JPH0284316A - Manufacture of rolled late made of polymer material - Google Patents

Abstract

PURPOSE:To enhance productivity by minimizing a rolling time by altering either one or more of various conditions so as to preliminarily estimate the temp. of a rolling material on the basis of a rolling condition to hold the rolling material to an objective temp. CONSTITUTION:In performing rolling, the temp. of a material of each pass is preliminarily calculated from a calculation model formula based on each of rolling conditions and the material is rolled within the min. time preventing the melting of the material. As rolling conditions, the initial temp. of the material, the dimension thereof, the diameter of a roll, a draft rate of each pass, the temp. of the roll, a rolling speed, a stand-by time between respective passes or the like are considered and three alterable conditions of the rolling speed, the draft rate and the stand-by time between respective passes are determined under a condition of minimizing the time required in total production. A polymer material can be rolled efficiently within the min. time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a plate-shaped product by rolling a polymeric material.

[Prior art] Currently, there are many types of polymer materials, and although the manufacturing method differs depending on the type, in most cases, raw materials in the form of pellets are melted at a predetermined temperature. It is extruded and processed into various shapes. Some things are further processed, such as photographic film, which is extruded into a plate shape and then processed.
The film is continuously stretched using rolls, and then tension is applied in the width direction and the film is stretched to become thinner and stronger.

However, this method requires excessively large rolling equipment, requires a large tension load in the width direction, and requires a complicated tensioning device in the production of thicker plate-like products, which is the objective of the present invention. Therefore, it cannot be practical and cannot be applied.

Therefore, in order to obtain these thick plates, it is necessary to stretch the material by rolling in two directions, as is done, for example, in the steel manufacturing field. As a technique for stretching a polymeric material in the 2@ direction by rolling, for example, there is a technique proposed in Japanese Patent Application No. 123435/1982.

However, this technique also has problems that need to be solved, such as low productivity.

[Problem to be solved by the invention] When trying to stretch a polymeric material by rolling, it is possible to apply the rolling technology used in steel, etc., but as a result of many attempts, the inventors have found that It was discovered that the properties of polymers and polymers are so different that it is impossible to deal with them simply by applying conventional manufacturing technology in the iron field.

In other words, the scale of production equipment has increased, and efficiency and productivity have been severely reduced.In order to obtain an efficient manufacturing method for polymeric materials, it is necessary to develop unique rolling techniques that are tailored to the characteristics of the material. There is a need to.

The main reason why steel rolling technology cannot be applied directly to rolling polymer materials is the specific heat of the polymer material.
It has remarkable thermal conductivity and deformation resistance, which is different from steel. That is, when a polymeric material is rolled under normal rolling conditions for steel or non-ferrous metals, the material melts at a certain reduction rate or speed and becomes impossible to roll.

Even in the rolling of steel, temperature increases may occur under continuous and high speed conditions, but the amount is small and not on the order of impeding the rolling process. Rather, the heat from processing functions to compensate for the decrease in material temperature due to cooling.

The purpose of the present invention is to provide an industrial process for rolling polymeric materials that solves these problems, minimizes rolling time, and increases productivity.

[Means for Solving the Problems] The present invention is characterized in that, in a method for manufacturing a rolled plate made by stretching a polymer material by rolling, the temperature of the material during rolling is estimated in advance based on the rolling conditions. Then, melting of the rolled material is prevented by changing any one or more of the line speed, rolling reduction rate, and waiting time between passes so that the rolled material is maintained at the target temperature. While
A rolling method characterized by performing multiple passes of rolling in a minimum time.

The present invention will be explained in detail below.

As mentioned above, for example, the specific heat, thermal conductivity, and deformation resistance of polyethylene are shown in Table 1 in comparison with those of steel (1200° C.). As you can see, compared to the difference in deformation resistance between the two, the specific heat of the polymer material is extremely large and its thermal conductivity is low. Or even if it is radiated, the heat in the center of the material is not transferred to the surroundings, and the temperature of the material mostly increases, which affects the next pass.

Table 1 (]) cal/g”C(2) kcal/mh”C(
3) kg/mm2, that is, if polyethylene is rolled at a rolling temperature of, for example, 140°C, the melting point may easily reach 168°C after several passes of rolling.

The characteristic values of such materials are common to polymer materials, and
Therefore, this is a phenomenon that occurs not only in the rolling of polyethylene but also in polymeric materials.

Of course, this can be avoided by allowing sufficient time to cool down the material temperature after one pass of rolling, but this would not be possible in industrial manufacturing where a certain production efficiency must be achieved. It cannot be a process.

The present invention is a method of rolling with minimum rolling time in consideration of such productivity.

That is, when rolling, the material temperature for each pass is determined in advance using a calculation model formula based on the rolling conditions, and the material is rolled in the minimum time so as not to melt. The rolling conditions include the initial material temperature, material dimensions, roll diameter, rolling reduction rate of each pass, roll temperature, rolling speed, waiting time between each pass, etc., and there are three conditions that can be changed: rolling speed, rolling reduction rate, The inter-pass waiting time is determined based on the minimum time required for total manufacturing. The procedure is shown in FIG.

Additionally, in order to improve calculation accuracy, the material surface temperature may be measured and the calculation results may be corrected.

In addition, even in steel rolling, there are examples of determining the optimal rolling conditions by calculating the material temperature based on the rolling conditions with the aim of maximizing efficiency, but this is done to improve the accuracy of plate thickness. However, it is impossible to keep materials on standby. It should be added that, as mentioned above, the first object of the present invention is to avoid the inability to roll due to melting, which is a unique phenomenon of rolling polymer materials.

[Example] Plate thickness: lO+nm, plate width: 200 mm, length = 1 m,
Roll diameter: 200 mm, rolling speed: 30 m/min, first pass, 10 → 5 o + m, rolling reduction rate 50 *, waiting time 5 seconds, second pass, 5 → 4 mm rolling was completed, Melting occurred in the second pass, making rolling impossible.

Therefore, according to the model formula, the calculation result was that the rolling speed was 15 m.
The following conditions were calculated: 7 minutes, 1 pass 10-+6 mm, waiting time 10 seconds, 2 passes 6→3 mm, and when this was also plow rolled, it was rolled without any problem.

[Effects of the Invention] According to the present invention, it is possible to efficiently roll a polymeric material in a minimum amount of time, thereby producing effects such as being able to obtain a polymeric material having excellent properties.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the procedure for implementing the present invention.

Claims (1)

[Claims] 1. In a method of manufacturing a rolled plate made by stretching a polymeric material by rolling, the temperature of the material during rolling is estimated in advance based on the rolling conditions so that the rolled material is maintained at the desired temperature. , by changing any one or more of the line speed, rolling reduction rate, and waiting time between passes, rolling is performed in a plurality of passes in a minimum time while preventing melting of the rolled material. Rolling method.