JP6788575B2 - Medical molded products, extrusion molding methods for medical molded products, and extrusion molding equipment for medical molded products - Google Patents

Description

The present invention relates to a medical molded product, an extrusion molding method for a medical molded product, and an extrusion molding device for a medical molded product.

Conventionally, a soft polyvinyl chloride resin has been widely used as a medical material. Medical devices are considered to be very safe because the blood they come in contact with is returned to the body, inserted into living tissues, or used near patients who are weak. Although it is generally used in a sterilized form, radiation sterilization, ethylene oxide sterilization or high-pressure steam sterilization is generally adopted as the sterilization method. Among them, radiation sterilization is excellent because unlike ethylene oxide sterilization, there is no concern about residual ethylene oxide gas and medical equipment is not exposed to high temperatures unlike high-pressure steam sterilization, so it is hygienic and causes little damage to medical materials. It is used as a sterilization method.

On the other hand, in a medical device made of a soft polyvinyl chloride resin composition, the soft polyvinyl chloride resin or a compounding agent thereof is deteriorated / denatured by radiation or heating, and problems such as promotion of coloring occur.

In view of the above problems, Patent Document 1 reports a molded product that does not easily discolor even during electron beam sterilization. The above-mentioned Patent Document 1 is characterized in that it is molded with a polyvinyl chloride resin composition containing a specific amount of 3-mercaptopropionic acid ester of a trihydric or higher polyhydric alcohol.

Japanese Unexamined Patent Publication No. 2012-05709

The molded product described in Patent Document 1 is certainly an excellent discoloration resistance to electron beam sterilization and is not easily discolored after electron beam sterilization.

On the other hand, medical molded products made of polyvinyl chloride resin are general-purpose products, and it is desired to manufacture them at a lower cost than other high-performance medical devices. Therefore, in consideration of cost reduction, it is desired to reduce the types and amounts of compounding agents (additives) as much as possible.

Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique capable of inexpensively manufacturing a medical molded product with reduced coloring (discoloration).

As a result of diligent research to solve the above problems, the present inventor has a low degree of coloring (high whiteness and low yellowness) even if the amount of metal soap as a heat stabilizer is reduced. We have found a technique for manufacturing a medical molded product made of vinyl resin, and have completed the present invention.

That is, the above objectives are 30 to 160 parts by mass of ester plasticizer, 5 to 25 parts by mass of epoxy plasticizer, and 0.01 to 0.1 parts by mass of zinc soap and calcium soap with respect to 100 parts by mass of polyvinyl chloride resin. Depending on the medical molded product, the composition containing the part (total amount) is extruded and has a whiteness (WI) of 25 or more and a yellowness (YI) of 3.5 or less. Achieved.

An extrusion molding method for a medical molded product that achieves the above object is to extrude the above composition and have a whiteness (WI) of 25 or more and a yellowness (YI) of 3.5 or less. This is an extrusion molding method for molding a medical molded product. First, the composition formed in a solid state is adjusted to an amount adjusted so as not to cause shearing heat generation in the composition in the extruder in the screw of the extruder formed to have the same groove depth. And supply. Heat from a heater is applied to the solid composition supplied to the screw to melt it. Then, the melted composition extruded from the extruder is molded into the shape of a medical molded product by a die.

An extrusion molding device for a medical molded product that achieves the above object extrudes the above composition and has a whiteness (WI) of 25 or more and a yellowness (YI) of 3.5 or less. It is an extrusion molding apparatus for molding a medical molded product. The extrusion molding apparatus supplies an extruder in which screws formed at the same groove depth are rotationally driven in a barrel, and the composition formed in a solid state to the screw, and the composition. A feeder that can adjust the supply amount of the mixture, a heater that applies heat to melt the solid composition supplied to the screw, and the melted composition extruded from the extruder of the medical molded product. It has a die that is molded into a shape. Then, the feeder adjusts the supply amount of the composition to an amount that does not cause shearing heat generation in the composition in the extruder.

The medical molded article of the present invention has a low degree of coloring (high whiteness and low yellowness) even with a small amount of metal soap. Therefore, the medical molded product of the present invention can be manufactured at low cost.

According to the extrusion molding technique of a medical molded product of the present invention, a composition formed in a solid state is subjected to shearing heat generation in the extruder by using screws formed to have the same groove depth. It is supplied in an amount adjusted so that it does not occur. Therefore, it is possible to prevent the composition from staying in the extruder, and further to prevent the composition from being excessively sheared and generated in the extruder. As a result of suppressing the two factors that cause the molded product to burn, it is possible to manufacture a medical molded product with a low degree of coloring (high whiteness and low yellowness) at low cost even with a small amount of metal soap. ..

It is a schematic block diagram which shows the extrusion molding apparatus of the medical molded article which concerns on embodiment of this invention. It is sectional drawing which shows the main part of the extrusion molding apparatus of the medical molded article shown in FIG.

The first of the present invention is 30 to 160 parts by mass of an ester plasticizer, 5 to 25 parts by mass of an epoxy plasticizer, and 0.01 to 0.1 parts by mass of zinc soap and calcium soap with respect to 100 parts by mass of a polyvinyl chloride resin. A medical molded product obtained by extruding a composition containing a portion (total amount) and having a whiteness (WI) of 25 or more and a yellowness (YI) of 3.5 or less. provide.

A medical molded product satisfying the above constitution has a low degree of coloring (high whiteness and low yellowness) even with a small amount of metal soap. Therefore, the medical molded product of the present invention can be manufactured at low cost.

In general, general-purpose medical polyvinyl chloride resin molded products are used for various purposes such as infusions, blood transfusion bags, and connecting tubes. At this time, the molded product is preferably low in yellow and high in white so that the state (for example, flow of liquid, color) of the content of the molded product (for example, blood, nutrients, etc.) can be easily observed. Is done. Therefore, as described in Patent Document 1, it has been conventionally attempted to suppress discoloration and coloring by using various additives. On the other hand, such general-purpose medical molded products are used in large quantities for various purposes, and therefore are required to be inexpensive. Therefore, from the viewpoint of cost reduction, it is preferable that the types and amounts of compounding agents (additives) are small. That is, there is a trade-off relationship between suppression / prevention of coloring and discoloration of medical molded products and cost reduction.

On the other hand, the medical molded article of the present invention is manufactured by a specific means as described in detail below, so that even a small amount of stabilizer (zinc soap and calcium soap) has a whiteness. It has become possible to produce medically molded products with high calcium content and low yellowness.

Hereinafter, the constituent components of the polyvinyl chloride resin composition according to the present invention will be described in detail. In addition, in this specification, "X to Y" indicating a range includes X and Y, and means "X or more and Y or less". Unless otherwise specified, the operation and physical properties are measured under the conditions of room temperature (20 to 25 ° C.) / relative humidity of 40 to 50%.

(Medical molded product)
The medical molded product of the present invention is produced by extrusion molding a specific composition (polyvinyl chloride resin composition) as described above. Further, the medical molded article of the present invention has a whiteness of 25 or more (WI) and a yellowness of 3.5 or less (YI). A molded product having a high degree of whiteness and a low degree of coloring (yellowness) exhibits high visibility, so that a liquid (for example, blood, a nutrient, etc.) is poured into the molded product (for example, a tube). However, the state (for example, liquid flow, color) can be visually recognized well.

Considering the effect of further improving visibility, the whiteness of the medical molded product is preferably 26 or more, more preferably 27 or more, and particularly preferably 28 or more. The higher the whiteness of the medical molded product, the more preferable it is. Therefore, no upper limit is set, but about 50 or less is sufficient. Similarly, in consideration of the effect of further improving the visibility, the yellowness of the medical molded product is preferably 3 or less, more preferably 2 or less, and particularly preferably 1.5 or less. The lower the yellowness of the medical molded product, the more preferable it is. Therefore, no lower limit is set and the yellowness is 0 or more.

In the present specification, the whiteness and yellowness of the medical molded article are values measured according to the following method.

(Measuring method of whiteness and yellowness of medical molded products)
A tube having an inner diameter of 3.0 mm and an outer diameter of 4.4 mm is extruded (sample tube). For this sample tube (n = 8), the whiteness (WI) and yellowness (YI) were measured under the following conditions according to a method based on ASTM E313-73, and the average values thereof. Is adopted.

(Polyvinyl chloride resin)
The polyvinyl chloride resin is not particularly limited, and usually, a polyvinyl chloride resin used for medical applications is used in the same manner. Therefore, as the polyvinyl chloride resin, a synthetic product or a commercially available product may be used. Preferably, a polyvinyl chloride resin having a degree of polymerization of about 1000 to 2000 is used. Here, examples of commercially available products include, for example, polyvinyl chloride resins S-400, S1006, S1007, S1008, S1001, S1001N, S1003, S1003N, S1004, KS-1700, KS-2500, KS-3000 (or more, (Made by Kaneka Corporation), etc. The method for synthesizing the polyvinyl chloride resin is not particularly limited, and examples thereof include a suspension polymerization method. The polyvinyl chloride resin may be used alone or in combination of two or more.

(Ester plasticizer)
The polyvinyl chloride resin composition according to the present invention contains an ester plasticizer in an amount of 30 to 160 parts by mass, preferably 40 to 100 parts by mass, based on 100 parts by mass of the polyvinyl chloride resin. Here, if the blending amount of the ester plasticizer exceeds 160 parts by mass, it becomes difficult to uniformly mix the ester plasticizer, which may make it difficult to produce the compound as a polyvinyl chloride resin composition. On the contrary, if the blending amount of the ester plasticizer is less than 30 parts by mass, the compatibility with the polyvinyl chloride resin is lowered and the desired flexibility cannot be obtained, which is not preferable.

Examples of the ester plasticizer are not particularly limited, but for example, trimellitic acid esters such as tri-2-ethylhexyl trimellitic acid (TOTM); tributyl acetyl citrate, trihexyl acetyl citrate, trihexyl n-butyryl citrate and the like. Citrate esters; phthalates such as bis (2-ethylhexyl) phthalate (DEHP) (dioctyl phthalate (DOP)), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), dibutyl phthalate (DBP); Adipate esters such as dioctyl adipate and diisononyl adipate; phosphoric acid esters such as tricresyl phosphate and the like can be mentioned. Among these, from the viewpoints of flexibility (particularly low temperature flexibility), thermal stability, and safety, trimellitic acid ester and phthalate ester are preferable, and TOTM and DEHP are more preferable.

As the ester plasticizer used in the present invention, a synthetic product or a commercially available product may be used. Examples of commercially available products include TOTM-NB manufactured by J-PLUS Co., Ltd. Further, as a synthetic method, for example, a method of mixing and esterifying trimellitic anhydride and an alcohol can be mentioned.

The ester plasticizer may be used alone or in combination of two or more.

(Epoxy plasticizer)
The polyvinyl chloride resin composition according to the present invention contains an epoxy plasticizer in an amount of 5 to 25 parts by mass, preferably 7 to 15 parts by mass, based on 100 parts by mass of the polyvinyl chloride resin. Epoxy plasticizers act as both plasticizers and processing aids. The epoxy plasticizer also acts as a heat stabilizing aid for zinc soap and calcium soap (stabilizer). Here, if the amount of the epoxy plasticizer compounded is too large, there are concerns about deterioration of cytotoxicity and bleeding out of the epoxy plasticizer during molding. On the other hand, if the amount of the epoxy plasticizer blended is too small, the desired flexibility, discoloration resistance, heat resistance may be lowered, or coloring may be induced.

Examples of epoxy plasticizers include epoxies such as epoxidized soybean oil and epoxidized linseed oil.

As the epoxy plasticizer used in the present invention, a synthetic product or a commercially available product may be used. Examples of commercially available products include O-130P and O-180A manufactured by ADEKA CORPORATION. Further, as a synthesis method, for example, a method of directly epoxidizing an alkene can be mentioned.

The epoxy plasticizer may be used alone or in combination of two or more.

(Zinc soap and calcium soap)
In the polyvinyl chloride resin composition according to the present invention, zinc soap and calcium soap are contained in an amount of 0.01 to 0.1 parts by mass as a stabilizer with respect to 100 parts by mass of the polyvinyl chloride resin. It is preferably blended in an amount of 0.03 to 0.08 parts by mass. Here, if the amount is too large, the transparency of the polyvinyl chloride resin composition is lowered. In addition, the coloration of the polyvinyl chloride resin after sterilization tends to increase. On the other hand, if the blending amount is too small, heat resistance and discoloration resistance may be lowered, or coloring may be induced.

The zinc soap is not particularly limited, but one containing a lauryl group, a palmityl group, a stearyl group or an oleyl group such as zinc laurate, zinc palmitate, zinc stearate and zinc oleate is preferably used. Those having such an alkyl group are suitable for medical use from the viewpoint of safety.

As the zinc soap used in the present invention, a synthetic product or a commercially available product may be used. Examples of commercially available products include zinc stearate manufactured by Sakai Chemical Industry Co., Ltd. Further, as a synthesis method for synthesizing zinc soap, for example, a method of making a compound decomposition reaction of an aqueous alkali metal salt solution of a fatty acid and an inorganic metal salt can be mentioned.

The calcium soap is not particularly limited, but like the above zinc soap, it contains a lauryl group, a palmityl group, a stearyl group or an oleyl group such as calcium laurate, calcium palmitate, calcium stearate, or calcium oleate. Is preferably used. Those having such an alkyl group are particularly suitable for medical applications from the viewpoint of safety.

As the calcium soap used in the present invention, a synthetic product or a commercially available product may be used. Examples of commercially available products include calcium stearate manufactured by Sakai Chemical Industry Co., Ltd. Further, as a synthesis method for synthesizing calcium soap, for example, a method of performing a metathesis reaction between an aqueous alkali metal salt solution of a fatty acid and an inorganic metal salt can be mentioned.

The zinc soap and the calcium soap may be used alone or in combination of two or more.

The polyvinyl chloride resin composition according to the present invention includes zinc soap and calcium soap. Here, the mixing ratio of zinc soap and calcium soap is not particularly limited, but the mixing ratio of zinc soap and calcium soap (zinc soap: mass ratio of calcium soap) is preferably 1: 1 to 3, more preferably. Is 1: 1 to 2. With such a mixing ratio, coloring can be significantly reduced, and a medical molded product having a higher whiteness and a lower yellowness can be produced at a lower cost.

The zinc soap and the calcium soap may be separately blended into the polyvinyl chloride resin composition, or may be blended with a premixed mixture in a predetermined ratio. In the latter case, the mixture may be a commercially available product. Examples of commercially available products include stabilizers ADEKA Stub series SC-12, 593, 37, SC-308E (all manufactured by ADEKA CORPORATION) and the like.

(Other ingredients)
The polyvinyl chloride resin composition forming the molded product of the present invention can achieve the object of the present invention and may further contain other optional components as long as the original properties are not particularly impaired. Examples of these optional components include metal oxides, heat resistance improvers, lubricants, pigments, surfactants, processing aids and the like.

Among these, the metal oxide is not particularly limited, and examples thereof include magnesium oxide, calcium oxide, zinc oxide and the like.

The heat resistance improving agent is not particularly limited, and examples thereof include pentaerythritol and hydrotalcite.

The lubricant is not particularly limited, and examples thereof include silicone oil and the like.

The pigment is not particularly limited, and examples thereof include metal complex salt-based pigments.

The surfactant is not particularly limited, and examples thereof include monoglyceride stearate.

The processing aid is not particularly limited, and examples thereof include an acrylic polymer processing aid.

The blending amount of these blending agents is not particularly limited as long as the safety, heat resistance, and coloring resistance of the polyvinyl chloride resin composition are not impaired. Preferably, the total amount of these compounding agents is preferably 0.1 to 0.5 parts by mass with respect to 100 parts by mass of the polyvinyl chloride resin composition according to the present invention.

The polyvinyl chloride resin composition according to the present invention is not particularly limited, and is produced by extrusion-molding the above-mentioned polyvinyl chloride resin composition.

(Extrusion molding method for medical molded products and its equipment)
Next, an extrusion molding method capable of producing a medical molded product having high whiteness and low yellowness even with a small amount of stabilizer, and an extrusion molding apparatus 10 embodying the extrusion molding method. Will be described.

Hereinafter, embodiments will be described with reference to the drawings. The dimensional ratios in the drawings may be exaggerated and differ from the actual ratios for convenience of explanation.

FIG. 1 is a schematic configuration diagram showing an extrusion molding device 10 for a medical molded product according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a main part of the extrusion molding device 10 for a medical molded product shown in FIG. Is.

With reference to FIGS. 1 and 2, the extrusion molding apparatus 10 of the present embodiment extrudes the composition 11 described above, and has a whiteness (WI) of 25 or more and a yellowness (Y). For example, a tube as a medical molded product 12 having an I.) of 3.5 or less is molded. The extrusion molding apparatus 10 uses an extruder 20 in which a screw 21 having a groove 22 formed at the same depth d is rotatably arranged in a barrel 23 and a solid composition 11 formed into the screw 21. Extruded from a feeder 30 that can supply and adjust the supply amount of the composition 11, heaters 41, 42, 43 that apply heat to melt the solid composition 11 supplied to the screw 21, and an extruder 20. It has a die 50 for molding the melted composition 11 into the shape of the medical molded product 12. Then, the feeder 30 adjusts the supply amount of the composition 11 to an amount that does not cause shearing heat generation in the composition 11 in the extruder 20. In the extrusion molding apparatus 10 of this medical molded product, the composition 11 formed in a solid state is transferred to the screw 21 of the extruder 20 having the same depth d of the grooves 22. The composition 11 is supplied in an amount adjusted to an amount that does not cause shearing heat generation. Then, heat from the heaters 41, 42, and 43 is applied to the solid composition 11 supplied to the screw 21 to melt the composition 11, and the melted composition 11 extruded from the extruder 20 is medically molded by the die 50. It is molded into the shape of product 12. The details will be described below.

As described above, the composition 11 contains 30 to 160 parts by mass of the ester plasticizer, 5 to 25 parts by mass of the epoxy plasticizer, and 0.01 to 0 parts by mass of the zinc soap and the calcium soap with respect to 100 parts by mass of the polyvinyl chloride resin. Contains 1 part by mass (total amount). The composition 11 is formed into solid pellets. The pellet 11 (composition) is heat-dried in a dehumidifying dryer (not shown). The pellet 11 is maintained at the moisture content specified by the resin manufacturer under the drying conditions recommended by the resin manufacturer. The pellet 11 has, for example, a spherical shape having a diameter of 3 to 4 mm. The shape of the pellet 11 is not limited to a spherical shape, and may have, for example, a short rod shape.

The extruder 20 has a barrel 23, which is also called a cylinder, a screw 21 that is rotatably held in the barrel 23, and a gear train 24 and a motor 25 that rotationally drive the screw 21. The barrel 23 has an opening for charging a molding material. The screw 21 is formed with a feed zone C1, a transfer zone C2, and a metering zone C3 in this order from the proximal end side to the distal end side. The feed zone C1 of the screw 21 and the portion where the base end portion of the screw 21 faces the inlet of the barrel 23 constitutes the supply portion 26. When a twin-screw extruder is used, although it is easy to plasticize and knead, excessive shear heat is added to the composition 11 and causes burning. Therefore, the extruder 20 is preferably a single-screw extruder.

The screw 21 has a main body portion 21a and a flight portion 21b protruding from the outer peripheral surface of the main body portion 21a. The flight portion 21b extends spirally on the outer peripheral surface of the main body portion 21a. The main body 21a has a straight pipe shape having a constant outer diameter. The flight portion 21b has a constant outer diameter. Therefore, the screw 21 is formed so that the depth d of the groove 22 is the same. The clearance dimension between the feed zone C1 of the screw 21 and the inner peripheral surface of the barrel 23, the clearance dimension between the transfer zone C2 and the inner peripheral surface of the barrel 23, and the gap dimension between the metering zone C3 and the inner peripheral surface of the barrel 23. The gap dimensions are the same for all.

The feeder 30 includes a spare hopper 31 to which the pellet 11 is supplied by a loader (not shown), a main hopper 32 connected to the inlet of the barrel 23 of the extruder 20, and the pellet 11 from the spare hopper 31 to the main hopper 32. It has a transport unit 33 for transporting the above. The transport unit 33 has a tubular body 35 that rotatably holds the feed screw 34, and a motor 36 that rotationally drives the feed screw 34. By rotationally driving the feed screw 34 by the motor 36, the pellets 11 dropped and supplied from the spare hopper 31 are conveyed and supplied into the main hopper 32. The feeder 30 can adjust the supply amount of the composition 11 by adjusting the rotation speed of the feed screw 34.

In addition to the screw type shown in the figure, the transport unit 33 can transport the pellet 11 by applying a coil type, a belt type, a vibration type, an air transport, a piston transport, or another method. In addition to the capacitive metering feeder, a weight metering feeder can also be preferably used for the transport unit 33. The main hopper 32 may be appropriately provided with a decompression unit and an inert gas introduction unit.

Heaters 41, 42, and 43 that apply heat to melt the pellets 11 are provided around the barrel 23. The heaters 41, 42, and 43 are provided corresponding to the feed zone C1, the transfer zone C2, and the metering zone C3 of the screw 21. As the heaters 41, 42, and 43, for example, a band heater which is an electric heater whose temperature can be easily controlled is used. A type of heater that circulates a heat medium can also be used. In order to detect the wall surface temperature of the barrel 23, the tips of the temperature sensors 61, 62, 63 such as a thermocouple are embedded in the wall surface of the barrel 23. The tip portions of the temperature sensors 61, 62, and 63 can be attached in close contact with the surface of the barrel 23. By controlling the energization of the band heaters 41, 42, and 43 on and off, the wall surface temperature of the barrel 23 is maintained at the set temperature. The set temperature varies depending on the degree of polymerization of the material contained in the composition 11, the type of plasticizer and the amount added, and is, for example, 160 to 170 ° C.

The die 50 is formed with a passage through which the melted composition 11 extruded from the extruder 20 passes. The opening shape of the tip of the die 50 has a shape that matches the shape of the medical molded product 12. The base end of the die 50 is connected to the tip of the extruder 20.

Die heaters 44 and 45 that apply heat to the melted composition 11 extruded from the extruder 20 are also provided at the base end and the tip end of the die 50. Similar to the heaters 41, 42, 43 provided on the barrel 23, the band heaters are also used for the die heaters 44, 45. In order to detect the wall surface temperature of the die 50, the tips of the temperature sensors 64 and 65 such as thermocouples are embedded in the wall surface of the die 50. It is also possible to attach the tips of the temperature sensors 64 and 65 in close contact with the surface of the die 50. By controlling the energization of the band heaters 44 and 45 on and off, the wall surface temperature of the die 50 is maintained at the set temperature. The set temperature is, for example, 160 to 170 ° C.

The extrusion molding apparatus 10 further includes a controller 70 that controls the operation of the extruder 20 and the feeder 30. The operation of the feeder 30 is controlled by the controller 70, and the supply amount of the solid composition 11 is adjusted to an amount that does not cause shearing heat generation in the composition 11 in the extruder 20. The operation of the extruder 20 is controlled by the controller 70, and the rotation speed of the screw 21 is adjusted.

In the present embodiment, the screw 21 in which the depth d of the groove 22 is formed to be the same is used. Further, the feeder 30 adjusts the rotation speed of the feed screw 34 so that the composition 11 formed in a solid state is supplied in an amount adjusted so as not to cause shearing heat generation in the composition 11 in the extruder 20. We are supplying. Therefore, it is possible to prevent the composition 11 from staying in the extruder 20, and further prevent the composition 11 from being excessively sheared and generated in the extruder 20. Therefore, it is possible to suppress two factors that cause burning of the molded product.

Here, the "amount that does not cause shearing heat generation in the composition 11 in the extruder 20" is defined by determining the supply amount of the composition 11 in relation to the depth d of the groove 22 of the screw 21. It means an amount capable of suppressing the retention of the composition 11 in the extruder 20 and further suppressing excessive shearing heat generation of the composition 11 in the extruder 20 ". Therefore, even if the composition 11 generates some shearing heat, the "amount of some shearing heat generated in the composition 11" is "extruded" as long as the excessive shearing heat that causes burning is not generated. It must be understood that it is included in "amount that does not cause shearing heat generation in the composition 11 in the machine 20".

From the viewpoint of suppressing excessive shearing heat generation of the composition 11 in the extruder 20, the temperature of the composition 11 in the extruder 20 is "set temperature + 5 ° C. or lower", more preferably "set temperature + 2 ° C. or lower". It is preferable to control the supply amount of the composition 11 by the feeder 30 so as to be. This is because excessive shearing heat generation, which causes burning of the molded product, can be reliably suppressed. The temperature of the composition 11 in the extruder 20 can be easily confirmed by the temperature sensors 61, 62, 63.

Next, the action will be described.

First, with respect to 100 parts by mass of the polyvinyl chloride resin, 30 to 160 parts by mass of the ester plasticizer, 5 to 25 parts by mass of the epoxy plasticizer, and 0.01 to 0.1 parts by mass of zinc soap and calcium soap (total amount). The composition 11 containing the above is formed into solid pellets 11.

By controlling the energization of the heaters 41, 42, 43 and the die heaters 44, 45 on and off, the wall temperature of the barrel 23 and the wall temperature of the die 50 are raised to the set temperature.

The feeder 30 supplies the pellet 11 to the screw 21 of the extruder 20 in which the depth d of the groove 22 is formed to be the same. At this time, the feeder 30 supplies the pellets 11 in the extruder 20 in an amount adjusted so as not to cause shearing heat generation in the composition 11 by adjusting the rotation speed of the feed screw 34.

The pellet 11 supplied to the screw 21 is melted by applying heat from the heaters 41, 42, and 43. When the melted composition 11 reaches the tip of the screw 21 through the groove 22 of the screw 21, the guiding force by the groove 22 is lost, so that the forward force is weakened. Since the advance of the melted composition 11 is suppressed, the pressure of the melted composition 11 becomes slightly higher in the metering zone C3. However, this increase in pressure does not cause shearing heat generation in the composition 11.

Then, the melted composition 11 extruded from the extruder 20 is molded into the shape of the medical molded product 12 by the die 50. During extrusion molding, the wall temperature of the barrel 23 and the wall temperature of the die 50 are maintained at the set temperature by controlling the energization of the heaters 41, 42, 43 and the die heaters 44, 45 on and off.

As described above, according to the extrusion molding technique for the medical molded product of the present embodiment, the screw 21 having the groove 22 formed at the same depth d is used, and the composition is further formed into a solid state. The product 11 is supplied in the extruder 20 in an amount adjusted to an amount that does not cause shearing heat generation in the composition 11. Therefore, it is possible to prevent the composition 11 from staying in the extruder 20, and further prevent the composition 11 from being excessively sheared and generated in the extruder 20. As a result of being able to suppress two factors that cause burning of the molded product, a medical molded product 12 having a low degree of coloring (high whiteness and low yellowness) can be manufactured at low cost even with a small amount of metal soap. it can.

The temperature of the composition 11 in the extruder 20 is set to "set temperature + 5 ° C. or lower". With this configuration, excessive shear heat generation that causes burning of the molded product is surely suppressed, and even a small amount of metal soap has a low degree of coloring (high whiteness and low yellowness). ) The medical molded product 12 can be manufactured at low cost.

Although the extrusion molding apparatus 10 for molding a tube as a medical molded product 12 has been described, the present invention is not limited to this case. The extrusion molding apparatus 10 can be appropriately modified and applied in order to mold medical molded products for various purposes such as infusions, bags for blood transfusions, and tubes connected to these bags.

The effects of the present invention will be described with reference to the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. In the following examples, the operation was performed at room temperature (25 ° C.) unless otherwise specified. Unless otherwise specified, "%" and "parts" mean "mass%" and "parts by mass", respectively.

Example 1
Polyvinyl chloride resin (Kaneka Co., Ltd., KS-1700, average degree of polymerization: 1700) 100 kg, bis (2-ethylhexyl) phthalate (DEHP) 52 kg as an ester plasticizer, epoxidized soybean oil as an epoxy plasticizer (Co., Ltd.) Made by ADEKA, O-130P) 8 kg, Ca-Zn-based stabilizer as a stabilizer (manufactured by ADEKA Co., Ltd., trade name: Adecastab 37, calcium stearate content: about 7.57% by mass, zinc stearate content: about 10. 1% by mass) 0.07 kg and 0.15 kg of silicone oil (Shin-Etsu Chemical Co., Ltd. trade name: KF-50) were mixed to prepare a polyvinyl chloride resin composition. In this polyvinyl chloride resin composition, 0.0053 kg and 0.00707 kg of calcium stearate and 0.00707 kg of zinc stearate are contained, respectively.

Next, this polyvinyl chloride resin composition is formed into pellets, and a tube having an inner diameter of φ3.0 mm and an outer diameter of φ4.4 mm is extruded using the above-mentioned extrusion molding device for a medical molded product. did. The pellet used had a spherical shape with a diameter of 3 to 4 mm, and the supply amount was set to 4 kg / hr. The inner diameter of the barrel of the extruder is φ22 mm. The rotation speed of the screw was set to 50 rpm. In the extrusion molding apparatus, pellets were supplied to the screw of the extruder formed to have the same groove depth in a supply amount adjusted to an amount that does not cause shear heat generation in the composition in the extruder. Then, heat from a heater was applied to the pellets supplied to the screw to melt the pellet, and the melted composition extruded from the extruder was formed into a tube shape by a die. The set temperature of the heater was 160 ° C. for the heater 41 and 170 ° C. for the heaters 42 to 45.

The whiteness and yellowness of the obtained tubes were measured and found to be 25.8 and 2.5, respectively. From this result, it can be seen that the tubes of this example show high whiteness and low yellowness even with a small amount of stabilizer (zinc soap and calcium soap).

Example 2
In Example 1, a tube was produced in the same manner as in Example 1 except that the blending amount of the Ca—Zn-based stabilizer (manufactured by ADEKA Corporation, trade name: ADEKA STAB 37) was changed to 0.21 kg.

The whiteness and yellowness of the obtained tubes were measured and found to be 28.4 and 1.1, respectively. From this result, it can be seen that the tubes of this example show high whiteness and low yellowness even with a small amount of stabilizer (zinc soap and calcium soap).

Example 3
In Example 1, a tube was produced in the same manner as in Example 1 except that the blending amount of the Ca—Zn-based stabilizer (manufactured by ADEKA Corporation, trade name: ADEKA STAB 37) was changed to 0.35 kg.

The whiteness and yellowness of the obtained tubes were measured and found to be 28.0 and 1.2, respectively. From this result, it can be seen that the tubes of this example show high whiteness and low yellowness even with a small amount of stabilizer (zinc soap and calcium soap).

Example 4
In Example 1, a tube was produced in the same manner as in Example 1 except that the blending amount of the Ca—Zn-based stabilizer (manufactured by ADEKA Corporation, trade name: ADEKA STAB 37) was changed to 0.70 kg.

The whiteness and yellowness of the obtained tubes were measured and found to be 27.6 and 0.8, respectively. From this result, it can be seen that the tubes of this example show high whiteness and low yellowness even with a small amount of stabilizer (zinc soap and calcium soap).

This application is based on Japanese Patent Application No. 2015-064449 filed on March 26, 2015, the disclosure of which is referenced and incorporated as a whole.

10 Extrusion molding equipment for medical molded products,
11 pellets (composition),
12 tubes (medical molded products),
20 extruder,
21 screw,
22 grooves,
23 barrels,
30 feeder,
34 feed screw,
41, 42, 43 heaters,
44, 45 die heaters,
50 dies,
61, 62, 63 temperature sensor,
64, 65 temperature sensor,
70 controller,
C1 feed zone,
C2 transfer zone,
C3 metering zone,
d Groove depth.

Claims (9)

For 100 parts by mass of polyvinyl chloride resin
Ester plasticizer 30-160 parts by mass,
Epoxy plasticizer 5 to 25 parts by mass, and zinc soap and calcium soap 0.01 to 0.1 parts by mass (total amount)
The composition containing is extruded and
A medical molded article having a whiteness (WI) of 25 or more and a yellowness (YI) of 3.5 or less. A medical product in which the composition according to claim 1 is extruded to form a medical molded product having a whiteness (WI) of 25 or more and a yellowness (YI) of 3.5 or less. This is an extrusion molding method for molded products.
The composition formed in a solid state is supplied to the screw of an extruder formed to have the same groove depth in a supply amount adjusted to an amount that does not cause shearing heat generation in the composition in the extruder. And
The solid composition supplied to the screw is melted by applying heat from a heater.
A method for extrusion molding of a medical molded product, in which the melted composition extruded from the extruder is molded into the shape of a medical molded product by a die. The extrusion molding method for a medical molded product according to claim 2, wherein the temperature of the composition in the extruder is "set temperature + 5 ° C." or less. The extrusion molding method for a medical molded product according to claim 2 or 3, wherein the medical molded product is a bag for infusion, a bag for blood transfusion, or a tube. A medical product in which the composition according to claim 1 is extruded to form a medical molded product having a whiteness (WI) of 25 or more and a yellowness (YI) of 3.5 or less. Extrusion molding equipment for molded products
An extruder in which screws formed to have the same groove depth are rotatably arranged in a barrel, and
A feeder in which the composition formed in a solid state is supplied to the screw and the supply amount of the composition can be adjusted.
A heater that applies heat to melt the solid composition supplied to the screw, and
It has a die for molding the melted composition extruded from the extruder into the shape of a medical molded article.
The feeder is an extrusion molding device for a medical molded product that adjusts the supply amount of the composition to an amount that does not cause shear heat generation in the composition in the extruder. The extrusion molding apparatus for a medical molded product according to claim 5, wherein the temperature of the composition is "set temperature + 5 ° C." or less in the extruder. The extrusion molding apparatus for a medical molded product according to claim 5 or 6, further comprising a die heater for applying heat to the composition in a molten state extruded from the extruder. The extrusion molding apparatus for a medical molded product according to any one of claims 5 to 7, wherein the medical molded product is a bag for infusion, a bag for blood transfusion, or a tube. For 100 parts by mass of polyvinyl chloride resin
Ester plasticizer 30-160 parts by mass,
Epoxy plasticizer 5-25 parts by mass, and
Zinc soap and calcium soap 0.01-0.1 parts by mass (total amount)
It is a medical molded product produced by an extrusion molding method for extrusion molding a composition containing the above.
The extrusion molding method
The composition formed in a solid state is supplied to the screw of an extruder formed to have the same groove depth in a supply amount adjusted to an amount that does not cause shearing heat generation in the composition in the extruder. And
The solid composition supplied to the screw is melted by applying heat from a heater.
The melted composition extruded from the extruder is molded into the shape of a medical molded article by a die, having a whiteness (WI) of 25 or more and a yellowness (YI). A medical molded article having a value of 3.5 or less.