JP3315712B2 - Composition for paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition.

[0002]

2. Description of the Related Art Metal plates coated with a fluororesin paint are made of aluminum, zinc-iron, aluminum, etc. because of their excellent physical and chemical properties, such as excellent weather resistance, chemical resistance, and corrosion resistance. -Widely used in building materials such as roofs and walls as metal plates with excellent durability such as zinc alloy steel plates and stainless steel plates. In addition, fluororesin paint can be relatively expensive, can be applied to a thin thickness, and,
Coating is being carried out using a method that reduces paint loss.

[0003] For example, after a metal plate is continuously coated with a roll coat, a flow coat, or the like, the metal plate is cut and formed into a required size and shape and then provided to a roof or a wall. is there. In such a case, at the time of painting, at the time of molding processing, the coating film is damaged by friction, impact or scratching, or when it is cracked by bending, the appearance and durability are reduced, and the commercial value is impaired. . Also, as the fluororesin paint used in such a coating method, a paint mainly composed of vinylidene fluoride resin is famous, but it is difficult to recoat such as touch-up and repair, and the color tone and gloss are limited. It has practical disadvantages.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide characteristics required for a fluororesin paint, such as excellent weather resistance, chemical resistance, corrosion resistance, scratch resistance, and workability such as bending. Further, the present invention provides a coating composition having improved practical properties such as recoatability, design properties such as color tone and gloss.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is directed to a solvent-soluble fluororesin having a reactive group obtained by copolymerizing a fluoroolefin and a hydrocarbon monomer ( X) and a solvent-soluble fluororesin (Y) having a reactive group obtained by copolymerizing a fluoroolefin and a hydrocarbon monomer (excluding the above (X))
A coating composition containing 1/5 to 5/1 in weight ratio (provided that “15 to 70% by weight of a fluoroolefin that may or may not contain vinylidene fluoride, A fluoroolefin copolymer (A) obtained by copolymerizing 85 to 30% by weight of another vinyl monomer copolymerizable with a fluoroolefin, and a fluoroolefin having vinylidene fluoride as an essential monomer component. A fluoroolefin copolymer (B) containing at least 80% by weight of an olefin as an essential component, and a solid weight ratio (A) / (B) of the copolymer (A) and the copolymer (B). Is 50
/ 50 to 99.9 / 0.1 ". ) And (X)
The glass transition temperature T _g of the uncured, glass transition of (Y)
An object of the present invention is to provide a coating composition characterized in that the transfer temperature _Tg is 5 ° C. or lower and the elongation of (X) is 10% or more higher than the elongation of (Y). The preferred embodiments of the present invention are as follows.

[0006] The above coating composition, wherein the elongation percentage of (X) is 20% or more. The above-mentioned coating composition, wherein the elongation percentage of (X) is 30% or more. The elongation of the mixture of (X) and (Y) is (Y)
The above coating composition having an elongation of at least 5%.

The glass transition temperature T _{g of the} uncured state of ( X)
Is 10 _% higher than the glass transition temperature T _{g of the} uncured state of (Y).
The above-mentioned coating composition for which the temperature is lower than or equal to ° C. The above coating composition, wherein the glass transition temperature T _g ′ of the cured coating film based on (Y) is 40 ° C. or more. The above coating composition, wherein the cured coating film based on (X) and (Y) has a glass transition temperature T _g ′ of 30 ° C. or more.

The weight ratio of ( X) and (Y) is 1/3 to 3/1
The above-mentioned composition for a coating composition containing at a ratio of:

The above-mentioned coating composition containing (X) and (Y) and further a coloring agent (C). (C) The above-mentioned coating composition, wherein the composition is a pigment or a dye. The above-mentioned coating composition obtained by mixing (X) and (C) first, and then mixing (Y). The above-mentioned coating composition obtained by mixing (X) and (Y) first, and then mixing (C). The above-mentioned coating composition comprising (X) and (Y) and further containing a curing agent (D). The above-mentioned coating composition, wherein (D) is a polyvalent isocyanate-based curing agent or a block polyvalent isocyanate-based curing agent.

[0010] A coating method in which the coating composition is applied and forcedly dried. The above-mentioned coating method, wherein the forced drying temperature is _{equal to} or higher than the glass transition temperature Tg of the uncured state (Y). The above coating method, wherein the forced drying temperature is a temperature not _lower than the flow start temperature _Tf of (Y).

The terms used in this specification are defined as follows. Elongation: at 30 ° C, J
Value (%) measured according to ISK-5400. Glass transition temperature T _g : Rigid pendulum type viscometer DDV-OPA
The temperature (° C.) at which the transition starts (the glass transition temperature T _g ′ of the cured coating film is determined by using the curing agent Coronate EH (manufactured by Nippon Polyurethane Industry Co., Ltd.) at a ratio of OH / NCO = 1.0. This is a value measured for a cured coating film obtained by drying and curing at 120 ° C. for 20 minutes). Flow start temperature T _f : measured using the above, temperature at which flow starts (° C.).

The (X) of the present invention has a high degree of weather resistance,
A solvent-soluble fluororesin having a reactive group obtained by copolymerizing a fluoroolefin having chemical resistance and corrosion resistance and a hydrocarbon monomer is employed.

That is, (X) is a copolymer of a fluoroolefin and a hydrocarbon monomer such as vinyl ether or vinyl ester, and is a copolymer of a hydroxyl group, a carboxylic acid group, a hydrolyzable silyl group and an epoxy group. A fluorine-containing copolymer having a functional group is employed. Specific examples of (X) include copolymers of chlorotrifluoroethylene, cyclohexyl vinyl ether, alkyl vinyl ether, hydroxyalkyl vinyl ether, and copolymers of chlorotrifluoroethylene, alkyl vinyl ether, and allyl alcohol. These are commercially available under the names of Lumiflon (manufactured by Asahi Glass Co., Ltd.) and Sefral Coat (manufactured by Central Glass Co., Ltd.). For example, Lumiflon LF-550, LF-552, LF-554, LF-6
00, LF-601, LF-602 and the like.

As (Y) in the present invention, a solvent-soluble fluororesin having a reactive group obtained by copolymerizing a fluoroolefin and a hydrocarbon monomer is employed. That is, a copolymer of a fluoroolefin and a vinyl monomer, a hydrocarbon monomer such as a vinyl ester, a hydroxyl group,
A fluorine-containing copolymer having a reactive group such as a carboxylic acid group, a hydrolyzable silyl group, and an epoxy group is used.
Specific examples of (Y) include copolymers of chlorotrifluoroethylene, cyclohexyl vinyl ether, alkyl vinyl ether, hydroxyalkyl vinyl ether, and copolymers of chlorotrifluoroethylene, alkyl vinyl ether, and allyl alcohol. These are commercially available under the names of Lumiflon (manufactured by Asahi Glass Co., Ltd.) and Sefral Coat (manufactured by Central Glass Co., Ltd.). For example, Lumiflon LF-100, LF-200, LF-3
02, LF-400, LF-700, LF-916, L
F-936 and the like.

[0015] The coating composition of the present invention comprises (X)
In addition to (Y), various components can be contained as needed. Usually, the coloring agent (C) is used as a coloring component, but the coloring component may not be used.

The coloring agent (C) may be either a pigment or a dye. For example, titanium oxide, zinc white,
Carbon black, iron black, copper chrome black, copper iron manganese black, red iron oxide, zinc iron brown, cadmium red, chrome vermillion, graphite, cadmium yellow, zinc chromate, cobalt green, chrome green, chrome oxide green, titanium Nickel, cobalt, zinc based green, pyridian, cobalt green, cobalt
Inorganic pigments such as chrome green, navy blue, ultramarine, cobalt blue, cobalt violet, manganese violet, white carbon, silica white, alumina white, gypsum, precipitated barium sulfate, precipitated barium carbonate, etc.,
β-naphthol, β-oxynaphthoic acid, naphthol NAS, pyrazolone, acetoacetate, acetoacetate anilide, phthalocyanine, anthraquinone, indigo, perylene, perinone, dioxazine, quinacridone, Organic pigments such as isoindoline-based, metal complex-based, fluorpine-based, and quinophthalone-based pigments, white pigments, black pigments, red pigments, yellow pigments, green pigments, and blue pigments can be used. Also, aluminum powder, gold powder, silver powder, copper powder, brass powder, flaky mica treated with titanium oxide and the like can be used.

Further, as various components, a curing agent (D), resins, solvents, viscosity modifiers, dispersants, defoamers,
Anti-segregation agent, ultraviolet absorber, antioxidant, light stabilizer,
Known and commonly used ones such as coupling agents can also be used.

Among such components, as the curing agent (D), those known as curing agents for paints can be used. Specific examples include melamine-based curing agents such as aminoplast resins and urea resins, amino-based curing agents, polyvalent isocyanate-based curing agents, and block polyvalent isocyanate-based curing agents. When the coating composition of the present invention is used in applications that are processed after application of a precoated metal or the like, a polyvalent isocyanate-based curing agent and a block polyvalent isocyanate-based curing agent are preferably used. Commercially available polyvalent isocyanate-based curing agents or block polyvalent isocyanate-based curing agents include Vernock D-750, Vernock D-800, Vernock DN-950, Vernock D
N-960, Takenate-D-102, Takenate-D
N-110N, Takenate-D-140N, Takenate-B-842, Coronate EH, Coronate L, Coronate HL, Coronate 2030, Coronate 2527,
There are death module L, death module N, death module HL, and the like.

The usual method can be employed for mixing (X) and (Y) with various components such as the colorant (C). For example, (X),
A method of simultaneously mixing (Y) and various components such as colorant (C), a method of mixing (X) and various components such as colorant (C) and then mixing (Y), a method of mixing (Y) and colorant The method of blending (X) after blending various components such as (C), the blending of (X) blending necessary components such as colorant (C) and the necessary components such as colorant (C), and (Y) ) Are mixed.

In the present invention, in order to exhibit a better effect, a method of simultaneously mixing (X), (Y) and various components such as a colorant (C), a method of mixing (X) and a colorant (C), etc. (X) in which necessary components such as a colorant (C) and the like are blended, and a colorant (C).
Such as a method of mixing with (Y) in which necessary components such as
It is preferable to mix various components in the presence of the component (X).

The coating composition of the present invention is preferably in the form of a solution dissolved in an appropriate solvent from the viewpoint of coatability. Here, as the solvent, the above (X) and (Y)
Is not particularly limited as long as it can dissolve the compound, and can be appropriately selected in consideration of workability and the like. Any solvent commonly used as a solvent for paints can be used in the composition of the present invention. In particular, aromatic solvents such as toluene and xylene are preferable.

The coating composition of the present invention can be used for spray coating, brush coating, roll coater, flow coater,
The metal plate can be coated by a known and commonly used method such as a bar coater. As such a metal plate, an aluminum plate,
Examples include a zinc iron plate, an aluminum-zinc alloy steel plate, and a stainless steel plate. Of course, the metal plate can be painted even if it has been subjected to a physical or chemical treatment such as a plast treatment, a chemical treatment, a primer treatment, or a combination thereof, and may be preferable in terms of durability.

When the composition of the present invention is applied, it is preferable to perform forced drying. Even when curing can be performed at room temperature using a polyvalent isocyanate-based curing agent or the like as the curing agent (D), forced drying is preferable. By forcible drying, bending workability and the like are further improved. Here, the forced drying temperature depends on conditions such as the drying time, but is usually a temperature equal to or higher than the glass transition temperature T _g of the uncured (Y) state, and preferably the flow start temperature T _f of (Y). The above temperatures are employed.

[0024]

In the present invention , ( X) functions so as not to cause cracks in the coating film during the forming process such as bending due to its softness, while ( Y) functions due to its hardness due to its hardness. It is considered to improve resistance to scratches caused by friction and impact on the coating film during processing and scratches. Also,
Since it is a solvent-soluble fluororesin, it can provide excellent weather resistance, chemical resistance, corrosion resistance, recoating property, color tone, gloss and the like. When a resin having contradictory properties is mixed with a resin having flexibility and a resin having hardness,
It is usually an intermediate property, and it is customary that the resistance to cracking and the resistance to scratches are also between the two, and it is not clear why the intermediate properties are not exhibited and the advantages of both are exhibited as in the present invention. However, it is estimated as follows.

( X) and ( Y) have a micro-sea-island structure at the time of forming the coating film, and (X) has flexibility as an island portion against external force such as bending, but relaxes the stress and reduces the stress, It is presumed that (Y) having hardness, which is a sea portion, resists an external force that causes scratches on the surface. A compounding method that easily forms a micro-sea-island structure like this, for example,
A method of simultaneously mixing (X), (Y) and various components,
In the presence of (X), a method of blending (X) and various components and then blending (Y), a method of blending (X) blending the necessary components and (Y) blending the necessary components, and the like This is presumed from the fact that the effects of the present invention are easily exerted when various components are blended. However, such estimation does not limit the present invention.

[0026]

EXAMPLES Example 1 A composition having the following composition was dispersed to obtain a coating (a) containing the component ( X). (1) 70 parts by weight of a fluorinated copolymer composed of chlorotrifluoroethylene, ethyl vinyl ether and hydroxybutyl vinyl ether (trade name: Lumiflon LF-600 , manufactured by Asahi Glass Co., Ltd.) (2) 20 parts by weight of titanium oxide (3) methyl Isobutyl ketone 10 parts by weight Lumiflon LF-600 is a xylene solution (solid content 50%) of a fluororesin having an uncured glass transition temperature of 25 ° C. and an elongation of 80% or more. Hereinafter, it is abbreviated as LF-600.

Further, a composition having the following composition was dispersed to obtain a paint (b) containing the component ( Y). (1) 60 parts by weight of a fluorinated copolymer comprising chlorotrifluoroethylene, ethyl vinyl ether, cyclohexyl vinyl ether and hydroxybutyl vinyl ether (trade name: Lumiflon LF-200 , manufactured by Asahi Glass Co., Ltd.) (2) 20 parts by weight of titanium oxide (3) ) Methyl isobutyl ketone 20 parts by weight Lumiflon LF-200 has an uncured glass transition temperature of 35 ° C, an elongation of 5% or less, a glass transition temperature of a cured coating film of 45 ° C, and a flow start temperature of 60 ° C. Xylene solution of fluororesin (solid content 60%). Hereinafter, LF-200
Abbreviated.

The mixture of LF-600 and LF-200 has an elongation of 50%, and the glass transition temperature of the cured coating film is 42%.
° C.

50 parts by weight of paint (a), 50 parts by weight of paint (b), and hexamethylene diisocyanate as a curing agent
Polyisocyanate-based curing agent that is
Name: Coronate EH , Nippon Polyurethane Industry Co., Ltd. 8 parts by weight, dibutyltin dilaurate (1% xylene solution)
0.5 parts by weight was mixed and stirred. This was coated on an aluminum plate to which an epoxy-based rust-preventive primer had been applied by a bar coater so as to have a dry coating thickness of 30 μm, and dried at room temperature to obtain a fluorine-painted aluminum plate. The T-bend test result of this fluorine paint-coated aluminum plate is 0T
And the result of the pencil hardness test was 2H.

Examples 2 and 3 and Comparative Examples 1 to 4 Fluorine paint-coated aluminum plates were obtained in the same manner as in Example 1 except that the mixing ratio of paint (a) and paint (b) in Example 1 was changed. Table 1 shows the results of the T-fold test and the pencil hardness test.

[0031]

[Table 1]

Example 4 Instead of coronate EH in Example 1, hexamethyl
Range isocyanate trimer isocyanate blocks
Block polyvalent isocyanate-based curing agent (product
Name: Coronate 2527 , manufactured by Nippon Polyurethane Industry Co., Ltd.)
To 10 parts by weight, coated on an aluminum plate in the same manner as in Example 1, and dried by heating at 220 ° C. for 2 minutes to obtain a fluorine-painted aluminum plate. The T-bending test result of this fluorine paint-coated aluminum plate was 0T, and the pencil hardness test result was 2H.

[0033] [Example 5] The formulation was dispersed having the following composition, (X) component and
A paint (c) containing the component ( Y) was obtained. (1) LF-600 70 parts by weight (2) LF-200 60 parts by weight (3) Titanium oxide 40 parts by weight (4) Methyl isobutyl ketone 30 parts by weight

100 parts by weight of paint (c), 8 parts by weight of coronate EH (manufactured by Nippon Polyurethane Industry Co., Ltd.) as a curing agent,
0.5 parts by weight of dibutyltin dilaurate (1% xylene solution) was mixed and stirred. This was coated on an aluminum plate to which an epoxy-based rust-preventive primer had been applied by a bar coater so as to have a dry coating thickness of 30 μm, and dried at room temperature to obtain a fluorine-painted aluminum plate. The T-bend test result of this fluorine-painted aluminum plate was 0T,
The result of the pencil hardness test was 2H.

Example 6 A composition having the following composition was dispersed to obtain a paint (d). (1) LF-600 70 parts by weight (2) Titanium oxide 40 parts by weight (3) Methyl isobutyl ketone 30 parts by weight

140 parts by weight of paint (d), LF-200
Was mixed with 16 parts by weight of Coronate EH (manufactured by Nippon Polyurethane Industry Co., Ltd.) as a curing agent and 1.0 part by weight of dibutyltin dilaurate (1% xylene solution). This was coated on an aluminum plate coated with an epoxy rust-preventive primer by a bar coater and dried to a thickness of 30 μm.
And dried at room temperature to obtain a fluorine paint-coated aluminum plate. The T-bending test result of this fluorine paint-coated aluminum plate was 0T, and the pencil hardness test result was 2H.

Comparative Example 5 A composition having the following composition was dispersed to obtain a paint (e). (1) LF-200 60 parts by weight (2) Titanium oxide 40 parts by weight (3) Methyl isobutyl ketone 30 parts by weight

130 parts by weight of paint (e), LF-600
, 70 parts by weight of, and 16 parts by weight of coronate EH (manufactured by Nippon Polyurethane Industry) and 1.0 part by weight of dibutyltin dilaurate (1% xylene solution) were mixed and stirred. This was coated on an aluminum plate coated with an epoxy rust-preventive primer by a bar coater and dried to a thickness of 30 μm.
And dried at room temperature to obtain a fluorine paint-coated aluminum plate. The T-bending test result of this fluorine paint-coated aluminum plate was 1T, and the pencil hardness test result was H.

According to the present invention, excellent weatherability, excellent workability such as scratch resistance and bending property, recoating property, color tone
A coated article having improved gloss and the like can be obtained.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-113051 (JP, A) JP-A-2-174977 (JP, A) JP-A-3-24145 (JP, A) JP-A-3-301 95276 (JP, A) JP-A-4-15276 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 127/12

Claims (1)

(57) [Claims] [Claim 1] A solvent-soluble fluororesin having a reactive group obtained by copolymerizing a fluoroolefin and a hydrocarbon monomer (X), solvent-comprising fluoroolefin and a hydrocarbon monomer copolymerized with the reactive group Melt-type fluororesin (Y) (except for (X) above) is added in a weight ratio of 1
/ 5-5 / 1 coating composition (provided that
"15-70% by weight of a fluoroolefin which may or may not contain vinylidene fluoride, and 85 of other vinyl monomers copolymerizable with the fluoroolefin.
And a fluoroolefin copolymer containing at least 80% by weight of a fluoroolefin containing vinylidene fluoride as an essential monomer component (B). As an essential component, the solid content weight ratio (A) / (B) of the copolymer (A) and the copolymer (B) is 50/50 to 99.9 /.
0.1, except that the fluororesin composition for paints is contained so as to be 0.1. And (X) an uncured glass.
The transition temperature _Tg is the glass transition temperature of the uncured state of (Y).
T _g than 5 ° C. or more low and coating composition, wherein greater than 10% than the growth rate of elongation (Y) of (X).