JPH1080901A - Powder rubber and absorbent for oil or solvent using powder rubber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize hollow powder rubber, and thereby improve the performance of absorbing oils or solvents and enable the use of the powder rubber as an absorbent for the solvent or the oil by vulcanizing rubber, forming plural hollow parts in the surface of the powder and giving it a specific particle size and bulk specific gravity. SOLUTION: A lump of rubber as a raw material is charged into a kneader to start the kneading process. If the temperature of the rubber is increased to a specified level or higher, a vulcanizer and a vulcanization accelerator are added to the rubber and the mixture continues to be kneaded. The lump of rubber and the vulcanizer are converted to powder by the concurrent action to fluidize and knead them. In addition, during the vulcanization, numerous bubbles are formed by trapping air in the rubber and emerge on the surface when the rubber is pulverized resulting in the formation of an uneven part and a hollow part on the surface of the powder rubber. The particle size of this powder rubber is about 200-700μm and the bulk specific gravity is about 0.15-0.3g/cm<3> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder rubber having a large number of hollow portions (hereinafter sometimes referred to as "hollow powder rubber") and an oil or solvent adsorbent using the same.

[0002]

2. Description of the Related Art Methods for effectively using finite earth resources have been adopted in various fields. In the field of rubber, reuse of used rubber products and waste such as burrs generated in the process of manufacturing rubber products is being promoted. There are several ways to recycle, but recycling is one of them.

[0003] In order to be recycled and used as a raw material for a new product, it is required to pulverize the rubber, and the finely powdered rubber is mixed with the raw rubber to produce a product. In order to integrate the powder rubber with the product, it is necessary to pulverize as much as possible, but since the rubber product has been vulcanized, pulverization involves difficulty.

The present inventors have been studying how to finely pulverize vulcanized rubber with a dry sand mill. In addition, the present inventors have conducted experiments on how carbon black and various additives are mixed in a horizontal twin-screw kneader. In this experiment, butadiene rubber, which is a raw rubber, and a tracer are mixed and kneaded in a kneader, and the number and distribution of tracers appearing on a cut surface are clarified by cutting a lump of rubber every kneading time. It is done by doing.

However, in the case of unvulcanized rubber, the strength is low, and the rubber sticking to the kneader is torn off when the rubber is taken out of the kneader, and the kneading state cannot be clarified. Focusing on whether vulcanization would improve the strength of the rubber and remove it in a lump, and tried vulcanization while kneading it, the rubber turned into powder instead of lump.

[0006] Observation of the rubber powder shows that it has a soft property in a plump form just like a mushroom. When this was observed with an electron microscope, many irregular irregularities formed on the surface of the rubber powder and many irregular hollow portions formed by the irregularities were found.

When this powder rubber was sprayed on the surface of machine oil dropped on water in an attempt, it spread quickly on the surface of the oil, absorbed the oil, and settled while floating on the water with the oil absorbed. Did not. Also, when a mixture of the powder rubber and the powder rubber that has been powdered after vulcanization is sprayed on the surface of the machine oil in the same manner, the oil spreads quickly on the oil surface, absorbs the oil, and in a state where the oil is absorbed. It did not settle while floating on the water surface. The present invention has been completed based on these findings.

[0008]

Accordingly, an object of the present invention is to provide a hollow powder rubber and a powder rubber. Another object of the present invention is to provide an adsorbent for oils and solvents using the hollow powder rubber as a main raw material.

[0009]

The constitution of the invention adopted to achieve the above object is as follows. In the first aspect, the present invention is a vulcanized powder rubber, which has a large number of hollow portions on its surface, a particle size of 200 to 700 μm,
It is a powder rubber characterized by having a bulk specific gravity of less than 0.15 to 0.3 g / cm ³ .

A second aspect of the present invention is the powdered rubber according to the first aspect, characterized in that it has a soft property in a plump form like a mushroom.

According to a third invention, there is provided a vulcanized powder rubber, wherein the powder rubber contains the powder rubber according to the first or second invention. It is rubber.

In a fourth aspect, the first, second or third aspect is provided.
An oil or solvent adsorbent characterized by using the powdered rubber according to the invention as a main raw material.

The rubber used in the present invention includes various rubbers, and typical examples thereof include butadiene rubber (BR) and nitrile butadiene rubber (NBR), but are not particularly limited thereto. is not. The particle size of the hollow powder rubber is about 200 to 700 μm. The bulk specific gravity is generally 0.15 to 0.3 g / cm ³ .

[0014] The hollow powder rubber has good absorbability for solvents and oils,
The solvent absorbs about 10 times the weight, and the oil absorbs about 3 times the weight. Even if the particle size is large, it seems to absorb about twice the weight. Further, since it has a bulk specific gravity smaller than 1.0 and floats on water, it is suitable as an oil absorbing material for oil leak accidents in rivers or the sea. It should be noted that the same function as described above can be obtained even when the vulcanized rubber is mixed with a powder rubber obtained by pulverization.

In the present invention, an apparatus for kneading rubber and a vulcanizing agent is used. This apparatus is usually called a kneader, but a disperser or a pulverizer can also be used. That is, it is sufficient that the rubber and the vulcanizing agent can be kneaded regardless of the name, and examples thereof include a kneader, a Banbury, a ball mill, and a vibrating ball mill. Among them, two mixing chambers are provided side by side, these mixing spaces are connected, and rotor blades are respectively arranged in the mixing spaces, and the rotors are rotated in parallel and opposite directions to transfer contents in the mixing chamber. The horizontal twin-screw kneader thus configured seems to have high production efficiency.

In manufacturing, a mass of rubber as a raw material is put into a kneading machine and kneading is started. In this case, it seems that the filling rate in the kneading chamber is preferably about 70 to 80%. If it is too large, the formation of irregularities and hollow portions is not good. When the temperature of the rubber rises to some extent, a vulcanizing agent and a vulcanization accelerator are added and kneading is continued. When a large amount of the vulcanization accelerator is mixed, the vulcanization rate is increased, and when it is small, the vulcanization rate is decreased. The vulcanization rate can be changed by changing the type of vulcanization accelerator or the combination thereof. Therefore, the vulcanization speed can be controlled by the vulcanization accelerator.

The rubber mass and the mixed vulcanizing agent and the like are kneaded while flowing, and are converted into powder. The pulverization starts in the middle of the kneading and continues as it is to obtain a hollow powder rubber. Although the mechanism of the formation process of the irregularities and the hollow portions is not clear, a large number of bubbles are formed by enclosing air in the rubber during vulcanization, and these bubbles appear on the surface during powderization. As a result, it is as if the unevenness and the hollow portion are formed on the surface of the rubber powder.

For comparison, two types of vulcanized rubber were pulverized by using the same kneader or pulverizer. One is burrs of the product, which contains carbon black and the like. It is a powdered vulcanized rubber obtained immediately after vulcanization or by re-kneading a vulcanized rubber mass taken out of the same apparatus. The former vulcanized rubber containing carbon black and the like was merely a rubber powder, and no irregularities and hollows were formed on the surface of the rubber powder. Some irregularities and hollow portions were formed.

The powder rubber powdered after vulcanization has good fluidity. However, the hollow powdered rubber according to the present invention has a mousse-like form, and its flowability is not so good. For this reason, fluidity can be adjusted by appropriately blending the powdered rubber that has been powdered after the above vulcanization according to the purpose of use or application.

When vulcanization is carried out while kneading the rubber, the vulcanization is carried out by the heat generated by the rubber itself due to kneading, so that an external heat source normally required for vulcanization is not required. In addition, since the vulcanization reaction occurs while kneading, finer powdering proceeds and the particle size distribution becomes sharper.

[0021]

EXAMPLES The present invention will be described in more detail with reference to Examples. Example 1 Hollow powder rubber was produced using a horizontal twin-screw kneader as a kneader. This kneader has two mixing chambers,
These mixing spaces are connected, and rotor blades are respectively arranged in the mixing spaces, and the contents are delivered and received in the mixing chamber by rotating the rotors in parallel and in opposite directions.

With respect to the volume of the mixing chamber with the rotor attached, the filling rate is 70 vol. % BR rubber at a rotor speed of 30 r. p. m. When the rubber temperature reached 70 ° C., the medicines shown in Table 1 were introduced in order from the top at intervals of 2 to 3 minutes. When the rubber temperature reaches 100 ° C, the vulcanization accelerator N
After the introduction of S, the fluid was changed from the fluid to the powder at about 3 to 5 minutes after the introduction, and a hollow powder rubber was obtained 10 minutes after the introduction.

[0023]

[Table 1]

The obtained hollow powder rubber has a particle size distribution of 21%.
30 to 300% by weight, 300 to 500μ
m is 40% by weight and 500 to 710 μm is 2% by weight.
It was 0% by weight. When the solvent and oil were absorbed by the hollow powder rubber, the solvent absorbed about 10 times by weight and the oil absorbed about 3 times the weight. In addition, the bulk specific gravity of the hollow powder rubber was measured. The measurement was performed by placing hollow powder rubber in a measuring cylinder and measuring the amount and weight of the rubber several times. The result of each measurement is 0.15 to 0.30 g / cm
^{It was in} the range of ³ .

Example 2 Hollow powder rubber was produced by kneading, vulcanizing and pulverizing with a dry sand mill. Two types of large and small stainless steel beads (13 mmφ, 1.6 mmφ) were put in a sand mill as grinding media, and rubber was kneaded, vulcanized, pulverized and pulverized. Specifically, small beads and rubber were mixed into the gaps of the large beads in a volume of 1/2 each. In this example, 400 cc of large beads were used.

As a raw rubber, BR is cut into about 0.5 cm square, 3% of ZnO, 1% of stearic acid, 1% of vulcanizing agent, 1% of vulcanizing agent M, N
S was simultaneously added at 1% and 0.45%, respectively. After raising the wall temperature of the sand mill to 100 ° C.,
p. m. For 35 minutes. In this case, the vulcanized and pulverized hollow powder rubber agglomerates and has a size of 300 to 10
It became 00 μm.

When the bulk specific gravity of the hollow powder rubber was measured in the same manner as in Example 1, the result of each measurement was 0.15 to 0.15.
It was within the range of 0.30 g / cm ³ . The difference from Example 1 is considered to be due to the difference in the kneader. When the solvent and oil were absorbed by the obtained hollow powder rubber, the solvent absorbed about 10 times by weight and the oil absorbed about 3 times the weight.

Example 3 Hollow powder rubber was produced by kneading and vulcanizing rubber in a two-roll mill. After setting the roll surface temperature to 110 ° C. with a heater, the roll interval was set to 3 mm, and BR rubber was put therein and mixed for about 10 minutes. In this case, the roll rotation speed is 19r.
p. m. And 23r. p. m. It is. Next, the same chemicals as in the closed-type twin-screw kneader of Example 1 were mixed at a similar ratio every about 3 minutes.

After about 1 hour and 30 minutes from the start of kneading, when the roll surface temperature reached 160 ° C. and the rubber surface temperature reached 110 ° C., vulcanization and pulverization of rubber began to be observed. At this time, the roll gap was set to 1.8 mm. The hollow powdered rubber obtained at this time was a collection of secondary aggregates having a particle size of about 500 μm, and kneading was continued for 30 minutes thereafter to obtain a chain of hollow powdered rubber aggregates.

The reason that the hollow powder rubber did not disperse and became a chain of aggregates is that the kneading section of the apparatus is in an open state during kneading, vulcanization and pulverization using a roll mill, so that the roll and rubber are not dispersed. It is supposed that the temperature rise is remarkably small, and that heat is released from the rubber when it comes out of the roll gap. Therefore, it is difficult to obtain the temperature most required for vulcanization, and a long operation time is required.

When the bulk specific gravity of the hollow rubber powder was measured in the same manner as in Example 1, the result of each measurement was 0.30 to 0.30.
It fell within the range of 0.40 g / cm ³ . The difference from Example 1 is considered to be due to the difference in the kneader. When the solvent and oil were absorbed by the obtained hollow powder rubber, the solvent absorbed about 7 to 8 times by weight, and the oil absorbed about 2.5 times the weight.

Example 4 In order to pulverize the burrs of ethylene propylene rubber (EP) discharged in the factory, 50% of EP and 50% of unvulcanized BR are mixed into the kneader of Example 1. Rubber temperature is 1
When the temperature reached 00 ° C., the drugs shown in the following table were sequentially charged at intervals of 2 minutes. Then, kneading was performed for 60 minutes after the addition of the vulcanization accelerator CZ.

[0033]

[Table 2]

The bulk density of the resulting mixed hollow powder rubber is:
It was about 0.3 to 0.5 g / cm ³ . The absorption of the solvent is 5 to 6 times by weight, and about 2 times in the case of oil. In the case of BR (50%) EP (50%), the particle size distribution is 213 to 300 μm, 19% by weight, 300 to 300%.
47.5% by weight of 500 μm, 500-710 μm
m is 18% by weight. As the properties, the fluidity of the powder is good. It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the claims.

[0035]

According to the present invention, hollow powder rubber can be provided because of the above constitution. Further, the powder rubber has a hollow portion, so that it has a good solvent or oil absorption performance and can be used as a solvent or oil absorber. In particular, since the bulk specific gravity is light, and after absorption, it agglomerates into a ball and floats on water, so it is suitable for oil leakage from the sea or river. Other materials that use foam properties, such as insulation materials and sound absorbing materials, fenders, non-slip materials for floors and roads, cushioning materials, building materials such as walls and floors, filler materials for reducing the weight of shoes and tires, roads And rubber and plastic fillers, oil fence materials, non-slip and cushioning materials such as furniture and stairs handrails, bathtub materials, compressor mist catchers, adsorbents for waste oil discharged from home kitchens, and gas adsorbents Can be used as

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29K 105: 04 105: 24

Claims (4)

[Claims] 1. A vulcanized powder rubber, which has a large number of hollow portions on its surface, a particle size of 200 to 700 μm, and a bulk specific gravity of 0.15 to 0.3 g / c
powder rubber characterized by having a particle size of less than m ³ . 2. The powdery rubber according to claim 1, wherein the powdery rubber has a soft property in a muffled, plump form. 3. Vulcanized powder rubber, wherein the powder rubber contains the powder rubber according to claim 1 or 2. 4. An adsorbent for oil or a solvent, comprising the powdered rubber according to claim 1, 2 or 3 as a main raw material.