Artificial turf back-coating composition and method for manufacturing artificial turf using the same

Abstract

The present invention relates to an artificial turf back coating composition comprising a main component including an isocyanate prepolymer and a curing agent composition comprising a thermogenic catalyst and a non-expanding thermally expandable hollow filler, wherein the main component and the curing agent composition are mixed to form a coating layer having embossed protrusions with excellent shock absorption properties, wherein at room temperature, the curing reaction is suppressed by the thermogenic catalyst, allowing application by a roller or flat knife, and under heating conditions, the activation of the thermogenic catalyst and the expansion of the hollow filler occur simultaneously.

Description

Technology Field

[0001] The present invention relates to an artificial turf back coating composition and a method for manufacturing artificial turf using the same. More specifically, the invention relates to an artificial turf back coating composition that allows for application by a roller or flat knife by suppressing the curing reaction at room temperature, and forms a coating layer having embossed protrusions with excellent shock absorption properties by curing simultaneously with the expansion of non-expanding, thermally expandable hollow fillers under heating conditions. Background Technology

[0003] Artificial turf is widely used as a replacement for natural grass for various purposes such as sports fields, landscaping facilities, and playgrounds, and demand is continuously increasing due to advantages such as year-round usability and ease of maintenance.

[0004] Artificial turf is generally manufactured by implanting polyethylene or polypropylene-based pile yarns into a base sheet in the form of a woven or non-woven fabric made of synthetic resin using a tufting method, and a back coating layer is formed on the back of the base sheet to prevent the pile yarns from falling off and to ensure mechanical strength.

[0005] Early artificial turf back coating layers were primarily manufactured based on SBR latex.

[0006] Latex has the advantages of excellent workability and low cost, but it has limitations such as low water resistance, making the back coating layer susceptible to damage during rain, low tensile strength for holding pile yarns, and poor shock absorption.

[0007] In addition, the latex-based coating layer deteriorates with long-term use, frequently causing the pile fibers to detach.

[0008] Polyurethane-based back-coating technology was introduced as an alternative to compensate for the disadvantages of latex.

[0009] The polyurethane coating layer exhibits superior physical properties compared to latex in terms of water resistance, shock absorption, and tensile strength.

[0010] However, since polyurethane has the characteristic that when an isocyanate-based main component and a polyol-based curing agent are mixed, the curing reaction starts immediately even at room temperature and gelation proceeds within minutes, there is a problem that sufficient working time cannot be secured when applying it to the back of a sheet using a roller, as with latex.

[0011] For this reason, conventional polyurethane back-coating technology has mainly adopted high-pressure spray methods.

[0012] However, in the spray method, a significant amount of coating material is scattered in the form of fine droplets during the spraying process, so the actual amount applied to the back of the sheet is only about 60% of the input amount, and the remaining about 40% is scattered in the form of dust, causing material loss and contamination of the working environment.

[0013] Furthermore, since curing proceeds within minutes of mixing the main component and the hardener, there is a time constraint requiring the spraying operation to be completed immediately after mixing. This restricts the freedom to stop or resume work, and results in losses due to the curing and disposal of residual coating material in the tank.

[0014] In addition, the coating layer formed by spraying has a flat structure, which limits the structural improvement of shock absorption.

[0015] In this regard, Registered Patent No. 10-1265166 discloses a technology for applying a thermosetting resin-based back coating material containing polyurethane to the back surface of a foam sheet in an artificial turf structure reinforced with a back coating of a functional material.

[0016] However, this technology has limitations in that it fails to fundamentally solve the technical challenges of improving application workability and enhancing shock absorption by moving away from the spray method, as there is no specific disclosure regarding means for controlling the curing speed of polyurethane at room temperature or component composition for spontaneously forming a shock-absorbing structure in the coating layer.

[0017] Therefore, there is a need to develop a new artificial turf back coating composition that maintains fluidity for more than one hour at room temperature, enabling direct application using a roller or flat knife, and simultaneously forms a shock-absorbing structure within the coating layer while curing under heating conditions. Prior art literature

[0019] Registered Patent No. 10-1265166 The problem to be solved

[0020] The present invention was developed to improve upon the aforementioned problems and aims to provide an artificial turf back coating composition and a method for manufacturing artificial turf using the same, comprising a main component containing an isocyanate prepolymer and a curing agent composition containing a thermochromic catalyst and a non-expanding thermally expandable hollow filler, wherein at room temperature, the urethane curing reaction is suppressed by the thermochromic catalyst, thereby ensuring sufficient working time and enabling the coating agent to be directly applied to the back of a sheet using a roller or a flat knife.

[0021] In addition, the present invention aims to provide an artificial turf back coating composition and a method for manufacturing artificial turf using the same, which enables the realization of a coating layer with excellent shock absorption without the need for a separate elastic pad or filler by simultaneously activating a thermosensitive catalyst and expanding a non-expandable thermally expandable hollow filler during a heating process passing through a heating chamber, thereby forming embossed protrusions together with the coating layer at once.

[0022] Furthermore, the present invention aims to provide an artificial turf back coating composition and a method for manufacturing artificial turf using the same, which eliminates the scattering loss of the coating agent at its source by adopting a direct application method using a roller or a flat knife instead of a spray method, thereby maximizing material usage efficiency and preventing contamination of the working environment caused by dust generation.

[0023] In addition, the present invention aims to provide an artificial turf back coating composition and a method for manufacturing artificial turf using the same, wherein the curing agent composition comprises a non-expanding thermally expandable hollow filler having an average particle diameter of 10 to 16 μm and an expansion temperature of 80 to 100°C, and a delayed catalyst which is a composite of DBU and octanoate, so that the curing activation time in the heating chamber coincides with the expansion time of the hollow filler, thereby enabling the formation of uniform embossed protrusions on the surface of the coating layer.

[0024] In addition, the present invention aims to provide an artificial turf back coating composition and a method for manufacturing artificial turf using the same, which can satisfy safety and performance standards required at artificial turf stadium construction sites by providing artificial turf having a tensile strength of 80N or more and shock absorption of 20% or more according to the KS F 3888-1 test method and having embossed protrusions with a height of 2 to 5 mm on the back surface of the coating layer. means of solving the problem

[0026] To achieve the above objectives, the present invention may provide an artificial turf backcoating composition comprising: a main component comprising an isocyanate prepolymer; and a curing agent composition comprising a thermochromic catalyst and a non-expanding thermally expandable hollow filler, wherein the main component and the curing agent composition are mixed.

[0027] Here, the curing agent composition is characterized by comprising, with respect to 100 parts by weight of polyether polyol, 1 to 9 parts by weight of a non-expanding thermally expandable hollow filler, 0.1 to 5 parts by weight of a thermochromic catalyst, 12 to 34 parts by weight of an amine for chain extenders, and 12 to 34 parts by weight of polybutadiene polyol.

[0028] At this time, the non-expandable thermally expandable hollow filler is characterized by having an average particle diameter of 10 to 16 μm, containing a hydrocarbon gas inside, being surrounded by a thermoplastic polymer shell on the outside, and having an expansion temperature of 80 to 100°C.

[0029] In addition, the above-mentioned thermostatic catalyst is characterized as a delayed catalyst that is a complex composed of DBU (1,8-diazabicyclo[5.4.0]undecane-7-ene) and octanoate.

[0030] In addition, the above-mentioned subject comprises a urethane prepolymer having an NCO content of 10 to 18%, and is characterized by a mixing ratio (substance / curing agent index) of the above-mentioned subject and the above-mentioned curing agent composition being a weight ratio of 0.9:1 to 1.5:1.

[0031] In addition, the polybutadiene polyol is characterized by having a Cis-1,4 polybutadiene content of 80% or more and a weight-average molecular weight of 2,000 to 5,000.

[0032] Meanwhile, the present invention may also provide artificial turf having a coating layer formed of a back coating composition, wherein the coating layer has a tensile strength of 80 N or more and an impact absorption capacity of 20% or more according to the KS F 3888-1 test method, and the back surface of the coating layer has embossed protrusions with a height of 2 to 5 mm formed thereon. Effects of the invention

[0034] According to the present invention with the above-described configuration, the following effects can be achieved.

[0035] First of all, the present invention has the advantage of simultaneously improving work convenience and material efficiency by including a thermochromic catalyst in the curing agent composition, thereby maintaining fluidity at room temperature for more than 1 hour even after mixing the main component and the curing agent, enabling application work using a roller or flat knife, and preventing material loss due to spontaneous curing of the coating agent while stored in a tank.

[0036] In addition, the present invention has the advantage of being able to achieve excellent shock absorption by including a non-expanding thermally expandable hollow filler in the curing agent composition, thereby spontaneously forming embossed protrusions with a height of 2 to 5 mm on the surface of the coating layer by the expansion of the hollow filler when passing through a heating chamber, and absorbing external impact energy through the deformation of the protrusion structure.

[0037] In addition, the present invention has the advantage of being able to implement a coating layer that satisfies a tensile strength of 80N or more and an impact absorption of 20% or more according to the KS F 3888-1 test method without a separate elastic pad or filler, due to the technical synergy in which catalyst activation and hollow filler expansion occur simultaneously at the time of heating in the heating chamber by combining a thermosensitive catalyst and a non-expandable thermally expandable hollow filler.

[0038] In addition, the present invention has the advantage of replacing the conventional spray method with a direct application method using a roller or a flat knife, thereby applying the entire amount of the injected coating agent to the back of the sheet, dramatically improving material usage efficiency compared to the conventional spray method, and significantly improving the working environment by eliminating dust generation.

[0039] In addition, the present invention has the advantage of being able to be installed stably without slipping even on wet concrete surfaces by including a polybutadiene polyol having a Cis-1,4 polybutadiene content of 80% or more and a weight-average molecular weight of 2,000 to 5,000 in the curing agent composition, so that the coating layer has excellent elastic recovery, making it easy to spread artificial turf during winter field work.

[0040] Furthermore, the present invention has the distinctive advantage of preventing flooding of the artificial turf surface and improving playability by adopting a configuration in which drainage holes are formed by a perforation means after the coating layer is completely cured, thereby allowing rainwater to drain smoothly during rain while maintaining the structural integrity of the coating layer.

[0041] In addition, the present invention has the advantage that the polyurethane-based coating layer has a higher surface friction coefficient compared to conventional latex-based coating layers, thereby significantly reducing slipping when a player runs or changes direction on the artificial turf surface, preventing falls during the game, and improving game safety.

[0042] In addition, the method for manufacturing artificial turf according to the present invention maintains the temperature of the heating chamber in the range of 80 to 120°C, thereby completing the curing under conditions lower than the drying temperature of the existing latex-based back-coating process, so that shrinkage, curing, and damage caused by heat of the pile yarn are minimized.

[0043] As a result, the pile yarn of the finished artificial turf maintains a flexible and soft texture, and even if the player's skin rubs against the surface of the turf, the rise in the surface temperature of the pile yarn is suppressed, which has the advantage of significantly lowering the possibility of skin thermal burns. Brief explanation of the drawing

[0045] FIG. 1 is a conceptual diagram illustrating the overall configuration of an artificial turf manufacturing apparatus using an artificial turf back coating composition according to one embodiment of the present invention. Figure 2 is an enlarged conceptual diagram showing a cross-sectional structure of artificial turf with a coating layer and embossed protrusions formed after passing through the heating chamber shown in Figure 1. FIG. 3 is an enlarged conceptual diagram illustrating a finished artificial turf cross-sectional structure in which drainage holes are formed by the perforation means shown in FIG. 1. Specific details for implementing the invention

[0046] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described in detail below together with the accompanying drawings.

[0047] However, the present invention is not limited to the embodiments disclosed below but will be implemented in various different forms.

[0048] The embodiments described in this specification are provided to ensure that the disclosure of the invention is complete and to fully inform those skilled in the art of the scope of the invention.

[0049] And the present invention is defined only by the scope of the claims.

[0050] Accordingly, in some embodiments, well-known components, well-known operations, and well-known techniques are not specifically described to avoid the invention being interpreted ambiguously.

[0051] Additionally, throughout the specification, the same reference numerals refer to the same components, and the terms used (mentioned) in this specification are for describing embodiments and are not intended to limit the invention.

[0052] In this specification, the singular form includes the plural form unless specifically stated otherwise in the text, and components and operations referred to as 'comprising (or comprising)' do not exclude the presence or addition of one or more other components and operations.

[0053] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning that is commonly understood by those skilled in the art to which the present invention belongs.

[0054] Also, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless otherwise defined.

[0055] Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings.

[0057] First, FIG. 1 is a conceptual diagram illustrating the overall configuration of an artificial turf manufacturing device using an artificial turf back coating composition according to one embodiment of the present invention, schematically showing the entire manufacturing line in which a perforating drum (300), a coating means (400), a heating chamber (500), and a perforating means (600) are sequentially arranged along a flow in which a sheet (100) inverted so that the pile yarn (110) faces downward is transported in one direction on a conveyor (200).

[0058] And, FIG. 2 is an enlarged cross-section of a sheet (100) after passing through a heating chamber (500) shown in FIG. 1, showing a structure in which a coating layer (700) is formed on the rear surface of the sheet (100) and an embossing protrusion (710) is formed on the surface of the coating layer (700) by the expansion of a non-expanding thermally expandable hollow filler.

[0059] In addition, FIG. 3 is an enlarged view of the cross-sectional structure of a finished artificial turf in which a drainage hole (720) is formed by the perforation means (600) shown in FIG. 1, showing a final structure in which a pile yarn (110) penetrates the sheet (100) and is fixed downward, and a drainage hole (720) is formed on the rear surface of the coating layer (700).

[0061] The present invention comprises, as shown in FIGS. 1 to 3, a main component including an isocyanate prepolymer and a curing agent composition including a thermochromic catalyst and a non-expanding thermally expandable hollow filler, and an artificial turf back coating agent composition formed by mixing the main component and the curing agent composition as an essential component.

[0063] The above subject is based on an isocyanate prepolymer, specifically using a urethane prepolymer prepared by reacting a methylene diphenyl isocyanate-based compound with a polyether polyol.

[0064] NCO (%), the isocyanate content of the above subject, is an indicator that directly affects the final physical properties of the cured product; as NCO increases, hardness and reactivity increase, and as NCO decreases, flexibility and shock absorption improve.

[0065] The subject of the present invention is preferably an NCO content of 10 to 18%, and if the NCO is less than 10%, the curing speed becomes excessively slow, which reduces productivity, and if the NCO exceeds 18%, the hardness increases excessively, making it difficult to wind the finished artificial turf into a roll shape and reducing shock absorption.

[0067] The above curing agent composition comprises a non-expanding thermally expandable hollow filler, a thermochromic catalyst, an amine for chain extenders, a polyether polyol, and a polybutadiene polyol, and each component is described in detail below.

[0069] The above-mentioned non-expandable thermally expandable hollow filler is a component that improves shock absorption by forming a pore structure inside the coating layer (700) under heating conditions.

[0070] The non-expandable thermally expandable hollow filler used in the present invention has an average particle diameter of 10 to 16 μm, contains a hydrocarbon gas such as isobutane or isopentane inside, and has a structure surrounded by a thermoplastic polymer shell on the outside.

[0071] This hollow filler has the characteristic that the particle diameter increases by more than tens of times due to the expansion of internal gas as the thermoplastic polymer shell softens under heating conditions of 80 to 100°C. The reason for using a non-expanding hollow filler that is not expanded before heating in this way stems from the technical linkage with the thermosensitive catalyst described later.

[0073] The above thermochromic catalyst is a component that plays the most critical role in the present invention and has the function of suppressing the urethane reaction at room temperature and releasing catalytic active species only under heating conditions of 80 to 120°C to induce rapid curing.

[0074] The principle by which the thermochromic catalyst inhibits the reaction at room temperature is that when the catalytic active species DBU forms a complex with the octanoate, the catalytic activity for the urethane reaction is significantly inhibited, but when heated above 80°C, the complex decomposes or undergoes a structural change, releasing the catalytic active species and causing the urethane reaction between the isocyanate and the polyol to proceed rapidly.

[0075] For the thermostatic catalyst of the present invention, it is preferable to use a delayed catalyst which is a complex composed of 1,8-diazabicyclo[5.4.0]undecane-7-ene, which is DBU, and octanoate.

[0077] The technical reasons why a thermostatic catalyst and a non-expanding thermally expansive hollow filler must be used together are described below.

[0078] When using conventional general curing catalysts such as bismuth-based catalysts instead of thermochromic catalysts, the urethane reaction starts immediately after mixing the main component and the curing agent, and gelation proceeds within minutes.

[0079] In this state, for the non-expandable thermally expandable hollow filler to expand, it must be heated to 80 to 100°C. However, after the coating layer has already gelled or solidified, the expansion of the hollow filler does not form an embossed protrusion (710) structure on the surface of the coating layer (700) and only results in localized stress within the coating layer.

[0080] On the other hand, when using a thermochromic catalyst as in the present invention, fluidity is maintained at room temperature for more than 1 hour even after mixing the main component and the curing agent, allowing sufficient application to the back surface of the sheet (100) with a coating roller (410) or a flat knife, and subsequently, when heating to 80 to 120°C is performed in a heating chamber (500), the activation of the thermochromic catalyst and the expansion of the hollow filler occur simultaneously, and embossing protrusions (710) with a height of 2 to 5 mm are uniformly formed on the surface of the coating layer (700).

[0081] In other words, the combination of a thermostatic catalyst and a non-expanding thermally expansive hollow filler produces a technical synergy that cannot be achieved by either one alone.

[0083] The above-mentioned amine for the chain extender is a component that controls the mechanical strength and curing speed of the coating layer (700) by rapidly reacting with the isocyanate during the curing reaction to form a urea bond.

[0084] Examples of amines for chain extenders that can be used in the present invention include 1-methyl-3,5-diethyl-2,4-diaminobenzene or 1-methyl-3,5-diethyl-2,6-diaminobenzene, also called diethyltoluene diamine, and mixtures of their isomers, aromatic diamines containing dimethylthio substituents, 4,4-methylenebis(2-isopropyl-6-methylaniline), and 4,4-methylenebis(2,6-diisopropylaniline), and these may be used alone or in combination.

[0086] The above polyether polyol serves as a major matrix component of the curing agent composition and provides flexibility and elasticity to the final coating layer (700).

[0087] In the present invention, the amount of other components used is determined based on 100 parts by weight of the polyether polyol as a standard component of the curing agent composition.

[0088] If the polyether polyol is contained in excessive amounts, the hardness of the coating layer becomes excessively low, causing stickiness, and thus the pile yarn (110) sticks to the surface of the coating layer (700) during the final process of winding the artificial turf into a roll. Therefore, an appropriate content must be determined by considering the balance with other components.

[0090] The above polybutadiene polyol is a component that imparts excellent elastic recovery and hydrophobicity to the coating layer (700), and provides fixing power so that the coating layer (700) does not slip even in a wet environment when the artificial turf is installed on a concrete floor surface.

[0091] The polybutadiene polyol used in the present invention preferably has a Cis-1,4 polybutadiene content of 80% or more and a weight-average molecular weight of 2,000 to 5,000.

[0092] The elastic recovery power is excellent when the Cis-1,4 structure is 80% or more, and if the weight-average molecular weight is less than 2,000, the durability of the coating layer (700) is reduced, and if it exceeds 5,000, the viscosity becomes excessively high, making it difficult to manufacture and mix the curing agent composition.

[0094] Polybutadiene polyol is a rubber-like elastomer containing multiple double bonds in its molecular structure, and by imparting viscoelasticity to the coating layer (700) after curing, it exhibits a significantly higher surface friction coefficient compared to general SBR latex, general polyurethane, polyethylene, and polyethylene terephthalate-based coating materials.

[0095] As a result, even if thermal expansion and contraction occur due to repeated movement and changes in direction by players, as well as temperature fluctuations, after the artificial turf is installed on the sports field surface, it is possible to fundamentally prevent slipping and wrinkling phenomena, such as the entire artificial turf sliding along the surface or lifting up locally.

[0096] Furthermore, the high frictional fixation achieved by polybutadiene polyol enables the stable fixation of artificial turf without the use of separate floor adhesives during installation, thereby enhancing installation convenience and imparting eco-friendly characteristics that suppress the generation of harmful chemicals.

[0097] In addition, even when artificial turf needs to be replaced or removed at the construction site, it can be cleanly detached without adhesive residue or damage to the floor surface, contributing to reduced maintenance costs.

[0098] In addition, the unique high elasticity and wear resistance of polybutadiene polyol effectively suppresses the peeling phenomenon occurring at the interface between the coating layer (700) and the sheet (100) even when repeated loads and ground friction accumulate after artificial turf installation.

[0099] Therefore, the tensile strength of the pile yarn (110) is maintained for a long period and the structural completeness of the coating layer (700) is preserved, thereby extending the lifespan of the entire artificial turf, extending the replacement cycle, and significantly reducing maintenance costs.

[0101] The present invention is applicable to the above-described embodiments, and is also applicable to various embodiments as follows.

[0103] First, in the present invention, the main component / hardener index, which is the mixing ratio of the main component and the hardener composition, is an important variable that determines the hardness and shock absorption of the final coating layer (700).

[0104] The weight ratio of the main component / hardener index is preferably 0.9:1 to 1.5:1. If it is less than 0.9:1, a curing failure occurs and stickiness remains on the surface of the coating layer (700), and if it exceeds 1.5:1, the hardness of the coating layer (700) increases excessively and shock absorption is reduced.

[0105] More preferably, mixing in a weight ratio of 1:1 to 1.3:1 can best achieve a balance of shock absorption and mechanical strength.

[0107] Meanwhile, it is preferable that the back coating composition according to the present invention be applied to the rear surface of a sheet (100) that has been transported by inverting the pile yarn (110) so that it faces downward.

[0108] In the conventional spray method, the coating material is sprayed with the pile fibers (110) facing upward, but in the present invention, the sheet (100) is inverted so that the pile fibers (110) face downward, thereby preventing the coating material from unnecessarily penetrating between the pile fibers (110) due to gravity, so that the coating layer (700) can be formed with a uniform thickness.

[0110] Meanwhile, the artificial turf having a coating layer (700) formed from a back coating agent composition according to the present invention has a tensile strength of 80 N or more and an impact absorption capacity of 20% or more according to the KS F 3888-1 test method, and an embossing protrusion (710) with a height of 2 to 5 mm is formed on the back surface of the coating layer (700).

[0111] This embossing protrusion (710) is formed by a non-expanding thermally expandable hollow filler expanding in a heating chamber (500) and pushing up the surface of the coating layer (700), thereby improving shock absorption through a mechanism that absorbs external impact energy by deforming the protrusion structure.

[0112] If the height of the embossing protrusion (710) is less than 2mm, the effect of improving shock absorption is insufficient, and if it exceeds 5mm, the mechanical stability of the coating layer (700) is reduced, and there is a risk that the protrusion may be damaged during use.

[0114] Hereinafter, a manufacturing apparatus and a manufacturing method using an artificial turf back coating composition according to the present invention will be described in detail with reference to FIGS. 1 to 3.

[0116] As illustrated in FIG. 1, the artificial turf manufacturing device according to the present invention includes a conveyor (200), a coating means (400), a heating chamber (500), and a perforating means (600), and these are arranged sequentially so that a sheet (100) is transported in one direction and a continuous manufacturing process is performed.

[0118] The above conveyor (200) serves to transport the sheet (100) with the pile yarn (110) tufted in one direction in an inverted state so that the pile yarn (110) faces downward.

[0119] By supplying the sheet (100) in an inverted manner, the coating agent is applied only to the rear surface of the sheet (100) by the coating means (400) described later, thereby preventing unnecessary inflow of the coating agent toward the pile yarn (110).

[0121] The above coating means (400) is configured to apply an artificial turf back coating composition according to the present invention to the rear surface of an inverted sheet (100).

[0122] The coating means (400) may include a coating roller (410) that rotates in contact with the rear surface of the sheet (100), or a flat knife that evenly coats the coating agent onto the rear surface of the sheet (100).

[0123] The coating roller (410) method is suitable for continuous processes and has excellent uniformity of coating thickness, while the flat knife method is suitable for small-scale production due to its simple structure.

[0124] The back coating composition according to the present invention maintains fluidity for more than 1 hour by suppressing the curing reaction by a thermochromic catalyst at room temperature, so sufficient working time is secured regardless of whether a roller method or a flat knife method is selected. It is preferable to have a coating thickness of 1 to 5 mm.

[0126] In the manufacturing apparatus of the present invention, a perforating drum (300) that forms a plurality of through holes in the sheet (100) may be further provided between the conveyor (200) and the coating means (400).

[0127] On the outer surface of the perforation drum (300), perforation pins (310) are arranged in multiple rows and columns, so that as the sheet (100) passes between the perforation drum (300) and the conveyor (200), multiple through holes are formed through the rear surface of the sheet (100).

[0128] This through hole allows the subsequently applied coating agent to penetrate the sheet (100) through the through hole and wrap around the lower part of the pile yarn (110), thereby exhibiting the effect of further improving the pulling force.

[0130] The heating chamber (500) is configured to heat the sheet (100) coated with a coating agent to a temperature of 80 to 120°C while passing it through.

[0131] Two phenomena occur simultaneously due to heating inside the heating chamber (500).

[0132] First, the thermochromic catalyst causes the decomposition or structural change of the DBU and octanoate complex at a temperature of 80°C or higher, releasing catalytic active species, and the urethane reaction between the isocyanate and the polyol proceeds rapidly, resulting in initial gelation within 15 to 30 seconds.

[0133] Secondly, when the non-expanding thermally expandable hollow filler reaches an expansion temperature of 80 to 100°C, the thermoplastic polymer shell softens and its volume increases due to the expansion of the internal gas, and as a result, an embossing protrusion (710) with a height of 2 to 5 mm is formed on the surface of the coating layer (700).

[0134] The simultaneous occurrence of these two phenomena is the core operating principle of the present invention, because the thermostatic catalyst must suppress the curing reaction until the heating point for the hollow filler to expand freely within the coating layer.

[0135] It is preferable that the heating temperature of the heating chamber (500) be 90 to 110°C and the heating time be 2 to 10 minutes. If the heating temperature is less than 80°C, the thermogenic catalyst is not sufficiently activated, and a curing failure occurs. If the temperature exceeds 120°C, there is a risk that the pile yarn (110) will be damaged by heat.

[0137] The above perforation means (600) is configured to form a drainage hole (720) in a sheet (100) on which a coating layer (700) is formed by passing through a heating chamber (500).

[0138] The drainage hole (720) allows rainwater to be drained smoothly during use of the artificial turf, thereby preventing water from accumulating on the surface of the artificial turf.

[0139] The perforation means (600) forms a drainage hole (720) after the coating layer (700) is completely cured, so it does not affect the structural completeness of the coating layer (700).

[0141] Hereinafter, a method for manufacturing artificial turf according to the present invention is described.

[0143] The method for manufacturing artificial turf according to the present invention comprises: a first step of inverting a sheet (100) in which pile yarns (110) are tufted so that the pile yarns (110) face downward and transporting it in one direction by means of a conveyor (200); a second step of applying a back coating agent composition according to the present invention to the back surface of the inverted sheet (100) using an application means (400); a third step of passing the sheet (100) coated with the back coating agent composition through a heating chamber (500) and heating it to 80 to 120°C to activate a thermochromic catalyst and simultaneously expand a non-expanding thermally expandable hollow filler to form a coating layer (700) and an embossing protrusion (710); and a fourth step of forming a drainage hole (720) in the sheet (100) with the coating layer (700) formed using a perforation means (600).

[0145] Additionally, prior to the second step, the method may further include a step of forming a plurality of through holes through the sheet (100) from the rear surface of the sheet (100) using a perforating drum (300) on which perforating pins (310) are arranged on the outer surface.

[0146] This pretreatment perforation step allows the coating agent to wrap around the bottom of the pile yarn (110) through the perforations, thereby producing the effect of further improving the pulling force.

[0148] Hereinafter, examples of the preparation of the main component and curing agent of the artificial turf back coating composition according to the present invention are described.

[0150] [Preparation of Main Composition] The compositional components as shown in Table 1 below were mixed in the specified amounts, and then the temperature was increased to prepare the main compositions 1 to 3, which are urethane prepolymers.

[0151] Composition of the subject composition (Unit: weight%) Composition Subject Composition 1 Subject Composition 2 Subject Composition 3 MDI-based isocyanate 1 80 60 50 MDI-based isocyanate 2 20 40 - MDI-based isocyanate 3 - - 50 Polyether polyol 40 40 38 NCO(%) 12 12 13

[0152] [Preparation of Curing Agent Composition] Curing agent compositions 1 to 3 were prepared by uniformly mixing the compositional components shown in Table 2 below using a mixer in the specified amounts.

[0153] Composition of the curing agent composition (Unit: weight%) Composition Curing agent composition 1 Curing agent composition 2 Curing agent composition 3 Non-expanding thermally expansive hollow filler 2 3 3 Thermosensitive catalyst 3 2 3 Amines for chain extenders 15 13 10 Polyether polyol 67 66 70 Polybutadiene polyol 13 16 14

[0154] The non-expanding thermally expandable hollow filler used in the curing agent composition was Nouryon’s Expancel 031 DU 40, the thermosensitive catalyst was SAN-APRO’s U-Cat SA102, the chain extender amine was Albemarle’s Ethacure 100, the polyether polyol was KPX’s SC-2204, and the polybutadiene polyol was Samyang Fine Chemical’s 45HT.

[0156] [Examples 1 to 9] Artificial turf back coating compositions of Examples 1 to 9 were prepared by combining the main compositions 1 to 3 and the curing agent compositions 1 to 3, respectively, as shown in Table 3 below.

[0157] Example Combination Matrix Curing agent composition 1 Curing agent composition 2 Curing agent composition 3 Subject Composition 1 Example 1 Example 2 Example 3 Subject Composition 2 Example 4 Example 5 Example 6 Subject Composition 3 Example 7 Example 8 Example 9

[0158] [Comparative Examples 1 to 3] Comparative examples were prepared under conditions where a bismuth-based catalyst was used instead of a thermochromic catalyst in the curing agent composition, and already expanded hollow fillers were used instead of non-expanding thermally expandable hollow fillers, or no hollow fillers were used at all.

[0159] Composition of Comparative Example Curing Agent Composition (Unit: weight%) Composition Comparative Curing Agent 1 Comparative Curing Agent 2 Comparative Curing Agent 3 Inflatable hollow filler or none 0 5 3 Bismuth-based catalysts 3 3 3 Amines for chain extenders 15 13 10 Polyether polyol 67 63 70 Polybutadiene polyol 15 16 14

[0160] The expansive hollow filler used in the comparative example was Nouryon’s Expancel 920 product, and the bismuth-based catalyst was ES CAT B-900D product.

[0162] Test specimens were prepared by applying the artificial turf back-coating compositions prepared in Examples 1 to 9 and Comparative Examples 1 to 3 to an average thickness of 2 mm on each uncoated artificial turf measuring 1 m x 1 m.

[0163] Tensile strength and elongation were measured using test specimens made in a separate mold according to the KS F 3211 test method, and shock absorption and pull-out strength were measured by applying directly to artificial turf according to the KS F 3888-1 test method.

[0164] Hardness was measured according to the KS M 6518 test method.

[0165] Physical property test results Tensile strength (MPa) Growth rate (%) Hardness (Shore A) Pulling force (N) Shock absorption (%) Example 1 8.2 270 82 110 28 Example 2 7.1 230 80 98 30 Example 3 5.6 180 75 95 32 Example 4 9.4 310 84 110 28 Example 5 7.8 250 81 99 30 Example 6 6.6 210 79 96 31 Example 7 9.3 300 84 120 26 Example 8 7.3 240 80 100 25 Example 9 6.4 200 78 99 25 Comparative Example 1 17.8 420 90 55 15 Comparative Example 2 7.8 260 80 60 19 Comparative Example 3 6.6 220 79 58 17

[0166] As shown in Table 5, Examples 1 to 9, which used a thermochromic catalyst and a non-expanding thermally expansive hollow filler together, significantly exceeded the tensile strength requirement of 0.6 MPa or more according to the KS F 3888-2 multi-purpose standard with a minimum of 5.6 to 9.4 MPa, and also satisfied the elongation rate requirement of 60% or more with 180 to 310%.

[0167] In particular, the tensile strength showed results of 95 to 120 N, which meets the standard value of 80 N or more of KS F 3888-1, and the shock absorption also recorded a value of 25 to 32%, which meets the standard value of 20% or more.

[0168] On the other hand, Comparative Examples 1 to 3, which used a bismuth-based catalyst instead of a thermochromic catalyst and were manufactured with or without an expansive hollow filler, had a tensile strength of 55 to 60 N, which fell short of the standard value, and the shock absorption was also 15 to 19%, which did not meet the standard value.

[0169] This is analyzed to be because, when using a general curing catalyst, the initial curing speed is fast, so curing is completed before the expansion effect of the hollow filler is fully manifested, resulting in a failure to achieve the required tensile strength and shock absorption.

[0171] As described above, the basic technical concept of the present invention is to provide an artificial turf back coating composition and a method for manufacturing artificial turf using the same, wherein the composition comprises a main component containing an isocyanate prepolymer and a curing agent composition containing a thermochromic catalyst and a non-expanding thermally expandable hollow filler, and wherein at room temperature, the urethane curing reaction is suppressed by the thermochromic catalyst, thereby ensuring sufficient working time and enabling the coating agent to be directly applied to the back of the sheet using a roller or a flat knife.

[0172] And, it goes without saying that many other variations and applications are also possible for those skilled in the art within the scope of the basic technical concept of the present invention. Explanation of the symbols

[0174] 100...sheet 110...Filesa 200...conveyor 300...Perforation Drum 310...perforation pin 400... coating means 410...Coating roller 500...heating chamber 600...perforation means 700...coating layer 710...embossing protrusions 720...drainage hole

Claims

Claim 1 An artificial turf backcoating composition comprising: a main component comprising a methylene diphenyl isocyanate (MDI)-based urethane prepolymer; and a thermochromic catalyst comprising a composite of DBU (1,8-diazabicyclo[5.4.0]undecane-7-ene) and octanoate, which inhibits urethane reaction at room temperature and releases catalytic active species under heating conditions of 80 to 120°C, and a non-expanding thermally expandable hollow filler having an average particle diameter of 10 to 16 μm and an expansion temperature of 80 to 100°C; wherein the main component and the curing composition are mixed. Claim 2 An artificial turf back coating composition according to claim 1, wherein the curing agent composition comprises a polyether polyol, and further comprises, with respect to 100 parts by weight of the polyether polyol, 1 to 9 parts by weight of the non-expanding thermally expandable hollow filler, 0.1 to 5 parts by weight of the thermosensitive catalyst, 12 to 34 parts by weight of the amine for chain extending, and 12 to 34 parts by weight of the polybutadiene polyol. Claim 3 An artificial turf back coating composition according to claim 1, wherein the non-expandable thermally expandable hollow filler contains a hydrocarbon gas inside and is surrounded on the outside by a thermoplastic polymer shell. Claim 4 delete Claim 5 An artificial turf back coating composition according to claim 1, characterized in that the main component has an NCO content of 10 to 18%, and the mixing ratio (main component / curing agent index) of the main component and the curing agent composition is a weight ratio of 0.9:1 to 1.5:

1. Claim 6 An artificial turf back coating composition according to claim 2, wherein the polybutadiene polyol has a Cis-1,4 polybutadiene content of 80% or more and a weight-average molecular weight of 2,000 to 5,000. Claim 7 Artificial turf having a coating layer formed of a back coating agent composition according to claim 1, wherein the coating layer has a tensile strength of 80 N or more and an impact absorption capacity of 20% or more according to the KS F 3888-1 test method, and is characterized by having embossed protrusions with a height of 2 to 5 mm formed on the rear surface of the coating layer.

Images