JPH058735B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a water-soluble polyester resin. [Conventional technology] Polyester resin has traditionally been used in paints, adhesives,
Polyester resins that use organic solvents are widely used as anchor coating agents and in a variety of other fields, but in recent years it has been pointed out that polyester resins that use organic solvents pose problems in the working environment due to solvent odor and that the solvents may catch fire. Therefore, the demand for water-soluble polyester resins that can use water as a solvent is rapidly increasing. [Problems to be Solved by the Invention] Water solubility of such polyester resins is mainly achieved by introducing sulfonic acid groups or carboxylic acid groups into the resin, but conventional resins have poor water resistance after drying and curing. The reality is that there are few products that meet the essential properties of paints and adhesives, such as durability, alkali resistance, heat-resistant adhesion, and coating hardness, and the reality is that some performance has to be sacrificed depending on the application. . [Means for Solving the Problems] However, as a result of intensive research by the present inventors in order to eliminate the above-mentioned drawbacks of water-soluble polyester resins and to produce resins with excellent performance in various physical properties, In producing a water-soluble polyester resin containing a sulfonic acid group or a carboxylic acid group, the following general formula (However, in the formula, R ₁ represents hydrogen, an alkyl group, an alkali metal, or an ammonium ion.) When using 10 to 100 mol% of bis(4-hydroxyphenyl) acetic acids based on the polyhydric alcohol component,
The present invention was completed based on the discovery that the resin can be made into a resin with excellent water resistance, alkali resistance, heat-resistant adhesion, and coating hardness. In the present invention, the polyester resin containing a sulfonic acid group or a carboxylic acid group refers to a polybasic acid component mainly containing dicarboxylic acid, which is a condensation component of commonly known polyester resins, a polyhydric alcohol component mainly containing glycol, etc. A polybasic acid or a polyhydric alcohol having a sulfonic acid group is used in the resin, or a polybasic acid with a valence of 3 or more is subjected to a condensation reaction so that at least one carboxylic acid group remains in the resin. In the present invention, not only such means but also a carboxylic acid group may exist in the bis(4-hydroxyphenyl)acetic acid, which is a feature of the present invention, so in such a case, it is necessary to utilize such a group. is also possible. In the above, the polybasic acids having a sulfonic acid group include 5-sodiosulfoisophthalic acid, 5-
Potassium sulfoisophthalic acid, 2-sodiosulfoterephthalic acid, 2-potassium sulfoterephthalic acid, etc., and polyhydric alcohols having sulfonic acid groups are usually those obtained by reacting unsaturated polyhydric alcohols with acidic sulfites. Such unsaturated polyhydric alcohols include 3-butene-1,2-diol, 2-butene-1,4-diol, 2,5
In addition to olefin glycols such as -dimethyl-3-hexene-2,5-diol, diolefin glycols such as 1,5-hexadiene-3,4-diol can also be used. Among these compounds, 2-sodiosulfoterephthalic acid and 5-sodiosulfoisophthalic acid are most preferably used. Examples of trivalent or higher polybasic acids include trimellitic acid, trimellitic anhydride, pyromellitic acid, 4-methylcyclohexene-1,2,3 tricarboxylic anhydride, trimesic acid, and the like. From the viewpoint of water solubility, the content of sulfonic acid groups or carboxylic acid groups in the resin should be such that the acid value of the resin is at least
20KOHmg/g, more preferably 20-200KOH
It is necessary to introduce it so that it becomes mg/g.
However, the acid value referred to in this application is calculated based on free groups including those introduced into the resin as sulfonate or carboxylic acid bases. Hereinafter, the polyester resin of the present invention will be specifically explained by dividing it into bis(4-hydroxyphenyl)acetic acids, polyhydric alcohol component, and polybasic acid component. First, the most important feature of the present invention is that bis(4-hydroxyphenyl)acetic acids represented by the following general formula are used as the condensation component of the water-soluble polyester resin. However, in the formula, R ₁ represents hydrogen, an alkyl group, an alkali metal or an ammonium ion. The number of carbon atoms in the alkyl group is not particularly limited, but is usually 1 to 1.
10, and is any linear or branched alkyl group. As the alkali metal, sodium and potassium ions can be used, and as the ammonium ion, quaternary ammonium salts can also be used. Among the compounds shown above, a particularly practical example is bis(4-hydroxyphenyl).
Acetic acid, methyl bis(4-hydroxyphenyl) acetate, ethyl bis(4-hydroxyphenyl) acetate, n-propyl bis(4-hydroxyphenyl) acetate, n-bis(4-hydroxyphenyl) acetate
-butyl, etc., but are not necessarily limited to these. Such bis(4-hydroxyphenyl)acetic acids can be obtained by reacting glyoxylic acid with the corresponding phenols in the presence of a mineral acid or a strongly acidic ion exchange resin, and further esterifying it as necessary.
Alternatively, it can be easily prepared by reacting glyoxylic acid ester with the corresponding phenol. The content of the above-mentioned bis(4-hydroxyphenyl)acetic acids in the resin is 10 to 100 mol%, more preferably 30 to 80 mol% of the entire polyhydric alcohol component.
Use mole%. If the content of bis(4-hydroxyphenyl)acetic acids is too small outside this range, the effect of improving various physical properties such as water resistance and alkali resistance will be insufficient, making it impractical. However, even within this range, the acid value of the entire resin needs to be within the range mentioned above, so when manufacturing the resin, the charging composition and the R ₁ of bis(4-hydroxyphenyl)acetic acids should be adjusted. Care must be taken in selection. Next, polyhydric alcohol components other than the above-mentioned bis(4-hydroxyphenyl)acetic acids include ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 2,4-dimethyl-2-ethylhexane-
1,3-diol, 2,2-dimethyl-1,3-
Propanediol (neopentyl glycol),
2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 1,3-butanediol, 1,
4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, 1,2-
Cyclohexane dimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-
1,3-cyclobutanediol, 4,4'-thiodiphenol, 4,4'-methylene diphenol,
4,4′-(2-norbornylidene)diphenol,
4,4'-dihydroxybiphenol, o-,m-
and p-dihydroxybenzene, 4,4'-isopropylidene diphenol, 4,4'-isopropylidene bis(2,6-dichlorophenol), 2,
Mention may be made of 5-naphthalenediol and p-xylene diol. In addition to the above, trivalent or higher polyhydric alcohols such as pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, trimethylolpropane, trimethylolethane, 1,3,6-hexanetriol, etc. can also be used in small amounts. be. Polybasic acid components include terephthalic acid, isophthalic acid, malonic acid, dimethylmalonic acid, succinic acid,
Glutaric acid, adipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, itaconic acid, 1,3-cyclopentanedicarboxylic acid, 1,2- Cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid,
1,4-cyclohexanedicarboxylic acid, 2,5-
Norbornanedicarboxylic acid, 1,4-naphthalic acid, diphenic acid, 4,4'-oxybenzoic acid, diglycolic acid, thiodipropion, and 2,5-
Examples include naphthalene dicarboxylic acid. These may be acid anhydrides, esters, chlorides, etc., such as dimethyl 1,4-cyclohexanedicarboxylate, dimethyl 2,6-naphthalene dicarboxylate, dimethyl isophthalate, dimethyl terephthalate, dimethyl terephthalate, and diphenyl terephthalate. including. Therefore, when producing the water-soluble polyester resin of the present invention, the total amount of the above-mentioned bis(4-hydroxyphenyl)acetic acids and other polyhydric alcohols mainly composed of glycols per mole of polybasic acid,
Each condensation component is charged in a proportion of 0.8 to 2.0 moles, and the esterification/condensation reaction is carried out by a commonly known method. The reaction conditions are not particularly limited, but generally the esterification/condensation reaction is carried out at a temperature of 180 to 250°C, and then, if necessary, the temperature is 220 to 280°C and 5 to 0.1 mm.
It is efficient to carry out the condensation reaction continuously under a reduced pressure of about Hg. The reaction is carried out in an organic solvent system such as trichlene, toluene, xylene, etc. as necessary, and an organic solvent such as dibutyltin laurate, dibutyltin di-2-ethylhexoate, iron acetylacetonate, etc. is used to accelerate the reaction. compounds, metal chlorides such as stannous chloride and ferric chloride,
Catalysts such as tertiary amines such as N,N'-dimethylaniline and triethanolamine can be used. The water-soluble polyester resin thus obtained may contain an ethylenically unsaturated monomer having a functional group such as a hydroxyl group or a carboxylic acid group for the purpose of imparting radical curability, as long as the water-soluble property is not lost. For the purpose of imparting air curability to the oligomer or polymer, a polyhydric alcohol having an allyl ether group may be used as a third condensation component other than the above, or a post-reaction may be carried out after the production of the polyester resin. Addition to a group capable of reacting with the compound, such as a carboxylic acid group, is also a useful means. The preferred content of the compound in the resin is about 0.1 to 0.3 mol per functional group in the resin. As the ethylenically unsaturated monomer, 2-hydroxy (meth)acrylate,
2-hydroxypropyl (meth)acrylate,
2-hydroxyethyl acryloyl phosphate, N-methylol (meth)acrylamide, ethylene glycol monoacrylate, dipropylene glycol monoacrylate, etc. are used.
Further, as the polyhydric alcohol having an allyl ether group, pentaerythritol triallyl ether, pentaerythritol diallyl ether, pentaerythritol monoallyl ether, trimethylolpropane diallyl ether, trimethylolpropane monoallyl ether, trimethylolethane diallyl ether, trimethylol Ethane monoallyl ether, glycerin diallyl ether, glycerin monoallyl ether, hexanetriol diallyl ether, hexamethylol melamine tetraallyl ether, etc. are used. The water-soluble polyester resin produced by the above method is used after being dissolved in an aqueous solvent. Water is generally used as the aqueous solvent, but other solvents that are compatible with water, lower alcohols, etc. can also be used in combination. The concentration of the solution may be adjusted as appropriate depending on the purpose, but it is usually used in a range of 5 to 50% by weight in terms of resin solid content. When dissolving, if the sulfonic acid groups or carboxylic acid groups in the resin are free, the resin is neutralized in advance in an alkaline aqueous solution or ammonia aqueous solution, and the sulfonic acid groups and carboxylic acid groups in the resin are converted into salt form. It is necessary to. Depending on the purpose or the resin composition of the polyester resin, the aqueous solution may contain any conventionally known plasticizers, pigments, fillers, stabilizers, diluents, anti-greening agents, crosslinking monomers, crosslinking accelerators, A polymerization initiator can be added. It is of course also possible to blend the resin with other known resins as long as the effects of the present invention are not impaired. [Effects] The water-soluble polyester resin obtained by the present invention can be used for various purposes such as water-based paints, water-based adhesives, anchor coating agents, construction materials, films, molded products, fiber glues, etc. All products have excellent physical properties such as water resistance, alkali resistance, heat-resistant adhesion, and hardness. [Example] Hereinafter, the present invention will be explained in more detail with reference to Examples. In the examples, "parts" or "%" are based on weight unless otherwise specified. For simplicity, "bis(4-hydroxyphenyl)acetic acids" will be referred to as "BHPA" below. For example, "BHPA(R ₁ :H)" means that R ₁ is in the general formula of BHPA in the text. Indicates hydrogen. In the examples, the acid value, hydroxyl value, and number average molecular weight were calculated using the following formulas. For acid values, carboxylic acid groups or sulfonic acid groups are considered to be free groups. Also shown. ●Acid value (AV) AV (KOHmg/g) = (a-b) x 5.611 x f/wa a (mg): Titration amount of sample (resin) b (mg): Titration amount of blank w (g): Weight of sample f: Potency of 0.1N KOH normal solution used ● Hydroxyl value (OHV) OHV (KOHmg/g) = 5.611 x (ba-a) x f/w + AV a, b, f, w are as above Same Number average molecular weight (Mn) Mn=56.11×1000/OHV×m m: Total number of carboxylic acid groups and hydroxyl groups in one molecular weight of resin Example 1 Equipped with a stirrer, rectification column, nitrogen introduction tube, and vacuum device In the reactor, terephthalic acid/isophthalic acid/ethylene glycol/BHPA (R ₁ :Na) = 0.5/0.5/
0.9/0.6 (molar ratio, all preparation ratios below are molar ratios)
In addition, dibutyltin laurate 0.1
% as a catalyst and carried out the esterification reaction at 160 to 230°C for 5 hours, followed by 5 to 0.1 mmHg, 220 to 280
Condensation was carried out at ℃ for 5 hours to obtain AV2 (90), OHV6,
A water-soluble polyester resin with Mn 18000 was obtained. The obtained resin was dissolved in water to a resin solid content concentration of 30
%, and a viscosity of 40 cps/20°C (the conditions for the resin liquid are the same below) was prepared. This is made of acrylic plastic board (3mm thick)
It was coated on top using a roll coater so that the film thickness after drying was 20μ, and dried at a temperature of 120°C for 20 minutes. The resulting coating film has water resistance, alkali resistance,
Heat resistant adhesion and hardness were evaluated. The evaluation method and results are shown in the table. Examples 2 to 4 In Example 1, resins were produced by changing the types of raw materials and their charging ratios as shown below, and their performance was evaluated. However, the resin of Example 2 was subjected to performance evaluation after being neutralized with a 5% aqueous sodium hydroxide solution. Resin of Example 2 Terephthalic acid/Isophthalic acid/Ethylene glycol/BHPA (R ₁ :H)=0.5/0.5/0.7/0.4 AV90, OHV65, Mn1200 Resin of Example 3 Terephthalic acid/Isophthalic acid/5-Sodiosulfo Isophthalic acid/ethylene glycol/diethylene glycol/BHPA (R ₁ :NH ₄ )=0.48/0.45/
0.07/1.0/0.3/0.2 AV1.5(20), OHV25, Mn4500 Resin of Example 4 Terephthalic acid/Isophthalic acid/5-Sodiosulfoisophthalic acid/Ethylene glycol/BHPA
(R ₁ :CH ₃ )=0.45/0.45/0.10/0.9/0.6 AV2.1 (22), OHV15, Mn7500 The results of Examples 2 to 4 are summarized in the table. Comparative Example In Example 4, a water-soluble polyester resin was produced using ethylene glycol instead of BHPA, and its performance was evaluated according to the same example. Record the results in the table. Example 5 According to Example 2, the resin composition was terephthalic acid/isophthalic acid/ethylene glycol/BHPA (R ₁ :
H)=0.5/0.5/0.8/0.3 carboxylic acid group-containing polyester resin (AV81, OHV62, Mn1200) was produced and diluted with xylene, and then 2-hydroxyethyl acrylate was added per mole of carboxylic acid group.
The mixture was charged at a ratio of 0.4 mol, and the addition reaction was carried out at a temperature of 90°C. The obtained resin has AV50, OHV60,
Mn1300 was dissolved in 2% aqueous ammonia to neutralize the carboxylic acid groups to obtain a resin liquid of water-soluble polyester resin. To 100 parts by weight of the resin liquid, 0.5 part of cobalt acetate (5% cobalt content) was added as an accelerator, and 30 parts of a 5% aqueous hydrogen peroxide solution was added as a hardening agent, and a plastic board was prepared in the same manner as in Example 1. and cured at 60°C. The curing speed was very good, taking 20 minutes by touch test. The performance of the resulting coating film was evaluated. The results are shown in the table. Example 6 In Example 5, trimethylolpropane diallyl ether was charged in place of 2-hydroxyethyl acrylate at a ratio of 0.2 mole per mole of carboxylic acid group, and the same reaction as in Example 5 was carried out. The resulting resins were AV57, OHV61, and Mn1400, and were neutralized with a 4% aqueous sodium hydroxide solution to obtain a resin liquid of water-soluble polyester resin. Thereafter, the resin liquid was applied to a plastic board in the same manner as in Example 1 and cured at 60°C, and was completely cured in about 25 minutes. The performance of the resulting coating film was evaluated. The results are shown in the table. 【table】

Claims (1)

[Scope of Claims] 1. In producing a water-soluble polyester resin containing a sulfonic acid group or a carboxylic acid group, the following general formula (wherein R ₁ represents hydrogen, an alkyl group, an alkali metal, or an ammonium ion) is used. 1. A method for producing a water-soluble polyester resin, which comprises using bis(4-hydroxyphenyl)acetic acids in an amount of 10 to 100 mol% based on the polyhydric alcohol component.