JPH04253722A - Production of acid-modified resin and resin composition - Google Patents

Abstract

PURPOSE:To obtain an acid-modified resin excellent in low-temperature driability. CONSTITUTION:A bisphenol diglycidyl ether epoxy resin and N- methylmonoethanolamine are subjected to an addition reaction, and the adduct is reacted with a dehydrated castor oil fatty acid to obtain an acid-modified resin. This resin can give a film having sufficient properties when dried at 60 deg.C for 20min.

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 acid-modified resins and a resin composition.

0002

BACKGROUND OF THE INVENTION JP-A-59-38261 describes a modified resin having a structure in which an amino alcohol is added to an epoxy compound.

0003

[Problems to be Solved by the Invention] However, the modified epoxy resin described in the above-mentioned Japanese Patent Application Laid-Open No. 59-38261 can produce a coating film with excellent corrosion resistance if baked at 100°C or higher, but it cannot be used at low temperatures. When baked, it had the disadvantage of being inferior in low-temperature drying properties not only when compared with known epoxy resins but also when compared with conventional amine-modified epoxy resins.

0004

[Means for Solving the Problems] The inventors of the present invention made extensive studies in view of the above circumstances and found that a modified resin having a structure in which amino alcohols are added to an epoxy compound has a structure in which the hydroxyl group and monocarboxylic acid are ester bonded. It was discovered that the acid-modified resin has excellent low-temperature drying properties, and the present invention was completed. That is, the present invention provides a method for producing an acid-modified resin, which is characterized by reacting a hydroxyl group of a modified epoxy resin (A) with a structure in which an amino alcohol is added to an epoxy compound and a monocarboxylic acid (B), and an epoxy resin. In the resin composition consisting of a modified product and a curing agent, the epoxy resin has an ester bond between the hydroxyl group of the modified epoxy resin (A) and the monocarboxylic acid (B), which has a structure in which an amino alcohol is added to the epoxy compound. The present invention provides an epoxy resin composition characterized by being an acid-modified resin (C) having the following structure.

The modified epoxy resin (A) according to the present invention refers to a modified resin having a structure in which an amino alcohol is added to an epoxy compound, and it is sufficient that it has such a structure.
The manufacturing method itself is not particularly limited. It is usually produced by adding amino alcohols to epoxy compounds.

The epoxy compound used in this case is not particularly limited, but for example, bisphenol A diglycidyl ether type epoxy resin, bisphenol F
Bisphenol diglycidyl ether type epoxy resin such as diglycidyl ether type epoxy resin, phenol novolac type epoxy resin, cresol novolak type epoxy resin, di(diglycidyloxy)aminoethylene,
Examples include glycidyl amines such as di(diglycidyloxy)aminodiphenylmethane.

The most typical epoxy compound is a commercially available epoxy resin obtained from bisphenol A and epichlorohydrin. The epoxy compound preferably has an epoxy equivalent of 450 to 10,000, particularly a number average molecular weight (Mn) of 600 to 25,000.
It is more preferable that

Next, the above-mentioned amino alcohols refer to those having one amino group and at least one hydroxyl group in the molecule. Any known and commonly used amino alcohols can be used, such as monoethanolamine,
Examples include diethanolamine, N-methyl-monoethanolamine, diisopropanolamine, and aminodibenzyl alcohol.

The modified epoxy resin (A) according to the present invention can be produced by, for example, reacting the epoxy group in the above-mentioned epoxy compound with the amino group of an amino alcohol to introduce a hydroxyl group at or near the end of the molecule. can be obtained easily.

The conditions for producing the modified epoxy resin (A) are not particularly limited, and the desired product can be obtained even if the reaction is carried out gently at room temperature in the absence of a catalyst. 0.5 to 2.0 of the amino group to
These two compounds are preferably mixed at a ratio of 0.8 to 1.5 chemical equivalents, and heated to 50 to 250°C, preferably 8
It can be obtained more easily by heating at 0 to 200°C in the presence or absence of a solvent.

Next, the acid-modified resin of the present invention can be obtained by reacting the modified epoxy resin (A) with a monocarboxylic acid (B). As the monocarboxylic acid (B) that can be used in this case, any compound having one carboxyl group in the molecule can be used. Examples of monocarboxylic acids (B) include saturated aliphatic monocarboxylic acids such as stearic acid, castor oil fatty acids, soybean oil fatty acids,
Examples include unsaturated fatty acids such as safflower oil fatty acids, dehydrated castor oil fatty acids, and linseed oil fatty acids.

This monocarboxylic acid (B) reacts with the hydroxyl group in the above-mentioned modified epoxy resin (A) to introduce an aliphatic chain at the end of the molecule or into the molecular chain via an ester bond. It is.

[0013] The above-mentioned epoxy resin modified product (A)
and monocarboxylic acid (B) to form an acid-modified resin (
The conditions for obtaining C) are not particularly limited, and the modified epoxy resin (A) and monocarboxylic acid (B) may be reacted in any weight ratio.

[0014] In this case, in the presence of a catalyst, 15
Any acid-modified resin (C) can be obtained by heating to 0°C to 260°C, preferably 180°C to 240°C.

[0015] Examples of the catalyst that may be used as necessary include dibutyltin dilaurate, tetraisopropyl titanate, cobalt naphthenate, and zirconium octenoate.

The acid-modified resin (C) of the present invention can be used as it is, but it is often used after being made into a varnish using a solvent. Examples of the solvent used as necessary include toluene, xylene, acetone, methanol, butanol, methyl ethyl ketone, methyl isobutyl ketone, cellosolve acetate, butyl cellosolve, and the like.

The acid-modified resin (C) of the present invention may further contain fillers, plasticizers, surfactants, thickeners, colorants, flame retardants, water and oil repellents, and silane coupling agents, if necessary. or synthetic resins such as acrylic resin, polyester resin, polyether resin, polyurethane resin, phenol resin, urea resin, polyamide resin, alkyd resin, silicone resin, vinyl chloride resin, vinyl acetate resin, etc. It's okay.

The acid-modified resin (C) of the present invention has drying properties as it is at any temperature and is easily formed into a coating film. In particular, it has excellent drying properties at 15°C to 100°C. Drying can be carried out arbitrarily, but drying may be performed by applying hot air, by irradiating with infrared rays, or by natural drying. When a silane coupling agent is used as an additive, irradiation with infrared rays tends to improve adhesion to the base material.

The acid-modified resin (C) using an unsaturated fatty acid as the monocarboxylic acid (B) can be further improved in low-temperature drying properties by adding metal soaps, and a coating film with excellent water resistance can be obtained.

By adding an aluminum drying agent to the acid-modified resin (C) of the present invention, low-temperature drying properties are further improved, and a coating film with excellent adhesion can be obtained. The acid-modified resin (C) of the present invention has excellent drying properties at low temperatures of 100°C or less in its varnished form or in the form of further additives, and is used, for example, in automobile parts, industrial machinery, agricultural machinery, etc. Ideal for painting and interior painting, the so-called aftercoat industry.

A curing agent can also be added to the acid-modified resin (C) of the present invention. Examples of curing agents that can be used in this case include aminoplast resin, phenoplast resin,
Examples include polyisocyanate and blocked polyisocyanate. The amount of curing agent used is not particularly limited, but
Usually 3 to 100 parts by weight of solid content of acid-modified resin (C)
It is 80 parts by weight. The cured product of the composition using the acid-modified resin (C) and curing agent of the present invention is the resin (C) before being acid-modified.
It has an effect of being superior in flexibility compared to a cured product of a composition using a curing agent.

[0022] A product containing a short oil type acid-modified resin (C) and a curing agent blended with the acid-modified resin (C) is heated at 100°C.
When dried at ~250°C without or in the presence of a catalyst, a cured coating film with excellent solvent resistance, corrosion resistance, chemical resistance, and processability can be obtained, and it has excellent performance as a paint raw material for general industrial use or the precoat industry. It is something that you have.

The substrate to which the acid-modified resin (C) of the present invention is coated is not particularly limited, but includes, for example, metal, wood, plastic, stone, slate, concrete, mortar, fiber, paper, ceramics, porcelain, glass, Examples include rubber.

[0024] Examples of the coating method include brush coating,
Spray coating, dip coating, impregnation coating, roll coating,
Examples include methods such as blade coating, flow coating, spin coating, electrostatic coating, and electrodeposition coating.

The acid-modified resin (C) of the present invention can be used, for example, in bodies and parts of automobiles, ships, aircraft, etc., roofs of houses, entrances, gates, sashes, balconies, lockers, desks, audio panels, sinks, gas ranges, refrigerator, washing machine,
In addition to coating materials for bathtubs, floors, etc., resins for prepregs, adhesives,
It can also be used as a sealant.

[0026]

[Examples] Next, the present invention will be specifically explained using reference examples, working examples, and comparative examples. Hereinafter, unless otherwise specified, "part" means "part by weight" and "%" means "% by weight."

Reference Example 1 Commercially available EPICLON4055 obtained from bisphenol A and epichlorohydrin (epoxy resin manufactured by Dainippon Ink and Chemicals Co., Ltd., epoxy equivalent = 910, Mn
= 2100), 7 parts of N-methyl-monoethanolamine, and 52 parts of Solvesso 150 were mixed into 15
After heating and reacting at 0°C for 7 hours, 81 parts of dehydrated castor oil fatty acid and 0.5 part of zirconium octate were added, and the mixture was reacted at 220°C for 6 hours, and 230 parts of xylene and 141 parts of cellosolve acetate were added. An acid-modified resin having a nonvolatile content (hereinafter abbreviated as NV) of 40% and a viscosity (Gardner method at 25° C., hereinafter the same) of N was obtained. Hereinafter, this will be abbreviated as resin (A-1).

Reference Examples 2 to 3 Reference Example 1 except that the formulation was changed as shown in Table 1.
In the same manner as above, resins with property values as shown in the table (
A-2) to (A-3) were obtained.

[0029]

[Table 1]

Example 1 A compound having the following formulation was kneaded using a high-speed dispersion machine,
A new metallization composition was obtained having a PWC of 60% and a viscosity (Ford cup) of 30 seconds.

Resin (A-1) 100 parts Titanium white 30 parts
calcium carbonate
20 parts Talc 40 parts
xylene
80 parts cellosolve acetate
50 parts 1-butanol 50 parts Hereinafter, this will be abbreviated as composition (C-1). Next, a coating film was obtained using this composition (C-1) under the following coating conditions. Table 4 shows where various performance tests were conducted on this coating film.

■Painted board JIS SPCC-SB
44 ■Coating system 1 coat 1 bake ■Film thickness 30μ ■Drying conditions 15 minutes at 80°C Examples 2 to 9 Acid-modified epoxy resins as shown in Table 2 (
A) was changed to use additive or curing agent component (
Various compositions of the present invention (C-2) to (C-9) were obtained in the same manner as in Example 1 except that B) was used.

[0033]

[Table 2]

[0034] Thereafter, coatings were obtained in the same manner as in Example 1 except that each of these compositions was used, and then coating films were obtained from each coating material, and various performance tests were conducted on each coating film. They are summarized in Tables 4 and 5. However, the drying conditions for (C-3) to (C-7) using a curing agent in the composition are 3.
It is 0 minutes.

Comparative Examples 1 to 4 Base resin components (A') as shown in Table 3, respectively
A coating material was prepared in the same manner as in Example 1, except that the additive or curing agent component (B') was used.

[0036]

[Table 3]

[0037] Next, coating films were obtained from each of the above paints, and various performance tests were then conducted on each coating film, as shown in Tables 4 and 5.

[0038]

[Table 4]

[0039]

[Table 5]

Example 1 and Comparative Example 1, Example 2 and Comparative Example 2
As can be seen, the acid-modified resin of the present invention has better secondary physical properties and salt spray test results (
These are measures of low temperature drying. ) is clearly superior, and as can be seen from Example 7 and Comparative Example 3, and Example 8 and Comparative Example 3, the film of the composition of the present invention using a curing agent is superior to that before acid modification. It is clear that the impact test results for secondary physical properties (which are a measure of flexibility) are superior to films of conventional compositions using resins.

[0041]

[Effects of the Invention] Since the resin obtained by the production method of the present invention has been acid-modified, it has a particularly remarkable effect of being superior in low-temperature drying properties compared to conventional non-acid-modified resins.

On the other hand, since the composition of the present invention uses an acid-modified resin, it also has the effect of providing a cured film with superior flexibility compared to the use of conventional non-acid-modified resins.

Claims (5)

[Claims] 1. A method for producing an acid-modified resin, which comprises reacting a hydroxyl group of a modified epoxy resin (A) with a structure in which an amino alcohol is added to an epoxy compound with a monocarboxylic acid (B). 2. The production method according to claim 1, wherein the modified epoxy resin (A) is a product obtained by addition-reacting an epoxy compound and an amino alcohol. 3. The production method according to claim 1 or 2, wherein the monocarboxylic acid (B) is a fatty acid. 4. In a resin composition comprising a modified epoxy resin and a curing agent, the modified epoxy resin contains a hydroxyl group and a monocarboxylic acid ( An epoxy resin composition characterized in that B) is an acid-modified resin having an ester bond. 5. The composition according to claim 4, wherein the curing agent is a phenoplast resin, an aminoplast resin, and a blocked polyisocyanate.