JP2526167B2 - Method for processing detergent composition for rubber processing machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a composition of a cleaning agent used for color change or material change of a rubber processing machine.

More specifically, it relates to a detergent composition containing an ethylene-propylene copolymer, calcium carbonate or basic magnesium carbonate, and sodium alkylsulfonate or sodium alkylbenzenesulfonate and a method for using the same.

(Prior Art) In recent years, in synthetic rubber processing, high-mix low-volume production is frequently performed, and a large amount of replacement material loss and time loss due to switching work are involved in color change or material change.

In particular, when switching from a dark color grade such as black to a natural grade, it is difficult to remove stains of the preceding grade adhering to the cylinder or nozzle, and it is necessary to remove a large amount of natural grade for a long time.

In addition, there is a compound in which an inorganic compound and a surfactant are mixed with a base polymer such as polyethylene, polypropylene and polystyrene as a cleaning resin composition for a plastic molding machine, but these cannot exert a cleaning effect at a temperature below the melting point of the base polymer. .

(Problems to be Solved by the Present Invention) With conventional cleaning agents for plastic molding machines, it is difficult to wash because they are hard to penetrate into the synthetic rubber processing machine.

(Means for Solving Problems) The present inventors have made silicone rubber, EPDM (Ethylen-propyle)
ne-diene-methylene rubber (ethylene-propylene copolymer) etc. was intensively studied on a cleaning composition that can be used for color change and resin change of a synthetic rubber processing machine that is processed at 120 ° C or lower, and a specific ethylene-propylene copolymer, Use of a granular or plate-like composition of calcium carbonate or basic magnesium carbonate and sodium alkyl sulfonate or sodium alkyl benzene sulfonate as a purge compound significantly reduces subsequent replacement material and shortens cleaning time I examined if I could do it.

 The present invention has the following configurations.

Intrinsic viscosity [η] 0.5 to 20 with ethylene content of 20 to 50% by weight
Cleaning of a rubber processing machine containing 35 to 60% by weight of ethylene-propylene copolymer of 2.5, 35 to 60% by weight of calcium carbonate or basic magnesium carbonate, and 1 to 5% by weight of sodium alkylsulfonate or sodium alkylbenzenesulfonate. A method for processing a detergent composition for a rubber processing machine, wherein the agent composition is used at a processing temperature of 120 ° C or lower.

In the present invention, the ethylene-propylene copolymer may be an ethylene-propylene block copolymer production product, and a by-product which is a hexane-soluble product generated during production may be used, and the ethylene content is 20% by weight. If it is less than less than 50% by weight, tackiness is lost, and if it exceeds 50% by weight, it becomes too hard and remains. If the intrinsic viscosity [η] is less than 0.5, it will be too soft, resulting in poor cleaning. If it exceeds 2.5, it becomes too hard, resulting in poor cleaning. This [η] is a value measured at 135 ° C. with solvent tetralin, and the ethylene-propylene copolymer is easily available as a commercial product.

The composition of the present invention contains 35 to 60% by weight of calcium carbonate or basic magnesium carbonate. If the amount of calcium carbonate or basic magnesium carbonate is too much, the detergency is lost, and conversely, if the amount of causium carbonate or basic magnesium carbonate is too small, the removability of contaminants from the rubber processing machine is poor, and the cleaning effect becomes insufficient.

The composition of the present invention contains 1 to 5 sodium alkyl sulfonate or sodium alkyl benzene sulfonate.
It is mixed by weight. If the amount of sodium alkyl sulfonate or sodium alkyl benzene sulfonate is too much, it becomes slippery, resulting in poor cleaning, and at least the cleaning effect is insufficient.

Exemplifying the method for producing the composition of the present invention, ethylene-propylene copolymer, calcium carbonate or basic magnesium carbonate and sodium alkyl sulfonate or sodium alkylbenzene sulfonate are charged in a pressure kneader and kneaded to give a bulk compound. It is obtained by taking out, rolling with two rolls and forming into a plate shape. The composition of the present invention can be used in the form of the plate obtained as the plate or in the form of pellets cut into a square shape with a sheet cutter.

The composition of the present invention can be used as a cleaning agent for rubber processing machines such as Banbury, pressure kneader, extruder, injection molding machine and compression molding machine.

Next, the cleaning test evaluation method of the present invention will be described below with reference to examples.

1 kg of black silicon rubber containing 2% by weight of carbon black is weighed into an extruder having a diameter of 40 mm and the whole amount is extruded at a temperature of 60 ° C. and a rotation speed of 30 rpm. Charge 100 grams of cleaning composition and extrude under the same conditions.

Finally, add the replacement natural color silicone rubber and let it flow until the color disappears to obtain the consumption of the replacement natural color silicone rubber. In addition, the time from the addition of the cleaning composition to the disappearance of the color is measured as the cleaning time.

Example 1 An ethylene propylene copolymer 1.8 having an ethylene content of 33% [η] 1.2 was added to a test pressure kneader having an internal volume of 3 liters.
5 kg, calcium carbonate 2.05 kg, and sodium alkylsulfonate 0.10 kg were charged and kneaded for 6 minutes while pressurizing to 2 to 5 kg / cm ² , and then opened to take out a lump composition.

The lump composition was charged into a 10-inch roll having a surface temperature of 33 ° C. and rolled into a sheet having a thickness of 5 mm to draw out the plate composition. The durometer hardness HDA of this product according to JIS-K7215-86 was 55.

100 g of pellets obtained by cutting the composition was charged in an extruder having a diameter of 40 mm contaminated with black silicon and extruded at a temperature of 60 ° C. and a rotation speed of 30 rpm, and then replaced with a natural color silicone rubber until the black color disappeared. did. The consumption of the natural-color silicone rubber required for the replacement was 500 g. The washing time was 5 minutes.

Example 2 Ethylene propylene copolymer 2.3 having an ethylene content of 48% [η] 2.1 was added to a test pressure kneader having an internal volume of 3 liters.
2 kg, basic magnesium carbonate 1.50 kg, and sodium alkylbenzene sulfonate 0.18 kg were charged and kneaded for 5 minutes while pressurizing and then opened to take out a lump composition.

The lump composition was charged into a 10-inch roll having a surface temperature of 33 ° C., rolled into a sheet having a thickness of 5 mm, and drawn out as a plate composition. The durometer hardness HDA of this product according to JIS-K7215-86 was 61.

A washing test was conducted under the same conditions as in Example 1, using 100 grams of pellets obtained by cutting the composition. The consumption of the natural-colored silicone rubber required for the replacement was 800 g. The washing time was 6 minutes.

Comparative Example 1 The same black silicone rubber as in Example 1 was contaminated 40
A mm-sized extruder was charged with a natural color silicone rubber and replaced until the black color disappeared. The consumption of the natural-color silicone rubber required for the replacement was 7.5 kg. The washing time was 30 minutes.

Comparative Example 2 The same black silicone rubber as in Example 1 was contaminated 40
In an extruder having a diameter of mm, 50% by weight of an ethylene-propylene copolymer having an ethylene content of 5% by weight and an intrinsic viscosity [η] 2 of
A cleaning agent composition for plastic processing machines (Rockwell hardness HRR101 according to JIS-K7202-82) containing 46% by weight of calcium carbonate and 4% by weight of sodium alkylbenzene sulfonate was added, but it was hard to melt and inside the molding machine. Is not sent to. Therefore, washing was impossible.

(Effects of the Invention) With the conventional cleaning agent for plastic molding machine, it was impossible to wash the synthetic rubber processing machine used at a relatively low temperature because of its high hardness, and it could not be washed. Silicone rubber, which has traditionally been difficult to clean,
We were able to significantly improve the cleaning of synthetic rubber processing machines such as EPDM. By using the composition of the present invention, the amount of the subsequent replacement rubber consumed can be reduced to the conventional 6 to 12% and the cleaning time to about 20%.

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Claims (1)

(57) [Claims] 1. An ethylene-propylene copolymer 35-60 having an ethylene content of 20-50% by weight and an intrinsic viscosity [η] of 0.5-2.5.
% By weight, calcium carbonate or basic magnesium carbonate
A cleaning composition for a rubber processing machine containing 35 to 60% by weight of sodium alkylsulfonate or 1 to 5% by weight of sodium alkylbenzenesulfonate was added at a processing temperature of 12%.
A method for processing a cleaning composition for a rubber processing machine, which is used at 0 ° C or lower.