JPH07157531A - Production of water-based urethane acrylate - Google Patents

Abstract

PURPOSE:To obtain the subject resin excellent in water dispersibility, curability due to energy such as ultraviolet radiation and environmental protection, useful for e.g. coatings or adhesives, by neutralizing a resin produced from a specific polyol, organic diisocyanate and specific (meth)acrylate. CONSTITUTION:This resin is obtained by neutralizing a urethane acrylate resin >=10 in carboxyl concentration in terms of acid value, with ammonia, an inorganic base or amine, where the resin is made from (A) a lactone-based polyester polyol produced by ring opening addition polymerization of a lactone such as gamma-butylolactone or epsilon-caprolactone using a dihydrocarboxylic acid such as 2,2-dimethylolpropionic acid, as an initiator, (B) an organic diisocyanate such as tolylene diisocyanate and (C) a (meth)acrylate having OH in the molecule, e.g. 2-hydroxyethyl (meth)acrylate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an aqueous urethane acrylate which is rapidly cured by energy such as ultraviolet rays and electron beams to give a useful film.

[0002]

2. Description of the Related Art Water-based urethane acrylate resins, which can be rapidly cured by energy such as ultraviolet rays and electron beams, are useful for applications such as paints, adhesives, coating agents, and various binders. It is attracting attention as an aqueous industrial material containing no organic solvent.

Conventionally, a water-based urethane acrylate is produced by using a surfactant, a self-emulsifying method using a hydrophilic polyol such as polyethylene glycol as a polyol, and a hydrophilic group such as a carboxyl group in a urethane acrylate resin. A method of introducing a group, a sulfonic acid group, a tertiary amino group or the like is known.

As a method of introducing a hydrophilic group into urethane acrylate, the introduction of a carboxyl group is the easiest and is generally performed.

[0005]

As a method of introducing a carboxyl group, dihydroxycarboxylic acid is used as a chain extender. However, with this method, a carboxyl group is introduced into the hard segment, so that it becomes a crystalline portion of urethane. Therefore, the cohesive force becomes strong and satisfactory water solubility or water dispersibility cannot be obtained. Therefore, by increasing the amount used, the water solubility or water dispersibility is cut off with a cover, but there is a drawback that the ratio of hard segments increases and the required physical properties are difficult to balance.

[0006]

OBJECT OF THE INVENTION The object of the invention is to remedy these drawbacks,
It is to produce a urethane acrylate excellent in water solubility or water dispersibility.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that when synthesizing a polycaprolactone polyol, by using dihydroxycarboxylic acid as an initiator, one polycaprolactone polyol has a carboxyl group. One can be surely introduced, and
The inventors have found that the carboxyl groups in the urethane acrylate resin can be adjusted arbitrarily, and have reached the present invention.

That is, the present invention relates to "(A) a lactone-based polyester polyol obtained by subjecting a lactone to ring-opening addition polymerization using a dihydroxycarboxylic acid as an initiator (B) an organic diisocyanate (C) at least one in one molecule. Water-based urethane acrylate, which is produced by neutralizing urethane acrylate having a carboxyl group concentration of 10 or more with (meth) acrylates having a hydroxyl group with ammonia, inorganic bases or amines. Method ".

The water-based urethane acrylate obtained by the method of the present invention has a greatly improved water solubility or water dispersibility by containing a carboxyl group in the soft segment.

The lactone type polyester polyol obtained by ring-opening addition polymerization of lactones using the dihydroxycarboxylic acid as the component (A) in the present invention is a ring-opening addition polymerization of lactones to dihydroxycarboxylic acid in the presence of a catalyst. By doing so, it can be synthesized. Examples of the dihydroxycarboxylic acid include 2.2 dimethylolpropionic acid, tartaric acid and dioxyadipic acid.

As lactones, ε-caprolactone,
Examples include γ-butyrolactone and δ-valerolactone.

The ring-opening addition polymerization of the dihydroxycarboxylic acid and the lactone proceeds as follows in the case of 2.2 dimethylolpropionic acid and ε-caprolactone.

[Chemical 1] Examples of the catalyst used in the ring-opening addition polymerization include organic titanium compounds such as tetraethyl titanate, tetrabutyl titanate and tetrapropyl titanate, tin octylate, dibutyltin oxide, organic tin compounds such as dibutyltin dilaurate, stannous chloride and stannous bromide. Suitable are tin, stannous halide such as stannous iodide, etc., and 0.1 to 1000 ppm, preferably 1 to 1 relative to the charged raw material.
000 ppm is used. The reaction temperature is 90 to 240 ° C, preferably 110 to 220 ° C. Also, during the reaction, synthesis in an atmosphere of an inert gas such as nitrogen gas gives good results on the hue of the product. The average molecular weight can be adjusted by changing the number of moles of lactones added to dihydroxycarboxylic acid.

As described above, the lactone type polyester polyol which is the component (A) of the present invention is synthesized. The lactone polyester polyol used preferably has an average molecular weight of 500 to 5,000.

The organic diisocyanate which is the component (B) in the present invention includes tolylene diisocyanate, 4,
Aromatic, aliphatic and alicyclic diisocyanates such as 4-diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, and 4,4-dicyclohexyl diisocyanate can be used.

Furthermore, 1 which is the component (C) in the present invention
Examples of (meth) acrylates having at least one hydroxyl group in the molecule include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3
(Meth) acrylates such as -hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, pentaerythritol di (meth) acrylate and pentaerythritol tri (meth) acrylate. .

The urethane acrylate produced by the production method of the present invention is synthesized by using the above-mentioned components.
ex (equivalent of NCO / OH) is O.V. 85 to 1.2, preferably 0.9 to 1.1.

For the urethanization reaction in the present invention, a conventionally known method may be used, for example, a one-shot method in which all components are reacted simultaneously, or a prepolymer having an isocyanate-terminated prepolymer by reacting a polyol with an organic isocyanate is used. Any method may be used, such as a prepolymer method of synthesizing and then reacting (meth) acrylates having at least one hydroxyl group in one molecule.

These reactions may be carried out without solvent or in a solvent which is inert with the isocyanate group. As the solvent in that case, a water-soluble solvent is preferable. Examples thereof include ketone solvents such as acetone and methyl ethyl ketone, amide solvents such as dimethylformamide, and pyrrolidone solvents such as N-methyl-2-pyrrolidone. Further, in these urethanization reactions, as a catalyst, an organic tin compound such as dibutyltin dilaurate, N
-A tertiary amine such as methylmorpholine or triethylamine may be used. In the production of the water-based urethane acrylate of the present invention, a long-chain diol having no carboxyl group together with a lactone polyester polyol having a carboxyl group, that is, polycaprolactone diol,
Polyester diol, polytetramethylene glycol, polypropion glycol, polyethylene glycol, and aliphatic polycarbonate diol can be used in combination as long as the characteristics of the present invention are not impaired.

The urethane acrylate obtained by the above method of the present invention has a carboxyl group concentration of 10 or more, preferably 15 to 200.

The urethane acrylate resin containing a carboxyl group is neutralized with ammonia, inorganic bases or amines to obtain an aqueous urethane acrylate. Examples of suitable inorganic bases here include sodium hydroxide,
Examples include potassium hydroxide and the like. Examples of the amines include monopropylamine, monobutylamine, diethylamine, triethylamine, tributylamine, monoethanolamine, monocyclohexylamine and the like. These neutralizing agents are preferably used in an equivalent amount with respect to the carboxyl group.

Next, the present invention will be described with reference to examples, but the present invention is not limited thereto.
In addition, the part in a synthesis example, an Example, and a comparative example shows a weight part number.

[Synthesis Example 1] 281.4 parts of 2,2-dimethylolpropionic acid and ε-caprolactone 768. were added to a reactor equipped with a gas introduction pipe, a thermometer, a cooling pipe and a stirring device.
6 parts were charged and 0.001 stannous chloride was used as a catalyst.
Charge 53 parts (5 ppm), and under nitrogen gas atmosphere, 12
The reaction was carried out at 0 ° C., and the amount of residual ε-caprolactone was 0.5.
% Or less, the reaction was stopped to obtain an oligomer-A (lactone type polyester polyol).

[Synthesis Example 2] 222 parts of isophorone diisocyanate and 0.13 parts (200 ppm) of dibutyltin dilaurate as a catalyst were placed in a reactor equipped with a gas introduction tube, a thermometer, a cooling tube and a stirrer. After charging, the temperature was maintained at 70 ° C. under a nitrogen gas atmosphere. Then Oligomer-A261
Parts were added to obtain a prepolymer having an isocyanate concentration of 8.7% in terms of solid content of 100%. Then, in a dry air atmosphere, 2-hydroxyethyl acrylate 11
7.8 parts was gradually added, the reaction was continued as it was, and the isocyanate concentration was 0.01% in terms of the solid content concentration of 100%.
The reaction was stopped at a rate of not more than%, and oligomer B was obtained.

[Synthesis Example 3] The charged amount of ε-caprolactone was 3918.6 parts, and the charged amount of stannous chloride was 0.0.
Synthesis was performed in the same manner as in Synthesis Example 1 except that the amount was changed to 21 parts to obtain oligomer-C.

[Synthesis Example 4] Synthesis was carried out in the same manner as in Synthesis Example 2 except that Oligomer-C was used instead of Oligomer-A to obtain Oligomer-D.

[Synthesis Example 5] Pentaerythritol triacrylate instead of 2-hydroxyethyl acrylate
Synthesis was carried out in the same manner as in Synthesis Example 2 except that 302.5 parts of G.

[Synthesis Example 6] Pentaerythritol triacrylate instead of 2-hydroxyethyl acrylate
Oligomer-F was obtained in the same manner as in Synthesis Example 4 except that 302.5 parts of G.

[Synthesis Example 7] Oligomer G was obtained by the same method as in Synthesis Example 1 except that 130.2 parts of diethylene glycol was used in place of 2,2-dimethylolpropionic acid. It was [Synthesis Example 8] Oligomer-H was obtained by performing synthesis in the same manner as in Synthesis Example 2 except that Oligomer-G was used instead of Oligomer-B.

[Synthesis Example 9] 130.2 parts of diethylene glycol was used in place of 2,2-dimethylolpropionic acid, and the amount of ε-caprolactone charged was 3918.6.
Parts and stannous chloride were changed to 0.021 parts, and synthesis was carried out in the same manner as in Synthesis Example 1 to obtain oligomers.
Got I.

[Synthesis Example 10] Oligomer-J was obtained by the same method as in Synthesis Example 2 except that Oligomer-I was used instead of Oligomer-A.

Examples and Comparative Examples Using the above samples, aqueous urethane acrylates were prepared with the composition shown in Table 1 and the solubility, pencil hardness, water resistance, stain resistance, breaking strength and elongation were measured. .

The results are shown together in Table 1.

Table 1 Examples Comparative Example 1 2 3 4 1 2 3 Oligomer B 40 40 Oligomer D 40 Oligomer E 40 Oligomer F 40 Oligomer H 40 Oligomer J 40 Monoethanol 3.3 1.1 2.2 0.9 3.7 1.1 Amine photopolymerization initiator * 4 4 4 4 4 4 4 Water 56.7 58.9 57.8 59.1 60 56.3 58.9 Solubility ○ ○ ○ ○ × × × Pencil hardness 6B 6B 5B 6B Water resistance ○ ○ ○ ○ Contamination resistance Red ink ○ ○ ○ ○ Black ink ○ ○ ○ ○ Breaking strength 165 180 210 200 (kgf / cm ² ) Elongation (%) 30 45 5>5> * Photopolymerization initiator: Darocur1173 (MERCK
As a sample for evaluation, the above sample was coated on a glass substrate with an applicator so as to have a thickness of 100 μm, preliminarily dried at 120 ° C. for 3 minutes, and a high pressure mercury lamp (lamp input 120 W / cm).
At that time, ultraviolet rays were irradiated at a conveyor speed of 15 m / min.

Solubility ○: Good ×: Not dissolved Pencil hardness Measured on glass plate Water resistance Observed with water on cured film ○: No change on film surface △: Wrinkles and whitening slightly ×: There is wrinkle and whitening. Contamination resistance. Mark on the cured film with an oil-based ink (red, black), and wipe off with isopropyl alcohol after 24 hours.

◯: No ink traces Δ: Ink traces are slightly visible ×: Ink traces are clearly visible [Effect of the invention] As described above with reference to the examples, by using dihydroxycarboxylic acid as an initiator, ammonia can be obtained. A water-based urethane acrylate resin can be easily obtained by neutralizing with an inorganic base or an amine. (Below margin)

Claims (1)

[Claims] 1. A lactone-based polyester polyol (B) obtained by subjecting (A) a dihydrocarboxylic acid as an initiator to ring-opening addition polymerization of lactones (B) an organic diisocyanate (C) having at least one hydroxyl group in one molecule ( A method for producing a water-based urethane acrylate, which comprises producing a urethane acrylate resin having a carboxyl group concentration of 10 or more and comprising a (meth) acrylate and neutralizing it with ammonia, inorganic bases or amines.