JPS597017A - Method of masking pipe end and masking tape - Google Patents

Abstract

PURPOSE:To make it easy to perform the operation of treatment of a pipe end without affecting corrosion resistance, by winding, around the outer circumference of the pipe end of a metal pipe, a masking tape consisting of a resin highly affinitive for a synthetic resin, before the outer surface of the metal pipe is coated with the resin. CONSTITUTION:When it is required to coat the outer surface of the metal pipe with a synthetic resin (e.g. PE, etc.), the making tape 5 that has approximately the same length as the outer circumference of the metal pipe 1 and has been applied with an adhesive (e.g. a high temperature type adhesive such as PE copolymers, etc.) for the metal pipe 1 is wound previously around the pipe end of the metal pipe 1 that may have been heated if required. It is advantageous that such several masking tapes 5 are wound with them sandwiched between separators 6. EFFECT:The operation can be automated and the peeled coating resin can be reused.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tube end masking method for sealing the outer circumference of a metal tube end before coating the outer circumference with a synthetic resin, and a masking tape used in this method.

Since both ends of the outer resin-coated metal tube are welded, it is necessary to remove the resin at the ends.

However, the resin coated on the outer periphery of the metal tube cannot be easily made into III #fE. This is clear from the fact that the main focus of the resin coating is how to firmly adhere the resin to the metal tube.

On the other hand, the outer resin-coated metal tube is manufactured by a so-called resin extrusion method such as the T-die method or the round die method. This is the reason why the resin coating is applied continuously. However, it is also impossible to stop coating only the tube ends with resin.

For this reason, in the production of externally resin-coated metal tubes, before coating the outer periphery of the metal tube with synthetic resin, it is necessary to
As shown in a), the tube end of the metal tube (1) is sealed with a masking material (2) such as glass fiber tape, heat-resistant paper tape, or a release agent (for example, silicone), and then resin coating is performed from that point. As shown in Fig. 1 (l), a slit (3) is made in the tube circumferential direction at the end of the tube, and the coating resin (4) is made on the outside.
2 along with the masking interest (2). However, conventional masking materials (2) such as glass fiber tape, heat-resistant paper tape, and release agents are so-called foreign substances when viewed from the coating resin.

This kind of foreign matter or the coating resin (4) inside the slit (3)
), it becomes a starting point for rusting and significantly deteriorates the corrosion resistance of the outer resin-coated metal pipe. ) is removed, a portion of the remaining coating resin (4,) is scraped off, but this naturally takes time and effort, and even if this is removed, there is a risk of contamination by foreign matter. In view of the above, the present invention provides a tube end masking method that does not pose the risk of deteriorating the surface corrosion of a resin-coated metal tube on the outside even if masking material remains on the coating resin inside the slit, and The present invention aims to provide a masking tape, and its most significant feature is that the tape used as the masking material is a resin tape made of a material that has a high affinity for the coating resin.

The present invention will be explained in detail below.

In the present invention, the material with high affinity for the coating resin is:
It refers to a material that has similar properties to the coating resin, does not become a foreign substance in the coating resin, and is integrated with the coating resin when kneaded. For example, polyolefin resin is used as opposed to polyethylene.

The basic concept for conventional masking materials is their releasability to metal pipes. On the other hand, as described above, the main focus of the coating resin is on its adhesion to the metal tube. Once upon a time,
It has been thought that the masking material (like it or not) must be foreign to the coating resin. In short, the masking material does not need to be a foreign substance to the coating resin, but should be of the same type as possible if it can be peeled off from the metal pipe. If the same type of masking material is used, even if the masking material were to remain on the coating resin inside the slit, there would be no risk of deteriorating the corrosion resistance of the resin-coated metal tube on the outside, and this would prevent the tube end from being damaged. This not only simplifies the process of stripping off the coating resin on the parts, but also allows the peeled off coating resin to be reused together with the masking material.The present invention was made based on this idea, and the masking By using a resin tape made of a material that has a high affinity for the coating resin, we can prevent deterioration of the corrosion resistance of the outer resin-coated metal pipe due to residual masking material.
d. (1) As a result of making the removal work of the remaining material unreasonable or extremely simple, the pipe end treatment work after resin capping becomes easy and automation thereof becomes possible. ■The benefits are great, such as making it possible to reuse the coating resin that has been peeled off, since it becomes a masking material or a cover resin.

In other words, regarding the reuse of the coating resin in (2), conventionally foreign matter would adhere to the peeled coating resin, so reuse was unnecessary unless it was to be used for lower-grade products, but in the present invention. Even if it gets mixed into the masking tape or the coating resin, there will be no problem, so it becomes possible to reuse the coating resin that has been removed, regardless of whether it is a low-grade product or a high-grade product.

Hereinafter, the present invention will be explained in detail by taking as an example the case where the coating resin is polyethylene, a masking material, or a polyolefin resin tape.

Figure 2 (a) i, J: Masking tape to be used (5
) is inside. What is the material of the masking tape (5)?
As you can see, it is a polyolefin resin. This [s1
It is clear that this resin has a high affinity for polyethylene, which is a coating resin, since this resin is used as an adhesive agent when coating polyethylene. This polyolefin resin may be a polar polyolefin resin whose polar groups have been adjusted in order to give the masking tape (5) itself some adhesive strength (approximately 5 kgAM). Examples of known polyolefin resins include modified polyethylene.

The length of the masking tape (5) described in - is approximately the same as the circumference of the metal tube to be coated with resin, and 1J is the same as or greater than the length of the end of the tube from which the coating resin is to be removed. Leave it slightly larger. There are no particular restrictions on the thickness, but masking tape (5.5
), in order to prevent it from curling due to this heat, it is best to wrap it around 5 mm or more.

-1- The masking tape (5) 1 should be coated with adhesive in the - direction in order to securely wrap it around the metal tube. In this way, the paint part is limited to both ends of the masking tape (5) to save adhesive, and at the same time, the masking tape (5) is peeled off.
Can you make a easier? Even if there is adhesive only at both ends, if the masking tape (5) is wrapped around the metal tube while being stretched in the longitudinal direction, the masking tape (5)
5) Situation Q can be prevented if the masking tape (5) tightly adheres to the outer periphery of the end of the metal tube (1) and falls off due to contact with the conveying roller. This effect is particularly remarkable in the case of masking tape (5) or a polar polyolefin resin that itself has some degree of adhesiveness. When wrapping the masking tape (5) around a preheated metal tube, use a high-temperature adhesive such as a copolymer (polyethylene copolymer) that exhibits good adhesion near the preheating temperature. Should I use a drug?

FIG. 2 (1)) shows a plurality of masking tapes (5) sandwiched between separators (6) (6) in order and wound. Doing so not only improves the portability and usability of the masking tape (5), but also is particularly advantageous in the case of automatic winding, which will be described later.

Next, an example of the masking tape (5) for one car will be explained with reference to FIG. The masking tape (5) is made of polar polyolefin resin, has a high-temperature adhesive on both ends of its negative side, and has a plurality of pieces as shown in Figure 2 (1)). It is wrapped around and held in between.

In this usage example, first, about 15Q for resin coating.
While rotating the metal tube (1), which has been preheated to more than 'c, in the circumferential direction as shown in Fig. 3 (ω), the masking tape (5) shown in Fig. 2 (Ij) attached to the reel (7) is fed out. Hold the adhesive part at the tip of the roller (8)
Crimp the outer periphery of the tube end. The masking tape (5) with its tip attached to the outer periphery of the tube end is wrapped around the outer periphery of the tube end without being tensed in the longitudinal direction due to the rotational force of the metal tube (1) and the restriction by the presser roller (8). When the metal tube (1) has made approximately one rotation from the start of winding, it reaches the tail end or the outer periphery of the tube end, and is automatically crimped by the presser roller (8) to complete the winding. Separators (6) (6) are reels (9) (9)
is automatically wound up. The wrapped metal tube (1) is moved in the axial direction, a masking tape (5) is wrapped around the outer periphery of the other tube end in the same manner as described above, and then sent to the next resin coating step.

The handling of the metal tube (1) in the resin coating process is the same as in the case of general polyethylene coating. In other words, a plurality of metal tubes (1) with masking tape (5) wrapped around them are stacked at appropriate intervals, and in the case of the F die method, these are not fed spirally, or in the case of the round die method, they are fed in a spiral manner. Rather than moving them only in the axial direction, an adhesive material is applied to the outer periphery, and then polyethylene is coated over the adhesive material. Figure 3 (b3) shows the end of the metal tube (1) coated with polyethylene.
This is shown in cross section. The masking tape (5) is wrapped so as to partially protrude to the side to prevent the coating resin (4) from adhering to the tube end. Due to this, the length of the masking tape (11) of the masking tape (5) is slightly longer than the length of the tube end from which the coating resin is to be peeled off.

When the coating resin is cooled and solidified, make a slit (5) in the circumferential direction of the partial pressure tube of the masking tape (5) as shown in Figure 3 (shown by the broken line 1), and then
), press the cutting tool θ0) against the coating resin (4I) on the outside of the slit from the side, and in this state rotate the metal tube (1) in the circumferential direction. The coating resin (4,) (polyethylene) is completely adhesively fused to the -7 skinning tape (5),
The adhesive of the masking tape (5) does not lose much of its adhesion when cold, so the coating resin (4) is removed by cutting with the cutting tool mentioned above.
) is easily peeled off from the metal tube (1) together with the masking tape (5).

Once the coating resin (4,) is stripped off, the outer edge of the coating resin inside the slit can be cut if necessary, but the masking tape (5) remains in this coating resin. However, it does not pose a major problem in terms of corrosion resistance.
2. To make cutting finishing very simple.

As an example, when manufacturing an outer resin-coated metal tube with the specifications shown in Table 1, tube end masking, resin fatigue covering, and tube end treatment were performed as shown in FIGS. 3(a) to (c). The specifications of the masking tape are listed in Table 1 - Table 2 shows the time required for tube end treatment with , and the tube end treatment time for tube end masking using conventional glass fiber tape. In comparison, the pipe end treatment in the conventional example required manual work to completely remove the remaining masking material.

In the usage example shown in Table 1, Table 2, and Figure 4, the masking tape (5) is wrapped after the metal tube (1) has been preheated. This is because the adhesive is used frequently, and if this type of adhesive is not used, winding can be carried out without worrying about preheating.

Finally, wrap the masking tape (5) and cover the resin (
It goes without saying that step 4) may be removed manually.

As is clear from the following explanation, the present invention not only prevents deterioration of the corrosion resistance of the outer resin-coated metal pipe due to residual masking material, but also eliminates the risk of deterioration of the corrosion resistance of the outer resin-coated metal pipe. Therefore, the slit position can be determined uniformly when the coating resin is stripped off, and cutting work after stripping is unnecessary or can be done very easily, so the finish of the pipe end after covering the resin limbs is improved. It has become very easy to do this, and its automation has also significantly reduced the number of steps required to finish the pipe end, in line with FJJ performance. ! ?・It is. Moreover, in the present invention, since the masking material can be the coating resin material, it is possible to reuse the peeled coating resin, and furthermore, when cutting the coating resin with a cutting tool, it is possible to prevent the foreign matter from being caught between the gabite and the outer periphery of the metal tube. Since it is not sharp, it has good machinability and does not roughen the cutting surface, resulting in a good quality finish at the end of the tube.

[Brief explanation of the drawing]

Fig. 1 (a) (+)) i, j Schematic diagram showing conventional pipe end masking and machining of the masking part, Fig. 2 (ω
(b) is a schematic diagram showing an example of the masking tape of the present invention, and Figures 3 (a) to (C) are step-by-step illustrations of an example of the process from the masking method of the present invention to the finishing of the masking part. FIG. In the figure, ■ = metal tube, 2: monthly masking, 3 nislit, 4: coating resin, 5: masking tape, 6: separator, 7: tape reel, 8: presser roller, 9: separator reel, 10: bite. In order of appearance: Sumitomo Metal Industries, Ltd. Leri, agent Patent attorney: 1□::',
(,, gourd 1..."... Figure 1 #I 1 2nd (0) #I 3 Figure. (0) 75-

Claims (2)

[Claims] (1) Pipe end masking characterized by wrapping a resin tape made of a material with high affinity for the synthetic resin around the outer periphery of the end of the metal pipe before coating the outer periphery of the metal pipe with a synthetic resin. Method. (2) A resin tape made of a material with high affinity for the synthetic resin coated on the outer periphery of the metal tube and having approximately the same length as the outer periphery, and having an adhesive for the metal tube on one side. A pipe end masking tape comprising: