JP2001293765A - Die device for extruding resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate an adherence of a deteriorated material to become a material of an eye mucus to be adhered to a die lip of a die for molding a thin film. SOLUTION: A plastic die 1 is formed with a slit by opening a gap at a pair of die bodies 1a, 1b. A molten plastic 3 is filled in the slit. Die lips formed of a die take-off side lip 4 and an opposite take-off side lip 5 are provided at distal ends of the bodies 1a, 1b. A photocatalyst is fixed to a part of the end of the lip 5 not contacted with at least the molten plastic. An exciting light source 11 is arranged at a distal end face of the lip 5 between the lip 5 and a casting drum 2 so as to irradiate the photocatalyst 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin extrusion molding die suitable for forming a film and a sheet for solving the problem that a die line is generated in a thin film such as a plastic film and a sheet due to a build-up adhered to the die. Related to the device.

[0002]

2. Description of the Related Art When a resin polymer is formed into a thin sheet and extruded from a slit-shaped die lip of an extrusion die to form a film, a strip-shaped projection called a die line may be generated. This is because, while the resin-made polymer is continuously extruded, deteriorating substances and the like adhere to the tip of the die lip in a ball shape, which may grow and cause a die line. Is called Meyani. Conventionally, when a die line is formed on a film or a sheet due to a build-up, in order to prevent this, the forming machine is stopped, the die is disassembled, and the build-up is removed, and the die is assembled again.

[0003] Techniques for reducing the rate of adhesion and deposition of scum on a molding machine and extending the cycle of disassembling and cleaning the die are disclosed in, for example, JP-A-9-207194 and JP-A-9-20719.
No. 5, etc. The technology disclosed in Japanese Patent Application Laid-Open No. 9-207194 is shown in FIGS. As shown in FIG. 3, an extrusion die 1 and a casting drum 2
Are arranged to face each other. When the extrusion molding die 1 extrudes the melting polymer 3, the extruding die 1 has a take-off lip 4 on the side to be taken into the sheet and an opposite take-off lip 5 on the opposite side.
Are provided. The corner portion 6 of the inner extrusion opening of the anti-take-off lip 5 is provided with an R (round) processed portion having an arc shape of 0.1 to 5.0 mm, and the take-off lip 4 has a corner portion in the same shape. Is leaving. Further, the extrusion die 1 shown in FIG. 4 is provided with a corner cut portion in which the corner 6 of the extrusion port of the anti-take-off side lip 5 is cut into an inclined plane.

As described above, by providing a specific processing, that is, an R-processed portion or a corner cut processing portion only on the anti-take-off side lip 5, the resin film 7 extruded from the extrusion die 1 can be used. 5, and is pulled away from the lip 4 on the take-up side, so that the adhesion growth of the lip is suppressed. As a result, the effect of preventing the generation of die lines is at least seven consecutive days, and stable molding is possible. Therefore, maintenance is extremely easy, which is beneficial for improving production efficiency.

The technique disclosed in Japanese Patent Application Laid-Open No. 9-207195 is shown in FIGS. 3 and 4 described above.
The same parts as those described above are denoted by the same reference numerals and described. In the extrusion die 1 shown in FIG. 5, the tip of the anti-take-off lip 5 of the pair of die lips 4, 5 is 0.1 to 5.0 mm or less, preferably 0.2 to 2 mm, higher than the take-off lip 4. .
Steps are provided at the extrusion ports of the die lips 4 and 5 so as to protrude toward the tip end within a range of 0 mm. The extrusion die 1 shown in FIG. 6 is further subjected to a rounding process in which the tip of the anti-take-off lip 5 is formed in an arc shape, and the extrusion die 1 shown in FIG. The corners are cut off diagonally.

[0006] Usually, the resin extruded from the extrusion die swells due to a phenomenon called a ballast effect.
Although the lip is easily attached to the take-off side lip 4, FIGS.
In the invention shown in FIG. 5, the resin lip 7 extruded is provided with a step so that the tip of the anti-take-off lip 5 is longer than the take-up lip 4 of the pair of die lips 4, 5. It is pulled rearward along the side lip 5 and moves away from the lower surface of the take-off side lip 4, so that the deteriorating substances are less likely to adhere. According to the present technology, since the effect of preventing the generation of the die line of the molding machine is continuous for 7 days or more and stable film molding is possible, the maintenance of the molding machine becomes extremely easy, which is useful for improving the production efficiency.

[0007]

The technology shown in FIGS. 3 to 7 is characterized in that the generation of mist is suppressed by optimizing the tip shape of the die lip, and the continuous operation period can be extended as compared with the conventional die. Although it is excellent, it does not reduce the adhesion of deteriorating substances, which are the basis of the soil, and thus there is a limit to further extending the continuous operation period. Therefore, it is considered that there is room for further improvement in the molding machine if the above-mentioned technique is used in combination with the means for reducing the adhesion of degraded substances. The present invention has been made in view of the above-described problems. For example, when a thermoplastic resin (such as polyester) is extruded into a sheet and formed into a film by a flat stretching method, a die lip for extrusion molding is used to form a die lip. It is an object of the present invention to provide a resin extrusion molding die that can remove a degraded substance in a very small amount when it adheres.

[0008]

In order to achieve the above object, a resin extrusion molding die according to the present invention is provided with a photocatalyst at the tip of the die in plastic molding, and a light source at a position where the photocatalyst can be irradiated with light. I have arranged. A photocatalyst is a substance that exerts a strong oxidizing action by irradiating the catalyst with light. Therefore, a photocatalyst is applied to the portion of the die lip to which the clay is attached, and an excitation light source that excites the photocatalyst is arranged near the die lip to irradiate the photocatalyst with the excitation light source, thereby degrading the base material of the clay. Can be decomposed before adhering to and depositing on the die lip. The above-mentioned plastic die has a photocatalyst applied to the tip of the die,
Light irradiation from a light source can be performed through a light guide material. As a result, a black light or mercury lamp is installed as a light source for photocatalyst excitation in the reflector, and the photocatalyst is irradiated with the excitation light source through the light guide material, so that the degraded material that becomes the base of the clay adheres to the photocatalyst portion. Decompose before depositing. Further, a drum is provided so as to face the tip of a pair of die lips disposed with a gap, and a die for forming a thin film of a thermoplastic resin extruded from the gap of the die lip on the drum, A photocatalyst is attached to the tip, and a light source of excitation light that excites the photocatalyst is provided corresponding to the tip, and the tip of the opposite take-off lip of the pair of die lips in the opposite direction to the thin film take-off side of the drum. Can be made to protrude beyond the tip of the take-off lip on the thin-film take-up side, and / or the corners of the anti-take-off lip can be cut into an arc or an inclined surface.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A resin extrusion die according to an embodiment of the present invention will be described below with reference to FIG. A plastic die (extrusion die) 1 of the resin extrusion die apparatus shown in FIG. 1 includes a pair of die bodies 1a,
A slit is formed in the slit 1b by forming a gap, and a molten plastic 3 is disposed in the slit. A die take-up side lip 4 and a non-take-up side lip 5 are formed at the tip of each of the die bodies 1a and 1b. Die lip is provided. In the present embodiment, the tip of the opposite take-off lip 5 of the die lip is more than 0.1 mm or more 5.0 mm than the tip of the take-up lip 4.
Hereinafter, a step is provided so as to protrude toward the distal end side, preferably in the range of 0.2 to 2.0 mm. In addition, an R-processed portion formed in an arc shape is provided in a corner portion 6 on the extrusion port side of one of the die lips on the side opposite to the take-off side lip 5.

A photocatalyst 1 is provided at the tip of the anti-take-off lip 5.
0 is attached. The photocatalyst 10 is attached to at least a portion of the tip of the anti-take-off lip 5 where the molten plastic 3 does not contact. As the photocatalyst, titanium oxide, zinc oxide, tungsten oxide, tin oxide or the like can be used alone or in combination of two or more thereof, and a trace additive such as chromium and platinum can be applied. As a method of attaching (fixing) to the die lip, thermal spraying, PVD, CVD, vapor deposition, sintering using an amorphous material of the same material as a binder, or the like can be applied.

An excitation light source 11 is arranged between the anti-take-off lip 5 and the casting drum 2 so as to irradiate the tip surface of the anti-take-off lip 5, ie, the photocatalyst 10. As the excitation light source 11, a light source that emits light capable of exciting a photocatalyst, such as a black light or a mercury lamp, can be used. The excitation light source 11 is illuminated over the entire width in the die width direction (perpendicular to the drawing) without creating a shadow on the photocatalyst 10 surface, and is fixed at a position close to the tip surface of the anti-take-off lip 5. Further, it is more preferable to attach the tip end of the take-off lip 4 with the same configuration.

When the molten plastic 3 is extruded into the atmosphere from the tips of the die lips 4 and 5 through the slit-shaped parallel walls of the plastic die 1, volatile components such as additives and degraded plastics and plastics are removed. Die 1
The low-molecular-weight degraded substances generated inside adhere to the tips of the die lips 4 and 5. When the deposits accumulate as described above, streaky projections called die lines are generated on a film or sheet as a product, resulting in a deterioration in quality. As in the present embodiment, a photocatalyst having a strong oxidizing effect is applied to the tip of the anti-take-off side lip 5 to which the lip is likely to adhere, and the photocatalyst 10 is constantly irradiated with light for exciting the photocatalyst 10. Deposits on the tip can be decomposed and removed in a very small amount.

If the photocatalyst 10 is also applied to the tip of the take-off lip 4, an effect of decomposing both ends of the lips 4 and 5 can be obtained. Furthermore, since the excitation light source 11 of the photocatalyst 10 generates ultraviolet rays, the action of decomposing the attached matter by the ultraviolet rays can be expected. As described above, in the present embodiment, light is efficiently applied to the photocatalyst 10, and while the amount of deposits and the like on the tips of the die lips 4 and 5 is extremely small, the photocatalyst is decomposed and removed by the photocatalyst, and the film and sheet are eliminated. The generation of a die line can be prevented.

Next, a resin extrusion molding die according to a second embodiment of the present invention will be described with reference to FIG. In the plastic die 1 shown in FIG. 2, a slit is formed in the pair of die bodies 1a and 1b with a gap therebetween, and molten plastic 3 is supplied into the slit.
A die lip formed from a die take-up side lip 4 and a non-take-up side lip 5 is provided at the tip of each of a and 1b. In the present embodiment, the tip of the opposite take-off lip 5 of the die lip is located at a tip side of 0.1 to 5.0 mm, preferably 0.2 to 2.0 mm from the tip of the take-up lip 4. Steps are provided to protrude. In addition, an R-processed portion formed in an arc shape is provided in a corner portion 6 on the extrusion port side of one of the die lips on the side opposite to the take-off side lip 5.

The photocatalyst 1
0 is attached. The photocatalyst 10 is attached to at least a portion of the tip of the anti-take-off lip 5 where the molten plastic 3 does not contact. As the photocatalyst 10, titanium oxide, zinc oxide, tungsten oxide, tin oxide or the like can be used alone or in combination of two or more thereof, or a trace additive such as chromium or platinum can be applied. As a method of attaching (fixing) to the die lip, thermal spraying, PVD, CVD, vapor deposition,
Sintering using an amorphous material of the same material as a binder is applicable.

An excitation light source 11 is disposed near the plastic die 1, and a reflection mirror 12 having a circular cross section is disposed around the excitation light source 11. As the excitation light source 11, a light source capable of exciting a photocatalyst such as a black light or a mercury lamp can be used. The excitation light source 11 is housed in a reflecting mirror 12 having a mirror-finished inner surface so as to reflect light, and a light guide 13 having a window for receiving light is attached to a part of the reflecting mirror 12 in a circumferential direction. The other end of the light guide member 13 is provided over the entire width of the opposite take-off lip 5, and
Is disposed in the vicinity of the photocatalyst 10 attached to the tip of the photocatalyst.
The cross section of the reflecting mirror 12 is shown as a circle, but is not limited to this, and may be a polygonal cross section. The light guide member 14 is a light source 11.
Any material that guides the excitation light to the photocatalyst 10 can be used, but a quartz molded product is desirable in terms of heat resistance and the like. In addition, it is preferable to attach the same configuration to the tip side of the take-off side lip 4.

Next, the operation of the resin extrusion die according to the second embodiment of the present invention will be described. In the present embodiment, the molten plastic 3
Is passed through the parallel slits of the plastic die 1 and is extruded into the atmosphere from the tip openings of the die lips 4 and 5, and volatile components such as additives and degraded plastics are formed in the slits of the plastic die 1. The generated low-molecular-weight degraded substances adhere to the tips of the die lips 4 and 5.
When this deposit is deposited, a streak-like projection called a die line is generated on a film or sheet as a product, resulting in a deterioration in quality.

As in the present embodiment, a photocatalyst having a strong oxidizing action is applied to the tips of the die lip 4, 5 and the light for exciting the photocatalyst is constantly irradiated, so that the die lip 4, 5
Debris on the tip is always decomposed and removed in a very small amount. The excitation light source 11 of the photocatalyst 10 is reflected by the inner surface of the reflecting mirror 12, efficiently enters the light guide 14, and irradiates the photocatalyst 10 from the other end. If it is applied to the tip of the take-off lip 4,
The effect is that a decomposition action occurs on both sides of the tip of the die lip 4,5. In the present embodiment, the light guide member 14 can be provided even when the excitation light source 11 cannot be provided nearby. Further, since the excitation light source 11 generates ultraviolet rays, it is expected that the ultraviolet rays generate a function of decomposing the attached matter.

As described above, according to the present embodiment, in order to efficiently irradiate the photocatalyst with light, the adhering matter to the tip of the lip is decomposed and removed by the photocatalyst in a very small amount, so that the film is eliminated. The generation of the die line of the sheet can be prevented. The embodiments of the present invention have been described above. However, the present invention is not limited to the embodiments, and various modifications can be made based on the technical idea of the present invention.
In the above embodiment, a step is formed between the take-off lip 4 and the anti-take-side lip 5 and an R-processed portion is provided. However, either or both of the step and the R-processed portion may be omitted. Good. In the case where only the R-processed portion is formed without a step, an R-processed portion in which the arc-shaped R-processed portion of the opposite lip 5 of the die lip is formed into an arc having a tip of 0.1 to 5.0 mm is provided. To do. Further, a corner cut processing section may be provided instead of the R processing section.

[0020]

As described above, according to the present invention, generation of a die line on a film or sheet as a product can be eliminated by preventing the die at the tip of the die. Therefore,
The molding machine can be used for a long time, and the running cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view showing the vicinity of a lip tip of a plastic die according to a first embodiment of the present invention.

FIG. 2 is a schematic view showing the vicinity of a lip tip of a plastic die according to a second embodiment of the present invention.

FIG. 3 is a schematic view of a conventional extrusion molding die (plastic die), showing a state in which a lip on the anti-take-off side is rounded.

FIG. 4 is a schematic view of a conventional extrusion die, showing a state in which a lip opposite to a take-off side is subjected to a corner cutting process.

FIG. 5 is a schematic view showing a conventional extrusion die, in which the tip of the tip on the opposite side is longer than the tip of the tip on the side.

FIG. 6 is a schematic view showing a conventional extrusion die in which the tip of the tip on the opposite side is longer than the tip of the tip on the opposite side, and the lip on the opposite side is rounded.

FIG. 7 is a schematic view showing a conventional extrusion die, in which the tip of the tip on the opposite side is longer than the tip of the tip on the opposite side, and the lip on the opposite side is corner-cut. .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plastic die 2 Casting drum 3 Molten plastic 4 Pick-up side lip 5 Anti-take-up side lip 6 Corner part 7 Resin film 10 Photocatalyst 11 Light source for excitation 12 Reflecting mirror 14 Light guide material

Claims (2)

[Claims] 1. A die lip tip of a thin film forming die formed by extruding a resin, wherein a photocatalyst is attached to an extruding edge of the die lip and an excitation light source for exciting the photocatalyst is provided. Die apparatus for resin extrusion molding. 2. A light guide member for guiding the excitation light of the light source for excitation of the photocatalyst to the photocatalyst, one end of the light guide member is disposed on the light source, and the other end of the light guide member is connected to the light source. 2. The die apparatus for resin extrusion molding according to claim 1, wherein the die lip is arranged near an edge of an extrusion opening of the die lip.