JPH11333900A - Manufacture of plastic member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the possibility of elution of aromatic and olefinic substances into a liquid in contact with a plastic member, by using as a dispersion a single solution having high volatility and containing no aromatic nor olefinic substance. SOLUTION: A plastic member is manufactured by a method wherein a particulate plastic base is made paste by adding a dispersion thereto and mixing it therewith, extruded in the shape of a tube, a film or a membrane by an extruder and fired at a high temperature. As to the plastic base, a fluorine-series substance such as polytetrafluoroethylene which passes vapor alone and checks permeation of liquid is used. As for the dispersion, a single solution of a straight-chain paraffinic substance or the like which has high volatility and contains no aromatic nor olefinic substance, e.g. unsaturated hydrocarbon, is used. According to this constitution, no aromatic nor olefinic substance exists in the manufactured plastic member and the possibility that these two substances are liberated and eluted into liquid at the time when the liquid comes into contact with the member can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a plastic member by adding a dispersion liquid to a particulate plastic base material, forming a paste, extruding the paste, and firing at a high temperature. Manufacture of plastic parts suitable for use in degassing equipment for removing dissolved gases from liquids (medium) in various physics / analysis equipment including graphs, various production process equipment including pharmaceuticals, semiconductors, liquid crystals, etc. It is about the method.

[0002]

2. Description of the Related Art For example, in a liquid chromatograph apparatus, a degassing apparatus is used to remove (degas) a dissolved gas from a sample solution, a solvent, a buffer, or the like. Fluorine-based plastic members that allow only gas to pass through and prevent liquid permeation at the parts that come into contact with solvents, buffers, etc., specifically, tubes, films, and membranes made of polytetrafluoroethylene (PTFE) are used. You.

[0003] Polytetrafluoroethylene (PTFE) tubes, films and membranes used in this type of degassing apparatus are usually prepared by adding a gasoline fraction (naphtha, white oil, etc.) to powdered polytetrafluoroethylene. Add and mix to form a paste, extrude it and heat it to
To 400 ° C.). At that time, a low-boiling liquid such as the gasoline fraction is to be evaporated and removed during firing. However, in practice, low-boiling liquids, especially aromatic and olefinic substances, do not completely evaporate and remain in small quantities in plastic parts. The substances remaining in these plastic members are released and eluted into the liquid when the liquid comes into contact with the plastic members, and adversely affect the measurement results of liquid chromatographs and the like and the quality maintenance management in various production processes (such as measurement errors). ).

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional problems, and has an adverse effect on the measurement results of a liquid chromatograph or the like and the quality maintenance management in various production processes. It is an object of the present invention to provide a method for producing a plastic member in which the group-based substance and the olefin-based substance do not elute into a liquid in contact with the plastic member.

[0005]

According to the present invention, there is provided a method for producing a plastic member, comprising the steps of: adding a dispersion liquid to a particulate plastic base material to form a paste; In which a plastic member is produced by extruding and baking at a high temperature, characterized in that a single solution having high volatility and containing no aromatic substance and no olefin substance is used as the dispersion. As a preferred embodiment of the present invention, as the dispersion liquid, a single solution containing no volatile hydrocarbon-containing linear paraffinic material having good volatility and containing no aromatic and olefinic materials, and Polytetrafluoroethylene (PTFE) is used as the plastic substrate.

[0006]

Next, preferred embodiments of the present invention will be described in detail. The plastic member according to the present invention is formed by adding and mixing a dispersion liquid to a particulate plastic base material to form a paste, and extruding the pasted plastic base material into a tube shape or a film shape or a film shape by an extruder, It is manufactured by firing at high temperature. In the present specification, the expression “particulate” includes:
It also includes those in the form of fine particles.

As the plastic substrate applicable to the present invention, a fluorine-based plastic substrate that allows only gas to pass and prevents liquid from permeating, specifically, polytetrafluoroethylene (PTFE) or fluorinated ethylene propylene ( F
EP), ethylene tetrafluoroethylene (ETFE)
And the like, but the present invention is not limited to these polymers.

[0008] As a dispersion to be added to and mixed with the particulate plastic substrate, a single solution having high volatility and containing no aromatic or olefinic substance is used. Specifically, a single solution having high volatility, such as a linear paraffinic substance containing no unsaturated hydrocarbon and containing no aromatic substance and olefinic substance, is used as the dispersion liquid.

Thus, polytetrafluoroethylene (hereinafter abbreviated as PTFE) is used as a plastic base material, and a linear paraffinic material containing no unsaturated hydrocarbon is used as a dispersion liquid. The dispersion was added and mixed to prepare a paste-like PTFE. This paste-like PTFE was extruded into a tube by an extruder and fired to obtain a PTFE tube. The PTFE tube obtained above is incorporated in a vacuum deaerator for previously removing (degassing) a gas from a sample liquid, a solvent, a buffer, or the like in a liquid chromatograph, and is detected by gradient elution liquid chromatography. did. By the way, in the gradient elution liquid chromatography, the concentration of the mobile phase (solvent) changes continuously during the chromatographic operation, and contaminants released in the mobile phase are concentrated during the gradient elution in the separation column. Elute with the proportion of the corresponding eluent in the gradient. Therefore, for example, when an aromatic substance having ultraviolet absorption enters the detector (ultraviolet absorption detector), it interferes with the measurement.

FIG. 1 shows a chromatogram detected by gradient elution liquid chromatography, which was obtained from a liquid chromatograph in which a PTFE tube manufactured by a conventional method was incorporated in a vacuum deaerator. Are obtained from a liquid chromatograph in which the PTFE tube manufactured by the method of the above embodiment is incorporated in a vacuum deaerator. For detection, an acetonitrile-water mixture was used, and an ultraviolet absorption detector having a wavelength of 210 nm was used as a detector. As is clear from FIG. 1, in the PTFE tube manufactured by the conventional method, contamination causing an adverse effect (error) on the measurement result in the liquid chromatograph has occurred, whereas the method of Example 1 of the present invention has been described. It is understood that the PTFE tubing produced by the above-mentioned method exhibits a substantially flat baseline, and there is almost no interference in the quantitative measurement of the sample.

[0011]

According to the method of manufacturing a plastic member according to the present invention, a single solution having a high volatility and containing no aromatic or olefinic substance is used as a dispersion for forming a plastic substrate into a paste. As a result, the produced plastic member does not originally contain an aromatic substance and an olefinic substance. Therefore, when a liquid comes into contact with the plastic member, the aromatic substance and the olefinic substance are liberated to be in the liquid. There is no risk of elution. As a result, there is no possibility that the measurement result by the liquid chromatograph device or the like or the quality maintenance management in various production processes will be adversely affected (a measurement error or the like).

[Brief description of the drawings]

FIG. 1 shows a chromatogram detected by gradient elution liquid chromatography.

Claims (4)

[Claims] 1. A method for producing a plastic member by adding a dispersion to a particulate plastic substrate to form a paste, extruding the pasted plastic substrate and firing at a high temperature to produce a plastic member. A method for producing a plastic member, characterized by using a single solution which is highly soluble and does not contain an aromatic substance and an olefin substance. 2. The method for producing a plastic member according to claim 1, wherein the dispersion is a linear paraffinic substance containing no unsaturated hydrocarbon. 3. The method according to claim 1, wherein the plastic substrate is polytetrafluoroethylene. 4. The method according to claim 1, wherein the plastic member is a tube, a film, or a film.