JPH02180941A - Thermoplastic resin composition for washing - Google Patents

Abstract

PURPOSE:To obtain the title composition which can effectively function for washing a molding machine in the changeover of grades in plastic processing by mixing a thermoplastic resin with a Ca salt of a higher fatty acid monoglyceride borate and an inorganic filler. CONSTITUTION:Desirably 45-95wt.% thermoplastic resin (e.g. PE) is mixed with desirably 1-20wt.% Ca salt of a higher fatty acid monoglyceride borate of the formula (wherein R is a 11-17C alkyl), e.g. Ca salt of stearic monoglyceride borate, and desirably 2-45wt.% inorganic filler (e.g. silicic anhydride).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cleaning resin composition used in a thermoplastic resin molding machine.

[Conventional technology]

In plastic molding and processing, several measures are taken to eliminate the influence of the preceding product when changing products. In particular, when processing colored products, changing the color from dark grades such as blue or black to light grades such as white requires complicated work such as cleaning the inside of the molding machine with cleaning resin and disassembling and cleaning the molding machine. The reality is that we are forced to suspend production due to this. 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 brushing, etc., and then reinstall the screw. Using resin to replace the previous product without removing the screw requires a large amount of resin for cleaning, and the complicated structure inside the extruder cannot be cleaned, resulting in coloring of the subsequent resin. There is a problem. Cleaning compounds are used to overcome these problems. The idea is to use a cleaning compound to make it easier to remove residue inside the extruder, and to use a small amount of replacement resin to change product types. There are cleaning compounds that contain lubricants such as stearic acid and those that use acrylic resin with a high melting temperature, but the former are not sufficiently effective, and the latter have a strong odor. In addition, due to the high melt viscosity, there is a drawback that the cleaning compound must be used after removing the die, breaker plate, wire gauze, etc., resulting in complicated operations.

Additionally, cleaning compounds containing glass fibers and the like have the disadvantage of wearing out the extruder screws and cylinders.

[Problem to be solved by the invention]

As is clear from the above, the purpose of the present invention is to
After cleaning with a cleaning thermoplastic resin composition, by using a small amount of replacement resin, the resin of the previous type remaining in the molding machine can be removed in a short time with a simple operation. An object of the present invention is to provide a plastic resin composition.

[Means to solve the problem]

As a result of various studies on cleaning methods for molding machines, the inventors discovered that a resin composition prepared by mixing a thermoplastic resin, a calcium salt of boric acid ester of higher fatty acid monoglyceride, and an inorganic filler and granulating it has an excellent cleaning effect. They discovered this and completed the present invention.

That is, the present invention is a cleaning thermoplastic resin composition comprising a thermoplastic resin, a calcium salt of a boric acid ester of a higher fatty acid monoglyceride having the following structural formula, and an inorganic filler.

However, R: alkyl group (carbon number 11 to 17), thermoplastic resin 45 to 95% by weight, calcium salt of boric acid ester of higher fatty acid monoglyceride 1 to 20% by weight,
It is a resin composition obtained by mixing and granulating 2 to 45% by weight of an inorganic filler.

Thermoplastic resins used in the composition of the present invention include polyolefins such as polyethylene, polypropylene, polybutene, and polymethylpentene, polyvinyl chloride, polyvinyl acetate, polystyrene, polyacrylonitrile, or copolymers thereof, and ABS. Resin, MBS resin, polyester resin, polyamide resin, etc. can be used alone or in combination of two or more.

Further, the calcium salt of boric acid ester of higher fatty acid monoglyceride used in the composition of the present invention is made from higher fatty acid monoglyceride having an alkyl group having 11 to 17 carbon atoms and a mixed higher fatty acid monoglyceride of two or more of these. It is a calcium salt of boric acid ester.

The content of calcium salt of boric acid ester of higher fatty acid monoglyceride used in the composition of the present invention is preferably 1 to 20% by weight. If the content is less than 1%, the cleaning effect will be small;
If the content exceeds 20%, the slipperiness is too strong, making it difficult to discharge the compound during granulation, which is not suitable.

Inorganic fillers include calcium carbonate, silicic anhydride, and alumina. and talc, etc., and the content thereof is preferably 2 to 45% by weight.

If the content is less than 2%, the cleaning power due to friction is small, and 45%
If the content exceeds the above, it becomes difficult to mix the inorganic filler uniformly, and a surging phenomenon occurs during granulation, which is not suitable.

In addition to the above-mentioned components, the composition of the present invention may optionally contain a molding heat stabilizer, a lubricant, a surfactant, and the like. Heat stabilizers include phenolic compounds such as bisphenol A, calcium stearate, metal soaps such as zinc stearate, organic tin compounds such as dibutyltin malate, and lubricants include higher fatty acids such as stearic acid, carnauba wax, and polyethylene wax. Waxes such as
Furthermore, examples of the surfactant include anionic surfactants such as sodium alkylbenzenesulfonate and nonionic surfactants such as polyethylene glycol.

The composition of the present invention can be prepared by a conventional method for producing thermoplastic resin compositions.

For example, a premixed composition is filled into the hopper of an extruder, the molten composition is discharged by a heated extruder, and the strands are strained and strained to obtain a pelletized composition. For mixing, a conventional mixer such as a Henschel type high-speed mixer, ribbon blender, or tumbler can be used depending on the type and shape of the resin. The thermoplastic resin used can be in the form of powder, beads, flakes, or pellets. The extruder is not particularly limited, and may be a single screw extruder, a twin screw extruder, a co-kneader, or the like. The strands for granulation may be cut underwater or in the air.

〔Example〕

The present invention will be specifically explained below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In Examples and Comparative Examples, the cleaning effect of the thermoplastic resin composition for cleaning was tested according to the following method. The evaluation is based on the amount of replacement resin consumed in the cleaning test and the time from the start of supply of the cleaning thermoplastic resin composition until the replacement resin contaminated by the preceding resin loses its color.

Cleaning test method Using a 35 ton injection molding machine, 30% of the colored resin was
Supply 0g and inject. Next, 100 grams of a cleaning thermoplastic resin composition is supplied, and a replacement resin is further supplied, and injection molding is repeated until the replacement resin loses its color.

Measure the amount of replacement resin consumed and the time until the color disappears.

(Example)) Polyethylene (melt index (JISK6760
: 190℃, 2.16kgf) 1.5g/l, 0m
1n high density polyethylene homopolymer) 4.68kg
, stearic acid monog, 0.07 kg of calcium salt of boric acid ester of receride, 0.15 kg of silicic anhydride (particle size 3.5 microns or less), and polyethylene wax (
0.1 kg (number average molecular weight: 1500) was mixed by stirring for 3 minutes at a rotational speed of 50 rpm using a high speed mixer having an internal volume of 20 liters.

This mixture was supplied to an extruder with an L/D of 28 and a cylinder diameter of 35 mm, with a cylinder temperature of 230°C and a die temperature of 22°C.
The strands were extruded at 0° C., cooled in a water bath, and cut with a paytizer to obtain a milky white, granular thermoplastic resin composition. Using this composition, carbon black 1
A cleaning test was conducted on an injection molding machine soiled with ABS resin containing %.

The composition was fed and washed at the cylinder temperature of the molding machine at 230°C, and polypropylene (melt flow rate
(J l5K6758: 230 ℃,
2, 16kgf) 5g/aln)
Replaced with. The amount of replacement resin required was 260 grams, and the time required for washing was 18 minutes.

(Example 2) Polypropylene (melt flow rate (JISK675
8: 230℃, 2.16kgf) 5y/a+in
) 3. 60 kg, calcium salt of boric acid ester of stearic acid monoglyceride 0.25 kg.

Talc 1.00kg, calcium stearate 0.05
kg, polyethylene wax (number average molecular weight 1500)
After 0.1 kg was mixed in the same manner as in Example 1, it was granulated at a cylinder temperature of 220°C and a die temperature of 210°C to obtain milky white pellets.

A cleaning test was conducted under the same conditions as in Example 1. The amount of replacement resin required was 220 grams, and the time required for washing was 16 minutes.

(Example 3) Polystyrene (Styron 600 manufactured by Asahi Kasei ■) 4.10
kg, calcium salt of boric acid ester of lauric acid monoglyceride 0.50 kg, alumina (manufactured by Sumitomo Chemical A)
L-32) 0.25kg, calcium stearate 0
．． 06kg, polyethylene wax (number average molecular weight 15
00) 9 kg of O, O were mixed in the same manner as in Example 1, and granulated at a cylinder temperature of 220°C and a die temperature of 220°C.
An off-white pellet was obtained. As in Example 1, a cleaning test was conducted on an injection molding machine contaminated with ABS resin containing 1% carbon black. The composition was supplied and washed at a cylinder temperature of 230°C of a molding machine, and replaced with polystyrene (Styron 600 manufactured by Asahi Kasei ■). The required amount of replacement resin is 2
00g, and the time required for washing was 15 minutes.

(Example 4) Polyvinyl chloride (average weight 800) 3.95 kg 1 Calcium salt of boric acid ester of palmitic acid monoglyceride 0.35 kg, calcium carbonate 0.55 kg, calcium stearate 0.07 kg.

Zinc stearate 0.05kg, stearic acid 0.03
kg, mixed in the same manner as in Example 1 and cylinder temperature 180
The pellets were granulated at a die temperature of 170°C to obtain white pellets. This composition was used in a cleaning test on an injection molding machine soiled with a polyvinyl chloride compound containing 1% carbon black.

The composition was fed and washed at a molding machine cylinder temperature of 180 DEG C. and replaced with ethylene-vinyl acetate copolymer (Ultracene 631 manufactured by Tosoh Corporation).

The amount of replacement resin required was 240 grams, and the time required for washing was 17 minutes.

(Example 5) Ethylene-vinyl acetate copolymer (Ultrasen 631 manufactured by Tosoh Corporation) 3.30 kg, calcium salt of boric acid ester of stearic acid monoglyceride 0.60 kg, calcium carbonate 1.00 kg, calcium stearate 0
．． 05kg, zinc stearate 0.05kg Example 1
The mixture was mixed in the same manner as above and granulated at a cylinder temperature of 190°C and a die temperature of 180°C to obtain white pellets. A cleaning test was conducted using this composition under the same conditions as in Example 4.

The amount of replacement resin required was 160 grams, and the time required for washing was 13 minutes.

(Example 6) ABS resin (Stylac 200 manufactured by Asahi Kasei) 3.80
kg, calcium salt of boric acid ester of stearic acid monoglyceride 0.35 kg, calcium carbonate 0.50
kg, alumina (AL-32 manufactured by Sumitomo Chemical ■) 0.
15 kg of zinc stearate, 0.05 kg of zinc stearate, and 0.15 kg of polyethylene wax (number average molecular weight 1500) were mixed in the same manner as in Example 1, and granulated at a cylinder temperature of 230°C and a die temperature of 220°C. Using this composition, a cleaning test was conducted under the same conditions as in Experiment 3. The amount of replacement resin required was 180 grams, and the time required for washing was 14 minutes.

(Example 7) Polyethylene (melt index (JISK6760
: 190°C, 2.16 kgf) 1.5 g/]01n high density polyethylene homopolymer) 2.35 kg, calcium salt of boric acid ester of stearic acid monoglyceride 0.40 kg, calcium carbonate 2.10 kg, zinc stearate 0. 0.5 kg and 0.10 kg of polyethylene wax (number average molecular weight 1500) were mixed in the same manner as in Example 1, and the cylinder temperature was 230°C and the die temperature was 220°C.
Granulation was carried out at ℃. A cleaning test was conducted using this composition under the same conditions as in Example 1. The amount of replacement resin required was 160 grams, and the time required for washing was 13 minutes.

(Example 8) Polypropylene (melt flow rate (JISK675
8: 230℃, 2.16kgf)5+r/In1n
) 2. 60 kg, calcium salt of boric acid ester of stearic acid monoglyceride 0.85 kg.

Talc 0.70kg, calcium carbonate 0.70kg, zinc stearate 0.05kg, polyethylene wax (
Number average molecular weight 1500) 0. 1 okg was mixed in the same manner as in Example 1, and the cylinder temperature was 220°C and the die temperature was 2.
Granulation was carried out at 10°C. A cleaning test was conducted using this composition under the same conditions as in Example 1. The required amount of replacement resin is 100
grams, and the time required for washing was 10 minutes.

(Comparative Example 1) A cleaning test was conducted 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 was 2,320 grams, and the time required for cleaning was 1 hour and 56 minutes.

(Comparative Example 2) (Example of boric acid ester deficiency in higher fatty acid monoglyceride) Polypropylene (melt flow rate (JISK675
8: 230°C, 2. 16kgf)
5 z/ll1in) 4. 62 kg, calcium salt of boric acid ester of stearic acid monoglyceride 0.03 kg.

Anhydrous silicic acid (particle size 3.5 microns or less) 0.15 kg.

0.10 kg of calcium stearate and 0.10 kg of polyethylene wax (number average molecular weight 1500) were mixed in the same manner as in Example 1, and granulated at a cylinder temperature of 220°C and a die temperature of 210°C. Example 1 using this composition
A cleaning test was conducted under the same conditions. The amount of replacement resin required was 860 grams, and the time required for washing was 48 minutes.

(Comparative Example 3) (Example of excess thermoplastic resin in thermoplastic resin composition and insufficient inorganic filler) Polyethylene (melt index (JISK676
0:190℃, 2.16kgf) 1.5g/10m1
n) high-density polyethylene homopolymer) 4.82 kg
, 0.06 kg of calcium salt of boric acid ester of stearic acid monoglyceride, 0.02 kg of silicic anhydride (particle size 3.5 microns or less), and 0.10 kg of polyethylene wax (number average molecular weight 1500) were mixed in the same manner as in Example 1. Cylinder temperature 220℃1, die temperature 210℃
It was granulated with A cleaning test was conducted using this composition under the same conditions as in Example 1. The amount of replacement resin required was 880 grams, and the time required for washing was 49 minutes.

The compositions and cleaning test results of Examples 1 to 8 and Comparative Examples 1 to 3 are summarized in Table 1 below.

〔Effect of the invention〕

By using the cleaning thermoplastic resin composition provided by the present invention, a highly effective method for cleaning molding machines during grade change in plastic processing has been realized. That is, by using a small amount of the composition of the present invention, the amount consumed can be significantly reduced compared to when cleaning the molding machine is performed only by replacing the molding machine with a resin supplied later. Taking an injection molding machine as an example, if the composition of the present invention is used in combination with the color change using only the subsequent resin,
The amount of replacement resin required could be reduced to 1/8 or less, and the time required for color change could also be reduced to 1/6 or less.

Claims (1)

[Claims] 1. A thermoplastic resin composition for cleaning comprising a thermoplastic resin, a calcium salt of a boric acid ester of a higher fatty acid monoglyceride having the following structural formula, and an inorganic filler. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ R: Alkyl group (carbon number 11-17) 2. Thermoplastic resin 45-95% by weight, calcium salt of boric acid ester of higher fatty acid monoglyceride 1-20% by weight, and inorganic The thermoplastic resin composition for cleaning according to claim 1, which contains 2 to 45% by weight of a filler. 3. The thermoplastic resin composition for cleaning according to claim 1 or 2, wherein the thermoplastic resin is polyethylene, polypropylene, polystyrene, polyvinyl chloride, ethylene-vinyl acetate copolymer, or ABS resin. 4. The thermoplastic resin composition for cleaning according to claim 1 or 2, which is formed into pellets by melt-kneading.