JP2764324B2 - Method for producing polycarbonate acrylate resin or polycarbonate methacrylate resin - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a polycarbonate acrylate resin or a polycarbonate methacrylate resin. More specifically, production of an acrylate resin or methacrylate resin which is a polyfunctional acrylate oligomer or methacrylate oligomer and has a function of forming a cured coating film excellent in wet heat resistance because it is an oligomer having a carbonate bond excellent in photocurability. About the method.

[Prior Art] One of the recent successes in which paints have become generally low-pollution, resource-saving, and energy-saving types is a paint made of an ultraviolet-curable resin composition.

It consists of a reactive composition that contains virtually no volatile solvent and contains a reactive diluent that is a polymerizable monomer that reacts with the resin during curing and becomes part of the protective coating itself. is there.

Generally, an ultraviolet curable resin composition comprises a photopolymerizable prepolymer, a photopolymerizable monomer, a photoinitiator, a sensitizer, a colorant and other additives (viscosity improver, antioxidant, polymerization inhibitor, wetting assistant). , Dispersants, desiccants, etc.).

Also, when using an electron beam curing system,
Curing can be performed in the same manner as in the case of ultraviolet light without a photoinitiator and a sensitizer.

These UV or electron beam curable resin compositions are used for paints, adhesives, printing ink vehicles, solder resist inks, letterpress materials, mortar floor linings, PVC tile coatings, optical fiber coating materials, plastic coatings, etc. It is used for

What greatly contributes to the basic physical properties of a cured resin (paint, ink, film, etc.) is a photopolymerizable prepolymer, also called a base resin. In addition, although the photopolymerizable prepolymer is usually called a polymer, it has a small degree of polymerization and is not called an oligomer because it is not included in the category of a polymer such as a resin for a molded article. Those having one to several functional groups are common.

Prepolymers can be classified into polyester acrylates, epoxy acrylates, polyurethane acrylates, polyether acrylates, oligo acrylates, alkyd acrylates, polyol acrylates, etc. according to the molecular structure that constitutes the skeleton. Form an object.

Among the above various acrylate oligomers, polyester acrylate has heat resistance, high hardness, toughness,
It has excellent performance such as flexibility, and its application field is wide.

On the other hand, in each acrylate oligomer, studies are being made to increase the number of functional groups, thereby increasing the crosslink density, and increasing the number of carbon atoms in the basic skeleton to impart flexibility.

[Problems to be Solved by the Invention] However, polyester acrylates having excellent performance as described above have strong anaerobic properties, and have a drawback that surface curing is poor due to radical consumption by oxygen in the air, and However, the market is also demanding an improvement in wet heat resistance.

Therefore, the present inventors have improved the above-mentioned drawbacks of the polyester acrylate resin, provided a cured coating film having excellent wet heat resistance, and have excellent curability and a photopolymerization capable of improving the crosslink density. As a result of diligent research on a functional prepolymer, in a polyfunctional polycarbonate polyol, the above-mentioned disadvantages have been solved by using an acrylate resin or a methacrylate resin obtained by reacting acrylic acid or methacrylic acid with all or a part of hydroxyl groups. A production method has been reached in which a photopolymerizable prepolymer can be obtained.

[Means for Solving the Problems] That is, the present invention provides a method of producing a polycarbonate polyol by subjecting a polycarbonate diol to a transesterification reaction with a trifunctional or higher polyfunctional polyol, and obtaining all or one of the hydroxyl groups of the obtained polycarbonate polyol. A method for producing a polycarbonate acrylate resin or a polycarbonate methacrylate resin, characterized by reacting acrylic acid or methacrylic acid with a part thereof.

 Next, the present invention will be described in more detail.

The polycarbonate polyol in the present invention is described in Japanese Patent Application No. 1-264513 (filed on Oct. 11, 2001: title of the invention: polycarbonate polyol (Japanese Unexamined Patent Publication No.
No. 33)), which is obtained by mixing a polycarbonate diol with a triol or tetraol and subjecting the mixture to a transesterification reaction.

That is, as the final product, as shown in the following formula,
Diol component (ie, polycarbonate diol, primary aliphatic diol, or alicyclic diol)
And a triol component (ie, a polycarbonate triol or a first aliphatic triol), a tetraol component (ie, a polycarbonate tetraol or a first aliphatic tetraol), and a polyol component (ie, a polycarbonate polyol).

aDI + bTRI + cTETRA → (a + b + c) BLEND (OH) _f where DI in the above formula is polycarbonate diol,
TRI represents triol, TETRA represents tetraol, BLEND represents a homogeneous mixture obtained by the transesterification reaction described above, and a, b, and c represent the number of moles of DI, TRI, and TETRA, respectively.

(OH) f represents the average number of hydroxyl groups (functional groups) of the homogeneous mixture obtained by the transesterification reaction as f.

(DI) used during the synthesis of the above polycarbonate polyol has a structure in which an alkylene group is arranged in a main chain via a carbonate bond, and is prepared by a known method (phosgene method, chloroformate method, aliphatic or aromatic carbonate). By the transesterification reaction using a diol compound described below.

Examples of the diol compound include diethylene glycol, triethylene glycol, tetraethylene glycol, tripropylene glycol, and polypropylene glycol, and ethylene glycol, 1,2-propanediol, 1,3-butanediol, and 2-methyl-1,3-butane. Diol, neopentyl glycol, hydroxypivalic acid ester of neopentyl glycol, 2-methylpentanediol, 3-methylpentanediol, 2,2,4-
Trimethyl-1,6-hexanediol, 3,3,5-trimethyl-1,6-hexanediol, 2,3,5-trimethylpentanediol, 1,6-hexanediol and the like can be used.

The triol (TRI) used in the synthesis of the polycarbonate polyol is a compound having three hydroxyl groups, specifically, trimethylolpropane, or a first aliphatic triol such as trimethylolethane, glycerin, or Tri- (2-hydroxyethyl) isocyanurate and the like can be used.

The tetraol (TETRA) used in the synthesis of the polycarbonate polyol is a compound having four hydroxyl groups. Specifically, in addition to the first aliphatic tetraol such as pentaerythritol, ditrimethylolpropane, etc. Can be used.

The transesterification can be carried out by a conventional method in the presence of a commonly used catalyst. Examples of the catalyst include lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium,
There are metals such as barium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, arsenic and cerium and their alkoxides.
Examples of other suitable catalysts include carbonates of alkali and alkaline earth metals, zinc borate, zinc oxide, lead silicate, lead arsenate, lead carbonate, antimony trioxide, germanium dioxide, cerium trioxide, And aluminum isopropoxide. Particularly useful and preferred catalysts are organometallic compounds such as metal salts of organic acids magnesium, calcium, cerium, barium, zinc, tin, titanium and the like.

The amount of the catalyst used ranges from 0.0001% to 1.0% of the total weight of the starting materials.
%, Preferably 0.001 to 0.2%.

The actual reaction is carried out by mixing the polycarbonate diol, the triol, the tetraol, and the catalyst, and heating the mixture with stirring at a temperature of 150 ° C. to 240 ° C. for 5 to 15 hours in a nitrogen atmosphere.

If the reaction temperature is 150 ° C. or lower, the transesterification reaction takes a long time, which is inefficient. Conversely, if the reaction is carried out at 240 ° C. or higher, by-products (such as ether compounds) are undesirably generated.

When acrylic acid or methacrylic acid is reacted with the polycarbonate polyol thus obtained, the acrylate resin or methacrylate resin of the present invention is obtained.

The reaction ratio is such that 1 mol to 10 mol of acrylic acid or methacrylic acid is reacted with 1 mol of the polycarbonate polyol.

Since the polycarbonate polyol has more than two hydroxyl groups in one molecule, when the reaction ratio is 1: 1, one of several hydroxyl groups in the molecule has an acryl group or a methacryl group. Reaction ratio 1: f (f is the number of hydroxyl groups in one molecule of polycarbonate polyol)
In the case of, acrylic or methacrylic groups are introduced into all the hydroxyl groups, and when reacted at a higher ratio, excess acrylic acid or methacrylic acid may remain in the reaction system or be removed after the reaction. Become.

If the ratio of acrylic acid or methacrylic acid is lower than the above reaction ratio, the resulting resin has extremely poor ultraviolet curability.

Conversely, when the ratio is high, acrylic acid or methacrylic acid is wasted.

The reaction can be performed under the same conditions as those for synthesizing a usual acrylic ester or methacrylic ester.

For example, a predetermined amount of a polycarbonate polyol and acrylic acid or methacrylic acid, a dehydrating azeotropic agent, an esterification catalyst, and a polymerization inhibitor are charged to a reactor equipped with a stirrer, a thermometer and a water separator, and heated while stirring. .

It is removed from the system as an azeotropic mixture with a dehydrating azeotropic agent produced by the reaction, and cooled when a predetermined amount of water is distilled off.

After the reaction solution is washed with an aqueous alkali solution and an aqueous solution of an inorganic salt, the dehydrating azeotropic agent is removed under reduced pressure. In this case, a polymerization inhibitor may be further added. The residue in the reactor is a polymerizable composition containing the desired polycarbonate poly (meth) acrylate, and is used as it is or after being purified with activated carbon, activated alumina or the like, if necessary.

As the esterification catalyst, sulfuric acid, hydrochloric acid, benzenesulfonic acid, p-toluenesulfonic acid and the like are used. As the polymerization inhibitor, hydroquinone, p-benzoquinone, p-
Tert-butyl catechol, diphenylamine thiosemicarbazite, sulfur, phenothiazine, hydroquinone monomethyl ether and the like are used.

An azeotropic dehydrating agent forms an azeotropic mixture with water, does not mix with water,
And those that are chemically stable in the reaction system are used, for example,
Cyclohexane, benzene, toluene, n-hexane,
Examples include trichloroethylene and isopropyl ether.

The reaction temperature varies depending on the type and amount of the azeotropic dehydrating agent to be used, but generally 80 to 120 ° C is appropriate.

The polycarbonate acrylate resin or polycarbonate methacrylate resin obtained by the production method of the present invention is used as a photopolymerizable prepolymer, and various polymerizable monomers, photoinitiators, sensitizers, colorants, and other additives ( Viscosity improvers, antioxidants, polymerization inhibitors,
A composition mixed with a wetting aid, a dispersant, a drying agent, etc.)
Used for paints, adhesives, optical fiber coatings, etc.

Each of them is excellent in heat and moisture resistance and curing properties (weak anaerobic).

In order to specifically explain the present invention, examples and reference examples will be given below.

Synthesis Example-1 [Synthesis of Polycarbonate Polyol] Polycarbonate diol (manufactured by Daicel Chemical Industries, Ltd .: trade name: CD220, molecular weight: 2) was placed in a 2-liter round bottom flask equipped with a stirrer, thermometer, nitrogen inlet tube, and condenser.
011, OH value 55.8 KOHmg / g) 1566.3 g (0.7788 mol), 327.7 g (2.4069 mol) of trimethylolpropane, 106.0 g (0.7900 mol) of pentaerythritol, 0.08 g of tetrabutyl titanate as a catalyst, and stirring under normal pressure. Let warm.

Gradually raise the temperature of the mixture in the flask to 220
After reaching ℃, the reaction was further carried out at 220 ℃ for 8 hours.

Sampling was performed over time during the reaction, and the remaining diol component (here, 1,6-hexanediol) and triol component (trimethylolpropane) were quantified by gas chromatography, and the transesterification reaction reached equilibrium. It was confirmed. The obtained polycarbonate polyol was a liquid having an OH value of 337.0 and a glass transition point of -70 degrees.

Example-1 [Synthesis of Polycarbonate Poly (meth) acrylate] In a four-necked flask equipped with a nitrogen inlet tube, a thermometer, a cooling tube, and a stirrer, 500 g (1.0 mol) of the polycarbonate polyol obtained in Reference Example-1 was added. 360 g of acrylic acid (5.0 mol),
5.0 g of paratoluenesulfonic acid as a catalyst, 200 g of benzene as an azeotropic dehydration solvent, and 0.7 g of hydroquinone monomethyl ether were charged into a flask, and a dehydration reaction was carried out under benzene ring distillation.

 The reaction was terminated when the distillation of water stopped.

After completion, the acrylic acid was washed off with water in a benzene / water system, and then benzene was removed under reduced pressure to obtain an acrylate resin having the following properties.

Appearance Yellow-brown liquid Viscosity (25 ° C) 5000cp Acid value 0.2 Comparative examples 1 and 2 Polycarbonate polyol in Example 1 was replaced with polyester polyol (PCL- manufactured by Daicel Chemical Industries, Ltd.).
305) and polyether polyols (Asahi Denka Co., Ltd.)
Adeka polyether G-400).

Application Examples 1 to 3 The polycarbonate polyacrylate resin obtained in Example 1 and the polyester polyacrylate resin and polyether polyacrylate resin obtained in Comparative Examples 1 and 2 are combined with a typical diluent monomer and a sensitizer, It was applied to a thickness of 15 μm and 150 μm on an iron substrate and release paper, respectively, and was irradiated with UV to obtain a cured coating film.

Using the substance applied on the iron substrate, evaluate the touch dry (measure the curing time at a constant irradiation dose by touch),
Using a sample coated to a thickness of 150 μm, heat and humidify the sample (121 ° C, RH 95%, 48 hours), and maintain the tensile strength before processing (= tensile strength after processing / tensile before processing) (Strength x 100) was evaluated.

 Table 1 shows the results.

Claims (1)

(57) [Claims] 1. A polycarbonate polyol is produced by subjecting a polycarbonate diol to a transesterification reaction with a trifunctional or higher polyfunctional polyol, and all or a part of the hydroxyl groups of the obtained polycarbonate polyol is reacted with acrylic acid or methacrylic acid. A method for producing a polycarbonate acrylate resin or a polycarbonate methacrylate resin, characterized by comprising: