JPS61183350A - Thermosetting resin composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. in which components are well compatible with each other and which gives a coating film having excellent properties and can be cured at low temp./containing a butyl-etherified melamine/ formaldhyde resin and a fluororesin and/or modified fluororesin. CONSTITUTION:1mol of melamine is dissolved in 4-7mol of butanol. While adding dropwise 3-7mol of HCHO, they are subjected to an addition an butyl- etherification reaction in the presence of an acidic catalyst at 90-100 deg.C to obtain a butyl-etherified melamine/formaldehyde resin (A) having a number- average MW of 1,700 or below and contg. 3-5 bonded HCHO molecules and 0.5-2 methylol groups per one melamine nucleus. A fluororesin (B) having a MW of 1000-200,000 and an OH value of 10-100 and contg. OH and alkoxy or cyclohexyl groups and/or a modified fluororesin (B) obtd. by polymerizing 99.5-50wt% ethylenically unsaturated monomer in the presence of a fluororesin contgh.0-0.055mol of reactive C=C bonds per 100g of resin and alkoxy or cyclogexyl group are/is blended with component A.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a thermosetting resin composition comprising a butyl etherified melamine/formaldehyde resin and a fluorine-containing resin or a modified fluorine-containing resin, an aldehyde resin and a fluorine-containing resin. Alternatively, thermosetting resin compositions made by combining modified fluorine-containing resins are used in paints and the like.

JP-A-59-51953 examines various physical properties of a combination of melamine resin and grafted fluorine-containing resin (modified fluorine-containing resin) when baked at 140° C. for 20 minutes. However, in the paint industry, etc., labor-saving and
From the point of view of saving resources and energy, mold coatings are desired for low-temperature curing and baking.

2 at 140-150°C in conventional thermosetting resin compositions.
Baking for 0 to 30 minutes is the lower limit that maintains the functionality of practical properties.

(Problems to be Solved by the Invention) However, in this case, the commonly used butylethylated melamine formaldehyde resin has a relatively large number average molecular weight and contains a relatively large amount of bound formaldehyde and butyl ether groups. It is a mixture of one to several dozen melamine nuclei in two molecules of oak.

-Those having many melamine nuclei in their molecules have relatively high reactivity, but have poor compatibility with fluorine-containing resins or modified fluorine-containing resins. On the other hand, it is known that those with few melamine nuclei in two molecules have many butyl ether groups, tend to have good compatibility, but have low two-reactivity.

The present invention solves these problems.

(Means for solving the problems) The present invention provides (A) a number average molecular weight of 1φOO or less;
Butyl etherified melamine/formaldehyde resin having 3 to 5 bound formaldehydes and 0.5 to 2 methylol groups per melamine nucleus, and (B) a fluorine-containing resin having a hydroxyl group and an alkoxy group or a cyclohexyl group (b- 1) and/or reactive carbon-carbon double bonds at a concentration of 90 to 0 per 100 g of resin.
．． 055 mol and a modified fluorine-containing resin (containing b- The present invention relates to a thermosetting resin composition.

The butyl etherified melamine formaldehyde resin (capacitor component) of the present invention has a number average molecular weight of 1700 or less, and those with a number average molecular weight exceeding 1700 have poor reactivity and compatibility. Further, the resin has one melamine nucleus and 3 to 5 ab-bonded formaldehyde atoms. If there are more than 5, the response will be slow.

If there are less than three, the pot life after mixing with component (B) will be shortened. Furthermore, component (4) has 0.5 to 2 dimethylol groups per melasone nucleus. If the number of methylol groups exceeds 2, the storage stability of the resin will be poor, and turbidity may occur during storage after being dissolved in an organic solvent. Furthermore, if the number is less than 0.5, the reactivity is poor. In the butyl etherified melamine-formaldehyde resin of the present invention, the bound formaldehyde is present as the above-mentioned methylol group.

Most of them are dietherized with butanol and present as butoxymethyl groups, the number of which is approximately 1 to 4 per melamine nucleus. In addition, the remainder of the bound formaldehyde serves as a crosslinking group between melamine nuclei by condensation of methylol groups.

In the present invention, the number average molecular weight is determined by gel permeation chromatography using a standard polystyrene calibration curve.

The butyl etherified melamine/formaldehyde resin of the present invention is produced by dissolving melamine in butanol.

There is a method in which addition and butyl etherification reaction is carried out while formaldehyde is added dropwise thereto, and a method in which melamine and formaldehyde are dissolved in butanol and this is heated to carry out addition and etherification reaction. In the second reaction, an acidic catalyst such as nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, para-toluenesulfonic acid, etc. is added, and the reaction is carried out under acidic conditions (preferably at pH 3 to 6).
It is preferable to carry out the reaction at a temperature of about 90 to 100° C., preferably at the reflux temperature of butanol.

The amount of raw materials to be charged is preferably 4 to 7 moles of butanol and 3 to 7 moles of formaldehyde per 1 mole of melamine.

The number of bound formaldehyde, butyl ether group, and methylol group per melamine nucleus in the butyl etherified melamine formaldehyde resin obtained in this way may be determined by nuclear magnetic resonance (NMR) spectroscopy, but You can also find it like this. The number of bound formaldehydes can be determined from the difference between the charged amount and the unreacted formaldehyde determined by the sodium sulfite method. The butyl ether group can be determined by adding an internal standard substance to the two reaction solutions, determining the amount of butanol (unreacted butanol amount) in the reaction solution by gas chromatography, and subtracting this from the amount of butanol charged. The methylol group can be determined by utilizing the number of butyl ether groups and from the area intensity ratio based on the butyl ether group and the methylol group in the NMR spectrum.

Among the components (B) of the present invention, the fluorine-containing resin (b-1) has an alkoxy group or a cyclohexyloxy group. This makes it possible to make it soluble in organic solvents such as xylene, toluene, butyl acetate, and methyl isobutyl ketone. Also, the molecular weight of 9 is approximately i, o o o ~ 200,0
00, especially about 10,000 to io
o, o o oO is preferred.

If the molecular weight is too low, weather resistance and chemical resistance tend to decrease.

The fluorine-containing resin (b-1) is a fluoroolefin such as chlorotrifluoroethylene, trifluoroethylene, or fluoroethylene; A copolymer obtained by copolymerizing alkyl vinyl ether or hasyclohexyl vinyl ether, such as ethyl vinyl ether, flobyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, etc., in which the hydrogen of the alkyl group or vinyl group is replaced with fluorine. Other ingredients include ethylene, propylene, imbutylene, and vinyl chloride.

Vinylidene chloride, vinyl acetate, vinyl n-butyrate.

It may also contain methyl methacrylate and the like as a copolymerization component.

Fluoroolefins have 40 to 60 moles of hydroxyl groups in the copolymer line, and hydroxyalkyl vinyl ethers have 10 to 100 moles of hydroxyl groups. In particular, it is preferably used so that the number is 10 to 70. If the amount of fluoroolefin is too small, the effect of improving weather resistance will be lowered, and it is difficult to introduce a large amount in terms of production.

The fluorine-containing resin (b-1) has a hydroxyl value of 10 to 100, preferably 10 to 70. If the hydroxyl value is less than 10, the curing reaction with component (3) will be insufficient; 6. io
If it exceeds o, the amount of hydroxyalkyl vinyl ether used increases, and solubility in organic solvents tends to be limited. From the viewpoint of solubility in organic solvents, the hydroxyalkyl vinyl ether is preferably used in an amount of 15 molar or less.

Moreover, it is preferable to use cyclohexyl vinyl ether and alkyl vinyl ether in a total amount of 5 to 60 molti in the fluorine-containing resin (b-1).

If the amount of cyclohexyl vinyl ether and alkyl vinyl ether is too small, the copolymer will be difficult to dissolve in organic solvents.

If it is too large, the amount of fluoroolefin or hydroxyalkyl vinyl ether used will decrease. In particular, it is preferable from the viewpoint of characteristics that cyclohexyl vinyl ether and hyalkyl vinyl ether are used in an amount of 5 to 45 mol %.

It is preferable that other components are used in the fluorine-containing resin (b-1) in an amount of 30 molar or less.

Of the components (B), the reactive carbon-carbon double bond in the modified fluorine-containing resin (b-2) is 90 to 100 g per 100 g of resin.
The fluororesin (X) has 0.055 mol and an alkoxy group or a cyclohexyloxy group.

The same fluorine-containing resin (b-1) is used. However, in this case, the hydroxyl group of the fluororesin is O~1
It is 00. Therefore, it does not necessarily contain hydroxyalkyl vinyl ether as a component.

? "The above fluororesin (xi p) having a reactive carbon-carbon double bond is the same as the above fluorine-containing resin (b-1) and has a hydroxyl value of 0.57 to 100 (copolymer z ), maleic anhydride, acrylic acid.

It can be obtained by reacting derivatives reactive with α, β-unsaturated carboxylic acids or hydroxyl groups, such as methacrylic acid, acrylic anhydride, methacrylic anhydride, and their acid chlorides. In this case, the α,β-unsaturated carboxylic acid derivative is preferably o,ooi to 0.055 mol based on copolymer 21009.

It is preferable to react in an amount of o, oos to 0.031 mol.

If it is too small, the effect of introducing graft points will be small, and if it is too large, the ethylenically unsaturated monomer (y) will tend to gel during polymerization.

Examples of the ethylenically unsaturated monomer (y) to be reacted in the presence of the fluorine-containing resin (X>) include methyl acrylate, ethyl acrylate, and butyl acrylate.

Alkyl acrylates such as isopropyl acrylate, 2-ethylhexyl acrylate-1, similar alkyl methacrylates, styrene or vinyltoluene, α-
Substituted styrenes such as methylstyrene and chlorostyrene, acrylonitrile, methacrylonitrile, vinyl chloride,
Vinyl acetate and maleic acid dialkyl esters can be used.

Furthermore, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate, similar hydroxyalkyl methacrylates, glycerin,
Monoacrylate polymers of polyhydric alcohols such as trimethylolpropane, or ethylenically unsaturated monomers having hydroxyl groups such as monomethacrylate-1., N-methylol acrylamide, and N-methylol methacrylamide can be used. Also, if necessary, acrylamide,
Unsaturated amides such as tacrylamide, unsaturated monomers with oxirane groups such as glycidyl methacrylate-1, glycidyl acrylate, and α,β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and maleic acid monoalkyl esters. Can be used. If too many unsaturated monomers containing unsaturated amide and oxirane groups are used, the water resistance of the coating film will decrease and the reaction solvent will be limited, so component (X) and component (y) It is preferable to use 30% by weight or less based on the total amount of α,β-unsaturated carboxylic acid, and since too much α, β-unsaturated carboxylic acid tends to reduce the water resistance of the coating film, it is recommended to use 10% by weight or less. preferable.

The modified fluorine-containing resin rb-2) of the present invention has the above (X)
It is obtained by polymerizing component (y) in the presence of the component.

Here, component (X) is 0.5 to 50% by weight and (y)
The ingredients are used in amounts of 99.5-50% by weight. The ratio of (X) component to (yl component) is (x)/(y) (weight ratio) 0.5
If it is less than /99.5, the weather resistance, chemical resistance, etc. of the coating film will deteriorate, and if it exceeds 50'150, gelation will occur easily during polymerization.

(X) component and (y) component are each 5 to 3.0
It is preferable to use it in an amount of 95 to 70% by weight.

・The hydroxyl value of the modified fluorine-containing resin (b-2) is preferably 10 to 150, and this depends on the hydroxyl value of component (X) and its usage amount, and the ethylenically unsaturated monomer having a hydroxyl group in component (y). The acid value can be adjusted by adjusting the amount of α,β-unsaturated carboxylic acid used in the yl component.

The polymerization of component (y) in the presence of component (X) can be carried out using toluene, xylene, methyl isobutyl ketone, butyl acetate, ethyl acetate, cellosolve acetate, if necessary.

Butyl cellosolve, 1-butanol, 2-butanol,
Using organic solvents such as 1-propertool and 2-propertool as reaction solvents, peroxides such as benzoyl peroxide, ditertiary-butyl peroxide, and cumene hydroperoxide, and azobisisobutyronitrile and the like are used as bipolymerization catalysts. 1 to 1 at 50 to 200°C using an azobis compound
This can be done by heating the reaction for 0 hours. The reaction is preferably carried out in an atmosphere or stream of an inert gas such as nitrogen gas, and peroxides are preferred as the double polymerization catalyst in terms of improving the grafting rate.

In order to reduce the amount of residual monomer, it is preferable to use a peroxide and an azobis-based compound in combination.

In the present invention, the butyl etherified melamine/formaldehyde resin and the fluorine-containing resin (b-1) and/or the modified fluorine-containing resin (b-2) are blended so that the weight ratio of the former to the latter is 5/95 to 50150. be done. Outside this range, coating film performance tends to be poor.

Further, the thermosetting resin composition according to 9 the present invention includes xylene,
Toluene, butyl cellosolve, ethyl cellosolve, n-
Can be used with organic solvents such as butanol, imbutanol, inclopanol, methanol, etc.

It is used in an appropriate solid content.

Depending on the purpose, pigments such as titanium white and other additives may be added to the thermosetting resin composition according to the present invention.

Further, as a coating method, spray painting, dipping, etc. can be adopted.

(Example) Next, two manufacturing examples and an example regarding the present invention will be shown. The following parts and h indicate parts by weight and % by weight, respectively.

Production Example 1 Melamine 1269. N-Butanol 4449 and 0.2 g of a 61% nitric acid aqueous solution were weighed out, heated to 100°C, and 225 g of paraformaldehyde was added in 6 equal intervals over 30 minutes, followed by a reaction at reflux temperature for 30 minutes. Moisture was removed and desolubization was performed so that the heating residue was 50%. The viscosity at this time was B (Cardona 125°C).

Production Example 2 Using the same equipment as in Production Example 1, 0.2 g of melamine 1269° n-butanol 2969,61 dinitric acid was weighed and taken out.
Raise the temperature to 0°C. A solution of paraformaldehyde 2259 dissolved in 148 g of n-butanol was added dropwise thereto over 30 minutes using a dropping pump. After that, the water was removed by reacting at reflux temperature for 30 minutes, and then the heating residue was 50
It fell off like it was going to become a chi. The viscosity at this time is (Cardona/
25°C) B.

Production Example 3 Using the same equipment as Production Example 1, 126 g of melamine, n
-444 g for pig/-, 61% nitric acid, 2 g.

Furthermore, 225g of paraformaldehyde was mixed and prepared.
After raising the temperature to 100°C, a reaction was carried out for 30 minutes.

Furthermore, reflux dehydration was performed for 30 minutes to remove moisture, and
Solvent removal was performed so that the heating residue was 50%. The viscosity at this time was C at Cardona (25°C).

Production Example 4 Using the same equipment as Production Example 1, paraformaldehyde 2
62.59.11-Butanol 444g and melamine 1
26 g was weighed out and an addition reaction was carried out at 90 to 100°C for 60 minutes. After that, it was cooled to 40-45°C and 0.7 talic acid was added.
1 g was added, and reflux dehydration and dissolution were performed under acidic conditions. After this, the heating residue was adjusted to 60%. The viscosity at this time is L. This product was adjusted with xylene so that the heating residue was 50%. The viscosity at this time was (Cardona/25°C) A.

Production Example 5 Using the same equipment as Production Example 1, paraformaldehyde 1
87.5g, n-butanol 3409 and melamine 12
6 g was weighed out and an addition reaction was carried out at 9.90 to 100°C for 60 minutes. After that, it is cooled to 40-45℃ to eliminate phthalic acid.
．． 29 was added, and reflux dehydration and dissolution were performed under acidic conditions. After this, the heating residue was adjusted to 60% with xylene. The viscosity at this time was (Cardona/25°C)W.

Production Example 6 Fluorine-containing copolymer having hydroxyl groups [hydroxyl value 52,
Molecular weight approximately 80,000. ) trifluoroethylene is a copolymer of hydroxyalkyl vinyl ether and alkyl vinyl ether;
A mixed solvent solution of xy7lene-methyl imptyl ketone containing about 50 mole [solid content: 50 mole, Lumiflon LF]
-200D, Asahi Glass (trade name used)] 100 parts, 1 part of maleic anhydride, and 1 part of xylene were placed in a flask equipped with a stirrer and a reflux condenser and heated at 50°C for 1 hour.
A fluorine-containing resin (1
) was synthesized. Next, 40 parts of this fluorine-containing resin (I) and 10 parts of n-'butanol were charged into a flask, and 120 parts of
12 parts of 2-hydroxyethyl methacrylate, 1.35 parts of butyl methacrylate, and 12.5 parts of ethyl acrylate.

18 parts of styrene, 2 parts of methacrylic acid. ．． A mixture of 5 parts of azobisisobutyronitrile, 2.5 parts of azobisisobutyronitrile, and 0.5 parts of di-t-butyl peroxide was added dropwise over 2 hours, then kept at the same temperature for 1 hour, and then heated to 140°C. A graft copolymer (modified fluorine-containing resin) was obtained by raising the temperature to 4 hours and reacting for 4 hours. Solvent (Nrubetsuso-100,
Esso Petrochemical Co., Ltd. (product name) was added.

Table 1 shows the number of formaldehyde bound per melamine nucleus, the number of butyl ether groups, the number of methylol groups, and the number average molecular weight of the butyl etherified melamine formaldehyde resins obtained in Production Examples 1 to 5.

However, the number of bound formaldehyde depends on the amount of preparation and the amount of unreacted formaldehyde measured by the sodium sulfite method.
The number of butyl ether groups was determined by the amount of butanol charged and measurement of unreacted butanol by gas chromatography using 5ec-butylbutanol as an internal standard solution, and the methylol group was determined from the number of butyl ether groups and the NM concentration spectrum. Also, the number average molecular weight.

The measurement was carried out by gel permeation chromatography under the following measurement conditions using a standard polystyrene calibration curve.

〔Measurement condition〕

Column: Hitachi Chemical ■Product name, GELKOR-4
20, R-430 and R-4403 are connected in series (number of theoretical plates: 17,000 plates/piece) Solvent: Tetrahydrofuran Flow rate: L? 7g/min Temperature: 23℃ Sample concentration: 300mg15m7 Injection amount: Detection at 200μ Instrument: Differential refractometer Example 1 30 parts by weight of butyl etherified melamine formaldehyde resin of Production Example 1, modified fluorine-containing resin of Production Example 4 70
Weigh out titanium white 50 heavy weight part in the weight part, mix it with 3 rolls, and then add thinner (xylene/Tsurupez-100 = 30/
70) was adjusted to Ford cup ÷ 420 seconds/25°C, and the coating was sprayed onto a board (Bonderite treated board Φ1441) to a film thickness of 30 to 35μ, left at room temperature for 20 minutes, and then baked at 130°C for 20 minutes. Table 3 shows the performance of the resulting coating film.

Examples 2 to 6 and Comparative Examples 1 to 2 A coating film performance test was conducted in the same manner as in Example 1 using the formulations shown in Table 2. The results are shown in Table 3.

The test method is as follows:

(1) Light intensity: Measured at 60° specular reflectance.

(2) Pencil hardness: Measured with Mitsubishi Pencil Uni.

(3) Cross cut; cut the coating surface with a cutter knife
After cutting 100 squares at In intervals and peeling them off with sellotape, judge by the number of squares remaining.

(4) Solvent resistance: gauze was soaked in xylene, placed on a coating plate, and the coated surface was evaluated after 1 hour.

○ No change stop (5) Impact: Impact was carried out using a DuPont impactor.

(6) Accelerated weathering: Q, UV accelerated weathering tester (US Q
-Pane1) was used.

UV irradiation at 50℃ for 4 hours Cycling for 4 hours at 50℃ with condensation exposed to standard conditions for a specified period of time. After that, measure the 60 degree specular reflectance. did.

(7) Paint film appearance: The clear paint obtained in the same manner as above, except that titanium white was not used, was applied to the glass plate and had good compatibility with baking, and the curing reaction was sufficient at a temperature lower than the conventional curing temperature. Indicates coating film characteristics.

Claims (1)

[Claims] 1. (A) Butyl etherified melamine having a number average molecular weight of 1,700 or less, 3 to 5 bound formaldehydes and 0.5 to 2 methylol groups per melamine nucleus.・Formaldehyde resin and (B) fluorine-containing resin (b-1) having a hydroxyl group and an alkoxy group or a cyclohexyl group and/or a reactive carbon-carbon double bond of 0 to 0 per 100 g of resin.
．． Modified fluorine-containing resin (b-2) obtained by polymerizing an ethylenically unsaturated monomer (y) in the presence of a fluorine-containing resin (x) having 055 mol and an alkoxy group or a cyclohexyloxy group, and having a hydroxyl group A thermosetting resin composition comprising: