JP2006312668A - Acrylic-modified urethane resin and its composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acrylic-modified urethane resin which is safe and has an excellent product quality, and to provide a photocurable acrylic-modified urethane resin composition using the acrylic-modified urethane resin. <P>SOLUTION: This acrylic-modified urethane resin obtained by reacting an organic polyisocyanate with a polyol in the presence of a high boiling point acrylate or methacrylate having a CPR value of ≤10. The photocurable acrylic-modified urethane resin composition comprises the acrylic-modified urethane resin, a specific acrylic oligomer and a photopolymerization initiator. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an acrylic modified urethane resin obtained by modifying a urethane resin in the presence of a specific acrylic monomer, and a curable composition containing the acrylic modified urethane resin.

In general, urethane resins are excellent in scratch resistance, flexibility, and substrate adhesion, and are used in various coating materials and molding materials. However, they have a drawback of poor hydrolysis resistance and weather resistance. In recent years, attempts have been made to improve the defects while taking advantage of the urethane resin by modifying the urethane resin with an acrylic resin.
Due to the recent increase in regulations on organic solvents, attempts have been made to react organic isocyanates and polyols using acrylic monomers as diluents without using organic solvents as diluents in the methods for producing acrylic-modified urethane resins.
Furthermore, the composition obtained by dissolving the acrylic modified urethane resin in acrylic acid ester or methacrylic acid ester makes use of various features such as weather resistance, flexibility, chemical resistance, adhesion, ink, paint, Applications to adhesives, coating materials, and sealing materials are expected.

A production method in which an organic isocyanate and a polyol are reacted (hereinafter referred to as a urethanization reaction) as a diluent for an acrylic ester or a methacrylic ester (hereinafter referred to as an acrylic monomer) is known (Japanese Patent Laid-Open No. 7-242866, In JP-A-2002-138128), the acrylic monomer in such a case has a low boiling point, and only has 12 or less carbon atoms in the side chain.
Such an acrylic monomer can be purified by a distillation step, and even when used as a diluent for a urethanization reaction, the reaction was runaway and the molecular weight did not increase abnormally even when it was used as a diluent.
However, when an acrylic-modified urethane resin containing the acrylic monomer is used in a photocurable composition, the acrylic monomer is scattered by the heat generated by the lamp during light exposure, which may change the physical properties of the cured product. Therefore, in the case of a photocurable composition, it is necessary to use a high boiling acrylic acid ester or methacrylic acid ester (hereinafter referred to as an acrylic oligomer), but the urethane oligomer is used as a diluent for the urethanization reaction. When it did, there existed a problem that reaction generate | occur | produced with large heat_generation | fever and the molecular weight of the acrylic modified urethane resin obtained increased abnormally.
Therefore, there has been a demand for an acrylic-modified urethane resin that is safe and has excellent productivity and product quality.

Japanese Patent Laid-Open No. 7-242866 JP 2002-138128 A

  The first object of the present invention is to provide an acrylic-modified urethane resin produced by a method that is safe and has excellent productivity and product quality by using a specific acrylic oligomer. The second problem is to provide a photocurable acrylic modified urethane resin composition comprising the acrylic modified urethane resin obtained in the first problem, a specific acrylic oligomer, and a photopolymerization initiator as essential components. It is.

As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.
That is, in the present invention, when an acrylic oligomer having a CPR value exceeding 10 is used as a diluent in the urethanization reaction, there is a risk that the side reaction of the isocyanate group is promoted and the reaction runs out of control. The present inventors have discovered and solved that it is difficult to produce a modified urethane resin and that the quality and physical properties of the photocurable composition of the acrylic modified urethane resin are insufficient.
Specifically, when the organic polyisocyanate and the polyol are reacted in the presence of a diluent, the diluent is an acrylic oligomer having a CPR value of 10 or less, and the acrylic The present invention relates to a photocurable acrylic modified urethane resin composition comprising a modified urethane resin, an acrylic oligomer having a CPR value of 10 or less, and a photopolymerization initiator as essential components.

  According to the present invention, an acrylic modified urethane resin that is safe and has excellent productivity and product quality, and a photocurable acrylic modified urethane resin composition having good water resistance and moisture resistance using the acrylic modified urethane resin are provided. Can do.

Details of the invention are described below.
The acrylic oligomer used in the present invention should have a CPR value of 10 or less, preferably 5 or less. Here, the CPR value is Chain Polymerization Rate, which is well known in the urethane manufacturing industry. Here, the CPR value of 10 is 0.033 meq / g when measured with 1 / 100N hydrochloric acid, and the CPR value of 5 is 1,0167 meq / g when measured with hydrochloric acid. Value.
The acrylic oligomer which is the subject of the present invention is difficult to purify by distillation. For example, (meth) acrylic acid ester of alkylene oxide modified phenol, (meth) acrylic acid ester of alkylene oxide modified nonylphenol, (poly) alkylene (Meth) acrylate of glycol (meth) acrylate, (meth) acrylate of alkylene oxide modified bisphenol A, (meth) acrylate of alkylene oxide modified p-cumylphenol, (meth) acrylic acid of alkylene oxide modified 2-ethylhexyl Esters, (meth) acrylic esters of alkylene oxide modified bisphenol F, (meth) acrylic esters of tricyclodecane dimethylol, (meth) of alkylene oxide modified (di) glycerin (Meth) acrylic acid ester of (di) pentaerythritol, (meth) acrylic acid ester of (di) trimethylolpropane, alkylene oxide modified (di) trimethylolpropane (meth) acrylic acid ester, alkylene oxide Examples thereof include (meth) acrylic acid esters of modified pentaerythritol, polyester acrylates, and epoxy acrylates. In this report, (meth) acrylic acid means acrylic acid or methacrylic acid.
For the purpose of the present invention, it is preferable to use an acrylic oligomer having a boiling point of 10 torr and a temperature of 200 ° C. or higher.

The acrylic oligomer that is the subject of the present invention is produced by the following steps.
Step 1: (Meth) acrylic acid and alcohol are esterified in the presence of an esterification catalyst in the presence of an organic solvent.
Step 2: In order to remove excess (meth) acrylic acid and esterification catalyst, the reaction solution is washed with an alkaline aqueous solution.
Step 3: The reaction solution after alkali washing is washed with washing water selected from pure water, water in which an inorganic salt is dissolved, weak acid water and strong acid water.
Step 4: The organic solvent is removed by distillation to obtain the desired product.
Instead of the step 3, it is also possible to remove the alkaline aqueous solution dispersed in the reaction solution by centrifuging the reaction solution after alkali washing.
In order to remove the alkali, the treatment may be performed with activated clay, an acid ion exchange resin, a molybdate compound, a tungstic acid compound, a heteropolyacid compound, a phosphoric acid compound, or the like.
Among these, the method described in the above step 3 is preferable in that the CPR value can be easily reduced to 10 or less by a simple operation.

  Examples of the organic isocyanate used in the present invention include diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), naphthalene diisocyanate (NDI), tetramethylxylene diisocyanate (TMXDI), isophorone diisocyanate (IPDI), Hydrogenated xylylene diisocyanate (H6XDI), dicyclohexylmethane diisocyanate (H12MDI), hexamethylene diisocyanate (HDI), hexamethylene diisocyanate trimer, norbornadiene diisocyanate (NBDI), trimethylhexamethylene diisocyanate (TMDI), 1,3- Urethane pre such as propanediol NCO adduct, TDI modified PPG Examples thereof include polymers and other NCO-containing compounds.

The polyol used in the present invention has two or more hydroxyl groups in one molecule. For example, polyether polyol, polyolefin polyol, hydrogenated polybutadiene polyol, polyester polyol, polycarbonate polyol, ethylene glycol, propylene glycol, tetramethylene glycol, glycerin, trimethylolpropane and the like can be mentioned.
It is also possible to introduce a (meth) acryl group into the urethane resin by using a part of acrylic monomers such as hydroxyethyl (meth) acrylate and hydroxybutyl (meth) acrylate.

The ratio of the organic isocyanate and polyol of the present invention is preferably 1/1 to 3/1 in terms of the molar ratio of NCO group / OH group, and the isocyanate is excessive.
In the urethane reaction, in the presence of the acrylic oligomer, the organic isocyanate and the polyol may be added simultaneously, or either the organic isocyanate or the polyol may be charged first, and the other may be dropped, or the entire amount may be batched. You may make it react after charging.
Alternatively, the organic isocyanate and polyol may be reacted first and then diluted with the acrylic oligomer.
In the reaction, a tin compound such as dibutyltin dilaurate or dibutyltin diacetate or an amine such as triethylamine may be used as a catalyst for the urethanization reaction.
The urethanization reaction is preferably performed at room temperature to 120 ° C. If an acrylic oligomer having a CPR value of 10 or less is used, it can be easily controlled to be constant within this temperature range.

  The number average molecular weight of the urethane resin obtained by the reaction is preferably 1000 to 40000. The ratio of the urethane resin and the acrylic oligomer is preferably 5/95 to 95/5 (weight ratio), and more preferably 30/70 to 60/40 (weight ratio). If the ratio of the acrylic oligomer is too small, the hydrolysis resistance and weather resistance are not improved, and if it is too large, the flexibility is deteriorated.

The acrylic modified urethane resin of the present invention can be further mixed with the acrylic oligomer of the present invention and a photopolymerization initiator to prepare a photocurable acrylic modified urethane resin composition.
The acrylic oligomer of the present composition also preferably has a CPR value of 10 or less from the viewpoint of the water resistance, moisture resistance and corrosion resistance of the composition.
Examples of the photopolymerization initiator of the present invention include benzoin such as benzoin, benzoin methyl ether and benzoin propyl ether; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1 Acetophenones such as dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one and N, N-dimethylaminoacetophenone; 2-methyl Anthraquinones such as anthraquinone, 1-chloroanthraquinone and 2-amylanthraquinone; 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone and 2,4-diisopropylthioxanthate Such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenone, methylbenzophenone, 4,4′-dichlorobenzophenone, 4,4′-bisdiethylaminobenzophenone, Michler's ketone, 4-benzoyl-4′-methyldiphenyl sulfide, etc. Benzophenone; and 2,4,6-trimethylbenzoyldiphenylphosphine oxide.
The photopolymerization initiator is preferably added in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the total amount of the acrylic modified urethane resin and the acrylic oligomer.
The ratio of the acrylic modified urethane resin and the acrylic oligomer of the present invention is preferably 10/90 to 90/10 (weight ratio) in the former / the latter.
In addition to the above components, an antifoaming agent, a leveling agent, an inorganic filler, an organic filler, a light stabilizer, an antioxidant, an ultraviolet absorber, and the like can be blended as necessary. If necessary, a small amount of an antioxidant, a light stabilizer, an ultraviolet absorber, a polymerization inhibitor, and the like may be added.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In the following, “parts” means parts by weight.
○ Measurement method of CPR value Sample Wg was weighed and dissolved in 30 cc of methanol. Subsequently, it titrated with 0.01 mol / L hydrochloric acid to the pH inflection point by an automatic pH measuring device. The titer at this time was Dml. The blank titer determined in the same manner was defined as Bml.
A numerical value converted to 30 g of product using the titration result was obtained as a CPR value (Formula 1).
CPR value = ((D−B) × 30 × 10 × F) / W Equation 1
Here, F is a factor of 0.01 mol / L hydrochloric acid.
The titration value of 1 / 100N hydrochloric acid is obtained from the following formula (Formula 2).
1 / 100N hydrochloric acid titration value (meq / g) = ((D−B) × F) / W Equation 2

-Production example of acrylic oligomer [Production Example 1]
In a four-necked flask having a stirrer, a condenser, a thermometer, and a charging port, 480 parts of tricyclodecane dimethylol (TCD-alcholDM manufactured by Celanese), 410 parts of acrylic acid, 21 parts of p-toluenesulfonic acid (PTS), Methoxyhydroquinone (MQ) 2.8 parts, phenothiazine 0.2 parts, toluene 500 parts, water to be purified at a reaction pressure of 400 Torr and an internal temperature of 85 to 105 ° C. until the conversion is 95% or more based on alcohol. The esterification reaction was performed while sequentially removing. Next, the reaction solution was diluted with 300 parts of toluene, and washed with 1/10 amount of distilled water with respect to the diluted reaction solution amount. The acid content of this diluted reaction solution was neutralized twice with a 20% aqueous solution containing an equivalent amount of caustic soda.
The diluted reaction liquid was washed with 5% ammonium sulfate water so that the ratio of 5% ammonium sulfate water (weakly acidic water) / diluted reaction liquid was 1/6.
Next, toluene was removed by distillation under reduced pressure to obtain tricyclodecane dimethylol acrylate having a boiling point of 10 torr and a temperature of 200 ° C. or higher. The CPR value of this product was 6.5 (0.022 meq / g in terms of 1 / 100N hydrochloric acid titration value).

[Production Example 2]
An acrylic oligomer was produced in the same manner as in Production Example 1 except that the washing treatment was performed 5 times with the same amount of distilled water instead of 5% ammonium sulfate water. The CPR value at this time was 4.2 (1 / 100N hydrochloric acid titration value was 0.014 meq / g).

[Comparative Production Example 1]
An acrylic oligomer was produced in the same manner as in Production Example 1 except that the washing was performed once with distilled water instead of 5% ammonium sulfate. The CPR value at this time was 35.1 (1 / 100N hydrochloric acid titration value was 0.117 meq / g).

○ Acrylic modified urethane resin [Example 1]
In a reactor equipped with a stirrer, thermometer, and nitrogen blowing tube immersed in an oil bath, 70 parts of the acrylic oligomer of Production Example 1 and 150 parts of bifunctional polypropylene oxide (Mw / Mn = 1.1) having a number average molecular weight of 2,000. Part, tolylene diisocyanate (mixture of 2,4-isomer and 2,6-isomer), 55 parts of dibutyltin dilaurate and 0.1 part of phenothiazine were added and reacted at 70 ° C. under a nitrogen stream. Within 8 hours after the start of the reaction, the internal temperature of the reactor was controllable within ± 10 ° C., and the molecular weight of the resulting acrylic-modified polyurethane resin was 3800 (Mw / Mn = 1.6).

[Example 2]
The same test as in Example 1 was performed except that the acrylic oligomer of Production Example 2 was used. The reaction temperature was constant within ± 5 ° C., and the molecular weight of the resulting acrylic-modified polyurethane resin was 3000 (Mw / Mn = 1.3).

[Comparative Example 1]
The same test as in Example 1 was performed except that the acrylic oligomer of Comparative Production Example 1 was used. An exotherm was observed 30 minutes after the start of the reaction, and one hour later the internal temperature rose to 130 ° C., so the reactor was pulled up from the oil bath and cooled. The molecular weight of the obtained acrylic-modified polyurethane resin was also 51000 (Mw / Mn = 5.2).

-Photocurable acrylic modified urethane resin composition [Example 3]
A photocurable acrylic modified urethane resin composition was prepared by blending 100 parts of the acrylic modified polyurethane resin produced in Example 1, 50 parts of the acrylic oligomer of Production Example 1 and 5 parts of Irgacure 184 manufactured by Ciba Specialty Chemicals. . The resin composition was applied on a PET sheet so as to have a film thickness of 1 mm, and was cured by a conveyor type high-pressure mercury lamp irradiator under conditions such that the irradiation amount was about 365 nm and the amount was 500 mj / cm ² . The resulting cured film was left at room temperature for one week and then immersed in 50 ° C. warm water overnight. As a result, no whitening or swelling was observed on the sheet.

[Comparative Example 2]
Except for using the acrylic modified polyurethane resin produced in Comparative Example 1 and the acrylic oligomer produced in Comparative Production Example 1, the same composition as in Example 3 was prepared and the same test was performed. As a result, whitening and swelling of the sheet were observed.

The acrylic-modified urethane resin obtained in the present invention is safe and excellent in productivity and product quality. Moreover, the photocurable acrylic modified urethane resin composition of the present invention is excellent in water resistance, moisture resistance and weather resistance, and is useful for inks, paints, adhesives, sealing materials and the like.

Claims (3)

An acrylic-modified urethane resin characterized in that an organic polyisocyanate and a polyol are reacted in the presence of an acrylic ester or methacrylic ester having a CPR value of 10 or less. 2. The acrylic modified urethane resin according to claim 1, wherein the boiling point of the acrylic ester or methacrylic ester is 200 ° C. or more at 10 torr. 3. A photo-curable acrylic modification comprising the acrylic-modified urethane resin according to claim 1 having an CPR value of 10 or less, a boiling point of 10 torr and an acrylic ester or methacrylic ester of 200 ° C. or higher, and a photopolymerization initiator as essential components. Urethane resin composition.