JPH03182569A - Metallic coating composition preventing electrostatic leak - Google Patents

Abstract

PURPOSE:To provide a coating compsn. enabling normal and stable electrostatic coating without causing electrostatic leak by compounding a polymer contg. specific phosphoric acid diester units into the compsn. CONSTITUTION:A (co)polymer of a hydroxylated, ethylenically unsatd. monomer (e.g. a hydroxyalkyl acrylate), a monohydric alcohol or phenol, and a compd. contg. a group of formula I in the molecule are reacted to give a polymer which contains 6-100wt.% phosphoric acid diester units of formula II (wherein A is a residue derived from the ethylenically unsatd. monomer; and R is alkyl or aryl) and has an acid value 25-400mg/KOH/g. A coating compsn. comprising a film-forming material, metallic pigment, solvent, and other necessary additives is compounded with the resulting polymer in an amt. of 5-30 pts.wt. based on 100 pts.wt. pigment.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention provides a novel metallic paint composition that prevents electrostatic leakage, and more specifically, the present invention provides an excellent metallic coating composition that does not cause electrostatic leakage during electrostatic coating and allows normal and stable coating. t: This relates to a metallic coating composition having electrostatic coating properties. [Prior art] In recent years, electrostatic coating has been developed to adhere paint to the object to be coated using electrical suction, so there is less paint loss, and it can be applied to protrusions and surrounding areas where brushing or spray painting does not adhere well. However, it is widely used for painting in various industrial fields because it produces a thick coating film and requires almost no labor. This electrostatic painting method usually uses a grounded object to be coated as an anode and a paint spraying device as a cathode, and applies a high voltage to create an electrostatic field between the two poles, which contains metallic pigments such as aluminum pigments. A method is used in which the metallic paint is scattered and charged, and then attracted to the object to be coated, which is the opposite polarity, to form a coating film. By the way, this kind of electrostatic painting often causes electrostatic leakage, making it difficult to paint properly.
This may lead to undesirable situations. therefore,
In order to enable normal and stable coating without causing electrostatic leakage, conventional methods have been attempted in which the surface of a metallic pigment is coated with a resin to make the metallic pigment an electrical insulator. However, with this method, the coating film formed may become darker than an untreated coating, which may impair the appearance of the coating film, or the metallic pigment may be deformed during circulation, resulting in insulation. It has disadvantages such as a decrease in performance. Furthermore, a metallic coating composition containing organic amine-modified hectorite to prevent electrostatic leakage has been proposed (Japanese Patent Laid-Open No. 113088/1988 1). In this composition, electrostatic leakage is prevented by forming an insulating film of an organic hectorite layer on the surface of the metal powder.
When preparing the composition, a step of dispersing the organic amine-modified hectorite is required, which inevitably complicates the operation, and the use of a large amount of the organic amine-modified hectorite reduces the water resistance of the coating film. There are drawbacks such as On the other hand, metallic coating compositions containing phosphoric acid mono- or diesters have been disclosed (JP-A-60-30168).
Publication No.). However, in this composition, the group phosphoric acid mono- or diester is added to prevent water discoloration of the coating film, and there is no explanation regarding prevention of electrostatic leakage, and the preferred phosphoric acid mono- or diester is Alternatively, a monoester of an ethylene oxide adduct of phosphoric acid is mentioned as the diester, and a polymer containing a phosphoric acid diester unit is not used in the examples as well.

[Problem to be solved by the invention]

Under these circumstances, the present invention does not cause electrostatic leakage when applying electrostatic coating. It has excellent electrostatic coating properties that enable normal and stable coating, and also has good circulator stability and the appearance of the coating film, as well as electrostatic leakage that can be easily prepared without the need for complicated operations. This was made for the purpose of providing a metallic paint composition with preventive properties. [Means for Solving the Problems] As a result of intensive research to develop an electrostatic leakage preventing metallic paint composition having the above-mentioned preferable properties, the present inventors discovered that a phosphate diester unit with a specific structure was By blending a predetermined amount of the contained polymer, we discovered that the purpose could be distantly related, and based on this knowledge, we completed the present invention. That is, the present invention provides a coating composition consisting of a film-forming material, a metallic pigment, a solvent, and a coating additive, which has the general formula (where A is a residue derived from an ethylenically unsaturated monomer and R is an alkyl An electrostatic leak-preventing metallic paint composition characterized by containing a polymer containing phosphoric diester units represented by (group or aryl group) at a ratio of 5 to 30 parts by weight per 100 parts by weight of pigment. It is something that provides something. The present invention will be explained in detail below. The composition of the present invention needs to contain a polymer having phosphoric acid diester units represented by the general formula (A and R in the formula have the same meanings as above). This polymer is, for example, (1) a homopolymer or copolymer of an ethylenically unsaturated monomer containing a hydroxyl group, a monohydric alcohol or a phenol, and the formula % () in the molecule. (2) Reacting a homopolymer or copolymer of ethylenically unsaturated phosphoric acid monoester with a monohydric alcohol or a phenol. (3)
Produced by polymerizing at least one ethylenically unsaturated phosphoric acid diester or copolymerizing at least one ethylenically unsaturated phosphoric acid diester and at least one ethylenically unsaturated monomer. I can do it. In the method (1) above, examples of the homopolymer of ethylenically unsaturated monomers containing hydroxyl groups include hydroxyacrylate, hydroxyethyl methacrylate, hydroxybutyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate,
A homopolymer of hydroxybutyl methacrylate, allyl alcohol, etc. can be used. Furthermore, as the copolymer of the ethylenically unsaturated monomer containing a hydroxyl group, a copolymer obtained by combining two or more of the ethylenically unsaturated monomers containing the hydroxyl group may be used. A copolymer of at least one ethylenically unsaturated monomer containing the hydroxyl group and at least one other ethylenically unsaturated monomer having no hydroxyl group may be used. Among these homopolymers and copolymers, especially copolymers of at least one ethylenically unsaturated monomer containing a hydroxyl group and at least one ethylenically unsaturated monomer having no hydroxyl group. Combination is preferred. Examples of the ethylenically unsaturated monomer having no hydroxyl group include methyl acrylate or methacrylate, ethyl acrylate or methacrylate, butyl acrylate or methacrylate, inbornyl acrylate or methacrylate, benzyl acrylate or methacrylate, and 2-ethylhexyl. Examples include acrylate or methacrylate, lauryl acrylate or methacrylate, isononyl acrylate or methacrylate, styrene, a-methylstyrene, vinyltoluene, vinyl acetate, and the like. Examples of the -hydric alcohols include alkanols such as methanol, ethanol, propatool, impropatol, butanol, imbutanol, amyl alcohol, cetyl alcohol, 2-ethylhexanol, nonyl alcohol, and lauryl alcohol; Examples of phenols include aryl alkanols such as alcohol, a-phenylethyl alcohol, and triphenylcarbinol; examples of phenols include phenol, 0-
Examples include lm- and p-cresol, p-t-butylphenol, and p-j-amylphenol. Well;
, alkylene oxides can be used instead of the above-mentioned -hydric alcohols. Furthermore, examples of compounds having a group represented by the formula % () in the molecule or compounds structurally equivalent thereto include orthophosphoric acid and phosphorus pentoxide. In the method (2) above, as a homopolymer of ethylenically unsaturated phosphoric acid monoester, for example, the general formula % formula % () (in the formula, R1 is a hydrogen atom or a methyl group, and B is an alkylene group) A homopolymerized ethylenically unsaturated phosphoric acid monoester represented by can be used. The general formula (I
The ethylenically unsaturated phosphoric acid monoester represented by II) can be easily produced from, for example, acrylic acid or methacrylic acid, an alkylene oxide, and phosphoric acid. Examples of such products include Hosmer M (R': CHs, B CH2CH!-), Hosmer P1, Hosmer C11 (trade names, manufactured by Unichemical Co., Ltd.), and MR-200 (
Commercially available products such as Oiri Kagaku Co., Ltd., trade name) and AR-200 (Oiri Kagaku Co., Ltd., trade name) can be mentioned. Furthermore, as the copolymer of ethylenically unsaturated phosphoric acid monoester, a copolymer of two or more ethylenically unsaturated phosphoric acid monoesters represented by the general formula (I[[) may be used. Alternatively, a copolymer of at least one ethylenically unsaturated monoester of sulfuric acid and at least one other ethylenically unsaturated monomer may be used. Among these homopolymers and copolymers of ethylenically unsaturated phosphoric acid monoesters, at least one ethylenically unsaturated phosphoric acid monoester represented by the general formula CI [[] and other ethylene Copolymerization with at least one sexually unsaturated monomer is preferred. Other ethylenically unsaturated monomers used here are exemplified as ethylenically unsaturated monomers having no hydroxyl group in the explanation of method (1) above. ＝I can name things. The m alcohols or phenols used in method (2) include those exemplified in the description of method (1) above. As the ethylenically unsaturated phosphoric acid diester used in the method (3) above, for example, a compound represented by H... (IV) (wherein R1, R and B have the same meanings as above) Can be mentioned. This ethylenically unsaturated phosphoric acid diester can be easily produced by reacting the ethylenically unsaturated phosphoric acid monoester represented by the general formula (■) with the m alcohols or phenols. can. Examples of such a compound include, for example, a compound obtained by reacting phosmer M with ethyl alcohol. In this method (3), one type of ethylenically unsaturated phosphoric acid diester may be polymerized to form a homopolymer, or two or more types may be polymerized to form a copolymer. , and at least one ethylenically unsaturated sulfonic acid diester and at least one other ethylenically unsaturated monomer.
The species may be polymerized to form a copolymer. Among these homopolymers and copolymers, copolymers obtained by polymerizing at least one ethylenically unsaturated sulfonic acid diester and at least one other ethylenically unsaturated monomer are particularly preferred. suitable. Other ethylenically unsaturated monomers used in this case include those exemplified as ethylenically unsaturated monomers having no hydroxyl group in the explanation of the method (1) above. In this way, a polymer containing a phosphoric diester unit represented by the general formula (I) is obtained, but in the present invention, as described above, this phosphoric diester unit and an ethylenically unsaturated monomer are used. Copolymers consisting of mer units are preferred. In such a copolymer, the general formula (1
) The content of phosphoric acid diester units is 6 to 10
Advantageously, it is in the range 0% by weight. Also, the polymer containing this phosphoric acid diester unit is such that R in the phosphoric acid diester unit or a part of the ethylenically unsaturated monomer unit of the copolymerization component has 6 to 22 carbon atoms. A polymer formed from a compound having a terminal organic group is preferable, but in this case, the content of the compound residue having a terminal organic group having 6 to 22 carbon atoms in the polymer is equal to that of the polymer excluding the phosphoric acid group. It is desirable that the amount is 25% by weight or less based on the weight of . If this content exceeds 25% by weight, the coating film adhesion tends to decrease, which is not preferable. Examples of compounds having a terminal organic group having 6 to 22 carbon atoms used to form the nucleus R include 2-ethylhexanol, benzyl alcohol, α-phenylethyl alcohol, triphenylcarbinol, cresol, pt-butylphenol, p-
Examples of the compound having a terminal organic group having 6 to 22 carbon atoms used for forming the ethylenically unsaturated monomer unit of the copolymerization component include benzyl acrylate or methacrylate, 2- Examples include ethylhexyl acrylate or methacrylate, lauryl acrylate or methacrylate 1, innonyl acrylate or methacrylate. Further, the acid value of the polymer containing the phosphoric acid diester unit is preferably in the range of 25 to 4001191 [OB/9, preferably 40 to 200 my)[O[1/9]. If this acid value deviates from the above range, the object of the present invention cannot be fully achieved, which is not preferable. There are no particular limitations on the film-forming material used in the composition of the present invention, and any material can be selected from those commonly used in conventional solvent-based metallic paints. Examples of the film forming material include acrylic resin, polyester resin, acrylic/cellulose acetate butyrate (hereinafter abbreviated as CAB) mixed resin,
Synthetic resins such as CAB-grafted aguacrylic resins, urethane resins, epoxy resins, silicone resins, polyamide resins, epoxy-modified alkyd resins, and phenolic resins, as well as various natural resins and cellulose derivatives, can be used. These film-forming materials may be used alone or in combination of two or more, and if necessary, may be used with a curing agent such as a melamine resin, an incyanate compound, a blocked incyanate compound, or a polyamine compound. May be used in combination. There are no particular restrictions on the metallic pigments used in the composition of the present invention, and those commonly used in conventional metallic paints, such as aluminum, aluminum-copper alloy, aluminum-zinc alloy, aluminum-nickel alloy, aluminum-magnesium Examples include aluminum alloys such as alloys, and those exhibiting electrical conductivity such as copper, brass, and nickel. These may be in powder form,
7 It may be in the form of a lake, or one type may be used,
Although two or more types may be used in combination, aluminum flakes are particularly suitable in the present invention. These metallic pigments are generally commercially available in paste form. In the composition of the present invention, inorganic pigments, organic pigments, extender pigments, and the like may be used in combination with the metal pigments, if desired. Further, there are no particular limitations on the solvent used in the composition of the present invention, and solvents commonly used in conventional solvent-based metallic paints, such as aromatic hydrocarbons such as toluene and xylene, olefins, cycloolefins, naphthas, Methanol, ethanol, inproper tool, n-
Alcohols such as butanol, methyl ethyl ketone,
Ketones such as methyl isobutyl ketone, ethyl acetate,
Esters such as butyl acetate, chlorine compounds such as dimethylene chloride and trichloroethylene, glycol ethers such as glycol monoethyl ether and glycol monobutyl ether, glycol monoether monoesters such as glycol monomethyl ether acetate and glycol monoethyl ether acetate. You can list things like this. These solvents may be used alone or in combination of two or more. In the composition of the present invention, one type of polymer containing phosphoric acid diester units represented by the general formula (1) may be used, or two or more types may be used in combination, and the amount thereof is 5 to 100 parts by weight of the metal pigment.
It is necessary to select within the range of 30 parts by weight. This amount is 5
If it is less than % by weight, the electrostatic leakage prevention effect is insufficient;
If it exceeds 30% by weight, it may cause blistering in terms of coating film performance, especially water resistance. In this way, by blending a polymer containing the phosphoric acid diester unit into a metallic paint, the phosphoric acid group strongly bonds with the metal pigment in the metallic paint, forming a protective layer on the particle surface of the metal pigment. On the other hand, since the organic residue part of the polymer is compatible with the film-forming material of the paint,
Metallic pigments are stabilized in paints. The protective layer formed on the surface of the metallic pigment particles is much more strongly adsorbed to the surface of the metallic pigment particles than a protective layer simply formed from a film-forming material, as in conventional metallic paints. Therefore, the metallic paint composition of the present invention does not cause electrostatic leakage or electrostatic agglomeration even when electrostatically applied under high voltage, and enables normal and stable coating. This treatment does not cause discoloration such as darkening of the metallic pigment. The electrostatic leak-preventing coating composition of the present invention can be produced by repeatedly turning on and off an applied voltage of 10 to 90 kV at 5-second intervals while supplying the composition for 60 seconds using an electrostatic coating device. In the electrostatic leak test, it has excellent electrostatic leak prevention properties, with no electrostatic leakage for up to 30 seconds. If desired, other additive components conventionally used in solvent-based metallic paints, such as surface conditioners, light stabilizers, antioxidants, etc., may be added to the composition of the present invention. [Example 1] Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited in any way by these examples. In addition, the electrostatic leakage prevention property of the coating composition was determined according to the following method. As an electrostatic coating device that prevents electrostatic leakage, the gun tip can apply up to 90 kV, a metal joint is provided between the gun and the metallic pulp, and the length of the paint hose from the metal joint to the gun is 20 cm. At the same time, the metal joint was connected to a pen recorder with a resistance of Ω via a lead wire so that the current value could be measured. If electrostatic leakage does not occur during application, the current value is stable within a certain range, but if electrostatic leakage occurs, the current value suddenly increases and shows an abnormal value. The electrostatic leak prevention property was evaluated according to the following criteria by filling the paint composition to be tested up to the gun tip of the electrostatic coating device and repeating the set applied voltage ON and OFF at 5 second intervals while supplying the paint for 60 seconds. Find it according to t;. 0: Does not leak until the end, i.e., does not leak until 60 seconds Δ: Does not leak until 30 seconds Production of Combined A 110 parts by weight of xylene was charged into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a separator, and the temperature was raised to 140°C.
While stirring, add 10 parts by weight of styrene, 38 parts by weight of butyl methacrylate, 1 part by weight of 2-ethylhexyl methacrylate.
7 parts by weight of methyl methacrylate, 30 parts by weight of hydroxyethyl methacrylate, and 3 parts by weight of azobisisobutyronitrile were added dropwise over 4 hours. After the dropwise addition was completed, the temperature was kept at 140°C for 30 minutes, and then t-
A mixed solution of 0.2 parts by weight of butylperoxy-2-ethylhexanoate and 2 parts by weight of xylene was added, and the mixture was further maintained at 140°C for 30 minutes. A mixed solution of 0.2 parts by weight and 2 parts by weight of xylene was added and held at 140°C for 30 minutes. After repeating this operation two more times,
The polymerization reaction was completed by holding at O for 1 hour. This resin solution was cooled to 60°C, 33.7 parts by weight of butyl alcohol was added thereto, a suspension consisting of 50 parts by weight of xylene and 32.8 parts by weight of phosphorus pentoxide was added, and the temperature was maintained for 3 hours. The temperature was raised to 140"C, during which time 3 parts by weight of water were removed. In this way, phosphoric acid diester group-containing polymer A having an acid value of 90 mg KOH/9 (residue on heating) was obtained.
A solution of was obtained. Table 1 shows the amounts of each component used in the polymerization. Production Example 2 Production of Phosphoric Diester Group-Containing Polymer B In a reaction vessel similar to Production Example 1, RJloo (manufactured by Monsanto Chemical Company, trade name, styrene/aryl alcohol copolymer) 3 was added.
4.75 parts by weight, pt-amylphenol 10.62
parts by weight and 40 parts by weight of xylene were charged, and the mixture was heated at 85 to 90°C and stirred until the solid components were dissolved. Then,
4.63 parts by weight of phosphorus pentoxide and 10 parts by weight of xylene were added and the temperature was raised to the reflux temperature of xylene and held for 3 hours. At this time, 0.3 parts by weight of water was removed. In this way, a solution of phosphoric acid diester group-containing polymer B having an acid value of 1001119 KOH/9 (heated residue) was obtained. Table 1 shows the amounts of each component used in the polymerization. Production Example 3 Production of Phosphoric Diester Group-Containing Polymer C Into the same reaction vessel as in Production Example 1, 54 parts by weight of xylene and 40 parts by weight of methyl amyl ketone were charged, heated to 140°C, and then heated to 140°C while stirring. 20 parts by weight of Hosmer M, 20 parts by weight of styrene, 38 parts by weight of butyl methacrylate, 17 parts by weight of butyl acrylate, 5 parts by weight of methyl methacrylate, t
-4 parts by weight of butyl peroxybenzoate were added dropwise over 4 hours. After the dripping was completed and held at 140°C for 1 hour,
A mixture of 7 parts by weight of pt-amylphenol and 7 parts by weight of xylene was added and held at 140°C for 3 hours. At this time, 1.5 parts by weight of water was removed and 5011gKOR/
A solution of a phosphoric acid diester group-containing polymer C having an acid value of g (heated residue) was obtained. Table 1 shows the amount of each component used in the polymerization. (The following is a blank space) Example 1 First, an acrylic melamine type metallic paint having the following composition was prepared. Alpaste 170ONL (aluminum paste) (
Manufactured by Toyo Aluminum Co., Ltd., product name) 5 parts by weight xylene 5! Part by weight Phosphoric acid diester group-containing polymer A 0.4 part by weight Acrydic 47-712 (acrylic resin) (manufactured by Dainippon Ink & Chemicals, trade name) 42Il Part by weight Super Beckamine L-117-60 (melamine resin ) (manufactured by Dainippon Ink and Chemicals, trade name) 15 parts by weight xylene 1
2.6 parts by weight, that is, Alpaste 170ONL,
After adding xylene and phosphoric acid diester group-containing polymer A and stirring at room temperature for 30 minutes, Acrydic 47-712 was added.
, Super Beckamine L-117-60, and xylene were added, and stirring was continued for an additional 30 minutes to obtain a metallic paint. Next, the metallic paint thus obtained was further diluted with 49 parts by weight of toluene, 14 parts by weight of butyl acetate, and 7 parts by weight of inbutanol to prepare a paintable external paint composition. The composition of this paint composition is shown in Table 2, and the evaluation results of the electrostatic leak prevention properties are shown in Table 3! l! Shown below. Examples 2 to 5 Coating compositions having the compositions shown in Table 2 were prepared in the same manner as in Example 1, and their electrostatic leak prevention properties were evaluated. The results are shown in Table 3. Example 6 First, an acrylic melamine type metallic paint having the following composition was prepared. Bentone 34 (organic bentonite) (manufactured by National Red Co., Ltd., trade name) 5 parts by weight Xylene 4.6 parts by weight Methanol 0.15 parts by weight Alpaste 170O
NL (mentioned above) 5 parts by weight Xylene 5 parts by weight Phosphoric acid diester group-containing polymer B 0.8 parts by weight Acridic 47-712 (stated above) 42 parts by weight Super Beckamine L-117-60 (stated above) 15 Part by weight xylene
7.2 parts by weight, i.e. Bentone 34
Xylene and methanol were added to the mixture, and the mixture was mixed and dispersed using a grind mill for 1 hour to obtain a paste of Bentone 34. Add xylene and phosphoric acid diester group-containing polymer B to Alpaste 170ONL, stir at room temperature for 30 minutes, add Bentone 34 paste, continue stirring for another 30 minutes, add Acridic 47-712, Super Beckamine L-117-60. Xylene was added and the mixture was stirred for an additional 30 minutes to obtain a metallic paint. Next, the metallic paint thus obtained was further diluted with 49 parts by weight of toluene, 14 parts by weight of butyl acetate, and 7 parts by weight of inbutanol to prepare a paintable paint composition. The composition of this composition is shown in Table 2, and the evaluation results of the electrostatic leak prevention properties are shown in Table 3. Comparative Examples 1 to 3 Comparative Examples 1 and 2 were prepared in the same manner as in Example 1, and Comparative Example 3 was in the same manner as in Example 6 to prepare coating compositions having the compositions shown in Table 2. Riff prevention properties were evaluated. The results are shown in Table 3. It is clear from Table 3 that all of the coating compositions of the present invention have a large electrostatic leak prevention effect, but all of the compositions of the comparative examples have an extremely small electrostatic leak prevention effect. (The following is a blank space) [Effects of the Invention] According to the present invention, by blending a phosphoric acid diester group-containing polymer into a metallic paint composition, this polymer is firmly adsorbed to the surface of the metallic pigment particles and forms a protective layer. Even if the composition is electrostatically coated under high voltage to form
Normal and stable painting is possible without causing electrostatic leakage or electrostatic aggregation. In addition, the antistatic metallic paint composition of the present invention does not cause discoloration such as darkening of the metallic pigment, has excellent circulation stability, and does not require complicated operations and can be easily applied. It can be prepared.

Claims (1)

[Claims] 1. In a coating composition consisting of a film-forming material, a metallic pigment, a solvent, and a coating additive, there are general formulas, mathematical formulas, chemical formulas, tables, etc.▼...(I) (A in the formula is ethylene) Contains a polymer containing a phosphoric acid diester unit represented by a residue derived from a sexually unsaturated monomer (R is an alkyl group or an aryl group) in a proportion of 5 to 30 parts by weight per 100 parts by weight of the pigment. A metallic paint composition that prevents electrostatic leakage. 2. The composition according to claim 1, wherein the polymer is a copolymer consisting of a phosphoric acid diester unit represented by the general formula (I) and an ethylenically unsaturated monomer unit. 3.Claim 2, wherein the content of phosphoric acid diester units represented by general formula (I) in the copolymer is 6 to 100% by weight.
Compositions as described. 4. Claims 1 to 3, wherein the polymer contains a compound residue having a terminal organic group having 6 to 22 carbon atoms in a proportion of 25% by weight or less based on the weight of the polymer excluding phosphoric acid groups.
The composition according to any one of. 5. The composition according to any one of claims 1 to 4, wherein the polymer has an acid value of 25 to 400 mgKOH/g. 6 In an electrostatic leak test in which an applied voltage of 10 to 90 kV is repeated on and off at 5 second intervals while the composition is supplied for 60 seconds using an electrostatic coating device, no electrostatic leak occurs for up to 30 seconds. The composition according to any one of claims 1 to 5.