JP2002241407A - Peptizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a peptizer which, when added in the process of masticating a natural rubber, facilitates a metering operation, and is free from deterioration of the working environment due to dust. SOLUTION: A material containing a component effective for peptization is formed into a pellet shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflocculant to be added when masticating natural rubber, and to a deflocculant capable of improving the efficiency of the refining process and improving the working environment. is there.

[0002]

2. Description of the Related Art Since natural rubber generally has a high viscosity, prior to mixing with a filler or the like, mastication is carried out to reduce the viscosity. It is common to add a peptizer for the purpose of shortening. A peptizer is a compounding agent having an action of chemically cutting rubber molecules to impart plasticity, and is also called a peptizing accelerator or a peptizer, an aromatic disulfide-based compound, an aromatic mercaptan-based compound and their Zinc salts are often used. These deflocculating agents are usually compounded in an amount of about 0.01 to 5 parts by weight per 100 parts by weight of the raw rubber. Has become a problem. In addition, there is also a problem that dispersion in rubber is not enough because the amount of the peptizing agent itself is small.
Mixing the active ingredients for mastication with clay, calcium carbonate and other inorganic fillers has also been practiced, but still is not sufficient.

[0003]

An object of the present invention is to provide a peptizing agent which can be easily weighed, added and mixed under such circumstances, and which does not deteriorate the working environment due to dust. It is intended for.

[0004]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that the object can be achieved by making the deflocculant into a pellet form. . The present invention has been completed based on such findings. That is, (1) active ingredients for mastication (A)
(2) The material containing the active ingredient (A) is composed of the active ingredient (A) and the other material (B). (3) the deflocculant according to (2), wherein the other material (B) comprises a rubber (c) and an inorganic filler (d); 4) The peptizer according to the above (3), wherein the rubber (c) is polyisoprene and the inorganic filler (d) is a clay; and (5) the peptizing active ingredient (A) is an aromatic disulfide compound. Alternatively, the present invention provides the peptizer according to the above (1), which is a zinc salt thereof.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the peptizer of the present invention, the active ingredient for peptization (A) is an ingredient effective for chemically cutting rubber molecules of the peptizer to give plasticity. Meaning, any of the conventionally known active ingredients of a peptizing agent can be used as the active ingredient (A), and aromatic disulfide-based compounds, aromatic mercaptan-based compounds and the like can be used. Preferable examples include zinc salts, organic peroxides, nitro compounds, nitroso compounds and the like. In particular, aromatic disulfide compounds such as 2,2'-dibenzamide diphenyl disulfide (the following chemical formula (I)) and 2-benzamidothiophenylzinc (the following chemical formula (II)) and zinc salts thereof are preferable.

[0006]

Embedded image

The compound represented by the formula (I) is
As a single agent (Noctizer SS: Ouchi Shinko Chemical) or as a mixture with an additive such as stearic acid (Noctizer SD: Ouchi Shinko Chemical, Pepter 3S: Kawaguchi Chemical)
The compound represented by the chemical formula (II) alone (Noctizer SZ: manufactured by Ouchi Shinko Chemical) is commercially available as a peptizer. The deflocculant of the present invention is obtained by molding the above-described material containing the active ingredient for deflocculation into pellets (hereinafter, sometimes referred to as pellet-type deflocculant).
It is. The material containing the active ingredient for shaping to be molded is
Such as commercially available, may be a mixture of the active ingredient alone or a mixture of additives, but further other ingredients,
In particular, a material obtained by mixing the rubber (c) and the inorganic filler (d) is preferable in terms of ease of pelletization and compatibility with the rubber when used.

Examples of the rubber (c) include polyisoprene rubber (IR) and styrene-butadiene rubber (S
BR), polybutadiene rubber (BR), natural rubber (N
R) and the like, and polyisoprene rubber is particularly preferable from the viewpoint of compatibility with natural rubber. on the other hand,
Examples of the inorganic filler (d) include clay, calcium carbonate, magnesium carbonate, aluminum carbonate, silica, and the like. Clay is particularly preferred from the viewpoint of workability of pellets.

There is no particular limitation on the content of the active ingredient in the pelletized peptizer of the present invention.
2 to 50% by weight, preferably 2 to 20% by weight is suitable. In particular, each content in the pelletized deflocculant containing the active ingredient (A), the rubber (c) and the inorganic filler (d) (active ingredient / rubber / inorganic filler)
Is 2 to 50% by weight / 18 to 80% by weight / 18 to 80% by weight, preferably 2 to 20% by weight / 20 to 60% by weight.
/ 20 to 60% by weight is suitable. When the content of the active ingredients in these pellets is less than 2% by weight, it is necessary to use a large amount in order to obtain a predetermined effect when used as a peptizer. , 5
If it exceeds 0% by weight, the dispersibility in other constituent materials will be poor, and not only will the dispersion of the viscosity increase, but also the cost will increase. If the rubber content is less than 18% by weight, the processability during pellet production will be poor, and if it exceeds 80% by weight, the stickiness of the pellets will be strong and blocking will occur. If the content of the inorganic filler is less than 18% by weight,
Pellets are soft and difficult to measure or block easily. When the content exceeds 80% by weight, the pellets become too hard.

The shape of the pellet is not particularly limited, and may be various shapes such as a columnar shape, a granular shape, and a plate shape. A cylindrical shape having a diameter of 1 to 10 mm and a length of 1 to 10 mm is suitable. In addition, the hardness of the pellets, there is also no particular restriction on the adhesiveness, when used in mastication of rubber as a peptizer, particularly in the method of molding into a pellet shape that can be determined according to the specifications of the mastication device There is no restriction, and an appropriate method according to the desired shape, hardness, adhesiveness, etc. can be adopted.However, in the case of molding into the above-described column shape, a method by kneading, extruding, and cutting is appropriate. . At the time of molding, a processing aid such as fatty acid soap may be added within a range that does not affect the performance as a peptizer.

The pellet-type peptizer of the present invention is used by being added in the mastication process of natural rubber, but is easy to measure and can be measured with high precision by an automatic measuring device. It does not invite the deterioration. Furthermore, it is excellent in dispersibility in natural rubber, has no variation in viscosity as compared with the case where it is added in powder form, and the plasticizing effect is rather improved. The addition amount and mastication conditions as the active ingredient for mastication can be set exactly the same as in the case of the conventional powdery addition.

[0012]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Example Noctizer SD (trade name, manufactured by Ouchi Shinko Chemical, 2, 2 ')
15 parts by weight of a mixture of dibenzamide diphenyl disulfide and stearic acid at a weight ratio of 40:60), polyisoprene rubber (manufactured by JSR Corporation, trade name: IR22)
00) 40 parts by weight, clay (manufactured by Shiraishi Calcium Co., Ltd.)
Product name: Hard clay top) 42 parts by weight and 3 parts by weight of a processing aid are kneaded in a kneader, extruded as a strand, cut, and cut into a pellet-shaped peptizer having a diameter of 4 mm and a height of 4 mm ( An active ingredient of a peptizer (6% by weight) was produced. 820 g of this pellet-shaped peptizer was added to 110 kg of natural rubber (RSS No. 4), and masticated at a ram pressure of 5 kg for 120 seconds. The drop temperature at this time was 125 ° C. This mastication operation was performed 10 times, and the Mooney viscosity: ML1 + 4 (130) of each sample obtained was measured. The results were as shown in Table 1.

Comparative Example Noctizer S in place of 820 g of pelletized peptizer
D15% by weight and 85% by weight of calcium carbonate, except that 820 g of a powdery mixture was used.
The results are shown in Table 1.

[0014]

[Table 1]

From the data shown in Table 1, it can be seen that the use of the pellet-type peptizer of the present invention does not cause a variation in viscosity as compared with the case of using the conventional powder-type peptizer. It can be seen that the plasticizing effect is rather improved.

According to the present invention, when the natural rubber is added in the mastication step, the weighing operation can be easily performed, the weighing can be performed with high accuracy, and the working environment does not deteriorate due to dust. A peptizer can be obtained. Moreover, it has excellent dispersibility in natural rubber, and compared to the case where it is added in powder form,
There is no variation in viscosity, and the plasticizing effect is rather improved.

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Claims (7)

[Claims] 1. A peptizing agent characterized in that a material containing the active ingredient (A) is formed into pellets. 2. The deflocculant according to claim 1, wherein the material containing the active ingredient (A) is a mixture of the active ingredient (A) and another material (B). 3. The peptizer according to claim 2, wherein the other material (B) contains a rubber (c) and an inorganic filler (d). 4. The peptizer according to claim 3, wherein the rubber (c) is polyisoprene and the inorganic filler (d) is clay. 5. The method according to claim 1, wherein the active ingredient (A) is an aromatic disulfide compound or a zinc salt thereof. 6. The content of the active ingredient (A) for reducing mushrooms is 2 to 6.
3. The deflocculant according to claim 1, which is 50% by weight. 7. The content of the active ingredient (A), the rubber (c) and the inorganic filler (d) is 2 to 50% by weight, 18 to 80% by weight and 18 to 80% by weight, respectively. 4. A peptizer according to claim 3.