JP2000037735A - Resin composition for cleaning molding machine and method for cleaning molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition excellent in cleaning ability of a thermoplastic resin molding machine. SOLUTION: The resin composition for cleaning the thermoplastic resin molding machine essentially consists of a compound such as phosphite ester which forms chelate with respect to metal chloride, and a heat-fusible resin such as polyolefin. Further, it may include water and/or anion activator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin composition for cleaning a molding machine and a method for cleaning a molding machine.

[0002]

2. Description of the Related Art Processing of a thermoplastic resin is carried out by an extruder or an injection molding machine. However, since the resin needs to be heated to a molten state, coloring of the resin mainly due to oxidation occurs in the molding machine. Therefore, production has to be stopped due to disassembly and cleaning of the molding machine and cleaning of the molding machine with a large amount of cleaning resin. As a method for solving these problems, use of a cleaning compound has been proposed (for example, JP-A-62-19).
No. 5045).

[0003]

However, although the proposed cleaning compound is effective in reducing the amount of co-washing resin at the time of changing the color of a molded product, the cleaning compound is not suitable for molding machines due to coloring due to oxidation of the resin. With respect to dirt, it was inevitable that the molding machine was disassembled and cleaned (screw and cylinder brushing) even if a washing compound was flowed.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a resin composition comprising a specific compound has an excellent cleaning ability, and have reached the present invention.

That is, the present invention provides a resin composition for cleaning a thermoplastic resin molding machine, comprising a compound (A) which forms a chelate with a metal chloride and a hot melt resin (B).
Further, the present invention provides a method for cleaning a thermoplastic resin molding machine, which comprises passing the resin composition for molding machine cleaning in a molten state through a molding machine (L).

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The compound (A) which forms a chelate with the metal chloride of the present invention includes phosphites, phosphites, polycarboxylic acids and the like. Examples of the phosphorous acid include phosphorous acid and hypophosphorous acid. As phosphites, for example,
Triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, triisodecyl phosphite, tri-2-ethylhexyl phosphite, diphenyl nonyl phenyl phosphite, trinonyl phenyl phosphite, 9,10 dihydro-9-
Oxa 10-phosphaphenanthrene 10-oxide,
monophosphites having a molecular weight of 200 to 1000, such as o-cyclohexylphenyl phosphite, trilauryl trithiophosphite, trioctadecyl phosphite;
Diisodecylpentaerythritol diphosphite, distearylpentaerythritol diphosphite, dinonylphenylpentaerythritol diphosphite, tetraphenyldipropylene glycol diphosphite,
4,4'isobutylidenebis- (3-methyl-6-te
rt-butylphenyl-ditridecyl phosphite),
Bisphosphite having a molecular weight of 450 to 1500, such as 4,4'isopropylidenediphenyltetraalkyl phosphite; 1,1,3 tris [(2-methyl-4 ditridecyl phosphite-5-tert-butyl) phenyl]
Butane, tetraphenyltetratridecylpentaerythritol tetraphosphite, poly (dipropylene glycol) phenyl phosphite, bisphenol A pentaerythritol phosphite, hydrogenated bisphenol A
Examples include polyphosphites having a molecular weight of 1200 or more, such as phosphite resin. Examples of the polycarboxylic acids include phthalic acid, trimellitic acid, maleic acid, fumaric acid, adipic acid, polyacrylic acid, (meth) acrylic acid- (meth) acrylate copolymer, ethylene-
Examples thereof include polycarboxylic acids having a valence of 2 or more (preferably 2 to 100) and a weight average molecular weight of 10,000 or less, such as a (meth) acrylic acid copolymer. Of these compounds, phosphites are preferred.

The hot-melt resin (B) constituting the resin composition for cleaning a molding machine of the present invention is not particularly limited.
The weight average molecular weight is 15,000 or more, and when the resin composition of the present invention is used, the softening point falls within the range described below. For example, polyolefin [polyethylene resin [polyethylene, ethylene-α-olefin copolymer] ,
Ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene (meth) acrylate copolymer, etc.], polypropylene resin (polypropylene, propylene-α-olefin copolymer, etc.)], styrene resin (Polystyrene, AS resin, ABS resin, styrene-butadiene resin, styrene-maleic anhydride resin,
Styrene-acrylate resin, HIPS, etc.),
Polyamide resin (6 nylon, 66 nylon, 11 nylon, 12 nylon, etc.), (meth) acrylic resin,
Thermoplastic polyester resin (polyethylene terephthalate, polybutylene terephthalate, polycarbonate, etc.), thermoplastic polyurethane resin, polyoxyalkylene (carbon number of alkylene group: 1 to 4) resin, polyacetal resin, polyvinyl chloride, polyvinylidene chloride,
Elastomers (ethylene-propylene rubber, EPD
M, butadiene rubber, polyester elastomer, etc.). Of these, polyolefins and styrene resins are preferred, and polyolefins are particularly preferred.

[0008] (A) and (B) in the resin composition for cleaning a molding machine of the present invention are usually 3 to 70: 9 based on the mass ratio.
7 to 30, preferably 5 to 50:95 to 50, more preferably 5 to 25:95 to 75. If the mass ratio of (A) is less than 3, the effect of forming a chelate with a metal chloride may not be sufficient, and if it exceeds 70, the cleaning effect may be insufficient.

[0009] In addition to (A), other resins may be added in an amount of 20% by mass or less based on the total mass of (A) and (B), as long as the chelate-forming properties of (A) and the metal chloride are not impaired. Agents can be added. Examples of the additives include phthalate plasticizers, phosphate plasticizers, adipic plasticizers, sebacate plasticizers, glycolate plasticizers, polyester plasticizers, and epoxy plasticizers. Stabilizers such as laurate-based organotin stabilizer, maleate-based organotin stabilizer, mercaptide-based organotin stabilizer; calcium carbonate, talc, clay, silicate, silicate, asbestos, mica, glass fiber, Fillers such as glass balloons, carbon fibers, metal fibers, ceramic whiskers, titanium whiskers; phenolic antioxidants, amine antioxidants, sulfur antioxidants, hydrazine antioxidants, amide antioxidants, etc. Antioxidants; lower aliphatic hydrocarbons, chlorinated aliphatic hydrocarbons, fluorinated aliphatic hydrocarbons (alternative Aliphatic hydrocarbons having a boiling point of 110 ° C. or lower, sodium bicarbonate, ammonium bicarbonate, sodium borohydride, azo foaming agents, nitroso foaming agents, hydrazide foaming agents, trihydrazinotriazine, water Foaming agents such as;
Flame retardants such as brominated flame retardants, antimony trioxide, magnesium hydroxide, borates, zinc borate, barium metaborate, aluminum hydroxide, red phosphorus, magnesium hydroxide, ammonium polyphosphate, tetrabromobisphenol A; Cationic activators such as quaternary ammonium salts and amine salts, anionic activators such as sulfonates, sulfates and phosphates, alkylene oxide additions (polyoxyalkylene alkyl ethers,
Nonionic activators such as polyoxyalkylene higher fatty acid esters), polyhydric alcohol type (polyhydric alcohol fatty acid esters, polyhydric alcohol alkyl ethers, etc.), amphoteric activators such as betaine type and amino acid type, polymer type antistatic agents Antistatic agents such as paraffins, microwaxes, synthetic waxes, fluorocarbons, higher fatty acids, oxyfatty acids, fatty acid amides, alkylenebisfatty acid amides, fatty acid esters, fatty alcohols, polyhydric alcohols, lubricants and mold release agents such as metal soaps Pigments such as titanium oxide, red iron oxide, graphite, cadmium pigment, ultramarine blue, azo pigment, phthalocyanine pigment, vat dye pigment, quinacridone pigment, dioxazine pigment, and dye lake pigment; anthraquinone dye, indigoid Dyes, azo dyes, etc. Postal class; nucleating agent such as dibenzylidene sorbitol; light stabilizers like; benzotriazole, include ultraviolet absorbers and the like, such as salicylate.

Of these, foaming agents, antistatic agents, lubricants / release agents, etc. are preferred, and water is added in an amount of 0.5 to 15% by mass based on the total mass of (A) and (B). When added, (A) and the metal chloride may form a stronger chelate, which is particularly preferred. In addition, an anionic activator (particularly, an alkyl (C 8 to C 20) benzenesulfonate and / or an alkane (carbon Number: 8 to 20) Sulfonate etc.] to the total mass of (A) and (B).
The addition of 5 to 15% by mass is particularly preferable because the cleaning effect of the molding machine is further increased.

The resin composition for cleaning a molding machine of the present invention has a softening point of 70 to 200 ° C., and can be washed by heating to make it into a molten state and passing through the inside of the molding machine.
As a washing method, for example, there is a method in which a resin is charged from a resin inlet of a molding machine and passed through the molding machine in the same manner as the molding resin. At this time, it is preferable that the resin which has been subjected to the molding is left in the molding machine as little as possible. Further, the resin composition for cleaning a molding machine of the present invention may be used by blending with a resin that has been molded.

The temperature at which the inside of the molding machine is washed is not particularly limited, but it is necessary to melt both the resin which has been molded and the resin composition for washing the molding machine of the present invention. ° C, preferably 150 to 250 ° C. If the temperature is lower than 100 ° C., there is a high probability that an unmelted substance is present, and effective cleaning is difficult. If the temperature is higher than 280 ° C., the resin is severely decomposed and oxidized, and the molding machine may be soiled. The pressure at the time of washing may be within the range of the pressure resistance of the molding machine, and is usually from 1 atm to 200 atm. Less than 1 atmosphere or 2
If the pressure exceeds 00 atm, the cleaning effect is not affected, but it is not economical.

The molding machine suitable for the cleaning method of the present invention is an injection molding machine for molding various industrial parts and daily necessities; an extruder for molding films, sheets, boards and pellets. Furthermore, it is not limited to these molding machines,
It is also effective for a molding machine having a structure in which a screw or a blade and a cylinder are combined.

The resin to be cleaned suitable for the cleaning method of the present invention includes:
It is a thermoplastic resin containing a halogen compound. Among these, a resin synthesized using a compound containing a halogen in at least one of a catalyst, a cocatalyst, and a solvent is preferable.
For example, resins (polyolefins) synthesized using titanium chloride, aluminum chloride, zinc chloride, organic hafnium dichloride and the like as catalysts; resins synthesized using magnesium chloride, tin chloride and the like as cocatalysts (polyolefins, styrene-based resins, polyurethane And the like; resins synthesized using chloroform, methylene chloride, ethylene dichloride, and the like as a solvent (styrene-based resins, polycarbonates, and the like). Of these, polyolefins synthesized with a Ziegler-Natta catalyst system, a metallocene catalyst system, etc. are particularly preferred. These polyolefins contain metal chlorides such as calcium chloride and magnesium chloride as a result of adding a neutralizing agent to neutralize hydrochloric acid gas generated from chlorine contained in the Ziegler-Natta catalyst system and the like. Efficient removal of these metal chlorides is effective in preventing resin coloring. Also, once chlorine in the resin is converted into a stable metal chloride, it is also effective to remove the same in a similar manner to prevent resin coloring. Stable metal chlorides include lithium chloride, potassium chloride, sodium chloride, calcium chloride, magnesium chloride, barium chloride, lead chloride and the like. By forming these stable metal chlorides, coloring of the resin is suppressed, and chlorine is efficiently removed from the molding machine by forming a strong chelate with (A).

[0015]

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

Example 1 Polypropylene (J309G made by Grand Polymer) 10
0 parts, 10 parts of distearylpentaerythritol diphosphite and 5 parts of calcium stearate are dry-blended and mixed with a twin-screw extruder (TEM35B manufactured by Toshiba Machine Co., Ltd.) for 210.
It kneaded at ° C and produced resin composition pellet (X1).

Example 2 Polypropylene (J309G made by Grand Polymer) 10
0 parts and 10 parts of triphenyl phosphite were dry-blended and mixed with a twin-screw extruder (TEM35B manufactured by Toshiba Machine Co., Ltd.) for 210 parts.
It kneaded at ° C and produced resin composition pellets (X2).

Example 3 An aqueous solution (40%) of polyacrylic acid (weight average molecular weight 5000) was produced from polypropylene (J309G made by Grand Polymer) from a hopper of a twin-screw extruder (TEM35B made by Toshiba Machine) equipped with a liquid feeder and a vent. Each was fed from a liquid feeder, kneaded at 210 ° C. with a mixing ratio of polypropylene and polyacrylic acid aqueous solution of 4: 1, and water was removed from the vent to prepare resin composition pellets (X3). (X3) is polypropylene 89
Parts, polyacrylic acid 11 parts and water 0.9 part.

Example 4 Polypropylene (G309 manufactured by Grand Polymer) 10
0 parts, 10 parts of distearylpentaerythritol diphosphite, 10 parts of an anionic antistatic agent (Chemistat 3033, manufactured by Sanyo Chemical Industries) and 5 parts of calcium stearate are dry-blended and twin-screw extruder (TEM35 manufactured by Toshiba Machine Co., Ltd.)
B) Kneading at 210 ° C and resin composition pellets (X4)
Was prepared.

Examples 5 to 9 and Comparative Example 1 1 kg of polypropylene (MA3H manufactured by Nippon Polychem) at 240 ° C. using a twin screw extruder (2D25S manufactured by Toyo Seiki)
/ Hr, and air was blown at 30 ml / min from the feed port and the vent port. The extruder was washed with the resin composition (X1 to X4) at intervals shown in Table 1, and the degree of coloring of the polypropylene was evaluated. The results are shown in Table 1.

[0021]

[Table 1] * 1 Time from the start of the test when the color number (Hazen) of the molten polypropylene at the extruder outlet reaches 120 (hr)

[0022]

The resin composition of the present invention is excellent in heat resistance and has an effect of improving the heat resistance of a molding resin, so that it is extremely useful as a detergent for a molding machine.

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Claims (8)

[Claims] 1. A resin composition for cleaning a thermoplastic resin molding machine, comprising a compound (A) which forms a chelate with a metal chloride and a hot melt resin (B). (A): (B) is 3 to 3 based on the mass ratio.
The resin composition for cleaning a molding machine according to claim 1, wherein the ratio is 70:97 to 30. 3. The resin composition for cleaning a molding machine according to claim 1, wherein (A) comprises at least one compound selected from phosphorous acids, phosphites and polycarboxylic acids. 4. The resin composition for cleaning a molding machine according to claim 1, wherein (B) comprises a polyolefin. 5. The resin composition for cleaning a molding machine according to claim 1, further comprising water and / or an anionic activator. 6. A method for cleaning a thermoplastic resin molding machine, comprising passing the resin composition for cleaning a molding machine according to claim 1 in a molten state through a molding machine (L). 7. A molding machine for molding a resin containing (L) at least one metal chloride selected from lithium chloride, potassium chloride, sodium chloride, calcium chloride, magnesium chloride, barium chloride and lead chloride. 7. The cleaning method according to claim 6, wherein: 8. The cleaning method according to claim 6, wherein (L) is a molding machine for molding a resin synthesized by using a compound containing a halogen as at least one of a catalyst, a cocatalyst, and a solvent. .