KR102563668B1 - Boundary stone attachment cover with excellent retro-reflective properties, and manufacturing method thereof - Google Patents

Abstract

The present invention is a polylactic acid-containing base layer; It is formed on the base layer and includes glass beads surface-modified with a fluorine-containing silane-based compound and a polymer binder, wherein the glass beads surface-modified with the fluorine-containing silane-based compound are embedded in the polymer binder in a structure in which they protrude to the outside. reflective layer; and a transparent protective layer formed on the reflective layer and having a curved structure corresponding to the glass beads surface-modified with a fluorine-containing silane-based compound.

Description

Boundary stone attachment cover with excellent retro-reflective properties, and manufacturing method thereof}

The present invention relates to a cover for attaching a boundary stone having excellent retroreflective properties and a manufacturing method thereof.

Changes in the global environment are leading to changes in megatrends in the material market. In particular, the problem of global warming is a worldwide problem, and it can be seen that the temperature of the earth has been steadily increasing for a long time. Humanity recognizes that such an increase in global temperature is due to an increase in the amount of carbon dioxide generated along with industrial development. Therefore, there is a movement to convert petroleum-based chemical materials that have been used so far to biomass-based materials that reduce carbon dioxide. Another factor contributing to the change in material market megatrends is rising oil prices and depletion of crude oil. Since the amount of crude oil existing on earth is constant, continued use causes depletion of petroleum resources. One of the most necessary ways to solve the problem of global warming and petroleum resources is to utilize biomass, a sustainable resource.

Currently, the most representative bioplastic in the market is polylactic acid (PLA), which is a highly biodegradable aliphatic polyester. Polylactic acid has a melting point of about 175 ° C, which is sufficiently higher than other aliphatic polyesters, is relatively transparent, and has excellent mechanical properties. In addition, since lactic acid as a raw material is obtained from renewable resources such as plants, there is a sustainability of supply of the material, and it is greatly expected in that it does not use depleted resources such as petroleum.

However, polylactic acid has disadvantages such as low elongation and weak impact resistance, and thus compatibility is remarkably deteriorated, and improvement thereof is required.

On the other hand, retro-reflective is a reflection in which light from a light source is reflected from the surface of an object and returns to the light source, and it is characterized by reflection in the direction of the light source even when light is shined on a retroreflective material at any angle. .

Due to this feature, when the light from the headlights of a car shines on the retroreflective material, the light returns to the direction in which the light shines, that is, the direction of the headlights, thereby increasing the driver's visibility at night, thereby preventing traffic accidents very effectively. There are advantages to being able to do it.

A commonly used boundary stone serves as a landmark and safety means to divide roads and sidewalks, or to separate parks, flower beds, architectural complexes such as apartment complexes, children's playgrounds, and bicycle paths. It is arranged in the shape of a rectangular parallelepiped with a length of about m.

The present inventors completed the present invention after repeated research to develop a cover for attaching boundary stones that has excellent physical properties such as retroreflective properties, processing properties, shrinkage properties, and elastic recovery rate, while having excellent environmental friendliness by utilizing polylactic acid, a representative bioplastic. I came to do it.

As a similar prior literature for this, Korean Patent Publication No. 10-2018-0083693 is presented.

Republic of Korea Patent Publication No. 10-2018-0083693 (200818.07.23)

In order to solve the above problems, the present invention utilizes polylactic acid to provide a boundary stone attachment cover that is environmentally friendly and has excellent physical properties such as retroreflective properties, processing properties, shrinkage properties, and elastic recovery rate, and a manufacturing method thereof aims to

One aspect of the present invention for achieving the above object is a polylactic acid-containing base layer; It is formed on the base layer and includes glass beads surface-modified with a fluorine-containing silane-based compound and a polymer binder, wherein the glass beads surface-modified with the fluorine-containing silane-based compound are embedded in the polymer binder in a structure in which they protrude to the outside. reflective layer; and a transparent protective layer formed on the reflective layer and having a curved structure corresponding to the glass beads surface-modified with a fluorine-containing silane-based compound.

In the above aspect, the fluorine-containing silane-based compound may satisfy Formula 1 below.

[Formula 1]

(In Formula 1, R ₁ to R ₃ are each independently an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, but at least one or more of R ₁ to R ₃ is an alkoxy group; X is 1 to 6 carbon atoms 12 fluoroalkyl group; n is an integer from 1 to 10.)

In the above aspect, the surface-modified glass beads with the fluorine-containing silane-based compound may be pretreated with a basic solution before being surface-modified with the fluorine-containing silane-based compound, wherein the basic solution is an aqueous solution of sodium hydroxide or potassium hydroxide It may be any one or a mixture of two or more selected from the group consisting of an aqueous solution and calcium hydroxide.

In the above embodiment, the base layer may include 5 to 10 parts by weight of polypropylene, 20 to 50 parts by weight of silica surface-modified with an epoxy group, and 2 to 5 parts by weight of an emulsifier based on 100 parts by weight of polylactic acid.

In one aspect, the weight average molecular weight of the polylactic acid may be 10,000 to 20,000 g/mol.

In the above aspect, the polypropylene may have a weight average molecular weight of 300,000 to 1,000,000 g/mol.

In the above aspect, the surface-modified silica with an epoxy group may be a surface of silica particles coated with a silane-based compound containing an epoxy group, and more specifically, the silane-based compound containing an epoxy group is 2-(3 In the group consisting of ,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane and 3-glycidoxypropyltriethoxysilane, etc. It may be any one selected or a mixture of two or more.

In the above aspect, the emulsifier is selected from the group consisting of diethylene glycol monostearate, propylene glycol monostearate, glyceryl monostearate, glyceryl monolinoleate, glyceryl monooleate and glyceryl monopalmitate It may be any one or a mixture of two or more.

In the above aspect, the polymeric binder may be a silicon-based binder having a weight average molecular weight of 3,000 to 300,000 g/mol.

In the above aspect, the transparent protective layer may be prepared by UV-curing a protective layer composition including an acrylate-based oligomer, an acrylate-based monomer, and a photoinitiator.

In addition, another aspect of the present invention is a) molding a base composition comprising 5 to 10 parts by weight of polypropylene, 20 to 50 parts by weight of silica surface-modified with an epoxy group, and 2 to 5 parts by weight of an emulsifier based on 100 parts by weight of polylactic acid to form a base layer; b) forming a reflective layer by applying a polymeric binder on the base layer and burying a portion of glass beads surface-modified with a fluorine-containing silane-based compound on top of the polymeric binder so as to protrude; and c) forming a transparent protective layer on the reflective layer.

The cover for attaching boundary stone according to the present invention can provide an environmentally friendly product by using polylactic acid, which is a biodegradable polymer, as a base resin. Accordingly, there is an additional effect that it can have strength against various environmental regulations and can significantly reduce subsequent processing costs.

In addition, by mixing polypropylene and silica with the polylactic acid, physical properties such as processing characteristics, shrinkage characteristics, and elastic recovery rate can be improved. Due to the increased resistance, the cover for attaching the boundary stone may not be easily damaged even in shock and severe temperature change.

In addition, the cover for attaching boundary stones according to the present invention may have excellent retroreflective properties by forming a reflective layer including glass beads surface-modified with a fluorine-containing silane-based compound on the base layer. In particular, by surface-modifying the glass beads with a fluorine-containing silane-based compound, adhesion to the polymer binder is improved, and thus glass beads can be prevented from being detached from the polymer binder even after long-term use, and thus the retroreflective properties are deteriorated even after long-term use. It has the advantage of being continuously maintained.

1 is an exemplary structural diagram of a cover for attaching a boundary stone according to an embodiment of the present invention.

Hereinafter, a cover for attaching a boundary stone and a manufacturing method thereof according to the present invention will be described in detail. The drawings introduced below are provided as examples so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art. Therefore, the present invention may be embodied in other forms without being limited to the drawings presented below, and the drawings presented below may be exaggerated to clarify the spirit of the present invention. At this time, unless there is another definition in the technical terms and scientific terms used, they have meanings commonly understood by those of ordinary skill in the art to which this invention belongs, and the gist of the present invention in the following description and accompanying drawings Descriptions of well-known functions and configurations that may be unnecessarily obscure are omitted.

One aspect of the present invention is a polylactic acid-containing base layer; It is formed on the base layer and includes glass beads surface-modified with a fluorine-containing silane-based compound and a polymer binder, wherein the glass beads surface-modified with the fluorine-containing silane-based compound are embedded in the polymer binder in a structure in which they protrude to the outside. reflective layer; and a transparent protective layer formed on the reflective layer and having a curved structure corresponding to the glass beads surface-modified with a fluorine-containing silane-based compound.

As such, an environmentally friendly product can be provided by using polylactic acid, which is a biodegradable polymer, as a base resin. Accordingly, there is an additional effect that it can have strength against various environmental regulations and can significantly reduce subsequent processing costs.

In addition, by mixing polypropylene and silica with the polylactic acid, physical properties such as processing characteristics, shrinkage characteristics, and elastic recovery rate can be improved. Due to the increased resistance, the cover for attaching the boundary stone may not be easily damaged even in shock and severe temperature change.

In addition, the cover for attaching boundary stones according to the present invention may have excellent retroreflective properties by forming a reflective layer including glass beads surface-modified with a fluorine-containing silane-based compound on the base layer. In particular, by surface-modifying the glass beads with a fluorine-containing silane-based compound, adhesion to the polymer binder is improved, and thus glass beads can be prevented from being detached from the polymer binder even after long-term use, and thus the retroreflective properties are deteriorated even after long-term use. It has the advantage of being continuously maintained.

Hereinafter, each component of the boundary stone attachment cover according to the present invention will be described in detail.

First, the base layer according to the present invention may include 5 to 10 parts by weight of polypropylene, 20 to 50 parts by weight of silica surface-modified with an epoxy group, and 2 to 5 parts by weight of an emulsifier based on 100 parts by weight of polylactic acid.

In one embodiment of the present invention, the polylactic acid (PLA, poly(lactic acid)) is an aliphatic polyester synthesized by polycondensation of lactic acid or ring-opening polymerization of lactide. It may be prepared using a natural vegetable sugar component obtained from corn as a raw material, for example, poly-L-lactide (PLLA), poly-D-lactide (PDLA) and poly-LD-lactide (PDLLA). It may be any one or a mixture of two or more selected from the group consisting of.

More specifically, polylactic acid suitable for use in the present invention may be low molecular weight polylactic acid, and as a specific example, the weight average molecular weight of polylactic acid may be 10,000 to 20,000 g/mol. It has excellent biodegradability within this range and may have compatibility.

Such polylactic acid has high biodegradability, but generally has high hardness, low elasticity, and low durability. Therefore, it is appropriately mixed with other components to increase physical properties such as processing characteristics, shrinkage characteristics, and elastic recovery rate. It is desirable to maintain biodegradable properties while doing so.

In one example of the present invention, the polypropylene is a general-purpose polymer having excellent molding processability and chemical resistance, excellent mechanical properties such as tensile strength and flexural strength, and excellent thermal properties such as thermal expansion coefficient and high heat deflection temperature. , It is advantageous in that it is easy to produce a product by blending with polylactic acid, and the processing characteristics of the base layer can be improved. In addition, while maintaining the biodegradable characteristics of polylactic acid, there is an advantage in that it is possible to secure a cover for attaching a boundary stone with improved shrinkage characteristics, elastic recovery rate, strength and thermal characteristics.

More specifically, the weight average molecular weight of polypropylene suitable for use in the present invention may be 300,000 to 1,000,000 g/mol, and the amount added may be 5 to 10 parts by weight based on 100 parts by weight of polylactic acid. In this range, miscibility with polylactic acid is more excellent, and processing characteristics and shrinkage characteristics, elastic recovery rate, strength and thermal characteristics of the cover for attaching boundary stones can be more effectively improved. On the other hand, if polypropylene is added in an amount of less than 5 parts by weight, processing properties may be deteriorated, making it difficult to mold the product, and if polypropylene is added in an amount exceeding 10 parts by weight, the strength of the product may be reduced due to poor mixing with polylactic acid. there is.

In one example of the present invention, the surface-modified silica with an epoxy group is obtained by coating the surface of silica particles with a silane-based compound containing an epoxy group, and may be obtained by dispersing silica in a silane-based compound containing an epoxy group and then drying it. there is. In this way, by modifying the surface of the silica particles with a silane-based compound containing an epoxy group, mixing and mutual bonding with polylactic acid can be improved.

The amount of silica surface-modified with an epoxy group may be added in an amount of 20 to 50 parts by weight based on 100 parts by weight of polylactic acid. Within this range, the strength and wear resistance of the final product can be effectively increased. On the other hand, if less than 20 parts by weight of silica surface-modified with an epoxy group is added, the strength characteristics and abrasion resistance of the product may be lowered, and if more than 50 parts by weight of silica surface-modified with an epoxy group is added, product defects may occur due to poor mixing. can

In addition, the average particle diameter of the silica particles may be 5 to 50 nm. If the average particle size of the silica particles is too large, it may be difficult to uniformly mix with polylactic acid even if the surface is modified, and if the average particle size is too small, it may be difficult to secure excellent wear resistance performance.

On the other hand, the silane-based compound containing the epoxy group is not particularly limited, but the silane-based compound containing an epoxy group suitable for use in the present invention is 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3- It may be any one or a mixture of two or more selected from the group consisting of glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane.

At this time, an organic solvent may be used to adjust the concentration and viscosity of the silane-based compound containing an epoxy group, and the type may be a commonly used organic solvent. As a specific example, aliphatic hydrocarbons such as hexane and heptane; aromatic hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, isopropanol, butanol, and isobutanol; Ethers, such as a cellusol part and a butyl cellusol part; esters such as ethyl acetate, butyl acetate, and amyl acetate; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; and amides such as N-dimethylformamide and dimethylacetamide; It may be any one or two or more selected from the group consisting of, etc., and preferably aromatic hydrocarbons, alcohols, or mixed solvents thereof may be used, but this is only an example and the present invention is not limited thereto.

The concentration of the silane-based compound containing the epoxy group may be 0.1 to 90% by weight, more preferably 3 to 20% by weight. Within this range, the surface of the silica particles can be effectively modified. In addition, at the time of surface modification, 5 to 30 parts by weight of silica particles may be added to 100 parts by weight of a silane-based compound containing an epoxy group and stirred at a speed of 50 to 150 rpm for 5 to 60 minutes, and then the surface-modified silica particles are separated. and dried for 1 to 24 hours with hot air at 50 to 70° C. to obtain silica surface-modified with an epoxy group.

In one example of the present invention, the emulsifier improves flowability during mixing and molding of each component, increases lubricity so that each component is more uniformly mixed, and shrinkage characteristics and release properties of the final product, the boundary stone attachment cover. It is intended to improve, and if it meets the above purpose, it can be used without particular limitation, but preferably, it is good to use a lipophilic emulsifier, and as a specific example, an emulsifier suitable for use in the present invention is diethylene glycol monostea It may be any one or a mixture of two or more selected from the group consisting of lactate, propylene glycol monostearate, glyceryl monostearate, glyceryl monolinoleate, glyceryl monooleate, and glyceryl monopalmitate.

The emulsifier may be added in an amount of 2 to 5 parts by weight based on 100 parts by weight of polylactic acid. Within this range, flowability and lubricity can be effectively increased, and shrinkage characteristics and releasability of final products can be improved. On the other hand, if the emulsifier is added in an amount of less than 2 parts by weight, productivity of the product may be poor due to lack of flowability and lubricity, and the strength of the molded product may not be constant due to irregular dispersion of the epoxy group surface-modified silica. In addition, if the emulsifier is added in an amount exceeding 5 parts by weight, product defects may occur due to excessive lubrication.

In addition to this, the base layer according to an example of the present invention may further include lyocell fibers. Lyocell fiber is a synthetic fiber derived from cellulose, which is a natural resource, and can be obtained by dry and wet spinning from natural wood or pulp. Such lyocell fiber has the advantage of being biodegradable like polylactic acid, and provides elasticity to the base layer to prevent serious injury to the driver when a car or bicycle collides with a curbstone, and damage to the curbstone attachment cover itself. It has the advantage of reducing the risk.

The amount of the lyocell fiber may be added in an amount of 10 to 20 parts by weight based on 100 parts by weight of polylactic acid. Within this range, the mixing characteristics with polylactic acid may be excellent and the degree of elasticity improvement may be excellent.

In addition, the lyocell fiber may have an average diameter of 10 to 100 nm and an average length of 0.5 to 3 μm. By having such a size, it can be uniformly mixed with other components in the boundary stone attachment cover, while the dimensional stability and elasticity of the boundary stone attachment cover can be increased, and the binding force between each component is further improved, resulting in breakage of the boundary stone attachment cover It has the advantage of reducing the risk.

Next, the reflective layer will be described.

In one example of the present invention, the reflective layer is for imparting a retroreflective effect to a cover for attaching a boundary stone, and as described above, glass beads surface-modified with a fluorine-containing silane-based compound (hereinafter, also referred to as surface-modified glass beads) ) and a polymeric binder, but has a structure in which the surface-modified glass beads protrude to the outside and are embedded in the polymeric binder.

That is, the surface-modified glass beads may have an encapsulated lens type structure in which a partial region is exposed to the outside of the polymer binder. Such a capsule lens type structure can be very useful for a cover for attaching a road curb because the reflected luminance is three times higher than that of a completely enclosed lens type structure.

As a preferred example, it is preferable that the surface-modified glass beads protrude about 1/3 to 2/3 of the diameter of the glass beads, preferably about 2/5 to 3/5 of the diameter of the glass beads. . Some regions of the glass beads whose surfaces are modified to satisfy the above range protrude, and some regions are buried in the polymer binder to have excellent reflective brightness and at the same time to secure excellent adhesion with the polymer binder.

In addition, the area occupied by the surface-modified glass beads may be 40 to 90%, preferably 50 to 70%, based on the total surface area of the polymeric binder layer. In this range, the retroreflection effect may be excellent. However, the area is based on the plane of the surface of the polymeric binder layer without considering the curved structure.

On the other hand, the surface-modified glass beads are components for substantial retroreflection, and bare glass beads that are not surface-modified may have a shape such as a sphere or an ellipse, and preferably have a spherical shape. . The size may vary depending on the product or purpose to which it is applied, but the particle diameter of the glass beads suitable for the present invention may be 10 to 2,000 μm, more preferably 50 to 1,500 μm, and even more preferably 100 to 1,000 μm. Two or more types of glass beads having different sizes may be mixed and used. In addition, the refractive index of the bare glass beads may be greater than or equal to 1.5 index, and more specifically may be 1.5 to 2.5 index. If the refractive index is less than the 1.5 index, retroreflection performance may deteriorate.

In addition, in order to improve adhesion with the polymer binder, the surface of the bare glass beads may be modified with a fluorine-containing silane-based compound. That is, the surface-modified glass beads may have surfaces coated with a fluorine-containing silane-based compound, and may be obtained by dispersing the glass beads in the fluorine-containing silane-based compound and then drying the beads. In this way, by modifying the surface of the glass beads with a fluorine-containing silane-based compound, adhesion to the polymer binder can be improved, and through this, the glass beads can be prevented from being detached from the polymer binder even during long-term use. It has the advantage that the retroreflective property is continuously maintained without deterioration.

In this case, the fluorine-containing silane-based compound may satisfy Formula 1 below.

[Formula 1]

(In Formula 1 above,

R ₁ to R ₃ are each independently an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and at least one of R ₁ to R ₃ is an alkoxy group;

X is a fluoroalkyl group having 1 to 12 carbon atoms;

n is an integer from 1 to 10.)

By using the glass beads surface-modified with a compound satisfying Formula 1, the hydrophobicity of the glass beads is improved, so that they can better adhere to the polymer binder.

As a specific example, the fluorine-containing silane-based compound is trifluoromethyl trimethoxysilane, trifluoromethyl triethoxysilane, trifluoropropyl trimethoxysilane, trifluoropropyl triethoxysilane, nonafluoro Robutylethyl trimethoxysilane, nonafluorobutylethyl triethoxysilane, nonafluorohexyl trimethoxysilane, nonafluorohexyl triethoxysilane, tridecafluorooctyl trimethoxysilane, tridecafluoro It is selected from the group consisting of octyl triethoxysilane, heptadecafluorodecyl trimethoxysilane, heptadecafluorodecyl triethoxysilane, trifluoropropyl methyldimethoxysilane, and trifluoropropyl methyldiethoxysilane. It may be any one or a mixture of two or more, but is not necessarily limited thereto.

At this time, an organic solvent may be used to adjust the concentration and viscosity of the fluorine-containing silane-based compound, and the type may be a commonly used organic solvent. As a specific example, aliphatic hydrocarbons such as hexane and heptane; aromatic hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, isopropanol, butanol, and isobutanol; Ethers, such as a cellusol part and a butyl cellusol part; esters such as ethyl acetate, butyl acetate, and amyl acetate; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; and amides such as N-dimethylformamide and dimethylacetamide; It may be any one or two or more selected from the group consisting of, etc., and preferably aromatic hydrocarbons, alcohols, or mixed solvents thereof may be used, but this is only an example and the present invention is not limited thereto.

The concentration of the fluorine-containing silane-based compound may be 0.1 to 90% by weight, more preferably 3 to 20% by weight. Within this range, the surface of the glass beads can be effectively modified. In addition, at the time of surface modification, 5 to 30 parts by weight of glass beads may be added to 100 parts by weight of the fluorine-containing silane-based compound and stirred at a speed of 50 to 150 rpm for 5 to 60 minutes, and then the surface-modified glass beads are separated, Glass beads surface-modified with a fluorine-containing silane-based compound may be obtained by drying for 1 to 24 hours with hot air at 50 to 70°C.

In addition, the surface-modified glass beads with the fluorine-containing silane-based compound may be pre-treated with a basic solution before being surface-modified with the fluorine-containing silane-based compound.

In this way, by pre-treating the bare glass beads with a basic solution, more active hydroxyl groups (-OH) can be present on the surface of the glass beads, and the active hydroxyl group reacts with the silane of the fluorine-containing silane-based compound to form a Si-O covalent bond. By forming the glass beads and the fluorine-containing silane-based compound can be more firmly bonded.

In one example of the present invention, the basic solution is not particularly limited as long as it contains a hydroxyl group, but may be, for example, any one selected from the group consisting of an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, and a calcium hydroxide solution, or a mixture of two or more. The concentration of the basic solution may be 0.1 to 5 M, more preferably 1 to 3 M, but is not necessarily limited thereto. It is good to be able to form

On the other hand, the polymer binder according to one embodiment of the present invention serves as a support layer in which a partial region of glass beads is embedded, and it is preferable to use a polymer binder having excellent adhesive strength between the glass beads and the base layer. As a specific example, an acrylic binder, Any one or two or more adhesive resins selected from the group consisting of urethane-based binders, silicone-based binders, epoxy-based binders, polyvinyl chloride-based binders, polyethylene-based binders and polyester-based binders may be used, particularly preferably polydimethyl The use of a silicon-based binder such as a siloxane (PDMS) resin is better for firmly binding the surface-modified glass beads to the polymer binder. At this time, the weight average molecular weight of the silicon-based binder may be 3,000 to 300,000 g / mol, and more preferably 10,000 to 100,000 g / mol, but this is only an example, and the present invention is not necessarily limited thereto.

The thickness of the polymeric binder layer is sufficient to sufficiently embed a partial area of the surface-modified glass beads, for example, 3 to 1,000 μm, but is not necessarily limited thereto, and depending on the diameter of the glass beads, the polymer Of course, the thickness of the binder layer may vary.

Next, the transparent protective layer will be described.

The transparent protective layer is intended to more reliably prevent the surface-modified glass beads from being detached by an external force such as moisture or impact. The transparent protective layer has excellent transparency and a curved structure corresponding to the surface-modified glass beads of the reflective layer. By having it, it is possible to prevent the reflection luminance of the surface-modified glass beads from being lowered.

For example, the transparent protective layer may include a UV-curable resin, and more specifically, the UV-cured acrylic resin is prepared by UV-curing a protective layer composition including an acrylate-based oligomer, an acrylate-based monomer, and a photoinitiator. may have been

The acrylate-based oligomer is a polymer having a relatively low degree of polymerization obtained by polymerizing an acrylate-based monomer having two or more acryl groups, acryloyl groups, methacryl groups or methacryloyl groups in a molecule, and as a specific example, urethane (methacrylic acid) ) It may be any one or two or more selected from the group consisting of acrylate, polyester (meth) acrylate, and epoxy (meth) acrylate. The acrylate-based oligomer may be included in 30 to 85% by weight, preferably 60 to 80% by weight, based on the total weight of the protective layer composition.

The weight average molecular weight of the acrylate-based oligomer may be 1000 to 5000 g/mol, but is not necessarily limited thereto.

The acrylate-based monomer is for controlling the viscosity and the degree of crosslinking density, and as a specific example, hexyl (meth) acrylate, ethylhexyl 2- (meth) acrylate, isobornyl (meth) acrylate, isooctyl It may be any one or two or more selected from the group consisting of (meth)acrylate, 1,6-hexanediol (meth)acrylate, and neopentylglycol di(meth)acrylate. The acrylate-based monomer may be included in an amount of 5 to 60% by weight, preferably 10 to 35% by weight, based on the total weight of the protective layer composition.

The photoinitiator is to form radicals when irradiated with ultraviolet light so that photopolymerization can occur, and any known compound may be used, but it is preferable to select and use a photoinitiator suitable for the wavelength range of ultraviolet rays used during curing. As a specific example, benzophenone and substituted benzophenones, 1-hydroxycyclohexyl phenyl ketone, thioxanthone such as isopropylthioxanthone, 2-hydroxy-2-methyl-1-phenylpropan-1-one , 2-benzyl-2-dimethylamino-(4-morpholinophenyl)butan-1-one, benzyl dimethylketal, bis(2,6-dimethylphenzoyl)-2,4,4-trimethylpentylphosphine oxide , 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl-2,4,6-trimethylbenzoylphenylphosphinate, 2-methyl-1-[4-(methylthio)phenyl]-2-morphopoly Nopropan-1-one, 2,2-dimethoxy-1,2-diphenylethan-1-one or 5,7-diiodo-3-butoxy-6-fluorone, diphenyliodonium fluoride And it may be any one or two or more selected from the group consisting of triphenylsulfonium hexafluorophosphate and the like. The photoinitiator may be included in 1 to 15% by weight, preferably 5 to 10% by weight, based on the total weight of the protective layer composition.

In addition, at this time, the transparency of the transparent protective layer is preferably 80% or more, preferably 90% or more.

The thickness of the transparent protective layer is sufficient to form a curved structure corresponding to the surface-modified glass beads while effectively protecting the surface-modified glass beads, for example, 1 to 300 μm, more preferably 10 to 10 μm. It is preferable to have a thickness of 100 μm. Within the above range, the surface of the curved surface structure can be easily formed, and the surface-modified glass beads can be effectively protected.

In addition, another aspect of the present invention is a) molding a base composition comprising 5 to 10 parts by weight of polypropylene, 20 to 50 parts by weight of silica surface-modified with an epoxy group, and 2 to 5 parts by weight of an emulsifier based on 100 parts by weight of polylactic acid to form a base layer; b) forming a reflective layer by applying a polymeric binder on the base layer and burying a portion of glass beads surface-modified with a fluorine-containing silane-based compound on top of the polymeric binder so as to protrude; and c) forming a transparent protective layer on the reflective layer.

First, a) forming a base layer by molding a base composition comprising 5 to 10 parts by weight of polypropylene, 20 to 50 parts by weight of silica surface-modified with an epoxy group, and 2 to 5 parts by weight of an emulsifier, based on 100 parts by weight of polylactic acid. can be performed.

At this time, since the constituent components of the base composition are the same as the above-mentioned boundary stone attachment cover, duplicate descriptions will be omitted.

When the base composition is prepared, a base layer may be formed by molding the base composition.

At this time, the molding may be performed by a method commonly used in the art, for example, melt extrusion of the base composition or pelletizing the base composition to prepare a pellet chip, and then the pellet chip in a mold. The base layer may be prepared by injection molding, which may be performed by a commonly known method.

Next, b) coating a polymer binder on the base layer, and forming a reflective layer by embedding a portion of glass beads surface-modified with a fluorine-containing silane-based compound on top of the polymer binder so as to protrude. .

The method of applying the polymer binder may be performed by a conventional method, for example, spin coating, bar coating, screen printing, spray coating, doctor blade coating, gravure coating, dip coating, silk screen, or slot die die), etc., but is not limited thereto, and all coating methods that can be used in the art may be used.

At this time, an organic solvent may be used for viscosity control and easy application of the polymeric binder, and the type may be a commonly used organic solvent. As a specific example, aliphatic hydrocarbons such as hexane and heptane; aromatic hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, isopropanol, butanol, and isobutanol; Ethers, such as a cellusol part and a butyl cellusol part; esters such as ethyl acetate, butyl acetate, and amyl acetate; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; and amides such as N-dimethylformamide and dimethylacetamide; It may be any one or two or more selected from the group consisting of, etc., and preferably aromatic hydrocarbons, alcohols, or mixed solvents thereof may be used, but this is only an example and the present invention is not limited thereto.

Thereafter, before the polymer binder is completely dried or cured, the surface-modified glass beads may be embedded in the polymer binder to an appropriate depth, and at this time, pressure for adjusting the embedding depth may be applied.

Additionally, a process for drying or curing the polymeric binder may be performed, which may be performed by a conventional method.

Next, c) forming a transparent protective layer on the reflective layer may be performed. The method of forming the transparent protective layer may be performed by a conventional method, and as described above, the protective layer composition may be coated on the reflective layer and then cured by ultraviolet rays to form the transparent protective layer. At this time, it is important to form a transparent protective layer to have an appropriate thickness in order to form a curved structure corresponding to the surface-modified glass beads. Forming a transparent protective layer to have a thickness of 100 μm is good in securing excellent retroreflective luminance.

Hereinafter, a cover for attaching a boundary stone according to the present invention and a manufacturing method thereof will be described in more detail through examples. However, the following examples are only one reference for explaining the present invention in detail, but the present invention is not limited thereto, and may be implemented in various forms.

Also, unless defined otherwise, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description herein is merely to effectively describe specific embodiments and is not intended to limit the present invention. In addition, the unit of additives not specifically described in the specification may be % by weight.

[Production Example 1]

Bare glass beads (500 μm in diameter) were put in aqueous sodium hydroxide solution (1 M) and treated at 90° C. for 2 hours, then washed with water and dried. Next, 25 parts by weight of alkali-treated glass beads were mixed with 100 parts by weight of a trifluoropropyl trimethoxysilane solution (5% by weight in isopropyl alcohol), stirred for 30 minutes, and the surface-modified glass beads were separated by filtration. After drying for 2 hours in air at room temperature, surface-modified glass beads were prepared.

[Production Example 2]

After mixing 25 parts by weight of bare glass beads (500 μm in diameter) with respect to 100 parts by weight of trifluoropropyl trimethoxysilane solution (5% by weight in isopropyl alcohol), stirring for 30 minutes, the surface-modified After separating the glass beads by filtration, they were dried for 2 hours in air at room temperature to prepare surface-modified glass beads.

[Comparative Manufacturing Example 1]

Bare glass beads (500 μm in diameter) without surface modification were prepared.

[Comparative Manufacturing Example 2]

Bare glass beads (500 μm in diameter) were put in aqueous sodium hydroxide solution (1 M), treated at 90° C. for 2 hours, washed with water and dried to prepare glass beads surface-modified with hydroxyl groups.

[Example 1]

Based on 100 parts by weight of polylactic acid (PL, weight average molecular weight (Mw) 16,500 g/mol), polypropylene homopolymer (PP, weight average molecular weight (Mw) 450,000 g/mol) 5 parts by weight, silica surface-modified with an epoxy group A base composition was prepared by mixing 20 parts by weight and 2 parts by weight of glyceryl monostearate (GMS). Thereafter, the base composition was melted at 200° C. for 2 hours while stirring, and then extruded through an extruder to prepare a base layer having a thickness of 5 mm. At this time, the surface-modified silica with the epoxy group is mixed with 25 parts by weight of silica particles (average particle diameter of 30 nm) with respect to 100 parts by weight of a 3-glycidoxypropyltriethoxysilane solution (5% by weight in isopropyl alcohol), and then 30 It was prepared by stirring for 2 minutes, filtering the surface-modified silica with an epoxy group, and drying for 2 hours with wind at room temperature.

Next, liquid polydimethylsiloxane (PDMS, Dow Corning, Sylgard 184 A/B) is spin-coated on the base layer, and then 1/2 of the diameter (250 μm) is embedded on the PDMS. The surface-modified glass beads of Example 1 were applied and cured in an oven at 60° C. for 6 hours to prepare a reflective layer.

Next, urethane acrylate (weight average molecular weight (Mw) 3,600 g / mol) 73% by weight, 1,6-hexanediol acrylate 15% by weight, isobornyl methacrylate 5% by weight and Irgacure 184 (Irgacure 184 ) 7% by weight of the mixed protective layer composition was applied on the reflective layer and then cured through ultraviolet irradiation to form a transparent protective layer having a thickness of 20 μm.

[Example 2]

All processes were the same as in Example 1 except that a base composition was prepared by mixing 8 parts by weight of polypropylene homopolymer, 35 parts by weight of epoxy group surface-modified silica, and 3.5 parts by weight of glyceryl monostearate with respect to 100 parts by weight of polylactic acid. proceeded.

[Example 3]

All processes were the same as in Example 1 except that a base composition was prepared by mixing 10 parts by weight of polypropylene homopolymer, 50 parts by weight of epoxy group surface-modified silica, and 5 parts by weight of glyceryl monostearate with respect to 100 parts by weight of polylactic acid. proceeded.

[Example 4]

All processes were performed in the same manner as in Example 2, except that the surface-modified glass beads of Preparation Example 2 were used.

[Comparative Example 1]

All processes were the same as in Example 1 except that the base composition was prepared by mixing 1 part by weight of polypropylene homopolymer, 10 parts by weight of epoxy group surface-modified silica, and 1 part by weight of glyceryl monostearate with respect to 100 parts by weight of polylactic acid. proceeded.

[Comparative Example 2]

All processes were the same as in Example 1 except that a base composition was prepared by mixing 15 parts by weight of polypropylene homopolymer, 80 parts by weight of epoxy group surface-modified silica, and 10 parts by weight of glyceryl monostearate with respect to 100 parts by weight of polylactic acid. proceeded.

[Comparative Example 3]

All processes were performed in the same manner as in Example 1 except for using silica particles (average particle diameter of 30 nm) whose surface was not modified.

[Comparative Example 4]

All processes were performed in the same manner as in Example 2, except that the bare glass beads of Comparative Preparation Example 1 were not surface-modified.

[Comparative Example 5]

All processes were performed in the same manner as in Example 2 except that the glass beads surface-modified with hydroxyl groups of Comparative Preparation Example 2 were used.

Base layer (parts by weight) reflective layer PL PP surface modified silica GMS Glass bead surface modification glass bead alkali
process silane treatment Diameter (μm) Protrusion size (μm) Example 1 100 5 20 2 ○ ○ 500 250 Example 2 8 35 3.5 Example 3 10 50 5 Example 4 100 8 35 3.5 x ○ 500 250 Comparative Example 1 100 One 10 One ○ ○ 500 250 Comparative Example 2 15 80 10 Comparative Example 3 8 35
(surface
unreformed) 3.5 Comparative Example 4 100 8 35 3.5 x x 500 250 Comparative Example 5 ○ x

[Characteristic evaluation method]

The physical properties of the cover specimens for attaching boundary stones prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were evaluated through the following methods, and the results are shown in Table 2 below.

1) Processability: The state of the base layer specimen was visually observed after extrusion molding, and X was indicated when cracks occurred or moldability defects such as distortion occurred in the base layer specimen, and ○ when there was no visual problem.

2) Impact resistance (kg cm/cm): The impact strength of the base layer specimen was measured by the Izod method under room temperature conditions in accordance with ASTM D-256.

3) Retroreflective luminance (mcd/(㎡·lux)): Using a retroreflective luminance meter ((USA, Gamma Scientific, ART 930B) at 0.2/-4° (observation angle/incidence angle), recursive reflection of the cover specimen for boundary stone attachment After measuring the reflected luminance 10 times, the average value was calculated.

4) Adhesion: The adhesive force between the polymer binder and the glass beads was measured. In detail, a specimen with a reflective layer formed on the base layer (no transparent protective layer formed) was left at room temperature for 2 days, and then an adhesive tape with a width of 50 mm was applied to the surface of the specimen (adhesive strength: 6 N per 25 mm width) After attaching, peeling was attempted. As a result, when the surface-modified glass beads are peeled at less than 3% by weight (based on the total weight of the surface-modified glass beads of the reflective layer), excellent, when peeled at 3 to 10% by weight is good, and when peeled at more than 10% by weight It was evaluated as poor.

machinability impact strength
(kg cm/cm) retroreflective luminance
(mcd/(㎡·lux)) adhesion Example 1 ○ 19.5 284 Great Example 2 ○ 20.0 287 Great Example 3 ○ 20.8 282 Great Example 4 ○ 21.6 285 Great Comparative Example 1 ○ 13.3 282 Great Comparative Example 2 X 18.0 284 Great Comparative Example 3 X 7.9 281 Great Comparative Example 4 ○ 19.9 286 error Comparative Example 5 ○ 19.9 283 error

As can be seen from Table 2, in the case of Examples 1 to 4 in which each component was added in an appropriate amount according to the present invention, the workability, shrinkage and impact resistance of the base layer were all excellent, and the retroreflection of the reflective layer was excellent. Brightness and adhesion were also very good.

On the other hand, in the case of Comparative Example 1, other components were added in a small amount compared to polylactic acid, so the shrinkage rate was too high and the impact resistance was also low. In the case of Comparative Example 2, excessive amounts of other components compared to polylactic acid were added, resulting in cracks and distortion in the final product. In the case of Comparative Example 3, silica particles without surface modification were used, and cracks occurred in the final product due to poor miscibility with polylactic acid, and impact resistance was greatly reduced.

In Comparative Examples 4 and 5, since bare glass beads without surface modification or alkali treated glass beads were used, adhesion to the polymer binder was not good.

Although the present invention has been described through specific details and limited examples as described above, this is only provided to help a more general understanding of the present invention, the present invention is not limited to the above examples, and the present invention belongs Various modifications and variations from these descriptions are possible to those skilled in the art.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and it will be said that not only the claims to be described later, but also all modifications equivalent or equivalent to these claims belong to the scope of the present invention. .

100: base layer
200: reflective layer
210: surface modified glass beads
220: polymer binder
300: transparent protective layer

Claims (13)

A base layer containing polylactic acid;
It is formed on the base layer and includes glass beads surface-modified with a fluorine-containing silane-based compound and a polymer binder, wherein the glass beads surface-modified with the fluorine-containing silane-based compound are embedded in the polymer binder in a structure in which they protrude to the outside. reflective layer; and
A transparent protective layer formed on the reflective layer and having a curved structure corresponding to the glass beads surface-modified with a fluorine-containing silane-based compound;
The polymer binder is a polydimethylsiloxane (PDMS) resin having a weight average molecular weight of 3,000 to 300,000 g / mol, a cover for attaching a boundary stone.
According to claim 1,
The fluorine-containing silane-based compound is a cover for attaching a boundary stone that satisfies Formula 1 below.
[Formula 1]

(In Formula 1,
R ₁ to R ₃ are each independently an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and at least one of R ₁ to R ₃ is an alkoxy group;
X is a fluoroalkyl group having 1 to 12 carbon atoms;
n is an integer from 1 to 10.)
According to claim 1,
The surface-modified glass beads with the fluorine-containing silane-based compound are pre-treated with a basic solution before being surface-modified with the fluorine-containing silane-based compound.
According to claim 3,
The basic solution is any one or a mixture of two or more selected from the group consisting of an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution and calcium hydroxide, a cover for attaching a boundary stone.
According to claim 1,
The base layer comprises 5 to 10 parts by weight of polypropylene, 20 to 50 parts by weight of silica surface-modified with an epoxy group, and 2 to 5 parts by weight of an emulsifier, based on 100 parts by weight of polylactic acid.
According to claim 5,
The weight average molecular weight of the polylactic acid is 10,000 to 20,000 g / mol, a cover for attaching a boundary stone.
According to claim 5,
The weight average molecular weight of the polypropylene is 300,000 to 1,000,000 g / mol, the boundary stone attachment cover.
According to claim 5,
The surface-modified silica with the epoxy group is a cover for attaching a boundary stone to which the surface of the silica particle is coated with a silane-based compound containing an epoxy group.
According to claim 8,
The silane-based compound containing the epoxy group includes 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane and 3-glycidoxypropylmethyldiethoxysilane. Any one or a mixture of two or more selected from the group consisting of glycidoxypropyltriethoxysilane, a cover for attaching a boundary stone.
According to claim 5,
The emulsifier is any one or two or more selected from the group consisting of diethylene glycol monostearate, propylene glycol monostearate, glyceryl monostearate, glyceryl monolinoleate, glyceryl monooleate and glyceryl monopalmitate A mixture, a cover for attaching boundary stones.
delete According to claim 1,
The transparent protective layer is prepared by UV-curing a protective layer composition containing an acrylate-based oligomer, an acrylate-based monomer and a photoinitiator, a cover for attaching a boundary stone.
a) forming a base layer by molding a base composition comprising 5 to 10 parts by weight of polypropylene, 20 to 50 parts by weight of silica surface-modified with an epoxy group, and 2 to 5 parts by weight of an emulsifier based on 100 parts by weight of polylactic acid;
b) forming a reflective layer by applying a polymeric binder on the base layer and burying a portion of glass beads surface-modified with a fluorine-containing silane-based compound on top of the polymeric binder so as to protrude; and
c) forming a transparent protective layer on the reflective layer;
The polymeric binder is a polydimethylsiloxane (PDMS) resin having a weight average molecular weight of 3,000 to 300,000 g / mol, a method for producing a cover for attaching a boundary stone.