JPH0737545B2 - Rubber molded product manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to agricultural irrigation, sprinkling, fertilizing hoses, and aeration diffusers for general upland fields (house cultivation, open field cultivation), orchards, horticulture and the like. Alternatively, the present invention relates to a method for producing a rubber molded product which requires permeation of liquids and gases such as filters and flower pots.

(Prior Art) Conventionally, an irrigation sprinkler hose for planting in agricultural, horticultural, and greening facilities is formed by forming a large number of small holes in the peripheral wall of the hose, and exuding or watering from the small holes.

That is, after forming a predetermined hose by a known manufacturing method, a small hole is formed as a post-process in the peripheral wall of the hose.

Further, these hoses include soft hoses and hard hoses depending on their materials. There are also methods of using the hose, such as an overhead method that is used by hanging it overhead, a mounting method that is used while it is placed on the ground, and an embedding method that is used by being buried underground. Is used as an overhead method, and in greenhouse cultivation and open field cultivation, it is used as a mounting method or a buried method.

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

That is, in the case of a soft hose, since the hose can be wound up while being crushed, it has advantages that it does not take up much space for storage and is convenient to carry. However, the soft hose cannot maintain its own shape, causing kinks such as twisting and kinking, and not only clogging when the residual liquid dries while being crushed, but also liquid passing due to the adhesive action of the residual liquid. However, there is a problem that it doesn't spread even if it is crushed.

Moreover, the flow rate is not constant when kinking with a soft hose.

On the other hand, since the hard hose is not easily deformed, there is no risk of crushing or kinking, but there is a problem that 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 by a simple method and does not cause kink, and is permeable to other liquids and gases. It is an object of the present invention to provide a method for producing a rubber molded product.

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

That is, rubber powder 60-
90 parts by weight, 10 to 40 parts by weight of resin powder, 0.2 to 2 parts by weight of ionomer powder and 0.2 to 1 part by weight of foaming agent powder are mixed with the total amount of the above rubber powder and resin powder. A powder is created, this mixed powder material is molded by extrusion or injection molding, the resin encapsulating the rubber powder is foamed, and a rubber molded product in which bubbles separated by a thin film in this resin layer are made continuous It is characterized in that liquid and gas can be permeated by applying pressure.

FIG. 1 is a sectional view of a molded product manufactured according to the present invention, in which 1 is a vulcanized rubber, 2 is a resin, and 3 is a bubble. Rubber 1
Is surrounded by a resin 2, and the resin 2 has bubbles 3 as a foam. The rubber 1 and the resin 2 are bonded by an ionomer.

It has been known to blend a vulcanized rubber and a resin from the past, but the conventional blending of a vulcanized rubber gives elasticity.
Alternatively, it was intended as a bulking material. The rubber powder in the present invention is used for a completely different purpose from the conventional one, and utilizes the incompatibility between the vulcanized rubber and the resin.

That is, the vulcanized rubber does not melt with the resin, and 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 vulcanized rubber, even though it is a foam body in which cells partitioned by a thin film are continuous.

Further, in the present invention, the resin is not pellet but powder. This is because the dispersion of the powder is made uniform by using the powder.

The rubber powder used in this invention is crushed vulcanized rubber,
It is a granular or powdery rubber obtained by mechanical treatment such as cutting or polishing, and may be natural rubber, synthetic rubber or a blend thereof. The size of the powder depends on the intended molded product, but it should be 10 to 50 mesh. The amount of rubber powder mixed is 60 to 90 parts by weight. The mesh can be increased to increase the amount of liquid passing or aeration, and conversely, the mesh can be decreased to decrease the amount of liquid passing or aeration.

Further, the resin powder may be any of thermoplastic resins such as PP, PE and nylon, and a hard resin is used when increasing the pressure resistance, and a soft resin is used when decreasing the pressure resistance.
The size of the powder is 10 to 50 mesh, and mixed at a ratio of 10 to 40 parts by weight. Usually, the resin is made into pellets for the convenience of handling, but in the present invention, it is used as a powder in order to improve the dispersion with the rubber powder.

Ionomer is used as a structural adhesive for rubber powder and resin powder, and further facilitates the kneading operation to have melt fluidity and imparts flexibility and strength to the molded product. The ionomer used here is 10 ~ based on the total amount of rubber powder and resin powder.
Mix 0.2 to 2 parts by weight of 50 mesh powder.

The foaming agent is, like the ionomer, 0.2 to 1 part by weight based on the total amount of the rubber powder and the resin powder.

The above blending materials are blended with a tumbler or a super mixer. At the time of blending, it is preferable to add a wetting agent such as mineral oil in an amount of 0.1 to 0.3% to improve dispersion.

After compounding in this way, it may be molded by extrusion or injection molding in the same manner as in ordinary foam molding of rubber.

In the molded article according to the present invention, the foam layer is continuous between the rubbers 1. When water pressure or air pressure is applied from one side, the first thin film breaks and reaches the next bubble, and the next thin film breaks. In this way, the thin films are ruptured one after another, and the bubbles continue, and finally penetrate to the other side. When the thin film between the bubbles is broken by the pressure, a passage is formed in the foamed layer so as to sew between the rubbers, so that liquid passage and ventilation can be performed.

As described above, since the molded article according to the present invention is liquid-permeable and breathable, when the hose is manufactured by the foam molding method by extrusion, these hoses are used for irrigation, sprinkling, water absorption, or fertilization as a fertilizing hose. It can be used for gardening. Furthermore, these hoses can be used as an aeration diffuser in fish culture, or as a filter. Since the hose produced by the present invention is mixed with vulcanized rubber powder, it has not only some strength but also flexibility, self-shape retention, and no kink. Further, since it has a foam layer, it is lightweight.

Therefore, the hose manufactured according to the present invention can be used in any of the overhead system, the mounting system and the burying system, and the handling is simple and the cost is low.

Moreover, although various shapes of molded products can be obtained by the injection molding method, the range of use thereof such as flower pots, filters, and condensation prevention plates is wide. Since it is injection molding, not only the shape is free and inexpensive, but also a product excellent in pressure resistance, heat resistance and flexibility can be obtained.

(Operation of the Invention) The present invention utilizes the incompatibility that the vulcanized rubber does not melt with the resin. Since the mixed resin holds the rubber in a state in which it is wrapped, the rubber is wrapped in the foam layer by foaming this resin layer. The foam layer is formed by connecting air bubbles separated by a thin film and is mixed with rubber. Therefore, the foam layer can maintain a predetermined shape and a constant strength even though it is a foam.

More specifically, even if the resin is foamed, a molded product that can pass through can be obtained by increasing the foaming amount, but such a molded product does not have self-shape retention. Therefore, in the present invention, not only the rubber is used as a bulking material, but also the strength is imparted and the thin film forming the bubbles is acted as a wall for blocking the pressure when the thin films are ruptured one after another at a constant pressure to communicate with each other. It is used to In the case of a simple foam, when pressure is applied from one side, the bubbles are compressed and the pressure is dispersed, but the thin film cannot be broken, but if the pressure is increased more than necessary, the molded product itself will burst.

However, when the rubber powder is mixed, the pressure is concentrated between the rubbers, so that the pressure is not dispersed and the thin film can be broken one after another. When pressure is applied to the continuous bubbles, the relatively thin film breaks in the adjacent parts to communicate,
In the next part, the adjacent relatively thin film is torn, and in this way, the films are connected one after another and finally penetrate to the other side. The foam layer communicates with each other by pressure, but the rubber and the resin are bonded by the ionomer, and the molded product as a whole has a certain strength.

The molded article according to the present invention can be used as a molded article that allows liquid passage and ventilation by allowing the foam layer portion to communicate with each other at a somewhat high pressure.

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

80 parts by weight of 30-mesh rubber powder obtained by crushing tires, which are vulcanized products of SBR and natural rubber, and 20 parts by weight of 30-mesh PP powder, and 30-mesh ionomer (trade names: Himilan, Mitsui, DuPont Poly) Chemical Co., Ltd.
1.5 parts by weight and 0.5 parts by weight of a foaming agent were mixed using a tumbler while adding 0.2% of mineral oil as a wetting agent. This compounded material is extruded with an internal diameter of 10 mm × an external diameter of 25 mm
Was extruded at a speed of 25 m for 1 minute.

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

When this was used as a sprinkler hose, changes in the amount of water at each position in the length direction were tested.

As shown in FIG. 2, the test method is as follows. One end of the sprinkler hose H having a total length of 7 meters is connected to the tap 10 of the water supply, the pressure gauge 11 is attached to the other end, and the saucer No. 1 is placed 3 meters from the tap 10. After that, they were placed in order every 0.8 meters up to saucer No5. In this state, the stopper was fully opened to measure the amount of water accumulated in the saucer in 1 minute. The water pressure is 0.45 to 0.48 kg / cm ² , the water temperature is normal temperature (24 ° C), and the pan is a container with a diameter of 550 mm.

The test results are as follows.

In the above test results, there is an average difference of 360cc between the saucer 4 and the saucer 5, but 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 water pressure of the conventional product in which small holes are formed in the peripheral wall of the hose decreases in proportion to the length thereof, and the amount of water sprinkled gradually decreases, which is a marked difference from the above-mentioned embodiment.

Next, the change in the amount of water sprayed due to the difference in water pressure was tested. As shown in FIG. 3, the test method was as follows. One end of a sprinkler hose having a total length of 1 meter was connected to a tap 10 and a pressure gauge 11 was attached to the other end to measure the amount of water accumulated in a saucer No. 6 in 1 minute. The water temperature is room temperature (24 ° C).

The test results are as follows.

The amount of water spray changes depending on the water pressure. Therefore, the amount of water spray 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 drawings]

FIG. 1 is a cross-sectional view of a rubber molded product according to the present invention, and FIGS. 2 and 3 are explanatory views showing a method for testing the water sprinkling amount of a hose. 1 is rubber, 2 is resin, 3 is air bubble

Claims (1)

[Claims] 1. 60 to 90 parts by weight of rubber powder finely divided by mechanical treatment, 10 to 40 parts by weight of resin powder, and 0.2 to 2 parts by weight of ionomer powder with respect to the total amount of the rubber powder and resin powder. , Foaming agent powder 0.2 to 1
A mixed powder material is prepared by mixing in a ratio of parts by weight, the mixed powder material is molded by an extrusion or injection molding method, and liquid and gas can be permeated by applying pressure. Production method.