JPH0559128A - Diluent for radiation-setting resin - Google Patents

Abstract

PURPOSE:To provide the title low-viscosity diluent of low dermal irritability, excellent in mechanical properties, also good in water resistance. CONSTITUTION:The objective diluent comprising, as the essential ingredient, a mixture of (A) 100 pts.wt. of 1,9-nonanediol diacrylate and (B) pref. 5-200 (esp. 10-120) pts.wt. of 2methyl-1,8-octanediol diacrylate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diluent for a radiation-curable resin, and more particularly to a radiation-polymerizable diluent which is used in combination with a radiation-polymerizable oligomer as a main component to enhance its workability.

[0002]

Acrylic acid esters used as diluents for radiation-curable resins have hitherto been, for example, tetrahydrofurfuryl acrylate, 2-phenoxyethyl acrylate, nonylphenoxypolyethoxylated acrylate, ethyl cellosolve acrylate, isononyl. Monoacrylates such as acrylate and isodecyl acrylate; 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, bisphenol A
Known diacrylates such as polyethoxylated diacrylates; trimethylates such as trimethylolpropane triacrylate, pentaerythritol triacrylate, trimethylolpropane polyethoxylated triacrylate; and polyacrylates such as dipentaerythritol hexaacrylate. There is.

However, these conventional acrylic acid esters are required to have properties required as diluents for radiation curable resins, namely, low viscosity, low skin irritation, rapid curing speed, low curing shrinkage, and combined use. There are few that can sufficiently satisfy all the properties desired for the diluent, such as good compatibility with the oligomer.

In particular, as the use of radiation-curable resins has expanded in recent years, the demand for water resistance has increased more than ever before, but in this respect there are still few requirements. For example, 1,6-hexanediol diacrylate is an acrylic acid ester that can contribute to improving the water resistance of a cured product and has a low viscosity and a rapid curing rate, but has the drawback of high skin irritation. The problem remains that the applications are limited.

[0005]

In view of the above situation, the present invention has a low viscosity, a low skin irritation and excellent mechanical properties.
Moreover, it is an object to provide a diluent for a radiation curable resin having good water resistance.

[0006]

BACKGROUND OF THE INVENTION The present inventor has confirmed that monoacrylates, for example, isononyl acrylate, substantially satisfy the above-mentioned problems, when proceeding with the study. However, it was concluded that the curing speed was too slow for practical use as a diluent for radiation curable resin, and it was impossible to use it as a main component including other monoacrylates.

Further, polyfunctional acrylates of triacrylate and higher have a high curing rate, but are excluded from the scope of the study because the crosslink density of the cured resin is unnecessarily increased and becomes hard and brittle. Therefore, when attention was paid to diacrylates, especially 1,9-nonanediol diacrylate, the investigation proceeded to find that diols containing 2-methyl-1,8-octanediol which is an isomer of 1,9-nonanediol It was found that the diacrylate ester is superior to the 1,9-nonanediol diacrylate alone in terms of the curing rate by radiation and the strength and elongation of the cured product. With respect to water resistance, both 1,9-nonanediol diacrylate and 2-methyl-1,8-octanediol were superior to 1,6-hexanediol diacrylate.

Based on the above findings, the present invention comprises a mixture of 1,9-nonanediol diacrylate and 2-methyl-1,8-octanediol diacrylate (hereinafter also referred to as a specific mixed diacrylate) as an essential component. The summary is a diluent for a radiation-curable resin, characterized in that it is contained as. Hereinafter, various requirements constituting the invention will be described by dividing them into items.

Mixing ratio The mixing ratio of 1,9-nonanediol diacrylate and 2-methyl 1,8-octane diacrylate constituting the specific mixed diacrylate of the present invention is 100 parts by weight of 1,9-nonanediol diacrylate. On the other hand, it is preferably 5-200 parts by weight, more preferably 10-120 parts by weight, 2-methyl-1,8-octanediol diacrylate.

Further, the above-mentioned specific mixed diacrylate,
The mixing ratio with the radiation-curable oligomer to be blended as a component constituting a usual radiation-curable resin is preferably 20 to 100 parts by weight of the specific mixed diacrylate.
It is 200 parts by weight, and more preferably 50 to 150 parts by weight.

Radiation-curable resin The radiation-curable resin which is the subject of the diluent of the present invention includes radiation-curable oligomers, diluents (diluting monomers), various additives (eg pigments, glossing agents, waxes), and if necessary. The composition comprises a photopolymerization initiator and is cured (crosslinked) by irradiation with ultraviolet rays, electron beams, plasma, X-rays or γ-rays. The diluent of the present invention is
Used as a diluent or diluent monomer in the above formulations.

The radiation-curable oligomer used in combination here is a radiation-curable functional group such as an acrylic group,
Although it is an oligomer containing a methacryl group, a vinyl ether group, etc. in its molecule, an oligoacrylic acid ester is particularly common.

This oligoacrylic ester is a urethane acrylate (having a urethane bond in the structure), a polyester acrylate (having an ester bond in the structure), and an epoxy acrylate (having an epoxy group) according to the classification of the intramolecular bonding method. There are types such as having a ring-opened bond in the structure) and polybutadiene acrylate (having a polybutadiene bond in the structure). However, the diluent of the present invention is suitable when used in combination with any of these types of oligoacrylates. Show the effect.

Use The specific mixed diacrylate of the present invention has a low viscosity and a high curing rate as a diluent for a radiation curable resin, and further has the effect of improving the water resistance of the cured product. Therefore, a product obtained by using this product as a component of a radiation curable resin is useful as a surface protective coating agent for printed wiring boards, a CD coating agent, a coating agent for optical fibers, etc. by utilizing its water resistance.

[0015]

The composition according to the present invention, which contains a specific medium-chain saturated diol acrylic ester, has a low viscosity, a low skin irritation, a fast reaction rate, and is excellent in a cured product. As a diluent for a radiation-curable oligomer, in order to impart excellent water resistance, it is effective in improving work safety and workability and imparting water resistance to a cured product.

[0016]

EXAMPLES Hereinafter, the modes and effects of the invention will be described with reference to production examples, examples and comparative examples, but the exemplification is merely for explanation and does not mean to limit the idea of the invention.

Production Example (Synthesis example of a mixture of 1,9-nonanediol diacrylate and 2-methyl-1,8-octanediol diacrylate): 1,9-nonanediol and 2-methyl-
Mixture with 1,8-octanediol (mixing ratio 65:
35) 160 g was put in a 1 L glass flask, 160 g of benzene, 1 g of sulfuric acid and 0.1 g of hydroquinone were added, and the mixture was well stirred. Add 216 g of acrylic acid to this,
When heating was started while blowing air, when the internal temperature reached around 80 ° C., an azeotropic mixture of water and benzene was distilled out. Distillate the distillate to remove only water out of the reaction system,
The reaction was stopped when 36 g of water had distilled off, and the reaction mixture in the flask was cooled to 10 ° C or lower.

Next, excess acrylic acid and sulfuric acid were neutralized with a caustic soda aqueous solution and washed with water. The benzene solution in the upper layer is heated to 50 ° C or lower under reduced pressure to remove benzene,
Target product (1,9-nonanediol diacrylate and 2-
Mixture with methyl-1,8-octane diacrylate)
245 g were obtained. Yield 91.4%.

When the composition of this target product was analyzed by gas chromatography, it was found to be 65:35 (%) as in the case of the raw material alcohol. Similarly,
1,9-Nonanediol diacrylate and 2-methyl-
What changed the mixing ratio with 1,8-octanediol diacrylate was also synthesize | combined by the same method.

Physical properties (comparison of physical properties with other acrylic acid esters): Composition of the above example and other 1,9-nonanediol diacrylate 2-methyl-synthesized in the same manner as above.
The viscosity and skin irritation of the 1,8-octanediol diacrylate mixture in comparison with other diacrylates are shown in Table 1.
Shown in.

[0021]

[Table 1]

As shown in Table 1, it can be seen that the composition of the present invention has both properties of low viscosity and low skin irritation.

Examples 1 to 4 and Comparative Examples 1 to 3. The samples of Examples 1 and 2 of the present invention were cured under the irradiation of ultraviolet rays in the coexistence of the samples of Control Examples 1 and 2 and a radiation-curable oligomer, and the physical properties of the obtained cured products were compared. The composition of the materials used for the reaction and the curing conditions are collectively shown in Table 2.

[0024]

[Table 2]

Table 2 summarizing the examples of the present invention and comparative examples
As is clear from the above, in the system using the epoxy acrylate as the radiation-curable oligomer, the curing rate (the higher the number) is higher in the system using the composition of the present invention as the diluent (Examples 1 and 2). It is larger than that of Comparative Example 1 in which NDDA alone is used as a diluent, and is excellent in both tensile strength and water resistance.

The HDDA of Comparative Example 3 is excellent in the curing rate and the tensile strength of the cured product, but is inferior in water resistance, and, as already shown in Table 1, the skin irritation is severe.
Not favorable for occupational health.

Next, even in the system using urethane acrylate as the radiation-curable oligomer, the curing rate of the composition using the composition of the present invention as the diluent (Examples 3 and 4) was NDDA alone as the diluent. The fact that the cured product is much faster than that of Comparative Example 2 and is excellent in terms of tensile strength and water resistance of the cured product is revealed.

[0028]

As explained and demonstrated above, the present invention has low viscosity, low skin irritation, and excellent mechanical properties.
Moreover, the provision of a diluent for a radiation curable resin having good water resistance can contribute to the development of the industry using a radiation curable resin and the improvement of occupational health.

Claims (1)

[Claims] 1. A diluent for a radiation curable resin, which comprises a mixture of 1,9-nonanediol diacrylate and 2-methyl-1,8-octanediol diacrylate as an essential component.