阅读说明：本技术 一种基于二苯甲酮的可聚合型光引发剂及其制备方法 (Polymerizable photoinitiator based on benzophenone and preparation method thereof ) 是由 胡来月 钟晓峰 王婷 代俊 陶钱铸 杨梅 于 2019-10-24 设计创作，主要内容包括：本发明公开一种基于二苯甲酮的可聚合型光引发剂,涉及光固化合成技术领域,基于现有的光引发剂存在导致材料变黄的问题而提出的。该引发剂结构通式如下：<Image he="216" wi="540" file="DDA0002245582630000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>n＝1～6；本发明还提供有上述光引发剂的制备方法。本发明的有益效果在于：本发明在分子结构中引入了含不饱和键的烷基链,使其可以与乙烯类单体共聚,从而避免迁移而导致材料黄变。(The invention discloses a polymerizable photoinitiator based on benzophenone, relates to the technical field of photocuring synthesis, and is provided based on the problem that the existing photoinitiator causes yellowing of materials. The structural general formula of the initiator is as follows: n is 1-6; the invention also provides a preparation method of the photoinitiator. The invention has the beneficial effects that: according to the invention, an alkyl chain containing an unsaturated bond is introduced into a molecular structure, so that the alkyl chain can be copolymerized with ethylene monomers, and yellowing of the material caused by migration is avoided.)

1. A polymerizable photoinitiator based on benzophenone is characterized in that the chemical structure general formula is as follows:

the polymerizable photoinitiator is mainly prepared from the following raw materials in parts by weight: 1 part of 4-chlorobenzophenone, 1-5 parts of polyethylene glycol, 1-3 parts of inorganic base, 4-20 parts of dichloromethane and 2-10 parts of water.

2. A polymerizable benzophenone-based photoinitiator according to claim 1 wherein: the polyethylene glycol comprises PEG100, PEG200 or PEG 300.

3. A polymerizable benzophenone-based photoinitiator according to claim 1 wherein: the inorganic base comprises sodium carbonate, sodium bicarbonate, potassium carbonate or potassium bicarbonate.

4. A process for preparing a benzophenone-based polymerizable photoinitiator according to claim 1 comprising the steps of:

(1) mixing polyethylene glycol, 4-chlorobenzophenone and potassium carbonate according to the weight parts, heating to 120-125 ℃ after stirring, reacting for 5-6 hours, cooling to room temperature, sequentially adding 2-10 parts of dichloromethane and the water according to the weight parts, stirring, standing for layering to obtain a water phase and an organic phase, extracting the water phase with 2-10 parts of dichloromethane, combining an extracted product with the organic phase, drying by a drying agent, and distilling under reduced pressure to obtain an intermediate product;

(2) adding the intermediate product obtained in the step (1) and acrylic acid into toluene, adding a catalyst, heating to 110 ℃, reacting for 4-6 h, cooling to room temperature after reaction, adding water, stirring, drying an organic phase obtained after layering by a drying agent, and concentrating under reduced pressure to obtain the benzophenone-based polymerizable photoinitiator.

5. The method of claim 4, wherein the polymerizable benzophenone-based photoinitiator comprises: in the step (1), the mass ratio of the polyethylene glycol to the 4-chlorobenzophenone to the inorganic base is 4:1: 2.

6. The method of claim 4, wherein the polymerizable benzophenone-based photoinitiator comprises: the volume ratio of the dichloromethane to the water in the step (1) is 1: 1.

7. The method of claim 4, wherein the polymerizable benzophenone-based photoinitiator comprises: the drying agent in the step (1) and the step (2) is anhydrous sodium sulfate.

8. The method of claim 4, wherein the polymerizable benzophenone-based photoinitiator comprises: the mass ratio of the intermediate product to the acrylic acid in the step (2) is 2: 1.

9. The method of claim 4, wherein the polymerizable benzophenone-based photoinitiator comprises: the catalyst in the step (2) is concentrated sulfuric acid.

10. The method of claim 4, wherein the polymerizable benzophenone-based photoinitiator comprises: the temperature of the water bath for decompression concentration in the step (2) is 30-60 ℃.

Technical Field

The invention relates to the technical field of photocuring synthesis, in particular to a benzophenone-based polymerizable photoinitiator and a preparation method thereof.

Background

Photocuring has been widely used in many important technical fields, particularly because of its own advantages, low VOC emission, is a green technology, and is mainly used in the fields of fast curing coatings, printing inks, adhesives, and the like. Photoinitiators play an important role in UV curing systems, and they can absorb energy of a specific wavelength to generate reactive species to initiate polymerization of the entire system.

Benzophenone (BP) is a common hydrogen abstraction photoinitiator, has low price, simple synthesis and easy storage, and is widely applied to ultraviolet curing coatings. The photoinitiator is mainly used for an acrylate monomer photopolymerization system and is one of the most widely used initiators at present. The thermal stability of the benzophenone is superior to that of a cracking type photoinitiator, and the benzophenone has a certain antioxidant polymerization inhibition effect when being matched with an active amine system for use, so that the benzophenone is more widely applied. In addition, BP has better solubility in common monomer resin. However, BP is inferior to cleavage type photoinitiators such as Darocur1173 and Irgacure184 in photoinitiation activity, and is low in melting point, sublimable and easy to lose due to volatilization at the time of temperature rise; moreover, BP has small molecular weight and is easy to migrate and separate out from a polymer network, which restricts the application of the BP in the aspects of contacting with human skin, such as food, drug packaging and the like, so that the research on the modification and the derivative of BP is one of the hot spots of the traditional photoinitiator. With the development of the industry, people put higher requirements on the initiation performance of the benzophenone photoinitiator.

A preparation method of a polymerizable benzophenone derivative photoinitiator is disclosed in the patent CN102863323A, and benzophenone containing epoxy group is used as a raw material to generate a ring-opening reaction with unsaturated carboxylic acid or unsaturated carboxylic ester in the presence of a polymerization inhibitor and tetrabutylammonium bromide to generate the polymerizable photoinitiator. A conventional photoinitiator is apt to undergo sublimation migration when used alone, resulting in yellowing of the material, and JP2001348412A discloses a liquid curable resin composition containing 2-methyl-1- [4- (methylthio) phenyl ] -2- (4-morpholinyl) -1-propanone as a photoinitiator component. The above methods have some problems, and the polymerizable photoinitiators prepared in the above patents have a problem of causing yellowing of materials.

Disclosure of Invention

One of the technical problems to be solved by the present invention is to provide a benzophenone-based polymerizable photoinitiator capable of avoiding yellowing of the material due to migration.

The invention adopts the following technical scheme to solve the technical problems:

the invention provides a benzophenone-based polymerizable photoinitiator which is characterized by comprising the following chemical structural general formula:

the polymerizable photoinitiator is mainly prepared from the following raw materials in parts by weight: 1 part of 4-chlorobenzophenone, 1-5 parts of polyethylene glycol, 1-3 parts of inorganic base, 4-20 parts of dichloromethane and 2-10 parts of water.

The invention provides a benzophenone derivative photoinitiator, wherein an alkyl chain containing an unsaturated bond is introduced into a molecular structure, so that the benzophenone derivative photoinitiator can be copolymerized with an ethylene monomer, and yellowing of materials caused by migration is avoided.

Preferably, the polyethylene glycol comprises PEG100, PEG200 or PEG 300.

Preferably, the inorganic base comprises sodium carbonate, sodium bicarbonate, potassium carbonate or potassium bicarbonate.

The inorganic base acts as an acid-binding agent for the reaction.

The second technical problem to be solved by the present invention is to provide a preparation method of a benzophenone-based polymerizable photoinitiator capable of avoiding material yellowing caused by migration.

The invention adopts the following technical scheme to solve the technical problems:

the invention provides a preparation method of a benzophenone-based polymerizable photoinitiator, which comprises the following steps:

(1) mixing polyethylene glycol, 4-chlorobenzophenone and potassium carbonate according to the weight parts, heating to 120-125 ℃ after stirring, reacting for 5-6 hours, cooling to room temperature, sequentially adding 2-10 parts of dichloromethane and the water according to the weight parts, stirring, standing for layering to obtain a water phase and an organic phase, extracting the water phase with 2-10 parts of dichloromethane, combining an extracted product with the organic phase, drying by a drying agent, and distilling under reduced pressure to obtain an intermediate product;

(2) adding the intermediate product obtained in the step (1) and acrylic acid into toluene, adding a catalyst, heating to 110 ℃, reacting for 4-6 h, cooling to room temperature after reaction, adding water, stirring, drying an organic phase obtained after layering by a drying agent, and concentrating under reduced pressure to obtain the benzophenone-based polymerizable photoinitiator.

The invention introduces polyethylene glycol into the molecular structure, improves the compatibility of the initiator and the copolymer, and ensures that the cross-linked product has more excellent mechanical property and heat resistance.

Further, the mass ratio of the polyethylene glycol, the 4-chlorobenzophenone and the inorganic base in the step (1) is 4:1: 2.

Further, the volume ratio of the dichloromethane to the water in the step (1) is 1: 1.

Further, the drying agent in the step (1) and the step (2) is anhydrous sodium sulfate.

Further, the mass ratio of the intermediate product to acrylic acid in the step (2) is 2: 1.

Further, the catalyst in the step (2) is concentrated sulfuric acid.

Further, the temperature of the water bath concentrated under reduced pressure in the step (2) is 30-60 ℃.

The invention provides a preparation method of the benzophenone derivative photoinitiator, which has simple reaction process, adopts common industrial raw materials, only needs two steps to obtain the polymerizable photoinitiator with each molecule containing a benzophenone unit, has mild reaction conditions, and is simple in post-treatment and easy for industrial production.

The invention has the beneficial effects that:

(1) the invention provides a benzophenone derivative photoinitiator, wherein an alkyl chain containing an unsaturated bond is introduced into a molecular structure, so that the benzophenone derivative photoinitiator can be copolymerized with an ethylene monomer, and yellowing of materials caused by migration is avoided.

(2) The invention introduces polyethylene glycol into the molecular structure, improves the compatibility of the initiator and the copolymer, and ensures that the cross-linked product has more excellent mechanical property and heat resistance.

(3) The invention provides a preparation method of the benzophenone derivative photoinitiator, which has simple reaction process, adopts common industrial raw materials, only needs two steps to obtain the polymerizable photoinitiator with each molecule containing a benzophenone unit, has mild reaction conditions, and is simple in post-treatment and easy for industrial production.

Detailed Description

The present invention will be described in further detail with reference to examples.

Test materials, reagents and the like used in the following examples are commercially available unless otherwise specified.