JPS6325926B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin pipe lamination molding method that is used to manufacture particularly large-diameter resin pipes, and more specifically, a method in which resin is applied multiple times to the inner molding surface of a mold. The present invention relates to a resin pipe lamination molding method in which resin pipes are laminated to form a resin pipe.

Conventionally, in the production of large-diameter resin pipes, as shown in Figure 1, an operator uses a laminating roller to layer resin onto the inner molding surface 2 of a mold 1, and then takes an appropriate curing time. The resin tube 3 was formed by stacking the resin tubes several times. In this case, a resin of the same quality is used all around the circumference, and as a result, the laminated resin tends to sag. In other words, the wall thickness near the upper 45-degree direction A became thinner, and the thickness moved downward (sagging) and became thicker due to the dripped resin near the lower 45-degree direction A. This is Figure 1,
Ceiling part A, upper part B, and lower part C shown in Fig. 2
As is clear from the comparison of the effective pressure distributions between the upper part 45 degrees and the bottom part D, this is due to the fact that the effective pressure in the vicinity of the upper 45-degree direction (a) is high, and the effective pressure in the lower part 45-degree direction and the vicinity of b is low. The above-mentioned change in the wall thickness of the resin tube 3 causes non-uniformity in strength, and also causes cracks during curing and shrinkage.

An object of the present invention is to provide a method for laminated resin pipe molding that allows the wall thickness to be made uniform over the entire circumference.

In order to achieve the above object, the resin pipe lamination molding method of the present invention is such that the lower half is laminated with a resin having a normal viscosity, and the upper half is laminated with a resin having a higher viscosity than the resin on the bottom side. are layered and then layered repeatedly.

According to this method, since the resin near the upper 45 degree direction has a high viscosity, it does not move (sag) downward, and therefore the lower 45 degree direction does not become thick, and the resin is always maintained all around the circumference. The wall thickness can be made uniform.

If the curing time is too short, the resin will not be sufficiently cured, and therefore repeated lamination cannot be performed satisfactorily.
On the other hand, if the curing time is long, the styrene evaporates and hardening becomes difficult. In addition, if the thickness of the laminated resin is small, styrene will evaporate more, making it difficult to cure, and the resin will sag over a long period of time.

In order to solve such problems, another method of laminating resin pipes according to the present invention is to laminate a resin having normal viscosity in the lower half, and to laminate a resin having a normal viscosity in the upper half than the resin on the lower half side. also laminated with highly viscous resin,
Lamination is repeated with a curing time of 5 to 20 minutes.

According to this method, curing can be performed most efficiently, and the lamination work can be made more efficient.

An embodiment of the present invention will be described below with reference to FIG. That is, when resin is laminated multiple times on the inner peripheral molding surface 11 of the mold 10 to mold the resin tube 12, the lower half 13 has a normal viscosity (4 to 10 p.p.).
However, p is a unit of viscosity (poise)), and the upper half 14 is laminated with resin having a higher viscosity (10 to 100 p) than the resin on the lower half side.
The layers are repeatedly laminated with a curing time of ~20 minutes.

Note that if paraffin is placed on the inner peripheral surface of the resin tube 12 after it is molded, no aftercare is required.

[Brief explanation of the drawing]

1 and 2 show a conventional example, FIG. 1 is a front view, FIG. 2 is a graph showing effective pressure, and FIG. 3 is a front view showing an embodiment of the present invention. 10... Molding die, 11... Inner peripheral molding surface, 12...
...resin pipe, 13...lower half, 14...upper half.

Claims (1)

[Scope of Claims] 1. A resin pipe lamination molding method in which resin is laminated multiple times on the inner peripheral molding surface of a mold to form a resin pipe, wherein the lower half is coated with normal viscosity. A method for laminating resin pipes, in which resins having the same properties are laminated, a resin having a higher viscosity than the resin on the lower half side is laminated on the upper half, and this is repeatedly laminated. 2. A resin pipe lamination molding method in which a resin pipe is formed by laminating resin multiple times on the inner peripheral molding surface of a mold, in which a resin having normal viscosity is laminated in the lower half, A resin pipe lamination molding method in which a resin with a higher viscosity than the resin on the lower half is laminated on the upper half, and the resin is repeatedly laminated with a curing time of 5 to 20 minutes.