JP3692155B2 - Bending method of polymer sheet - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for bending an unstretched polypropylene sheet such as a casting polypropylene sheet having excellent cold resistance, heat resistance and dimensional stability.
[0002]
[Prior art]
Conventionally, high-quality polymer shaped products were manufactured by the injection method in which the molten polymer was poured into a mold, by bender pressing, or by punching and simultaneous processing by the vendor, and long products were manufactured by extrusion or injection, etc. .
[0003]
[Problems to be solved by the invention]
However, according to the conventional method, since the production equipment is complicated and expensive, it has been impossible to produce a regular processed product of a high molecular weight polymer with simple equipment at low cost.
[0004]
[Means for Solving the Problems]
Therefore, the present inventor, as a result of intensive studies to eliminate the above-mentioned conventional inconvenience, changes in orientation by adding a stretching process in the bending direction to the unfolded polypropylene sheet, such as a casting polypropylene sheet, It was found that a long shaped processed product in which the portion becomes a constant bending reinforcement portion was obtained, and the present invention was completed.
That is, the polymer polymer sheet bending method of the present invention is a processing method of bending a long polymer polymer sheet into a predetermined shape, and is formed by a groove portion and a rotary blade having a blade edge immersed in the groove portion. The portion to be folded of a long unstretched polypropylene sheet having a thickness of 0.3 to 3.0 mm is continuously passed through the gap, and the portion to be folded is uniaxially stretched in the folding direction to be folded with orientation. It is characterized by being formed into a groove and being bent .
In addition, it is preferable that the said groove part is provided in the outer peripheral surface of a rotating roller along the rotation direction.
[0005]
A non-stretched polypropylene sheet such as a casting polypropylene sheet, which is a constituent material of the polymer polymer sheet, is formed into a uniform thickness without stretching a crystalline mixture having a propylene unit component of 50 mol% or more. Is obtained.
[0006]
The sheet has a thickness of 0.3 to 3.0 mm . This is because when the thickness is less than 0.3 mm, the sheet main body has no shape holding force, and when the thickness exceeds 3.0 mm, the line processing speed is reduced.
[0007]
[Action]
By forming the unfolded polypropylene sheet folds into fold grooves that are uniaxially stretched in the fold direction, the orientation of the folds changes, and a long shaped processed product is obtained in which the part becomes a constant bending reinforcement. It is done.
[0008]
【Example】
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a side view showing a processed state of an unstretched polypropylene sheet according to the present invention, FIG. 2 is a front view thereof, 1 in the figure shows a steel rotary blade, and a blade edge 1a is formed at 60 °. The tip of the blade edge 1a is rounded. In the figure, reference numeral 2 also denotes a steel rotating roller. On the outer peripheral surface 2a of the rotating roller 2, a substantially V-shaped annular groove 3 having a cross section of 90 ° is formed along the rotating direction. Yes.
[0009]
The blade edge 1a of the rotary blade 1 is disposed opposite to the annular groove 3 so as to be immersed therein. A gap 4 is formed between the blade edge 1a and the annular groove 3, and an unstretched polypropylene sheet is formed in the gap 4. Ten bent portions 11 were continuously supplied. The relationship between the feed speed of the unstretched polypropylene sheet 10 and the peripheral speeds of the rotary blade 1a and the rotary roller 2 at this time is 1: 1 because it is necessary to stretch only in the direction perpendicular to the traveling direction of the sheet 10. It was made to become the speed ratio.
[0010]
In this way, the planned bending portion 11 of the unstretched polypropylene sheet 10 guided into the gap 4 is pushed into the annular groove 3 of the rotating roller 2 by the cutting edge 1a of the rotary blade 1, and at this time, the planned bending portion 11 is sequentially turned on. While being stretched along this pushing direction, that is, the folding direction, it is bent at 90 °, and the bent portion is formed into a folded groove having orientation throughout the entire front and back.
Thus, an unstretched polypropylene sheet molded product 20 that is bent at 90 ° as shown in FIG. 3 is obtained. In addition, the arrow in FIG.3 (b) which is the B section enlarged view of Fig.3 (a) shows an orientation direction.
[0011]
In this embodiment, the non-stretched polypropylene sheet 10 is continuously stretched by so-called point pressure contact between the cutting edge 1a of the rotary blade 1 and the annular groove 3 of the rotary roller 2 by configuring the groove portion as the annular groove 3. Since the bending process is performed, the groove part subjected to the stretching process with extremely good directivity is continuously formed.
[0012]
In order to measure the strength of the bent portion having the orientation as described above, the strength was measured according to JIS K 7113. As a result, the strength was improved by 10% or more compared to the portion without bending, It was confirmed that the repeated bending did not break even 10,000 times or more and had excellent strength.
[0013]
The relationship between the size of the gap and the thickness of the polypropylene sheet is preferably such that the gap passes through 75% of the thickness of the sheet. That is, the sheet is preferably compressed to 25%.
[0014]
The angle between the groove and the blade edge depends on the desired bending angle. For example, in a 90 ° bent product, the groove is 90 ° and the blade edge is 60 °, which is about 3: 2. It is preferable to do this.
[0015]
【The invention's effect】
According to the present invention, a lightweight processed product having excellent dimensional stability and strength can be obtained using a polymer sheet as a material by a very simple method.
[Brief description of the drawings]
FIG. 1 is a side view showing a machining state according to the present invention. FIG. 2 is a front view showing a machining state according to the invention. FIG. 3 is an end view of a shaped product obtained by the machining method of the invention.
DESCRIPTION OF SYMBOLS 1 Rotating blade 1a Cutting edge 2 Rotating roller 2a Outer peripheral surface 3 Annular groove 4 Gap 10 Unstretched polymer sheet 11 Folding planned part 12 Folding groove 20 Molded product

Claims (2)

A processing method of bending a long polymer polymer sheet into a predetermined shape, and having a thickness of 0.3 to 3.0 mm in a gap formed by a groove portion and a rotary blade having a blade edge immersed in the groove portion The unfolded polypropylene sheet is continuously passed through a portion to be folded, and the portion to be folded is uniaxially stretched in a folding direction to form a fold groove having orientation , and is folded. A method of bending a polymer sheet.   2. The method for bending a polymer sheet according to claim 1, wherein the groove is provided on the outer peripheral surface of the rotating roller along the rotation direction.

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