JP2857178B2 - Methacrylic lacquer composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a methacrylic lacquer composition having excellent weather resistance, and in particular, has excellent weather resistance, that is, excellent gloss retention over a long period of time. The present invention relates to a methacrylic lacquer composition exhibiting excellent crack resistance, blister resistance and yellowing resistance, and having excellent gloss, drying properties and pigment dispersibility.

[Prior Art] Conventionally, methacrylic lacquers have been widely known as methacrylic resin coatings. This methacrylic lacquer has better weather resistance, chemical resistance, water resistance, etc. than alkyd resin paints or other various resin paints, and further, in terms of its use, polyisocyanate compounds such as ordinary curable resins. There is no need to mix and use a hardening agent such as aminoplast resin, so there is an advantage that it can be used easily, and it is used in a wide range of fields such as building materials, woodwork, tiles, paper, and metals.

However, from the viewpoint of the durability of the coating film,
Its level is lower than that of a curable resin. That is, when compared with the gloss retention of the accelerated weather resistance test (sunshine weatherometer), the acrylic-based curable resin, which is conventionally considered to have relatively good weather resistance, has a 2,000 curable resin.
Methacrylic lacquers are on the level of less than 1,000 hours, compared to levels of 0-3,000 hours.

On the other hand, as a paint having good weather resistance, a composition containing a methacrylic urethane, a silicone resin, a fluororesin as a main component is known, and is used for various purposes. Lacquer-type resin that does not require a cross-linking agent, therefore, has excellent long-term weather resistance, that is, the gloss retention in accelerated weather resistance test is at a level of 2,000 hours or more. The development of a lacquer composition which is excellent in meat characteristics, sharpness, drying property and pigment dispersibility has been awaited.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned circumstances, and its object is to provide a long-term weather resistance equivalent to or more than that of a curable paint having relatively good weather resistance. An object of the present invention is to provide a methacrylic lacquer composition which gives a coating film having excellent properties.

[Means for Solving the Problems] The methacrylic lacquer composition of the present invention comprises a polymerizable ultraviolet-stable monomer (a) represented by the general formula (I), an acidic functional group-containing polymerizable monomer ( a) a polymerizable monomer component containing b) and another polymerizable monomer (c) as an essential component [provided that all monomers are copolymerized except when they are fluorine-containing monomers. And a coating film having excellent long-term weather resistance and gloss retention, and excellent crack resistance and blister resistance. In this specification, the expression "(meth) acryl-" is used when "acryl- and / or methacryl-" is to be collectively displayed.

[Action] The polymerizable ultraviolet light-stable monomer (a) represented by the general formula (I) is an essential compound for imparting excellent weather resistance to the copolymer, and is typically represented by carbon black. The effect of improving the dispersibility of the acidic pigment and the color mixing stability in the composite pigment system is also remarkably exhibited.

Wherein R ₁ is a hydrogen atom or a cyano group; R ₂ and R ₃ are each independently a hydrogen atom or an alkyl group having 1 to 2 carbon atoms; X is an imino group or an oxygen atom; Y is a hydrogen atom; ~ 18
An alkyl group or (R ₂ and R ₃ have the same meanings as described above)] In the above definition, the alkyl group having 1 to 2 carbon atoms represented by R ₂ and R ₃ is methyl or ethyl and has 1 carbon atom represented by Y Examples of the alkyl group of ~ 18 include methyl, ethyl,
Linear or branched represented by propyl, isopropyl, butyl, isobutyl, tertiary butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, etc. A hydrocarbon residue is shown.

More specifically, the polymerizable ultraviolet-stable monomer (a) may be, for example, 4- (meth) acryloyloxy-2,2,6,6-tetramethyl. Piperidine, 4- (meth) acryloylamino-2,
2,6,6-tetramethylpiperidine, 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine,
4- (meth) acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1-
(Meth) acryloyl-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth)
Acryloyl-4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine,
4-crotonoylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-
Examples thereof include 2,2,6,6-tetramethylpiperidine, and one or more of these can be used.

Examples of the acidic functional group-containing polymerizable monomer (b) include carboxyl group-containing polymerizable monomers such as (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid and maleic anhydride; vinyl sulfonic acid Sulfonic acid group-containing polymerizable monomers such as styrene sulfonic acid and sulfoethyl (meth) acrylate; 2- (meth) acryloyloxyethyl acid phosphate, 2- (meth) acryloyloxypropyl acid phosphate,
Examples thereof include acidic phosphate ester-based polymerizable monomers such as (meth) acryloyloxy-3-chloropropyl acid phosphate and 2-methacryloyloxyethylphenylphosphoric acid.

Other polymerizable monomers (c) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate Tertiary butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, tertiary
(Meth) acrylic acid alkyl esters such as tert-butylcyclohexyl (meth) acrylate; epoxy group-containing polymerizable monomers such as glycidyl (meth) acrylate;
Nitrogen-containing polymerizable monomers such as (meth) acrylamide, N, N'-dimethylaminoethyl (meth) acrylate, vinylpyridine and vinylimidazole; halogen-containing polymerizable monomers such as vinyl chloride and vinylidene chloride; styrene; Aromatic polymerizable monomers such as α-methylstyrene and vinyltoluene; vinyl esters such as vinyl acetate; vinyl ethers; polymerizable cyanides such as (meth) acrylonitrile; hydroxymethyl (meth) acrylate, hydroxypropyl (meth) Acrylate, caprolactone-modified hydroxy (meth) acrylate [for example, Placcel FM, Daicel Chemical Industries, Ltd.]
Polymerizable monomers having a hydroxyl group, such as mono (meth) acrylate of polyester diol obtained from phthalic acid and propylene glycol,
2-hydroxy-4- [3- obtained by reacting 4-dihydroxybenzophenone or 2,2 ', 4-trihydroxybenzophenone with glycidyl (meth) acrylate
(Meth) acryloxy-2-hydroxypropoxy]
Benzophenone, 2,2'-dihydroxy-4- [3-
(Meth) acryloxy-2-hydroxypropoxy]
Examples thereof include polymerizable ultraviolet absorbing monomers such as benzophenone and the like, and one or more kinds selected from these groups can be used.

When the copolymer (X) is produced from a monomer component containing the monomers (a), (b) and (c), each of the monomers (a), (b) and (c) is used. The proportions used are generally 0.1 to 10% by weight of the polymerizable ultraviolet-stable monomer (a), 0.1 to 10% by weight of the acidic functional group-containing polymerizable monomer (b), and other polymerizable monomers. It is preferable to use 99.8 to 80% by weight of the monomer (c). Here, when the amount of the polymerizable ultraviolet-stable monomer (a) used is less than 0.1% by weight, the light stability of the obtained copolymer (X) is insufficient. On the other hand, if the content is more than 10% by weight, when a lacquer composition is formed into a coating, the gloss and the feeling of holding of the coating film are insufficient, resulting in unsatisfactory appearance, and poor solvent resistance and chemical resistance. is there. The acidic functional group-containing polymerizable monomer (b) has a useful effect in imparting pigment dispersibility to the copolymer of the present invention. It is sufficient if the amount used is 0.1% by weight or more, but if it is used in excess of 10% by weight, it will cause instability during polymerization, lower the water resistance of the obtained copolymer, and stabilize the ultraviolet light. In some cases, the action of the monomer is hindered, resulting in disadvantages such as difficulty in obtaining long-term weather resistance.

The other polymerizable monomer (c) is preferably selected so as not to detract from the essential characteristics of the present invention. For example, aromatic polymerizable monomers generally used in terms of gloss, meat properties, solvent resistance and chemical resistance are negative in terms of long-term weather resistance which is a feature of the present invention. Yes, in all components (a) to (c) of the polymerizable monomer
It is recommended that the content be 20% by weight or less, preferably 10% by weight or less, more preferably 5% by weight or less. Further, in order to further remarkably exhibit long-term weather resistance, it is particularly preferable that the content of methacrylic acid and methacrylic esters in all components of the polymerizable monomer is 50% by weight or more.

However, the methacrylic acid ester referred to here is a polymerizable unsaturated monomer derived from a methacryloyl group among monomers composed of a polymerizable ultraviolet-stable monomer (a) and another polymerizable monomer (c). Means having a group. In particular, a cycloalkyl group-containing (meth) acrylate (II) is preferable for applications requiring beautiful feeling such as glossiness and meat properties in addition to long-term weather resistance. The cycloalkyl group-containing (meth) acrylate is also an advantageous substance in terms of controlling the glass transition temperature described below.

(In the formula, R ₄ represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, and Z represents a cycloalkyl group optionally having a substituent.) A cycloalkyl optionally having a substituent represented by Z Examples of the cycloalkyl group in the group include monocyclic saturated hydrocarbon residues such as cyclopentyl, cyclohexyl, and cyclododecyl. These cycloalkyl groups may have an alkyl group having 1 to 6 carbon atoms as a substituent. Examples of the alkyl group in these substituents include methyl, ethyl, propyl, isopropyl, butyl, isobutyl and tertiary alkyl. Grade butyl, pentyl, hexyl,
Heptyl and the like are exemplified.

More specific examples of the compound name will be described, for example, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, tertiary butylcyclohexyl (meth) acrylate, and the like. Species or two or more can be used. Differential scanning calorimeter (DS) of the copolymer (X) of the present invention
The glass transition temperature measured using C) is preferably designed to be in the range of 20 ° C to 80 ° C.

If the glass transition temperature of the copolymer (X) is less than 20 ° C., the coating film is too flexible, which is insufficient from the viewpoint of long-term durability. ,
Conversely, the coating film is too hard and brittle, resulting in disadvantages in crack resistance and blister resistance. Still more preferably, it is recommended to be in the range of 30 to 70 ° C.

Furthermore, the number average molecular weight of the copolymer (X) of the present invention is
It is preferable to design so as to be in the range of 10,000 to 40,000. When the number average molecular weight of the copolymer (X) is less than 10,000, a coating film having sufficient durability cannot be obtained,
On the other hand, when it exceeds 50,000, disadvantages such as instability at the time of polymerization are induced and the viscosity is so high that the coating workability is poor. Still more preferably, it is recommended to be in the range of 15,000 to 30,000. Furthermore, the number average molecular weight is 10,000
Even above, it is said that if a component having a number average molecular weight of 5,000 or less is present in the copolymer (X) in an amount of 10% by weight or more, it is difficult to obtain a sufficiently durable coating film or lacks solvent resistance. Due to disadvantages, it is recommended that the copolymer (X) contains less than 10% of components having a number average molecular weight of 5,000 or less.

Next, a method for producing the copolymer (X) of the present invention will be described. The copolymer (X) is a polymerizable monomer comprising the polymerizable UV-stable monomer (a), the acidic functional group-containing polymerizable monomer (b), and another polymerizable monomer (c). It is obtained by polymerizing the body component by a known method, for example, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, or a bulk polymerization method. Solvents that can be used when the solution polymerization method is employed include aromatic hydrocarbons such as toluene and xylene; acetates such as ethyl acetate and butyl acetate; ketones such as methyl ethyl ketone and methyl isobutyl ketone; isopropanol;
Aliphatic alcohols such as -butanol and iso-butanol; alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and diethylene glycol monoethyl ether; and these organic solvents can be used alone. Alternatively, it is used as a mixed solvent.

Examples of the polymerization initiator include ordinary radical polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, and ditertiary butyl peroxide. These polymerization catalysts are used in the range of 0.1 to 10% by weight based on the total weight of the polymerizable monomer. The reaction temperature ranges from room temperature to 200 ° C, preferably 40 to 140 ° C.
Also, when performing the polymerization reaction, for the purpose of adjusting the molecular weight,
Chain transfer agents and regulators such as lauryl mercaptan, 2-mercaptoethanol, carbon tetrachloride and carbon tetrabromide may be used.

When the copolymer (X) obtained in the present invention is used as a water-soluble or water-dispersible type, it may be neutralized with a basic compound, if necessary. Examples of the basic compound that can be used include ammonia, triethylamine,
Examples include morpholine and sodium hydroxide.

The lacquer composition of the present invention comprises a solvent such as an organic solvent and / or water, a filler, a leveling agent, a dispersant, a plasticizer,
Various paint additives such as stabilizers, dyes, and pigments can be appropriately blended and used.

Examples of the pigment in the case where the lacquer composition of the present invention is blended with the lacquer composition and used as a paint include, for example, inorganic pigments such as titanium oxide, antimony trioxide, zinc white, lithopone, white pigments such as lead white, carbon black, and yellow. Colored pigments such as lead, molybdenum red and red iron or organic pigments such as benzidine and azo compounds such as Hansa Yellow and phthalocyanines such as phthalocyanine blue can be used, and one or more of these can be used. .

In addition, it is recommended that these pigments be selected from pigments having good weather resistance so as not to lower the weather resistance of the coating film. For example, as titanium oxide which is a white pigment, anatase type titanium oxide Using rutile-type titanium oxide gives better results in terms of the weather resistance of the coating film than using titanium oxide. Further, even if it is a rutile type, titanium oxide by chlorine method is more preferable than titanium oxide by sulfuric acid method in terms of exhibiting long-term weather resistance.

[Effect of the Invention] Since the lacquer composition of the present invention is obtained by using a polymerizable monomer component having a specific composition, it has excellent long-term weather resistance and excellent pigment dispersibility. Inorganic and organic pigments can be dispersed by a known pigment dispersion method to form a colored coating.

The lacquer composition of the present invention has excellent long-term weather resistance, as well as glossiness, meat properties, and a film-forming ability with excellent solvent resistance and excellent workability. It can be used for a wide range of applications, such as steel equipment, large structures, automobiles, building materials and woodworking.

[Examples] Hereinafter, the present invention will be described using Examples and Comparative Examples.

Unless otherwise specified, “parts” or “%” means parts by weight or% by weight, respectively.

Production Example 1 4 with stirrer, thermometer, cooler, and nitrogen gas inlet tube
Under a nitrogen gas stream in a one-necked flask, 50 parts of toluene was charged, and the temperature was raised to 75 ° C. while 4-methacryloyloxy-2,
2,6,6-tetramethylpiperidine 1.0 part, methyl acrylate 28.0 parts, butyl acrylate 10.8 parts, vinyl acetate 1
A polymerizable monomer component consisting of 0.0 part, 0.2 part of methacrylic acid and 0.2 part of benzoyl peroxide was dropped over 2 hours and further kept at 75 ° C. for 4 hours to obtain a copolymer of the present invention [copolymer Solution (1)] was obtained. The characteristic values are shown in Table 1.

Production Examples 2 to 4, Comparative Production Examples 1 to 9 The polymerizable monomer, solvent, polymerization initiator, and temperature during the polymerization reaction used in Production Example 1 were set as shown in Tables 1 and 2. Except for this, the same operation as in Production Example 1 was repeated to obtain copolymer solutions (2) to (4) and copolymer solutions (1) to (9) for comparison.

Comparative Production Example 10 Toluene 27 was placed in the same reactor as in Production Example 1 under a nitrogen gas stream.
And methacryloyloxy-1,2,2,6,6-pentamethylpiperidine 0.8 part, tert-butylcyclohexyl methacrylate 16.0 parts, stearyl methacrylate 7.1 parts, methyl methacrylate 16.0
, 10% of the polymerizable monomer component consisting of 0.9 parts of methacrylic acid and 0.1 part of benzoyl peroxide, and after 10 minutes, the remaining 90% of the polymerizable monomer is lowered over 2 hours. And kept at 70 ° C for 1 hour
22 parts were added and further kept at 70 ° C. for 4 hours.
11 parts were added to obtain a comparative copolymer solution (9). The characteristic values are shown in Table 2.

Production Example 5 The same reactor as used in Production Example 1 was charged with 40 parts of isopropyl alcohol under a nitrogen gas stream, and 0.1 part of 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine and cyclohexyl methacrylate were used. 22 parts, butyl methacrylate 15 parts, methyl methacrylate 7.0 parts,
A polymerizable monomer component consisting of 10.9 parts of methyl acrylate, 5.0 parts of acrylic acid and 0.2 parts of azobisisobutyronitrile was lowered over 4 hours, and further kept at 80 ° C. for 4 hours, and then 10.8 parts of triethylamine was added. And neutralized to obtain a copolymer of the present invention [referred to as copolymer solution (5)]. The characteristic values are shown in Table 1.

Comparative Production Example 11 A comparative copolymer solution (11) was obtained by repeating the same operation as in Production Example 5 except that the polymerizable monomers used in Production Example 5 were changed as shown in Table 2. Was.

Examples 1-3 and Comparative Examples 1-6 The copolymer solutions (1), (2), (3) obtained in Production Examples 1, 2, 4 and Comparative Production Examples 1, 2, 5, 6, 9, 10. ) And comparative copolymer solutions (1), (2), (5), (6), (9), (1)
Lacquer composition (1),
(2), (3) and comparative lacquer composition (1),
(2), (3), (4), (5) and (6) were prepared.

The lacquer composition was spray-coated on a white plate previously coated with a two-component urethane resin enamel on a zinc phosphate-treated plate, and dried at room temperature for one week to test the coating film performance using a test piece obtained. did. The film thickness was 20 μm. As shown in Table 4, the results had excellent weather resistance.

Examples 4 to 8 and Comparative Examples 7 to 12 The copolymer solutions (1), (2), and (3) obtained in Production Examples 1, 2, and 3 and Comparative Production Examples 1, 3, 4, 7, 8, and 9 ) And the copolymer solutions (1), (3), (4), (7), (8) and (9) for comparison and the lacquer compositions (4) to
(8) and comparative lacquer compositions (7) to (12) were prepared.

These lacquer compositions were spray-coated on a zinc phosphate-treated plate and dried at room temperature for one week to test the coating film performance using a test piece obtained. The film thickness was 20 μm.
As shown in Table 6, the results had excellent weather resistance.

Example 9 and Comparative Example 13 The lacquer composition (9) and the comparative lacquer composition (9) were prepared using the copolymer solution (5) and the comparative copolymer solution (11) obtained in Production Example 5 and Comparative Production Example 11 with the following composition. A lacquer composition (13) was prepared.

Formulation (part) Copolymer liquid or Comparative copolymer liquid 100 Water 23 Butyl cellosolve 10 Spray-coat these lacquer compositions on a white plate which has been previously coated with a two-component urethane resin enamel on a zinc phosphate-treated plate and allowed to reach room temperature. The coating film performance was tested using a test piece obtained by drying for 1 week. The film thickness was 20 μm. As shown in Table 7, the results had excellent weather resistance.

Example 10 and Comparative Example 14 Using the lacquer compositions (5), (7) and (8) obtained in Examples 5, 7, 8 and Comparative Example 12 and the comparative lacquer composition (12), Table 8 shows the results. The lacquer composition (10) and the comparative lacquer composition (14) were obtained by mixing with the indicated composition.

These lacquer compositions are spray-coated on a tin plate, and when the coating becomes semi-dry (the coating becomes a stringing state when touched with a finger), a part of the coating is rubbed with a finger. The color difference between the rubbed surface and the spray surface and the gloss value of the spray surface were tested. The results are as shown in Table 8,
It had excellent pigment dispersibility.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08F 220: 06) (72) Inventor Tatsuto Matsuda 5-8 Nishiburi-cho, Suita-shi, Osaka Nippon Shokubai Chemical Industry Co., Ltd. In the laboratory (56) References JP-A-2-151647 (JP, A) JP-A-2-28109 (JP, A) JP-A-54-71185 (JP, A) JP-A-63-35660 (JP, A) JP-A-1-261409 (JP, A) JP-A-57-180616 (JP, A) JP-A-54-21489 (JP, A) JP-A-57-108171 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) C09D 133/04-133/14 C08F 220/10-220/28 C08F 20/10-20/28

Claims (5)

(57) [Claims] 1. A polymerizable ultraviolet-stable monomer (a) represented by the following general formula (I): 0.1 to 10% by weight, an acidic functional group-containing polymerizable monomer (b) 0.1 to 10% by weight, 99.8 to 80% by weight of other polymerizable monomer (c) [however, (a), (b),
(C) is a total of 100% by weight], and a polymerizable monomer component containing at least 50% by weight of methacrylic acid and methacrylic acid esters in all the components of the polymerizable monomer [however, any monomer Excluding the case of a fluorine-containing monomer] is dissolved or dispersed in a solvent, and the number average molecular weight of the copolymer (X) is 10,000.
~ 40,000 and the glass transition temperature is 20 ~ 80 ℃
A methacrylic lacquer composition characterized by being in the range of Wherein R ₁ is a hydrogen atom or a cyano group, R ₂ and R ₃ are each independently a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, X is an imino group or an oxygen atom,
Is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms or (Where R ₂ and R ₃ have the same meanings as before)] 2. The copolymer (X) has a number average molecular weight of 5,000.
The methacrylic lacquer composition according to claim 1, wherein 0 or less component is less than 10% by weight. 3. The methacrylic lacquer composition according to claim 1, wherein the other polymerizable monomer (c) contains not more than 20% by weight of styrene in all components of the polymerizable unsaturated monomer. . 4. A coating composition obtained by blending a pigment with the methacrylic lacquer composition according to any one of (1) to (3). 5. The paint according to claim 4, wherein a titanium oxide by chlorine method is essentially used as a pigment.