JPS6050225B2 - Method of curing 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, the present invention relates to a method for curing a vinyl polymer containing an acetoacetate group in the molecule, and more specifically, the present invention relates to a method for curing a vinyl polymer containing an acetoacetate group in the molecule, and more specifically, the general formula OR-OR, . Zirconates or A zirconium complex compound containing a compound capable of forming a keto-enol tautomer as a ligand forming a stable chelate ring is used as a curing component, and contains an acetoacetate group in the molecule. The present invention relates to a method of curing vinyl polymers.

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 is combined with another monomer having a polymerizable unsaturated group. It can also be obtained by polymerizing
Ru.

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 with a vinyl polymer having a hydroxyl group in the molecule to produce a cured product having a Ξ-dimensional structure, thereby further widening its uses. The method involves adding urea resin to a vinyl polymer that has hydroxyl groups in the molecule.
Thermosetting resin compositions are made by blending amino resins such as melamine resins, but these require heating at a relatively high temperature, usually 80 to 2000C, for about 10 to 30 minutes during curing. This goes against 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, it is generally a two-part type. Because the curing agent component is added immediately before use, there are problems with storage stability after the curing agent is added, and combined with the toxicity of the isocyanate compound, it is extremely inconvenient to handle. many. As a method of providing a cured product with excellent transparency, ultraviolet resistance, and chemical resistance without using amino resins such as urea resins and melamine resins or isocyanate compounds as described above, epoxy groups and/or hydroxyl groups are added in 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 hydroxyl group at the β position is added to the acrylic polymer having a group as a curing agent component. A curing method in which the compound is compounded as follows is known.

(Japanese Patent Publication No. 45-9073) However, even in this curing method, it is generally
Powder heat treatment is required, and even if the coating cures at room temperature, if the cured coating is immersed in an organic solvent such as alcohol or cellosolve, many parts will dissolve in the solvent. There is.

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

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. Ken!
As a result of research, it was found that a vinyl polymer having an acetoacetate group in the molecule has a curing component of the general formula (where n is 0 or 1 to 5, and R is an alkyl group having 1 to 20 carbon atoms or an alkyl group having 2 to 20 carbon atoms). A curing method characterized by using a zirconium complex compound containing a zirconate represented by an alkenyl group or a compound capable of forming a ketoenol tautomer as a ligand forming a stable chelate ring. Heading The invention has been completed.

Consists of zirconates or keto enol tautomers represented by the general formula (where n is O or 1 to 5, R is an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms) A curing agent for alkyd resins, epoxy resins, phenolic resins, and vinyl polymers containing hydroxyl groups and/or hydroxyl groups in the molecule. However, as in the present invention, when these are used as curing agents for vinyl polymers containing acetoacetate groups in the molecule, transparency, ultraviolet resistance, chemical resistance, solvent resistance, A method for obtaining a coating film with excellent physical properties is not yet known.

The details of the mechanism of the curing method of the present invention are unknown, but by drying or volatilizing the solvent, a vinyl polymer containing an acetoacetate group and an aluminum alcoholate or a compound capable of keto-enol tautomerization are bonded to a ligand. It is thought that a ligand exchange reaction occurs with the aluminum complex compound contained as a compound, resulting in crosslinking, resulting in hardening. In the vinyl polymer containing an acetoacetate group, a hydroxyl group or a carboxyl group may be contained in addition to the acetoacetate group. (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 combination of a vinyl polymer having a hydroxyl group and a diketene. can be obtained by reacting them in the presence of an acid-base catalyst.

Diketene is Mp-6.5℃, BPI27.4℃, n?
01.4379, d? 81.0897, vapor pressure (200
C) 8.0nn1, colorless, lachrymatory liquid with strong pungent odor.

(A.B.Boesellnd..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 can be carried out using an organic solvent that does not have an active hydrogen group, such as ketones, esters, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents,
By dissolving a vinyl polymer having hydroxyl groups in these mixed solvents, adding the above acid-base catalyst to the solvent, adding diketene with stirring, and keeping warm at room temperature to 70'C for 1 to 1 hour. can get. The amount of the acid-base catalyst added is 0 per 10 parts by weight of the vinyl polymer having hydroxyl groups.
．． 01 to 10 parts by weight, preferably 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, in the vinyl polymer, the acetoacetate group is
It is necessary that the content be 5 mol% or more.

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 methacrylate (-CH3 general formula is CH2-C- C-
0(CH2CH2O)NHn: 5-1), polypropylene glycol monomethacrylate (general formula is CH2=y?-0(CH2×heat:)NHlOn=5
~6) etc. can be used.

Further, 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, vinyltoluene, N- Vinylpyrrolidone, acrylic esters, methacrylic esters, itaconic esters, maleic esters, fumaric esters, crotonic esters, acrylonitrile, methacrylonitrile, and the like are included.

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 a vinyl polymer having a hydroxyl group with diketene. 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. You can also 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. Obtained by reacting with diketene in the presence of an acid base and a 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 five ester groups and a ketocarbonyl group of this acetoacetate group appear at 1750 cm-1 and 1710 cm-1, respectively. This 1710 cm-1 overlaps with the absorption of acrylic esters and methacrylic esters, but 1750C77! −
The absorption of 1 is clearly discernible.

Although the absorption is weak, the absorption of 91610c7ri-1 appears due to the formation of CC double bonds in the enol form. This is one of acrylic ester and methacrylic ester.
It is observed that an absorption shoulder of 630 to 1640 cTn-1 appears. Therefore, the end point of the reaction between hydroxyl group and diketene is 1750c7n-1 in the infrared spectrum.
It was considered that the change in the absorption of 1610c7n-1 and the change in the absorption of 1610c7n-1 disappeared and reached a maximum. (The completion of the reaction was confirmed by infrared spectra in the Examples based on the above-mentioned idea and method.) Next, the general formula (where n is O or 1 to 5, R is 1 carbon number) Regarding a zirconium complex compound containing a compound capable of forming a zirconate or a keto-enol tautomer represented by ~20 alkyl groups or 2 to 20 alkenyl groups as a ligand forming a stable chelate ring. state

Zirconates represented by the above general formula include tetraethyl zirconate (n=3 to 4 in the above general formula),
Tetra JsO-propyl zirconate (n = 3), tetra n-propyl zirconate (n x 3), tetra n-butyl zirconate (n = 3 to 4), tetra Tert-butyl zirconate (n = 1), Tetra Sec-butyl zirconate (n = 1), tetra n-pentyl zirconate (n = 3 to 4), tetra Tert-pentyl zirconate (n = 1), tetra Tert-hexyl zirconate (n = 1), Tetra n-heptylzirconate (n
= 3), tetra n-octyl zirconate (n = 3-4
), tetra n-stearyl zirconate, etc., especially tetra JsO-propyl zirconate, tetra n-
Suitable results are obtained using butyl zirconate and the like.
Compounds that can constitute keto-enol tautomers include β-diketones (acetylaceton, etc.), acetoacetic esters (methyl acetoacetate, etc.), malonic esters (ethyl malonate, etc.), and 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 with hydroxyl/group in position (methyl salicylate, etc.)
can be used. In particular, suitable results can be obtained by using acetoacetic acid esters and β-diketones. Any zirconium complex compound that can be used as a curing component can be prepared by mixing a compound capable of forming the above-mentioned keto enol tautomer in a molar ratio of 4 moles or less to the Zrl mole in the above-mentioned zirconate. It can be prepared as follows. As already mentioned, in the curing method of the present invention, a vinyl polymer containing an acetoacetate group is added to a vinyl polymer having a general formula (where n is 0 or 1 to 5, and R is an alkyl group having 1 to 20 carbon atoms or 2 A zirconium complex compound containing a zirconate represented by ~20 alkenyl groups or a compound capable of forming a keto-enol tautomer as a ligand forming a stable chelate ring is used as a curing component. It is carried out by doing. A curing component for a vinyl polymer containing an acetoacetate group, that is, a general formula (where n is O or 1 to 5, and R represents an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms) The amount of the zirconium complex compound containing a compound capable of forming a zirconate or ketoenol tautomer represented by as a ligand forming a stable chelate ring is determined by the concentration of acetoacetate groups in the vinyl polymer, zirconate or zirconium complex compound, so they cannot be specified uniformly, but generally the resin solid content of the vinyl polymer is 1 (4
) 0.1 to 5 parts by weight, preferably 1 to 2 parts by weight, of zirconates and zirconium complex compounds are blended with respect to parts by weight.

To check the degree of hardening, zirconates and zirconium complex compounds were added to a vinyl polymer containing an acetoacetate group, and after coating on a glass plate, the mixture was heated at 25°C and 65°C.
%RH in a room with constant temperature and humidity, and after a certain period of time, part of the coating (approximately 1 g) was peeled off and divided into strips of 200.
Wrap it in a mesh stainless steel wire gauze and immerse it in boiling acetone/IsO-propyl alcohol at a weight ratio of 1/1 for 8 hours* to extract the acetone-soluble portion and dry the extracted residue at 105°C for 3 hours. The gel fraction was measured by the following method.

When the gel fraction of the coating film cured by the present curing method was measured, the calculation formula showed a gel fraction of 50 to 100%, indicating that curing had been completed.

In addition, zirconates and zirconium complex compounds have properties that include aluminum complex compounds that contain compounds that can form aluminum alcoholates or keto-enol tautomers as a ligand to form a stable chelate ring, and general aluminum complex compounds. Formula (where n is 0 or 1 to 10.R is carbon number 1 to 20
It is similar to a titanium complex compound containing a compound capable of forming a titanate or a ketoenol tautomer represented by an alkyl group or an alkenyl group of 2 to 20 as a ligand forming a stable chelate ring. However, zirconate and zirconium complex compounds have better storage stability than aluminum alcoholates and aluminum complex compounds.

Furthermore, when titanates and titanium complex compounds are used as curing components of vinyl polymers containing acetoacetate groups, yellowing of the coating may be observed, but in the case of zirconates and zirconium complex compounds, It is characterized by almost no yellowing. In addition, in order to further improve storage stability, methanol was added to a system in which zirconates and zirconium complex compounds were added to a vinyl polymer containing an acetoacetate group (either before or after the addition). , alcohols such as ethanol, IsO-propanol, and n-butanol, and cellosolves such as cellosolve and butyl cellosolve may be added as appropriate.

Examples will be explained below.

Example 1 500m equipped with thermometer, stirrer, cooler and drip load
50 y of toluene and n-butyl acetate were each placed in a four-round flask, and after the air was replaced with nitrogen gas, the flask was heated to 100°C.

When the temperature became constant, a mixture of 30y of styrene, 20y of methyl methacrylate, 30V of butyl acrylate, 20V of 2-hydroxyethyl methacrylate, and 1y of azobisisobutyronitrile 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
) Next, add 200y of resin solution (1) to the above reactor.
and heat to 50-60°C.

When the temperature became almost constant, 12.9y of diketene
Add 12.9 f of sodium 1 acetate (anhydrous) 0.05y1 methyl ethyl ketone into the reactor. 1 C@ 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 nonvolatile content of 50% and a viscosity of x was obtained. (This resin solution with acetoacetate group is converted into resin solution (2).
shall be. )) Next, a curing agent (curing agent (1)) obtained by mixing 953f of tetra n-butyl zirconate (3.4 mer) and 1020f of acetylacetone with 100 g of this resin solution (2) is used.

Colorless crystalline powder. ) was added for 5y. The resulting resin composition had a viscosity of Y, and was extremely stable without showing any increase in viscosity during a 7-day storage stability test at a temperature of 50'C. This composition was coated on a glass plate (so that the film thickness after drying was 20 to 30 μm) and left in a constant temperature and humidity room at 25°C and 65RH, and the gel fraction was measured after 2 hours. .

The results are shown in Table 1. In addition, the nonvolatile content of this composition is 50f.
40V rutile type titanium oxide was blended with the mixture and kneaded with a three-roll roll to obtain white enamel.

This white enamel was diluted to an appropriate viscosity, sprayed onto a phosphate-treated steel plate, and dried for two hours at room temperature (20°C). Table 2 lists the performance of the resulting coating film. Example 2 A resin composition obtained by adding 10y of a curing agent obtained by mixing 100V of the resin solution (1) of Example 1, 745y of tetraisopropyl zirconate (trimer), and 700y of methyl acetoacetate was The viscosity is z, and Example 1
It had excellent storage stability like the composition of .

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 3 100 y of 2-hydroxyethyl acrylate is placed in a reaction vessel similar to that in Example 1, and heated to 60 to 70C.

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 by infrared spectrum that the reaction was complete. The monomer obtained by this reaction is called monomer (1). Next, 50 y each of xylene and n-butyl acetate were placed in the same reaction container as in Example 1, and 100 y.
After heating to ℃ and when the temperature becomes constant, styrene 20
A mixed solution consisting of y1 methyl methacrylate 20y1 n-butyl methacrylate 30y, 30y of the above monomer (1), and 0.5y lauryl peroxide as a polymerization initiator was added dropwise 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 called resin solution (3).) This resin solution (
3) Tetra n-butyl zirconate (3) to 100 g
．． tetramer) 5J (51S0-propyl alcohol 20y
was added to obtain a resin composition having a viscosity of W-X1 and a non-volatile content of 41%.

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 reached a constant 4, 20 y of styrene and 30 y of ethyl methacrylate were added.
y1 Butyl acrylate 40 y1 Above monomer (1) 10
A mixed solution consisting of Y and 0.5 da of tert-butyl peroxybenzoate as a polymerization initiator was added dropwise over 3 hours.

The polymerization rate reached almost 100% 6 hours after dropping. Viscosity Z-
A pale yellow transparent resin solution of No. 4 was obtained. (This is referred to as a resin solution (4).) To 100 y of this resin solution (4), add 9531 y of tetra n-butyl zirconate (3.4 mer), 340 y of acetylacetone, 442 y of ethyl acetoacetate.
10q of a curing agent obtained by mixing the above were added.

The resulting resin composition had a viscosity of Z-3. The gel fraction of this resin composition was measured in the same manner as in Example 1,
Furthermore, Table 1 shows the results of investigating various performances of white enamel.
Listed in 2. For comparison, the following example is given.

Comparative Example 1 The curing agent of Example 1 (
5g of 1) was added.

The obtained resin composition had a viscosity of Z-1 and was stable without showing any increase in viscosity during a 7-day storage stability test at a temperature of 50°C. The gel fraction was measured and was 40%, which was 72% 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 To 100f of the resin solution (3) obtained in Example 3, 5fI of aluminum tree Sec-butoxide was added. By adding 20q of ISO-propyl alcohol, the viscosity is Y and the non-volatile content is 4.
A 2% resin composition was obtained.

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. In order to increase the viscosity and lower the viscosity to the original viscosity Y, it was necessary to add 1s0-propyl alcohol to a non-volatile content of 15%. On the other hand, the resin composition obtained in Example 3 showed almost no increase in viscosity during the 7-day storage stability test at 50°C. Comparative Example 3 To 100 y of the resin solution (2) obtained in Example, 5 f of a curing agent obtained by mixing 284 y of tetra-IsO-propyl titanate and 200 y of acetylacetone was added.

The obtained resin composition had a viscosity of Y and was very stable without showing any increase in viscosity during a 7-day storage stability test at a temperature of 50°C. When painted and dried, the color of the paint film becomes yellowish. On the other hand, when the composition obtained in Example 1 was made into a white enamel, painted, and dried, no coloration of the coating film was observed.

The gel fraction and various performances of white enamel in each comparative example (all tested in the same manner as in 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 5, R represents an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms) A zirconium complex compound containing a compound capable of forming a zirconate or a keto-enol tautomer represented by as a ligand forming a stable chelate ring is used as a curing component. A method for curing vinyl polymers containing acetate groups.