KR102070240B1 - A method of coating expandable graphite on expandable polystyrene resin particles and a method of coating the expanded resin particles - Google Patents

Abstract

The present invention oxidizes the surface of expandable polystyrene (EPS) resin particles with ozone to modify the hydrophobic EPS particles to hydrophilic, and then the modified EPS at 1 to 30 rpm in the presence of a polar organic solvent for 1 to 5 minutes. The present invention relates to a method for producing expandable polystyrene resin particles coated with expanded graphite in which expanded graphite is added to the solvent and coated with paraffin while stirring.

Description

A method of coating expandable graphite on expandable polystyrene resin particles and a method of coating the expanded resin particles}

The present invention is to obtain an expandable polystyrene (hereinafter referred to as 'EPS') resin particles by coating the expanded graphite to ensure incombustibility, the expansion ratio (Expansion rato) is 20ml / g-500ml / g, the particle size A method of coating expanded graphite to expandable polystyrene resin particles to secure non-combustibility by adhesively coating expanded graphite having 20mesh-300mesh to EPS particles having a diameter of 0.2mm to 1.5mm, and a coated hydrophobic (hydrophobicity) EPS resin. The surface layer of the particles is oxidized so that the EPS surface layer has a hydrophilic property so as to obtain expandable polystyrene resin particles coated with expanded graphite in which expanded graphite is easily coated on EPS, and a non-combustible molded article using the particles.

More specifically, paraffin chloride and expanded graphite are injected into the modified EPS particles by oxidizing the surface layer with ozonized air and the modified EPS particles are sprayed with a polar organic solvent and sprayed with a polar organic solvent. The adhesive coating is on the EPS particles with stirring for 1-5 minutes at 30 rpm.

In the above expanded graphite, the expansion ratio to block combustion is 20ml / g-500 ml / g, it is preferable to have a physical property of the particle size diameter 20mesh-300mesh.

Expandable polystyrene (EPS) is a polymer of styrene which is a raw material of styrofoam and is spherical resin particles having a diameter of about 0.2 mm to 1.5 mm. A foaming gas is contained inside the particles, and the foamed gas is heated to a predetermined temperature to foam the particles 80 times or more, and the foamed particles are aged, and a molded article formed by steam is usually called styrofoam.

In recent years, various types of efforts have been made to improve non-combustibility, and styrofoam insulation materials having high incombustibility are required. In the styrene polymerization process and extrusion process, non-combustible materials are dispersed inside the resin particles or EPS particles are heated by steam. By foaming and coating the flame-retardant or flame-retardant material on the foam particles there are manufacturing methods.

Korean Patent No. 1300627 of the present inventors discloses a technique for producing expanded polystyrene resin particles having excellent thermal insulation property by coating a foamed polystyrene resin particle with a low-temperature plasma by discharging the insulating material, a flame retardant material, and a functional material on the surface layer of the modified foam resin particle. Korean Patent No. 1448051 discloses a method of forming caramel by mixing and reacting sugar and phosphoric acid, preparing an adhesive mixed with expanded graphite and a dispersant isocyanate, and foaming EPS particles and applying the molded styrofoam.

Korea Patent Publication No. 10-2016-0134452 discloses a non-flammable coating film coating agent and a manufacturing method and use thereof in which expanded graphite expanded to a volume of about 500 times due to expansion due to expansion, and expanded graphite is added to the coating agent. A method is disclosed.

Korean Patent Laid-Open Publication No. 10-2011-0065707 Disclosed is a method for producing a flame-retardant expandable polystyrene resin particles characterized in that it comprises a silicon-based powder and expanded vermiculite powder in a styrene-based polymer.

Such conventional prior arts are techniques for coating and forming the intended functional materials by foaming EPS particles 80--100 times. For example, when foaming 80-fold EPS, low density styrene foam particles have a cross-sectional area of 80 times. Because of the technology of coating and molding functional materials using an adhesive, there is a problem that the manufacturing process of coating is uneconomical and the final properties are not uniform and fall short of the relevant legal regulations.

The present invention solves the problems of the prior art as described above by injecting ozonized air into the polymerized EPS particles to oxidize and modify the surface layer and expand the expanded graphite powder into EPS particles in the presence of a polar organic solvent. In the adhesive coating step, the expanded graphite coated resin particles are obtained and foamed to produce a non-combustible heat insulating material.

1. Korean Patent No. 1300627 1. Korean Patent No.1494801 1. Republic of Korea Patent Publication No. 10-2016-0134452 1. Republic of Korea Patent Publication No. 10-2011-0065707

It is an object of the present invention to oxidize hydrophobic EPS particles with ozonated air to modify them hydrophilically to improve coating properties and to adhesively coat expanded graphite with EPS particles.

It is another object of the present invention to obtain expanded graphite coated EPS particles in which expanded graphite is adhesively coated onto EPS particles without breakage of particles by using paraffin, a phase change (PCM) material, as a medium in the presence of a polar organic solvent. have.

It is still another object of the present invention to obtain a product having improved physical properties by foam-molding EPS coated with expanded graphite and applying expanded graphite to a molded surface layer.

Expandable Polystyrene (EPS) resin particles used in the present invention are generally based on styrene homopolymers or copolymers, and contain butane or pentane gas as a blowing agent.

Since the EPS particles are hydrophobic, they have a property of repelling the adhesive coating of hydrophilic expanded graphite, and thus, the present invention facilitates adhesive coating with expanded graphite by modifying the particle surface layer to hydrophilicity by exposing the EPS particles to ozone.

The ozone is a material in which oxygen molecules (O ₂ ) are decomposed to combine three oxygen atoms, and three oxygen atoms are present in the form of four resonance structures.

Ozone has the strongest oxidizing power after fluorine and its reactivity with organic matter is due to its oxidizing power. Ozone is usually generated by applying physical and chemical energy to oxygen and changing it to ozone. The ozone can be generated from a silent discharge method, an electrolytic method, a photochemical method, or a radiation method.

In general, the silent discharge method is most widely used. The silent discharge method inserts a dielectric such as glass or ceramic between a pair of electrodes, blows air or oxygen, and applies 6kv to 18kv AC high pressure to the electrode to generate ozone in the discharge region. do. The ozone generation of silent discharge method can obtain ozone of 10g ~ 35g / m3 when using air and 50g ~ 150g / m3 when using oxygen, and the power consumption is 10 when injecting oxygen at water-cooled cooling water temperature of 25 ℃. ~ 13 kwh / kg-O ₃ and 15-20 kwh / kg-O ₃ when injecting air. The ozone generating apparatus is broadly classified into a circular coaxial cylindrical shape and a plate-like flat plate type. In the present invention, the coaxial cylindrical electrode structure of the silent discharge method widely used in the industry is used.

Ozone is generated by the following reaction

^{_{O 2 + e - -> O}} + O + e -

O ₂ + e ^-- > O ₂ ⁺

O + O ₂ + M-> O ₃ + M

O ₂ + O _2- > O ₃ + O

[Ozone Generator and EPS Ozone Treatment System of the Present Invention]

Expanded graphite is chemically treated with natural flake graphite with acidic material to infiltrate acidic compound between layers of graphite and is dried. When it is heated above 150 ℃, it can decompose and generate gas and expand to 20 ~ 500 times of volume. It is commonly referred to as expandable graphite.

Expanded graphite expands by heating, and the foam layer blocks the heat source, so it can be selected from expanded graphite having an expansion rate of 20 ml / g-500 ml / g. The preferred expansion rate is 100 ml / g-300 ml. / g and the particle size is 20mesh-300mesh. Expanded graphite is unable to achieve the object of the present invention because the expanded physical properties are lost when the particles are damaged by high pressure or impact.

The present invention may adhesively coat 1 to 50 parts by weight of expanded graphite with respect to 100 parts by weight of EPS particles, preferably 10 to 25 parts by weight of adhesive coating. If this range is exceeded, there is a slight increase in physical properties and economical efficiency. Therefore, expanded carbon of 92% (Carbon Content), Expansion rate 200ml / g to 500ml / g, Particle distribution 80 mesh or more is used. It is desirable to.

Paraffin used in the present invention is a solid hydrocarbon mixture and is a substance that is soluble in ether or benzene ester and has excellent lubricity and adsorption property. Dissolved in polar organic solvent and permeate coated on the EPS particle surface layer in the step of joint coating the expanded graphite to EPS. The paraffin is selected from paraffin chloride, solid paraffin, and liquid paraffin, and used alone or in mixture of two or more, 1 to 30 parts by weight, preferably 5 to 15 parts by weight.

Polar organic solvents act as solvents for the adhesive coating of EPS with paraffins and expanded graphite.

For example, dimethylformamide, dimethylacetamide, acetic acid, ethanol, acetone, methanol, ethylacetate, one of these alone Or by mixing two or more kinds, using 0.1 to 15 parts by weight, preferably 1 to 5 parts by weight.

The production process of oxidatively modifying expandable polystyrene resin particles with ozonated air and coating expanded graphite is as follows.

1. The step of preparing effervescent polystyrene (EPS) resin particles quantitatively discharged through the ESP storage into a closed cylindrical tumbler mixer and stirring at 1 to 30 rpm.

2. Blow dry air through a device consisting of a compressor (pressure 3-4Kgf / cm ² ) and After cooler Air Filter freeze-drying device between the electrodes of an ozone generator with a ceramic dielectric sandwiched between a pair of electrodes and generate ozone. When 6kv ~ 18kv AC high pressure is applied to the device, air is passed through the discharge zone and ozonated air is injected into the blender to oxidize and modify the EPS surface in the presence of ozone.

3. Add paraffin chloride and expanded graphite to modified EPS particles, spray polar organic solvent, maintain compressive strength of 0.005MPa ~ 0.1MPa, and coat and discharge by stirring for 1-5 minutes at 1 ~ 30rpm.

4. Drying the exit coated EPS particles for 1-60 minutes at a temperature below 40 degrees.

5. Drying The adhesive resin is sprayed onto the cured resin particles, dried to a temperature of 40 degrees or less, and the dust and defective products are screened.

The mixer was operated with 0.005 MPa ~ 0.1MPa compressive strength to prevent breakage of expanded graphite and used a cylindrical, tumbler type mixer with a diameter of 1m and a length of 1.5m.

When the mixer is rotated, the coating EPS and the expanded graphite paraffin to be coated are mixed while falling vertically by gravity, polar organic solvent is injected, and adhesive coating is started.

The adhesive resin (35% solids) may be acrylic resin, olefin resin, urethane resin, polystyrene resin, vinyl acetate resin, epoxy resin, vinyl chloride resin, chloroprene rubber resin, waste glycol resin, and the like. Among them, one or two or more thereof may be mixed to spray 0.1-15 parts by weight based on the EPS weight. Preferably they are 1 weight part-5 weight parts.

On the other hand, by forming a film coated with expanded graphite mixed with an adhesive resin on the surface of the molded article foamed EPS of the present invention by a known bead method can further improve non-combustibility and thermal insulation.

0.1 to 15 parts by weight of expanded graphite may be applied to the weight of the molded article, preferably 1 to 5 parts by weight, and the adhesive resin is used as the adhesive resin, and one or two or more kinds thereof may be mixed for the weight of the molded article. 0.1-15 weight part can be mixed, Preferably it is 1 weight part-5 weight part.

The present invention has an effect of improving the coating property with hydrophilic expanded graphite by modifying the EPS surface layer with ozone to hydrophilic.

In addition, by oxidizing the surface of the hydrophobic and flammable EPS particles, the expanded graphite can be easily coated on the EPS, thereby reducing the defective rate of the product.

In addition, by using the polar organic solvent and paraffin having excellent lubricity as a solute and a solvent, the expanded graphite can be easily coated on the EPS, thereby reducing the coating time.

Hereinafter, the non-combustible properties of the styrofoam foam-molded foamed polystyrene prepared in the embodiment of the present invention, but the scope of the present invention is not limited to the scope of the embodiment can be said to include all ranges supported by the embodiment. have.

<Example 1>

First stage

After the polymerization is completed, the expandable polystyrene particles are discharged from the silo, and 200Kg is quantitatively transferred to a cylindrical mixer having a diameter of 1,000 mm and 2,000 mm in length to inject air which is ozonated and stirred to oxidize and modify the EPS particles.

2nd step

20 parts by weight of expanded graphite and 10 parts by weight of paraffin were added to 100 parts by weight of ozone-modified resin particles, and 2 parts by weight of dimethylformamide, a polar organic solvent, was sprayed and stirred at 0.005 MPa to 0.1 MPa for 5 minutes. The particles are adhesively coated with expanded graphite.

3rd step

2 parts by weight of waste phenolic resin and 1 part by weight of urethane resin were coated with respect to 100 parts by weight of the expanded graphite coated resin particles of the second step, dried with hot air of 40 degrees or less, and foamed and molded 60 times by a known bead method. (Density 18) was obtained.

<Example 2>

In the same manner as in Example 1, foaming and molding were carried out using a known bead method to obtain a styrofoam having a density of 20. 10 parts by weight of an adhesive resin containing expanded graphite was coated on the surface thereof, and nonflammability was measured.

Comparative Example 1

The EPS particles were prepared in the same manner as in Example 1, but the expanded graphite was adhesively coated on the EPS particles without oxidizing the surface of the EPS particles with ozone, and foamed and molded at 60 times by a known bead method to form styrofoam (density 18). Dust of expanded graphite was produced during foaming and molding.

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<Heat Release Test>

The heat release test of the sample of Example 1, the sample of Example 2, and the said sample which produced the foamed styrofoam with the sample of the comparative example 1 was performed. The test was conducted three times by the performance test (KS F ISO 5660-1: 2008) of the building material and structure of the building, and a 0.38 mm thick iron plate was placed on both sides of the styrofoam block manufactured in the examples and comparative examples. Measurements were made using padded specimens.

The results are shown in the following [Table 1].

Test Items Example 1 Example 2 Comparative Example 1 Criteria

Heat release experiment
Total emissions (MJ / m²) 7 5 8.5 8 or less Heat emission continuously 200
Time over kw / m² (S)
9
7
12
below 10 Full melting of heartwood, penetrating
Changes such as cracks and holes
none
none
Has part
No

As shown in [Table 1], Examples 1 and 2, but the amount of heat extraction is very low, but in the case of Comparative Example 1 was found to exceed 8MJ / m ² , and Examples 1 and 2 were There was no harmful deformation in the melting and fire prevention over the thickness, in the case of Comparative Example 1 it could be confirmed that the deformation occurs in part.

Claims (6)

a) oxidizing the expandable polystyrene particles with ozonated air to obtain modified expandable polystyrene particles;
b) 10-50 parts by weight of expanded graphite and 5-15 parts by weight of paraffin having an expansion ratio of 20 ml / g-500 ml / g and a particle size of 20 mesh-300 mesh with respect to 100 parts by weight of expandable polystyrene particles in the presence of a polar organic solvent. Coating expanded graphite particles with expanded polystyrene particles while stirring at a pressure of MPa-0.1 MPa;
c) one or a combination of two or more selected from the group consisting of urethane resin, polystyrene resin, vinyl acetate resin, vinyl chloride resin, and waste glycol resin with respect to 100 parts by weight of the expandable graphite coated expandable polystyrene particles Drying by spraying 1 to 5 parts by weight of the resin;
d) foam molding the expanded graphite coated expandable polystyrene particles;
A method for coating expanded polystyrene resin particles with expanded graphite, characterized in that consisting of. delete The method of claim 1,
The paraffin is coated with expanded polystyrene resin particles, expanded graphite, characterized in that the use of one or a mixture of two or more selected from paraffin chloride, solid paraffin and liquid paraffin. delete The method of claim 1,
The polar organic solvent is expanded graphite, which is characterized in that the use of one or a mixture of two or more of acetic acid, ethanol, acetone, ethyl acetate (Ethylacetate) to expandable polystyrene resin particles How to coat.
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