JPS59197426A - Production of polyester resin having epoxy group - Google Patents

Abstract

PURPOSE:To obtain a polyester resin having a plurality of epoxy groups on its terminals and being excellent in weather resistance, etc., by reacting a polyester- polycarboxylic acid having a plurality of carboxyl groups on its terminals with a specified diepoxide. CONSTITUTION:A polybasic acid such as terephthalic or fumaric acid is reacted with a polyhydric alcohol such as ethylene glycol or bisphenol A to produce a polyester-polycarboxylic acid having at least two carboxyl groups on its terminals, with an MW of 400-10,000, and acid value of 10-30mg KOH/g. The product is reacted with a diepoxide of the formula (wherein R and R' are each H or a lower alkyl), e.g., vinylcyclohexene diepoxide or limonene diepoxide, to obtain the purpose polyester resin having a plurality of epoxy groups at its terminals.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyester resin having at least two or more epoxy groups at its terminals.

More specifically, it relates to a method for producing a polyester resin having excellent light resistance and having an epoxy group at the end obtained by adding 1 mole of a diepoxide having a specific structure to one terminal carboxyl group of a polyester polycarboxylic acid.

Generally, epoxy resins have excellent physical properties such as adhesiveness and chemical resistance, and are therefore used as adhesives.

Widely used in paints, laminated materials, molding materials, etc.

Furthermore, solid epoxy resins are used as components for powder coatings. For example, solid epoxy resins derived from the most representative epoxy resins, epichlorohydrin and bisphenol/L'A, are actually used as powder coating components, but they are obtained by curing them. The coating film is not necessarily satisfactory in terms of weather resistance, impact resistance, etc. Furthermore, as a method for obtaining a solid epoxy resin, for example, a method is known in which a low molecular weight bifunctional epoxy resin is added to the terminal carboxyl group of a polyester polycarboxylic acid, but in this reaction, the polyester polycarboxylic acid and the epoxy resin A polymeric resin is produced in which the epoxy resin is alternately bonded, and the product gels during the reaction, or even if gelation does not occur, a resin with a wide molecular weight distribution containing unreacted epoxy resin is produced. However, it has been extremely difficult to obtain a solid epoxy resin with a narrow molecular weight distribution that can be used as a powder coating component.

The present inventors investigated a method for producing an epoxy resin component for powder coatings with excellent weather resistance, and found that when polyester polycarboxylic acid is reacted with dieboxide having a specific structure, the formation of high molecular weight resin is avoided. It has been found that a solid product containing 1 mole of gepoxide is produced for each terminal μ-phoxyl group of the polyester polycarboxylic acid, and that this product is extremely useful as a component for powder coatings. As a result of further study, the present invention was arrived at.

That is, the present invention has a molecular weight of 400 to 10,000 and an acid value of 10-3.
00WxoH1f Reacting a polyester polycarboxylic acid having two or more carboxyl groups at a certain terminal with a diepoxide represented by the general formula (I'l, R' are the same or different and are hydrogen atoms or lower alkyl). This is a method for producing a polyester resin having at least two or more epoxy groups at the end thereof.

The polyester polycarboxylic acid used in the present invention is a known resin that can be produced by a conventional method using a polybasic acid or its anhydride and a polyhydric alcohol as raw materials. Polybasic acids include, for example, tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, maleic acid, tumeric acid, succinic acid, glutaric acid, adipic acid, and azelaic acid. acid, sepacic acid, decanedicarboxylic acid, lid μ
Acids include terephthalic acid, isophthalic acid, trimellitic acid, and mixtures of these polybasic acids (or their anhydrides) may be used.

Examples of polyhydric alcohols include 1,4-cyclohexanedimethanol-μ, 1,4-cyclohexanediol, hydrogenated bisphenol A, SPIPF Ricoh/l/, ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, Examples include decanediol, neopentyl glyco-p, glycerin, trimethylolpropane, hydroxypiparate neopentyl glycol ester μ, bispheno-/L'A, etc., and using a mixture of these polyhydric alcohols, Good too.

By appropriately combining these polybasic acids (anhydrides thereof) and polyhydric alcohols, various polyester polycarboxylic acids can be produced.

Among these polyester polycarboxylic acids, particularly preferred are those having 2 to 4 poxy groups at the end, a molecular weight of 800-4000, and an acid value of 50-4000.
200m+fKOH,i.

The diepoxide represented by the general formula CI) used in the present invention includes diepoxides in which the lower alkyl represented by R and R' is, for example, methyl, ethyl, etc., and specifically, for example, vinylcyclohexene. Dioxide (R and I'l' are both hydrogen atoms), limonene dioxide (R and R' are both methy/l'), and the like can be used.

In the present invention, the above two raw materials are mixed and subjected to an addition reaction upon heating. Theoretically, the amount of these raw materials used is such that the number of epoxy groups in the diepoxide is 2 relative to the number of carboxyl groups in the polyester polycarboxylic acid, but in actual reaction, it is approximately 1.5 or more, preferably about 1.5 or more. An amount in the range of 1.8 to 4 is used, and if excess diepoxide is used, it may be removed after the reaction, for example, by extraction or vacuum distillation.

The heating reaction temperature depends on the melt viscosity of the polyester polycarboxylic acid, but is usually 80 to 230°C, preferably 130 to 200°C. Although the reaction of the present invention proceeds without the use of a catalyst, it is usually
/) Pheno-μ, 2-ethyl-4-methylimidazo-μ
Tertiary amines (or salts thereof) such as triamine! The reaction can proceed more smoothly by using a catalyst such as a quaternary ammonium compound such as ammonium phenolate or an alkali metal alkali metal oxide such as sodium hexanetriolate. The amount of these catalysts used is preferably 0.01 to 1% by weight based on the total weight of the two raw materials. Furthermore, if necessary, there is no problem in carrying out the reaction in a solvent such as methionine, ethyl glycol acetate, or glutyl acetate. In this case, the bath agent may be concentrated and removed after the reaction, or may be precipitated in a non-solvent.

The reaction time depends on whether a catalyst is added or not, but it is usually 1.
Chills in 0 minutes to 5 hours. The reaction product obtained by the method of the present invention has 1 to each of at least two or more carboxy μ groups of the μ poxy μ groups of the polyester polycarboxylic acid.
Mol of diepoxide is added.

The polyester resin having at least two or more epoxy groups at the end, which is thus produced by the method of the present invention, has an epoxy equivalent of 300 to 5,000, is solid, does not cause powder blocking, and is powder free. It is extremely useful as a component of paint compositions. The coating film obtained by curing the epoxy group-containing polyester resin component of the present invention has excellent light resistance and does not have surface defects such as roughness on the appearance of the coating surface. Further, by selecting an alicyclic or aliphatic component as the acid or alcohol component of the polyester polycarboxylic acid, a resin with even better weather resistance can be obtained.

Next, an example in which the resin component obtained by the method of the present invention is used as a powder composition will be described.

The resin component of the present invention can be cured using a curing agent capable of curing ordinary epoxy resins, and is used as a composition in combination with such a curing agent. Examples of curing agents include diaminodiphenylmethane, dianediamide, and dihydrazisuccinate. Amine-based compounds such as dihydrophthalic anhydride, sebacic acid dihydrofuide, and diaminomaleonitrile; acid anhydrides such as tetrahydrophthalic anhydride, methyl-tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic anhydride, and trimellitic anhydride; Or for example sebacic acid, decanedicarboxylic acid,
These include dibasic acids such as octadecanedicarboxylic acid.

Epoquine polymerization catalysts such as various amine complexes such as boron fluoride or various imidazo-7 compounds can also be used.

When preparing a powder composition, the blending ratio of the polyester resin having an epoxy group at the terminal and the curing agent is such that when the curing agent is an amine compound, the number of epoxy groups is 0. If the curing agent is an acid anhydride, the curing agent is a carboxyl group-containing compound so that the number of epoxy groups is 0.3 to 3.0 to the number of acid anhydride groups. In this case, the number of epoxy groups relative to the number of carboxyne μ groups is preferably 0.3 to 3.0.

Such powder compositions may contain catalysts/fillers, leveling agents, antifoaming agents, and surfactants as required.

Antiblocking agents, antioxidants, pigments, dyes, etc. can be added.

The powder composition can be prepared using a method known per se. For example, a curing agent is added to a solid polyester resin having an epoxy group, and various additives are further added as necessary, and then these are melt-kneaded in an extrusion mixer. A powder composition can be obtained by pulverizing the obtained kneaded material with a pulverizer or freeze-pulverizing it.

Alternatively, the mixture may be mixed with a heating roll and then pulverized. moreover,
After dissolving or dispersing each component in a solvent and mixing,
It may be pulverized by spray drying or freeze drying, or it may be pulverized after removing the solvent under reduced pressure and heating. Furthermore, each component can be powdered and mixed to form a powdered composition. The particle size of the powder after pulverization is usually 5 to 500.
Micron ones are used.

The obtained powder composition is useful as a paint or adhesive composition, and a method known per se can be used to apply it to the surface of an object to be coated or an adherend. For example, the coating can be performed using an electrostatic powder coating machine, an electric field curtain type powder coating machine, a hot-medium applicator, or the like. Further, a coating film can also be formed using a fluidized dipping method or a thermal spraying method.

After coating, a cured film is formed by heating in a heating furnace. Baking hardening temperature conditions depend on the presence or absence of a catalyst, but
Usually the temperature of the object to be coated is 100-220℃, the time is 10-12
It takes about 0 minutes. Furthermore, when baking at a high temperature, the baking time can be shortened. The composition containing the epoxy group-containing polyester resin component of the present invention can be applied to coating or bonding various materials such as metal, glass, concrete, ceramics, and roof tiles.

A cured coating film made from such a composition has - excellent weather resistance, adhesion, chemical resistance, water resistance, anti-chip paint for moving vehicles, coating for guardrails, outdoor play equipment, fences, etc., corrosion protection for iron pipes, etc. It is particularly suitable as a layered resin lining or a rust-preventing coating for steel frames, as well as a sealing agent, a fixing agent, and an impregnating agent for electrical parts.

The present invention will be specifically described below with reference to Examples and Reference Examples.

Example ■ Polyester polycarboxylic acid (acid value 86.0, molecular weight 1300, m,
P, 110-115℃) 652g was kept at 185℃, and 140g of vinyl cyclohexene dioxide was added to it.
After adding 0.4 f of benzyldimethylamine, the mixture was reacted at 190°C. Table IK shows the reaction time and the properties of the obtained polyester μ resin having epoxy groups.

The above-mentioned polyester polycarboxylic acid as a raw material and the resin (3) obtained by reaction for 3 hours were analyzed for K by gel permeation chromatography (hereinafter abbreviated as GPC) [Instrument: Shimadzu G, P C-I
A + sample concentration 0.2% (solvent: tetrahydrofuran)]. The results are shown in FIG.

In the figure, A represents the obtained resin and a represents the peak curve of the raw material polyester polycarboxylic acid, but since A is a parallel translation of a, the force per μ phoxyl group is On the other hand, it can be seen that 1 mole of diepoxide was added normally and no high molecular weight resin was produced as a by-product.・ Example ■ ・ 7 mol of neobentyl glycol and 8 m of Tefucric acid
Polyester polycarboxylic acid obtained by reacting with 01 (acid value 63.0. molecular weight /, ?00, m, p
While maintaining 890y at 175°C, vinyl cyclohexene dioxide 140f was added thereto and reacted at 180°C. Table 1 shows the reaction time and the properties of the obtained polyester μ resin having epoxy groups.

Polyester polycarboxylic acid and 3 used as raw materials
The resin (3) obtained by the time reaction was analyzed by GPC. The results are shown in Figure 2. Example■
It can be seen that no high-molecular-weight resin was produced as a by-product, similar to the product.

Comparative Example■ While maintaining the same polyester polycarboxylic acid 652LI as used in Example ■ at 185°C, diglycidylhexahydrofucre) 284F was added thereto, and the temperature was increased to 180°C.
When the reaction was carried out, the mixture started to thicken after 30 minutes, became difficult to stir after 40 minutes, and finally gelled after 50 minutes.

Comparative Example ■ 652 g of the same polyester polycarboxylic acid used in Example I was treated with Epikote 8 while keeping it at 185°C.
28 (Bisphenol A5 epoxy resin manufactured by Shell Co., Ltd., epoxy equivalent: 190) was added thereto at 380 μm and reacted at 165°C. Table 1 shows the reaction time and the properties of the obtained resin. Further, each of the raw material polyester μ polycarboxylic acid, resin (1) obtained by reacting for 1 hour, and resin (3) obtained by reacting for 3 hours was analyzed by GPC. The results are shown in Figure 3. a is raw material, B is resin (1)
, B' indicate the respective peak curves of resin (3).

In the curves shown by B and B', compared to the curve shown by a, the tail on the right side of the peak has expanded, indicating that high molecular weight resin is produced as a by-product, and the appearance of a new peak indicates that unreacted It can be seen that the raw material epoxy strength remains in the composition.

Table 1 Reaction time and properties of the obtained resin Example ■ Neopentyl glyco-/I/7 mol, terephthalic anhydride 4 mol, and hexahydrophthalic anhydride 4 mol
Polyester polycarboxylic acid obtained by reacting (acid value 62.4, molecular weight 1800, m, p, 90-95
'C) 900fI was kept at 1aoHc, and vinyl cyclohexene dioxide 1409 was added to it, and 18
The reaction was carried out at 5°C for 1 hour to obtain a solid polyester resin having epoxy groups (m, p 90 to 95°C, acid value 3.8, epoxy equivalent 1,035).

Reference example ■ Polyester resin having epoxy groups obtained in the example process (3) 840 f and 1 of tetrahydrofucuric anhydride
60y and imidazo-/L/3f were added and melted and mixed, and then ground to obtain a powdery composition. This powder coating composition was electrostatically applied onto an iron plate, and then cured in a baking oven at 190°C for 20 minutes. Table 2 shows the physical properties of the obtained film.

Reference example■ Polyester resin having an epoxy group at the end obtained in the example process (3) Decanedicarboxylic acid 13 to 870 f
0 g and imidazo-/l/3f were added and melted and mixed, and then ground to obtain a powdery composition. This composition was electrostatically coated onto an iron plate and then cured in a baking oven at 190C for 20 minutes.

Table 2 shows the physical properties of the obtained film.

Reference example■ Diaminodiphenylmethane 651 is added to the polyester resin 935y having an epoxy group at the end obtained in the example process!
and imidazo-13f were added and melted and mixed, and then ground to obtain a powdery composition. This composition was electrostatically coated on an iron plate and then baked in a baking oven at 180°C for 20 minutes. Table 2 shows the physical properties of the obtained film.

Reference example ■ Polyester l having an epoxy group at the end obtained in Example ■
'lli fat 870 f to anhydrous tetrahydrophthalate to acid 1
After adding and melting 30f and imidazo-ρ3f,
A powdered composition was obtained by pulverization. This composition was electrostatically coated onto an iron plate and then cured in a baking oven at 190°C for 20 minutes.

Table 2 shows the physical properties of the obtained film.

Table 2

[Brief explanation of the drawing]

FIG. 1 shows a chart obtained by group permeation chromatography analysis of the polyester resin (4) having an epoxy group at the terminal obtained in Example I and the polyester polycarboxylic acid (a) which is a raw material thereof. FIG. 2 shows a chart obtained by glupermeation chromatography analysis of the polyester resin (A) having an epoxy group at the terminal obtained in Example (2) and the polyester polycarboxylic acid (a) which is a raw material thereof. Figure 3 shows a chart obtained by glupermeation chromatography analysis of the products CB and B') obtained in the comparative example and the polyester polycarboxylic acid (a) which is the raw material thereof. $1 mouth +75 150
+25 Shinemi*Lf (m)) Chi 2 Figure 175 150
125 Nne, meeting elephant 2 (m)) 3 Figure 175 150
125 Qi, Elephant Gantry (mZ) Procedural Amendment (Spontaneous) ■, Indication of the Case Patent Application No. 73471 of 1982 2. Name of the invention Process for producing polyester resin having 2 epoxy groups 3. Person making the amendment Relationship to the incident Patent applicant address 2-27 Doshomachi, Higashi-ku, Osaka Name (
293) Take IJJ Pharmaceutical Industry Co., Ltd. Representative Hayashi Kura
Blue 4 Part 4, Agent address: 2-17-85 Jusanhonmachi, Yodogawa-ku, Osaka City, Take III Pharmaceutical Industry Co., Ltd., Osaka Factory 6, Contents of amendment (1) Page 2, line 4, “Light resistance Correct "weather resistance" to "weather resistance." (2) On page 8, line 11, "optical" is corrected to "symptomatic". (3) On page 16, in the second line, "Anhydrous telelifter" is corrected to "Anhydrous lid."that's all

Claims (1)

[Claims] A molecular weight of 400 to 10,000 and an acid value of 10 to 3.
00qKOH/f Two or more force μ Pokin μ at the end
At least two turtles at the terminal, characterized by reacting a polyester polycarboxylic acid having a group with a diepoxide represented by the general formula C, in which R and R' are the same or different hydrogen atoms or lower alkyl. A method for producing a polyester resin having an epoxy group as described above.