JPS63152603A - Photocurable resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition, consisting of an acryloyl or methacryloyl group-containing polymer or oligomer, white pigment and compound capable of generating radicals and photocurable in a short time even in the presence of a large amount of white pigment. CONSTITUTION:A composition consisting of (A) a polymer or oligomer, having one or more (meth)acryloyl groups in one molecule, e.g. a compound, expressed by formula III and obtained by reacting a polymer, expressed by formula I and having hydroxyl group with an unsaturated isocyanate expressed by formula II, etc., (B) a white pigment, e.g. titanium white, zinc flower, etc., (C) a compound, having <=60 deg.C decomposition temperature at 10hr half life and capable of generating radicals, e.g. 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), etc. This composition is used as light-colored coated materials based on pure white or white in the field of coating materials, inks, etc.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a photocurable resin composition, particularly a resin composition that is photocurable even if it contains a white pigment such as titanium white, and is mainly used for coatings, In the field of coatings such as ink,
It is used for pure white or light-colored painted objects based on white.

[Conventional technology]

In a photocurable system, when using a paint that uses a large amount of white pigment such as titanium white, for example 10% or more, the ultraviolet absorption range of titanium white is the decomposition wavelength of the initiator used for photocuring. Due to the overlap with the area, curing was severely inhibited. In order to prevent this, a photocuring system that uses a thioxanthone-based initiator and an amine-based sensitizer in combination has been put into practical use.

However, although this system is certainly effective when the titanium white concentration is not high, unfortunately, when the amount of sensitizer that can be cured is high, it becomes yellowish and has the disadvantage that a pure white coating cannot be obtained. .

In recent years, West German BASF has reported that when acylophosphine oxide is used, photocuring is possible even when titanium white is mixed (for example, Japanese Patent Publication No. 60-804
7 and JP-A-55-15471). Compared to previous initiators, this type of initiator was superior in whitening and curability of coating films containing titanium white, and improvements were observed.

However, it has become clear that when titanium white is mixed at a high concentration of titanium white, for example, at a concentration of 20 parts or more, curing is significantly inhibited and sufficient curability cannot be obtained.

[Problem that the invention seeks to solve]

The present invention uses a large amount of white pigment such as titanium white (for example, 10
% or more) and which can photocure in a short time a (meth)acryloyl group-containing polymer or olicomer that cannot be cured or is only insufficiently cured with general photoinitiators. is to provide.

[Means for solving problems]

That is, the photocurable resin composition of the present invention comprises (A) a curable polymer or oligomer having one or more (meth)acryloyl groups in one molecule; CB) a white pigment; and (C) a half-life of 10 hours. It consists of using together three radical-generating compounds with a decomposition temperature of 60°C or lower, especially azo compounds and organic peroxides with a decomposition temperature of 60°C or lower with a half-life of 10 hours. The present invention was completed based on the discovery that by using a compound, photocuring is possible in a short time even in the presence of a large amount of white pigment.

[Effect]

In the present invention, it is possible to generate radicals whose decomposition temperature with a half-life of 10 hours (hereinafter simply referred to as half-life temperature) is 60°C or less, and whose performance is insufficient to heat cure the (meth)acryloyl group-containing oligomer or polymer within a short time. For some reason, when used in combination with a white pigment, a polymer or oligomer having a (meth)acryloyl group can be photocured in a short period of time. Although the details of the reason are not known, it is presumed that a synergistic effect is exerted because the compound capable of generating radicals is photodecomposed by ultraviolet irradiation and thermally decomposed by the heat generated from the same device.

Compounds capable of generating radicals and having a half-life temperature of 60° C. or lower include azo compounds and organic peroxides. As an azo compound, 2,2'-azobis(4-methoxy-2,4
-trimethylvaleronitrile) (half-life temperature (same below)
Typical examples include 2,2'-azobis(2,4-dimethylvaleronitrile) (51°C).

Further suitable examples of organic peroxides include peroxyesters and g-oxycargonates.

For example:

Acetylcyclohexylsulfonyl-oxide (half-life temperature 26.5°C), isobutyryl-J? -oxide (32,5℃), cumyl peroxyneodecanoate (
36,6°C), diisopropyl peroxynocarbonate (40,5°C), diallylnozo-oxynocarbonate (38,8°C), di-n-propyl peroxydicarbonate (40,5°C), cimilistil. zo-oxydicarbonate (40.9°C), no(2-ethoxyethyl)-ri-oxydicarbonate (43.4°C), di(methoxyisopropyl)peroxydicarbonate (43°C)
, 4°C), di(2ethylhexyl) peroxycarbonate (43,5°C), t-hexylno-R-oxyneohexanoate (44,7°C), t-butylperoxyneohexanoate (44,7°C), 46,5℃), di(3methyl-3
-methoxybutyl)peroxydicargone) (46,
5'c), tert-butylmi-4-oxyneohexanoate (46.5°C), t-hexylno-oxyneohexanoate (51.3°C), t-butylperoxyneohexanoate (51.3°C), 539C), t-hexylmi 4
-Oxyvivalate (53,2℃), t-butyl y-
Oxypivalate (55℃), bis(4-1-butylcyclohexyl) and monooxydicate (
44℃).

Practically speaking, if we consider the storage stability of the mixture, the speed of curing, the handling properties of organic peroxides at room temperature, peroxycarbonate-based materials, especially bis(4-t-butylcyclohexyl) peroxycarbonate ( A representative example of this is available from Kayaku Nouri Co., Ltd. under the trade name Parryoku Donox+16.

Of course, the present invention is not limited to these representative examples.

The amount used is 0.03 to 5 parts by weight, preferably 0.1 to 2 parts by weight per 100 parts by weight of the (meth)acryloyl group-containing polymer or oligomer. If the amount is less than this range, photocuring will be difficult, and if the amount is more than this range, the effect will be poor and foaming will occur, which is not preferred.

High-temperature decomposable radical-generating compounds whose half-life temperature exceeds 60° C., such as benzoyl peroxide and azobisisobutyronitrile, which are commonly used as radical polymerization catalysts, have poor effects.

The curable polymer or oligomer having one or more (meth)acryloyl groups in the molecule used in the present invention has a molecular weight of 200. Preferably 500 or more, 200,000 preferably 100,00
Typical examples are as follows.

(a) Vinyl ester resin (epoxy-(meth)acrylate) An oligomer obtained by reacting an epoxy resin and (meth)acrylic acid such that the epoxy groups and carboxyl groups are substantially equimolar. be.

Typical epoxy resins include bisphenol diglycidyl ether type, Noblak's polyglycidyl ether type, polybasic acid polyglycidyl ester type, and epoxy resins obtained by oxidizing intramolecular double bonds with peracetic acid. Can be mentioned.

(b) Polyurethane - (meth)acrylate Synthesized using an unsaturated monoalcohol that shares a hydroxyl group and a (meth)acryloyl group in the molecule, a polyvalent isocyanate compound, and, if necessary, a polyether polyol and a polyester polyol. It is an oligomer that is

Examples of unsaturated monoalcohols include 2-hydroxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl acrylate, and 2-hydroxyethyl acrylate.
-Hydroxyethyl acrylate and 2-hydroxyethyl methacrylate.

Examples of polyvalent incyanate compounds include tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1.5-naphthylene diisocyanate, and polyisocyanate of polyhydric phenol. .

(c) Polyester-(meth)acrylate An oligomer synthesized by condensation of (meth)acrylic acid and any polybasic acid or polyhydric alcohol. It can also be synthesized by a transesterification method using (meth)acrylic acid ester, or by reacting glycisol (meth)acrylate with a polyester containing a terminal carboxyl group.

The polybasic acids and polyhydric alcohols used are not particularly limited, and include maleic acid, fumaric acid, terephthalic acid, isophthalic acid, ethylene glycol, propylene gellicol, butaneol, and neopentyl, which are commonly used as raw materials for polyester resins. Glycol is a typical example.

2) Spiroacetal - (meth)acrylate A spiroacetal structure is obtained in the molecular structure obtained by reacting an unsaturated monoalcohol that shares a hydroxyl group and a (meth)acryloyl group in the molecule with diarylidene pentaerythritol. It is an oligomer with

As the unsaturated monoalcohol, the same one as mentioned in Naka) is used.

The (meth)acrylate oligomers (a) to (a) above may be used as they are, or may be used in combination with a (meth)acrylate monomer such as methyl methacrylate.

It is desirable that the (meth)acrylate oligomer has a molecular weight of 200 or more. If the molecular weight is less than 200, the physical properties of the cured film will be poor, which is not preferable.

(e) Polymers having (meth)acryloyl groups in side chains There are several synthesis methods and types, but in general, the following polymerizable monomer (1) and (meth)acryloyl groups are introduced into the monomers. functional groups (e.g. acid anhydride groups,
A polymerizable monomer (11) having a carboxylic acid group, a hydroxyl group, an epoxy group) and a polymerizable double bond, and a reactive group (for example, a hydroxyl group, an epoxy group, an NCO group) with the functional group of the monomer (11). ) and a compound (iii) having a (meth)acryloyl group.

The monomer (1) forming part of the polymer main chain does not need to be particularly limited, but includes, for example, styrene, vinyltoluene, chlorostyrene, acrylic esters, methacrylic esters, acrylonitrile, vinyl chloride,
Typical examples include vinylidene chloride, vinylpyrrolidone, and vinyl acetate.

A monomer (11) that forms part of the polymer main chain and has a functional group for introducing a side chain (meth)acI
) are representative examples of acrylic acid, methacrylic acid; maleic anhydride, itaconic anhydride; unsaturated monoalcohols mentioned in (b); methylol acrylamide, glycytyl (meth)acrylate, and epoxy resin mono(meth)acrylate. It is true.

Compound (iii) which introduces a (meth)acryloyl group into a side chain into a polymer is an unsaturated compound described in the above-mentioned intermediate) which reacts with an acid anhydride group in the polymer to introduce a (meth)acryloyl group into a side chain. Alcohols; unsaturated epoxy compounds that react with carboxyl groups in side chains of polymers to introduce (meth)acryloyl groups, such as glycidyl (meth)acrylate, especially glycidyl methacrylate, mono(meth)acrylates of epoxy resins: side chains of polymers; 0 ■
Examples include inocyanate ethyl methacrylate, unsaturated isocyanates, etc., which react with groups. The above-mentioned unsaturated incyanate can be obtained by the reaction of the unsaturated monoalcohol described in (b) with a polyhydric incyanate.

In this case, it is necessary to react 1 mol or more of unsaturated monoalcohol per 1 mol of polyvalent isocyanate. For example, 1 mol of unsaturated alcohol per mol of diisocyanate.
．． It is necessary to react in a range of 1 to 1.8 moles to leave NGO groups, and these remaining NCO groups react with the hydroxyl groups of the polymer main chain obtained from monomers (1) and (11). used for.

Polymer (A) having (meth)acryloyl group in the side chain
A typical example of is produced as follows: (To) A polymer having all acid anhydride structures in its structure is reacted with an alcohol having a (meth)acryloyl group: A carboxyl group is added to the fiber structure. to polymers with (meta)
Reacting an epoxy compound having an acryloyl group: Reacting a polymer having a hydroxyl group in the final structure with an unsaturated incyanato compound containing an isocyanate group and a (meth)acryloyl group in the molecule: The above water Among the side polymers, a polymer having a (meth)acryloyl group in the polymer side chain via a urethane bond, which is obtained by reacting a polymer having a hydroxyl group with an unsaturated incyanate, is most preferred.

Polymers having (meth)acryloyl groups in their side chains have high molecular weights (approximately 10,000 to 200,000) and are therefore usually used in combination with solvents or monomers.

The white pigments used in the present invention are commonly commercially available products such as titanium white, zinc white, calcium carbonate, and magnesia, and two or more types can be used in combination.

Among these white pigments, titanium white, which is rutile-type or anatase-type titanium dioxide, is most suitable. The amount used is preferably in the range of 5 to 100 parts by weight per 100 parts by weight of component (A). If it is less than 5 parts by weight, it cannot be photocured using conventional sensitizers such as acylophosphine oxide, dialkyl benzyl ketal, etc., and the whiteness is poor.
If the amount is more than 100 parts by weight, it becomes meaningless in terms of coloring properties, and is therefore not preferred.

The photocurable resin composition of the present invention is coated or cast onto an object and then exposed to an incandescent lamp. It can be easily cured using a mercury lamp, an infrared lamp, an ultraviolet fluorescent lamp, a carbon arc, a xenon lamp, etc.

〔Example〕

Next, examples will be shown below to help understand the present invention.

Example 1 (1) Synthesis of vinyl ester resin (A) In a 117-4 rubble flask equipped with a stirrer, a reflux condenser, and a thermometer, Dow's DER-332 was added as an epoxy resin.
3501, acrylic acid 1419, trimethylbenzylammonium chloride 1.5y, and methylhydroquinone 0115g were charged and heated to 120 to 130°C for 3 hours.The acid value became 14.1, so heating was stopped.
206g of trimethylolguronogu citria acrylate,
Add 200I of phenoxyethyl acrylate and add vinyl ester resin (4) to Hazen color number 350 and viscosity approximately 1.
Obtained with 4 poise.

(2) Synthesis of polyurethane-acrylate (B) Equipped with a stirrer, reflux condenser, gas introduction tube, and thermometer.
2-hydroxyethyl acrylate 2321 phenoxyethyl acrylate 60
0F, 2,4-tolylene diisocyanate 348. When F was charged and reacted for 3 hours at 60°C in a stream of dry air, infrared analysis determined that 57 ('6) of the incyanato group had reacted.

Next, 220 g of dipropylene glycol, 2 g of dibutyltin dilaurate, and 0.2 g of parapenizoquinone were added, and the mixture was further reacted at 60° C. for 5 hours. As a result of infrared analysis, it was confirmed that the free incyanato groups had completely disappeared.

The obtained polyurethane-acrylate (B) was pale reddish brown and had a viscosity of 29 poise.

(3) Synthesis of polyester acrylate (Q) Glycidyl methacrylate 4280,1
Phthalic anhydride 296g, neopentyl glycol 104
I, trimethylbenzylammonium chloride 2F,
After charging 0.5 g of hydroquinone and reacting at 130 to 135°C for 3 hours, the acid value became 9.1, so the reaction was stopped, and 420 g of cresol ethyl acrylate was added.
Polyester acrylate (Q is Hazen color number 450,
A viscosity of 11.4 poise was obtained.

(4) Synthesis of spiroacetal acrylate (D) Into an 11-piece scrambled flask equipped with a stirrer, a reflux condenser, and a thermometer, 222 g of diarylidene pentaerythricite and 232 J of 2-hydroxyethyl acrylate were added.
i', prepare 4.5 g of #radluenesulfonic acid, 6
After reacting at 0 to 65° C. for 10 hours, infrared analysis revealed that the unsaturated bonds of diarylidene pentaerythritite disappeared.

After adding 5 g of triethylamine to remove the odor from free acrolein, it was washed three times with 300 g of 1% sodium carbonate solution and then with 200.9 g of distilled water.

Next, change the reflux condenser to a fractionation condenser, and
The water was removed by heating to 65-70° C. at ~12 aud Hg.

trimethylolguronogcitriacrylate 400I,
Added 0.1.9 of methylhydroquinone, spiroacecool acrylate (D) has a Hazen color number of 300 and a viscosity of 5.47 f! Obtained with is.

(5) Polymer with methacryloyl group in the side chain (E
) 104g of styrene, 2-
Hydroxyethyl methacrylate 26 (9, isobutyl methacrylate 115I, tertiary dodecyl mercaptan 2.4F, azobisisobutyronitrile 2.4F
, 240 g of methyl ethyl ketone, 65-70
Polymerization was carried out at ℃ for 12 hours in a nitrogen stream.

On the way, every 4 hours, add azobisisobutyronitrile twice at 1.2! Added one by one.

0.2 I of hydroquinone was added to stop the polymerization.

The polymerization rate was 91%. As a result of GPC analysis, a polymer containing a side chain hydroxyl group was obtained, which had a peak at 127,000 molecules.

In addition, 31.9 g of incyanato ethyl methacrylate and 1 g of dibutyltin dilaurate from Dow Chemical Company, USA.
was added and reacted at 75 to 80°C for 6 hours, and as a result of infrared analysis, the absorption of isocyanate groups completely disappeared.

Change the reflux condenser to a fractionation condenser, distill about 100 CC of methyl ethyl ketone at normal pressure, add 330 g of phenoxyethyl acrylate,
The remaining amount of methyl ethyl ketone was determined by gas chromatographic analysis to be 0.
It was distilled until it became 2 (%) or less.

The obtained polymer having a methacryloyl group in its side chain (
E) (monomer solution) was obtained with a color number of 200 and a viscosity of 21.7 poise.

To 100 parts of each of the resins mentioned above, 80 parts of titanium white, [2,2
-Azobis(4-methoxy-2,4-dimethylvaleronitrile)] (Product name: V-700.3, manufactured by Wako Pure Chemical Industries, Ltd.)
The mixture was kneaded with three rolls to obtain paint resin samples (a) to (
e).

Separately, as a comparative example, in place of ■-70, 2 parts of 2,2-simethoxy-2-phenyl-acetophenone (Irgacure≠651 manufactured by Ciba), dimethylaminoethanol-#
A system was prepared in which 0.5 part was added to 100 parts of each of the resins described above.

What about the samples (a) to (e) mentioned above? Painted with a percoater to a thickness of 100μ on a Ndellite steel plate to a thickness of 50μ.
A μ polyester film was attached.

The temperature of the plate was kept constant at 30 to 35°C. Set this to output 50
The sample was passed through a kW ultraviolet irradiation device at a speed of 15α and 2W under the lamp. The required irradiation time was 1 minute.

The temperature of the coated plate leaving the irradiation device was in the range of 60 to 65°C. The results obtained after excluding the film were as shown in Table 1, and only the system containing V-70 was completely cured and was suitable for practical use.

Similarly, add 0.3 parts of V-70 to sample (A) and add 1
A Ndellite steel plate with a film attached to it that had been painted to a thickness of 0.00 μ was left in a room at 60°C, but it did not harden at the gluing stage even after 30 minutes, which was definitely different from photo-curing. It was.

Example 2 Polymer (III) having (meth)acryloyl group in side chain
Synthesis of unsaturated epoxy resin (a) In a 1-7 paraple flask equipped with a stirrer, a thermometer with a gas inlet tube, a reflux condenser +, and an I lower funnel, Epicoat 827 from Mitsubishi Yuka-Ciel was added as an epoxy resin. 360
Ii (1-E-nyl), methacrylic acid 43N (0.5 mol), hensyldimethylamine 1.2 g, aJ? When labenzoquinone o and osy were charged and reacted for 3 hours under air blowing conditions at 120-130°C, an unsaturated epoxy resin (2) was obtained in the form of pale reddish brown silazo with almost no acid value.

The resin (,) is calculated as a mixture of the following formula CI) is 223II and the formula ([] is a free epoxy resin 180.9).

Synthesis of side chain epoxy resin (b) Into the same apparatus as above, methyl ethyl ketone 2509, unsaturated epoxy resin (a) 173 Jil (0.2 mol), styrene 1001, azobisisobutyronitrile 3.
5y was charged, and styrene 871 (accounting amount of styrene: 1.8 mol) was added dropwise at 75° C. in a nitrogen stream.

After 6 hours, 2 g of azobisisobutyronitrile was further added, and I'ij1 polymerization was further carried out at 10 o'clock.

When the polymerization rate reached 96%, hydroquinone 0.22
was added to stop the polymerization.

A solution of the side chain epoxy resin (b) in methyl ethyl ketone (solid content: 40 cycles) was obtained in the form of a pale yellowish brown liquid.

As a result of GPC analysis, it was confirmed that it was a mixture of a polymer having a peak at a molecular weight of about 50,000 and an unreacted epoxy resin.

Synthesis of side chain unsaturated bond type resin (F) To the methyl ethyl ketone melt of the side chain epoxy resin (b) described above, 52 g (0.60 mol) of methacrylic, triphenylphosphine o, s! After reacting for 16 hours at the boiling point of methyl ethyl ketone, the acid value was 10.4, so 620 g of phenoxyethyl acrylate was added and heated under reduced pressure of 400 to 450 mHH to remove methyl ethyl ketone.

After about 6 hours, gas chromatography analysis showed that methyl ethyl ketone had a coefficient of 0.3, so heating was completely stopped, and the side chain unsaturated viscous resin (T) was yellowish brown and had a viscosity of 8.5.
Obtained with Poise.

After adding and kneading 50 parts of titanium white and 50 parts of calcium carbonate to the resin (No. 100 fs'6), the liquid was divided into two parts, and -100 was C2,2'-azobis(2゜4-dimethylvaleronitrile)] (V-65 manufactured by Wamoto Nawa Yakuko Kuri (Company)
This was used as a sample.

Separately, on the other side, azobisisobutyronitrile (65
°C) -<o, 5 N was added, and this was used as a sample (g).

Both were coated with a percoater to a thickness of 70μ on a slate board with a board temperature of 30°C and a thickness of 5 nV/rn.
It was passed at a speed of tt f 1 m15+.

It takes about 100 seconds to pass, and the temperature when leaving the irradiation machine is 65
The temperature was ~70°C.

The blood film using the sample was completely cured, and its physical properties were as shown in Table 2.

A colleague left the 2nd sample in a thermostat at 65°C, but it
After a few minutes had elapsed, the curing was cured, and an essential difference from photocuring was observed.

Example 3 100 parts of the vinyl ester resin (5) produced in Example 1, 100 parts of titanium white, and bis(4-t-butylcyclohexyl)tsuku-oxydicarbonate (trade name: Parrydox+16, manufactured by Kayaku Nouri Co., Ltd.) One part was uniformly kneaded with a roll, and after coating it to a thickness of 100μ on a Sonderite steel plate at a temperature of 30°C, it was heated at 20crn under an ultraviolet irradiation device with an output of 50kW.
Passed at m10.

The time it took to pass was 100 seconds. The coating temperature when it came out of the irradiation machine was 67℃, and the coating was completely cured.
The hardness at 23° C. was 3 to 4H, the cross-cut adhesion was acceptable, and the goblin test was 100/100.

When a similar painted board was left in a constant temperature bath at 60-65℃, 3
Although gluing of the coating was observed after 0 minutes, it was only to the extent that it could be scratched with a fingernail (2B or less), and it required further curing at 80° C. for 1 hour to reach the same hardness as photocuring.

Example 4 Spiroacetal-acrylate produced in Example 1 (
100 parts of D), 90 parts of titanium white, and (1)
As sample (a), t-butyl peroxyvivalate (NOF ■) g-butyl pv) (II) Sample (as a male, t-butyl A'-oxyneodecanoate (perbutyl ND) (iii) As sample (2), 165 parts of dimyristyl peroxydicargonate (Perloil MSP) were added to each sample and kneaded with three rolls to form a uniform paste.

The surface of a paper-based phenolic resin laminate with a thickness of 1.6 m and 1 m and a size of 300 x 300 m/m was polished with +300 abrasive paper. As an air-curing urethane primer, use 20-25% of Vinylow/I/+1300X manufactured by Showa Kobunshi Co., Ltd.
I painted it so that it became μ and left it overnight.

After coating the samples (G) to () to a thickness of approximately 200μ, a polyethylene film with a thickness of 50μ was adhered, and after squeezing with a roll to make a coating film with a thickness of approximately 100μ, ultraviolet rays with an output of 50 kW were applied. Twenty subs were passed under the irradiation device at a speed of one part.

The plate temperature before entering the irradiation machine is 34℃, and the temperature immediately after leaving it is 6℃.
The temperature was 8°C.

All of the coating films were completely cured, and the physical properties of the coating films after peeling off the films were as shown in Table 3.

Table 3: Hardness of bread adhesion test Appearance sample (E)
3H100/100 Uniformly white sample (1 force
3H100/100 Same as above sample-) 3H
100/100 Same as above [Effect of the invention] The photocurable composition of the present invention has white skin and hiding power that are difficult to achieve with conventional photocurable resins, regardless of the type or color of the object to be coated. It is possible to form a complete photocurable coating, making it extremely useful in the field of coatings such as paints and inks.

Claims (1)

Scope of Claims: (A) a curable polymer or oligomer having one or more (meth)acryloyl groups in one molecule, (B) a white pigment, and (C) a decomposition temperature of 60°C with a half-life of 10 hours. A photocurable resin composition characterized in that the following three compounds capable of generating radicals are used in combination.