CN114560993A - A kind of preparation method of chalcone-terminated photosensitive water-based polyurethane/epoxy acrylate - Google Patents

Abstract

The invention provides chalcone-terminated photosensitive waterborne polyurethane and a preparation method thereof, and a waterborne polyurethane/epoxy acrylate curing film prepared from the chalcone-terminated photosensitive waterborne polyurethane, wherein the photosensitive waterborne polyurethane is prepared from raw materials comprising polyisocyanate, oligomer polyol and chalcone, the polyurethane is subjected to end-capping treatment by the chalcone, a photosensitive group is added into the polyurethane through a covalent bond, so that the polyurethane is endowed with excellent photocuring performance, the photosensitive waterborne polyurethane/epoxy acrylate curing film has photosensitivity under the irradiation of ultraviolet light and visible light, the curing can be completed without adding a photoinitiator, and meanwhile, the waterborne polyurethane/epoxy acrylate curing film prepared from the photosensitive waterborne polyurethane serving as the raw material has good thermal stability, strong adhesive force and impact strength, and good application prospect.

Description

A kind of preparation method of chalcone-terminated photosensitive water-based polyurethane/epoxy acrylate

technical field

The invention relates to the technical field of photocurable materials, in particular to a chalcone-terminated photosensitive water-based polyurethane/epoxy acrylate, a preparation method thereof, and a method for preparing a cured film of the water-based polyurethane acrylate.

Background technique

Polyurethane (PU) is a high molecular polymer containing repeating urethane (-NHCOO-) units, and the properties of PU are mainly composed of the structure of soft segment and hard segment. The hard segment is generally composed of isocyanate, which affects the physical properties of the material; the soft segment is generally composed of oligomeric polyol, which affects the flexibility and low-temperature properties of the material. PU is widely used in wood floor paint, paper paint, architectural paint, leather paint and many other fields. PU is divided into solvent-based polyurethane and water-based polyurethane. Solvent-based polyurethane adds organic solvents in the process of preparation, and there are certain safety hazards in the process of storage and transportation, and there are many organic pollutants discharged. Waterborne polyurethane is a polyurethane with water as the dispersed phase. Compared with solvent-based polyurethane, it has the advantages of low odor, low VOC emission, energy saving and environmental protection, good mechanical properties, and easy modification. It is widely used in the adhesive and coating industries. People's increasing awareness of environmental protection and the country's restrictions on solvent-based polyurethane make people's research on water-based polyurethane a hot spot.

Studies have shown that chalcones are α, β-unsaturated aromatic ketone flavanoids, which are the core of many important biological compounds. Chalcone and its derivatives have a wide range of pharmacological activities, among which antitumor, anti-inflammatory, antiulcer, antibacterial, and antioxidant activities have been reported. Chalcone contains α, β-unsaturated carbonyl groups as optically active functional groups, which are cross-linked by [2+2] cycloaddition of carbon-carbon double bonds under ultraviolet radiation.

Due to the use of UV curing, the light-cured polyurethane has better effects in reducing air pollution and energy saving, and meets the current development requirements of environmental protection, energy saving and safety materials, so it has also become the current development direction of polyurethane coatings. Chalcone has a photosensitive group, and there is no report on the introduction of chalcone into polyurethane.

SUMMARY OF THE INVENTION

Based on the above-mentioned technical background, the inventors made great progress, and found that: the chalcone-terminated photosensitive group was prepared by capping the polyurethane with chalcone and introducing the photosensitive group into the polyurethane chain through a covalent bond. The photosensitive waterborne polyurethane has excellent photocuring properties, and has photosensitivity under the irradiation of ultraviolet light and visible light, and can be cured without adding a photoinitiator. The waterborne polyurethane/epoxy acrylate cured film made of photosensitive waterborne polyurethane has good thermal stability, strong adhesion and impact strength, thereby completing the present invention.

A first aspect of the present invention is to provide a chalcone-terminated photosensitive water-based polyurethane prepared from raw materials including polyisocyanate, oligomer polyol and chalcone.

The second aspect of the present invention is to provide a preparation method of the chalcone-terminated photosensitive water-based polyurethane according to the first aspect of the present invention, the preparation method comprising the following steps:

Step 1. After the polyisocyanate, the oligomer polyol and the water-based chain extender are mixed and heated up, the reaction is carried out in the presence of a catalyst to obtain an isocyanate-terminated polyurethane;

Step 2, adding chalcone to the polyurethane obtained in step 1 to obtain a chalcone-terminated polyurethane;

Step 3, cooling, adding a neutralizer to react and then cooling, adding water for mixing to obtain a chalcone-terminated water-based polyurethane.

The third aspect of the present invention is to provide a chalcone-terminated photosensitive waterborne polyurethane/epoxy acrylate cured film, the waterborne polyurethane/epoxy acrylate cured film is made from photosensitive waterborne polyurethane and epoxy acrylate emulsion as raw materials Thus, the photosensitive water-based polyurethane is the chalcone-terminated photosensitive water-based polyurethane described in the first aspect of the present invention or the chalcone-terminated photosensitive water-based polyurethane prepared by the preparation method described in the second aspect of the present invention.

Description of drawings

Fig. 1 shows the absorbance change curve of embodiment 1 under different light sources;

Fig. 2 shows the absorbance curve of the products prepared in Example 1 and Example 2 under Led365nm ultraviolet lamp;

Fig. 3 shows the schematic diagram of crosslinking degree of the products obtained in Example 1 and Example 2 under different light intensities;

Figure 4 shows a schematic diagram of the degree of cross-linking of Example 1 and Example 2 in different solvents;

Figure 5 shows the TGA and DTG curves of the products prepared in Example 1 and Example 2.

Detailed ways

The present invention will be described in detail below, and the features and advantages of the present invention will become clearer and more definite along with the description.

Polyurethane main chain contains repeating -HNCOO- structural units, generally composed of soft segment monomer and hard segment monomer. By adjusting the ratio of hard segment and soft segment, thermosetting and thermoplastic polyurethane can be obtained. Water-based polyurethane is mainly prepared by the prepolymer method. The hydrophilic group is introduced into the polyurethane prepolymer terminated by -NCO. After chain extension, the polyurethane molecular chain is emulsified and dispersed in water.

A first aspect of the present invention is to provide a chalcone-terminated photosensitive water-based polyurethane prepared from raw materials including polyisocyanate, oligomer polyol and chalcone.

In the prior art, isocyanates can react with some weakly reactive hydrides, and the obtained products are stable at room temperature, and reverse reactions occur under certain conditions, namely "blocking" and "unblocking reactions". Polyisocyanate is a kind of special chemical with -N=C=O functional group, which mainly affects the mechanical properties of polyurethane materials.

In the present invention, polyisocyanate is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated benzyl diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate, preferably One or more selected from toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate, more preferably isophorone diisocyanate.

The oligomer polyol mainly affects the elasticity and low temperature properties of the material, and the oligomer polyol is selected from one or more of polyester polyol, polyether polyol and polycarbonate polyol.

Preferably, the oligomer polyol is selected from one or more of ethylene oxide glycol, polypropylene oxide glycol, polytetramethylene ether glycol and polytetrahydrofuran ether glycol. More preferably, the oligomer polyol is polytetrahydrofuran ether glycol. It has good low temperature resistance, hydrolysis resistance and mildew resistance.

The chalcone is selected from the group consisting of 4-β-hydroxyethyloxychalcone, 4-hydroxyethyloxy-4'-dimethylaminochalcone, 4-dimethylaminochalcone and 3-hydroxy-4 One or more of 'methoxychalcone, preferably selected from the one in 4-β-hydroxyethyl oxygen chalcone and 4-hydroxyethyl oxygen-4'-dimethylaminochalcone or both.

Chalcone is an α, β-unsaturated aromatic ketone-like flavanoid compound, and the double bond of chalcone can undergo dimerization reaction under the action of 300nm ultraviolet light or visible light irradiation. It has been found through experiments that the use of chalcone for end-capping in the polyurethane can make the polyurethane have α, β-unsaturated carbonyl optically active functional groups of chalcone, so that it can pass through the cycloaddition of carbon-carbon double bonds under ultraviolet irradiation. Cross-linked. The polyurethane also has high photoreactivity and complete photocrosslinking characteristics in the absence of photosensitizers.

The raw material includes the following components in parts by weight: based on 30 parts by weight of polyisocyanate,

40-75 parts by weight of oligomer polyol;

Chalcone 20-35 parts by weight.

Preferably, based on 30 parts by weight of polyisocyanate,

50-70 parts by weight of oligomer polyol;

22-30 parts by weight of chalcone;

More preferably, based on 30 parts by weight of polyisocyanate,

55-60 parts by weight of oligomer polyol;

Chalcone 24-26 parts by weight.

According to a preferred embodiment of the present invention, the raw material further includes an aqueous chain extender, and the aqueous chain extender is a substance containing an ionic group or an ionizable group that is introduced into the prepolymer during chain extension.

The water-based chain extender is selected from one or more of sulfonate type chain extenders, preferably selected from dimethylol propionic acid, dimethylol butyric acid, dimethylol valeric acid and dimethylol One or more of hexanoic acid, more preferably dimethylolpropionic acid with hydrophilic carboxyl group.

Based on 30 parts by weight of the polyisocyanate, the aqueous chain extender is 4-8 parts by weight, preferably 4.5-7 parts by weight, and more preferably 5-6 parts by weight.

The raw material also includes a neutralizing agent, which is selected from one or more of organic bases, preferably selected from diethanolamine, triethanolamine, triethylamine, N,N-dimethylisopropanolamine , one or more of triethylenediamine and dimethylcyclohexylamine, more preferably one or more of triethanolamine and triethylamine. Adding a certain amount of neutralizer can make the obtained water-based polyurethane more stable.

The neutralizing agent is 3 to 7 parts by weight, preferably 4 to 6 parts by weight, and more preferably 5 to 5.5 parts by weight, based on 30 parts by weight of the polyisocyanate. The addition of the neutralizing agent in the above weight portion can make the polyurethane have better thermal stability under the condition that other properties remain basically unchanged.

In the preparation process, a catalyst is also added, and the catalyst is selected from one or more of stannous octoate, tetramethylbutanediamine, triethylenediamine and dibutyltin dilaurate, preferably selected from tetramethylbutanedi One or both of amine and dibutyltin dilaurate, more preferably dibutyltin dilaurate. The addition of a catalyst allows the reaction to proceed rapidly.

The catalyst is 0.1-0.3 parts by weight, preferably 0.12-0.25 parts by weight, and more preferably 0.15-0.2 parts by weight, based on 30 parts by weight of the polyisocyanate.

Compared with the traditional solvent-based polyurethane, the chalcone-terminated water-based polyurethane of the present invention uses water instead of the organic solvent, which has the advantages of environmental protection, safety, and incombustibility. Good mechanical properties, good compatibility, no pollution, low VOC emissions, easy to operate and process. At the same time, the present invention prepares photosensitive waterborne polyurethane with high solid content by using chalcone to perform end-capping treatment on polyurethane molecules and introducing optically active groups into the polyurethane chain through covalent bonds, which has good photocuring performance. The waterborne polyurethane can achieve photocuring under ultraviolet light and visible light irradiation without adding a photoinitiator, and has good thermal stability.

At the same time, it is found that using the chalcone-terminated photosensitive water-based polyurethane as a raw material to prepare a cured film can also improve the adhesion and impact resistance of the cured film. The adhesive force of the cured film prepared by using the water-based polyurethane as a raw material can be increased to 0, and the impact resistance can be increased by 10 to 25 times.

The second aspect of the present invention is to provide a preparation method of the chalcone-terminated photosensitive water-based polyurethane according to the first aspect of the present invention, the preparation method comprising the following steps:

Step 1. After the polyisocyanate, the oligomer polyol and the water-based chain extender are mixed and heated up, the reaction is carried out in the presence of a catalyst to obtain an isocyanate-terminated polyurethane;

Step 2, adding chalcone to the polyurethane obtained in step 1 to obtain a chalcone-terminated polyurethane;

Step 3, cooling, adding a neutralizer to react and then cooling, adding water for mixing to obtain a chalcone-terminated water-based polyurethane.

The step is described and illustrated in detail below.

Step 1. After the polyisocyanate, the oligomer polyol and the water-based chain extender are mixed and heated up, the reaction is carried out in the presence of a catalyst to obtain an isocyanate-terminated polyurethane.

The polyisocyanate is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated benzyl diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate, preferably selected from toluene One or more of diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate, more preferably isophorone diisocyanate.

The oligomer polyol is selected from one or more of polyester polyol, polyether polyol and polycarbonate polyol. It is preferably one or more selected from ethylene oxide glycol, polypropylene oxide glycol, polytetramethylene ether glycol and polytetrahydrofuran ether glycol, more preferably polytetrahydrofuran ether glycol.

The aqueous chain extender is selected from one or more of the sulfonate type chain extenders, preferably selected from dimethylol propionic acid, dimethylol butyric acid, dimethylol valeric acid and dimethylol hexanoic acid One or more of the acids, more preferably dimethylolpropionic acid with a hydrophilic carboxyl group.

Preferably, after the water-based chain extender is dissolved in the solvent, it reacts with the polyisocyanate and the oligomer diol. After each substance is fully dissolved in the solvent, the dispersion is more uniform, and the reaction can be carried out more completely.

The solvent is selected from one or more of acetone, butanone and N-methylpyrrolidone. After the water-based chain extender is dissolved in the solvent, the water-based chain extender can be better mixed with other raw materials.

The catalyst is selected from one or more of stannous octoate, tetramethylbutanediamine, triethylenediamine and dibutyltin dilaurate, preferably selected from tetramethylbutanediamine and dibutyltin dilaurate. One or two, more preferably dibutyltin dilaurate. The addition of the above-mentioned catalysts enables the reaction to proceed rapidly.

In the present invention, based on 30 parts by weight of polyisocyanate,

40-75 parts by weight of oligomer polyol;

4-8 parts by weight of water-based chain extender;

Catalyst 0.1 to 0.3 parts by weight.

Preferably, based on 30 parts by weight of polyisocyanate,

50-70 parts by weight of oligomer polyol;

4.5-7 parts by weight of water-based chain extender;

Catalyst 0.12-0.25 parts by weight.

More preferably, based on 30 parts by weight of polyisocyanate,

55-60 parts by weight of oligomer polyol;

4.5-7 parts by weight of water-based chain extender;

Catalyst 0.15-0.2 parts by weight.

The amount of each substance will affect the mechanical properties of the final polyurethane. The inventors found that when the amount of polyisocyanate and oligomer polyol is in the above range, the obtained polyurethane has excellent performance while keeping other properties basically unchanged. Adhesion and good impact resistance.

In the present invention, the reaction is carried out under nitrogen protection to prevent the occurrence of side reactions, and the reaction temperature is 70-100°C, preferably 75-90°C, more preferably 80°C.

The reaction time is 2-5h, preferably 3-4h, more preferably 3.5h.

It is found through experiments that the photosensitive waterborne polyurethane prepared at this reaction temperature is more completely polymerized and has a higher degree of crosslinking.

Step 2, adding chalcone to the polyurethane obtained in step 1 to obtain a chalcone-terminated polyurethane.

The chalcone is selected from the group consisting of 4-β-hydroxyethyloxychalcone, 4-hydroxyethyloxy-4'-dimethylaminochalcone, 4-dimethylaminochalcone and 3-hydroxy-4 One or more of 'methoxychalcone, preferably selected from the one in 4-β-hydroxyethyl oxygen chalcone and 4-hydroxyethyl oxygen-4'-dimethylaminochalcone or both.

Chalcone is 20-35 parts by weight, preferably 22-30 parts by weight, more preferably 24-26 parts by weight, based on 30 parts by weight of the polyisocyanate.

The reaction temperature is 70-100°C, preferably 75-90°C, and more preferably 80°C.

The reaction time is 3-7h, preferably 4-6h, more preferably 5h.

In the present invention, the chalcone is introduced into the polyurethane, so that the polyurethane has an optically active functional group and is endowed with photocuring properties, so that the prepared polyurethane also has higher photoreactivity to ultraviolet light in the absence of a photosensitizer. Photocrosslinking properties. Compared with ordinary polyurethane curing, it is more energy-saving, environmentally friendly, green and efficient. At the same time, it was found that the introduction of chalcone also improved its impact resistance and the adhesion of the cured film.

Step 3, cooling, adding a neutralizer to react and then cooling, adding water for mixing to obtain a chalcone-terminated water-based polyurethane.

The temperature is lowered to 40 to 50° C. to carry out the reaction, preferably, the temperature is lowered to 40° C. to carry out the reaction.

The reaction time is 20-50 min, preferably the reaction time is 20-30 min.

The neutralizing agent is selected from one or more of the organic bases, preferably selected from diethanolamine, triethanolamine, triethylamine, N,N-dimethylisopropanolamine, triethylenediamine and dimethylamine One or more of cyclohexylamine, more preferably one or two of triethanolamine and triethylamine.

The neutralizing agent is 3 to 7 parts by weight, preferably 4 to 6 parts by weight, and more preferably 5 to 5.5 parts by weight, based on 30 parts by weight of the polyisocyanate.

The temperature is then lowered to 25-35°C, preferably 25-30°C, and water is added for mixing, and the mixing time is 1-2 hours, preferably 1 hour.

Mixing is carried out under high-speed stirring, so that water and water-based polyurethane are mixed evenly, and water is added to control the solid content of the polyurethane to be 30wt%-50wt%, preferably 35wt%-45wt%.

The rotational speed is 700 to 1000 r/min, preferably 800 r/min.

The third aspect of the present invention is to provide a chalcone-terminated photosensitive waterborne polyurethane/epoxy acrylate cured film, the waterborne polyurethane/epoxy acrylate cured film is made from photosensitive waterborne polyurethane and epoxy acrylate emulsion as raw materials have to.

The photosensitive water-based polyurethane is the chalcone-terminated photosensitive water-based polyurethane described in the first aspect of the present invention or the chalcone-terminated photosensitive water-based polyurethane prepared by the preparation method described in the second aspect of the present invention.

In the preparation process of the cured film, water is also added, and the mass ratio of the photosensitive water-based polyurethane, epoxy acrylate emulsion and water is (5-15): (1-30): (5-30), and the preferred mass ratio is ( 5-10): (1-3): (5-10).

According to a preferred embodiment of the present invention, the epoxy acrylate emulsion is composed of trimethylolpropane trimethacrylate, methyl methacrylate, epoxy resin in the presence of a siloxane coupling agent and a photoinitiator. Acrylate, acrylic acid and triethanolamine are obtained by photocuring. The light curing method is preferably ultraviolet light curing.

Based on 1-5 parts by weight of trimethylolpropane trimethacrylate, methyl methacrylate is 1-5 parts by weight, epoxy acrylate is 2-8 parts by weight, acrylic acid is 0.5-2 parts by weight, three The ethanolamine is 0.2-1.5 parts by weight, the siloxane coupling agent is 0.2-3 parts by weight, and the photoinitiator is 0.2-2 parts by weight.

The initiator is an ultraviolet light initiator, and the initiator is selected from 2-hydroxymethylphenylpropan-1-one, diethoxyacetophenone, 2-hydroxy-2-methyl-1-p-ethyl One or more of ether-based phenylacetone and isopropylthioxanthone, preferably 2-hydroxymethylphenylpropan-1-one. It has the advantages of high activity, high initiation efficiency, good solubility, low odor, low pollution and yellowing resistance. In addition, it has been found through experiments that adding the above-mentioned UV photoinitiator during the preparation of the cured film can effectively reduce the curing time. , more energy saving and environmental protection.

The siloxane coupling agent is preferably KH570

In the present invention, trimethylolpropane trimethacrylate acts as a diluent and is used as a solvent for reducing the viscosity of the reactant blend. During the experiment, it was found that the product obtained by using it as a diluent was The bonding density is moderate, the activity is high, the product obtained after light curing has good toughness, the impact resistance is improved, and the cost is reduced.

The chalcone-terminated photosensitive water-based polyurethane/epoxy acrylate is cured by ultraviolet light curing. Compared with the traditional thermal curing method, ultraviolet light curing has the characteristics of energy saving, environmental protection, green and high efficiency.

The water-based polyurethane/epoxy acrylate cured film is prepared by ultraviolet light curing, and the light curing time is 5-60 minutes, preferably 10-30 minutes.

Drying is preferably carried out before photocuring, preferably drying at 40-60°C for 20-30 hours, and then drying in a vacuum environment of 50-70°C for 20-30 hours. Drying can remove water, which not only helps to increase the speed of photocuring, but also helps to form a uniform and continuous cured film.

The cured film made of the water-based urethane acrylate of the present invention has strong adhesion and impact strength, the hardness of the cured film is small, between HB and 1B, and the gloss is between 135 and 191. Strong adhesion, grade 0 to 2, and contact angle between 65° and 90°.

The beneficial effects that the present invention has:

(1) In the present invention, the polyurethane molecules are end-capped with chalcone, and optically active groups are introduced into the polyurethane chain through covalent bonds to prepare a photosensitive water-based polyurethane, which has excellent photocuring properties;

(2) In the process of preparing the chalcone-terminated water-based polyurethane, the present invention replaces the organic solvent with water, retains the excellent performance of the traditional solvent-based polyurethane, and has the advantages of safety, combustion resistance, low odor, excellent mechanical properties, and good compatibility. , pollution-free, low VOC emissions and easy operation and processing;

(3) The water-based polyurethane of the present invention has good photocuring performance, and under the condition of no need to add a photoinitiator, it has photosensitivity under the radiation of ultraviolet light and visible light. Compared with the traditional thermal curing method, this The light curing method has the characteristics of energy saving, environmental protection, green and high efficiency;

(4) The cured film made of the water-based polyurethane of the present invention has good thermal stability, strong adhesion and impact resistance, and the cured film has less hardness and stronger adhesion;

(5) The preparation method provided by the present invention is simple, the conditions are mild, and the obtained product has good performance and good application prospect.

Example

The present invention is further described below through specific examples, which are only intended to illustrate the present invention, but are not intended to limit the scope of the present invention.

Example 1

Under nitrogen protection, 30g isophorone diisocyanate (IPDI), 56g polytetrahydrofuran ether diol (PTMG-1000), 5.6g dimethylol propionic acid (DMPA) were added to the container, and the temperature was raised to 80°C , add 0.17g dibutyltin dilaurate (DBTDL), react 3.5h, obtain isocyanate-terminated polyurethane;

25g of 4-β-hydroxyethyloxychalcone (HEOC) was added, the temperature was 80°C, and the reaction was carried out for 5h to obtain a chalcone-terminated water-based polyurethane;

Cool down to 40°C, add 5g TEA, and react for 20min-30min; then cool down to 25°C-30°C, add deionized water to control the solid content to be 40wt.%, and stir at high speed for 1h at a stirring speed of 800r/min to obtain char Ketone-terminated aqueous polyurethane emulsion PTMG-CWPU.

Example 2

The preparation was carried out in a similar manner to Example 1, except that the soft segment was 56 g polyethylene glycol (PEG-1000), and other steps were the same to obtain a chalcone-terminated aqueous polyurethane emulsion PEG-CWPU.

Example 3

Add 1.2 g of trimethylolpropane trimethacrylate, 2.8 g of methyl methacrylate, 2.7 g of epoxy acrylate, 0.58 g of acrylic acid, 0.28 g of KH5700, 0.27 g of photoinitiator, and 0.28 g of triethanolamine to the beaker. g, stir well and set aside. The epoxy acrylate emulsion was coated on the substrate, and then the cured film was obtained after illuminating in the air with an ultraviolet lamp, and cooled to room temperature for use. The cured film is marked as A1.

5 g of the chalcone-terminated aqueous polyurethane emulsion prepared in Example 1, 2 g of epoxy acrylate and 6.3 g of deionized water were added to the container and stirred until the emulsion was completely dispersed to obtain an aqueous polyurethane epoxy acrylate emulsion.

Coat the water-based polyurethane acrylate emulsion on the substrate, bake it in a constant temperature oven at 50 °C for 24 hours, take it out and dry it in a vacuum oven at 60 °C for 24 hours, and then illuminate it in the air with a UV lamp for 10 to 30 minutes to obtain water-based polyurethane/epoxy acrylic acid Ester cured film, cooled to room temperature for use. The waterborne polyurethane/epoxy acrylate cured film is designated B1.

Example 4

The preparation was carried out in the same manner as in Example 2, except that 1.2 g of trimethylolpropane trimethacrylate, 2.8 g of methyl methacrylate, 4 g of epoxy acrylate, and 0.7 g of acrylic acid were sequentially added to the beaker. , KH570 0.34g, photoinitiator 0.32g, triethanolamine 0.34g, stir evenly for later use. The lotion is marked 2. The epoxy acrylate emulsion was coated on the substrate, and then the cured film was obtained after illuminating in the air with an ultraviolet lamp, and cooled to room temperature for use. The cured film is marked A2.

5 g of the chalcone-terminated aqueous polyurethane emulsion prepared in Example 1, 2 g of epoxy acrylate and 6.3 g of deionized water were added to the container and stirred until the emulsion was completely dispersed. The resulting waterborne polyurethane/epoxy acrylate cured film is designated B2.

Example 5

The preparation was carried out in the same manner as in Example 2, except that 1.2 g of trimethylolpropane trimethacrylate, 2.8 g of methyl methacrylate, 6 g of epoxy acrylate, and 0.87 g of acrylic acid were sequentially added to the beaker. , KH570 0.42g, photoinitiator 0.4g, triethanolamine 0.43g, stir well for later use. The lotion is labeled 3. The epoxy acrylate emulsion was coated on the substrate, and then the cured film was obtained after illuminating in the air with an ultraviolet lamp, and cooled to room temperature for use. The cured film is marked A3.

5 g of the chalcone-terminated aqueous polyurethane emulsion prepared in Example 1, 2 g of epoxy acrylate and 6.3 g of deionization were added to the vessel until the emulsion was completely dispersed. The resulting waterborne polyurethane/epoxy acrylate cured film is designated B3.

Example 6

The preparation was carried out in a manner similar to that of Example 2, except that 1.6 g of trimethylolpropane trimethacrylate, 2.4 g of methyl methacrylate, 2.7 g of epoxy acrylate, and 0.58 g of acrylic acid were sequentially added to the beaker. g, KH5700.28g, photoinitiator 0.27g, triethanolamine 0.28g, stir evenly for later use. The cured film is marked A4.

5 g of the chalcone-terminated aqueous polyurethane emulsion prepared in Example 1, 2 g of epoxy acrylate and 6.3 g of deionized water were added to the container and stirred until the emulsion was completely dispersed. The resulting waterborne polyurethane/epoxy acrylate cured film is designated B4.

Example 7

The preparation was carried out in the same manner as in Example 2, except that 1.6 g of trimethylolpropane trimethacrylate, 2.4 g of methyl methacrylate, 4 g of epoxy acrylate, and 0.7 g of acrylic acid were sequentially added to the beaker. , KH570 0.34g, photoinitiator 0.32g, triethanolamine 0.34g, stir evenly for later use. The cured film is marked A5.

5 g of the chalcone-terminated aqueous polyurethane emulsion prepared in Example 1, 2 g of epoxy acrylate and 6.3 g of deionized water were added to the container and stirred until the emulsion was completely dispersed. The resulting waterborne polyurethane/epoxy acrylate cured film is designated B5.

Example 8

The preparation was carried out in a manner similar to that of Example 2, except that 1.6 g of trimethylolpropane trimethacrylate, 2.4 g of methyl methacrylate, 6 g of epoxy acrylate, and 0.87 g of acrylic acid were successively added to the beaker. , KH570 0.42g, photoinitiator 0.4g, triethanolamine 0.43g, stir well for use. The cured film is marked A6.

5 g of the chalcone-terminated aqueous polyurethane emulsion prepared in Example 1, 2 g of epoxy acrylate and 6.3 g of deionized water were added to the container and stirred until the emulsion was completely dispersed. The resulting waterborne polyurethane/epoxy acrylate cured film is designated B6.

Example 9

The preparation was carried out in a manner similar to that of Example 2, except that 2.8 g of trimethylolpropane trimethacrylate, 1.2 g of methyl methacrylate, 2.7 g of epoxy acrylate, and 0.58 g of acrylic acid were successively added to the beaker. g, KH5700.28g, photoinitiator 0.27g, triethanolamine 0.28g, stir evenly for later use. The cured film is marked A7.

5 g of the chalcone-terminated aqueous polyurethane emulsion prepared in Example 1, 2 g of epoxy acrylate and 6.3 g of deionized water were added to the container and stirred until the emulsion was completely dispersed. The resulting waterborne polyurethane/epoxy acrylate cured film is designated B7.

Example 10

The preparation was carried out in a manner similar to that of Example 2, except that 2.8 g of trimethylolpropane trimethacrylate, 1.2 g of methyl methacrylate, 4 g of epoxy acrylate, and 0.7 g of acrylic acid were sequentially added to the beaker. , KH570 0.34g, photoinitiator 0.32g, triethanolamine 0.34g, stir evenly for later use. The cured film is marked A8.

5 g of the chalcone-terminated aqueous polyurethane emulsion prepared in Example 1, 2 g of epoxy acrylate and 6.3 g of deionized water were added to the container and stirred until the emulsion was completely dispersed. The resulting waterborne polyurethane/epoxy acrylate cured film is designated B8.

Example 11

The preparation was carried out in the same manner as in Example 2, except that 2.8 g of trimethylolpropane trimethacrylate, 1.2 g of methyl methacrylate, 6 g of epoxy acrylate, and 0.87 g of acrylic acid were successively added to the beaker. , KH570 0.42g, photoinitiator 0.4g, triethanolamine 0.43g, stir well for use. The cured film is marked A9.

5 g of the chalcone-terminated aqueous polyurethane emulsion prepared in Example 1, 2 g of epoxy acrylate and 6.3 g of deionized water were added to the container and stirred until the emulsion was completely dispersed. The resulting waterborne polyurethane/epoxy acrylate cured film is designated B9.

Experimental example

Experimental Example 1

The photosensitivity test was carried out on the chalcone-terminated photosensitive water-based polyurethane prepared in Examples 1-2. The specific test process is as follows:

(1) Example 1 was sampled and dissolved in ethanol, followed by using GY-500 type high pressure mercury lamp, GY-500 type high pressure mercury lamp and ZWB2 filter to intercept 365nm ultraviolet light, GY-500 type high pressure mercury lamp and 254nm filter The light sheet intercepts 254nm ultraviolet light, GY-500 high pressure mercury lamp plus JB420 filter intercepts 420nm visible light, Led365nm ultraviolet light, Led395nm ultraviolet light, and 254nm ultraviolet germicidal lamp as the radiation source, and uses a UV-visible spectrophotometer to record the change in absorbance. Figure 1.

(2) Samples of Examples 1 and 2 were dissolved in ethanol solution respectively, and smeared on the cuvette, the solvent was volatilized to form a film at room temperature, and the Led 365nm ultraviolet lamp was used as the radiation light source, and recorded on the ultraviolet-visible spectrophotometer The absorbance changes, as shown in Figure 2.

)。(3) Examples 1 and 2 were dissolved in an ethanol solution, and a Led365nm ultraviolet lamp was used as a light source to test the degree of photocrosslinking under different light intensities, as shown in Figure 3. Light (calculation method of cross-linking degree:

).

(4) Embodiments 1 and 2 are dissolved in different solvents (1,4-dioxane, tetrahydrofuran, dichloromethane, chloroform), and a Led 365nm ultraviolet lamp is used as a radiation source, and the degree of photocrosslinking changes As shown in Figure 4.

It can be seen from FIG. 1 that the photosensitive water-based polyurethane prepared by the present invention can realize photocuring under both ultraviolet light and visible light, and the photocuring performance is good.

It can be seen from FIG. 2 that the photosensitive water-based polyurethane prepared in Example 1 and Example 2 of the present invention both have good photocuring properties under ultraviolet light irradiation.

Figures 3(a) and 3(b) respectively show the degree of crosslinking of the photosensitive water-based polyurethane prepared in Example 1 and Example 2 under different light intensities. It can be seen that the photosensitive water-based polyurethane prepared by the present invention increases with With the increase of the light intensity, the degree of cross-linking increases gradually.

Figures 4(a) and 4(b) respectively show the degree of crosslinking of the photosensitive water-based polyurethane prepared in Example 1 and Example 2 in different solvents. The obtained water-based polyurethane has good cross-linking degree in different solvents, which can basically reach 100%.

Experimental Example 2 Thermal Stability Test

The thermal stability of the products prepared in Example 1 and Example 2 was tested, and the specific test process was as follows: in a nitrogen atmosphere, the heating rate was 10°C/min, and the temperature of the test sample was 0-600°C. A Q600 thermogravimetric analyzer was used to record the TGA and DTG change curves of Example 1 and Example 2, as shown in Figure 5.

Figure 5(a) shows the TGA and DTG curves of the product prepared in Example 1, and Figure 5(b) shows the TGA and DTG curves of the product prepared in Example 2.

It can be seen from Figure 5 that the photosensitive water-based polyurethane capped by chalcone has good thermal stability, and after photocuring, it still has good thermal stability.

Experimental example 3

The impact strength of the epoxy acrylate cured films and water-based polyurethane acrylate cured films prepared in Examples 3 to 11 was measured, and the specific steps were as follows:

(1) Before use, check whether the center of the impact rod is consistent with the center of the concave hole on the impactor base. If there is any deviation, adjust the inner hexagonal screw on the impactor base.

(2) Check whether the alignment mark is aligned with the zero line, gently lower the impact hammer, and observe whether the positioning line coincides with the zero line. If there is any deviation, adjust the screws on both sides of the positioning mark.

(3) Lift the impact hammer with the right hand, and place the cured film tinplate sample on the pillow block with the left hand, and the impact point is not less than 15mm from the edge of the detection plate.

(4) According to the stipulations in the product standard, fix the height of the impact hammer, let go of the impact hammer and drop it on the cured film sample plate.

(5) Move the sample plate of the cured film repeatedly so that the impact hammer falls on different positions of the sample plate, and report the maximum height at which the coating film does not crack or come off. The test results are shown in Table 1 and Table 2.

Table 1

Table 2

It can be seen from Table 1 and Table 2 that the hardness of the waterborne polyurethane/epoxy acrylate cured film is reduced, and the impact strength (the range of the instrument is 0-50cm) is greatly improved.

It is further explained that the impact strength of the waterborne polyurethane/epoxy acrylate cured film obtained by adding the photosensitive waterborne polyurethane described in the present application is significantly improved compared to the cured film without the addition of the waterborne polyurethane.

Experimental example 4

The properties of epoxy acrylate cured films and waterborne polyurethane acrylate cured films prepared in Examples 3 to 11 were analyzed. The specific test performance and test process are as follows:

(1) Determination of gel content of cured film

Take the cured film sample and weigh it. After soaking in acetone for 12 h, replace the acetone solution and continue soaking for 12 h, filter off the solution, dry to constant weight, and record the weight.

Gel content (%)=(mass after acetone soaking/mass before acetone soaking)×100%.

(2) Determination of hardness of cured film: This experiment was determined according to GB/T1730-1993 standard.

(3) Determination of gloss of cured film: ETB-0686 gloss meter.

(4) Hardness of cured film: GB/T1730-1993 standard.

(5) Adhesion of cured film: GB/T9286-1998 standard.

(6) Contact angle of cured film: JC2000D1 contact angle measuring instrument.

Table 1 and Table 2 show the performance analysis of epoxy acrylate cured films and waterborne polyurethane acrylate cured films prepared in Examples 3 to 11 of the present invention.

From Tables 1 and 2, it can be seen that the hardness of the waterborne polyurethane/epoxy acrylate cured film is reduced, and the adhesion is greatly improved.

It is further explained that the adhesive force of the waterborne polyurethane/epoxy acrylate cured film obtained by adding the photosensitive waterborne polyurethane described in this application is significantly improved compared to the cured film without waterborne polyurethane. The adhesive force of the water-based polyurethane/epoxy acrylate cured film prepared by the present invention can reach the highest level of 0, and there is basically no peeling after cross-cutting.

The present invention has been described in detail above in conjunction with specific embodiments and exemplary examples, but these descriptions should not be construed as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, various equivalent replacements, modifications or improvements can be made to the technical solutions of the present invention and the embodiments thereof, which all fall within the scope of the present invention. The scope of protection of the present invention is determined by the appended claims.

Claims (10)

1. A chalcone-terminated photosensitive water-based polyurethane, characterized in that, the photosensitive water-based polyurethane is prepared from raw materials comprising polyisocyanate, oligomer polyol and chalcone. 2. photosensitive water-based polyurethane according to claim 1, is characterized in that, based on the polyisocyanate of 30 parts by weight, 40-75 parts by weight of oligomer polyol; Chalcone 20-35 parts by weight. 3. photosensitive water-based polyurethane according to claim 1, is characterized in that, The oligomer polyol is selected from one or more of polyester polyol, polyether polyol and polycarbonate polyol; Chalcone is selected from the group consisting of 4-β-hydroxyethyloxychalcone, 4-hydroxyethyloxy-4'-dimethylaminochalcone, 4-dimethylaminochalcone and 3-hydroxy-4'methylaminochalcone One or more of oxychalcone. 4. photosensitive water-based polyurethane according to claim 1, is characterized in that, described raw material also comprises water-based chain extender, and described water-based chain extender is selected from one or more in sulfonate type chain extender ; The water-based chain extender is 4-8 parts by weight based on 30 parts by weight of the polyisocyanate. 5. The photosensitive water-based polyurethane according to claim 1, wherein the raw material also comprises a neutralizing agent, and the neutralizing agent is selected from one or more of organic bases; The neutralizing agent is 3 to 7 parts by weight based on 30 parts by weight of the polyisocyanate. 6. photosensitive water-based polyurethane according to claim 1, is characterized in that, The water-based polyurethane can realize photocuring under the irradiation of ultraviolet light and visible light without adding a photoinitiator; The adhesive force of the cured film prepared by using the water-based polyurethane as a raw material can be increased to 0, and the impact resistance can be increased by 10 to 25 times. 7. the preparation method of the photosensitive water-based polyurethane described in one of claim 1 to 6, is characterized in that, described preparation method comprises the following steps: Step 1. After the polyisocyanate, the oligomer polyol and the water-based chain extender are mixed and heated up, the reaction is carried out in the presence of a catalyst to obtain an isocyanate-terminated polyurethane; Step 2, adding chalcone to the polyurethane obtained in step 1 to obtain a chalcone-terminated polyurethane; Step 3, cooling, adding a neutralizer to react and then cooling, adding water for mixing, to obtain a chalcone-terminated water-based polyurethane. 8. preparation method according to claim 7, is characterized in that, in step 1, The reaction temperature is 70～100°C, and the reaction time is 2～5h; In step 2, the reaction temperature is 70-100° C., and the reaction time is 3-7 h. 9. preparation method according to claim 7, is characterized in that, in step 3, Cool to 40～50 ℃ to carry out the reaction, and the reaction time is 20～50min; The temperature is then lowered to 25 to 35°C, and the mixing time is 1 to 2 hours. 10. A chalcone-terminated photosensitive water-based polyurethane/epoxy acrylate cured film is characterized in that, this water-based polyurethane/epoxy acrylate cured film is made from photosensitive water-based polyurethane and epoxy acrylate emulsion as raw materials ; The photosensitive waterborne polyurethane is the photosensitive waterborne polyurethane described in any one of claims 1 to 6 or the photosensitive waterborne polyurethane prepared by the preparation method described in any one of claims 7 to 9.

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