JPH0624724B2 - Thermoplastic resin composition for cleaning melt-kneading device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Object of the Invention) The present invention relates to a cleaning resin composition used in a thermoplastic resin processing and molding machine.

In the plastic molding process, some measures are taken to eliminate the influence of the preceding product when switching the product. Especially in the processing of colored products, when changing the color from dark blue preceding grades such as blue and black to lighter grades such as white, the inside of the molding machine is washed with a washing resin, and the complicated processing such as disassembly and cleaning of the processing molding machine is performed. The reality is that work and production stoppages will be forced. For example, in the case of color change in extrusion granulation molding, it is necessary to stop the extruder, remove the screw, clean the inside of the screw and cylinder by a method such as brushing, and then install the screw again. Is. In the process of replacing the preceding product with the replacement resin without removing the screw, a large amount of resin is required for cleaning, and stains on the complicated structure inside the extruder cannot be removed. I have a problem. Cleaning compounds are used to solve these problems. The cleaning compound makes it easier to remove the residue in the extruder, and attempts to complete the grade change by using a small amount of the replacement resin. Cleaning compounds include those containing a lubricant such as stearic acid and those using acrylic resin with a high melting temperature, but the former have insufficient cleaning effect, and the latter have strong odor. In addition, there is a drawback in that it is difficult to reuse the replacement resin if it is mixed in the replacement resin. Further, since the latter has a high melt viscosity, the complexity of work such as having to use the cleaning compound after removing the die, the breaker plate, the metal net, etc. is still unsolved. In addition, cleaning compounds containing glass fibers and the like also have drawbacks such as the fact that the replacement resin cannot be reused, the screen of the molding machine, and the wear of the cylinder.

Further, it is also practiced to use a material obtained by blending a powdery sodium alkylbenzene sulfonate with a substitution resin for cleaning a molding machine. However, since sodium alkylbenzene sulfonate is hygroscopic, the compound blended with it is easily wet, so that it crosslinks in the molding machine hopper, and the absorbed water causes deterioration of the cleaning effect. There is a difficulty in handling.

As another example of the thermoplastic resin composition for cleaning the melt-kneading device, there is an example in which calcium carbonate or talc is blended in an amount slightly smaller than or equal to or more than the amount of the blended thermoplastic resin. It is said that the purpose of blending a large amount is to "prevent slippage" of the composition in the melt-kneading device.

However, the cleaning achieved by this cleaning composition seems to be almost as if the interior of the device is scraped off by the cleaning composition. Therefore, a large number of washings inevitably causes wear and wear in the apparatus. In addition, this type of cleaning requires a considerably large amount of power to move the cleaning composition in the apparatus, and is therefore unacceptable to the molding processing industry, where a large number of small-lot small-sized companies occupy the majority of the industry. In other words, it is inevitable to put a large amount of power into the work that does not directly produce the product when frequently changing the resin or changing the color.

As is clear from the above, the purpose of the present invention is to
It is an object of the present invention to provide a cleaning thermoplastic resin composition that can be used in combination with a small amount of a replacement resin to remove the resin of the preceding type remaining in the processing molding machine by a simple operation.

(Structure of the Invention) As a result of various investigations on the washing method of the processing molding machine, the inventors have found that a thermoplastic resin composition obtained by mixing a neutral salt of alkylbenzenesulfonic acid and a water-repellent compound into a thermoplastic resin and granulating the thermoplastic resin composition is used. The inventors have found that they are excellent for the above purposes and completed the present invention. That is, the present invention is characterized by containing (1) 60 to 90.5% by weight of a thermoplastic resin, 8 to 30% by weight of a neutral salt of alkylbenzenesulfonic acid, and 0.5 to 10% by weight of a water repellent compound. A thermoplastic resin composition for cleaning a melt-kneading device, which is described below. Preferred embodiments thereof are shown in the following items (2) to (4).

(2) The thermoplastic resin composition for washing a melt-kneading device according to the above item (1), wherein the neutral salt of alkylbenzenesulfonic acid is a sodium salt of alkylbenzenesulfonic acid having an alkyl group having 6 to 16 carbon atoms. .

(3) A thermoplastic resin composition for washing a melt-kneading device according to the above item (1) or (2), wherein the content of the neutral salt of alkylbenzenesulfonic acid is 9 to 20% by weight.

(4) In any one of the items (1) to (3), the water-repellent compound is selected from higher fatty acid metal salts or composite metal soaps thereof, wax, fluid paraffin, synthetic wax and silicone. At least one thermoplastic resin composition.

Examples of the thermoplastic resin used in the composition of the present invention include polyethylene, polypropylene, polybutene, polyolefins such as polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polystyrene, polyacrylonitrile, or a combination thereof. Polymer resin, ABS
Resins, MBS resins, polyester resins, polyamide resins and the like can be used alone or in combination of two or more.

As the neutral salt of alkylbenzene sulfonic acid, a neutral salt of alkylbenzene sulfonic acid having an alkyl group having 6 to 16 carbon atoms can be used alone or in combination of two or more kinds. The Na salt is particularly preferably used as the neutral salt. As the water-repellent compound, fatty acids having 10 to 18 carbon atoms and their sodium salts, potassium salts, lithium salts,
Calcium salt, zinc compound or composite metal soap of these, wax, fluid paraffin, synthetic wax such as polyethylene wax, silicone (organopolysiloxane)
Etc. can be used alone or in combination of two or more.

The content of the alkylbenzene sulfonate in the composition of the present invention is preferably 8 to 30% by weight, more preferably 9 to 2
It is 0% by weight. A composition having an alkylbenzene sulfonate content of less than 8% by weight has a small cleaning effect, and a composition having an alkylbenzene sulfonate content of more than 30% has remarkable foaming at the stage of preparing granules thereof. Both are not suitable because granulation is extremely difficult.

The content of the water repellent compound is preferably 0.5 to 10% by weight.
The water-repellent compound acts as a lubricant in the extruder at the time of producing the thermoplastic resin composition of the present invention, but if the content is less than 0.5% by weight, the lubrication effect is small and the foaming becomes severe so that granulation becomes impossible. Become. Further, if the content of the water repellent compound exceeds 10% by weight, the lubricity is too strong, and it becomes difficult to discharge the compound sufficiently blended at the time of granulation.

The thermoplastic resin composition of the present invention may contain a heat stabilizer for molding, a lubricant, a plasticizer and the like in addition to the above components, if necessary.

The thermoplastic resin composition of the present invention can be prepared by a usual method for producing a thermoplastic resin composition. To give an example,
The hopper of the extruder is filled with the premixed composition, and the molten composition is discharged by the heated extruder,
The strands are cut to obtain composition particles.

For mixing, an ordinary mixer such as a Hensiel type high speed mixer, a ribbon blender, a tumbler, or a gate mixer can be used depending on the type and shape of the resin. The thermoplastic resin used for preparing the composition of the present invention may be in the form of powder, beads, flakes, or pellets. The neutral salt and water-repellent compound of alkylbenzene sulfonic acid can be used in the form of powder, paste, liquid or the like. As an extruder for granulating the composition, a single-screw extruder, a twin-screw extruder, a co-kneader and the like can be used, but the extruder is not limited thereto. Further, the cut for the granulation strand may be either an underwater cut or an aerial cut.

(Examples) The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The cleaning effect of the thermoplastic resin composition for cleaning the melt-kneading device in Examples and Comparative Examples is the cleaning test carried out according to the following method, in the replacement performed after cleaning using a predetermined amount of the cleaning composition. The evaluation is based on the amount of the displacing resin consumed and the time from the start of supplying the cleaning thermoplastic resin composition to the disappearance of the coloring of the displacing resin discharged.

Cleaning Test Method Used to extrude a thermoplastic resin composition containing 2% of phthalocyanine blue as a colorant and contaminated, L / D is 3
When 250 g of thermoplastic resin for cleaning is supplied to a single-screw extruder having a cylinder diameter of 0 and a cylinder diameter of 35 mm, the screw is rotated, and the rotation of the screw is shortened when the thermoplastic resin begins to be discharged from the die of the extruder. Time (1-5 minutes)
Stop. Then, the same type of thermoplastic resin as that used in the cleaning resin composition was supplied as a replacement for restarting the rotation of the screw, and the amount of replacement resin consumed until the discharged strand became colorless and decolorization. Measure the time to do.

In yet another example, maleic anhydride is used in place of phthalocyanine blue as a pollution source, and evaluation is made by the consumption amount and time of the replacement resin until the peculiar pungent odor disappears.

Example 1 Polypropylene resin (Chisopolypro (registered trademark) K1
016) 4.5 kg, sodium decylbenzenesulfonate 0.45 kg, and calcium stearate 0.05 kg were stirred in a high-speed mixer with an internal volume of 20 at a rotation speed of 500 rpm for 3 minutes. This mixture was fed to an extruder granulator having an L / D of 20 and a cylinder diameter of 20 mm, and the cylinder temperature was 200
C., die temperature 190.degree. C., screw rotation speed 60 rpm, strands were extruded, cooled in a water bath and cut with a pelletizer to obtain a milky white granular thermoplastic resin composition.

Using the composition 4 days after granulation, an extruder cleaning test was carried out on an extruder soiled with a polypropylene resin of the same kind containing 2% of phthalocyanine blue. Extruder cylinder temperature 2
After the cleaning resin composition was supplied at 20 ° C., the rotation of the extruder screen was temporarily stopped and the cleaning composition was allowed to stand in the extruder for 5 minutes. The required amount of replacement resin is 0.5 kg,
The time required for color change was 11 minutes.

Example 2 The cleaning composition granulated in Example 1 was subjected to the same cleaning test as in Example 1 after 90 days had passed in a three-layer paper bag. The amount of replacement resin required for color change was 0.5 kg, and the required time was 12 minutes.

Example 3 2.5% maleic anhydride instead of phthalocyanine blue
Was conducted in the same manner as in Example 2 except that the cylinder temperature was 190 ° C. for the cleaning test of the extruder. The required amount of the replacement resin was 0.3 kg and the holding time was 8 minutes until the extruded product having no pungent odor was extruded.

Example 4 Polyethylene resin (Chisopolyethyl (registered trademark) M85
0) 3.8 kg, sodium tridecylbenzenesulfonate 0.9 kg, zinc stearate 0.2 kg, polyethylene wax (number average molecular weight 1500) 0.1 kg
After mixing in the same manner as above, the mixture was fed to an extruder having a cylinder temperature of 220 ° C., a die temperature of 210 ° C., and a screw rotation speed of 60 rpm to obtain a milky white pellet.

To an extruder contaminated with a polyethylene resin containing 2% of phthalocyanine blue, 250 g of the above-mentioned cleaning resin composition which had been 5 days after granulation was supplied, and the cylinder temperature was 230.
A washing test was conducted by leaving the temperature at 3 ° C. for 3 minutes after the screen was temporarily stopped. The required amount of the polyethylene resin for replacement was 0.3 kg and the required time was 7 minutes.

Example 5 ABS resin (manufactured by Asahi Kasei Co., Ltd., Stairaysk 200) 4.
2kg, sodium decylbenzenesulfonate 0.6kg,
Granulation was performed under the same extruder operating conditions as in Example 3 using 0.1 kg of fluid paraffin (ISO VG 100 applicable product) and 0.1 kg of stearic acid to obtain a milky white pellet. 15
Using this pellet after a lapse of time, a cleaning test was conducted on an extruder contaminated with the same ABS resin containing 2% of phthalocyanine blue. The results are shown in Table 1 together with the results of Examples 1-5.

Example 6 The same washing test as in Example 2 was repeated, and the resin strand discharged was cut to obtain 560 g of pellets. 150 g of this pellet was prepared in Example 2 and a mixture with 100 g of washing pellets after 90 days was used in Example 1
A washing test was conducted under the same extruder operating conditions as described above. The consumption of replacement polypropylene resin is 0.6 kg, and the time required is 1
It took 3 minutes.

Comparative Example 1 A cleaning test was performed under the same conditions as in Example 1 except that the thermoplastic resin composition of the present invention was not used. As a result, the amount of replacement resin required for color change was 13.0 kg and the time was 1 hour and 28 minutes.

Comparative Example 2 The washing resin mixture prepared by a high-speed mixer in the same manner as in Example 1 was packed in a three-layer paper bag as it was without being granulated and left for 90 days in the room. A cleaning test was performed using this mixture instead of the cleaning composition in Example 1.
The amount of replacement resin required for color change was 7.2 kg, and the required time was 4
It took 8 minutes.

Comparative Example 3 A washing test was conducted under the same conditions as in Example 3 except that the thermoplastic resin composition of the present invention was not used. The amount of replacement resin required for color change was 5.2 kg, and the time was 30 minutes.

The results of the comparative example are shown in Table 1 as in the example.

(Effects of the Invention) By using the thermoplastic resin composition provided by the present invention, an extremely effective method for cleaning a molding machine at the time of grade switching in plastic processing has been realized. That is, by using a small amount of the resin composition of the present invention, it is possible to significantly reduce the consumption amount as compared with the case where the molding machine is washed only by the replacement with the resin supplied later. Taking the cleaning of the extruder as an example, when the composition of the present invention is used in combination as compared with the color change only by the substitution,
The required amount of the replacement resin can be reduced to 1/10 or less, and the time required for color change can be reduced to 1/5 or less.

The composition of the present invention has water repellency, has almost no deterioration in cleaning effect even after storage for 3 months, and is a cleaning composition with good storage stability that can withstand long-term storage.

In addition, when used for cleaning extruders that have a peculiar odor such as a maleic anhydride-containing thermoplastic resin, it is possible to drastically reduce the amount of odorous discharge and shorten the time required for grade switching. Therefore, it has a ripple effect of improving the working environment.

Furthermore, the replacement resin used once can be used as a part of the cleaning resin, and the possibility of reuse of the replacement resin can be expected.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location // (C11D 10/02 1:22 7:26 7:24)

Claims (3)

[Claims] 1. A melt-kneading apparatus comprising 60 to 90.5% by weight of a thermoplastic resin, 8 to 30% by weight of a neutral salt of alkylbenzenesulfonic acid, and 0.5 to 10% by weight of a water repellent compound. A thermoplastic resin composition for cleaning. 2. A thermoplastic resin for washing a melt-kneading device according to claim 1, wherein the neutral salt of alkylbenzenesulfonic acid is sodium alkylbenzenesulfonate having an alkyl group having 6 to 16 carbon atoms. Composition. 3. The water repellent compound according to claim 1 or 2, wherein the water repellent compound is at least one selected from higher fatty acid metal salts, complex metal soap thereof, wax, liquid paraffin, synthetic wax and silicone. A thermoplastic resin composition for cleaning a melt-kneading device.