JPH0399822A - Purging agent of extruder - Google Patents

Abstract

PURPOSE:To remove the carbonized resin bonded to a screw, to reduce the load when the screw is pulled out and to exclude a purging agent itself from the screw by preparing the purging agent from a composition consisting of an olefinic resin, a crosslinked olefinic resin, a nonionic surfactant and metal soap in respective specific amounts and setting the melt flow index of the composition to a specific value range. CONSTITUTION:The purging agent of an extruder consists of 10 - 50 pts.wt. of an olefinic resin, 10 - 80 pts.wt. of a crosslinked olefinic resin, 1 - 10 pts.wt. of a nonionic surfactant and 5 - 30 pts.wt. of metal soap. The melt flow index of this composition is set to 0.05 - 15 g/10 min. The purging agent composition for washing the extruder characterized by that the residual resin bonded to the screw of the extruder is removed and the screw is easily drawn out and the purging agent itself can be extruded when the extruder is washed is obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a purging agent for an extruder, and more specifically, when cleaning an extruder, it removes residual resin attached to the screw and prevents the screw from being removed. The present invention relates to a purging agent composition for cleaning an extruder which can be easily removed from the screw.

Prior Art] After plastic processing using an extruder, burnt carbonized resin remains attached to the screw.

You can remove the screw and use a brush to polish it off, but if there is residual resin on the screw,
Extracting the screw itself requires a great deal of effort, and even if the screw is extracted, polishing the screw is extremely difficult.

Therefore, in order to easily remove the screw, a removal agent is poured into the cylinder of the extruder to wash out the resin remaining on the screw, and then the screw is removed.

In this case, it is undesirable for resin to remain on the screw when using the removal agent.
It is necessary that the removal agent can be removed almost completely, so that the removal of the screw is not burdened, and that the removal agent itself is expelled from the screw.

Conventionally, the work of extracting the screw was carried out after pouring an extremely small acrylic resin with a melt flow index (Ml>) into the lrl from which the screw was extracted to wash out any residual resin that had adhered to the screw. was.

Similarly, cross-linked polyethylene resin was also used as a purging agent (Japanese Patent Laid-Open No. 54-29
Publication No. 351).

Furthermore, JP-A-58-149998 discloses a nonionic surfactant 1- whose decomposition initiation temperature is 200°C or higher.
A detergent composition is described which comprises 15 parts of WL, 5 to 30 parts of metal soap, 20 to 7 parts of inorganic filler, and 20 to 70 parts of olefinic resin.

[Problems to be Solved by the Invention] However, if the Ml of the resin for purging is large, the cleaning resin itself may adhere to the screw.

Furthermore, when a crosslinked polyethylene resin is used as the sole purging agent, there is a problem in that the load during operation of the extruder becomes large.

Furthermore, in the above-mentioned cleaning composition containing an inorganic filler, the residual resin attached to the screw is partially washed away and remains, as shown in the comparative example below.

Therefore, the products described in these publications sufficiently perform the function described in 1ii, that is, the removal agent itself is removed from the screw, the residual resin is almost completely eliminated, and the screw can be pulled out with a reduced load. I can't.

It is an object of the present invention to provide a cleaning agent that can sufficiently fulfill the above-mentioned functions in view of the prior art.

[Means for Solving the Problems] The purging agent of the present invention to achieve the above object contains 10 to 50 width parts of an olefin resin, 10 to 80 parts of a crosslinked olefin resin, and 1 part of a nonionic surfactant. -10 parts by weight and 5 to 30 parts by weight of metal soap, and the melt flow index of the composition is 0.05 to 15.
In particular, the combination of an olefin resin and a crosslinked olefin resin is characterized in that it is in the range of g/10 minutes;
It is characterized by not containing an inorganic filler and by having a melt flow index (M) of the purging agent composition within a specific range.

Examples of the olefin resin used in the present invention include polyethylene resins, and specific examples thereof include polyethylene, copolymers of ethylene and a-olefins such as propylene, 1-butene, and -pentene, or copolymers of ethylene and It includes a copolymer of ethylene and a copolymer copolymerizable therewith, such as a copolymer with a vinyl monomer such as vinyl acetate and having an ethylene content of 50VIL% or more. As the olefin resin, other olefin resins such as polypropylene and polybutene may be used.

Alternatively, it may be one obtained by decrosslinking crosslinked polyethylene.

Examples of the crosslinked olefin resin used in the present invention include those obtained by crosslinking the above-mentioned olefin resins. Crosslinking can be performed by various crosslinking methods such as electron beam crosslinking. The crosslinking ratio (degree of crosslinking) can be expressed by the gel fraction, and the gel fraction is expressed by the proportion of the insoluble portion by boiling and extraction with xylene.

For the desired purpose of the present invention, the gel fraction is 10% or more, preferably 15-80%, particularly preferably 20-60%.

In the present invention, the crosslinked olefin resin includes 1, for example, rolled and/or stretched sheets and films crosslinked by irradiating a polyethylene resin original sheet with an electron beam, or scraps such as edges and slits thereof. can be used by crushing it into pellets.

Nonionic surfactants used in the present invention include polyoxyethylene alkyl ethers such as polyoxyethylene stearyl ether, polyoxyethylene phenyl ethers such as polyoxyethylene nonylphenyl ether, sorbitan fatty acid esters such as sorbitan monostearate, polyoxyethylene phenyl ethers such as polyoxyethylene nonylphenyl ether, sorbitan fatty acid esters such as sorbitan monostearate, Ethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, glycerin fatty acid esters such as stearic acid monoglyceride, polyoxyethylene fatty acid esters such as polyethylene glycol monolaurate, polyoxyethylene polyoxypropylene block polymers, etc. can be mentioned.

Metal soaps used in the present invention include calcium straight chain aliphatic monocarboxylic acids having 12 to 18 carbon atoms, such as lauric acid, valmitic acid, stearic acid, oleic acid, and lysyllic acid.

Examples include metal salts such as zinc, magnesium, barium, and aluminum.

In the present invention, the content of the olefin resin is 10 to 50% in the IL part of the purging agent composition consisting of the following components.
It needs to be the WL part.

The olefin resin plays the role of holding metal soaps and nonionic surfactants and uniformly dispersing them. Therefore, if the olefin resin is removed, metal soaps and surfactants will seep out of the system even at low temperatures of 200° C. or lower, resulting in very poor thermal stability of the cleaning agent.

Therefore, if the olefin resin is less than 10 parts by weight, it is difficult to fulfill the above role, and metal soaps etc. leached out.
It worsens the heat stability of the purging agent, and on the other hand, 50
When the Wt part is exceeded, the proportion of the crosslinked olefin resin is lowered, and it becomes difficult to sufficiently perform the function of removing the purge itself from the screw.

In the present invention, the content of the crosslinked olefin resin is required to be 10 to 80 parts by weight in the entire composition.

Cross-linked olefin resin has a high gel fraction of 25
It does not melt even at temperatures below 0°C, giving the cleaning agent mechanical cleaning power and improving the releasability of the cleaning agent itself. Furthermore, the cleaning agent itself is a major factor in being excluded from the screw.

When the crosslinked olefin resin deviates from this range, it becomes difficult to sufficiently exhibit such effects and to sufficiently fulfill the above-mentioned functions when forming the composition of the present invention excluding the inorganic filler.

In the present invention, the content of the nonionic surfactant needs to be 1 to 101 parts in the total composition.

If the nonionic surfactant is added in excess of the towt part of the entire composition, the slipperiness may become too large and the resin attached to the screw may not be extruded from the screw due to slipping. Below +Wt part,
Each component is not uniformly dispersed, and the cleaning effect is significantly reduced.

In the present invention, the content of metal soap is 5 to 5 in the total composition.
It is necessary that the area is 3 CIL. If it is less than 5 CIL, the mold releasability of the carbonized resin attached to the screw will be poor and the cleaning effect will be poor. On the other hand, if it exceeds 3 CIL, the lubricity will be too large and slip. This phenomenon occurs, impairing the cleaning effect.

Ml of the purging agent composition of the present invention (JIS K676
0, temperature 190"C9 cargo city 2.16) measured at tg) is 0
．． 05-15g/TO min preferably 0.1-10g71
It must be 0 minutes.

If the M1 is less than 0.05 g/I 0 min, the load on the motor during extruder operation becomes too large;
When the amount exceeds 15 g/10 minutes, the purging agent melts too much and the cleaning effect deteriorates.

The purging agent of the present invention can be used, for example, in a -shaft extruder, an L-shaft extruder,
It can be made into a pellet shape using a kneader such as a kneader, and poured into the cylinder of an extruder before the extruder screw is removed.

[Examples] Next, the present invention will be described based on Examples and Comparative Examples.

The cleaning effect of the purging agent was evaluated under the following conditions.

Moreover, the percentage is based on heavy M.

Extruder used: 50 mm φ Hanging shaft extruder Cleaning effect test method: After discharging 3 g of high-density polyethylene (trade name Tonen Polyethylene HY OI, manufactured by Tonen Petrochemical Industries, Ltd.), 200 g of each press and wash were poured. 1) Measure the force required to pull out the screw (hereinafter referred to as extrusion resistance) using a spring scale, (2) Visually observe the state of adhesion of the cleaning agent to the screw (O: no adhesion, △D adhesion to some parts) , x: adhered to the entire surface), and (3) motor load (current value) while the cleaning agent was flowing.

Cylinder temperature: 180/ZOO/220/
220/220°C rotary scattering; 60 rpm Examples 1 to 6. Comparative Examples 1 to 7° High-density polyethylene (H
I) P E ) with various gel fractions of crosslinked resin [crushed crosslinked polyethylene film (passed through 5 meshes)], nonionic surfactant (polyoxyethylene stearyl ether) and metal soap (zinc stearate). 1st
After tri-blending in the proportions shown in the table, the mixture was kneaded and pelletized at 300° C. using a 44 mmφ co-directional twin-screw extruder to prepare a purging agent.

Table 1 shows the test results for MI and cleaning effectiveness of the various purging agents obtained.

Comparative Example 8 Using a commercially available product (olefin resin as a base resin to which calcium carbonate, metal soap, and surfactant were added), Ml and cleaning effect tests were conducted in the same manner as in Example 1, and the results were as follows: are also listed in Table 1.

/ / [Effects of the Invention] According to the present invention, the carbonized resin attached to the screw can be almost completely removed, and f'l (1) when removing the screw is reduced, and the purge agent itself is I was able to eliminate it from the screw.

Claims (1)

[Claims] 1. 10 to 50 parts by weight of olefin resin, 10 to 80 parts by weight of crosslinked olefin resin, 1 to 10 parts by weight of nonionic surfactant
10 parts by weight and 5 to 30 parts by weight of metal soap,
and the melt flow index of the composition is 0.0
Extruder purging agent in the range of 5-15 g/10 minutes.