JP2001279035A - Cleaning resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaner which can remove a used resin left in a molding machine in a small amount in a short time to enable the employment of the molding machine for a normal molding process, when the used resin is replaced by a resin having a different color. SOLUTION: This resin composition for cleaning, obtained by compounding 100 pts.wt. of a resin component comprising 10 to 99 pts.wt. of an ethylene- unsaturated ester copolymer and 90 to 1 pts.wt. of polyethylene having a MFR of <=1.0 g/10 min with 0. 1 to 20 pts.wt. of a powdery inorganic filler and 0.1 to 10 pts.wt. of a lubricant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning resin composition for removing contamination caused by a preceding resin in a molding machine in plastic molding. In particular, the present invention relates to a cleaning resin composition which exhibits an effect by using a small amount at the time of color change in molding a thermoplastic resin, particularly, a polyolefin.

[0002]

2. Description of the Related Art In the plastic molding industry, many resins, such as general-purpose resins and engineering plastics, are used as raw materials, and each of them contains various pigments and dyes in order to enhance design properties. Has been used as In particular, in recent years, the types of coloring agents used have been increasing due to diversification of market needs. In such multi-product small-volume production-oriented molding, the opportunity to use the same molding machine is inevitably increasing.

[0003] Conventionally, in the case of performing resin change or color change in extrusion molding or injection molding, attempts have been made to reduce the time and resin loss involved in the change by using a cleaning agent. In other words, in order to improve work efficiency, it is a major issue to remove the previously used resin from the molding machine so that a regular molded product can be obtained in as short a time as possible, and purged products generated during cleaning are used as products. Instead, it is an industrial waste, and there has been a demand for effective cleaning using a small amount of a cleaning agent. However, as a matter of course, suitable cleaning agents differ depending on the type of resin to be cleaned and the type of resin to be newly molded, and there is no universal cleaning agent. In addition, many of the conventionally proposed cleaning agents are focused exclusively on resin replacement, and are not necessarily optimal for color replacement.

[0004] For example, the applicant has proposed a cleaning agent suitable for purging an ethylene / unsaturated carboxylic acid copolymer, such as polyethylene, ethylene / unsaturated carboxylic acid ester copolymer, inorganic filler, chemical foaming agent and slip agent. A resin composition comprising is proposed in JP-A-7-9531. It is effective to apply this cleaning agent for changing the color of polyolefin, but it causes smoke and odor at the time of purging, and requires the use of an expensive chemical foaming agent.

[0005]

The inventors of the present invention have sought to find a less expensive and less expensive cleaning agent which is effective for a small amount of short-time cleaning for color change of polyolefin. As a result, they have found that the following resin compositions are effective.

[0006]

That is, the present invention comprises 10 to 99 parts by weight of an ethylene / unsaturated carboxylic acid ester copolymer and 90 to 1 part by weight of a polyethylene having a melt flow rate of 1.0 g / 10 minutes or less. The present invention relates to a cleaning resin composition comprising 0.1 to 20 parts by weight of a powdery inorganic filler and 0.1 to 10 parts by weight of a lubricant per 100 parts by weight of a resin component. With such a cleaning agent, the colored polyolefin can be purged in a short time and in a small amount without using a foaming agent.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The ethylene / unsaturated carboxylic acid ester copolymer used in the cleaning resin composition of the present invention has an unsaturated carboxylic acid ester content of 2 to 35% by weight, particularly 5 to 25% by weight. % At 190 ° C. and a melt flow rate under a load of 2160 g of 0.01 to 10 g / 10 min, particularly 0.1
It is preferable to use one having a flow rate of ５5 g / 10 min. That is, if the content of the unsaturated carboxylic acid ester in the copolymer is too small, the washing efficiency is reduced, while if the content is too large, odor problems are likely to occur. Also, if the melt flow rate of the copolymer is too high, the washing efficiency is reduced.

The unsaturated carboxylic acid ester in the above copolymer includes methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate,
Examples thereof include methyl methacrylate, isobutyl methacrylate, dimethyl maleate, and diethyl maleate, and an ester of acrylic acid or methacrylic acid having an alkyl group having 1 to 4 carbon atoms is particularly preferable.

In the cleaning resin composition of the present invention, the melt flow rate at 190 ° C. under a load of 2160 g is 1.0 g / 10 min or less, preferably 0.01 g, together with the above-mentioned ethylene / unsaturated carboxylic acid ester copolymer. ~
0.6 g / 10 min, more preferably 0.02 to 0.3 g
/ 10 min polyethylene is used. As such polyethylene, high-density polyethylene, medium-density polyethylene, linear low-density polyethylene, high-pressure low-density polyethylene, and the like can be used.
Most preferred is the use of high density polyethylene of m ³ or more.
If the melt flow rate is higher than the above range, it is difficult to perform the washing in a short time in changing the color of the polyolefin.

The mixing ratio of the ethylene / unsaturated carboxylic acid ester copolymer and polyethylene is such that the total amount of both is 10%.
When the amount is 0 parts by weight, the ratio of the latter is 10 to 99 parts by weight, and the amount of the latter is 90 to 1 part by weight, preferably 50 to 90 parts by weight of the copolymer and 50 to 90 parts by weight of the polyethylene. Parts. By using such a ratio, in the color change of the polyolefin, it is possible to perform the washing with a small amount of use and in a short time.

The detergent of the present invention contains a powdery inorganic filler and a lubricant together with the above resin component.

Examples of the powdery inorganic filler include silica, alumina, talc, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, magnesium silicate and synthetic zeolite. As such a powdered inorganic filler, for example, a particle size of 0.1 to 10
Those having a size of about μm can be suitably used.

The lubricant is a generic term for a lubricant, a release agent, a roll release agent and the like, and it is preferable to use a fatty acid type or an alcohol type. Examples of the fatty acid-based lubricant include lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid.
Stearic acid is most preferred because it has good performance and is inexpensive. Examples of alcohols include higher aliphatic alcohols such as cetyl alcohol and stearyl alcohol, and polyethylene glycol having a molecular weight of about 400 to 10,000. Two or more of these lubricants can be used in combination.

The amount of the powdery inorganic filler is 0.1 to 20 parts by weight, preferably 1 to 100 parts by weight based on 100 parts by weight of the total of the ethylene / unsaturated carboxylic acid ester copolymer and polyethylene.
10 parts by weight, and the lubricant is used in a proportion of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight. Washing efficiency can be enhanced by blending an appropriate amount of an inorganic filler and a lubricant, but if the amount of the inorganic filler used is excessive, the melt fluidity is impaired, and it becomes difficult to perform a washing operation smoothly, and If the amount of used is excessive, the lubricity becomes too strong and the effect of adding the inorganic filler is impaired, which is not preferable.

The cleaning resin composition of the present invention may optionally contain additives such as antioxidants, heat stabilizers, and surfactants.

The cleaning resin composition of the present invention is suitable for cleaning various thermoplastic resin moldings. For example, it can be applied to cleaning at the time of color change in molding of polyolefin, polystyrene, AS resin, ABS resin, polyester, polyamide, polycarbonate, polyphenylene oxide, polyvinyl chloride, etc., and is particularly suitable for color change in polyolefin molding. . More specifically, various polyethylenes, polypropylenes, poly-1-
Butene, poly-4-methyl-1-pentene and the like, titanium oxide, inorganic pigments such as carbon black, azo-based,
When manufacturing a molded article or an uncolored molded article colored with an organic pigment such as a phthalocyanine-based, quinacridone-based, perylene-based, isoindolinone-based, or dioxazine-based product, examples of application such as washing at the time of color change may be given. it can.

The molding machine to be cleaned is an extrusion molding machine, an injection molding machine, or the like, and the cleaning is performed at a temperature equal to or higher than the melting point of the cleaning resin composition of the present invention, for example, at a temperature of about 150 to 250 ° C. it can.

[0018]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 Ethyl acrylate content: 15% by weight, melt flow rate: 0.5 g / 10 min, ethylene / ethyl acrylate copolymer: 84 parts by weight, melt flow rate: 0.04 g / 10 min, density: 956 kg / M ³ of high-density polyethylene (trade name: HZ7000F, manufactured by Mitsui Chemicals, Inc.) was melt-mixed with 16 parts by weight, and 100 parts by weight of the resin was mixed with synthetic zeolite (trade name: Shilton JC-5).
0 Mizusawa Chemical Co., Ltd.) 3 parts by weight, 1 part by weight of polyethylene glycol having a molecular weight of 4000, 0.5 part by weight of stearic acid, and an antioxidant (trade name: Irganox 1010)
0.5 part by weight of Ciba Specialty Chemicals Co., Ltd.) was added and melt-mixed to obtain a resin composition for washing.

An extruder (40 mmφ, L / L) equipped with a T die having a die width of 450 mm and a lip clearance of 0.7 mm.
D = 28), and a film was formed in the following procedure. (1) Melt flow rate 7 g / 10 min (230 ° C., 2
A blue masterbatch was dry-blended with polypropylene (trade name: F227, manufactured by Grand Polymer Co., Ltd.) having a load of 160 g) and extruded at 230 ° C. and 100 rpm.
A blue film was formed. (2) Next, 5 kg of the above-mentioned resin composition for washing was flowed at 230 ° C. and 100 rpm for 15 minutes. (3) The same polypropylene as described above was extruded under the conditions of (1), colorless film molding was started, and the color of the sample after a certain time was confirmed. 15 minutes after the start, a colorless film without coloring was obtained.

[Comparative Example 1] In Example 1, after forming a blue film without using a cleaning resin, the appearance of a film obtained by immediately supplying polypropylene for 30 minutes was examined. The color at the center of the film had disappeared, but blue remained at both ends.

Comparative Example 2 The appearance of a film obtained by supplying polypropylene for 60 minutes in Comparative Example 1 was examined. The blue color at both ends of the film remained.

Comparative Example 3 A resin composition for washing was obtained by melt-mixing under the same conditions as in Example 1 except that high-density polyethylene was not used. Using this product, a film was processed in the same procedure as in Example 1. After supplying the cleaning resin,
The color at the center of the film obtained by supplying the polypropylene for 30 minutes had disappeared, but blue remained at both ends.

[Example 2] In Example 1, a linear low-density polyethylene (trade name: Evolu SP1540, manufactured by Mitsui Chemicals, Inc.) manufactured using a metallocene catalyst instead of polypropylene, and having a melt flow rate of 4 g / 10 min.
The same test was performed except that the above test was used. In the same colorless film molding as in the above (3), a colorless film without coloring was obtained 15 minutes after the start.

[Comparative Example 4] In Example 2, after forming a blue film without using a cleaning resin, the appearance of a film obtained by supplying linear low-density polyethylene for 30 minutes immediately was examined. The color at the center of the film had disappeared, but blue remained at both ends.

Comparative Example 5 The appearance of a film obtained by supplying the linear low-density polyethylene in Comparative Example 3 for 60 minutes was examined. The blue color at both ends of the film remained.

[0027]

According to the present invention, it is possible to provide a cleaning resin composition which is useful in changing the color of a thermoplastic resin. By using such a cleaning agent, a regular molded product can be obtained in a short time and with a small amount of use, so that production efficiency can be improved.

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Claims (2)

[Claims] 1. An ethylene / unsaturated carboxylic acid ester copolymer having a melt flow rate of 10 to 99 parts by weight and a melt flow rate of 1.99 parts by weight.
0.1 g of a powdery inorganic filler per 100 parts by weight of a resin component consisting of 90 to 1 part by weight of polyethylene of 0 g / 10 min or less.
A cleaning resin composition comprising-20 parts by weight and 0.1-10 parts by weight of a lubricant. 2. The cleaning resin composition according to claim 1, wherein the polyethylene is a high-density polyethylene.