JPH01108022A - Manufacture of rolled macromolecular material sheet - Google Patents

Abstract

PURPOSE:To manufacture a macromolecular sheet product by rolling, by a method wherein one or two sets of pinch rollers are installed before and after a rolling machine and initial pass is effected by adding a forcing compressive force from the rear side of a material to bite it between the rollers while reciprocating rolling is effected while applying forward tension and rearward tension thereafter. CONSTITUTION:In initial rolling, in which the length of a material is short and the biting of the material is difficult, the material is pushed down slightly by pinching rollers 4 and the material is bitten between the rollers of a main rolling machine 3 while applying a forcing force on the material. When the material is bitten once, stable rolling is continued, therefore, it is not necessary to apply the forcing force. When rolling is advanced and the length of the material 2 is elongated, a rolling speed is regulated between the pinch rollers 4, 5 and the main rolling machine 3 to make the speed of the pinch rollers 4, located before the rolling machine 3, higher than the rolling speed of the rolling machine 3 or the speed of the pinch rollers 5, located after the main rolling machine 3, is made lower than the speed of the main rolling machine 3 whereby a tension is generated. According to the tension, the elastic restoring force is reduced and the drawing of the material is increased. According to this method, the macromolecular material may be drawn efficiently by the reduced number of passing.

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, pellet-shaped raw materials 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, then rolled continuously, and then tension is applied in the width direction to stretch the film to make it thinner and to have 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 these are markedly 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 nature of polymer material products, the scale of production equipment may increase, and efficiency and productivity may be severely reduced.
In order to efficiently manufacture polymeric material products, it is necessary to develop 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. That is, 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 for substantial stretching to occur. 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 In the present invention, when stretching a polymeric material by rolling, compressive force is applied from behind during the initial pass using one or two pinch rollers installed before and after the rolling mill. This is a method for producing a rolled sheet of a polymeric material, which is characterized by performing reciprocating rolling while applying forward tension and/or backward tension.

The present invention will be explained in detail below.

In general, the bite angle α of the material into the pair of rolls in rolling is p
There is a limit indicated by =tanα. As shown in FIG. 1, in order for the material 2 to be bitten between the rolling roll pair 1.1, the biting angle α in the contact arc between the rolls and the material must be such that the coefficient of friction between the roll l and the material 2 is If α≦jan=
It must be p.

Therefore, as in the rolling of polymeric materials, the smaller the friction coefficient L, the smaller the bite angle α. Although it is conceivable to increase the diameter of the roll l in order to reduce the bite angle α under a predetermined rolling reduction amount, it cannot be said to be economical in terms of equipment as described above. Another option is to forcibly push the material in with a pushing device, 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 invented the following method that enables pushing and tensioning.

Through many experiments, the inventors found that the smaller the diameter of the rolls used for rolling and the larger the rolling reduction per pass, the smaller the amount of elastic recovery. It was found that the increase in

That is, in rolling polymer materials, under light rolling.

Even if a large number of passes are repeated, hardly any stretching occurs, but if a large rolling reduction and tension are applied per pass, a large stretching can be obtained.

In order to achieve these conditions, one or two pinch rollers are installed before and after the main rolling mill, and the mill capacity of the pinch rollers is kept as small as possible, making the equipment compact.
Moreover, it is optimal to install the equipment close to the rolls.

An embodiment based on this arrangement will be described next.

During early rolling when the material is short and difficult to bite, a pinch roller is used to lightly reduce the material, and the main rolling mill applies pushing force to make it bite. -Once it is bitten, stable rolling continues, so there is no need to apply pushing force.

As rolling progresses further and the length of the material becomes longer, the roll speed is adjusted between the pinch rolls and the main rolling mill so that the speed of the pinch roll located in front is higher than the roll speed of the main rolling mill. Alternatively, create tension by slowing down the speed of the pinch roll located at the rear. This tension reduces elastic recovery and increases elongation.

In this way, the polymer material can be efficiently stretched with a small number of passes. Note that the tension exerted by the pinch rolls also has another effect; in rolling polymer materials, wavy deflections tend to occur during rolling, deteriorating the shape, but tension prevents this and improves the shape of the product. This enables stable rolling.

Example plate thickness: 10 mm, plate width: 200+am, length = 1
The polyethylene material of No. m could not be bitten with a roll having a roll diameter of 20 axial layers at a rolling reduction of 5 ms.

However, when we installed pinch rolls with a diameter of 100s + intestine at the front and rear, and set the pinch rolls to a rolling reduction of 1cm and the main rolling mill to a rolling reduction of 5mm, we found that
Rolling was possible.

After that, reverse rolling was performed using pinch rolls under lam reduction and tension, and the plate thickness was increased to 3 in 3 passes.
It was possible to stably roll a plate with a length of 3 m.

Effects of the Invention According to the present invention, polymeric materials such as polypropylene, polyethylene, and nylon can be stably and efficiently rolled in a rolling mill with compact equipment, resulting in high production of polymeric materials with excellent properties. Dice the effects that can be obtained during sex.

[Brief explanation of the drawing]

FIG. 1 is a sectional view illustrating the conditions under which material can be caught between a pair of rolling rolls, and FIG. 2 is an explanatory diagram showing the equipment arrangement when carrying out the present invention. l...Fist roll, 2-Member material N, 3-Fist φ main rolling mill, 4
,5...Pinch roller.

Claims (1)

[Claims] When stretching a polymeric material by rolling, one or two pinch rollers installed before and after the rolling mill apply compressive force from the rear during the initial pass, and then apply tension from the front and backwards. A method for producing a rolled sheet of polymeric material, the method comprising performing reciprocating rolling while applying tension or one of them.