WO2004048307A1

WO2004048307A1 - Ketones photoinitiators with reactive side chains and the photocuring system thereof

Info

Publication number: WO2004048307A1
Application number: PCT/CN2003/000181
Authority: WO
Inventors: Wenchao Zhao; Qingjin Yan; Yonglin Wang; Zhenlou Zhong; Yingwu Yin
Original assignee: Insight High Technology Co., Ltd.
Priority date: 2002-11-28
Filing date: 2003-03-13
Publication date: 2004-06-10
Also published as: AU2003221292A1; CN1504448A

Abstract

The invention provides a kind of ketones photoinitiators with reactive side chains, which are represented by formula I, their preparation and photoinitiating systems containing the same. These compounds are odorless, polymerizable and water-soluble. They are suitable as photoinitiators for the free-radical polymerization of compounds with carbon-carbon double bonds, for example the acrylates compounds.

Description

Ketone photoinitiator compound with active side chain and photocuring system thereof

The present invention relates to a class of photoinitiator compounds, and in particular to a class of ketone photoinitiator compounds with active side chains. The present invention also relates to a photocuring system and an aqueous photocuring system containing the ketone photoinitiator compound with the active side chain. These compounds are odorless, polymerizable, and water-soluble. They are suitable as photoinitiators and can be used for free-radical polymerization of carbon-carbon double bond compounds such as acrylates. Background of the invention

Photocuring technology is an environmentally friendly technology in the fields of coatings, inks, adhesives and other fields. Its material body is generally composed of acryl-containing resin, polyol acrylate, and photoinitiator. It has sufficient light energy (such as ultraviolet light) It can be cured completely under the action. Compared with traditional solvent-containing systems, it has outstanding features such as solvent-free emissions, high efficiency, and energy saving, and has been applied in many fields. However, this technology still has many shortcomings, such as high odor of acrylate and residual initiator, a certain irritation, difficulty in spraying, and large film shrinkage. Therefore, people continue to carry out research, and many advances have been made so far. For example, water-based photo-curing systems combine the dual characteristics of water-based coatings without organic solvents, easy adjustment of performance, easy construction, and fast and efficient light curing. There are relatively few agents, and the existing photoinitiators are either poorly soluble or are easily lost with water volatilization. The 2-hydroxy-2-methyl-4,-(2-hydroxyethoxy) phenyl-1-acetone proposed by the inventor of the US patent US4861916 is suitable for aqueous system applications and has been commercially sold, but it is expensive. Causes higher production costs for users.

In view of the shortcomings of the prior art, the present inventors conducted intensive and detailed research and found that the new class of compounds described in the present invention has good performance. These compounds have special side chains, which make them water-soluble, polymerizable and extremely low odor. They can be used for photo-initiated free-radical polymerization of carbon-carbon double bond compounds such as acrylates. At the same time, the invention also provides their manufacturing method and application method, thus completing the invention. Summary of invention

The present invention relates to a new class of ketone photoinitiator compounds with active side chains, their manufacturing methods, and photocurable systems containing them. The present invention provides a ketone photoinitiator compound with an active side chain: a hydroxypropyl group is introduced into the para-position of the benzene ring of an α-hydroxyketone compound or benzophenone, so that the compound is water-soluble and highly soluble. Molecularization and extremely low odor; The present invention also provides a method for preparing such ketone compounds with active side chains: propylene glycol phenyl ether is used as a raw material to obtain the target through acylation reaction, bromination reaction, alkaline hydrolysis reaction and other steps. Compounds: These compounds are suitable as photoinitiators for photo-initiated free-radical polymerization of carbon-carbon double bond compounds such as acrylates. The present invention also provides a photocuring system or an aqueous photocuring system containing the ketone photoinitiator compound with an active side chain. The photoinitiator compound is water-soluble, polymerizable, and extremely low-odor. The presence of the photo-curing system or the water-based photo-curing system has good curing characteristics. Detailed description of the invention

One of the objects of the present invention is to provide a class of photoinitiators with active side chains, which have the properties of water solubility, high polymerizability and extremely low odor.

Another object of the present invention is to provide a method for preparing the compound, according to which the compound can be conveniently synthesized. Another object of the present invention is to study the application method of the compound, and to provide a photo-curing system and an aqueous photo-curing system including the compound. The following describes the compounds of the structural formula I series as photoinitiators, the preparation method of the compounds and the photocuring system using the photoinitiator compounds. The invention provides a class of photoinitiator compounds, which can be used not only in aqueous UV system formulations, but also suitable for use in 100% UV systems. At the same time, it also meets users' requirements for low odor of photoinitiators. . Not only this, these compounds can also be used as photoinitiator units for the preparation of polymerized photoinitiators. The distribution of polymerized photoinitiators in the system tends to be more uniform, odorless, and has no surface migration.

The photoinitiator provided by the present invention is a compound of formula I:

oen

among them,

!! ^ And R ₂ are each independently selected from H or CH:

Z is CR ₃ R ₄ (0R ₅ ) or phenyl;

R ₃ is H, d- ₃ alkyl or phenyl,

Is 11, or ^ alkoxy,

Or R ₃ R ₄ is one (C¾) ₅ — _;

R ₅ is H or ₃ alkyl;

X is 0 or S;

n = l or 2.

In a preferred manner,

X is 0; in another preferred way X is 0;

Z is CR ₃ R ₄ (0R ₅ ),

Among them, R ₃ is preferably ( ₃ alkyl;

R ₄ is preferably amidino;

Or R ₃ R ₄ is preferably one (C) ₅ —;

It is preferably H.

When Z is phenyl, the compound of formula I is equivalent to a benzophenone with an active side chain, so that the benzophenone-based photoinitiator can be used in an aqueous system and polymerized.

When Z is CR ₃ R ₄ (0R ₅ ), where R ₃ = R ₄ <¾ and R ₅ = H, it is equivalent to α-hydroxyketone photoinitiators with active side chains, which can be used in aqueous UV systems and 100% UV system and polymerized. Or where R ₃ is a phenyl group and is a (^ _-3 alkoxy group, and R ₅ is a (alkyl group), it corresponds to a benzoyl dimethyl ether-based photoinitiator with an active side chain.

In the prior art, the compound has not been found, its preparation method and application examples. The following are examples of some compounds synthesized by the present invention-

(1) 2-hydroxy-2-methyl-4 '_ (2-hydroxypropoxy) phenyl-1-acetone;

1-hydroxycyclohexyl-4,-(2-hydroxypropoxy) benzophenone;

(3) 2-hydroxy-2-methyl-4 '-[2- (2-hydroxypropoxy) propoxy] phenyl-1-acetone;

2-hydroxy-2-methyl-4,-(2-lightyl-1-methylethoxy) phenyl-1-acetone;

1-hydroxycyclohexyl 4 '(2-hydroxy-1-methylethoxy) benzophenone;

(6) 2-hydroxy-2-methyl-4,-[2- (2-hydroxy-1 -methylethoxy)-1-methylethoxy] phenyl-1-acetone;

(7) 4 '-(2-hydroxypropoxy) benzophenone.

The method for preparing such compounds provided by the present invention is an organic synthesis method-propylene glycol phenyl ether is used as a raw material, and α, with a side chain, are prepared through esterification reaction, acylation reaction, halogenation reaction and alkaline hydrolysis reaction. -A hydroxy ketone target compound; while some compounds, such as compound (7), do not need to be halogenated.

The crude product is further purified by distillation under reduced pressure and / or crystallization to obtain a purified target compound. For example, propylene glycol phenyl ether is used as a raw material, and esterified with acetic anhydride at reflux temperature to obtain an ester, and then an acid chloride such as isobutyryl chloride and cyclohexanoyl chloride are subjected to acylation reaction at 0-10 ° C and bromination Reaction, alkaline hydrolysis reaction, purification and other steps to prepare α-hydroxy ketone target compounds with side chains, such as 2-hydroxy-2-methyl-4,-(2-hydroxypropoxy Group) phenyl-1-acetone, 2-hydroxy-2-methyl-4,-(2-hydroxy-1-methylethoxy) phenyl-1-acetone, etc .; for another example, propylene glycol phenyl ether As a raw material, it was esterified with acetic anhydride at reflux temperature to obtain a propyl esterified product. After the propyl esterified product was acylated with benzoyl chloride, it was subjected to alkaline hydrolysis and purified to obtain 4- (2-hydroxypropoxy) benzophenone.

The present invention also provides a photocurable system comprising at least one methacrylic acid and / or acrylate compound, a prepolymer and / or a reactive diluent, and at least one of the above formula I with a reactive side chain Ketone photoinitiator compounds.

01% 〜10% ，为 0. 5% 〜5% ， They can easily dissolve in this type of photo-curing system, the ketone photoinitiator compound with an active side chain is usually added in an amount relative to the total weight of the system In a prepolymer or reactive diluent. Other known photoinitiators can be used as co-initiators in the formulation; necessary auxiliaries such as tertiary amines, pigments, etc. can be used.

As a prepolymer or reactive diluent, there must be a C = € group, especially acryl compounds are more commonly used.

The present invention also provides a photocurable aqueous system, comprising at least one aqueous methacrylic acid and / or acrylated polymer, an auxiliary agent, such as a co-initiator, an antifoaming agent, a leveling agent, etc., and at least one A ketone photoinitiator compound with an active side chain represented by Formula I. In an aqueous system, the polymer is water-soluble or water-emulsified, and its content is 10 to 85 Wt% of the entire system. In this type of aqueous photocuring system, the ketone photoinitiator compound with an active side chain is usually added in an amount of For 0.01% to 10% by weight of the polymer, preferably 0.5% to 5%, other known photoinitiators can be used as co-initiators in the formulation; necessary auxiliary agents such as tertiary amines, pigments, etc. can also be used.

Light-curing systems (including water-based light-curing systems) are commonly used in the form of coatings, inks or adhesives for the coating and printing of paper, wood, plastic, and metal surfaces. When curing, UV radiation is used, and a high-pressure mercury lamp with a wavelength range of 250 to 500 nm is preferred.

The photoinitiator compound of the present invention is superior to the existing photobow hairpin I compound in that it has water solubility, high polymerizability, and extremely low odor. Examples

The invention is further illustrated by the following non-limiting examples.

Example 1: Preparation of 2-hydroxy-2-methyl-4 '-(2-hydroxypropoxy) phenyl-1-acetone

(a) 305 g (2. Omol) of 1-phenoxy-2-propanol (2-hydroxypropyl phenyl ether) and 245 g (2.4 mol) of acetic anhydride, heated to reflux temperature of 143 ° C for 2 hours, and reduced pressure Evaporate the acetic acid and excess acetic anhydride to obtain 380 g of light yellow liquid (98% yield)

(¾) 440g (3.3mol) of anhydrous aluminum trichloride in 800ml of dichloroethane, and cooled down to -5. C, keep below 0 ° C, add 291.5g (1.5mol) 2- (1-phenoxy) propyl acetate dropwise within 1 hour, and then add 168g (1.6mol) isobutyryl chloride dropwise within 2 hours, at the same temperature Stirring was continued for 2 hours. The reaction solution was carefully poured in batches into 2.5 kg of crushed ice containing 900 ml of hydrochloric acid. The organic phase was separated, washed once with water, dried over night, and concentrated and distilled under reduced pressure. 396 g (95% yield) of 4- (2-acetoxypropoxy) phenylisobutanone was obtained. The boiling point is 150 ~ 155 ° C / 0.5mmHg. (c) 264 g (1.0 mol) of 4- (2-acetoxypropoxy) phenyl isobutyl ketone was dissolved in 500 ml of dichloroacetamidine, 100 ml of glacial acetic acid was added, and stirred, and 176 g (1.1 ml ) Liquid bromine. After stirring for 5 hours, the reaction solution was washed with water and concentrated to give 332 g of a yellow oil. Add 6g of phase transfer catalyst to the above oil, dropwise add 400g of 30% sodium hydroxide solution at 45 ° C and stir vigorously for 2 hours, add a water layer, dissolve the oil layer in 250ml of ethyl acetate, wash with water to neutrality, dry and concentrate to recover acetic acid Ethyl ester yielded 202.3 g of a crude yellow oil, which was decolorized and recrystallized with ethanol to give 143 g of 2-hydroxy-2-methyl-4,-(2-hydroxypropoxy) phenyl-1-acetone as a white powder. Rate of 60%). Melting point 76 ~ 79 ° C; Elemental analysis results: C 65. 25% (theoretical value 65. 52%), H 7. 70 (theoretical value 7. 61%); UV absorption spectrum λ max275. 5nm.

NMR hydrogen spectrum data: δ 8. 07-6. 94 ppm two groups (benzene ring 4H); δ 4. 26-4. 19 ppm multiplet (CH); δ 4. 03-3. 86 two groups (CH2); δ 1. 63 singlet (2CH3); δ 1. 30, 1. 28 doublet (CH3)

(d) The crude product was collected by distillation under reduced pressure at a temperature of 180-185 ° C / 60Pa to obtain a nearly colorless liquid, which became a white solid after condensation. The analysis results are the same as (c).

Example 2: 2-¾ "2-methyl ¾" 4,-(2-¾ "1-methyl

Using 2-phenoxy-1-propanol as a raw material, the synthesis method was the same as in Example 1 to obtain a crude product under reduced pressure distillation, collected at 180-185 ° C / 60Pa, and condensed into a viscous liquid. NMR hydrogen spectrum data: δ 8. 07-6. 95ppm two groups (benzene ring 4H); δ 4. 68-4 · 58ppm sixfold peak (CH)

δ 3. 79, 3. 77 doublet (CH2); δ 1. 63 singlet (2CH3); δ 1. 38, 1. 36 doublet (CH3) Example 3: 4 '-(2-hydroxypropoxy) Preparation of benzophenone

(a) 440g (3. 3mol) of anhydrous aluminum trichloride in 800ml of dichloroethane with stirring to cool down to-5 ° C, keep below 0 ° C, add 291.5g (1.5mol) acetic acid dropwise within 1 hour 2- (1-phenoxy) 1 propyl ester, and then 225 g (1.6 mol) of benzoyl chloride was added dropwise over 2 hours, and stirring was continued at the same temperature for 2 hours. The reaction solution was carefully poured in batches into 2. OKg crushed ice containing 900 ml of hydrochloric acid. The organic phase was separated, washed once with water, dried over night, and concentrated to obtain 425 g (yield 95%) of 4- (2-acetoxypropoxy) benzophenone.

(b) 150 g (0.5 mol) of oil is added with 3 _g of a phase transfer catalyst, and 100 g of 30% sodium hydroxide solution is added dropwise and stirred vigorously for 2 hours at 45 ° C or less, a water layer is added, and the oil layer is dissolved in 250 ml of ethyl acetate, and washed To neutrality, dry and concentrate to recover ethyl acetate to obtain 115.3 g of crude light yellow oil. Decolorize and recrystallize with ethanol to obtain 102 g of 4- (2-hydroxypropoxy) benzophenone as a white solid (yield 80%). ). 3 ° C。 Melting point 66. 5 ~ 68. 3 ° C.

Elemental analysis results: C 74. 17% (theoretical value 74. 98%), H 6. 34 (theoretical value 6. 29%); UV absorption spectrum λ max288. 5nm. NMR hydrogen spectrum data: δ 7. 85-6. 96ppm five groups (two benzene rings 9H); δ 4. 28-4. 21ppm multiplet (CH); δ 4. 04-3. 86ppm two groups (CH2); δ 2. 308, 2. 296 ppm doublet (OH); δ 1. 33, 1. 31 ppm doublet (CH3)

Example 4: UV curing of varnishes

46 parts polyurethane acrylate (EB264, UCB), 16 parts epoxy acrylate and

In 30 parts of HDDA system, 5 parts of 2-hydroxy-2-methyl-4 '-(2-hydroxypropoxy) phenyl-1_acetone and 3 parts of triethanolamine were added.

Apply a film of 40 m on the glass plate, use a high-pressure mercury lamp (80w / crri, distance between the test plate and the lamp 20cm), the surface is slightly sticky in 45s, and it is completely cured in 60s. The cured film is transparent without yellowing, and there is no residual odor.

Example 5: UV curing of varnishes

46 parts polyurethane acrylate (EB264, UCB), 16 parts epoxy acrylate and 30 parts HDDA, 5 parts 2-hydroxy-2-methyl-4,-(2-hydroxy-1-methyl (Ethoxy) Phenyl-1-acetone, 3 parts triethanolamine.

Apply a 40 μm film on the glass plate, use a high-pressure mercury lamp (80 _W / cm, the distance between the test plate and the lamp is 20 cm), the surface is slightly sticky for 45 seconds, and it is completely cured in 60 seconds. The cured film is transparent without yellowing, and there is no residual odor.

Example 6: UV curing of varnishes

46 parts of polyurethane acrylate (EB264, UCB), 16 parts of epoxy acrylate and 30 parts of HDDA were added to 5 parts of 4- (2-hydroxypropoxy) benzophenone, and 3 parts of triethanolamine.

Apply a film of 40 μm on the glass plate, use a high-pressure mercury lamp (8 (k / cm, distance between the test plate and the lamp 20cm)), the surface is slightly sticky in 45s, and it is completely cured in 60s. The cured film is transparent without yellowing, and there is no residual smell.

Example 7: UV curing of printing inks

16 parts polyurethane acrylate (EB264, UCB), 46 parts epoxy acrylate and

Add 30 parts of HDDA to 5 parts of 2-hydroxy-2-methyl-4,-(2-hydroxypropoxy) phenyl-1 -acetone, 3 parts of triethanolamine, and 8 parts of phthalocyanine blue (7072FR, BASF the company).

The film was coated on a glass plate with a thickness of 2 μm, and a high-pressure mercury lamp (80w / cm, the distance between the test plate and the lamp was 20cm) was used. The surface was slightly sticky in 60s and completely cured in 90s.

Example 8: UV curing of aqueous systems

100 parts of solid content 30% water-based polyurethane acrylate, 0.3 parts of 2-hydroxy-2-methyl-4,-(2-hydroxypropoxy) phenyl-1-acetone can be quickly dissolved, plus 0.2 Parts triethanolamine,

Apply 45 μm film on the glass plate and dry 16 μm film. Use a high-pressure mercury lamp (80w / cm, the distance between the test plate and the lamp is 20cm), the surface is slightly sticky in 25s, and it is completely cured in 48s. The cured film is transparent without yellowing, and there is no residual odor.

Example 9, Example 10: UV curing of aqueous system

Using the method of Example 8, the experimental results using compounds (4) and (7) as the initiator are as follows Table 1 shows: Table 1

Comparative Example 1: UV curing of varnish The 2-hydroxy-2-methyl-4 '-(2-hydroxypropoxy) phenyl-1-acetone in Example 4 was replaced with Darocur 2959, and the same curing operation was performed. 45s surface is slightly sticky, 60s is completely cured. Comparative Example 2: UV curing of an aqueous system

The 2-hydroxy-2-methyl-4 '-(2-hydroxypropoxy) phenyl-1-acetone in Example 8 was replaced with Darocur 2959, and the same curing operation was performed. The surface was slightly viscous in 25s and completely cured in 48s.

Comparing the curing results of the above Examples 4 and 8 and Comparative Examples 1 and 2, it can be found that the compound provided by the present invention is used as a photo-curing initiator, and the curing effect initiated by it is comparable to the photo-curing initiated by mature initiators on the market The effects are completely equivalent, and the compound of the present invention has the characteristics of water solubility, high polymerizability, and extremely low odor, so it is a new type of photocuring initiator with great market prospects.

Industrial applicability

The ketone photoinitiator compound provided by the present invention has a special active side chain, has the characteristics of water-solubility, can be polymerized with extremely low odor, and has a good curing effect. As an environmentally friendly product, it is expected to be applied In photo-initiated free-radical polymerization of carbon-carbon double bond compounds such as acrylates.

Claims

Rights request

1. A photoinitiator compound having the structure shown in Formula I:

among them,

!! ^ And R ₂ are each independently selected from H or CH _3;

Z is CR ₃ R ₄ (0R ₅ ) or phenyl;

Is 11, d- ₃ alkyl or phenyl,

R ₄ is H, d- ₃ fluorenyl, or ₃ alkoxy,

Or R ₃ R ₄ is one (C¾) ₅ —;

R ₅ is! !! Or ^ alkyl;

X is 0 or S;

E l or 2.

2. The compound according to claim 1, wherein in the compound, X is 0; Z is CR ₃ R ₄ (0R ₅ ), R ₃ is d- ₃ alkyl; and d-3 alkane Base; or one (C) ₅ —; '

3. The compound according to claim 1, wherein in the compound, X is 0; Z is phenyl.

4. The compound according to claim 1, wherein the compound is selected from one of the following specific compounds:

2-hydroxy-2-methyl-4, _ (2-hydroxypropoxy) phenyl-1-acetone;

12

Correction page (Article 91) ISA / CN 1-hydroxycyclohexyl-4,-(2-hydroxypropoxy) benzophenone;

2-hydroxy-2-methyl-4,-[2- (2-hydroxypropoxy) propoxy] phenyl-1 -acetone; 2-hydroxy-2-methyl-4,-(2-hydroxy 1-methylethoxy) phenyl-1-acetone;

1-hydroxycyclohexyl-4,-(2-hydroxy-1-methylethoxy) benzophenone;

2 -hydroxy-2-methyl-4,-[2- (2-hydroxy-1-methylethoxy)-1-methylethoxy] phenyl-1 -acetone;

-(2-hydroxypropoxy) benzophenone.

5. A method for preparing a compound according to claim 2, characterized in that, the method comprises the following steps in sequence: using propylene glycol phenyl ether as a raw material, undergoing esterification, acylation reaction, halogenation reaction, alkali hydrolysis reaction, The target compound is prepared.

The method according to claim 5, further comprising the step of purifying by distillation under reduced pressure and / or crystallization.

7. A method for preparing a compound according to claim 3, characterized in that the method comprises the following steps in sequence: using propylene glycol phenyl ether as a raw material, and subjecting it to esterification, acylation, and alkaline hydrolysis to obtain the target compound .

The method according to claim 7, further comprising the step of purifying by distillation under reduced pressure and / or crystallization.

9. A photocurable system comprising at least one methacrylic acid and / or acrylate compound, a prepolymer and / or a reactive diluent, and a photoinitiator, wherein the photoinitiator comprises at least A compound according to claim 1.

10. The photocurable system according to claim 9, wherein the prepolymer and / or the reactive diluent contain a C = C double bond group.

The photocurable system according to claim 9 or 10, wherein the prepolymer and / or reactive diluent is an acryl prepolymer and / or reactive diluent.

01〜10%。 12. The photocurable system according to claim 9, characterized in that the added amount of the photoinitiator is 0.01 to 10% of the total weight of the system.

13. A photo-curable aqueous system comprising at least one water-soluble or water-emulsified methacrylic acid and / or acrylated polymer, an auxiliary agent and a photoinitiator, wherein the photoinitiator comprises At least one compound of claim 1.

01〜; L0%。 14. The photocurable aqueous system according to claim 13, characterized in that the addition amount of the photoinitiator is 0.01 to 1 by weight of the polymer.

15. The photocurable aqueous system according to claim 13, wherein the content of the polymer is 10 to 85 Wt% of the entire system.

16. The compound according to any one of claims 1 to 4 used as a photoinitiator for curing a carbon-carbon double bond compound.

17. The application according to claim 16, wherein the carbon-carbon double bond