KR100955658B1 - Method for recycling waste powdery paints, reclaimed powdery paints for special pattern and manufacturing method of the same - Google Patents

Abstract

PURPOSE: A manufacturing method of reclaimed powdery paints for special pattern is provided to improve the reuse range of recycled powder paint, and to maintain a conventional powdery paint manufacturing method without a deformation of a melting extruder. CONSTITUTION: A manufacturing method of reclaimed powdery paints for special pattern comprises the following steps: obtaining pre-dispersed waste powdery paint by adding 5~10wt% of solvent including hydroxyl group as a catalyst to 90~95wt% of waste powder paint including a leveling additive; mixing the pre-dispersed waste powdery paint with virgin reclaimed powdery paints for special pattern including a special pattern additive and forming a solid chips by extruding the mixture; and crushing the solid chips.

Description

Method for recycling waste powdery paints, reclaimed powdery paints for special pattern and manufacturing method of the same}

The present invention relates to a method for producing recycled special pattern powder coating, and in particular, a method for reprocessing waste powder coating containing powder coating containing leveling additive in recovered powder coating and obtained by mixing it with the virgin special pattern powder coating. The present invention relates to a method for producing recycled special pattern powder coating.

Powder coating, unlike liquid paint, has the advantage of less poisoning or fire hazard by solvents, and easy painting work. There are various kinds of powder coatings, but among them, epoxy-based paints made of epoxy resins, epoxy-polyester-based paints in which epoxy resins and polyester resins are mixed at a predetermined ratio, and polyester-based paints whose resin components are only polyester resins. Prevails. In the case of using such a powder coating, the powder coating is adhered to the coated object by a method such as electrostatic coating and then heat treated. At this time, the resin component of the coating is crosslinked by heat to cure the coating film.

In addition, the powder coating is not produced crosslinking of the resin components even when exposed to sunlight for a long time during storage and use or for a long time at a predetermined temperature, it is generally prepared to crosslink the resin components in the temperature range of 160 ~ 250 ℃.

Unlike liquid paints, such powder paints are once used in a particular color, so they can be used in different colors by mixing paints with different colors. In addition, powder coating has a large amount of paint lost due to falling in the coating booth during painting, but in the case of painting a variety of colors in one coating booth, all of the paints are discarded because they are difficult to recycle because they are contaminated with various colors. There is a situation.

Wastes of such powder coatings are designated wastes and should be pyrolyzed. Therefore, manufacturers deal with powder paint waste at a high cost, which is expensive even when handling powder paint waste, but this is not a significant resource waste in that powder paint is manufactured using a very high quality raw material. Can't.

To this end, efforts are made to recycle the waste powder paints. The recycling techniques of the recovered powder coatings so far are the recycling techniques of the recovered powder coatings excluding the special pattern powder coating.

However, most of the recovered powder coatings used for painting at the site contain special pattern powder coating, which is the biggest problem in recycling powder coating, which is separated or recycled without separation. No technique is known at present.

In general, the recycling of the recovered powder coating is a technique for controlling the extrusion conditions. Specifically, a melt extruder manufactured to be suitable for recycling the recovered powder coating is used rather than an extruder used in a general powder coating manufacturing method. Due to the difference in dispersibility when the special melt extruder is used for the production of general powder coatings, not recycled powder coatings, the obtained powder coatings do not show 100% consistency with the general powder coatings in terms of texture and gloss appearance. .

In addition, when existing recycled powder coating recycling manufacturing technology is used for recycling special pattern recovered powder coating, the occurrence of cratering (crater phenomena), pin holes (needle marks), and unevenness of gloss appear in the final coating. And compatibility problems.

On the other hand, in general powder coatings include leveling additives, and recycled powder coatings obtained by recycling recovered powder coatings containing leveling additives are different from virgin special pattern powder coatings when used in the manufacture of recycled special pattern powder coatings. There is a problem that the formation of the pattern is not made properly.

One embodiment of the present invention provides a method for easily recycling the waste powder paint containing a leveling agent.

In one embodiment of the present invention is to recycle the waste powder coating containing a leveling agent, to provide a recycled special pattern powder coating without inhibiting the pattern formation.

In one embodiment of the present invention to provide a method for producing a recycled special pattern powder coating that can be produced as a solid chip using a melt extruder that has been used in general powder coating from a waste powder coating containing a leveling agent.

In one embodiment of the present invention is added to 5 to 10% by weight of the catalyst containing a hydroxyl group to 90 to 95% by weight of the waste powder coating containing a leveling additive and dispersed using a sambon roll mill to reprocess the waste powder coating Provide a way to.

In the waste powder coating reprocessing method according to an embodiment of the present invention, the solvent containing a hydroxyl group may be selected from methanol, ethanol and phenol.

One embodiment of the present invention provides a reclaimed special pattern powder coating comprising a reprocessed waste powder coating obtained by the above embodiment. In a specific embodiment, the recycled special pattern powder coating is added to 90 to 95% by weight of the waste powder coating containing a leveling additive and 5 to 10% by weight of a catalyst which is a solvent containing a hydroxyl group. Treated waste powder coating; It may include a virgin special pattern powder coating composition that does not include a leveling additive and includes a special pattern additive.

In one embodiment of the present invention to the waste powder coating containing a leveling additive 5 to 10% by weight of a catalyst comprising a hydroxyl group to 90 to 95% by weight of the waste powder coating and dispersed by using a three-mill roll mill pre-dispersed waste powder coating Obtaining (S1); A virgin special pattern powder coating composition containing no leveling additive and including a special pattern additive, mixing and melt-extruding the pre-dispersed waste powder coating to form a solid chip (S2); And it provides a method for producing a recycled special pattern powder coating comprising the step (S3) of grinding the molded solid phase chip.

In the method for producing a recycled special pattern powder coating according to an embodiment of the present invention, the solvent containing a hydroxyl group may be selected from methanol, ethanol and phenol.

In the method for producing a recycled special pattern powder coating according to an embodiment of the present invention, the virgin special pattern powder coating composition in S2 may include a main body, a curing agent, a curing accelerator, a pigment, and an additive.

In the method for producing a recycled special pattern powder coating according to an embodiment of the present invention, the pre-dispersed waste powder coating in S2 may include up to 60% by weight of the solid phase chip weight.

In the method for producing a reclaimed special pattern powder coating according to an embodiment of the present invention, the melt extrusion in S2 may be carried out under 95 to 110 ℃, shear rate 40 to 50rpm conditions.

According to one embodiment of the present invention, it is possible to manufacture recycled powder coating including recycled powder coating while widening the recycling range of recovered powder coating, and also maintaining the existing powder coating method without modifying the melt extruder using the same. The obtained reclaimed powder coating is mixed with the special pattern powder coating to have an excellent pattern formation property equivalent to or higher than that of a product made of a virgin special pattern powder coating.

Epoxy powder coating, polyester powder coating and epoxy-polyester powder coating are the most widely used and most recovered powder coatings in the powder coating market, and these three powder coatings are coated and recovered in the workplace. .

In addition, powder coatings are most often including leveling additives as additives, except in special cases.

However, when the recycled special pattern powder coating composition is produced together with the virgin special pattern powder coating composition by recycling the waste powder coating including the leveling additive, it causes a problem in pattern formation unlike the virgin special pattern powder coating.

Currently, most of the special pattern powder coatings manufactured and used include hammatone powder coating, texture powder coating, and structure powder coating, which include a pattern-forming additive which may include a special pattern. Form a pattern for each feature, including "." The special pattern powder coating excludes the leveling additive as an additive, unlike the general powder coating, because the leveling additive impedes the function of the special pattern additive to inhibit the formation of the pattern.

For this reason, even if the waste powder coating containing some leveling additives is recycled, there is a limit to applying it to the production of recycled special pattern powder coating.

In one embodiment of the present invention, a catalyst is applied in reprocessing the waste powder paint, in which a plurality of powder paints, which may include a leveling additive, is subjected to a pre-dispersion process prior to the powder coating process. Specifically, in the waste powder coating reprocessing method according to one embodiment of the present invention, 5 to 10 wt% of a catalyst including a hydroxyl group is added to 90 to 95 wt% of the waste powder coating containing a leveling additive, It includes the step of dispersing by using. Dispersion process using a three-bone roll mill proceeds at room temperature without setting a special temperature conditions, it is possible to obtain a dispersion of about 40 ℃ by frictional heat in the process of dispersion. The reason why the three-bone roll mill is used in the dispersing process is to use a three-bone roll mill having high dispersibility at high viscosity because the viscosity of the mixture with the waste powder coating is high because the catalyst used as the solvent containing the hydroxyl group is used in an amount of 5 to 10% by weight. .

An example of the molecular structure of the epoxy resin used in the general powder coating may be as shown in the following formula (1).

Formula 1

Such epoxy resins usually undergo a curing reaction when heat is applied to form a coating film. Referring to the curing mechanism in general powder coating,

For example, the curing reaction between the epoxy resin and the phenolic curing agent (R1-OH) may be the same as in Scheme 1.

Scheme 1

In addition, the curing reaction of the epoxy resin and the primary amine curing agent is shown in Scheme 2, and the curing reaction of the secondary amine curing agent can be shown in Scheme 3.

Scheme 2

Scheme 3

On the other hand, the curing reaction of the epoxy resin and the polyester resin can be represented by the following reaction schemes 4 to 6.

Scheme 4

Scheme 5

Scheme 6

In addition, the curing reaction between the polyester resin and TGIC can be represented by the following scheme 7.

Scheme 7

In the process of manufacturing recycled powder coating using waste powder coating, it is possible to influence the uncured products in the waste powder coating. In view of this problem, the present invention reacts with general powder coating raw materials after manufacture of recycled powder coating. In order to solve the limit of recycling of special pattern collection powder coating by removing possible elements, the catalyst is re-processed by adding a catalyst to promote the curing reaction in the powder coating.

The catalyst that can be used to reprocess the waste powder coating is a solvent containing a hydroxyl group, and examples thereof include methanol, ethanol or phenol. Among them, ethanol may be more advantageous as a catalyst in that it is safer and more industrially treated than methanol and phenol.

When the catalyst, which is a solvent containing such a hydroxyl group, is mixed and dispersed with the waste powder paint, the hydroxyl group is a catalyst in the reaction between the epoxy group and the curing agent components of the epoxy resin which constitute the main component of the waste powder paint and the carboxyl group of the polyester resin. It acts as a catalyst for chemical reactions without affecting the structure of the material.

In particular, the leveling additive contained in the reprocessed waste powder paint acts as a deterrent to the pattern formation of the special pattern powder paint. Therefore, the leveling additive in the reprocessed waste powder paint by preliminary reaction of the waste powder paint through a pre-dispersion process. Can inhibit the action of.

Here, the curing reaction does not occur simply by blending with the catalyst, and is possible when the temperature condition is 30 ° C. or higher. An example of a preferable dispersing method is a method of dispersing the waste powder coating and the catalyst using a roller mill.

At this time, when the amount of the catalyst applied exceeds 10% by weight, after dispersing with the waste powder coating, the powder is formed into a solid chip form through a melt extrusion process during the regeneration powder coating process and then subjected to a grinding process. It is not possible to apply chip production in the form of high viscosity gel, so it is not applicable to the production of recycled powder coating. Therefore, the preferred amount of catalyst is 5 to 15% by weight, the waste powder coating amount is 90 to 95% by weight.

As an example of this, a ternary roll mill (manufactured by Jinsung Machinery Co., Ltd.) is used by using ethanol as a catalyst and mixing a powdered powder containing an ethanol catalyst and a leveling additive in a weight ratio of 5:95 / 10:90 / 15:85 / 20:80. Pre-dispersed by using the waste powder coating was prepared. It is not easy to identify the type and amount of leveling additives contained in the waste powder paint, but in general, the general paint powder coating other than the special pattern powder paint is 0.1% to 3% by weight based on the total amount. The leveling additive may be included in the waste powder coating because the leveling additive may be included according to the characteristics of the manufacturer's product.

The quality of the reprocessed waste powder coating was evaluated by the influence on the surface, gloss and physical properties of the final product, and visually evaluated for the pattern formation. The results are shown in Table 1 below.

Waste Powder Coating Content (wt%) Catalyst (ethanol) content (% by weight) Final product quality Pattern formation 95 5 clear clear 90 10 clear clear 85 15 Bad Bad 80 20 Bad Bad

From the results in Table 1, it can be seen that the preferred amount of catalyst in reprocessing the waste powder coating is 5 to 10% by weight.

In this way, recycled special powder coating can be manufactured using reprocessed waste powder coating. At this time, regenerated powder coating can be manufactured using only reprocessed waste powder coating. It may be prepared by mixing with the special pattern powder coating composition to reproduce the special pattern powder coating.

The method of manufacturing recycled special pattern powder coating by mixing with the virgin special pattern powder coating composition from the reprocessed waste powder coating is similar to the general powder coating process. The reprocessed waste powder coating and the virgin special pattern powder coating composition are A melt-extruded product using a melt extruder for powder coating manufacturing is molded into a solid chip, and then pulverized to obtain a recycled special pattern powder coating.

At this time, the melt extrusion conditions are similar to the melt extrusion conditions in general powder coating production, it can be melt-extruded under the conditions of shear rate 40 to 50rpm at a temperature condition of 95 to 110 ℃.

The above and below 'virgin special pattern powder coating composition' includes a special pattern additive without a leveling agent, and in addition to the virgin special pattern powder coating component including a main agent and a curing agent, a general accelerator including a curing accelerator, a pigment and an additive It will be understood as a powder coating composition.

In consideration of the working time of the finally obtained regenerated powder coating, it may be desirable that the reprocessed powder coating in the solid chip is 60% by weight or less.

It can be molded into solid chips and then pulverized to obtain a reclaimed special pattern powder coating. The grinding may be applied in the same manner as in the production of a conventional powder coating, and an example thereof may be a grinding using ACM MILL.

In order to evaluate the physical properties of the regenerated special pattern powder coating using the reprocessed waste powder coating according to an embodiment of the present invention, a regenerated special pattern powder coating was prepared by the following method.

As an example, the powder coating which is painted and discarded at the painting work site is collected regardless of the type of paint. At this time, the collected powder coating does not include a special pattern, but more than 90% of the coating material that forms a special pattern such as hamaton, structure, texture, etc., together with a leveling additive.

The waste powder paint containing the collected leveling additives is pre-dispersed under a ethanol catalyst using a three-stage roll mill to cause curing reaction of the resin contained in the waste powder paint so that it will no longer affect the appearance or properties of the coating film during recycling. It was. In particular, by suppressing the action of the leveling additive in the waste powder coating to prevent adverse effects on the pattern formation and physical properties.

In preparing the recycled special pattern powder coating using the reprocessed waste powder coating thus obtained, the virgin special pattern powder coating composition used for physical property comparison is as follows. % Will be understood as weight percent below.

Polyester resin-40%

Epoxy resin-20%

TC 001 (Product Name) Curing Accelerator-0.4%

Special Pattern Additive-0.2%

BENZOIN additives-0.5%

WAX additive-0.5%

Barium sulfate-11.3%

Calcium Carbonate-5%

Titanium dioxide-22%

FreeCol Yellow 1000-0.1%

100% in total

Using the virgin special pattern powder coating composition, the powder coating was manufactured and tested through a melt extrusion and grinding process (40 μm) under a condition of 95 to 110 ° C. at a shear rate of 40 to 50 rpm, as shown in Table 2 below.

Item Test matter Test result Remarks Dry coating state No abnormality in appearance clear Visual judgment Polish 60 ° 88% 60 ° GLOSS Tester Pencil hardness F or more H MISUBISHI UNI CROSS CUT 100/100 100/100 ERICHSEN Exam No crack at 6mm clear ERICHSEN Testing Machine Impact test 500g / 50cm not to be broken clear Dupont impact Acid resistance test Coating state after 240 hours immersion clear 5% H ₂ SO ₄ Salt water spray test Peeling state after 240 hours immersion 3mm or less 5% NaCl Fog / 35 ℃ Alkali resistance test Coating state after 240 hours immersion clear 5% NaOH Boiling water resistance 98 ㅁ 2 ℃ * 1 hour coating state clear Structure No abnormality in pattern formation clear Visual judgment

On the other hand, by applying the reprocessed powder coating (reprocessed using 5% by weight of catalyst, including leveling additives) and blended with the virgin special pattern powder coating composition in the following mixing ratio and melt extrusion and grinding process in the same manner as described above (40㎛) through the manufacturing and testing the reclaimed special pattern powder coating is shown in Table 3 below:

Polyester resin-20%

Epoxy resin-10%

TC 001 (Product Name) Hardener-0.2%

Special Pattern Additive-0.1%

BENZOIN additive-0.25%

WAX additive-0.25%

Barium sulfate-5.65%

Calcium Carbonate-2.5%

Titanium dioxide-11%

FreeCol Yellow 1000-0.05%

Reprocessed Waste Powder Coating-50%

100% (mass%) in total

Item Test matter Test result Remarks Dry coating state No abnormality in appearance clear Visual judgment Polish 60 ° 90% 60 ° GLOSS Tester Pencil hardness F or more H MISUBISHI UNI CROSS CUT 100/100 100/100 ERICHSEN Exam No crack at 6mm clear ERICHSEN Testing Machine Impact test 500g / 50cm not to be broken clear Dupont impact Acid resistance test Coating state after 240 hours immersion clear 5% H ₂ SO ₄ Salt water spray test Peeling state after 240 hours immersion 3mm or less 5% NaCl Fog / 35 ℃ Alkali resistance test Coating state after 240 hours immersion clear 5% NaOH Boiling water resistance 98 ㅁ 2 ℃ * 1 hour coating state clear Structure No abnormality in pattern formation clear Visual judgment

In addition, by applying another reprocessed powder coating (reprocessed using 10% by weight of catalyst, including leveling additives) and blended with the virgin special pattern powder coating composition in the following compounding ratio and melt-extruded and The powder coating was prepared and tested through a grinding process (40 μm), as shown in Table 4 below:

Polyester resin-20%

Epoxy resin-10%

TC 001 (Product Name) Hardener-0.2%

Special Pattern Additive-0.1%

BENZOIN additive-0.25%

WAX additive-0.25%

Barium sulfate-5.65%

Calcium Carbonate-2.5%

Titanium dioxide-11%

FreeCol Yellow 1000-0.05%

Reprocessed Waste Powder Coating-50%

100% (mass%) in total

Item Test matter Test result Remarks Dry coating state No abnormality in appearance clear Visual judgment Polish 60 ° 89% 60 ° GLOSS Tester Pencil hardness F or more H MISUBISHI UNI CROSS CUT 100/100 100/100 ERICHSEN Exam No crack at 6mm clear ERICHSEN Testing Machine Impact test 500g / 50cm not to be broken clear Dupont impact Acid resistance test Coating state after 240 hours immersion clear 5% H ₂ SO ₄ Salt water spray test Peeling state after 240 hours immersion 3mm or less 5% NaCl Fog / 35 ℃ Alkali resistance test Coating state after 240 hours immersion clear 5% NaOH Boiling water resistance 98 ㅁ 2 ℃ * 1 hour coating state clear Structure No abnormality in pattern formation clear Visual judgment

As described above, the catalyst used as a solvent containing a hydroxyl group is pre-dispersed and reprocessed by dispersing the waste powder coating containing the leveling additive, and then applied to the general powder coating manufacturing process to produce the reclaimed special pattern powder coating. It can be seen that it has a physical property equivalent to or higher than that of the powder coating obtained by using the special pattern powder coating composition, and that the pattern formation property can also be produced with a regenerated special pattern powder coating.

Claims (9)

delete delete delete delete 90 to 95% by weight of the waste powder coating comprising a leveling additive, adding 5 to 10% by weight of a catalyst comprising a hydroxyl group and dispersing using a three-mill roll mill to obtain a pre-dispersed waste powder coating (S1); A virgin special pattern powder coating composition containing no leveling additive and including a special pattern additive, mixing and melt-extruding the pre-dispersed waste powder coating to form a solid chip (S2); And Method for producing a reclaimed special pattern powder coating comprising the step of grinding the molded solid chip (S3). The method of claim 5, wherein the solvent comprising a hydroxyl group is selected from methanol, ethanol and phenol. The method of claim 5, wherein the virgin special pattern powder coating composition in S2 comprises a main body, a curing agent, a curing accelerator, a pigment, and an additive. The method for producing a reclaimed special pattern powder coating as claimed in claim 5, wherein the powdered powder coating pre-dispersed in S2 is included in a maximum of 60% by weight based on the weight of the solid phase chip. The method of claim 5, wherein the melt extrusion in S2 is carried out under 95 to 110 ℃, shear rate of 40 to 50rpm conditions.