JPH0780990B2 - Method for producing ultraviolet or radiation curable resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Purpose of the invention Industrial field of application The present invention is an ultraviolet or radiation curable type which is useful for paints, inks, conductive paints and the like that use radiation such as ultraviolet rays or electron beams as a curing means. The present invention relates to a method for producing a resin composition, wherein the composition according to the present invention has excellent properties of a cured product coating film such as mechanical properties and transparency, and has excellent properties of adhesion to metal and metal oxide and dispersibility. I have.

BACKGROUND ART Urethane (meth) acrylates have various chemical structures depending on the combination of raw materials for producing them, that is, various alcohols, isocyanate compounds and hydroxyl group-containing (meth) acrylates, some of which are already commercially available. Are used for various purposes. On the other hand, the technique of curing resin by radiation such as ultraviolet rays and electron beams continues to develop as a technique that replaces the conventional heat curing from the viewpoints of improving line speed, resource saving, and environmental measures. Development of production technology using radiation curing for paints, inks, conductive paints, etc. has been widely conducted.
It is hard to say that we have reached a satisfactory level. A major cause of this is that the urethane (meth) acrylate used for these does not yet have excellent cured coating film properties and good adhesion and dispersibility to metals and metal oxides. .

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As described above, various urethane (meth) acrylates have been used in the past, but they have excellent cured film characteristics, and have excellent adhesion and dispersibility to metals and metal oxides. (Meth) acrylate is not yet known.
From such a situation, the present invention provides a urethane (meth) having excellent mechanical properties, transparency, adhesion to a metal substrate, and excellent adhesion and dispersibility to metals and metal oxides. ) It is intended to provide a method for producing an ultraviolet or radiation curable resin composition containing an acrylate as a curable component.

(B) Structure of the invention Means for solving the problems As a constant problem in the fields of paints, inks, conductive paints, etc., the mechanical properties, surface gloss, transparency, and base of the binder resin used for these are It has cured film properties such as adhesion to materials. For ultraviolet or radiation curable resins, urethane (meth) acrylate is often used for these applications because of the toughness of the cured coating film. However,
Urethane (meth) acrylate has the drawback of not having sufficient adhesion to metal substrates, as well as adhesion and dispersion to pigments such as metals and metal oxides required for binder resins of inks and conductive paints. The sex is not enough.
In order to improve dispersibility in metals and metal oxides, improvement in terms of molecular weight and molecular structure and addition of a dispersant having a polar group are often carried out, but the former method requires the binder resin. However, the latter means is not preferable because there is a change with time due to migration of the dispersant after curing to the surface.

As a result of intensive studies by the present inventors, an ultraviolet or radiation resin composition comprising a urethane (meth) acrylate having a carboxyl group in the molecule has excellent mechanical properties, transparency, surface gloss, and metal base material. It was found that the cured coating film characteristics such as the adhesiveness and the excellent adhesiveness and dispersibility to metal and metal oxide are combined.

Regarding the urethane (meth) acrylate having a carboxyl group in the molecule, JP-A-61-18610 discloses 2,
What was produced by reacting a polyhydric alcohol containing 2- (dihydroxymethyl) propionic acid and a polyvalent isocyanate all at once to produce a terminal isocyanate urethane oligomer, and reacting this with a hydroxyl group-containing (meth) acrylate Are known. According to this production method or the production method using 2,2- (dihydroxymethyl) propionic acid as a raw material instead of 2,2- (dihydroxymethyl) propionic acid, a compound (I) having an average structure shown below is produced.

R- (M-X) l-M-R (I) where R: a residue of a hydroxyl group-containing (meth) acrylate M: a residue of a polyvalent isocyanate X: 2,2- (dihydroxylmethyl) propionic acid or Residue l of other acid diols: A positive number is shown, and R, M and X are linked by a urethane bond.

This compound (I) has poor compatibility with various other ultraviolet or radiation curable monomers and oligomers, and a coating film obtained by curing an ultraviolet or radiation resin composition containing this compound (I) is Since the compound (I) causes phase separation, there are problems such as reduction in toughness of the coating film, white turbidity, reduction in surface gloss, and reduction in adhesion to a metal substrate.

Under such circumstances, the present inventors have found that the ultraviolet or radiation curable resin composition containing the carboxyl group-containing urethane (meth) acrylate in which the content of the compound (I) is reduced as much as possible has mechanical properties, It was found that a cured coating film with excellent transparency, surface gloss, and adhesion to metal substrates is formed, and that adhesion and dispersibility to metals and metal oxides are extremely excellent, and a manufacturing method thereof is examined. As a result of repeating the above, the present invention has been completed.

Next, a method for producing the carboxyl group-containing urethane (meth) acrylate-containing composition of the present invention will be described.

Raw Materials Hydroxyl group-containing (meth) acrylate Examples of the hydroxyl group-containing (meth) acrylate that can be used in the present invention include the following. 2-hydroxyethyl (meth) acrylate, 2-
Hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, ε-caprolactone adduct of 2-hydroxylethyl (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol triacrylate and the like.

Polyisocyanates that can be used in the present invention include, for example, tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, diphenylmethane-4,4-diisocyanate, isophorone diisocyanate, diisocyanates such as methyllysine diisocyanate, and 2 Mention may be made of triisocyanates such as 4,4,6-toluenthisocyanate. Among these, more preferred are diisocyanates.

Polyhydric alcohol The polyhydric alcohol used in the present invention may be divalent or higher, but dihydric alcohol is more preferable. The alcohol referred to here is a compound having a hydroxyl group in the molecule other than the acid diol, and for example, a) saturated polyester polyol b) unsaturated polyester polyol.
C) Polyether polyol d) Polycaprolactone polyol f) Fatty acid ester and the like can be mentioned. Specific examples thereof are as follows.

B) Saturated polyester polyols Polyhydric glycols such as ethylene glycol, propylene glycol, neopentyl glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,6-hexanediol and trimethylolpropane A saturated polyester polyol having a hydroxyl group, which can be obtained by an esterification reaction of an alcohol and a saturated polybasic acid such as phthalic acid, isophthalic acid, succinic acid, adipic acid, and sebacic acid.

(B) Unsaturated Polyester Polyol The unsaturated polyester polyol having a hydroxyl group obtained by substituting a part of the polybasic acid with a polybasic acid having an unsaturated bond such as maleic acid in the saturated polyester polyol described in (a) above.

C) Polyether polyol Polyethylene glycol, polypropylene glycol,
Propylene oxide adduct of polytetramethylene glycol and glycerin (Product name: Nissan Uniol TG-100
0), polyether polyol such as ethylene oxide adduct of bisphenol A (trade name: Nissan Uniol DA-400).

D) Polycaprolactone polyol A ring-opening polymer of ε-caprolactone, and examples of commercially available products include Placcel L-205AL and Placcel L-212AL (manufactured by Daicel Chemical Industries, Ltd.).

E) Fatty acid ester A fatty acid ester containing a hydroxyl group synthesized from a fat or oil fatty acid or a synthetic fatty acid and a polyhydric alcohol. As the fatty acid used as a raw material, soybean oil, peanut oil, cottonseed oil, safflower oil, olive oil, castor oil Castor oil is particularly preferably used. Other polyhydric alcohols as raw materials include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol and trimethylolpropane.

In addition to the polyhydric alcohols shown in the above a) to e), polybutadiene having a terminal hydroxyl group can be used. Further, it is safe to use two or more kinds of these alcohols at the same time.

Acid diol The acid diol used in the present invention is a dihydric alcohol having at least one carboxyl group in the molecule, such as 2,2-di (hydroxymethyl) propionic acid having one carboxyl group, 2 2,2-di (hydroxymethyl) butyric acid and tartaric acid having two carboxyl groups can be used.

Production method A resin composition containing a carboxyl group-containing urethane (meth) acrylate forms a cured coating film having excellent mechanical properties, transparency, surface gloss, and adhesion to a metal substrate, and a metal or metal oxide. In order to exhibit sufficient adhesion and dispersibility with respect to, it is important to minimize the by-product of the compound (I) during the production thereof. As a method for producing a carboxyl group-containing urethane (meth) acrylate for that purpose, the following two methods are extremely excellent.

The first method is <1> First, a terminal isocyanate acid diol adduct compound (A) is produced from an acid diol and a polyvalent isocyanate. The charging ratio of the acid diol and the polyisocyanate at this time is NCO group / OH group> 1 (molar ratio), and preferably NCO group / OH group ≧ 2 (molar ratio). The reaction temperature at this time is preferably 70 to 120 ° C, more preferably 80 to 110 ° C. Reaction temperature is 70 ℃
If it is lower, it is difficult to complete the reaction of the acid diol. On the contrary, if it is higher than 120 ° C, gelation is likely to occur due to side reaction.

<2> Subsequently, the terminal isocyanate acid diol adduct compound (A) produced in the previous step is reacted with a polyhydric alcohol to produce a carboxyl group-containing terminal hydroxyl group urethane oligomer (B). At this time, the charging ratio of the terminal isocyanate acid diol adduct compound (A) and the polyhydric alcohol must be OH group / NCO group> 1 (molar ratio).

<3> Further, the carboxyl group-containing terminal hydroxyl group urethane oligomer (B) produced in the previous step is added to and reacted with the polyvalent isocyanate at a ratio of NCO group / OH group> 1 (molar ratio) to obtain a carboxyl group-containing terminal isocyanate. A urethane oligomer (C) is produced.

<4> Finally, the carboxyl group-containing terminal isocyanate urethane oligomer (C) produced in <3> is added to and reacted with a hydroxyl group-containing (meth) acrylate at a ratio of OH group / NCO group ≧ 1 to contain a carboxyl group. Produce urethane (meth) acrylate.

The second method is a manufacturing method in which the following steps <5> and <6> are performed instead of the above steps <3> and <4>. That is, <5> Polyvalent isocyanate and hydroxyl group-containing (meth) acrylate are added at a ratio of NCO group / OH group ≧ 2 (molar ratio) and reacted to produce a terminal isocyanate (meth) acrylate adduct (D). .

<6> The above-mentioned terminal isocyanate (meth) acrylate adduct (D) and the terminal hydroxyl group urethane oligomer (B) produced in <2> are added at a ratio of OH group / NCO group ≧ 1 (molar ratio) to carry out the reaction. Carboxyl group-containing urethane (meth) acrylate is produced.

The above steps <3> and <4> or <5> and <6>
In the above, it is preferable to add phenols such as hydroquinone and hydroquinone monomethyl ether, quinones such as benzoquinone, and polymerization inhibitors such as phenothiazine and copper salt.

Further, it does not matter at all that a catalyst for the urethanization reaction or a reaction solvent is used in all the above steps. Examples of the catalyst for the urethanization reaction include triethylamine,
N-methylmorpholine, N, N, N ', N'-tetramethyl-
Tertiary amines such as 1,3-butanediamine, organotin compounds such as tin octenoate and dibutyltin dilaurate, or metal salts of Ti, Na, K, V, Fe, Mn and Pb can be used. On the other hand, the reaction solvent is preferably a ketone solvent such as methyl ethone ketone, methyl isobutyl ketone, or cyclohexanone, an ester solvent such as ethyl acetate or butyl acetate, an aromatic hydrocarbon solvent such as benzene, xylene, or toluene, or another solvent. Used.

Amount of catalyst or solvent used in each step, reaction temperature in steps <3> and <4> or <2>, <5> and <6>, and step <3> and <4> or <5> and The reaction conditions such as the amount of the polymerization inhibitor used in <6> are
All you have to do is follow the usual method.

Average Structure of Product The average structure of the carboxyl group-containing urethane (meth) acrylate produced by the present invention can be represented by the following formula when a divalent alcohol and a divalent isocyanate are used as raw materials.

RM- {N- (MY) _k- M} _m- N] _n- M-R where R: residue of hydroxyl group-containing (meth) acrylate M: residue of divalent isocyanate N: divalent alcohol Residue Y: acid diol residue k: positive number m: number of 0.7 or more n: number of 0.7 or more, and R, M, N and Y are bonded by a urethane bond.

In the above structural formula, k, m and n can be controlled by the reaction molar ratio of the raw material compounds, and a preferable value is that k is 10
The following positive numbers, more preferably 0.1 or more, and m or n is
It is 0.7 or more and 10 or less, more preferably 1 or more. k is 1
When it exceeds 0, the viscosity of the product is increased and the workability is deteriorated, and the curability by ultraviolet rays or radiation is deteriorated. If m or n is less than 0.7, the adhesion of the product to the metal and the dispersibility in the metal oxide may be deteriorated. Alternatively, the curability may be deteriorated by radiation.

Curing of Composition The resin composition produced by the present invention is easily cured by irradiation with ionizing radiation such as ultraviolet rays, X-rays and electron beams.

When the curing means is UV irradiation, a photoinitiator is used as a polymerization initiator. Examples of industrially frequently used photoinitiators include benzoin alkyl ether, benzophenone, N, N′-diethylaminobenzophenone,
2,2-diethoxyacetophenone, 2,2-dimethoxy-2
-Phenylacetophenone, 2-alkylthioxanthone, chlorothioxanthone, 1-phenyl-1,2-propanedioxime, chlorinated acetophenone derivatives and the like can be mentioned. The amount of these photoinitiators used is 0.01 to 20 wt% with respect to the composition, and more preferably 0.1 to 10 w.
t%.

When the curing means is radiation such as electron beam or γ-ray, it is not necessary to use a photoinitiator because it can be rapidly cured without using a photoinitiator.

EXAMPLES, COMPARATIVE EXAMPLES AND REFERENCE EXAMPLES Next, the contents of the present invention will be described more specifically with reference to Examples and Comparative Examples. The present invention is not limited to the embodiments.

Example 1 First, tolylene diisocyanate (hereinafter referred to as TDI) was placed in a 5 L four-necked flask equipped with a thermometer, a reflux condenser, and a stirrer.
174 parts (parts by weight, the same below), 67 parts of dimethylolpropionic acid (hereinafter referred to as DMPA), 1.0 part of dibutyltin dilaurate, methyl isobutyl ketone (hereinafter referred to as MIB).
Called K. ) 895 parts and toluene 895 parts were charged and reacted at a reaction temperature of 90-100 ° C. for 4 hours to obtain a terminal isocyanate acid diol adduct compound (A).

Then, to this terminal isocyanate acid diol adduct compound (A), 700 parts of Uniol D-700 (polypropylene glycol: molecular weight 700, manufactured by NOF CORPORATION) was added,
The reaction was carried out at 60-80 ° C for 4 hours to obtain a carboxyl group-containing terminal hydroxyl group urethane oligomer (B).

Further, TDI / 2-hydroxyethyl acrylate adduct (D) (hereinafter referred to as TDI / 2-HEA adduct) is added to the carboxyl group-containing terminal hydroxyl urethane oligomer (B).
Add 0 parts, react at 60-80 ℃ for 4 hours, acid value 0.41meq /
g (solid value), a carboxyl group-containing urethane acrylate (1) having a number average molecular weight of 3100 was obtained.

The method for producing the above TDI / 2-HEA adduct is as follows. 3 L 4 equipped with thermometer, reflux condenser, and stirrer
870 parts TDI, dibutyltin dilaurate in a one-necked flask
1.5 parts and 0.7 parts of hydroquinone monomethyl ether were charged, 580 parts of 2-hydroxyethyl acrylate was added dropwise while keeping the reaction temperature at 60-70 ° C, and after the addition, aging was carried out for 2 hours to obtain a TDI / 2-HEA adduct. .

Example 2 In the same manner as in Example 1, 174 parts of TDI, 67 parts of DMPA, 0.7 part of dibutyltin dilaurate, 594 parts of MIBK, and 594 parts of toluene.
Is used to obtain a terminal isocyanate diol acid adduct compound (A), and then Praxel L-208AL (manufactured by Daicel Chemical Industries, Ltd .: polycapron lactone polyol)
460 parts and URIC H-62 (castor oil-based polyol: molecular weight 4
20 and 198 parts of Ito Oil Co., Ltd. are added to obtain a carboxyl group-containing terminal hydroxyl group urethane oligomer (B). Further
Acid value of TDI / 2-HEA adduct (D) (290 parts)
A urethane acrylate (2) having 0.42 meq / g (solid content conversion value) and a number average molecular weight of 2400 was obtained.

Example 3 TDI 174 parts, DMPA 67 parts, dibutyltin dilaurate 0.9
Part, MIBK 700 parts and toluene 700 parts were added, and the reaction temperature was 90-1.
The reaction was carried out at 10 ° C for 3 hours to obtain a terminal isocyanate diol acid adduct compound (A). Next, 870 parts of Praxel L-208AL was added to the terminal isocyanate diol acid adduct compound (A), and the mixture was reacted at 70 to 90 ° C. for 3 hours,
A carboxyl group-containing terminal hydroxyl group urethane oligomer (B) was obtained. Furthermore, 191 parts of TDI was added to this carboxyl group-containing terminal hydroxyl group urethane oligomer (B), and the reaction temperature was
The reaction was carried out at 70-90 ° C for 4 hours to obtain a carboxyl group-containing terminal isocyanate urethane oligomer (C). Finally, the carboxyl group-containing isocyanate isocyanate urethane oligomer (C) was added to hydroquinone monomethyl ether.
0.7 parts and 127 parts of 2-hydroxyethyl acrylate were added and reacted at a reaction temperature of 60-80 ° C for 5 hours to give an acid value of 0.3.
A urethane acrylate (3) having 5 meq / g (solid content conversion value) and a number average molecular weight of 1860 was obtained.

Comparative Example 1 Using the same device as in Example 1, using TDI696 parts, DMPA134
Part and polyethylene glycol # 200 200 parts were charged in a flask and the reaction was started at 60 ° C. When temperature was difficult to control, the temperature of the reaction solution rose to 120 ° C. and gelled.

Comparative Example 2 Using the same device as in Example 1, using TDI348 part, DMPA67 part,
630 parts of Praxel L-212AL, 0.8 parts of dibutyltin dilaurate, 634 parts of MIBK, and 634 parts of toluene were charged into a flask and reacted at 60 ° C. for 7 hours to obtain a terminal isocyanate prepolymer solution. Next, 0.64 parts of hydroquinone monomethyl ether and 232 parts of 2-hydroxyethyl acrylate were added to this prepolymer solution and reacted at 60-80 ° C for 5 hours to give an acid value of 0.39 meq / g (solid content conversion value), number average. A carboxyl group-containing urethane acrylate (4) having a molecular weight of 2600 was obtained.

Reference example Using a doctor blade with a gap of 200 μm,
The carboxyl group-containing urethane acrylates (1) to (4) obtained in Examples and Comparative Examples were coated on a polyester film substrate, dried with hot air to remove the solvent, and then ESI.
The coating film was cured by irradiating an electron beam of 10 Mrad in a nitrogen atmosphere with an accelerating voltage of 170 KV using an electron curtain type electron beam irradiation device manufactured by the same company. The cured coating film was peeled off from the film substrate, and the transparency and mechanical strength of the coating film were measured.

On the other hand, to the carboxyl group-containing urethane acrylates (1) to (4) obtained in Examples and Comparative Examples, a photoinitiator (Darocurure 1173: manufactured by Merck Japan Ltd.) was added in an amount of 5% by weight based on the solid content. A coating composition was prepared, which was coated on a metal substrate using a bar coater # 200, dried with hot air, and cured by UV irradiation, and then subjected to a peel test to obtain a cured coating film. The adhesion to a metal substrate was examined. UV irradiation was performed by using Ushio Electric Co., Ltd.'s UV-4000, which was a single ultra-high pressure mercury lamp of 80 W / cm, and was irradiated once at a conveyor speed of 5 m / min from a distance of 10 cm on the conveyor. went.

The results are shown in Table 1.

Further, coating compositions having the compositions shown in Table 2 were prepared using the carboxyl group-containing urethane acrylates (1) to (4) obtained in Examples and Comparative Examples, and mixed and dispersed by a ball mill for 1 hour. After mixing and dispersion, gap spacing 200μm
The coating material is applied to the polyester base material using the doctor blade, and the solvent is dried and removed with hot air, and then electron beam irradiation with an acceleration voltage of 170 KV and 10 Mrad is performed using an ESI electron curtain type electron beam irradiation device. Was performed under a nitrogen atmosphere to cure the coating film. The results of measuring the surface gloss of the obtained coating film are shown in Table 3.

(C) Effect of the Invention As shown in Table 1, the resin composition obtained according to the present invention is excellent in the mechanical properties of the coating film and in the adhesion to the metal substrate, and is a cured film formed by phase separation. It gives a transparent film without the drawbacks of cloudiness and grain formation. Further, as shown in Table 3, metals and metal oxides are well dispersed.

The resin composition according to the present invention is utilized in the field of utilizing electron beam, ultraviolet ray and the like as a curing means by utilizing such characteristics, for example, paints, inks, conductive paints and the like.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Sadaaki Tsuji 13-26 Suehiro-cho, Yokkaichi-shi, Mie Ito Oil Co., Ltd. In-house Examiner Eiwa Hashimoto (56) References JP 61-179219 (JP, A) JP 62-10131 (JP, A) JP 59-30814 (JP, A) JP 61-211324 (JP, A) JP 61-192718 (JP, A) JP 54-139700 (JP, A) JP-A-1-134354 (JP, A)

Claims (2)

[Claims] (1) A terminal isocyanate acid diol adduct compound is obtained by reacting a polyvalent isocyanate and an acid diol in a molar ratio in which the ratio of the isocyanate group in the polyvalent isocyanate to the hydroxyl group in the acid diol exceeds 1. A step of producing (A), <2> A terminal isocyanate acid diol adduct compound (A) and a polyhydric alcohol, wherein the ratio of the hydroxyl group in the polyhydric alcohol to the isocyanate group in the adduct compound (A) exceeds 1. A step of producing a carboxyl group-containing terminal hydroxyl group urethane oligomer (B) by reacting in a molar ratio, <3> a carboxyl group-containing terminal urethane oligomer (B) and a polyvalent isocyanate in the urethane oligomer (B) Of the isocyanate groups in the polyvalent isocyanate for the hydroxyl groups A step of producing a carboxyl group-containing terminal isocyanate urethane oligomer (C) by reacting at a molar ratio of more than 1, and <4> a carboxyl group-containing terminal isocyanate urethane oligomer (C) and a hydroxyl group-containing (meth) acrylate. By reacting at a molar ratio such that the ratio of the hydroxyl group in the hydroxyl group-containing (meth) acrylate to the isocyanate group in the urethane oligomer (C) is 1 or more,
A process for producing a urethane (meth) acrylate containing a carboxyl group, comprising: a process for producing an ultraviolet- or radiation-curable resin composition. 2. A terminal isocyanate acid diol adduct compound is produced by reacting <1> a polyvalent isocyanate with an acid diol in a molar ratio in which the ratio of the isocyanate group in the polyvalent isocyanate to the hydroxyl group in the acid diol exceeds 1. A step of producing (A), <2> A terminal isocyanate acid diol adduct compound (A) and a polyhydric alcohol, wherein the ratio of the hydroxyl group in the polyhydric alcohol to the isocyanate group in the adduct compound (A) exceeds 1. A step of producing a carboxyl group-containing terminal hydroxyl group urethane oligomer (B) by reacting at a molar ratio, <3> a polyvalent isocyanate and a hydroxyl group-containing (meth) acrylate are mixed with a hydroxyl group in the hydroxyl group-containing (meth) acrylate. The ratio of isocyanate groups in the valent isocyanate is 2 or more By reacting with that molar ratio, terminal isocyanate (meth) acrylate adduct (D)
And (4) a carboxyl group-containing terminal hydroxyl group urethane oligomer (B) and a terminal isocyanate (meth) acrylate adduct (D) in the urethane oligomer (B) with respect to the isocyanate group in the adduct (D). And a step of producing a carboxyl group-containing urethane (meth) acrylate by reacting them in a molar ratio such that the ratio of the hydroxyl groups is 1 or more, and a method for producing an ultraviolet or radiation curable resin composition, comprising: