CN116285792A - Polyacrylate UV (ultraviolet) photo-curing hot-melt pressure-sensitive adhesive and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of adhesives, and particularly discloses a polyacrylate UV (ultraviolet) photo-curing hot-melt pressure-sensitive adhesive and a preparation method thereof, wherein the pressure-sensitive adhesive comprises the following components: soft monomers, hard monomers, functional monomers, crosslinking monomers, initiators and photosensitizers; the preparation method comprises the following steps: preparing a mixed monomer solution, preparing an initiator solution, preparing a prepolymer, dripping the initiator for the second time, adding a photosensitizer, filtering, and cooling to obtain the polyacrylate UV photo-curing hot-melt pressure-sensitive adhesive. The invention adopts the method that the polyacrylate prepolymer is prepared by mixing soft monomer, hard monomer functional monomer and crosslinking monomer and initiator for a plurality of times, thereby saving the cost and randomly adjusting the pressure-sensitive adhesive performance; by adopting bulk polymerization, the polyacrylate pressure-sensitive adhesive has excellent stripping force, initial adhesion, persistent adhesion, water resistance, weather resistance and high and low temperature resistance.

Description

Polyacrylate UV (ultraviolet) photo-curing hot-melt pressure-sensitive adhesive and preparation method thereof

Technical Field

The invention relates to the technical field of adhesives, in particular to a polyacrylate UV (ultraviolet) photo-curing hot-melt pressure-sensitive adhesive and a preparation method thereof.

Background

The pressure sensitive adhesive is an adhesive which can be used for bonding an adherend by applying pressure, and is also an adhesive commonly used in daily life. At present, polyacrylate pressure-sensitive adhesives are mainly divided into solvent pressure-sensitive adhesives and water-based pressure-sensitive adhesives, and the application range of the polyacrylate pressure-sensitive adhesives covers the fields of civil use, national defense, aerospace and the like.

The solvent type polyacrylate pressure-sensitive adhesive has the advantages of high stripping, high initial adhesion, high holding adhesion, water white resistance, strong weather resistance and the like, but uses an organic solvent as a solvent, and a large amount of volatile organic solvent can be generated during coating so as to pollute the environment, thus the application of the solvent type polyacrylate pressure-sensitive adhesive is limited to a certain extent; the water-based acrylic ester pressure-sensitive adhesive takes water as a solvent, is environment-friendly, but has poorer performance than the solvent-based acrylic ester pressure-sensitive adhesive, and has a certain limit on the application range; the UV photo-curing hot-melt pressure-sensitive adhesive well solves the defects of the two, has excellent performance of a solvent-type pressure-sensitive adhesive, adopts bulk polymerization, does not generate an organic solvent which can be generated, cures by UV illumination, is environment-friendly, and reduces energy consumption. Along with the importance of environmental protection, safety and energy conservation and the continuous expansion of pressure-sensitive adhesive application, the development of the pressure-sensitive adhesive towards low pollution, high performance and functionalization is promoted, and the UV photo-curing hot-melt pressure-sensitive adhesive also becomes a development direction of polyacrylate pressure-sensitive adhesive.

Disclosure of Invention

The invention aims to solve the problems in the background art and provides a polyacrylate UV light curing hot-melt pressure-sensitive adhesive and a preparation method thereof, so as to solve the problems.

In order to achieve the aim, the invention provides a polyacrylate UV photo-curing hot-melt pressure-sensitive adhesive, which comprises the following components in percentage by mass:

preferably, the soft monomer is one or more of butyl acrylate, isooctyl acrylate, octadecyl acrylate, tetradecyl acrylate, heptadecyl acrylate, hexadecyl acrylate, ethyl acrylate and isobutyl acrylate;

preferably, the hard monomer is one or more of methyl acrylate, methyl methacrylate, cyclohexyl methacrylate, isobornyl acrylate, styrene and vinyl acetate;

preferably, the functional monomer is one or more of acrylic acid, methacrylic acid, itaconic acid and beta-acryloxypropionic acid;

preferably, the crosslinking monomer is one or more of glycidyl methacrylate, divinylbenzene, acrylamide, N-methylene bisacrylamide, triallyl cyanurate, pentaerythritol triallyl ether, glycidyl methacrylate, trimethylolpropane triacrylate, N-methylolacrylamide and N-methoxy methacrylamide;

preferably, the initiator is one or more of azodiisobutyronitrile (AI BN), benzoyl Peroxide (BPO) and Azodiisoheptonitrile (AIVN);

preferably, the photosensitizer is one or more of 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide (TPO), 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), benzoin dimethyl ether (BDK) and 4-Chlorobenzophenone (CBP).

The invention also discloses a preparation method of the polyacrylate UV photo-curing hot-melt pressure-sensitive adhesive, which is used for preparing the pressure-sensitive adhesive and comprises the following steps:

s1, preparing a mixed monomer solution: stirring all the soft monomer, the hard monomer, the crosslinking monomer and the functional monomer for 15-45 minutes at the stirring speed of 300-800 revolutions per minute to fully mix the soft monomer, the hard monomer, the crosslinking monomer and the functional monomer to obtain a mixed monomer solution;

s2, preparing an initiator solution: taking out 10-20% of mixed monomers from the S1 for standby, adding an initiator into the mixed monomers, and stirring the mixed monomers to dissolve the initiator to obtain an initiator solution;

s3, preparation of prepolymer: adding the rest mixed monomer in the S1 into a reaction bottle, slowly heating to 130-150 ℃, adding 5-10% of initiator solution in the S2, reacting for 10-30 minutes, and obviously increasing the viscosity of the solution at the bottom of the kettle to obtain seed solution;

s4, respectively dripping the rest initiator solution into the seed solution in the S3 at 130-150 ℃ for 0.5-1 hour, after dripping, preserving heat for 3-4 hours at 130-150 ℃, after preserving heat, adding 0.1-0.6% of photosensitizer into the mixture, stirring the mixture for 30-45 minutes, filtering and discharging the mixture at 130-150 ℃, and cooling the mixture to obtain the polyacrylate UV light-cured hot melt pressure-sensitive adhesive.

Further, the mass percentage of the raw materials is 60-85% of the soft monomer; 5-25% of hard monomer; 2-15% of functional monomer; 0.5-6% of cross-linking monomer; initiator 0.1-0.6%; 0.1-0.6% of photosensitizer.

Specifically, the soft monomer in S1 is one or more of butyl acrylate, isooctyl acrylate, octadecyl acrylate, tetradecyl acrylate, heptadecyl acrylate, hexadecyl acrylate, ethyl acrylate and isobutyl acrylate;

the hard monomer is one or more of methyl acrylate, methyl methacrylate, cyclohexyl methacrylate, isobornyl acrylate, styrene and vinyl acetate;

the functional monomer is one or more of acrylic acid, methacrylic acid, itaconic acid and beta-acryloyloxy propionic acid;

the crosslinking monomer is one or more of glycidyl methacrylate, divinylbenzene, acrylamide, N-methylene bisacrylamide, triallyl cyanurate, pentaerythritol triallyl ether, glycidyl methacrylate, trimethylolpropane triacrylate, N-methylolacrylamide and N-methoxy methacrylamide;

the initiator in S2 is one or more of Azodiisobutyronitrile (AIBN), benzoyl Peroxide (BPO) and Azodiisoheptonitrile (AIVN);

the photosensitizer in S4 is one or more of 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide (TPO), 2-hydroxy-2-methyl-1-phenyl-1-acetone (1173), benzoin dimethyl ether (BDK) and 4-Chlorobenzophenone (CBP).

The beneficial effects of the invention are as follows:

(1) The polyacrylate prepolymer is prepared by mixing the soft monomer, the hard monomer functional monomer and the crosslinking monomer and the initiator for multiple times according to a specific proportion, so that the cost is saved, and the performance of the pressure-sensitive adhesive can be adjusted at will;

(2) The high-temperature polymerization reaction is adopted, the mixed monomer is subjected to the high-temperature polymerization reaction at the high temperature of 130-150 ℃, and the polymerization of the monomer is increased, so that the viscosity and other performances of the pressure-sensitive adhesive are increased, and the prepared polyacrylate pressure-sensitive adhesive has excellent stripping force, initial adhesion, lasting adhesion, water resistance, weather resistance and high-low temperature resistance;

(3) The pressure-sensitive adhesive does not add a solvent, so that the pressure-sensitive adhesive is prevented from generating a large amount of volatile organic solvents in the coating process, and the environmental pollution is reduced; and the operation is simple and convenient during coating, UV light curing can be adopted, the coating speed is high, and the production efficiency is improved.

Detailed Description

The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Example 1

(1) Preparing a mixed monomer solution: 200 parts of butyl acrylate, 37.5 parts of methyl methacrylate, 7.5 parts of methacrylic acid and 5 parts of diethylbenzene are weighed as mixed monomers and put into a stirring bottle, and the stirring speed is 300 revolutions per minute, and the mixed monomers are stirred for 30 minutes, so that the mixed monomers are fully mixed to obtain a mixed monomer solution;

(2) Preparing an initiator solution: taking out 15% of the mixed monomer from the step (1) for standby, weighing 0.5 part of AI BN, adding the AI BN, and stirring to dissolve the AI BN to obtain an initiator solution;

(3) Preparation of prepolymer: adding the residual mixed monomer in the step (1) into a reaction bottle, slowly heating to 140 ℃, adding 5% of the initiator solution in the step (2), and reacting for 30 minutes, wherein the viscosity of the solution at the bottom of the kettle is obviously increased, thus obtaining a seed solution;

(4) And (3) respectively dripping the rest initiator solution into the seed solution in the step (3) at 140 ℃ for 1 hour, after dripping, preserving heat for 3 hours at 140 ℃, after preserving heat, weighing 1.5 parts of TPO, adding into the mixture, stirring for 30 minutes, filtering and discharging at 140 ℃, and cooling to obtain the polyacrylate UV photo-curing hot melt pressure-sensitive adhesive.

Example 2

(1) Preparing a mixed monomer solution: 100 parts of butyl acrylate, 62.5 parts of isooctyl acrylate, 50 parts of methyl acrylate, 25 parts of glycidyl methacrylate and 5 parts of diethylbenzene are weighed as mixed monomers, put into a stirring bottle, and stirred for 40 minutes at a stirring speed of 400 rpm, so that the mixed monomers are fully mixed to obtain a mixed monomer solution;

(2) Preparing an initiator solution: taking out 10% of mixed monomers from the step (1) for standby, weighing 0.75 part of BPO, adding the BPO into the mixed monomers, and stirring the mixture to dissolve the BPO to obtain an initiator solution;

(3) Preparation of prepolymer: adding the residual mixed monomer in the step (1) into a reaction bottle, slowly heating to 130 ℃, adding 5% of the initiator solution in the step (2), and reacting for 30 minutes, wherein the viscosity of the solution at the bottom of the kettle is obviously increased, thus obtaining a seed solution;

(4) And (3) respectively dripping the rest initiator solution into the seed solution in the step (3) at 130 ℃ for 1 hour, after dripping, preserving heat for 4 hours at 130 ℃, after preserving heat, weighing 1 part of BDK, adding the BDK, stirring for 30 minutes, filtering and discharging at 130 ℃, and cooling to obtain the polyacrylate UV light-cured hot-melt pressure-sensitive adhesive.

Example 3

(1) Preparing a mixed monomer solution: weighing 75 parts of butyl acrylate, 137.5 parts of heptadecyl acrylate, 12.5 parts of isobornyl methacrylate, 15 parts of acrylic acid and 10 parts of acrylamide as mixed monomers, putting the mixed monomers into a stirring bottle, stirring at a stirring speed of 600 revolutions per minute for 40 minutes, and fully mixing the mixed monomers to obtain a mixed monomer solution;

(2) Preparing an initiator solution: taking out 10% of the mixed monomer from the step (1) for standby, weighing 1.5 parts of AIVN, adding the AIVN into the mixed monomer, and stirring the AIVN to dissolve the AIVN to obtain an initiator solution;

(3) Preparation of prepolymer: adding the residual mixed monomer in the step (1) into a reaction bottle, slowly heating to 150 ℃, adding 7% of the initiator solution in the step (2), and reacting for 20 minutes, wherein the viscosity of the solution at the bottom of the kettle is obviously increased, thus obtaining a seed solution;

(4) And (3) respectively dripping the rest initiator solution into the seed solution in the step (3) at 150 ℃ for 0.5 hour, after dripping, preserving heat for 3.5 hours at 150 ℃, and after preserving heat, weighing 1 part of BDK, adding the BDK into the mixture, stirring for 30 minutes, filtering and discharging at 150 ℃, and cooling to obtain the polyacrylate UV light-cured hot-melt pressure-sensitive adhesive.

Example 4

(1) Preparing a mixed monomer solution: 62.5 parts of benzyl methacrylate, 150 parts of isodecyl acrylate, 22.5 parts of beta-acryloyloxy propionic acid and 15 parts of glycidyl methacrylate are weighed as mixed monomers, put into a stirring bottle, and stirred for 15 minutes at a stirring speed of 400 rpm, so that the mixed monomers are fully mixed to obtain a mixed monomer solution;

(2) Preparing an initiator solution: taking out 15% of the mixed monomer from the step (1) for standby, weighing 0.75 part of AI BN, adding the AI BN, and stirring to dissolve the AI BN to obtain an initiator solution;

(3) Preparation of prepolymer: adding the residual mixed monomer in the step (1) into a reaction bottle, slowly heating to 140 ℃, adding 10% of the initiator solution in the step (2), and reacting for 25 minutes, wherein the viscosity of the solution at the bottom of the kettle is obviously increased, thus obtaining a seed solution;

(4) And (3) respectively dripping the rest initiator solution into the seed solution in the step (3) at 140 ℃ for 1 hour, after dripping, preserving heat for 3 hours at 140 ℃, after preserving heat, weighing 0.75 part of TPO, adding into the mixture, stirring for 30 minutes, filtering and discharging at 140 ℃, and cooling to obtain the polyacrylate UV light-cured hot-melt pressure-sensitive adhesive.

Example 5

(1) Preparing a mixed monomer solution: weighing 25 parts of isobornyl methacrylate, 187.5 parts of isooctyl acrylate, 30 parts of beta-acryloxypropionic acid and 7.5 parts of trimethylolpropane triacrylate as mixed monomers, putting the mixed monomers into a stirring bottle, stirring at a stirring speed of 500 revolutions per minute for 30 minutes, and fully mixing the mixed monomers to obtain a mixed monomer solution;

(2) Preparing an initiator solution: taking out 10% of mixed monomers from the step (1) for standby, weighing 0.875 part of BPO, adding the BPO into the mixed monomers, and stirring the mixture to dissolve the BPO to obtain an initiator solution;

(3) Preparation of prepolymer: adding the residual mixed monomer in the step (1) into a reaction bottle, slowly heating to 140 ℃, adding 5% of the initiator solution in the step (2), and reacting for 25 minutes, wherein the viscosity of the solution at the bottom of the kettle is obviously increased, thus obtaining a seed solution;

(4) And (3) respectively dripping the rest initiator solution into the seed solution in the step (3) at 140 ℃ for 1 hour, after dripping, preserving heat for 3 hours at 140 ℃, weighing 0.375 part of CBP, adding the CBP, stirring for 30 minutes, filtering and discharging at 140 ℃, and cooling to obtain the polyacrylate UV photo-curing hot-melt pressure-sensitive adhesive.

Example 6

(1) Preparing a mixed monomer solution: 15 parts of cyclohexyl methacrylate, 200 parts of octadecyl acrylate, 25 parts of acrylic acid and 10 parts of N-methoxy methacrylamide are weighed as mixed monomers, put into a stirring bottle, and stirred for 30 minutes at a stirring speed of 500 revolutions per minute, so that the mixed monomers are fully mixed to obtain a mixed monomer solution;

(2) Preparing an initiator solution: taking out 15% of mixed monomers from the step (1) for standby, weighing 1.125 parts of AIBN, adding the AIBN, and stirring to dissolve the AIBN to obtain an initiator solution;

(3) Preparation of prepolymer: adding the residual mixed monomer in the step (1) into a reaction bottle, slowly heating to 145 ℃, adding 5% of the initiator solution in the step (2), and reacting for 30 minutes, wherein the viscosity of the solution at the bottom of the kettle is obviously increased, thus obtaining a seed solution;

(4) Respectively dripping the rest initiator solution into the seed solution in the step (3) at 145 ℃ for 1 hour, preserving heat for 3 hours at 145 ℃ after dripping, weighing 1.25 parts of 1173, adding into the mixture, stirring for 25 minutes, filtering and discharging at 145 ℃, and cooling to obtain the polyacrylate UV photo-curing hot-melt pressure-sensitive adhesive;

example 7

(1) Preparing a mixed monomer solution: weighing 25 parts of styrene, 175 parts of tetradecyl acrylate, 35 parts of methacrylic acid and 15 parts of acrylamide as mixed monomers, putting the mixed monomers into a stirring bottle, stirring at a stirring speed of 500 revolutions per minute for 35 minutes, and fully mixing the mixed monomers to obtain a mixed monomer solution;

(2) Preparing an initiator solution: taking out 10% of the mixed monomer from the step (1) for standby, weighing 1 part of AIVN, adding the AIVN into the mixed monomer, and stirring the AIVN to dissolve the AIVN to obtain an initiator solution;

(3) Preparation of prepolymer: adding the residual mixed monomer in the step (1) into a reaction bottle, slowly heating to 150 ℃, adding 5% of the initiator solution in the step (2), and reacting for 20 minutes, wherein the viscosity of the solution at the bottom of the kettle is obviously increased, thus obtaining a seed solution;

(4) And (3) respectively dripping the rest initiator solution into the seed solution in the step (3) at 150 ℃ for 0.5 hour, after dripping, preserving heat for 3 hours at 150 ℃, after preserving heat, weighing 0.25 part of TPO, adding into the mixture, stirring for 30 minutes, filtering and discharging at 150 ℃, and cooling to obtain the polyacrylate UV light-cured hot-melt pressure-sensitive adhesive.

Viscosity of the glue solution: heating the glue solution to 150 ℃ and testing the viscosity of the glue solution;

peel force: dissolving the hot melt adhesive with ethyl acetate to adjust the solid content to 50%, coating the hot melt adhesive on 50 mu m PET, and testing the hot melt adhesive with the adhesive thickness of 25 mu m by using a tensile machine;

annular primary adhesion: dissolving the hot melt adhesive with ethyl acetate to adjust the solid content to 50%, coating the hot melt adhesive on 50 mu m PET, and testing the hot melt adhesive with the adhesive thickness of 25 mu m by using a tensile machine;

and (3) sticking: dissolving the hot melt adhesive with ethyl acetate to adjust the solid content to 50%, coating the hot melt adhesive on 50 mu m PET, coating the hot melt adhesive with the adhesive thickness of 25 mu m, and hanging a weight of 1Kg at normal temperature for testing;

test results

From the test results, compared with the samples, the polyacrylate UV light curing hot melt pressure-sensitive adhesive prepared by the embodiment of the invention has lower viscosity, higher stripping force, annular initial adhesion and longer holding adhesion.

The present invention is described in detail by the above examples, but the present invention is not limited to the above detailed methods, i.e., it does not mean that the present invention must be practiced depending on the above detailed methods. The description of this section is intended to be exemplary and explanatory only and should not be construed as limiting the scope of the invention.

Claims (10)

1. The polyacrylate UV photo-curing hot-melt pressure-sensitive adhesive is characterized by comprising the following components in percentage by mass:

2. the polyacrylate UV light-curable hot-melt pressure-sensitive adhesive according to claim 1, wherein the soft monomer is one or more of butyl acrylate, isooctyl acrylate, octadecyl acrylate, tetradecyl acrylate, heptadecyl acrylate, hexadecyl acrylate, ethyl acrylate and isobutyl acrylate.

3. The polyacrylate UV light-curable hot-melt pressure-sensitive adhesive according to claim 1, wherein the hard monomer is one or more of methyl acrylate, methyl methacrylate, cyclohexyl methacrylate, isobornyl acrylate, styrene and vinyl acetate.

4. The polyacrylate UV light curing hot melt pressure sensitive adhesive according to claim 1, wherein the functional monomer is one or more of acrylic acid, methacrylic acid, itaconic acid and beta-acryloxypropionic acid.

5. The polyacrylate UV light curing hot melt pressure-sensitive adhesive according to claim 1, wherein the crosslinking monomer is one or more of glycidyl methacrylate, divinylbenzene, acrylamide, N-methylenebisacrylamide, triallyl cyanurate, pentaerythritol triallyl ether, glycidyl methacrylate, trimethylolpropane triacrylate, N-methylolacrylamide and N-methoxymethacrylamide.

6. The polyacrylate UV photo-curing hot melt pressure sensitive adhesive of claim 1, wherein the initiator is one or more of Azobisisobutyronitrile (AIBN), benzoyl Peroxide (BPO) and Azobisisoheptonitrile (AIVN).

7. The polyacrylate UV curable hot melt pressure sensitive adhesive according to claim 1, wherein the photosensitizer is one or more of 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide (TPO), 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), benzoin dimethyl ether (BDK), 4-Chlorobenzophenone (CBP).

8. A method for preparing polyacrylate UV light curing hot melt pressure sensitive adhesive for preparing the pressure sensitive adhesive as claimed in any one of claims 1 to 7, characterized by the steps of:

s1, preparing a mixed monomer solution: stirring all the soft monomer, the hard monomer, the crosslinking monomer and the functional monomer for 15-45 minutes at the stirring speed of 300-800 revolutions per minute to fully mix the soft monomer, the hard monomer, the crosslinking monomer and the functional monomer to obtain a mixed monomer solution;

s2, preparing an initiator solution: taking out 10-20% of mixed monomers from the S1 for standby, adding an initiator into the mixed monomers, and stirring the mixed monomers to dissolve the initiator to obtain an initiator solution;

s3, preparation of prepolymer: adding the rest mixed monomer in the S1 into a reaction bottle, slowly heating to 130-150 ℃, adding 5-10% of initiator solution in the S2, reacting for 10-30 minutes, and obviously increasing the viscosity of the solution at the bottom of the kettle to obtain seed solution;

s4, respectively dripping the rest initiator solution into the seed solution in the S3 at 130-150 ℃ for 0.5-1 hour, after dripping, preserving heat for 3-4 hours at 130-150 ℃, after preserving heat, adding 0.1-0.6% of photosensitizer into the mixture, stirring the mixture for 30-45 minutes, filtering and discharging the mixture at 130-150 ℃, and cooling the mixture to obtain the polyacrylate UV light-cured hot melt pressure-sensitive adhesive.

9. The method for preparing the polyacrylate UV light-cured hot-melt pressure-sensitive adhesive according to claim 8, wherein the mass percentage of the raw materials is 60-85% of the soft monomer; 5-25% of hard monomer; 2-15% of functional monomer; 0.5-6% of cross-linking monomer; initiator 0.1-0.6%; 0.1-0.6% of photosensitizer.

10. The method for preparing the polyacrylate UV light-cured hot-melt pressure-sensitive adhesive according to claim 8, wherein the soft monomer in S1 is one or more of butyl acrylate, isooctyl acrylate, octadecyl acrylate, tetradecyl acrylate, heptadecyl acrylate, hexadecyl acrylate, ethyl acrylate and isobutyl acrylate;

the hard monomer is one or more of methyl acrylate, methyl methacrylate, cyclohexyl methacrylate, isobornyl acrylate, styrene and vinyl acetate;

the functional monomer is one or more of acrylic acid, methacrylic acid, itaconic acid and beta-acryloyloxy propionic acid;

the crosslinking monomer is one or more of glycidyl methacrylate, divinylbenzene, acrylamide, N-methylene bisacrylamide, triallyl cyanurate, pentaerythritol triallyl ether, glycidyl methacrylate, trimethylolpropane triacrylate, N-methylolacrylamide and N-methoxy methacrylamide;

the initiator in S2 is one or more of Azodiisobutyronitrile (AIBN), benzoyl Peroxide (BPO) and Azodiisoheptonitrile (AIVN);

the photosensitizer in S4 is one or more of 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide (TPO), 2-hydroxy-2-methyl-1-phenyl-1-acetone (1173), benzoin dimethyl ether (BDK) and 4-Chlorobenzophenone (CBP).