JPH0753406B2 - Method for producing rubber molded product permeable to liquid and gas - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a rubber molded product that is permeable to liquids and gases, and more specifically, general upland fields (house cultivation, open field cultivation), orchards, horticulture. Agricultural irrigation, watering, fertilizing hoses, etc.
Aeration diffuser used for aquaculture, or a filter,
The present invention relates to a method for producing a rubber molded product that requires liquid and gas permeation, such as a flowerpot.

(Prior Art) Conventionally, for example, hoses are used for irrigation watering for planting in agriculture, horticulture, and greening facilities, and these hoses have a large number of small holes formed on the peripheral wall and exude from these small holes. Or, it is formed to sprinkle water. These hoses are manufactured by forming a predetermined hose by a known manufacturing method and then forming a small hole as a post-process in the peripheral wall of the hose.

These hoses are used in various ways depending on the application. For example, in an orchard, it is used by hanging it overhead, and in greenhouse cultivation, open-air cultivation, etc., it is used by being placed on the ground or embedded in the ground.

(Problems to be Solved by the Invention) However, the conventional irrigation and sprinkling hoses have the following problems.

That is, although there are soft hose and hard hose depending on the material of these hoses, in the case of a soft hose, the hose can be wound up while being crushed, which is convenient for storage and transportation. However, a kink occurs in the soft hose. That is, since there is no self-shape holding force, kinks such as twisting and twisting occur. Further, if the residual liquid dries while being crushed, there is a problem that not only clogging will occur but also the liquid will not swell and swell even if it is passed due to the adhesive action of the residual liquid.

Furthermore, the soft hose cannot be used in the buried method, and if it is kinked, the flow rate is not constant.

On the other hand, since the soft hose is not easily deformed, there is no risk of crushing or kinking, and although it can be used in the buried method, it has a problem that it is troublesome to store and transport and it cannot be easily installed.

The present invention has been made in view of the present situation, and provides a method for producing an agricultural irrigation and sprinkler hose that has self-shape retention and does not cause kink, and also provides a rubber molded article that is permeable to other liquids and gases. It is intended to provide a manufacturing method.

(Means for Solving Problems) Therefore, the present invention has the following configuration in order to achieve the above object.

That is, 40-80 parts by weight of rubber powder of 20-80 mesh, which is subdivided by mechanical treatment, 10-30 parts by weight of vinyl resin powder of 20-80 mesh, and olefin resin powder of 20-80 mesh. 10 to 30 parts by weight and a blowing agent powder at a ratio of 0.1 to 1 part by weight to prepare a mixed powder material, and the mixed powder material is foam-molded by an extrusion molding method,
Before the product is solidified after foam molding, it is characterized in that air bubbles are communicated between the rubber powders by taking it off at a speed higher than the extrusion molding speed.

In the above structure, the rubber powder is a granular or powdery rubber obtained by mechanical treatment of vulcanized rubber such as crushing, cutting and polishing, and may be natural rubber, synthetic rubber or a blend thereof. The size of the powder is appropriately determined depending on the molded product or application, but it is 20-80
Use mesh.

The amount of the rubber powder mixed is 40 to 80 parts by weight. To increase the amount of liquid passing and ventilation, enlarge the mesh,
On the contrary, the mesh can be made smaller in order to reduce the amount of liquid passing and ventilation.

Further, it is preferable to use ethylene vinyl acetate copolymer (EVA) as the vinyl resin powder. This resin powder is used to impart flexibility (elasticity), low temperature characteristics and weather resistance to the product. The size of the powder
Make 20 to 80 mesh and mix at a ratio of 10 to 30 parts by weight.

Usually, the resin is used in the form of pellets for easy handling, but in the present invention, the resin is not used in the form of pellets, but is used in the form of powder in order to improve the dispersion with rubber powder.

In the present invention, the incompatibility between the rubber powder and the vinyl resin powder is utilized, and the rubber powder is simply compounded for imparting elasticity or as a bulking agent as is conventionally done. Not of.

That is, the incompatibility of the rubber powder of the vulcanized rubber and the vinyl resin powder means that the vulcanized rubber and the resin do not melt,
The resin utilizes the property of holding the rubber in a wrapped state. By foaming the resin layer, it is possible to maintain a predetermined shape and strength by mixing the vulcanized rubber while forming a foamed pair in which cells partitioned by a thin film are continuous.

The olefin resin powder is used as a structural adhesive for the rubber powder and vinyl resin powder. This olefin resin powder has a special functional group introduced into non-polar PE and has a property of strongly adhering to various organic and inorganic materials by thermal reaction, that is, a polar part of which is added. It is preferably a polyolefin. As such a polyolefin, for example, Admer P (trade name) manufactured by Mitsui Petrochemical Industry Co., Ltd., Frosen (trade name) manufactured by Iron and Steel Chemical Co., Ltd., and ionomer (trade name: manufactured by DuPont Mitsui Polychemical Co., Ltd.) Hilamin) etc.

These olefin resin powders have a mesh size of 20 to 80 mesh and are mixed at a ratio of 10 to 30 parts by weight.

The foaming agent powder is 0.1 to 1 part by weight.

The compounded powder material having the above structure may be compounded by a known method, that is, a tumbler or a super mixer.

Next, the manufacturing method will be described.

The present invention is characterized in that it is molded by an extrusion molding method, the take-up speed is made faster than the extrusion speed, and cracks are generated between the bubbles to make them communicate with each other.

FIG. 1 is a schematic side view for explanation showing each step of the present invention.

First, as in the case of conventional extrusion molding, the compound powder material is extrusion foam-molded by the extruder 10. The extrusion foam molding may be carried out by a known method, and the extrusion speed, the cylinder temperature of the extruder and the like are adjusted depending on the thickness of the product, the compounding ratio, the particle size of the rubber powder and the like.

The extruded product is taken by the take-up device 13. The take-up speed by the take-up device 13 is taken at a speed higher than the extrusion speed. In the present invention, when the bubbles are taken at a speed higher than the extrusion speed, cracks are partially formed between the independently foamed cells, and when the cracks are continuous, the rubber powder is sewn into continuous bubbles to form a passage. This passage allows liquid and gas to pass through. Therefore, the transmittance (aperture ratio) can be adjusted by the take-up speed.
That is, when the extrusion speed and the take-up speed are the same, the transmittance becomes zero, and as the take-up speed becomes faster, the amount of cracks increases and the transmittance becomes larger.

The extrusion speed varies depending on the extruder and the shape of the product, but in general, the extrusion speed is 1.1 to 1.7 m / min, and the take-up speed is 1.2 to 2.0.
Therefore, the take-up speed is preferably 3 to 30% higher than the extrusion speed.

In this way, after extrusion molding, the passages are formed by communicating the bubbles by taking them out at a speed higher than the extrusion speed, but between the extruder 10 and the take-up device 13 in order to facilitate winding. A cooling device 11 is arranged. Cooling system
Reference numeral 11 is a means for causing the foamed layer to be cracked by the take-up device 13 to solidify the molded article having permeability, and the cooling means may be air, cold water, or the like.

When cooled immediately after extrusion, it is impossible to cause cracks in the foam layer of the product, so it is necessary to maintain a sufficient distance between the extruder 10 and the cooling device 11 is 0.5 m or more, preferably 1 m. Install them apart from each other.

Further, by combining the cooling device 11 and the take-up device 13, it is possible to manufacture a product having a transparent portion and a non-permeable portion.

For example, by synchronizing or speeding up the take-up device 13 with the extruder 10, or by placing the cooling device 11 immediately in front of the extruder 10 and repeating turning on and off, the product is permeable and non-permeable. The parts can be formed alternately. Such a product is effective when watering only a plant such as vegetables efficiently. Further, when only the lower portion of the product in the axial direction is cooled, the permeable portion and the non-permeable portion can be formed in the vertical direction of the cross section. Such a product is effective when used as a mounting method or a buried method. Further, by gradually increasing or decreasing the take-up speed by the take-up device 13 instead of being constant, products having different transmittances at both ends can be obtained. Thus, if the transmittance is increased as it goes to the tip, the amount of water sprayed does not change even at the tip, and uniform water spray can be obtained.

Finally, the product taken up by the take-up device 13 is the take-up device.
Take up by 15.

The cooling device 11 can be omitted by changing the winding device 15.

FIG. 2 is a partially enlarged cross-sectional view of the hose manufactured by the above method.

1 is a vulcanized rubber powder, 3 is a resin foam layer, 5 is air bubbles, 7
Is a crack. The vulcanized rubber powder 1 is wrapped in the resin foam layer 3 and firmly adhered by the olefin resin. The crack 7 communicates with the bubble 5,
Therefore, the closed bubbles are formed as continuous bubbles, and liquid and gas can be transmitted from one side surface to the other side surface.

(Effect of the Invention) This invention utilizes the incompatibility that the vulcanized rubber does not melt with the resin. By mixing the rubber powder, the vulcanized rubber retains a predetermined shape and a constant speed even though it is a foam. be able to.

More specifically, a foamed molded product made of a resin can be obtained as a molded product capable of passing through continuous cells by increasing the amount of foaming, but such a molded product does not have self-shape retention. Therefore, in the present invention, rubber is not simply used as an extender,
It was used to have strength and to adjust the transmittance. Then, the foam layer can communicate with each other by a tensile force between the rubber powders to form the closed cells into the continuous cells. However, since the rubber and the resin are bonded by the olefin resin powder, the molded article as a whole is It has a certain strength.

(Example) Below, the Example of this invention is shown.

60 parts by weight of 50 mesh rubber powder obtained by crushing a tire that is a vulcanized product of SBR and natural rubber, and 30 mesh of vinyl-based resin powder made by Nippon Unicar Co., Ltd. PES-400
20 parts by weight and 20 parts by weight of NR-106 manufactured by Mitsui Petrochemical Industry Co., Ltd., which is 30 mesh as an olefin resin powder, and 20 parts by weight as a foaming agent, Exceller QN manufactured by Eiwa Chemical Industry Co., Ltd.
0.3 parts by weight of o.25 was mixed using a tumbler while adding 0.2% of mineral oil as a wetting agent.

A hose having an inner diameter of 13 mm and an outer diameter of 18 mm was extruded from the compounded material by an extruder at an extrusion speed of 1.5 m / min and a take-up speed of 1.8 m / min. Cooling is about 1.5m away from the extruder
This was done by passing through a 20 degree water bath.

This hose was lightweight, had self-shape retention, and was able to obtain a kink-free hose.

When this was used as a watering hose, changes in the water discharge amount were tested in relation to the measurement position and the water pressure.

The test method is to connect one end of a sprinkler hose with a total length of 7 meters to the tap of the water supply, attach a pressure gauge to the other end, place a saucer A at a position 3 meters from the evil mouth, and then receive saucer B every 0.8 m. , Saucer C, saucer D, and saucer E were placed. In this state, the stopper was fully opened and the amount of water accumulated in the pan was measured for 1 minute.

In the above test, changes in water pressure and water discharge were also tested.
That is, the change in the amount of water at each measurement position when the water pressure was changed in the above test method was measured.

FIG. 3 shows the relationship between the measurement position and water pressure and the water discharge amount.

In the above test results, there are some differences depending on the measurement position,
This difference does not pose a problem in practical use. From this test result, it was found that there was almost no difference in the water spray amount depending on the position in the length direction. On the other hand, it is known that the conventional product in which small holes are formed in the peripheral wall of the hose has a decrease in water pressure in proportion to the flow rate and the amount of water sprinkled gradually decreases, which is a marked difference from the above-mentioned embodiment.

Further, when the water pressure is changed, the water discharge amount increases according to the water pressure, and the water spray amount can be adjusted by the water pressure.

(Effects of the Invention) As described in detail above, according to the present invention, it is possible to obtain a lightweight and flexible rubber-molded product that can permeate liquids and gases in one step without requiring post-processing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side view for explaining the manufacturing process of the present invention.
FIG. 2 is a partially enlarged cross-sectional view of the molded product, and FIG. 3 is a graph showing the test results of the water spray amount in relation to the measurement position and water pressure. 1 is a vulcanized rubber powder, 3 is a resin foam layer, 5 is air bubbles, 7
Is a crack, 10 is an extruder, 11 is a cooling device, 13 is a take-off device, 15
Take-up device

 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-58-167628 (JP, A) JP-A-62-11739 (JP, A) JP-A-58-81133 (JP, A)

Claims (1)

[Claims] 1. 40-80 parts by weight of rubber powder of 20-80 mesh finely divided by mechanical treatment, 10-30 parts by weight of vinyl resin powder of 20-80 mesh, and olefin resin of 20-80 mesh. 10 to 30 parts by weight of powder and 0.1 to 1 part by weight of a foaming agent powder are mixed to prepare a mixed powder material, and the mixed powder material is foam-molded by an extrusion molding method,
A method for producing a rubber molded article which is permeable to liquid and gas, characterized in that, after the foaming molding, before the product is solidified, bubbles are communicated between the rubber powders by taking it off at a speed higher than the extrusion molding speed.