter of the cylinder (1) of the ram extruder, the outer diameter of the rod-shaped mandrel (6), the length, and the temperature of the heating devices (3a) (3b). In the case of the present invention, the temperature of the heating device for the cylinder is set to 150 to 300 ° C, preferably 180 to 250 ° C. If the temperature is 300 ° C or higher, the ultrahigh molecular weight polyethylene deteriorates due to thermal decomposition, and if the temperature is 150 ° C or lower, the extrusion pressure becomes excessive, and in extreme cases, extrusion molding is not possible, which is not preferable.

Further, in the ram extruding device, a cover member (9) is arranged between the cylindrical cylinder (1) and the heat insulating hood (12) to hold the temperature of the extruded cylindrical body (3) and to maintain a constant length. It is a place to cut the molded body extruded into. This cover member (9)
Is fixed to the outlet of the cylinder (1) of the ram extruder via a cylindrical heat-resistant canvas (8) by a connecting flange (7) having a structure that is easily removable.

Further, the heat insulating hood (12) is installed to keep the extruded cylindrical body (13) at a predetermined temperature, and inside the extruded cylindrical holding base (10) and the end portion. An outlet (11) including a lid that can be opened and closed is attached to this.

In the present invention, the ultra-high-molecular-weight polyethylene tubular body having a crystallization temperature or higher shrinks when cooled to the crystallization temperature or lower, so that a tubular body having a length in which the shrinkage length is added to the roll base length is extruded. Then, at this time, the connecting flange (7) is removed, and it is cut at the portion A and immediately taken out from the outlet (11).

Then, as shown in FIG. 2, the tubular body (13) cut at a predetermined length and having a predetermined temperature is fitted into a roll base (15) prepared in advance. (15) is installed vertically. However, when the roll base length is large, the roll base (15) is installed horizontally by fixing the shaft attached to one end.

After that, when the tubular body (13) is cooled at 50 ° C. or lower for 3 hours or more, the tubular body (13) strongly adheres to the roll base (15). The cooling condition is not limited to this, and water cooling is also possible.

The ultrahigh molecular weight polyethylene referred to here is a general-purpose polyethylene of about 60 to 300,000 by the light scattering method and 2 to 10 by the viscosity method.
For a molecular weight of about 10,000, it shows an extremely large value of 3 million or more by the light scattering method and 1 million or more by the viscosity method.
Compared with general-purpose polyethylene and plastics, it has excellent impact resistance, abrasion resistance and crack resistance, and is a resin suitable for use on the outer surface of rolls.

In addition, the ultra high molecular weight polyethylene has a very large molecular weight, and when it is heated at a crystallization temperature (crystallization melting temperature) of 135 to 138 ° C. or higher and 200 ° C. or lower, it has a property similar to that of a crosslinked resin. Even if a tubular body that hardly flows and exhibits rubber-like elasticity and is extruded by a ram extruder is kept at a temperature higher than the crystallization temperature, its shape hardly changes.

Further, since ultra-high molecular weight polyethylene having a crystallization temperature or higher has a property of shrinking by 3 to 6% when cooled to room temperature, it is possible to easily insert the roll substrate without sufficiently improving the finishing dimensional accuracy of the outer surface of the roll substrate. Moreover, the ultra-high molecular weight polyethylene tubular body has a property of shrinking when cooled, and thereby strongly adheres to the roll substrate.

Since the outer circumference of the finished roll lacks dimensional accuracy or smoothness, the outer peripheral surface is cut.

Moreover, the ultra-high-molecular-weight polyethylene tubular body mentioned here can be used as an ultra-high-molecular-weight polyethylene material that has been crosslinked with an organic peroxide or the like, or has been modified by adding a filler or the like.

Further, the roll base body here is a rod-shaped or tubular body, and a metallic roll formed by attaching a flange to both ends of a metal tubular body having strength from the viewpoint of strength, rigidity or cost and forming a shaft on this. Is.

Next, the present invention will be described in detail with reference to specific examples, but the present invention is not limited thereto.

(Example) Inner diameter φ1 whose outer circumference was adjusted to 200 ° C. by an electric heater
External diameter φ1 in a cylinder of 45 mm and heating section length of 1,000 mm
A ram extruder with a 17 mm mandrel inserted at the outlet has a holder and an outlet, the outer circumference of which is heated by an electric heater to keep the internal temperature at 150 ± 10 ° C.
Ram Extruder (shown in FIG. 1) in which a hood with a temperature of 000 mm is connected through a cover member made of tubular glass canvas.
With ultra high molecular weight polyethylene powder (Hoechst
Hostalen GUR # 415) was extruded into a tubular body. This ultra-high molecular weight polyethylene tubular body had a surface temperature of 160 ± 5 ° C. at the cylinder outlet, an outer diameter of φ145 ± 1 mm, and an inner diameter of φ117 ± 1 mm, and there was almost no dimensional change up to the outlet of the heat insulating hood.

Further, an iron roll base material was prepared in advance, in which a cylindrical portion having both end flanges and a shaft attached thereto had a length of 1,800 mm and an outer diameter of 115 mm.

The ultra-high molecular weight polyethylene tubular body obtained by the above method was cut at the cylinder outlet at the time of extrusion molding about 1,900 mm, immediately taken out from the heat-insulating hood, fitted into the roll base, and allowed to cool at room temperature for 3 hours or more. By doing so, it was contracted and fixed.

The finished lining roll has an outer diameter of φ135 mm and both ends are cut to the length of the base body, and finish processing is performed. As a result, the lining material is firmly adhered to the roll base body and No movement such as relative rotation was observed between the roll base and the roll, and the durability was about 3 times that of the nylon lining roll.
The molding speed of the ultra-high molecular weight polyethylene cylinder is 1.2.
It was m / hr, and it was possible to perform lining molding at a rate of 1 per 95 minutes.

(Comparative Example) A ram extruder equipped with the same cylinder and mandrel as in the example did not have a heat insulating hood. Using this ram extruder, an ultrahigh molecular weight polyethylene cylinder was continuously extruded. This cylindrical body cooled to near room temperature
Cut to a length of mm.

This ultra high molecular weight polyethylene cylinder has an outer diameter of 141 mm,
It has an inner diameter of φ113 mm, and it is necessary to heat and thermally expand it for the purpose of fitting it into the same roll base material as in the example.
It was necessary to reheat in a 0 ° C. hot air oven for 30 minutes or more, and when the roll was long, an excessively hot air oven was required, which was inefficient in terms of energy.

(Effect) As described above, in the production method of the present invention, the step of cooling and reheating the extruded ultrahigh molecular weight polyethylene tubular body is omitted. The time required for forming can be shortened and the heat energy for reheating can be omitted. Furthermore, it is not necessary to perform processing to enhance the smoothness of the outer surface of the roll base or the finishing dimensional accuracy, and it has impact resistance and wear resistance. It is possible to manufacture an ultra-high molecular weight polyethylene lining roll that has excellent properties, chemical resistance and durability, and has an excellent outer surface that does not move because the lining material on the outer periphery of the roll is strongly fixed to the roll substrate. Have an effect.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a ram extruder used in the method of the present invention, and FIG. 2 is a partially cutaway cross-sectional view showing one step of fitting a roll base into an ultrahigh molecular weight polyethylene tubular body in the present invention. . (1) …… Cylindrical cylinder (9) …… Cover member (12) …… Heat insulation hood (13) …… Ultra high molecular weight polyethylene cylinder (15) …… Roll substrate

Claims (2)

[Claims] 1. A method for producing an ultrahigh molecular weight polyethylene lining roll having a structure in which a tubular body of ultrahigh molecular weight polyethylene is fitted into a roll substrate, wherein ultrahigh molecular weight polyethylene is formed into a tubular body by ram extrusion, A method for producing an ultra-high molecular weight polyethylene lining roll, characterized in that the tubular body is cut at a crystallization temperature of the ultra-high molecular weight polyethylene resin or higher, the tubular body is inserted into a roll base, and then cooled and contracted. . 2. The ultra-high molecular weight polyethylene tubular body to be molded has an inner diameter larger than the outer diameter of the roll substrate by 0.1 to 6% in the temperature range of 140 to 200 ° C. Item 1. A method for producing an ultrahigh molecular weight polyethylene lining roll according to item 1.