JPH01123813A - Diluent for radiation-curable resin - Google Patents

Abstract

PURPOSE:To obtain the subject diluent which can give a coating film having a high curing rate, a low curing shrinkage and improved elongation, by reacting a (poly)hydroxy compound with an acrylic acid (lower alkyl ester). CONSTITUTION:A (poly)hydroxy compound is esterified or transesterified with an acrylic acid or a lower alkyl ester thereof in the presence of an acid or basic catalyst and a polymerization inhibitor in an azeotropic solvent to obtain a diluent for radiation-curable resin, comprising a compound of the formula [wherein R is -O- or R1-(O)q-, R1 is a 1-20C hydrocarbon group, O is an oxygen atom which is bonded to C constituting R1, q is 1-8 and is a number corresponding to p, n and m are each 1-3, p is 1-8, R' is CH3 or C2H5, and R'' is H or CH3] and having an MW per (meth)acryloyl group [the entire MW/the number of the (meth)acryloyl groups] of 150-360.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Yf) The present invention relates to a diluent for radiation-curable resins containing oligomers.

(Prior Art) Acrylic esters conventionally used as diluents for radiation-cured resins include, for example, tetrahydrogofurfuryl acrylate, 2-phenoxyethyl acrylate, nonylphenoxy polyethoxylated acrylate, ethyl cellosolve acrylate, Monoacrylates such as nonyl acrylate and isodecyl acrylate; 1.
Diacrylates such as 6-hexanediol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, bisphenol A polyethoxylated diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, trimethylolpropane polypropoxylated triacrylate, etc. Multiacrylates such as triacrylates and dipentaerythritol hexaacrylate are known.

(Disadvantages of the Prior Art) Acrylic esters conventionally used as diluents for radiation-curing resins have the performance required as a diluent for radiation-curing resins, that is, low viscosity.

There are few products that can satisfy the performance requirements such as low skin irritation, fast curing speed, and little curing shrinkage, and there are also few products that can be used at a price that can be used on a practical level.

For example, trimethylolpropane triacrylate is known as the most widely used compound.Although this compound has low viscosity and no problems in terms of curing speed, it is highly irritating to the skin and has a fast curing speed of 6. The resin after curing has a large curing shrinkage, and the cured resin has little elongation, so although it can be used as a component of the resin, it has the problem that it is difficult to use as a main raw material.

(Means for Solving the Disadvantages) The present invention has been made to address these conventional problems. In other words, by taking advantage of the fast curing speed of the polyalkylene ether structure, and as a result of intensive study on its conductor, we found that: It is characterized by containing as an essential component a compound having a molecular weight [(total molecules M)/(number of (meth)acryloyl groups)] of 150 to 360 [hereinafter referred to as a compound represented by general formula (1)]. This has led to the provision of a diluent for radiation-cured resins.

... (1) [Requirements constituting the means] For the radiation-curable resin of the present invention! The compound represented by the general formula (1) used as a tl translator is a compound obtained by an esterification reaction or transesterification reaction between a (polyhydric) hydroxy compound and acrylic acid or lower alkyl acrylic ester, and (meth) ) Molecular weight per acryloyl group [(total molecular weight)/((meth)acryloyl large side 1
! ! > ] is 150 to 360.

- If the molecular weight per (meth)acryloyl group [(total molecular weight)/(number of (meth)acryloyl groups)] of the compound represented by pattern hole (1) is in the range of 150 to 360, the curing speed is It sufficiently satisfies the requirements from a practical use level, and furthermore, its structure greatly contributes to improving the physical properties of the coating film.

Esterification or transesterification is carried out by a known method, ie, in the presence of an acid or base catalyst, in an azeotropic solvent, under conditions containing a formalization inhibitor, and then the catalyst and molten core are removed.

Examples of the (polyhydric) hydroxy compound include compounds obtained by subjecting a (polyhydric) alcohol, (polyhydric) alkylphenol, or ethylene glycol to an addition reaction with ethylene oxide, and further with propylene oxide.

The (polyhydric) alcohols or (polyhydric) phenols mentioned here include methanol, ethanol, isopropyl alcohol, phenol, propanediol, butanediol, bisphenol A, neopentyl glycol, trimethylolpropane, glycerin, trimethylolethane, penta Erythritol, dipentaerythritol,
Examples include diglycerin, nrubitol, and sucrose.

In addition, ethylene oxide,
When propylene oxide is added, it is carried out in the presence of an acid or basic catalyst according to a conventional method. Preferably, in order to narrow the molecular weight distribution, ethylene oxide is added and then distilled to increase purity. , propylene oxide is subjected to an addition reaction.

Incidentally, as a similar substance to the compound represented by the general formula (1) of the present invention, there may be mentioned a compound having the following structure (hereinafter referred to as compound-a). The difference from the compound represented by the general formula (1) of the present invention is the purity from the standpoint of industrial production method and the degree of difficulty in obtaining a highly purified product. Excellent in that respect.

(a) In other words, high purity means that it does not contain by-products with lower molecular weight, and in general, low molecular weight fil (meth)acrylic acid esters are highly irritating to the skin, so high purity is required. Cheng,
Skin irritation is reduced.

In particular, it is known that the addition of alkylene oxide is a sequential reaction and produces a monomolecular weight distribution, and there is a background in which many by-products are likely to be produced.

In general, the compound after (meth)acrylic acid esterification is unstable and difficult to purify by distillation, so it is common to refine it by distillation at the intermediate stage to increase its purity.

However, in the case of the compound represented by the general formula (1) of the present invention, as mentioned above, it is an addition of alkylene oxide, and the molecular weight distribution becomes wide, making it difficult to improve the purity. Therefore, in order to achieve higher purity, a two-stage alkylene oxide addition reaction is carried out, but it is advisable to carry out distillation purification in the first addition stage.

When the compound represented by the general formula (1) of the present invention is compared with Compound A in consideration of the above, the following can be said.

For example, the so-called present invention (7
) [In case of RO+ CHz CH20hm-H O
H is primary OH, and R' ■ R-0+ CH2 (:R20CHn-+C■2 (HO+
m-H(1) DH is a secondary OH, and due to the difference in its reactivity, RO+CI after addition of propylene oxide
The remaining 20H20+n-H is 1.15 mol of propylene oxide/RO+ CH2--CH20)+1-
By reacting 81 moles, almost all of the atmosphere is obtained.

However, in the case of the raw material for compound -i, in which RO)l is reacted with propylene oxide and then ethylene oxide, R'R1) + CH2G)10)m-H, which is produced by reacting propylene oxide, is distilled and purified by analogy. Even so, the OH of R' R-0+ CH2CHO + Peng-H is secondary OH, and R' R-0 ÷ CH2 (: HO + m − + cHz CH20
+n-H(1) OH is primary OH, and the addition reactivity of alkylene oxide is.

Since primary OH>secondary OH, in order to reduce the amount of R'R-0+ CH2CHOTE■-H remaining after the second stage ethylene oxide reaction to zero,
Ethylene oxide requires 2.0 moles of R'/1 mole of R-0-f CH2CHO), which has the disadvantage that the molecular weight distribution becomes extremely broad.

As a result, Compound-I has a large average molecular weight and a wide molecular weight distribution, which is undesirable because the curing speed with radiation is slow.

The radiation-curable resin according to the present invention includes oligomers, diluents (
diluent monomer), various additives 1, such as pigments, matting agents, wax, and if necessary, a photopolymerization initiator, and by irradiation with radiation such as ultraviolet rays, electron beams, plasma, X-rays, and γ-rays. The diluent of the present invention is used as a diluent or diluent monomer in the above formulation.

In addition, the term oligomer used here refers to, for example, urethane (meth)acrylate produced by a urethane reaction, an epoxy compound and (meth)acrylic acid, or an active hydrogen-containing (meth)acrylate.
Epoxy acrylates produced by reaction with acrylic esters, polyester acrylates produced by reaction of polyester polyols with acrylic acid or acrylic acid lower alkyl esters, etc. The compound of the present invention can be used in combination with any of them.

(Effects of the Invention) The compound represented by the general formula (1) of the present invention is used as a component of radiation-curable resins as a diluent for radiation-curable resins, and is similar to the conventionally known compounds of the present invention. Compared to compounds such as (meth)acrylic acid esters of polyethylene oxide adducts, in practical use, the curing speed is faster, the cure shrinkage of the coating film is less, and the physical properties of the coating film, such as the elongation of the cured film, are significantly improved. , which provides excellent effects.

(Example) Examples will be described below, but the present invention is not limited to the following examples.

In the examples, parts and percentages are based on weight.

(Synthesis Example 1) 276 g (2 m
Place Ig of sodium methylate (28% methanol solution) in a 500 m cubic volume autoclave, heat to 80°C, and remove methanol at 50 mmHg.
Heat to 30°C and add 140 g of propylene oxide (
2,41 m o n ) was gradually added and reacted.
The temperature during the reaction was maintained at 135±5°C, and the autoclave pressure at that time was:

Set it to a maximum of 4kg/cm2.

After the reaction, the reaction solution is neutralized using phosphoric acid. Adjust P)1 of the reaction solution after neutralization to 6.5 to 7.5. The amount of orthophosphoric acid required for neutralization was 0.3 g. The yield of the propylene oxide adduct of 2-hydroxyethylphenyl ether thus obtained was 416 g.

When this was analyzed by gas chromatography, unreacted 2-
No residual hydroxyethylphenyl ether was observed.

Moreover, the hydroxyl value was 270.

Next, 208 g of the obtained propylene oxide adduct of 2-hydroxyethyl phenyl ether was placed in a glass flask, and 300 g of toluene, 6 g of p-)luenesulfonic acid, 0.5 g of hydroquinone, and 103 g of methacrylic acid were added. The reaction was carried out by heating while blowing.

Water generated in the reaction was removed from the system.

The reaction temperature was 110 to 120°C, and the amount of dehydrated water at the end of one reaction was 18.6 g.

After the reaction, after washing with alkaline water and washing again with water, the upper toluene layer was separated, and the toluene was distilled off to obtain 2, which is represented by the following formula.
- 235 g of propylene oxide adduct methacrylic acid ester of hydroxyethylphenyl ether (yield: 8
5%).

The obtained compound had a viscosity of 15 cp (25°C) and a saponification value of 204.

butylene oxide 3
37 g (4.68 m on) was added to body temperature. The yield was 547 g, and no residual diethylene glycol was detected by gas chromatographic analysis. Moreover, the hydroxyl value was 409.

Next, 274 g of the diethylene glycol/butylene oxide adduct obtained, 300 g of benzene, 10 g of phenolsulfone M, 0.8 g of hydroquinone, 1 g of acrylic acid.
80g was placed in a glass flask and reacted at a reaction temperature of 80-90°C while blowing air, and purified in the same manner as in Synthesis Example (1) to obtain diethylene glycol-butylene oxide adduct acrylic ester 33 shown by the following formula.
6 g (88% yield) was obtained.

The obtained compound had a viscosity of 20 cp (25°C), a saponification number of 293, and a bromine number of 83.5.

Formula % Formula % Glycerin triethylene glycol ether J Shikari distilled product, purity 99.0%) 224g (1m).

! ;L) was carried out in the same manner as in Synthesis Example (1), and 260 g (3.6 mo) of propylene oxide was gradually subjected to an addition reaction. The yield was 483 g, and no residual glycerin triethylene glycol was detected by gas chromatographic analysis. Also, the hydroxyl value is 3
It was 48.

Next, 300 g of the obtained glycerin-triethylene glycol ether propylene oxide adduct, 300 g of benzene, 10 g of P-)luenesulfonic acid, 1.0 g of hydroquinone, and 175 g of acrylic acid were placed in a glass flask and reacted in the same manner. .

Purified in the same manner as in Synthesis Example '(1), 340 g of glycerin triethylene glycol ether φ propylene oxide adduct acrylic ester represented by the following formula (yield: 8
5%).

The obtained compound had a viscosity of 25 cp (25°C), a saponification number of 261, and a bromine number of 74.

Fifty 112 + Otori, =
4.48 (Synthesis Example 4) Nrubitol poly(n=10) ethylene glycol ether (undistilled product, hydroxyl value 541) 311 g
Propylene oxide 244g (4.2moi) was prepared in the same manner as in Synthesis Example (1) except for using (0.5moJl).
were subjected to gradual addition reactions. The yield was 552g. Further, the hydroxyl value of the sorbitol φ poly(n=10) ethylene glycol ether propylene oxide adduct was 303.

Next, (sorbitol-based poly(n=10) ethylene glycol ether propylene oxide adduct 33
3g, benzene 300g, phenolsulfonic acid log
, 2 g of hydroquinone, and 168 g of acrylic acid were placed in a glass flask and reacted in the same manner.

Sorbitol poly(n=lO) ethylene glycol ether propylene oxide adduct acrylic ester 3 was purified in the same manner as in Synthesis Example (1) and shown by the following formula.
57 g (yield: 83%) was obtained.

The viscosity of the obtained compound was 35 cp (25 °C),
The saponification number was 234 and the bromine number was 66.5.

Formula % Formula % 1 + m 2 + m s
=8.4 (Examples 1 to 5) Paints were prepared from the (meth)acrylic acid esters synthesized in Synthesis Examples 1 to 4 according to the treatments shown in Table 1, and radiation & a curing was performed.

Table 1 shows the curing speed and physical properties of the cured product.

Example (1) and Comparative Example (1), Example (2) and Comparative Example (
It is structurally similar to 2), and as is clear from the comparison, it is recognized that the material of the present invention has a fast curing speed and good elongation of the cured product.

Claims (1)

[Scope of Claims] Molecular weight per (meth)acryloyl group represented by the following general formula (1) [(total molecular weight)/((meth)
A diluent for radiation-curable resins, which contains as an essential component a compound having an acryloyl group number of 150 to 360. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) [In the formula, R is -O- or ▲There are mathematical formulas, chemical formulas, tables, etc.▼. ▲There are mathematical formulas, chemical formulas, tables, etc.▼, R_1 is a hydrocarbon group having 1 to 20 carbon atoms, and O is R
means the oxygen that forms an ether bond with the carbon that constitutes _1,
q is a number from 1 to 8 and corresponds to p. n is 1
-3, m is a number from 1 to 3, and p is a number from 1 to 8. R
' is CH_3 or C_2H_5, R″ is H or C
It is H_3. ]