JPS6050223B2 - Curing method for vinyl polymers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for curing a vinyl polymer containing an acetoacetate group in the molecule, and more specifically, to a method for curing a vinyl polymer containing an acetoacetate group in the molecule, and more specifically, a method for curing a vinyl polymer containing an acetoacetate group in the molecule, and more specifically, a method for curing a vinyl polymer containing an acetoacetate group in the molecule, and more specifically, a method for curing a vinyl polymer containing an acetoacetate group in the molecule. The present invention relates to a curing method characterized in that an aluminum complex compound containing as a ligand forming a stable chelate ring is used as a curing component.

The vinyl polymer containing an acetoacetate ester group in the molecule is obtained by reacting a vinyl polymer having a hydroxyl group in the molecule with diketene in the presence of an acid-base catalyst, or by reacting a vinyl polymer having a hydroxyl group in the molecule with diketene, or By polymerizing a monomer having a polyunsaturated bond, or by polymerizing a monomer having an acetoacetate group and a polymerizable unsaturated group with another monomer having a polymerizable unsaturated group. You can also get

Although vinyl polymers generally have particularly excellent transparency and UV resistance, their uses are limited because they are thermoplastic resins. Therefore, a method has been adopted in which a curing component is blended into a vinyl polymer having a hydroxyl group in the molecule to produce a cured product with a three-dimensional structure and to further widen its use. The method involves blending amino resins such as urea resins and melamine resins with vinyl polymers that have hydroxyl groups in their molecules to create thermosetting resin compositions, which are heated at relatively high temperatures during curing. Usually 80-200
℃ temperature for about 10 to 30 minutes, which runs counter to recent demands for energy conservation.
Another curing method is to mix an isocyanate compound with a vinyl polymer having hydroxyl groups in the molecule and cure it at a relatively low temperature, usually 5 to 80°C, but in this case, generally a two-component Because the curing agent component is added immediately before use, there are problems with storage stability after adding the curing agent, and combined with the toxicity of the isocyanate compound, it is extremely inconvenient to handle. There are many points.
Transparency, without using amino resins or isocyanate compounds such as urea resin and melamine resin as mentioned above
As a method of providing a cured product with excellent UV resistance and chemical resistance, an acrylic polymer having an epoxy group or a hydroxyl group is added to an acrylic polymer having an epoxy group or a hydroxyl group in the molecule, and a carbonyl group or a hydroxyl group is added to the central metal valence and coordination number at the β position. A curing method is known in which an intramolecular compound completely satisfied by a carboxylic acid ester having a group is incorporated as a curing agent component (Japanese Patent Publication No. 45-9073). However, even with this curing method, it is generally necessary to heat treat 10 to 3 powders at 150°C to 180°C, and even those that harden at room temperature cannot be cured in an organic solvent such as alcohol or cellosolve. If the membrane is immersed, there are disadvantages such as a large portion of the membrane being dissolved in the solvent.

In view of the above, there has been a strong desire to develop a method for curing vinyl polymers at room temperature, which is one-component and free from toxicity concerns.

The present inventor has developed a method of making a one-component vinyl polymer and curing it while drying at room temperature to obtain a coating film with excellent transparency, ultraviolet resistance, chemical resistance, solvent resistance, and various physical properties. As a result of research, we added aluminum alcoholates or compounds capable of forming keto-enol tautomers as curing components to vinyl polymers having acetoacetate groups in the molecule as ligands that form stable chelate rings. The present invention has been completed by discovering a curing method characterized by using an aluminum complex compound containing the compound as a curing component. That is, the present invention is characterized in that an aluminum complex compound containing an aluminum alcoholate or a compound capable of forming a keto-enol tautomer as a ligand for forming a stable chelate ring is used as a curing component. The present invention relates to a method for curing vinyl polymers containing acetoacetate groups in the molecule.

An aluminum complex compound containing an aluminum alcoholate or a compound capable of forming a keto-enol tautomer as a ligand forming a stable chelate ring has the general formula A1(0R)n(L)3-.

(However, R represents an alkyl group, L represents a compound capable of forming a keto-enol tautomer, and n represents an integer of 0 to 3.

). Alkyd resins, epoxy resins, phenolic resins, vinyl polymers containing hydroxyl groups and/or carboxyl groups in the molecule can be It is known to be used as a curing agent for coalescence, but as in the present invention, by blending these as a curing agent into a vinyl polymer containing an acetoacetate group in the molecule, transparency and durability can be improved. There is still no known method for obtaining a coating film with excellent UV resistance, chemical resistance, solvent resistance, and various physical properties.

The details of the mechanism of the curing method of the present invention are unknown, but by drying, i.e., solvent volatilization, the vinyl polymer containing an acetoacetate group is coordinated with an aluminum alcoholate or a compound capable of keto-enol tautomerism. It is thought that the curing occurs because a ligand exchange reaction occurs with the aluminum complex compound contained as a child, resulting in crosslinking.

In vinyl polymers containing acetoacetate groups,
In addition to the acetoacetate group, a hydroxyl group or a carboxyl group may be contained. (In the case of hydroxyl groups, crosslinking occurs by alkoxide bonds, and in the case of carboxyl groups, crosslinking occurs by acylate bonds.) The vinyl polymer containing an acetoacetate group that can be used in the present invention is a vinyl polymer having a hydroxyl group and a diketene polymer. Diketene is obtained by reacting with Mp-6 in the presence of an acid-base catalyst.
．． 5°C, Bpl27.4°C, N3l. 4379, City 81
．． 0897, vapor pressure (20, C) 8.0 nm, colorless liquid with lachrymatory and strong pungent odor.

(A.B.BOese,.Ind,, Eng.Chem
．． ,? 16 (1940)) As acid-base catalysts, hydrochloric acid,
Acidic catalysts such as trichloroacetic acid, dichloroacetic acid, monochloroacetic acid, acetic acid, formic acid, phthalic anhydride, cobalt nitrate, and valatoluenesulfonic acid, or basic catalysts such as sodium acetate and potassium acetate can be used. The reaction between a vinyl polymer having a hydroxyl group and diketene is carried out in an organic solvent without active hydrogen groups, such as ketones, esters, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, or a mixed solvent thereof. It is obtained by dissolving a vinyl polymer having a hydroxyl group in the solution, adding the acid-base catalyst described above to this solution, adding diketene with stirring, and keeping at room temperature to 70°C for 1 to 10 hours.

The amount of the acid-base catalyst added is 0.01 to 1 part by weight, preferably 0.1 to 1 part by weight, per 100 parts by weight of the vinyl polymer having hydroxyl groups. Diketene is added at a rate of 1 mol per 1 mol of hydroxyl groups in the vinyl polymer having hydroxyl groups, but if the hydroxyl groups are left, it may be added at a rate of 1 mol or less. However, it is necessary that the vinyl polymer contains 5 mol% or more of acetoacetate groups. The above-mentioned vinyl polymer having a hydroxyl group that reacts with diketene can be obtained as follows.

That is, polymerizing a monomer having a hydroxyl group and a polymerizable unsaturated bond, or polymerizing a monomer having a hydroxyl group and a polymerizable unsaturated bond with another monomer having a polymerizable unsaturated bond. A vinyl polymer having a hydroxyl group is obtained by this method. Monomers having a hydroxyl group and a polymerizable unsaturated bond include 2-hydroxyethyl methacrylate,
2-hydroxyethyl acrylate, 2-methacrylate
-Hydroxyfukomavir, 2-hydroxypropyl acrylate, allyl alcohol, 3-chloro-2-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, polyethylene glycol monomethacrylate (general formula is CH2- -9-0(CH2
CH2O)NHn=5-6), polypropylene glycol monomethacrylic route (general formula CH2- and -C-O/C
H2 and HO)NHn=5-6), etc. can be used. Other monomers having polymerizable unsaturated bonds are those used to adjust the number of functional groups of hydroxyl groups in vinyl polymers, and include, for example, styrene, vinyl toluene, and N-vinylpyrrolidone. , acrylic esters,
Included are methacrylic esters, itaconic esters, maleic esters, fumaric esters, crotonic esters, acrylonitrile, methacrylonitrile, and the like.

It is also possible to use polymerizable unsaturated carboxylic acids such as methacrylic acid, fumaric acid, acrylic acid, maleic acid, crotonic acid, and itaconic acid, but the amount used is 10 mol% or less of the total monomers. preferable. In addition, as mentioned above, vinyl polymers containing acetoacetate groups in the molecule can be produced by reacting vinyl polymers having hydroxyl groups with diketene, as well as acetoacetate groups and polymerizable inorganic compounds. Also by polymerizing a monomer having a saturated bond, or by polymerizing a monomer having an acetoacetate group and a polymerizable unsaturated bond with another monomer having a polymerizable unsaturated bond. can get.

Other monomers having a polymerizable unsaturated bond are as described above, but the monomer having an acetoacetate group and a polymerizable unsaturated bond is different from the monomer having a hydroxyl group and a polymerizable unsaturated bond. It is obtained by reacting diketene with diketene in the presence of an acid-base catalyst. Examples of the monomer having a hydroxyl group and a polymerizable unsaturated bond, and the acid-base catalyst are as described above.
The end points of the reaction between a vinyl polymer having a hydroxyl group and diketene and the reaction between a monomer having a hydroxyl group and a polymerizable unsaturated bond and diketene were determined from infrared spectra. In other words, an acetoacetate group is obtained by the reaction between a hydroxyl group and diketene, and the absorption of the ester group and ketocarbonyl group of this acetoacetate group is 1, respectively.
Appears at 750 and 1710 cm-1. This 1710c
7rL-1 overlaps with the absorption of acrylic ester and methacrylic ester, but the absorption of 1750d-1 can be clearly distinguished. Also, although the absorption is weak, it is 1610c7! -1
absorption is caused by the formation of a CC double bond in the enol. It is recognized that this appears as a shoulder of the 1630-1640c1n-1 absorption of acrylic esters and methacrylic esters. Therefore, the end point of the reaction between hydroxyl group and diketene is 1750 cm- in the infrared spectrum.
It was considered that the change in the absorption of 1 and the absorption of 1610c7n-1 disappeared and reached the maximum. (The completion of the reaction was confirmed by infrared spectroscopy in the examples based on the above-mentioned idea and method.) Next, a compound capable of forming an aluminum alcoholate or a keto-enol tautomer was stabilized. An aluminum complex compound contained as a ligand forming a chelate ring will be described.

Examples of aluminum alcoholates include aluminum trimeth B oxide, aluminum triethoxide, aluminum tri-n-propoxide, aluminum-1-propoxide, aluminum tri-n-butoxide, aluminum-1-butoxide, aluminum-Sec-butoxide, and aluminum-Tert. -butoxide, etc., and particularly preferred results are obtained when aluminum triisopropoxide, aluminum-Sec-butoxide, aluminum-n-butoxide, etc. are used. Compounds that can form keto-enol tautomers include β-diketones (acetylacetone, etc.), acetoacetic esters (methyl acetoacetate, etc.), malonic acid esters (ethyl malonate, etc.), and Ketones with a hydroxyl group (
diacetone alcohol, etc.), aldehydes having a hydroxyl group at the β position (such as salicylaldehyde), and esters having a hydroxyl group at the β position (such as methyl salicylate). In particular, suitable results can be obtained by using acetoacetic acid esters and β-diketones. By mixing these compounds with alcoholates in a molar ratio of 1:4 or less, aluminum complex compounds that can be used as hardening components can be prepared as desired. As already mentioned, the curing method of the present invention involves coordinating a vinyl polymer containing an acetoacetate group with a compound capable of forming an aluminum alcoholate or a keto-enol tautomer to form a stable chelate ring. This is accomplished by using an aluminum complex compound as a hardening component. The amount of curing components for vinyl polymers containing acetoacetate groups, that is, aluminum alcoholates and aluminum complex compounds, depends on the concentration of acetoacetate groups, as well as aluminum, L, and aluminum extraction.
When the gel fraction of the coating film cured by the curing method was measured, the gel fraction was 50 to 100%. It was confirmed that curing was achieved.

In addition, in order to improve the storage stability of a system in which aluminum alcoholates and aluminum complexes are added to a vinyl polymer containing an acetoacetate group, alcohols such as methanol, ethanol, and 1-propanol are added to this system. , cellosolve, butyl cellosolve, and other cellosolves may be added as appropriate.

Next, the present invention will be explained according to examples.

Example 1 500m equipped with thermometer, stirrer, cooler and drip load
Put 50y each of toluene and n-butyl acetate into a 14-fluoro round bottom flask, and after replacing the air with nitrogen gas,
It was heated to 00'C.

When the temperature became constant, a mixed solution consisting of 30 y of styrene, 20 y of methyl methacrylate, 30 y of butyl acrylate, 20 q of 1-2-hydroxyethyl methacrylate, and 1 q of azobisisobutyronitrile as a polymerization initiator was added dropwise over 2 hours. Ta. The polymerization rate reached almost 100% 5 hours after dropping. Viscosity Y (Gardner viscometer, 2
All viscosities below 5°C are determined by this method. ) Non-volatile content 50
% of a colorless and transparent resin solution is obtained.2 Um alcoholate and aluminum complex compounds are determined by the type of compound, so they cannot be uniformly defined, but in general, resin solids of vinyl polymers. 1-5 parts by weight, preferably 2-2 parts by weight, of aluminum alcoholates and aluminum complex compounds are added to 100 parts by weight.
To check the degree of hardness, aluminum alcoholates and aluminum complex compounds were added to a vinyl polymer containing acetoacetate groups, and after coating on a glass plate, the mixture was kept at a constant temperature of 25°C and 65% RH. Leave it in a humid room, peel off a part (about 1y) after a certain period of time, cut it into strips, wrap it in a 200 mesh stainless wire mesh, and soak it in boiling acetone/i-propyl alcohol 1/1. The acetone soluble part was extracted by soaking for 8 hours, and the extracted residue was immersed for 8 hours.
The gel fraction was measured by drying at 5° C. for 3 hours.

Calculation formula 100 It was.

This is referred to as a resin solution (1). Next, add 2
00y resin solution (1) is taken and heated to 50-60'C.

When the temperature became almost constant, 12.9y of diketene
0.05y of sodium acetate (anhydrous) and 12.9y of methyl ethyl ketone are added into the reaction vessel. Shortly after the addition, an infrared spectrum was measured and it was confirmed that the reaction had completed. At this point, a light reddish-brown clear resin solution was obtained with a viscosity x (Gardner viscometer, 25° C.) of 50% non-volatile content. This resin solution having an acetoacetate group is referred to as a resin solution (2). Next, 100q of this resin solution (2) was added with aluminum
5y of a curing agent (referred to as curing agent (1)) obtained by mixing 100q of butoxide and 1301 q of acetylacetone was added. The obtained resin composition has a viscosity of Z and a temperature of 50
It was very stable without showing any increase in viscosity during a 7-day storage stability test at °C. This composition was applied on a glass plate (so that the film thickness was 20 to 30 μm after drying) and left in a constant temperature and humidity room at 25°C and 65RH.
After 24 hours, the gel fraction described above was measured.

The results are listed in Table 1. In addition, the nonvolatile content (a) of this composition
rutile-type titanium oxide from Shunbu was added to the mixture and kneaded with three rolls to obtain white enamel.

This white enamel was diluted to an appropriate viscosity, sprayed onto a phosphate-treated steel plate, and dried at room temperature (20'C) for 24 hours. The properties of the resulting coating film are listed in Table 2. Example 2 100 y of aluminum triisopropoxide and 1 y of acetoacetic acid ethyl ester were added to 100 y of the resin solution (1) of Example 1.
The resin composition obtained by adding curing agent 10y mixed with 90q had a viscosity of Z and had excellent storage stability like the composition of Example 1.

As in Example 1, the gel fraction and white enamel performance were investigated and listed in Tables 1 and 2, respectively. Example 3 First, 100 y of 1-2-hydroxyethyl acrylate was placed in the same reaction vessel as in Example 1 and heated to 60 to 700C.

When the temperature becomes constant, add sodium acetate (anhydrous) to 0.
．． 1y is added followed by diketene dropwise over 2 hours. (Please be careful as the heat generation is intense.) Two hours after the completion of the dropwise addition, it was confirmed from the infrared spectrum that the reaction had completed. The monomer obtained by this reaction is called monomer (1).

Next, 50 I1 each of xylene and butyl acetate were placed in the same reaction vessel as in Example 1, heated to 1000 C, and when the temperature became constant, 20 I of styrene and 20 I1 of methyl methacrylate were added.
0y1 n-butyl methacrylate 30y1 The above monomer (
1) A mixed solution consisting of 30y and 0.5y of lauryl peroxide as a polymerization initiator was dropped over 3 hours.

The polymerization rate reached almost 100% 6 hours after dropping. Viscosity Z
-2, a pale yellow transparent resin solution with a non-volatile content of 50% was obtained. This is referred to as a resin solution (3). This resin solution (3
) 100y, 3y of aluminum tri-Sec-butoxide and 20y of isopropyl alcohol were added to obtain a resin composition having a viscosity W and a non-volatile content of 41%.

Regarding this composition, the gel fraction and performance with white enamel were examined in the same manner as in Example 1, and the results are shown in Tables 1 and 2, respectively. Example 4 5 xylene and butyl acetate were placed in the same reaction vessel as in Example 1.
When the temperature becomes constant, add 20q1 styrene, 20g ethyl methacrylate, 38g butyl acrylate, 2y1 methacrylic acid, 20y of the above monomer (1) and tert-butyl peroxybenzoate as a polymerization initiator. Mixed liquid consisting of 0.5y 3
It was allowed to drip over a period of time.

The polymerization rate reached almost 100% 6 hours after dropping. Viscosity Z
-3, a pale yellow transparent resin solution with a non-volatile content of 50% was obtained. This is referred to as a resin solution (4). This resin solution (4)
10y of the curing agent (1) of Example 1 was added to 100y.
The resulting resin composition had a viscosity of Z-3. Regarding this resin composition, the gel fraction was measured in the same manner as in Example 1, and various performances of the white enamel were also investigated, and the results are listed in Tables 1 and 2, respectively. Comparative Example 1 Example 1 was added to the resin solution (1) 1009 obtained in Example 1.
5g of curing agent (1) was added.

Claims (1)

[Claims] 1. An aluminum complex compound containing an aluminum alcoholade or a compound capable of forming a keto-enol tautomer as a ligand forming a stable chelate ring is used as a curing component. A method for curing a vinyl polymer containing an acetate group.