KR102284041B1 - Hydrophilic coating composition with excellent scratch resistance - Google Patents

Abstract

The present invention is a coating composition comprising 50 to 70% by weight of colloidal silica, 0.1 to 5% by weight of a silane coupling agent, 0.1 to 10% by weight of ethanol, 20 to 40% by weight of distilled water, and 0.001 to 5% by weight of a surfactant, wherein the silane The coupling agent relates to at least one coating composition selected from an epoxy-based silane, a compound represented by Formula 2, and an acrylic-based silane.
The present invention also provides a base film; And it relates to a coating film comprising a coating layer made of the coating composition.

Description

Hydrophilic coating composition with excellent scratch resistance {HYDROPHILIC COATING COMPOSITION WITH EXCELLENT SCRATCH RESISTANCE}

The present invention relates to a hydrophilic coating composition having scratch resistance that can be used for agricultural purposes and a coating film using the same.

As a conventional coating composition for agricultural use, a coating material mixed with a nano-inorganic colloidal sol and an acrylic resin with a glass transition temperature (Tg) adjusted was used, but this coating material had a problem in that the coating peeled off and peeled off due to scratch resistance defects. .

Patent Document 1 discloses a copolymer material 15 obtained by performing a primary copolymerization reaction of a polymerizable vinyl group component containing an active hydroxyl group and an acid group, followed by a secondary reaction between a vinyl monomer component having two or more unsaturated bonds and polyhydric alcohols. A hydrophilic resin composition containing 60 to 83% by weight of a hydrophilic polar solvent in -40% by weight, 0.01-5% by weight of a nonionic surfactant as a surfactant, and 0.01-5% by weight of a curing agent is prepared. When this composition is exposed to the outdoors for a long time, a phenomenon occurs in which it falls off from the surface of the plastic due to hardening of the surface.

Patent Document 2 discloses (A) a composite colloidal sol comprising a beaded colloidal silica sol in which spherical colloidal silica particles are connected in a beaded form and an alumina sol comprising a cluster of alumina particles having needle, granular or rod-shaped, and (B) a crosslinking agent. Disclosed is a coating composition for agriculture, characterized in that it contains, but this composition has poor scratch resistance, so that water drops on the film surface or the coating surface falls off occurs.

On the other hand, since plastic films or sheets are generally hydrophobic, when there is a high temperature and a large amount of moisture or a temperature difference between the inside and outside of the surface occurs, dew or water droplets may form on the surface of the plastic film or sheet. problems arise. In particular, agricultural films are used outdoors, and since there are crops inside, the inside of the house is created in a hot and humid environment compared to the outside.

Republic of Korea Patent No. 10-0343554 Republic of Korea Patent Registration No. 10-1522623

In order to solve the above problems, the present inventors have sought a method for maintaining long-term oil properties and maintaining weather resistance by applying a coating solution containing a hydrophilic coating composition to an agricultural film. In particular, the present invention was completed by recognizing the need for a coating agent having scratch resistance, durability, oil resistance and anti-fogging properties of the coated surface during coating by greatly improving the coating adhesion between organic and inorganic materials.

It is an object of the present invention to provide a hydrophilic coating composition having the above properties.

Another object of the present invention is to provide a method for preparing the hydrophilic coating composition.

Another object of the present invention is to provide a coating film comprising a coating layer made of the hydrophilic coating composition.

Another object of the present invention, a base film surface-modified with a surface-modifying composition; And to provide a coating film comprising a coating layer made of the hydrophilic coating composition.

In order to solve the above object, the present invention contains 50 to 70% by weight of colloidal silica, 0.1 to 5% by weight of a silane coupling agent, 0.1 to 10% by weight of ethanol, 20 to 40% by weight of distilled water, and 0.001 to 5% by weight of a surfactant As a coating composition, the silane coupling agent provides at least one coating composition selected from the group consisting of an epoxy-based silane, a compound represented by the following Chemical Formula 2, and an acryl-based silane.

In an embodiment of the present invention, the silane coupling agent may be a mixture of an epoxy-based silane, a compound represented by the following Chemical Formula 2, and an acrylic silane.

In addition, the mixture may have a weight ratio of the epoxy-based silane: the compound represented by the following Chemical Formula 2: the acryl-based silane in a weight ratio of 1:1-5:0.1-3.

In an embodiment of the present invention, the epoxy-based silane is glycidoxymethyltrimethoxysilane, 3-glycidoxypropyltrihydroxysilane, 3-glycidoxypropyldimethylhydroxysilane, 3-glycidoxypropyltri Methoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropyldimethylmethoxysilane, 3-glycidoxypropyltributoxysilane and mixtures thereof It may be selected from the group consisting of.

In an embodiment of the present invention, the compound represented by the following formula (2) is tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetra-sec-butoxy Silane, tetra-tert-butoxysilane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, Propyltriethoxysilane, isobutyltriethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane allyltri It may be selected from the group consisting of ethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and mixtures thereof.

In an embodiment of the present invention, the acrylic silane is 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyl It may be selected from the group consisting of methyldiethoxysilane, 3-acryloxypropyltrimethoxysilane, and mixtures thereof.

The present invention also comprises the steps of preparing a mixed solution by mixing colloidal silica, ethanol and distilled water; adjusting the pH of the mixed solution by adding an acid or a base; and adding a silane coupling agent to the mixed solution in an amount of 0.1 to 5% by weight based on the total weight of the mixed solution.

The present invention also provides a base film; And it provides a coating film comprising a coating layer consisting of the coating composition.

In this case, the base film may be surface-modified with a surface-modifying composition.

In an embodiment of the present invention, the surface modification composition may include polyhedral oligomeric silsesquioxane (POSS), an oxidation stabilizer, and ethylene-(meth)acrylic acid resin.

In an embodiment of the present invention, the POSS may be octaisobutyl POSS or octamethyl POSS.

In an embodiment of the present invention, the surface modification composition may further include an emulsifier.

In an embodiment of the present invention, the base film may contain the surface modification composition in the raw material composition of the base film in an amount of 5 to 20% by weight of the total weight of the composition.

In addition, the coating film of the present invention can be used for agriculture.

As an existing agricultural coating composition, the coating material prepared by mixing nano-inorganic colloidal sol and acrylic resin with adjusted glass transition temperature (Tg) had problems such as coating peeling and dropping due to scratch resistance defects. In order to solve this problem, the present inventors prepared a hydrophilic coating composition of the present invention by synthesizing an organic-inorganic synthetic composition using an inorganic colloidal silica and an organic silane compound. In addition, by developing a surface modification composition for surface modification of the base film, the corona treatment that had been performed before coating the organic substrate was excluded, and problems such as excessive pretreatment facility operation cost and industrial safety caused by the conventional corona pretreatment were solved.

The coating film formed by applying the coating composition of the present invention to a base film surface-modified with the surface modification composition exhibits excellent effects in coatability, transparency, scratch resistance, blocking resistance, low temperature hydrophilicity and high temperature hydrophilicity.

In addition, when the scratch-resistant coating composition of the present invention is coated on the surface of a plastic film or sheet, the surface strength is improved and the effect of making it hydrophilic in the long term is exhibited.

1 is a schematic view showing a coating surface into which a silane coupling agent is introduced.
2 shows a manufacturing process of a coating composition according to an embodiment of the present invention.
Figure 3 shows the contact angle of the coating film W6 according to an embodiment of the present invention.
4 shows the contact angle of the coating film W14 according to an embodiment of the present invention.
5 shows the oil state on the day and 7 days after the installation of the coating film W0 (mixed silane input amount 2.0% by weight) according to an embodiment of the present invention.
6 shows the oil state on the day and 7 days after the installation of the coating film W6 (mixed silane input amount 2.0% by weight) according to an embodiment of the present invention.
7 shows the oil state on the day and 7 days after the installation of the coating film W14 (mixed silane input amount of 2.5% by weight) according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

Although the description of the components described below may be made based on the typical embodiment of this invention, this invention is not limited to such an embodiment.

The present invention is a coating composition comprising 50 to 70% by weight of colloidal silica, 0.1 to 5% by weight of a silane coupling agent, 0.1 to 10% by weight of ethanol, 20 to 40% by weight of distilled water, and 0.001 to 5% by weight of a surfactant, wherein the silane Provided is a coating composition wherein the coupling agent is at least one selected from the group consisting of an epoxy-based silane, a compound represented by the following Chemical Formula 2, and an acryl-based silane.

The present invention relates to a method for improving the long-term hydrophilicity of a polymer film. Specifically, an organic-inorganic hybrid coating solution by a sol-gel method by reacting an inorganic colloidal silica with various types of silane coupling agents such as aminosilane, epoxysilane, acrylsilane, and a compound represented by the following formula (2) having an organic functional group. That is, the hydrophilic coating composition of the present invention with improved scratch resistance was prepared, and at this time, it was confirmed that the effect on the hydrophilicity and scratch resistance of the coating film according to the change of the type of the silane coupling agent is different, thereby completing the present invention.

In the coating composition of the present invention, alkoxysilane, which is a silane coupling agent, is used in various colloidal silica mixed solutions having particle diameters of 10 nm to 90 nm, and they function to crosslink the colloidal silica particles.

Silan coupling agent has a hydrolysis group (X) that has affinity and reactivity with inorganic materials (silica, glass, metal) and an organic functional group (Y) that chemically bonds with organic materials (organic synthetic resin) in the molecule It functions to combine organic and inorganic materials to improve mechanical strength, water resistance, and adhesion.

[Formula 1]

Silane is basically polymerized by condensation reaction with water at room temperature. In this case, the surface shows strong hydrophobicity, and the ethoxy group at one end is hydrolyzed by water to drop ethanol and become a Si-OH group. The silane is crosslinked and gelation occurs. In order to prevent such condensation and to facilitate hydrolysis, the reaction with silica must be completed by adjusting the reaction time, temperature, and pH. Then, as shown in FIG. 1, one side is bonded to the film and the other side has a coating surface with Si and OH groups. At this time, depending on how silica and silane are combined, completely different properties are exhibited even in the same composition. Transparency and adhesive strength also vary depending on reaction time, input order, and pH state. The coating film made in this way has a strong surface adhesion.

In an embodiment of the present invention, the epoxy-based silane is glycidoxymethyltrimethoxysilane, 3-glycidoxypropyltrihydroxysilane, 3-glycidoxypropyldimethylhydroxysilane, 3-glycidoxypropyl Trimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropyldimethylmethoxysilane, 3-glycidoxypropyltributoxysilane and its It may be selected from the group consisting of mixtures, but is not limited thereto. In this case, 3-glycidoxypropyltrimethoxysilane (GPTMS) or the like can be preferably used.

The silane coupling agent may preferably be a compound represented by the following formula (2).

[Formula 2]

R ¹ _x Si(OR ² ) _4-x

In Formula 2, R ¹ is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an alkenyl group having 3 to 10 carbon atoms, R ² is an alkyl group having 1 to 6 carbon atoms, and x is 0≤x<4 represents the integer of

In this case, the alkyl group may be a straight chain or a branched chain, and the number of carbon atoms is not particularly limited, but is preferably 1 to 12. Specific examples include, but are not limited to, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a pentyl group, a hexyl group, a heptyl group, and the like.

The compound represented by Formula 2 is tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert- part Toxysilane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, isobu Tyltriethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane allyltriethoxysilane, dimethyldimethoxy It may be selected from the group consisting of silane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and mixtures thereof, but is not limited thereto. In this case, methyltriethoxysilane (MTES), methyltrimethoxysilane (MTMS), vinyltriethoxysilane (VTES), etc. can be preferably used, and methyltriethoxysilane (MTES) is most preferable.

In an embodiment of the present invention, the acrylic silane is 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyl It may be selected from the group consisting of methyldiethoxysilane, 3-acryloxypropyltrimethoxysilane, and mixtures thereof. At this time, 3-acryloxypropyltrimethoxysilane (APTMS), 3-methacryloxypropyltrimethoxysilane (MPTMS), etc. can be preferably used, and -methacryloxypropyltrimethoxysilane (MPTMS) is Most preferred.

In an embodiment of the present invention, the amino-based silane may preferably be 3-aminopropyltriethoxysilane (APTES), 3-aminopropyltrimethoxysilane (APTMS), or the like, but is not limited thereto.

In addition, as other silane coupling agents, 3-isocyanatopropyltriethoxysilane (ICPTES), 3-mercaptopropyltriethoxysilane (MPTES), 3-mercaptopropyltrimethoxysilane (MPTMS), etc. are preferable. can be used

The amount of the silane coupling agent is preferably added in an amount of 0.1 to 5% by weight of the total composition weight, most preferably 2 to 3% by weight, and particularly preferably 2 to 2.5% by weight. When the amount exceeds 5% by weight, the pencil hardness and adhesion of the coating film coated with the coating composition are improved, but the hydrophilicity is greatly reduced, and when the amount is less than 0.1% by weight, the pencil hardness and adhesion are greatly reduced.

The coating composition of the present invention may contain a suitable surfactant, and may be selected from commonly used nonionic, cationic, anionic and zwitterionic surfactants, and preferably contains a nonionic surfactant in an amount of 0.001% by weight to 0.001% by weight. 5 wt% may be used, and more preferably 0.02 wt% to 0.5 wt% may be used. When out of the above range, a large amount of leakage on the film surface may cause whitening and blocking during coating.

Specifically, the surfactant is a polyhydric alcohol fatty acid ester such as sorbitan fatty acid ester, sorbitol fatty acid ester, glycerin fatty acid ester, glycerin fatty acid ester, sorbitol fatty acid dibasic acid ester, glycerin fatty acid dibasic acid ester, diglycerin fatty acid dibasic acid ester, polyhydric alcohol Fatty acid dibasic acid esters or compounds to which alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide are added. Specifically, sorbitan palmitate, sorbitol stearate, sorbitol palmitate, sorbitol stearate, diglycerin palmitate, etc. Tate, sorbitol palmitate agitate, etc. may be used, but is not limited thereto.

In an embodiment of the present invention, the silane coupling agent may be a mixture of an epoxy-based silane, an acryl-based silane, and a compound represented by Formula 2 above.

The strength of the coating surface showed a significant change when mixing an epoxy-based silane, an acryl-based silane, and a compound represented by Chemical Formula 2 in a certain ratio rather than using silane individually, and it can be seen that the scratch resistance is improved. .

In a specific embodiment of the present invention, the weight ratio of the epoxy-based silane: the compound represented by the formula (2): the acrylic silane is preferably 1:1-5:0.1-3, and more preferably 1:1-5:1 Preferably, 1:2 to 4:1 is the most preferable, and in particular, when 1:2:1 is used, it can have the most stable hydrophilicity, pencil hardness and light transmittance.

The present invention also comprises the steps of preparing a mixed solution by mixing colloidal silica, ethanol and distilled water; adjusting the pH of the mixed solution by adding an acid or a base; and adding a silane coupling agent to the acid group mixture in an amount of 0.1 to 5% by weight based on the total weight of the mixture; provides a method for producing a coating composition comprising.

One embodiment of the method for preparing the coating composition of the present invention is schematically shown in FIG. 2 of the present specification.

For the preparation of the coating composition for making the hydrophilic coating composition having excellent scratch resistance of the present invention, colloidal silica can be used as inorganic nanoparticles to exhibit hydrophilicity, and the size of the particles can be varied, for example, to be distributed in a range of 10 to 90 nm. composition can be configured. As colloidal silica, commercially available products such as Akzo Nobel can be used.

As shown in FIG. 1 , the method for preparing the hydrophilic coating composition of the present invention includes a first step of preparing a mixed solution by mixing colloidal silica, ethanol and distilled water; a second step of adjusting the pH of the mixed solution by adding an acid or a base; and a third step of adding a silane coupling agent to the mixed solution in an amount of 0.1 to 5% by weight based on the total weight of the mixed solution.

In an embodiment of the present invention, the colloidal silica, distilled water (H ₂ 0) and ethanol (EtOH, 99.5%) include colloidal silica: distilled water (H ₂ 0): ethanol is about 1 to 15:2 to 10:1 to 3 A weight ratio of 10 to 15:5 to 10:1 to 2 may be preferably used. In particular, a weight ratio of about 15:7:1.2 can be most preferably used. Thereafter, an acid or base is added to adjust the pH of the mixed solution. A desired acid or base may be added so that the pH of the mixed solution is 1 to 9, and preferably nitric acid (HN0 ₃ , 90%) or aqueous ammonia (NH ₄ OH, 28%) may be used.

Thereafter, a predetermined amount of amino silane, epoxy silane, acryl silane, a compound represented by Chemical Formula 2, and the like, which are the above-described types of silane coupling agents, is added to the solution.

The amount of the silane coupling agent may be added in an amount of 0.1 to 5% by weight of the total weight of the mixed solution, and preferably not more than 5% by weight of the total weight of the mixed solution. Most preferably, it is good to use 2-3% by weight, especially 2 to 2.5% by weight. When the amount exceeds 5% by weight, the pencil hardness and adhesion of the coating film are improved, but the hydrophilicity is greatly reduced, and when the amount is less than 0.1% by weight, the pencil hardness and adhesion are greatly reduced.

It can be manufactured by changing the amount of silane coupling agent added according to its use. When a crosslinking agent is added to a solution using acrylic silane and epoxy silane, which are silane coupling agents with carbon double bonds, self-bonding occurs over time and agglomeration occurs. It can happen, so be careful.

After stirring for 9 hours in a reaction tank maintained at 45 ° C., a dispersing agent, distilled water (H ₂ 0), and ethanol (EtOH, 99.5%) are added to stabilize the mixture to prepare a coating composition.

The present invention also provides a base film; And it provides a coating film comprising a coating layer consisting of the coating composition.

The coating film of the present invention can be obtained by coating and curing the above-described coating composition on a base film or a surface-modified base film fabric described below in the present invention.

Specifically, the coating composition prepared by the above method is used to coat the base film to a certain thickness, and the method of applying the scratch-resistant coating composition obtained in the present invention to the surface of the base film is gravure coating, dip (DEEP) coating, spray coating. method and the like. As for the adhesion amount after application|coating, 0.1-2 g/m<2> is preferable. And drying after application is possible, but natural drying is also possible, but it is preferable to dry for about 30 seconds to 60 seconds using hot air of about 50 ℃ to 90 ℃. More preferably, hot air drying is performed between 70° C. and 80° C. for about 40 seconds to 60 seconds. When the scratch-resistant coating composition of the present invention is applied to the surface of the base film, the thickness of the coating layer may be 1 µm to 30 µm, preferably 2 µm to 25 µm. If the thickness of the coating film after application is 1 μm or less, hydrophilicity is not sufficient, and if the thickness of the coating film after application is 30 μm or more, water resistance and adhesion may deteriorate and become cloudy.

After the coating is completed as described above, it can be used as a physical property test piece through a stabilization period of about 3 days.

The base film of the present invention may be surface-modified with a surface-modifying composition. Hereinafter, a surface modification composition and a film surface-modified therewith will be described.

The surface modification composition of the present invention includes polyhedral oligomeric silsesquioxane (POSS), an oxidation stabilizer, and ethylene-(meth)acrylic acid resin.

In an embodiment of the present invention, the ethylene-(meth)acrylic acid resin functions as a carrier, and includes an ethylene copolymer composed of any one monomer selected from ethylene and (meth)acrylic acid monomer, (meth)acrylate and vinyl acetate. By doing so, a more improved effect can be realized throughout the physical properties.

The ethylene copolymer is ethylene-acrylic acid (EAA) copolymer, ethylene-methacrylic acid (EMAA) copolymer, ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate (EEA) copolymer, ethylene-butylacrylic Late (EBA) copolymer and ethylene-vinyl acetate (EVA) may include any one or more selected from the group consisting of copolymers, but is not limited thereto. Preferably, it is preferable to use an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, and the use of an ethylene-methacrylic acid copolymer improves safe and sustainable adhesion to the film surface when a hydrophobic film product is present. And it is most preferable in that it is a resin having the performance to improve the adhesion of the primer/solvent to the metallized film.

In an embodiment of the present invention, the polyhedral oligomeric silsesquioxane (POSS) may be preferably octamethyl POSS or octamethyl POSS represented by the following formula (3).

Octisobutyl POSS is a hybrid molecule with inorganic silsesquioxane in the core and organic isobutyl groups attached to the cage edges, and can be used as a processing aid to improve flow during plastic processing. It can also be used to improve printability and modify the surface energy of thermoplastics.

Octamethyl POSS can be used as a plastic processing aid to improve hydrophobicity, printability and processability.

[Formula 3]

MS0825 - Octisobutyl POSS ( R= i-butyl )

MS0830 - Octamethyl POSS ( R = methyl )

In an embodiment of the present invention, the surface modification composition may further include an emulsifier.

In an embodiment of the present invention, the emulsifier is sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan sesquioleate, glyceryl laurate At least one selected from the group consisting of lactate, glyceryl stearate, glycol stearate, lecithin, polyethylene glycol-30 dipolyhydroxystearate, polyethylene glycol-4 dilaurate, and polyethylene glycol-8 dioleate. can be configured. Preferably, sorbitan monopalmitate may be used.

The surface modification composition of the present invention may be contained in the raw material composition of the base film in an amount of 5 to 20% by weight of the total weight of the composition, preferably in an amount of about 10% by weight. If it is out of the above range, there is a problem in that water resistance and scratch resistance are inferior.

As the raw material composition of the base film, high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene vinyl acetate (EVA), butene polyethylene, octene polyethylene, metallocene polyethylene, polyethylene copolymer, ionomer A resin selected from polymers, ethylene-acrylic acid (EAA), ethylene-methacrylic acid (EMAA), and mixtures thereof may be used, but is not limited thereto. Preferably linear low density polyethylene (LLDPE) and/or ethylene vinyl acetate (EVA) can be used.

The surface modification composition of the present invention may be prepared and used as a master batch (M/B). Preparation of the master batch (M/B) to be used in the surface-modified film in an embodiment of the present invention can be used by putting the surface-modified composition in a kneader, kneading it at 120° C. for 20 minutes, and then processing it in the form of pellets in an extruder. .

As a method of manufacturing the masterbatch of the surface-modified base film, it can be manufactured through the following process.

1st process: The process of injecting the raw material resin of the base film into the 1st cylinder at the processing temperature of 130-140 degreeC

Second process: The process of kneading and semi-melting the input raw material resin in the second cylinder maintained at 110~120℃

Third step: A step of side-injecting the surface modification composition of the present invention into a third cylinder and kneading with the raw resin in a semi-molten state

4th process: A process of extruding the kneaded resin at 80-90° C. and completing the final master batch (M/B) through a cutting process after forming a strand

In an embodiment of the present invention, the masterbatch is extruded into a film having a thickness of 50 to 200 μm, preferably 100 to 200 μm, more preferably about 120 μm according to a conventional film forming method, to thereby modify the surface for coating. It can be used as a base film.

The coating film of the present invention can be used for agriculture, but is not limited thereto.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is presented as a preferred example of the present invention and cannot be construed as limiting the present invention in any sense.

Example

Example 1: Preparation of coating composition

In the preparation of the coating composition for making the hydrophilic coating composition with excellent scratch resistance of the present invention, 10 to 80 nm of commercially produced colloidal silica particles of Akzo Nobel were used as inorganic nanoparticles to exhibit hydrophilicity, and the size of the particles was varied. The composition was configured to distribute evenly.

As shown in FIG. 2, the hydrophilic coating composition is first mixed in a weight ratio of colloidal silica, distilled water (H20) and ethanol (EtOH, 99.5%) 1.5:0.7:0.12 (150g: 70g: 12g), and the mixture is mixed with 1 stirred for hours.

Then, nitric acid (HN0 ₃ 90%) was added to adjust the pH of the solution to pH3, and then, 3-aminopropyltriethoxysilane (APTES), 3-glycidoxypropyltrimethoxy as a silane coupling agent to the solution. Silane (GPTMS), methacryloxypropyltrimethoxysilane (MPTMS), and methyltriethoxysilane (MTES) were added after mixing each or a predetermined ratio, and the mixture was stirred in a reactor maintained at 45° C. for 9 hours. The amount of the silane coupling agent added was changed according to its use and the experiment was carried out.

When a crosslinking agent was added to a solution using acrylsilane and epoxysilane, which are silane coupling agents with carbon double bonds, self-bonding occurred in the coating solution over time and aggregation occurred, so the final coating solution was prepared without the crosslinking agent. Using the prepared coating solution, bar-coating (No. 10) was applied to a constant thickness on a base film having a size of 40 cm × 50 cm, and cured by hot air drying (80° C.) for 1 minute to prepare a coating film.

After a stabilization period of about 3 days, the physical properties test was conducted.

The table below summarizes each example and is not limited thereto.

Example 1-1: Preparation of coating composition using epoxysilane (GPTMS)

Experimental composition S1 S2 S3 S4 S5 silica 63.48 62.98 62.48 61.98 60.98 Silane Coupling Agent 1.5 2.0 2.5 3 4.0 H ₂ O 30 30 30 30 30 Surfactants 0.02 0.02 0.02 0.02 0.02 ETOH 5 5 5 5 5

(Unit: % by weight)

Example 1-2: Preparation of coating composition using acrylsilane (MPTMS)

Experimental composition S6 S7 S8 S9 S10 silica 63.98 63.48 62.98 61.98 60.98 Silane Coupling Agent One 1.5 2.0 3.0 4.0 H ₂ O 30 30 30 30 30 Surfactants 0.02 0.02 0.02 0.02 0.02 ETOH 5 5 5 5 5

(Unit: % by weight)

Examples 1-3: Preparation of coating compositions using MTES

Experimental composition S11 S12 S13 S14 S15 silica 63.48 62.98 62.48 61.98 60.98 Silane Coupling Agent 1.5 2 2.5 3.0 4.0 H ₂ O 30 30 30 30 30 Surfactants 0.02 0.02 0.02 0.02 0.02 ETOH 5 5 5 5 5

(Unit: % by weight)

Example 1-4: Preparation of coating composition using silane mixture (GPTMS:MTES:MPTMS = 1:4:1)

Experimental composition S16 S17 S18 S19 S20 silica 63.48 62.98 62.48 61.98 60.98 Silane Coupling Agent 1.5 2 2.5 3.0 4.0 H ₂ O 30 30 30 30 30 Surfactants 0.02 0.02 0.02 0.02 0.02 ETOH 5 5 5 5 5

(Unit: % by weight)

Example 1-5: Preparation of coating composition using silane mixture (GPTMS:MTES:MPTMS = 1:2:1)

Experimental composition S21 S22 S23 S24 S25 silica 63.48 62.98 62.48 61.98 60.98 Silane Coupling Agent 1.5 2 2.5 3.0 4.0 H ₂ O 30 30 30 30 30 Surfactants 0.02 0.02 0.02 0.02 0.02 ETOH 5 5 5 5 5

(Unit: % by weight)

Example 2: Preparation of surface-modified fabric for reinforcing scratches

Example 2-1: Preparation of masterbatch (M/B) T-6 to T-7 for surface modification film preparation

The master batch (M/B) to be used for the production of the surface-modified film was put into a kneader as in the following composition, kneaded at 120° C. for 20 minutes, and then processed in the form of pellets in an extruder.

T-6 T-7 POSS[MS0825] One One Oxidation Stabilizer 0.2 0.2 EMAA1108C (DuPont) 98.8 97 SPAN40 1.8

(Unit: % by weight)

The carrier resin of M/B used DuPont's EMAA1108C.

MS0825 was used as the POSS material.

Example 2-2: Preparation of surface-modified film masterbatch (M/B) and surface-modified film

A masterbatch of U6 to U7 for surface modification film was prepared based on the reference fabric (base film) U-0 with the following composition ratio, and then the final surface-modified film was extruded to a thickness of 120 μm according to a conventional film forming method. was prepared.

U-0 2010MA 80% by weight U-6~U-7 2010MA 80% by weight BF315 20% by weight BF315 10% by weight T6~T7 10% by weight

2010MA: Linear Low Density Polyethylene (LLDPE)BF315: Ethylene Vinyl Acetate (EVA)

Surface-modified film masterbatches U-6 to U-7 were prepared by the following method.

1st process: The process of putting the raw material resin into the 1st cylinder at a processing temperature of 130-140°C

Second process: The process of kneading and semi-melting the input raw material resin in the second cylinder maintained at 110~120℃

Third step: A step of side-injecting the surface-modifying raw materials of T-6 to T-7 of the present invention into 3 cylinders and kneading them with the raw resin in a semi-molten state

4th process: The process of extruding the kneaded resin at 80-90° C. and completing the final masterbatch (M/B) of U-6 to U-7 through a cutting process after strand formation

test example

1. Evaluation method

1) Contact angle of coating film

One of the important factors for evaluating the physical properties of the hydrophilized film is the evaluation of the contact angle. Usually, hydrophilicity is expressed when the contact angle is measured to be 20 degrees or less. In order to know the degree of hydrophilicity of the coating layer, the contact angle was measured using a contact angle goniometer (Phoenix150, Surface Electro Optics). The values were read more than 10 times and the average value was taken excluding the maximum and minimum values.

2) Transmittance of the coating film

In order to measure the transmittance of the coating layer in the visible light region, the transmittance of the coating layer was measured using a HAZE meter (NDH 2000).

3) Pencil hardness of coating film

Pencil hardness was measured by inserting a pencil for measuring pencil hardness into a hardness measuring instrument (KP-M5000) at a 45 degree angle, and pushing it while applying a constant load (1 kg). Mitsubishi pencils were used as pencils, and pencils indicating the strength of H~9H, F, HB, etc. were used.

4) Adhesion of the coating film

After making a checkerboard groove on the cured coating layer with a cutter (YTC-230 cutter), the 3M tape was adhered well thereon and peeled off several times with a constant force to observe the degree of adhesion between the coating layer and the substrate. The surface of the coated support was cut in a cross shape of 11×11 at intervals of 2 mm to make 100 squares, and after attaching a tape (3M Tape) thereon, the surface was evaluated by pulling it sharply. If the number of remaining eyes was 100, 5A, 95 or more, 4A, 85 or more, 3A, 70 or more, 2A, and 50 or more, 1A.

5) Water resistance of the coating film

In order to check the water resistance of the coating film, the specimen was exposed to moisture in a thermostat maintained at 40° C. for 7 days, then taken out and dried, and the contact angle was measured using a contact angle meter (Phoenix 150, Surface Electro Optics). The values were read more than 10 times, the average values were obtained excluding the maximum and minimum values, and the water resistance of the coating film was evaluated by comparing it with the initial contact angle.

2. Results of measurement of physical properties of the coating film coated with the scratch-resistant hydrophilic coating composition of the present invention

In each of the experiments below, the scratch-resistant hydrophilic composition prepared according to Example 1 was bar-coated with a thickness of 22.8 μm on the base film fabric U0 having a size of 40 cm × 50 cm (bar-coating, No. 10) and dried with hot air for 1 minute. (80℃) to cure the coating film was prepared, and after a stabilization period of about 3 days, the physical properties were tested.

(1) Physical properties of the coating film according to the change in the amount of epoxy silane (GPTMS) added

Silane input amount (wt%) Coating solution stability initial contact angle water resistance pencil hardness adhesion light transmittance (S1) 1.5 Milky transparent/no precipitation 27.5 48.5 3B 2A 17 (S2) 2.0 “ 21.5 41.5 HB 3A 17 (S3) 2.5 “ 22.9 46.3 H 3A 16 (S4) 3.0 “ 28.1 51.6 H 3A 19 (S5) 3.5 Milky transparent / small amount of precipitation 39.3 55.3 2H 5A 18

As the amount of epoxy silane added increases, the contact angle of the coating film increases, showing a phenomenon in which hydrophilicity decreases. That is, as the amount of silane added increases, more silane is adsorbed to the surface of colloidal silica, and the number of silanol groups on the surface of colloidal silica exhibiting hydrophilicity decreases and the contact angle of the coating film increases. At 2.0 wt% to 2.5 wt% input conditions, a contact angle of 21 to 23 degrees was shown, indicating initial hydrophilicity.

The coating film was installed in a constant temperature bath at 40°C for 7 days and dried to confirm the water resistance. As a result, the water resistance was generally lowered by an increase of the contact angle of 10 to 15 or more.

The light transmittance showed no significant difference depending on the input amount.

When the amount of silane added was small, the coating film showed poor pencil hardness and adhesion, but as the input amount increased, the pencil hardness and adhesion increased. This phenomenon, when silane is added to the solution, strengthens the chemical bond between the colloidal silica and the base film, prevents cracking of the film surface during drying and curing, and improves the pencil hardness and adhesion of the coating film. Therefore, as the amount of addition increases, the chemical bond becomes stronger, and it is judged that pencil hardness and adhesion are improved compared to the case where less silane is added.

(2) Physical properties of the coating film according to the change in the amount of acrylic silane (MPTMS) added

Silane dosage (wt%) Coating solution stability initial contact angle water resistance pencil hardness adhesion light transmittance (S6) 1.0 Milky transparent/no precipitation 29.6 41.0 B 2A 16 (S7) 1.5 “ 25.9 38.5 F 3A 15 (S8) 2.0 “ 20.4 35.8 H 3A 16 (S9) 3.0 “ 32.5 45.4 H 3A 17 (S10) 4.0 Milky transparent/precipitation 40.3 54.9 2H 4A 25

When the amount of acrylic silane was increased, a phenomenon similar to that when epoxy silane was added was observed. According to the table above, it can be seen that the contact angle of the coating film shows a contact angle of 20 degrees when appropriate silane is added, indicating hydrophilicity. However, the contact angle deteriorated at the other dosages, and when it was added in excess of 3.0 wt % or more, the initial contact angle of the film was 32 degrees or more, indicating poor hydrophilicity.

In the water resistance of the coating film, the coating film was installed in a constant temperature bath at 40 ° C. for 7 days and then dried and the contact angle of the coating film was measured.

When looking at the change in transmittance in the visible light region of the coating film, the transparency of the film did not decrease even after coating and showed transmittance similar to that of the substrate. As the input amount increases to 4.0% by weight or more, the light transmittance is lower than that of the substrate due to the whitening of the coating surface.

When the input amount was small, the coating film showed poor pencil hardness and adhesion. However, as the input amount increased, the pencil hardness and adhesion increased, and in the case of 4.0% by weight, it was confirmed that the pencil hardness of 2H and the excellent adhesion of 4A were exhibited.

Overall, as the amount of the silane coupling agent added increases, the contact angle increases and the hydrophilicity decreases. Immediately after coating, hydrophilicity of about 20 degrees was shown under the condition in which a little acrylic silane was added. visibility can be verified.

In the water resistance test, it can be seen that the overall contact angle increased by 15 to 20 degrees, indicating that the water resistance was lowered.

(3) Physical properties of the coating film according to the change in the amount of MTES added

Silane dosage (wt%) Coating solution stability initial contact angle water resistance pencil hardness adhesion light transmittance (S11) 1.5 Milky transparent/no precipitation 28.8 35.7 2B 2A 15 (S12) 2.0 “ 15.7 29.4 HB 3A 14 (S13) 2.5 “ 19.0 35.2 F 3A 15 (S14) 3.0 “ 25.5 39.5 H 3A 16 (S15) 4.0 Milky transparent / no precipitation 36.1 48.9 H 4A 17

The contact angle of the coating film to which MTES was added showed an excellent contact angle of 20 degrees or less in 2.0 wt% to 2.5 wt%, and it was confirmed that the contact angle increased as the amount of the coating increased.

However, in the water resistance stage, it is judged that the hydrophilicity level is maintained similarly as the contact angle increase similar to that of the previous experiment.

The light transmittance, like other additive films, does not increase significantly compared to the fabric, and shows coating properties that improve the light transmittance at the level of the fabric or fabric.

When the amount of silane input was small, it was confirmed that the pencil hardness and adhesion were similarly decreased.

When the input amount is increased, the pencil hardness and adhesion are improved, but the contact angle of the hydrophilic film tends to increase, showing a tendency to decrease the physical properties compared to the hydrophilicity of the coating film.

(4) Physical properties of the coating film according to the amount of mixed silane added

GPTMS : MTES : MPTMS = 1:4:1 (weight ratio)

Silane dosage (wt%) Coating solution stability initial contact angle water resistance pencil hardness adhesion light transmittance (S16) 1.5 Milky transparent/no precipitation 24.3 39.7 2B 2A 16 (S17) 2.0 “ 18.7 29.4 HB 3A 14 (S18) 2.5 “ 16.4 28.2 F 3A 15 (S19) 3.0 “ 16.5 31.5 H 4A 12 (S20) 4.0 Milky transparent / no precipitation 26.1 38.9 2H 4A 14

When the amount of the mixed silane added is 2.0 to 3.0% by weight, the initial hydrophilicity is good, and the hydrophilicity decreases as the amount of the added silane increases.

That is, it is judged that the contact angle of the coating film increases as the amount of silane added increases as in the above experiment. Under the 2.5 wt% to 3.0 wt% input conditions, the initial contact angle showed a contact angle of 16 degrees, indicating good hydrophilicity.

The coating film was installed in a constant temperature bath at 40° C. for 7 days and dried to confirm the water resistance. As a result, the water resistance was generally decreased due to an increase of the contact angle of 10 or more.

The light transmittance showed no significant difference depending on the input amount.

In the case of pencil hardness and adhesion, as the amount of addition increased, the chemical bond became stronger, and the pencil hardness and adhesion were improved compared to the case where less silane was added.

(5) Physical properties of the coating film according to the amount of mixed silane added

GPTMS : MTES : MPTMS = 1:2:1 (weight ratio)

Silane dosage (wt%) Coating solution stability initial contact angle water resistance pencil hardness adhesion light transmittance (S21) 1.5 Milky transparent/no precipitation 19.8 28.7 2B 2A 15 (S22) 2.0 “ 16.7 22.4 HB 3A 14 (S23) 2.5 “ 12.3 16.3 H 4A 13 (S24) 3.0 “ 19.5 29.5 H 4A 14 (S25) 4.0 Milky transparent / no precipitation 26.1 36.9 2H 4A 17

When the mixed silane input amount was 1:2:1, the contact angle of the coating film showed an excellent contact angle of 12 to 17 degrees or less at 2.0 wt% to 2.5 wt%, and it was confirmed that the contact angle increased as the amount of the added silane increased.

In particular, it shows the most stable hydrophilicity by showing a contact angle of about 16 to 22 degrees even in the water resistance stage.

Pencil hardness and light transmittance were also found to be satisfactory levels, so a coating solution was selected to be used for the surface-modified fabric, and the coating layer was coated on the surface-modified base film fabric and then the physical properties were measured.

On the other hand, the coating solution in which amino silane was added to colloidal silica had a problem in the stability of the coating solution because gelation progressed over time.

3. Results of measurement of physical properties of the surface-modified coating film coated with the scratch-resistant hydrophilic coating composition of the present invention

In each of the experiments below, the scratch-resistant hydrophilic coating composition used in S22 and S23 was bar coated with a thickness of 22.8 μm on the base film fabric U0 or surface-modified base film fabric U-6 and U-7 having a size of 40 cm × 50 cm (bar- Coating, No. 10) and curing with hot air drying (80°C) for 1 minute to prepare a coating film, and after a stabilization period of about 3 days, the physical properties test was performed.

(1) Physical properties of the coating film coated with the coating composition of S22 on the existing film and the surface-modified film of the present invention

serial number base film
fabric Early
contact angle water resistance pencil hardness adhesion light transmittance
(before coating) light transmittance
(After coating) W0 U-0 16.7 22.4 HB 3A 11.35 14.0 W6 U-6 4.5 11.6 2H 5A 14.82 12.1 W7 U-7 9.5 12.3 H 5A 23.87 19.88

(2) Physical properties of the coating film coated with the coating composition of S23 on the existing film and the surface-modified film of the present invention

serial number base film
fabric Early
contact angle water resistance pencil hardness adhesion light transmittance
(before coating) light transmittance
(After coating) W8 U-0 12.3 16.3 H 4A 11.35 13.0 W14 U-6 4.3 9.3 2H 5A 14.82 11.10 W15 U-7 6.8 11.3 2H 5A 23.87 19.08

4. Confirmation of oil state of the surface-modified coating film coated with the scratch-resistant hydrophilic coating composition of the present invention

At the beginning of the installation of a thermostat (40℃) and after maintaining the oil state for 7 days in the constant temperature bath, the state of the oil film after drying and re-installation was observed.

(1) Oil state of manufacturing number W0: 2.0 wt% of mixed silane input

As shown in FIG. 5 , although the initial oil drop state shows a good condition, when it is reinstalled after the water resistance test, it shows a worse oil drop condition than the initial state, and the surface strength is improved but the oil drop (hydrophilicity) tends to deteriorate.

(2) Oil state of manufacturing number W6: Mixed silane input amount 2.0% by weight

As shown in FIG. 6 , when the initial thermostat is installed and reinstalled, the coating state shows good hydrophilicity, and the coating strength shows excellent values.

(3) Oil state of manufacturing number W14: 2.5 wt% of mixed silane input

As shown in FIG. 7 , it was confirmed that the film had the best water resistance among the experimental compositions and showed a similar oil state to that of the initial stage, confirming that the water resistance was excellent. It showed excellent physical properties in terms of adhesive strength and hardness, so that an agricultural coating film with excellent scratch resistance was obtained.

Claims (14)

A coating composition comprising 50 to 70% by weight of colloidal silica, 2.0 to 2.5% by weight of a silane coupling agent, 0.1 to 10% by weight of ethanol, 20 to 40% by weight of distilled water, and 0.001 to 5% by weight of a surfactant,
The silane coupling agent is a mixture of epoxy-based silane, methyltriethoxysilane and acrylic silane, and the weight ratio of the epoxy-based silane:methyltriethoxysilane:acrylic silane is 1:2:1. delete delete According to claim 1,
The epoxy-based silane is glycidoxymethyltrimethoxysilane, 3-glycidoxypropyltrihydroxysilane, 3-glycidoxypropyldimethylhydroxysilane, 3-glycidoxypropyltrimethoxysilane, 3-gly a coating selected from the group consisting of cidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropyldimethylmethoxysilane, 3-glycidoxypropyltributoxysilane and mixtures thereof composition. delete According to claim 1,
The acrylic silane is 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3- A coating composition selected from the group consisting of acryloxypropyltrimethoxysilane and mixtures thereof. preparing a mixed solution by mixing colloidal silica, ethanol and distilled water;
adjusting the pH of the mixed solution by adding an acid or a base; and
Including; adding a silane coupling agent to the mixed solution
A method for preparing the coating composition of claim 1 . base film; And a coating film comprising a coating layer consisting of the coating composition of claim 1. 9. The method of claim 8,
The base film is a coating film that is surface-modified with a surface modification composition. 10. The method of claim 9,
The surface modification composition is a coating film comprising a polyhedral oligomeric silsesquioxane (POSS), an oxidation stabilizer and ethylene (meth)acrylic acid resin. 11. The method of claim 10,
The POSS is a coating film of octaisobutyl POSS or octamethyl POSS 11. The method of claim 10,
The surface modification composition is a coating film further comprising an emulsifier. 10. The method of claim 9,
The base film is a coating film containing the surface modification composition in the raw material composition of the base film in an amount of 5 to 20% by weight of the total weight of the composition. 14. The method according to any one of claims 8 to 13,
The coating film is an agricultural coating film.

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