JPH01108027A - Manufacture of rolled macromolecular material sheet - Google Patents

Abstract

PURPOSE:To manufacture a macromolecular sheet product by rolling, by a method wherein the rolling of an initial direction is effected by forming a recess at the end of a material to apply a tension to the material and the subsequent rolling of the other direction is effected by applying the tension through a friction force generated by a pressing jig. CONSTITUTION:The middle part of a material is advanced to a gap between a couple of rolls, having a small diameter allowable practically, thereafter, the rolls 3 are pushed down and set so as to keep a predetermined gap, then, the fore end 4 and the rear end 5 of the material are clamped by tension applying devices 6, 7 under this condition, and the rolls are rotated from this condition to effect rolling. In order to clamp surely in a short period of time, recesses 12 are formed previously at the end of the material 2 and the end of the material is clamped by the jig 13, which can be engaged with the recesses well. When the thickness (t) of the recessed part is selected properly, the material will never be cut off by the tension. Subsequently, the material is cut lengthwisely to roll it into a direction orthogonal to the initial rolling direction. The material is preferably provided with a tension when the cut material is rolled. In this case, the material is pushed through a retaining plate and a frictional force is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to a method for manufacturing plate-shaped products by rolling polymeric materials.

Conventional technology Currently, there are many types of polymer material products.
The manufacturing method differs depending on each type. In many cases, raw materials in the form of pellets are melt-extruded at a predetermined temperature and processed into various shapes. Some of them are further processed into products.

For example, a photographic film is extruded into a plate shape and then rolled continuously, and then tension is applied in the width direction to stretch the film and make it thinner, resulting in a film with improved strength. However, this method is complicated in manufacturing thicker plate products, which is the objective of the present invention, because the rolling equipment becomes too large and a large tension in the width direction is required. There are problems such as the need for a tension device.

To obtain a thick plate-like polymer material with high strength,
A method of stretching the material by rolling in two directions is useful. As a technique for biaxially stretching a polymer material by rolling, for example, Japanese Patent Application No. 81-123435
There is a method proposed in No. However, this method also has problems that need to be solved, such as low productivity and excessive equipment.

Problems to be Solved by the Invention When trying to stretch a polymeric material by rolling, it is conceivable to apply the rolling technology used in steel, etc. However, as a result of many attempts, the inventors have found that The properties of are significantly different.

It was discovered that simply applying the conventional rolling technology used in the iron industry as it is would not be a sufficient solution.

In other words, due to the unique properties of polymer materials, the scale of production equipment may increase, and efficiency and productivity may be extremely reduced.
In order to efficiently manufacture a single polymer material, it is necessary to develop a unique rolling technology.

The main reason why steel rolling technology cannot be applied to rolling polymer materials is the low friction coefficient and large elastic recovery phenomenon of polymer materials. Namely, 1. Under normal conditions, the material is difficult to get caught in the rolls, and even after getting caught, the amount of recovery is large, making it difficult to cause substantial stretching. That is, in rolling when the material is still thick, a large number of passes are required, resulting in an extremely low productivity. In order to make it easier to bite the polymer material, it is possible to increase the diameter of the roll, but this would require huge equipment and would be impractical.Additionally, it may be necessary to apply tension, but this is not suitable for rolling with small material lengths. There are some difficult points.

The present invention solves such problems in the prior art,
The purpose of the present invention is to provide an industrial process for producing polymeric plate-shaped products by rolling.

Means for Solving the Problems The present invention provides a method for sequentially stretching a polymeric material in two directions by restraining the leading and trailing ends of the material so that no tension is applied. In the rolling method, in the first direction rolling, a recess is formed at the edge of the material to add tension, and in the subsequent rolling in another direction, tension is added by frictional force due to the holding force of a jig. This is a method for manufacturing a rolled plate made of a polymeric material.

The present invention will be explained in detail below.

Generally, in rolling, the bite angle α of the material into the roll pair is g
There is a limit indicated by =tanα. As shown in FIG. 1, in order for the material 2 to be bitten between the pair of rolling rolls l, 1, the biting angle α in the contact arc between the rolls and the material must be
If the coefficient of friction between roll l and material 2 is t, then α≦ja
Must be n””IL.

Therefore, as in the rolling of polymeric materials, when the friction coefficient is small, the bite angle α becomes small. It is conceivable to increase the roll diameter in order to roll with a smaller bite angle α under a predetermined rolling reduction amount, but in this case, as mentioned above, it cannot be said to be economical in terms of equipment. Another possible method is to forcibly push the material in with a pushing device to increase the bite angle α, but this requires another dedicated device. In both cases, the biting situation is unstable and the theoretical maximum biting amount cannot be achieved in many cases.

The inventors have discovered the following method in order to realize a highly productive polymer material rolling process.

Through many experiments, the inventors found that the smaller the diameter of the rolls used for rolling and the larger the amount of reduction, the smaller the amount of elastic recovery, and the fact that the amount of elastic recovery is reduced by applying tension. I found out.

That is, even if a large number of passes are repeated under light rolling, hardly any stretching occurs, and applying a large rolling reduction in one pass without applying tension makes large stretching possible. However, reducing the roll diameter makes biting more and more difficult.

Therefore, the inventors focused on the fact that the object to be rolled was a polymeric material, and using rolls with a small diameter that was actually allowed, first, the middle part of the material was advanced to between the open pair of rolls, and then,
As shown in Fig. 2, the roll 3 is rolled down to set a predetermined gap, and in this state, the front end 4 and rear end 5 of the material are restrained by the tension applying device 6.7, and then the roll is rotated from this state. , rolling was carried out. However, at this time, the rolling efficiency is greatly influenced by the restraining method.

Various methods can be considered for the restraint, and as shown in FIG. 3, the material 2 may be fastened with a bolt 8 via a stop plate 9, but it takes time to attach the material 2.

This is not appropriate when emphasis is placed on productivity.

In order to securely and quickly fasten the material, a recess 12 is formed in advance at the end of the material 2, as shown in FIG.

This can be done immediately by using a jig 13 that fits this. If the thickness t of the recessed portion is appropriately selected, the recessed portion will not be cut due to tension, and the recessed portion may be formed by machining, press molding, or a plurality of recessed portions.

After the predetermined stretching has been applied in this manner, it is subsequently cut in the longitudinal direction for rolling, for example in a direction perpendicular to this.

Tensioning is also desirable in rolling cut material for the same reasons discussed above.

However, when there is no time to spare, the fastening method that forms a recess like the one described above can be used without tension, as shown in Figure 5, when the wall thickness is sufficiently small. In structure, for example.

A ram 18 is moved by a hydraulic or mechanical pressure device 15 to press down the material through the stop plate 14 and generate a frictional force. Of course, in order to increase the frictional force, it is necessary to appropriately select the roughness of the surface. In this way, the tension can be sufficiently withstood by the frictional force caused by the pressing force.

The reason why the fastening method is changed depending on the thickness can be explained as follows.

Frictional force Q = Presser force P x Friction coefficient Presser foot pressure p x Contact surface @ S x Friction coefficient The required tension T is proportional to the plate thickness at that time, so the smaller the thickness t, the greater the friction force due to the presser foot. becomes relatively large to reach the required tension.

Conversely, when the thickness is large, it is necessary to press a large area with a large pressing force, but since the area of the material is limited and the pressing force must be kept below the deformation stress, it is practically impossible to apply tension. Become.

As a result of many experiments, the inventors have found that in the case of polymeric materials, although it varies depending on the material, in most cases, when the number of layers is 10 or less, frictional force is sufficient to achieve the purpose. Of course, if the surface of the presser plate is knurled, its applicability will be wider.

By doing so, stable rolling is possible and the maximum bite angle can be achieved.

The magnitude of tension also depends on the rolling conditions, but
In terms of stress, it is usually 30% or less of the deformation resistance at most. The direction of rolling may be either.

This method is difficult to implement in cases such as thermal 11R steel because of the drop in material temperature or damage to the rolls, but in the case of polymeric materials, the material is difficult to lose heat,
It is easily carried out because the rolls are also kept warm.

Note that the method of the present invention may be applied not only to the first pass but also to subsequent passes.

In the example, a polyethylene material having a plate thickness of 20 mm and a plate width of 1000 mm had a roll diameter of 200 layers and a rolling reduction of 5 mm, including +tB. However, by applying the terminal method, i.e. by forming a recess with a depth of 5 intestinal layers at the end,
It was restrained with a tensioning device and rolled with a reduction of 5 liters, and it was rolled to 10 layers in 5 passes. Next, when cutting this into 1000 m long layers and performing the next rolling, the parts located at the previous width were fastened by frictional force, and it was possible to roll to 5 m koji in 3 passes.

Effects of the Invention According to the present invention, polymeric materials such as polypropylene, polyethylene, nylon, etc. can be stably and efficiently rolled using a rolling mill with a small roll diameter.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the engagement angle, Fig. 2 is a schematic diagram of the procedure of the present invention, Fig. 3 is a sectional view of the fastening method using bolts, and Fig. 4 is a schematic diagram of the procedure of the present invention.
5 are cross-sectional views showing the fastening method of the present invention. lΦ・φ roll, 2## body material, 3#-・roll, 4.
5...Both ends of the material, 6.7...Tension applying device, 8.
... Bolt, 9... Holding plate, 12... - recess,! 3
11Φ・Press tool, 14φ・Press plate, 15-・Press force generator, IB...Ram.

Claims (1)

[Claims] When a polymeric material is sequentially stretched in two directions by rolling, the leading and trailing ends of the material are restrained and tension is applied while reverse rolling is performed. 1. A method for producing a rolled sheet of a polymeric material, comprising: forming the rolled sheet, applying tension, and applying tension during subsequent rolling in another direction using frictional force caused by a holding force by a jig.