JPH09100961A - Heat fusion jointing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat fusion jointing method requiring short time for fusion, advantageous from the viewpoint of heat energy, excellent in the jointed state of a fusion part, with fraction defective remarkably reduced or nil in jointing a tube formed of thermoplastic fluorinated resin and a molding formed of a thermoplastic fluorinated resin by heat fusion. SOLUTION: A tip area 1a of a tube 1 is heated from the peripheral surface side to gelatinize the whole tip area 1a, and tip machining jig is pressed thereto from the axial direction of the tube 1 to deform it into arrowhead shape. The geletinized state at least on the peripheral surface side is maintained or once cooled, and then the peripheral surface side of the arrowhead-shaped part 1b is machined again and gelatinized. On the other hand, the inlet inner surface side of a through hole 2a of a fluorinated resin molding with a through hole inlet formed in funnel shape is heated and gelatinized. The gelatinized parts of the tube 1 and mold 2 are mutually brought into pressure contact and jointed by heat fusion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for heat-sealing a tube (1) made of a thermoplastic fluororesin and a molded article (2) made of a thermoplastic fluororesin.

[0002]

2. Description of the Related Art A tube made of a thermoplastic fluororesin such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) and tetrafluoroethylene-hexafluoropropylene copolymer (FEP) has a corrosion resistance to chemicals. Because of its excellent heat resistance, it is widely used in electronic parts manufacturing factories, chemical factories, etc. as a pipe material for sending ultrahigh-purity water, corrosive chemical liquids, corrosive gases, and the like.

When installing a pipeline made of a fluororesin tube in a factory, connecting the tubes together,
It is often necessary to connect the tube to a fluororesin molding such as a joint. Therefore, various joint systems for fluororesin tubes have been proposed or adopted.

As shown in FIG. 4, one of the typical examples is that one end side of a tube (11) is cold fitted into a through hole (12a) of a molded article (12) such as a joint, Fit the heater member (14) from the outside of the molded product (12), insert the pin-shaped heater member (13) from one end of the tube (11), and then insert it into both heater members (13) and (14). Energize the molded product (12) from the outside
This is a method of heat-gelling until reaching the (12a) side, and heat-gelling the tube (11) from the inside to the outside surface to fuse and integrate both. In FIG. 4, heat transfer states are indicated by arrows. This method is an industrial method that is widely practiced in Japan and abroad.

Japanese Patent Application Laid-Open No. 4-783 filed by the applicant
In Japanese Patent Laid-Open No. 96-96, the tube end side of a fluororesin tube is formed in a thick portion by thermal processing so as to become thick outside, and the tube ends formed in the thick portion are heat-melted. The bonded joint tube and its manufacturing method are shown. The heat-sealing of the tube ends is performed by heating and softening the tube ends of the two tubes by facing each other through the hot plate, and then removing the hot plate to crimp the tube ends of the two tubes.

[0006]

However, in the conventional method shown in FIG. 4, since the heater member (14) must be subjected to mold installation-heating-cooling-demolding every time, one cycle is required. It takes a long time for the tube
In order to supply (11) `` coldly '', it takes time to raise it to a predetermined temperature, and in addition, the molded product (12) is heated from the outside of its wall thickness into the through hole (12a). Heat until it reaches
On the other hand, since the tube (11) uses a method of heating from its inner surface until it reaches the outer surface, it takes time for the fused surfaces to gel properly, and the uniformity of the gelled part However, there are various problems such as requiring a high level of technology for securing the above, and thus tending to cause defective products in the fusion-bonded product at a non-negligible rate.

The method disclosed in Japanese Patent Application Laid-Open No. 4-78396 has a limitation that it is limited to joining tubes together.

In view of such a situation, the present invention provides a method for fusion bonding a tube (1) made of a thermoplastic fluororesin and a molded article (2) made of a thermoplastic fluororesin to each other. It is an object of the present invention to provide a thermal fusion bonding method in which the time required for welding is short, thermal energy is also advantageous, the bonding state of the fusion bonded portion is extremely good, and the defective rate is significantly reduced or eliminated. Is.

[0009]

[Means for Solving the Problems] The heat fusion bonding method of the present invention is a method of heat-sealing a tube (1) made of a thermoplastic fluororesin and a molded article (2) made of a thermoplastic fluororesin. A method of joining, in which the tip region (1a) of the tube (1) is heated from the outer peripheral surface side to gel the entire tip region (1a), and the gelled tip region (1a) is attached to the tube axis. After pressing the tip processing jig (3) from the direction to deform the tip region (1a) of the tube (1) into an arrowhead shape, at least maintain the gelled state on the outer peripheral surface side or once cool it. Reheat the outer peripheral surface side of the arrowhead-shaped portion (1b) to gel it.On the other hand, separately from this, the molded product (2) in which the through hole inlet is shaped to fit the above-mentioned arrowhead shape The inside surface of the inlet of the through hole (2a) is heated by the heating means (4) to gel, and the outer peripheral surface side of the arrowhead-shaped portion (1b) is gelled. Phased tube
The arrow-shaped portion (1b) of (1) is pressed against the inlet of the through hole (2a) of the molded product (2) where the inner surface side of the inlet of the through hole (2a) has gelled, and the tube (1) and molded product (2) is joined with.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

<Tube (1), molded product (2)> As the fluororesin in the tube (1) made of a thermoplastic fluororesin and the molded product (2) made of a thermoplastic fluororesin,
A thermoplastic fluororesin typified by a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) or a tetrafluoroethylene-hexafluoropropylene copolymer (FEP) is preferably used.

This tube (1) is manufactured by extrusion. The diameter and wall thickness of the tube are set arbitrarily.

Examples of the molded product (2) include various molded products such as a joint (straight type, elbow type, T-shaped type, cross type, etc.), a flange type sleeve, and a tube whose end is expanded into a funnel shape. . This molded product (2) is manufactured by a molding method or processing method such as injection molding, transfer molding, machining, extrusion molding or the like.

<Processing of Tube (1) Side> In the present invention, the tip region (1a) of the tube (1) is heated by an appropriate heating means to gel the entire tip region (1a). The length of the tip region (1a) to be heated depends on the diameter of the tube (1) and the molded product.
It depends on the size of (2). It is desirable that the heating be performed without contact, and in order to achieve uniform gelation, use a tube
It is desirable to rotate (1) while rotating at an appropriate speed.

Next, after the tip processing jig (3) is pressed against the gelled tip region (1a) from the tube axial direction to deform the tip region (1a) of the tube (1) into an arrowhead shape, At least the gelled state on the outer peripheral surface side is maintained or once cooled, the outer peripheral surface of the arrowhead portion (1b) is reheated to gel. Also when cooling, reheating is performed in the next step, so that cooling may be performed by allowing the gelled portion to solidify.

Although the inclination angle θ of the arrowhead shape can be set variously,
It is often about 10 ° with respect to the axial direction.

The tip processing jig (3) has a recess having a taper that narrows in depth, and from the bottom of the recess is almost equal to or slightly smaller than the inner diameter of the tube (1). A cylindrical projection having a small diameter and having a long protruding shape is used.

<Processing of molded product (2) side> On the other hand, separately from this, a molded product (2) having a through hole (2a) in which the through hole inlet is shaped to fit the above arrowhead shape is prepared. And its through hole (2a)
The inner surface of the inlet of is heated by the heating means (4) to be gelled.
As the heating means (4), there is used one having a convex portion having a shape corresponding to the entrance of the through hole (2a) and the convex portion being heated.

<Joining of the tube (1) and the molded product (2)> At the stage where such preliminary operation is completed, the arrowhead-shaped portion of the tube (1) in which the outer peripheral surface side of the arrowhead-shaped portion (1b) is gelled (1b)
Is pressed against the inlet of the through hole (2a) of the molded article (2) whose inner surface side of the inlet of the through hole (2a) is gelled. At this time the tube (1)
The rotation of is stopped. And at the time of this pressure contact, the molded product
Insert the pin (P) (having an outer diameter approximately equal to the inner diameter of the tube (1)) from the rear side of (2) through the through hole (2a) and into the tube (1), and (1) Prevent buildup on the inside. Immediately after the pressure contact, it is usual to cool by spraying water in consideration of productivity.
By the above pressure welding operation, heat fusion bonding between the tube (1) and the molded product (2) is achieved almost instantaneously.

<Operation> According to the present invention, the tip side of the tube (1) is formed in an arrow shape, and the arrow-shaped portion (1
The outer peripheral surface side of b) is brought into a gelled state, while the molded article (2) is brought into a gelled state at the inner surface side of the inlet of the through hole (2a). Since the gelled surfaces are pressure-welded to each other, the pressure-bonded surfaces of both are tightly and integrally fused by heat fusion so that the boundary is hard to distinguish.

The heating of the outer peripheral surface side of the arrow-shaped portion (1b) of the tube (1) and the inner surface side of the inlet of the through hole (2a) of the molded product (2) are both non-contact by a heating means. And directly (not from the opposite side through the wall thickness), both joining surfaces can be brought to a uniform gelled state in a short time and in a minimum time.

[0022]

The present invention will be further described with reference to the following examples.

Example 1 FIG. 1 is an explanatory view showing an example of a working state on the tube (1) side in the heat fusion bonding method of the present invention, and FIG. 2 is a molded product (2) in the heat fusion bonding method of the present invention. It is explanatory drawing which showed an example of the heating state of the () side. FIG. 3 is an explanatory view showing a heat fusion bonding procedure of the present invention.

As the tube (1), a PFA (or FEP) tube having an inner diameter of 6 mm and a wall thickness of 1.5 mm obtained by extrusion molding was prepared. As the molded product (2), a flange sleeve made of PFA (or FEP) obtained by injection molding (or machining) was prepared. This molded product (2) has a two-tiered through hole (2a) with an inner diameter of 6 mm on the tip side and a through hole (2b) with an inner diameter of 15 mm on the back side. The inlet is formed in a funnel shape (angle θ = 10 ° with respect to the axial direction) whose opening end side is wide.

In FIG. 1, a tube (1) is rotatably supported by two tube supporting metal fittings (5) and (6) on one end side and the other end side, and a tip region (20 mm) from one end side thereof ( 1
A) is heated in a non-contact state by the tube heating means (7) having a cylindrical shape. During this time, the tip processing jig (3)
In (a) of FIG. 1, it stands by backward, and in (b) of FIG. 1, it is pressed toward the tube support fitting (5).

The tip processing jig (3) has a recess (3a) with a depth of 8 mm having a taper (angle θ = 10 ° with respect to the axial direction) that narrows the depth, and the tube is inserted from the bottom of the recess (3a). A cylindrical long protrusion with a diameter almost equal to the inner diameter of (1).
(3b) has a protruding shape.

FIG. 2 (a) shows the convex portion (4a) of the heating means (4).
In contrast, the molded product (2) supported by the molded product support bracket (8)
The side before the funnel-shaped inlet (2a ') of the through hole (2a) is shown before being inserted. The heating means is shown in FIG.
The funnel-shaped inlet (2a ') side of the through hole (2a) of the molded product (2) supported by the molded product support metal fitting (8) is inserted into the convex portion (4a) of (4), and its The condition where the inlet (2a ') is heated without contact is shown.

FIG. 3 shows a thermal fusion bonding procedure of the present invention. In the figure, the parts indicated by the dots are gelled parts.
Jigs and metal fittings are not shown.

That is, the tube (1) has a tip region (1
a) The whole is gelled by being heated in a non-contact state from the outer peripheral surface side, and the tip processing jig (3) is pressed from the tube axis direction to the gelled tip area (1a), and the tip area (1a) ) Is transformed into an arrowhead shape and is solidified by being cooled in the state of being transformed into the arrowhead shape, and then the outer peripheral surface side of the arrowhead-shaped portion (1b) is reheated and the outer peripheral surface side is gelled. However, if the timing with the heating of the next molded product (2) matches, the cooling and reheating can be omitted, and the state still in gelation after the deformation can be used as it is.

On the other hand, the molded product (2) is brought into a gel state by heating the inlet inner surface side of the through hole (2a) by the heating means (4).

In this state, the inlet side of the through hole (2a) of the molded product (2) is pressed against the tip side of the tube (1), and both gelated parts are heat-sealed. At the time of press contact, insert a pin (P) having an inner diameter of 6 mm from the rear side of the molded product (2) through the through hole (2a) and into the tube (1).

Then, if necessary, the outer corner on the tip side of the molded product (2) is mechanically ground with a cutting tool to finish. Even if burrs are formed on the base end side of the arrow-shaped portion (1b) of the tube (1) or the base end side is uneven, this finishing removes the burrs and unevenness.

A number of heat-fusion-bonded products were manufactured by the above procedure, and the appearance inspection and the airtightness inspection were conducted, but there were no fusion defects.

[0034]

INDUSTRIAL APPLICABILITY In the present invention, both the joint surfaces of the tube (1) made of the thermoplastic fluororesin and the molded article (2) made of the thermoplastic fluororesin are directly contactless ( Because it is heated (not from the opposite side through the wall thickness),
It can bring about a uniform gelation state in a short time and in a minimum time. Since the gelled surfaces are pressure-welded to each other, the pressure-bonded surfaces of both are tightly and integrally fused by heat fusion so that the boundary is hard to distinguish.

Therefore, according to the thermal fusion bonding method of the present invention,
Since the time required for fusion is short and it is also advantageous in terms of thermal energy, productivity is high, and the joining state of the fusion zone is extremely good, and the defective rate is significantly reduced or eliminated. The joined products are excellent in quality.

[Brief description of the drawings]

FIG. 1 is a tube (1) in the heat fusion bonding method of the present invention.
It is explanatory drawing which showed an example of the processing state of the side.

FIG. 2 is an explanatory view showing an example of a heating state of the molded product (2) side in the heat fusion bonding method of the present invention.

FIG. 3 is an explanatory view showing a thermal fusion bonding procedure of the present invention.

FIG. 4 is an explanatory view showing an example of a typical example of a conventional joint system for a fluororesin tube.

[Explanation of symbols]

(1)… Tube, (1a)… Tip region, (1b)… Arrowhead shaped part,
(2)… Molded product, (2a)… Through hole, (2a ′)… Inlet, (2b)… Through hole, (3)… Tip processing jig, (3a)… Recess, (3b)… Protrusion,
(4) ... Heating means, (4a) ... Convex part, (5), (6) ... Tube support metal fittings, (7) ... Tube heating means, (8) ... Molded product support metal fittings, (P) ... Pin , (11)… tube, (12)… molded product, (1
2a) ... through hole, (13) ... heater member, (14) ... heater member

Claims (1)

[Claims] 1. A tube made of thermoplastic fluororesin
A method of heat fusion-bonding (1) and a molded article (2) made of a thermoplastic fluororesin, in which the tip region (1a) of the tube (1) is heated from the outer peripheral surface side and the tip region is heated. (1a) The entire tip is gelled, and the tip processing jig is applied to the gelled tip region (1a) from the tube axis
After pressing (3) to deform the tip region (1a) of the tube (1) into an arrowhead shape, at least maintain the gelled state on the outer peripheral surface side or cool it once and then the arrowhead shape part.
The outer peripheral surface side of (1b) should be reheated to gel.On the other hand, separately from this, the through hole (2a) of the molded product (2a) in which the through hole inlet is shaped to fit the above arrowhead shape ), The inner surface side of the inlet is heated by the heating means (4) to gel, and the outer peripheral surface side of the arrow-shaped portion (1b) is gelated, and the arrow-shaped portion (1b) of the tube (1) is passed through the hole. The inner surface of the inlet of (2a) is gelled, and it is pressed into contact with the inlet of the through hole (2a) of the molded product (2) to form a tube.
A heat fusion bonding method, characterized in that (1) and a molded product (2) are bonded together.