JPH01257031A - Joined article made of fluorine resin and its manufacture - Google Patents

Abstract

PURPOSE:To obtain joined parts whose weld part is free from generation of bubbles without making use of an odd-shaped sleeve by a method wherein a medium and large diameter tubular bodies made of fluororesin are outserted on an end part of a plurality of small diameter tubular bodies made of the fluororesin and joining among the small diameter tubular bodies, that between the small diameter tubular body and medium diameter tubular body and that between the medium diameter tubular body and large diameter tubular body are performed at the end part. CONSTITUTION:Both end parts of a plurality of small diameter tubular bodies 1 made of fluororesin are arranged almost uniformly and a medium diameter tubular body 2 and large diameter tubular body 3 which are short-scaled than the small diameter tubular body 1 and made of the fluororesin are outserted on both the end parts. Joining among the small diameter tubular bodies 1, that between the small diameter tubular body and medium diameter tubular body 2 and that between the medium diameter tubular body 2 and large diameter tubular body 3 are performed on both end parts through hot fusing of fluororesin powdery body 5. The medium and large diameter tubular bodies 2, 3 possessing heat shrinkability are used, the tubular bodies are joined to each other through heat shrinking force of those and hot fusibilities of the fluororesin powdery body 5 and they are joinable reliably and easily even in case when the small diameter tubular bodies 1 are large in number. Then the small diameter tubular bodies 1 are double coated with the medium and large diameter tubular bodies 2, 3 at the joining part and strength and durability become high and favorable respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a fluororesin article having a joint.

(Prior art) For example, a heat exchange element in a heat exchanger or a deaeration element in a deaerator that removes dissolved gas in a solution is an article in which a large diameter tubular body and a large number of small diameter tubular bodies are joined together. Sometimes.

As a method for manufacturing such a bonded article, a method described in Japanese Patent Application Laid-Open No. 62-21524 is known. This method involves aligning a large number of thermoplastic resin tubes, inserting the end portions of the aligned tube bundle into a sleeve made of the same material, and applying heat treatment and a pressure difference treatment between the inside and outside of one tube. A method for welding a tube and a sleeve in a watertight state, wherein the sleeve has an inner surface surrounding the tube bundle having a tapered conical surface portion that expands in anticipation of the amount of inner diameter shrinkage due to heat treatment. It uses the same thing.

(Problem to be Solved by the Invention) In the above conventional method, it is necessary to use a sleeve having a conical surface, but there is a problem that such irregularly shaped sleeves are not necessarily easy to manufacture. Ta.

In order to solve the problem caused by the use of irregularly shaped sleeves, the applicant first fitted a large diameter tubular body made of heat-shrinkable fluororesin onto a small diameter tubular body made of fluororesin, and A heat-resistant core with an outer diameter approximately the same as the inner diameter of the body is placed inside the body, and a powdered mallet having a heat a antecedent is placed inside the extrapolated portion, and then the large-diameter tubular body is heat-shrinked. We also proposed a method (Japanese Patent Application No. 1982-2182 CJO) in which the fluororesin powder is heated to a temperature at which it can be thermally fused, and the tubular bodies are joined to each other to obtain a joined article.

This method does not require the use of irregularly shaped sleeves.
This is preferred because a II fissure bonded article can be easily obtained.

However, with this method, when the number of small-diameter tubular bodies used increases, bubbles may remain in the fused part due to the fluororesin powder, resulting in concerns about bonding strength and liquid tightness. There is.

Accordingly, the present invention is a further improvement on the previous proposal by the present applicant, and aims to provide a joined article that does not use an irregularly shaped sleeve and does not generate bubbles at the welded portion.

(Means for Solving the Problem) As a result of various studies, the inventor has found that although the reason is not clear,
The inventors have discovered that the above object can be achieved by fitting both the medium and large diameter tubular bodies onto the small diameter tubular body, leading to the present invention.

That is, the fluororesin bonded article according to the present invention has l! ! ,
On both ends of several small-diameter tubular bodies made of fluororesin, medium-diameter and large-diameter tubular bodies made of resin are inserted, and at the ends, the small-diameter tubular bodies mutually It is characterized in that a small-diameter tubular body and a medium-diameter tubular body, and a medium-diameter tubular body and a large-diameter tubular body are joined.

Furthermore, the method for manufacturing the fluororesin bonded article according to the present invention includes:
Heat-shrinkable medium-diameter and large-diameter fluororesin tubular bodies are fitted onto at least one end of a plurality of small-diameter fluororesin tubular bodies, and the small-diameter tubular bodies have a diameter approximately the same as that of the inner diameter. A heat-resistant core body having an outer diameter of the same size is disposed, and a fluororesin powder having heat-sealing properties is disposed on the outer circumferential surface of the end portions of these small-diameter tubular bodies, and then a heat-resistant core body having an outer diameter of The end portions are joined by heating to a temperature at which the fluororesin powder is thermally shrunk and the fluororesin powder is thermally fused.

Hereinafter, the present invention will be described in detail with reference to the drawings. In FIG. 1, 1 is polytetrafluoroethylene (P'
rFE), tetrafluoroethylene-perfluoroalkyl vinyl ether co-ffi (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoro It is a small diameter tubular body made of a fluororesin such as propylene-perfluorovinyl ether copolymer (EPE).

Although the number of small-diameter tubular bodies is two in the illustration, it is not limited to this and may be three or more, but the present invention is particularly useful when there are a large number of small-diameter tubular bodies (for example, about 80 or more). It is. A heat-shrinkable medium-diameter tubular body 2 and a large-diameter tubular body 3 (both of which have a heat shrinkage rate of (usually 100-400%) is extrapolated.

Inside each small-diameter tubular body 1, a rod-shaped or cylindrical heat-resistant core body having an outer diameter approximately the same as the inner diameter thereof is placed inside the end portion of which the medium-diameter and large-diameter tubular bodies 2 and 3 are inserted. 4 is placed.

This core body 4 is used to prevent deformation of the small diameter tubular body 1 when the heat shrinkage force of the medium diameter and large diameter tubular bodies 2 and 3 acts on the small diameter tubular body 1 in the heating process to be performed later. Use a material that does not deform at the temperature at which the heating process is performed.

As described above, the heat-resistant core 4 serves to maintain the shape of the small-diameter tubular body 1 during the heating process, and its length (CDI) is the length of the core body 4 that maintains the shape of the small-diameter tubular body 1.
It is preferable to make the length longer than the extrapolated length (D'2 or D3).

Therefore, a core body that is equal to or longer than the small diameter tubular body 1 can be disposed within the small diameter tubular body 1.

This core body 3 may be used by coating the outer peripheral surface with a mold release agent such as silicone resin.

In addition, in the method of the present invention, in order to join the small diameter tubular bodies 1 to each other and to join the small diameter tubular body 1 and the medium diameter tubular body 2, heat fusion is applied on the outer circumferential surface of the end of the small diameter tubular body 1. A fluorine eye oil powder 5 having properties is disposed. Specific examples of these fluororesins include PFA, FEP, ETFE%EPE
etc. can be mentioned.

The particle size of this powder is set depending on the type of fluororesin, the temperature during heating, etc., but is usually about 50 am or less. The length (D4) of this powder placement area is preferably shorter than the extrapolated lengths (D2, D3) in consideration of thermal flow during heating. If (D4) is too long, hot melt a-
The fluororesin flows greatly and the end of the small diameter tubular body 1 (
For example, there is a concern that the liquid may flow into the interior from the left end in the drawing.

In addition, in the present invention, as shown in the figure, the fluorine sebum powder 5 can also be placed on the outer peripheral surface of the end of the medium-diameter tubular body 2, if desired. With this arrangement, the bonding strength between the medium diameter tubular body 2 and the large diameter tubular body 3 can be further improved.

In the present invention, the small-diameter tubular body 1, the medium-diameter tubular body 2, the large-diameter tubular body 3, the heat-resistant core 4, and the fluorine sebum powder 5 are arranged as described above and then heated. The heating at the cutting edge can be performed, for example, by a heater 6 placed on the large diameter tubular body 3. The temperature at this time is not limited to a temperature (above the softening temperature or above the melting point) at which the medium and large diameter tubular bodies 2 and 3 can be thermally shrunk and the fluororesin powder 5 can be thermally fused.

By this heating, the heated regions of the medium diameter and large diameter tubular bodies 2.3 undergo thermal contraction, and the fluororesin powder 5 softens or melts, exhibiting the antecedent to heat 8.

Therefore, the medium-diameter tubular body 2, the small-diameter tubular body l, and the small-diameter tubular body 1
They are fused together by the fluororesin powder 5 while being subjected to thermal shrinkage force, and the medium diameter tubular body 2 and the large diameter award body 3 are also joined at their ends.

Although the above shows an example of joining at one end of the small-diameter tubular body, in the present invention, both ends of the small-diameter tubular body can be joined simultaneously or sequentially. When joining is performed at both ends of the small-diameter tubular body, a long product having approximately the same length as the small-diameter tubular body can be used as the medium-diameter tubular body and/or the large-diameter tubular body. If the medium-diameter tubular body or large-diameter tubular body is a long product, the tubular body may have one-sided heat absorption over its entire length, or it may be heat-shrinkable only at the ends to be joined. It may be.

FIGS. 2 and 3 show the structure of the fluororesin bonded article according to the present invention, in which both ends of a plurality of small-diameter tubular bodies 1 with fluorine-faced fat fissures are substantially aligned; A medium-diameter tubular body 2 and a large-diameter tubular body 3 made of fluororesin, which are shorter than the small-diameter tubular body 1, are inserted onto the top. At both ends, the small diameter tubular bodies 1, the small diameter tubular bodies 1 and the medium diameter tubular bodies 2, and the medium diameter tubular bodies 2 and the large diameter tubular bodies 3 are joined by heat fusion using fluororesin powder 5. .

(Example 1) Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example: PTFE with an inner diameter of 0.5 wm, an outer diameter of 0.8 wm, and a length of 1 m.
100 small diameter tubular bodies were prepared, and one end of these small diameter tubular bodies was made of PTFE with an inner diameter of 11 m, an outer diameter of 12 =, and a length of 31 m.
A heat-shrinkable medium-diameter tubular body consisting of (#4 shrinkage rate 220%,
Heat shrinkage temperature: 350°C) and inner diameter: 14mm, outer diameter: 161mm
A heat-shrinkable large-diameter tubular body made of PTFE with a length of I11 (heat shrinkage rate of 160%, heat loss d temperature of 350° C.) is extrapolated.

Further, inside each of the small diameter tubular bodies, a round rod-shaped iron core body with an outer diameter of 0.48 mm and a length of IOC* is placed between the large diameter tubular body and the medium diameter tubular body, and between the medium diameter tubular body and the small diameter tubular body. PFA powder with a particle size of approximately 30 μm (melting point 305
°C), and a heater is placed on the outside of each large-diameter tubular body. The length (D4) of the PFA powder placement area is approximately 51
shall be. These small diameter tubular bodies, medium diameter tubular bodies, core bodies, PFA
The arrangement of the dresser and heater is the same as shown in FIG.

Next, after heating with one heater at a temperature of 380° C. for 10 minutes, the heater and core were removed to obtain a PTFE bonded article.

The joint structure of this joined article is the same as that shown in Fig. 2, and the heat between the small diameter tubular bodies, the small diameter tubular body and the medium diameter tubular body, the medium diameter tubular body and the large diameter tubular body, and the They are joined by fusion.

The joint of this article was cut and the part where the PFA powder was applied was visually inspected, but no air bubbles were observed.

In addition, in order to check the airtightness at the joint of this article, the opening at one end of the large-diameter tubular body was tightly plugged, and a pressure of 5 kP was applied from the opening at the other end.
/d of pressurized air was introduced, and air leakage was visually observed. As a result, no air leakage was observed. In addition,
At this time, the joint was held in water and observed.

(Effects of the Invention) In the method of the present invention, medium-diameter and large-diameter bodies with heat-shrinkability are used, and the 'g-shaped body' moves due to their heat-shrinkage force and the heat-fusibility of the fluororesin powder. Since they are arranged so that they are joined together, even when there are a large number of small-diameter tubular bodies, the joining operation can be performed reliably and easily. In addition, the joined article obtained by the present invention has a small diameter tubular body double corrugated by a medium diameter tubular body and a large diameter tubular body at the joint part, and has high strength.
(It has good durability.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway sectional view showing an example of a method for manufacturing a bonded article made of fluororesin according to the present invention, and FIGS. 2 and 3 are front and side views showing examples of a bonded article according to the present invention. . 1... Small diameter tubular body 2... Medium diameter tubular body 3... Large diameter tubular body 4... Heat resistant core body 5... Fluororesin powder

Claims (2)

[Claims] (1) A medium diameter and a large diameter tubular body made of fluororesin are fitted onto at least one end of a plurality of small diameter tubular bodies made of fluororesin. A joined article made of fluororesin, characterized in that a body and a medium-diameter tubular body, and a medium-diameter tubular body and a large-diameter tubular body are joined. (2) On at least one end of a plurality of small-diameter fluororesin tubular bodies, heat-shrinkable medium-diameter and large-diameter fluororesin tubular bodies are inserted, and the inner diameter of the small-diameter tubular bodies is A heat-resistant core body having an outer diameter of approximately the same size as that of the medium-diameter and large-diameter tubes is disposed, and a fluororesin powder having heat-sealing properties is disposed on the outer circumferential surface of the ends of these small-diameter tubular bodies. A method for producing a joined article made of fluororesin, characterized in that the end portions are joined by heating to a temperature at which the diameter tubular body is thermally shrunk and the fluororesin powder is thermally fused.