JP2008014324A - Tubular body and method for joining tubular members - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tubular body having a joined portion having a good joined state which is excellent in strength of the joined portion and substantially does not have an adverse effect due to pores.
SOLUTION: A tubular body having a joint portion in which a tubular member (A) and a tubular member (B) are joined, wherein at least one of (A) and (B) is a layer made of a melt processable resin. And at least one layer constituting the laminated tube is made of a melt-processable fluorine-containing resin, and the tubular body has a thickness of each of the formulas (1) to (3) (1). T _i 1> T _i 2 (2) T _o 1 <T _o 2 (3) T _i 1> T _o 1 (in each formula, T _i 1 is the joint surface between (A) and (B). Represents the thickness of the innermost layer at T _i 2, T _i 2 represents the thickness of the innermost layer in a portion other than the joint portion, T _o 1 represents the total thickness of the layers other than the innermost layer at the joint surface, and T _o 2 represents the total thickness of the layers other than the innermost layer in the portion other than the joint portion.) The tubular body that.
[Selection] Figure 1

Description

The present invention relates to a tubular body and a method for joining tubular members.

Fluororesin, especially tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer [PFA] is used because it shows chemical resistance, heat resistance and high cleanliness in the semiconductor industry, chemical industry, food field, pharmaceutical field, etc. It is often used in equipment and production lines.
As a method for joining thermoplastic resin molded products such as fluororesins in various devices and production lines, after joining and melting the joining end faces, the end faces are butted together and welded at a predetermined pressure, so-called butt welding method It has been known.

As a butt welding method, a method is disclosed in which resin tubular parts are made to face each other, end faces facing each other are heated and melted, and then both resin tubular parts are welded relatively close to each other (for example, patents). References 1-3).

In the butt welding method, as a means to suppress bead generation inside the welded part, shape processing is performed so as to incline from the outer periphery to the inner periphery along the pipe end, and it is lowered from the outer periphery to the inner periphery by radiant heat during welding. A method of generating a temperature gradient at the end of the pipe (for example, see Patent Document 2), a method of expanding the internal support of the welded part at the time of pressing when melting the end (for example, see Patent Document 3), etc. Has been.

On the other hand, in recent years, it has been required to perform such butt welding also on a laminated tube made of two layers of melt-processable fluorine-containing resin. However, the above-described known methods have been proposed as techniques for joining tubular members having a single-layer structure, and no reference is made to a method for welding laminated tubes.
JP-A-8-162264 JP-A-1-110128 Japanese Patent Laid-Open No. 3-92335

An object of the present invention is to join a tubular body having a joined portion having a good joined state that is excellent in strength of the joined portion and substantially free from adverse effects due to pores, and a tubular member that can obtain the tubular body. It is to provide a method.

The present invention is a tubular body having a joint portion in which the tubular member (A) and the tubular member (B) are joined, and at least one of the tubular member (A) and the tubular member (B) is melt-processable. It is a laminated tube having two or more layers made of resin, at least one layer constituting the laminated tube is made of a melt-processable fluorine-containing resin, and the tubular body has a thickness of each of the formulas (1) to (3 )
(1) T _i 1> T _i 2
_{(2) T o 1 <T} o 2
(3) T _i 1> T _o 1
(In each formula, T _i 1 represents the thickness of the innermost layer in the joint surface between the tubular member (A) and the tubular member (B), and T _i 2 represents the innermost layer in a portion other than the joint portion. The thickness represents the thickness, T _o 1 represents the total thickness of the layers other than the innermost layer on the bonding surface, and T _o 2 represents the total thickness of the layers other than the innermost layer in the portion other than the bonding portion. It is a tubular body characterized by having the relationship represented by these.

The present invention is a method for joining tubular members, comprising heating and melting the end faces of two tubular members and then welding them, wherein the tubular member has at least one of two or more layers made of melt-processable resin. A tubular member characterized in that at least one layer constituting the laminated tube is made of a melt-processable fluorine-containing resin, and each of the end surfaces is a chamfered outer peripheral portion. This is a joining method.
The present invention is a semiconductor manufacturing apparatus comprising the tubular body of the present invention.
The present invention is a chemical solution supply system to a semiconductor production line, comprising the tubular body of the present invention.
The present invention is described in detail below.

The tubular body of the present invention has a joint where the tubular member (A) and the tubular member (B) are joined. In the tubular body of the present invention, at least one of the tubular member (A) and the tubular member (B) is a laminated tube having two or more layers made of melt processable resin. In the tubular body of the present invention, both the tubular member (A) and the tubular member (B) may be the laminated tube, or one tubular member may have a single-layer structure. Good. In the laminated tube, at least one layer is made of a melt-processable fluorine-containing resin. The melt processable resin and the melt processable resin will be described later.

The tubular body has a relationship in which the thickness of each layer is represented by the formulas (1) to (3).
(1) T _i 1> T _i 2
_{(2) T o 1 <T} o 2
(3) T _i 1> T _o 1
In the above formulas (1) to (3), T _i 1 represents the thickness of the inner layer at the joint surface, T _i 2 represents the thickness of the inner layer at a portion other than the joint portion, and T _o 1 is other than the innermost layer at the joint surface. Represents the total thickness of the layers, and T _o 2 represents the total thickness of the layers other than the innermost layer in the portion other than the joint portion.

FIG. 1 is a schematic diagram in the case where both the tubular member (A) and the tubular member (B) are laminated tubes, and schematically shows the shape of the joint portion of the tubular body of the present invention. In FIG. 1, the parameters of T _i 1, T _i 2, T _o 1, and T _o 2 are shown. These parameters can be measured by cutting the vicinity of the joint portion of the laminated tube in the longitudinal direction and observing the cross section with an optical microscope or a loupe.

In the present invention, the joining surface means a surface that comes into contact when the tubular members are joined together, and the joining portion (also referred to as a welded portion) refers to an end portion of the tubular member that is heated and melted during joining. The whole corresponding part is meant, and the part other than the joined part means a part that was not heated and melted at the time of joining. Each of the above thicknesses is a value measured in the axial direction.

The joint portion in the tubular body of the present invention is different from the portion other than the joint portion in the ratio of the total thickness of the innermost layer and the layer other than the innermost layer, and the thickness ratio of the innermost layer is large. Since the vacancies in the joint surface formed by joining are mainly generated at the portion where the cross section is in contact with the laminate interface, the portion where the cross section is in contact with the laminate interface is located as close as possible to the outer surface of the laminate tube By doing so, defects in the joints caused by the voids are eliminated.

In addition, when the laminated tube has three or more layers, a plurality of holes on the joint surface may be generated, but the total ratio of the thicknesses of the innermost layer and the layers other than the innermost layer is within the above-described range. If the innermost hole is located close to the outer surface, the other holes inevitably close to the outer surface. Therefore, in the present invention, the above parameters are defined.

FIG. 1 is a schematic diagram showing a case of an ideal bonded state. In FIG. 1, an interface notch appears and the shape of the joint has a target axis, so it is clear that this symmetry axis is the joint surface. However, in actuality, depending on the type of pipe used and the like, it may be asymmetrical, so the criteria for determining the joint surface will be described in more detail below.

First, when the joint surface can be visually recognized clearly from the optical micrograph of the cross section, the joint surface is judged by this (judgment criterion 1). In this case, the joining surface may be a curved line, but the length may be determined along the curved line.

When the joint interface cannot be clearly determined by the optical microscope, the joint surface is judged based on the following criteria, and the above-described parameters for the joint surface based on these criteria are calculated.

First, although the joint surface cannot be recognized in the optical micrograph of the cross section, an interface notch may clearly appear (for example, the joint pattern A shown in FIG. 2 or the joint pattern B shown in FIG. 3). Fall under). Here, the interface notch is a bead head recess appearing on the bonding interface. When interface notches clearly appear on both the inside and outside of the tube, the line connecting them is taken as the joining interface. (Judgment criteria 2)

In the determination criterion 2, the joining surface may be parallel to the thickness direction of the tube as in the joining pattern A, or may be oblique to the thickness direction of the tube as in the joining pattern B. However, even if it is diagonal, the bonding interface is determined based on the above criteria.

When the joint surface cannot be visually recognized, and the interface notch does not appear clearly on one or both of the inner surface and the outer surface (for example, when the interface notch does not appear outside the tube shown in FIG. 4) This corresponds to this). On the surface where the interface notch does not appear, the intermediate point between the bead notches is regarded as the above-mentioned interface notch, and the joint surface is determined in the same manner as in the above-described determination criterion 2. The bead notch is a base point where the bead rises on both sides of the bead of the joint. (Criteria 3)

In the present invention, it is possible to determine the joint surface based on the above-described determination criteria 1 to 3, and thereby measure T _i 1, T _o 1 and T _b . For example, even when the bead has a special joint pattern formed so as to be biased to one side as in the joint pattern D shown in FIG. 5, the widths of the inner and outer beads are defined as L _bi and L _bo. Thus, T _i 1, T _o 1 and T _b can be measured on the center line of the bead width. That is, the determination can be made based on the determination criterion 3.

Further, when a step is generated in the joint as in the joint pattern A, it is _important to determine which T _i 1, T _o 1, and T _b is determined by which side, but in principle, T _i 1 is Measurement is performed on the larger value side, and when T _i 1 is the same, a larger value is adopted as the value of T _o 1.

Further, T _b described below has a different value depending on which one is used as a reference line when a step is generated, but the surface where T _b becomes larger is measured as a reference plane.

In addition, although the junction part pattern D (FIG. 5) is formed by the bead being biased to one side, since such a junction part pattern joined the pipes of different types, the tubular member (A) and the tubular part are formed. This occurs when there is a difference in viscosity between the resins constituting the member (B). That is, when a laminated tube and a single-layer tube such as a joint formed by injection molding or the like are welded, the raw material used for the joint or the like generally has a higher MFR than the raw material for tube molding, that is, the viscosity is lower, so the viscosity is higher. This is a joint pattern formed by the beads being biased in the direction of a joint made of a low raw material.

As shown in FIG. 1, a tubular body having a joint obtained by butt joining generally has a bead on the outer side of the joint. Depending on the joining state, there may be a notch. The joint is preferably inside the tube is having no bead or notch, even when having a bead inside the tube, the height T _b of the tube side is represented by the following formula (4) It is preferable that they have the following relationship. The height T _b of the tube side, if within this range, even when used as a fluid transfer member, hardly occurs trouble such as pressure loss and microbubble generator in the transport of fluid.
(4) −0.3 × T _t 2 ≦ T _b <0.7 × T _t 2
In the above formula (4), T _t 2 represents the thickness of the portion other than the joint portion of the tubular member (that is, T _t 2 = T _i 2 + T _o 2), and a positive sign indicates that a bead is formed inside the tube. The negative sign indicates that a notch is formed inside the tube.
The _{T b} is more preferably less than 0.5 × _{T t} 2, more preferably less than 0.1 × _{T t} 2, if it is within the above range, -0.2 × _{T t} 2 or more, more preferably May be −0.1 × T _t 2 or more.
In the present specification, the height T _b of the tube side means the height of the tube side of the joint surface as measured in the axial direction in the tube surface in the portion other than the joint portion from the extended surface in the longitudinal direction .

The tubular body of the present invention preferably has a relationship in which the thickness of each layer is represented by the following formula (5).
(5) 0 ≦ T _o 1 <0.2 × T _i 1
( _Wherein T _o 1 and T _i 1 are the same as defined above.)
If the thickness of each of the above layers is within this range, even if there is no void in the joint or exists in the vicinity of the outer surface, the influence of the void is small. Therefore, problems such as fluid leakage and deterioration of the joint during long-term use do not occur.

Since the shape of the joint portion is limited from the above viewpoint, the tubular body of the present invention may have T _o 1 = 0, that is, the thickness of the outer layer at the joint portion may be zero. . In this case, the portion where the laminated interface and the cross section are in contact with each other is exposed to the outside of the tube, which is preferable in that there is no hole in the bead portion.

If the joint surfaces are T _{o 1} = 0, junction _{T o 3 = 0 (T o} 3 represents. The outer layer thickness at the junction) area of a portion which is the area of the tube outer surface of the joint Preferably it is less than 30%. Since the portion where T _o 3 = 0 is a single-layer state in which no outer layer exists, it is desirable that the number of such portions is as small as possible, and is less than 20% of the area of the outer surface of the tube, more preferably the outer portion of the tube. More preferably, it is less than 10% of the surface area, ideally satisfying T _o 1 = 0 only at the joint surface, and not satisfying T _o 3 = 0 at all other points. It is preferable that

As described above, the tubular body of the present invention has two or more layers made of a melt processable resin as the tubular member (A) and / or the tubular member (B), and at least one layer contains the melt processability. It has a laminated tube made of a fluororesin. Therefore, the tubular body is excellent in strength, chemical resistance, heat resistance and the like.
Furthermore, the tubular body can be made to have low chemical solution permeability by appropriately selecting a melt-processable fluororesin constituting the laminated tube.

In the laminated tube, the layer structure is not particularly limited as long as it has the above-described layers. For example, a two-layer structure of a layer made of a fluorine-free melt-processable resin and a layer made of a melt-processable fluorine-containing resin It may be a three-layer structure having two layers made of a fluorine-free melt-processable resin and one layer made of a melt-processable fluorine-containing resin, or a fluorine-free melt processable resin. A three-layer structure having one layer made of resin and two layers made of melt-processable fluorine-containing resin may be used. Of course, a laminated tube made only of a melt-processable fluorine-containing resin may be used.
In particular, the laminated tube is preferably one in which the innermost layer is a melt-processable fluorine-containing resin.

In the above laminated tube, the thickness of each layer is not particularly limited as long as the bonding surface has a relationship represented by the above formulas (1) to (3), and to the extent that sufficient visible light transmittance is exhibited. can be appropriately adjusted, in the portion other than the joint portion, it is preferable layer thickness ratio thickness of the tube (T t ₂₎ is 5-50%.
In the joint part, the ratio of the length in the longitudinal direction to the wall thickness (T _t 2) of the tube is preferably 0.6 to 3.0, more preferably 1.0 to 1.9.

In the present invention, the melt processable resin is a polymer having melt processability, and includes both a melt processable fluororesin and a fluorine-free melt processable resin.
The fluorine-free melt-processable resin is not particularly limited. Polyamide resins such as nylon resins and aramid resins; polyolefin resins; resins made of ethylene / vinyl alcohol copolymers; polyurethane resins; polyester resins; polyimide resins Polyamide oxide resin; Polyacetal resin; Polycarbonate resin; Acrylic resin; Styrenic resin; Acrylonitrile / butadiene / styrene resin [ABS]; Vinyl chloride resin; Polyether ether ketone resin [PEEK]; Examples thereof include polyethersulfone resin [PES]; polyetherimide resin; polyphenylene sulfide resin.
In this specification, melt processability means the property of a polymer that can measure the melt flow at a temperature higher than the crystallization melting point in accordance with ASTM D-1238 and D-2116.

In the present invention, the above-mentioned melt processable fluororesin is a polymer having melt processability and having at least one hydrogen atom bonded to a carbon atom substituted with a fluorine atom.

The melt processable fluorine-containing resin is not particularly limited. For example, tetrafluoroethylene [TFE] copolymer, chlorotrifluoroethylene [CTFE] copolymer, vinyl fluoride polymer, vinylidene fluoride polymer, and the like. Among them, a TFE copolymer is preferable in terms of corrosion resistance and workability, and a CTFE copolymer is preferable in terms of gas barrier properties, low chemical liquid permeability, and the like.

The TFE copolymer is obtained by copolymerizing tetrafluoroethylene [TFE] with a fluoroolefin other than TFE and / or a fluorine-free ethylenic monomer.

The fluoroolefin other than TFE is not particularly limited. For example, hexafluoropropylene [HFP], perfluoro (alkyl vinyl ether) [PAVE],

Perfluoroethylenic monomers such as vinylidene fluoride [VdF], chloroethylene such as hydrogen-containing fluoroethylenic monomers such as trifluoroethylene, vinyl fluoride, trifluoropropylene, pentafluoropropylene, tetrafluoropropylene, hexafluoroisobutene Examples thereof include fluoroethylenic monomers.
As the PAVE, perfluoro (propyl vinyl ether), perfluoro (ethyl vinyl ether), perfluoro (methyl vinyl ether), and the like can be suitably used from the viewpoint of crack resistance and cost of the obtained resin.
Fluoroolefins other than the above TFE can be used alone or in combination of two or more.

The fluorine-free ethylenic monomer is not particularly limited, and examples thereof include α-olefin monomers having 2 to 10 carbon atoms such as ethylene [Et], propylene, butene and pentene; methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, cyclohexyl Examples thereof include alkyl vinyl ethers having an alkyl group of 1 to 20 carbon atoms such as vinyl ether, hydroxybutyl vinyl ether, and butyl vinyl ether.
The said fluorine-free ethylenic monomer can be used 1 type or in combination of 2 or more types.

As the TFE copolymer, TFE / PAVE copolymer [PFA], TFE / HFP copolymer [FEP], Et / TFE are particularly excellent in corrosion resistance and chemical resistance and have high visible light transmittance. A copolymer or a TFE / VdF copolymer is preferable, and PFA is more preferable in terms of excellent heat resistance.
Even when the above-mentioned TFE copolymer is used as a fluid transfer pipe, it can be preferably used as an inner layer of a laminated pipe in that it does not contaminate the internal fluid and hardly propagates germs.

The CTFE copolymer may be a binary copolymer or a copolymer of three or more. For example, as the binary copolymer, a CTFE / TFE copolymer, CTFE / Examples include PAVE copolymer, CTFE / VdF copolymer, CTFE / HFP copolymer, CTFE / Et copolymer, etc. Examples of the ternary or higher copolymer include CTFE / TFE / HFP copolymer, CTFE. / TFE / VdF copolymer, CTFE / TFE / PAVE copolymer, CTFE / TFE / HFP / PAVE copolymer, CTFE / TFE / VdF / PAVE copolymer, etc. In this case, at least a chlorotrifluoroethylene unit [CTFE unit], a tetrafluoroethylene unit [TFE unit], and a monomer copolymerizable with CTFE and TFE [ It is preferable that a component of the monomer [α] unit derived from a].

In the present specification, the “CTFE unit” and the “TFE unit” are, respectively, a portion derived from CTFE [—CFCl—CF ₂ —] and a portion derived from TFE [—CFFE on the molecular structure of the CTFE copolymer. ₂ -CF 2 _- a], the "monomer [α] unit" Likewise, the molecular structure of the CTFE copolymer, a moiety that monomer [α] is added.

The monomer [α] is not particularly limited as long as it is a monomer copolymerizable with CTFE and TFE, and examples thereof include the monomers described in International Publication No. 2005-100420 pamphlet. Among them, Et, VdF, PAVE, and general formula (I) CX ³ X ⁴ = CX ¹ (CF ₂ ) _n X ² (wherein X ¹ , X ^3, and X ⁴ are the same or different and represent hydrogen X ² represents a hydrogen atom, a fluorine atom, or a chlorine atom, and n represents an integer of 1 to 10, and PAVE is more preferable.

In the CTFE copolymer, the monomer [α] unit is preferably 0.1 to 10 mol%, and the CTFE unit and the TFE unit are 90 to 99.9 mol% in total. The CTFE copolymer has TFE as an essential monomer, and by making the monomer [α] unit within this range, heat resistance, moldability, stress crack resistance, gas barrier property, chemical resistance, The low liquid permeability can be improved.
When the monomer [α] is PAVE, the more preferable lower limit of the monomer [α] unit is 0.5 mol%, the more preferable upper limit is 5 mol%, and the still more preferable upper limit is 3 mol%.
The proportion of each monomer unit in the CTFE copolymer is determined by ¹⁹ F-NMR analysis, infrared spectrophotometer [IR], elemental analysis, and fluorescent X-ray analysis depending on the type of functional group-containing ethylenic monomer unit. It is a value obtained by performing an appropriate combination.

The melt-processable fluorine-containing resin preferably has no unstable terminal such as —COF, —CH ₂ OH, and —CONH _{2 in} view of chemical resistance.
The melt-processable fluorine-containing resin may be a polymer obtained by polymerizing a functional group-containing ethylenic monomer described in International Publication No. 2005-100420 as a comonomer for the purpose of improving interlayer adhesion. .

The melt-processable fluorine-containing resin generally has a melting point of 200 to 380 ° C.
The laminated tube according to the present invention has a melting point difference of 15 ° C. or more between the melt processable resin in the innermost layer and the melt processable resin in the layer provided on the innermost layer in this melting point range. Alternatively, the melting point difference may be 40 ° C. or more and less than 80 ° C.
Conventionally, a laminated tube with a large melting point difference between layers such as the main melting point range has a problem that if the end portion is heated at the time of joining, the melting state becomes non-uniform and the thickness of the joining portion cannot be kept uniform, and the obtained tubular Although there was a problem that defects such as voids occurred in the joint portion of the body, the tubular body of the present invention had these problems even though it had a joint portion joined with a laminated tube having a large melting point difference. Absent.
In the present specification, the melting point is the peak temperature of the heat of fusion curve obtained when the temperature is raised at a rate of temperature rise of 10 ° C./min using a differential scanning calorimeter (device name RDC220, manufactured by Seiko Denshi). It is what I asked for.

In the present invention, the laminated tube only needs to have two or more layers made of the above-described melt processable resin, and among them, one having two layers made of the melt processable fluorine-containing resin is preferable.
The laminated tube is preferably one in which the inner layer is PFA and the outer layer is the CTFE copolymer, the inner layer is PFA and the outer layer is ETFE, etc. in terms of low chemical solution permeability, visibility, etc. In view of low chemical solution permeability, visibility, adhesiveness, and the like, it is more preferable that the inner layer is PFA and the outer layer is the above CTFE copolymer.

In the tubular body of the present invention, when one of the tubular member (A) and the tubular member (B) is a single-layered tubular member, the single-layered tubular member is made of a melt-processable fluorine-containing resin. Is preferable, and a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer [PFA] is more preferable. Examples of the single-layer pipe include a joint formed by injection molding or the like.
In particular, when the laminated tube has an inner layer made of PFA and an outer layer made of a CTFE copolymer, the single-layered tubular body is preferably made of PFA.

The layer or single-layer tube made of the melt-processable fluorine-containing resin in the laminated tube may contain an additive such as a colorant as long as it does not elute into the chemical solution used.

As described above, the tubular body of the present invention is excellent in the strength of the joint.
In the tubular body, for example, the burst pressure between the tubular member (A) and the tubular member (B) at the joint is generally 2.0 MPa or more, preferably 2.5 MPa or more. Since the burst pressure is within the above range, the tubular body is excellent in joint strength.
The bursting pressure is continuously increased at a pressure increase rate of 0.1 MPa / min using water at 25 ° C. for a sample of 30 cm length using T-300N TEST PUMP (manufactured by Kyowa). The maximum stress when the tube bursts is measured.

The tubular body of the present invention can reduce the chemical solution permeability at the joint. For example, the 35% hydrochloric acid permeability coefficient [(g · cm) / (cm ² · sec)] at the joint is 2.0 or less. It can also be made 1.0 or less.
The 35% hydrochloric acid permeability coefficient at the joint is measured by the method described in International Publication No. 2005-100420 pamphlet.

The tubular body of the present invention can be obtained, for example, by chamfering the outer peripheral portions of the end faces of the tubular member (A) and the tubular member (B) and then butt welding them. That is, the tubular body of the present invention can be obtained by joining after controlling the end shape of each tubular member before joining.

The method for joining tubular members of the present invention comprises welding after melting and melting the end surfaces of two tubular members, and the end surfaces of the laminated tubes are formed in advance in the outer peripheral portion before performing the heating and melting. Chamfered.
In the joining method of the present invention, by performing chamfering of the outer periphery before heating and melting, there is a bead of an appropriate size on the outside of the tube, the bead on the inside of the tube is small or absent, and the strength of the joint is high Can be obtained.

The chamfering of the outer peripheral portion can be performed by machining the outer surface of the end portion so that the end portion is tapered.
In the chamfering of the outer peripheral portion, the ratio of the cutting length x at the end of the tubular member to the thickness (T _t 2) of the tubular member is preferably 0.2 to 1.0, more preferably 0.5 to 0. .8.
In the present specification, the cutting length x is a value obtained by measuring the distance in the longitudinal direction from the tube outer side of the end portion after chamfering to the end portion before chamfering.
The chamfering of the outer peripheral portion may be cut so that the inner side of the tube at the end is pointed as shown in FIG. 6, or is cut so that the inner layer portion of the end is pointed as shown in FIG. Also good.
The chamfering of the outer peripheral portion is such that when the inner layer portion is cut so as to have a pointed shape, the height α ₁ of the tapered tip portion measured in the axial direction from the inside of the tube is preferably 10 to 100% of the inner layer thickness T _i 2. More preferably, it can be carried out to be 20 to 80% of the inner layer thickness T _i 2.
The chamfering of the outer peripheral portion is preferably performed such that the cutting angle θ _a (°) satisfies 0 <θ _a <70, and more preferably 15 <θ _a <65.
The said cutting angle (theta) _a means the angle of _a laminated pipe axial direction and an outer peripheral part cutting surface, as shown in FIG.6 and FIG.7.

In the joining method of the present invention, it is preferable that the end surface of the laminated tube is further chamfered on the inner peripheral portion. In the above joining method, when chamfering is performed at both the outer peripheral portion and the inner peripheral portion, there is no bead on the inner side of the tube, or the height T _b on the inner side of the tube is _equal to the above formula (4) −0.3 × T _t. 2 ≦ T _b <0.7 × T _t 2 (T _t 2 is the same as the above definition) is preferable in that the relationship can be satisfied.
The chamfering of the inner peripheral portion can be performed by cutting the tube inner side of the end portion so that the end surface is tapered.
In the chamfering of the inner peripheral portion, the ratio between the cutting length y at the end of the tubular member and the thickness T _{t2 of the} tubular member is preferably 0.05 to 1.0, more preferably 0.1 to 0. 0. 8 is performed.
In the present specification, the cutting length y is a value obtained by measuring the distance in the longitudinal direction from the tube inner side of the end portion after chamfering to the end portion before chamfering.
Chamfering the inner peripheral portion, the height alpha ₂ of the tip portion of the tapered measured from the tube side in the axial direction, preferably 10-100% of the inner layer thickness T _{i 2,} more preferably the inner layer thickness T _{i 2} 20 It can be performed to be ˜80% (see FIG. 8).
The chamfering of the inner peripheral portion is preferably performed such that the cutting angle θ _b (°) satisfies 0 <θ _b <45, and more preferably 5 <θ _b <30.
The said cutting angle (theta) _b means the angle of a laminated pipe axial direction and an internal peripheral part cutting surface, as shown in FIG.

In the joining method of the present invention, when both the outer peripheral portion and the inner peripheral portion are chamfered, the cutting angle θ _a (°) is 20 <θ _a <70 and the cutting angle θ _b (°) is 0 <θ. _b <30 is preferable, the cutting angle θ _a (°) is preferably 30 <θ _a <65, and the cutting angle θ _b (°) is more preferably 5 <θ _b <25.

In the joining method of the present invention, heating and melting can be performed by appropriately selecting conditions according to the type of tubular member to be used, and can be generally performed by heating the end to a temperature of 320 to 400 ° C.
The heating and melting is preferably performed with a heating time of 30 to 100 seconds.

In the joining method of the present invention, the welding after heating and melting can be appropriately set according to the type of tubular member to be used, and is not particularly limited, but the pressing distance is generally 1.2 to 3.5 mm. The pressing speed is generally 400 to 3000 Hz.
In this specification, the pressing distance is a distance described as follows.
First, in the stage before heating and melting of the tubular member, it is fixed to the clamp of the welding apparatus so that the tube end faces are in close contact with each other. This position is the origin. Next, a heating plate is set at the center of the space between the end faces formed by moving one of the clamps so as to retract in the horizontal direction, and heating and melting of the end faces of the tubular member is started. After a predetermined heating time has elapsed, the aforementioned heating plate is retracted below the tubular member. Immediately after that, the clamp is moved horizontally in the direction of the origin, and the melting end faces are pressed against each other. At this time, the welding part is surely formed by excessively pressing past the above-mentioned origin position, and the distance that passes this origin excessively is defined as the pressing distance.
The said pressing speed means the speed | rate at the time of abutting the end surface of each tubular member.

In order to obtain a joint with a specific shape as described above, the pressing distance is extremely important, and the shape of the joint is controlled by setting the pressing distance in the joint in consideration of the shape of the end face. can do.

Since the joining method of the present invention involves chamfering the outer peripheral portion of the end portion of the tubular member in advance before heating and melting and welding the tubular member as described above, the obtained tubular body is the tubular structure of the present invention described above. Similar to the body, the joint bead has an appropriate size and the strength of the joint is high. Moreover, since the tubular body obtained by this joining method has a large inner layer thickness and a very thin outer layer thickness at the joint portion on the laminated tube side, as in the tubular body of the present invention described above, generally no voids are formed. Furthermore, even if the said joining method joins laminated pipes as a tubular member, in the obtained tubular body, the interface X of the interface of the outer layer and inner layer of each laminated pipe and a joining surface is made into one point. So that there are no holes.

In the joining method of the present invention, at least one of the two tubular members is a laminated tube having two or more layers made of a melt processable resin, and at least one layer constituting the laminated tube is a melt processable fluorine-containing layer. It consists of resin.
The laminated tube, the melt processable resin, and the melt processable fluorine-containing resin have the same structure, composition, and physical properties as those described in the tubular body of the present invention.
The laminated tube in the above joining method may have a melt processable resin layer having a melting point range in the above range, and a difference in melting point between the melt processable resin in the inner layer and the melt processable resin in the outer layer is 15 ° C. or more. The difference between the melting points may be 40 ° C. or more and less than 80 ° C.

In the laminated tube in the above bonding method, the inner layer is preferably PFA and the outer layer is preferably the above-mentioned CTFE copolymer in terms of low chemical solution permeability and visibility.
A laminated tube made by laminating these resins generally has a melting point of PFA of about 300 ° C. and a melting point of CTFE copolymer of about 250 ° C., and the melting point difference between the layers is large. There are problems such that the thickness becomes uniform and the thickness of the welded portion becomes non-uniform even after welding, and voids are formed at the welding interface. In order to solve this problem, a method of welding after peeling off the outer layer is also conceivable. However, it is difficult to peel off the outer layer of a laminated tube having high interlayer adhesion, and the barrier property by the outer layer at the peeled site. There is a problem that the functions such as the above are lost or the mechanical strength is lowered. As described above, a problem that has not occurred in welding of tubular members having a single-layer structure occurs in the welding of laminated tubes, but an appropriate welding method has not yet been found.
On the other hand, the tubular body joining method of the present invention can be easily welded even if it is a laminated pipe having a large melting point difference between the layers, and a tubular body having excellent joint strength can be obtained.
That is, in the joining method of the present invention, the end faces of the respective tubes are cut so that the innermost layer occupies most of the obtained joint interface in welding the laminated tubes or between the laminated tubes and the tube having a single layer structure. A tubular member having a strong and stable bonding strength can be obtained by controlling by doing so. Furthermore, this effect can be obtained by unifying the material types constituting the innermost layer and performing the above-described cutting even in a combination having poor adhesion and compatibility between the resins constituting each layer of the tube.

In the joining method of the present invention, if one tubular member is the above-described laminated tube, the other tubular member may be a laminated tube or may have a single layer structure.
The laminated tube as the other tubular member is not particularly limited as long as it has two or more layers made of melt processable resin and at least one layer is made of melt processable fluorine-containing resin. It may be. In the joining method, the two tubular members may be the same kind of laminated tubes.

Although it does not specifically limit as a tubular member which has the said single layer structure, What consists of the above-mentioned melt processable fluorine-containing resin is preferable, and what consists of PFA is more preferable.

The tubular body of the present invention and the tubular body obtained from the joining method of the present invention (hereinafter, these tubular bodies are collectively referred to as “tubular bodies in the present invention”) are suitably used as, for example, transfer members for various fluids. can do.
The tubular body in the present invention is a member of a semiconductor manufacturing apparatus, a chemical liquid supply system in a semiconductor manufacturing line, a tube or hose in a manufacturing apparatus or manufacturing line for various industrial products, a fuel tube such as an automobile fuel tube or an automobile fuel hose. Or it can be used as a fuel hose, a solvent tube or a solvent hose, a paint tube or a paint hose, an automobile radiator hose or brake hose, an air conditioner hose, a food or drink tube or a food or drink hose.
The semiconductor manufacturing apparatus including the above-described tubular body of the present invention and the chemical solution supply system to the semiconductor manufacturing line including the above-described tubular body of the present invention are also one aspect of the present invention.

Since the tubular body of the present invention has the above-described configuration, it is excellent in strength, chemical resistance, heat resistance, and the like, and is excellent in strength even in a joint portion. The tubular member joining method of the present invention is excellent as a method for obtaining a tubular body having excellent strength, chemical resistance, and heat resistance even at the joint.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
The amount of the composition in each example and comparative example is based on mass unless otherwise specified.

Synthesis example 1 (creation of laminated tube)
A chlorotrifluoroethylene [CTFE] copolymer prepared by the same method as in Example 1 of International Publication No. 2005-100420 pamphlet is used as the outer layer, and a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer [ PFA] Pellets (trade name: NEOFLON PFA AP231-SH, manufactured by Daikin Industries, Ltd.), except that the outer layer thickness is 0.5 mm, the inner layer thickness is 1.1 mm, and the inner diameter is 15.9 mm, International Publication No. 2005-100420 A laminated tube was prepared in the same manner as the laminated tube A in the pamphlet.

Example 1
After cutting the end surfaces of the two laminated tubes of Synthesis Example 1 so as to have the shape shown in FIG. 9 (pattern A), respectively, using a PFA welding machine (type RPWF-1410, manufactured by GN Corp.), Each end face was butted and welded under the welding conditions shown in Table 1 to prepare a tubular body of Example 1.

Examples 2-3
After cutting the end surfaces of the two laminated tubes of Synthesis Example 1 so as to have the shape shown in FIG. 9 (pattern B or C), a PFA welding machine (type RPWF-1410, manufactured by GN Corp.) was used. Each end face was butted and welded under the welding conditions shown in Table 1 to produce tubular bodies of Examples 2-3.

Comparative Example 1
Without cutting each end face of the two laminated tubes of Synthesis Example 1 (FIG. 9, pattern D), using a PFA welding machine (type RPWF-1410, manufactured by GS Corp.), the welding conditions shown in Table 1 were used. Each end face was butted and welded to prepare a tubular body of Comparative Example 1.

Comparative Example 2
After cutting the end surfaces of the two laminated tubes of Synthesis Example 1 so as to have the shape shown in FIG. 9 (Pattern E), a PFA welding machine (type RPWF-1410, manufactured by GN Corp.) was used, Each end face was butted and welded under the welding condition 1 to produce a tubular body of Comparative Example 2.

Comparative Examples 3-4
A single-layer tube (Comparative Example 3) using PFA pellets (trade name: NEOFLON PFA AP231-SH, manufactured by Daikin Industries, Ltd.) as a raw material, or a laminated tube of Comparative Example 1 (Comparative Example 4) without a welded portion The body was used in the following tests.

Test Examples The following evaluations were performed on the tubular bodies of the examples and the comparative examples.
(1) Observation of the joint The entire circumference of the welded portion was observed using a zoom loupe (5 times magnification), and the number of holes was confirmed. Further, the welded portion sectional observation by a microscope (50 magnifications) _was calculated _{T i 1, T o 1,} T b. Further, the ratio ω of the area of the portion where T _o 3 = 0 (T _o 3 represents the outer layer thickness at the joint portion) to the area of the outer surface of the tube at the joint portion was also calculated. These results are shown in Table 2.
(2) Joining tube burst pressure T-300N TEST PUMP (manufactured by Kyowa) was applied continuously to a 30 cm long sample at 25 MPa water at a pressure increase rate of 0.1 MPa / min. Pressure was applied and the maximum stress when the tube burst was measured.
(3) 35% hydrochloric acid permeability coefficient It was carried out in the same manner as “35% hydrochloric acid permeability coefficient of laminated tubes A and B” described in International Publication No. 2005-100420 pamphlet.
Each evaluation result is shown in Table 1. Moreover, the shape of the junction part of each tubular body was shown to FIGS.

The tubular body of each example had no holes in the joint, whereas the tubular body of each comparative example had 10 or more holes in the joint. Furthermore, in the tubular body of each example, the difference between the 35% hydrochloric acid permeability coefficient A and the 35% hydrochloric acid permeability coefficient B is 0.05 × 10 ⁻¹³ [(g · cm) / (cm ² · sec)] or less. On the other hand, in the tubular body of each comparative example, the difference between the hydrochloric acid permeability coefficient A and the 35% hydrochloric acid permeability coefficient B is about 0.5 × 10 ⁻¹³ [(g · cm) / (cm ² · sec)]. Met. From this, it turned out that the tubular body of each Example shows the chemical | medical solution low permeability equivalent to before use even if it uses it under stress for a long time unlike each tubular body of Comparative Examples 1-2.

Since the tubular body of the present invention has the above-described configuration, it can be used as a device or a production line in the semiconductor industry, the chemical industry field, the food field, the drug field, and the like. The tubular member joining method of the present invention is excellent as a method for obtaining a tubular body having excellent strength, chemical resistance, and heat resistance even at the joint.

It is a schematic diagram showing the tubular body of the present invention. It is the schematic diagram showing the cross section of the laminated tube (joint part pattern A) in this invention. It is the schematic diagram showing the cross section of the laminated tube (joint part pattern B) in this invention. It is the schematic diagram showing the cross section of the laminated tube (joint part pattern C) in this invention. It is the schematic diagram showing the cross section of the laminated tube (joint part pattern D) in this invention. It is the schematic diagram showing the end surface at the time of chamfering an outer peripheral part from the pipe inner side about the laminated pipe in this invention. It is the schematic diagram showing the end surface at the time of chamfering an outer peripheral part from the inner layer part of an end surface about the laminated tube in this invention. It is the schematic diagram showing the end surface at the time of chamfering an outer peripheral part and an inner peripheral part about the laminated pipe in this invention. It is the schematic diagram showing the cutting pattern of the laminated pipe in each Example and each comparative example. 2 is an optical micrograph of a longitudinal section of a joint in the tubular body of Example 1. FIG. 3 is an optical micrograph of a longitudinal section of a joint in a tubular body of Example 2. FIG. It is an optical microscope photograph of the longitudinal direction cross section of the junction part in the tubular body of Example 3. 4 is an optical micrograph of a cross section in the longitudinal direction of a joint in the tubular body of Comparative Example 1. 4 is an optical micrograph of a cross section in the longitudinal direction of a joint in a tubular body of Comparative Example 2.

Claims (19)

A tubular body having a joint portion in which the tubular member (A) and the tubular member (B) are joined,
At least one of the tubular member (A) and the tubular member (B) is a laminated tube having two or more layers made of a melt-processable resin, and at least one layer constituting the laminated tube contains a melt-processable material. Made of fluororesin,
The tubular body has a thickness of each of the formulas (1) to (3).
(1) T _i 1> T _i 2
_{(2) T o 1 <T} o 2
(3) T _i 1> T _o 1
(In each formula, T _i 1 represents the thickness of the innermost layer in the joint surface between the tubular member (A) and the tubular member (B), and T _i 2 represents the innermost layer in a portion other than the joint portion. The thickness represents the thickness, T _o 1 represents the total thickness of the layers other than the innermost layer in the bonding surface, and T _o 2 represents the total thickness of the layers other than the innermost layer in the portion other than the bonding portion. A tubular body characterized by having a relationship represented by: Junction, the tubular body of claim 1 having a relationship height T _b of the tube side is represented by the formula (4).
(4) −0.3 × T _t 2 ≦ T _b <0.7 × T _t 2
(In the formula, T _t 2 represents the thickness of the portion other than the joint portion of the tubular member, the positive sign represents that a bead is formed inside the pipe, and the negative sign represents a notch formed inside the pipe. (It means being done.) The tubular body according to claim 1 or 2, wherein the tubular body has a relationship in which the thickness of each layer is represented by the formula (5).
(5) 0 ≦ T _o 1 <0.2 × T _i 1
(Wherein T _o 1 and T _i 1 are the same as defined above.) The joint portion has an area of a portion where T _o 3 = 0 (T _o 3 represents an outer layer thickness in the joint portion) is less than 30% of an area of a tube outer surface of the joint portion. 3. The tubular body according to 3. The tubular body according to claim 1, 2, 3, or 4, wherein both the tubular member (A) and the tubular member (B) are laminated tubes having two or more layers made of melt processable resin. The tubular body according to claim 1, 2, 3 or 4, wherein one of the tubular member (A) and the tubular member (B) is a laminated tube and the other is a single layer tube made of a melt-processable fluorine-containing resin. The tubular body according to claim 6, wherein the single-layer tube is made of a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer. The laminated tube has a melting point difference of 15 ° C or more between the melt processable resin in the innermost layer and the melt processable resin in the layer provided on the innermost layer. The tubular body according to 5, 6 or 7. The tubular tube according to claim 8, wherein the laminated tube has a difference in melting point between the melt processable resin in the innermost layer and the melt processable resin in the layer provided on the innermost layer of 40 ° C or higher and lower than 80 ° C. body. The laminated tube is composed of two layers in which an inner layer is a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer and an outer layer is a chlorotrifluoroethylene copolymer. The tubular body according to 5, 6, 7, 8 or 9. A method of joining tubular members, comprising welding after melting and melting each end face of two tubular members,
The tubular member is a laminated tube having at least one layer made of melt processable resin, and at least one layer constituting the laminated tube is made of melt processable fluorine-containing resin,
The end face of the laminated tube is obtained by chamfering an outer peripheral portion in advance before performing the heat-melting method. The method for joining tubular members according to claim 11, wherein the end surface of the laminated tube is further chamfered at the inner periphery. The tubular member joining method according to claim 11 or 12, wherein both of the two tubular members are laminated tubes. The method of joining tubular members according to claim 11 or 12, wherein one of the two tubular members is a laminated tube and the other is a single layer tube made of a melt processable resin. The laminated tube has a melting point difference of 15 ° C or more between the melt processable resin in the innermost layer and the melt processable resin in the layer provided on the innermost layer. Method for joining tubular members. The tubular tube according to claim 15, wherein the laminated tube has a difference in melting point between the melt processable resin in the innermost layer and the melt processable resin in the layer provided on the innermost layer of 40 ° C or higher and lower than 80 ° C. Member joining method. The laminated tube is composed of two layers in which an inner layer is a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer and an outer layer is a chlorotrifluoroethylene copolymer, 11, 12, 13, 14, The method for joining tubular members according to 15 or 16. 11. A semiconductor manufacturing apparatus comprising the tubular body according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10. A chemical solution supply system to a semiconductor production line, comprising the tubular body according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.