JPS6159272B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an inorganic material-coated synthetic resin pipe suitable for water supply and drainage, hot water pipes, ventilation pipes, etc.

Iron pipes, hard vinyl chloride resin pipes, and the like are mainly used as water supply and drainage pipes, hot water pipes, and ventilation pipes installed in buildings such as houses and schools. However, iron pipes have the drawbacks of being difficult to protect against internal corrosion, being heavy, and prone to condensation on the outer surface, so synthetic resin pipes such as hard vinyl chloride pipes are widely used. Although these hard vinyl chloride pipes are generally low in corrosion, lightweight, and have excellent workability, their fatal drawbacks are that they lack fire resistance and have lower mechanical strength such as impact strength than iron pipes.

In addition, although this can be said to be common with iron pipes, it also has the drawback of making large noises during drainage, etc. As a countermeasure to this problem, a coated pipe body in which the outer peripheral surface of the synthetic resin pipe is coated with an asbestos-cement material has been proposed. .
This coated tube body has the advantage of increasing mechanical strength and improving fire resistance, but the disadvantage is that the coating layer has poor elasticity and the inner synthetic resin tube expands.
It cannot keep up with shrinkage and bending and cracks are likely to occur. In addition, the weight increases, making handling difficult and making cutting difficult. Furthermore, since asbestos is used, there is a problem in terms of sanitary control of asbestos dust generated during manufacturing of the sheathed tube body and cutting work during piping.

The present invention aims to improve the drawbacks of conventional asbestos-cement coatings while taking advantage of the features of the above-mentioned coated synthetic resin pipes. In other words, the outer peripheral surface of synthetic resin pipes, which have excellent corrosion resistance and excellent workability, is coated with a special inorganic coating material to improve fire resistance and mechanical strength, as well as the light weight that synthetic resin pipes inherently have.
It is an object of the present invention to provide a method for manufacturing a coated synthetic resin pipe body that does not significantly impair features such as excellent workability as in the case of asbestos-cement coatings.
Another important object of the present invention is to provide a method for producing a coated synthetic resin pipe in which cracks do not occur in the coating layer even when the synthetic resin pipe expands and contracts due to temperature.

Another object of the present invention is to provide a method for manufacturing coated synthetic resin pipes that does not require the use of asbestos, which is harmful to the human body.

For these purposes, the inventors conducted a series of detailed and extensive experiments using various binding materials, lightweight aggregates, and reinforcing materials. The inventors have now completed the present invention by discovering that when the outer circumferential surface of a synthetic resin pipe is coated with a mixture of the cement material and water used in the above, good performance meeting the object of the present invention can be obtained. That is, the gist of the present invention is that the outer peripheral surface of the synthetic resin pipe is made of 100 parts by weight of a cement material, a lightweight aggregate consisting of 100 parts by weight of a cement substance, calcined vermiculite and perlite, and having a weight ratio of calcined vermiculite to pearlite in the range of 3 to 0.1. The present invention provides a method for producing a coated tube body, which is coated with a kneaded material consisting of 100 parts by weight and water and cured to form a single body.

The present invention will be explained in detail below.

In the construction industry, it is common practice to use calcined vermiculite as an aggregate in cement materials as a way to reduce the weight and improve the fire resistance of cement concrete. Therefore, the present inventors added calcined vermiculite in various ratios to the cement material and used the mixture with water as a coating material for synthetic resin pipes such as hard vinyl chloride resin pipes to make a prototype coated synthetic resin pipe. . The coated synthetic resin pipes made in this way were much lighter than asbestos-cement-based coated synthetic resin pipes, and were easier to cut and cut. could not follow the expansion of the synthetic resin pipe, and cracks occurred.

On the other hand, perlite is also a material commonly used as a lightweight aggregate in the construction industry, but the present inventors mixed it with cement material and used the hydrated product with water as a coating material to fabricate a coated synthetic resin pipe. is much lighter than synthetic resin pipes coated with asbestos-cement materials, and even in crack initiation tests in which hot fluids such as boiling water are passed through the pipes, it is relatively stable, although it does not have the ability to follow expansion and contraction due to heat. However, in this case, there were some difficulties in processing, such as difficulty in cutting.

As described above, even if pearlite or calcined vermiculite were used alone as a cement material as a coating material, the coated synthetic resin pipe which is the object of the present invention could not be obtained.

Therefore, the present inventors thought of using a combination of calcined vermiculite and pearlite, which are each effective in improving the workability of the coating layer and preventing cracks, and by changing the ratio of both, the coating synthetic resin pipe combined with cement material was further developed. We made a number of prototypes and conducted performance tests. As a result, unexpectedly, when the ratio of both is within a certain range, performance in both workability and crack prevention exceeds that when each is used alone, leading to the present invention.
Furthermore, a combined effect was observed in terms of fire resistance, and superior performance was observed compared to when each was used alone.

Examples of cement materials used in the present invention include materials that harden through hydration reactions, such as gypsum, Portland cement, slag cement, silica cement, flyash cement, alumina cement, and high sulfate cement (jet cement). , or a mixture of these may be used if necessary. Furthermore, it is also possible to use commonly used coagulation regulators, dispersants, and water reducing agents.

The calcined vermiculite used in the present invention is one obtained by rapidly heating vermiculite to release water between crystal layers and expand it into an accordion shape. specific gravity
It is extremely lightweight with a weight of about 0.5 to 0.05, and has excellent properties of heat insulation, fire resistance, and elasticity. Pearlite is a foamed spherical body whose main component is vitreous silicic acid, and is often used as a lightweight aggregate. The raw stones are obsidian, nacre, rosinite, quartz trachyte, etc. All of these stones are made by rapid heating, causing the water they contain to scatter and release, forming hollow particles with a specific gravity of 0.7 to 0.05. That's about it.

In the present invention, if the weight ratio of calcined vermiculite to pearlite is greater than 3, the overall performance will be poor as described above, and in particular crack prevention will be insufficient.

Further, if this ratio is less than 0.1, there will be an adverse effect that cutting processing will be particularly difficult. On the other hand, the amount of this mixed lightweight aggregate added to the cement material is
10 to 100 parts by weight is appropriate for 100 parts by weight.
If the amount is less than 1 part by weight, the purpose of weight reduction will not be achieved and the fire resistance will not be sufficiently exhibited. Moreover, if it exceeds 100 parts by weight, the mechanical strength of the coating layer itself becomes unsatisfactory for the purpose.

Although the sheathed tube body of the present invention has practically sufficient crack prevention and mechanical strength, various fiber reinforcing materials, nets, and cloths may be used to further improve these properties. Fiber materials include asbestos pine, rock wool, glass fiber, steel fiber, wood wool,
Examples include cellulose fibers, flea fibers, various synthetic fibers, ceramic fibers, and carbon fibers.

In the present invention, the coated tube can be allowed to stand at room temperature to allow the hydration reaction of the cement material to proceed and harden and integrate, but if necessary, it can be heated at a temperature below the softening point of the synthetic resin tube as described above. It is also possible to shorten the curing reaction time. At this time, it is preferable to maintain a humid air condition for the cement material hydration reaction.

The cladding body of the present invention manufactured in this way is lightweight, has excellent fire resistance and workability, and does not crack even when high-temperature fluid is passed through it, and is used in buildings such as houses, schools, general offices, etc. Useful as piping for specific purposes.

The coated pipe body of the present invention also exhibits excellent performance in terms of dew condensation prevention and sound absorption, which are not found in conventional piping.

The coated tube body of the present invention is also preferable from the standpoint of environmental hygiene because it does not require the use of asbestos.

Next, the present invention will be explained in more detail according to Examples.

Example 1 Portland cement, calcined vermiculite,
Mixing pearlite at a weight ratio of 5:1:3,
The outer diameter of the water-kneaded mixture is 80 mm.
It was attached so that it was mm. Then 40℃100%RH
The coated hardened cementitious material was cured for 24 hours in a humid air and then at room temperature for 3 days without evaporating water.
Next, it was made into a product after being naturally dried. The bulk specific gravity of the coating layer is
1.1 The bending strength was 40Kg/ ^cm2 . Hot water at 90°C was passed through the inside of this cladding tube once for 15 minutes, but no abnormality was observed on the cladding surface. In the case of asbestos-covered pipes, a hot water test under the same conditions revealed cracks in various places in the coating layer.

Example 2 A kneaded product prepared by mixing Portland cement, calcined vermiculite, and pearlite in a weight ratio of 10:1:2 and kneading with water was applied to the outer peripheral surface of a thin-walled hard vinyl chloride pipe (outer diameter 60 mm and thickness 2 mm) as in Example 1. A coated pipe body was prepared by adhering, curing, and drying under the same conditions, and the bulk specific gravity of the coated layer was 1.3 and the bending strength was 64 kg/cm ² .

Hot water at 90°C was passed through the inside of the cladding once for 15 minutes, but no abnormality was observed on the surface of the cladding. Furthermore, cutting the coated tube body was also easy with an ALC saw.

The fire resistance of the cladding body obtained in this way is
This was done in accordance with JISA1304. That is, heating was performed for 2 hours along a prescribed temperature curve, and after cooling, the cladding tube was taken out. Although the hard PVC pipe had melted, there were no major cracks in the coating layer, only a small amount of hair cracks, and it retained its original shape, and the coating material maintained sufficient strength to be used as a pipe. It was confirmed that the material had sufficient fire resistance.

Claims (1)

[Claims] 1. The outer peripheral surface of the synthetic resin pipe is made of 100 parts by weight of a cement substance, 10 to 100 parts by weight of lightweight aggregate consisting of calcined vermiculite and pearlite, with a weight ratio of calcined vermiculite to pearlite in the range of 3 to 0.1, and water. 1. A method for manufacturing a coated tube, which comprises coating the tube with a kneaded material and curing it into one piece.