KR20200145239A - Hydrophilic coating composition with excellent scratch resistance - Google Patents

Abstract

The present invention relates to a hydrophilic coating composition with excellent scratch resistance, comprising: 50 to 70 wt% of colloidal silica; 0.1 to 5 wt% of a silane coupling agent; 0.1 to 10 wt% of ethanol; 20 to 40 wt% of distilled water; and 0.001 to 5 wt% of a surfactant, wherein the silane coupling agent is at least one selected from epoxy-based silanes, silane esters, and acrylic silanes, and to a coating film comprising: a base film; and a coating layer consisting 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 that has scratch resistance and can be used for agriculture and a coating film using the same.

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

Patent Document 1 is a copolymer material obtained by first copolymerizing a polymerizable vinyl group component containing an active hydroxyl group and an acid group, and secondary reaction of a vinyl monomer component having two or more unsaturated bonds thereto and a polyhydric alcohol. To prepare a hydrophilic resin composition containing 60 to 83% by weight of a hydrophilic polar solvent in -40% by weight, 0.01 to 5% by weight of a nonionic surfactant as a surfactant, and 0.01 to 5% by weight of a curing agent, When this composition is exposed to the outdoors for a long time, the hardening of the surface causes it to fall off the plastic surface.

Patent Document 2 discloses (A) a composite colloidal sol and (B) a crosslinking agent, which is composed of a beaded colloidal silica sol formed by connecting spherical colloidal silica particles in a beaded shape, and an alumina sol composed of a cluster of alumina particles having needles, granules or rods. It discloses an agricultural coating composition, characterized in that it contains, but the composition has poor scratch resistance, causing water droplets to be trapped on the film surface or dropping of the coating surface.

On the other hand, in general, plastic films or sheets are hydrophobic, so if there is a high temperature and a large amount of moisture, or if there is a temperature difference between the inside and the outside of the surface, condensation occurs on the surface of the plastic film or sheet, resulting in dew or water droplets. A problem arises. In particular, in the case of agricultural film, it is used outdoors and there are crops inside, so the inside of the house creates an environment with high temperature and humidity compared to the outside, and water droplets condense on the film surface and fall, causing cold damage to the cultivated crop.

Korean Patent Registration No. 10-0343554 Korean Patent Registration No. 10-1522623

In order to solve the above-described problem, the present inventors have sought a method capable of maintaining long-term oil droplets and 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 that a coating agent having scratch resistance, durability, oil resistance, and anti-fogging properties of the coating surface is required during coating by greatly improving the coating adhesion between organic and inorganic substances.

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 is a base film surface-modified with a surface-modifying composition; And it is 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 comprises 50 to 70% by weight of colloidal silica, 0.1 to 5% by weight of 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 surfactant As the coating composition, the silane coupling agent provides a coating composition in which at least one selected from the group consisting of epoxy-based silane, silane ester, and acrylic silane.

In an embodiment of the present invention, the silane coupling agent may be a mixture of an epoxy silane, a silane ester, and an acrylic silane.

In addition, the mixture may have a weight ratio of the epoxy-based silane: silane ester: acrylic silane of 1:1 to 5:0.1 to 3.

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

In a specific embodiment of the present invention, the silane ester compound is tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra -tert-butoxysilane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltrie Toxoxysilane, isobutyltriethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane allyltriethoxysilane , Dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and a mixture thereof may be selected from the group consisting of.

In a specific embodiment of the present invention, the acrylic silane is 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, and 3-methacryloxypropyl It may be one 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 of 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 made 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 an 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 a specific embodiment of the present invention, the base film may be one containing 5 to 20% by weight of the total weight of the surface modification composition in the raw material composition of the base film.

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

As a conventional agricultural coating composition, a coating material prepared by mixing a nano-inorganic colloidal sol and an acrylic resin adjusted to the glass transition temperature (Tg) caused problems such as coating peeling and falling off due to scratch resistance defects. In order to solve this problem, the present inventors synthesized an organic-inorganic synthetic composition using inorganic colloidal silica and an organosilane compound to prepare a hydrophilic coating composition of the present invention. In addition, by developing a surface modification composition for modifying the surface of the base film, the corona treatment that has been carried out before coating on the organic substrate has been eliminated, and problems such as excessive pretreatment facility operating costs and industrial safety due to the conventional corona pretreatment have been solved.

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

In addition, coating the scratch-resistant coating composition of the present invention on the surface of a plastic film or sheet not only improves the surface strength, but also exhibits an effect of being hydrophilic in the long term.

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

Hereinafter, the present invention will be described in detail.

The description of the constitutional requirements described below may be made based on a representative embodiment of the present invention, but the present 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, the silane It provides a coating composition in which the coupling agent is at least one selected from the group consisting of an epoxy-based silane, a silane ester, and an acrylic-based silane.

The present invention relates to a method for improving long-term hydrophilicity of a polymer film. Specifically, by reacting various types of silane coupling agents such as aminosilane, epoxy silane, acrylic silane, and silane ester having organic functional groups on colloidal silica, which is an inorganic substance, an organic-inorganic hybrid coating solution, that is, scratch resistant The hydrophilic coating composition of the present invention with improved properties was prepared, and at this time, it was confirmed that the influence on the hydrophilicity and scratch resistance of the coating film according to the change in the type of the silane coupling agent was different, thereby completing the present invention.

The coating composition of the present invention uses alkoxysilane, which is a silane coupling agent, in various colloidal silica mixtures having a particle diameter of 10 nm to 90 nm, which performs a function of crosslinking between colloidal silica particles.

Silane coupling agent has a hydrolysis group (X) having affinity and reactivity with inorganic materials (silica, glass, metal) in its molecule, and an organic functional group (Y) chemically bonding with organic materials (organic synthetic resin). It plays a role in improving mechanical strength, water resistance, and adhesion by combining organic and inorganic materials.

[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. This Si-OH group is unstable and bonds to Si-O-Si, a siloxane bond. The silane crosslinks and gelation occurs. In order to prevent such condensation and to facilitate hydrolysis, the reaction time, temperature, and pH must be adjusted to complete the reaction with silica. 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 the silica and silane are combined, completely different properties are exhibited in the same composition, but the transparency and adhesive strength are also changed according to the reaction time, the order of addition, and the pH state. The coating film made in this way has a strong surface adhesion.

In a specific 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 ester 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 linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 1 to 12. Specific examples include 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, and a heptyl group, but are not limited thereto.

The silane ester compound represented by Formula 2 is tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert -Butoxysilane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane , Isobutyltriethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane allyltriethoxysilane, dimethyl Dimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and may be selected from the group consisting of a mixture thereof, but is not limited thereto. At this time, methyltriethoxysilane (MTES), methyltrimethoxysilane (MTMS), vinyl triethoxysilane (VTES), and the like can be preferably used, and methyltriethoxysilane (MTES) is most preferred.

In a specific embodiment of the present invention, the acrylic silane is 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyl It may be one 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, 3-isocyanatopropyltriethoxysilane (ICPTES), 3-mercaptopropyltriethoxysilane (MPTES), 3-mercaptopropyltrimethoxysilane (MPTMS), and the like are preferable as other silane coupling agents. Can be used.

The amount of the silane coupling agent is preferably added in an amount of 0.1 to 5% by weight, most preferably 2 to 3% by weight, and particularly 2 to 2.5% by weight, based on the total weight of the composition. If 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. If the amount is less than 0.1% by weight, the pencil hardness and adhesion are significantly decreased.

The coating composition of the present invention may contain an appropriate surfactant, and may be selected from generally used nonionic, cationic, anionic and zwitterionic surfactants, and preferably 0.001% by weight to nonionic surfactant. 5% by weight may be used, more preferably 0.02% by weight to 0.5% by weight may be used. If it is out of the above range, a large amount of leakage may occur on the surface of the film, resulting in whitening and blocking during coating.

Specifically, the surfactant is 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, and polyhydric alcohol Fatty acid dibasic acid esters or compounds with alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide are added, and specifically sorbitan palmitate, sorbitol stearate, sorbitol palmitate, sorbitol stearate, diglycerin palmi Tate, sorbitol palmitate agitate, and the like may be used, but are not limited thereto.

In an embodiment of the present invention, the silane coupling agent may be a mixture of an epoxy-based silane, an acrylic silane, and a silane ester.

The strength of the coating surface showed a significant change when the epoxy-based silane, the acrylic-based silane, and the silane ester compound were mixed at a certain ratio rather than when individually silane was used, and scratch resistance was improved.

In a specific embodiment of the present invention, the epoxy-based silane: silane ester compound: acrylic silane has a weight ratio of 1:1 to 5:0.1 to 3, more preferably 1:1 to 5:1, and 1 :2~4:1 is the most preferable, and in particular, when 1:2:1 is used, the most stable hydrophilicity, pencil hardness, and light transmittance may be obtained.

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 acidic mixed solution in an amount of 0.1 to 5% by weight of the total weight of the mixed solution.

The method for preparing the coating composition of the present invention is schematically illustrated in FIG. 2 of the present specification.

In 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 for showing hydrophilicity, and the size of the particles can be varied, for example, to be distributed in 10 to 90 nm. Composition can be configured. As the colloidal silica, commercially available products such as Akzo Nobel can be used.

The method for preparing a hydrophilic coating composition of the present invention includes a first step of preparing a mixture by mixing colloidal silica, ethanol and distilled water, as shown in FIG. 1; 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 of 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%) are colloidal silica: distilled water (H ₂ 0): ethanol is about 1 to 15: 2 to 10: 1 to 3 It may be used by mixing so as to be a weight ratio of, and 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 may be most preferably used. Thereafter, an acid or a base is added to adjust the pH of the mixed solution. A preferred acid or base may be added so that the pH of the mixed solution is 1 to 9, and nitric acid (HN0 ₃ , 90%) or aqueous ammonia (NH ₄ OH, 28%) may be used.

Thereafter, a step of adding a certain amount of amino silane, epoxy silane, acrylic silane, silane ester, etc., which are the above types of silane coupling agents, is carried out to this solution.

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

Depending on the purpose, it can be manufactured by changing the amount of silane coupling agent input, and 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. Be careful as it may occur.

Thereafter, the mixture is stirred for 9 hours in a reaction tank maintained at 45°C, and a dispersant, distilled water (H ₂ 0), and ethanol (EtOH, 99.5%) are added to stabilize the mixture, thereby preparing a coating composition.

The present invention also provides a base film; And it provides a coating film comprising a coating layer made 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 with a certain thickness.The method of applying the scratch-resistant coating composition obtained in the present invention to the surface of the base film is gravure coating, DEEP coating, and spray coating. Method, etc. are mentioned. The amount of adhesion after application is preferably 0.1 to 2 g/m 2. The drying after application is also possible, but it is preferable to dry it for about 30 to 60 seconds using hot air of 50 to 90°C. More preferably, hot air drying is performed between 70°C and 80°C for about 40 to 60 seconds. When applying the scratch-resistant coating composition of the present invention to the surface of a 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 is less than 1 μm after application, the hydrophilicity is not sufficient, and if the thickness of the film after application is more than 30 μm, water resistance and adhesion may deteriorate and become cloudy.

When 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 thereafter.

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

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

In a specific embodiment of the present invention, the ethylene-(meth)acrylic acid resin functions as a carrier and includes an ethylene copolymer consisting of any one monomer selected from ethylene and (meth)acrylic acid monomers, (meth)acrylates and vinyl acetates. By doing so, it is possible to implement a more improved effect over the entire 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 It may include any one or more selected from the group consisting of a rate (EBA) copolymer and an ethylene-vinyl acetate (EVA) copolymer, but is not limited thereto. It is preferable to use an ethylene-acrylic acid copolymer or 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 a performance capable of improving the primer/solvent-free adhesion to the metallized film.

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

Octaisobutyl POSS is a hybrid molecule with inorganic silsesquioxane in the core and organic isobutyl groups attached to the edge of the cage 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 is a plastic processing aid that can be used to improve hydrophobicity, printability and processability.

[Formula 3]

MS0825-Octaisobutyl 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 laur. At least one selected from the group consisting of rate, 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 5 to 20% by weight of the total weight of the composition in the raw material composition of the base film, and preferably may be contained in about 10% by weight. If it is out of the above range, there is a problem that water resistance and scratch resistance are deteriorated.

The raw material composition of the base film includes 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 a polymer, ethylene-acrylic acid (EAA), ethylene-methacrylic acid (EMAA), and mixtures thereof may be used, but the present invention 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 in a master batch (M/B). In a specific embodiment of the present invention, the master batch (M/B) to be used for the surface-modified film can be prepared by putting the surface-modifying composition into a kneader, kneading at 120°C for 20 minutes, and then processing it into a pellet in an extruder. .

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

First step: a step of injecting the raw resin of the base film into the first cylinder at a processing temperature of 130 to 140°C

2nd process: A process of kneading and semi-melting the input raw material resin in a 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 it with a raw resin in a semi-melted state

4th process: the process of extruding the kneaded resin at 80~90℃, forming a strand, and cutting it to complete the final masterbatch (M/B)

In a specific embodiment of the present invention, the master batch 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 modify the surface of the coating. It can be used as a base film.

The coating film of the present invention may 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 having excellent scratch resistance of the present invention, an average particle size of 10 to 80 nm of Akzo Nobel's colloidal silica manufactured commercially was used as inorganic nanoparticles for showing hydrophilicity, and the size of the particles was varied. The composition was configured to be distributed in a way.

As shown in FIG. 2, the hydrophilic coating composition was 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 was 1 Stirred for hours.

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

When a crosslinking agent was added to a solution using acrylic silane and epoxy silane, which are silane coupling agents with a carbon double bond, self-bonding occurred in the coating solution and agglomeration occurred over time, so the final coating solution was prepared excluding the crosslinking agent. Using the prepared coating solution, bar-coating (No. 10) was performed on a base film having a size of 40 cm×50 cm to a predetermined thickness, followed by hot air drying (80° C.) for 1 minute, and cured to prepare a coating film.

Thereafter, after a stabilization period of about 3 days, the physical properties were tested.

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

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

Experiment 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: wt%)

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

Experiment 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: wt%)

Example 1-3: Preparation of coating composition using silane ester (MTES)

Experiment 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: wt%)

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

Experiment 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: wt%)

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

Experiment 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: wt%)

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

Example 2-1: Preparation of a master batch (M/B) T-6 to T-7 for manufacturing a surface-modified film

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

The carrier resin of M/B was used by 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 master batch of U6 to U7 for surface-modified films is prepared based on the standard fabric (substrate film) U-0 in the composition ratio as follows, and then extruded to a thickness of 120 μm according to a conventional film forming method to finally surface-modified film 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 master batches U-6 to U-7 were prepared by the following method.

First step: a step of introducing a raw material resin into the first cylinder at a processing temperature of 130 to 140°C

2nd process: A process of kneading and semi-melting the input raw material resin in a second cylinder maintained at 110~120℃

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

4th process: The process of extruding the kneaded resin at 80-90°C, forming a strand, and cutting it to complete the final master batch (M/B) of U-6 to U-7.

Test example

1. Evaluation method

1) Contact angle of coating film

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

2) transmittance of 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 at an angle of 45 degrees to a hardness tester (KP-M5000), and pushing it while applying a constant load (1 kg). Mitsubishi pencils were used as pencils, and pencils exhibiting strength such as H~9H, F, and HB were used.

4) adhesion of coating film

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

5) Water resistance of 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, taken out and dried, and the contact angle was measured using a contact angle goniometer (Phoenix150, Surface Electro Optics). The values were read more than 10 times to obtain an average value excluding the maximum and minimum values, and compared with the initial contact angle to evaluate the water resistance of the coating film.

2. Measurement result 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 (bar-coating, No. 10) with a thickness of 22.8 μm on the base film fabric U0 having a size of 40 cm × 50 cm, followed by hot air drying for 1 minute. This is the result of performing a physical property test after undergoing a stabilization period of about 3 days after curing by proceeding to (80°C) to prepare a coating film.

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

Silane input amount (% by weight) Coating liquid stability Initial contact angle Water resistance Pencil hardness Adhesion Transmittance (S1) 1.5 Milky, transparent/no sedimentation 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 and 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, resulting in poor hydrophilicity. That is, as the amount of silane added increases, more silane is adsorbed on the colloidal silica surface, so that the number of silanol groups on the surface of the colloidal silica exhibiting hydrophilicity decreases, thereby increasing the contact angle of the coating film. In the conditions of 2.0 wt% to 2.5 wt%, the contact angle was 21 to 23 degrees, indicating initial hydrophilicity.

The coating film was installed in a thermostat at 40°C for 7 days and then dried to check the water resistance. As a result, it was found that the water resistance was generally increased by an increase of 10-15 or more of the contact angle.

It was found that the transmittance was not significantly different depending on the input amount.

When the amount of silane added was small, the coating film showed poor pencil hardness and adhesion, but it was confirmed that the pencil hardness and adhesion increased as the input amount increased, improving to 2H and 5A respectively at 3.5% by weight. When silane is added to the solution, the chemical bond between the colloidal silica and the base film is strengthened to prevent cracking of the film surface during drying and curing, and the pencil hardness and adhesion of the coating film are improved. Therefore, it is judged that as the amount of addition increases, the chemical bond becomes stronger, and the pencil hardness and adhesion are improved compared to when less silane is added.

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

Silane input amount (% by weight) Coating liquid stability Initial contact angle Water resistance Pencil hardness Adhesion Transmittance (S6) 1.0 Milky, transparent/no sedimentation 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 and transparent / precipitation occurs 40.3 54.9 2H 4A 25

When the amount of acrylic silane was increased, a similar phenomenon was observed as when the epoxy silane was added. 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 an appropriate silane is added, indicating hydrophilicity. However, in other amounts, the contact angle deteriorated, and when the amount was added in excess of 3.0% by weight or more, the initial contact angle of the film was 32 degrees or more, indicating poor hydrophilicity.

In terms of water resistance of the coating film, when the coating film was installed in a thermostat at 40° C. for 7 days and then dried to measure the contact angle of the coating film, it was confirmed that the contact angle was increased, so that the water resistance was poor.

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

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

In general, as the amount of silane coupling agent is increased, the contact angle increases and the hydrophilicity decreases. Immediately after coating, the hydrophilicity of about 20 degrees was shown under the condition that less acrylic silane was added. However, in the case of epoxy silane, a contact angle of 21 degrees or more was achieved under all conditions. You can see it.

In the water resistance test, it can be confirmed that the water resistance is decreased by showing an increase in the contact angle of 15 to 20 degrees overall.

(3) Properties of the coating film according to the change in the amount of silane ester (MTES) added

Silane input amount (% by weight) Coating liquid stability Initial contact angle Water resistance Pencil hardness Adhesion Transmittance (S11) 1.5 Milky, transparent/no sedimentation 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 and transparent / No sedimentation 36.1 48.9 H 4A 17

The contact angle of the coating film to which the silane esters were added showed an excellent contact angle of less than 20 degrees from 2.0% to 2.5% by weight, and it was confirmed that the contact angle increased as the amount increased.

However, in the water resistance stage, it is judged that the degree of hydrophilicity remains similar, showing a similar increase in contact angle as in the previous experiment.

As with other additive films, the transmittance does not increase significantly compared to the fabric, and shows a degree of coating that improves the fabric level or fabric transmittance.

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

Increasing the input amount improved pencil hardness and adhesion, but showed a tendency to increase the contact angle of the hydrophilic film, and thus showed a tendency to decrease physical properties compared to the hydrophilicity of the coating film.

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

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

Silane input amount (% by weight) Coating liquid stability Initial contact angle Water resistance Pencil hardness Adhesion Transmittance (S16) 1.5 Milky, transparent/no sedimentation 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 and transparent / No sedimentation 26.1 38.9 2H 4A 14

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

That is, as in the above experiment, it is determined that the contact angle of the coating film increases as the amount of silane added increases. In the 2.5% to 3.0% by weight input conditions, the initial contact angle was 16 degrees, indicating good hydrophilicity.

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

It was found that the transmittance was not significantly different 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) Properties of the coating film according to the mixed silane input amount

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

Silane input amount (% by weight) Coating liquid stability Initial contact angle Water resistance Pencil hardness Adhesion Transmittance (S21) 1.5 Milky, transparent/no sedimentation 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 and transparent / No sedimentation 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 less than 12 to 17 degrees from 2.0 wt% to 2.5 wt%, and it was confirmed that the contact angle increased as the input amount 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.

The pencil hardness and light transmittance were also found to be satisfactory, so that the coating solution was selected as a coating solution to be used for the surface-modified fabric.

On the other hand, the coating solution in which amino silane was added to the colloidal silica was gelled over time, and there was a problem in the stability of the coating solution.

3. Measurement result 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 fabrics U-6 and U-7 having a size of 40 cm x 50 cm (bar- Coating, No. 10), followed by hot air drying (80°C) for 1 minute, cured to prepare a coating film, and then subjected to a stabilization period of about 3 days, and then a physical property test.

(1) 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 Transmittance
(Before coating) 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 Transmittance
(Before coating) 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. Check the oil state of the surface-modified coating film coated with the scratch-resistant hydrophilic coating composition of the present invention

The film was observed at the beginning of installation of the thermostat (40°C) and after maintaining the oil level in the thermostat for 7 days, drying, and re-installing the film.

(1) Oil state of serial number W0: 2.0% by weight of mixed silane input amount

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

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

As shown in FIG. 6, when the initial thermostat is installed and when it is reinstalled, it generally shows a coating state showing good hydrophilicity, and the coating strength shows an excellent value.

(3) Oil state of serial number W14: 2.5% by weight of mixed silane input amount

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 droplet state to that of the initial stage, thus confirming excellent water resistance. It showed excellent physical properties in terms of adhesive strength and hardness, so that an agricultural coating film having excellent scratch resistance was obtained.

Claims (14)

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,
The coating composition wherein the silane coupling agent is at least one selected from the group consisting of epoxy-based silanes, silane esters, and acrylic silanes. The method of claim 1,
The coating composition wherein the silane coupling agent is a mixture of the epoxy-based silane, silane ester, and acrylic silane. The method of claim 2,
The weight ratio of the epoxy-based silane: silane ester: acrylic silane is 1:1 to 5:0.1 to 3. The method of claim 1,
The epoxy-based silane is glycidoxymethyltrimethoxysilane, 3-glycidoxypropyltrihydroxysilane, 3-glycidoxypropyldimethylhydroxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxy Coating selected from the group consisting of cidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropyldimethylmethoxysilane, 3-glycidoxypropyltributoxysilane, and mixtures thereof Composition. The method of claim 1,
The silane ester is tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, tri Methoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, isobutyltriethoxysilane , Cyclohexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane allyltriethoxysilane, dimethyldimethoxysilane, dimethyldie A coating composition selected from the group consisting of oxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and mixtures thereof. The method of 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 in an amount of 0.1 to 5% by weight of the total weight of the mixed solution
A method for preparing the coating composition of claim 1. Base film; And a coating layer made of the coating composition of claim 1. The method of claim 8,
The base film is a coating film that is surface-modified with a surface-modifying composition. The method of claim 9,
The surface modification composition is a coating film comprising a polyhedral oligomeric silsesquioxane (POSS), an oxidation stabilizer, and an ethylene (meth)acrylic acid resin. The method of claim 10,
The POSS is a coating film of octaisobutyl POSS or octamethyl POSS The method of claim 10,
The surface modification composition is a coating film further comprising an emulsifier. The method of claim 9,
The base film is a coating film containing 5 to 20% by weight of the total weight of the surface modification composition in the raw material composition of the base film. The method according to any one of claims 8 to 13,
The coating film is an agricultural coating film.

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