WO2021053799A1

WO2021053799A1 - Nozzle

Info

Publication number: WO2021053799A1
Application number: PCT/JP2019/036804
Authority: WO
Inventors: 丈太郎長尾; 耕太岡本; 正毅青谷; 隆司大貫; 正弘國則; 諭男木村; 岩崎　力
Original assignee: 東洋製罐グループホールディングス株式会社
Priority date: 2019-09-19
Filing date: 2019-09-19
Publication date: 2021-03-25

Abstract

The present invention provides a nozzle which not only has excellent liquid repellency for the outer surface as well as the inner surface which serves as a liquid flow path but can be readily manufactured, is attachable to and detachable from a device, and can be used for dispensing, measuring, dripping, or spraying a liquid. In addition, the nozzle is characterized by comprising a blend obtained by mixing a fluorine-containing polymer in a base material polymer.

Description

nozzle

The present invention relates to nozzles, especially pipette tips.

In many chemical experiments and tests, a pipette is used to collect the sample liquid and drop it into a petri dish. Such pipettes are used for collecting and dropping various sample liquids, from low-viscosity liquids such as pure water and physiological saline to high-viscosity liquids such as blood and urine, in order to prevent contamination. , Needs to be washed frequently.
In order to avoid such cleaning work, pipette tips that are detachably attached to the device are now widely used.

The pipette tip is molded from an olefin resin such as polypropylene or a styrene resin such as polystyrene because of its excellent chemical resistance, but the solution is repeatedly collected and dropped from pure water or physiological saline. Then, the sample liquid easily adheres to the outer surface due to the liquid circulation at the tip of the chip, and the quantitativeness of the amount of the liquid to be dropped is lowered. Therefore, it is disposable every time, which is extremely uneconomical.
Further, with a highly viscous liquid such as blood or urine, there is a problem that the dropping speed becomes slow, the test work takes time, and the liquid tends to remain in the chip.

Patent Document 1 proposes a pipette tip that solves the above problems. This pipette tip is made of a polypropylene tip coated with a water repellent treatment agent. Such a pipette tip has high liquid repellency for various sample liquids due to the water repellent treatment agent, and particularly has high liquid repellency on the outer surface of the tip. Can be done.

However, the pipette tip needs further improvement in order to improve the liquid repellency inside the tip. That is, since this pipette tip is coated with a water repellent treatment agent, the coating inside the tip cannot be effectively performed. The liquid flow path formed in the pipette tip has a very small diameter, for example, the tip. This is because the diameter of the liquid flow path at the tip (inner diameter of the chip) is 1 mm or less, so that the coating liquid of the water repellent treatment agent cannot be effectively coated inside the chip by means of coating or dipping. For this reason, the liquid repellency of the liquid flow path inside the chip is particularly unsatisfactory, and when a highly viscous liquid is used as the sample liquid, liquid residue is likely to occur inside the chip, the discharge speed is slow, and workability is low. The problem remains.
Further, in order to uniformly form the coating film of the water repellent treatment agent, it is necessary to apply the coating liquid, remove the excess liquid by wiping, and then heat-dry it, which causes a problem that the productivity is extremely low. There is also.

Patent No. 5129729

Therefore, an object of the present invention is to provide a nozzle, particularly a pipette tip, which is not only excellent in liquid repellency on the inner surface serving as a liquid flow path in addition to the outer surface, but also can be easily manufactured. ..

According to the present invention, the resin nozzle is removable to the apparatus and is used for dispensing, measuring, dropping, or spraying a liquid, and the resin nozzle is a base polymer mixed with a fluoropolymer. Nozzles made of blends are provided.

In the nozzle of the present invention
(1) The outer and inner surfaces of the nozzle are superhydrophobic surfaces with a water contact angle of 105 degrees or more.
(2) The outer and inner surfaces of the nozzle are rough surfaces.
(3) The rough surface is a rough surface having a rectangular uneven structure, and when water droplets are dropped on the rough surface, the area ratio φS of the water droplets represented by the projected area of the solid-liquid interface per unit area is 0. Must be in the range of .05 to 0.8,
(4) When the arithmetic average roughness corresponding to the amplitude of the uneven structure forming the rough surface is Ra and the average length corresponding to 1/2 pitch of the uneven structure is RSm, the rough surface is Ra / Satisfying RSm ≧ 50 × 10 ^-3,
(5) The fluoropolymer is a fluoroacrylic resin or a fluorosilicone resin.
(6) The base polymer is an olefin resin or a styrene resin.
(7) The blend contains a fluoropolymer in an amount of 0.01 to 50 parts by mass per 100 parts by mass of the base polymer.
(8) The nozzle is a pipette tip.
Is preferable.

In the resin nozzle of the present invention, an agent for improving liquid repellency, that is, a fluoropolymer is blended in the resin forming the nozzle. That is, by molding using this blend, specifically, injection molding, liquid repellency is effectively imparted not only to the outer surface of the nozzle but also to the inner surface which is the surface of the liquid flow path, and the coating liquid is used for coating. No special treatment such as drying or drying is required. Therefore, this nozzle, for example, a pipette tip, can be efficiently manufactured, the variation among products is suppressed, and the productivity is extremely high.

As described above, since both the outer surface and the inner surface of the nozzle of the present invention are liquid-repellent, when the liquid is repeatedly collected and dropped for a low-viscosity liquid such as pure water or physiological saline, the nozzle is used. It is possible to effectively prevent the tip of the pouring path from adhering to the outer surface due to the liquid circulation, ensure the quantitativeness of the amount of liquid to be dropped, and perform repeated tests. Further, for highly viscous liquids such as blood and urine, the dropping speed is increased, which improves the workability of various measurements and tests, and further prevents the liquid from remaining in the nozzle.

Further, in the nozzle of the present invention, the surface distribution amount of the fluorine-containing functional group can be increased and the liquid repellency can be further improved by the heat treatment (migration treatment) after molding. Further, by molding the nozzle by injection molding using a molding die having a roughened surface, the inner and outer surfaces of the nozzle in which the fluorine-containing functional groups are distributed can be roughened. The liquid repellency can be further improved by the above.

A side sectional view showing the form of the pipette tip of the present invention.

With reference to FIG. 1, the pipette tip 1 which is a typical example of the nozzle of the present invention is a tubular body having a large diameter at the upper side and a tapered shape at the lower side as a whole, and the internal space is a liquid. It is a flow path 3. That is, the tip of the pipette is fitted into the upper end of the liquid flow path 3 of the pipette tip 1, the sample liquid is collected from the tip (lower end) of the tip 1, and the collected sample liquid is dropped onto a predetermined test site. is there.

Such a pipette tip 1 is used having an appropriate lower end inner diameter (diameter at the lower end of the liquid flow path 3) according to the amount of the sample liquid to be collected, the amount of dropping, and the like. The inner diameter of the lower end is as small as 1 mm or less. Further, the inner diameter of the upper end of the liquid flow path 3 has a size capable of fitting and fixing the lower end of the pipette.

In the present invention, the pipette tip 1 is formed by using a blend of a base polymer and a fluoropolymer. Specifically, the pipette tip 1 of the present invention can be obtained by injection molding using the blend.

In such a blend, the fluoropolymer is an agent for improving the liquid repellency. Examples of such fluoropolymers include polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), perfluoroalkoxyfluororesin (PFA), and four. Ethylene fluoride / propylene hexafluoride copolymer (FEP), ethylene / ethylene tetrafluoride copolymer (ETFE), ethylene / chlorotrifouroethylene copolymer (ECTFE), etc. can be used. In the present invention, a fluoroacrylic resin, a fluorosilicone resin, or the like is suitable because it can exhibit injection molding and high liquid repellency.

The above-mentioned fluorine-containing acrylic resin is described by, for example, the following formula:
_{_{Rf-CH 2 -CH 2 -OCO- (}} CX) = CH 2
In the formula, Rf is a fluorine-containing alkyl group such as a perfluoroalkyl group.
X is an alkyl group such as a hydrogen atom or a methyl group,
It is a fluorine-containing acrylic resin represented by, and a polymer obtained by polymerizing the resin is suitable.

Further, the fluorine-containing silicone resin is, for example, the following formula:
(RO) ₂ RfSiO- (RORfSiO) n-SiRf (OR) ₂
In the formula, R is an alkyl group such as a hydrogen atom or a methyl group.
Rf is a fluorine-containing group such as a fluoroalkyl group, and is
n is a number indicating the degree of polymerization,
It is a polyorganosiloxane represented by.

In the present invention, as the above-mentioned fluoropolymer, it is generally said that a fluoropolymer having a molecular weight of less than C8 telomer is suitable from the viewpoint of safety.

The base polymer to which the above fluorine-containing polymer is blended is a fluorine-free resin, and either a thermoplastic resin or a thermosetting resin can be used, but it is thermoplastic especially from the viewpoint of injection moldability. Resin is suitable.
Examples of such thermoplastic resins include low-density polyethylene, high-density polyethylene, polypropylene, poly1-butene, poly4-methyl-1-pentene, ethylene, propylene, 1-butene, 4-methyl-1-pentene and the like. Olefin resins such as random or block copolymers of α-olefins and cyclic olefin copolymers; ethylene / vinyl acetate copolymers, ethylene / vinyl alcohol copolymers, ethylene / vinyl chloride copolymers and the like. Vinyl-based copolymers; styrene-based resins such as polystyrene, acrylonitrile / styrene copolymers, ABS, α-methylstyrene / styrene copolymers; polyvinyl chloride, polyvinylidene chloride, vinyl chloride / vinylidene chloride copolymers, poly Vinyl resins such as methyl acrylate and polymethyl methacrylate; polyamide resins such as nylon 6, nylon 6-6, nylon 6-10, nylon 11, and nylon 12; polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. , And polyester resins such as these copolymerized polyesters; polycarbonate resins; polyphenylene oxide resins; biodegradable resins such as polylactic acid; etc., all of which have an injection grade melt flow rate. Will be done.

In the present invention, among the above-mentioned thermoplastic resins, olefin resins and styrene resins are preferable, and polypropylene and polystyrene are particularly preferable, from the viewpoint of chemical resistance and the like particularly required for nozzles such as pipette tips. ..

Further, in the present invention, the blend of the base polymer and the fluororesin is a fluoropolymer in an amount of 0.01 to 50 parts by mass, particularly 0.05 to 10 parts by mass per 100 parts by mass of the base polymer. Is preferably blended. Even if the amount of the fluoropolymer compounded is larger than necessary, the liquid repellency is not further improved, but rather the injection moldability tends to be difficult. Further, when the blending amount of the fluoropolymer is small, it becomes difficult to secure sufficient liquid repellency.

The pipette tip 1 of the present invention is injection-molded using a blend obtained by melt-kneading the above-mentioned base polymer and the fluoropolymer, that is, the blend is shaped into the shape of the pipette tip 1. It can be easily obtained by injecting and filling the cavity of the injection mold for cooling and cooling. Alternatively, compression molding may be used instead of injection molding.

Since the fluoropolymer contained in the pipette tip 1 of the present invention thus obtained is distributed throughout the pipette tip 1, the fluoropolymer is contained not only on the outer surface 1a but also on the inner surface 1b, that is, the surface of the liquid flow path 3. The liquid repellency of the polymer is exhibited. Therefore, when a low-viscosity liquid such as pure water or physiological saline is repeatedly collected and dropped, the liquid drainage is high, so that the liquid adheres effectively to the outer surface 1a of the tip of the tip due to the liquid circulation. This is prevented, the quantitativeness of the amount of liquid to be dropped can be ensured, and pipetting can be repeated many times without exchanging the tip 1. Further, for highly viscous liquids such as blood and urine, since the inner surface 1b exhibits high liquid repellency, the dropping speed of such highly viscous liquids is high, and the workability of various measurements and tests is improved, and further. Is also effective in preventing liquid residue in the chip 1.

As described above, in the present invention, since the fluoropolymer that exhibits liquid repellency is blended in the molding material of the pipette tip 1, it is possible to impart liquid repellency to both the outer surface 1a and the inner surface 1b. it can. For example, when the liquid repellent treatment agent is applied to the surface of the pipette tip 1 by coating, the inner diameter of the tip of the tip 1 is very small, so that it is very difficult to coat the inner surface 1b with the treatment agent. Even if the inner surface 1b can be coated, a means such as removing excess coating liquid or further heating to volatilize the solvent is required, and the productivity is extremely low.
However, in the present invention, the liquid repellency can be imparted to both the outer surface 1a and the inner surface 1b only by injection molding according to a conventional method, so that the productivity is extremely high.

Further, in the present invention, the liquid repellency can be further enhanced by molding the pipette tip 1 by injection molding using the above-mentioned blend and then performing a migration treatment, for example, 23 ° C. It is possible to form a water-repellent surface having a water contact angle of 105 degrees or more.

This migration process is performed by holding at least the outer surface 1a and the inner surface 1b of the pipette tip 1 at a temperature of 30 ° C. or higher and lower than 160 ° C. for 1 second or longer. If the migration treatment is performed at a temperature of 160 ° C. or higher, the molded pipette tip 1 is deformed, so that the heating temperature must be a temperature equal to or lower than the melting point of the base polymer or the fluoropolymer.

By such a migration treatment (heat treatment), the fluoropolymer having a low surface free energy distributed in the base polymer is migrated to the surface side, which further improves the liquid repellency. is there. For example, by such a migration treatment, a concentration gradient of fluorine atoms is formed, the concentration of fluorine atoms on the surface side (outer surface 1a and inner surface 1b) is high, and the concentration of fluorine atoms inside is low.

If the migration treatment as described above is performed at a temperature lower than the above temperature, the migration of the fluoropolymer becomes insufficient, sufficient improvement in liquid repellency is not exhibited, and it is assumed that the liquid repellency can be improved. However, it takes an extremely long time and cannot be industrially adopted.

Further, the above migration process can be performed by storage in a heating furnace, high frequency heating, hot air heating, infrared radiant heating such as laser, etc., but only the outer surface 1a or inner surface 1b side of the pipette tip 1 is selectively heated. It is also possible to improve the liquid repellency of only one surface side. For example, if the use of the pipette tip 1 is limited to inspections and measurements on highly viscous liquids, only the inner surface 1b side can be heated to improve liquid repellency and inspections on low viscosity liquids. And if limited to measurement, the outer surface 1a side can be selectively heated to improve the liquid repellency.

Further, in the present invention, the outer surface 1a and the inner surface 1b of the pipette tip 1 obtained by making the surface of the molding die used for injection molding rough by blasting, etching or the like are made rough. By such roughening, the slipperiness to the sample liquid can be improved, the dropping speed can be increased, and the liquid adhesion can be prevented more effectively.
That is, by making such a rough surface, a fine air layer is interposed between the sample liquid and the surface on which the fluoropolymer is distributed, and the presence of such an air layer causes slipperiness with respect to the sample liquid. Is significantly improved.

The degree of roughening described above is, for example, that the outer surface 1a or inner surface 1b of the pipette tip 1 is a rough surface having a rectangular uneven structure, and when water droplets are dropped on the rough surface, the solid-liquid interface per unit area The area ratio φS of the water droplet represented by the projected area is in the range of 0.05 to 0.8, or the arithmetic mean roughness corresponding to the amplitude of the uneven structure forming the rough surface is Ra. When the average length corresponding to the 1/2 pitch of the uneven structure is RSm, it is sufficient that the ^{rough surface is Ra / RSm ≧ 50 × 10 -3.}

Since the pipette tip of the present invention exhibits excellent liquid repellency on both the outer surface and the inner surface, it effectively prevents the adhesion of the sample liquid and can be used repeatedly many times, which is extremely economical. Furthermore, it is possible to increase the dropping speed of highly viscous liquids and improve the work efficiency of various measurements and inspections.
Further, the liquid repellency can be further improved without any special means such as coating, and the productivity is extremely excellent.
Further, various additives such as an antioxidant, a colorant, and an antioxidant can be blended in the blend of the base polymer and the fluoropolymer that forms the pipette tip of the present invention. Since the additive may cause contamination and further reduce the migration property of the fluoropolymer, it is optimal that this blend is a two-component system of a base polymer and a fluoropolymer. is there.

Examples of the nozzle of the present invention other than the pipette tip include a nozzle for a liquid dropping device (eg, Kasai Seisakusho Co., Ltd.) that drops water, oil, chemicals, solvent, etc. by gravity type or dispenser type, and metal processing. Examples thereof include a hose nozzle (eg, Misumi Co., Ltd.) used when applying a lubricating oil such as a coolant used in a machine or the like. The nozzle is not limited to this, as long as it is a nozzle used for dropping or pouring a liquid. The present invention is suitably applied to a nozzle having a particularly narrow pouring path and a form in which work such as coating is difficult.

1: Pipette tip 1a: Outer surface 1b: Inner surface 3: Liquid flow path

Claims

A resin nozzle that can be attached to and detached from the device and is used for dispensing, measuring, dropping, or spraying liquid, and the resin nozzle is a nozzle made of a blend of a base polymer and a fluoropolymer.
The nozzle according to claim 1, wherein the outer surface and the inner surface of the nozzle are water-repellent surfaces having a water contact angle of 105 degrees or more.
The nozzle according to claim 1, wherein the outer surface and the inner surface of the nozzle are rough surfaces.
The rough surface is a rough surface having a rectangular uneven structure, and when water droplets are dropped on the rough surface, the area ratio φS of the water droplets represented by the projected area of the solid-liquid interface per unit area is 0.05 to. The nozzle according to claim 3, which is in the range of 0.8.
When the arithmetic average roughness corresponding to the amplitude of the uneven structure forming the rough surface is Ra and the average length corresponding to 1/2 pitch of the uneven structure is RSm, the rough surface is Ra / RSm ≧ 50. The nozzle according to claim 3, which satisfies × 10 -3.
The nozzle according to claim 1, wherein the fluoropolymer is a fluoroacrylic resin or a fluorosilicone resin.
The nozzle according to claim 1, wherein the base polymer is an olefin resin or a styrene resin.
The nozzle according to claim 1, wherein the blend contains a fluoropolymer in an amount of 0.01 to 50 parts by mass per 100 parts by mass of the base polymer.
The nozzle according to claim 1, which is a pipette tip.