WO2009078639A1

WO2009078639A1 - Medical port tube for extrusion molding device and process for producing the same

Info

Publication number: WO2009078639A1
Application number: PCT/KR2008/007409
Authority: WO
Inventors: Bung-Gul Lee
Original assignee: Bung-Gul Lee
Priority date: 2007-12-17
Filing date: 2008-12-15
Publication date: 2009-06-25
Also published as: KR100925249B1; KR20090064986A

Abstract

A medical port tube extrusion molding device (100) and method are provided. The medical port tube extrusion molding device (100) and method can form a tube of uniform thickness and outer diameter by preventing deformation due to self-weight and contraction of the tube. The medical port tube extrusion molding device (100) includes first, second and third extruders (10a), (10b) and (10c) receiving, softening and melting respectively different resin materials, and supplying after mixing and compressing the melted resin materials, molding dies (20) respectively receiving the melted resin materials from the first, second and third extruders (10a) (10b) and (10c), and vertically extruding a multi-layer tubular tube (T), a vacuum sizing tank (30) stabilizing an external shape of the tubular tube (T) pushed out from the molding dies (20) using cooling and vacuum pressure, a take-up roller (40) pulling and conveying the tube (T) that has passed through the vacuum sizing tank (30) at a predetermined speed, a cooling water tank (50) cooling the tube (T) guided and conveyed by the take-up roller (40), and a blower (60) installed at an end of the cooling water tank (50) in a moving direction of the tube (T) and drying the surface of the tube that has passed through the cooling water tank (50).

Description

MEDICAL PORT TUBE FOR EXTRUSION MOLDING DEVICE AND PROCESS FOR PRODUCING THE SAME

Technical Field

[1] The present invention relates to a medical port tube extrusion molding device and method, and more particularly, to a medical port tube extrusion molding device and method that can form a tube of uniform thickness and outer diameter by preventing deformation due to self-weight and contraction of the tube. Background Art

[2] DEHP, an artificial chemical material belonging to the phthalate family, is widely used as a plasticizer for softening medical instruments made of PVC, such as blood transfusion sets, blood bags, fluid bags, tubes, etc. This material is known to lead to adverse effects on the human body such as cancer and reproductive disorders, and is classified by the World Wildlife Fund (WWF) as one of 67 environmental hormones (endocrine disruptors).

[3] Accordingly, in developed countries, DEHP regulation standards have been prepared and its use is restricted in the areas of food, environment, medicine, etc. Keeping pace, various medical instruments made of non-PVC materials such as PP or PET, etc. are being developed and distributed.

[4] In particular, a port tube that connects to a fluid bag should have sufficient flexibility, while facilitating thermal bonding to the fluid bag and an airtight cap and stably maintaining airtightness. And in the case of a multi-layered structure, the port tube is required to have the structural property of layers not separating.

[5] As a method of fabricating such a medical port tube, a tube extrusion method of passing melted resin through a mold having an intended shape to thereby extrude in the form of a tube is widely employed in industry.

[6] However, using such a conventional tube extrusion method, it was very difficult to obtain a port tube of fixed mold quality. When thermoplastic resin such as PP, PET, etc. is melted, it has the unstable property of its intrinsic viscosity becoming very low, and while a port tube that has passed through the mold and been extruded in tube form passes through a cooling water tank, the port tube is affected by gravity and sags downward. This causes the port tube to be molded thin on top and thick on the bottom, so that an overall uniform circle cannot be achieved.

[7] Also, regarding characteristics of the shape of a hollow tube, not only does local deformation of the tube occur due to pressure changes inside the mold in the tube extrusion process, but since the tube pushed through the mold is promptly pulled and wound by a winding roller, deformation due to pulling occurs as well.

[8] Moreover, the tube that has passed through the cooling water tank gets wound on the winding roller in a state in which moisture has not been completely removed from its surface, causing concern about improper hygiene such as breeding of microorganisms. Thus, conventional tube extrusion devices were poorly suited for producing medical tubes.

[9] The present inventors considered various problems such as those described above and spent many years researching the development of a medical port tube extrusion molding device and method that make it possible to prevent deformation due to self- weight and contraction of a tube and are free of concerns about improper hygiene. As a result, the present invention was conceived and completed. Disclosure of Invention Technical Problem

[10] Accordingly, an object of the present invention is to provide a medical port tube extrusion molding device and method capable of preventing deformation due to self- weight and contraction of a molded product.

[11] Another object of the present invention is to provide a medical port tube extrusion molding device and method that make it possible to obtain a sanitary medical port tube. Technical Solution

[12] In order to achieve the above objects, the present invention provides a medical port tube extrusion molding device including: first, second and third extruders receiving, softening and melting respectively different resin materials, and supplying after mixing and compressing the melted resin materials; molding dies respectively receiving the melted resin materials from the first, second and third extruders, and vertically extruding a multi-layer tubular tube; a vacuum sizing tank stabilizing an external shape of the tubular tube pushed out from the molding dies using cooling and vacuum pressure; a take-up roller pulling and conveying the tube that has passed through the vacuum sizing tank at a predetermined speed; a cooling water tank cooling the tube guided and conveyed by the take-up roller; and a blower installed at an end of the cooling water tank in a moving direction of the tube and drying the surface of the tube that has passed through the cooling water tank.

[13] The present invention also provides a medical port tube extrusion molding method including: a first process of respectively supplying different resin materials through a hopper to first, second and third extruders; a second process of softening and melting each of the resin materials supplied to the extruders by heating, and pushing the resin materials in a mixed and compressed state by turning of screws through molding dies and vertically extruding a tubular rube; a third process of stabilizing the rube extruded from the molding dies into a predetermined shape by using cooling water and vacuum pressure of a vacuum sizing tank; a fourth process of cooling the tube that has passed through the vacuum sizing tank by continuously pouring cooling water on the surface of the tube; a fifth process of again cooling the tube by passing the cooled tube through a cooling water tank, and a sixth process of drying the surface of the twice cooled tube using a blower.

Advantageous Effects

[14] Not only can the present invention having the above-described structure prevent sagging due to self- weight, etc. because the tube is extruded through an opening in the molding dies in the direction of gravity, but it also has the effect of stably maintaining a pressure difference between the inside of the tube and the vacuum sizing tank and molding the outer diameter of the tube in a uniform circular shape because the tube extruded by the molding dies is supplied with a predetermined pressure at its inside using an air nozzle while passing through the vacuum sizing tank.

[15] Also, in the present invention, since more than one vacuum sizing tank is installed from top to bottom at a predetermined interval, vacuum pressure of each of the vacuum sizing tanks can be controlled more efficiently. This provides the advantage of being able to form the outer diameter of the tube more uniformly. It also has the effect of reducing stretching and contraction of the tube by reducing friction between the tube and the vacuum sizing tank, thereby enabling product defect rate to be minimized.

[16] Also, the present invention has the effect of vastly improving tube cooling efficiency because the tube that has passed through the vacuum sizing tank is conveyed while in direct contact with cooling water pouring from a cooling water supply pipe.

[17] Also, the present invention has the effect of being able to prevent breeding of microorganisms such as bacteria because moisture is completely removed from the surface of the tube formed while passing through the cooling water tank. Brief Description of the Drawings

[18] FIG. 1 is a schematic diagram showing the constitution of a medical port tube extrusion molding device according to an exemplary embodiment of the present invention;

[19] FIG. 2 is a side cross-sectional view of molding dies of a medical port tube extrusion molding device according to an exemplary embodiment of the present invention; and

[20] FIG. 3 is a front cross-sectional view of a port tube extruded by a medical port tube extrusion molding device according to an exemplary embodiment of the present invention.

[21] <Description of Symbols of Main Parts in Drawings> [22] 10: Extruder 11 : Hopper

[23] 20: Molding dies 21: Injection port

[24] 22: Extrusion channel 23: Opening

[25] 24: Hollow part 28: Air nozzle

[26] 30: Vacuum sizing tank 38: Cooling water supply pipe

[27] 40: Take up roller 50: Cooling water tank

[28] 60: Blower 70: Winding means

[29] 100: Extrusion molding device

Mode for the Invention

[30] Hereinafter, a structure according to an exemplary embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

[31] It is hereby stated that some terms used below have been chosen for their ability to describe functions of the present invention, and they should be interpreted as having their normal meanings within the technical context of the present invention.

[32] Also, detailed description of well-known structures or functions related to the present invention will be omitted when deemed that such description could cloud the essential features of the present invention.

[33] FIG. 1 is a schematic diagram showing the constitution of a medical port tube extrusion molding device according to an exemplary embodiment of the present invention, FIG. 2 is a side cross-sectional view of molding dies of a medical port tube extrusion molding device according to an exemplary embodiment of the present invention, and FIG. 3 is a front cross-sectional view of a port tube extruded by a medical port tube extrusion molding device according to an exemplary embodiment of the present invention. As shown in FIGS. 1 through 3, a medical port tube extrusion molding device 100 according to an exemplary embodiment of the present invention includes first, second and third extruders 10a, 10b and 10c, molding dies 20, a vacuum sizing tank 30, a take up roller 40, a cooling water tank 50 and a blower 60.

[34] First, the first, second and third extruders 10a, 10b and 10c are configured to heat and melt pellets of different resin materials supplied using hoppers 1 Ia, 1 Ib and 1 Ic into a gel state and then convey forward while mixing and compressing by turning of screws.

[35] The molding dies 20 are for extruding a tubular tube by passing the gelatinous resin supplied at a predetermined pressure by the first, second and third extruders 10a, 10b and 10c through an opening 23. The molding dies 20 are installed such that the resin melted by the first, second and third extruders 10a, 10b and 10c, while simultaneously pushed out vertically, forms a multilayer tube T having an inner layer Tl, a middle layer T2 and an outer layer T3. [36] Such molding dies 20 are formed such that a first extrusion channel 22a, a second extrusion channel 22b and a third extrusion channel 22c join at the opening 23 between injection ports 21a, 21b and 21c respectively connected to the first, second and third extruders 10a, 10b and 10c and the opening 23 through which the melted resin is pushed out. Accordingly, as the melted resin supplied from the first, second and third extruders 10a, 10b and 10c through the injection ports 21a, 21b, and 21c passes through the first, second and third extrusion channels 22a, 22b and 22c and is pushed out of the opening 24, the tube T having three layers with respectively different diameters is extruded as one body.

[37] Also, an air nozzle 28 supplying air at a predetermined pressure transferred from a separate air supply apparatus to the hollow part 24 of the molding dies is installed at the top of the molding dies 20.

[38] Thus, the inside of the tube T extruded through the opening 23 of the molding dies is maintained at a predetermined pressure that is the same as air pressure by air supplied at a minute pressure through the air nozzle 28. When the tube T in such a state passes through the vacuum sizing tank 30, the surface of the tube is subjected to expansive pressure due to a pressure difference between the inside of the tube and the vacuum sizing tank 30. In response to this expansive pressure, the surface of the tube is formed in a uniform shape.

[39] The vacuum sizing tank 30 stabilizes the shape of the resin extruded in tube form through the molding dies 20. By applying pressure using the pressure difference between the inside and outside of the tube formed while being pushed out from the opening 23 of the molding dies, the outer shape is maintained and the tube T is cooled using cooling water filled inside.

[40] Also, the vacuum sizing tank 30 is connected to an outside vacuum pump (not shown) for evacuating its inside, and to an outside circulation pump (not shown) and a cooling tank (not shown) which continuously circulate the cooling water in order to maintain the cooling water at a predetermined temperature.

[41] In addition, the vacuum pressure and cooling water temperature of the vacuum sizing tank 30 are controlled by a pressure sensor for controlling vacuum pressure (not shown) and a temperature sensor (not shown) for controlling the temperature of cooling water.

[42] More than one vacuum sizing tank 30 is arranged from top to bottom at a predetermined interval so that cooling speed of the tube T can be adjusted and the tube T is more stably cooled and hardened. Also, as friction between the tube T and the vacuum sizing tanks 30 is reduced, stretching and contraction deviation decreases, so that deformation of the tube T according to air pressure, self- weight or tension can be completely prevented. [43] Here, the vacuum pressure inside the vacuum sizing tank 30 is preferably set to

190mmHg - 230mmHg.

[44] The cooling water supply pipe 38 is installed below the vacuum sizing tank 30 in a form enveloping the tube and performs a function of pouring cooling water supplied from outside down the surface of the tube.

[45] As the tube that has passed through the vacuum sizing tank 30 is cooled by the cooling water supply pipe 38, a stable shape can be maintained much more rapidly.

[46] The take-up roller 40 is installed below the vacuum sizing tank 30 and performs a function of pulling the tube T that has passed through the vacuum sizing tank at a predetermined speed while rotated by a driving source such as a motor and conveying the tube T to the cooling water tank 50.

[47] The tube passing the take-up roller 40 passes at least one guide roller and is conveyed to the cooling water tank 50.

[48] Here, it is preferable that outside of the take-up roller 40 is formed in the shape of a water tank so that cooling water flowing through the cooling water supply pipe 38 and down the tube can be temporarily stored and circulated to a separate cooling tank (not shown).

[49] The cooling water tank 50, which cools the tube T conveyed by the take-up roller 40 again, is installed to be filled with cooling water and maintain a predetermined temperature while cooling water is circulated by a circulation pump (not shown) and a cooling tank (not shown).

[50] The cooling water tank 50 is equipped with a water level sensor (not shown) and a cooling water supply pump (not shown) that control the cooling water so that the tube is submerged to a predetermined depth, and a temperature sensor (not shown) for controlling the temperature of cooling water.

[51] The blower 60 is installed at an end of the cooling water tank 50 in a moving direction of the tube and performs a function of drying and removing moisture such as water droplets on the surface of the tube that has passed through the cooling water tank.

[52] When the tube T whose surface is completely dried by the blower 60 is transported or stored, breeding of microorganisms such bacteria can be prevented.

[53] Here, the blower 60 is well known to those of skill in the art and thus its detailed description will be omitted.

[54] Meanwhile, in order to prevent contamination of the surface of the tube T by various bacteria and minute particles in the air, the medical port tube extrusion molding device 100 according to an exemplary embodiment of the present invention is preferably installed in a clean, well- ventilated room.

[55] Operation states of the above-described medical port tube extrusion molding device according to an exemplary embodiment of the present invention will be described below in connection with a medical port tube extrusion molding method using the same.

[56] First, the respectively different resin materials supplied through the hoppers l la, 1 Ib and 1 Ic of the first, second and third extruders 10a, 10b and 10c are heated and melted inside heating cylinders made of steel inside each extruder, transported forward while being mixed and compressed by turning of screws, and vertically supplied to the extrusion channels 22a, 22b and 22c of the molding dies through the injection ports 21a, 21b and 21c of the molding dies respectively connected to the extruders.

[57] The melted resin supplied in this way passes through the respective first, second and third extrusion channels 22a, 22b and 22c of the molding dies and is vertically extruded through the opening 23. At this time, the melted resin extruded through the opening 23 takes on a tubular form whose thickness and outer diameter are uniformly maintained by air supplied to the hollow part 24 of the molding dies through the air nozzle 28. While passing through the vacuum sizing tank 30, an inside/outside pressure difference is applied, i.e., air pressure is applied to the inside of the tube T and vacuum pressure is applied to the inside of the vacuum sizing tank 30 formed to envelop the tube T, and thus the tube T expands outward. This causes a more stable circular state to be maintained, and in that state, the tube T is rapidly cooled and hardened by cooling water.

[58] Also, the tube that has passed through the vacuum sizing tank 30, after having been cooled twice by cooling water continuously pouring through the cooling water supply pipe 38 installed below the vacuum sizing tank and running down the surface of the tube T, successively passes through the cooling water tank 50. In this process, since further cooling is performed using the cooling water filled inside the cooling water tank 50, the tube T maintains a much more stable state.

[59] Also, the tube T that has passed through the cooling water tank 50 has moisture such as water droplets on its surface completely removed by the blower 60, passes through a plurality of idle rollers and is wound on a reel by a winding means 70. While passing through the idle rollers, not only does natural cooling and drying occur due to air in the surrounding atmosphere or clean air of a clean room having separate equipment, but internal stress is completely removed and construction is miniaturized.

[60] Here, the winding means 70, like the blower 60, is well known to those of skill in the art and thus a detailed description of its structure will be omitted.

[61] While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

[1] A medical port tube extrusion molding device, comprising: first, second and third extruders receiving, softening and melting respectively different resin materials, and supplying after mixing and compressing the melted resin materials; molding dies respectively receiving the melted resin materials from the first, second and third extruders, and vertically extruding a multi-layer tubular tube; a vacuum sizing tank stabilizing an external shape of the tubular tube pushed out from the molding dies using cooling and vacuum pressure; a take-up roller pulling and conveying the tube that has passed through the vacuum sizing tank at a predetermined speed; a cooling water tank cooling the tube guided and conveyed by the take-up roller; and a blower installed at an end of the cooling water tank in a moving direction of the tube and drying the surface of the tube that has passed through the cooling water tank.

[2] The medical port tube extrusion molding device according to claim 1, wherein an air nozzle supplying air at a predetermined pressure transferred from a separate air supply apparatus to a hollow part of the molding dies is provided at the top of the molding dies.

[3] The medical port tube extrusion molding device according to claim 1, wherein first, second and third extrusion channels are formed in the molding dies between injection ports respectively connected to the first, second and third extruders and an opening through which the melted resin is extruded and pushed out, and a tubular tube having three layers with respectively different diameters is extruded as one body.

[4] The medical port tube extrusion molding device according to claim 1, wherein a cooling water pipe pouring cooling water supplied from outside down the surface of the tube that has passed through the vacuum sizing tank is installed at the bottom of the vacuum sizing tank.

[5] The medical port tube extrusion molding device according to any one of claims 1 through 4, wherein more than one vacuum sizing tank is arranged from top to bottom at predetermined intervals.

[6] The medical port tube extrusion molding device according to any one of claims 1 through 4, wherein in the cooling water tank, a predetermined water level and temperature are maintained while cooling water circulates.

[7] A medical port tube extrusion molding method, comprising: (a) a first process of respectively supplying different resin materials through a hopper to first, second and third extruders;

(b) a second process of softening and melting each of the resin materials supplied to the extruders by heating, and pushing the resin materials in a mixed and compressed state by turning of screws through molding dies and vertically extruding a tubular tube;

(c) a third process of stabilizing the tube extruded from the molding dies into a predetermined shape by using cooling water and vacuum pressure of a vacuum sizing tank;

(d) a fourth process of cooling the tube that has passed through the vacuum sizing tank by continuously pouring cooling water on the surface of the tube;

(e) a fifth process of again cooling the tube by passing the cooled tube through a cooling water tank, and

(f) a sixth process of drying the surface of the twice cooled tube using a blower.