JP2006206852A - Method for crosslinking water-based resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for crosslinking a water-based resin, by which a hydroxy group-containing water-based resin is stably preserved in a mixed state with a crosslinking agent and a crosslinking temperature is arbitrarily set. <P>SOLUTION: The crosslinking method comprises contacting and mixing a titanium alkoxide with one or more components selected from a hydroxycarboxylic acid, an aliphatic amine and a glycol. Consequently, the crosslinking reaction of a water-based resin containing a hydroxy group starts at 80-200°C in the presence of a water-based titanium composition and the insolubilization ratio of the resin is increased by ≥50% at a temperature difference within 50°C. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for crosslinking an aqueous resin with an aqueous titanium composition, and particularly to a method for suppressing crosslinking of an aqueous resin at low temperatures and crosslinking at higher temperatures. By using this, it can be used as a crosslinking agent for water-based resins in paints, inks, adhesives, barrier coating agents and the like.

Titanium alkoxide reacts with a compound having a hydroxyl group, a carboxyl group or the like in the molecule as a crosslinking agent, and is therefore used as an adhesion improving agent, a coating crosslinking agent, a coating heat resistance improving agent, and the like. Further, it is widely used industrially as a catalyst for titanium oxide thin film production and esterification by the sol-gel method. However, since titanium alkoxide has very high hydrolyzability, insoluble matter is likely to be generated during operation and storage even by moisture in the air. Moreover, when using titanium alkoxide, it is necessary to use a large amount of an organic solvent, and the environmental load becomes extremely high. For this reason, a water-soluble or water-based titanium composition has been studied as a titanium component having low environmental load and resistance to hydrolysis. The water-soluble or water-based titanium compound technology currently on the market is a method in which a chelating agent is reacted with titanium alkoxide, and titanium lactate or alkanolamine obtained by reacting lactic acid, which is a hydroxycarboxylic acid, with titanium alkoxide. There are titanium triethanolaminate obtained by reacting triethanolamine and titanium alkoxide, and titanium oxalate obtained by reacting oxalic acid that is dicarboxylic acid and titanium alkoxide. This is described in, for example, (Patent Document 1) and (Non-Patent Document 1). However, titanium lactate obtained by reacting lactic acid, which is a hydroxycarboxylic acid, and titanium alkoxide, tends to cause white precipitation during storage. In addition, titanium triethanolaminate obtained by reacting alkanolamine triethanolamine and titanium alkoxide initially forms an aqueous solution. However, when mixed at 1 to 1 with water and stored at 40 ° C., it becomes turbid after one month. The fluidity is lost and a brown gel state is obtained. (Patent Document 2) describes a method for producing a titanium-containing aqueous solution using an aliphatic amine, but it takes a long time to make the aqueous solution, and when a small amount of water is added, the composition becomes a white solid. It is impossible to obtain a uniform and transparent liquid. Furthermore, when titanium lactate is mixed with a water-based resin having a hydroxyl group, it is liquid at room temperature immediately after mixing, but when stored at 40 ° C. or stored at room temperature for a long time, it becomes a gel state and the workability is very poor. Similarly, when titanium triethanolamate was mixed, there was a problem that it immediately became a gel state.

JP 53-98393 A JP 2001-322815 A Sugiyama Iwayoshi, “Contained Metal Organic Compounds and Their Use”, M.M. R. Functional substance series No. 5, Japan, CMI Co., Ltd., March 18, 1983, p. 73-74

  In the present invention, the crosslinking reaction of a water-based resin having a hydroxyl group in the coexistence of a water-based titanium composition starts at 80 ° C. to 200 ° C., and the insolubilization rate defined in Example 1 is increased by 50% or more at a temperature difference within 50 ° C. An object of the present invention is to provide a method for crosslinking a water-based resin having a hydroxyl group, characterized in that In the conventional crosslinking method using an aqueous titanium compound, since a crosslinking reaction occurs even at a low temperature, it cannot be stably stored in a state where a crosslinking agent is mixed with an aqueous resin, and the crosslinking temperature is arbitrarily set. There was a problem that could not be done. An object of the present invention is to provide a method for crosslinking an aqueous resin that can be stably stored in a state in which a crosslinking agent is mixed with an aqueous resin having a hydroxyl group, and further, the crosslinking temperature can be arbitrarily set.

  The present inventors have intensively studied a method that can be stably stored for a long time in a state where an aqueous titanium composition is mixed with an aqueous resin having a hydroxyl group. As a result, when a titanium alkoxide, an oxycarboxylic acid, and one or more components selected from aliphatic amines and glycols are contacted and mixed, the crosslinking reaction of the aqueous resin having a hydroxyl group in the presence of the aqueous titanium composition is 80. The inventors have found a crosslinking method that can start at a temperature of from 200 ° C. to 200 ° C. and increase the insolubilization rate by 50% or more at a temperature difference within 50 ° C.

（式中、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４はそれぞれ水素、アルキル基、ヒドロキシアルキル基のいずれかである）で表されるグリコール（Ｄ）から選ばれる１以上の成分を接触してなり、チタンアルコキシドに対しオキシカルボン酸のモル比が０．１以上である組成物の共存下で、水酸基を有する水系樹脂の架橋反応が８０℃〜２００℃で始まり、８０℃以下における当該樹脂の不溶化率が４０％以下であり、５０℃以内の温度差において、不溶化率を５０％以上増加させることを特徴とする水系樹脂の架橋方法である。That is, the present invention relates to titanium alkoxide (A), oxycarboxylic acid (B), aliphatic amine (C), and general formula (I).

(Wherein R ₁ , R ₂ , R ₃ , and R ₄ are each hydrogen, an alkyl group, or a hydroxyalkyl group) one or more components selected from glycol (D) represented by In the presence of a composition having a molar ratio of oxycarboxylic acid to titanium alkoxide of 0.1 or more, the crosslinking reaction of the aqueous resin having a hydroxyl group starts at 80 ° C. to 200 ° C. A water-based resin crosslinking method characterized in that the insolubilization rate is 40% or less and the insolubilization rate is increased by 50% or more at a temperature difference within 50 ° C.

  Furthermore, the present invention is a method for crosslinking an aqueous resin, characterized in that the crosslinking agent according to claim 1 is added after the oxycarboxylic acid (B) is blended with the aqueous resin.

（式中、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４はそれぞれ水素、アルキル基、ヒドロキシアルキル基のいずれかである）で表されるグリコール（Ｄ）から選ばれる１以上の成分を接触してなり、チタンアルコキシドに対しオキシカルボン酸のモル比が０．１以上である組成物が水溶液である請求項１および２の水系樹脂の架橋方法である。Furthermore, the present invention comprises titanium alkoxide (A) and oxycarboxylic acid (B) as essential components, and further comprises oxycarboxylic acid (B), aliphatic amine (C), and general formula (I).

(Wherein R ₁ , R ₂ , R ₃ , and R ₄ are each hydrogen, an alkyl group, or a hydroxyalkyl group) one or more components selected from glycol (D) represented by The method according to claim 1 or 2, wherein the composition having a molar ratio of oxycarboxylic acid to titanium alkoxide of 0.1 or more is an aqueous solution.

  Furthermore, the present invention is the method for crosslinking an aqueous resin according to claims 1, 2 and 3, wherein the aqueous resin is polyvinyl alcohol or a resin containing a vinyl alcohol unit.

  In the present invention, the crosslinking reaction of the aqueous resin having a hydroxyl group in the coexistence of the aqueous titanium composition starts at 80 ° C. to 200 ° C., the insolubilization rate of the resin at 80 ° C. or lower is 40% or lower, and the temperature is within 50 ° C. In the difference, the present invention provides a method for crosslinking a water-based resin having a hydroxyl group, wherein the insolubilization rate is increased by 50% or more. The crosslinking method of the aqueous resin having a hydroxyl group in the presence of this aqueous titanium composition can suppress the crosslinking reaction at 80 ° C. or lower compared to the conventional crosslinking method using an aqueous titanium compound. It can be stably stored in a state where a crosslinking agent is mixed. Furthermore, if a combination of titanium alkoxide (A), oxycarboxylic acid (B), aliphatic amine (C), and glycol (D) is selected. The crosslinking temperature of the aqueous resin having a hydroxyl group can be arbitrarily set. In addition, it is possible to rapidly cause crosslinking of the aqueous resin at a temperature difference of 50 ° C. or less, and it is possible to cause a crosslinking reaction triggered by temperature. Therefore, it is possible to express two types of reactions stepwise by changing the temperature in the same system.

  The present invention is described in further detail below. The aqueous titanium composition of the present invention comprises the following titanium alkoxide (A) and oxycarboxylic acid (B) as essential components, and is further selected from oxycarboxylic acid (B), aliphatic amine (C) and glycol (D). It consists of one or more components.

The titanium alkoxide (A) is represented by the following general formula (II).

R ₅ , R ₆ , R ₇ and R ₈ each represents an alkyl group and may be the same or different. Carbon number of a preferable alkyl group is an integer of 1-8, and n is an integer of 1-10. More specifically, for example, tetraisopropyl titanate, tetra n-propyl titanate, tetra n-butyl titanate, tetra t-butyl titanate, tetraisobutyl titanate, tetraethyl titanate, tetraisooctyl titanate, mixed alkyl titanate, diisopropyl diisooctyl. Examples thereof include titanate, isopropyl triisooctyl titanate, tetra n-butyl titanate dimer condensed with tetraalkyl titanate monomer, and tetra n-butyl titanate tetramer. Of course, although not limited to those exemplified here, these titanium alkoxides may be used alone or in combination of two or more.

  Oxycarboxylic acid (B) is an organic compound having a hydroxyl group and a carboxyl group in the molecule, and is lactic acid, citric acid, glycolic acid, malic acid, tartaric acid, glyceric acid, oxypropionic acid, oxybutyric acid, oxyisobutyric acid, mandelic acid. , Trobasic acid, gluconic acid and the like. Of course, although not limited to those exemplified here, these oxycarboxylic acids can be used alone or in admixture of two or more. Of these, citric acid, malic acid, and tartaric acid provide particularly preferable results.

  The amount of oxycarboxylic acid added is required to be 0.1 mol or more per 1 mol of titanium alkoxide. The addition of the oxycarboxylic acid stabilizes the mixed solution when the aqueous titanium composition is mixed with the aqueous resin, and suppresses an abrupt reaction to give stable workability. Moreover, since the titanium content in an aqueous titanium composition will fall when the addition amount of oxycarboxylic acid is increased, it adds more preferably in the ratio of 20 mol or less.

  Examples of the aliphatic amine (C) include the following. For example, in alkylamine, methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, t-butylamine, n-amylamine, sec-amylamine, dimethylamine, diethylamine, di-n-propyl There are amine, diisopropylamine, di-n-butylamine, trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, 3- (diethylamino) propylamine, 3- (di-n-butylamino) propylamine, aliphatic Examples of cyclic amines include piperidine and pyrrolidine. Examples of alkoxyalkylamines include 3-methoxypropylamine and 3-ethoxypropylamine. Hydroxyalkylamines include N, N. Examples include dimethylethanolamine, N, N-diethylethanolamine, N, N-di-n-butylethanolamine, monoethanolamine, triethanolamine, and triisopropanolamine. Tetramethyl is used as the quaternary ammonium hydroxide. Examples include ammonium hydroxide, tetraethylammonium hydroxide, tetra-n-propylammonium hydroxide, tetra-n-butylammonium hydroxide, trimethylbenzylammonium hydroxide, 2-hydroxyethyltrimethylammonium hydroxide. Of course, although not limited to those exemplified here, these aliphatic amines may be used alone or in admixture of two or more.

  The addition amount of the aliphatic amine is required to be 0.3 mol or more with respect to 1 mol of the titanium alkoxide. However, when the addition amount of the aliphatic amine is increased, the titanium content in the aqueous titanium composition is lowered. Therefore, it is more preferably added at a ratio of 4 mol or less.

  Examples of glycol (D) include the following. For example, there are 1,2-ethanediol, 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 2,3-butanediol, 2,3-pentanediol, glycerin and the like. Of course, although not limited to those exemplified here, these glycols may be used alone or in combination of two or more.

  The addition amount of glycol is 1.0 mol or more per 1 mol of titanium alkoxide. Although it will not specifically limit if it is 1.0 mol or more, However, Since titanium content in an aqueous titanium composition will fall if an additional amount is increased, More preferably, it adds at a ratio of 6.0 mol or less.

  There is no particular limitation on the mixing order of the titanium alkoxide, aliphatic amine, and glycol. For example, there are a method of adding an aliphatic amine to titanium alkoxide and then adding glycol, a method of adding glycol to titanium alkoxide and then adding an aliphatic amine. If water is added to the composition produced by these methods, an aqueous solution containing titanium can be produced.

  There is no particular limitation on the order of mixing the oxycarboxylic acids. For example, there are a method in which oxycarboxylic acid is directly added to the aqueous titanium composition, a method in which oxycarboxylic acid is previously added to another aqueous solution, and this is mixed with the aqueous titanium composition.

  The present invention will be described in more detail with reference to the following examples, but is not limited thereto.

Preparation of Crosslinker A 28.4 g (0.1 mol) of tetraisopropyl titanate was charged into a 100 ml four-necked flask, and 29.8 g (0.2 mol) of triethanolamine was added over 30 minutes while stirring. After completion of addition, the mixture was refluxed at 85 ° C. for 30 minutes and cooled. Further, water was added to make the titanium content 1.5%, and the crosslinking agent A was used.

Preparation of cross-linking agent B The same operation as cross-linking agent B was carried out except that triethanolamine was replaced with 18.0 g (0.2 mol) of lactic acid. This solution was designated as a crosslinking agent B.

Preparation of cross-linking agent C In a 200 ml four-necked flask, 28.4 g (0.1 mol) of tetraisopropyl titanate was charged, 30.4 g (0.4 mol) of 1,2-propanediol, 25% tetramethylammonium. 36.4 g (0.1 mol as tetraethylammonium hydroxide) of an aqueous hydroxide solution was added to obtain a transparent liquid. Further, water was added to make the titanium content 1.5%, and the crosslinking agent C was used.

An aqueous solution of polyvinyl alcohol was prepared by the following method, and the insolubilization rate was measured in order to examine the crosslinking performance of the aqueous titanium composition.
A higher insolubilization rate indicates a higher degree of crosslinking.
(1) Preparation of aqueous polyvinyl alcohol solution “GOHSENOL” N-300 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was used as polyvinyl alcohol, and water was added to make a 5% aqueous solution.
(2) Film forming method After 0.7 g of malic acid was mixed with 100 g of 5% polyvinyl alcohol aqueous solution, 5.5 g of the crosslinking agent A was added and mixed. About 5 g of this was weighed in a polypropylene cup and dried at 40 ° C. for 16 hours to obtain a uniform film.
(3) Crosslinking method Each formed film was heated from 40 ° C to 200 ° C. The heating time was 30 minutes.
(4) Definition of insolubilization rate and measurement method The cross-linked membrane and about 50 ml of water were placed in a 100 ml beaker, boiled for 1 hour, and the insoluble matter was filtered using filter paper at room temperature. Then, it dried at 105 degreeC for 2 hours, the mass of filter paper and insoluble matter was measured, and the numerical value computed by the following calculation was made into the insolubilization rate.
Insolubilization rate (%) = [(c−b) / a] × 100
Where a = mass of the film before the test (g)
b = mass of filter paper (g)
c = mass of filter paper + insoluble matter (g)

  As a result of measuring the insolubilization rate, the insolubilization rate was 17% up to 120 ° C., but at 160 ° C., the insolubilization rate was 82%, and the insolubilization rate increased by 65% at a temperature difference of 40 ° C.

Comparative Example 1

  The same operation as in Example 1 was performed except that malic acid was not mixed with 100 g of a 5% polyvinyl alcohol aqueous solution.

  As a result of measuring the insolubilization rate, the insolubilization rate was 67% at 40 ° C. and crosslinking at a low temperature, and even at 200 ° C., the insolubilization rate was 91% and the insolubilization rate increased only by about 24%.

  The same operation as in Example 1 was performed except that the crosslinking agent A was replaced with the crosslinking agent B. The evaluation results are shown in Table 1.

  The same operation as in Example 2 was performed except that malic acid was replaced with 1.0 g of citric acid. The evaluation results are shown in Table 1.

  The same operation as in Example 3 was performed except that the crosslinking agent B was replaced with the crosslinking agent C. The evaluation results are shown in Table 1.

  The same operation as in Example 4 was performed except that citric acid was changed to 0.8 g of tartaric acid. The evaluation results are shown in Table 1.

  A mixture of 0.7 g of malic acid and 5.5 g of the crosslinking agent A was added to 100 g of 5% aqueous polyvinyl alcohol solution. About operation other than this, operation similar to Example 1 was performed. Although the blending order is different from that in Example 1, the insolubilization rate was 21% up to 120 ° C. as in Example 1, but the insolubilization rate was 80% at 160 ° C. and insolubilization at a temperature difference of 40 ° C. The rate increased by 59%.

  The method for crosslinking a water-based resin having a hydroxyl group in the coexistence of the water-based titanium composition of the present invention has excellent long-term stability and workability, and further can be used to arbitrarily set the cross-linking temperature. Useful.

Claims (4)

Titanium alkoxide (A) and oxycarboxylic acid (B) as essential components, oxycarboxylic acid (B), aliphatic amine (C), and general formula (I)

(Wherein R ₁ , R ₂ , R ₃ , and R ₄ are each hydrogen, an alkyl group, or a hydroxyalkyl group) one or more components selected from glycol (D) represented by In the presence of a composition having a molar ratio of oxycarboxylic acid to titanium alkoxide of 0.1 or more, the crosslinking reaction of the aqueous resin having a hydroxyl group starts at 80 ° C. to 200 ° C. A water-based resin crosslinking method, wherein the insolubilization rate is 40% or less and the insolubilization rate is increased by 50% or more at a temperature difference within 50 ° C.   A method for crosslinking a water-based resin comprising adding the cross-linking agent according to claim 1 after the oxycarboxylic acid (B) is blended in a water-based resin. Titanium alkoxide (A) and oxycarboxylic acid (B) as essential components, oxycarboxylic acid (B), aliphatic amine (C), and general formula (I)

(Wherein R ₁ , R ₂ , R ₃ , and R ₄ are each hydrogen, an alkyl group, or a hydroxyalkyl group) one or more components selected from glycol (D) represented by The method according to claim 1 or 2, wherein the composition having a molar ratio of oxycarboxylic acid to titanium alkoxide of 0.1 or more is an aqueous solution.   The method for crosslinking an aqueous resin according to claim 1, 2 or 3, wherein the aqueous resin is polyvinyl alcohol or a resin containing a vinyl alcohol unit.