WO2008098414A1

WO2008098414A1 - Polyfunctional benzophenone derivates and uses as photoinitiators thereof

Info

Publication number: WO2008098414A1
Application number: PCT/CN2007/000484
Authority: WO
Inventors: Peng Luo; Wenchao Zhao; Lili Jiang; Lixiu Yao; Ronghui Hao; Qingjin Yan
Original assignee: Insight High Technology Co., Ltd.
Priority date: 2007-02-12
Filing date: 2007-02-12
Publication date: 2008-08-21

Abstract

Compounds of formula (I) and compositions comprising two or more such compounds: in which: m is 0 or 1; n is an integer from 0 to 4; y is independently each other selected from 1 or 2; R1, R2, R3, R4 are independently each other selected from H, -CH3 or -CH2CH3, with the provision that R1, R2, R3, R4 are not all represent H; The said compounds or compositions can be used as photo initiators in photo curable liquid composition.

Description

Polyfunctional benzophenone derivatives and their use as photoinitiators

This invention relates to a class of benzophenone derivatives. These derivatives are useful as photoinitiators, particularly as photoinitiators in photocurable varnishes, printing inks and the like. The invention also provides a photocurable composition comprising at least one of the compounds of the invention as a photoinitiator. Background technique

Photoinitiators for varnish formulations require good cure speeds, especially good surface cure activity, low odor, low yellowness and good solubility. In addition, as consumers become increasingly sensitive to foreign compound contamination in food, the tendency to migrate compounds and dissolve in external media should be as small as possible in order to comply with future legislative requirements. It is increasingly difficult to meet the above requirements with commercially available commercial photoinitiators.

Currently, benzophenone is still one of the most widely used photoinitiators for ultraviolet (UV) cured overprint varnishes because of its good surface cure, high solubility, and low cost, and easy availability. However, benzophenone has a strong odor and is extremely easy to migrate out of the print and dissolve into the food.

It is well known that macromolecularized benzophenone derivatives can produce products which are low in odor, are not prone to migration and are not easily extracted, but these products have the disadvantages of low active ingredient content and low reactivity per unit weight, which in turn leads to Lower curing speed.

The unit weight reactivity of the photoinitiator is extremely important in photocuring. It has been found that if a photoinitiator is less reactive than benzophenone, the amount of initiator can be increased to a limited extent to maintain the cure speed of the formulation. However, after the concentration of the photoinitiator exceeds 10 to 12%, the non-acrylate functional material either exhibits the property of a plasticizer or lowers the crosslinking density of the cured film, resulting in an effect on its mechanical properties.

It can be seen that the cured coating with high functionality, good solubility in the coating formulation, high reactivity, and very low odor, migration and extraction tendency is much lower than most existing benzophenone compounds. There is a real need for photoinitiators. Summary of the invention

The present invention provides a compound of the formula (I):

among them,

m is 0 or 1·,

η is an integer of G-4, preferably an integer of 0-2;

y each independently selected from 1 or 2;

1^, 11 ₂ , 11 ₃ , 11 ₄ are each independently selected from 8, - CH ₃ or - CH ₂ CH ₃ , but are not H at the same time. In view of convenience and economy, a mixture of compounds conforming to the formula (I) is often used in practice. Accordingly, the present invention also provides a composition characterized in that the composition contains two or more compounds of the formula (I).

In addition, the invention also provides the use of a compound of formula (I) as a photoinitiator. Further, the present invention provides a photocurable liquid composition comprising the following components:

A polymerizable component comprising at least one ethylenically unsaturated monomer or oligomer; a compound of the formula (I) of the present invention or the above composition containing the compound of the formula (I). The present invention also provides a process for preparing a cured polymer by subjecting the photocurable liquid composition of the present invention to light radiation, such as ultraviolet light.

The compound of the formula (I) of the present invention overcomes the drawbacks of benzophenone and other existing photoinitiators, has an extremely low odor, has high solubility in an ultraviolet light-curing formulation composition, and has a low tendency to migrate and be dissolved by an external medium. advantage. Moreover, its unit weight reactivity is almost equivalent to benzophenone itself. In most cases, its reactivity is higher than the commonly used benzophenone substitutes. detailed description

In the formula (I) of the present invention, the oxygen atom attached to the phenyl group of the benzophenone may be bonded to any position of the phenyl group. In view of the availability of the starting materials and the convenience of synthesis, it is preferred that the oxygen atom is bonded to the ortho or para position relative to the carbonyl group. The difference in the position of the attachment has no substantial effect on the properties of the compounds of the invention, especially as the nature of the photoinitiator.

In the compound of the formula (I) of the present invention, R ₃ is a branched chain Preferred is 2-mercapto-1, 3-propanediol, 2,2-dimethyl

a residue of -1,3-propanediol (neopentyl glycol), 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, preferably m and n Both are 0, y is 1 , is -01 ₃ , R ₂ is H or a CH ₃ ; or m, n and y are 1, ! ^ and R ₃ are - CH ₂ CH ₃ , R ₂ and R ₄ are H; or m and n are both 0, y is 2, and -( 11 ₃ , R ₂ is H.

2, 2-dimercapto-1, 3-propanediol, 3-methyl

-1 , a residue of 5-pentanediol, 2,4-diethyl-1, 5-pentanediol.

In the present specification, "residue of alcohol" refers to a group remaining after the alcohol loses its hydroxyl group. For example, the residue of neopentyl glycol is H ₃ C Η ₃ .

— H ₂ C— C- CH ₂ —

The compounds of the present invention can be prepared by a conventional method for preparing an ester compound, and the specific synthesis route and reaction conditions selected depend on the compound to be produced.

For example, the compound of the present invention can be obtained by a compound of the formula ( Π Α ) or formula ( Π Β )

Prepared by esterification, wherein m, n and y are determined

Same as above.

The reaction is preferably carried out in the presence of a solvent. The nature of the solvent is not critical to the invention as long as it does not adversely affect the reagent or reaction. Suitable solvents include: alkanes such as cyclohexane, etc.; aromatic hydrocarbons such as benzene, toluene or dinonylbenzene.

The reaction is preferably carried out in an acidic catalyst such as a sulfonic acid (for example p-toluenesulfonic acid or sulfonic acid), a mineral acid (for example, acid, hydrochloric acid or polyphosphoric acid) or a Lewis acid (for example boron trifluoride or organic titanate). In the presence of ).

The reaction temperature can be varied within a relatively wide range depending on the conditions of the reaction and the nature of the reagents and the solvent, as long as the temperature is high enough to remove water generated during the reaction, thereby ensuring completion of the reaction. We have found that it is generally preferred to carry out the reaction at temperatures near the reflux temperature of the reaction mixture. The time required for the reaction can also vary over a considerable range, depending mainly on the reaction temperature. Under the above preferred conditions, usually only need to react 2 to 20 hours.

After the completion of the reaction, it may be subjected to a post-treatment by a usual method, for example, washing the mixture with water and/or alkali water, drying, and then evaporating the solvent under reduced pressure to give a product. The solid product can be crystallized from a suitable solvent.

The compounds of the invention are particularly suitable for use as photoinitiators. A compound of the invention or a mixture of two or more of the compounds of the invention may be used alone in a photocurable varnish or ink. In addition, they can be used in many other photocurable liquid compositions.

The photocurable liquid composition employing the compound of the present invention typically comprises at least one ethylenically unsaturated monomer and/or oligomer and a compound of formula (I) according to the invention, and may optionally further comprise a reactive diluent. In the case of printing inks, the composition also includes a colorant, i.e., a pigment. The radiation curable monomer or oligomer is preferably an ethylenically unsaturated compound, typically an olefin oligomer or an acrylate monomer. Suitable acrylate oligomers include: aliphatic or aromatic acrylic acid amino phthalates, polyether acrylates, polyester acrylates and epoxy acrylates (e.g., outer bismuth A epoxy acrylate). Suitable acrylate monomers include: hexanediol diacrylate, trimethylolpropane triacrylate, bistrihydroxydecylpropane tetraacrylate, dipentaerythritol pentaacrylate, polyether acrylate (eg ethoxylated) Trimethylolpropane triacrylate, glycerol propoxy triacrylate, ethoxylated pentaerythritol tetraacrylate, and epoxy acrylate (such as Cytec's Ebcryl 150), and diol diacrylate ( For example, tripropylene glycol diacrylate).

Meanwhile, the photocurable composition of the present invention preferably contains at least one synergist such as an amino acrylate or a dimethylamino benzoate. In the case of printing inks, the synergist is preferably dimethylaminobenzoate. In the case of varnish, the synergist is preferably an amino acrylate. Some inks, such as inks for flexographic printing, may contain two different types of synergists as described above.

The amount of photocurable monomer or oligomer, photoinitiator, synergist, and optional colorant will vary depending on the type of varnish or ink, the particular equipment used for coating, and the use, which is the skill in the art. Well known to the person, or can be determined by simple experimentation according to the specific application. Usually the photoinitiator is used in an amount of from 2 to 20% by weight based on the total weight of the composition.

When the compound of the formula (I) is used as a photoinitiator in a varnish or an ink, in addition to the above-mentioned components, a pigment, a wax, a stabilizer, a rheology aid and the like are usually contained.

The invention is further illustrated by the following non-limiting examples. The sources of the raw material compounds used in the following examples are shown in Table 1.

Table " "~

Comparative example

179. 2克 (0.7 mol) 4-carboxymethoxydibenzophenone and 87· ⁵ g (0.35 mol) polytetrahydrofuran (average molecular weight 250, n in the formula 约为 is about ^3.5 ) placed in ²⁵⁰⁰ ml of azeotropically containing 3.0 g of p-toluenesulfonic acid catalyst in toluene was refluxed for 11 hours. The solution was then washed twice with 500 ml of 0.1 M aqueous sodium hydroxide solution and twice with 500 liters of deionized water. After the solution was dried by azeotrope, the solvent was removed in vacuo to give a compound of formula (m): 244. 6 g.

( I -1A )

Take a 500 ml four-necked bottle and convert 51.3 g (0.20 mol) of the above formula (Π A ) The compound, 10.4 g (0.10 mol) of neopentyl glycol and 1.6 g of p-toluenesulfonic acid catalyst were placed in 250 ml of toluene and azeotropically refluxed for 10 hours. The reaction solution was added to 100 ml of an aqueous solution containing 2.0 g of sodium hydrogencarbonate, stirred at room temperature for 0.5 hour, the aqueous phase was separated, and the upper toluene solution was washed twice with 200 ml of deionized water. Then, the solution was refluxed and water was separated by a water separator, and toluene was removed on a rotary evaporator to obtain 55.4 g of a compound of the formula (I-1A) as a pale yellow viscous substance, yield 95.4%.

¹匪R (δ, ppm): 0.92 (s, 6H, CH ₃ ) , 3.96 (s, 4H, CH ₂ ), 4.73 (s, 4H, 0CH ₂ ), 6.95 (d, Ar-), 7.46 (t , Ar-), 7.57 (t, Ar -), 7.75 (d, Ar -), 7.83 (d, Ar-:). Example 2

Take a 500 ml four-necked flask, 51.2 g (0.2 mol) of the compound (Π A), 16.03 g (0.1 mol) of 2,4-diethyl-1,5-pentanediol and 1.6 g of p-toluenesulfonic acid catalyst It was placed in 120 ml of toluene for azeotropic reflux for 10 hours. The reaction solution was added to 100 ml of an aqueous solution containing 2.0 g of sodium hydrogencarbonate, stirred at room temperature for 0.5 hour, and the aqueous phase was separated, and the upper toluene solution was washed twice with 200 ml of deionized water. Then, the solution was refluxed and water was separated by a water separator, and toluene was removed on a rotary evaporator to obtain 61.21 g of a compound of formula (I - 2A) as a pale yellow viscous material, yield 96.2%.

1匪R ( δ, ppm): 0.86 ( m, 6H, CH ₃ ) , 1.18 (m, 4H, CH ₂ ),

1.31 (m, 2H, CH ₂ ), 1.68 (m, 2H, CH), 4.09-4.136 (m, 2H, CH ₂ 0 ), 4.72 (s, ArOCH ₂ ), 6.9 (d, Ar-), 7.47 ( t, Ar-), 7.57(t, Ar-) , 7.74 (d, Ar-), 7.81(d, Ar-) ₀

Take a 500 ml four-necked flask and place 54 g (0.21 mol) of the compound (ΠA), 11.8 g (0.1 mol) of 3-mercapto-1, 5-pentanediol, and 2 g of p-toluenesulfonic acid catalyst in 250 Azeotropic reflux was carried out for 10 hours in ml of toluene. The reaction solution was added to 100 ml of an aqueous solution containing 2.0 g of sodium hydrogencarbonate, stirred at room temperature for 0.5 hour, the aqueous phase was separated, and the upper toluene solution was washed twice with 200 ml of deionized water. Then, the solution was refluxed, and water was separated by a water separator, and toluene was removed on a rotary evaporator to obtain 56.55 g of a compound of the formula (I-3A) as a pale yellow viscous material, yield 95.1%.

¹匪R ( δ, ppm): 0.928, 0.948 (d, 3H, CH ₃ ) , 1.485-1.613 (s, H, CH ) , 1.485-1.746 (m, 4H, 2 C-CH ₂ -C) , 4.183 -4.303 (m, 4H, 2 x

-CH ₂ O), 4.70 (s, 4H, 2 x ArOCH ₂ ) , 6.9 (d, Ar-), 7.47 (t, Ar-), 7.57 (t, Ar-), 7.74 (d, Ar-), 7.81 (d, Ar-).

Example 4

Take a 500 ml four-necked bottle and place 65 g (0.25 mol) of the compound (Π A), 11 g (0.12 mol) of 2-methyl-1,3-propanediol and 2 g of p-toluenesulfonic acid catalyst in 250 ml. Azeotropic reflux was carried out for 10 hours in toluene. The reaction solution was added to 100 ml of an aqueous solution containing 2.0 g of sodium hydrogencarbonate, stirred at room temperature for 0.5 hour, and the aqueous phase was separated, and the upper toluene solution was washed twice with 200 ml of deionized water. Then, the solution was refluxed and the water was separated by a water separator, and toluene was removed on a rotary evaporator to obtain 64.46 g of a compound of the formula (I-4A) as a pale yellow viscous material, yield 94.8%.

^J HNMR ( δ , ppm): 0.946, 0.969 (d, 3H, CH ₃ ) , 2.193-2.256 (m, H, CH ), 4.079-4.179 (m, 4H, 2 x -CH ₂ 0), 4.73 (s , 4H, 2 x ArOCH ₂ ), 6.9 (d, Ar-), 7.47 (t, Ar-), 7.57 (t, Ar-), 7.74 (d, Ar-), 7.81 (d, Ar-) ₀

Take a 500 ml four-necked flask and azeotrope reflux for 5 hours by placing 51.3 g (0.20 mol) of the compound (、), 10.4 g (0.10 mol) of neopentyl glycol and 1.6 g of p-toluene cross-acid catalyst in 250 ml of toluene. . The reaction solution was added to 100 ml of an aqueous solution containing 2.0 g of sodium hydrogencarbonate, stirred at room temperature for 0.5 hour, and the aqueous phase was separated, and the upper toluene solution was washed twice with 200 ml of deionized water. Then, the solution was refluxed and the water was separated by a water separator, and the benzene was removed on a rotary evaporator to obtain 55.1 g of a compound of the formula (I-IB) as a pale yellow viscous substance, yield 95.0%.

'HNMR (δ, ppm): 0.92 (s, 6H, CH ₃ ), 3.96 (s, 4H, CH ₂ ), 4.80 (s, 4H, 0CH ₂ ), 7.13 (d, Ar-), 7.50 (t, Ar-), 7.62 (t, Ar-), 7.86 (d, Ar -). The properties and elemental analysis data of the obtained compounds are shown in Table 2 below.

Example 6

Curing performance comparison

The benzophenone, the products of Examples 1 to 5 and the comparative examples were used as photoinitiators, and the corresponding UV-curable varnish formulations 1-7 were prepared according to the following Table 3. Formulation component weight percentage (%) Photoinitiator 7

Amino acrylate synergist (P115, Cytec) 8

Epoxy acrylate oligomer (6210G, Changxing) 25

Polyfunctional monomer, GPTA (EM2385 glycerol tripropoxylated three 60

Acrylate, Changxing Company)

The resulting varnish formulation 1-7 was applied to a tinplate using a 10 micron bar coater and cured at a speed of 100 m/min using a 60 watt/cm medium pressure mercury arc lamp. Record the number of passes under the lamp required to obtain a good surface and complete cure. The maximum odor is 5 and the minimum is 1. The yellowness is measured by the SC-80C automatic color difference meter. The results are shown in Table 4.

Table 4

These crucibles indicate that the curing speed of the compound of the present invention is higher than that of the comparative example. The varnish cured with the compound of the present invention as a photoinitiator has a lower odor than the varnish using benzophenone as a photoinitiator. All varnishes have similar yellowness after curing.

(Note: W appearing in the chemical structure formula in this specification indicates the connection position)

Claims

Claim

1. A compound of formula (I):

among them,

m is 0 or 1;

n is an integer from 0-4;

y are each independently selected from 1 or 2;

, 1 ₂ , 11 ₃ , 11 ₄ are each independently selected from 11, -CH ₃ or -CH ₂ CH ₃ , but are not H at the same time.

2. The compound of claim 1 wherein n is an integer from 0 to 2.

3. The compound of claim 1 wherein m and n are both 0, y is 1, 1^ is -(3⁄4, R ₂ is H or -CH ₃ ; or m, n and y are both 1,! ^ and R ₃ are -CH ₂ CH ₃ , R ₂ and R ₄ are H; or both m and n are 0, and y is 2, which is -CH ₃ and 11 ₂ is H.

The compound according to any one of claims 1 to 3, wherein the oxygen atom attached to the phenyl group of the benzophenone is at the para or ortho position of the fluorenyl group of the benzophenone.

A composition comprising two or more compounds of the formula (I) according to any one of claims 1 to 4.

6. Use of a compound according to any one of claims 1-4 and a composition according to claim 5 as a photoinitiator.

7. A photocurable liquid composition characterized by comprising the following components:

a polymerizable component comprising at least one ethylenically unsaturated monomer or oligomer; a compound according to any one of claims 1-4 or a composition according to claim 5.

The photocurable liquid composition according to claim 7, wherein the composition is a varnish or a printing ink.

9. A method of preparing a cured polymeric composition comprising exposing the photocurable liquid composition of claim 7 or 8 to ultraviolet radiation.