JPH0145501B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composition for forming a hydrolyzable resin film, and more particularly to a composition for forming a polyester resin film that can be gradually hydrolyzed and eluted under a specific environment. Polyester resin obtained by condensation polymerization of polybasic acid and polyhydric alcohol is dissolved in a solvent in the form of a relatively low molecular weight prepolymer.
It is widely used as a film-forming component in various paints because it forms a strong film by dry baking or by promoting crosslinking reaction with a catalyst. However, regardless of whether it is a prepolymer or a polymerized one, the ester bonds contained in polyester resins are extremely resistant to hydrolysis, etc., and do not undergo natural decomposition. This was considered to be one of the advantages of using polyester resin as a coating film forming component. However, in recent years, in the field of ship bottom paints, for example, if the relatively uneven paint surface is gradually hydrolyzed and dissolved by seawater during rowing and becomes a flat paint surface, it is possible to Frictional resistance will be felt, speed reduction will be prevented, and fuel efficiency will be greatly improved.
Additionally, hydrolyzable resins suddenly started to attract attention because it was thought that it would be difficult for marine organisms such as barnacles to attach to them. In order to be used as a coating composition, such a resin must be dissolved or at least dispersed in a solvent, and after coating the resin liquid, it must be possible to form a fairly stable coating film by evaporation of the solvent or simple post-treatment, and it must also be able to be decomposed. However, the decomposition rate must be controlled within a certain range depending on the intended use. Furthermore, the decomposition conditions must not be vastly different from the natural environment, and since various additives will naturally be added to make paint, it is difficult to use ordinary paint additives. It must be difficult to be influenced. When the present inventors make polyester by condensation polymerization of a polybasic acid and a polyhydric alcohol, the metal ester bond is used as the alcohol component or as a part thereof. [M is a metal element, l is an integer corresponding to the valence of the metal M] By using a polyhydric alcohol having the following, a large number of the metal ester bonds can be incorporated into the polyester main chain, and the polyester resin thus obtained is It is extremely stable against hydrolysis under neutral conditions, but under weakly alkaline or slightly acidic conditions it is gradually hydrolyzed and cleaved at the metal ester bonding site, releasing metal ions and releasing polar groups. They discovered that the compound was decomposed into a water-soluble segment having a carboxyl group, and filed a patent application entitled ``Process for producing hydrolyzable polyester resin'' on the same date as the present application. The present invention is a further development of the invention of the above patent application. That is, according to the present invention, a polybasic acid and at least a portion of the formula [In the formula, R is

[Formula] Or,

[Formula] R ₁ and R ₂ each represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; m and n each represent 0 or an integer of 1 to 16; R ₃ is represents an alkylene group having 1 to 8 carbon atoms;
M is group b of the periodic table (e.g. Cu, Ag), a
group (e.g. Mg, Ca, Ba), group b (e.g. Zn,
Cd, Hg), b group (e.g. Su, Pb), a group (e.g. Mn) or group (e.g. Fe, Co,
Ni) is a di- to tetravalent metal element; l represents an integer corresponding to the valence of the metal M] Consisting of a polyester resin consisting of a polyhydric alcohol which is a metal salt of a hydroxycarboxylic acid represented by the following and a solvent. A composition for forming a hydrolyzed resin film is provided. This polyester resin is prepared by combining a polybasic acid and a metal salt of hydroxycarboxylic acid of the above general formula (), or a polyhydric alcohol consisting of the metal salt of hydroxycarboxylic acid and a polyol, preferably in an inert solvent, with dibutyltin oxide. It can be advantageously produced by heating to a temperature below the decomposition point of the hydroxycarboxylic acid metal salt in the presence of a conventional polyester catalyst such as lithium naphthenate. As the polybasic acid, any difunctional or higher functional acid used in the production of normal polyesters can be used, such as oxalic acid, succinic acid, succinic anhydride,
Linear dibasic acids such as adipic acid, azelaic acid, and sebacic acid; phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride,
Aromatic fatty acids such as hexahydrophthalic acid, hexahydrophthalic anhydride, tetrabromophthalic anhydride, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride; maleic acid,
It can be an unsaturated polybasic acid such as maleic anhydride, fumaric acid, itaconic acid, etc. benzoic acid, if desired;
Basic acids such as pt-butylbenzoic acid and various animal and vegetable oils and fatty acids can also be used as molecular weight modifiers. The polyol used as the polyhydric alcohol may be any polyol used in the production of normal polyesters, such as ethylene glycol, propylene glycol, 1,3-butanediol,
1,6-hexanediol, diethylene glycol, neopentyl glycol, triethylene glycol, hydrogenated bisphenol A, bisphenol dihydroxypropyl ether, glycerin,
It can be trimethylolethane, trimethylolpropane, pentaerythritol, etc. However, the above-mentioned polyester resin contains at least one type of polyhydric alcohol component, or as a part thereof, the general formula () [In the formula, R, M and l are as described above] A metal salt of a hydroxycarboxylic acid represented by It is characterized by having a large number of metal-ester bonds. This polyester can be a prepolymer having a relatively low molecular weight, for example, a number average molecular weight of about 1,000 to 5,000, or a more polymerized version, which is inert and stable in water under a neutral atmosphere. However, under weak alkaline or acidic conditions, the above metals -
The resin component undergoes gradual hydrolysis at the ester bond site, releasing metal ions, and the resin component after hydrolysis acquires a polar carboxyl group, and is reduced in molecular weight and made soluble in water. Furthermore, it has been found that this hydrolysis rate varies depending on the type and amount of the hydroxycarboxylic acid metal salt in the polyester resin, the acid value and hydroxyl value of the polyester resin, and also varies depending on the selected metal species. . For example, when the equivalent weight of the hydroxycarboxylic acid metal salt in the resin is the same, as in Cu > Ni > Co > Zn > Mn > Mg > Ba > Ca, the more the metal-ester bond is It is easy to decompose, and the higher the amount of metal salt, the higher the hydrolysis point and the higher the rate of decomposition and elution of the resin.Solubility can also be improved by increasing the acid value and hydroxyl value of the resin. It has been confirmed that it can be made large. In addition to this knowledge, the present inventors have discovered that the above-mentioned resin is in the form of a prepolymer with a relatively low molecular weight, for example, a number average molecular weight of about 1000 to 5000, and is treated with ordinary organic solvents such as toluene, xylene, tetrahydrofuran, methyl isobutyl ketone, and butyl acetate. be soluble in vinyl monomers, styrene monomers, etc., and be compatible with various resin liquids, and be cured by removing the solvent from the solution, by heat treatment, or by curing using a catalyst as in the case of two-component paints. It was also discovered that the above resins are not affected by additives or chemicals added for coating or other purposes as long as they are coated with prepolymer or polymerized polyester and maintained under neutral conditions. The present invention was completed based on the finding that a composition consisting of a compound containing a polyester compound and a solvent is extremely suitable as a type of resin film forming agent that is hydrolyzed under specific conditions. In the present invention, it is particularly preferable that the polyester resin is dissolved in the solvent in the form of a prepolymer, but it is also preferable that the polyester resin is a polymeric resin that is not dissolved but simply maintained in a dispersed state in the solvent. For example, if it is used in combination with other resin vehicles or if other resin vehicles are used as a solvent, it can be used to form a sufficient film, and the film obtained in this way also gradually loses its polyester portion under weakly alkaline or slightly acidic conditions. It is hydrolyzed and eluted. Therefore, the polyester resin of the present invention is not limited to a prepolymer, but may have any degree of condensation. Regarding solvents, solvents for dissolving the prepolymer, such as aromatic solvents such as toluene and xylene; ketones such as methyl ethyl ketone and methyl isobutyl ketone; esters such as cellosolve acetate and butyl acetate; alcohols such as butyl alcohol; Although ethers such as 4-dioxane and tetrahydrofuran are particularly preferred, they may be prepolymers or dispersion compositions of polymers, so even solvents with poor solubility may be used, and as mentioned above, alkyds and other In some cases, it may be a resin liquid, or it may be an unsaturated monomer such as styrene monomer or vinyl monomer that can be mixed with unsaturated polyester. Therefore, the term "solvent" in this specification should be understood as a synonym for a diluent for the polyester resin that does not normally react with the polyester resin of the present invention. The composition of the present invention is expected to have a wide range of uses, particularly in the field of paints, as a resin film forming agent that is gradually hydrolyzed under certain conditions. This is clear from the fact that when using ordinary paints, people were only concerned about their weather resistance and did not think about how to remove old paints. In other words, the paint containing the composition of the present invention as a vehicle can not only be used for ordinary painting purposes, but also can be removed by hydrolytic means under alkaline or acidic conditions without using large amounts of expensive solvents. This is because the combination enables more effective cleaning. Furthermore, the composition of the present invention exhibits a unique effect when applied as a varnish, particularly to underwater structures, fixed nets, ships, etc. As mentioned above, the composition of the present invention forms a stable coating film that is inert to water in a neutral atmosphere. However, seawater provides suitable alkaline conditions for hydrolysis of coatings made with the compositions of the present invention. Therefore, the coating film undergoes gradual hydrolysis and elution in the sea, and at the same time releases metal ions. The coating surface is relatively uneven during painting, but when applied to the bottom of a ship, for example, the more the ship runs, the more the convex parts of the coating collide with water molecules, selectively hydrolyzing and dissociating and eluting. This creates a smooth surface, which reduces frictional resistance and improves fuel efficiency. Furthermore, if the metal in the polyester resin is selected to be capable of releasing relatively toxic metal ions such as Cu, Pb, and Sn, it can prevent marine organisms from adhering to underwater structures, and prevent clogging of fixed nets. Also useful. Another important field of use is agricultural use. For example, if a pesticide capsule is made from the composition of the present invention, and a fast-acting aqueous solution of various pesticides is sealed and applied to a soil, the resin will be gradually hydrolyzed in the acidic or alkaline soil, so the thickness of the capsule coating and the resin composition By selecting , it is possible to maintain the effects of fast-acting pesticides over a long period of time. Furthermore, the kindan seeds in the polyester resin are added to substances necessary for plant growth such as Mg, Mn, Zn, etc.
By selecting trace elements such as Cu, Mo, Fe, etc., the metal ions themselves released during hydrolysis can be used. As described above, since the composition of the present invention is used as a hydrolyzable resin film-forming agent, it is expected to find wide application in coatings, agricultural chemicals, and other fields that were previously unanticipated. The present invention will be explained below with reference to Examples. Example 1 100 parts of copper 12-hydroxystearate (parts by weight, the same applies hereinafter), 245.5 parts of phthalic anhydride, and 25 parts of toluene were added to a three-necked flask equipped with a refluxer, dropping funnel, and stirrer and heated to 100°C. . Then 1,6-
Add 191 parts of hexanediol and 1 part of dibutyltin oxide (catalyst) and heat to 160°C under _N2 gas atmosphere.
The condensation reaction was continued for 8 hours while the water produced was removed from the system. As the dehydration progressed, the temperature of the system increased, and the reaction was conducted at a final temperature of 180°C. Then cool to 110℃ and methyl isobutyl ketone 263
A deep green varnish with a solid content of 62.7%, a Gardner viscosity G, and a solid content residual value of 9.7 was obtained.
This varnish is called A. The acid value was measured by titration with a 0.5N KOH/methanol solution using methyl red as an indicator. Example 2 100 parts of copper 12-hydroxystearate, 41 parts of phthalic anhydride, 10 parts of xylene, and 0.2 parts of dibutyltin oxide were heated to 160°C under _N2 gas and reacted in the same manner as in Example 1 while dehydrating. Ta. It was diluted with 50 parts of tetrahydrofuran to obtain a deep green varnish (B) having a solid content of 68.8%, a Gardner viscosity P, and a solid content acid value of 9.5. Example 3 In the same manner as in Example 1, 101 parts of zinc 12-hydroxystearate, 246 parts of phthalic anhydride, 166.4 parts of neopentyl glycol, 25 parts of toluene, 1 part of dibutyltin oxide, and methyl isobutyl ketone as a diluent were added. Using 236 parts, a clear varnish (C) having a solid content of 65.4%, a Gardner viscosity of J, and a solid content acid value of 9.6 was obtained. Example 4 In the same manner as in Example 1, 38 parts of copper lactate, 245.5 parts of phthalic anhydride, 215 parts of dipropylene glycol,
Using 25 parts of toluene, 1 part of dibutyltin oxide, and 189 parts of methyl isobutyl ketone, solid content 69.8%,
A deep green varnish (D) with a Gardner viscosity of N and a solid acid value of 9.9 was obtained. Example 5 In the same manner as in Example 1, 46 parts of zinc lactate, 148 parts of phthalic anhydride, 95 parts of adipic acid, 36 parts of trimethylolethane, 128 parts of 1,3-butanediol, 25 parts of toluene, 1 part of dibutyltin oxide parts, using 205 parts of methyl isobutyl ketone as diluent,
Solid content 65.3%, Gardner viscosity V, solid content acid value
Obtained 10.0 clear varnish (E). Example 6 In the same manner as in Example 1, 253 parts of phthalic anhydride,
Using 24 parts of copper lactate, 50.4 parts of pentaerythritol, 105.4 parts of neopentyl glycol, 1 part of dibutyltin oxide, and 370 parts of methyl isobutyl ketone,
Solid content 50.3%, Gardner viscosity T, solid acid value
A dark green varnish (F) of 9.6 was obtained. Example 7 In the same manner as in Example 1, hexahydrophthalic acid
Using 263.3 parts, 28 parts of magnesium nitrate, 4.5 parts of sodium lactate, 50.4 parts of pentaerythritol, 105.4 parts of neopentyl glycol, 1 part of dibutyltin oxide, and 200 parts of methyl isobutyl ketone,
Solid content 65.3%, Gardner viscosity S, solid acid value
9.7 transparent varnish (G) was obtained. Example 8 In the same manner as in Example 1, 253 parts of phthalic anhydride,
Magnesium salt of mono(w-hydroxyhexyl) phthalate 83 parts, pentaerythritol 50.4 parts
Using 105.4 parts of neopentyl glycol, 1 part of dibutyltin oxide, and 345 parts of methyl isobutyl ketone as a diluent, a transparent varnish (g) having a solid content of 55.4%, a Gardner viscosity U, and a solid content acid value of 9.4 was obtained. Example 9 The same method as Example 8 was used except that 90 parts of zinc salt of mono(w-hydroxyhexyl) phthalate was used instead of 83 parts of magnesium salt of mono(w-hydroxyhexyl) phthalate, solid content 54.8%, Gardner viscosity U, solid content acid value 9.6 transparent varnish (I)
I got it. Example 10 An n-butanol-modified melamine resin having a number average molecular weight of 1100 and having 2.2 alkoxylated atoms per triazine skeleton and varnish A of Example 1 were mixed at a solid content ratio of 3/7, and varnish (J) was mixed. Obtained. Example 11 Example 7 except that 10.2 parts of iron 12-hydroxystearate and 45.1 parts of pentaerythritol were used instead of 50.4 parts of pentaerythritol in Example 7.
A transparent varnish (K) having a solid content of 68.2%, a Gardner viscosity Q, and an acid value of solid content of 9.2 was obtained in the same manner as above. The degree of hydrolysis of this varnish was measured by the method described in the text. As a result, a value of degree of hydrolysis = 0.23 was obtained. Example 12 Titanium 12-hydroxystearate was used instead of 50.4 parts of pentaerythritol in Example 7.
A transparent varnish (L) with a solid content of 64.4%, a Gardner viscosity U, and an acid value of solid content of 9.6 was prepared in the same manner as in Example 7 except that 7.7 parts and 45.1 parts of pentaerythritol were used.
I got it. The degree of hydrolysis of this varnish was measured by the method described in the text. As a result, a value of degree of hydrolysis = 0.21 was obtained. The following varnishes were made for comparison purposes. Comparison varnish 1 58.1 parts of phthalic anhydride, neopentyl glycol
According to the method of Example 1, a varnish having a solid content of 50.4%, a Gardner viscosity P, and a solid content acid value of 9.7 was prepared from 12.1 parts of 1,6-hexanediol, 9.6 parts, and 20.5 parts of trimethylolethane. Comparative Varnish 2 The solid content was adjusted according to the method of Example 1 using 54.9 parts of phthalic anhydride and 50.1 parts of 1,6-hexanediol.
A varnish with a Gardner viscosity of 65.3%, a Gardner viscosity of J, and a solid content acid value of 9.7 was prepared. Comparative varnish: An initiator solution containing 50 parts of methyl methacrylate, 50 parts of tributyltin methacrylate, and 0.8 parts of benzoyl peroxide in 100 parts of toluene was prepared at 90°C for 30 minutes.
The mixture was added dropwise over a period of time to produce a varnish with a solid content of 50.4% and a Gardner viscosity of N. Although this product is not polyester-based, it is an acrylic resin that is known to gradually hydrolyze the coating film, so it was made for comparison purposes. The following experiment was conducted to demonstrate the fact that a film made from the polyester resin composition of the present invention is gradually hydrolyzed and eluted under alkaline conditions. Each varnish was applied to a glass plate measuring 60 mm long x 50 mm wide so that the dry film thickness was 100μ, heated at 105°C for 3 hours (however, varnish J was baked at 140°C for 30 minutes), and the initial weight was Weigh accurately. Next, this glass plate is immersed in 350 c.c. of an alkaline aqueous solution with a pH of 10, held at 40°C for 18 hours, and then taken out, washed with water, dried, and the final weight is precisely weighed. From these weight differences, determine the degree of hydrolysis using the formula below. Degree of hydrolysis = initial weight - final weight / initial weight The test results are as shown in Table 1. Table 1 Varnish hydrolysis degree A 0.32 B 0.30 C 0.28 D 0.30 E 0.25 F 0.24 G 0.20 H 0.22 I 0.23 J 0.12 Comparison 1 0.00 Comparison 2 0.00 Comparison 3 0.16

Claims (1)

[Claims] 1. A polybasic acid and at least a portion of the formula: [In the formula, R is a group represented by [Formula] or [Formula]; R ₁ and R ₂ each represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; m and n each represent 0 or represents an integer of 1 to 16; R ₃ represents an alkylene group having 1 to 8 carbon atoms;
M is a di- to tetravalent metal element belonging to b, a, b, b, a or group of the periodic table;
1 represents an integer corresponding to the valence of metal M] A composition for forming a hydrolyzed resin film comprising a polyester resin comprising a polyhydric alcohol which is a metal salt of a hydroxycarboxylic acid represented by the following and a solvent. 2 M is Cu, Ag, Mg, Ca, Ba, Zn, Cd,
The composition according to claim 1, which is selected from the group consisting of Hg, Sn, Pb, Mn, Fe, Co and Ni.