JPS6050224B2 - Curing method for vinyl polymers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for curing vinyl polymers containing acetoacetate groups in the molecule, and more specifically, the present invention relates to a method for curing vinyl polymers containing an acetoacetate group in the molecule, and more specifically, the present invention relates to a method for curing vinyl polymers containing an acetoacetate group in the molecule, and more particularly, the present invention relates to a method for curing vinyl polymers containing an acetoacetate group in the molecule, and more specifically, a compound having the general formula or 1 to 10, R is 1 to 20 carbon atoms
A titanium complex compound containing a compound capable of forming a titanate or a keto-enol tautomer (representing an alkyl group or an alkenyl group of 2 to 20) as a ligand forming a stable chelate ring has a curing action. The present invention relates to a method of curing a vinyl polymer containing an acetoacetate group in the molecule, which is used as a component.

The vinyl polymer containing an acetoacetate group in the molecule here refers to a vinyl polymer having a hydroxyl group in the molecule and diketene reacted in the presence of an acid-base catalyst,
A monomer having an acetoacetate group and a polymerizable unsaturated bond is polymerized, or a monomer having an acetoacetate group and a polymerizable unsaturated bond/bond and another monomer having a polymerizable unsaturated group It can also be obtained by polymerizing.

Although vinyl polymers generally have particularly excellent transparency and UV resistance, their use is 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, which can be used in a wider range of applications. The method involves blending vinyl polymers with hydroxyl groups in their molecules with urea resins, melamine resins, and other amide resins to create thermosetting resin compositions. high temperature, usually 80-2
Requires heating for about 30 minutes at a temperature of 000C,
This goes against the recent demands for energy conservation. Another curing method is to mix an isocyanate compound with a vinyl polymer having a hydroxyl group in the molecule and cure it at a relatively low temperature, usually 5 to 80°C. Since it is used as a two-component type and the curing agent component is added immediately before use, there is a problem with storage stability after the curing agent is added, and combined with the toxicity of the isocyanate compound, it is extremely difficult to handle. There are many inconveniences. As a method to provide a cured product with excellent transparency, UV resistance, and chemical resistance without using amino resins such as urea resins and melamine resins or isocyanate compounds as described above, it is possible to add epoxy groups and hydroxyl groups within the molecule. An intramolecular complex compound in which the valence and coordination number of the central metal are completely satisfied by a carboxylic acid ester having a carbonyl group or a hydroxyl group at the β position is added to the acrylic polymer as a curing agent component. Curing methods are known.

(Japanese Patent Publication No. 45-9073) However, even in this curing method, it is generally necessary to heat-treat 10 to 3 powders at 150°C to 180'C. When a cured coating film is immersed in an organic solvent, there are drawbacks such as a large portion of the coating 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, it was found that the general formula (where n is 0 or 1 to 10 and R is 1 to 20 carbon atoms
A titanium complex compound containing a compound capable of forming a titanate or a keto-enol tautomer (representing an alkyl group or an alkenyl group of 2 to 20) as a ligand to form a stable chelate ring is used. The present invention was completed by discovering a curing method characterized by the following.

Alkyd resins, epoxy resins, titanium complex compounds containing titanates or compounds capable of forming keto-enol tautomers as ligands forming stable chelate rings.
It is known to be used as a curing agent for phenolic resins, vinyl polymers containing hydroxyl groups and/or carboxyl groups in the molecule, but as in the present invention, vinyl polymers containing acetoacetate groups in the molecule However, there is no known method to obtain a coating film with excellent transparency, ultraviolet resistance, chemical resistance, solvent resistance, and various physical properties by using these as a curing agent.

The details of the mechanism of the curing method of the present invention are unknown, but by drying, i.e., solvent volatilization, acetoacetic acid is added to a vinyl polymer containing a ster group and a general formula (where n is 0 or 1 to 10, R is carbon Numbers 1-20
or a titanium complex compound containing a compound capable of forming a keto-enol tautomer as a ligand forming a stable chelate ring. It is thought that a ligand exchange reaction takes place in the process, resulting in crosslinking, which causes curing.

In vinyl polymers containing acetoacetate groups,
In addition to the acetoacetate group, a hydroxyl group or a carboxyl group may be contained. (Crosslinking occurs by an alkoxide bond in the case of a hydroxyl group, and an acylate bond in the case of a carboxyl group.) The vinyl polymer containing an acetoacetate group that can be used in the present invention is a vinyl polymer having a hydroxyl group that is combined with a diketene. can be obtained by reacting them in the presence of an acid-base catalyst.

Diketene is Mp-6.5℃, BPI27.4℃, N3
Must. 4379, d guard 81.0897, vapor pressure (200
C) It is an 8.0 nm colorless, lachrymatory liquid with a strong pungent odor.

(A.B.BOese..Ind.Eng.Chem.
,? 16 (1940)) As acid-base catalysts, hydrochloric acid, trichloroacetic acid, dichloroacetic acid, monochloroacetic acid, acetic acid,
Acidic catalysts such as formic acid and phthalic anhydride (cobalt nitrate, 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, adding the above acid-base catalyst to this solution, adding diketene while stirring, and keeping the temperature at room temperature to 70°C for 1 hour to 1 hour.

The amount of the acid-base catalyst added is 0.01 to 1 part by weight per 10 parts by weight of the vinyl polymer having a hydroxyl group, preferably,
It is 0.1 to 1 part by weight. 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
-Hydroxypropyl, 2-hydroxypropyl acrylate, allyl alcohol, 3-chloro-2-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, polyethylene glycol monomethacrylate (general formula is CH2-d-9 −◇(CH2
CH2O)NHO=5-6), polypropylene glycol monomethacrylate (general formula is CH2-C-q-0
(CH2CHO)NHn=5-6), etc. can be used.

Further, other monomers having polymerizable unsaturated bonds are monomers used to adjust the number of functional groups of hydroxyl groups in vinyl polymers, and include, for example, styrene, vinyltoluene, N -vinylpyrrolidone, acrylic esters, methacrylic esters, itacone esters,
Included are 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 preferably 10 mol % or less based on the total amount. In addition, as mentioned above, vinyl polymers containing acetoacetate groups in the molecule can be produced by reacting a vinyl polymer having a hydroxyl group with diketene. 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 a monomer having a hydroxyl group and a polymerizable/unsaturated bond. It is obtained by reacting the 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 already mentioned 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. That is, 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 1750C77!
-1 and 1710C77! −1. This 171
0c7n-1 overlaps with the absorption of acrylic esters and methacrylic esters, but the absorption of 1750 (7t-1 is clearly distinguishable.Also, although the absorption is weak, it is at 1610 cm
The absorption of -1 appears due to the formation of a CC double bond in the eno-7-ol form. It is recognized that this appears as a shoulder of absorption at 1630 to 1640 cm-1 for acrylic esters and methacrylic esters. Therefore, the end point of the reaction between hydroxyl group and diketene is 1750c in the infrared spectrum.
There were no changes in the absorption of m-1 and 1610crf1-1, and it was considered that these absorptions had reached their maximum. (The fact that the completion of the reaction was confirmed by infrared spectra in the Examples was based on the above-mentioned idea and method.

) Next, titanates or keto enol tautomers represented by the general formula (where n is 0 or 1 to 1 and R is an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms) are added. A titanium complex compound containing a compound capable of forming a stable chelate ring as a ligand will be described.

Among the titanates represented by the above general formula, those with n=1 include tetramethyl titanate, tetraethyl titanate, tetra n-propyl titanate, and tetra IsO.
-propyl titanate, tetra tert-butyl titanate, tetra n-butyl titanate, tetra IsO-butyl titanate, tetra n-pentyl titanate, tetra n-hexyl titanate, tetra IsO-octyl titanate, tetra n-lauryl titanate, etc.
In particular, tetra IsO-propyl titanate, tetra n-
Butyl titanate, tetraIsO-butyl titanate,
Suitable results are obtained using tetra-tert-butyl titanate and the like. In addition, for those where n is 2 or more, tetra IsO-propyl titanate, tetra n-butyl titanate, tetra IsO-butyl titanate, tetra Te
Suitable results are obtained from the dimer of rt-butyl titanate having one pupil (n=2 to 10 in the above general formula). Compounds that can constitute keto-enol tautomers include β-diketones (acetylacetone, etc.), acetoacetate groups (methyl acetoacetate, etc.), malonic acid esters (ethyl malonate, etc.), Ketones with a hydroxyl group in the β position (such as diacetone alcohol), aldehydes with a hydroxyl group in the β position (such as salicylaldehyde), β
Esters having a hydroxyl group at the position (such as methyl salicylate) can be used. In particular, favorable results can be obtained using acetoacetate esters and β-diketones★
The gel fraction of the coating film cured by this curing method is A. A titanium complex compound which can be used as a hardening component can optionally be prepared by mixing the above compound in a molar ratio of up to 3 moles to the Til moles in the titanates mentioned above. As already mentioned, the curing method of the present invention is applied to a vinyl polymer containing an acetoacetate group of the general formula (where n=0 or 1 to 1, R is an alkyl group having 1 to 20 carbon atoms or 2 to A titanium complex compound containing a compound capable of forming a titanate or a keto-enol tautomer (representing an alkenyl group of 20) as a ligand forming a stable chelate ring is used as a curing component. This is accomplished by

The amount of the curing component for the vinyl polymer containing acetoacetate groups, that is, titanates and titanium complex compounds, depends on the concentration of the acetoacetate group in the vinyl polymer and the type of titanates and titanium complex compounds. Although they cannot be uniformly defined because they are determined, generally titanates and titanium complex compounds are added at 0.5 to 10 parts per 10 parts of the resin solid content of the vinyl polymer. 50 parts by weight, preferably 1 to 2 parts by weight.

To check the degree of hardening, titanates and titanium complex compounds were added to a vinyl polymer containing acetoacetate groups, and after coating on a glass plate, it was placed in a constant temperature and humidity room at 25°C and 60% RH. After leaving it for a certain period of time, a part of the paint film (
About 1f) was peeled off, cut into strips, wrapped in a 200-mesh stainless wire mesh, and boiled in acetone/Is.
The gel fraction was measured by immersing the sample in a 1/1 weight ratio of O-propyl alcohol for 8 hours, extracting the acetone-soluble portion, and drying the extracted residue at 105° C. for 3 hours.

When the calculation formula was measured, it was found that the gel fraction was 50-100%, indicating that curing was completed.

The properties of titanates and titanium complex compounds are similar to those of aluminum complex compounds containing compounds capable of forming aluminum alcoholates or keto-enol tautomers as ligands to form stable chelate rings, respectively. However, titanates and titanium complex compounds have better storage stability.

However, in order to improve the storage stability of the yoso layer, titanates and titanium complex compounds are added to vinyl polymers containing acetoacetate groups (either before or after addition is fine). Methanol, ethanol, IsO-
Alcohols such as propanol and n-butanol, and cellosolves such as cellosolve and butyl cellosolve may be added as appropriate. Next, an explanation will be given according to an example.

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

When the temperature became constant, a mixture of 30y of styrene, 20q of methyl methacrylate, 30y of butyl acrylate, 20y of 2-hydroxyethyl methacrylate, and 1y of asobisisobutyronitrile as a polymerization initiator was added.
dripped over time. The polymerization rate reached almost 100% 5 hours after dropping. Viscosity Y (Gardner viscometer, 25℃
A colorless and transparent resin solution with a non-volatile content of 50% was obtained. Add this to the resin solution (1)
shall be. Next, 200 g of the resin solution (1) is placed in the reactor and heated to 50-60°C.

When the temperature becomes almost constant, 12.9q of diketene
, 0.05y1 of sodium acetate (anhydrous) and 12.9f of methyl ethyl ketone are added into the reactor. One minute after the addition, an infrared spectrum was measured and it was confirmed that the reaction had completed. At this point, a pale reddish brown transparent resin solution with a non-volatile content of 50% and a viscosity of x was obtained. This resin solution having an acetoacetate group is referred to as a resin solution (2). Next, add 5 y of a curing agent (referred to as curing agent (1)) obtained by mixing 340 y of tetra-n-butyl titanate and 200 y of acetylacetone to 100 y of this resin solution (2).
v added.

The obtained resin composition has a viscosity of Y-Z and a temperature of 50°C.
It remained very stable without showing any increase in viscosity during a 7-day storage stability test. Apply this composition on a glass plate (so that the film thickness after drying is 20-30μ)
Then, leave it in a constant temperature and humidity room at 25℃ and 65RH.
After that time, the gel fraction was measured.

The results are shown in Table 1. Note that 40q of rutile-type titanium oxide was blended with respect to 50q of non-volatile content of this composition, and the mixture was 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. Table 2 lists the properties of the resulting coating film. Example 2 100f of the resin solution (2) of Example 1, 284f of tetraisopropyl titanate, and 232 f of acetoacetic acid methyl ester
The resin composition obtained by adding 10 da of the curing agent obtained by mixing with q had a viscosity of Z and had excellent storage stability like the composition of Example 1.

As in Example 1, the gel fraction and performance with white enamel were investigated, and the results are listed in Tables 1 and 2, respectively. Example 3 First, 100 g of 2-hydroxyethyl acrylate was placed in the same reaction vessel as in Example 1 and heated to 60 to 70°C.

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 addition, it was confirmed by infrared nosvector that the reaction had completed. The monomer obtained by this reaction is called monomer (1). Next, put 50 g each of xylene and n-butyl acetate into the same reaction container as in Example 1, and
After heating to 0°C and when the temperature became constant at 7°C, styrene 20f1 methyl methacrylate 20g, methacrylic acid n
-Butyl 30y1 A mixed solution consisting of 30g of the above monomer (1) and 0.5y of lauryl peroxide as a polymerization initiator was dropped over 3 hours.

Six hours after dropping, the polymerization rate 9 reached almost 100%. A pale yellow transparent resin solution with a viscosity of N-2 and a non-volatile content of 50% was obtained. This is referred to as a resin solution (3). This resin solution (3)
100y, 1 fine body of tetra n-butyl titanate 5
y and 20 y of IsO-propyl alcohol were added to obtain a resin composition having a viscosity x and a nonvolatile content of 42%.

The gel fraction and white enamel performance of this composition were examined in the same manner as in Example 1, and the results are shown in Tables 1 and 2, respectively. Example 4 50 y each of xylene and n-butyl acetate were placed in the same reaction vessel as in Example 1, heated to 100°C, and when the temperature became constant, 20 g of styrene and 30 y of ethyl methacrylate were added.
A mixed solution consisting of 40q1 of butyl acrylate, 10 da of the above monomer (1), and 0.5q of tert-butyl peroxybenzoate as a polymerization initiator was dropped over a period of 3 hours.

The polymerization rate reached almost 100% 6 hours after dropping. Viscosity Z
A pale yellow transparent resin solution of -4 was obtained. This is referred to as a resin solution (4). To 100 q of this resin solution (4) was added 10 g of a curing agent obtained by mixing 970 y of tetramer of tetra-n-butyl titanate, 400 y of acetylacetone, and 930 y of diacetone alcohol. The resulting resin composition had a viscosity of Z-4. The gel fraction of this resin composition was measured in the same manner as in Example 1, and the various performances of the white enamel were also investigated. The results are listed in Tables 1 and 2.
For comparison, the following example is provided.

Comparative Example 1 5 y of the curing agent (1) of Example 1 was added to 100 q of the resin solution (1), which is a solution of the vinyl J polymer containing hydroxyl groups obtained in Example 1.

The obtained resin composition had a viscosity of Z-1 and a temperature of 50°C.
It was stable during the 7-day storage stability test without showing any increase in viscosity; however, when the gel fraction was measured in the same manner as in Example 1, it was 45%, which was 75% of that in Example 1.
It showed only a low value compared to . The test results for white enamel are shown in Table 2, and the solvent resistance was still inferior compared to the examples. Comparative Example 2 5 y of aluminum tree Sec butoxide and 20 y of IsO-propyl alcohol were added to 100 V of the resin solution (3) obtained in Example 3 to obtain a resin composition with a viscosity of Y1 and a non-volatile content of 42%.

The gel fraction and white enamel performance of this composition were examined in the same manner as in Example 1, and the results are shown in Tables 1 and 2, respectively. To increase the viscosity and lower the viscosity to the original viscosity Y,
1s0-propyl alcohol had to be added up to 15% non-volatile content. On the other hand, the resin composition obtained in Example 3 showed almost no increase in viscosity during a 7-day storage stability test at 50'C. Gel fraction of each comparative example, various performances with white enamel (all tested in the same way as Example 1)
are shown in Tables 1 and 2, respectively.

Claims (1)

[Claims] 1 General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (However, n is 0 or 1 to 10, R is carbon number 1 to 20
A titanium complex compound containing a compound capable of forming a titanate or a keto-enol tautomer (representing an alkyl group or an alkenyl group of 2 to 20) as a ligand forming a stable chelate ring has a curing action. A method for curing a vinyl polymer containing an acetoacetate group in the molecule, which is used as a component.