JPS6038403B2 - Dispersion manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a dispersion of a modified polyolefin.

Since polyolefins such as polyethylene and polypropylene are typical non-polar substances, it is known that their adhesion to metals and other films is extremely low.

Various proposals have been made to improve the adhesion of secondary polyolefins.For example, chemical treatments such as the '1-sulfate chromate method are effective if heated, but
Because it is a green method, workability is poor, and the use of acid causes corrosion to the reactor and other parts. Therefore, this method is one that is only rarely implemented today for basic research or for comparison with other surface treatment methods. Industrially, '21 is a chemical treatment in which an unsaturated carboxylic acid is grafted onto a polyolefin, and further subdivided into 'a) A polyolefin is heated and dissolved in a hydrocarbon solvent, and an unsaturated carboxylic acid is grafted in the presence of a radical catalyst. method, {b)
A method in which a finely ground polyolefin is charged in water containing a surfactant, made into a suspended state, and an unsaturated carboxylic acid is grafted in the presence of a radical catalyst; A method in which the surface of '3' polyolefin is oxidized with air, oxygen or ozone to create polar groups, '41 city gas or flame treatment in which polyethylene is brought into direct contact with a hydrocarbon gas flame, [discharge treatment by 5' corona discharge, ■ surface graft treatment in which polar substances are grafted onto the polyolefin surface to improve adhesion,
Further subdivision: [a] Machi Co is used as the radiation source, and methyl methacrylate is used as the monomer to be grafted.
Grafting method using radiation using acrylamide, acrylic acid, methacrylic glycidyl ether, methylol acrylamide, methyl acrylate, vinyl acetate, etc.
and 'b' A method of grafting methyl methacrylate and maleic acid onto a polyolefin using a radical catalyst, '7' A heat treatment in which polyethylene powder or sheet is placed on the metal surface and heated to 200 to 300°C, and
[81] There is a blending process in which an inorganic filler is mixed into polyolefin. Polyolefins having good adhesive properties have been obtained by the methods described above or a combination thereof. However, these methods have the following drawbacks in the food-related field. In other words, [1
In chemical treatment 1, acid; in chemical treatment '2), unreacted unsaturated carboxylic acid, radical catalyst, surfactant, [6]
In the surface grafting process (2), unreacted monomers and radical catalysts remain in the resin, and in the blending process (2), inorganic fillers remain in the resin.
It is necessary to wash the resin, and the washing process takes a long time.
Furthermore, these residues may not be removed even after a long period of cleaning. In food-related and non-food-related fields, it has the following drawbacks. In the chemical treatment {1}, a large amount of water must be used to remove acids and the like from the resin, and wastewater treatment is necessary because the wastewater contains chromium ions. (Chemical treatment of 2' uses solvents, monomers, and radical catalysts, so there is a risk of fire and toxicity during work. Also, the method of using a surfactant of ■-[b} Adhesion may not be sufficiently improved due to the presence of the agent. Treatments '3', [4l and '5-] may not provide sufficient adhesion. {6} Surface grafting treatment with radiation The irradiation equipment is expensive and dangerous.The applicant of this patent has already developed an inner coating composition for can manufacturing, which is characterized by dispersing a polyolefin into which a polar group has been introduced in a solid state in a solvent. Patent applications (Samurai Kao No. 50-138694, etc.) have been filed.

Furthermore, as a result of research on polyolefin paints that do not cause food hygiene problems due to residual monomers and have excellent adhesion to metals, etc., the present invention developed an untreated polyolefin paint that does not have any polar groups introduced into it, using a hydrocarbon solvent. A modified polyolefin dispersion in which the polyolefin is modified by irradiating ultraviolet rays to a suspension dispersed in a solid state in one or more of the following or a mixed solvent of a hydrocarbon solvent and a non-hydrocarbon solvent. This was done based on the knowledge that it has excellent workability and adhesion, and poses no food hygiene problems. The modified polyolefin dispersion according to the present invention can be used as is) in internal coating compositions for rice bran, anchor coating agents,
In addition to being able to be applied as other paints or adhesives, the modified polyolefin is separated from the solvent by a conventional spray drying method, and the resulting finely powdered modified polyolefin is used as powder coating, hot melt material, etc. It can be applied to other things.

The polyolefin used in the present invention is not particularly limited, but desirably, when used in food-related fields, a polyolefin containing no additives such as antioxidants is appropriately selected.

When modified polyolefins containing additives are used in food-related fields, the additives may migrate into the food. In the present invention, the temperature range during horizontal irradiation of ultraviolet rays is preferably a temperature at which a suspended state is maintained, rather than room temperature.

At a temperature higher than the temperature at which the suspended state is maintained, the viscosity increases due to the solution state, making it difficult to form the solution. The hydrocarbon solvent and non-hydrocarbon organic solvent in the present invention are not particularly limited, but the solvent may be appropriately selected depending on the intended use.

Solvents used in the present invention include hydrocarbon solvents with relatively low boiling points such as benzene, hexane, heptane, and mineral spit, aromatic hydrocarbons such as toluene and xylene, isooctane, nonane, and decane. There is no problem depending on the use, even if it is an aliphatic hydrocarbon such as methylcyclohexane, ethylcyclohexane, alicyclic hydrocarbon such as decahydronafuritane, or a relatively high boiling point hydrocarbon such as solvent naphtha.

Other solvents that can be used with the above hydrocarbons include ethanol, methanol, propanol, isopro/
Alcohol solvents such as gunol, butyl alcohol, octanol, cetyl alcohol, diacetone alcohol, ester solvents such as ethyl acetate, butyl acetate, cellosolve acetate, methyl ethyl ketone, methyl lysoptyl ketone, hexanone , ketone solvents such as isophorone, ethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, etc. Examples include ether solvents, carbon tetrachloride, halogenated hydrocarbon solvents such as trichlorethylene, and the like.

If a hydrocarbon solvent, especially a hydrocarbon solvent with a boiling point higher than the melting point of the polar group-containing polyolefin is used alone, the system may clog in the gun during spraying, making it difficult to coat.

In addition, when using only non-hydrocarbon solvents, a whitening phenomenon due to resin precipitation is observed immediately after painting or in the early stage of phosphorization due to resin precipitation before the resin particles harden. Since it cannot form a coating film, it is not suitable for use as an inner surface paint for cherry blossoms. The ratio with hydrocarbon solvent is approximately 5/95 to 95/
5 (weight), preferably from about 30/70 to 70/30, depending on the solvent and the type of polar group-containing polyolefin. In carrying out the present invention, the weight ratio of polyolefin and solvent is 1/100 to 30/10.
The degree of temperature of the polyolefin is preferably 5/100 to 20/10 degrees Fahrenheit, and the degree of temperature of the polyolefin is less than 100 degrees Fahrenheit, preferably 5 to 2 degrees Fahrenheit.
It is about 0.

The method of irradiating ultraviolet rays is not particularly limited, but for example, a part of the side surface of the reactor may be made of quartz glass and ultraviolet rays may be irradiated from the side, or a portion of the upper part of the reactor may be made of quartz and ultraviolet rays may be irradiated from the top. The adhesiveness of modified polyolefin has a correlation with the amount of ultraviolet irradiation, and when the amount of ultraviolet irradiation is large, the irradiation time and the distance from the surface of the suspension solution should be selected appropriately. Further, the irradiation atmosphere is not particularly limited, and may be air, oxygen, or nitrogen. Polyolefins modified according to the invention exhibit good adhesion to metals such as tinplate and aluminum, polyolefins, and plastics such as epoxy resins. Moreover, it is manufactured based on polyolefin, and its general properties such as processability, strength characteristics, and chemical resistance completely retain the properties of the base polyolefin. Furthermore, since no components other than polyolefin and solvent are used, there is no toxicity after the solvent evaporates, and it is safe from a food hygiene perspective. Further, the volatilized solvent can be recovered and reused. Hereinafter, the present invention will be specifically explained with reference to Examples.

Example "Central part" refers to parts by weight. Example 1 Low-density polyethylene (F-22 manufactured by Asahi Dow) was added to the dripping tank.
70, Melt index 7, Softening point approximately 110℃) 1) Add 4 parts of xylene and heat to 85°C while stirring.
It dissolves completely when heated to

A reaction vessel with a quartz glass on the top was charged with 5 ml of cold xylene, and the solution was added dropwise while stirring to obtain a milky white dispersion with an average particle size of 5 ml. Five anchorages of isopropanol are added to this, and while irradiation is carried out through the upper quartz glass using a Fox W ultraviolet lamp, retaining is carried out.
Since the distance between the liquid level and the lamp was 20, irradiation was performed for 1q hours. The obtained dispersion is stable not only at the prepared diameter but also after aging for 3 months, and does not clog the gun during coating. The above dispersion was applied to a tin plate coated with an epoxy phenolic base coat at a ratio of 70 c/base using an air spray gun and phosphorized at 160 oo for 5 minutes.

Visual inspection showed that the smoothness of this coated object was good, and the adhesion was excellent using the Goban eye test, and the bending resistance was measured by applying an impact to the coated plate with the coating outside at 5°C. Even though it was bent heavily, no cracks were observed in the paint film.
As for the boiling resistance of the painted objects by immersing them in water for 30 minutes, no whitening or blistering was observed in the painted objects, and the adhesion after boiling was 100/100 according to the cross-cut test method. It was found to be of sufficient practical use. Comparative Example 1 Adhesion was tested in the same manner as in Example 1 except that no ultraviolet irradiation was performed, and no practical strength was shown.

Example 2 Low-density polyethylene (Mitsui Polychemical ■
Manufactured by Mirason 68, Melt Index 2 Softening point approx. 1
Add 1 part of 100C) and 4 parts of ethylcyclohexane and heat to 9000C while stirring to completely dissolve.

50 parts of cold ethylcyclohexane was placed in a reaction vessel with quartz glass on the top, and the above solution was added dropwise while stirring to obtain a milky white dispersion with an average particle size of 15 mm. to this,
5. Add methyl lysobutyl ketone while stirring to form a suspension. Use a pine W ultraviolet lamp to irradiate the quartz glass at the top while doing rope azusa. This dispersion is stable not only immediately after preparation but also after three months of aging, and does not clog the gun during coating. The above dispersion was applied to the inner surface of the molded aluminum cake using an air spray gun.
It was applied at an o/ground ratio of 0 and baked for 5 minutes at 160 qo. The smoothness of this coated product was good as a result of visual inspection, and the adhesion, bending resistance, cold resistance at 5° C., and boiling resistance according to the cross-cut test method were sufficient for practical use. Example 3 A modified polyolefin produced in Example 1 using toluene instead of xylene and methyl ethyl ketone instead of isopropanol was spray-dried to obtain a fine powder.

Apply electrostatic coating to an aluminum plate heated to 160°C to a film thickness of 30 mm.

Adhesion according to the cross-cut test method is 100/100,
The bending resistance and boiling resistance for 30 minutes were good. Example 4 Dripping tank polypropylene (Mitsui Polychemical F
Add 1 anchor of Ikari Q (melt index 90, softening point 145) and 9 anchor of Solvesso 150 (petroleum-based solvent, manufactured by Shell Chemical, trade name) and heat to 120 oo while stirring to completely dissolve.

A reaction vessel with a quartz glass on the top was charged with cellosolve acetate having 5 squares, and the above solution was added dropwise while stirring to obtain a milky white dispersion with an average particle size of 6A. Using a Fox W ultraviolet lamp, perform fly azusa while irradiating the quartz glass above. The distance between the liquid surface and the lamp was set at 20 meters, and irradiation was performed for 10 hours in an air atmosphere. This dispersion was uniformly applied to an aluminum slope at a ratio of 80 o/100 using a roll coater, and was soaked at 200°C for 5 minutes. As a result of the durability test of the obtained coated product, the smoothness was good as a result of visual inspection, the adhesion was 100/100 by the goblin test, and the bending resistance and retort resistance were good. It was sufficiently usable as a retort food. Example 5 The paint obtained by mixing the base of the dispersion 2 produced in Example 1 and the base of the epoxy-phenol paint 8 was coated on a tin plate using a roll coater at a ratio of 70 parts per 100 parts. It was applied evenly to the surface and left at 180 qo for 5 minutes.

Claims (1)

[Claims] 1. Polyolefin is treated with one or two hydrocarbon solvents.
A modified polyolefin dispersion characterized in that the polyolefin is modified by irradiating ultraviolet rays to a suspension dispersed in a solid state in a mixed solvent of a hydrocarbon solvent and a non-hydrocarbon organic solvent. How the body is manufactured.