Composition for coating protective film

Abstract

The present invention relates to a composition for a paint protective film comprising an acrylic emulsion resin, a polyurethane dispersion, and a polyolefin resin, wherein the acrylic emulsion resin has a weight-average molecular weight of 200,000 to 300,000 g / mol and a glass transition temperature of 50 to 80°C, and the polyurethane dispersion has a weight-average molecular weight of 40,000 to 60,000 g / mol and a glass transition temperature of -70 to -20°C.

Description

[Technical Field]

[0001] The present invention relates to a paint protective film composition that temporarily protects the painted surface of an automobile or heavy equipment, etc., and is easily peelable. [Background technology]

[0002] The present invention relates to a paint protective film composition that protects the painted surface of automobiles or heavy equipment during temporary storage and that is easily peelable.

[0003] When automobiles or heavy equipment are temporarily stored outdoors before being delivered to the end user, or during transportation, there is a high possibility that the painted surface may become damaged, uneven, discolored, or stained due to exposure to contaminants such as dust, iron, salts, alkalis, acids, soot, dead insects, and body fluids, as well as sunlight, wind, rain, and other influences.

[0004] Additionally, physical forces may cause external damage to the material.

[0005] Therefore, in order to temporarily protect the surfaces of automobiles or heavy equipment from contaminants, sunlight, wind, rain, external damage, etc., many peelable coating compositions have been proposed that are applied to the surface in advance at the time of product shipment and can be easily peeled off after a certain period of storage.

[0006] However, conventional coating compositions require the use of petroleum-based solvents when they are removed, which poses environmental problems such as air pollution.

[0007] Furthermore, compositions containing alkali-soluble resins as their main component have also been used, but these require the use of alkaline detergents for removal, which poses problems of environmental pollution, such as water pollution.

[0008] Therefore, in order to protect the coating surfaces of automobiles or heavy equipment, etc., there is a need to develop a composition for a paint protection film that is easy to peel off and has excellent adhesive strength. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Republic of Korea Patent No. 10-0498717 (2005.06.22.) Summary of the Invention [Problem to be solved by the invention]

[0010] In one aspect, the present invention provides a composition for a paint protection film that is easy to peel and has excellent adhesive strength in order to protect the coated surface of an automobile or heavy equipment.

[0011] In yet another aspect, the present invention provides a paint protection film produced from a paint protection film composition that is easy to peel and has excellent adhesion, in order to protect the coated surface of an automobile or heavy equipment, etc. [Means for solving the problem]

[0012] In one aspect, the present invention can provide a composition for a coating protective film comprising an acrylic emulsion resin, a polyurethane dispersion, and a polyolefin resin, wherein the acrylic emulsion resin has a weight-average molecular weight of 200,000 to 300,000 g / mol and a glass transition temperature of 50 to 80°C, and the polyurethane dispersion has a weight-average molecular weight of 40,000 to 60,000 g / mol and a glass transition temperature of -70 to -20°C.

[0013] In yet another aspect, the present invention provides a paint protective film produced by curing the composition for a paint protective film according to the present invention. [Effects of the Invention]

[0014] The composition for a coating protective film according to one aspect of the present invention is characterized by its fast drying speed, excellent initial adhesion and excellent adhesion retention, and the ability to cleanly remove coating films without leaving any residue after removal. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will be described in more detail below with reference to embodiments.

[0016] In one aspect, the present invention provides a composition for a paint protection film that does not react with the vehicle body paint film, is easy to peel off, and has excellent adhesive strength in order to protect the coated surface of an automobile or heavy equipment.

[0017] One embodiment of the present invention provides a composition for a paint protective film, which comprises an acrylic emulsion resin, a polyurethane dispersion, and a polyolefin resin, wherein the acrylic emulsion resin has a weight-average molecular weight of 200,000 to 300,000 g / mol and a glass transition temperature of 50 to 80°C, and the polyurethane dispersion has a weight-average molecular weight of 40,000 to 60,000 g / mol and a glass transition temperature of -70 to -20°C.

[0018] As described above, when an acrylic emulsion resin and a polyurethane dispersion having a weight-average molecular weight and a glass transition temperature within a specific range are used, the drying speed and crosslink density of the coating film can be adjusted, and not only the appearance characteristics of the coating film but also mechanical properties such as water resistance and solvent resistance can be improved. The surface tension of the composition can be adjusted, and the coating film can be protected by having appropriate adhesion without reacting with the vehicle body coating.

[0019] The composition for a coating protective film of the present invention may further include one or more additives selected from the group consisting of a neutralizing agent, a solvent, a dispersant, a leveling agent, an antifoaming agent, a UV stabilizer, a pigment, a thickener, and a preservative.

[0020] The above components will be specifically described below.

[0021] <Acrylic emulsion resin>

[0022] The acrylic emulsion resin improves the storage stability and water resistance of the composition for a paint protection film, and ensures the strength and adhesiveness of the paint protection film produced from the composition.

[0023] The acrylic emulsion resin may be synthesized by a known method or may be a commercially available product. For example, the acrylic emulsion resin may contain units derived from one or more monomers selected from the group consisting of allyl methacrylate (AMA), methyl methacrylate (MMA), ethyl acrylate (EA), ethyl methacrylate (EMA), hydroethyl acrylate (HEA), and methacrylic acid (MAA). As another example, the acrylic emulsion resin may be prepared from a mixture containing allyl methacrylate (AMA), methyl methacrylate (MMA), ethyl acrylate (EA), ethyl methacrylate (EMA), hydroethyl acrylate (HEA), and methacrylic acid (MAA) as monomers.

[0024] The mixture may further include a divalent acrylic monomer. Examples of the divalent acrylic monomer include 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,5-pentanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol dimethacrylate, ethylene glycol diacrylate, and ethylene glycol dimethacrylate.

[0025] The acrylic emulsion resin may have a viscosity of 30 to 100 cps or 50 to 80 cps at 25°C. When the viscosity of the acrylic emulsion resin at 25°C is within this range, the viscosity of the composition for a coating protective film is appropriate, resulting in improved workability. When the viscosity of the acrylic emulsion resin at 25°C is below this range, the viscosity of the composition is too low, and the resulting coating film may not be formed, resulting in problems such as reduced flow, adhesion, and scratch resistance. When the viscosity is above this range, the workability of the composition may be insufficient, resulting in problems such as reduced appearance of the resulting coating film.

[0026] The acrylic emulsion resin may have a pH of 5 to 9 or 6 to 8. When the pH of the acrylic emulsion resin is within this range, the viscosity of the composition for a coating protective film is appropriate, resulting in improved workability and storage stability. When the pH of the acrylic emulsion resin is below this range, the viscosity of the composition is too low, and the resulting coating film is not formed, resulting in problems such as reduced flow, adhesion, and scratch resistance. When the pH is above this range, the workability of the composition is insufficient, resulting in problems such as reduced appearance of the resulting coating film.

[0027] The acrylic emulsion resin may have an acid value (Av) of 3 to 6 mgKOH / g, or 3.5 to 5.5 mgKOH / g. When the acid value of the acrylic emulsion resin is within this range, the reactivity of a composition containing the acrylic emulsion resin can be adjusted, and the appearance characteristics of a coating film produced therefrom can be improved. When the acid value of the acrylic emulsion resin is below this range, problems such as reduced resin stability and reduced storage life of the produced coating composition can arise. When the acid value is above this range, problems such as increased viscosity of the composition due to increased resin cohesion can arise, resulting in reduced workability and water resistance of the coating film.

[0028] The acrylic emulsion resin may have a weight-average molecular weight (Mw) of 200,000 to 300,000 g / mol, or 220,000 to 280,000 g / mol. When the weight-average molecular weight of the acrylic emulsion resin is within this range, the resulting coating film can exhibit excellent long-term properties, such as durability, adhesion, hardness, and weather resistance. When the weight-average molecular weight of the acrylic emulsion resin is below this range, the molecular weight is small, and the resulting coating film can exhibit insufficient water resistance, weather resistance, and scratch resistance. When the weight-average molecular weight of the acrylic emulsion resin is above this range, the increased molecular weight can result in reduced flowability, which can lead to poor workability of a coating protective film composition containing the resin, poor surface smoothness, and difficulty in producing a coating film with excellent appearance.

[0029] The acrylic emulsion resin may have a glass transition temperature (Tg) of 50 to 80°C, or 60 to 70°C. When the glass transition temperature of the acrylic emulsion resin is within this range, it has the effect of maintaining appropriate adhesion without reacting with the vehicle body paint film and improving the hardness and solvent resistance of the paint film. When the glass transition temperature of the acrylic emulsion resin is below this range, the drying speed and crosslink density of the paint film may decrease, and the hardness and solvent resistance of the produced paint film may be insufficient. When the glass transition temperature is above this range, the paint film may become brittle, and the appearance properties and chipping resistance of the produced paint film may be insufficient.

[0030] Furthermore, the acrylic emulsion resin may be in the form of an emulsion dispersed in deionized water. For example, the acrylic emulsion may be in the form of an emulsion dispersed in deionized water and have an average diameter of 150 to 300 nm or 180 to 260 nm. When the acrylic emulsion resin is in the form of an emulsion dispersed in deionized water, it has the effect of reducing the volatile organic compounds (VOC) content of the paint, and when the average diameter is within the above range, it has good appearance and particle stability.

[0031] The acrylic emulsion resin can be included in the composition in an amount of 30 to 50 wt % or 35 to 45 wt % based on the total weight of the composition for a coating protective film. When the acrylic emulsion resin is included in this range, it is effective in improving the adhesion, durability, hardness, and scratch resistance of the coating film. If the acrylic emulsion resin content is less than this range, the drying speed may be reduced, resulting in problems such as reduced adhesion, gloss, hardness, and durability of the coating film. If the acrylic emulsion resin content is more than this range, the drying speed may be accelerated, resulting in poor coating workability and flow properties of the composition, reduced coating appearance and scratch resistance, and increased residue after coating removal.

[0032] <Polyurethane dispersion>

[0033] The polyurethane dispersion used in the composition for a paint protective film of the present invention serves to improve the adhesiveness, flexibility and tensile strength of the composition.

[0034] The polyurethane dispersion may be prepared by reacting a polyol, a diisocyanate, and an acid, wherein the polyol may be at least one selected from the group consisting of 1,6-hexanediol, ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, trimethylolpropane, butanediol, 1,4-hexanediol, and 3-methylpentanediol, and the diisocyanate may be isophorone diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, propylene diisocyanate, ethylene diisocyanate, 2,3-dimethylethylene diisocyanate, or 2,3-dimethylethylene diisocyanate. The isocyanate may be one or more selected from the group consisting of ethylene diisocyanate, 1-methyltrimethylene diisocyanate, 1,3-cyclopentene diisocyanate, 1,4-cyclopentene diisocyanate, 1,2-cyclopentene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, oligomeric isocyanate, isophorone diisocyanate, 4,4-diphenylpropane diisocyanate, xylene diisocyanate, and 1,1,6,6-tetramethylhexamethylene diisocyanate. The acid may be at least one selected from the group consisting of adipic acid, dimethylolpropionic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, adipic acid, fumaric acid, maleic acid, trimellitic acid, malic acid, sulfonic acid, and aconitic acid. Meanwhile, the polyurethane dispersion is in a form in which a polyurethane resin is dispersed in a solvent, and for example, the polyurethane dispersion may be a dispersion in deionized water.

[0035] On the other hand, the aqueous medium in which the polyurethane resin is dispersed may be a water-based solvent or a mixed medium of water and a hydrophilic organic solvent. For example, the water-based solvent may be tap water, ion-exchanged water, distilled water, ultrapure water, etc. In particular, ion-exchanged water can be used because of its ease of availability and to prevent particles from becoming unstable due to the influence of salts. In addition, the hydrophilic organic solvent may be a lower monohydric alcohol such as methanol, ethanol, or propanol, a polyhydric alcohol such as ethylene glycol or glycerin, or an aprotic hydrophilic organic solvent such as N-methylmorpholine, dimethyl sulfoxide, or dimethylformamide.

[0036] The polyurethane dispersion may have a solids content (NV) of 30 to 50 wt %, or 35 to 45 wt %, based on the total weight of the dispersion. When the solids content of the polyurethane dispersion is within this range, the storage stability of the resin and the storage stability of the composition for a coating protective film are improved, resulting in excellent workability. If the solids content of the polyurethane dispersion is below this range, the viscosity may be too low, resulting in insufficient workability of the composition for a coating protective film containing the polyurethane dispersion. If the solids content exceeds this range, the viscosity of the polyurethane dispersion may be too high, resulting in reduced stability during the reaction, poor dispersion stability, and possible aggregation over time.

[0037] The viscosity of the polyurethane dispersion at 25°C may be 10 to 300 cps, or 20 to 250 cps. When the viscosity of the polyurethane dispersion at 25°C is within this range, the viscosity of the composition for a coating protective film is appropriate, and workability is improved. When the viscosity of the polyurethane dispersion at 25°C is below this range, the viscosity of the composition is too low, which can lead to problems such as under-formation of the coating film, resulting in reduced flow, adhesion, and scratch resistance. When the viscosity is above this range, the workability of the composition is insufficient, which can lead to problems such as reduced appearance of the coating film produced.

[0038] The polyurethane dispersion may have a pH of 6 to 8, or 6.3 to 7.7. When the pH of the polyurethane dispersion is within this range, the viscosity of the composition for a coating protective film is appropriate, which has the effect of improving workability. When the pH of the polyurethane dispersion is below this range, the viscosity of the composition is too low, which can cause problems such as under-formation of the produced coating film, resulting in reduced flow, adhesion, and scratch resistance. When the pH is above this range, the workability of the composition is insufficient, which can cause problems such as reduced appearance of the produced coating film.

[0039] The polyurethane dispersion may have a weight-average molecular weight (Mw) of 40,000 to 60,000 g / mol, or 45,000 to 55,000 g / mol. When the weight-average molecular weight of the polyurethane dispersion is within this range, the composition for a paint protective film has improved smoothness and forms a soft coating, improving adhesion to the vehicle paint and abrasion resistance. When the weight-average molecular weight of the polyurethane dispersion is below this range, the molecular weight is too small, resulting in poor mechanical properties of the resulting coating. When the weight-average molecular weight is above this range, the increased molecular weight can reduce flow, causing the coating to become brittle, resulting in poor smoothness and poor scratch resistance.

[0040] The polyurethane dispersion may have a glass transition temperature (Tg) of -70 to -20°C, or -60 to -30°C. When the glass transition temperature of the polyurethane dispersion is within this range, the flexibility and hardness of the coating film are improved. When the glass transition temperature of the polyurethane dispersion is below this range, the drying rate of the composition for a coating protective film is slowed and the resulting coating film may have insufficient solvent resistance and chipping resistance. When the glass transition temperature is above this range, the coating film may become brittle and the appearance and hardness of the coating film may be insufficient.

[0041] The polyurethane dispersion may be included in the composition in an amount of 20 to 30 wt % or 22 to 28 wt % based on the total weight of the composition for a coating protective film. When the polyurethane dispersion is included in this range, it is effective in improving tensile strength, flexibility, elongation, adhesion, abrasion resistance, scratch resistance, and coating smoothness. If the polyurethane dispersion content in the composition is less than this range, problems such as reduced flexibility, tensile strength, and scratch resistance may occur. If the polyurethane dispersion content exceeds this range, the viscosity of the composition may become too high, resulting in problems such as reduced workability and drying speed, and reduced appearance and mechanical properties.

[0042] <Polyolefin resin>

[0043] The polyolefin resin increases the surface tension of the paint protection film composition, providing suitable adhesion to the vehicle body paint and excellent removability that allows the coating film to be cleanly removed without reacting with the vehicle body paint.

[0044] Examples of polyolefin resins that can be used include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ethylene-propylene copolymer, metallocene-polyethylene, polypropylene homopolymer, polypropylene copolymer, metallocene-polypropylene, and physical property-reinforced composite resins of polypropylene homopolymer and copolymer.

[0045] On the other hand, the polyolefin resin may be, for example, halogenated or modified to contain a carboxyl group, and preferably polyethylene, polypropylene, polybutadiene, polyisoprene, polystyrene, or a copolymer of any two or more of these. The polyolefin resin may be further modified to a resin such as a maleic acid resin. In one specific example, the (modified) polyolefin may be one or more selected from halogenated polyolefin-maleic acid copolymers such as chlorinated polypropylene-maleic acid resin, polyolefin-maleic acid copolymers, styrene / ethylene-butylene, styrene / butadiene, styrene / ethylene-propylene, or styrene / isoprene copolymers. Suitable polyolefins are commercially available from Toyobo Co., Ltd. under the trade names Hardlen® RNZ-1004, Hardlen® RNZ-1015, Hardlen® REH-801J, and Hardlen® RCY-9124 / 9122, and from KRATON Performance Polymers Inc. under the trade names Kraton® RG1643E and Kraton® RG1640ES.

[0046] The polyolefin resin may have a solids content (NV) of 20 to 40 wt % or 25 to 35 wt % based on the total weight of the dispersion. When the solids content of the polyolefin resin is within this range, the storage stability of the resin and the storage stability of the composition for a paint protective film are improved, resulting in excellent workability. When the solids content of the polyolefin resin is below this range, the viscosity becomes too low, resulting in problems such as insufficient workability of the composition for a paint protective film containing the polyolefin resin. When the solids content exceeds this range, the viscosity of the polyolefin resin becomes too high, resulting in reduced stability during the reaction, poor dispersion stability, and possible aggregation over time.

[0047] The viscosity of the polyolefin resin at 25°C may be 10 to 250 cps, or 20 to 200 cps. When the viscosity of the polyolefin resin at 25°C is within this range, the viscosity of the composition for a coating protective film is appropriate, and workability is improved. When the viscosity of the polyolefin resin at 25°C is below this range, the viscosity of the composition is too low, and the resulting coating film is not formed, resulting in problems such as reduced flow, adhesion, and scratch resistance. When the viscosity is above this range, the workability of the composition is insufficient, resulting in problems such as reduced appearance of the resulting coating film.

[0048] The polyolefin resin may have a pH of 6 to 8, or 6.3 to 7.7. When the pH of the polyolefin resin is within this range, the viscosity of the composition for a coating protective film is appropriate, which has the effect of improving workability. When the pH of the polyolefin resin is below this range, the viscosity of the composition is too low, and the resulting coating film is not formed, resulting in problems such as reduced flow, adhesion, and scratch resistance. When the pH is above this range, the workability of the composition is insufficient, resulting in problems such as reduced appearance of the resulting coating film.

[0049] The polyolefin resin may have a weight-average molecular weight (Mw) of 70,000 to 90,000 g / mol, or 75,000 to 85,000 g / mol. When the weight-average molecular weight of the polyolefin resin is within this range, the composition for a paint film protection film has improved smoothness, forms a soft coating film, and has suitable adhesion to vehicle body paint films, improving scratch resistance and hardness. When the weight-average molecular weight of the polyolefin resin is below this range, the molecular weight is small, resulting in problems with the mechanical properties of the resulting coating film. When the weight-average molecular weight is above this range, problems arise such as reduced flow due to the increased molecular weight, resulting in brittle coatings, reduced smoothness and scratch resistance, and increased residue after removal of the coating film.

[0050] The polyolefin resin can be included in an amount of 25 to 40 wt % or 28 to 36 wt % based on the total weight of the composition for a coating protective film. When the polyolefin resin is included within this range, excellent adhesion is achieved, discoloration of pigments is prevented, excellent appearance is achieved, and appropriate releasability is maintained. When the polyolefin resin is included below this range, problems such as reduced adhesion and increased residue after coating removal can occur. When the polyolefin resin is included above this range, compatibility with other components and the physical properties of the composition for a coating protective film can be reduced.

[0051] The acrylic emulsion resin and the polyolefin resin can be mixed at a weight ratio of 1:0.7 to 1, for example, 1:0.75 to 0.95.

[0052] When the blend ratio of the acrylic emulsion resin and the polyolefin resin falls within the above-mentioned range, the composition maintains appropriate drying properties, has appropriate adhesion to the vehicle body paint film, and can cleanly remove the coating film without leaving any residue after desorption.

[0053] <Solvent>

[0054] The solvent is primarily water and may further contain an organic solvent. The aqueous solvent may be ion-exchanged water, distilled water, ultrapure water, or the like. The organic solvent is not particularly limited as long as it can improve storage stability, provide quick-drying properties, and act as a curing agent, and does not cause any problems in the production of the coating protective film composition. Examples of the organic solvent include alcohol-based solvents such as butyl cellosolve, butyl carbitol, n-propanol, isopropanol, n-butanol, isobutanol, and tert-butanol.

[0055] The solvent may be included in an amount of 0.5 to 5 wt % based on the total weight of the composition for a coating protective film. When used within this range, viscosity control may be easy, and the coating protective film using the composition for a coating protective film may have excellent smoothness and coating workability.

[0056] <Additives>

[0057] Additives may be added to the composition for a paint protection film within a predetermined content range to exert additional effects such as improving wetting and leveling during coating. For example, additives may include neutralizers, dispersants, leveling agents, antifoaming agents, UV stabilizers, pigments, thickeners, and preservatives.

[0058] The additives may be included in an amount of 1 to 3 wt % or 1.5 to 2.5 wt % based on the total weight of the composition for a coating protective film. When used within this range, the composition for a coating protective film can maintain excellent storage stability.

[0059] In yet another aspect, the present invention provides a paint protection film produced from a paint protection film composition that is easy to peel and has excellent adhesive strength, for protecting the coated surface of an automobile or heavy equipment, etc.

[0060] The coating protective film of the present invention can be produced by curing the coating protective film composition of the present invention.

[0061] Specifically, the composition for a paint protective film of the present invention can be applied to a substrate to a thickness of 10 to 100 μm using a method such as spraying, brushing, or roller, and then cured at room temperature, in an oven, or with an IR lamp to form a paint protective film.

[0062] The present invention will be described in more detail below through examples.

[0063] However, these examples are provided to aid in understanding the present invention and are not intended to limit the scope of the present invention in any way.

[0064] Example

[0065] Compositions for coating protective films were prepared by adding the resins according to the compositions shown in Tables 1 to 3 below, and then adding the solvent and additives in that order while stirring.

[0066] Comparative Example

[0067] Compositions for coating protective films were prepared by adding the resins according to the compositions shown in Tables 4 and 5 below, and then adding the solvent and additives in that order while stirring.

[0068] [Table 1(1)] [Table 1(2)]

[0069] [Table 2(1)] [Table 2(2)]

[0070] [Table 3(1)] [Table 3(2)]

[0071] [Table 4(1)] [Table 4(2)]

[0072] [Table 5(1)] [Table 5(2)]

[0073] The specific components used in the preparation of the compositions for paint protective films in Tables 1 to 5 are shown in Table 6 below.

[0074] [Table 6(1)] [Table 6(2)]

[0075] Experimental Example

[0076] The paint protection films produced using the compositions for paint protection films of the Examples and Comparative Examples, which were produced by mixing the compositions in Tables 1 to 5, were evaluated for physical properties using the methods described below, and the results are shown in Tables 7 and 8 below.

[0077] Painting method

[0078] The compositions prepared in each example and comparative example were sprayed onto a conductor coated with an automotive clear coat to a coating thickness of 30 μm, and then cured at 80° C. for 3 minutes to form a film.

[0079] Physical property evaluation

[0080] 1) Drying: The tack-free time was measured when a coated test piece was briefly touched with the index finger without any paint getting on it. If the tack-free time was between 2 and 7 minutes, it was evaluated as meeting the mechanical properties required for a coating protection film.

[0081] 2) Adhesion, residue: The coating composition was applied, dried at room temperature for 24 hours, and then left at 70°C for one week. After leaving it at room temperature for one hour, an Instron machine was used to test the adhesion and measure the residue. If the adhesion was between 0.4 kg / inch and 1.5 kg / inch, it was evaluated as meeting the adhesive strength for a paint protection film.

[0082] 3) Solvent resistance: 0.1 ml each of isopropyl alcohol, ethanol, and methyl ethyl ketone was applied to the surface of the coating layer, and after leaving it for 5 minutes, the solvent resistance was checked. If the coating layer surface did not change visually, it was rated as excellent (◎); if the coating layer surface swelled, cracked, tore, or changed color, it was rated as good (○), average (△), or poor (×).

[0083] 4) Water resistance: The completed coating film was submerged in a 40℃ thermostatic chamber for 10 days, and then an adhesion test and appearance evaluation were carried out. Excellent (◎) was given for no blisters or peeling, good (○) for no blisters and partial peeling along the scale lines, fair (△) for no blisters and peeling over 1 / 4 of the surface, and poor (×) for blisters or peeling over 1 / 4 of the surface.

[0084] [Table 7]

[0085] [Table 8]

[0086] The paint protection films produced using the compositions of the Examples all had excellent physical properties. Comparative Examples 1 to 4 and 6 to 10 had poor solvent resistance, and Comparative Examples 3 to 4, 6, 8, 10, and 11 had poor water resistance. Comparative Example 5 had excessive residual content.

[0087] Various embodiments of the present invention will now be described.

[0088] (1) A composition for a coating protective film comprising an acrylic emulsion resin, a polyurethane dispersion, and a polyolefin resin, wherein the acrylic emulsion resin has a weight-average molecular weight of 200,000 to 300,000 g / mol and a glass transition temperature of 50 to 80°C, and the polyurethane dispersion has a weight-average molecular weight of 40,000 to 60,000 g / mol and a glass transition temperature of -70 to -20°C.

[0089] (2) A composition for a coating protective film, wherein the acrylic emulsion resin has an acid value of 3 to 6 mgKOH / g and a viscosity at 25°C of 30 to 100 cps.

[0090] (3) A composition for a paint protective film, wherein the polyolefin resin has a weight average molecular weight of 70,000 to 90,000 g / mol and a viscosity at 25°C of 10 to 250 cps.

[0091] (4) A composition for a paint protective film, comprising 30 to 50% by weight of an acrylic emulsion resin, 20 to 30% by weight of a polyurethane dispersion, and 25 to 40% by weight of a polyolefin resin, based on the total weight of the composition for a paint protective film.

[0092] (5) A paint protection film produced by curing a paint protection film composition according to any one of items (1) to (4).

Claims

1. The composition includes an acrylic emulsion resin, a polyurethane dispersion, and a polyolefin resin, The acrylic emulsion resin has a weight average molecular weight of 200,000 to 300,000 g / mol and a glass transition temperature of 50 to 80°C; The polyurethane dispersion is a composition for use in a coating protective film, having a weight average molecular weight of 40,000 to 60,000 g / mol and a glass transition temperature of -70 to -20°C.

2. 2. The composition for use in a paint protective film according to claim 1, wherein the acrylic emulsion resin has an acid value of 3 to 6 mgKOH / g and a viscosity at 25° C. of 30 to 100 cps.

3. 2. The composition for use in a paint protective film according to claim 1, wherein the polyolefin resin has a weight average molecular weight of 70,000 to 90,000 g / mol and a viscosity at 25° C. of 10 to 250 cps.

4. 2. The composition for a paint protective film according to claim 1, comprising 30 to 50% by weight of an acrylic emulsion resin, 20 to 30% by weight of a polyurethane dispersion, and 25 to 40% by weight of a polyolefin resin, based on the total weight of the composition for a paint protective film.

5. A paint protective film produced by curing the composition for a paint protective film according to any one of claims 1 to 4.

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