WO2023098394A1 - Optical-grade oleophilic thermal repair resin, preparation method thereof and self-repairing coating layer - Google Patents

Abstract

Disclosed in the invention are an optical-grade oleophilic thermal repair resin, a preparation method thereof and a self-repairing coating layer. The preparation method comprises the following steps: (1) reacting polyether polyol and aliphatic isocyanate to generate an isocyanate-terminated polyurethane prepolymer; (2) adding caprolactone-grafted acrylate to react with the polyurethane prepolymer in step (1) to prepare an intermediate; and (3) adding polyhydroxy polyacrylate, bifunctional acrylate, and acrylate phosphate to carry out polymerization reaction under the action of an initiator to prepare a thermal repair resin. The thermal repair resin is used as a main resin of a thermal repair coating layer. The coating layer obtained after the resin curing reaction can undergo self-repairing under a heating condition. The resin has a high stain resistance, a compact coating layer surface, oleophilic properties, a water contact angle within 80°, and high stain permeation resistance. Excellent applications can be obtained on invisible car cover films and car body color-changing films.

Description

A kind of optical grade lipophilic thermal repair resin and its preparation method and self-repair coating technical field

The present application relates to the technical field of polymer materials, and more specifically relates to an optical-grade lipophilic thermal repair resin, a preparation method thereof, and a self-repair coating.

Background technique

Automobile paint protection film, commonly known as car coating film, when used, it is pasted on the paint surface of the car body to protect the car paint, and has the functions of anti-scratch, stain resistance, environmental corrosion resistance, and beautiful decoration. The surface of the car coating film is generally coated with self-repairing paint. When the car body is scratched or slightly bumped, as long as the car coating base film itself is not damaged, small scratches can be automatically eliminated in a short time (second repair), Or eliminate it under heat conditions (thermal repair); when the base film of the car coating film is damaged by a serious collision, the car coating film can be partially replaced. Therefore, the self-repairing car coating film can effectively protect the car paint, reduce the trouble of repairing the car paint, and avoid the environmental pollution caused by repairing the car paint; it can also make the car body more beautiful, improve the value preservation rate of the car, and satisfy people's personalization Demand, welcomed by the market.

The most critical material in the self-healing car coating film is the self-healing coating, and the performance of the coating determines the grade difference of the car coating film. The high-grade car coating film not only has good self-repair performance, but also has strong stain resistance. Dust, bird droppings, oil stains, water spots and other stains can be easily removed, and it has strong weather resistance and yellowing resistance, and its service life can reach 3 to 5 years. above. These excellent properties are basically realized by the outermost self-healing coating, and the core of the self-healing coating is the self-healing resin synthesis technology.

Car film self-repairing resins are usually heat-curing. The resin contains a large number of hydroxyl groups, which can react with curing agents to increase cross-linking density, thereby improving stain resistance. In terms of repair methods, there are two types: instant repair and hot repair. The second repair type does not require external influences, and scratches can usually be repaired within 10 to 30 seconds; the hot repair type requires hot water or hot air above 60°C It acts on scratches and can be repaired after about 10 to 60 seconds. Most of the early car coating films were repaired in seconds, but this kind of resin was soft and not dense enough, which affected the stain resistance; therefore, most of the market has turned to thermal repair. When there are scratches on the surface, the car body will , and quickly repaired itself.

Due to the different molecular structures in the resin, self-healing coatings have a type of hydrophobic and oleophobic type (water contact angle of 100° or more), and a type of lipophilic type (water contact angle of 60-80°). The difference is that the molecular structure of the hydrophobic and oleophobic resin is relatively sparse, mainly relying on the fluorine and silicon groups on the surface of the resin to block the stains, but as time goes by, the stains will still slowly penetrate into the coating through the molecular gap. I can't wash it off. Oleophilic resin does not contain fluorine and silicon elements, the tentacles of water are relatively low, and the structure is relatively dense. Stains and dust are generally adsorbed on the surface of the coating; it is very simple to remove. Generally, the stains can be easily removed by washing with rain or wiping when washing the car. Dust removed without penetration.

At present, the oleophobic self-healing coating products on the market are still popular, and the oleophilic products have just come out, and there is still a lack of related corresponding technologies. Patent CN 104356338B discloses a method for preparing a self-repairing polyurethane coating, which uses a hydrophilic polyol to synthesize a hydrophilic polyurethane, and introduces methylcytosine containing amino groups and hydroxyl groups, so that the coating has a repairing function; but This resin is also limited to use on metal or medical devices and cannot be used in car wraps.

application content

In order to overcome the defects of the prior art, the application provides a method for preparing an optical-grade lipophilic thermal repair resin, comprising steps:

(1) Using polyether polyols and aliphatic isocyanates to react to generate isocyanate-terminated polyurethane prepolymers;

(2) Adding caprolactone-grafted hydroxyacrylate to react with the polyurethane prepolymer in step (1) to prepare an intermediate;

(3) Add polyhydroxy polyacrylate, difunctional acrylate, and acrylate phosphate, and carry out polymerization reaction under the action of an initiator to prepare a thermal repair resin.

Compared with the prior art, in the technical solution of this application, polyether polyol and isocyanate are firstly used to react to synthesize polyurethane skeleton, so that the molecular weight of the overall resin is rapidly increased, making the final resin soft and elastic, and it is easier to realize the heat repair function. Among them, polyether polyol has good hydrolysis resistance and excellent hydrophilicity, which can increase surface energy; aliphatic isocyanate has good yellowing resistance. If aromatic isocyanate is used and phenyl is introduced, the thermal repair resin will not be resistant to yellowing. Change. Next, the hydroxyl acrylate grafted with caprolactone reacts with the polyurethane prepolymer, and the hydroxyl reacts with isocyanate to introduce acrylate double bonds to increase the molecular weight and make the resin more tough. Finally, polyhydroxyl polyacrylate, difunctional acrylate, and acrylate phosphate are added. Among them, the difunctional acrylate has two acrylic acid double bond groups, and a chain extension reaction occurs to further expand the molecular weight. At the same time, its alcohol condensation group Groups can improve the hydrophilicity of the resin and increase the surface energy. Acrylate phosphate can participate in the reaction of acrylic acid, and its phosphate group can also improve the hydrophilicity and temperature resistance of the resin, and also has a plasticizing effect, making the resin elastic, thereby improving the thermal repair effect. Multi-hydroxy polyacrylate, difunctional acrylate, acrylate phosphate and various types of acrylate monomers are used in combination to form a three-dimensional cross-network structure and retain hydroxyl groups. The hydroxyl groups undergo thermosetting reactions with isocyanate curing agents to obtain Self-healing coating makes the coating denser and can effectively prevent stains from penetrating. The thermal repair resin of the present application can not only achieve self-repair under heat conditions, but also has strong stain resistance, dense coating surface, lipophilicity, and water contact angle within 80°. In addition, the preparation method does not require a special high-temperature environment or a special inert atmosphere, and has simple process, high production efficiency and low cost.

Preferably, the polyether polyol is selected from at least one of polyoxypropylene glycol (PPG), polyethylene glycol (PEG), and polytetrahydrofuran glycol (PTMG).

Preferably, the molecular weight of the polyether polyol is 1000-2000. If the molecular weight is too small, the molecular weight of the resin obtained is not large enough, and if the molecular weight is too large, the polymerization reaction may be difficult.

Preferably, the aliphatic isocyanate is selected from hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (HMDI), cyclohexane dimethylene diisocyanate (HXDI), methyl cyclohexyl diisocyanate (HTDI) at least one.

Preferably, the difunctional acrylate is selected from tripropylene glycol diacrylate (TRPGDA), ethylene glycol dimethacrylic acid (EGDMA), ethylene glycol diacrylate (EGDA), 1,6-hexane At least one of diol diacrylate (HDODA).

Preferably, the acrylate phosphate is selected from at least one of hydroxyethyl methacrylate phosphate (HEMAP) and methacrylate phosphate (MAP).

Preferably, the polyhydroxy polyacrylate is selected from 2,3-dihydroxypropyl acrylate (DHPA), 2-methyl-2-acrylic acid-2,3-dihydroxypropyl (GMMA), glycerol 1, 3-Diglyceryl alkyd diacrylate (80MFA), glyceryl triacrylate (allnex OTA-480), trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate at least one of the Preferably, polyhydroxy polyacrylates containing at least two active hydroxyl groups are used, such as 2,3-dihydroxypropyl acrylate (DHPA), 2-methyl-2-propenoic acid-2,3-dihydroxypropyl ( GMMA), glycerol 1,3-diglyceryl alkyd diacrylate (80MFA), glyceryl triacrylate (allnex OTA-480). Using the above-mentioned polyhydroxy polyacrylate, it has strong hydrophilicity and better stain resistance.

Preferably, the initiator is azobisisobutyronitrile (AIBN).

Preferably, the caprolactone-grafted hydroxyacrylate is selected from at least one of FA1DDM or FA2D of Japan Daicel Chemical.

Preferably, the preparation method of polyurethane prepolymer comprises:

Put a certain amount of polyether polyol into the reaction kettle, raise the temperature to 120°C, vacuum dehydrate for 2-3 hours, cool down to 75-82°C, and then add aliphatic isocyanate (the molar ratio of polyether polyol to aliphatic isocyanate is 1:1.05), stirred and reacted for 2 to 4 hours to obtain an isocyanate-terminated polyurethane prepolymer.

Preferably, the preparation method of the intermediate comprises:

Add the hydroxyacrylate of caprolactone grafting in the polyurethane prepolymer, the mol ratio of the hydroxyacrylate of caprolactone grafting and aliphatic isocyanate is 0.1: 1, and drip concentration is the catalyst solution of 0.1% (solution quality Equivalent to 50-80% of polyester polyol). Turn on the condensing reflux device, add dropwise for 1 hour, and continue the reaction for 1-2 hours to obtain the intermediate.

Wherein, the catalyst is selected from dibutyltin dilaurate; the solvent is selected from ethyl acetate, toluene, butyl acetate, butanone, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, methyl isobutyl ketone, cyclohexane One or more of ketones.

Preferably, the preparation method of thermal restoration resin comprises the steps of:

1. Fully stir and mix one or more polyhydroxy acrylate monomers, one or more difunctional acrylate monomers, and one or more acrylate phosphate monomers at room temperature to obtain a mixture monomer;

2. Dissolving the initiator in an organic solvent to obtain an initiator solution.

3. First add 1/2 mixed monomer and 1/10 initiator solution into the intermediate reaction kettle, turn on the heating system and condensation reflux device, at a temperature of 78-85°C, and a stirring speed of 60-120r/min The reaction was stirred for 2 h under the conditions. Add the remaining 1/2 mixed monomer and 1/2 initiator solution dropwise for 30-60 minutes, and continue to react for 2 hours. Add the final 2/5 initiator solution dropwise for 30-60 minutes, and continue the reaction for 2-3 hours. Turn off the heating system and condensing reflux device, keep stirring at a speed of 60r/min, cool to room temperature, and then filter through a 100-200 mesh filter element to obtain a self-repairing resin.

Preferably, in the preparation method, the raw materials for the preparation of the thermal restoration resin, in parts by weight, include:

Correspondingly, the present application also provides an optical-grade hydrophobic and oleophobic thermal restoration resin, which is prepared by the above-mentioned preparation method of the optical-grade lipophilic thermal restoration resin.

Correspondingly, the present application also provides a self-healing coating, including an isocyanate curing agent and the above-mentioned optical-grade lipophilic heat-repairing resin. Due to the high degree of polymerization, high molecular weight, high transparency, low glass transition temperature, and strong flexibility of the heat repair resin, it has excellent heat repair resilience, so it is used as the main resin of the heat repair coating. It can be self-repaired under heat conditions; the resin has strong stain resistance, the coating surface is dense, and has lipophilicity, the water contact angle is within 80°, and the ability to resist stain penetration is strong. The self-healing coating is coated on TPU, PVC and other material films to be used in the field of automobile paint protection film, and can be well applied in invisible car coating film and car body color changing film.

Detailed ways

The following examples are intended to illustrate the content of the present application, but not to limit the protection scope of the claims of the present application.

Example 1

A preparation method of an optical-grade lipophilic thermal repair resin, comprising the steps of:

(1) Put 200kg of polyoxypropylene diol into the reaction kettle, raise the temperature to 120°C, vacuum dehydrate for 2-3 hours, cool down to 75-82°C, then add hexamethylene diisocyanate, polyoxypropylene diol and hexa The molar ratio of methylene diisocyanate is 1:1.05, and the reaction is stirred for 2 to 4 hours to obtain an isocyanate-terminated polyurethane prepolymer;

(2) Add FA1DDM in the polyurethane prepolymer, the mol ratio of FA1DDM and hexamethylene diisocyanate is 0.1: 1, dropwise concentration is the dibutyltin dilaurate solution (solution quality 120kg) of 0.1%, open condensation reflux device, add dropwise for 1 hour, and continue to react for 1 to 2 hours to obtain the intermediate;

(3) The obtained intermediate is set to 100 parts, and 5 parts of 2,3-dihydroxypropyl acrylate, 2 parts of tripropylene glycol diacrylate, and 2 parts of hydroxyethyl methacrylate phosphate are fully stirred at room temperature Mix to obtain mixed monomers;

1 part of initiator azobisisobutyronitrile was dissolved in 75 parts of ethyl acetate to obtain initiator solution;

First add 1/2 mixed monomer and 1/10 initiator solution into the reaction kettle of the intermediate, turn on the heating system and the condensation reflux device, under the condition that the temperature is 78-85°C and the stirring speed is 60-120r/min The reaction was stirred for 2h. Add the remaining 1/2 mixed monomer and 1/2 initiator solution dropwise for 30-60 minutes, and continue to react for 2 hours. Add the final 2/5 initiator solution dropwise for 30-60 minutes, and continue the reaction for 2-3 hours. Turn off the heating system and condensing reflux device, keep stirring at a speed of 60r/min, cool to room temperature, and then filter through a 100-200 mesh filter element to obtain a self-repairing resin.

Example 2

A preparation method of an optical-grade lipophilic thermal repair resin, comprising the steps of:

(1) Put 200kg of polytetrahydrofuran diol into the reaction kettle, raise the temperature to 120°C, vacuum dehydrate for 2-3 hours, cool down to 75-82°C, then add isophorone diisocyanate, polytetrahydrofuran diol and isophor The molar ratio of ketone diisocyanate is 1:1.05, and the reaction is stirred for 2 to 4 hours to obtain an isocyanate-terminated polyurethane prepolymer;

(2) Add FA2D in the polyurethane prepolymer, the mol ratio of FA2D and isophorone diisocyanate is 0.1: 1, dropwise concentration is the dibutyltin dilaurate solution (solution quality 110kg) of 0.1%, open condensation reflux device, add dropwise for 1 hour, and continue to react for 1 to 2 hours to obtain the intermediate;

(3) The obtained intermediate is set as 100 parts, and 10 parts of glycerin 1,3-diglycerol diacrylate, 4 parts of ethylene glycol diacrylate, and 2 parts of methacrylate phosphate are fully stirred and mixed at room temperature get mixed monomer;

1 part of initiator azobisisobutyronitrile was dissolved in 75 parts of ethyl acetate to obtain initiator solution;

First add 1/2 mixed monomer and 1/10 initiator solution into the reaction kettle of the intermediate, turn on the heating system and the condensation reflux device, under the condition that the temperature is 78-85°C and the stirring speed is 60-120r/min The reaction was stirred for 2h. Add the remaining 1/2 mixed monomer and 1/2 initiator solution dropwise for 30-60 minutes, and continue to react for 2 hours. Add the final 2/5 initiator solution dropwise for 30-60 minutes, and continue the reaction for 2-3 hours. Turn off the heating system and condensing reflux device, keep stirring at a speed of 60r/min, cool to room temperature, and then filter through a 100-200 mesh filter element to obtain a self-repairing resin.

Example 3

A preparation method of an optical-grade lipophilic thermal repair resin, comprising the steps of:

(1) Put 200kg polyethylene glycol into the reaction kettle, heat up to 120°C, vacuum dehydrate for 2-3 hours, cool down to 75-82°C, then add hexamethylene diisocyanate, polyethylene glycol and hexamethylene The molar ratio of the base diisocyanate is 1:1.05, and the reaction is stirred for 2 to 4 hours to obtain an isocyanate-terminated polyurethane prepolymer;

(2) Add FA1DDM in the polyurethane prepolymer, the molar ratio of FA1DDM and hexamethylene diisocyanate is 0.1: 1, and the dibutyltin dilaurate solution (solution quality 125kg) that concentration is 0.1% is added dropwise. Turn on the condensing reflux device, add dropwise for 1 hour, and continue the reaction for 1 to 2 hours to obtain the intermediate;

(3) The obtained intermediate is set to 100 parts, 10 parts of glycerolated triacrylate, 1 part of 2,3-dihydroxypropyl acrylate, 2 parts of 1,6-hexanediol diacrylate, 1 part of hydroxyethyl Methacrylate phosphate and 1 part of methacrylate phosphate are fully stirred and mixed at room temperature to obtain a mixed monomer;

1 part of initiator azobisisobutyronitrile was dissolved in 75 parts of ethyl acetate to obtain initiator solution;

First, add 1/2 mixed monomer and 1/10 initiator solution into the reaction kettle of the intermediate, turn on the heating system and the condensation reflux device, under the condition that the temperature is 78-85°C and the stirring speed is 60-120r/min The reaction was stirred for 2h. Add the remaining 1/2 mixed monomer and 1/2 initiator solution dropwise for 30-60 minutes, and continue to react for 2 hours. Add the final 2/5 initiator solution dropwise for 30-60 minutes, and continue the reaction for 2-3 hours. Turn off the heating system and condensing reflux device, keep stirring at a speed of 60r/min, cool to room temperature, and then filter through a 100-200 mesh filter element to obtain a self-repairing resin.

Example 4

This embodiment is basically the same as that of Embodiment 1, except that trimethylolpropane triacrylate is selected as the polyhydroxy polyacrylate in Embodiment 4, while 2,3-dihydroxypropyl acrylate is selected in Embodiment 1.

Comparative example 1

This comparative example is basically the same as Example 1, except that in Comparative Example 1, difunctional acrylate (tripropylene glycol diacrylate) is replaced by monofunctional acrylate (hydroxyethyl methacrylate), and the rest It is the same as in Example 1, and will not be described in detail here.

Comparative example 2

This comparative example is basically the same as that of Example 1, except for the lack of acrylate phosphate in Comparative Example 2, and the rest is the same as that of Example 1, which will not be described in detail here.

Application Test Methodology and Results:

1. Compound the thermal repair resin and isocyanate curing agent (Covestro N3390) at a ratio of 2:1 to 5:1, add n-BAC solvent to dilute, then add other additives, stir evenly to obtain a self-healing coating .

2. Coating the self-healing coating on a transparent PET film with a coating thickness of 25 μm, drying the solvent and aging to make a self-healing film, and testing the surface properties of the coating. The results are shown in Table 1.

Among them, the adhesion is measured by the hundred grid method, and the test standard is GB/T 33049-2016;

The water contact angle is measured by a contact angle tester, and the test standard is GB/T 30693-2014;

The light transmittance and haze are measured by a light transmittance haze meter, and the test standard is GB/T 2410-2008;

The thermal repair performance is measured by the copper brush method, and the test method refers to the test method in "HG/T 5675-2020 Optical Functional Thin Film Self-Repair Hardening Film";

Anti-fouling performance test method: refer to the test method in the standard "T/GDEIA 17-2021 Self-healing transparent film for protecting automobile paint surface", draw a horizontal line on the coating with Chenguang 2110 marker pen, observe the shape of the handwriting, and keep the handwriting for 1min Finally, wipe it with a cotton swab dipped in methyl ethyl ketone, and observe whether there are handwriting residues on the coating.

Table 1 Test results

From the test results in Table 1, it can be seen that the thermal repair resin prepared by the technical solution of the present application is used as the main resin of the thermal repair coating, and the coating after the resin curing reaction can be self-repairing under heat conditions; the resin has strong stain resistance, and the coating The surface is dense and lipophilic, the water contact angle is within 80°, and the ability to resist stain penetration is strong.

Compared with Example 4, Example 1 uses polyhydroxyl polyacrylate with two active hydroxyl groups, which has strong hydrophilicity and better stain resistance.

Comparative Example 1 adopts monofunctional acrylate, which does not produce a cross network structure and reduces the stain resistance.

In Comparative Example 2, acrylate phosphate is lacking, the resin is slightly harder, and the heat repair speed is reduced.

The above description is only a preferred embodiment of the application, and does not limit the application in any form. Although the application has disclosed the above with the preferred embodiment, it is not used to limit the application. Any technical field that has Ordinary knowledgeable persons, without departing from the scope of the technical solution of the present application, can use the technical content disclosed above to make some changes or modifications to equivalent embodiments with equivalent changes, but if they do not depart from the technical solution of the present application, according to Any simple modifications, equivalent changes and modifications made to the above embodiments by the technical essence of the present application still fall within the scope of the technical solutions of the present application.

Claims (10)

A preparation method of an optical-grade lipophilic thermal repair resin, characterized in that it comprises the steps of: (1) Using polyether polyols and aliphatic isocyanates to react to generate isocyanate-terminated polyurethane prepolymers; (2) Adding caprolactone-grafted hydroxyacrylate to react with the polyurethane prepolymer in step (1) to prepare an intermediate; (3) Add polyhydroxy polyacrylate, difunctional acrylate, and acrylate phosphate, and carry out polymerization reaction under the action of an initiator to prepare a thermal repair resin. The preparation method of optical grade lipophilic heat repair resin as claimed in claim 1, is characterized in that, described polyether polyol is selected from at least one in polyoxypropylene diol, polyethylene glycol, polytetrahydrofuran diol kind. The preparation method of optical-grade lipophilic thermal repair resin according to claim 1, characterized in that the molecular weight of the polyether polyol is 1000-2000. The preparation method of optical grade lipophilic type thermal restoration resin as claimed in claim 1, is characterized in that, described aliphatic isocyanate is selected from hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate , cyclohexane dimethylene diisocyanate, methyl cyclohexyl diisocyanate at least one. The preparation method of optical grade lipophilic heat repair resin as claimed in claim 1, is characterized in that, described difunctionality acrylate is selected from tripropylene glycol diacrylate, ethylene glycol dimethacrylic acid, ethylene dimethacrylate At least one of alcohol diacrylate and 1,6-hexanediol diacrylate. The preparation method of optical grade lipophilic type thermal restoration resin as claimed in claim 1, is characterized in that, described acrylate phosphate is selected from at least in hydroxyethyl methacrylate phosphate, methacrylate phosphate A sort of. The preparation method of optical grade lipophilic type thermal restoration resin as claimed in claim 1, is characterized in that, described polyhydroxy polyacrylate is selected from 2,3-dihydroxy propyl acrylate, 2-methyl-2-acrylic acid - At least one of 2,3-dihydroxypropyl ester, glycerol 1,3-diglyceryl alkyd diacrylate, and glyceryl triacrylate. The preparation method of optical-grade lipophilic thermal repair resin according to claim 1, wherein the initiator is selected from azobisisobutyronitrile. An optical-grade lipophilic thermal repair resin, characterized in that it is prepared by the preparation method of an optical-grade lipophilic thermal repair resin according to any one of claims 1-8. A self-healing coating, comprising an isocyanate curing agent, characterized in that it also includes the optical-grade lipophilic heat-repairing resin as claimed in claim 9.