JP5937374B2 - Production apparatus and production method for thermoplastic resin film - Google Patents

Description

  The present invention relates to a method for producing a film at low cost by efficiently reusing a thermoplastic resin film, and a production apparatus for carrying out the method.

  The thermoplastic resin film has an ear that does not become a product in the film forming process. In addition, slitting is generally performed in order to obtain a product having a predetermined width from a wide intermediate product. Even at this stage, a portion remaining on the core of the cut and wide intermediate product appears. In addition to this, the appearance of windings such as `` wrinkles '', `` uneven end faces '', `` gauge bands '', etc. generated in the slits, `` scratches '', `` dirt '', `` Defects such as “open holes” and parts that do not become products occur due to changes in product type. These may be reused in the following way.

  That is, when the film is finely pulverized or compressed, and then melted with an extruder or the like to obtain a strand, solidified (referred to as a recycled chip), and the same or similar thermoplastic resin film is produced again. It is put together with a new unused thermoplastic resin (hereinafter referred to as virgin raw material or virgin chip) and melted in an extruder to obtain a predetermined thermoplastic resin film.

  In order to advantageously perform this reuse, for example, Japanese Patent No. 3601729 discloses a manufacturing apparatus and method thereof. In this document, the problem that the influence of the filler already added remains, and as a countermeasure, a detailed structure is proposed for the polymer filter in the manufacturing apparatus.

However, a new problem has recently occurred as a problem in reuse. That is, a thermoplastic film is often provided with a coating such as easy adhesion, easy slipping, peeling and antistatic so as to be suitable for processing by a customer. Even if the coating passes through the pulverization or melt extrusion in the reuse process, the coating components are not sufficiently pulverized or dispersed, and sometimes the gelation inherent to the resin is promoted. On the other hand, in order to produce a thermoplastic resin film at a low cost, the ratio of recycled materials is increased. Then, as a result, gel-like foreign matters are generated due to these, and the quality cannot be maintained. It's a number no problem in the initial production to increase over time, there is that frequently no longer have to Re cry conducted a filter replacement. Some devices change filters in a very short period of time without stopping film formation, but in any case, the product does not become a product during that period, resulting in loss.

  JP-A-2004-169005 proposes cleaning with a solvent to remove the coating provided on the film, which causes frequent filter replacement. In the case of the solvent treatment, there is a problem that the subsequent treatment is complicated and the running cost increases. Japanese Patent Application Laid-Open No. 2002-301720 proposes a number of methods for expanding the application to resin base materials and removing the coating film with physical force. Among these proposals, the proposal of using an abrasive having a diameter of 0.1 to 100 mm is an important issue for the sufficient recovery of the abrasive to prevent contamination of the raw material, and its countermeasure is extremely difficult. A method of coarsely pulverizing a processed product and stirring it together with an abrasive has also been proposed, but has the same problems as described above. In addition, there is a proposal to remove by brush rubbing, but when removing the coating, it is necessary to consider the material of the brush used, the thickness of the coating, etc., but it remains an abstract proposal. As it is, it does not obtain a sufficient effect. In JP-A-10-128746, although it is for a thick resin plate, it is peeled by generating a shearing force by rolling. This method cannot be applied to a resin film having a thin base material thickness and thin film.

Japanese Patent No. 3601729 JP 2004-169005 A JP 2002-301720 A JP-A-10-128746

  An object of the present invention is to provide an apparatus and a method for advantageously reusing a waste film generated in the process of manufacturing a thermoplastic resin film. In particular, even a scrap film having a film with a specific function added can provide a method for efficiently removing the film, thereby reducing the production cost by reducing the ratio of the virgin raw material used during film production. An apparatus for manufacturing a thermoplastic resin film and a method for manufacturing the same are provided.

The object of the present invention is achieved by the following manufacturing apparatus and manufacturing method. That is, the present invention
(1) While running a film provided with a coating on at least one side of a melt-extruded base film, a rotating brush having metal fiber bristles is brought into contact with the coating to remove the coating, the embracing angle of the rotating brush and the substrate film and at least 20 °, and the method of removing the film surface coating, characterized in that the surface speed of the rotary brush 10 to 300 times the speed of the full Irumu,
(2) A method for producing a thermoplastic resin film, comprising collecting and reusing the film after removing the film by the method described in (1), and
(3) A traveling device for traveling a film having a coating on at least one side of the base film and a rotating brush having metal fiber bristles are provided, and the rotating brush contacts the coating on the traveling film. The film surface film removing apparatus is characterized by removing the film by setting the surface speed of the rotating brush to 10 to 300 times the traveling speed of the film.

At this time, since the removed coating is powdery, it is removed by suction with a nozzle. It should be avoided as much as possible that this powder gets on the film and is mixed in the pulverization and regeneration process of the next process. Moreover, since the powder fills the gaps between the fibers of the brush, it must be sucked from the brush.
The brush should be made of metal since resin hair is insufficient in removing the film. Of these, stainless steel is desirable because it has sufficient toughness and is rustproof. If the toughness of the hair is too low, it will not penetrate into the coating and the coating cannot be removed sufficiently. On the other hand, if the toughness is too high, the substrate under the coating may be significantly damaged and its breakage may be caused. Undesirably the traveling film being processed to break causes the problem of worker load increase of the drop and re-throw Irisaku industry inhibit continuous processing capacity.

Rotational speed of the brush also for efficient processing without being to put the break, may be set the surface speed of the brush 10 to 300 times the speed of the full Irumu. In continuous operation, it is desirable that the rotational speed of the brush be accelerated / decelerated in conjunction with the running speed of the film and automatically adjusted to fall within this range.
The film from which the coating has been removed may be reused by being mixed with a virgin chip in a melt extruder for producing a product as it is. However, in order to reduce the variation in product quality and adjust the life of the polymer filter installed downstream of the melt extruder, the product is once recycled into a recycle-only melt extruder, which is then used as a product extruder. It is better to mix with virgin chips.

The target film is not particularly limited, but in the case of a material that usually attacks the base film with a solvent, or when it is thin relative to the thickness of the base film and you want to suppress damage to the base film The effect is fully manifested. In many cases, recycled chips are already reused at a low ratio. In particular, it is extremely effective for removing a silicone-based film having high slipperiness. An acrylic easy-adhesion coating is also effective.
Although the base film is not particularly limited, it is a particularly useful method for a polyester film that promotes the generation of a gel, for example, by the impurities in the molten resin being a nucleus.

The coatings removal device by using the weight ratio of recycled chips can suppress foreign matter as 30% to 100%, it is possible to produce lower the cost of the same type of product.

It is a flowchart of the thermoplastic resin film manufacturing apparatus which concerns on one embodiment of this invention. It is explanatory drawing which shows one embodiment of this invention. It is explanatory drawing which shows one embodiment of this invention. It is explanatory drawing which shows one embodiment of this invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a flowchart for explaining one embodiment of the thermoplastic resin film production apparatus of the present invention. This is an example of a biaxially stretched film, but the present invention is effective for both uniaxially stretched and unstretched films.

In general, several kinds of resin pellets (chips) are weighed and mixed in one weighing process, and the thermoplastic resin film is crystallized and dried as needed in the second drying process, and is put into the third extruder. Then, the sheet is extruded through a slit die, passed through a cooling drum, and then longitudinally stretched by a uniaxial stretching machine. Then, before then passing through a biaxial stretching machine 9, sometimes making the films in the coating apparatus 8. Alternatively, in the case where stretching is performed simultaneously with a biaxial stretching machine, coating may be performed before that. In either case, the effect of the present invention is not changed. After biaxial stretching, the ear 11 is cut off in 10 transport steps, and a mill roll 13 as an intermediate product is obtained with a winder 12. Mill roll is slit into a predetermined width 14 of the slitting step, it is delivered to the customer through the higher packing factory 15. In the slitting process, 16 cuttings that are ears generated for cutting out to a predetermined width and a core part 17 of a mill roll remaining after feeding a predetermined length are generated as a scrap film. 11 ear edge films, 16 cuts, 17 core films are 1
It is pulverized in the pulverizing step 8, stored and dried as necessary, extruded as a strand by the regenerative extruder 20, and cut to obtain recycled pellets (chips). This pellet is again transported to one weighing step. The coating width of the coating No. 8 can be determined so as to be convenient after biaxial stretching. However uncoated portion and the coating portion in sliding property is different when 10 winder transport steps and 12, 14 of the slitting step, since often be to put the problems such as wrinkles, is substantially intermediate products mill roll width Adjusted. Thus, typically the core film 16 of Court overlooked 17 is introduced into the regeneration step while holding the film.

In the regeneration process of the present invention, the film peeling apparatus of the embodiment shown in FIGS. The coated base film 70 to be regenerated is guided by a guide roll 72 and contacts the rotating brush 74 while holding a holding angle of 20 ° or more.
The guide roll 72 is usually made of stainless steel or has a hard chrome plated surface. The driving of the guide roll 72 is not essential. However, in order to stabilize the film tension in contact with the brush, it is desirable to install nip rolls 73 at the front and rear as shown in FIG. 3, or to adopt a nip system that drives the guide roll 72 as shown in FIG.

The coating to be treated is present on the surface on the rotating brush 74 side. If the rotating brush 74 is securely fixed so that the hair (stainless steel wire) does not come out by being pressed against the centrifugal force at high speed rotation or the film, the fixing method is not particularly specified. For high-speed rotation, rolls with metal wires embedded in channels or rings are wound around a roll core that is balanced in motion with iron, stainless steel, aluminum, CFRP, etc., or holes are formed at regular intervals along the circumference. After the discs with the bristles fixed on the core are passed through the core, the outer diameter is cut and the hairs are aligned while rotating the brush. One way to make it.
The material of the brush bristles is made of iron, brass or stainless steel, but rust prevention is required for the regeneration process and toughness is also required for removing the coating, so stainless steel is better. It is better to raise the basis weight as much as possible.

This brush is rotated at high speed by an electric motor. The driving method is not particularly limited, but the surface speed needs to be 10 to 300 times the speed of the film 70 to be processed. The film speed in the reproduction process is usually about several m / min to about 100 m / min, but the actual outer diameter of the brush 74 is practically about φ400, so it exceeds 2400 rpm. Therefore, the speed of the motor is increased using a pulley or the like. Also, in order to rotate the brush within the optimum range, it should be possible to configure the speed continuously with an inverter or the like. Desirably, it is a system that always automatically adjusts at a speed set to the speed of the film 70. A more desirable speed ratio is 30 to 200. Is not particularly limited rotational direction of the brush 74, even wind for high speed rotation occurs, since waste powder removed coating is undesirable sent downstream leading to mill the running direction of the film The opposite direction 77 is preferable. Since the powder is difficult to remove when charged, the brush 74 should be grounded well and the film 70 should be appropriately neutralized.

A film is wound around this brush so that the holding angle 75 is 20 ° or more, and preferably 40 ° or more, and a tension is applied and pressed. In order to obtain sufficient removal of the film without breaking the film, it is necessary to adjust the tension.
In order to control the holding angle, guide rolls 72 are provided before and after the rotating brush 74, but a near roll with the guide rolls 72 as close as possible as shown in FIG. For stable tension control, it is ideal to use the nip roll 73 before and after as shown in FIG. 4, but a sufficient effect can be obtained even if the nip roll 73 is placed separately as shown in FIG.

  The dust is first removed by suction. Suction is performed from the suction port 79 around the brush, or the nozzle 80 is separately installed for suction. Suction air separates the powder with a cyclone or filter. Needless to say, for continuous operation of the apparatus, there is a device such as switching the filters in parallel or using a roll type.

The chips thus pulverized, melt-extruded and recycled in the regeneration process are mixed with virgin chips and put into the extruder 3. The extruder 3 may be biaxial or uniaxial, and the presence or absence of a vent is not particularly limited. However, since a tendency to break the gel shape is recognized with a high share, and as a result, the filter life may be increased, the twin screw extruder is preferable.
The filter of 4 may be either leaf type or candle type. The arrangement of the elements may be either vertical or horizontal, but the vertical type is preferred as is generally said.

  The filtration accuracy of the filtration layer for molten resin is set based on quality requirements. Although 1/5 or less of the size of the foreign particle nucleus is a standard, it is in the range of 0.6 to 15 μm with 95% collection efficiency. Many thermoplastic resin films are often required to suppress the number of foreign matters of 50 μm or more.

  As the thermoplastic resin used in the present invention, polyethylene terephthalate, polyethylene 2,6-naphthalate, polyphenylene sulfide, polypropylene, polystyrene, which are thermoplastic resins having high functionality in mechanical properties, thermal properties, electrical properties, etc. Polyamide, aramid, etc. are preferred. In particular, thermoplastic resin is melt-extruded into a sheet, biaxially stretched in the longitudinal and lateral directions, and heat-treated for photoresists, magnetic materials, surface protection, and reflection, with excellent dimensional stability, mechanical and thermal stability Suitable for thermoplastic resin films used for optical applications such as prevention.

  Hereinafter, the present invention will be described in more detail with reference to examples. The measurement method was as follows.

(1) Average particle diameter of filler The area of a particle is obtained from a transmission electron micrograph, and the average value is obtained from all observed particles as the diameter of a circle having the same area.

(2) Filtration accuracy 11 types of test powder JIS-Z8901-1974 or dust ACFTD was dispersed in distilled water, the particle size distribution was measured with HIAC, and 95% compared with the particle size distribution after passing through the filter. Use the cut value as the filtration accuracy.

(3) Number of foreign matter in film The polyester film was cut into 210 mm length × 148 mm width (area 310.8 cm ² ), and the entire range of this film was subjected to foreign matter inspection by visual inspection by the crossed Nicols method. Subsequently, the foreign matter in the detected sample film was observed with transmitted light using an optical microscope, and the maximum diameter of the portion observed as an optically abnormal range was defined as the size of the foreign matter. In addition, when the cavity (void) which exists around a foreign material nucleus is observed as an optically abnormal range, it included in the size of the foreign material. And the magnitude | size of the foreign material particle was measured by the average diameter, and it divided into the rank of 50 micrometers or more and less than 90 micrometers, and 90 micrometers or more, and counted the number.

(4) Intrinsic viscosity Intrinsic viscosity ([η] dl / g) was measured with an o-chlorophenol solution at 25 ° C.

(5) Melt density The PVT measurement of the thermoplastic resin heated and melted was performed, and the value under the pressure of the filter part was taken as the melt density.

(6) Amount of filtration For equipment with gear pumps, the number of revolutions is measured with the resin discharged from the slit die outlet for the number of revolutions for equipment with no gear pump, and for the speed of extruders for equipment with no gear pump. Accumulated from the relational expression of number-discharge amount was used as the filter filtration amount.

Examples 1-5
Using a rotating brush having stainless steel bristles and having an outer diameter of 180 mm, the coating was removed using the apparatus shown in FIG. 3 while changing the film speed and the number of rotations of the brush. The near roll 72 has a diameter of 100 mm and is made of hard chrome plating and arranged as shown in FIG.
The holding angle was adjusted by adjusting the positions of the guide roll 72 and the rotating brush 74. The processing width is about 1000 mm.
As shown in FIGS. 2 and 3, the powder is sucked in such a manner that a suction nozzle 80 is installed at a position of several mm from the brush surface and the suction port 79 has a sufficient wind speed from the chamber 71.
The recycled chip is obtained by pulverizing a film subjected to film removal treatment with a pulverizer, extruding it into a strand shape through a filter having a filtration accuracy of about 20 μm with a normal single-screw extruder, and cutting and pelletizing the film.
As the filter device, a common device was used in which leaf filters were stacked and the filter shaft was stacked and assembled using the support as a support and contained in the filter housing.

The obtained thermoplastic resin recycled chips and virgin chips are mixed, after passing through the filter, it is passed through until the pressure at the inlet of the filter is 25MP a as the upper limit, using a wide mouth, the cooling drum Was discharged. The surface temperature of the cooling drum was 20 ° C. In addition, electrostatic pinning was used to bring the thermoplastic resin sheet into close contact with the drum. The filter for film formation here was a non-woven filter having a filtration accuracy of about 8 μm and an outer diameter of about 12 inches.
The biaxially stretched polyester film is obtained by stretching this unstretched film at Tg to (Tg + 60) ° C. so that the total magnification becomes 3 to 6 times once or twice in the longitudinal direction, and then Tg to (Tg + 60) ° C. Then, the film is stretched so that the magnification is 3 to 5 times in the width direction, and component A is applied on both sides thereof, or component B is applied uniformly on one side with a roll coater.
Alternatively, the film is stretched simultaneously in the longitudinal direction and the width direction, further subjected to heat treatment at 180 to 230 ° C. for 1 to 60 seconds as necessary, and contracted by 0 to 20% in the width direction at a temperature 10 to 20 ° C. lower than the heat treatment temperature. It is obtained by performing reheat treatment while Tg was 78 ° C. in terms of glass transition temperature. Intrinsic viscosity was 0.64 dl / g.

Here, after extending | stretching to the vertical direction, the coating films A and B were apply | coated uniformly with the roll coater on both surfaces. Subsequently, it was supplied to a tenter and proceeded to winding and slitting processes after transverse stretching and heat setting treatment. Foreign matter was inspected with a film sampled from the product after the slit. The results are shown in Table 1.
The operating condition “◯” in the film removal apparatus indicates that the film removal process was continuously continued without cutting the film in the process. In the determination of the film forming condition, the foreign matter was 50 to 90 μm in size, less than 50, and 90 μm or more and less than 10 was evaluated as “good”.

<Film of coating A>
The polyethylene terephthalate chip was dried at 170 ° C. for 3 hours, then supplied to an extruder, melted at a melting temperature of 295 ° C., filtered through a filter device 80, stretched 3.6 times, and rapidly cooled to obtain a longitudinally stretched film. . The ratio of recycled chips was 30%.
An aqueous coating liquid having a solid content concentration of 8% was applied to both surfaces of the film after completion of the longitudinal stretching by a roll coater. The composition is a polyester copolymer (Tg = 90 mol% of terephthalic acid / 4 mol% of isophthalic acid / 5 mol of 5-sodium sulfoisophthalic acid and 90 mol% of ethylene glycol / 10 mol% of diethylene glycol). Acrylic copolymer (Tg = 40) consisting of 62% by weight of polyester and 70% by mole of methyl methacrylate / 40% by mole of ethyl acrylate / 5% by mole of N-methylolacrylamide / 2% by mole of 2-hydroxyethyl methacrylate acrylic 20 wt% consisting ° C.), waxes (carnauba wax) 3% by weight of silica filler (average diameter: 0.1 [mu] m) 5% by weight, wetting agent (polyoxyethylene (n = 7) lauryl ether) 10% by weight.
This film was subsequently dried at 95 ° C., stretched 3.8 times in the transverse direction at 120 ° C., and thermally fixed by shrinking 3% in the width direction at 220 ° C. to obtain a film having a thickness of 188 μm. The thickness of the coating film was 0.1 μm. Since the number of foreign matters tended to increase over time, comparison was made when the filtration amount (m ³ ) / filtration area (m ² ) was 40.

<Film of coating film B>
As a lubricant, porous silica particles having an average particle size of 1.7 μm, which are aggregated particles, were added to 0.066 wt% with respect to the polymer, and the mixed polyethylene terephthalate chips were dried at 170 ° C. for 3 hours, and then put into an extruder. It was supplied, melted at a melting temperature of 295 ° C., filtered through a filter device 80, stretched 3.6 times, and rapidly cooled to obtain a longitudinally stretched film. The ratio of recycled chips was 40%.
10% containing DEHESIVE 39005VP (100 parts), DEHESIVE 39006VP (100 parts by weight) manufactured by Asahi Kasei Wacker Silicone Co., Ltd., and A-187 (2 parts by weight) manufactured by Nihon Unicar Co., Ltd. on one side of the film after completion of the longitudinal stretching. A concentrated aqueous solution was applied with a roll coater so that the film thickness after dry transverse stretching was 0.04 μm.
After coating, it was supplied to a stenter and stretched 3.9 times in the transverse direction at 120 ° C. The obtained biaxially oriented film was heat-fixed at a temperature of 205 ° C. for 5 seconds and wound into a roll to obtain a film having a thickness of 30 μm. Since the number of foreign matters tended to increase over time, comparison was made when the filtration amount (m ³ ) / filtration area (m ² ) was 40.

Comparative Examples 1-5
Table 1 shows a comparative example of one in which no film removal treatment was performed in the regeneration process, one having a small hugging angle, one having a fast brush surface speed relative to the film, and one having a slow surface speed. The gel-like foreign material accumulated in the recycling chip rises and saturates after repeated recycling. The amount of foreign matter was compared after the amount of filtration corresponding to five or more cycles, which was almost saturated, was reached. When the film removal treatment is not performed, or when the hugging angle and the brush surface speed / film speed are not within the scope of the present invention, the amount of foreign matter is larger than that of the embodiment, and “×” is indicated in the operation state of the film removal apparatus. It became. “X” means that the film was cut during the removal of the coating, and a manual re-input operation was required on the way, and continuous processing could not be performed.

  According to the present invention, in the production of a thermoplastic resin film, a film with few foreign substances can be produced. Moreover, it contributes to the life extension of the polymer filter for removing foreign substances. In the film manufacturing process for efficiently reusing waste film, the waste utilization ratio can be increased. By these, the film manufacturing cost can be reduced.

DESCRIPTION OF SYMBOLS 1 Measurement process 2 Drying process 3 Extruder 4 Polymer filter 5 Slit die 6 Cooling drum 7 Uniaxial stretching machine 8 Coater 9 Biaxial stretching machine 10 Conveying process 11 Ear part (edge film)
12 Winding machine 13 Mill roll 14 Slit process (slitter)
15 Packing process 16 Cutting 17 Core part (core film)
18 Crushing process 19 Flakes storage / drying 20 Regeneration extruder 21 Pelletizer 22 Chip (pellet)
23 Molten resin 24 Unstretched film 25 Uniaxially stretched film 26 Biaxially stretched film 27 Product 28 Flakes
29 Chip receiving / storage 30 Film removal equipment 70 Film 71 Chamber 72 Guide roll 73 Nip roll 74 Rotary brush 75 Holding angle 77 Brush rotation direction 79 Suction port 80 Suction nozzle 81 Suction (to dust collector)

Claims (10)

  When a film having a coating provided on at least one surface of a melt-extruded base film is run, a rotating brush having metal fiber bristles is brought into contact with the coating and the coating is removed. A method for removing a film surface coating, wherein the holding angle with a base film is 20 ° or more, and the surface speed of the rotating brush is 10 to 300 times the running speed of the film.   The film surface coating removal method according to claim 1, wherein the coating and the rotating brush are contacted by a guide roll installed in the vicinity of the rotating brush.   The removal method of the film surface film of Claim 1 or 2 from which the rotation direction of the rotating brush in the contact surface with a film differs from the running direction of a film.   The method for removing a film surface coating according to any one of claims 1 to 3, wherein the base film is a polyester film.   The method for removing a film surface film according to any one of claims 1 to 4, wherein the film is a silicone-based film.   A traveling film for traveling a film having a coating provided on at least one side of a base film and a rotating brush having metal fiber bristles, guiding the traveling film to a guide roll, and traveling film The coating film is removed by bringing a rotating brush into contact with the upper film while maintaining a holding angle of 20 ° or more, and setting the surface speed of the rotating brush to 10 to 300 times the running speed of the film. An apparatus for removing a film surface coating. The apparatus for removing a film surface coating according to claim 6 , wherein the removed coating is removed by suction with a suction nozzle. The apparatus for removing a film surface coating according to claim 6 or 7 , wherein the rotation direction of the rotary brush on the contact surface with the film is different from the traveling direction of the film. The apparatus for removing a film surface coating according to any one of claims 6 to 8 , wherein the base film is a polyester film. The apparatus for removing a film surface coating according to any one of claims 6 to 9 , wherein the coating is a silicone-based coating.

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