JP2010137508A - Method of cutting cylindrical film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of cutting a cylindrical film, which can uniform a cut end of the cylindrical film including a thermoplastic resin or a thermoplastic elastomer composition without producing any problems of split. <P>SOLUTION: When the cylindrical film 1 including the thermoplastic resin or the thermoplastic elastomer composition is cut at a predetermined length, an expandable and shrinkable drum 2 to which the cylindrical film 1 is attached is used. The drum 2 has a gap 2C for cutting which extends circumferentially along a drum and has a width of 1-5 mm. After the cylindrical film 1 is arranged at the outer peripheral side of the drum 2 in a state of a diameter contraction so as to stride over the gap 2C for cutting, the drum 2 is diameter-expanded and the diameter-expanded drum 2 holds the cylindrical film 1 from the inside. A cutter 6 cuts the cylindrical film 1 over a round while moving along the gap 2C for cutting. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for cutting a tubular film made of a thermoplastic resin or a thermoplastic elastomer composition.

  In general, a tubular film made of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer in a thermoplastic resin is produced by inflation molding. In this inflation molding, air is supplied from the inside of a cylindrical film extruded from an extruder through a cylindrical die, and then inflated. Then, it is deformed into a flat shape by a guide means, and then flat by a pair of pinch rolls. And is wound around a roll of a winder (for example, see Patent Document 1). The long tubular film folded in a flat shape as described above is used after being cut into a predetermined length.

  2. Description of the Related Art Conventionally, as a method for cutting a long tubular film folded in a flat shape into a predetermined length, a method using a drum that can be expanded and contracted is known (see, for example, Patent Document 2). The drum is cut by a cutter in a state where the drum is expanded and the cylindrical film is held from the inside by a drum whose diameter is increased. When the tubular film is cut with a cutter in a state of being folded into a flat shape, there is a problem that the cut end becomes non-uniform (meandering or wavy), but the tubular film is cut in such a state that the tubular film is stretched like this. Thus, the cut end becomes uniform (straight), and the problem of non-uniform cut ends can be improved.

However, when the tubular film becomes thin, there is a problem that it is cut in a state where the cut end is raised (a jagged state), and an improvement thereof has been demanded.
JP 2005-125499 A Japanese Patent Laid-Open No. 11-90891

  The objective of this invention is providing the cutting method of the cylindrical film which can make the cut end of the cylindrical film which consists of a thermoplastic resin or a thermoplastic elastomer composition uniform, without producing the problem of raising. .

  The tubular film cutting method of the present invention that achieves the above object is a method of cutting a tubular film comprising a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer into a thermoplastic resin into a predetermined length. An expandable / retractable drum to which a cylindrical film is attached, the drum having a cutting gap of 1 to 5 mm in width extending along the circumferential direction of the drum, and the cylindrical on the outer peripheral side of the reduced diameter drum After arranging the film so as to straddle the gap for cutting, the drum is expanded and the cylindrical film is held from the inside by the drum whose diameter has been expanded, and then the cylindrical film is moved while moving the cutter along the cutting gap. It is characterized by cutting over the circumference.

  According to the above-described present invention, the tubular film can be cut in a state of being stretched in a cylindrical shape by the drum whose diameter has been increased, so that the cut end can be made uniform (straight). Moreover, by defining the gap for cutting the expandable / retractable drum to which the film is attached within the above-mentioned range, the amount of elongation of the tubular film when contacting the cutter is greatly suppressed, resulting in a uniform stretch state. Can be avoided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows an embodiment of a method for cutting a tubular film of the present invention, wherein 1 is a tubular film folded in a flat shape, and 2 is an expandable / contractable drum for attaching the tubular film. The long cylindrical film 1 is composed of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer in a thermoplastic resin, and is wound around a winding roll 3.

  The cylindrical drum 2 includes a drum main body 2A and a drum sub body 2B adjacent to the drum main body 2A in the width direction. A gap 2C for cutting is formed between the drum body 2A and the drum sub body 2B. The cutting gap 2C extends along the drum circumferential direction and has a width of 1 to 5 mm. The drum main body 2A and the drum sub-body 2B are each composed of a plurality of (for example, four) drum pieces 2A1 and 2B1 divided in the drum circumferential direction. The drum 2 is supported by the support means 4, and the expansion / contraction part 4A of the support means 4 is operated, so that the drum 2 (drum pieces 2A1, 2B1) is in the reduced diameter state shown in FIG. It is possible to expand and contract in the diameter state. The cylindrical film cutting method of the present invention uses such an expandable / contractible drum 2 and cuts as follows.

  First, as shown in FIG. 1A, the front end portion 1A of the tubular film 1 unwound from the take-up roll 3 is opened, and the opened front end portion 1A is on the outer peripheral side of one end portion of the drum 2 in a reduced diameter state. In this state, the plurality of suction pads 5 are sucked and held from the outside.

  Next, as shown in FIG. 1 (B), the suction pad 5 holding the tip 1A of the tubular film 1 is moved to the other end of the drum 2 in the drum width direction. Thereby, the cylindrical film 1 is arrange | positioned so that the clearance gap 2C for cutting | disconnection may be straddled on the outer peripheral side of the drum 2 of a reduced diameter state. In FIG. 1 (B), the cutter 6 moves together with the suction pad 5. This is because the suction pad 5 and the cutter 6 are supported by the same support means 8, and the support means 8 moves, so that the suction pad 5 is moved. This is because they are moved.

  After the arrangement of the tubular film 1, as shown in FIG. 1C, the diameter of the drum 2 is expanded, and the tubular film 1 is held from the inside by the drum 2 having an expanded diameter. As a result, the cylindrical film 1 held on the drum 2 is in a stretched state (a state in which tension is uniformly applied). After the holding, the suction pad 5 releases the suction, moves to the outer peripheral side, and further returns (moves) to one end of the drum 2.

  Next, as shown in FIG. 1D, the suction pad 5 sucks and holds the portion 1B of the tubular film 1 held by the drum sub body 2B adjacent to the cutting gap 2C from the outside. In order to increase the holding force, it is preferable to hold the tubular film 1 from the outside by the suction pad 5 before cutting with the cutter 6 as described above, but only holding by the drum 2 may be used.

  After being held by the suction pad 5, the cutter 6 disposed above the cutting gap 2 </ b> C descends and starts cutting the tubular film 1 at the position of the cutting gap 2 </ b> C. As the cutter 6 used here, a round blade type cutter driven by a motor is preferably used. The cylindrical film 1 is cut over one circumference while the rotating cutter 6 is moved in an annular shape along the cutting gap 2C. Thereby, the long tubular film 1 is cut into a tubular film piece 1M having a predetermined length. Since the cylindrical film 1 is cut in a cylindrical state by the drum 2 having an enlarged diameter, the cut end of the cylindrical film 1 becomes uniform (straight).

  When the cutting is completed, as shown in FIG. 1 (E), the holding pad 5 retreats to the outer peripheral side while adsorbing and holding the new tip 1A of the long tubular film 1, while the support means 4 is shown in FIG. Move to the left side of After the movement, as shown in FIG. 1 (F), the support means 4 turns to move the drum 2 to a position where the cut cylindrical film piece 1M is delivered to the next step. Therefore, when the cut cylindrical film piece 1M is removed from the drum 2, the support means 4 turns in the reverse direction, and the drum 2 returns to the state shown in FIG.

  The inventors of the present invention diligently studied about the problem that the tubular film 1 made of the thermoplastic resin or the thermoplastic elastomer composition is crushed at the time of cutting, and found the following.

  Since the tubular film 1 has elasticity, the tubular film 1 is stretched by being pulled by the contacting cutter until the cutter contacts and cuts the film. It was found that when the amount of elongation was not uniform at the location to be cut, a whirling (jagged state) occurred at the cutting end during cutting. Therefore, in order to make this amount of elongation constant, attention was paid to a cutting gap through which the cutter passes. In this gap portion, the tubular film is not held by the drum, and thus becomes free. If this free state is large, that is, if the width of the gap is large, the amount of elongation increases, and the degree of rolling increases substantially in proportion to it. Conversely, it was found that when the free state is small, that is, when the width of the gap is small, the amount of elongation decreases, and the degree of crushing tends to decrease approximately in proportion thereto.

  Therefore, when the width of the cutting gap is changed and examined closely, the width is reduced to 5 mm or less, and the amount of elongation at the time of contact with the cutter is largely suppressed, resulting in a uniform state, and the problem of fluffing is improved. I knew it was possible. Therefore, in the present invention, the width of the cutting gap 2C provided in the expandable / retractable drum 2 to which the tubular film 1 is attached as described above is set to 5 mm or less. Thereby, it becomes possible to cut the cylindrical film 1 uniformly (straight) without causing a problem of flapping at the cut end. If the width of the cutting gap 2C is narrower than 1 mm, the cutting edge of the cutter 6 inserted into the gap has a risk of coming into contact with the drum 2, so the width is set to 1 mm or more.

  In the present invention, preferably, as shown in FIG. 2, after the suction pad 5 sucks and holds the front end portion 1 </ b> A of the tubular film 1, the drum is placed in the opened tubular film 1 before the suction pad 5 is moved. The air blowing is started from the air blowing portion 7 provided in 2, and the air is blown during the movement of the suction pad 5, thereby opening the tubular film 1 unwound from the take-up roll 3. Good. If the tubular film 1 is thin, the upper film portion 1x and the lower film portion 1y may stick to each other and close even if the front end portion 1A is opened. If the suction pad 5 is moved in this state, the tubular film 1 may be caught on the edge portion of the drum 2, and the tubular film 1 may fall off from the suction pad or the portion of the tubular film 1 may be damaged. Therefore, it is possible to prevent this by providing a step of air blowing in this way and positively opening the tubular film 1. More preferably, as shown by a two-dot chain line in FIG. 2, a frustoconical guide member 10 is disposed at one end of the drum 2.

  As the above-described suction pad 5, the one shown in FIG. 3 can be preferably used. The suction pad 5 is formed in a circular arc shape along the outer peripheral surface of the drum 2, and a plurality of suction holes 5 </ b> B for sucking the tip end portion 1 </ b> A of the tubular film 1 are formed on the inner surface 5 </ b> A facing the drum 2. ing. The plurality of suction holes 5B have a configuration in which suction hole groups X1, X2, and X3 arranged in the direction D1 that is the drum circumferential direction are arranged in a plurality of rows (three rows in the figure) in the direction D2 that is the drum width direction. .

  Of the plurality of rows of suction hole groups X1, X2 and X3, the suction hole 5B of one suction hole group X3 is formed in a long hole shape having a width of 2 mm or less and extending in the direction D2 which is the drum width direction. The suction hole group X3 is arranged on the winding roll side (upstream side). The suction holes 5B of the remaining suction hole groups X1 and X2 are formed in a circular shape with a diameter of 2 mm or less, and a large number are arranged in a planar shape at a predetermined interval.

  By reducing the size of the suction holes 5B in this way, the suction force (suction pressure × hole area) per suction hole can be reduced, so that suction marks, that is, damage (elongation) to the tubular film 1 are reduced. Is reduced. On the other hand, the suction holding force when moving the suction pad 5 in the drum width direction is ensured by making the suction hole 5B of one suction hole group X3 into a long hole shape extending in the direction D2 which is the drum width direction. I am doing so.

  In addition, as shown in FIG. 4, the suction pad 5 is usually configured by closing the suction port of the pad main body 5M with a plate 5N and forming the suction hole 5B in the plate 5N. If the suction pad 5 having such a configuration is separated from the tubular film 1 where a part of the suction holes 5B are attracted, air enters the interior from the inside, and the negative pressure state cannot be maintained. Although it becomes impossible, even if a part of the suction holes 5B is separated by providing the suction holes 5B having such a small diameter and width, the amount of air flowing from the suction holes 5B is small, so that the suction holding force is maintained during the work. be able to. The lower limit of the size of the suction hole 5B is preferably 1 mm or more from the viewpoint of suction power.

  When the drum 2 is composed of a plurality of drum pieces 2A1 and 2B1 divided in the drum circumferential direction as described above, as shown in FIG. 5, between the drum pieces 2A1 and the drum pieces 2B1 formed during diameter expansion. A resin underlay member 13 for placing the tubular film 1 to be cut is preferably disposed in the gap portion 12 where the gap 11 and the cutting gap 2C intersect. In the gap portion 12, the tubular film 1 becomes easier to extend than other portions. Thus, by cutting the tubular film 1 with the cutter 6 on the underlaying member 13, the tubular film 1 is on the drum inner peripheral side at the time of cutting. It is possible to prevent the cut end from being stretched and to make the cut end into a good shape.

  In the present invention, when the tubular film 1 is used as a tire constituent member such as an inner liner layer which is an air permeation preventive layer of a pneumatic tire, a thermoplastic resin or a thermoplastic elastomer composition constituting the tubular film 1 is used. The storage elastic modulus of the object is preferably in the range of 25 to 500 MPa, and the thickness of the tubular film 1 is preferably in the range of 0.01 to 3 mm.

  If the storage elastic modulus is lower than 25 MPa, the strength is insufficient. Conversely, if it exceeds 500 MPa, the toughness is lowered and the durability is deteriorated. When the thickness is less than 0.01 mm, the air permeation resistance decreases. If the thickness exceeds 3 mm, it is not preferable in terms of weight. The storage elastic modulus mentioned here is a storage elastic modulus measured using a viscoelasticity spectrometer manufactured by Toyo Seiki Seisakusho under the conditions of static strain 10%, dynamic strain ± 2%, frequency 20 Hz, and temperature 20 ° C. .

  Examples of the thermoplastic resin used for the tubular film 1 include polyamide resins [for example, nylon 6 (N6), nylon 66 (N66), nylon 46 (N46), nylon 11 (N11), nylon 12 (N12). , Nylon 610 (N610), nylon 612 (N612), nylon 6/66 copolymer (N6 / 66), nylon 6/66/610 copolymer (N6 / 66/610), nylon MXD6 (MXD6), nylon 6T, nylon 6 / 6T copolymer, nylon 66 / PP copolymer, nylon 66 / PPS copolymer] and their N-alkoxyalkylated products, for example, methoxymethylated products of nylon 6, nylon 6/610 copolymerized Combined methoxymethylated product, nylon 612 methoxymethylated product, polyester resin [eg , Polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene isophthalate (PEI), PET / PEI copolymer, polyarylate (PAR), polybutylene naphthalate (PBN), liquid crystal polyester, polyoxyalkylene diimide di Aromatic polyester such as acid / polybutylene terephthalate copolymer], polynitrile resin [for example, polyacrylonitrile (PAN), polymethacrylonitrile, acrylonitrile / styrene copolymer (AS), (meth) acrylonitrile / styrene copolymer Polymer, (meth) acrylonitrile / styrene / butadiene copolymer], polymethacrylate resin [eg, polymethyl methacrylate (PMMA), polyethyl methacrylate], polyvinyl resin [eg , Vinyl acetate, polyvinyl alcohol (PVA), vinyl alcohol / ethylene copolymer (EVOH), polyvinylidene chloride (PDVC), polyvinyl chloride (PVC), vinyl chloride / vinylidene chloride copolymer, vinylidene chloride / methyl acrylate copolymer Polymer, vinylidene chloride / acrylonitrile copolymer], cellulose resin [for example, cellulose acetate, cellulose acetate butyrate], fluorine resin [for example, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polychlorofluoroethylene (PCTFE), tetrafluoroethylene / ethylene copolymer], an imide resin [for example, aromatic polyimide (PI)] and the like can be preferably used.

  The thermoplastic elastomer composition can be constituted by mixing an elastomer component with the above-described thermoplastic resin component. Examples of the elastomer used include diene rubbers and hydrogenated products thereof [for example, natural rubber (NR), isoprene rubber (IR), epoxidized natural rubber, styrene bradiene rubber (SBR), bradiene rubber (BR, high Cis BR and low cis BR), nitrile rubber (NBR), hydrogenated NBR, hydrogenated SBR], olefin rubber [eg, ethylene propylene rubber (EPDM, EPM), maleic acid modified ethylene propylene rubber (M-EPM), Butyl rubber (IIR), isobutylene and aromatic vinyl or diene monomer copolymer, acrylic rubber (ACM), ionomer], halogen-containing rubber [for example, Br-IIR, CI-IIR, bromine of isobutylene paramethylstyrene copolymer (Br-IPMS), chloroprene rubber (CR), hydride Rubber (CHR), chlorosulfonated polyethylene rubber (CSM), chlorinated polyethylene rubber (CM), maleic acid-modified chlorinated polyethylene rubber (M-CM)], silicone rubber [eg, methyl vinyl silicone rubber, dimethyl silicone rubber, Methyl phenyl vinyl silicon rubber], sulfur-containing rubber (for example, polysulfide rubber), fluorine rubber (for example, vinylidene fluoride rubber, fluorine-containing vinyl ether rubber, tetrafluoroethylene-propylene rubber, fluorine-containing silicon rubber, fluorine-containing phosphazene Rubbers], thermoplastic elastomers [for example, styrene elastomers, olefin elastomers, ester elastomers, urethane elastomers, polyamide elastomers] and the like can be preferably used.

  The composition ratio of the specific thermoplastic resin component (A) and the elastomer component (B) in the case of blending the thermoplastic resin and the elastomer is not particularly limited, and the film thickness, air permeation resistance, flexibility The weight ratio (A) / (B) is preferably 10/90 to 90/10, and more preferably 20/80 to 85/15.

  In the thermoplastic elastomer composition according to the present invention, in addition to the essential polymer component, another polymer such as a compatibilizer can be mixed as a third component. The purpose of mixing other polymers is to improve the compatibility between the thermoplastic resin and the elastomer component, to improve the molding processability of the material, to improve heat resistance, to reduce costs, etc. Examples of the material used include polyethylene (PE), polypropylene (PP), polystyrene (PS), ABS, SBS, and polycarbonate (PC).

A method for producing a thermoplastic elastomer composition is a method in which a thermoplastic resin component and an elastomer component (unvulcanized product in the case of rubber) are previously melt-kneaded with a twin-screw kneading extruder or the like to form a continuous phase (matrix). By dispersing the elastomer component as a dispersed phase (domain) in the plastic resin. When vulcanizing the elastomer component, a vulcanizing agent may be added under kneading to dynamically vulcanize the elastomer component. Further, various compounding agents (excluding the vulcanizing agent) to the thermoplastic resin or the elastomer component may be added during the kneading, but are preferably mixed in advance before kneading. The kneading machine used for kneading the thermoplastic resin and the elastomer component is not particularly limited, and a screw extruder, a kneader, a Banbury mixer, a biaxial kneading extruder, or the like can be used. Among them, it is preferable to use a twin-screw kneading extruder for kneading the thermoplastic resin and the elastomer component and for dynamic vulcanization of the elastomer component. Further, two or more types of kneaders may be used and kneaded sequentially. As conditions for melt-kneading, the temperature may be equal to or higher than the temperature at which the thermoplastic resin melts. The shear rate during kneading is preferably 2500 to 7500 Sec- ¹ . The entire kneading time is from 30 seconds to 10 minutes, and when a vulcanizing agent is added, the vulcanization time after addition is preferably from 15 seconds to 5 minutes. The thermoplastic elastomer composition produced by the above method is formed into a film by molding with a resin extruder or calendering. The method for forming a film may be a method for forming a film of a normal thermoplastic resin or thermoplastic elastomer.

  The method for cutting a tubular film of the present invention can be suitably used not only for cutting a thin tubular film in which the cut end is raised, but also for cutting a thicker tubular film.

  A cylindrical film having a thickness of 0.05 mm made of a thermoplastic elastomer composition (Br-IPMS and N6 / 66) having a storage elastic modulus of 168 MPa was changed as shown in Table 1 with the gap for cutting the drum that can be expanded and contracted changed as shown in Table 1. It cut | disconnected according to the cutting | disconnection method (this Example 1-5, comparative example) shown in 1. FIG. As the cutter, a round blade type cutter that is rotationally driven by a motor is used, the thickness of the blade edge is 1.8 mm, and the blade angle is 18 degrees.

  When the state of the cut end of each cut cylindrical film was observed, the results shown in Table 1 were obtained.

表１から、ドラムの切断用隙間を１〜５ｍｍにすることにより、筒状フィルムをささくれの問題を生じることなく均一（直線状）に切断できることがわかる。

From Table 1, it can be seen that by setting the gap for cutting the drum to 1 to 5 mm, the tubular film can be cut evenly (straight) without causing the problem of rolling up.

(A)-(F) is explanatory drawing which shows each process of one Embodiment of the cutting method of the cylindrical film of this invention. It is explanatory drawing which shows the process of spraying air in the opened cylindrical film. It is the enlarged view which looked at the suction pad from the inner surface side. It is an expanded sectional view of a suction pad. It is explanatory drawing of an underlay member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylindrical film 1A Front-end | tip part 2 Drum 2A1, 2B1 Drum piece 2C Cutting gap 3 Winding roll 5 Adsorption pad 5A Inner surface 5B Adsorption hole 6 Cutter 11 Crevice 12 Crevice part 13 Underlay member X1, X2, X3 Adsorption hole group

Claims (8)

A method of cutting a tubular film comprising a thermoplastic elastomer or a thermoplastic elastomer composition obtained by blending an elastomer into a thermoplastic resin into a predetermined length,
Using an expandable / contractible drum to which a tubular film is attached, the drum having a cutting gap with a width of 1 to 5 mm extending along the drum circumferential direction,
After disposing the tubular film across the gap for cutting on the outer peripheral side of the reduced-diameter drum, the drum is expanded and held from the inside by the drum whose diameter has been expanded, and then the cutter is separated from the cutting gap. The cutting method of the cylindrical film which cuts a cylindrical film over 1 round, moving along.   The tubular film cutting method according to claim 1, wherein the tubular film is a long tubular film wound up on a take-up roll and folded into a flat shape.   Open the end of a long tubular film rolled out from a take-up roll and hold it with a suction pad, then move the suction pad holding the front end of the tubular film in the drum width direction. The cylindrical film cutting method according to claim 2, wherein the cylindrical film is disposed on the outer peripheral side of the reduced diameter drum so as to straddle the gap for cutting.   The method for cutting a tubular film according to claim 3, wherein air is started to be blown into the opened tubular film before the suction pad is moved, and the air is blown during the movement of the suction pad.   The method for cutting a cylindrical film according to claim 3 or 4, wherein a portion of the cylindrical film adjacent to the cutting gap is held from the outside by a suction pad before being cut by a cutter.   The suction pad has a plurality of suction holes for sucking the tip of the cylindrical film on the inner surface facing the drum, and the suction holes are arranged in a drum width direction. The suction holes of one suction hole group of the plurality of rows of suction hole groups are shaped to extend in the direction of the drum width direction with a width of 2 mm or less, and the rest The cylindrical film cutting method according to claim 3, 4 or 5, wherein the suction holes of the suction hole group are formed in a circular shape having a diameter of 2 mm or less.   The drum is composed of a plurality of drum pieces divided in the drum circumferential direction, and an underlay member on which a tubular film to be cut is placed in a gap portion where a gap between the drum pieces formed at the time of diameter expansion and a gap for cutting intersect. The cutting method of the cylindrical film of any one of Claim 1 thru | or 6 which arrange | positions and cut | disconnects a cylindrical film on underlay in this clearance gap part.   The storage elastic modulus of the thermoplastic resin or the thermoplastic elastomer composition constituting the tubular film is 25 to 500 MPa, and the thickness of the tubular film is 0.01 to 3 mm. The cutting method of the cylindrical film as described in.

Images