JPS6014207B2 - Method for manufacturing polyvinyl acetal sponge roll - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyvinyl acetal (hereinafter abbreviated as PVAt) sponge roll used for removing and adding moisture and solvents.

Conventional sponge rolls are made by inserting a separately formed PVAt sponge tube into a shaft or bushing and fixing it using rubber or vinyl acetate adhesive.
VAt sponge tube is better than shaft or bushing)
Since the adhesive is applied to the inner lining and inserted into the shaft or bushing, the adhesive is pushed out, often resulting in poor adhesion, and insertion requires special techniques and skill. If this is done, the inserted PVAt sponge will be distorted in the direction of the ball, and as a result, the surface of the sponge cylinder will have wavy irregularities, which will affect the removal and addition of moisture and solvent. was significantly inferior.

In view of the current situation, the present inventor has conducted various studies and found that by utilizing the properties of PVAt, which becomes hard when dry and flexible when immersed in water, it is possible to insert a shaft or bushing into a PVAt sponge tube very easily. The present invention has completed a method for manufacturing a uniform PVAt sponge roll without causing adhesion failure, and without causing the PVAt sponge to be uneven in the rutting direction or twisted, and thus having no wavy irregularities on the surface of the sponge roll.

In the present invention, a split mold having an outer diameter slightly larger than the outer diameter of the shaft or pushing is inserted into a dry PVAt sponge cylinder having an inner diameter slightly smaller than the outer diameter of the shaft or pushing, and after drying, the split mold is removed. A dry PVAt sponge tube is obtained by this, and then a shaft or bushing coated with an underwater curing adhesive on the outer circumferential surface is inserted into the inner diameter of the dry PVAt sponge tube, and the PVAt sponge tube is immersed in water to shrink the PVAt sponge tube. This method of manufacturing a PVAt sponge roll is characterized in that the shaft or pushing and the PVAt sponge cylinder are fixed by curing the adhesive at the same time.

Embodiments of the present invention will be described in detail below based on the drawings.

The PVAt sponge tube used in the present invention is manufactured using a normal manufacturing method, and the inner diameter of the PVAt sponge tube is slightly smaller than the outer diameter of the shaft or bushing to be bonded.
For example, let's assume that the diameter is 3 cm/m smaller. Next, split molds with a diameter slightly larger than the shaft or pusher, for example, split molds 1, 2, and 3 with a diameter of 3 m/large as shown in Figure 1.
is inserted into the inner diameter of a dry PVAt sponge cylinder and dried in a normal dryer at a temperature of 50 to 6030. The dried state is shown in Figure 2a. When this split mold is pulled out, the inner diameter of the PVAt sponge cylinder as shown in Fig. 2b is 3w/larger than the outer diameter of the shaft or bushing.
Obtain a VAt sponge tube. The reason why the inner diameter of the PVAt sponge cylinder is made smaller than that of the shaft or pushing is to make it fit more closely to the shaft or pushing.

When drying a PVAt sponge cylinder, the reason why a split mold is used for the inner flanges is to prevent the PVAt sponge cylinder from shrinking as it dries.
This is because the plating pressure is so strong that a single mold cannot be pulled out.

The split mold is divided into three parts: outer molds 2 and 3, and middle mold 1, and it is desirable that the end of the middle mold is provided with a hole 4 so as to protrude beyond the outer diameter so that it can be easily pulled out. First, pull out the middle mold and pull out the outer mold, bringing it to the center. The purpose of drying the PVAt sponge tube is to maintain an inner lining that is 3 cm larger than the outer diameter of the shaft or bushing.When inserting the shaft or pusher into the PVAt sponge tube, the adhesive applied to the shaft or bushing This is to avoid contact with it as much as possible.

Next, as shown in Fig. 3a, an underwater curing adhesive 8 is applied to the shaft or bushing 7, and it is inserted into the inner diameter part 6 of the dry PVAt sponge cylinder 5, and then soaked in water at 20 to 5,000 ml. . As shown in Figure 3b, the PVAt sponge tube expands and contracts far, its inner diameter becomes smaller, and it comes into close contact with the adhesive on the shaft or bushing, and at the same time the adhesive hardens, and the PVAt sponge tube and shaft or bushing are bonded together. A strongly bonded PVAt sponge roll of the present invention is obtained. When the PVAt sponge roll according to the present invention is used as a shaft, it is directly fixed, and when it is used as pushing, it is fixed to the shaft by an appropriate method, and then
Just attach it to the machine concerned.

The shaft or bushing may be made of metal or plastic, and the shaft or bushing may be pretreated to improve adhesion. The adhesive used in the present invention is an epoxy-based or urethane-based underwater curing type adhesive depending on its curing characteristics and adhesive strength. When stronger adhesive strength is required, an epoxy adhesive is preferred.

This is to allow the PVAt sponge to adhere while maintaining its swollen state in water. In addition, when forming an adhesive layer on the shaft or bushing, a large amount of adhesive is applied to the shaft or bushing, so PV
There is a risk that the adhesive will be partially impregnated into the At sponge and the sponge will become partially hard, and the viscosity of the adhesive will decrease because it is cured in 20 to 50 q0 water, causing the adhesive liquid to drip and become uneven. If adhesion occurs, wrap cotton cloth, vinylon non-woven cloth, etc. around the shaft or pusher.
Uniform and strong adhesion can be obtained by applying the adhesive to this, inserting it into the dry PVAt sponge and curing it.

Furthermore, if the shaft or bushing is wrapped with stainless steel wire or silk and coated with adhesive, it is possible to prevent the sponge from moving toward the mouse. Since the present invention has the above configuration, it has the following effects.

In the present invention, the adhesive is applied uniformly to the shaft or bushing, and then it is inserted into a PVAt sponge cylinder whose inner diameter is larger than the outer diameter of the shaft or bushing, and then fixed. Alternatively, there is no fear that the adhesive will be scraped off when pushing into the bushing, and even a long PVAt sponge can be easily and uniformly bonded to the PVAt sponge and the shaft or bushing.

In addition, in the present invention, by immersing a dry PVAt sponge cylinder in water, the PVAt sponge cylinder absorbs water and swells, and is bonded while returning to the shape at the end of the PVAt formalization reaction. Unlike conventional PVAt sponges that are pressed and glued into shafts or bushings, there is no axial spacing, twisting, or surface unevenness, and it is easy to obtain a material with an outer peripheral surface similar to that of an integrally molded PVAt sponge.
A PVAt sponge roll with excellent solvent removal and application effects can be obtained.

[Brief explanation of the drawing]

FIGS. 1a and 1b are top views of the split mold used in the present invention, and FIG. 1 c is a partial perspective view of the split mold. In Figure 2 a, insert the split mold into the PVAt sponge tube,
It is in a dry state, and b is the result of pulling out the split mold. Figure 3a shows the PVAt sponge cylinder and shaft before being immersed in water, and b shows the PVAt sponge roll of the present invention immersed in water. 1, 2, 3, 4... split mold, 5...
...PVAt sponge cylinder inner diameter part, 6...P
VAt sponge cylinder inner diameter, 7...Shaft or bushing, 8...Adhesive. ``Zukyu 2 Gummy Figure

Claims (1)

[Claims] 1. By inserting a split mold having an outer diameter slightly larger than the outer diameter of the shaft or bushing into an undried polyvinyl acetal sponge cylinder having an inner diameter slightly smaller than the outer diameter of the shaft or bushing, and removing the split mold after drying. Obtain a dry polyvinyl acetal sponge tube,
Next, a shaft or bushing coated with an underwater curing adhesive on its outer circumferential surface is inserted into the inner diameter of the dried polyvinyl acetal sponge tube, and immersed in water to shrink the polyvinyl acetal sponge tube and at the same time harden the adhesive. A method for producing a polyvinyl acetal sponge roll, comprising the step of firmly fixing a shaft or a bushing to a polyvinyl acetal sponge cylinder.