JPH02178360A - Powder coating - Google Patents

Abstract

PURPOSE:To obtain a powder coating having excellent blocking resistance and giving a coating film having excellent appearance by compounding non crosslinked resin particles having a glass transition temperature falling within a specific range. CONSTITUTION:The objective coating material contains preferably 0.05-35wt.% of fine particles of a non-crosslinked resin having a glass transition temperature (Tg) of 50-150 deg.C (preferably 70-120 deg.C) and an average particle diameter of preferably 0.001-10mum.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a powder coating, and more particularly to a powder coating that has excellent anti-blocking properties and can provide a high-appearance coating.

Conventional technology Powder coatings have long been required to have both flowability and anti-blocking properties. Here, blocking resistance refers to resistance to so-called blocking, which occurs when particles fuse together or form a hard cake when a sample is stored at room temperature, and is related to storage stability. After electrostatic coating or fluid dip coating, baking 1: The powder melts and flows onto a smooth surface when it evaporates, which is sufficient to form a smooth coating without pinholes or pockmarks. Liquidity is required.

Since 1999, attempts have been made to lower the molecular weight of the binder resin used in the powder and to lower the glass transition temperature (T g ) in order to ensure this flowability. Blocking resistance decreases, film physical properties worsen, etc. At present, ffe is trying to balance these, focusing on basic performance, flowability and blocking resistance, and combining physical properties with 1) 1-liquid design. Paint it
This is the design philosophy. After 6 days of use, the appearance of the paint film due to its flowability was inferior to that of ordinary solvent-based paints in terms of smoothness. In order to remove it, the manufacturer [7
In addition, in terms of anti-blocking properties, it is difficult to say that Otsukan and Sushi are high-performance, and there are problems with long-term stability for more than 6 months and storage stability in the summer. The man-hours and costs associated with storage and transportation are also high.

Therefore, to deal with these problems, it is recommended to add inorganic particles such as colloidal silica and siloxane to the powdered wood coating T4. Appearance defects such as loss of gloss in the paint film may result.
In addition, since it had a negative effect on water resistance, the amount used was only about 0.2% at most, which was extremely insufficient in terms of improvement in professional and soaking resistance. Therefore, cross-linked resin particles with an average particle size of 0.01 to 10μ are added to the 1'1 of the costume coat,
A technique for improving blocking resistance, weather resistance, and hardness has been proposed by the present applicant (Japanese Patent Application Laid-open No. 02292869) and is attracting attention in the industry. According to this technology, the blocking resistance of the powder coating f1 is greatly improved, and the weather resistance and hardness of the coating film are significantly improved, but since the fine particles are crosslinked particles, they do not flow by themselves, and - There is a need for powder wood coating 1':) that can provide a coating film with excellent coating properties on the outside E1 and has excellent flow properties.

Problems to be solved by the invention Therefore, it is possible to better balance the conflicting phenomena of coated ILi outer cut and blocking resistance, and in particular, to improve
It is an object of the present invention to provide a powdered wooden knife that can give a lfffi+ pattern.

Means for Solving the Problems In the present invention, b'C, the object of the invention is to solve the glass transition temperature (T
g) non-framed li at 50°C to 150°C? This can be achieved by applying 1 coat for 1 minute containing fat-disintegrating fine particles.

Since the resin particles used in the present invention flow when heated, their Tg is within a specific range, that is, 50°C to 150°C, more preferably 70°C to 120°C.
These are non-crosslinked resin fine particles within the temperature range of ℃. The present inventors have developed powder-coated Ti powder whose average particle size is usually in the range of 30 to 50 mm.
Fine particles added to the powder particles f for the purpose of improving blocking resistance; n As a result of various studies on machining, non-crosslinked resin fine particles having a Tg higher than the peeling fat 1 constituting the powder particles described above were added. By allowing at least some of the powder particles to exist on the surface, even if the powders come into contact with each other during storage, the fine resin particles will fuse together at room temperature, making it easy to use! It does not cause kinging, but rather improves the smoothness and fluidity of the powder.Also, since it is a non-crosslinked ()1 resin fine particle, when heat is applied during the flow of the powder coating, this resin fine particle It was discovered that powder coatings which flow by themselves, have a particularly excellent appearance, and have a particularly good external M1 and blocking resistance, and this is the basis of the present invention.

(1) The resin particles can be composed of high-quality resins used in the paint field, but from the viewpoint of production or practical use, vinyl (resin (including acrylic resin), epoxy resin, polyester resin, melamine (51) Preferably, vinyl resins are preferred from the viewpoint of ease of manufacture and freedom of design. Must be within the range.

This is because if the Tg is less than 50°C, it will be difficult to ensure sufficient blocking resistance of the powder coating during storage and transportation, and if the Tg exceeds 150°C, it will not be very practical. It is from.

As long as the average particle size of one resin particle is smaller than the powder diameter, it is not very strict.No need for 5g, usually 1),
1 JO 1 to 10 μ, preferably within the range of 0.01 to 5 μ
(middle) 5 to 35% by weight, preferably about 0.1 to 1026%. This is for the purpose of the present invention) 1) The average particle size of the resin fine particles and the amount added are in a proportional amount 1 system, and the lower limit of the particle size is approximately Q,001 due to the ease of industrial production of the resin fine particles.
In that case, the effect of particle addition is 0.
．． If the particle size exceeds 10μ, a large amount of particles will be required to give the coating resistance of 1.0% by weight, which may adversely affect the appearance of the coating film. This is based on the knowledge that there is a tendency for

The method for producing +31 fat particles is not limited in any way; for example, the above-mentioned particles can be directly produced using milk, suspension, etc.
(1) fat can be obtained by making a resin with Y, solution weight, lump weight, etc., crushing it, and classifying it.

In the present invention, the above-mentioned 1+51 fat particles are added to ordinary powder particles for powder coating 1, and are made to exist at least on the surface thereof.

Powder particles for powder coatings include, for example, a binder resin that is solid at room temperature and has film-forming properties such as vinyl resin, polyester resin, and epoxy resin, as well as pigments and hard resins. and additives added as desired, and are usually granulated to have an average particle size of about 30 to 50 microns. There is also a clear field that does not contain pigments. In this way, the powder particles normally used as the powder coating L1 can be advantageously used, but in the present invention, it is possible to apply a powder with a low Tg, such as 40'C, which could not be used once because it would cause blocking during future storage. low to the extent
I゛g F3 (It has been confirmed that powder coatings based on fat may also be used.) In the present invention, such powder particles are coated with the above-mentioned resin particles. It can be added at any step of the powder particle production process as long as it is present on the surface.

However, in order to maintain the individual shape of the resin fine particles and to ensure that they are present on the surface of the powder particles, it is preferable to add resin particles to the powder particles. For example, powder raw material (A
Fat, face 1'-1, i, 'f: A method of adding additives, melting and kneading, and then mixing them with l; Powder particles are made by wet dispersion from Powder Kihara f-],
Before or after drying? A method of adding fine resin particles to 37& and mixing with a mixer; A method of mixing powder particles obtained by melt-kneading or wet dispersion with fine resin particles using a hybridizer ball mill, etc., and driving the fine resin particles onto the surface of the powder particles; Examples include a method in which body particles are coated with resin fine particles and formed into a continuous film.B. In the present invention, the term "3" for resin fine particles includes any of the above embodiments. However, the present invention is not limited in any way by these manufacturing methods; for example, a relatively large amount of resin fine particles having a relatively high Tg is used in the powder melting and granulation process, and the resin fine particles are made to exist at least on the surface of the powder particles. Of course, it is also possible to use a combination of these methods. Regardless of which method is used, the powder coating of the present invention has a glass transition temperature within a specific range and is a resin that exhibits flowability when heated. Provided as a powder coating in which fine particles are present at least on the surface of the powder, it has excellent blocking resistance, can withstand long-term storage, storage in high humidity areas, and transportation, and has an especially excellent appearance when baked. This powder coating is industrially extremely useful as it can provide a coating film with a high temperature.The present invention will be explained below with reference to Examples.

Parts and percentages are by weight unless otherwise specified.

- (Synthesis of non-crosslinked resin particles) Add 3 liters of deionized exchanged water to a reaction vessel equipped with a stirrer, cooler, and temperature controller.
80 parts of nonionic surfactant MON2 (manufactured by Sanyo Chemical Co., Ltd.) were charged, dissolved while maintaining the stirring temperature at 80°C, and initiator: 1 part of ammonium persulfate was added to 1 part of deionized exchange water. Add the dissolved liquid.

Then, a mixed solution consisting of 19 parts of 2-hydroxyethyl methacrylate, 20 parts of styrene, and 61 parts of n-butyl methacrylate was added dropwise over a period of 60 minutes.

After dropping, continue stirring at 80°C for 60 minutes. In this way, an emulsion with a nonvolatile content of 20% and a particle size of 0.03 to 0.05 μm is obtained. Spray dry this emulsion and make 7g
40°C, resin fine particles A with an average particle size of 0.03 to 0.05μ
-1 was obtained.

Part 1: Possible 3- (Synthesis of non-crosslinked resin fine particles) In a reaction vessel equipped with a stirrer, a cooler, and a temperature controller, add deionized exchange water 3
80 parts of nonionic surfactant MON2 (manufactured by Sanyo Chemical Co., Ltd.) were charged and dissolved while maintaining the stirring temperature at 80°C, and 1 part of ammonium persulfate (initiator) was dissolved in 10 parts of deionized exchange water. Add the solution.

Then 85 parts of methyl methacrylate, 5 parts of styrene, n
- 60 parts of a mixed solution consisting of 10 parts of butyl methacrylate
It takes a few minutes to drip. After dropping, continue stirring at 80°C for 60 minutes. In this way, the nonvolatile content is 20%, the particle size is 0.03~
A 0.05μ emulsion is obtained.

This emulsion was spray-dried to obtain resin fine particles A-2 having a Tg of 100oC.

11 Good 1 (Synthesis of non-crosslinked resin fine particles) In a reaction vessel equipped with a stirrer, a cooler, and a temperature controller, 380 parts of deionized exchanged water and a nonionic surfactant MON2 were added.
(manufactured by Sanyo Chemical Co., Ltd.), dissolved while maintaining the stirring temperature at 80℃, and added initiator: ammonium persulfate 1 part
1 part dissolved in 10 parts deionized exchanged water is added.

Then, a mixed solution consisting of 85 parts of methyl methacrylate and 5 parts of styrene was added dropwise over a period of 60 minutes.

After dropping, continue stirring at 80°C for 60 minutes. In this way, an emulsion with a nonvolatile content of 20% and a particle size of 0.3 μm is obtained. This emulsion was spray-dried to obtain fine resin particles A-3 having a Tg of 10 OoC.

LtL! IL (synthesis of non-crosslinked resin particles) Deionized exchanged water (38 cm) was placed in a reaction vessel equipped with a stirrer, a cooler, and a temperature controller.
0 parts of nonionic surfactant MON2 (manufactured by Sanyo Chemical Co., Ltd.) were charged and dissolved while maintaining the stirring temperature at 80°C, and initiator: 1 part of ammonium persulfate was dissolved in 10 parts of deionized exchange water. Add the solution.

Next, 61 parts of methyl methacrylate, 36 parts of styrene,
60% of a mixed solution consisting of 3 parts of n-butyl methacrylate
It takes a few minutes to drip. After dropping, continue stirring at 80°C for 60 minutes. In this way, the non-volatile content is 20% and the particle size is 0.03.
An emulsion of ~0.05μ is obtained. This emulsion was spray-dried to obtain resin fine particles A-4 with Tgl10.

Quan Yen 1 Sudden - (Preparation of pulverized non-crosslinked particles) Reference Example 1 described below
7 g and 90 of the acrylic resin A-11 synthesized in Step 1 were crushed into fine particles using a pulverizer until the average particle size was about 15 μm to obtain non-crosslinked resin particles A-5.

11 [<Preparation of pulverized non-crosslinked particles] 7g90 acrylic resin A synthesized in Reference Example 11 described below
-11 was pulverized to an average particle size of approximately 0.5 μm using a pulverizer to obtain non-crosslinked resin fine particles A-6.

1-(Preparation of crushed non-crosslinked particles) Epoxy resin Y
D-019 <@Tobu Kasei Co., Ltd.) was crushed to an average particle size of 0 using a crusher.
, to obtain non-crosslinked resin particles A-7.

3-(Synthesis of cross-linked resin fine particles) Add 28 mL of deionized exchanged water to a reaction vessel equipped with a stirrer, cooler, and temperature controller.
2 parts of nonionic surfactant MON2 (manufactured by Sanyo Chemical Co., Ltd.) and dimethylethanolamine were charged and dissolved while maintaining the stirring temperature at 80°C, and the initiator:
A solution prepared by dissolving 4.5 parts of azobiscyanovaleric acid in 45 parts of deionized exchange water and 4.3 parts of dimethylethanolamine is added. Next, 70.7 parts of styrene, 94.2 parts of n-butyl acrylate, 70.7 parts of methyl methacrylate,
A mixed solution consisting of 30 parts of 2-hydroxyethyl acrylate and 4.5 parts of ethylene glycol dimethyl methacrylate is added dropwise over 60 minutes. After dropping, 1.5 parts of azobiscyanovaleric acid was dissolved in 15 parts of deionized water and 1.4 parts of dimethylethanolamine.
Continue stirring at 80°C for 60 minutes. Thus the non-volatile content 4
An emulsion with a particle size of 5% and a particle size of 0.16μ is obtained. This emulsion was spray-dried to obtain resin fine particles A-8.

Pot] outside 9 (TG70G70 acrylic) dropping funnel,
80 parts by weight of xylene was charged into a flask equipped with a stirring blade and a thermometer and heated to 130°C.

Using a dropping funnel, add 55 parts of methyl methacrylate, 10 parts of styrene, 30 parts of glycidyl methacrylate, n-
A solution of 5 parts of butyl methacrylate and 0.6 parts of Kaya ester as an initiator was dropped into the above flask at a uniform rate over 3 hours. After completion of the 0 drop f & held for 30 minutes, 20 parts of xylene and 0.1 part of Kaya ester were added using a dropping funnel over 1 hour. It was dropped at a uniform rate.

After the dropwise addition was completed, the mixture was further maintained at 130° C. for 2 hours, and then xylene was removed by vacuum distillation to obtain Ta2O and acrylic resin A-9.

111 (Synthesis of TG40 acrylic) 80 parts by weight of xylene was charged into a flask equipped with a dropping funnel, a stirring blade, and a thermometer, and heated to 130°C.

Using a dropping funnel, add 19 parts of methyl methacrylate, 10 parts of styrene, 30 parts of glycidyl methacrylate, n-
Butyl methacrylate 41 parts, initiator Kayaester 06
A portion of the solution was added dropwise to the flask at a uniform rate over 3 hours. After the dropwise addition was completed, the mixture was held for 30 minutes, and then 20 parts of xylene and 01 parts of Kayaester were added dropwise at a constant rate over 1 hour using a dropping funnel.

After the dropwise addition was completed, the mixture was further maintained at 130°C for 2 hours, and xylene was removed by vacuum distillation to obtain acrylic resin A-10.

11 Takumi 11 (Synthesis of TG90 acrylic) 80 parts by weight of xylene was charged into a flask equipped with a dropping funnel, a stirring blade, and a thermometer, and heated to 130°C. Using a dropping funnel, add 36 parts of methyl methacrylate, 10 parts of styrene, 24 parts of glycidyl methacrylate, and 24 parts of n-butyl methacrylate.
A solution containing 30 parts of tertiary butyl methacrylate and 06 parts of initiator Kayaester was added dropwise to the above flask at a constant rate over 3 hours. After dropping, hold for 30 minutes, add xylene 2
0 parts of Kayaester and 01 parts of Kayaester were added dropwise at a uniform rate over 1 hour using a dropping funnel. After the dropwise addition was completed, the mixture was further maintained at 130°C for 2 hours, and then xylene was removed by vacuum distillation to obtain acrylic resin A-11.

m2 L3 (TG70G70 acrylic paint) 100 parts by weight of acrylic resin A-9 of Reference Example 9, 24 parts of decane dicarboxylic acid, and 30 parts of acid f-hititane CR5 were dry mixed in a Henschel mixer (manufactured by Mitsui Miike Seisakusho Co., Ltd.), and then mixed in a co-kneader. PR-46 (Switzerland: 100℃ manufactured by Buss)
Melt and disperse at a temperature of
Powder particles were obtained by classification using a 50-mesh wire mesh. To this, 1.54 parts of resin fine particles A-6 (1% based on the base powder paint ratio)
) and dry mixed for 30 seconds using a Henschel mixer to obtain powder particles A-12.

1 13 (Preparation of polyester paint) 100 parts by weight of ER6800 (polyester resin manufactured by Nippon Polyester Co., Ltd.), 36 parts of Fulleran UI (blocked isocyanate manufactured by BASF), and 40 parts of titanium oxide CR500 were mixed in a Henschel mixer (manufactured by Mitsui Miike Seisakusho Co., Ltd.). The mixture was dry mixed, then melted and dispersed at a temperature of 100°C in a co-kneader PR-46 (manufactured by Buss, Switzerland), and after cooling, it was crushed in a hammer mill and classified with a 150-mesh wire mesh to obtain powder particles A-13. Obtained.

Committee' LVA engineering (preparation of epoxy paint) Epoto) Y
100 parts by weight of D-019 (epoxy resin manufactured by Tobu Kasei Co., Ltd.), 3 parts of dicyandiamide, and 40 parts of acid f-hititanium CR50 were dry mixed in a Henschel mixer (manufactured by Mitsui Miike Manufacturing Co., Ltd.), and then co-kneader PR-46 (Switzerland: Buss Co., Ltd.). After cooling, the mixture was melted and dispersed at a temperature of 100° C., and after cooling, it was crushed in a hammer mill and classified using a 150-mesh wire mesh to obtain powder particles. 1.46 parts of resin fine particles A-2 (1% based on the base paint ratio) were added and dry mixed for 30 seconds in a Henschel mixer to obtain powder paint A-14, 6111LΣ(T
Preparation of G40 acrylic paint) 100 parts by weight of the acrylic resin A-10 of Reference Example 10 and 24 parts of decanedicarboxylic acid were dry mixed in a Henschel mixer (manufactured by Mitsui Miike Seisakusho Co., Ltd.), and then mixed with Cokneader PR-46 (manufactured by Buss AG, Switzerland). )
After cooling, the mixture was melted and dispersed at a temperature of 100°C, then crushed in a hammer mill, and classified using a 150-mesh wire mesh to obtain powder particles A.
-15 was obtained.

#<Non-crosslinked resin fine particles A-21% addition) 1 part of resin fine particles A-2 was added to 100 parts of powder particles A-12 obtained in Reference Example 12.
(1% based on the base powder paint ratio) and dry mixed for 30 seconds in a Henschel mixer to obtain a powder paint.

Table 1 shows the evaluation of the appearance and blocking of the powder coating material prepared in this way, and good results were obtained in both cases.

Ratio J [Fine] - (Addition of 11% of non-crosslinked resin fine particles A) A powder coating was obtained in the same manner as in Example 1, except that the type of resin fine particles was changed to A-1.

The appearance and blocking evaluation of the resulting powder coating are shown in Table 1, and the blocking was poor.

A powder coating material was obtained in the same manner as in Example 1 except that the type of resin particles was A-3.

Table 1 shows the evaluation of the appearance and blocking of the thus produced powder coating, and good results were obtained in both cases.

Comparison 1 Seishi Tae (non-crosslinked resin fine particles A-51% addition) Same as Example 1 except that the type of fine particles was A-5,
A powder coating was obtained.

Table 1 shows the evaluation of the appearance and blocking of the resulting powder coating, and poor results were obtained in both cases.

! (Addition of 20% of non-crosslinked resin particles A-3) 20 parts of resin particles A-3 (20% relative to the base powder coating) were added to 12,100 parts of the powder particles A-12 obtained in Reference Example 12, and the mixture was heated in a Henschel mixer. Dry mixing was performed for 30 seconds to obtain a powder coating.

Table 1 shows the evaluation of the appearance and blocking of the powder coating thus produced, and good results were obtained for both.

Example 3 except that the amount of resin fine particles A-4 added was 0.01 part (0.01% relative to the base powder coating) Similarly,
A powder coating was obtained.

The appearance and blocking evaluation of the powder coating thus produced are shown in Table 1, and poor blocking results were obtained.

Ratio U (addition of 40% of non-crosslinked resin particles A-4) A powder coating was prepared in the same manner as in Example 3, except that the amount of resin particles A-4 added was 40 parts (40% relative to the base powder coating). Obtained.

The appearance and blocking evaluation of the powder coating thus produced are shown in Table 1, and the results show that the appearance is poor.

Ratio ff1 (addition of 0% non-crosslinked resin fine particles) Powder paint was obtained in the same manner as in Example 3 except that no amount of resin fine particles was used. Evaluation of appearance and blocking of the resulting powder paint. are listed in Table 1, but poor blocking results were obtained.

Fruit myu (non-crosslinked resin fine particles A-21% added/polyester powder) 1 part of resin fine particles A-2 was added to 100 parts of powder particles A-13 obtained in Reference Example 13 (1% based on the base powder paint ratio). In addition, dry mixing was performed for 30 seconds using a Henschel mixer to obtain a powder coating.

Table 1 shows the evaluation of the appearance and blocking of the powder coating thus produced, and good results were obtained for both.

E1random i<Non-crosslinked resin fine particles A-21% addition/epoxy powder) To 100 parts of powder particles A-14 obtained in Reference Example 14, 1 part of resin fine particles A-2 (1% in terms of base powder particle ratio) ) and dry mixed for 30 seconds using a Henschel mixer to obtain a powder coating.

Table 1 shows the evaluation of the appearance and blocking of the powder coating thus produced, and good results were obtained for both.

x] 1 inhibition (addition of 61% of non-crosslinked pulverized resin particles A) To 100 parts of powder particles A-12 obtained in Reference Example 12, 1 part of resin particles A-6 was added (1% based on the base powder coating ratio) ) and dry mixed for 30 seconds using a Henschel mixer to obtain a powder coating.

Table 1 shows the evaluation of the appearance and blocking of the powder coating thus produced, and good results were obtained for both.

E1 Takumi L<Non-crosslinked pulverized resin fine particles A-71% addition) To 100 parts of powder particles A-12 obtained in Reference Example 12, 1 part of resin fine particles A-7 (1% based on the base powder paint ratio) was added. The mixture was dry mixed for 30 seconds using a Henschel mixer to obtain a powder coating.

Table 1 shows the appearance and blocking evaluation of the powder coating obtained in this way, and good results were obtained for both.

Ratio ff1 (addition of 20% of cross-linked resin fine particles A-8) Addition amount of resin fine particles A-8 is 20 parts (20% relative to base powder coating)
A powder coating material was obtained in the same manner as in Example 6 except for the following.

The appearance and blocking evaluation of the powder coating thus prepared are shown in Table 1, and the results show that the appearance was poor.

16Jffi (Non-crosslinked resin fine particles A-25% addition/T
G40 powder) To 100 parts of powder particles A-15 obtained in Reference Example 15, 5 parts of resin fine particles A-2 (5% based on the base powder coating ratio) were added and dry mixed for 30 seconds in a Henschel mixer to form a powder. Got the paint.

Table 1 shows the evaluation of the appearance and blocking of the thus produced powder coating, and good results were obtained in both cases.

Ratio Jli (Addition of 0% non-crosslinked resin particles/TG40 powder) Powder particles were obtained in the same manner as in Example 8, except that no resin fine particles were used.

Table 1 shows the evaluation of the appearance and blocking properties of the powder paint thus produced, and good results were obtained for both.

Roasted-1 Test method 1) Blocking property test Powder paint was heated to 40°C.
Evaluate the fluidity of powder coating after storage.

[Evaluation method] ○: There are no lumps and the fluidity is very good.

△゛There are some lumps, but they loosen up quickly It will be done.

×: There is a lump that cannot be separated.

2) Paint film appearance ○: Good △; Gloss is slightly reduced, A few rounds occur ×: Poor (almost no shine, (Many rounds) patent application agent

Claims (2)

[Claims] (1) A powder coating containing non-crosslinked resin fine particles having a glass transition temperature (Tg) of 50°C to 150°C. (2) The average particle size of non-crosslinked resin fine particles is 0.001 to 10
μ, and its content is 0.0 of the total powder coating in terms of solid content weight ratio.
The powder coating according to claim 1, wherein the amount is 5 to 35% by weight.