JP2876771B2 - Thermosetting composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a novel thermosetting composition, more specifically, a cured product excellent in chemical performance, physical performance, weather resistance, etc., and also has storage stability. The present invention relates to a thermosetting composition suitably used for, for example, paints, inks, adhesives, molded articles, and the like.

[Prior art] A thermosetting composition utilizing an acetal exchange reaction of an acetal alkoxy group or a ketal alkoxy group with a polymer polyol has been known, and for example, a coating composition utilizing this reaction has been disclosed ( U.S. Patent No. 3,
200,099, European Patent Nos. 140,357A2 and 255,608A2).

The thermosetting composition using such an acetal exchange reaction is safe because it does not contain substances harmful to the human body such as isocyanates and aldehydes, and is not discharged, and is a cured product obtained. It has characteristics such as excellent chemical performance and physical performance.

The acetal exchange reaction proceeds in the presence of an acid catalyst, and an acid catalyst is an essential component in a thermosetting composition utilizing this reaction.

However, the reactivity between the polymer polyol and the acetal alkoxy group or the ketal alkoxy group in the presence of the acid catalyst is extremely high, and in a composition in which these three components coexist, gelation occurs during storage or the pot life is short. And other problems.

Therefore, as a means to solve such a problem,
For example, a method has been proposed in which an acid catalyst is neutralized with volatile amines, or a low molecular weight primary monoalcohol is added, and an acetal alkoxy group or a ketal alkoxy group and the acetal equilibrium of the alcohol are used. [Farbe und Lac
k), Vol. 94, No. 6, p. 425 (1988)]. However, although all of these methods are effective in improving storage stability at temperatures around room temperature, they are not always sufficient to improve storage stability at temperatures of 50 ° C or higher assuming outdoor storage in summer. However, there is a problem that a composition which can be used as a one-pack type paint cannot be provided.

[Problems to be Solved by the Invention] The present invention is excellent in safety without containing or discharging harmful substances, gives a cured product excellent in chemical performance and physical performance, and has good storage stability, The purpose of the present invention is to provide a thermosetting composition that can be used as a one-pack type.

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to develop a thermosetting composition having the above-mentioned preferable properties, and as a result, a specific hydroxyl group-containing resin and an acetal alkoxy group in one molecule have been obtained. A compound having at least three groups or ketal alkoxy groups, and a special heat-latent acid catalyst that is thermally dissociated only upon heating and expresses an active acidic group, as its essential components. Find that it is possible to achieve
Based on this finding, the present invention has been completed.

That is, the present invention provides (A) a number average molecular weight of 1,000 to 10
0,000 and a hydroxyl group-containing resin having a hydroxyl value of 50 to 300, (B) 1
In the molecule, the general formula (Wherein R in the formula is an alkyl group having 1 to 6 carbon atoms) a compound having at least three acetal alkoxy groups or ketal alkoxy groups, and (C) a heat-latent acid catalyst having activity during heat curing. Is provided as an essential component.

 Hereinafter, the present invention will be described in detail.

In the composition of the present invention, the hydroxyl group-containing resin used as the component (A) needs to have a number average molecular weight in the range of 1,000 to 100,000 and a hydroxyl value in the range of 50 to 300. When the number average molecular weight is less than 1,000, the water resistance and solvent resistance of the cured product are inferior, and the object of the present invention cannot be sufficiently achieved.When the number average molecular weight exceeds 100,000, the viscosity of the obtained composition becomes too high, and the workability is increased. There is a tendency to worsen. On the other hand, if the hydroxyl value is less than 50, since the number of crosslinking points is small, there is a possibility that a cured product having sufficient hardness may not be obtained,
If it exceeds 0, the viscosity of the resin itself increases,
There is a tendency for solubility in organic solvents to decrease.

The hydroxyl group-containing resin is not particularly limited as long as the number average molecular weight and the hydroxyl value are within the above ranges. Examples of such a resin include a polyester resin, a polyacryl resin, a polyvinyl alcohol resin, an epoxy resin, a phenol resin, a polyurethane resin, and a fluorine resin.

The hydroxyl group-containing resin of the component (A) is, in addition to the hydroxyl group,
If necessary, it may have a functional group such as a carboxyl group, a mercapto group, or an epoxy group as long as storage stability is not reduced. In the composition of the present invention, one kind of the hydroxyl group-containing resin of the component (A) may be used.
A combination of more than one species may be used.

In the composition of the present invention, as a component (B), a molecule represented by the general formula (R has the same meaning as described above). A compound having at least three acetal alkoxy groups or ketal alkoxy groups is used.

When the carbon number of the alkyl group in the acetal alkoxy group or the ketal alkoxy group exceeds 6, the acetal exchange reactivity with the polymer polyol is inferior.
If the amount of the acetal alkoxy group or ketal alkoxy group in the molecule is less than 3, a sufficient crosslinking density cannot be obtained,
The hardness, water resistance, and solvent resistance of the cured product are poor, and the object of the present invention cannot be sufficiently achieved.

As the compound of the component (B), for example, a compound represented by the general formula (R ¹ , R ² , R ³ and R ⁴ in the formula are each an alkyl group having 1 to 6 carbon atoms, which may be the same or different, and Y is a carbon atom. Which is an alkylene group, an arylene group or an alkarylene group of Formulas 2 to 15); (R ⁵ , R ⁶ , R ⁷ and R ⁸ in the formula are each an alkyl group having 1 to 6 carbon atoms, which may be the same or different, and n is 1 Which is an integer of up to 15).

The compound represented by the general formula (II) is produced, for example, by preparing an aliphatic dialdehyde having 2 to 15 carbon atoms or a dialdehyde having one or more aromatic rings from a monohydric alcohol having 1 to 6 carbon atoms. can do. In addition, the general formula (II
The compound represented by I) can be produced, for example, by adding a trialkyl orthoformate to a vinyl ether in the presence of a Lewis acid catalyst (US Pat. No. 2,527,533).

Further, as the component (B), an adduct of a hydroxyl group-containing acetal compound such as 4,4-dimethoxybutan-1-ol and a polyfunctional isocyanate compound, or the low-molecular-weight polyvalent acetal compound and a diol or triol Condensates with the same can also be used.

In the composition of the present invention, the compound of the component (B) is 1
Species may be used, or two or more kinds may be used in combination. It is desirable to select the compounding amount such that the alkoxy group becomes 0.5 to 2.0 equivalent per 1 equivalent of the hydroxyl group of the component (A). .

In the composition of the present invention, the heat-latent acid catalyst used as the component (C) promotes a curing reaction during curing of the composition, imparts good chemical performance and physical performance to the cured product, Is an indispensable component for achieving long-term stability during storage, and a compound exhibiting acid catalytic activity at a temperature of 60 ° C. or higher is desirable. If the heat-latent acid catalyst exhibits an acid catalyst activity at a temperature lower than 60 ° C., the resulting composition thickens or gels during storage,
This may lead to an undesired situation.

As the heat latent acid catalyst of the component (C), sulfonic esters, phosphoric esters and onium compounds are preferably used.

As the sulfonic acid esters, for example, a compound represented by the general formula (In the formula, R ⁹ is a phenyl group, a substituted phenyl group, a naphthyl group, a substituted naphthyl group or an alkyl group, and R ¹⁰ is a C 3-18 carbon atom bonded to a sulfonyloxy group via a primary or secondary carbon. An alkyl group, an alkenyl group, an aryl group, an alkaryl group, an alkanol group, a saturated or unsaturated cycloalkyl or hydroxycycloalkyl group), specifically, methanesulfonic acid, ethanesulfonic acid, benzene Sulfonic acids such as sulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, nonylnaphthalenesulfonic acid, and n-propanol;
Primary alcohols such as n-butanol, n-hexanol and n-octanol or esterified products with secondary alcohols such as isopropanol, 2-butanol, 2-hexanol, 2-octanol and cyclohexanol; Β-hydroxyalkylsulfonic acid esters obtained by reaction with an oxirane group-containing compound, and the like.

As the phosphoric esters, for example, the general formula Wherein R ¹¹ is an alkyl group, cycloalkyl group or aryl group having 3 to 10 carbon atoms, and m is 1 or 2. Specifically, n-propanol, n-
Butanol, n-hexanol, n-octanol, 2
Primary alcohols such as ethylexanol or isopropanol, 2-butanol, 2-hexanol, 2
-Phosphoric acid monoesters and phosphoric acid diesters of secondary alcohols such as octanol and cyclohexanol.

Further, examples of the onium compounds, for example the general formula _{^{[R 12 3 NR 13] +}} X - ... (VI) [R 12 3 PR 13] + X - ... (VII) [R 12 2 OR 13] + X - ... (VIII) and _{^{[R 12 2 SR 13] +}} X - ... (IX) (R 12 represents an alkyl group having 1 to 12 carbon atoms in the formula, alkenyl group, aryl group, alkaryl group, alkanol group or a cycloalkyl group Wherein two R ¹² may be bonded to each other to form a heterocyclic ring having N, P, O or S as a hetero atom, and R ¹³ is a hydrogen atom, a carbon atom having 1 to 12 carbon atoms. alkyl group, an alkenyl group, an aryl group, an alkaryl group, X ^- is _{^{SbF 6 -, AsF 6 -,}} PF 6 - or BF ₄ ^- is a) include compounds represented by like.

In the composition of the present invention, one kind of the heat-latent acid catalyst of the component (C) may be used, or two or more kinds thereof may be used in combination. )) Usually selected in the range of 0.01 to 10 parts by weight per 100 parts by weight of the total solid content with the component.

The temperature and time required for curing the thermosetting composition of the present invention vary depending on the type of the heat-latent acid catalyst to be used, but usually heating at a temperature in the range of 60 to 200 ° C for about 2 minutes to 1 hour. Completes the curing.

The thermosetting composition of the present invention may be used as it is, or as necessary, by blending a coloring pigment, a filler, a solvent, an ultraviolet absorber, an antioxidant, and the like, for use in paints, inks, adhesives, molded articles, and the like. Can be.

[Examples] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Production Examples 1 to 3 Production of hydroxyl group-containing resins A-1 to A-3 4 equipped with a thermometer, a reflux condenser, a dropping funnel, and a stirrer
Each of the synthesis solvents shown in Table 1 was charged into a one-necked flask, and heated and stirred until the solvent was in a reflux state. Next, each of the monomer mixtures shown in Table 1 was dropped into the flask over 2 hours using a dropping funnel while maintaining reflux and stirring. After completion of the dropwise addition, the mixture was refluxed and stirred for 30 minutes. After that, the reaction temperature was lowered to 100 ° C, the additional catalysts shown in Table 1 were added, and the reaction was terminated when the temperature was further maintained at 100 ° C for 2 hours. Then, hydroxyl group-containing resins A-1 to A-3 each having the characteristic values shown in Table 1 were obtained.

Production Examples 4 and 5 Production of Acetal Alkoxy Group-Containing Compounds B-1 and B-2 In a four-necked flask equipped with a thermometer, a Dean-Stark fractionating tube, a reflux condenser, a nitrogen gas introducing tube, and a stirrer, Charge the mixture having the composition shown in Table 2 and introduce nitrogen gas.
The mixture was heated to 130 to 140 ° C. and stirred. The reaction proceeds with the generation of methanol by acetal exchange, and the end point of the reaction is determined by the disappearance of the absorption derived from the hydroxyl group near 3500 cm ^{−1 in the} infrared absorption spectrum and the amount of generated methanol. After the reaction is completed, the product is
Neutralization was performed until the pH value reached 7, thereby obtaining acetal alkoxy group-containing compounds B-1 and B-2 each having the characteristic values shown in Table 2.

Production Examples 6 to 8 Production of Heat Latent Acid Catalysts C-1 to C-3 2 equipped with a thermometer, a cooling pipe, a dropping funnel, and a stirrer
Each of 350 parts by weight of the alcohols shown in Table 3 was placed in a four-necked flask, cooled with ice, 44.9 parts by weight of potassium-t-butoxide was added and dissolved therein, and then dissolved in 300 parts by weight of diethyl ether. 53.4 parts by weight of the sulfonyl chloride shown in Table 3 was added dropwise over 30 minutes. One hour after the addition, the ice bath was removed, and the reaction was further performed for one hour. After the completion of the reaction, the reaction mixture was washed three times with 300 parts by weight of water, and then molecular sieve 4A1 / 16 (manufactured by Wako Pure Chemical Industries, Ltd.) was added thereto, followed by dehydration and drying, and the solvent was distilled off by a rotary evaporator. As a result, heat-latent acid catalysts C-1 to C-3, which are the compounds shown in Table 3, were obtained.

Production Example 9 Production of acetone solution of thermal latent acid catalyst C-4 2 equipped with thermometer, cooling pipe, dropping funnel, and stirrer
In a four-necked flask, put 322 parts by weight of acetone, p-
After adding and dissolving 172 parts by weight of toluenesulfonic acid, 1
Cooled to 0 ° C. 250 parts by weight of Kadura E-10 (epoxy equivalent: 250, manufactured by Shell Chemical Co., Ltd.) dissolved in 100 parts by weight of acetone was added dropwise over 1 hour and 30 minutes so that the internal temperature was between 10 ° C and 15 ° C. . Thereafter, the mixture was stirred at a temperature of about 10 ° C. for 30 minutes, and further stirred at room temperature for 2 hours to obtain a 50 wt% acetone solution of the heat-latent acid catalyst C-4.

Example 1 To 100 parts by weight of the hydroxyl group-containing resin (A-2) obtained in Production Example 2, the acetal alkoxy resin (B-
1) 11.4 parts by weight of the heat-latent acid catalyst (C-
1) 12.5 parts by weight of a solution obtained by diluting 1) with xylene so as to be 10 wt% in terms of p-toluenesulfonic acid;
A part by weight was added and the mixture was stirred until it became uniform to obtain a clear solution. Next, using a thinner (xylene / methyl isobutyl ketone = 9/1 weight ratio), paint viscosity (Ford Cup No. 4, 20)
(22 ° C at 22 ° C), then dry thickness 30μm on a tin plate
And spray-cured at 140 ° C. for 30 minutes.

The obtained cured film has a Knoop hardness of 11.4 according to the method described in ASTM-1474, and no dissolution or softening of the film is observed even when the cured film is rubbed with a xylene-immersed flannel. It showed sufficient curability under the conditions.

On the other hand, the clear solution before dilution with thinner is
Showed good storage stability without gelling even after storage for one week.

Examples 2 to 11 Based on the formulations shown in Table 4, clear solutions were prepared in the same manner as in Example 1. Next, after coating in the same manner as in Example 1, it was cured under the curing conditions shown in Table 4. Each of the cured films thus obtained was tested for curability and storage stability in the same manner as in Example 1. Table 4 shows the results.

In all the examples, sufficient curability and good storage stability were confirmed.

Comparative Example 1 Based on the formulation shown in Table 4, a clear solution and a cured film were prepared by the same operation as in Example 1, and the same performance evaluation as in Example 1 was performed. It was found that in this example which did not contain the composition, the composition did not cure under the curing conditions of 140 ° C. and 30 minutes.

Comparative Example 2 Based on the formulation shown in Table 4, a clear solution and a cured film were prepared in the same manner as in Example 1, and the same performance evaluation as in Example 1 was performed. In this example where the acid catalyst is included in the formulation
Although cured under the curing conditions of 140 ° C for 30 minutes, it is gelled after one day of the stability test at 50 ° C because it is not a heat-latent acid catalyst in which the hydrogen of the p-toluenesulfonic acid group is blocked. It turned out not to show sex.

[Effect of the Invention] The thermosetting composition of the present invention is excellent in chemical performance, physical performance, weather resistance, and the like, and also excellent in storage stability.
It is suitably used for a wide variety of paints, inks, adhesives, plastic molded products, and the like.

Continuation of the front page (51) Int.Cl. ⁶ identification code FI C08K 5: 521 5:17 5:50) (58) Field surveyed (Int.Cl. ⁶ , DB name) C08L 1/00-101/14 C09D 101/00-201/10 C09J 101/00-201/10

Claims (2)

(57) [Claims] (A) a hydroxyl group-containing resin having a number average molecular weight of 1,000 to 100,000 and a hydroxyl value of 50 to 300, (B) one molecule,
General formula (Wherein R in the formula is an alkyl group having 1 to 6 carbon atoms) a compound having at least three acetal alkoxy groups or ketal alkoxy groups, and (C) a heat-latent acid catalyst having activity during heat curing. A thermosetting composition comprising as an essential component. 2. The thermosetting composition according to claim 1, wherein the component (C) is at least one selected from sulfonic esters, phosphoric esters and onium compounds.