JPS6315311B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a urethane coating composition with excellent initial curing properties. Compared to polyester urethane paints, acrylic urethane paints are lighter in color, require less curing agent, and are superior in terms of weather resistance, hardness, thinner resistance, mechanical properties, etc., so the demand for them is increasing year by year. . However, for applications that require fast curing properties such as woodworking, plywood, building exteriors, automobile repair, and inorganic materials, there is currently no product that has good curing properties even though the physical properties are sufficient. be. By the way, conventionally known methods for improving curing properties include, for example, using unsaturated acid monomers, externally adding organic metal salt compounds such as zinc octylate and dibutyltin dilaurate, and using amines. There are methods to add externally, but there are issues such as compatibility with pot life, problems with weather resistance and decrease in chemical resistance, problems with controlling the amount added, problems with elution or migration, problems with odor and coloration, etc. Each one has its own advantages and disadvantages, making it difficult to use them to their full potential. In view of this situation, the present inventors conducted extensive research and found that the above-mentioned drawbacks could be improved by introducing a polymerizable organic tin compound into the copolymer, leading to the present invention. That is, the present invention provides ``(1) Polymerizable organic tin compound
0.0001 to 10% by weight (hereinafter abbreviated as %) (2) Hydroxyl group-containing polymerizable monomer 5 to 50% (3) Polymerizable monomers other than (1) and (2) 100−{(1)+ (2)} OH/OH/polyisocyanate to a polymer consisting of
A coating composition with excellent initial curing properties obtained by blending NCO = 1/0.5 to 1/1.5 (equivalent ratio). ” related. The polymerizable organic tin compound used in the present invention includes:
Tin salts of polymerizable carboxylic acids are preferred, e.g.
These include dibutyl tin malate, dioctyl tin malate, dibutyl tin laurate malate, dibutyl tin fumarate, dibutyl tin octate malate, tributyl tin (meth)acrylate, diphenyl tin methacrylate, and the like. The amount to be used is selected based on the expected balance between initial curing properties and pot life.
%, preferably 0.001 to 5%. Hydroxyl group-containing polymerizable monomers include (i) β-hydroxyethyl (meth)acrylate, β-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, Metac E, and P
(Meta) containing hydroxyl groups such as (NOYU Chemical Co., Ltd.)
Acrylic acid derivatives, (ii) Cardiula E (Ciel Chemical Co., Ltd.
Co., Ltd.), monoepoxy compounds represented by monoglycidyl esters of monovalent carboxylic acids such as octylic acid glycidyl ester and coconut oil fatty acid glycidyl ester, and monoglycidyl ethers such as butyl glycidyl ether, (meth)acrylic acid, and fumaric acid. , an adduct with a carboxyl group-containing monomer such as maleic acid, and (iii) a low molecular weight polyester resin having a polymerizable unsaturated group. If the amount used is less than 5%, sufficient physical properties will not be obtained, and if it exceeds 50%, it is undesirable in terms of paint price. Therefore, a range of 5 to 50%, particularly 10 to 40% is preferred. Polymerizable monomers other than components (1) and (2), which are component (3), include styrene compounds such as styrene and α-methylstyrene; methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylic acid derivatives such as (meth)acrylate, isobutyl (meth)acrylate, and glycidyl (meth)acrylate; (meth)acrylic acid;
Polymerizable unsaturated acids such as fumaric acid, maleic acid, itaconic acid, β-acid phosphooxy (meth)acrylate; diester of maleic acid or fumaric acid with _C1 - _C8 monohydric alcohol, (meth)acrylamide , dialkylaminoalkyl (meth)acrylate, N-alkoxymethyl (meth)acrylamide, and the like. These ingredients are
The amount of each component (1) and (2) used determines the amount used, but they may be used in an appropriate combination depending on the desired physical properties of the coating film. Among these polymerizable monomers, unsaturated acids and dialkylaminoalkyl (meth)acrylates have the effect of accelerating the curing reaction with polyisocyanate, but also have the effect of improving adhesion to other substrates. ing. When used in the present invention,
Rather, I use it expecting the latter effect,
It is preferable to keep the amount used within a very small range of 0.05 to 5%. In addition, when using styrene compounds, the physical properties of the coating film, durability, sharpness,
In terms of compatibility with other resins, the amount used is 1
It is preferable to keep it within the range of ~40%, especially 1~30%. Nitrogen-containing monomers other than dialkylaminoalkyl (meth)acrylates, such as (meth)acrylamide and N-alkoxymethyl (meth)acrylamide, have problems such as turbidity, durability, storage stability, and tendency to thicken during reaction. From this point of view, when using these substances, the amount used should be 0.5 to 15%.
It is desirable to keep it to a certain extent. Since (meth)acrylic acid derivatives have relatively few disadvantages as described above, there are no particular limitations, and several types may be used in an appropriate combination depending on the desired physical properties of the coating film. In addition, a polymer obtained by using a combination of n-butyl methacrylate and a diester of maleic acid or fumaric acid and a C ₁ to C ₈ monohydric alcohol, such as (1) polymerizable organic tin compound 0.0001 to 10% (2 ) Hydroxyl group-containing polymerizable monomer 5-50% (3) n-butyl methacrylate 20-90% (4) Diester of maleic acid or fumaric acid and _C1 - _C8 monohydric alcohol 0.1-25% (5 ) Copolymerizable monomers other than (1) to (4)
The product obtained from 100-{(1)+(2)+(3)+(4)}% has not only excellent initial curing properties but also excellent paint workability, solid appearance, etc., and is resistant to yellowing and deterioration due to ultraviolet rays. It is possible to provide a coating composition with less At this time, the mechanism by which UV resistance is improved by using more than a certain amount of n-butyl methacrylate is not well understood, but in terms of physical properties, due to the properties held by this monomer, it is possible to reduce viscosity by improving solubility. A coating film with high toughness and toughness can be obtained, resulting in improved resistance to cracking. If the amount used is less than 20%, no noticeable effect will be obtained, and if it is more than 90%, undesirable effects may occur in terms of physical properties of the coating, such as a decrease in solvent resistance, gasoline resistance, and stain resistance. Therefore, the amount to be used is preferably 20 to 90%, particularly in the range of 30 to 80%, considering the effect and physical properties of the coating film. Also, maleic acid or fumaric acid
Diesters with C ₁ to C ₈ monohydric alcohols include maleic acid, fumaric acid and C ₁ to C ₈ monohydric alcohols,
For example, dibutyl fumarate and diisobutyl fumarate are particularly recommended because of their copolymerizability with methanol, ethanol, propanol, butanol, etc., storage stability as a monomer, and physical properties of the coating film. By using this component, it is possible to lower the viscosity without using chain transfer agents such as mercaptans, which have a negative effect on weather resistance, and it is possible to expect a substantial increase in solidity. . If it is less than 0.1%, no effect can be obtained, and if it exceeds 25%, it may remain in the resin solution in the form of a free monomer due to its copolymerizability, which is not preferable. accordingly
A range of 0.1 to 25%, particularly 5 to 15% is preferred. Thus, the obtained polymer has n (number average molecular weight)
= 1000 to 8000, especially 2000 to 7000; w (weight average molecular weight)/n = 1.7 to 3.7, especially 1.9 to 3.7; Tg (glass transition point) = -10 to 60°C, preferably 0 to 50°C . If n of the polymer is 1000 or less,
It is easy to sag, and the physical properties of the paint film are not good enough, and if you want to achieve it, you have to increase the OH value, which is not desirable because the paint film becomes brittle and the price of the paint increases. When n is 8000 or more, there are no problems with the physical properties of the coating, but defects appear in the appearance of the coating, uneven metal return, skin, gloss, texture, etc. The w/n ratio expresses the behavior of molecular weight distribution and is related to the difficulty of separating from the solvent.W/n<1.7 is effective in improving the separation from the solvent, but in the currently known solution polymerization method, It's quite difficult, but on the other hand, w/
When Mn>3.7, solvent removal becomes difficult and there are many disadvantages such as poor painting workability, uneven return of metal, gloss, and texture, which is not preferable. The Tg of the polymer can be calculated, for example, using Fox's formula; 1/Tg=Wi/Tgi (Tgi, Wi: Tg of component i, weight fraction). If Tg is -10℃ or less, flexibility,
Although it has excellent mechanical properties such as crack resistance and impact resistance due to repeated exposure to cold and heat, it is inferior in terms of stain resistance, solvent resistance, constant blocking property, etc. Mechanical properties are reduced, and stain resistance, solvent resistance, blocking resistance, etc. are improved. The polyisocyanates used in the present invention include aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexane diisocyanate; isophorone diisocyanate, methyl Cyclohexane-2,4 (or 2,6)-diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,3
- (Methyl isocyanate) A compound having a functional group that reacts with an alicyclic diisocyanate such as cyclohexane and a polyhydric alcohol or isocyanate group such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, etc. Low molecular weight polyester resins (including oil-modified types), adducts with water, etc., polymers, diisocyanate polymers (oligomers), or known blocking of these with lower monohydric alcohols, methyl ethyl ketoxime, etc. Suitable products are those blocked with a chemical agent, and commercially available examples include Burnock D-750, D-800, DN-950, DN-970,
D-500, D-550 (Dainippon Ink Chemical), Takenate D-102, D-110N, D-120N, D-140N,
B-420S (Takeda Pharmaceutical), Coronate L, HL, 2030
(Japan Polyurethane), Desmodeleur L, N,
Examples include HL (Bayer AG). In particular, those other than aromatic diisocyanates that do not yellow due to ultraviolet rays are preferred. In the present invention, the blending ratio of the above polymer and polyisocyanate is OH/NCO = 1/0.5 to 1/1.5 (equivalent ratio), and if NCO is less than 0.5 equivalent to 1 equivalent of OH, a sufficient coating film is obtained. Physical properties cannot be obtained, and if the amount exceeds 1.5 equivalents of NCO per 1 equivalent of OH, the physical properties of the coating film will be sufficient, but the price of the paint will be high. Solvents that can be used to obtain the polymer of the present invention include aromatic hydrocarbons such as toluene and xylene, acetate ester solvents such as ethyl acetate, butyl acetate, and cellosolve acetate, and ketone solvents such as MEK and MIBK. Any material normally used for urethane paints can be used. The initiator used for polymerization can be one that is normally used for polymerizing acrylic monomers, such as AIBN, BPO, ditertiary butyl peroxide, and the polymerization method can be any known solution polymerization method. . The paint thus obtained can be used both as a clear paint and as an enamel paint. It can be used in a wide range of applications, including wood coatings, plywood coatings, automobile repair coatings, plastic coatings, architectural exterior coatings, and inorganic material coatings.
In addition, if necessary, known paint additives such as leveling agents, antifoaming agents, and anti-slip agents, or cellulose compounds such as nitrocellulose and CAB,
It is also possible to blend a small amount of other resins, such as vinyl resins, silicone resins, amino resins, polyester resins, and other acrylic resins, within a range that is compatible with the present polymer. Regarding the coating and curing conditions, commonly used methods such as spray coating, electrostatic coating, brush coating, room temperature drying, forced drying, and baking drying can be applied. Next, the present invention will be explained with reference to examples, but the present invention is not limited thereby, and parts in the examples indicate parts by weight. Example 1 Add xylene to a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and inert gas inlet.
500 parts and 200 parts of butyl acetate were charged, and the temperature was raised to 120°C. When the temperature reaches 120℃, 300 parts of styrene, 330 parts of methyl methacrylate, 120 parts of butyl acrylate,
Consisting of 50 parts of ethyl acrylate, 190 parts of β-hydroxyethyl methacrylate, 10 parts of dibutyltin laurate malate, 20 parts of tert-butyl peroctoate, 5 parts of di-tert-butyl peroxide, 5 parts of AIBN, and 300 parts of butyl acetate. The mixture was added dropwise over 5 hours, and after the addition was completed, it was kept at 120°C for about 10 hours until the non-volatile content was 50.3% and the viscosity was
A resin solution with Y, acid value 1.0, color number <1, and OH value 40 was obtained. 100 parts of the obtained resin solution, 24 parts of Burnock DN-950 (manufactured by Dainippon Ink Chemical Co., Ltd.) as polyisocyanate (OH of resin/polyisocyanate)
Equivalence ratio of NCO = 1) and acid value titanium (R-CR
-3: Diluted 36.6 parts (manufactured by Britain Titanium Co., Ltd.) with a mixed solvent of xylene/toluene/butyl acetate/ethyl acetate/cellosolve acetate = 20/50/15/10/5 weight ratio in an Iwata cup for 14 to 15 seconds. and got the paint. The physical properties of this paint are shown in Table 1. Example 2 Add 500 g of xylene to the same four-necked flask as in Example 1.
and 200 parts of butyl acetate, and the temperature was raised to 120°C. When the temperature reaches 120℃, 650 parts of methyl methacrylate,
150 parts of butyl acrylate, 140 parts of β-hydroxyethyl methacrylate, 7 parts of methacrylic acid, 48 parts of ethyl acrylate, 5 parts of dibutyl tin malate
25 parts of tertiary butyl peroctoate, 5 parts of ditertiary butyl peroxide, 6 parts of AIBN,
A mixture consisting of 300 parts of butyl acetate was added dropwise over 5 hours, and after the addition was completed, it was kept at 120°C for about 10 hours.
Nonvolatile content 51.0%, viscosity W, acid value 2.3, number of colors <1,
A resin solution with an OH value of 30 was obtained. 100 parts of the resulting resin solution, Burnock DN-950
A coating material was obtained in the same manner as in Example 1 using 18 parts (OH/NCO equivalent ratio = 1) and 34.2 parts of titanium oxide (R-CR-3). The physical properties of this paint are shown in Table 1. Comparative Example 1 Monomer mixture: 300 parts of styrene, 330 parts of methyl methacrylate, 130 parts of butyl acrylate
parts, 190 parts of β-hydroxyethyl methacrylate,
Same as Example 1 except that 50 parts of ethyl acrylate was used, non-volatile content 50.5%, viscosity X, acid value 0.9,
A resin solution with a color number <1 and an OH value of 40 was obtained. Hereinafter, a paint was obtained in the same manner as in Example 1. The physical properties of this paint are shown in Table 1. Comparative Example 2 Methyl methacrylate as monomer mixture
650 parts, butyl acrylate 150 parts, β-hydroxyethyl methacrylate 140 parts, methacrylic acid 7
53 parts of ethyl acrylate was used, but in the same manner as in Example 2, the non-volatile content was 50.6%, the viscosity Y, and the acid value.
A resin solution with a color number of 2.2, color number <1, and an OH value of 30 was obtained. Thereafter, a paint was obtained in the same manner as in Example 2. The physical properties of this paint are shown in Table 1.

[Table] (Test conditions) The coating film used in each physical property test was a 38-40μ film obtained by applying the paint to a tin plate (BN#144 treated steel plate) using air spray and baking it at 70℃ for 30 minutes. I used a thick one. However, drying (23℃): After applying the paint to the tin plate,
4 sheets of gauze are stacked at regular intervals without baking at 23°C, a 100g weight is placed on top of the gauze, and the gauze is left for 1 minute to determine the gauze marks left on the coating. Example 3 650 parts of n-butyl methacrylate, 50 parts of styrene
100 parts of a monomer mixture consisting of 100 parts of dibutyl fumarate, 0.1 part of dibutyl tin malate, 90 parts of methyl methacrylate, 9.9 parts of methacrylic acid, and 100 parts of β-hydroxyethyl methacrylate was prepared. In the same four-necked flask as in the production example, add 150 parts of the monomer mixture, 150 parts of toluene, 388 parts of butyl acetate,
Charge 3 parts of tertiary butyl perbenzoate and raise the temperature to 118°C. Once it reaches 118°C, add 850 parts of the monomer mixture prepared earlier, 280 parts of toluene,
10 parts of AIBN, ditertiary butyl peroxide
A mixture of 10 parts of tert-butyl peroctate and 30 parts of tert-butyl peroctate was added dropwise over 6 hours, and 120 parts of
The temperature was raised to ℃ and held for 10 hours. Non-volatile content 54.9%,
Viscosity W, OH value 26, acid value 4.0, n=6000, w/
A resin solution with Mn=3.2 and Tg=32°C was obtained. 100 parts of the resulting resin solution, Burnock DN-950
A coating material was obtained in the same manner as in Example 1 using 15.6 parts (OH/NCO equivalent ratio = 1) and 35.9 parts of acid value titanium (R-CR-3). The physical properties of this paint are shown in Table 2. Example 4 550 parts of n-butyl methacrylate, 55 parts of styrene
parts, dibutyl fumarate 45 parts, dibutyl tin laurate malate 0.5 parts, methyl methacrylate
99.5 parts, 10 parts of methacrylic acid, 140 parts of β-hydroxyethyl methacrylate, 100 parts of butyl acrylate
1000 parts of a monomer mixture consisting of 1000 parts were prepared. 100 parts of xylene and 337 parts of butyl acetate were placed in the same four-necked flask as in the production example, and the temperature was raised to 120°C.
Then, 1000 parts of the monomer mixture prepared earlier,
A mixture consisting of 230 parts of xylene, 15 parts of AIBN, 10 parts of ditertiary butyl peroxide, and 40 parts of tertiary butyl peroctate was added dropwise over 7 hours, and then maintained at 120° C. for 10 hours. Non-volatile content
59.6%, viscosity UV, OH value 38, oxidation 4.2, n=
5100, w/n=3.1, and Tg=26°C, a resin solution was obtained. 100 parts of the resulting resin solution, Burnock DN-950
A coating material was obtained in the same manner as in Example 1 using 22.8 parts (OH/NCO equivalent ratio = 1) and 41.5 parts of titanium oxide (R-CR-3). The physical properties of this paint are shown in Table 2. Example 5 480 parts of n-butyl methacrylate, styrene
150 parts, dibutyl fumarate 80 parts, dibutyltin malate 0.1 part, methyl methacrylate 60 parts, β
- 1000 parts of a monomer mixture consisting of 190 parts of hydroxyethyl methacrylate, 25 parts of isobornyl methacrylate, and 14.9 parts of acrylic acid was prepared. Charge 100 parts of xylene and 200 parts of butyl acetate into a four-necked flask and raise the temperature to 120°C. Once the temperature reaches 120°C, 1000 parts of the monomer mixture prepared earlier, 230 parts of xylene,
A mixture consisting of 138 parts of butyl acetate, 25 parts of AIBN, 10 parts of tertiary butyl peroxide, and 50 parts of tertiary butyl peroctate was added dropwise over 7 hours, and then maintained at 120°C for 10 hours. Non-volatile content 60.1
%, viscosity S, OH value 50, acid value 6.3, n=3500,
A resin solution with w/n=2.6 and Tg=42°C was obtained. 100 parts of the resulting resin solution, Burnock DN-950
A coating material was obtained in the same manner as in Example 1 using 30 parts (OH/NCO equivalent ratio = 1) and 44.4 parts of titanium oxide. The physical properties of this paint are shown in Table 2. Comparative Example 3 Styrene was used as the monomer mixture in Example 3.
50 parts of dibutyl fumarate, 486 parts of methyl methacrylate, 10 parts of methacrylic acid, 100 parts of β-hydroxyethyl methacrylate, and 254 parts of butyl acrylate in the same manner as in Example 1,
Non-volatile content 54.8%, viscosity X, OH value 26, acid value 4.0,
A resin solution with n=6000, w/n=3.2, and Tg=32°C was obtained. Hereinafter, a paint was obtained in the same manner as in Example 3. The physical properties of this paint are shown in Table 2. Comparative Example 4 Same as Example 2 except that 50 parts of styrene, 100 parts of dibutyl fumarate, 405 parts of methyl methacrylate, 10 parts of methacrylic acid, 140 parts of β-hydroxyethyl methacrylate, and 295 parts of butyl methacrylate were used in Example 4. Non-volatile content 60.2%, viscosity V
~ ^W2 , OH value 38, acid value 4.1, n=5100, w/
A resin solution with Mn=3.1 and Tg=26°C was obtained. Thereafter, a paint was obtained in the same manner as in Example 4. The physical properties of this paint are shown in Table 2. Comparative Example 5 In Example 5, the monomer mixture was 50 parts of n-butyl methacrylate, 150 parts of styrene, 80 parts of dibutyl fumarate, 190 parts of β-hydroxyethyl methacrylate, 15 parts of acrylic acid, 317.5 parts of methyl methacrylate, and butyl acrylate. 172.5
59.8% non-volatile content, viscosity T, OH value 50, acid value 6.4, n = 3500, w/n.
= 2.6, a resin solution with Tg = 42°C was obtained. Thereafter, a paint was obtained in the same manner as in Example 5. The physical properties of this paint are shown in Table 2.

【table】

Claims (1)

[Scope of Claims] 1 (1) Polymerizable organic tin compound 0.0001 to 10% by weight (2) Hydroxyl group-containing polymerizable monomer 5 to 50% by weight (3) Polymerizable monomers other than (1) and (2) Quantity
100−{(1)+(2)}% by weight of polyisocyanate in OH/
A coating composition that is blended so that NCO=1/0.5 to 1/1.5 (equivalent ratio).