JPS5842012B2 - Manufacturing method of synthetic resin band for heavy packaging - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method of manufacturing a synthetic resin band for heavy packaging.

Steel bands are known as binding bands for heavy-duty packaging, but they have the disadvantage that they rust when tying items left outdoors, making them dangerous to handle.

Therefore, a synthetic resin band without such drawbacks is desired, but since it is a band for heavy packaging, it is necessary to make the band thick.

Polyester, nylon, etc. are known as thick synthetic resin bands for heavy packaging.

A common disadvantage of polyester and nylon bands is that the raw materials are expensive.

Polyester bands have drawbacks such as poor stretchability, which makes them difficult to manufacture, and cannot be heat-welded, so they cannot be applied to automatic packaging machines.

Nylon bands stretch, making them unsuitable for heavy-duty packaging.

Therefore, polypropylene, which is a cheap raw material and easy to manufacture, has attracted attention.

However, thick bands made of polypropylene have the disadvantage of being easily broken.

If the band breaks, it may cause breakage.

Therefore, a breakable band is very dangerous when used for heavy packaging as it may cause secondary damage.

Therefore, the method of the present invention uses a raw material made of polypropylene mixed with a propylene-ethylene copolymer at a ratio of 1 to 3 (some fillers and pigments are also mixed), and a step of rolling simultaneously with stretching. Thus, we have provided a method for manufacturing a synthetic resin band for heavy packaging that is made strong and completely unbreakable by stretching and rolling the original fabric in a so-called multi-axis direction.

The method of the present invention will be explained in detail below based on examples shown in the drawings.

1:1 propylene-ethylene copolymer to polypropylene
Approximately 3 parts of a filler such as calcium carbonate and a small amount of pigment are added to the raw materials at a ratio of 1 to 3 parts, and the mixture is charged into a hopper 2 of an extruder 1.

The cylinder and mold 3 of the extruder 1 are heated to about 220° C. and extruded as a raw fabric 4.

The original fabric 4 extruded from the extruder 1 is introduced into a first water tank 5 directly below the mold and cooled once.

The cooled raw fabric 4 is sent from the first take-up roll 6 through the heating tank 7 to the rolling roll 8 while being stretched.

In the heating tank 7 , the original fabric 4 is preheated to 80° C. to 110° C. using hot water or the like, and then the original fabric 4 is rolled with a rolling roll 8 .

At this time, rolling is performed in the process direction and in a direction perpendicular thereto.

In the example shown here, the linear speed at the first take-up roll 6 is 8.0 m/min, and the linear speed at the rolling roll 8 is 18.0 m/min.
Although it is set to 0 m/min, this linear speed difference is due to the fact that the original fabric 4 is stretched in the process direction and rolled at the same time.

The original fabric 4 stretched and rolled here will be referred to as a band 10 hereinafter.

Rolling is carried out at a roll temperature of 80° C. to 90° C. in the rolling rolls 8. In this example, where the thickness of the original fabric 4 is 3.0 mm, rolling is performed with a rolling roll gap of 0.58 mm.

The strip 10 rolled by the rolling roll 8 is transferred to the second take-up roll 9
The line speed at this take-up roll 9 is set to 65.0.
m/min.

Since the linear speed of the roll 8 described above is 18.0 m/min, the stretching ratio between the roll 8 and the second take-up roll 9 is 3 times or more.

That is, stretching is carried out at the same time as rolling, and in order to finally obtain a band with no vertical cracks, the deformation rate is 2 to 5.
The range shall be .

Here, the deformation rate refers to the ratio of the width of the product divided by the thickness of the product and the width of the original fabric 40 divided by the thickness of the original fabric 4.

In the example shown here, the original fabric dimensions are 22.0 mm in width and 3.0 mm in thickness, while the product dimensions are 15.8 mm in width and 0.66 mm in thickness, and the deformation rate is 3.26.

The strip 10 taken off by the second take-up roll 9 is sent to an embossing roll 11, where it is further embossed to prevent vertical cracking.

The embossed strip 10 is then introduced into an annealing tank 12 and annealed with steam at 90° C. to 1100° C., cooled in a second water tank 13, and wound onto a winding drum 14.

Extrusion is carried out continuously in this winding case, starting with extrusion using the extruder 1.

The above-described stretching, rolling, and annealing temperatures are appropriately set depending on the thickness, width, etc. of the original fabric.

Further, the stretching ratio and the rolling roll gap are also adjusted to correspond to the thickness, width, etc. of the original fabric.

A stretching tank may also be provided between the rolling roll 8 and the second take-up roll 9 to heat the film at an appropriate temperature, and the next embossing process can be carried out as required.

The compounding ratio and molding conditions of the manufacturing method of the present invention, which is one example described above, will be shown in specific detail.

Blending ratio Polypropylene 1 + propylene-ethylene copolymer 2 Raw material filler 3.2 Multi-pigment Some molding conditions Extruder Cylinder diameter 65ψ Slit size 37mmX4mm Cylinder temperature conditions Cylinder 1210°C Cylinder 22158C Cylinder 3 240'C Mold 210° C Mold tip 215℃ First water tank Mold-water surface air gap 50mm Water temperature
20'C First take-up roll linear speed 8.0 m/min Original fabric preheating temperature Hot water 98°C Rolling roll linear speed 18. Om/min 2nd take-up roll linear speed
65.0m/min annealing temperature
Steam 1048C third take-up roll linear speed 5
5.0m/min Original fabric size 22.0mm
X 3.0mm Product dimensions 15.8mm
Xo, 66mm Deformation rate: 3,26 Rolling roll temperature: 85°C Rolling roll gap: 0.58mm Next, a band produced by the production method of the present invention as described above, a band produced by a normal stretch-molding method without rolling polypropylene, and The physical properties will be compared with a band made of polypropylene by the above manufacturing method of the present invention.

Note 1) The above sample sample band has a width of 16 mIn and a thickness of 0.8 nm.

Note 2) Vertical cracking ■ is the number of cracks at the edge (right angle) of the band when it is pulled and broken.

Average value of measurement number n = 5. When a raw material made of polypropylene mixed with a propylene-ethylene copolymer is made into a band by a normal stretch-molding method, the longitudinal crackability is only slightly difficult to crack.

1:1 propylene-ethylene copolymer to polypropylene
The synergistic effect of blending 1 to 3, blending a large amount of the polypropylene-ethylene copolymer, and rolling simultaneously with stretching produces a remarkable flat-splitting effect on longitudinal cracking properties.

First, by blending a large amount of copolymer, some molecules are joined in the horizontal direction even when stretched, and the molecular orientation is disturbed in the vertical and horizontal directions by rolling, producing a band that is resistant to vertical cracking. be able to.

If the ratio of propylene-ethylene copolymer to polypropylene is less than 1:1, the band will easily break, making it unsuitable as a band for heavy-duty packaging.

If the ratio of the propylene-ethylene copolymer to the polypropylene in the residue exceeds 1:3, the tensile strength will decrease, making the band unsuitable as a heavy-duty packaging band.

The synthetic resin band manufactured by the method for manufacturing a synthetic resin band for heavy duty packaging of the present invention as described above does not suffer from any vertical cracking, has low elongation at break, and has high toughness because it contains ethylene.

Therefore, it is an excellent synthetic resin binding band for heavy-duty packaging and is inexpensive.

Binding bands for heavy packaging are particularly at risk of cracking.

If a crack occurs in a part of the band, this part will cause the band to break, which is very dangerous.

Therefore, for heavy-duty packaging, it is necessary to sufficiently connect the molecules by multiaxial stretching and rolling to form a band that does not cause any cracks.

In addition, since it has excellent thermal weldability, we were able to manufacture a synthetic resin band for heavy packaging that is suitable for automatic packaging machines.

Furthermore, this method allows for the simple and easy production of excellent synthetic resin bands for heavy duty packaging by simply installing a rolling device in conventional production equipment.

[Brief explanation of drawings]

The drawings are schematic diagrams showing the manufacturing process of the method of the present invention. DESCRIPTION OF SYMBOLS 1... Extruder, 4... Original fabric, 6... First take-up roll, 7... Heating tank, 8... Rolling roll, 9... Second take-up roll, 10... Band body, 11... Emboss roll.

Claims (1)

[Claims] 1 Using a raw material made of polypropylene mixed with a propylene-ethylene copolymer at a ratio of 1:1 to 3, the original fabric is extruded from an extruder and cooled once, then passed through a first take-up roll and heated in a heating tank. Preheat it, then feed it while stretching it to a rolling roll that has been heated to an appropriate rolling temperature, and at the same time as rolling, take it up to a second take-up roll to stretch it, and finally make the deformation ratio in the range of 2 to 5. A method for manufacturing a synthetic resin band for heavy packaging, characterized by: