CN116948441A - Coating and preparation method and application thereof - Google Patents

Abstract

The invention relates to a coating, a preparation method and application thereof, wherein the coating comprises elastic resin, acrylate monomer, curing agent and initiator; the coating does not include a solvent. The paint disclosed by the invention has adjustable viscosity, and has excellent elasticity, toughness, explosion resistance and film uniformity when a coating is formed on the surface of a CFG (middle bendable glass), small compression on the CFG, difficult breaking of the CFG during bending, excellent appearance, high light transmittance, low yellowing and haze and excellent comprehensive performance.

Description

Coating and preparation method and application thereof

Technical Field

The invention relates to the technical field of coatings, in particular to a coating and a preparation method and application thereof.

Background

With the development of display technology, various performance requirements on a screen body in a display device are gradually increased, and with the expansion of application scenes, the ultrathin glass-based flexible display panel can be applied to foldable mobile phones, notebook computers and various curled display devices.

In order to meet the bending characteristics of glass, the bending area must be thin, and there are two technological routes, namely, the whole thinning (UTG) of glass and the thinning (CFG) of only the middle part

UTG (integral bendable glass) has uniform thickness, high appearance flatness, good optical effect, simple production process and high yield of film pasting or film plating, but in order to increase the wear resistance of the coating after film plating, the surface of the coating is coated with a high-hardness wear-resistant coating (hardening liquid) with lower elongation at break, and the film plating UTG can be folded only by adopting an inward folding mode, otherwise UTG is easy to be extruded by the coating to break during outward folding.

CFG (middle bendable glass) only thin the glass bending area, the two sides of the glass are thick, the middle is thin, the whole impact resistance is better (except the middle), and the CFG is generally applied to equipment capable of simultaneously meeting inner bending and outer bending, so that the CFG has higher requirements on a film coating: the elasticity is good, and bending fogging is avoided; the elastic modulus is low, so that the CFG is prevented from being extruded during outward folding, and damage is avoided; the solid content is high, and the groove in the middle of the CFG can be filled up at one time during coating; the elongation at break is high, and meanwhile, the bending of the inner bending R1.0 and the outer bending R1.5 for 20 ten thousand times is satisfied without breaking.

CN112646504a discloses a protective cover plate and a mobile terminal, comprising a first soft adhesive layer, ultra-thin glass, a second soft adhesive layer, a polyester layer and a hardening layer which are sequentially laminated, wherein the thickness of the first soft adhesive layer is 25-50 μm; the thickness of the ultrathin glass is 50-200 mu m; the thickness of the second soft adhesive layer is 100-175 mu m; the thickness of the polyester layer is 25-50 mu m; the polyester layer is a polyethylene terephthalate film with an elastic modulus of 5000-8000 MPa; the thickness of the hardening layer is 1-7 mu m; the hardening layer is formed by irradiating ultraviolet rays to harden the hardening liquid containing organic polysilazane; and the contact angle of the pure water of the hardening layer is more than 105 degrees, and the pencil hardness is between 3H and 5H. The protective cover plate disclosed by the protective cover plate has excellent bending performance and strong surface hardness.

In view of the foregoing, it is important to develop a coating layer having excellent elasticity, toughness, explosion-proof performance and film uniformity formed on the surface of CFG.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a coating, a preparation method and application thereof, wherein the viscosity of the coating is adjustable, and the coating has excellent elasticity, toughness, explosion-proof performance and film uniformity when a coating is formed on the surface of a CFG, and has the advantages of small compression on the CFG, excellent appearance, high light transmittance, low yellowing and haze and excellent comprehensive performance.

To achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a coating comprising an elastomeric resin, an acrylate monomer, a curing agent, and an initiator;

the coating does not include a solvent.

According to the invention, the acrylic ester monomer is used as the diluent of the elastic resin, a solvent is not required to be added, the viscosity of the formed coating is adjustable, when the coating is formed on the surface of the CFG, the acrylic ester monomer is initiated by the initiator, and the elastic resin is cured by the curing agent, so that the coating has the advantages of excellent elasticity, toughness, explosion-proof performance and film uniformity, small compression on the CFG, excellent appearance, high light transmittance, low yellowing and haze and excellent comprehensive performance.

If elastic resin is used alone to prepare the flexible coating, the following disadvantages are encountered: the low-modulus elastic resin has high viscosity and is difficult to coat; under the condition of no solvent, the elastic resin is easy to foam after the isocyanate curing agent is added, and the operation time is short and the gel is quick; if solvent is added, the wet film of the coating at the groove position is thicker, the liquid level at the groove position is reduced after the solvent is dried, so that the CFG groove of the coating is difficult to fill, the coating surface can be filled only by coating for multiple times, the process is more complex, and the yield is reduced.

If the flexible ultraviolet curing coating is adopted singly to prepare the flexible coating for CFG, the following defects are caused: the ultraviolet light curing elastic coating generally adopts difunctional and monofunctional UV resin or monomer, has low curing speed and incomplete curing, has strong flexibility but insufficient elasticity, can deform after bending in one direction for a long time, is difficult to recover, has weak scratch resistance and is easy to scratch and generate bad.

Preferably, the elastomeric resin comprises any one or a combination of at least two of a hydroxyl-terminated aliphatic polyester resin, a hydroxyl-terminated aliphatic polyurethane resin, or a hydroxyl acrylic resin, wherein typical but non-limiting combinations include: a combination of a hydroxyl-terminated aliphatic polyester resin and a hydroxyl-terminated aliphatic polyurethane resin, a combination of a hydroxyl-terminated aliphatic polyurethane resin and a hydroxyl acrylic resin, a combination of a hydroxyl-terminated aliphatic polyester resin, a hydroxyl-terminated aliphatic polyurethane resin and a hydroxyl acrylic resin, and the like.

Preferably, the acrylate monomers include monofunctional acrylate monomers and/or difunctional acrylate monomers, more preferably mono-tube-energy acrylate monomers.

In the invention, the reason that the acrylate monomer is further preferable to the single-tube-energy acrylate is that the single-functionality acrylate has smaller molecular weight, better dilution effect and only one crosslinking group, so that the formed coating has better flexibility and is not hard.

Preferably, the monofunctional acrylate monomers comprise acryloylmorpholine and/or ethoxylated phenyl acrylate.

Preferably, the difunctional acrylate monomer comprises polypropylene glycol diacrylate and/or tripropylene glycol diacrylate.

Preferably, the difunctional acrylate monomer has a number average molecular weight of greater than or equal to 200g/mol, for example 300g/mol, 400g/mol, 600g/mol, 800g/mol, 1000g/mol, 2000g/mol, etc.

In the invention, the number average molecular weight of the difunctional acrylate monomer is more than 200g/mol, because the difunctional acrylate monomer has two reactive groups, if the molecular weight is too small, the content of the reactive groups of the acrylate is too high, and the formed product has larger crosslinking degree and insufficient toughness.

Preferably, the curing agent comprises any one or a combination of at least two of hexamethylene diisocyanate trimer, hexamethylene diisocyanate biuret, or isophorone diisocyanate trimer, wherein typical but non-limiting combinations include: combinations of hexamethylene diisocyanate trimer and hexamethylene diisocyanate biuret, combinations of hexamethylene diisocyanate biuret and isophorone diisocyanate trimer, and the like.

Preferably, the initiator comprises any one or a combination of at least two of 1-hydroxycyclohexyl phenyl ketone, ethyl 2,4, 6-trimethylbenzoyl phenyl phosphonate or 2-hydroxy-2-methyl-1-phenyl-1-propanone, wherein typical but non-limiting combinations include: a combination of 1-hydroxycyclohexylphenyl ketone and ethyl 2,4, 6-trimethylbenzoylphenyl phosphonate, a combination of ethyl 2,4, 6-trimethylbenzoylphenyl phosphonate and 2-hydroxy-2-methyl-1-phenyl-1-propanone, a combination of 1-hydroxycyclohexylphenyl ketone, ethyl 2,4, 6-trimethylbenzoylphenyl phosphonate and 2-hydroxy-2-methyl-1-phenyl-1-propanone, and the like.

Preferably, the coating comprises the following components in parts by weight:

in the invention, the elastic resin and the acrylic ester monomer are matched for use in a specific proportion, and excessive addition of the elastic resin can cause excessive viscosity of the coating, is difficult to coat and gel, and has short operable time; the addition amount of the elastic resin is too low, so that the coating has insufficient elasticity and is easy to fog after being bent for many times; the excessive addition of the acrylic ester monomer can lead to the coating having better flexibility but insufficient elasticity; the addition amount of the acrylic ester monomer is too low, which can cause excessive viscosity of the coating, short operation time and easy gelation.

In the present invention, the weight part of the elastic resin is 40 to 80 parts, for example 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, etc.

The acrylate monomer is 20-60 parts by weight, for example 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, etc.

The curing agent is 5-30 parts by weight, for example 10 parts, 15 parts, 20 parts, 25 parts, etc.

The initiator is 1 to 5 parts by weight, for example 2 parts, 3 parts, 4 parts, etc.

Preferably, the coating further comprises an auxiliary agent.

Preferably, the auxiliary agent comprises a leveling agent and/or a drier.

Preferably, the leveling agent comprises a silicone leveling agent.

Preferably, the drier comprises an organotin drier.

Preferably, the leveling agent is 0.1 to 1 part by weight, for example, 0.2 part, 0.4 part, 0.6 part, 0.8 part, 1.0 part, etc.

Preferably, the drier is present in an amount of 0 to 0.1 parts by weight, for example 0.01 parts, 0.02 parts, 0.04 parts, 0.06 parts, 0.08 parts, etc.

In a second aspect, the present invention provides a method for preparing the coating according to the first aspect, the method comprising the steps of:

under the yellow light environment, an initiator is dissolved in an acrylic ester monomer, and then is sequentially mixed with an elastic resin and a curing agent for defoaming, so that the coating is obtained.

Preferably, the preparation method further comprises dissolving an auxiliary agent in the acrylate monomer.

In a third aspect, the present invention provides a coating formed from the coating of the first aspect.

In a fourth aspect, the present invention provides a method for preparing the coating according to the second aspect, the method comprising the steps of:

and (3) coating the coating in the first aspect on the surface of a substrate, and performing heat curing and photo curing to obtain the coating.

In a fifth aspect, the present invention provides a middle bendable glass coating assembly, the surface of which is provided with a coating according to the third aspect.

In a sixth aspect, the present invention provides a method for preparing the middle bendable glass coating assembly according to the fifth aspect, the method comprising the following steps:

(1) The middle bendable glass is firstly treated by a coupling agent, and then a glass primer with the thickness of 3-5 mu m (such as 3.5 mu m, 4 mu m, 4.5 mu m and the like) is coated;

(2) And (3) coating the paint in the first aspect on the surface of the primer of the middle bendable glass, and performing heat curing and photo curing to obtain the middle bendable glass coating component.

Compared with the prior art, the invention has the following beneficial effects:

(1) The viscosity of the paint is controllable, and the paint has good leveling property;

(2) When the coating forms a coating on the surface of the CFG, the coating has good film thickness uniformity because of being a solvent-free coating, and the coating has almost no shrinkage in volume when being solidified, so that the coating can uniformly fill the middle groove of the CFG; the adhesive force with the primer is good, and the adhesive force is expressed as that the percentage of the primer before and after water boiling is 5B; the elasticity is good, the repairing is realized by slight scratch, and the CFG can be restored after being placed for 12 hours at normal temperature after R1.0 is bent for 20 ten thousand times; the compression on CFG is small, and the R1.0 inward fold and the R1.5 outward fold are not broken for more than 20 ten thousand times; the explosion-proof performance is good, and the CFG can be completely adhered to the coating after being broken; the appearance is excellent, the light transmittance is more than 91%, the haze is less than 0.5%, and the yellowness is less than 0.5%.

Detailed Description

The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.

The purchase information of partial raw materials in each embodiment of the invention is as follows:

hydroxyl-terminated aliphatic polyester resin: purchased from Dongguan left melt industry with the brand of 175-100;

HDI trimer curing agent: purchased from kesi, trade mark 3390;

organosilicon leveling agent: purchased from pick chemical under the brand BYK333;

organotin drier: dibutyl tin dilaurate;

polypropylene glycol (700) diacrylate: purchased from Changxing chemical under the trademark EM2208;

ethoxylated phenyl acrylate: purchased from Changxing chemical under the trademark EM210;

acryloylmorpholine; purchase from Xinghuang chemistry;

aromatic saturated polyester resin: purchased from SK company under the brand ES-812;

UV aliphatic urethane acrylate: purchased from changxing chemical, trade name 3113.

Example 1

The embodiment provides a solvent-free coating, which consists of the following components:

a first component: 30g of ethoxylated phenyl acrylate, 67.8g of hydroxyl-terminated aliphatic polyester resin, 1g of 1-hydroxycyclohexyl phenyl ketone, 1.2g of ethyl 2,4, 6-trimethylbenzoyl phenylphosphonate, 0.5g of organosilicon leveling agent and 0.01g of organotin drier;

and a second component: HDI trimer curing agents.

The solvent-free paint is prepared by a method comprising the steps of:

under a yellow light environment, adding 1-hydroxy cyclohexyl phenyl ketone and 2,4, 6-trimethyl benzoyl phenyl phosphonic acid ethyl ester into phenyl acrylate oxide, stirring until the phenyl ketone and the 2,4, 6-trimethyl benzoyl phenyl phosphonic acid ethyl ester are completely dissolved, then adding an organosilicon leveling agent and an organotin drier, continuously stirring for 5 minutes, finally adding hydroxyl-terminated aliphatic polyester resin, and uniformly stirring to obtain a first component. The composition comprises the following components in use: second component = 5: and 1, adding a second component, stirring uniformly, and removing bubbles in vacuum to obtain the coating.

Example 2

The embodiment provides a solvent-free coating, which consists of the following components:

a first component: 50g of ethoxylated phenyl acrylate, 47g of hydroxyl-terminated aliphatic polyester resin, 1.5g of 1-hydroxycyclohexyl phenyl ketone, 1.5g of ethyl 2,4, 6-trimethylbenzoyl phenylphosphonate, 0.5g of organosilicon leveling agent and 0.01g of organotin drier;

and a second component: HDI trimer curing agents.

The solvent-free paint is prepared by a method comprising the steps of:

under a yellow light environment, adding 1-hydroxy cyclohexyl phenyl ketone and 2,4, 6-trimethyl benzoyl phenyl phosphonic acid ethyl ester into ethoxylated phenyl acrylate, stirring until the mixture is completely dissolved, then adding an organosilicon leveling agent and an organotin drier, continuously stirring for 5 minutes, finally adding hydroxyl-terminated polyester resin, and uniformly stirring to obtain a first component. The composition comprises the following components in use: second component = 7: and 1, adding a second component, stirring uniformly, and removing bubbles in vacuum to obtain the coating.

Example 3

This example differs from example 1 in that the ethoxylated phenyl acrylate is replaced by an equal mass of acryloylmorpholine, the remainder being the same as example 1.

Example 4

This example differs from example 1 in that the ethoxylated phenyl acrylate was replaced with an equal mass of polypropylene glycol (700) diacrylate, the remainder being the same as example 1.

Comparative example 1

This comparative example differs from example 1 in that the hydroxy-terminated aliphatic elastomeric resin was replaced with an equal mass of aromatic saturated polyester resin while the ratio of the first component to the HDI trimer was changed to 20:1, the remainder being the same as in example 1.

Comparative example 2

The comparative example differs from example 1 in that the hydroxyl-terminated aliphatic elastomeric resin was replaced with an equal mass of UV urethane acrylate, which was cured only with UV, the formulation being specifically proportioned as follows:

30g of ethoxylated phenyl acrylate, 66g of UV polyurethane acrylate, 2g of 1-hydroxycyclohexyl phenyl ketone, 2g of ethyl 2,4, 6-trimethylbenzoyl phenyl phosphonate and 0.5g of organosilicon leveling agent.

Comparative example 3

This comparative example differs from example 1 in that the acrylate monomer was replaced with an equal mass of methyl isobutyl ketone solvent and the initiator 1-hydroxycyclohexyl phenyl ketone and ethyl 2,4, 6-trimethylbenzoyl phenyl phosphonate were removed, the remainder being the same as in example 1.

Comparative example 4

This comparative example differs from example 1 in that the ethoxylated phenyl acrylate was replaced with equal mass of trimethylolpropane triacrylate, the remainder being the same as example 1.

Performance testing

The coatings described in examples 1-4 and comparative examples 1-4 were tested as follows:

(1) Viscosity of the coating: a rotary viscometer is adopted;

(2) Leveling property: observing shrinkage holes, orange peel, pits, scraping marks and the like on the surface of the coated coating:

the coatings described in examples 1-4 and comparative examples 1-4 were formed into coatings and tested as follows:

(1) Preparation of the coating: the method comprises the steps of cleaning the surface of the middle bendable glass, then carrying out coupling agent treatment (siloxane coupling agent), then coating a primer (purchased from Fangfu Fule new material with the brand of 1955A, adopting an HDI trimer as a curing agent and the thickness of 3-5 mu m), drying at 100 ℃ for 30min, then coating the coating on the surface of the primer layer, and carrying out heat curing and photo curing to form a coating (with the thickness of 30-60 mu m), thus obtaining the middle bendable glass component.

(2) Fillability: testing the thickness difference between the position of the CFG groove and the position beside the CFG groove after coating;

(3) Hundred grid test: according to national standard test, the boiling condition is 95 ℃ multiplied by 1h;

(4) Transmittance/haze/yellowness: a spectroscopic tester;

(5) Elasticity: after 20 ten thousand times of inward folding, the coated CFG is horizontally placed on a table top, the time required by the CFG to restore to be flat is recorded, and the shorter the time is, the better the elasticity is;

(6) Bending property: and carrying out R1.0 inward folding and R1.5 outward folding on the coated CFG by adopting a book-turning type bending machine.

The test results are summarized in table 1 below.

TABLE 1

Analysis of the data in Table 1 shows that the viscosity of the coating disclosed by the invention is controllable, and the coating has good leveling property; when the coating forms a coating on the surface of the CFG, the coating has good film thickness uniformity and groove filling property, and the coating has almost no shrinkage in volume when being solidified, so that the groove in the middle of the CFG can be uniformly filled; the adhesive force to the primer is good, and the adhesive force is expressed as that the percentage of the primer can reach 5B before and after boiling; the elasticity is good, the repairing is realized by slight scratch, and the CFG can be restored after being placed for 12 hours at normal temperature after R1.0 is bent for 20 ten thousand times; the compression on CFG is small, and the CFG is not broken and cracked after being folded for more than 20 ten thousand times in R1.0 and R1.5; the explosion-proof performance is good, and the CFG can be completely adhered to the coating after being broken; the appearance is excellent, the light transmittance is more than 91%, the haze is less than 0.5%, and the yellowness is less than 0.5%.

Analysis of example 2 and example 1 shows that example 2 does not perform as well as example 1, demonstrating that coating viscosity is too low to facilitate filling of CFG grooves with the coating.

As can be seen from the analysis of comparative example 1 and example 1, the performance of comparative example 1 is inferior to that of example 1, and it is proved that the aromatic saturated polyester resin has a higher viscosity, a lower elasticity and a higher hardness than the aliphatic polyester elastic resin, and is liable to cause CFG breakage and is not suitable for the system.

As can be seen from the analysis of comparative example 2 and example 1, comparative example 2 has inferior performance to example 1, and it is proved that the UV urethane acrylate resin as an elastic resin has weaker elasticity than the thermosetting elastic resin, is not easily restored to its original shape after 20 times of bending, and is easily fogged in the bending region.

Analysis of comparative example 3 and example 1 shows that comparative example 3 does not perform as well as example 1, demonstrating that the coating cannot fill the central groove region of the CFG in the presence of solvent.

As can be seen from analysis of comparative example 4 and example 1, comparative example 4 has inferior performance to example 1, and it is proved that after the acrylic ester monomer is lifted from mono-functional to tri-functional, the crosslinking degree of the coating is greatly improved, the elastic modulus is increased, the adhesive force is reduced, and the CFG is easily crushed by extrusion during outward folding.

The applicant states that the detailed method of the present invention is illustrated by the above examples, but the present invention is not limited to the detailed method described above, i.e. it does not mean that the present invention must be practiced in dependence upon the detailed method described above. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of raw materials for the product of the present invention, addition of auxiliary components, selection of specific modes, etc., falls within the scope of the present invention and the scope of disclosure.

Claims (10)

1. A coating, characterized in that the coating comprises an elastic resin, an acrylate monomer, a curing agent and an initiator;

the coating does not include a solvent.

2. The coating of claim 1, wherein the elastomeric resin comprises any one or a combination of at least two of a hydroxyl-terminated aliphatic polyester resin, a hydroxyl-terminated aliphatic polyurethane resin, or a hydroxyl acrylic resin.

3. The coating according to claim 1 or 2, wherein the acrylate monomer comprises a monofunctional acrylate and/or a difunctional acrylate;

preferably, the monofunctional acrylate monomers comprise acryloylmorpholine and/or ethoxylated phenyl acrylate;

preferably, the difunctional acrylate monomer comprises polypropylene glycol diacrylate and/or tripropylene glycol diacrylate;

preferably, the number average molecular weight of the difunctional acrylate monomer is more than or equal to 200g/mol.

4. A coating according to any one of claims 1 to 3, wherein the curing agent comprises any one or a combination of at least two of hexamethylene diisocyanate trimer, hexamethylene diisocyanate biuret or isophorone diisocyanate trimer;

preferably, the initiator comprises any one or a combination of at least two of 1-hydroxycyclohexyl phenyl ketone, ethyl 2,4, 6-trimethylbenzoyl phenyl phosphonate or 2-hydroxy-2-methyl-1-phenyl-1-propanone.

5. The coating according to any one of claims 1-4, wherein the coating comprises the following components in parts by weight:

preferably, the coating further comprises an auxiliary agent;

preferably, the auxiliary agent comprises a leveling agent and/or a drier;

preferably, the leveling agent comprises a silicone leveling agent;

preferably, the drier comprises an organotin drier;

preferably, the weight part of the leveling agent is 0.1-1 part;

preferably, the weight part of the drier is 0-0.1 part.

6. A method of preparing the coating of any one of claims 1-5, comprising the steps of:

under a yellow light environment, dissolving an initiator in an acrylic ester monomer, and then sequentially mixing with an elastic resin and a curing agent for defoaming to obtain the coating;

preferably, the preparation method further comprises dissolving an auxiliary agent in the acrylate monomer.

7. A coating, characterized in that the coating is formed from the coating according to any one of claims 1-5.

8. A method of preparing the coating of claim 7, comprising the steps of:

coating the coating according to any one of claims 1-5 on the surface of a substrate, and performing heat curing and photo curing to obtain the coating.

9. A mid-bendable glass coating assembly, wherein the substrate surface of the mid-bendable glass coating assembly is provided with the coating of claim 7.

10. A method of making a mid-bendable glass coating assembly according to claim 9, comprising the steps of:

(1) Firstly, treating the middle bendable glass with a coupling agent, and then coating a layer of glass primer with the thickness of 3-5 mu m;

(2) Coating the paint of any one of claims 1-5 on the surface of the primer of the middle bendable glass, and performing heat curing and photo curing to obtain the middle bendable glass coating assembly.