JPH0665489A - Oil-free alkyd resin composition and paint - Google Patents

Abstract

PURPOSE:To provide the subject one-pack type composition containing a resin produced by the addition reaction of epsilon-caprolactone to a specific oil-free alkyd resin, having excellent chipping resistance and smoothness and practical hardness and suitable as an intercoating paint for automobile, etc. CONSTITUTION:The objective composition contains a resin produced by the addition reaction of (A) epsilon-caprolactone to (B) an oil-free alkyd resin having a number-average molecular weight of 1,000-6,000, an acid value (in terms of solid) of 1-40 and a hydroxyl value (in terms of solid) of 50-250. The component B is preferably produced by esterifying a polyhydric alcohol such as neopentyl glycol with a polybasic acid such as phthalic acid by melting process, solvent process, etc. The amount of the component A to be added to the component B is preferably 40-80mol% of the theoretical average number of the hydroxyl groups of the component B. The addition reaction between the components A and B is carried out preferably at 150-200 deg.C while keeping the temperature until the viscosity of the produced resin becomes constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-free alkyd resin composition having excellent balance of hardness, smoothness, chipping resistance, etc. of a coating film as a thermosetting resin and a coating material.

[0002]

2. Description of the Related Art In recent years, intermediate coatings applied to automobile outer panels are chipping-resistant and top-coating coatings for protecting them from rust and corrosion caused by collision of pebbles during traveling with the vehicle body. There is a growing demand for improved smoothness of the intermediate coating film in order to improve the appearance of the subsequent coating film. In order to meet these needs, oil-free alkyd resin / melamine resin system, oil-free alkyd resin / polyether resin / melamine resin system (JP-A-63-128080, etc.), oil-free alkyd resin / blocked isocyanate resin system , Oil-free alkyd resin / linear low molecular weight polyester resin / polyisocyanate resin system (Japanese Patent Laid-Open No. 64-38479, etc.) have been studied.

However, the oil-free alkyd resin / melamine resin system can improve the chipping resistance and smoothness by softening the oil-free alkyd resin, but the hardness decreases, and the oil-free alkyd resin / melamine resin /
Similarly, the polyether resin / melamine resin system has the drawback that the chipping resistance is improved but the hardness is lowered. The oil-free alkyd resin / blocked isocyanate resin system can improve chipping resistance, but its smoothness is still insufficient, and since it uses blocked isocyanate, it requires high temperature for curing. have. In addition, the oil-free alkyd resin / linear low-molecular-weight polyester resin / polyisocyanate resin system easily balances chipping resistance, smoothness, and hardness, but since it is a two-part type, it has the drawback of limiting the pot life of the paint. .

[0004]

Therefore, the present invention is a one-pack type oil-free alkyd resin composition which is excellent in chipping resistance and smoothness and which has practical hardness and is suitable for use as an intermediate coating for automobiles. And paints.

[0005]

According to the present invention, the distance from the main chain to the hydroxyl group, which is the reaction point, is lengthened and softened by subjecting the hydroxyl group of a specific oil-free alkyd resin to ring-opening and addition reaction of ε-caprolactone. Thereby, a coating film having a high crosslink density and a flexible coating film is formed, which is superior in hardness to the conventional improvement by softening and improves chipping resistance and smoothness. That is, in the present invention, the number average molecular weight is 1,000 to 6,000, the acid value (solid content) is 1 to 40, and the hydroxyl value (solid content) is 50 to 250.
And an oil-free alkyd resin (A) containing a resin (C) obtained by addition-reacting ε-caprolactone (B) with the oil-free alkyd resin (A), and a coating composition containing the same.

The oil-free alkyd resin (A) is mainly composed of a polyhydric alcohol having two or more hydroxyl groups in one molecule and a polybasic acid having two or more carboxyl groups in one molecule, and has a desired acid value. Can be obtained by reacting. The polyhydric alcohol used is neopentyl glycol,
2,2-dimethyl-3-hydroxypropyl-2,2-
Dimethyl-3-hydroxypropionate, trimethylolethane, trimethylolpropane, 2,2-diethyl-1,3-propanediol, 2-n-butyl-2-
Ethyl-1,3-propanediol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,
There are 6-hexanediol, 3-methyl-1,5-pentanediol, glycerin, 1,4-cyclohexanedimethanol, tris (2-hydroxyethyl) isocyanurate, spiroglycol, hydrogenated bisphenol, bisphenol A, and the like. Examples include monofunctional or polyfunctional epoxy compounds. These 1 type, or 2 or more types can be used in combination as appropriate. As the polybasic acid, phthalic acid or its anhydride, isophthalic acid, terephthalic acid, dimethyl terephthalate, trimellitic anhydride, adipic acid, sebacic acid, azelaic acid, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, dimethyl- 1,4-cyclohexanedicarboxylic acid and the like can be mentioned. These can be used alone or in combination of two or more.

A publicly known manufacturing method in which the above respective components are blended,
For example, the oil-free alkyd resin (A) is produced by esterification by a melting method, a solvent method or the like. The oil-free alkyd resin (A) thus obtained has a number average molecular weight of 1,000 to 6,000, preferably 2,000 to
Adjusted to 4,000. When the number average molecular weight is less than 1,000, the strength and chipping resistance of the coating film are reduced,
When it exceeds 0, the smoothness of the coating film is deteriorated. The number average molecular weight in the present invention means a value measured by a gel permeation chromatography method and converted using a standard polystyrene calibration curve. The acid value (solid content) of this oil-free alkyd resin (A) is in the range of 1-40,
It is preferably 5 to 25. If the acid value is less than 1, the resulting coating film has poor curability, and thus the coating film has poor hardness and chipping resistance. If it exceeds 40, the moisture resistance and smoothness are poor. Further, the hydroxyl value (solid content) of this oil-free alkyd resin (A) is in the range of 50 to 250, preferably 7
It is 0 to 200. If the hydroxyl value is less than 50, the hardness and chipping resistance of the coating film will be poor, and if it exceeds 250, the smoothness will be poor.
The strength of the coating film is poor. The number average molecular weight and the hydroxyl value can be set within the above ranges by selecting the type of each component, determining the compounding ratio thereof, and adjusting the acid value at the time of production.

The resin (C) is preferably 30 mol% to 100 mol%, particularly preferably 40 mol% to FOH (theoretical average number of hydroxyl groups in one molecule) of the oil-free alkyd resin (A) obtained above. 80 mol% is obtained by ring-opening and addition reaction with ε-caprolactone (B). If it is less than 30 mol%, it is difficult to obtain the desired smoothness and chipping resistance. If it exceeds 100 mol%, ε-caprolactone (B)
Remains unreacted in the coating film, and hardness, moisture resistance, and coating film strength tend to decrease. Further, in the present invention, it is essential that the ε-caprolactone (B) is subjected to ring-opening and addition reaction to the hydroxyl group of the oil-free alkyd resin (A), and as is known, ε-caprolactone is used as one kind of polyhydric alcohol. When incorporated into the main chain of an oil-free alkyd resin, the balance between chipping resistance and hardness becomes unbalanced.

FOH is a theoretical value of the average number of hydroxyl groups in one molecule, and is represented by the following formula (1).

[Equation 1] Can be obtained by Here, R is (a) / of the raw material polyhydric alcohol component (a) and the raw material polybasic acid (b) /
It is the equivalent ratio of (b), PB is the reaction rate (equivalent) of the starting polyhydric alcohol, and N is the number obtained by dividing the total number of moles of the starting material by the total number of acid equivalents of the starting material. The reaction rate of the raw material alcohol can be determined by setting the acid value of the produced resin or by measuring the acid value of the produced resin.
Further, the compounding amount of ε-caprolactone (B) is represented by the following formula (2).

[Equation 2] Can be obtained by Where FOH is the formula (1)
S is a value obtained from the above, S is determined by setting the amount of ε-caprolactone to be subjected to the addition reaction (for example, if 30 mol% to FOH, S = 0.3), and m is ε.
-The molecular weight of caprolactone (114). Mn is ε
-Theoretical number average molecular weight of the oil-free alkyd resin (A) before the caprolactone addition reaction. W is the weight of the oil-free alkyd resin (A) before the addition reaction of ε-caprolactone. ε-caprolactone addition reaction is 150 to 2
It is carried out by keeping the resin at 00 ° C. until the viscosity becomes constant. When a catalyst is used, tetrabutyl titanate, tetraisopropyl titanate or the like is added in an amount of 0.1 to 0.5% by weight based on the weight of ε-caprolactone. By doing so, the addition reaction time can be shortened.

In the oil-free alkyd resin composition of the present invention, an amino resin can be used as a curing agent, or a blocked isocyanate resin or the like can be used in combination. Examples of the amino resin include those obtained by addition-condensing an amino compound such as melamine and benzoguanamine with formaldehyde, and further alkyl-etherifying with a lower alcohol such as methanol, isobutanol, and n-butanol. Amino resin and ε-caprolactone-added oil-free alkyd resin (C) are the former /
The latter is preferably added in a weight ratio of 40/60 to 10/90. If this ratio becomes too large, the strength and chipping resistance of the coating film will tend to decrease, and if it becomes too small, the hardness and moisture resistance of the coating film will tend to decrease. The blocked polyisocyanate resin is a compound having two or more isocyanate groups in one molecule. For example, hexamethylene diisocyanate trimer, isophorone diisocyanate trimer, or the like is used as ethyl acetoacetate or ε-caprolactam. Some are blocked by etc. When the block polyisocyanate resin is used in combination, 40% by weight or less of the amino resin is preferable,
If this amount is exceeded, the adhesion to the top coat film tends to decrease, and it is necessary to raise the curing temperature.

The oil-free alkyd resin composition of the present invention is a coloring pigment such as rutile-type titanium white, iron oxide, carbon, phthalocyanine blue, an extender pigment such as precipitated barium sulfate and barium carbonate, and a pigment dispersant, if necessary. Is added and dispersed, and then an amino resin as a curing agent,
A coating material can be prepared by adding a leveling agent or the like, appropriately selecting from an ester-based, aromatic-based, ketone-based, alcohol-based solvent, etc., and diluting it to an appropriate viscosity.
The coating material containing the oil-free alkyd resin composition of the present invention is, for example, 30-50 μm on a cationic electrodeposition plate.
(Dry film thickness), 20 ~ 30 at 120 ~ 150 ℃
It can be baked for minutes. Furthermore, by coating an acrylic resin-based topcoat paint containing an aluminum pigment or the like, a coating film for an automobile outer panel having excellent smoothness and chipping resistance can be obtained.

[0012]

EXAMPLES The present invention will be described in detail below with reference to examples. Parts and% in each example represent parts by weight and% by weight, respectively. Example 1 (A) 121.7 parts of neopentyl glycol and 68.5 parts of trimethylolpropane were placed in a 1-liter four-necked flask equipped with a stir bar, a thermometer, a reflux condenser with a rectification column, and a nitrogen gas introducing device. , 1,6-hexanediol 25.0
Parts, versatic acid monoglycidyl ester 50.0
And 192.8 parts of isophthalic acid were charged and the temperature was raised. 1
After the temperature was raised from 80 ° C. to 220 ° C. over 4 hours, the reaction was continued at the same temperature until the acid value reached 25.5, and the mixture was cooled. Next, 25.0 parts of hexahydrophthalic anhydride and 75.0 parts of adipic acid were charged and the temperature was raised. The temperature was raised from 160 ° C to 210 ° C over 3 hours, the reaction was continued at the same temperature until the acid value became 10.3, and after cooling to 180 ° C, 63.5 parts of ε-caprolactone, tetrabutyl titanate 0 .15 parts were charged and the reaction was continued at the same temperature. Cooled after 3 hours of no viscosity change, xylol / butyl cellosolve = 9
The solid content was adjusted to 60% at a ratio of 1/1 (weight ratio). (B) Production of paint and preparation of test piece Oil-free alkyd resin 103.8 obtained in (A)
Part, Taipaque R-930 (rutile type titanium white, made by Ishihara Sangyo) 60.0 parts, FW-200 (carbon, made by Degussa) 0.1 part, BYK161 (pigment dispersant, made by BYKEMI) 1.2 parts Were mixed and dispersed with a three-roll mill to 1 μm or less. Next, melan 220 (n-butylated melamine resin, manufactured by Hitachi Chemical Co., Ltd., solid content 70%) 32.
After adding 1 part and mixing, the thinner (Solvesso-10
0 / xylol / butyl acetate / butyl cellosolve = 60
/ 20/10/10 (weight ratio)) Ford Cup #
It was diluted to 4, 20 seconds (20 ° C.) to prepare a paint. BYK354 (leveling agent, manufactured by BYKEMI) was added to the diluted coating material in an amount of 0.2% and mixed. Then, this coating material was applied onto a cationic electrodeposition plate (70 × 150 × 0.8 mm, manufactured by Nippon Test Panel Co., Ltd.) by air spraying so as to have a thickness of 40 to 50 μm (dry film thickness), and after setting for 5 minutes, 14
It was baked at 0 ° C. for 30 minutes to prepare a test plate for measuring smoothness and hardness. Further, an acrylic top coat was applied to the test plate to prepare a chipping-resistant test plate. Topcoat paint is Hitaroid 25 as a base coat paint.
86E (acrylic resin, manufactured by Hitachi Chemical Co., Ltd.) 70
Parts, melanin 28 (i-butylated melamine resin, manufactured by Hitachi Chemical Co., Ltd.) 25.0 parts, MEP 1700NL (aluminum dispersion, manufactured by Toyo Aluminum) 5.0 parts, and thinner (xylol / butyl acetate / i-Butanol / methyl isobutyl ketone = 60/15/10/15 (weight ratio))
Ford cup # 4, diluted for 16 seconds (20 ° C) with a Hitaroid 250 as a top coat paint
0A (acrylic resin, manufactured by Hitachi Chemical Co., Ltd.) 70.0
And 25.0 parts of Melan 28 were mixed and diluted with thinner (Solvesso-100 / Solvesso-150 = 25/75 (weight ratio)) to Ford cup # 4 for 25 seconds (20 ° C.). 10 to 10 of the above base coat paints
After coating to 15 μm (dry film thickness) and setting for 3 minutes,
The top coat paint was applied to 25 to 30 μm (dry film thickness). After setting for 5 minutes, it was baked at 140 ° C. for 30 minutes.

Example 2 (A) 146.8 parts of neopentyl glycol and trimethylolpropane 67 were placed in a 1-liter four-necked flask equipped with a stirring rod, a thermometer, a reflux condenser with a rectification column, and a nitrogen gas introducing device. .8 parts, 50.0 parts of versatic acid monoglycidyl ester, 110.1 parts of isophthalic acid were charged,
The temperature was raised. After heating from 180 ° C to 220 ° C over 4 hours, the reaction was continued at the same temperature until the acid value reached 23.0.
Cooled. Next, hexahydrophthalic anhydride 25.0
Parts, phthalic anhydride 75.0 parts, and adipic acid 75.0 parts were charged and the temperature was raised. The temperature was raised from 160 ° C to 210 ° C over 3 hours, the reaction was continued at the same temperature until the acid value reached 7.2, and after cooling to 180 ° C, ε-caprolactone 50.8
And 0.1 part of tetrabutyl titanate were charged and the reaction was continued at the same temperature. Cooled because the viscosity did not change in 3 hours, xylol / butyl cellosolve = 9/1 (weight ratio)
To 60% solids. (B) Production of paint and preparation of test piece A paint and a test plate were prepared in the same manner as in (B) of Example 1.

Example 3 (A) 130.8 parts of neopentyl glycol and 80 parts of trimethylolpropane in a 1-liter four-necked flask equipped with a stirring bar, a thermometer, a reflux condenser with a rectification column, and a nitrogen gas introducing device. .9 parts, 1,6 hexanediol 25.0
Parts, hydrogenated bisphenol A 25.0 parts and isophthalic acid 190.0 parts were charged and the temperature was raised. 220 from 180 ℃
After heating to 4 ° C for 4 hours, the reaction was continued at the same temperature until the acid value reached 28.0, and the mixture was cooled. Next, adipic acid 11
6.7 parts were charged and the temperature was raised. The temperature was raised from 160 ° C to 210 ° C over 3 hours, the reaction was continued at the same temperature until the acid value reached 10.5, and after cooling to 180 ° C, 92.5 parts of ε-caprolactone, tetrabutyl titanate 0 2 parts were charged and the reaction was continued at the same temperature. Cooled because the viscosity did not change in 3 hours, xylol / butyl cellosolve = 9/1
The solid content was adjusted to 60% by weight ratio. (B) Production of paint and preparation of test piece A paint and a test plate were prepared in the same manner as in (B) of Example 1.

Example 4 (A) 122.9 parts of neopentyl glycol and 70 parts of trimethylolpropane were placed in a 1-liter four-necked flask equipped with a stirring bar, a thermometer, a reflux condenser with a rectification column, and a nitrogen gas introducing device. 0.3 parts, 1,6-hexanediol 25.0
Parts, hydrogenated bisphenol A 50.0 parts, and isophthalic acid 175.0 parts were charged and the temperature was raised. 220 from 180 ℃
After heating to 4 ° C. for 4 hours, the reaction was continued at the same temperature until the acid value reached 27.0, and the mixture was cooled. Next, adipic acid 12
3.6 parts were charged and the temperature was raised. The temperature was raised from 160 ° C to 210 ° C over 3 hours, the reaction was continued at the same temperature until the acid value reached 8.2, and after cooling to 180 ° C, 97.4 parts of ε-caprolactone and tetrabutyl titanate 0 2 parts were charged and the reaction was continued at the same temperature. Cooled because the viscosity did not change in 3 hours, xylol / butyl cellosolve = 9/1
The solid content was adjusted to 60% by weight ratio. (B) Production of paint and preparation of test piece A paint and a test plate were prepared in the same manner as in (B) of Example 1.

Comparative Example 1 (A) 119.0 parts of neopentyl glycol and 80 parts of trimethylolpropane were placed in a 1-liter four-necked flask equipped with a stirring bar, a thermometer, a reflux condenser with a rectification column, and a nitrogen gas introducing device. 2.8 parts, hydrogenated bisphenol A 50.0
And 167.4 parts of isophthalic acid were charged and the temperature was raised. 1
After heating from 80 ° C. to 220 ° C. over 4 hours, the reaction was continued at the same temperature until the acid value reached 26.7 and cooled. Next, 120.8 parts of adipic acid was charged and the temperature was raised. 160 ° C
To 210 ° C over 3 hours, the reaction is continued at the same temperature until the acid value becomes 8.2, and after cooling to 180 ° C, the solid content is xylol / butyl cellosolve = 9/1 (weight ratio). It was adjusted to 60%. (B) Production of paint and preparation of test piece A paint and a test plate were prepared in the same manner as in (B) of Example 1.

Comparative Example 2 (A) 82.0 parts of neopentyl glycol and 106 of trimethylolpropane were placed in a 1-liter four-necked flask equipped with a stirring rod, a thermometer, a reflux condenser with a rectification column, and a nitrogen gas introducing device. .3 parts, versatic acid monoglycidyl ester 50.0 parts, 1,6 hexanediol 50.0 parts,
155.0 parts of isophthalic acid was charged and the temperature was raised. 180
After the temperature was raised from 0 ° C to 220 ° C over 4 hours, the reaction was continued at the same temperature until the acid value reached 24.0, and the mixture was cooled. Next, 148.6 parts of adipic acid was charged and the temperature was raised. The temperature was raised from 160 ° C to 210 ° C over 3 hours, and the acid value was 9.
The reaction was continued until it reached 7, and after cooling to 180 ° C., the solid content was 6 with xylol / butyl cellosolve = 9/1 (weight ratio).
It was adjusted to 0%. (B) Production of paint and preparation of test piece A paint and a test plate were prepared in the same manner as in (B) of Example 1.

The formulations and coating performances of Examples and Comparative Examples are shown in Table 1.
It was shown to.

[Table 1] Note) 1) Gloss: The specular reflectance at 60 ° was measured with a Suga Test Instruments gloss meter. 2) Smoothness: The smoothness of the coating film was visually evaluated according to the following criteria. ◎ Very good ○ Good △ Almost good ×
Poor 3) Hardness: A Mitsubishi Uni-Pencil was used to measure the hardness when the coating film was not scratched. 4) Chipping resistance: Using a stepping stone tester manufactured by Suga Test Machine,
50 g of No. 7 crushed stone was added to a test plate cooled at -20 ° C for 2 hours
After blasting at atmospheric pressure, the degree of cracking and peeling of the coating film was visually evaluated according to the following criteria. ◎ Very good ○ Good △ Almost good ×
Poor 5) Moisture resistance: Tested with a Suga Test Instruments wet tester under conditions of 50 ± 1 ° C. and relative humidity of 98% or more. The determination is A. S. T.
Based on M.

[0019]

INDUSTRIAL APPLICABILITY The oil-free alkyd resin composition according to the present invention is useful as a thermosetting coating material, and particularly produces a coating film having excellent smoothness, chipping resistance and hardness as an intermediate resin for automobiles.

Claims (3)

[Claims] 1. A number average molecular weight of 1,000 to 6,000.
Resin (C) obtained by addition-reacting ε-caprolactone (B) with an oil-free alkyd resin (A) having an acid value (solid content) of 1 to 40 and a hydroxyl value (solid content) of 50 to 250. An oil-free alkyd resin composition containing. 2. The amount of ε-caprolactone (B) to be subjected to the addition reaction is controlled by the FOH of the oil-free alkyd resin (A).
30 to 100 mol% of (theoretical average number of hydroxyl groups in one molecule)
The oil-free alkyd resin composition according to claim 1. 3. A paint containing the oil-free alkyd resin composition according to claim 1.