JPS6050220B2 - UV curable coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to curable coating compositions, particularly curable coating compositions for inks, which are curable by ultraviolet irradiation and contain novel resins.

In recent years, with the development of printing technology, there has been a demand for faster printing speeds.

Along with this, demands on the drying speed (curing speed) of printing ink are becoming increasingly strict. BACKGROUND ART Conventionally, as a drying means in high-speed printing, printed matter has been dried using a direct flame method or a hot air method. The printing ink used in such heat set printing is dried by heating to evaporate 30 to 40% of the solvent contained in the printing ink. Therefore, in printing factories that perform heatset printing, solvent vapor is often discharged, which often poses a pollution problem. Therefore, those skilled in the art would like an ink that can be dried by some means without containing such volatile substances. Under these circumstances, there is a trend towards ultraviolet curable ink as a printing ink that dries without solvent evaporation and has a fast drying rate, and several proposals have already been made5.

The applicant of this application is Japanese Patent Application No. 48-18325
124133), when a resin obtained by esterifying a copolymer resin of dicyclopentadiene and allyl alcohol with acrylic acid or methacrylic acid is used in a curable ink, it has good emulsification suitability and crosslinking property. It has been disclosed that it exhibits excellent performance. An ultraviolet curable coating composition using this resin contains an addition polymerizable prepolymer, a monomer, and a photosensitizer as main components. Among these photosensitizers, derivatives of benzophenone and benzoin are generally used, but since these sensitizers have low photoinitiation efficiency, they can be added in excess to the coating composition to improve photocurability. It is improving. For this reason, in ultraviolet curable coating compositions, especially printing inks, excessive photosensitizers cause problems such as swelling of the rollers and blankets of printing presses, as well as odor, volatility, and migration. In order to improve such drawbacks, JP-A-48-61460 discloses an alkyd or urethane-modified resin that incorporates orthobenzoylbenzoic acid and has a self-photopolymerization initiation function. Because of its poor dispersibility and wettability with pigments, it has poor emulsion fluidity and is currently unable to produce satisfactory printed matter when used in printing inks.

In addition, we have previously applied for a resin in which benzophenone having a carboxyl group is esterified into a copolymer resin of dicyclopentadiene and allyl alcohol (Japanese Patent Application No. 52-13).
8951) has improved the various drawbacks mentioned above, but since the molecular weight of the resin itself is low, the viscosity of the ink made using it is low! However, in high-speed printing, the ink transferability was still insufficient and the printing effect ratio was unsatisfactory. This is because the molecular weight and molecular weight distribution of the resin used in general oil-based inks is the cause of the large difference in ink transferability between rolls and to the printing material during high-speed printing such as rotary printing. It seems that there is a difference.

That is, for example, phenol resins used in general oil-based inks have an average molecular weight of 2,000 to 3,000. The average molecular weight of conventionally known prepolymers for ultraviolet curable inks is 1.
000 to 200, a dispersion index of 1.2 to 4 is common,
Ink that uses a resin with a high molecular weight changes stress in response to external forces and maintains the viscosity necessary for transition, whereas UV-curable ink that uses a resin with a small amount of high molecular weight changes This is believed to be due to the fact that during high-speed printing, the ink transferability deteriorates and the printing effect becomes insufficient.

In view of these points, the present inventors developed a high molecular weight resin having a photopolymerization initiation function, and arrived at the present invention.

That is, the present invention provides the following general formula (4): (wherein, R represents an organic residue having 1 to 3 carbon atoms,
n represents 0 or an integer of 1 to 6.

) and/or their Diels-Alder reaction products; (B) compounds having both a polymerizable double bond and a hydroxyl group in the same molecule; Resin (1) having a hydroxyl group obtained by reacting and (B) and/or the resin (
1) Resin with hydrogenated hydroxyl groups (■) Alkyd with excess hydroxyl group, which is used as part of the polyhydric alcohol component during alkyd resin production and is obtained by reacting with other polyhydric alcohols and carboxylic acids or their anhydrides. Resin (■)
An ultraviolet curable coating characterized by containing an alkyd resin (■) having a photopolymerization initiation function obtained by reacting a benzophenone derivative having a carboxyl group or a benzophenone derivative having a carboxyl group and an unsaturated carboxylic acid. It is a composition.

To describe the present invention in more detail, the resin (1) is a component (4) of a group consisting of cyclopentadiene, dicyclopentadiene, tricyclopentadiene, tetracyclopentadiene, and lower alkyl substituted products thereof having 1 to 3 carbon atoms. (meth)allyl alcohol, which is a compound having one or more selected from the following, and a polymerizable two-type bond and a hydroxyl group in the same molecule as component (B);
- Manufactured using one or more selected from the group of hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, butenediol, etc.

This resin (1) can be obtained by heating and reacting component (4) and component (B) at 150 to 350°C in the presence of a radical polymerization catalyst or without a catalyst, and if desired in the presence of a solvent such as xylene. It will be done. Components in the above reaction (
The molar ratio of A)/component (B) can be reacted at any ratio between 30/70 and 95/5, but for the purpose of the present invention, the molar ratio is between 40/60 and 95/5. 80/20
It is desirable that it be between. In the present invention, resin (1)
It is also possible to use a hydrogenated resin (■).

At this time, hydrogenation conditions must be carefully selected.Resin (1)
Only the carbon-carbon double bonds of the resin (1) must be hydrogenated without reducing the hydroxyl groups of the resin (1). Therefore, it is desirable to carry out hydrogenation using a noble metal catalyst such as platinum or palladium. When using these noble metal catalysts, hydrogenation is performed at room temperature to 250°C and normal pressure to 100K9.
It is preferable to carry out the hydrogenation under the condition of 1 cd without reducing the amount of hydroxyl groups. The degree of hydrogenation is usually
Hydrogenation of 40% or more, preferably 60% or more of the carbon-carbon double bonds possessed by the resin (1) significantly reduces the light shielding of the sensitizer and improves the photoreaction initiation effect (
■) is obtained. Resin (1) to resin (■) thus obtained are so-called resinous polyols, and most of them are considered to be diols with a molecular weight of 300 to 500.

In addition, resins (1) to (■) have good pigment dispersibility, and in the present invention, they are used as part of the polyhydric alcohol component during the production of alkyd resin to greatly improve pigment dispersibility. Moreover, even if it is a high-molecular-weight substance, it has good solubility and an alkyd resin that has good compatibility with the reactive solvent described below. (Resin (1) and resin (■)
is hereinafter abbreviated as DCPD polyol. ) In addition, other polyhydric alcohol components of the DCPD polyol in the production of hydroxyl-excessive alkyd include aliphatic polyols such as trimethylolpropane, glycerin, pentaerythritol, dipentaerythritol, tripentaerythritol, ethylene glycol, neopentyl glycol, One or more types selected from the group of glycols such as propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, and tripropylene glycol, and cyclic polyols such as trimethylolmelamine, benzoguanamine, and hexamethylolmelamine can be used. . In addition, the polycarboxylic acid components include aromatic polybasic acids represented by phthalic anhydride, isophthalic acid, and terephthalic acid, or their anhydrides, adipic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, hymic acid, and methyl phthalic acid. One or more types selected from acids, aliphatic polybasic acids represented by methylhymic acid, and their anhydrides can be used.

Among these, it is preferable to use an aliphatic polycarboxylic acid which has low ultraviolet absorption, since it is advantageous in that it blocks light from the aryl ketone and improves the photoreaction initiation effect of the resin (■) according to the present invention. In addition, hydroxyl group-excess alkyd resin (■
), linseed oil, rice bran oil,
Castor oil, dehydrated castor oil, coconut oil, tung oil or these fatty acids, chifurofuric acid, chifururic acid, chipurinic acid, lauric acid, myristic acid, palmitic acid, stearic acid,
Saturated fatty acids such as arachidic acid, oleic acid, linoleic acid,
One or more of unsaturated fatty acids such as linolenic acid, eleostearic acid, ricinolenic acid, rosin, hydrated rosin, disproportionated rosin, polymerized rosin, etc. per 10 parts of polyhydric alcohol and polybasic acid, They can be used together with an upper limit of 5 heel weight parts.

When the amount exceeds 5 parts, the molecular weight of the hydroxyl-excess alkyd resin decreases, and furthermore, the oxide film becomes plasticized and the solvent resistance deteriorates.

In addition, if necessary, methanol, ethanol,
It is also possible to use monohydric alcohols such as propanol, butanol, hexanol, octanol, benzyl alcohol, cyclohexanol, ethylene glycol monoalkyl ether, and oxo alcohol.

In the present invention, the hydroxyl group-excessive alkyd resin (■) is synthesized using 20 to 8 parts by weight of DCPD polyol, DCP
5 to 5 parts by weight of a polyhydric alcohol component other than D polyol,
10 to 5 parts by volume of polybasic acid, optionally the above-mentioned fatty oil,
Fatty acid, rosin, monohydric alkonol, etc. are added up to 5 parts by weight to a total of 100 parts by weight of polyol and polybasic acid, and these are charged into a four-bottle flask equipped with a stirrer and a condenser, and condensed at 150°C to 280'C. The reaction is carried out while removing the water produced during the reaction, and the oxidation value is 20 or less, preferably 20 or less, to obtain a hydroxyl-excessive alkyd resin (■).

During the above synthesis, the amount of DCPD polyol needs to be 20 to 80 parts by weight; if it is less than the weighted part, the polyester part will increase due to the reaction of polyhydric alcohol and polybasic acid other than DCPD polyol, As a result, the melting point increases and the solubility in mineral oil deteriorates. When printing ink, paint, etc. are made using the resin having the photopolymerization initiation function finally obtained, fluidity, gloss, etc. of printed matter deteriorate. In addition, when the amount of DCPD polyol exceeds 8 parts by weight, the crosslinkable part decreases, and the molecular weight of the hydroxyl-excessive alkyd resin (■) decreases, resulting in poor printability, setting properties, and drying properties when producing printing inks, etc. to degrade. In addition, during the above synthesis, in order to avoid polyester by-formation due to partial reaction of polybasic acid and polyhydric alcohol other than DCPD polyol, DCPD polyol and polybasic acid, fatty oil, fatty acid, rosin, etc. may be added as necessary. It is preferable to carry out an esterification reaction using a monohydric alcohol and then add a polyhydric alcohol other than the DCPD polyol.

In the present invention, the hydroxyl-excess alkyd resin (■) is produced as described above, and the excess hydroxyl amount of the hydroxyl-excess alkyd resin (■) is 120 to 12
The number of 6α offspring is 150-300.

The alkyd resin (■) having a photopolymerization initiation function according to the present invention (hereinafter abbreviated as the present invention resin) is a benzophenone derivative having a carboxyl group or an unsaturated carboxylic acid added to the hydroxyl-excess alkyd resin (■). Obtained by reaction. Such benzophenone derivatives having a carboxyl group include orthobenzoylbenzoic acid, parabenzoylbenzoic acid, carbonyl dibenzoic acid, carboxybenzoyl phthalic anhydride, benzophenone tetracarboxylic acid or its anhydride, dialkylamino-substituted benzoylbenzoic acid (alkyl The group is C1-C2)
etc. are used. In addition, the unsaturated carboxylic acid used with the benzophenone derivative having a carboxyl group is
These include acrylic acid, methacrylic acid, itaconic acid, sorpine acid, and crotonic acid.

Note that the benzophenone derivative having a carboxyl group and the unsaturated carboxylic acid can be reacted under normal esterification conditions without a catalyst or under a general acidic catalyst such as P-toluenesulfonic acid, sulfuric acid, or boric acid. When reacting the benzophenone derivative having a carboxyl group with the unsaturated carboxylic acid on the hydroxyl-excess alkyd resin (■), react the benzophenone derivative with a carboxyl group and the unsaturated carboxylic acid with the hydroxyl-excess alkyd resin (■) at the same time. There is a method in which a benzophenone derivative having a carboxyl group is reacted in advance, and then an unsaturated carboxylic acid is reacted with an excess of hydroxyl groups.

The resin (■) thus obtained is a resin that has a photopolymerization initiation function, and by using it, it is possible to obtain an ultraviolet curable coating composition for printing ink with good curability. .

In other words, conventionally, there are disadvantages such as volatility caused by excessive use of sensitizers, disadvantages such as migration and dispersibility caused by the properties of the resin itself, and especially in printing inks, problems caused by the decrease in ink viscosity. The disadvantages of printability, printing effect, swelling of the blanket, etc. can be overcome. The ultraviolet curable coating composition of the present invention consists of a resin (■) as a main component, and may also contain reactive solvents, sensitizers, pigments, other solvents, fillers, additives, etc. as necessary. It depends on what you used.

As the reactive solvent used in the present invention, one or more crosslinkable monomers or prepolymers having reactive double bonds that can be crosslinked by heating or irradiation with radiation such as ultraviolet rays or electron beams are used. can be used,
It is preferable to use 20 to 75 parts by weight per 25 to 7 parts of the alkyd resin (■) according to the present invention.

As such a reactive solvent, vinyl compounds are preferable, and (meth)acrylic acid derivatives are preferable from the viewpoint of reactivity, solubility, and low viscosity.

Examples of such acrylic acid derivatives include trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol (meth)acrylate, and 1,4-ptadiol (
Crosslinkable monomers having acrylic or methacrylic acid residues such as meth)acrylate, 1,6-hexanediol (meth)acrylate, alkyl (meth)acrylate (alkyl group having 1 to 18 carbon atoms), glycidyl (meth)acrylate, etc. can be mentioned. As the crosslinkable prepolymer, bisphenol A type epoxy resin with acrylic acid added, alkyd acrylate, urethane acrylate, etc. can be used.
It is desirable to use 25 to 70 parts by weight of the resin of the present invention (■) in an amount of 2 parts by weight or less. These reactive solvents are
Pigments can be uniformly dispersed, and in particular, curing can be performed quickly and easily. Although the composition of the present invention has a satisfactory curing rate even in the absence of commonly used photosensitizers, the curing rate can be further increased by adding a photosensitizer. In this way, photosensitizers include thioxanthone, xanthone and their halogen-substituted products as polycyclic carbonyls, benzophenone as aryl ketones, methyl 0-benzoylbenzoate,
1 from the group such as acetophenone, dialkylaminoaryl ketones such as 4●4″-bisdiethylaminobenzophenone, P-dimethylaminobenzoic acid, isoamyl, P-dimethylamino, acetophenone, etc., benzoyl, alkyl ether, etc. as acyloins; It can be used as a species or as a combination of two or more species.

When using the above-mentioned photosensitizer in the composition of the present invention, the usage range is from O to 7 parts by volume of the resin of the present invention (■).
It is desirable to use 20 parts by weight, but a sufficient curing rate can be obtained with m parts by weight or less.

Moreover, 0 to 6 parts of pigment can be used in the composition of the present invention.

Furthermore, other organic solvents, fillers, additives, etc. can be used as necessary. However, since the composition of the present invention is cured immediately by ultraviolet irradiation at room temperature in the air without the use of a commonly used organic solvent, it is difficult to cure the composition using solvent vapor like a composition using a large amount of a conventional organic solvent. No pollution problems will occur due to the emission of In addition, it has the advantage of good adhesion to printing substrates and flexibility of the cured film, making it highly processable. This will be explained below using examples. Parts in the examples indicate parts by weight. Example 1 132 parts of dicyclopentadiene with a purity of 97%, 58 parts of allyl alcohol, and 110 parts of commercially available mixed xylene were charged into an autoclave equipped with a stirrer, and reacted at a temperature of 260°C for 5 hours.

After the reaction is completed, the autoclave is cooled and the contents are distilled to remove end-reacted monomers, low polymers, and xylene.
15? Resin (1)-1 was obtained. This resin (1)-
11 parts were dissolved in commercially available mixed xylene, 1 part of palladium carbon (1) 5% PdC standard product manufactured by Engelhard Co., Ltd. with a palladium concentration of 5% was added, and the hydrogen pressure was 30k91c.
A hydrogenation reaction was carried out at 1150° C. for 1 hour, and the solvent was distilled off to obtain a water-added resin (■)-1. The properties of Resin (1)-1 and Resin (■)-1 are as follows.

Next, 145 parts of resin (1), 29 parts of phthalic anhydride, and 26 parts of trimethylolpropane were charged into 4 flasks equipped with a stirrer and a condenser directly connected to the separation tube, and reacted at 240'C for 7.5 hours under a N2 gas stream to determine the acid value. 7.8 hydroxyl group-excess alkyd (■)-1 was obtained.

476 parts of this hydroxyl-excess alkyd and 524 parts of O-benzoylbenzoic acid were charged into four flasks equipped with a stirrer and a condenser directly connected to the separation tube, and refluxed with commercially available mixed xylene.
After reacting for 7 hours at 40'C, the acid value reached 19.0, and after xylene was removed, a resin (■) with an acid value of 18.7 and a melting point of 83°C was obtained.
I got 1. Example 2 Resin (■)-1 was mixed with 45% of the acid TH (manufactured by New Japan Chemical Co., Ltd.: Tetrahydrofuric anhydride) 29DI! f) was placed in a 4-hole flask equipped with a condenser directly connected to a separate tube and a stirrer, and heated to 150°C while blowing N2 gas under reflux of commercially available mixed xylene. react for 26 hours, trimethylolpropane
(2) was added and reacted at 200°C for 5 hours to obtain an acid value of 8.
A hydroxyl-excess alkyd (■) of No. 7 was obtained.

475 parts of this alkyd resin and 525 parts of O-benzoylbenzoic acid were charged into a four-bottle flask equipped with a stirrer and a condenser directly connected to a separation tube, and reacted at 200°C for 5 hours while blowing N2 gas under reflux of a commercially available mixed xylene, resulting in an acid value of 19. .2
Then, xylene was removed to obtain resin (■)-2 having an acid value of 19.01 and a melting point of 78°C. Example 3 Hydroxyl-excess alkyd obtained in Example 2 (■)-2650
fff, 100 parts of HN22OO (manufactured by E1 Ritsu Kasei: latrahydromethylphthalic anhydride), 2 (sub) parts of 0-benzoylbenzoic acid, and a stirrer, 4 with a condenser directly connected to the separation tube.
Pour into a double flask and add N2 under reflux of commercially available mixed xylene.
230℃ while blowing gas 6. Residual value after time reaction: 18
．． 9 and xylene was removed to obtain resin (■)-3 having an acid value of 18.2 and a melting point of 85°C.

Example 4 143 parts of resin (■), w parts of water-added rosin, 23.5 parts of adipic acid, and 24 parts of pentaerythritol were reacted in the same manner as in Example 1 to form a hydroxyl-excess alkyd with an acid value of 10.6. Resin (■)-4 was obtained, and this alkyd resin 48
Department, Versatime 216 (Japan General Mills Chemical Co., Ltd.:
Linseed oil fatty acid dimer) 20 parts and O-benzoylbenzoic acid 3? Resin (■)-4 having an acid value of 17.5 and a melting point of 5rc was obtained in the same manner as in Examples 1 to 3.

Example 5 Hydroxyl-excess alkyd resin obtained in Example 2 (■)-27
42 parts of O-benzoylbenzoic acid, 80 parts of O-benzoylbenzoic acid, 1 part of hydroquinone, and 1 part of P-toluenesulfonic acid were charged into 4 flasks equipped with a stirrer and a condenser directly connected to the separation tube, and in a mixed solvent of methyl isobutyl ketone/cyclohexane 1/3. 178 parts of acrylic acid was dropped at 80°C over 3 hours,
Thereafter, the reaction was carried out at 100°C for 9 hours to give an acid value of 17.9, and the mixed solvent was . After removal, a resin (■)-5 having an acid value of 16.7 and a balsamic state at room temperature was obtained.

Example 6 750 parts of the hydroxyl-excess alkyd resin obtained in Example 2 and O
-Benzoylbenzoic acid 8(2), P-toluene. The sulfonic acid solution was charged into four flasks equipped with a stirrer and a condenser directly connected to a separation tube, and reacted at 120°C for 6 hours under a 1/3 mixed solvent of methyl isobutyl ketone/cyclohexane.
When the acid value reached 5.2, the mixture was cooled to 80°C, 1 part of hydroquinone was added, and 178 parts of acrylic acid was added over 3 hours.Then, the mixture was reacted at 100°C for 9 hours, and the acid value was adjusted to 15.4. , after removing the mixed solvent, the acid value was 15. A wet balsam-like resin (■)-6 was obtained.

Example 7 Hydroxyl-excess alkyd (■)-2777 obtained in Example 2
1 part, 3.3"4.4"-benzophenone tetracarboxylic dianhydride part, and 1B part of acrylic acid were reacted in the same manner as in Example 5 to obtain an acid value of 18.2 and a melting point of 74.
C. Resin (■)-7 was obtained.

Example 8) These resins having a photopolymerization initiation function (■
)'s use in printing inks has declined at the following rates:

An ink vehicle was prepared with 40 parts of each resin having a photopolymerization initiation function and phenylene diglycol diacrylate 6B, 60 parts of each ink vehicle, and carmine 6B.
Inks 1 to 7 were obtained by kneading 20 parts of H (manufactured by Toyo Ink), 2 parts of P-dimethylaminoacetophenone, and 18 parts of dipentaerythritol hexaacrylate using a three-roll roll.

Example 9 Furthermore, 2 parts of methyl O-benzoylbenzoate was kneaded into 95 parts of each of the inks 1 to 7 obtained in Example 8 using three rolls to obtain Inks 8 to 14.

Comparative Example 1 Resin (■) - 178 parts, P-toluenesulfonic acid 1 part, hydroquinone 0.1 part, cyclohexane/M
15 parts of IBK = 2/1 mixed solvent were charged into four Lof flasks equipped with a stirrer and a condenser directly connected to a separation tube, and n parts of acrylic acid were added at 80°C, and the mixture was reacted at 100'C for 7.5 hours.
Thereafter, the cyclohexane/MIBK mixed solution was removed to obtain curable resin (ratio)-1.

Comparative Example 2 Resin (■) - 1742 parts, 0-benzoylbenzoic acid 8 parts, acrylic acid 17.8 parts, hydroquinone 0.
Resin (ratio)-2 having a photopolymerization initiation function was obtained in the same manner as in Example 5 using 1 part of P-toluenesulfonic acid and 2 parts of P-toluenesulfonic acid under a MIBK/cyclohexane mixed solution.

Using these resins, ink 15N1 was prepared in the same manner as in Example 8.
Inks 17 and 6 were prepared in the same manner as in Example 9.
I got 18.

The evaluation results of the ink are as follows.

Claims (1)

[Claims] 1(A) The following general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R is an organic residue having 1 to 3 carbon atoms, and n is 0 or an integer of 1 to 6 (B) a compound having both a polymerizable double bond and a hydroxyl group in the same molecule, Resin (I) having a hydroxyl group obtained by reacting the above (A) and (B) and/or a resin (II) having a hydroxyl group obtained by hydrogenating the resin (I) Polyhydric resin used in the production of alkyd resin A benzophenone derivative having a carboxyl group, or a benzophenone derivative having a carboxyl group and An ultraviolet curable coating composition characterized by containing an alkyd resin (IV) having a photopolymerization initiation function obtained by reacting an unsaturated carboxylic acid. 2. The composition according to claim 1, which comprises resin (IV) and a reactive solvent. 3 20-80 parts by weight of resin (IV), 5-50 parts by weight of reactive solvent
3. The composition according to claim 1, wherein the composition comprises 0 to 20 parts by weight of a sensitizer, and 0 to 60 parts by weight of a pigment.