JPH0346559A - Quartz glass capillary - Google Patents

Abstract

PURPOSE:To allow the repetitive use of the capillary at a high temp. by using a silicon modified polyimide layer to form a heat resistant protective layer in contact with the outside surface of a quartz glass tube. CONSTITUTION:The heat resistant protective layer in contact with the outside surface of the quartz glass tube 1 is formed of the silicon modified polyimide layer 3. The quartz glass tube 1 formed to 0.05 to 1.0mm inside diameter and about 0.05 to 0.2mm thickness is used in this case and is formed by drawing the relatively large-size quartz glass tube, which is synthesized in the absence of water, to a small diameter by a drawing furnace kept at about 2,000 deg.C. Polyimide having a siloxane structure in the main chain or side chain is used as the silicon modified polyimide layer 3. The repetitive use of the capillary at the high temp. is possible as the capillary is formed in such a manner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a quartz glass capillary. In particular, it relates to a quartz glass capillary whose outer surface is coated with a heat-resistant protective layer.

[Conventional technology]

Silica glass capillaries are used as separation columns in gas chromatography, liquid chromatography, supercritical fluid chromatography, ion chromatography, electrophoretic analysis, and the like. For example, when used as a column for gas chromatography, the quartz glass capillary is made of SUS
It exhibits higher resolution than conventional columns using stainless steel or multi-component glass capillaries, and has the advantage of being applicable to trace analysis.

Fused silica capillaries usually have an inner diameter of 0.05 to 1,
Q+nm and a thickness of about 0.05 to 0.2 mm are used. FIG. 3 shows an example of a cross section of a conventional silica glass capillary for gas chromatography. 1 is a quartz glass tube, 2 is a stationary phase, and 5 is a heat-resistant protective layer.

To manufacture such a quartz glass capillary column, first, an anhydrous synthesized quartz glass base material is heated to a temperature of about 2,000 yen.
A quartz glass tube 1 is produced by thinly drawing the tube in a drawing furnace at .degree. C., and immediately after drawing, it is covered with a heat-resistant protective layer 5. Here, the quartz glass tube 1 is cut to an appropriate length, and the inner surface of the quartz glass tube 1 is subjected to surface treatment with a silane coupling agent, etc., and then a stationary phase 2 made of silicone (for example, polydimethylsiloxane), polyethylene glycol, etc. is formed.

The heat-resistant protective layer 5 provided on the surface of the quartz glass tube is exposed to a high temperature of about 350° C. when coating the inner surface of the quartz glass tube or when using the completed column. Therefore, the heat-resistant protective layer 5 must be able to withstand high temperatures of about 350°C.

Conventionally, heat-resistant protective layers have been made of metals such as aluminum, polyimide resins (for example, see Japanese Patent Publication No. 62-36537 and Japanese Patent Publication No. 61-68561), and silicone rubber (see, for example, Japanese Patent Publication No. 62-36537). etc. have been proposed.

To coat a quartz glass tube with aluminum, a method is used in which a heated and stretched quartz glass tube is passed through a die filled with molten aluminum.

To coat with a heat-resistant protective layer of polyimide resin, as in the production of enamelled electric wires, a solution of polyimide resin in an organic solvent is coated with a die to a predetermined thickness, and the solvent is evaporated in a heating furnace to harden the coating. let

The polyimide resin is usually an aromatic polyimide, such as a polycondensate of trimellitic anhydride and 4,4''-diaminodiphenyl ether (such as DuPont's Pyre
ML).

Although the above-mentioned polyimide has sufficient heat resistance, it has the disadvantage of poor flexibility and weak adhesion to glass. Therefore, in order to improve the adhesion to glass, it has been disclosed in Japanese Patent Application that a silane coupling agent is added to the polyimide solution. This was proposed in No. 141554/1983.

The silicone rubber coating allows the column to be used at a temperature of 250°C.
It is used in cases where the degree of
537).

[Problem to be solved by the invention]

However, among the above heat-resistant protective layers, the aluminum coating has a significantly large difference in thermal expansion coefficient from quartz glass (silica glass 5.7 x 100-7de argonium 2
．． 3x10-5deg'), when the capillary is subjected to thermal history, peeling occurs at the interface between the quartz glass and the aluminum film, and the bending strength of the capillary is significantly reduced. Another problem is that in molten argonium at a temperature of 660°C or higher, the outer surface of the quartz glass tube is scratched by contact with the fine aluminum grains mixed therein, and the capillary often breaks when wound into a coil. Ta.

Furthermore, polyurethane resin has weak adhesion to quartz glass and poor flexibility. Therefore, if the column is used repeatedly at high temperatures, the coating will peel off from the quartz glass tube and the column will often break.

The method described in JP-A-57-141554, which involves adding a silane coupling agent to a polyimide solution, was proposed as a means to improve the adhesion with quartz glass. This had the disadvantage that the pot life of the liquid was extremely short due to the reaction with the liquid, making it unsuitable for practical use.

Silicone rubber is a substance used as a stationary phase on the inner surface of a capillary, but when used as a heat-resistant protective layer on the outer surface of a capillary, its mechanical strength is low, so it does not function well as a protective layer, and the capillary is damaged. Easy to break.

Therefore, an object of the present invention is to provide a quartz glass capillary that has a heat-resistant protective layer on the outer surface of the quartz glass tube that has sufficient mechanical strength and strong adhesion to glass, and that does not break even when used repeatedly at high temperatures. It is to provide.

Another object of the present invention is that the difference in thermal expansion coefficient between the heat-resistant protective layer and the quartz glass is small, so that the heat-resistant protective layer does not peel off at the interface with the quartz glass even when subjected to thermal history, and has a protective effect against breakage. The goal is to provide a fused silica capillary that retains its properties.

Yet another object of the present invention is to provide a fused silica capillary that does not break when wound into a coil.

Another object of the present invention is to provide a quartz glass cavity having a heat-resistant protective layer, which can be provided with a coating solution having a sufficiently long pot life.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a quartz glass capillary having a heat-resistant protective layer on the outer surface of the quartz glass tube, in which the outer surface of the quartz glass tube is coated with a protective layer of silicone-modified polygon. The silicone-modified polyimide protective layer is provided in direct contact with the outer surface of the quartz glass tube, and another heat-resistant protective layer may be provided on the outside thereof.

The quartz glass capillary having a heat-resistant protective layer of the present invention consists of the following elements.

(1) Quartz glass tube (2) Protective layer of silicone-modified polyimide formed on the outer surface of the quartz glass tube Each element will be explained in detail below.

(1) Quartz glass tube usually has an inner diameter of 0.05 to 1.0 mm and a TFJ of 0.05 mm.
A material with a diameter of about 0.2 mm to 0.2 mm is used. As usual,
A relatively thick anhydrous synthesized quartz glass tube is heated to a temperature of approximately 20°C.
It can be made by thinly drawing it in a drawing furnace at 00°C.

(2) Protective layer of silicone modified polyimide formed on the outer surface of the quartz glass tube As shown in FIG. 1, a heat-resistant protective layer 3 of silicone modified polyimide is provided on the outer surface of the quartz glass tube 1.

The silicone-modified polyimide used in the present invention is a polyimide having a siloxane structure in its main chain or side chain. Those having a siloxane structure in the main chain are preferred.

The silicone-modified polyimide suitable for the present invention is a polymer having an imide ring formed from boriagottutaic acid and a siloxane structure in the main chain. For example, it is a polymer represented by the following structural formula (I).

(I) During the ceremony, 1 is a tetravalent aromatic group, z is a divalent aroma Represents an aromatic group.

1 For example, (however, X is an oxygen atom.

sulfur atom.

carbonyl Base.

(indicates methylene group, etc.) etc.

2 teeth, for example etc.

R3 and R4 each represent an alkyl group or an aryl group. For example, methyl group, phenyl group.

This silicone-modified polyimide is formed from an oligomer consisting of a polyamic acid whose main chain has the ability to form a diamond ring and a siloxane structure by ring closure and polymerization of the polyamic acid. This oligomer has the following structural formula (n)
It is expressed as

0 Such oligomer solutions, such as N-methylpyrrolidone solutions, are available as paints.

To form a protective layer of silicone-modified polyide on the outer surface of the quartz capillary, a coating composition made of the above oligomer solution is coated on the outer surface of the quartz glass tube using a wire coating die, and the coating is passed through a heating furnace. The solvent is evaporated and the coating is cured. At this time, the oligomer undergoes dehydration and ring closure of the boric acid and the polymerization progresses, resulting in the oligomer having the structural formula (I).
It is a silicone-modified polyimide represented by

This polyamide is, for example, KJR-6 manufactured by Shin-Etsu Chemical Co., Ltd.
51, JR-370 manufactured by Nitto Electric Industry ■, P manufactured by Hitachi Chemical ■
Although it is commercially available as IX etc., the polyimide used in the present invention is of course not limited to these.

The silicone-modified polyimide protective layer may contain other heat-resistant resins, such as polyimide, in an amount that does not impair adhesion to quartz glass.

When polyimide is included, heat resistance can be further improved.

The thickness of the silicone-modified polyimide layer is usually about 3 μm or more when it alone constitutes a heat-resistant protective layer. When further coated with another heat-resistant protective layer as described below, the preferred thickness is about 3 μm to about 15 μm. Within this range, the adhesion to quartz glass is sufficiently improved, and the deformation of the silicone-modified polyimide layer at high temperatures is small.

The quartz glass capillary of the present invention may include the following elements as necessary.

(3) Stationary phase formed on the inner surface of the quartz glass tube When the quartz glass capillary of the present invention is used as a capillary column in applications such as gas chromatography, a stationary phase is formed on the inner surface of the quartz glass tube. This can be done either by passing a solution of a stationary phase forming substance into a quartz glass tube and then passing a suitable inert gas through it to evaporate the solvent (dynamic method), or by filling a quartz capillary with a solution of a stationary phase forming substance and then starting from one end. The solvent is sequentially heated and evaporated (static method). Figure 1 shows stationary phase 2.
It is shown as.

Stationary phase forming substances include, for example, polydimethylsiloxane,
Siloxanes such as phenylmethylborisiloxane, polyethylene glycols, etc. can be used.

As the solvent, for example, methylene chloride, n-pentane, diethyl ether, etc. can be used.

In order to heat the solvent in the quartz capillary in the static method, there are two methods: heating the outside of the quartz capillary by contacting a liquid with a temperature higher than the evaporation temperature of the solvent by a predetermined temperature, for example, 20°C or more, There is a method of dielectric heating using irradiation.

It is more preferable that the silica glass capillary of the present invention further includes the following elements.

3 (4) A heat-resistant protective layer further formed on the silicone-modified polyimide layer on the outer surface of the quartz glass tube.

As shown in FIG. 2, a heat-resistant protective layer 4 other than silicone-modified polyimide may be provided further above the silicone-modified polyimide protective layer 3 on the outside of the quartz glass tube 1. The heat-resistant protective layer 4 may be a polyimide layer or may be made of metal such as aluminum.

Polyimides suitable for the above purpose are aromatic polyimides such as those mentioned above, such as polycondensates of trimellitic anhydride and 4,4'-diaminodiphenyl ether (for example, Pyre ML manufactured by DuPont).

The polyimide of the heat-resistant protective layer provided further above the silicone-modified polyimide protective layer may be a polyimide different from the polyimide component in the silicone-modified polyimide.

When used as a capillary column using polyethylene glycol or the like as a stationary phase used at relatively low temperatures, polyimides other than aromatic polyimides can also be used. Further, as the heat-resistant resin other than polyimide, for example, polyamide, polytitanocarbosilane, organopolysil-sesquioxane, etc. can also be used.

A typical polytitanocarbosilane has the following structural formula: % R represents an alkyl group (for example, a methyl group), and q is a positive integer representing the degree of polymerization.

A typical organopolysil-sesqui-oxane is represented by the following structural formula (IV).

Rs, R2R7, and R8 each represent a methyl group or a phenyl group, and may be the same or different. r is a positive integer representing the degree of polymerization.

Polytitanocarbosilane and organopolysilsesqui-oxane have better heat resistance and corrosion resistance than polyimide polymers.

According to the present invention, when these heat-resistant protective layers are provided on quartz glass via a silicone-modified polyimide layer, better adhesion is obtained than when used alone. Furthermore, superior heat resistance can be obtained compared to when a silicone-modified polyamide layer is used alone as a heat-resistant protective layer.

When providing these heat-resistant protective layers on the silicone-modified polyimide layer, the silicone-modified polyimide may be cured or semi-cured and then a layer of polyimide etc. may be applied and cured, or the silicone-modified polyimide film may be cured. It is also possible to apply a layer of polyimide or the like without this, and then cure the two layers at the same time. The silicone-modified polyimide and unmodified polyimide of the heat-resistant protective layer may be cured by heat as usual, by using an electron beam or other ionizing radiation, or by using ultraviolet rays. When curing with ultraviolet light is used, it is desirable to introduce a suitable photosensitive functional group into the molecule.

Silicone-modified polyimide layer and other heat-resistant resins,
For example, even when polyimide is included, a heat-resistant protective layer made of polyimide or the like may be provided on the silicone-modified polyimide layer.

[Effect]

The outer surface of the quartz glass capillary of the present invention is provided with a heat-resistant protective layer made of silicone-modified polyimide that has excellent adhesion to quartz glass.
It acts as a protective layer to prevent folding during handling during manufacturing such as stationary phase formation, coil winding, and use as a column.

The quartz glass capillary of the present invention is useful as a separation column in gas chromatography, liquid chromatography, supercritical fluid chromatography, ion chromatography, etc. if a stationary phase is provided on the inner surface.

7 Hereinafter, the present invention will be explained in more detail with reference to Examples.

[Example 1] An anhydrous synthetic quartz glass tube was softened in a drawing furnace at a temperature of about 2000°C and drawn into a quartz capillary with an inner diameter of 0.35 mm and an outer diameter of 0.45 M. Immediately after stretching, the outer surface was coated with a heat-resistant resin as described below.

N- containing 30% silicone-modified polyimide precursor (oligomer) consisting of polyamic acid obtained by the reaction of pyromellitic dianhydride and 3,3''-cyanodiphenyl ether and polydiphenylsiloxane. Repeat application of methylpyrrolidone solution 3 times and increase temperature to 500°C.
It was dried and cured in an electric furnace at 0.degree. C. to form a silicone-modified polyimide layer with a thickness of 15 .mu.m.

A quartz capillary coated with a heat-resistant protective film is 50 m long.
The inside of the quartz tube was silylated by a conventional method to form a thin film of polydimethylsiloxane on the inner surface. FIG. 1 shows a cross section of a quartz glass capillary having a stationary phase on its inner surface obtained in Example 1.

When the thus produced silica glass capillary column was wound around a mandrel with an outer diameter of 5 mm and placed in a constant temperature bath kept at 180°C for 30 minutes, no breakage of the capillary was observed.

However, when the temperature was raised to 350''C under the same conditions, the capillary broke.

[Example 2] A quartz glass tube stretched in the same manner as in Example 1 was coated with a heat-resistant resin on its outer surface as described below.

A solution of N-methylpyrrolidone containing 30% of a silicone-modified polyimide precursor (oligomer) consisting of polyamic acid and polydiphenylsiloxane obtained by the reaction of pyromellitic dianhydride and 3,3'-diaminodiphenyl ether was added once. It was applied, dried and semi-cured in an electric furnace at a temperature of 300°C. On this semi-cured film, an N-methylpyrrolidone solution containing 25% of polyamic acid obtained by the reaction of pyromellitic dianhydride and 3,3'-cya-nodiphenyl ether was applied, and the temperature was 500°C.
It was dried and cured in an electric furnace (C) to form a polyimide protective film. The film thickness was 5 μm for the silicone-modified polyimide film and 10 μm for the polyimide film.

A quartz capillary coated with a heat-resistant protective film is 50 m long.
The inside of the quartz tube was silylated by a conventional method to form a thin film of polydimethylsiloxane on the inner surface. FIG. 2 shows a cross section of a quartz glass capillary having a stationary phase on its inner surface obtained in Example 2.

When the thus produced silica glass capillary column was wound around a mandrel with an outer diameter of 5 mm and placed in a constant temperature bath maintained at a temperature of 350°C for 30 minutes, no breakage of the column was observed.

[Example 3] A quartz glass tube stretched in the same manner as in Example 1 was coated with a heat-resistant resin on its outer surface in the following manner.

25% silicone-modified polyimide precursor (oligomer) consisting of polyamic acid and polydimethylsiloxane obtained by the reaction of benzophenone tetracarboxylic dianhydride and tetragonobiphenyl.
A polyamic acid obtained by the reaction of pyromellitic dianhydride and 3,3"cyanodiphenyl ether was applied on top of the N-methylpyrrolidone solution containing 25% of the polyamic acid.
% N-methylpyrrolidone solution was applied and the temperature was 5.
The film was dried and cured in an electric furnace at 00°C to form a heat-resistant protective film. The film thickness was 5 μm for the silicone-modified polyimide film and 20 μm for the 1 polyimide film.

A thin film of polydimethylsiloxane was formed on the inner surface of the quartz tube in the same manner as in Example 2. The resulting quartz glass capillary column showed no breakage even when it was wound around a mandrel with an outer diameter of 5 mm and placed at a temperature of 350°C for 30 minutes.

[Example 4] The outer surface of a quartz glass capillary drawn in the same manner as in Example I was coated with a heat-resistant resin in the following manner.

Benzophenone tetracarboxylic dianhydride and 4.4”-
A solution of N-methylpyrrolidone containing 25% of a silicone-modified polyimide precursor (oligomer) consisting of liagotutaic acid and polydiphenylsiloxane was applied to the boron obtained by the reaction of oxydianiline at a temperature of 500°C.
It was dried and cured in an electric furnace of C. On this coating, an isoigod oligomer (NS) having an ethynyl group at the end is applied.
N containing 40% of Surgorad I P-360 manufactured by Company C
-Methylpyrrolidone solution was applied, dried and cured in an electric furnace at a temperature of 500°C to form a heat-resistant protective film. The film thickness was 10 μm for the silicone-modified polyimide and 15 μm for the polyimide.

A thin film of polydimethylsiloxane was formed on the inner surface of the quartz tube in the same manner as in Example 2. The resulting quartz glass capillary column showed no breakage even when it was wound around a mandrel with an outer diameter of 5 mm and placed at a temperature of 350°C for 30 minutes.

[Example 5] Formed. FIG. 2 shows a cross section of a quartz glass capillary having a stationary phase on its inner surface obtained in Example 2.

2 The quartz glass capillary column thus produced was wrapped around a mandrel with an outer diameter of 5 mm and placed in a constant temperature bath kept at 350°C for 30 minutes. -Methylpyrrolidone solution was applied once and dried and cured in an electric oven at a temperature of 500°C.

On top of this film, polyamideimide was applied and the temperature was 48°C.
It was dried and cured in an electric oven at 0°C.

The film thickness was 5 μm for the silicone-modified polyimide and 10 μm for the polyimide.

A thin film of polydimethylsiloxane was formed on the inner surface of a quartz tube in the same manner as in Example 1. Even when the obtained quartz glass capillary column was wound around a mandrel with an outer diameter of 5 mm and placed at a temperature of 300°C for 30 minutes, no breakage of the column was observed.

[Example 6] Instead of polyamideimide in Example 5, organopolysil-sesqui-oxane having the structural formula (TV) in which R', R6, R7, and R'' are all phenyl groups was applied,
A quartz glass capillary column was obtained in the same manner as in Example 5, except that it was dried and hardened at a temperature of 500°C.

Even when this column was wound around a mandrel with an outer diameter of 5 mm and placed at a temperature of 350° C. for 30 minutes, no breakage of the column was observed.

[Example 7] Quartz was produced in the same manner as in Example 6, except that polytitanocarbosilane having the structural formula (II[) and R being a methyl group was used instead of the organopolysil-sesquioxane in Example 6. A glass capillary column was obtained.

Even when this column was wound around a mandrel with an outer diameter of 5 mm and placed at a temperature of 350° C. for 30 minutes, no breakage of the column was observed.

[Example 8] A quartz glass capillary, which was stretched in the same manner as in Example 1 and whose outer surface was coated with silicone-modified polyimide with a thickness of 5 μm, was passed through a die containing molten aluminium to form a capillary with a thickness of 10 μm. coated with an aluminum layer. No capillary breakage occurred during this process. A stationary phase was formed on the inner surface of the quartz tube in the same manner as in Example 1.

The obtained quartz glass capillary column was sized to have an outer diameter of 5 mm.
Even when the column was wound around a mandrel and left at a temperature of 300''C for 30 minutes, no breakage of the column was observed.

[Example 9] In Examples 1 and 2.3, in place of the silicone-modified polyimide precursor, 50% of the same silicone-modified polyimide precursor as used in Example 1, pyromellitic dianhydride, and 3,3 A mixture of a polyimide precursor (oligomer) consisting of a polyamic acid obtained by the reaction of -diaminodiphenyl ether with 50% was applied to a quartz capillary as a 30% N-methylpyrrolidone solution. Similar results to Examples 1, 2.3 were obtained.

[Comparative Example I]

In Example 1, the coating with silicone-modified polyimide was omitted, and the outer surface of the quartz glass was directly coated with poly-5-imide. The film thickness was 15 μm. A stationary phase was formed on the inner surface of the quartz tube in the same manner as in Example 1.

The obtained quartz glass capillary column had an outer diameter of 20 mm.
When the column was wound around a mandrel and left at a temperature of 350° C. for 30 minutes, the polyimide coating was partially peeled off, and the column broke at that location.

[Comparative Example 2] In Comparative Example 1, the outer surface of the quartz glass was subjected to silane coupling treatment in a conventional manner before coating with polyimide.

The obtained quartz glass capillary column had an outer diameter of 20II
Wrap it around a III+ mandrel and heat it to 350°C.
No breakage occurred when the column was left for 0 minutes, but when it was wound around a mandrel with an outer diameter of 5 mm, the boiling film partially peeled off and the column broke at that location.

[Comparative Example 3] In Example 2, instead of the silicone-modified polyimide, N-methyl containing 15% of an oligomer of trimellitic dianhydride and 4.4”-di6-socyanate diphenylmethane (polyamide precursor) was used. Used as pyrrolidone/naphtha mixture solution, otherwise Example 2
A quartz glass capillary column was obtained in the same manner as described above.

When the obtained column was wound around a mandrel with an outer diameter of 20 mm and placed at a temperature of 350° C. for 30 minutes, peeling of the polyimide film was observed in some parts, and the column was broken at that location.

[Comparative Example 4] In Example 2, a polyester-modified polyimide precursor was added in cresol instead of silicone-modified polyimide.
A quartz glass capillary column was obtained in the same manner as in Example 2 except that the solution was used as a 0% solution.

The heat resistance of the obtained silica glass capillary column was the same as that of Comparative Example 3.

[Comparative Example 5] In Example 8, the silicone-modified polyimide coating was omitted, and the quartz capillary was directly coated with an aluminum laminate to a thickness of 15 μm.

The obtained quartz glass capillary column had an outer diameter of 20 mm.
When it was wound around a mandrel, some breakage was observed.

When the wound product was placed at a temperature of 350° C. for 30 minutes, the aluminum coating peeled off in some places, and the column broke at those places.

〔Effect of the invention〕

The quartz glass capillary according to the present invention has a heat-resistant protective layer on the outer surface of the quartz glass tube that has sufficient mechanical strength and strong adhesion to glass, and will not break even when used repeatedly at high temperatures.

In the present invention, even if a conventional poly-11 layer with poor adhesion to quartz glass is further provided on the silicone-modified polyimide layer as a heat-resistant protective film on the outer surface of the capillary, the silicone-modified polyimide layer is Because of the intervening layer, it has good adhesion to quartz glass and does not break even when the capillary is used repeatedly at high temperatures for gas chromatography and the like. In this case, it is possible to achieve heat resistance 8 which is superior to the case where the silicone-modified polyimide layer is used alone.

Furthermore, unlike the case where a metal such as argonium is used for the heat-resistant protective layer, the quartz glass capillary according to the present invention has the advantage that even though there is a difference in thermal expansion coefficient between the heat-resistant protective layer and the quartz glass, the bond between the two Because the force is strong, the heat-resistant protective layer does not peel off at the interface with the quartz glass even when subjected to thermal history, and the protective effect against breakage is maintained. That is, in the quartz glass capillary of the present invention, even when subjected to thermal history, the heat-resistant protective layer does not partially peel off, so it does not break.

Furthermore, the quartz glass capillary according to the present invention has a silicone-modified polyimide layer, even if the quartz glass tube is passed through molten aluminum and an aluminum coating is applied to the outer surface of the quartz glass capillary. Since it does not scratch the surface, it will not break when rolled into a coil.

Further, according to the present invention, a coating liquid having a sufficiently long pot life can be used when providing a heat-resistant protective layer.

9. The quartz glass capillary of the present invention can be manufactured using the same manufacturing method as conventional methods. If a tandem line is used in the process, it is easy to coat two heat-resistant protective layers.

The quartz glass capillary of the present invention is useful as a separation column in gas chromatography, liquid chromatography, supercritical fluid chromatography, ion chromatography, electrophoretic analysis, and the like. The silica glass capillary of the present invention is also useful as a transfer tube for transporting gaseous or liquid samples from these separation columns to detectors such as mass spectrometers, infrared spectrometers, and ultraviolet spectrometers.

[Brief explanation of drawings]

FIG. 1 is a sectional view of one embodiment of the quartz glass capillary of the present invention. FIG. 2 is a sectional view of another embodiment of the quartz glass capillary of the present invention. FIG. 3 is a cross-sectional view of a conventional gas chromatography column using a silica glass capillary. Explanation of symbols 1----------Quartz capillary 0 2----------Stationary phase 3-----Silicone modified polyimide 4----
−−・・−・−Polyimide layer 5・・−1−−−−・−Heat resistant protective layer d layer

Claims (4)

[Claims] (1) A quartz glass capillary having at least one heat-resistant protective layer on the outer surface of the quartz glass tube, characterized in that the heat-resistant protective layer in contact with the outer surface of the quartz glass tube is a layer of silicone-modified polyimide. fused silica capillary. (2) The silica glass capillary according to claim 1, wherein the at least one heat-resistant protective layer comprises the silicone-modified polyimide layer and another heat-resistant protective layer. (3) The quartz glass capillary according to claim 2, wherein said other heat-resistant protective layer is made of polyimide. (4) The quartz glass capillary according to claim 2, wherein said other heat-resistant protective layer is made of aluminum.