JPH1095837A - Production of aqueous polyester dispersion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that a stable aqueous dispersion adaptable to a coating material, an ink, etc., could not be obtained from a polyester synthesized from a cyclic acid anhydride, an epoxide and a hydroxylated compound in the presence of a basic catalyst. SOLUTION: A polyester is produced by reacting a substantially equimolar mixture of a cyclic acid anhydride (A) having one acid anhydride group in the molecule with an epoxide (B) having one epoxy group in the molecule in the presence of a compound (C) having at least one hydroxyl group in the molecule by using a basic catalyst (D) comprising, e.g. a tertiary amine. The amount of the compound C is less than 0.5mol per mol of the compound A or B, a part or all of the compounds A, B and C have carboxyl groups, and the polyester has an acid value of 5 to 100 before being neutralized. A part or all of the carboxyl groups of the polyester are neutralized to give an aqueous dispersion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyester which is excellent in pigment dispersibility, adhesion to a substrate, and gloss retention, and which can be used as a paint, ink and adhesive. More specifically, the present invention relates to a method for producing an aqueous polyester dispersion which can be polymerized at a reaction temperature of 100 ° C. or lower and is self-emulsified by neutralization treatment and can be dispersed in water. The polyester aqueous dispersion of the present invention is useful as a paint, an ink, an adhesive, a building material base treatment agent and a finishing agent, a paper treatment agent,
Particularly, it is useful as a paint or ink for a polyester film.

[0002]

2. Description of the Related Art Polyester has very good adhesion to polyester films such as PET and PBT.
It is used in large quantities as a polymer for paints, inks and adhesives. Polyester synthesis methods for this purpose include a method of synthesizing a dibasic acid and glycol by dehydration condensation, a method of synthesizing a dibasic acid ester and glycol by transesterification, and a method of ring-opening polymerization of a cyclic acid anhydride and an epoxide. There are methods. Among the above methods, the method of synthesizing by ring-opening polymerization from a cyclic acid anhydride and an epoxide is the only polyester synthesis method that can be synthesized at a reaction temperature of 100 ° C. or less, and has the advantage that production equipment is very simple. There is.

The inventors of the present invention have been studying a method of synthesizing a polyester by ring-opening polymerization of a cyclic acid anhydride and an epoxide (JP-A-61-47728, JP-A-61-126128). Publications), paints, inks, and adhesives that do not use an organic solvent have been demanded in consideration of the environment, and it has been expected to supply the polyester as an aqueous dispersion. However, it is very difficult to prepare an aqueous dispersion of polyester because the polyester itself has poor self-emulsifying ability, and a good aqueous dispersion has not been obtained.

[0004]

In view of the above circumstances, the present invention utilizes a ring-opening polymerization of a cyclic acid anhydride and an epoxide to synthesize a polyester at a reaction temperature of 100 ° C. or lower, and furthermore, prepares the polyester in water. Of the present invention is to establish a method for producing an aqueous polyester dispersion in which is dispersed stably.

[0005]

The first invention comprises a cyclic acid anhydride (A) having one acid anhydride group in one molecule and an epoxide (B) having one epoxy group in one molecule. ),
(A) and (B) are substantially equimolar in the presence of a compound (C) having one or more hydroxyl groups in one molecule, and reacted by using a basic catalyst (D) as a catalyst. (A) or (B) 1
(C) is less than 0.5 mol per mol, and the above (A)
(B) A part or all of (C) has a carboxyl group, the acid value of the polyester before neutralization is 5 to 100, and a part or all of the carboxyl group is neutralized to form an aqueous dispersion. A method for producing a polyester aqueous dispersion.

The second invention is the process for producing a polyester aqueous dispersion according to the first invention, wherein the basic catalyst (D) is a tertiary amine. The third invention is the method for producing a polyester aqueous dispersion according to any one of the first and second inventions, wherein the compound (C) having one or more hydroxyl groups in one molecule is a glycol. . A fourth invention is the method for producing a polyester aqueous dispersion according to any one of the first to third inventions, wherein part or all of the cyclic acid anhydride (A) is trimellitic anhydride. In the fifth invention, a part or all of the cyclic acid anhydride (A) having one or more acid anhydride groups in one molecule is contained in one molecule.
A cyclic acid anhydride having at least two carboxyl groups,
The method for producing a polyester aqueous dispersion according to any one of the first to fourth inventions, wherein the aqueous dispersion contains 3 to 60 mol% of the total cyclic acid anhydride.

In a sixth aspect, a cyclic acid anhydride (A) having one acid anhydride group in one molecule and an epoxide (B) having one epoxy group in one molecule are represented by (A) And (B) are substantially equimolar in the presence of a compound (C) having one or more hydroxyl groups in one molecule, in the presence of a basic catalyst (D) as a catalyst, and 5 to 50 parts by weight based on the total weight. A method for producing a polyester aqueous dispersion according to any one of claims 1 to 4, wherein the polymerization is carried out at a reaction temperature of 100 ° C or lower in the presence of an organic solvent (E) having a boiling point of 100 ° C or lower by weight.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is derived from a detailed study of a polyester synthesis method using a cyclic acid anhydride, an epoxide, and a hydroxyl group-containing compound as starting materials and a ring-opening polymerization using a basic catalyst. is there. The polyester production method of the present invention comprises: (A) a cyclic acid anhydride (A) having one acid anhydride group in one molecule and an epoxide (B) having one epoxy group in one molecule. (B) is a synthesis method obtained by reacting a substantially equimolar amount of a compound (C) having one or more hydroxyl groups in one molecule with a basic catalyst (D) as a catalyst. The reaction formula is as follows.

[0009]

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The compound (C) having one or more hydroxyl groups in one molecule functions as a reaction terminator and is incorporated into the terminal structure of the polyester. The average molecular weight of the polyester can be controlled by the amount of compound (C) charged. The smaller the amount of compound (C), the higher the average molecular weight. The reaction is a polyester polymerization reaction by ring-opening polymerization of a cyclic acid anhydride (A) and an epoxide (B) using a basic catalyst (D) as a catalyst.

[0011] In the above polyester production method,
(A) and (B) are substantially equimolar, and (C) is less than 0.5 mol per 1 mol of (A) or (B). Part or all of the polyester has a carboxyl group, the acid value of the polyester before neutralization is 5 to 100, and a part or all of the carboxyl group is neutralized to form an aqueous dispersion. The present invention provides a method for producing a polyester aqueous dispersion.

The cyclic acid anhydride (A) having one acid anhydride group in one molecule is an intramolecular anhydride of a polycarboxylic acid, and is a saturated or unsaturated aliphatic polycarboxylic anhydride. Products, alicyclic polycarboxylic anhydrides, aromatic polycarboxylic anhydrides, etc., or part of these are substituted with saturated or unsaturated hydrocarbon groups, aromatic ring groups, halogen atoms, heterocyclic groups, etc. Something was done. Specific examples of these include succinic anhydride, phthalic anhydride, maleic anhydride, itaconic anhydride, citraconic anhydride, glutaric anhydride, dodecenyl succinic anhydride, chlorendex anhydride, trimellitic anhydride, hexahydrophthalic anhydride, Methylhexahydrophthalic anhydride, tetramethylene maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride,
5- (2,5-dioxotetrahydroxyfuryl) -3
-Methyl-3-cyclohexene-1, 2-dicarboxylic anhydride, methylnadic anhydride, glycerol tris (anhydrotrimellitate), ethylene glycol bis (anhydrotrimellitate) and the like. Among these, as the cyclic acid anhydride having a carboxyl group,
There are tricarboxylic anhydrides, such as trimellitic anhydride, with trimellitic anhydride being particularly suitable for making good aqueous dispersion solutions. Cyclic acid anhydrides such as pyromellitic anhydride having two or more acid anhydride groups in one molecule are not preferred because they cause a cross-linking reaction at the time of polyester synthesis and cause gelation.

The epoxide (B) having one epoxy group in one molecule includes a saturated or unsaturated aliphatic epoxide, an alicyclic epoxide, an aromatic epoxide or the like having an epoxide structure in the molecule. Is partially substituted with a saturated or unsaturated hydrocarbon group, aromatic ring group, halogen atom, heterocyclic group, or the like. Specific examples of these include ethylene oxide, propylene oxide, epichlorohydrin, styrene oxide, epibromohydrin, phenylglycidyl ether, allyl glycidyl ether, cyclohexene oxide, glycidyl acrylate, glycidyl methacrylate, butene oxide, butyl glycidyl ether, cresyl glycidyl Ether and alkylphenol glycidyl ether. Diglycidyl ether compounds having two or more epoxy groups in one molecule are not preferred because they cause a crosslinking reaction during the synthesis of polyester and cause gelation.

The compound (C) having one or more hydroxyl groups in one molecule includes aliphatic saturated compounds such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, pentanol and hexanol. Aliphatic unsaturated alcohols such as alcohol, allyl alcohol, crotyl alcohol, and propargyl alcohol; alicyclic alcohols such as cyclopentanol and cyclohexanol; aromatic alcohols such as benzyl alcohol and cinnamyl alcohol; furfuryl alcohol; tetrahydro Heterocyclic alcohols such as furfuryl alcohol, and glycols such as ethylene glycol, propylene glycol, 1,4-butylene glycol, butenediol, hexanediol, cyclohexanediol, and diethylene glycol Le, glycerine, a triol such as trimethylol propane, bisphenol A, phenol, o- cresol, m- cresol, a compound having an alcoholic or phenolic hydroxyl groups, such as phenols such as p- cresol. Among them, ethylene glycol, propylene glycol, 1,
For glycols such as 4-butylene glycol, butenediol, hexanediol, cyclohexanediol, and diethylene glycol, when one hydroxyl group reacts, the remaining hydroxyl groups are extremely reduced in reactivity and synthesize a polyester having hydroxyl groups at both ends. Therefore, it is suitable for obtaining a stable solution as an aqueous dispersion.

Examples of the basic catalyst (D) include tertiary amines such as N, N-dimethylbenzylamine, triethylamine, tributylamine, N, N-diethylaniline, N, N-dimethylaniline, sodium acetate, potassium acetate and the like. Strong alkali organic acid salts, and strong alkalis such as sodium hydroxide and potassium hydroxide. Among these basic catalysts, tertiary amines are suitable for catalysis of the ring-opening polymerization of cyclic acid anhydrides and epoxides, so that the reaction can be easily controlled and a transparent resin can be obtained. Is preferred.

In the polymerization reaction of the polyester of the present invention, the hydroxyl group of the compound (C) and the acid anhydride group of the cyclic acid anhydride (A) activated by a basic catalyst react first and then preferentially. , A carboxyl group generated by this reaction,
It reacts with the epoxy group of the epoxide (B) activated by the basic catalyst to generate a secondary hydroxyl group. Further, the same reaction as described above can be allowed to proceed sequentially, such that the generated hydroxyl group reacts with the acid anhydride group of the cyclic acid anhydride (A). The details of this reaction are described in
-47728 and JP-A-61-126128. In this reaction, by adjusting the amounts of the cyclic acid anhydride (A) and the epoxide (B) to be reacted with respect to the amount of the compound (C), the compound (C) is terminated at a desired length. Polyester can be made. The proportion of each compound is such that the cyclic acid anhydride (A) and the epoxide (B) are almost equimolar, and the compound (C) is 1 mol relative to the cyclic acid anhydride (A) or the epoxide (B). , Less than 0.5 mole. When the amount of the compound (C) is more than 0.5 mol,
Necessary properties cannot be obtained due to the low molecular weight of the resulting polyester and the residual compound (C). Compound (C)
When the amount is 0 mol, the molecular weight becomes too large and control of the reaction becomes difficult.

In order to make the polyester into an aqueous dispersion, some or all of (A), (B) and (C) have a carboxyl group, and some or all of these are neutralized. The acid value of the polyester before neutralization is 5 to 100, preferably 20 to 90. When the acid value is less than 5, the affinity for water is poor and a good aqueous dispersion is not obtained. When the acid value is larger than 100, the viscosity of the polyester is significantly increased, which is not preferable. When a part or all of the cyclic acid anhydride (A) is a cyclic acid anhydride having one or more carboxyl groups in one molecule, the cyclic acid having a carboxyl group is compared with the total cyclic acid anhydride. Preferably, the anhydride is 3 to 60 mol%. When the amount of the cyclic acid anhydride having a carboxyl group deviates from the range of 3 to 60 mol%, it becomes difficult for the synthesized polyester to have a predetermined acid value, which is not preferable. For neutralization, amines such as aqueous ammonia, sodium hydroxide, potassium hydroxide, dimethylaminoethanol, and triethylamine are used. A part or all of the carboxyl groups are neutralized, but it is preferable to adjust the pH to a range of 5 to 10. The neutralization operation is performed by adding a certain amount of water at 60 ° C. or lower after the polyester polymerization. For the purpose of improving water dispersibility, a hydrophilic solvent such as isopropyl alcohol or an emulsifier may be used in combination.

Cyclic anhydride (A) and epoxide (B)
In the presence of a compound (C) having (A) and (B) in substantially equimolar amounts and having one or more hydroxyl groups in one molecule, using a basic catalyst (D) as a catalyst, 5 to
Polymerization can be carried out at a reaction temperature of 100 ° C or lower in the presence of 50% by weight of an organic solvent (E) having a boiling point of 100 ° C or lower.
As the organic solvent (E), generally used solvents such as ethyl acetate, MEK, and toluene can be used, but those having active hydrogen such as alcohols cannot be used. This reaction can be carried out in the presence or absence of a suitable organic solvent, but an organic solvent can be added to facilitate the control of the reaction. If the amount of the organic solvent is more than 50% by weight, the reaction rate becomes extremely slow, and the amount of residual monomer increases, which is not preferable. If the amount of the organic solvent is less than 5% by weight, the polymerization reaction is too fast, and it is difficult to control the reaction.

[0019]

The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Parts and% in Examples and Comparative Examples represent parts by weight and% by weight.

Example 1 0.8 mol of hexahydrophthalic anhydride and 0.2 mol of trimellitic anhydride as a cyclic acid anhydride, 1.0 mol of butyl glycidyl ether as an epoxide, 0.1 mol of ethylene glycol as a compound having a hydroxyl group Then, 0.02 mol of dimethylbenzylamine as a basic catalyst was put into a reaction vessel, and the mixture was stirred at 90 ° C. for 5 hours under a normal pressure and a nitrogen atmosphere. The molecular weight of the reactants was measured by GPC. The end of the reaction was determined by IR absorption at 1850c in the IR spectrum.
It was confirmed that m- ¹ disappeared. Distilled water was added to the obtained polyester so as to have 0.2 mol of triethylamine and a solid content of 30% by weight, and the mixture was stirred vigorously to obtain a polyester aqueous dispersion. The aqueous dispersion stability test was performed by a predetermined method. The results are shown in Table 1.

Examples 2 to 10 The same operation as in Example 1 was carried out except that the raw materials used were changed as shown in Table 1, and the results were obtained. The results are shown in Table 1. Comparative Example 1 The same operation as in Example 1 was carried out except that the hexahydrophthalic anhydride was changed to 0 mol and the trimellitic anhydride was changed to 1.0 mol. The results are shown in Table 1. Comparative Example 2 In Example 1, hexahydrophthalic anhydride was added in an amount of 1.0%.
Mol and trimellitic anhydride were 0 mol. Neutralization was not performed, and the rest of the procedure was the same. The results are shown in Table 1.

[0022]

[Table 1]

HHPA: hexahydrophthalic anhydride TMA: trimellitic anhydride PAH: phthalic anhydride GAH: glutaric anhydride BGE: butyl glycidyl ether PGE: phenyl glycidyl ether EG: ethylene glycol TEA: triethylamine DMAE: dimethylaminoethanol

Example 11 As in Example 1, 0.8 mol of hexahydrophthalic anhydride and 0.2 mol of trimellitic anhydride were used as the cyclic acid anhydride, and butyl glycidyl ether 1.0 was used as the epoxide.
Mol, 0.1 mol of ethylene glycol as a compound having a hydroxyl group, and 0.02 mol of dimethylbenzylamine as a basic catalyst are placed in a reaction vessel, and ethyl acetate is added so as to be 25% by weight of the whole. It carried out like Example 1. The obtained polyester had the same average molecular weight, acid value, water resistance and aqueous dispersion stability as those synthesized in Example 1.

Comparative Example 3 The procedure of Example 11 was repeated, except that ethyl acetate was added to make up 60% of the whole. However, after 5 hours, the amount of unreacted substances was large and the reaction was not completed.

The physical properties of the aqueous polyester dispersion were tested according to the following test methods. <Measurement of average molecular weight> The average molecular weight was measured using gel permeation chromatography. For the determination of the molecular weight, commercially available monodisperse polystyrene was used as a standard sample. <Measurement of Acid Value> The acid value was measured according to the method specified in JIS K 0070-1966.

<Aqueous dispersion stability test> A polyester synthesized by a predetermined method was neutralized with amines to obtain a solid content of 30%.
The polyester aqueous dispersion solutions prepared in Examples and Comparative Examples were allowed to stand at 40 ° C. for 24 hours, and the state of separation of the polymer and water was observed. The criteria are as follows. ：: No separation was observed at all. Δ: Separation was observed, but a good dispersion was obtained again with stirring. X: Even if it is completely separated and stirred, it does not disperse again.

[0028]

The present invention provides a method for producing an aqueous dispersion of a polyester having curability. Polyester has poor self-emulsifying properties, and it was difficult to prepare an aqueous dispersion.However, a stable dispersion was obtained by adjusting the acid value, and an aqueous paint made using the polyester aqueous dispersion of the present invention was transparent. Not only does it provide a film and is excellent in pigment dispersibility and can be easily formed into a paint, but when used as a resin for aqueous gravure ink, it has good adhesion to the underlying polyester film.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Makoto Takano Minami Toyo Ink Manufacturing Co., Ltd. 2-3-13 Kyobashi, Chuo-ku, Tokyo

Claims (6)

[Claims] 1. A cyclic acid anhydride (A) having one acid anhydride group in one molecule and an epoxide (B) having one epoxy group in one molecule are obtained by combining (A) and (B) Are substantially equimolar in the presence of a compound (C) having one or more hydroxyl groups in one molecule, using a basic catalyst (D) as a catalyst,
In the method for producing a polyester obtained by reacting,
(C) is less than 0.5 mole relative to 1 mole of (A) or (B), and part or all of (A), (B) and (C) have a carboxyl group, and A method for producing an aqueous polyester dispersion, wherein the polyester has an acid value of 5 to 100, and a part or all of the carboxyl groups are neutralized to obtain an aqueous dispersion. 2. The method for producing a polyester aqueous dispersion according to claim 1, wherein the basic catalyst (D) is a tertiary amine. 3. The method for producing a polyester aqueous dispersion according to claim 1, wherein the compound (C) having one or more hydroxyl groups in one molecule is a glycol. 4. The method according to claim 1, wherein part or all of the cyclic acid anhydride (A) is trimellitic anhydride.
4. The method for producing a polyester aqueous dispersion according to any one of claims 1 to 3. 5. The cyclic acid anhydride (A) having one or more acid anhydride groups in one molecule is a cyclic acid anhydride having one or more carboxyl groups in one molecule. The method for producing a polyester aqueous dispersion according to any one of claims 1 to 4, comprising 3 to 60 mol% of the total cyclic acid anhydride. 6. A cyclic acid anhydride (A) having one acid anhydride group in one molecule and an epoxide (B) having one epoxy group in one molecule, comprising: (A) and (B) Are substantially equimolar, in the presence of a compound (C) having one or more hydroxyl groups in one molecule, using a basic catalyst (D) as a catalyst, and having a boiling point of 5 to 50% by weight based on the total weight. The method for producing a polyester aqueous dispersion according to any one of claims 1 to 5, wherein the polymerization is performed at a reaction temperature of 100 ° C or lower in the presence of an organic solvent (E) of 100 ° C or lower.