Composition for coating protective film

Abstract

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

Description

Technical Field

[0001] The present invention relates to a coating protection film composition which is used for temporarily protecting the coating surface of automobiles, heavy equipment and the like and is easy to peel off. Background Art

[0002] The present invention relates to a coating protection film composition which protects the coating surface when temporarily storing automobiles or heavy equipment and is easy to peel off.

[0003] Automobiles or heavy equipment are temporarily stored outdoors until they are delivered to the final customer, or during transportation, there is a high possibility that the coating surface will be scratched, scarred, discolored, or contaminated due to pollutants such as sand, iron powder, salt, alkali, acid, coal ash, insect carcasses or body fluids, or the effects of sunlight, heavy rain, etc. In addition, the material may be scratched due to coercive force.

[0004] Therefore, in order to temporarily protect the surface of automobiles or heavy equipment from pollutants or damage by sunlight, heavy rain, scratches, etc., it is recommended to use a variety of peelable coating compositions, which can be pre-coated on the surface from the product release stage and easily peeled off after a certain period of storage.

[0005] However, when removing the conventional coating composition, a petroleum-based solvent is required, which causes environmental problems such as air pollution. In addition, a composition with an alkali-soluble resin as a main component is used, but when removing the composition, an alkaline detergent is used, which causes environmental pollution problems such as water pollution.

[0006] Therefore, in order to protect the painted surfaces of automobiles and heavy equipment, it is necessary to develop a composition for a paint protection film that is easy to peel and has good adhesion.

[0007]

Prior technical literature

[0008] [Patent Literature]

[0009] (Patent Document 1) Korean Patent Registration No. 10-0498717 (June 22, 2005) Summary of the invention

[0010] Issues to be solved

[0011] One aspect of the present invention provides a paint protection film composition that is easy to peel and has good adhesion to protect the painted surface of automobiles, heavy equipment, etc.

[0012] Another aspect of the present invention provides a coating protection film made of a coating protection film composition, which is easy to peel off and has good adhesion to protect the coating surface of automobiles or heavy equipment.

[0013] Problem Solution

[0014] One aspect of the present invention provides a composition for a coating protective film, which comprises an acrylic emulsion resin, a polyurethane dispersion and a polyolefin resin, wherein the weight average molecular weight of the acrylic emulsion resin is 200,000 to 300,000 g / mol, and the glass transition temperature is 50 to 80°C; the weight average molecular weight of the polyurethane dispersion is 40,000 to 60,000 g / mol, and the glass transition temperature is -70 to -20°C.

[0015] Another aspect of the present invention provides a coating protection film produced by curing the coating protection film composition of the present invention.

[0016] Effects of the Invention

[0017] The coating protective film composition described in one aspect of the present invention is characterized in that it has a fast drying speed, good initial adhesion and adhesion retention, and can be cleanly removed from the coating without leaving any residue after desorption. DETAILED DESCRIPTION

[0018] Hereinafter, the present invention is described in more detail with reference to Examples.

[0019] One aspect of the present invention can provide a coating protection film composition, which does not react with the vehicle body coating, is easy to peel off, and has good adhesion to protect the coating surface of automobiles or heavy equipment.

[0020] A specific example of the coating protective film composition of the present invention comprises an acrylic emulsion resin, a polyurethane dispersion and a polyolefin resin, wherein the weight average molecular weight of the acrylic emulsion resin is 200,000 to 300,000 g / mol, and the glass transition temperature is 50 to 80°C; the weight average molecular weight of the polyurethane dispersion is 40,000 to 60,000 g / mol, and the glass transition temperature is -70 to -20°C.

[0021] From the above content, it can be seen that the following effects are achieved: when the acrylic emulsion resin and the polyurethane dispersion have a weight average molecular weight and a glass transition temperature within a specific range, the drying speed and cross-linking density of the coating can be adjusted, the appearance characteristics of the coating as well as the physical and mechanical properties such as water resistance and solvent resistance can be improved, the surface tension of the composition can be adjusted without reacting with the vehicle body coating, and the coating has suitable adhesion to protect the coating.

[0022] The coating protective film composition of the present invention may further include one or more additives selected from the group consisting of the following components: a neutralizer, a solvent, a dispersant, a leveling agent, a defoaming agent, a UV stabilizer, a pigment, a thickener, and a preservative.

[0023] Hereinafter, the above components will be described in detail.

[0024] <Acrylic emulsion resin>

[0025] The acrylic emulsion resin plays a role in improving the storage stability and water resistance of the composition for a paint protection film and ensuring the strength and adhesion of the paint protection film produced therefrom.

[0026] The acrylic emulsion resin may be directly synthesized according to a known method or a commercially available product. For example, the acrylic emulsion resin may contain units derived from monomers, and the units derived from monomers are selected from one or more of the group consisting of the following components: allyl methacrylate (AMA), methyl methacrylate (MMA), ethyl acrylate (EA), ethyl methacrylate (EMA), hydroxyethyl acrylate (HEA) and methyl methacrylate (MAA). In another example, the acrylic emulsion resin as a monomer may be made from a mixture containing the following components: allyl methacrylate (AMA), methyl methacrylate (MMA), ethyl acrylate (EA), ethyl methacrylate (EMA), hydroxyethyl acrylate (HEA) and methyl methacrylate (MAA).

[0027] In addition, the mixture may further include a divalent acrylic acid monomer, for example, the divalent acrylic acid monomer includes: 1,4-Butanediol diacrylate, 1,4-Butanediol dimethacrylate, 1,5-Pentanedioldimethacrylate, 1,6-Hexanediol diacrylate, 1,6-Hexanediol dimethacrylate, 1,9-Nonanediol dimethacrylate, 1,10-Decanedioldimethacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, etc.

[0028] The viscosity of the acrylic emulsion resin at 25°C can be 30 to 100 cps or 50 to 80 cps. When the viscosity of the acrylic emulsion resin at 25°C is within the above range, the viscosity of the coating protective film composition is appropriate, and has an effect of improving operability. When the viscosity of the acrylic emulsion resin at 25°C is lower than the above range, the resulting coating film will not form due to the low viscosity of the composition, and there will be problems of reduced fluidity, adhesion and scratch resistance of the coating. When it exceeds the above range, the resulting coating film will have a problem of reduced appearance characteristics due to insufficient operability of the composition.

[0029] The pH of the acrylic emulsion resin may be 5 to 9 or 6 to 8. When the pH of the acrylic emulsion resin is within the above range, the viscosity of the coating protective film composition is appropriate, and the operability is improved and the storage stability is improved. When the pH of the acrylic emulsion resin is lower than the above range, the viscosity of the composition is too low, the coating film produced will not be formed, and there will be problems of reduced fluidity, adhesion and scratch resistance of the coating. When it exceeds the above range, the operability of the composition is insufficient, and the coating film produced will have a problem of reduced appearance characteristics.

[0030] The acid value (Av) of the acrylic emulsion resin may be 3 to 6 mgKOH / g or 3.5 to 5.5 mgKOH / g. When the acid value of the acrylic emulsion resin is within the above range, the reactivity of the composition containing it can be adjusted, thereby improving the appearance characteristics of the prepared coating film. When the acid value of the acrylic emulsion resin is lower than the range, the storage stability of the prepared coating composition may be reduced due to reduced resin stability, and when it exceeds the range, the increase in the cohesiveness of the resin may lead to an increase in the viscosity of the composition, thereby causing problems of decreased operability and water resistance of the coating film.

[0031] The weight average molecular weight (Mw) of the acrylic emulsion resin can be 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 the above range, the prepared coating film has excellent long-term physical properties such as durability, adhesion, hardness and weather resistance. When the weight average molecular weight of the acrylic emulsion resin is lower than the above range, due to the small molecular weight, the prepared coating film has insufficient performance in water resistance, weather resistance and scratch resistance. When it exceeds the above range, the increase in molecular weight will reduce fluidity, thereby making the operability of the coating protective film composition containing it worse, the surface flatness is not good, and there is a problem that it is difficult to prepare a coating film with excellent appearance.

[0032] The glass transition temperature (Tg) of the acrylic emulsion resin may be 50 to 80° C. or 60 to 70° C. When the glass transition temperature of the acrylic emulsion resin is within the above range, it will not react with the vehicle body coating, has suitable adhesion, and has the effect of improving the hardness and solvent resistance of the coating. When the glass transition temperature of the acrylic emulsion resin is lower than the above range, the drying speed and crosslinking density of the coating will decrease, and there is a problem that the hardness and solvent resistance of the prepared coating are insufficient. When it exceeds the above range, the coating will become brittle, and thus the appearance characteristics and peeling resistance of the prepared coating become insufficient.

[0033] In addition, the acrylic emulsion resin may be in the form of an emulsion dispersed in deionized water. For example, the acrylic emulsion is in the form of an emulsion dispersed in deionized water, and the average diameter may be 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 content of volatile organic compounds (VOC) in the coating, and when the average diameter is within the above range, the appearance and particle stability are good. .

[0034] Based on the total weight of the composition for the coating protective film, the content of the acrylic emulsion resin in the composition is 30 to 50% by weight or 35 to 45% by weight. When the content of the acrylic emulsion resin is included in the above content range, the coating film adhesion, durability, hardness and scratch resistance are improved. When the content of the acrylic emulsion resin is lower than the above range, due to the reduced drying property, there is a problem of reduced coating film adhesion, gloss, hardness and durability. When it exceeds the above range, due to the high drying speed, the coating operability and coating fluidity of the composition are insufficient, there is a problem of reduced coating film appearance and scratch resistance, and increased residual amount after the coating film is removed.

[0035] <Polyurethane dispersion>

[0036] The polyurethane dispersion used in the coating protective film composition of the present invention plays the role of improving the adhesion of the composition and enhancing the flexibility and tensile strength.

[0037] The polyurethane dispersion may be prepared by reacting a polyol, a diisocyanate and an acid. In this case, the polyol may be one or more selected from the group consisting of the following components: 1,6-hexanediol, ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, trimethylol propane, butanediol, 1,4-hexanediol and 3-methyl pentanediol.The diisocyanate may be one or more selected from the group consisting of isophorone diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, propylene diisocyanate, ethylene diisocyanate, 2,3-dimethylethylene diisocyanate, 1-methyltrimethylene diisocyanate, 1,3-cyclopentene diisocyanate, 1,4-cyclopentene diisocyanate, 1,4-cyclopentene diisocyanate, 1,3-cyclopentene diisocyanate, 1,4-cyclopentene diisocyanate, 1,4-cyclopentene diisocyanate, 1,3-cyclopentene diisocyanate, 1,4-cyclopentene diisocyanate, 1,4-cyclopentene diisocyanate, 1,3-cyclopentene diisocyanate, 1,4-cyclopentene diisocyanate, 1,3-cyclopentene diisocyanate, 1,4-cyclopentene diisocyanate, 1,3-cyclopentene diisocyanate, 1,4-cyclopentene diisocyanate, 1,3-cyclopentene diisocyanate, 1,4-cyclopentene diisocyanate, 1,3-cyclopentene diisocyanate, 1,4-cyclopentene diisocyanate, 1,3-cyclopentene diisocyanate, 1,3-cyclopentene diisocyanate, 1,4-cyclopentene diisocyanate, 1,4-cyclopentene diisocyanate, 1,3-cyclopentene diisocyanate. diisocyanate), 1,2-cyclopentyl diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluenediisocyanate, 2,6-toluene diisocyanate, oligomer diisocyanate, isophorone diisocyanate, 4,4-diphenyl propane diisocyanate, xylenediisocyanate and 1,1,6,6-tetramethylhexamethylene diisocyanate.Furthermore, the acid may be one or more selected from the group consisting of adipic acid, dimethylol propionic 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. In addition, the polyurethane dispersion is in the form of a polyurethane resin dispersed in a solvent, for example, the polyurethane dispersion may be a dispersion dispersed in deionized water.

[0038] In addition, the aqueous medium for dispersing the polyurethane resin may be an aqueous solvent or a mixed medium of water and a hydrophilic organic solvent. For example, the aqueous solvent may be tap water, ion exchange water, distilled water, deionized water, etc. In particular, ion exchange water may be used to prevent the particles from becoming unstable due to easy addition of water or the influence of salt. In addition, the hydrophilic organic solvent may be a low-order monovalent alcohol such as methanol, ethanol, and propanol; a polyvalent alcohol such as ethylene glycol and glycerol; and a non-protonic hydrophilic organic solvent such as N-methylmorpholine, dimethyl sulfoxide, and dimethylformamide.

[0039] The solid powder content (NV) of the polyurethane dispersion can be 30 to 50% by weight or 35 to 45% by weight of the total weight of the dispersion. When the solid powder content of the polyurethane dispersion is within the above range, the storage stability of the resin and the storage stability of the coating protective film composition are improved, and the operability is good. When the solid powder content of the polyurethane dispersion is lower than the above range, due to the low viscosity, there is a problem that the coating protective film composition containing it has insufficient operability. When it exceeds the above range, due to the high viscosity of the polyurethane dispersion, the stability in the reaction is reduced, the dispersion stability is deteriorated, and agglomeration occurs after a period of time.

[0040] The viscosity of the polyurethane dispersion at 25°C can be 10 to 300 cps or 20 to 250 cps. When the viscosity of the polyurethane dispersion at 25°C is within the above range, the viscosity of the coating protective film composition is appropriate, which has the effect of improving operability. When the viscosity of the polyurethane dispersion at 25°C is lower than the above range, the coating film produced will not be formed due to the low viscosity of the composition, and there will be problems of reduced fluidity, adhesion and scratch resistance of the coating. When it exceeds the above range, the composition is not easy to operate, and there will be problems of reduced appearance characteristics of the coating film.

[0041] The pH of the polyurethane dispersion may be 6 to 8 or 6.3 to 7.7. When the pH of the polyurethane dispersion is within the above range, the viscosity of the coating protective film composition is appropriate, which has the effect of improving operability. When the pH of the polyurethane dispersion is lower than the above range, the viscosity of the composition is too low, the coating film produced will not be formed, and there will be problems of reduced fluidity, adhesion and scratch resistance of the coating. When it exceeds the above range, the operability of the composition is insufficient, and there will be a problem of reduced appearance characteristics of the coating film produced.

[0042] The weight average molecular weight (Mw) of the polyurethane dispersion can be 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 the above range, the smoothness of the coating protective film composition is improved, and a soft coating is formed, which has the effect of improving the adhesion and wear resistance between the coating and the vehicle body. When the weight average molecular weight of the polyurethane dispersion is lower than the above range, due to the small molecular weight, there is a problem of decreased mechanical properties of the prepared coating, and when it exceeds the above range, due to the increase in molecular weight, the fluidity is reduced, and there is a problem that the coating becomes brittle, the smoothness becomes low, and the scratch resistance is reduced.

[0043] The glass transition temperature (Tg) of the polyurethane dispersion may be -70 to -20°C or -60 to -30°C. When the glass transition temperature of the polyurethane dispersion is within the above range, the flexibility and hardness of the coating film are improved. When the glass transition temperature of the polyurethane dispersion is lower than the above range, the drying speed of the coating protective film composition is delayed, and there is a problem that the prepared coating film has insufficient solvent resistance and peeling resistance. When it exceeds the above range, the coating film becomes brittle, and the coating film has insufficient appearance characteristics and hardness.

[0044] Based on the total weight of the composition for coating protective film, the content of polyurethane dispersion is 20 to 30% by weight or 22 to 28% by weight, which can be included in the composition. When the polyurethane dispersion is included in the above content range, it can have the effect of improving tensile strength, flexibility, elongation, adhesion, wear resistance, scratch resistance and coating flatness. When the content of polyurethane dispersion in the composition is lower than the above range, there is a problem of reduced flexibility leading to reduced tensile strength and scratch resistance. When it exceeds the above range, due to the high viscosity of the composition, the operability and drying properties are reduced, and there is a problem of reduced appearance and mechanical properties.

[0045] <Polyolefin resin>

[0046] The polyolefin resin increases the surface tension of the paint protection film composition, which enables suitable adhesion to the vehicle body paint film, and does not react with the vehicle body paint film to remove the paint film cleanly, providing excellent removability.

[0047] Polyolefin resins can include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ethylene-propylene copolymers, metallocene-polyethylene, polypropylene monomer polymers, polypropylene copolymers, metallocene-polypropylene, polypropylene monomer polymers, copolymers with enhanced physical properties-composite resins, etc.

[0048] For example, the polyolefin resin may be halogenated or modified to include a carboxyl group in the polymer, preferably polyethylene, polypropylene, polybutadiene, polyisoprene, polystyrene or copolymers of any two or more thereof. The polyolefin resin may also be modified into a resin, such as a maleic resin. In a specific example, the (modified) polyolefin may be selected from one or more of the following components: a halogenated polyolefin maleic acid copolymer such as a chlorinated polypropylene maleic resin, a polyolefin maleic acid copolymer, a styrene / ethylene-butylene, a styrene / butadiene, a styrene / ethylene-propylene or a styrene / isoprene copolymer. Suitable polyolefins include: products produced by Toyobo Co, Ltd and sold under the trademarks Hardlen NZ-1004, Hardlen NZ-1015, Hardlen EH-801J, Hardlen CY-9124 / 9122; and products produced by KRATON Performance Polymers Inc and sold under the trademarks Kraton G1643E and Kraton G1640ES.

[0049] The solid powder content (NV) of the polyolefin resin in the total weight of the dispersion may be 20 to 40% by weight or 25 to 35% by weight. When the solid powder content of the polyolefin resin is within the above range, the storage stability of the resin and the storage stability of the coating protective film composition can be improved, and the operability is good. When the solid powder content of the polyolefin resin is lower than the above range, the viscosity becomes too low, and there is a problem that the coating protective film composition containing it is not sufficiently operable. When it exceeds the range, the viscosity of the polyolefin resin is too high, resulting in reduced stability in the reaction, poor dispersion stability, and coagulation after a period of time.

[0050] 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 the above range, the viscosity of the coating protective film composition is appropriate and the operability is improved. When the viscosity of the polyolefin resin at 25°C is lower than the above range, the coating film prepared will not be formed due to the low viscosity of the composition, and there will be problems of reduced fluidity, adhesion and scratch resistance of the coating. When it exceeds the above range, the coating film prepared will have a problem of reduced appearance characteristics due to insufficient operability of the composition.

[0051] The pH of the polyolefin resin may be 6 to 8 or 6.3 to 7.7. When the pH of the polyolefin resin is within the above range, the viscosity of the coating protective film composition is appropriate and the operability is improved. When the pH of the polyolefin resin is lower than the above range, the viscosity of the composition is too low, the coating film produced will not be formed, and there will be problems of reduced fluidity, adhesion and scratch resistance of the coating. When it exceeds the above range, the operability of the composition is insufficient, and the coating film produced will have a problem of reduced appearance characteristics.

[0052] The weight average molecular weight (Mw) of the polyolefin resin can be 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 the above range, the flatness of the coating protective film composition is improved, forming a flexible (soft) coating film, having suitable adhesion to the vehicle body coating film, and having the effect of improving scratch resistance and hardness. When the weight average molecular weight of the polyolefin resin is lower than the above range, due to the small molecular weight, there is a problem of decreased mechanical properties of the prepared coating film. When it exceeds the above range, due to the increase in molecular weight, the fluidity is reduced, the coating film becomes brittle (Brittle), the flatness and scratch resistance are reduced, and the amount of residue after the coating film is removed becomes more.

[0053] The content of the polyolefin resin may be 25 to 40% by weight or 28 to 36% by weight based on the total weight of the composition for coating protection film. When the content of the polyolefin resin is within the above range, the adhesion is good, the discoloration of the pigment is prevented, the appearance is excellent, and the appropriate peelability is maintained. When the content of the polyolefin resin is lower than the above range, there are problems such as reduced adhesion and increased residual amount after removal of the coating film. When the content exceeds the above range, the compatibility with other components and the physical properties of the composition for coating protection film may be reduced.

[0054] The acrylic emulsion resin and the polyolefin resin may be mixed for use, and the weight ratio thereof may be 1:0.7 to 1, for example, 1:0.75 to 0.95.

[0055] When the mixing ratio of the acrylic emulsion resin to the polyolefin resin corresponds to the above range, suitable drying properties can be maintained, suitable adhesion to the vehicle body coating film can be achieved, and no residue is left after removal, and the coating film can be removed cleanly.

[0056] <Solvent>

[0057] Among the solvents, the basic solvent is water, and an organic solvent may be further included. The aqueous solvent may be ion exchange water, distilled water, deionized water, etc. In addition, the organic solvent may improve storage stability, provide quick-drying properties and adhesive functions, and is not particularly limited as long as there is no problem in the preparation of the coating protective film composition, and may be an alcohol-based solvent, such as butyl cellosolve, butyl carbitol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol.

[0058] The content of the solvent may be 0.5 to 5% by weight based on the total weight of the coating protection film composition. When the solvent is used within the above range, the viscosity can be easily adjusted. The coating protection film using the coating protection film composition can obtain excellent flatness and coating operability.

[0059] <Additives>

[0060] Adding additives to the coating protective film composition within a given content range can achieve the purpose of the invention including additional effects such as improved wettability and leveling when applied. For example, the additives can include neutralizers, dispersants, leveling agents, defoamers, UV stabilizers, pigments, thickeners, preservatives, etc.

[0061] The content of the additive may be 1 to 3 wt % or 1.5 to 2.5 wt % based on the total weight of the coating protection film composition. When used within the above range, the coating protection film composition can maintain excellent storage stability.

[0062] Another aspect of the present invention is to provide a coating protection film made of a coating protection film composition, which is easy to peel off and has good adhesion to protect the coating surface of automobiles or heavy equipment.

[0063] The coating protection film of the present invention is prepared by curing the coating protection film composition of the present invention.

[0064] Specifically, the coating protective film composition of the present invention is applied to the coated body by spraying, brushing or rolling, with a coating thickness of 10 to 100 μm, and then cured by room temperature drying, oven curing or IR lamp to form a coating protective film.

[0065] Hereinafter, the present invention will be further described in detail through examples.

[0066] However, these embodiments are only used to help understand the present invention, and these embodiments will not limit the scope of the present invention in any way.

[0067] Example

[0068] The components in Tables 1 to 3 below were used, starting with the resin, followed by stirring, and the solvent and additives were added in sequence. Through the above process, a composition for a coating protective film was prepared.

[0069] Comparative Example

[0070] The components in Tables 4 to 5 below were used, starting with the resin, followed by stirring, and the solvent and additives were added in sequence. Through the above process, a composition for a coating protective film was prepared.

[0071]

Table 1

[0072]

[0073]

[0074]

Table 2

[0075]

[0076]

[0077]

Table 3

[0078]

[0079]

[0080]

Table 4

[0081]

[0082]

[0083]

Table 5

[0084]

[0085]

[0086] The specific ingredients used in preparing the coating protective film composition in Tables 1 to 5 are shown in Table 6 below.

[0087]

Table 6

[0088]

[0089]

[0090] Test example

[0091] The coating protection film compositions of Examples and Comparative Examples were prepared by mixing the components in Tables 1 to 5, and then coating protection films were prepared using the compositions. Then, the physical properties were evaluated using the following methods, and the results are recorded in Tables 7 and 8 below.

[0092] Coating method

[0093] The compositions prepared in the examples and comparative examples were sprayed onto a body coated with a clear coating for automobiles to a thickness of 30 μm, and then cured at 80° C. for 3 minutes to form a film.

[0094] Physical property evaluation

[0095] 1) Dryness: The duration of dryness to touch without sticking the coating when the index finger briefly touched the coated test piece was tested. According to the test results, when the dryness to touch duration is more than 2 minutes and less than 7 minutes, it is considered to meet the mechanical property requirements for the coating protective film.

[0096] 2) Adhesion and residue: Apply the coating composition, dry at room temperature for 24 hours, and then place it at 70°C for one week. Then, place it at room temperature for one hour, and then use an Instron instrument to perform an adhesion test and detect the amount of residue. According to the test results, when the adhesion is greater than 0.4 kg / inch and less than 1.5 kg / inch, it is considered that the adhesion requirements for the coating protective film are met.

[0097] 3) Solvent resistance: Isopropyl alcohol, ethanol, methyl ethyl ketone and butanone were applied to the coating surface, with a coating thickness of 0.1 ml, and left for 5 minutes, and then the solvent resistance was confirmed. When no change was found on the coating surface after visual observation, it was rated as excellent (◎). When the coating surface expanded, cracked, torn or discolored, it was rated as good (○), fair (△), and poor (X).

[0098] 4) Water resistance: The prepared coating film was immersed in a 40°C constant temperature bath for 10 days, and then the adhesion test was performed and the appearance was evaluated. When there was no bubble and no peeling at all, it was rated as excellent (◎), when there was no bubble and the scale line indicated partial peeling, it was rated as good (○), when there was no bubble and one side peeled less than 1 / 4, it was rated as fair (△), and when there was bubble or one side peeled more than 1 / 4, it was rated as poor (X).

[0099]

Table 7

[0100]

[0101]

[0102]

Table 8

[0103]

[0104]

[0105] The coating protective films made by using the compositions in the examples all have excellent physical properties. The solvent resistance of comparative examples 1 to 4 and 6 to 10 is poor, and the water resistance of comparative examples 3 to 4, 6, 8, 10 and 11 is poor. The flow rate of comparative example 5 exceeds the standard.

[0106] Various embodiments of the present invention are described below.

[0107] (1) A composition for a coating protective film: comprising an acrylic emulsion resin, a polyurethane dispersion and a polyolefin resin, wherein the weight average molecular weight of the acrylic emulsion resin is 200,000 to 300,000 g / mol and the glass transition temperature is 50 to 80°C; the weight average molecular weight of the polyurethane dispersion is 40,000 to 60,000 g / mol and the glass transition temperature is -70 to -20°C.

[0108] (2) Composition for coating protective film: The acid value of acrylic emulsion resin is 3 to 6 mgKOH / g, and the viscosity is 30 to 100 cps at 25°C.

[0109] (3) Composition for coating protective film: The weight average molecular weight of the polyolefin resin is 70,000 to 90,000 g / mol, and the viscosity at 25°C is 10 to 250 cps.

[0110] (4) Composition for coating protective film: based on the total weight of the composition for coating protective film, the acrylic emulsion resin is 30 to 50% by weight, the polyurethane dispersion is 20 to 30% by weight, and the polyolefin resin is 25 to 40% by weight.

[0111] (5) Coating protection film: formed by curing the coating protection film composition according to any one of items (1) to (4).

Claims

1. A coating protective film composition, characterized in that: Contains acrylic emulsion resin, polyurethane dispersion and polyolefin resin, The weight average molecular weight of the acrylic emulsion resin is 200,000 to 300,000 g / mol, and the glass transition temperature is 50 to 80° C. The weight average molecular weight of the polyurethane dispersion is 40,000 to 60,000 g / mol, and the glass transition temperature is -70 to -20°C.

2. The coating protective film composition according to claim 1, characterized in that: The acrylic emulsion resin has an acid value of 3 to 6 mgKOH / g and a viscosity of 30 to 100 cps at 25°C.

3. The coating protective film composition according to claim 1, characterized in that: The polyolefin resin has a weight average molecular weight of 70,000 to 90,000 g / mol and a viscosity of 10 to 250 cps at 25°C.

4. The coating protective film composition according to claim 1, characterized in that: Based on the total weight of the coating protective film composition, the content of the acrylic emulsion resin is 30 to 50 weight %, the content of the polyurethane dispersion is 20 to 30 weight %, and the content of the polyolefin resin is 25 to 40 weight %.

5. A coating protection film produced by curing the composition for coating protection films according to any one of claims 1 to 4.

Images