JPS62201203A - Manufacture of thermoplastic resin sheet and device thereof - Google Patents

Abstract

PURPOSE:To make it possible to smoothly perform an extrusion process and consequently manufacture a thermoplastic resin sheet at high yield by a method wherein thermoplastic resin raw material is sent to the extrusion process after the thermoplastic resin raw material is checked whether it is mixed with foreign matters or not. CONSTITUTION:Tips, which are dried at a drying mechanism 2 by being supplied from a storage tank 1, are supplied through a transporting pipe 4 to an extrusion mechanism 3. When the tips pass through the transporting pipe 4, whether foreign matters mix with the tips or not is detected by a foreign matter detecting mechanism 7 on the upstream side. If the existence of foreign matters is detected, the transportation of the tips from the drying mechanism 2 is immediately stopped and the transporting passage is changed over outside the transporting pipe 4 at a foreign matter discharging mechanism 8 on the downstream side of the transporting pipe 4 so as to lead out the tips in the state mixed with foreign matters outside the transporting pipe 4 in order to remove the foreign matters. Further, foreign matters caught at a catching mechanism 73 is removed directly. After the completion of removal of the foreign matters, the foreign matter discharging mechanism 8 is restored to its original state so as to direct the transporting passage of the transporting pipe 4 to the extrusion mechanism 3 in order to repeat the manufacture of the titled sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for producing a thermoplastic resin sheet used as a support for photographic film such as X-ray film.

[Technology background]

For example, thermoplastic resin sheets used as supports for photographic films such as X-ray films are usually produced by extruding thermoplastic resin chips and then biaxially stretching.

As the thermoplastic resin chips, generally used are square pieces of several mm or cylindrical pieces of several mm made of polyester resin or the like.

[Problem that the invention seeks to solve]

In the production of thermoplastic resin sheets, for some reason, for example, workers may accidentally introduce foreign objects such as metal or ceramic tools, gloves, or cleaning cloths into the extrusion molding process during equipment maintenance. It may be mixed into the thermoplastic resin depth before it is mixed. If a thermoplastic resin chip containing such foreign matter is subjected to an extrusion molding process, it may become jammed in, for example, a part of the screw of the extrusion molding mechanism, and in the worst case, the screw may be damaged. However, there is a problem in that it requires a great deal of labor and time to repair, and the manufacturing process cannot be carried out during this time.

Furthermore, even if the foreign matter is small and the extrusion molding mechanism is not damaged, the product obtained by extrusion molding with foreign matter mixed in will be completely unusable, resulting in a decrease in yield. However, there is a problem in that it leads to an increase in manufacturing costs.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and its purpose is to manufacture a thermoplastic resin sheet with a high yield while being able to carry out the extrusion molding process smoothly. The objective is to provide a manufacturing method and device that can.

[Means for solving problems]

The method for producing a thermoplastic resin sheet of the present invention includes a step of extruding a thermoplastic resin raw material and then biaxially stretching the thermoplastic resin raw material, and after inspecting whether or not foreign matter is mixed in the thermoplastic resin raw material. It is characterized by subjecting a thermoplastic resin raw material to an extrusion molding process.

Further, the manufacturing apparatus of the present invention includes an extrusion molding mechanism, a transport pipe for transporting a thermoplastic resin raw material to the extrusion molding mechanism, and a biaxial stretching mechanism, and a foreign matter detection mechanism is provided on the upstream side of the transport pipe. It is characterized in that a foreign matter discharge mechanism is provided on the downstream side.

According to the manufacturing method of the present invention, since it is inspected whether or not foreign matter is mixed in the thermoplastic resin raw material before it is subjected to the extrusion molding process, it is possible to remove foreign matter if it is mixed in. Therefore, the extrusion molding process can be carried out without any problems, and the occurrence of defective products due to foreign matter can be prevented, making it possible to manufacture thermoplastic resin sheets with a high yield. Become.

Furthermore, according to the manufacturing apparatus of the present invention, the foreign matter detection mechanism is provided on the upstream side of the transport pipe to the extrusion molding mechanism, and the foreign material discharge mechanism is provided on the downstream side, so that the thermoplastic resin raw material passing through the transport pipe is The foreign matter detected can be detected by the foreign matter detection mechanism, and when the foreign matter is detected, the foreign matter can be immediately discharged from the transport pipe through the foreign matter discharge mechanism, making it possible to remove the foreign matter extremely efficiently.

The present invention will be explained in detail below.

In the manufacturing method of the present invention, before subjecting the thermoplastic resin raw material to the extrusion molding process, the thermoplastic resin raw material is inspected for the presence of foreign matter, and if no foreign matter is found as a result of the inspection, It is subjected to an extrusion molding process as it is to be extruded and then biaxially stretched to produce a thermoplastic resin sheet.

On the other hand, if the inspection results show that foreign matter has been mixed in, the transport of the thermoplastic resin raw material to the extrusion molding process is temporarily stopped, the foreign matter is removed from the thermoplastic resin raw material, and the thermoplastic resin raw material from which foreign matter has been removed is This is subjected to an extrusion molding process, and a thermoplastic resin sheet is manufactured in the same manner as described above.

Here, thermoplastic resin raw materials include thermoplastic resin chips,
Alternatively, a recycled chip, which will be described later, is added to this thermoplastic resin chip.

In the inspection for the presence of foreign objects, for example, a metal detector is installed on the transport route to detect foreign objects such as metal tools passing through the transport route, raw material chips are passed through the transport route, but large ones are A mesh member or the like is placed to prevent foreign objects such as gloves or cleaning cloths from passing through, and if such foreign objects are caught in the mesh member, it can be detected by opening the transport source, such as a rotary valve, etc. A means of determining the amount of raw material chips that have passed through the transportation route and reached the destination by measuring the time it takes to reach a set value. Various means can be employed, such as means for detecting a decrease in the dose using, for example, an electrical signal and thereby detecting a foreign object such as a ceramic tool.

According to such a manufacturing method, since it is inspected whether or not foreign matter is mixed in the thermoplastic resin raw material before subjecting it to the extrusion molding process, it becomes possible to remove foreign matter if it is mixed, Therefore, the extrusion molding process can be carried out without any problems, and the occurrence of defective products due to foreign matter can be prevented, making it possible to manufacture thermoplastic resin sheets with a high yield. .

As the thermoplastic resin chip, a small piece made of polyester resin in the shape of an angle of several mm or a column of several mm in size can be used, but it is not limited thereto. Particularly suitable polyester resins are those whose acid component is mainly terephthalic acid and whose alcohol component is mainly ethylene glycol, but may contain other acid components and/or alcohol components.

Examples of such other acid components include isophthalic acid, one or more naphthalene dicarboxylic acids, β-hydroxyethoxybenzoic acid, p-hydroxybenzoic acid, adipic acid, sebacic acid, etc. Other alcohol components include trimethylene glycol, tetramethylene glycol, hexamethylene glycol,
Examples include one or more fatty acids or alicyclic or aromatic dioxy compounds such as 1.4-cyclohexane dimetatool, and polyalkylene glycols such as polyethylene glycol.

Preferred polyester resins are those in which at least 80 mole percent of the repeating structural positions are ethylene terephthalate units.

In addition, during the manufacturing process, for example, after extrusion molding or biaxial stretching, that is, after vertical axis stretching and horizontal axis stretching, unnecessary parts of the sheet body are usually removed and sheet waste is generated. When collecting and reusing sheet waste, reusable chips are obtained by pulverizing sheet waste into a size of about several millimeters, or they are crushed and further semi-melted and processed into a size of about a few mm. When using the recycled chips obtained as a thermoplastic resin raw material and subjecting the mixture of the recycled chips and thermoplastic resin chips to an extrusion molding process, the presence or absence of foreign matter is inspected in the same manner as described above.

FIG. 1 is an explanatory diagram schematically showing an example of a manufacturing apparatus of the present invention. 1 is a storage tank for thermoplastic resin chips, 2 is a drying mechanism, 3 is an extrusion molding mechanism, 4 is a transport pipe for supplying dried chips from the drying mechanism 2 to the extrusion molding mechanism 3, and 5 is a longitudinal stretching mechanism. , 6 is a horizontal axis stretching mechanism.

7 is a foreign object detection mechanism, 8 is a foreign object discharge mechanism, the foreign object detection mechanism 7 is provided on the upstream side of the transport pipe 4, and the foreign object discharge mechanism 8 is provided.
is provided on the downstream side of the transport pipe 4.

The foreign object detection mechanism 7 includes, for example, a metal detector 71 that uses a high-frequency magnetic field and a ceramic detector 72 that uses an X-ray transmission method.
and a collection mechanism 73 such as a glove or cleaning cloth made of mesh material.

The foreign matter discharging mechanism 8 may be constructed of, for example, a lid member that can be opened and closed, and the foreign matter may be removed by manually opening and closing the foreign matter discharging mechanism 8 .

Further, an automatic switching valve linked to the foreign object detection mechanism 7 is provided in the foreign object discharge mechanism 8, and when a foreign object is detected by the foreign object detection mechanism 7, the automatic switching valve closes the pipe line of the transport pipe 4 to the extrusion molding mechanism 3. The transport path may be configured to be switched from the foreign matter discharge mechanism 8 to the outside of the transport pipe 4.

Reference numeral 9 denotes a container for storing chips discharged from the foreign matter discharge mechanism 8 and mixed with foreign matter. The chip containing foreign matter contained in this container 9 may be discarded, or
Alternatively, if necessary, only usable chips may be separated and supplied to a storage tank factory for reuse as raw materials.

In such a manufacturing apparatus, the thermoplastic resin chips supplied from the storage tank 1 to the drying mechanism 2 are dried while being stirred, for example. The chips after being dried by the drying mechanism 2 pass through a transport pipe 4 and are supplied to the extrusion molding mechanism 3. When the chips pass through the transport pipe 4, a foreign object detection mechanism on the first stream side 7, it is detected whether or not a foreign substance is mixed into the chip. If no foreign matter is detected here, the chip is directly transported to the extrusion molding mechanism 3 and extruded, then vertically stretched by the vertical stretching mechanism 5, and then horizontally stretched by the horizontal stretching mechanism 6, thereby making the thermoplastic resin manufactured sheets are manufactured. On the other hand, when a foreign object is detected by the foreign object detection mechanism 7, the transport of the chips from the drying mechanism 2 is immediately stopped by the rotary valve 21, and the transport path is changed to the transport pipe 4 by the foreign object discharge mechanism 8 on the downstream side of the transport pipe 4. The chip with foreign matter mixed therein is guided out of the transport pipe 4 from the foreign matter discharge mechanism 8 by being switched to the outside, thereby removing the foreign matter.

Further, the foreign matter collected in the collection mechanism 73 is directly removed from the collection mechanism 73, for example.

After the foreign matter has been removed in this way, the foreign matter discharge mechanism 8 is returned to its original state so that the transport path of the transport pipe 4 is directed toward the extrusion molding mechanism 3, and the manufacturing is repeated in the same manner. .

The thickness of the thermoplastic resin sheet obtained in this way is usually about 75 to 1,751 mm.

According to the above manufacturing apparatus, when a foreign object is mixed in the thermoplastic resin chip passing through the transport pipe 4, the foreign object is detected by the foreign object detection mechanism 7 provided on the upstream side of the transport pipe 4, and Since the foreign matter is led out of the transport pipe 4 from the foreign matter discharge mechanism 8 provided on the downstream side of the transport pipe 4, and the foreign matter collected by the collection mechanism 73 is removed from the collection mechanism 73, the foreign matter is extruded. Foreign matter is prevented from being transported to the molding mechanism 3, and as a result, there is no damage to the extrusion molding mechanism 3 caused by the foreign matter, and there is no foreign matter in the resulting thermoplastic resin sheet. The occurrence of non-defective products is avoided, and as a result, thermoplastic resin sheets can be obtained at a high yield while the extrusion molding process is carried out smoothly.

Although the above description has been made based on an example of a manufacturing apparatus, various embodiments are possible in the present invention.

For example, when used as a support for an X-ray film, a thermoplastic resin sheet colored with, for example, fine powder of a blue dye may be required in order to make the image easier to see during diagnosis using the X-ray film. In order to construct an apparatus capable of producing colored thermoplastic resin sheets in this manner, the apparatus is constructed by adding necessary components such as a storage tank for fine dye powder. Such fine dye powder usually has an average particle size of 1
Fine particle powder of about 5 to 30 trm is used.

When obtaining a colored thermoplastic resin sheet, the coloring density is selected to be an appropriate value as necessary in relation to the application and is not necessarily limited, but generally, in a colored thermoplastic resin sheet, The content ratio of the fine dye powder is selected so that the fine dye powder has an appropriate value, usually within the range of 200 to 300 ppm (by weight). Further, as the fine dye powder, fine powder of anthraquinone dye can generally be used, but it is not limited thereto.

〔Effect of the invention〕

As described above, according to the manufacturing method of the present invention, the thermoplastic resin raw material is inspected for foreign matter before being subjected to the extrusion molding process, so if foreign matter is present, it is removed. Therefore, the extrusion molding process can be carried out without any hindrance, and the occurrence of defective products due to foreign matter can be prevented, making it possible to manufacture thermoplastic resin sheets with a high yield. It becomes possible to do so.

Further, according to the manufacturing apparatus of the present invention, since the foreign matter detection mechanism is provided on the upstream side of the supply pipe to the extrusion molding mechanism and the foreign matter discharge mechanism is provided on the downstream side, the thermoplastic resin raw material passing through the supply pipe is When the foreign matter detecting mechanism detects a foreign matter mixed in the supply pipe, the foreign matter can be immediately discharged from the foreign matter discharge mechanism to the outside of the supply pipe, and the foreign matter can be removed extremely efficiently.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an outline of an example of a manufacturing apparatus. 1... Storage tank for thermoplastic resin chips 2... Drying mechanism 3... Extrusion molding mechanism 4
... Transport pipe 5 ... Vertical axis stretching mechanism 6 ...
- Horizontal axis stretching mechanism 7... Foreign object detection mechanism 71...
Metal detector 72... Ceramic detector 73... Collection mechanism 8... Foreign matter discharge mechanism 9... Container

Claims (1)

[Claims] 1) A step of extruding a thermoplastic resin raw material and then biaxially stretching the thermoplastic resin raw material, and after inspecting whether or not foreign matter is mixed in the thermoplastic resin raw material, the thermoplastic resin raw material is A method for producing a thermoplastic resin sheet, the method comprising subjecting it to an extrusion molding process. 2) It is equipped with an extrusion molding mechanism, a transport pipe for transporting the thermoplastic resin raw material to the extrusion molding mechanism, and a biaxial stretching mechanism, and a foreign object detection mechanism is provided on the upstream side of the transport pipe, and a foreign object detection mechanism is provided on the downstream side of the transport pipe. A thermoplastic resin sheet manufacturing device characterized by being equipped with a discharge mechanism.