JPS6029753B2 - UV curable resin composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to an ultraviolet curable resin composition.

Conventionally, ultraviolet curable resins containing polymer monomers have been used mainly in the field of coatings because they are solvent-free and long-curing. The polymerizable monomer used in this process is overwhelmingly styrene monomer, and a considerable amount of it evaporates during the curing process, making it subject to air pollution regulations. For this reason, it has been considered to use monomers with low brightness and high boiling points as polymerizable monomers, but these monomers have too high a viscosity, are too unstable, and are too expensive to be practical. has its drawbacks. However, when the present inventors mix a very special monomer called (poly)ethylene glycol monoalkyl ether acrylate as a polymerizable monomer, the viscosity of the ultraviolet curable resin composition depends on the viscosity of the monomer itself and the resin. After discovering the surprising fact that the molecular weight is low compared to the molecular weight of
1500 ultraviolet curable resin and a (poly)ethylene glycol monomer whose molecular structure is represented by (where R is day or CH3, n is 1, 2 or 3, R2 is C ratio, C2day5, or C3day7). An ultraviolet curable resin composition composed of alkyl ether acrylate exhibits properties of low viscosity, fast curing, high boiling point, and excellent adhesion to metals, and exhibits excellent properties when applied as a paint for coating metals, for example. This discovery led to the completion of the present invention.

In the future, there is a tendency for ultraviolet irradiation technology to be actively adopted in the metal painting field, but the scale of the painting process is also increasing, and the trend is to improve productivity and save energy by creating lines, and thin coating films are required. As a result, there is a tendency for paints with a high monomer volatilization rate to be used, and on the other hand, there is an even stricter demand for pollution-free paints.The ultraviolet curable paint of the present invention can meet these demands. It is a resin composition.

In other words, the low viscosity meets the requirements for workability, particularly thin film coating, the fast curing capability meets the demands for improved productivity and energy savings, and the high boiling point meets the demands for non-pollution. be. In particular, low viscosity is the most characteristic property of the composition of the present invention, but when acrylate and ultraviolet curable resin, which have been conventionally used as high-boiling point monomers, are blended, a composition with an extremely higher viscosity than when styrene is blended. However, only a very special monomer, a specific (poly)ethylene glycol monoalkyl ether acrylate, has a viscosity of 2~&ps.
(at 25°C) and other acrylates, such as tetrahydrofurfuryl acrylate, but when combined with UV-curable resins, the viscosity becomes lower than other acrylates, and the viscosity is close to that of styrene formulations. They discovered the surprising fact that a composition of can be obtained. For metal coating paints, specific unsaturated polyester resins among ultraviolet curable resins, such as air-drying unsaturated polyester resins made of maleic acid, propylene glycol and diallyltrimethylolpropane, and specific (poly)ethylene glycol monomers of the present invention are used. Compositions made of alkyl ether acrylate exhibit the best properties in terms of both workability and physical properties of the coating film. Examples of the ultraviolet curable resin used in the present invention include unsaturated polyester resins, epoxy acrylic resins, and urethane acrylic resins having a molecular weight of 250 to 1,500.

The above-mentioned unsaturated polyester resins mainly include ethylenically unsaturated dibasic acids such as maleic acid, fumaric acid, itaconic acid, or anhydrides thereof, and ethylene glycol, diethyl glycol, triethylene glycol, neobentyl glycol, and benthyl glycol. Condensation products consisting of polyhydric alcohols such as toll, trimethylolethane, trimethylolpropane, and hydroxylbentadiene;
Further examples include condensation products obtained by reacting triallylbentaylythritol, diallyltrimethylolpropane, monoallyl glycerin ether, and the like. The above-mentioned epoxy acrylic resins include pisphenol A type epoxy resin, bisphenol F type epoxy resin, halogenated bisphenol type epoxy resin, resorcin type epoxy resin, novolak type epoxy resin, fat moat type epoxy resin, dicarboxylic acid modified epoxy resin, and glycerin. Acrylic acid, glycidyl ether, epoxidized soybean oil, triglycidyl isocyanurate, etc.
Examples include methacrylic acid, phthalic anhydride and hydroxyacrylate adducts, and succinic anhydride and hydroxyacrylate adducts with an acryloyl group added.

The above urethane acrylic resins include tolylene diisocyanate, xylylene-1,4 diisocyanate, 1,6
Examples include those in which hexamethylene diisocyanate or the like is reacted with trimethylolpropane, glycerin, or pentaerythritol, and hydroxy (meth)acrylate is added to the remaining NCO group.

Among these, specific unsaturated polyester resins having an allyl group and excellent air drying properties, such as diallyltrimethylolpropane or triallylbentaerythritol, are preferred.

The molecular weight is preferably 250 to 1,500. If the molecular weight is less than 250, the molecular weight of the prepolymer is too small, and the drying performance is delayed, making it impossible to fully demonstrate the air drying performance. If it is too large, the molecular weight of the prepolymer is too large and the viscosity of the paint becomes too high.If the viscosity is lowered in consideration of coatability, the content of one monomer component will be excessive and air drying will be delayed, so neither is preferable.

Examples of the (poly)ethylene glycol monoalkyl ether acrylate used in the present invention include ethylene glycol monomethyl ether (meth)acrylate, ethylene glycol monoethyl ether (meth)acrylate,
Diethylene glycol monomethyl ether (meth)acrylate, diethylene glycol monoethyl ether (
Examples include meth)acrylate, diethylene glycol mono-n-propyl ether (meth)acrylate, triethylene glycol monoethyl ether (meth)acrylate, among others, diethylene glycol monomethyl ether acrylate and diethylene glycol monoethyl ether acrylate. Viscosity, UV curability,
It is advantageous in terms of cost. Note that the same effect is obtained when the (poly)ethylene glycol structure portion is partially blocked with propylene glycol. The composition of the present invention can be used alone or in combination with commonly used additives as a paint.

Compounding agents include photosensitizers such as penzoin isopropyl ether, benzoin isobutyl ether, and benzoin ethyl ether, paint additives such as pigments, and fillers, as well as additives for coatings, especially for improving adhesion. is hydroxy (meth)
About 10% of a glycidyl ether compound such as a phosphoric acid ester of acrylate, a monoethanolamine phosphoric ester, glycidyl (meth)acrylate, or an epoxy resin having an epoxy equivalent of 300 or less is used in combination. In addition, low boiling point monomers such as styrene can also be used in combination in small amounts. Next, the present invention will be explained with reference to Examples.

Example 1 0.7 mol of maleic anhydride, 0.3 mol of phthalic anhydride,
Put 1.13 mol of propylene glycol and 0.2 mol of trimethylolpropane diallyl ether into a four-necked flask, cook at 170 pm for 5 hours, and then cook at 150 qo for 30 minutes under a reduced pressure of 1 Kg. The reaction was continued and stopped when the acid value of the resin reached 40.

To the resin obtained in the above reaction, 100 parts of diethylene glycol monoethyl ether acrylate and 3 parts of penzoinisopropyl ether were added to prepare an ultraviolet curable resin composition.

The viscosity of this composition was very low at 7 ratio p (20°C, 6pm). Apply the above composition to the iron plate using bar coater #
16, high pressure mercury lamp (80W/arc, 10g height,
When it was irradiated with ultraviolet rays using LOOO000REOW/, it was cured in a very short time of 2 seconds.

Comparative Example 1 When tetrahydrofurfuryl acrylate was used in place of diethylene glycol monoethyl ether acrylate in Example 1, the viscosity was as high as 15 ratio p, and the curing time was as long as 5 seconds.

Example 2 The ultraviolet curable composition of Example 1 was uniformly applied to a black-skinned steel pipe moving on guide rolls to a film thickness of 10 mm using an automatic sprayer, and immediately after that, a dispersed light beam of 80 W/arc was applied. Type mountain v
The lamp was irradiated for 2 seconds from three directions.

As a result, the coating was carried out smoothly without any adhesion to the guide rolls. Example 3 To 256 parts of a bisphenol A type epoxy resin having an epoxy equivalent weight of 128, 18 parts of methacrylic acid and trimethylbenzylammonium salt were added.

Ride 0.2 parts, hydroquinone monomethyl ether 0
．． 05 parts were added thereto and reacted at 100°C for 6 hours. An ultraviolet curable resin composition was prepared by adding 100 parts of the obtained resin, 10 parts of diethylene glycol monoethyl ether acrylate, and 3 parts of penzoinisopropyl ether.
The viscosity of this composition was 10 ps, and the curing time was 2.9 ps as measured in the same manner as in Example 1. Example 4 14 parts of tolylene diisocyanate, 3 parts of trimethylolpropane, and 1 part of propylene glycol were placed in a flask and reacted at 90 qo for 5 hours.

Next, 110 parts of hydroxylethyl methacrylate and 0.0 parts of hydroquinone monomethyl ether were added to this product.
3 parts were added and reacted for 60 hours for 6 hours. Resin 1 obtained
0 base part and diethylene glycol mo/ethyl ether acrylate 10 anchor part and penzoin isopropyl ether 3
part was added to prepare an ultraviolet curable resin composition. The viscosity of this composition was 20 ps and the curing time was 1 second as measured in the same manner as in Example 1. Example 5 0.6 mol of maleic anhydride, 0.4 mol of phthalic anhydride,
Pour 1.25 mol of propylene glycol into a flask and raise the temperature to 12,000 degrees Celsius, then 170 degrees Celsius for 2 hours.
After reacting for 5 hours, the reaction was continued for 30 minutes under reduced pressure until the acid value reached 2.
Resin No. 3 was obtained.

Next, 10 parts of the obtained resin, 10 parts of diethylene glycol monomethyl ether acrylate, and 5 parts of benzoin ethyl ether were added to obtain a paint having a food cup viscosity of 20,000 sand. This paint was applied to a mild steel plate using a #12 bar coater and immediately passed through an ultraviolet irradiation oven (output 80 W/skin) under a nitrogen atmosphere, whereupon it was completely cured in 1.5 seconds.

Control Example 2 10 parts of the same resin as in Example 1 were mixed and dissolved with 10 parts of diethylene glycol monoacrylate and 3 parts of penzoin isobutyl ether, but the compatibility was poor and the two phases separated. However, it was not considered practical.

Control Example 3 Ultraviolet curable resin composition obtained by mixing and dissolving 100 parts of diethylene glycol monobutyl ether acrylate and 3 parts of penzoinisobutyl ether in 10$ of the same resin as in Example 1. When the material was irradiated with ultraviolet rays in the same manner as in Example 1, the curing time was 5 seconds, but the viscosity was 30 ps.
There were problems with coating properties.

Control Example 4 An ultraviolet curable resin composition was prepared by mixing and dissolving 10 parts of tetraethylene glycol monoethyl ether acrylate and 3 parts of penzoin isopropyl ether in 10 parts of the same resin as in Example 1. When UV irradiation was performed in the same manner as in Example 1, the curing time was 5 seconds, but the viscosity was 40.
The specific ps was high and there was a problem in coatability.

Control Example 5 An ultraviolet curable resin composition was prepared by mixing and dissolving 100 parts of styrene monomer and 3 parts of penzoysopropylene into 10 parts of the same resin as in Example 1.

Claims (1)

[Claims] 1. An ultraviolet curable resin with a molecular weight of 250 to 1500 selected from allyl group-containing unsaturated polyester resins, epoxy acrylic resins, and urethane acrylic resins and a molecular structure of ▲
There are mathematical formulas, chemical formulas, tables, etc.▼ (However, R_1 is H or CH_3, n is 1, 2 or 3,
R_2 is an ultraviolet curable resin composition made of (poly)ethylene glycol monoalkyl ether acrylate represented by CH_3, C_2H_5 or C_3H_7. 2. The composition according to claim 1, wherein the (poly)ethylene glycol monoalkyl ether acrylate is diethylene glycol monomethyl ether acrylate or diethylene glycol monoethyl ether acrylate.