KR100526486B1 - Manufacturing method of high weathering semi-gloss powder coating - Google Patents

Abstract

The present invention relates to a method for producing a high weathering semi-glow powder coating, and more specifically, (1) hydroxy of 29 to 57% by weight polyester resin having two different functional groups at the end, equivalent to 70 to 600 hydroxy Or 1 to 20% by weight of a curing agent having an epoxy group, 1 to 10% by weight of a methoxy group having a -NCO equivalent of 80 to 350 or a curing agent having a -NCO group, 26 to 32% by weight of titanium dioxide, 18% by weight or less of an extender pigment, and quenching 5 wt% or less, and 18 wt% or less of other additives are injected into a premixing tank, premixed, melt dispersed at 90-130 ° C. in a disperser, pulverized with a high speed mixer, and filtered through 100-340 mesh to prepare a paint. step; (2) 34 to 56% by weight of a polyester resin having only a carboxyl group, 1 to 17% by weight of a curing agent having a hydroxy or epoxy group having an equivalent of 70 to 350, 26 to 32% by weight of titanium dioxide, and 18% by weight of a extender pigment, 5 wt% or less of quencher, and 6 wt% or less of other additives are inserted into a premixing tank, premixed, melt dispersed at 90-130 ° C. in a disperser, pulverized with a high speed mixer, and filtered through 100-340 mesh to prepare a paint. Doing; And (3) mixing the paints of steps (1) and (2) in a mixing ratio of 2/8 to 8/2, followed by dry blending.

Description

Manufacturing method of high weathering semi-gloss powder coating

The present invention relates to a method for producing a high weather resistance semi-glow powder coating, and more particularly, to a polyester resin having a carboxyl group and a hydroxyl group at the same time (hereinafter, "polyester having two different functional groups at the end" Resin "and a polyester resin having only a carboxyl group, and a powder coating having excellent weather resistance, stain resistance, leveling, baking temperature and gloss stability by coating thickness. The gloss of the powder coating according to the present invention is set to about 10 to 30% based on a 60 ° gloss system at 200 ° C × 10 minutes (based on M.P.T).

Conventional semi-gloss powder coatings can be classified into several types depending on the intended use. Firstly, in the case of indoors, carboxy polyester resin, epoxy curing agent and matting agent are mainly used. Second, urethane curing agent is used in two kinds of hydroxy polyester resins having different reactivity. Third, for outdoor use where weather resistance is required. For application, triglycidyl isocyanurate or G.A. acryl is used as a carboxy polyester resin and a curing agent, and a system using a matting agent or two paints having different reactivity are mixed at an appropriate ratio. I used the method mainly.

In the first case described above, since the weather resistance is very poor, there is no record of use for outdoor use. In the second case, there is an appropriate level of weatherability and excellent leveling depending on the formulation, but the storage property is poor and a blocking agent is generated during the curing reaction. Pollution is a problem, but the third case is the most widely used for outdoor use.

However, even in the third case, a satisfactory result is not obtained in terms of leveling, fouling resistance, or weather resistance, and when the semi-manufacture is made of paint alone, there is a problem in that the stability of gloss at each baking temperature is inferior. Therefore, the existing high weathering semi-gloss paints have been applied only to very limited elements, and there is little application of outdoor aluminum panels.

In order to compensate for the above problems, the present invention uses two kinds of resins having different reactivity such that thermal resin, crosslink, resin melt viscosity, glass transition temperature, softening point, etc. are balanced. Semi-gloss was possible only when the reactivity between them differed by a certain level or more. Therefore, in the present invention, it is possible to have a difference in compatibility and reactivity between the curing agents used, and in order to improve the stain resistance, two different functional groups at high reactivity terminals which increase the crosslinking density of the resin itself and the crosslinking density of the coating film are increased. Semi-gloss powder with excellent gloss stability with excellent appearance, chemical resistance, especially weather resistance and fouling resistance by selecting resins having only carboxyl groups with slow reactivity and resins having very high flowability and preparing the paints and dry blending them at an appropriate ratio. Paints could be produced.

Accordingly, an object of the present invention is to provide a powder coating method having excellent weather resistance, stain resistance, leveling, baking temperature, and gloss stability by coating film thickness.

The production method of the present invention for achieving the above object (1) 29 to 57% by weight of a polyester resin having two different functional groups at the end, a curing agent 1 to 20 having a hydroxy or epoxy group having an equivalent of 70 to 600 % By weight, 1 to 10% by weight of a curing agent having a methoxy group or -NCO equivalent of 80 to 350, or -NCO group, 26 to 32% by weight of titanium dioxide, 18% by weight or less of a pigment pigment, 5% by weight or less of a matting agent, and others 18 wt% or less of the additive is injected into a premixing tank, premixed, melt dispersed at 90-130 ° C. in a disperser, pulverized with a high speed mixer and filtered at 100-340 mesh to prepare a paint; (2) 34 to 56% by weight of a polyester resin having only a carboxyl group, 1 to 17% by weight of a curing agent having a hydroxy or epoxy group having an equivalent of 70 to 350, 26 to 32% by weight of titanium dioxide, and 18% by weight of a extender pigment, 5 wt% or less of quencher, and 6 wt% or less of other additives are inserted into a premixing tank, premixed, melt dispersed at 90-130 ° C. in a disperser, pulverized with a high speed mixer, and filtered through 100-340 mesh to prepare a paint. Doing; And (3) mixing the paints of steps (1) and (2) at a mixing ratio of 2/8 to 8/2, followed by dry blending.

Looking at the present invention in more detail as follows.

According to the invention, in one step, the paint is prepared using a polyester resin having two different functional groups at the end, in the second step, the paint is prepared using a polyester resin having only a carboxyl group, and in three steps In the first step paint and the second step paint is blended at an appropriate ratio to produce a semi-glossy.

In the first step, the polyester resin having two different functional groups at the end is excellent in the weather resistance and fouling resistance of the gloss, high glass transition temperature, good flowability, good reactivity during coating and good other physical properties The resin was selected, and in the paint formulation, a weathering curing agent having a hydroxy or epoxy group, a curing agent having a methoxy group or -NCO group, a quencher, and other additives were used.

In the second step, the polyester resin having only a carboxyl group has a high glass transition temperature and excellent flowability, good gloss weather resistance, slow reactivity during coating and other properties with good physical properties. Weatherable curing agents having hydroxy or epoxy groups and other additives were used.

In the third step, the first and second paints must have appropriate gel time, respectively, so that the desired gloss and leveling can be obtained while maintaining the proper gel time when dry blending the two paints.

Referring to the paint formulation and manufacturing steps and resin properties used in the present invention in more detail as follows.

Phase 1 manufacturing

29 to 57% by weight of a polyester resin having two different functional groups at its ends, 1 to 20% by weight of a curing agent having a hydroxy or epoxy group having an equivalent of 70 to 600, a methoxy group having an NCO equivalent of 80 to 350, or- 1-10% by weight of NCO group, 26-32% by weight of titanium dioxide, 18% by weight or less of extender pigment, 5% by weight or less of matting agent, and other additives (hardening accelerator, ultraviolet absorber, Hals, antioxidant, flowability) Improving agent, and / or anti-pinhole, etc.) 18% by weight or less is injected into the premixing tank, premixed, and melt-dispersed at 90-130 ° C. in a disperser to prepare chips of appropriate thickness. The chip is then ground with a high speed mixer and filtered through 100-340 mesh to complete the paint preparation.

2-step manufacturing

34-56 weight% of polyester resin which has only carboxyl group, 1-17 weight% of hardening | curing agents which have a hydroxy or epoxy group equivalent 70-350, 26-32 weight% of titanium dioxide, 18 weight% or less of extender pigments, 5 matting agents Up to 6% by weight, and up to 6% by weight of other additives (such as ultraviolet absorbers, Hals, antioxidants, flow improvers, and / or pinhole inhibitors) are injected into the premixing tank and the paint is prepared in the same manner as in the first step preparation. .

3-step manufacturing

The paint of the present invention is prepared by sufficiently mixing the first and second paints in a container mixer at an appropriate ratio.

On the other hand, the polyester resin having two different functional groups at the end in the first step production has a hydroxy value of 10 to 30, an acid value of 15 to 35, the melt viscosity of 15 to 50 poise (200 ℃, I. Eye viscometer), N3316 (Koryo Chemical Co., Ltd.) that softening point is 115-125 degreeC, glass transition temperature is 55-75 degreeC, number average molecular weight is 1500-5000, and average number of functional groups in resin end is about 1.5-3 pieces. A-239-X (D.I. Sea Co., Ltd.) etc. can be used, and as a hardening | curing agent, Piti-810 and Piti-910 (Ciba-Geigi Co., Ltd. brand name) which have a hydroxy or epoxy group equivalent 70-600. , X.L-552 (MS), G.A.300, SYP-550 (Wolli), A-249-A (D.I. PowderLink-1174 (Scitec), B-1530, B.F-1540, -1300 (Herbs Inc.), V.P-L.S-2122 (Bayer Corp.) , 24- 2450, 24-2400 (Cargill, etc.) can be used by adjusting the equivalent ratio of the resin.

Inorganic pigments include titanium dioxide-based Al-902, -960 (Dupont), C.Al-80, -90 (Ishihara), and the extender pigments include barium sulfate, aluminum hydroxide, and silicon. Deuterium-10 H.B (Mountain), O.N-310 (Martin's Berg), Minusil-15 µm (U.S. Silica), etc. High-wax 210M.P (Samjeong Dynamic Pressure Corp.), D-3329, -3357 (Shiba-Gaigi Corp.), M.P.I-400, -440, -600 (Micro Powder I.N. Among the other additives, as a curing accelerator, Shishi-620 (U.S., Inc .: a high weathering polyester resin having an acid value of 50), N3314 (Korea Chemical Company: an accelerator having an acid value of 40-53) Contained high weathering polyester resins), organotin compounds such as dibutyltin dilaurate, triphenyl phosphine (Hoco), tetrabutyl ammo Quaternary ammonium salts such as chromium bromide, imidazoles, and 4101 (Akto Chemical Co., Ltd.), etc., and tinuvine 900, 1130 (above Shiba-Gaigi Co., Ltd.) Halogen is thinubin-114, 292, 662, 700 (Shibagaiki Co., Ltd.), Sand Dub-3055 (Sitac Co., Ltd.), etc., and antioxidants are: ganox-1076, -1010, -P.S. 800, -P.S 802, Ilga Force-168 (above Shiva-Geigi), etc., and the flow-enhancing zeros include Modaflow I (Monsanto), P.V-5, P.V-88 (Wallley), As a pinhole preventive agent, such as acronal-4-F (BASF Corporation), Benzoin (BASF Corporation), A.D.D-900, -902 (Wally), Lanco Wax P.P-1362 D (Langer company) ), Spinol-104 (Air product) and the like can be used.

The physical properties of the polyester resin having only a carboxyl group in the two-step production, the acid value is 25 to 45, the melt viscosity is 15 to 35 poise (200 ℃, I. C. eye viscometer), the softening point is 115 to 125 ℃, the glass transition temperature N3317 (Koryo Chemical Co., Ltd.), CC-630 (Yuvis Corporation) etc. which use 55-75 degreeC, a number average molecular weight 1500-4000, and the average number of functional groups at the resin terminal of about 1 or 2 can be used, Examples of the curing agent include PTI-810, PTI-910 (Ciba Geigy Co., Ltd.), X.L-552 (MS: Trade Name), G.M. 300, and the like having a hydroxyl group or an epoxy group having an equivalent weight of 70 to 350. It can be used by adjusting the equivalent ratio of resin.

Inorganic pigments include titanium dioxide-based Al-902, -960 (Dupont), C.Al-80, -90 (Ishihara), and the extender pigments include barium sulfate, aluminum hydroxide, and silicon. Deuterium-10 H.B (Mountain), O.N-310 (Martin's Berg), Minusil-15 µm (U.S. Silica), etc. HI-WAX 210M.P (Samjeong Dynamic Pressure Corp.), D.T-3329, -3357 (Shiba-Gaigi Co., Ltd.), M.P.I-400, -440, -600 (Micro Powder I.N.S. G) and the like, and among the other additives, UV absorbers, Hals, antioxidants, flow improvers, etc. may use the same raw materials as in the first step.

In the three-stage production, when the first and second stage paints are sufficiently mixed in the container mixer at a weight ratio of 2/8 to 8/2 as the final stage of the paint production, it is possible to produce a high weathering semi-glossy to be achieved in the present invention.

In addition, in order to achieve the object of the present invention, in the case of the first stage paint, the glossiness (60 ° glossmeter: less than or equal) should be 30 to 50%, and the gel time difference between the first and second stage paints may be appropriate. It should be maintained, which should be 20 to 50 seconds (@ 200 ℃) for polyester resins having two different functional groups at the end, and 240 to 360 seconds (@ 200 ℃) for polyester resins having only carboxyl groups. The gel time difference between the two paints should be 190 to 340 seconds, and the gel time of the dry blended paint should be 20 to 50 seconds. In the case of the first stage paint, when the gel time is 20 seconds or less, the leveling may be extremely bad during the second stage paint and the dry blending. When the first stage paint is 50 seconds or more, the gloss is high regardless of the gel time of the second stage paint. In addition, when the difference between the gel time of the two paints is 190 seconds or less, the leveling is lowered and the gloss comes out, and if the 340 seconds or more, the gloss is too low or mechanical properties are poor. In addition, the baking temperature of the paint prepared in step (3) is 190 ~ 200 ℃ × 10 minutes (based on M.P. T), the gloss (60 ° gloss system) is preferably 10 to 30%.

On the other hand, the gloss can reach the target level when selecting both resins having a too high melt viscosity or only a carboxyl group in the resin selection, but the leveling becomes worse, the crosslinking density of the resin itself and the crosslinking density of the coating film are lowered. It tends to be poor in contamination and weather resistance, and when the melt viscosity is too low, the gloss is too low or the storage stability of the paint is deteriorated.

When the acid value and the hydroxy value in the resin of the first step is lower than the set range, the amount of the curing agent is too small to increase the gel time to increase the gloss and the mechanical properties may be reduced, if high, the amount of the curing agent is too much gel time This is so fast that the appearance of semi-gloss may deteriorate, and may change with time during storage of the paint.

And when the acid value is lower than the above range and the hydroxy value is high, the gel time increases, and the gloss is high when the semi-preparation is produced. When the acid value is higher than the above range and the hydroxy value is low, the gel time is faster, the appearance becomes worse during the semi-glow manufacturing Problem occurs.

When the acid value in the resin of the second step is lower than the set range, the gel time increases, the gloss in semi-glossy may drop much, but the mechanical properties decrease, and when the high value is high, the gel time is faster, resulting in high gloss in semi-manufacture. . Therefore, in order to secure the gel time and the gel time difference presented in the present invention, it is possible to select a resin within the above-described physical property range.

In the use of the curing agent, the use of less than the amount of the use is less reactivity, the gloss is high or the mechanical properties and fouling resistance is lowered, when using more than the amount of the curing agent increases the pollution resistance and gloss degradation may be improved but the effect of unreacted curing agent As the chemical resistance is lowered or the reactivity is so fast that there is a problem of poor leveling, the amount of use should always be used in the same equivalence ratio against the acid value or the hydroxy value of the resin.

In the dry blending ratio of the two paints, if the first paint is less than 2 at the mixing weight ratio of the paint of 1st stage and 2nd stage, the gloss becomes high regardless of gel time, and if it exceeds 8, the leveling, mechanical properties, etc. are inferior. There is a problem, so the ratio of dry blending is very important.

Hereinafter, the effects of the present invention will be described in more detail with reference to Examples and Comparative Examples, but the scope of the present invention is not limited to the following Examples.

Examples 1-4 and Comparative Examples 1-5

The physical properties of the resin used in the following Examples and Comparative Examples were compared to Table 1 below.

TABLE 1

*: Koryo Chemical Company (Can be used as a curing accelerator or topic)

* 2: U.C.B Company

* 3: Syntech

TABLE 2

TABLE 2a

* 1: Triphenyl Phosphide

* 2: U.C.B company (1 equivalent = 700)

TABLE 3

TABLE 3a

In Tables 3 and 3a above,

* Curing condition: 200 ℃ × 10 minutes (based on M.P.T)

* Pollution resistance

① Test method: mix the carbon in water (NV = 10%), apply it on the specimen, dry it in the oven at 80 ℃ for 1 hour, and wash it with water and isopropyl alcohol.

② Criteria: Very good (solvent fluorine: 10 points) ← .............. → Very poor

   10 points ... ... 1 point

* Leveling: ◎-> Very good, ○-> Good, ○-△-> Slightly insufficient, △-> Poor, ×-> Poor

TABLE 4

TABLE 5

TABLE 6

TABLE 7

Conventional semi-gloss powder coatings have limited weathering or fouling resistance, and their use is limited to farm equipment, steel furniture, and fences. However, the paint according to the present invention, as can be seen from the above tables, it is very excellent in weather resistance, stain resistance, leveling, and can be applied for aluminum window frames or outdoor panels, which mainly used solvent-type paint in addition to the above applications.

Claims (7)

(1) 29 to 57% by weight of a polyester resin having two different functional groups at its ends, 1 to 20% by weight of a curing agent having a hydroxy or epoxy group equivalent of 70 to 600, and -NCO equivalent of methoxide having an amount of 80 to 350 1-10% by weight of a curing agent having a period or -NCO group, 26-32% by weight of titanium dioxide, 18% by weight or less of extender pigment, 5% by weight or less of matting agent, and curing accelerator, ultraviolet absorber, Hals, antioxidant, flowability 18 wt% or less of other additives selected from the group consisting of an enhancer and an anti-pinhole agent is added in a premixing tank, premixed, melted and dispersed in a disperser at 90 to 130 ° C., and then pulverized with a high speed mixer to obtain 100 to 340 mesh. Filtering to form a paint; (2) 34 to 56% by weight of a polyester resin having only a carboxyl group, 1 to 17% by weight of a curing agent having a hydroxy or epoxy group having an equivalent of 70 to 350, 26 to 32% by weight of titanium dioxide, and 18% by weight of a extender pigment, 5 wt% or less of matting agent, and 6 wt% or less of other additives selected from 1 or 2 or more selected from the group consisting of UV absorbers, Hals, antioxidants, flow improvers and pinhole inhibitors into the premixing tank, and premixed Melting and dispersing at 90 to 130 ° C. in a high speed mixer to filter the mixture to 100 to 340 mesh to prepare a paint; And (3) A method for producing a high weather resistance semi-glow powder coating, characterized in that the steps (1) and (2) are mixed in a mixing ratio of 2/8 to 8/2, followed by dry blending. The method of claim 1, wherein in the step (1), the hydroxyl value of the polyester resin having two different functional groups at the end is 10 to 30, the acid value is 15 to 35, the melt viscosity is 15 to 50 poise ( 200 ° C., I. C. Eye Viscometer), the softening point is 115-125 ° C., the glass transition temperature is 55-75 ° C., the number average molecular weight is 1500-5000, and the average number of functional groups at the resin terminal is 1.5-3. Method for producing high weathering semi-gloss powder coating. The acid value of the polyester resin having only a carboxyl group in step (2) is 25 to 45, the melt viscosity is 15 to 35 poise (200 ℃, I. C. eye viscometer), the softening point is 115 to 125 And a glass transition temperature of 55 to 75 ° C., a number average molecular weight of 1500 to 4000, and an average number of functional groups at the terminal of the resin are 1 to 2; The high weatherability semi-gloss powder coating of claim 1, wherein the gloss (60 ° gloss) of the paint of step (1) is 30-50%, and the gel time is 20-50 seconds (@ 200 ° C). Manufacturing method. The method according to claim 1, wherein the gel time of the paint of step (2) is 240 to 360 seconds (@ 200 ° C). The gel time difference between the two paints before dry blending in step (3) is 190 to 340 seconds (@ 200 ° C), and the gel time of the paint after dry blending is 20 to 60 seconds (@ 200). Method for producing a high weather resistance semi-glow powder coating, characterized in that (c). According to claim 1, wherein the baking temperature of the paint in the step (3) is 190 ~ 200 ℃ × 10 minutes (based on M.P. tea), the gloss is (60 ° gloss system) characterized in that 10 to 30% Method for producing high weathering semi-gloss powder coating.