KR100988249B1 - Manufacturing method of thermoplastic powder coating material containing non-halogen hybrid flame retardant - Google Patents

Abstract

PURPOSE: A manufacturing method of a thermoplastic powder coating agent is provided to secure the excellent adhesive property with a metal object by changing non-polar polyethylene into an adhesive resin. CONSTITUTION: A manufacturing method of a thermoplastic powder coating agent comprises the following steps: reforming non-polar polyethylene, and using as main resin with a graftomer(101); compounding the graftomer, an adhesive resin composition, a phosphate-based flame retardant, and an inorganic flame retardant(102); obtaining powder by coarsely breaking the compounded mixture and pulverizing the powder under 300 microns(103,104); and adjusting the size of the compound(105).

Description

Manufacturing Method of Thermoplastic Powder Coating Material Containing Non-Halogen Hybrid Flame Retardant {Manufacturing Method of Thermoplastic powder coating material containing non-halogen hybrid flame retardant}

The present invention relates to a method for producing a thermoplastic powder coating agent containing a non-halogen hybrid flame retardant, comprising a mixture of organophosphorus and inorganic flame retardants for imparting flame retardancy to an adhesive resin-grafted graft polymer and an adhesive resin. The present invention relates to a method of finely powdering through a mechanical grinding method after producing the pellet in a pellet state.

The present invention relates to a method for producing a thermoplastic powder coating containing a non-halogen hybrid flame retardant to form a coating film on the metal coating to act as a finishing material, and more particularly, in a hot melt powder coating agent comprising a polyethylene resin as a main component, Modified polyethylene composed of 20 to 40% by weight of graft monomers with adhesive functional groups and 30 to 70% by weight of adhesive resins is used as the main resin, and the non-halogen hybrid flame retardant is composed of organophosphorus flame retardants and inorganic flame retardants. It relates to a powder coating composition containing a non-halogen hybrid flame retardant, characterized in that 5 to 30% by weight of a mixture (hereinafter, flame retardant composition), and a method for producing the same.

In general, the coating of metal parts is a coating process to apply paint, varnish, lacquer, etc. to protect metal parts from oxidation, and to increase durability and aesthetic effect. Conventional liquid paints are a mixture of polymer resins, binders, and pigments in volatile organic solvents. After coating, the coating film is formed by volatilization of organic solvents. Most of the organic solvents used are hazardous substances of VOC. There is a problem that affects directly or indirectly.

Powder coating, which is the most ideal metal finishing material from the point of view of VOC, is a 100% solid paint that does not contain any diluent such as organic solvents or water, and arrives on the coating (mainly metal), and is heated, melted, and coated. It is a way of forming.

On the other hand, the conventional thermoplastic powder coating agent is a powder coating agent mainly made of non-polar polyolefin, such as polyethylene, polypropylene, ethylene vinyl acetate, etc. The main coating properties are excellent coating initial physical properties but not coated with a metal surface coated coating If a part of is broken, there is a problem that the lifting phenomenon is easily spread to the entire coating film and the durability is insufficient.

In addition, the conventional thermoplastic powder coating agent is a trend that the application process is simple and excellent surface properties are increasingly used, but as most plastics are combustible materials, there is a problem in that fire safety, that is, lack of flame retardancy in this respect, When an excessive amount of flame retardant is added for improvement thereof, powder production is not easy and there is a difficulty in accompanying a non-uniform coating surface.

Halogen-based flame retardants (bromine-based, combustion-based), heavy metal compounds (antimony-based) and halogen-heavy metal composite flame retardants have been used to meet the above requirements, while halogen-based flame retardants have excellent flame retardance even when used in small amounts. When burned, toxic compounds such as HCl and HBr are generated, and under anoxic conditions, there is a problem in that life, property and environmental damages are generated by generating halogenated dioxins, furans, etc., which are highly toxic carcinogens.

Non-halogen flame retardants include inorganic flame retardants such as aluminum hydroxide, magnesium hydroxide, zinc stannate, guanine-based, molybdate and zirconium. Among these, aluminum hydroxide and magnesium hydroxide, which are commonly used, are inexpensive and dehydrated. Due to the heat-absorbing properties, the flame retardancy is expressed, but in order to obtain sufficient flame retardancy, an excessive amount of 60% by weight or more is usually used, which causes a problem in the mixing process and deteriorates the quality of the product.

Examples of the organophosphorus flame retardant include ammonium posphate, ammonium polyphosphate, melamine phosphate, and organophosphate esters. Phosphorus flame retardant is obtained by pyrolysis of phosphoric acid → metaphosphate → polymetaphosphate protective layer and polymetaphosphate. Although the carbonized film produced by the dehydration has a blocking effect, it exhibits excellent flame retardancy, but there is a cost burden when used alone.

Accordingly, the present invention is to solve the above problems, by improving the non-polar polyethylene with an adhesive resin, excellent adhesion to metal coatings, by using an appropriate amount of non-halogen flame retardant mixture to ensure flame retardancy and uniform coating properties An object of the present invention is to provide a method for preparing a hot melt powder coating composition.

According to another aspect of the present invention, in the preparation of the powder coating agent, after the homogeneous mixing of the graft copolymer, the adhesive resin and the flame retardant composition in a twin-screw extruder to produce a pellet of a predetermined size, 500 ~ through mechanical grinding method It is an object of the present invention to provide a method for producing a powder coating composition, comprising the steps of coarsely pulverizing to a size of 1,000 μm, followed by fine grinding to 300 μm or less, and finally adjusting the particle size to have a size of 100 to 250 μm. have.

As can be seen from the above, the thermoplastic powder coating agent containing the non-halogen hybrid flame retardant prepared according to the present invention has excellent adhesion to the coating and excellent flame retardancy.

The present invention is designed to improve the problems of the prior art as shown above, in the method for producing a thermoplastic powder coating comprising a non-halogen hybrid flame retardant, in order to impart adhesion to the powder coating agent maleic hydride The present invention relates to a thermoplastic powder coating comprising using modified polyethylene and using an organophosphorus-inorganic hybrid halide flame retardant to impart flame retardancy.

More specifically, in the method for producing a hot-melt powder coating agent containing a polyethylene resin as a main component, it is a modification composed of 20 to 40% by weight of the graft monomer in which an adhesive functional group is introduced into the nonpolar polyethylene resin and 30 to 70% by weight of the adhesive resin. Polyethylene is used as the main resin, and a non-halogen hybrid flame retardant is added to the mixture of 5 to 30% by weight of a mixture of an organophosphorus flame retardant and an inorganic flame retardant.

Hereinafter, the present invention will be described in more detail.

In the main resin graft copolymer of the present invention, peroxide is added to high density polyethylene (HDPE) to break ethylene bonds and generate radicals, and maleic hydride is used as a grafting agent. (MAH, maleic anhydride) is introduced into the radical of the broken ethylene bond to obtain a graftomer.

In addition, the adhesive resin to the graft polymer is low density polyethylene (LDPE, low density polyethylene), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE, medium density polyethylene), polycarbonate (PC, polycarbonate) , At least one of ethylene vinyl acetate (EVA), polyethylene terephthalate (PET, polyethylene terephthalate), butadiene rubber (BR, butadien rubber), and styrene ethylene butadiene styrene (SEBS) Good to do.

In addition, the organophosphorus flame retardant used in the present invention is in the group of phosphorus content of about 25-30% ammonium polyphosphate (APP, ammonium polyphosphate), melamine phosphate (MP, melamine phosphate), organophorus ester (organophorus ester), etc. One to two or more of the belonging may be selected, and in view of the particle size of the final powder coating composition 300㎛ or less, characterized in that the particle size of the organophosphorus flame retardant is 1 ~ 20㎛, more preferably It is good that it is 5-10 micrometers.

As the inorganic flame retardant in the present invention, at least one or two or more kinds may be used in the group consisting of aluminum hydroxide, magnesium hydroxide, calcium hydroxide, zinc borate compound, and molybdenum compound, wherein the particle size of the inorganic flame retardant is 1-20 μm. Thing, More preferably, it is 5-10 micrometers.

When the particle size of the organophosphorus and inorganic flame retardant is less than 1 μm, the load in the extruder increases when the main resin and the compound are mixed, so that workability may be degraded or uniform dispersion may be difficult. When the particle size is larger than 20 μm, coating properties may be uneven. It is not preferable because it may cause the appearance quality to deteriorate.

In addition, the flame retardant has a hybrid form of a mixture of organophosphorus and inorganic flame retardant, wherein the organophosphorous flame retardant is characterized by the formation of carbonaceous char during the pyrolysis process, making it difficult to burn, inorganic type having a flame retardant characteristics by the hydration reaction Since the effective flame retardancy can be expressed in a smaller amount when mixed with the flame retardant, in the present invention, the organophosphorus-based and inorganic flame retardants are mixed.

The non-halogen hybrid flame retardant is added to 5 to 30% by weight relative to the total composition, preferably 5 to 20% by weight is used. If the content of the flame retardant composition is 5% by weight or less, it is difficult to expect flame retardancy, while if it exceeds 20% by weight, compounding in a twin screw extruder is difficult, which may lower the mechanical properties of the plastic, which is the main resin. .

Hereinafter, with reference to the accompanying drawings will be described in detail a thermoplastic powder coating containing a non-halogen halide flame retardant according to a preferred embodiment of the present invention and a manufacturing method thereof.

In Figure 1, the manufacturing method of the thermoplastic powder coating agent containing a non-halogen hybrid flame retardant according to an embodiment of the present invention step (101), the main compound of the graft resin, the compounding of the graft monomer and the adhesive resin and the flame retardant composition It can be divided into the step (102), the grinding (103 ~ 106) step. In general, the non-halogen flame-retardant coating agent is imparted in the compounding step 102 to impart the properties to improve the adhesion of the coating agent in the graft copolymer manufacturing step 101 and to mix the prepared graft polymer, the adhesive resin and the flame retardant composition. After completing the composition, in the coarse grinding step 103 to grind the particle size of the powder to 500 ~ 1,000㎛, in the fine grinding 104 step to grind the powder particle size to 300㎛ or less, to adjust the particle size 105 Through the steps to prepare a flame retardant powder coating preferably having a particle size in the range of 100 ~ 250㎛. In addition, the powder having a particle size outside the range of 100 ~ 250㎛ in the particle size adjustment 105 step is collected and recovered, it is preferable to include the step of conveying back 106 to the fine grinding 104 step.

Specifically, first, the grafting step manufacturing step 101 is a step of modifying a non-polar polyethylene (hereinafter referred to as PE) to prepare a polar grafting agent used as a main resin in the manufacturing process.

That is, peroxide is added to PE to break ethylene bonds to form radicals, and MAH (maleic anhydride) is introduced to ethylene bonds as a grafting agent for introducing polar groups. It will be prepared a graftomer (graftomer) having.

In other words, under high temperature and high pressure conditions of a twin extruder, peroxides (reaction initiators) generate monomer radicals capable of grafting with polar components. It is combined with a polar group to produce a graftomer.

It is preferable to use 20 to 40% by weight of the graftomer having a melt index of 5 to 20g / 10 minutes, and when the content of the graftomer is less than 20% by weight, the adhesive strength is weak, and when the amount is 40% by weight or more, the degree of crosslinking between resins is excessive. Due to the rise, the melt index of the final compounded composition is low, which makes it difficult to express uniform melt coatability.

At this time, high density polyethylene (HDPE) may be used as the initial non-polar PE, and antioxidants and color pigments may be added as additives in addition to MAH and peroxide.

In addition, the processing temperature of the twin screw extruder (75 mm, L / D = 24: 1) used in the present invention is 210 ~ 230 ℃. Compound step 102 is ammonium polyphosphate (APP, ammonium polyphosphate), melamine phosphate (MP), organophorus ester (organophorus ester), aluminum hydroxide, magnesium hydroxide, calcium hydroxide, One or two or more of those belonging to the group of zinc borate compounds, molybdenum compounds, etc. are mixed, and the adhesive resins are low density polyethylene (LDPE, low density polyethylene), linear low density polyethylene (LLDPE, linear low density polyethylene) Medium density polyethylene (MDPE), polycarbonate (PC, polycarbonate), ethylene vinyl acetate (EVA, ethylene vinyl acetate), polyethylene terephthalate (PET), butadien rubber (BR, butadien rubber), styrene ethylene At least one of adhesive resins such as butadiene styrene (SEBS, styrene etylene butadiene styrene) It is a compound, including the step of manufacturing in the form of pellets, wherein the thermoplastic powder coating agent may be added to select the adhesive resin so as to have a suitable melt coating property after adhered to the preheated metal coating.

The melt index of the final powder coating agent is preferably 5 to 30 g / 10 minutes. If the melt index is lower than 5 g / 10 minutes, the coating surface is not uniform due to lack of melt flowability of the powder coating agent. Since the molten powder coating agent does not maintain the thickness, it is difficult to obtain a desired coating film.

In addition, the compounding process is a pigment pigment such as titanium dioxide, carbon black, phthalocyanine, etc., which is not chemically reactive and has excellent heat resistance for coloring the final coating composition. ˜5% by weight may be added and a powder size of 1-20 μm is preferred.

As described above, the thermoplastic powder coating composition containing the non-halogen flame retardant prepared in the form of pellets through the compound step 102 is a primary powdering step having a particle size of about 500 to 1,000 μm by using a mechanical grinding method, that is, Coarse grinding step 103 is passed. The powder crushed through the above process has a particle distribution of 300 μm or less through the fine grinding step 104, and through the particle size adjusting step 105 of adjusting the particle size and distribution for uniformity of the coating thickness and surface. The final coating agent produces a thermoplastic powder coating composition having a range of 100-250 μm.

Hereinafter, the action of the preferred embodiment of the thermoplastic powder coating composition containing the non-halogen flame retardant according to the present invention configured as described above and the reporting method thereof will be described in detail. The following examples are merely provided to explain the present invention in more detail, whereby the technical scope of the present invention is not limited.

Example

[Unit = weight%] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Graftomer 30 30 30 20 40 APP 5 10 15 20 - Mg (OH) ₂ 15 10 5 20 - LDPE 10 10 10 10 15 LLDPE 5 5 5 5 10 PC 5 5 5 5 5 EVA 20 20 20 10 20 BR 5 5 5 5 5 SEBS 5 5 5 5 5 Antioxidant 1,000 ppm 1,000 ppm 1,000 ppm 1,000 ppm 1,000 ppm

APP: phosphorus content 25 ~ 30%, nitrogen content 14 ~ 15%, average particle size less than 10㎛

Mg (OH) ₂ : average particle size less than 10㎛

LDPE: MI = 1 ~ 4.0, density = 0.920 ~ 0.924

LLDPE: MI = 1 ~ 5.0, density = 0.920 ~ 0.934

PC: Molecular Weight 10,000 ~ 35,000

EVA: MI = 1 ~ 20.0, VA content = 11 ~ 28%

SEBS: styrene content = 10 ~ 20%

BR: Mooney viscosity = 40 ~ 50

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Adhesive strength
(kgf / 25mm) KS F 4737 15.0 16.1 14.6 7.5 26.4 Impact resistance
(500g, 30cm) JIS K 5600 clear clear clear clear clear Flex resistance
(Φ2mm) JIS K 5600 Good Good Good Peeled Good Flammability UL-94 V-2 V-0 V-0 V-0 Combustion Drip resistance △ ○ ○ ○ ×

[Flame retardancy test]

◎ Related Standards: UL-94

◎ Test method: Measure the burning time after placing the specimen vertically 125mm long, 13mm long, 3.2mm thick, apply the fire for the first 10 seconds, measure the burning time after the fire for the second 10 seconds, and after the second light goes out The remaining time until the sparks disappear, and the measurement of cotton ignition

◎ Criteria:-Burning time: 10 seconds or less (V-0 grade)

              -Residual time: 30 seconds or less (V-0 grade)

              -Whether or not to ignite: No ignition of cotton by falling objects (V-0 grade)

              -Drip resistance: ○ (No drip)

                           △ (partial drip occurrence)

                           × (drip occurrence)

As shown in the table, in Examples 1 to 3, the flame retardant composition was 20% by weight, and the content of ammonium polyphosphate was 5% by weight. The results showed that, in Example 2 and Example 3, the flame retardancy according to the V-0 rating was secured within 10 seconds of the combustible time, and the adhesive strength, the impact resistance, and the flex resistance were confirmed to be excellent results.

As shown in Comparative Example 1, when the content of the flame retardant composition reaches 40% by weight, it was confirmed that the flame retardancy was excellent but the adhesive strength was lowered, and Comparative Example 2 was not flame retardant at all when there is no flame retardant composition .

1 is a flow chart showing a method for producing a thermoplastic powder coating composition containing a non-halogen hybrid flame retardant according to an embodiment of the present invention.

Claims (3)

In the manufacturing method of a flame-retardant powder coating composition containing a thermoplastic resin as a main resin, (a) modifying non-polar polyethylene and using it as a main resin; (b) compounding the grafting agent, the adhesive resin, the phosphorus flame retardant and the inorganic flame retardant by using a hybrid mixture; (c) coarsely pulverizing the compounded flame retardant coating composition to 500 to 1,000 µm or less, and pulverizing it to powder to 300 µm or less; And (d) adjusting the particle size of the differentiated compound in the range of 100 to 250 μm; a method of preparing a thermoplastic powder coating composition containing a non-halogen hybrid flame retardant. The method of claim 1, The manufacturing method of the thermoplastic powder coating composition containing the non-halogen hybrid flame retardant is a modified resin composed of 20 to 40% by weight of the graft monomer and 30 to 70% by weight of the adhesive resin into the non-polar polyethylene resin as a main resin A method for producing a thermoplastic powder coating composition containing a non-halogen hybrid flame retardant, wherein the non-halogen hybrid flame retardant is added to a mixture of an organophosphorus flame retardant and an inorganic flame retardant. 3. The method of claim 2, The non-halogen hybrid flame retardant is made by mixing an organophosphorus flame retardant and an inorganic flame retardant, The organophosphorus flame retardant is at least one selected from the group consisting of ammonium polyphosphate (APP, ammonium polyphosphate), melamine phosphate (MP, melamine phosphate), organophorus ester (organophorus ester), The inorganic flame retardant is a method for producing a thermoplastic powder coating composition containing a non-halogen hybrid flame retardant, characterized in that at least one selected from the group consisting of aluminum hydroxide, magnesium hydroxide, calcium hydroxide, zinc borate compound, molybdenum compound.

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