JP2875337B2 - Removal of tubular film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention forms a pair of take-off pinch rollers by gradually folding a tubular film discharged from a die and blown to a predetermined diameter into a flat shape. The present invention relates to a method of taking a tubular film to be taken while being guided toward the same.

[Conventional technology]

Generally, a tubular film is melted while being transported by a screw conveyor in a sealed cylinder of a resin such as a thermoplastic resin fed from a hopper by an extruder, and then the molten resin is directed toward a die having a predetermined shape. It is formed by extruding, discharging the molten resin into a tubular shape from the discharge port of the die, and blowing the molten resin into a desired tubular film shape.

FIG. 8 shows such a conventional resin molding apparatus, in which a resin 3 introduced from a hopper 2 provided on an upper surface of an extruder 1 is turned by a screw conveyor 4 into a cylinder 5 toward a head 6. Heater (not shown) while being transported
And then extruded from the extrusion port of the head 6,
Subsequently, it is sent to the inlet 9 of the die 8 via the feed pipe 7. Then, the molten resin 3 is formed into a cylindrical shape by the die 8 and discharged upward from the discharge port 10, and air is fed into the die 8 from the air supply port 11 and a predetermined pressure is supplied from the air ejection port 12. Then, air is blown into a cylindrical film made of the molten resin 3 to blow up the resin 3. The discharged resin 3 is cooled by cooling air jetted from a cooling air supply device 13 and is a tubular film having a predetermined diameter.
It is assumed to be 14. The tubular film 14 is guided toward the pair of pinch rollers 16, 16 by being gradually folded in a plane by the pair of guide plates 15, 15, and at a predetermined take-up speed by the pinch rollers 16, 16. , And then wound up by the winding roller 17 on the downstream side.

These guide plates 15, 15 are arranged such that the intersection of the extension lines extending upward from the surfaces 15 a, 15 a facing the tubular film 14 is a contact point on the outer peripheral surface of the pinch rollers 16,
Is provided so as to coincide with the pick-up location.

[Problems to be solved by the invention]

However, in the conventional guide plate 15, the surfaces 15a, 15a facing the tubular film 14 are formed in a flat shape, so that the tubular film 14 taken by the pinch rollers 16, 16 is in the width direction when folded. There is a disadvantage that a slack is formed in the center portion and a slack is formed in both edge portions in the width direction.

 The cause will be explained theoretically.

9 and 10 show two planar guide plates 15,15.
Shows a three-dimensional geometric trajectory when the cylindrical tubular film 14 is forcibly deformed into a planar shape, and is taken up at high speed by a pair of pinch rollers 16 and 16 and is forcibly cooled at high speed. Tubular film 14
Assumes that the working portion of the guide plate 15 is already hardened, and furthermore, the radius of the tubular film 14 is R, and the tubular film 14 rises at a constant speed and is guided from the portion of the level ab. It is assumed that a pair of pinch rollers 16, 16, which are forcibly squeezed by the plate 15 and are folded flat by a pair of pinch rollers 16, 16 with a diameter B at the level cd. In this case, the surface narrowed by the guide plate 15 has a substantially parabolic shape as shown in FIG. Both levels ab and c of the center line OO of the paraboloid
Let L be the length between -d. The length between the widthwise end of the level cd portion of the tubular film 14 folded in a planar shape and the widthwise end of the level ab portion is S.

Under these solid geometric conditions, Becomes

 From equations (2) and (3), L> S (4).

According to the formula (4), the tubular film 14 that is taken by the pair of pinch rollers 16 and 16 is taken in a state where pins are stretched at both ends in the width direction, and sags by L-S at the center in the width direction. It is understood that the slackness and the ear slack occur.

Further, when the theoretical analysis is performed, L ² −S ² is obtained from Expressions (2) and (3), and R is obtained by substituting R obtained from Expression (1) to obtain L ² −S ² = 0.067B ² ... (5)

Here, for example, when S is obtained by substituting L = 1.5B into equation (5), S = 1.4775B (6)

 Therefore, L−S = 1.5B−1.4775B = 0.0225B (7)

From the equation (7), the difference between L and S is about 2% of the diameter B. For example, when a tubular film 14 of B = 2000 mm is manufactured, L−S ≒ 40 mm, and the width direction center portion Is 40mm or more longer than both ends in the width direction. In addition, since the conventional guide plate 15 has a flat surface 15a facing the tubular film 14, the pinch roller 16 can be used without removing slack at the center in the width direction.
As a result, the pinch roller 16 picks up the slack with the slack in the middle and the slack in the ear.

The tubular film 14 having such a slackness and a slack in the ear has uneven thickness, and cannot be a raw material of a paper-like film which is obscured today with a large uneven thickness.
Further, when used as a laminate film, there is a problem that the laminate may be laminated in a state where air enters the uneven thickness portion.

The present invention has been made in view of these points, and absorbs the slack that theoretically occurs, guides the tubular film so that the tubular film can be taken off by the pinch roller without slack, and listens for the slack. It is possible to produce extremely high-quality films with no slack, no uneven thickness and no scratches.
An object of the present invention is to provide a method of taking a tubular film which enables high-speed production, has a simple structure and is inexpensive.

[Means for solving the problem]

In order to achieve the above object, according to claim 1, the method for taking a tubular film of the present invention comprises the steps of: discharging a tubular film discharged from a die and blown to a predetermined diameter;
A method for taking up a tubular film, wherein the tubular film is taken up by the pair of pinch rollers while being guided by the pair of tubular film taking stabilizers so as to be gradually folded in a plane toward the pair of take-up pinch rollers, From the gas blowing portion formed on the surface of the tubular film taking-up stabilizer facing the tubular film, the tubular film is taken out while blowing gas toward the tubular film to deform the tubular film inward. Features.

(Operation)

According to the tubular film of the present invention, by blowing gas from the gas blowing portion toward the tubular film, the tubular film is deformed so as to be recessed inward, and the slack that theoretically occurs is deformed by this inward deformation. Absorbs so that it is in a state without slack when it is taken up by the pinch roller, and it is possible to produce a high-quality film with a uniform thickness without slack and without slack. .

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

FIGS. 1 to 4 show an embodiment of the tubular film taking-up stabilizer of the present invention, and FIGS. 5 to 7 show a state of guiding the tubular film according to the embodiment of the present invention. The same reference numerals are given to the same parts as.

As shown in FIGS. 1 to 4, the guide plate 21 of the present embodiment has a surface 21a facing the tubular film 14 having a width dimension and a longitudinal dimension larger than the B × L dimension of the tubular film 14 to be produced. A bleached cotton 22 as one type of an adhesion preventing member is adhered to the surface of the facing surface 21a. This opposite surface 21a has a bleached cotton 2
A large number of air blowing holes 23, 23,... Serving as gas blowing sections for blowing air as gas toward the tubular film 14 are also formed so as to penetrate the tubular film 14. The area where these air blowout holes 23, 23 are formed is inside the paraboloid shown by the broken line in FIG. 1 where the tubular film 14 is guided along the facing surface 21a of the guide plate 21, and The opening area of the air blowing holes 23 per unit area is adjusted according to the amount of bulging of the film 14 into the inside. In the present embodiment, since the size of each air blowout hole 23 is made equal, the air blowout hole 23 of each air blowout hole 23 is formed closer to the lower part of the paraboloid where large inward deformation of the tubular film 14 is required. The installation pitch has been reduced. The adjustment of the opening area of the air blowing holes 23 may be performed by changing the diameter of each air blowing hole 23 by making the drilling pitch of the air blowing holes 23 equal, and changing both the drilling pitch and the diameter of the holes. You may make it. An air intake tube 24 for supplying air to the inside is fixed to the back of the hollow box-shaped guide plate 21, and the guide plate 21 is attached to the upper and lower sides of both sides under the pinch roller 16. Are provided for suspension at the position.

A pair of guide plates 2 of the present embodiment thus formed
As shown in FIG. 5, 1,21 is such that the intersection of the extension line above the facing surface 21a coincides with the contact point of the pair of pinch rollers 16,16, and satisfies the set L. And the position of the fixing rod 27 penetrating through the hole 26 of each of the suspension stays 25, 25 is adjusted. Also,
Blowers 28 installed to supply air into each guide plate 21
The supplied air is divided into two parts by a branch tank 29, and the air is supplied to the air intake cylinder 24 through the air flow paths 30 each having a flow control valve 31.

Next, the operation of the present embodiment will be described based on the method of the present invention.

In the resin molding apparatus in which the pair of guide plates 21 and 21 of this embodiment are installed, the resin 3 is discharged from the discharge port 10 of the die 8 into a cylindrical shape using the extruder 1 in the same manner as in the conventional case. Air is blown out from the air outlet 12 to blow up the resin 3 and the resin 3 is forcibly cooled by the cooling air supply device 13 to form a tubular film 14 having a predetermined diameter.

At the same time, the air generated by the blower 28 is guided to the respective guide plates 21 and 21 of the present embodiment through the air flow path 30 and the air intake cylinder 24 while adjusting the flow rate to be appropriate by the respective flow control valves 31. It is fed into the plate 21. This guide board 21
Air is blown out at a predetermined pressure toward the tubular film 14 from the air blowing holes 23 formed in the facing surface 21a and the bleached cotton 22, and the tubular film 14 is blown as shown in FIGS. 5 and 7. The parabolic surface is deformed so as to be recessed inward. Due to the recess into the inside of the tubular film 14, a slack in the central portion in the width direction of the tubular film 14 corresponding to L-S theoretically generated is absorbed,
The take-up speed of the tubular film 14 at the time of being picked up by the pair of pinch rollers 16 and 16 becomes constant in the axial direction of the pinch roller 16, and the film is picked up without slack or slack.

Further, since the bleached cotton 22 is adhered to the opposing surface 21a of the guide plate 21, even if the tubular film 14 may come into contact with the opposing surface 21a, the bleached cotton 22 remains on the opposing surface of the tubular film 14. While effectively preventing adhesion to 21a,
Since the bleached cotton 22 is a material that does not easily damage the tubular film 14, the tubular film 14 is not damaged at all.

Therefore, the tubular film 14 manufactured using the guide plates 21 and 21 of the present embodiment has no slack and no slack, and has no scratches, and is of extremely high quality without uneven thickness. Becomes Therefore, it can be used as a raw material for a paper-like film that is in the spotlight today, and has extremely high commercial value.

In addition, the tubular film 14 basically has the facing surface 21a.
And pinch rollers 16, 16 without contact with bleached cotton 22
As a result, the resistance to the take-up of the tubular film 14 is extremely small as compared with the conventional example, so that the take-up is easy and the labor can be saved. Further, the air blown from each air blowing hole 23 toward the tubular film 14 improves the cooling efficiency of the tubular film 14, so that a higher quality tubular film 14 can be obtained, and eventually the productivity of the tubular film 14 can be improved. Improvement is achieved.

In addition, since the tubular film 14 is recessed inward, two films of the tubular film 14 that are about to be folded in a plane just before the pair of pinch rollers 16 and 16 are conventional examples. Since the state is almost vertical as compared with the above, the occurrence of slackness is further prevented.

In the embodiment, the opposing surface 21a of the guide plate 21 is used.
Although the bleached cotton 22 is adhered to the airbag, the bleached cotton 22 can be omitted when the pressure of the air blown out from the air blowing holes 23 is large and the tubular film 14 does not touch the facing surface 21a. Further, the air blowing method on the opposing surface 21a of the guide plate 21 may be modified as necessary, for example, by using a mesh or providing a large number of blowing nozzles instead of the air blowing holes 23 in the above-described embodiment.

Further, the present invention is not limited to the above embodiment, and can be modified as needed.

〔The invention's effect〕

As described above, since the tubular film taking-off method of the present invention is constituted and operates, the tubular film is absorbed so that the tubular film can be taken off by the pinch roller in a state where there is no slack, which theoretically occurs. Guides can produce extremely high-quality films with no slack and ear slack, without uneven thickness and without scratches, enabling low-cost and high-speed production of films, with a simple structure and low cost. And so on.

[Brief description of the drawings]

1 to 7 show an embodiment of a stabilizer for taking up a tubular film of the present invention, FIG. 1 is a front view, FIG. 2 is a cross-sectional view taken along the line II-II of FIG. Fig. 3 is II in Fig. 1.
FIG. 4 is an enlarged view of a part IV in FIG. 2, FIG. 5 is a sectional view of a main part showing a state of guiding the tubular film according to the present embodiment, and FIG. 5 right side view,
7 is a sectional view taken along the line VII-VII of FIG. 6, FIG. 8 is a schematic view of a conventional resin molding apparatus using a guide plate, and FIG. 9 shows a deformed state of a conventional tubular film. FIGS. 10 (a) and 10 (b) are a front view and a right side view, respectively, showing a deformed state of the tubular film. 1 ... extruder, 3 ... resin, 8 ... die, 21 ... guide plate, 21 ... facing surface, 22 ... bleached cotton, 23 ... air blowing hole.

──────────────────────────────────────────────────の Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B29C 55/28

Claims (1)

(57) [Claims] 1. A tubular film discharged from a die and blown to a predetermined diameter is gradually folded by a pair of stabilizers for taking up a tubular film toward a pair of pinch rollers for taking up. In the method of taking a tubular film to be taken up by the pair of pinch rollers while guiding as described above, the tubular film taking-up stabilizer is attached to the tubular film by a gas blowing portion formed on a surface facing the tubular film. Blowing gas toward, deformed so that the widthwise intermediate portion of the tubular film take-up stabilizer is recessed inward,
Absorb theoretically generated slack by this inward deformation, and take off the tubular film while deforming the tubular film inward so that it is in a state without slack when it is taken by the pinch roller. A method for collecting tubular film, comprising: