JPH02238016A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition having excellent adhesivity to substrate, heat-resistance, water-resistance, curability, hot-water resistance of adhesivity, etc., and suitable as coating material, binder, adhesive, etc., by using a polyisocyanate and an epoxy resin having terminals modified with bisphenols as essential components. CONSTITUTION:The objective composition contains (A) a polyisocyanate (preferably hexamethylene diisocyanate, its polymer, tolylene diisocyanate and its polymer) and (B) a modified epoxy resin having terminals modified with bisphenols (preferably having a number-average molecular weight of 500-5,000).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel resin composition containing an epoxy resin and a polyisocyanate as curing components, and more specifically, to a novel resin composition containing an epoxy resin and a polyisocyanate as curing components. , resin compositions that have excellent curability, especially hot water adhesion, and are suitable for use in paints for metals, plastics, concrete, etc., binders for magnetic powder, ferrite, adhesives, etc., or as casting materials. It is.

Conventional technology Conventionally, resin compositions containing epoxy resins and polyisocyanates have both the excellent hardening properties of epoxy resins and the flexibility of polyisocyanates. It is useful as an agent or casting material.

As such a resin composition, for example, a composition comprising an alkanolamine-modified epoxy resin and a polyisocyanate is known ["New Epoxy Resin", p. 590, published by Shokodo (1985)]. However, this composition has (1) a tertiary amine in the alkanolamine-modified epoxy resin, which causes a large increase in viscosity and a short pot life of usually 40 minutes or less at a temperature of 25°C;
) When comparing the performance of the cured product with that of the cured epoxy resin product, it has drawbacks such as inferior hot water resistance and adhesion.

Therefore, in order to improve such drawbacks, attempts have been made to use modified epoxy resins modified with monohydric phenols in place of the alkanolamine-modified epoxy resins.

However, in this case, although the hot water resistance is improved, the curability is still significantly reduced, which is not practical.

Furthermore, a composition comprising a combination of a modified epoxy resin having at least 40 mol % of glycol terminals and a polyisocyanate has been proposed (Japanese Patent Laid-Open Publication No. 3900/1983). However, in this composition, although low-temperature curability is achieved by the reaction between the primary hydroxyl group and the isocyanate group in the glycol, the viscosity increases significantly, which poses a problem for practical use.

Problems to be Solved by the Invention The present invention overcomes the drawbacks of conventional resin compositions containing epoxy resin and polyisocyanate as curing components, and improves adhesion to substrates, heat resistance, This was done with the aim of providing a resin composition with excellent water resistance, curability, and especially hot water adhesion.

Means for Solving the Problems As a result of intensive research to improve the physical properties of a resin composition containing an epoxy resin and a polyisocyanate as curing components, the inventor has developed an epoxy resin whose terminal end is modified with bisphenols. The inventors discovered that the objective could be achieved by using a modified epoxy resin, and based on this knowledge, the present invention was completed.

That is, the present invention comprises (A) polyisocyanate, (
B) A resin composition comprising a modified epoxy resin whose terminal end is modified with bis-7 enols.

The present invention will be explained in detail below.

In the composition of the present invention, as the polyisocyanate used as component (A), aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, etc. having two or more incyanate groups in one molecule are used. be able to. Examples of aliphatic polyisocyanates include diisocyanates such as tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, tetramethylhexamethylene diisocyanate, and lysine diisocyanate, and polymers thereof.

Further, examples of the alicyclic polyisocyanate include diisocyanates such as isophorone diisocyanate and cyclohexane-1,4-diisocyanate, and polymers thereof. On the other hand, examples of aromatic polyisocyanates include diisocyanates such as tolylene diisocyanate and methylene diphenyl diisocyanate, and polymers thereof. Note that the multimers mentioned here include diisocyanates, alcohols, acids,
It is a reaction product with an adducting agent such as water.

Among these polyisocyanates, aliphatic polyisocyanates and aromatic polyisocyanates are preferred,
Particularly suitable are hexamethylene diisocyanate and its polymers, and tolylene diisocyanate and its polymers. One type of polyisocyanate as component (A) may be used, or two or more types may be used in combination.

In the composition of the present invention, the modified epoxy resin whose end is modified with bisphenols and used as component (B) is:
The terminal epoxy group of an epoxy resin is modified with bisphenols, and the bisphenols used for modification include, for example, bis7enol A, bisphenol F1, bisphenol AD, bisphenol S1, tetramethylbisphenol A1, and tetramethylbisphenol F.
Among them, bisphenol A is preferred.

In addition, the epoxy resin used has 2
Examples include those having 1 or more epoxy groups, such as glycidyl ethers, glycidyl esters, and glycidyl amines. Examples of the glycidyl ethers include diglycidyl ether of bisphenol, polyglycidyl ether of phenol novolak, diglycidyl ether of alkylene glycol or polyalkylene glycol, and the like. Examples of the diglycidyl ether of bisphenol include dihydric phenols such as bisphenol A1 bisphenol F1 bisphenol AD, bisphenol S1 tetramethylbisphenol A1 tetramethylbisphenol F1 tetramethylbisphenol AD, and tetramethylbisphenol S1 tetramethylbisphenol A1 tetrapromobisphenol A. Examples of diglycidyl ethers of phenol nopolacs include diglycidyl ethers of novolac resins such as phenol nopolac, cresol nopolac, and brominated phenol nopolac, and diglycidyl ethers of alkylene glycols or polyalkylene glycols. Examples of the ether include diglycidyl ethers of glycols such as polyethylene glycol, polypropylene glycol, and butanediol.

Further, examples of the glycidyl esters include diglycidyl esters of hexahydrophthalic acid and diglycidyl esters of dimer acid, and examples of the glycidyl amines include, for example, tetraglycidyl diamino di-7
Enylmethane, triglycidylaminophenol, triglycidyl isocyanurate, and the like.

Epoxy resins used for modification are not limited to these compounds, but among these, preferred are glycidyl ethers and glycidyl amines, more preferred are diglycidyl ethers of bisphenol, and among these, bisphenol A is particularly preferred. diglycidyl ethers are preferred.

The method for producing the modified epoxy resin includes, for example, combining an epoxy resin and bisphenols in the presence of a catalyst such as an alkali metal hydroxide, a tertiary amine, a quaternary ammonium salt, an imidazole, a phosphine, or a phosphonium salt. , usually at a temperature in the range of 80 to 200°C, from 1 to 3
A method of reacting for about 0 hours is used.

At this time, the epoxy resin and bisphenols must be used in such a ratio that the molar ratio of the hydroxyl group of the bisphenol to the terminal epoxy group of the epoxy resin is 1 or more. Further, the number average molecular weight of this modified epoxy resin is usually 500 to 5000, preferably 800 to 400.
Selected within the range of 0. If the molecular weight is less than 500, for example, the flexibility of the coating film will be insufficient, and if it exceeds 5,000, the adhesion of the coating film will be significantly reduced, making it impossible to put it into practical use.

In the composition of the present invention, the polyisocyanate as the component (A) and the modified epoxy resin as the component (B) have a molar ratio of incyanate groups in the component (A) to hydroxyl groups in the component (B) of usually 0. 6-1.4, preferably 0.8-1.
It is used in a ratio of 2. This molar ratio is 0.6
If it is less than 1.4, the water resistance of the cured product will not be sufficient, and if it exceeds 1.4, the thermal stability of the cured product will decrease.

Fillers, reinforcing materials, pigments, etc. can be added to the composition of the present invention as desired.

Examples of fillers include alumina, calcium carbonate,
Silica, calcined silica, glass powder, mica powder, carbon black, graphite, aluminum powder, iron powder, water-containing alumina, asbestos, polyethylene powder, polypropylene powder, mica, kaolin, alumina oxide, bentone, silica aerosol, lithopone, magnetic powder, Examples of reinforcing materials include glass fiber, asbestos fiber, boron fiber, carbon fiber, etc. Examples of pigments include red iron oxide, cadmium yellow, chrome yellow, chromium oxide, cobalt blue, titanium oxide, and cobalt black. It will be done. Furthermore, examples of other additives include coal tar, liquid rubber, silicone resin, and waxes.

Effects of the Invention In the resin composition of the present invention, since the modified epoxy resin of the component (B) has a phenolic hydroxyl group at the molecular end, the The modified epoxy resin has improved curability and hot water adhesion, and since the modified epoxy resin does not have a tertiary amino group or glycol end in the molecule, the stability of the composition is also improved. .

The resin composition of the present invention has excellent adhesion to substrates, heat resistance, water resistance, curability, especially hot water resistance, and is suitable for use in paints for metals, plastics, concrete, magnetic powder, ferrite, etc. Suitable for use as binders, adhesives, casting materials, etc.

Examples Next, the present invention will be explained in more detail with reference to examples.
The present invention is not limited in any way by these examples.

The adhesion and bendability of the coating film were evaluated according to the following methods.

(1) Adhesion Normal state and boiling water adhesion were determined according to the cross-cut test of JIS K 5400. Boiling water adhesion is the coating film at 100°C.
After soaking in water for 1 hour, the temperature was returned to room temperature, and a cross-cut test was performed. The numerical value indicates the remaining number of rows.

(2) Bending property It was determined based on the bending test of JIS K 5400.

Reference Example 1 AER331 (manufactured by Asahi Kasei Kogyo Co., Ltd., bisphenol A type epoxy resin, molecular weight 380, epoxy equivalent 189) and bisphenol A in the amounts shown in Table 1 were charged into a reactor at room temperature, and heated to 60°C while stirring. After warming,
Add a sodium hydroxide aqueous solution having a concentration of 10% by weight to this.
The amount shown in the table was added, and then the internal temperature was gradually raised to 140°C to start polymerization. When the viscosity of the contents increases, the internal temperature is further gradually raised to 170°C, and when the viscosity of the contents becomes constant, the contents are taken out and quickly cooled to room temperature. A modified epoxy resin was obtained. The number average molecular weights are shown in Table 1.

The number average molecular weight of the obtained modified epoxy resin is c
PC C power ram is Shodex 804, 803, 8
02, 802 (using four parallel products).

Reference Example 2 in Table 2 A modified epoxy resin whose terminal end was modified with bis-7 enols was produced in the same manner as in Reference Example 1 using the types and amounts of raw materials shown in Table 2. The results are shown in Table 2.

Table Examples 1 to 6 After preparing paints with the compounding ratios shown in Table 3, they were applied to a mild steel plate so that the cured film thickness was 60 μm, and then heated at 60°C for 2 hours and at IOO°C for 1 hour. A coating film was obtained by curing under the following conditions. The evaluation results of the coating film properties are shown in Table 3.

Table 4 also shows the pot life of each paint at 25°C. Note that the pot life is the time until the paint 1009 stops flowing.

Table 1 Examples 7 to 9 Paints were prepared in the proportions shown in Table 5, and the coating film performance was evaluated in the same manner as in Example 1. The results are shown in Table 5.

Reference Example 3 A modified epoxy resin whose terminal was modified with bisphenol A was produced in the same manner as in Reference Example 1 using the types and amounts of raw materials shown in Table 6. The results are shown in Table 6.

Table 6 Table 6 Comparative Examples 1 and 2 Paints were prepared with the blending ratios shown in Table 7, and the coating film performance was evaluated in the same manner as in Example 1. The results are shown in Table 7.

Comparative Example 3 Example 5 disclosed in JP-A-54-3900
According to α-glycol group 1.6 (equivalent value/10009)
of resin was produced. The pot life of the blend of this resin and hexamethylene diisocyanate was measured in the same manner as in Example 1, and was found to be 35 minutes.

Note that the amount of hexamethylene diisocyanate added was equivalent as in Example 1.

Claims (1)

[Scope of Claims] 1. A resin composition comprising (A) a polyisocyanate and (B) a modified epoxy resin whose terminals are modified with bisphenols. 2 Modified epoxy resin has a number average molecular weight of 500 to 5000
2. The resin composition according to claim 1.