Photocurable composition, coating layer containing the cured product, and process film

Abstract

The present invention provides a photocurable composition that is excellent in coatability and can realize a coating layer with excellent surface quality and thickness uniformity, a coating layer including a cured product of the photocurable composition, and a process film including the coating layer.

Description

[Technical Field]

[0001] This specification claims the benefit of the filing date of Korean Patent Application No. 10-2022-0076697, filed with the Korean Intellectual Property Office on June 23, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a photocurable composition, a coating layer containing the cured product, and a process film. [Background technology]

[0003] In various fields, such as the manufacturing process of electronic control devices and display panels, processing films are used to process objects, and the processing films are required to have sufficient stress relaxation performance to protect the objects from impacts that occur during the processing of the objects.

[0004] In addition, the object may be exposed to heat during processing, and therefore, there is a demand for a process film that has heat resistance and does not deform or break even when exposed to heat while maintaining stress relaxation performance.

[0005] Therefore, there is a current need for technology that can produce process films that have excellent stress relaxation properties and heat resistance. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides a photocurable composition that can realize a coating layer that has excellent coating properties and surface quality as well as excellent stress relaxation performance and heat resistance, a coating layer including a cured product of the photocurable composition, and a process film including the coating layer.

[0007] However, the problems to be solved by the present invention are not limited to those described above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0008] One embodiment of the present invention provides a photocurable composition comprising: a urethane (meth)acrylate resin syrup containing a urethane (meth)acrylate resin, which is a reaction product of a polyalkylene carbonate urethane prepolymer having an isocyanate terminal group and a reactive group-containing (meth)acrylate compound, and a (meth)acrylate monomer mixture; a polyfunctional urethane (meth)acrylate compound; and a polyfunctional (meth)acrylate compound; wherein the (meth)acrylate monomer mixture contains a first (meth)acrylate monomer containing an alkyl group, a second (meth)acrylate monomer containing an alicyclic alkyl group, a third (meth)acrylate monomer containing a polar functional group, a fourth (meth)acrylate monomer containing an aromatic group, and a fifth (meth)acrylate monomer containing a polar functional group and an aromatic group.

[0009] Another embodiment of the present invention provides a coating layer comprising a cured product of the photocurable composition.

[0010] Furthermore, one embodiment of the present invention provides a process film comprising the coating layer. [Effects of the Invention]

[0011] The photocurable composition according to one embodiment of the present invention has excellent coating properties and can realize a coating layer with excellent surface quality and thickness uniformity.

[0012] Furthermore, a coating layer having excellent stress relaxation properties and heat resistance can be produced by using the photocurable composition according to one embodiment of the present invention.

[0013] Furthermore, the coating layer according to an embodiment of the present invention has a low TTV (Total Thickness Variation), thereby providing excellent surface quality and thickness uniformity.

[0014] Furthermore, the coating layer according to one embodiment of the present invention can have excellent stress relaxation performance and heat resistance.

[0015] Furthermore, the processing film according to one embodiment of the present invention has excellent stress relaxation properties and heat resistance, and can be easily applied to processing processes in various fields such as electronic control devices, semiconductors, and display panels.

[0016] The effects of the present invention are not limited to those described above, and effects not mentioned will be clearly understood by those skilled in the art from the present specification and the accompanying drawings. DETAILED DESCRIPTION OF THE INVENTION

[0017] Throughout this specification, when a part is described as "comprising" a certain element, this means that it can further include other elements, but not excluding other elements, unless otherwise specified.

[0018] Throughout this specification, when a member is said to be "on" another member, this includes not only when the member is in contact with the other member, but also when there is another member between the two members.

[0019] Throughout this specification, the unit "parts by weight" can refer to the weight ratio between each component.

[0020] Throughout this specification, the term "(meth)acrylate" is used generically to refer to acrylate and methacrylate.

[0021] Throughout this specification, terms including ordinal numbers, such as "first" and "second," are used to distinguish one component from another, and are not limited by the ordinal number. For example, within the scope of the invention, a first component may be termed a second component, and similarly, a second component may be termed a first component.

[0022] Throughout this specification, the term "prepolymer" may refer to a polymer in which some degree of polymerization has occurred between compounds, or may refer to a polymer that is not fully polymerized and is capable of further polymerization.

[0023] Throughout this specification, the "weight average molecular weight" and "number average molecular weight" of a compound are calculated using the molecular weight and molecular weight distribution of that compound. Specifically, a sample of the compound at a concentration of 1 wt% is prepared by adding tetrahydrofuran (THF) and the compound to a 50 ml glass bottle. The standard (polystyrene) and the sample are filtered through a filter (pore size 0.45 μm) and then injected into a GPC injector. The elution time of the sample is compared with the calibration curve of the standard sample to obtain the molecular weight and molecular weight distribution of the compound. An Infinity II 1260 (Agilient) can be used as the measuring instrument, with a flow rate of 1.00 mL / min and a column temperature of 35.0 °C.

[0024] Throughout this specification, the viscosity of a compound (or composition) may be a value measured using a Brookfield viscometer at a given temperature. Specifically, after degassing the compound (or composition) to a bubble-free state, 0.5 mL of the compound (or composition) is sampled using a 5 mL syringe, and the viscosity is measured for 10 minutes using a Brookfield HB40 spindle while maintaining a constant temperature (25°C). The cP value at which no change in viscosity occurs is measured.

[0025] Throughout this specification, the term "alkyl group" can refer to a group containing a chain hydrocarbon structure with no unsaturated bonds within the functional group, and the term "alicyclic alkyl group" can refer to a group containing a carbon ring structure with no unsaturated bonds within the functional group, and can refer to a group containing a monocyclic ring or multiple rings.

[0026] The present specification will be explained in more detail below.

[0027] One embodiment of the present invention provides a photocurable composition comprising: a urethane (meth)acrylate resin syrup containing a urethane (meth)acrylate resin, which is a reaction product of a polyalkylene carbonate urethane prepolymer having an isocyanate terminal group and a reactive group-containing (meth)acrylate compound, and a (meth)acrylate monomer mixture; a polyfunctional urethane (meth)acrylate compound; and a polyfunctional (meth)acrylate compound; wherein the (meth)acrylate monomer mixture contains a first (meth)acrylate monomer containing an alkyl group, a second (meth)acrylate monomer containing an alicyclic alkyl group, a third (meth)acrylate monomer containing a polar functional group, a fourth (meth)acrylate monomer containing an aromatic group, and a fifth (meth)acrylate monomer containing a polar functional group and an aromatic group.

[0028] The photocurable composition according to one embodiment of the present invention has excellent coating properties and can realize a coating layer with excellent surface quality and thickness uniformity. Furthermore, the photocurable composition can be used to produce a coating layer with excellent stress relaxation properties and heat resistance.

[0029] According to one embodiment of the present invention, the urethane (meth)acrylate resin syrup may contain the urethane (meth)acrylate resin and a (meth)acrylate monomer mixture.

[0030] According to one embodiment of the present invention, the weight-average molecular weight of the urethane (meth)acrylate resin may be 20,000 g / mol or more and 50,000 g / mol or less. Specifically, the weight-average molecular weight of the urethane (meth)acrylate resin may be 20,000 g / mol or more and 47,000 g / mol or less, 20,000 g / mol or more and 45,000 g / mol or less, 20,000 g / mol or more and 42,000 g / mol or less, 20,000 g / mol or more and 40,000 g / mol or less, 20,000 g / mol or more and 38,000 g / mol or less, 20,000 g / mol or more and 35,000 g / mol or less, or 20,000 g / mol or more and 33,000 g / mol or less. ,000 g / mol or less, 20,000 g / mol to 31,000 g / mol, 25,000 g / mol to 50,000 g / mol, 26,000 g / mol to 48,000 g / mol, 27,000 g / mol to 45,000 g / mol, 28,000 g / mol to 40,000 g / mol, 29,000 g / mol to 38,000 g / mol, or 30,000 g / mol to 35,000 g / mol.

[0031] When the weight-average molecular weight of the urethane (meth)acrylate resin is within the above-mentioned range, the photocurable composition can realize a coating layer with improved stress relaxation performance, heat resistance, and mechanical properties. Furthermore, by adjusting the weight-average molecular weight of the urethane (meth)acrylate resin within the above-mentioned range, deterioration of the coating properties of the photocurable composition can be suppressed.

[0032] According to one embodiment of the present invention, the viscosity of the urethane (meth)acrylate resin syrup may be 500 cP to 3,000 cP. Specifically, the viscosity of the urethane (meth)acrylate resin syrup at 25°C may be 500 cP to 3,000 cP, 550 cP to 2,800 cP, 600 cP to 2,700 cP, 800 cP to 2,500 cP, 1,000 cP to 2,200 cP, 1,400 cP to 2,000 cP, 500 cP to 1,500 cP, or 2,000 cP to 3,000 cP. The viscosity of the urethane (meth)acrylate resin syrup at 25°C may be measured using a Brookfield HB40 spindle, as described above.

[0033] When the viscosity of the urethane (meth)acrylate resin syrup at 25°C is within the above-mentioned range, the coatability of the photocurable composition can be effectively improved. Furthermore, by adjusting the viscosity of the urethane (meth)acrylate resin syrup within the above-mentioned range, the surface quality and thickness uniformity of the coating layer produced from the photocurable composition can be improved. Specifically, the total thickness variation (TTV) of the coating layer, which will be described later, can be more effectively reduced.

[0034] According to one embodiment of the present invention, the urethane (meth)acrylate resin may contain a carbonate repeating unit containing an alkylene having 1 to 10 carbon atoms and at least one side chain having 1 to 3 carbon atoms. Because the urethane (meth)acrylate resin contains a carbonate repeating unit containing an alkylene having 1 to 10 carbon atoms and a side chain having 1 to 3 carbon atoms, the urethane (meth)acrylate resin may have a large weight-average molecular weight, and the urethane (meth)acrylate resin syrup may have a relatively low viscosity. Therefore, the photocurable composition containing the urethane (meth)acrylate resin syrup has improved wetting properties, excellent coatability, and improved surface quality and thickness uniformity of the produced coating layer. Furthermore, the photocurable composition may easily produce a coating layer with excellent stress relaxation properties and heat resistance.

[0035] According to one embodiment of the present invention, the polyalkylene carbonate-based urethane prepolymer may be a reaction product of a first mixture containing a polyalkylene carbonate-based polyol and a diisocyanate-based compound. Specifically, the polyalkylene carbonate-based urethane prepolymer is formed by a polymerization reaction between the polyalkylene carbonate-based polyol and the diisocyanate-based compound. That is, a reaction occurs between the isocyanate group of the diisocyanate-based compound and the hydroxy group of the polyalkylene carbonate-based polyol to form a urethane bond, thereby forming a polyalkylene carbonate-based urethane prepolymer having an isocyanate group at its terminal.

[0036] According to one embodiment of the present invention, the polyalkylene carbonate polyol may contain a carbonate repeating unit containing an alkylene having 1 to 10 carbon atoms and having at least one side chain having 1 to 3 carbon atoms bonded thereto. That is, the carbonate repeating unit containing an alkylene having 1 to 10 carbon atoms and having at least one side chain having 1 to 3 carbon atoms bonded thereto, which is contained in the urethane (meth)acrylate resin, may be derived from the polyalkylene carbonate polyol.

[0037] According to one embodiment of the present invention, the polyalkylene carbonate polyol can contain one or more carbonate repeating units. Specifically, at least one of the carbonate repeating units contained in the polyalkylene carbonate polyol may be a carbonate repeating unit containing an alkylene having 1 to 10 carbon atoms and at least one side chain having 1 to 3 carbon atoms bonded thereto. By using the polyalkylene carbonate polyol containing the carbonate repeating unit, it is possible to produce the urethane (meth)acrylate resin syrup having a high weight-average molecular weight and low viscosity.

[0038] For example, the carbonate repeating unit containing alkylene having 1 to 10 carbon atoms bonded to at least one side chain having 1 to 3 carbon atoms may be represented by the following chemical formula 2. [Chemical formula 2] [ka] In the above formula 2, R 11 is an alkylene having 1 to 10 carbon atoms, and R 12 is an alkyl group having 1 to 3 carbon atoms.

[0039] The alkylene having 1 to 10 carbon atoms contained in the carbonate repeating unit may be linear. The number of carbon atoms contained in the alkylene may be 3 to 8, 5 to 6, or 4 to 5. At least one alkyl group having 1 to 3 carbon atoms may be bonded to the main chain of the alkylene. Specifically, a methyl group, an ethyl group, or a propyl group may be bonded to the alkylene. More specifically, the carbonate repeating unit may include an alkylene having 4 to 6 carbon atoms bonded to a methyl group. When the number of carbon atoms of the alkylene contained in the carbonate repeating unit and the number of carbon atoms of the side chain are within the above-described ranges, the urethane (meth)acrylate resin syrup can have a high weight-average molecular weight and a low viscosity.

[0040] The polyalkylene carbonate polyol may contain two or more hydroxy groups. Specifically, the polyalkylene carbonate polyol may be a polyalkylene carbonate diol containing the carbonate repeating unit described above.

[0041] According to one embodiment of the present invention, the diisocyanate compound may include at least one of bis(isocyanatomethyl)cyclohexane, methylene diphenyl diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, metaxylene diisocyanate, dicyclohexylmethane diisocyanate, and tetramethylxylene diisocyanate, although the types of the diisocyanate compound are not limited to those described above.

[0042] According to one embodiment of the present invention, the diisocyanate compound may contain two or more diisocyanate compounds. Specifically, the diisocyanate compound may contain a chain alkylene diisocyanate compound and an alicyclic alkylene diisocyanate compound. For example, the chain alkylene diisocyanate compound may be isophorone diisocyanate, and the alicyclic alkylene diisocyanate compound may be hexamethylene diisocyanate. Using the diisocyanate compound containing a chain alkylene diisocyanate compound and an alicyclic alkylene diisocyanate compound, the urethane (meth)acrylate resin syrup having a high weight-average molecular weight and low viscosity can be effectively formed.

[0043] According to one embodiment of the present invention, the content of the diisocyanate compound in the first mixture may be 10 to 20 parts by weight based on 100 parts by weight of the polyalkylene carbonate polyol. Specifically, the content of the diisocyanate compound based on 100 parts by weight of the polyalkylene carbonate polyol may be 11.5 to 18 parts by weight, 12.5 to 16 parts by weight, 10 to 15 parts by weight, or 14 to 18 parts by weight. When the content of the diisocyanate compound is within the above-mentioned range, the polyalkylene carbonate urethane prepolymer is stably formed. Furthermore, by adjusting the content of the diisocyanate compound within the above-mentioned range, the urethane (meth)acrylate resin syrup having a high weight-average molecular weight and low viscosity can be effectively formed.

[0044] According to one embodiment of the present invention, the molar ratio of the polyalkylene carbonate polyol to the diisocyanate compound may be 1:1.15 to 1:1.5. Specifically, the molar ratio of the polyalkylene carbonate polyol to the diisocyanate compound may be 1:1.15 to 1:1.4, 1:1.15 to 1:1.3, 1:1.15 to 1:1.2, 1:1.2 to 1:1.5, 1:1.3 to 1:1.5, or 1:1.4 to 1:1.5. By adjusting the molar ratio of the polyalkylene carbonate polyol to the diisocyanate compound within the above-mentioned range, the viscosity and molecular weight of the urethane (meth)acrylate resin can be appropriately controlled, thereby effectively improving the vibration damping properties and heat resistance of the vibration damping layer.

[0045] According to one embodiment of the present invention, the first mixture may include a viscosity-adjusting monomer. By adding the viscosity-adjusting monomer to the first mixture, the polyalkylene carbonate-based urethane prepolymer may have an appropriate viscosity. By adjusting the viscosity of the polyalkylene carbonate-based urethane prepolymer using the viscosity-adjusting monomer, the polyalkylene carbonate-based urethane prepolymer may be easily polymerized with the reactive group-containing (meth)acrylate compound.

[0046] The viscosity-adjusting monomer may include at least one of isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, and trimethylcyclohexyl (meth)acrylate. Meanwhile, the viscosity-adjusting monomer contained in the first mixture may remain in the urethane (meth)acrylate resin syrup and be included in the (meth)acrylate monomer mixture described below. Specifically, the viscosity-adjusting monomer contained in the first mixture may constitute a part of the alicyclic alkyl group-containing second (meth)acrylate monomer contained in the urethane (meth)acrylate resin syrup. That is, the viscosity-adjusting monomer contained in the first mixture remains in the urethane (meth)acrylate resin syrup, thereby easily adjusting the viscosity of the urethane (meth)acrylate resin syrup to within the aforementioned range.

[0047] According to one embodiment of the present invention, the urethane (meth)acrylate resin may be a reaction product of a second mixture containing a polyalkylene carbonate-based urethane prepolymer having an isocyanate terminal group and a reactive group-containing (meth)acrylate compound. That is, the urethane (meth)acrylate resin is formed by a polymerization reaction between the polyalkylene carbonate-based urethane prepolymer and the reactive group-containing (meth)acrylate compound. Specifically, the urethane (meth)acrylate resin is formed by a reaction between the isocyanate group at the end of the polyalkylene carbonate-based urethane prepolymer and the reactive group of the reactive group-containing (meth)acrylate compound. As a result, the end of the urethane (meth)acrylate resin is capped by acrylate with the reactive group-containing (meth)acrylate compound. The second mixture may also contain a viscosity-controlling monomer, and the viscosity-controlling monomer contained in the second mixture may be a residue of the viscosity-controlling monomer contained in the first mixture.

[0048] According to one embodiment of the present invention, the reactive group of the reactive group-containing (meth)acrylate compound may include a hydroxy group (—OH). In terms of polymerization reactivity with the isocyanate group located at the terminal of the polyalkylene carbonate-based urethane prepolymer, a (meth)acrylate compound containing a hydroxy group as a reactive group may be used. The (meth)acrylate compound containing a hydroxy group as a reactive group may react with the isocyanate group located at the terminal of the polyalkylene carbonate-based urethane prepolymer to form a urethane bond. The urethane (meth)acrylate resin has a fast UV curing rate, and a cured product of a photocurable composition containing the urethane (meth)acrylate resin syrup may have excellent stress relaxation properties.

[0049] According to one embodiment of the present invention, the reactive group-containing (meth)acrylate compound may not contain a carboxyl group. That is, the reactive group-containing (meth)acrylate compound may not contain a carboxyl group as a reactive group. If the reactive group-containing (meth)acrylate compound contains a carboxyl group as a reactive group, it may not be highly reactive with the isocyanate group located at the end of the polyalkylene carbonate-based urethane prepolymer, making it difficult to form the urethane (meth)acrylate resin. Furthermore, if the reactive group-containing (meth)acrylate compound contains a carboxyl group, the stress relaxation performance of the cured product of the photocurable composition may be reduced.

[0050] Therefore, according to one embodiment of the present invention, the urethane (meth)acrylate resin can be easily formed using a (meth)acrylate compound that does not contain a carboxyl group as a reactive group, and a photocurable composition capable of forming a coating layer with excellent stress relaxation performance can be provided.

[0051] According to one embodiment of the present invention, the reactive group-containing (meth)acrylate compound can contain an alkylene having four or fewer carbon atoms. Specifically, the reactive group-containing (meth)acrylate compound can contain at least one of hydroxymethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate. The photocurable composition containing the reactive group-containing (meth)acrylate compound having an alkylene having four or fewer carbon atoms and the urethane (meth)acrylate resin derived from the polyalkylene carbonate urethane prepolymer can achieve a coating layer with excellent coatability, surface quality, and thickness uniformity, as well as excellent stress relaxation performance and heat resistance.

[0052] According to one embodiment of the present invention, the content of the reactive group-containing (meth)acrylate compound in the second mixture may be 1 to 10 parts by weight per 100 parts by weight of the polyalkylene carbonate-based urethane prepolymer. Specifically, the content of the reactive group-containing (meth)acrylate compound per 100 parts by weight of the polyalkylene carbonate-based urethane prepolymer may be 1.5 to 8.5 parts by weight, 2 to 7 parts by weight, 3.5 to 6.5 parts by weight, 1 to 6 parts by weight, 1.5 to 5.5 parts by weight, 2 to 5 parts by weight, 2 to 4.5 parts by weight, 3 to 10 parts by weight, 3.2 to 8.5 parts by weight, 3.5 to 7.5 parts by weight, 3.7 to 7 parts by weight, or 4 to 6.5 parts by weight.

[0053] By adjusting the content of the reactive group-containing (meth)acrylate compound within the above-mentioned range, the stress relaxation performance and mechanical properties of the coating layer including the cured product of the photocurable composition can be further improved. Furthermore, when the content of the reactive group-containing (meth)acrylate compound is within the above-mentioned range, deterioration of the coatability of the photocurable composition can be suppressed.

[0054] According to one embodiment of the present invention, the content of the urethane (meth)acrylate resin per 100 parts by weight of the urethane (meth)acrylate resin syrup may be 15 to 35 parts by weight, 17.5 to 32.5 parts by weight, 20 to 30 parts by weight, 23 to 28 parts by weight, 15 to 30 parts by weight, 18 to 28.5 parts by weight, 20 to 25 parts by weight, 20 to 35 parts by weight, 21.5 to 33 parts by weight, 22.5 to 30 parts by weight, or 25 to 27.5 parts by weight. When the content of the urethane (meth)acrylate resin is within the above-mentioned range, the photocurable composition can provide a coating layer with excellent surface quality and thickness uniformity. Furthermore, adjusting the content of the urethane (meth)acrylate resin within the above-mentioned range can further improve the stress relaxation performance and heat resistance of the coating layer.

[0055] According to one embodiment of the present invention, the urethane (meth)acrylate-based resin syrup may include a (meth)acrylate-based monomer mixture, which adjusts the viscosity of the urethane (meth)acrylate-based resin syrup and can also participate in the photocuring reaction of the photocurable composition described below.

[0056] According to one embodiment of the present invention, the content of the (meth)acrylate monomer mixture may be 65 to 85 parts by weight based on 100 parts by weight of the urethane (meth)acrylate resin syrup. Specifically, the content of the (meth)acrylate monomer mixture based on 100 parts by weight of the urethane (meth)acrylate resin syrup may be 67.5 to 82.5 parts by weight, 70 to 80 parts by weight, 72.5 to 77.5 parts by weight, 65 to 80 parts by weight, 68 to 77 parts by weight, or 70 to 75 parts by weight.

[0057] By adjusting the content of the (meth)acrylate monomer mixture within the above-mentioned range, the viscosity of the urethane (meth)acrylate resin syrup can be easily adjusted within the above-mentioned range. Furthermore, when the content of the (meth)acrylate monomer mixture satisfies the above-mentioned range, the coatability of the photocurable composition can be improved, and the surface quality and thickness uniformity of the coating layer produced using the photocurable composition can be effectively improved.

[0058] According to one embodiment of the present invention, the (meth)acrylate monomer mixture may include a first (meth)acrylate monomer containing an alkyl group; a second (meth)acrylate monomer containing an alicyclic alkyl group; a third (meth)acrylate monomer containing a polar functional group; a fourth (meth)acrylate monomer containing an aromatic group; and a fifth (meth)acrylate monomer containing a polar functional group and an aromatic group.

[0059] According to one embodiment of the present invention, the first (meth)acrylate monomer can contain a linear or branched chain alkyl group having 1 to 10 carbon atoms. For example, the alkyl group-containing first (meth)acrylate monomer can contain at least one of methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, sec-butyl (meth)acrylate, pentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, n-octyl-5-(meth)acrylate, and isooctyl (meth)acrylate.

[0060] According to one embodiment of the present invention, the content of the first (meth)acrylate monomer may be 2.5 to 7.5 parts by weight, 3.5 to 6.5 parts by weight, 4.5 to 5.5 parts by weight, 2.5 to 5 parts by weight, or 4.5 to 7.5 parts by weight, based on 100 parts by weight of the urethane (meth)acrylate resin syrup. By adjusting the content of the alkyl group-containing first (meth)acrylate monomer within the above-mentioned range, the viscosity of the photocurable composition can be appropriately adjusted, improving wettability and forming a more uniform and smooth coating surface. Furthermore, when the content of the alkyl group-containing (meth)acrylate monomer within the above-mentioned range, the mechanical properties and stress relaxation properties of a coating layer including a cured product of the photocurable composition can be improved.

[0061] According to one embodiment of the present invention, the second (meth)acrylate monomer can contain an alicyclic alkyl group having 5 to 10 carbon atoms. For example, the alicyclic alkyl group-containing second (meth)acrylate monomer can contain at least one of isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, and trimethylcyclohexyl (meth)acrylate.

[0062] According to one embodiment of the present invention, the content of the second (meth)acrylate monomer may be 5 to 35 parts by weight, 10 to 30 parts by weight, 15 to 25 parts by weight, 5 to 20 parts by weight, or 15 to 35 parts by weight, relative to 100 parts by weight of the urethane (meth)acrylate resin syrup. By adjusting the content of the alicyclic alkyl group-containing (meth)acrylate monomer within the above-mentioned range, the viscosity of the photocurable composition can be adjusted, thereby effectively improving the coatability and the mechanical properties of the coating layer.

[0063] Meanwhile, the alicyclic alkyl group-containing second (meth)acrylate monomer contained in the (meth)acrylate monomer mixture may be the viscosity-adjusting monomer contained in the first mixture, as described above. That is, the alicyclic alkyl group-containing second (meth)acrylate monomer contained in the (meth)acrylate monomer mixture may be the viscosity-adjusting monomer contained in the first mixture that remains in the photocurable composition. Therefore, when the content of the alicyclic alkyl group-containing second (meth)acrylate monomer is within the above-described range, the polyalkylene carbonate urethane prepolymer can be easily produced, and the polymerization of the polyalkylene carbonate urethane prepolymer and the reactive group-containing (meth)acrylate compound can be easily carried out.

[0064] According to one embodiment of the present invention, the polar functional group-containing third (meth)acrylate monomer may contain a hydroxy group as the polar functional group. Specifically, the polar functional group-containing third (meth)acrylate monomer may include at least one of 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 2-hydroxyethylene glycol (meth)acrylate, and 2-hydroxypropylene glycol (meth)acrylate.

[0065] According to one embodiment of the present invention, the content of the third (meth)acrylate monomer may be 5 to 15 parts by weight, 7.5 to 12.5 parts by weight, 5 to 10 parts by weight, or 8 to 15 parts by weight, relative to 100 parts by weight of the urethane (meth)acrylate resin syrup. By adjusting the content of the polar functional group-containing third (meth)acrylate monomer within the above-mentioned range, the wetting property and coatability of the photocurable composition can be improved, and the stress relaxation performance and heat resistance of the cured product of the photocurable composition can be improved.

[0066] According to one embodiment of the present invention, the aromatic group-containing quaternary (meth)acrylate monomer may contain an aromatic group having a carbon number of 6 to 20. For example, the aromatic group-containing quaternary (meth)acrylate monomer may contain at least one of phenylbenzyl (meth)acrylate, phenylthioethyl (meth)acrylate, O-phenylphenoxyethyl (meth)acrylate, and naphthylthioethyl (meth)acrylate.

[0067] According to one embodiment of the present invention, the content of the fourth (meth)acrylate monomer may be 15 to 25 parts by weight, 17.5 to 22.5 parts by weight, 15 to 22 parts by weight, or 18 to 25 parts by weight, relative to 100 parts by weight of the urethane (meth)acrylate resin syrup. When the content of the aromatic group-containing fourth (meth)acrylate monomer is within the above-mentioned range, the wetting properties of the photocurable composition can be improved, and the stress relaxation performance and heat resistance of a cured product of the photocurable composition can be improved.

[0068] According to one embodiment of the present invention, the fifth (meth)acrylate monomer containing a polar functional group and an aromatic group may contain, as the polar functional group, a hydroxy group and an aromatic group having 6 to 20 carbon atoms. For example, the fifth (meth)acrylate monomer containing a polar functional group and an aromatic group may include at least one of 2-hydroxy-3-phenoxyethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-hydroxy-3-phenoxybutyl (meth)acrylate, 2-acryloyloxyethyl 2-hydroxyethyl phthalate (Kyoeisha, HOA-MPE(N)), and 2-methacryloyloxyethyl 2-hydroxypropyl phthalate (Kyoeisha, HO-MPP(N)).

[0069] According to one embodiment of the present invention, the content of the fifth (meth)acrylate monomer may be 5 to 35 parts by weight, 10 to 30 parts by weight, 15 to 25 parts by weight, 5 to 25 parts by weight, or 15 to 35 parts by weight, relative to 100 parts by weight of the urethane (meth)acrylate resin syrup. When the content of the polar functional group- and aromatic group-containing fifth (meth)acrylate monomer is within the above-mentioned range, the stress relaxation performance and heat resistance of the cured product of the photocurable composition can be improved.

[0070] According to one embodiment of the present invention, the total content of the fourth (meth)acrylate monomer and the fifth (meth)acrylate monomer may be 30 parts by weight or more and 50 parts by weight or less, based on 100 parts by weight of the urethane (meth)acrylate resin syrup. When the total content of the fourth (meth)acrylate monomer and the fifth (meth)acrylate monomer contained in the photocurable composition is within the above-mentioned range, the photocurable composition can form a coating layer with excellent surface quality and thickness uniformity. In addition, the stress relaxation performance and heat resistance of the cured product of the photocurable composition can be improved.

[0071] According to one embodiment of the present invention, the weight ratio of the fourth (meth)acrylate monomer to the fifth (meth)acrylate monomer may be 1:0.5 to 1:1.5. By adjusting the weight ratio of the fourth (meth)acrylate monomer to the fifth (meth)acrylate monomer within the above range, the photocurable composition can realize a coating layer with excellent surface quality and thickness uniformity. In addition, the stress relaxation performance and heat resistance of the cured product of the photocurable composition can be improved.

[0072] According to one embodiment of the present invention, the photocurable composition may include a polyfunctional urethane (meth)acrylate compound. By including the polyfunctional urethane (meth)acrylate compound, the crosslinking reaction of the photocurable composition can be appropriately controlled, and the photocurable composition can realize a coating layer with improved mechanical properties and stress relaxation properties.

[0073] According to one embodiment of the present invention, the polyfunctional urethane (meth)acrylate compound may contain two or more (meth)acrylate groups as functional groups. Specifically, the polyfunctional urethane (meth)acrylate compound may contain 2 to 6 or 3 to 5 (meth)acrylate groups. The photocurable composition containing a polyfunctional urethane (meth)acrylate compound whose number of functional groups falls within the above-mentioned range can achieve a coating layer with improved stress relaxation performance and mechanical properties. The polyfunctional urethane (meth)acrylate compounds may be used alone or in combination with different types.

[0074] According to one embodiment of the present invention, the polyfunctional urethane (meth)acrylate compound may include a polymerized unit derived from caprolactone acrylate and three or more (meth)acrylate groups. Specifically, the polyfunctional urethane (meth)acrylate compound may include a compound represented by the following Chemical Formula 1: [Chemical formula 1] [ka] In Chemical Formula 1, R1, R2, and R3 are each independently an alkylene group having 2 to 10 carbon atoms, R4, R5, and R6 are each independently an alkylene group having 2 to 6 carbon atoms, R7, R8, and R9 are each independently a hydrogen atom or a methyl group, and n, j, and k are each independently an integer of 1 to 3. Specifically, in Chemical Formula 1, R1, R2, and R3 may each independently be an alkylene group having 3 to 8 carbon atoms, an alkylene group having 4 to 7 carbon atoms, or an alkylene group having 5 to 6 carbon atoms. Furthermore, R4, R5, and R6 may each independently be an alkylene group having 3 to 6 carbon atoms, or an alkylene group having 3 to 6 carbon atoms.

[0075] By including the polyfunctional urethane (meth)acrylate compound including the compound represented by Chemical Formula 1, it is possible to provide a photocurable composition that can appropriately control the crosslinking reaction of the photocurable composition and realize a coating layer with improved mechanical properties and stress relaxation characteristics.

[0076] According to one embodiment of the present invention, the polyfunctional urethane (meth)acrylate compound may include a compound represented by the following Chemical Formula 1-1. [Chemical formula 1-1] [ka]

[0077] According to one embodiment of the present invention, the weight-average molecular weight of the polyfunctional urethane (meth)acrylate compound may be 2,000 g / mol to 5,000 g / mol. Specifically, the weight-average molecular weight of the polyfunctional urethane (meth)acrylate compound may be 2,500 g / mol to 4,500 g / mol, 3,000 g / mol to 4,000 g / mol, 3,500 g / mol to 3,800 g / mol, 2,000 g / mol to 4,000 g / mol, 2,300 g / mol to 3,800 g / mol, 2,700 g / mol, or 3,800 g / mol. It may be greater than or equal to 3,600 g / mol, greater than or equal to 3,100 g / mol, greater than or equal to 3,500 g / mol, greater than or equal to 3,000 g / mol, greater than or equal to 5,000 g / mol, greater than or equal to 3,200 g / mol, greater than or equal to 4,800 g / mol, greater than or equal to 3,300 g / mol, greater than or equal to 4,500 g / mol, greater than or equal to 3,500 g / mol, greater than or equal to 4,200 g / mol, or greater than or equal to 3,700 g / mol, greater than or equal to 4,000 g / mol.

[0078] When the weight-average molecular weight of the polyfunctional urethane (meth)acrylate compound is within the above-mentioned range, the crosslinking reaction of the photocurable composition can be easily controlled, and the photocurable composition can easily produce a coating layer with excellent stress relaxation properties and mechanical properties. This prevents the coating layer from being deformed by external impact or other conditions, and suppresses a decrease in the stress relaxation properties of the coating layer. Furthermore, by adjusting the weight-average molecular weight of the polyfunctional urethane (meth)acrylate compound within the above-mentioned range, a decrease in the coatability of the photocurable composition can be suppressed.

[0079] According to one embodiment of the present invention, the content of the multifunctional urethane (meth)acrylate compound may be 0.5 to 2 parts by weight, 0.7 to 1.7 parts by weight, 1 to 1.5 parts by weight, 1.1 to 1.3 parts by weight, 0.5 to 1.5 parts by weight, or 1 to 2 parts by weight, based on 100 parts by weight of the urethane (meth)acrylate resin. By adjusting the content of the multifunctional urethane (meth)acrylate compound within the above-mentioned range, the coatability of the photocurable composition can be improved, thereby improving the surface quality and thickness uniformity of the coating layer described below. Furthermore, when the content of the multifunctional urethane (meth)acrylate compound within the above-mentioned range, the degree of crosslinking of the cured product of the photocurable composition can be effectively adjusted, thereby effectively improving the stress relaxation performance and mechanical properties of the coating layer.

[0080] According to one embodiment of the present invention, the photocurable composition may contain a polyfunctional (meth)acrylate compound. The polyfunctional (meth)acrylate compound may contain two or more (meth)acrylate groups as functional groups. Specifically, the polyfunctional (meth)acrylate compound may contain 2 to 6 or 2 to 5 (meth)acrylate groups. By using a polyfunctional (meth)acrylate compound whose number of functional groups falls within the above-mentioned range, the curing density of the photocurable composition can be adjusted and improved, and a coating layer with easily adjustable stress relaxation performance and tensile strength can be achieved.

[0081] According to one embodiment of the present invention, the polyfunctional (meth)acrylate compound may include at least one of hexanediol di(meth)acrylate, tripropylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethoxy tri(meth)acrylate, glycerin propoxylated tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. The polyfunctional (meth)acrylate compounds may be used alone or in combination.

[0082] According to one embodiment of the present invention, the content of the polyfunctional (meth)acrylate compound may be 0.5 to 1.5 parts by weight, 0.7 to 1.2 parts by weight, 0.5 to 1 part by weight, or 0.8 to 1.5 parts by weight, relative to 100 parts by weight of the urethane (meth)acrylate resin. By adjusting the content of the polyfunctional (meth)acrylate compound within the above-mentioned range, the stress relaxation performance and mechanical properties of the cured product of the photocurable composition can be improved. Furthermore, when the content of the polyfunctional (meth)acrylate compound is within the above-mentioned range, deterioration in the coatability of the photocurable composition and the surface quality of the coating film can be suppressed.

[0083] According to one embodiment of the present invention, the photocurable composition may include a photoinitiator. The photoinitiator may be any photoinitiator commonly used in the art. For example, the photoinitiator may be at least one of HP-8 (Miwon Specialty), Irgacure #651 (BASF), Irgacure #1173 (BASF), and CP-4 (Irgacure #184), but the type of the photoinitiator is not limited thereto.

[0084] According to one embodiment of the present invention, the content of the photoinitiator may be 0.5 to 3 parts by weight based on 100 parts by weight of the urethane (meth)acrylate resin. Specifically, the content of the photoinitiator may be 0.7 to 2.75 parts by weight, 1 to 2.5 parts by weight, 1.5 to 2.2 parts by weight, or 1.7 to 2 parts by weight based on 100 parts by weight of the urethane (meth)acrylate resin. By adjusting the content of the photoinitiator within the above range, the photocuring reaction of the photocurable composition can be effectively carried out.

[0085] According to one embodiment of the present invention, the viscosity of the photocurable composition may be 3,000 cP or less. Specifically, the viscosity of the photocurable composition at 25°C may be 400 cP or more and 3,000 cP or less. More specifically, the viscosity of the photocurable composition at 25°C may be 500 cP or more and 2,900 cP or less, 600 cP or more and 2,800 cP or less, 700 cP or more and 2,000 cP or less, 450 cP or more and 1,800 cP or less, 500 cP or more and 1,650 cP or less, 550 cP or more and 1,550 cP or less, 600 cP or more and 1,450 cP or less, 650 cP or more and 1,400 cP or less, 700 cP or more and 1,350 cP or less, 1,000 cP or more and 3,000 cP or less, 1,100 cP or more and 2,950 cP or less, 1,200 cP or more and 2,900 cP or less, 1,250 cP or more and 2,850 cP or less, or 1,300 cP or more and 2,800 cP or less.

[0086] The photocurable composition having a viscosity at 25°C within the above range has excellent coating properties and excellent surface quality and thickness uniformity of a coating film of the photocurable composition and a coating layer including a cured product thereof. Specifically, the total thickness variation (TTV) of the photocurable composition and a cured product thereof can be effectively reduced.

[0087] One embodiment of the present invention provides a coating layer comprising a cured product of the photocurable composition.

[0088] The coating layer according to one embodiment of the present invention has a low TTV and thus can have excellent surface quality. As described above, the photocurable composition has excellent wetting and coating properties, and the coating film of the photocurable composition can have excellent surface quality and thickness uniformity. Therefore, the coating layer formed by curing the coating film of the photocurable composition can also have excellent surface quality and thickness uniformity. In addition, the coating layer can have excellent stress relaxation performance and heat resistance.

[0089] According to one embodiment of the present invention, a UV lamp having a wavelength value of 300 nm or more and 400 nm or less is used, and 1.5 J / cm 2 ~2.0J / cm 2 The photocurable composition can be cured by irradiating it with a light amount of 10 ...

[0090] According to one embodiment of the present invention, the coating layer may have a total thickness variation (TTV), defined as the difference between the maximum thickness and the minimum thickness, of 3 μm or less, or 1 μm or more and 3 μm or less.

[0091] According to one embodiment of the present invention, the coating layer may have a total thickness deviation of 3 μm or less based on the coating direction (MD) of the photocurable composition. Specifically, the total thickness deviation of the coating layer may be 2 μm or less based on the coating direction (MD). Furthermore, the coating layer may have a total thickness deviation of 3 μm or less, or 2 μm or less based on the transverse direction (TD) perpendicular to the coating direction (MD). The coating layer, whose total thickness deviation in the coating direction (MD) and / or the transverse direction (TD) satisfies the above-mentioned ranges, may have excellent surface quality and thickness uniformity.

[0092] Throughout this specification, the coating direction (MD) of the photocurable composition is defined as the direction in which the photocurable composition is coated (applied) onto a substrate film to form the coating layer, and the transverse direction (TD) is defined as the direction perpendicular to the coating direction (MD).

[0093] According to one embodiment of the present invention, the coating layer may have a thickness of 10 μm to 100 μm. Specifically, the coating layer may have a thickness of 15 μm to 85 μm, 20 μm to 75 μm, 25 μm to 70 μm, 30 μm to 65 μm, 35 μm to 60 μm, 40 μm to 55 μm, 45 μm to 50 μm, 48 μm to 50 μm, 49 μm to 51 μm, or 53 μm to 55 μm. By adjusting the thickness of the coating layer within the above range, the stress relaxation performance and mechanical properties of the coating layer can be further improved.

[0094] According to one embodiment of the present invention, the stress relaxation rate of the coating layer may be 78% or more. Specifically, the stress relaxation rate of the coating layer may be 79% or more, or 80% or more. The stress relaxation rate of the coating layer may be 82% or less, 81% or less, or 80% or less. The stress relaxation rate of the coating layer can be measured as described in the experimental examples below. The coating layer having a stress relaxation rate within the above range can be easily applied to process films.

[0095] One embodiment of the present invention provides a process film comprising the coating layer.

[0096] A processing film according to one embodiment of the present invention has excellent stress relaxation properties and heat resistance, making it easily applicable to processing processes in various fields such as electronic control devices, semiconductors, and display panels. The processing film has excellent stress relaxation properties, making it possible to effectively protect objects from impacts that occur during processing. Specifically, the processing film including the coating layer can effectively prevent damage, warpage, and other phenomena that may occur during processing of objects. Furthermore, the processing film including the coating layer, which has excellent heat resistance, is less likely to deform or be damaged even when exposed to heat, making it easily applicable to processing processes for objects exposed to heat.

[0097] According to one embodiment of the present invention, the processing film can be used in various fields, such as a display panel processing film, a semiconductor processing film, and an electronic control device processing film.

[0098] According to one embodiment of the present invention, the process film may include a release film provided on one side of the coating layer. In this case, the coating layer may include a cured product of the photocurable composition described above. The photocurable composition may be applied to the release film and photocured to form a coating layer on the release film.

[0099] According to one embodiment of the present invention, the release film may be a polyethylene terephthalate film, a polyolefin film, an ethylene-vinyl acetate film, a polybutylene terephthalate film, a polypropylene film, or a polyethylene film, but the type of the release film is not limited thereto. The thickness of the release film may be 10 μm or more and 200 μm or less.

[0100] According to one embodiment of the present invention, the process film may further include an adhesive layer formed on the coating layer. The adhesive layer may be any adhesive layer commonly used in the art. The thickness of the adhesive layer may be 20 μm or more and 50 μm or less. [Example]

[0101] Hereinafter, the present invention will be described in detail with reference to examples. However, the examples of the present invention can be modified into various different forms, and the scope of the present invention should not be construed as being limited to the examples described below. The examples in this specification are provided to more completely explain the present invention to those skilled in the art.

[0102] The present invention will now be described in detail with reference to examples.

[0103] Manufacture of urethane (meth)acrylate resin syrup Manufacturing Example 1 A five-neck, 2-L reactor was charged with and mixed with Nippollan 963 (Tosoh), a polyalkylene carbonate polyol containing a carbonate structure containing alkylene with a methyl group attached to the side chain as a repeating unit, isophorone diisocyanate (IPDI; Evonik), hexamethylene diisocyanate (50M-HDI; Asahi Kasei), and isobornyl acrylate (IBOA; Solvay) as diisocyanate compounds to produce a first mixture. Based on 100 parts by weight of Nippollan 963, the IPDI content was approximately 13 parts by weight and the 50M-HDI content was approximately 1.4 parts by weight. The molar ratio of Nippollan 963 to IPDI was 1.0:1.25, and the molar ratio of Nippollan 963 to 50M-HDI was 4.0:1.0.

[0104] Thereafter, the first mixture was heated to 65°C and maintained at this temperature. 50 ppm of dibutyltin dilaurate (DBTDL), a tin-based catalyst, was added to induce an exothermic reaction, producing a polyalkylene carbonate-based urethane prepolymer having an isocyanate terminal group.

[0105] Then, the prepared polyalkylene carbonate-based urethane prepolymer was mixed with 2-hydroxyethyl methacrylate (2-HEMA, Nippon Shokubai Co., Ltd.), a reactive group-containing (meth)acrylate-based compound, to prepare a second mixture. -1 The disappearance of the NCO peak was confirmed to give urethane (meth)acrylate resin (A1). At this time, the content of 2-HEMA was about 1.3 parts by weight per 100 parts by weight of the polyalkylene carbonate urethane prepolymer.

[0106] Then, 2-ethylhexyl acrylate (2-EHA; LG Chemicals) as the first (meth)acrylate monomer, isobornyl acrylate (IBOA) as the second (meth)acrylate monomer, 2-hydroxyethyl acrylate (2-HEA; Nippon Shokubai) as the third (meth)acrylate monomer, O-phenylphenoxyethyl acrylate (OPPEA; M1142; Miwon Specialty) as the fourth (meth)acrylate monomer, and 2-hydroxy-3-phenoxypropyl acrylate (PGE-001; Hannon Chemicals) as the fifth (meth)acrylate monomer were added to the prepared urethane (meth)acrylate resin to prepare a urethane (meth)acrylate resin syrup.

[0107] In this case, based on 100 parts by weight of the urethane (meth)acrylate resin syrup, the content of the urethane (meth)acrylate resin was 25 parts by weight, the content of 2-EHA was 5 parts by weight, the content of IBOA was 30 parts by weight, the content of 2-HEA was 10 parts by weight, the content of OPPEA was 20 parts by weight, and the content of PGE-001 was 10 parts by weight.

[0108] The weight-average molecular weight of the produced urethane (meth)acrylate resin was 20,100 g / mol. The viscosity of the produced urethane (meth)acrylate resin syrup was about 680 cP at 25°C as measured using a Brookfield viscometer with a No. 40 spindle (rotation speed: 10 rpm).

[0109] Manufacturing Example 2 An isocyanate-terminated polyalkylene carbonate urethane prepolymer was prepared in the same manner as in Preparation Example 1, except that the content of IPDI was about 12 parts by weight and the content of 50M-HDI was about 0.5 parts by weight, based on 100 parts by weight of Nippollan 963. The molar ratio of Nippollan 963 to IPDI was 3.0:3.5, and the molar ratio of Nippollan 963 to 50M-HDI was 6.0:1.0.

[0110] Thereafter, a urethane (meth)acrylate resin (A2) was prepared in the same manner as in Preparation Example 1, except that the content of 2-HEMA was adjusted to about 0.6 parts by weight per 100 parts by weight of the polyalkylene carbonate urethane prepolymer.

[0111] Thereafter, in Preparation Example 1, based on 100 parts by weight of the urethane (meth)acrylate resin syrup, the contents of the urethane (meth)acrylate resin were adjusted to 25 parts by weight, 2-EHA to 5 parts by weight, IBOA to 20 parts by weight, 2-HEA to 10 parts by weight, OPPEA to 20 parts by weight, and PGE-001 to 20 parts by weight to prepare a urethane (meth)acrylate resin syrup.

[0112] The weight-average molecular weight of the produced urethane (meth)acrylate resin was 30,600 g / mol. The viscosity of the produced urethane (meth)acrylate resin syrup was about 1,400 cP at 25°C as measured using a Brookfield viscometer with a No. 40 spindle (rotation speed: 10 rpm).

[0113] Manufacturing Example 3 An isocyanate-terminated polyalkylene carbonate urethane prepolymer was prepared in the same manner as in Preparation Example 1, except that the content of IPDI was about 11.9 parts by weight and the content of 50M-HDI was about 0.5 parts by weight, based on 100 parts by weight of Nippollan 963. The molar ratio of Nippollan 963 to IPDI was 1.0:1.1, and the molar ratio of Nippollan 963 to 50M-HDI was 10.0:1.0.

[0114] Thereafter, a urethane (meth)acrylate resin (A3) was prepared in the same manner as in Preparation Example 1, except that the content of 2-HEMA was adjusted to about 0.4 parts by weight per 100 parts by weight of the polyalkylene carbonate urethane prepolymer.

[0115] Thereafter, in Preparation Example 1, based on 100 parts by weight of the urethane (meth)acrylate resin syrup, the contents of the urethane (meth)acrylate resin were adjusted to 25 parts by weight, 2-EHA to 5 parts by weight, IBOA to 10 parts by weight, 2-HEA to 10 parts by weight, OPPEA to 20 parts by weight, and PGE-001 to 30 parts by weight to prepare a urethane (meth)acrylate resin syrup.

[0116] The weight-average molecular weight of the produced urethane (meth)acrylate resin was 41,800 g / mol. The viscosity of the produced urethane (meth)acrylate resin syrup was about 2,700 cP at 25°C as measured using a Brookfield viscometer with a No. 40 spindle (rotation speed: 10 rpm).

[0117] [Table 1]

[0118] In Table 1, the contents of IPDI and 50M-HDI are based on 100 parts by weight of the polyalkylene carbonate polyol, and the content of 2-HEMA is based on 100 parts by weight of the polyalkylene carbonate urethane prepolymer produced.

[0119] [Table 2]

[0120] In Table 2, the contents of the urethane (meth)acrylate resin, 2-EHA, IBOA, 2-HEA, OPPEA, and PGE-001 are based on 100 parts by weight of the urethane (meth)acrylate resin syrup.

[0121] Comparative Manufacturing Example 1 A urethane prepolymer having an isocyanate terminal group was prepared in the same manner as in Preparation Example 1, except that PPG2000 (KPX), an ether-based polyol, was used instead of Nippollan 963, and the content of IPDI was adjusted to about 12 parts by weight and the content of 50M-HDI was adjusted to about 0.5 parts by weight based on 100 parts by weight of PPG2000.

[0122] Thereafter, a urethane (meth)acrylate resin (B1) was produced in the same manner as in Preparation Example 1, except that the content of 2-HEMA was adjusted to about 0.6 parts by weight per 100 parts by weight of the urethane prepolymer, and a urethane (meth)acrylate resin syrup was produced.

[0123] The weight-average molecular weight of the produced urethane (meth)acrylate resin was 31,000 g / mol. The viscosity of the produced urethane (meth)acrylate resin syrup was about 800 cP at 25°C as measured using a Brookfield viscometer with a No. 40 spindle (rotation speed: 10 rpm).

[0124] Comparative Manufacturing Example 2 A urethane prepolymer having an isocyanate terminal group was produced in the same manner as in Comparative Production Example 1, except that CAPA2201A (Perstorp), an ester-based polyol, was used instead of PPG2000.

[0125] Thereafter, a urethane (meth)acrylate resin (B2) was produced in the same manner as in Comparative Production Example 1, and a urethane (meth)acrylate resin syrup was produced.

[0126] The weight-average molecular weight of the produced urethane (meth)acrylate resin was 39,000 g / mol. The viscosity of the produced urethane (meth)acrylate resin syrup was about 4,900 cP at 25°C as measured with a Brookfield viscometer using a No. 40 spindle (at a rotation speed of 10 rpm).

[0127] Comparative Manufacturing Example 3 A urethane prepolymer having an isocyanate terminal group was prepared in the same manner as in Comparative Preparation Example 1, except that P2000 (Cray Valley), an olefin polyol, was used instead of PPG2000, and the IPDI content was adjusted to about 11.5 parts by weight and the 50M-HDI content was adjusted to about 0.5 parts by weight based on 100 parts by weight of P2000.

[0128] Thereafter, a urethane (meth)acrylate resin (B3) was produced in the same manner as in Comparative Production Example 1, and a urethane (meth)acrylate resin syrup was produced.

[0129] The weight-average molecular weight of the produced urethane (meth)acrylate resin was 39,500 g / mol. The viscosity of the produced urethane (meth)acrylate resin syrup was about 6,800 cP at 25°C as measured using a Brookfield viscometer with a No. 40 spindle (rotation speed: 10 rpm).

[0130] Comparative Manufacturing Examples 4 to 7 The urethane (meth)acrylate resin prepared in Preparation Example 2 was prepared. Then, urethane (meth)acrylate resin syrup was prepared in the same manner as in Preparation Example 2, except that the contents of the urethane (meth)acrylate resin, 2-EHA, IBOA, 2-HEA, OPPEA, and PGE-001 were adjusted as shown in Table 4 below.

[0131] [Table 3]

[0132] In Table 3, the contents of IPDI and 50M-HDI are based on 100 parts by weight of polyol, and the content of 2-HEMA is based on 100 parts by weight of the urethane prepolymer produced.

[0133] [Table 4]

[0134] In Table 4, the contents of urethane (meth)acrylate resin, 2-EHA, IBOA, 2-HEA, OPPEA, and PGE-001 are based on 100 parts by weight of urethane (meth)acrylate resin syrup. Comparative Preparation Examples 1, 2, and 3 compare the difference in resins in which the urethane acrylate has a different structure from the alkylene carbonate urethane acrylate of the Preparation Examples. Comparative Preparation Examples 4, 5, and 6 compare the difference in the content of monofunctional monomers having a benzene ring, even when using alkylene carbonate urethane acrylate resin as in the Preparation Examples.

[0135] Production of a processing film comprising a photocurable composition and a coating layer Example 1 A photocurable composition was prepared by mixing the urethane (meth)acrylate resin syrup prepared in Preparation Example 1 with a trifunctional urethane (meth)acrylate compound (GD301, LG Chemicals) represented by Formula 1-1 (R7 to R9 are hydrogen) having a weight average molecular weight of 3,500 g / mol, 1,6-hexanediol diacrylate (HDDA; M200, Miwon Specialty Co., Ltd.) as a multifunctional (meth)acrylate compound, and Irgacure #651 (BASF) as a photoinitiator. The viscosity of the photocurable composition measured as described above was approximately 850 cP at 25°C.

[0136] At this time, based on 100 parts by weight of the urethane (meth)acrylate resin contained in the urethane (meth)acrylate resin syrup, the content of the trifunctional urethane (meth)acrylate compound was 1.2 parts by weight, the content of HDDA was 0.8 parts by weight, and the content of the photoinitiator was 0.5 parts by weight.

[0137] The photocurable composition was then applied onto a PET release film having a thickness of about 150 μm using a slot die. Then, under nitrogen conditions, a UV lamp having a wavelength of 340 nm was used to apply a total light dose of 1.5 J / cm 2 . 2 The photocurable composition was cured by irradiation with light at 1000 W. This resulted in the production of a process film having a coating layer of about 50 to 52 μm in thickness formed on a PET release film.

[0138] Example 2 A coating layer and a process film including a coating layer were prepared in the same manner as in Example 1, except that the urethane (meth)acrylate resin syrup prepared in Preparation Example 2 was used instead of the urethane (meth)acrylate resin syrup prepared in Preparation Example 1.

[0139] Example 3 A coating layer and a process film including a coating layer were prepared in the same manner as in Example 1, except that the urethane (meth)acrylate resin syrup prepared in Preparation Example 3 was used instead of the urethane (meth)acrylate resin syrup prepared in Preparation Example 1.

[0140] [Table 5]

[0141] In Table 5, the contents of GD301, HDDA and photoinitiator are based on 100 parts by weight of the urethane (meth)acrylate resin contained in the urethane (meth)acrylate resin syrup.

[0142] Comparative Examples 1 to 7 A coating layer and a casting film including a coating layer were prepared in the same manner as in Example 1, except that a urethane (meth)acrylate resin syrup was used as shown in Table 6 below.

[0143] [Table 6]

[0144] In Table 6, the contents of GD301, HDDA and photoinitiator are based on 100 parts by weight of the urethane (meth)acrylate resin contained in the urethane (meth)acrylate resin syrup.

[0145] Experimental example Coating evaluation The coating properties of the photocurable compositions of Examples 1 to 3 and Comparative Examples 1 to 7 were evaluated as follows.

[0146] Specifically, the direction in which the photocurable composition is applied during the manufacturing process of the process film is defined as the coating direction (MD). When the photocurable composition is applied in the coating direction (MD) through a 15 micron filter, if the force applied to the pump using a Kawasaki gear is high, the photocurable composition will not be applied evenly due to the pump pressure, resulting in thickness deviation. The coatability was evaluated based on the following criteria, and the results are shown in Tables 7 and 8 below.

[0147] <Judgment criteria> O (Good): The force applied to the pump is 1 kgf or less △ (possible): The force applied to the pump is more than 1kgf and less than 3kgf X (Not allowed): The force applied to the pump exceeds 3 kgf

[0148] Total Thickness Variation (TTV) measurement The total thickness variation (TTV) of the coating layers prepared in Examples 1 to 3 and Comparative Examples 1 to 7 was measured as follows.

[0149] Specifically, the direction in which the photocurable composition is applied during the manufacturing process of the process film is defined as the coating direction (MD), and the direction perpendicular to the coating direction (MD) is defined as the transverse direction (TD). Next, the difference between the maximum and minimum thicknesses of the coating layer in each of the coating direction (MD) and the transverse direction (TD) was measured to calculate the total thickness deviation, and the results are shown in Tables 7 and 8 below.

[0150] Stress relaxation evaluation The stress relaxation properties of the process films produced in Examples 1 to 3 and Comparative Examples 1 to 7 were evaluated as follows.

[0151] Stress relaxation refers to the degree to which a film prevents warpage, or cracking caused by an impact on a thin film panel due to the force generated when the film is attached to a bent substrate and unable to return to its original shape. Test specimens measuring 15 mm x 100 mm x 0.05 mm (width x length x thickness) were prepared from each of the process films produced in Examples 1 to 3 and Comparative Examples 1 to 7. Stress relaxation was evaluated using a measuring device (Stable Micro Systems texture analyzer). The rate of change between the initial force (A) measured at 40% tension and the force (B) measured after 1 minute was calculated using Equation 1 below. The results are shown in Tables 7 and 8 below. [Formula 1] Stress relaxation rate (%) = (AB) / A × 100

[0152] Water dipping test A water dipping test of the process films prepared in Examples 1 to 3 and Comparative Examples 1 to 7 was carried out as follows.

[0153] Specifically, the thickness of the coating layer of the processing films prepared in Examples 1 to 3 and Comparative Examples 1 to 7 was measured, and the processing films were then completely immersed in distilled water at approximately 25°C and left for 60 minutes. The processing films were then removed and the moisture on the surface was removed. The thickness of the coating layer was then measured, and the change in thickness between the coating layer before and after immersion was calculated. The results are shown in Tables 7 and 8 below.

[0154] Thermal deformation evaluation The process films produced in Examples 1 to 3 and Comparative Examples 1 to 7 were evaluated for thermal deformation at 80° C. as follows.

[0155] Specifically, samples were prepared by attaching the coating layers of the processing films prepared in Examples 1 to 3 and Comparative Examples 1 to 7 to an 8-inch thin mirror wafer. The samples were then placed on a suction plate capable of vacuum suction and heating, and the processing film and panel were attached under vacuum. The suction plate was then heated for 30 seconds once it reached 80°C. By carrying out this process, it was possible to effectively determine whether the processing film was thermally deformed when exposed to heat when it was fully exposed to a heat source.

[0156] Thereafter, the thermal deformation was evaluated based on the following criteria, and the results are shown in Tables 7 and 8 below.

[0157] <Judgment criteria> 5 (Not occurring): No unevenness due to heat occurs on the surface of the coating layer 4: When unevenness due to heat occurs in the area between 0% and 20% of the surface of the coating layer 3: When unevenness due to heat occurs in an area between 20% and 40% of the surface of the coating layer 2: When unevenness due to heat occurs in an area between 40% and 60% of the surface of the coating layer 1: When unevenness due to heat occurs in an area between 60% and 80% of the surface of the coating layer 0 (occurs): When unevenness due to heat occurs on the entire surface (100%) of the coating layer

[0158] Film shrinkage evaluation after UV irradiation The film shrinkage evaluation of the process films manufactured in Examples 1 to 3 and Comparative Examples 1 to 7 due to UV irradiation was carried out as follows.

[0159] Test pieces measuring 150mm x 150mm x 100μm (width x length x thickness) were cut from each of the produced process films. The four sides of the film were then fixed with TESA4651 tape, and the film was cut diagonally in an X-shape with a knife to a length of 100mm x 100mm, centered on the center. The height of the film due to shrinkage was measured to evaluate the degree of shrinkage of the film after UV curing.

[0160] [Table 7]

[0161] [Table 8]

[0162] Referring to Tables 1 to 4, the urethane (meth)acrylate resins prepared in Examples 1 to 3 (Preparation Examples 1 to 3) have a relatively high weight-average molecular weight due to the inclusion of a carbonate repeating unit containing an alkylene having 1 to 10 carbon atoms to which at least one side chain having 1 to 3 carbon atoms is bonded, and the urethane (meth)acrylate resin syrups have a viscosity at 25°C within the range of 1,000 to 3,000 cPs, which is suitable for coating. This coating viscosity has the advantage that the pressure applied to the pump during coating can be uniformly adjusted to 1 kgf, allowing for a consistent supply of resin syrup to be applied through a slot die during coating, thereby reducing thickness deviation. In contrast, the (meth)acrylate resins prepared in Comparative Examples 1 to 3 (Comparative Preparation Examples 1 to 3), which do not contain the carbonate repeating unit, had similar weight-average molecular weights, but the urethane (meth)acrylate resin syrups had low or even viscosities of 3,000 cPs or more at 25° C. Thus, it is not easy to adjust the viscosity while still achieving the desired physical properties.

[0163] Referring to Tables 5 to 8, it was confirmed that the photocurable compositions according to Examples 1 to 3 of the present invention have a viscosity of 3,000 cP or less at 25°C and are excellent in coatability (especially slot die coatability). In addition, it was confirmed that the coating layers according to Examples 1 to 3 have a total thickness variation (TTV) of 3 μm or less in the coating direction (MD) and a total thickness variation (TTV) of 2 μm or less in the transverse direction (TD), thereby providing excellent surface quality and thickness uniformity.

[0164] It was also confirmed that the processing films of Examples 1 to 3 had excellent stress relaxation performance with a stress relaxation rate of 78% or more and achieved appropriate tensile strength. Furthermore, the processing films of Examples 1 to 3 had excellent heat resistance, and the results of a water immersion test and a UV irradiation film shrinkage test showed that they achieved physical properties suitable for use as processing films.

[0165] In contrast, the photocurable compositions of Comparative Examples 2 and 3 had viscosities exceeding 3,000 cP at 25°C, and Comparative Examples 3, 4, and 7 were found to have inferior coatability compared to Examples 1 to 3. Furthermore, the coating layers of Comparative Examples 2 to 4 and 7 had a total thickness variation (TTV) of 3.5 μm or more in the coating direction (MD) and a total thickness variation (TTV) of 5 μm or more in the transverse direction (TD), demonstrating poor surface quality and thickness uniformity. Furthermore, the process films of Comparative Examples 1 to 7 had very poor stress relaxation performance, with stress relaxation rates of 70% or less. In particular, the coating layers of Comparative Examples 1 to 3 were found to have very poor heat resistance.

[0166] Therefore, the photocurable composition according to one embodiment of the present invention has excellent coating properties and can realize a coating layer with excellent surface quality and thickness uniformity. Furthermore, the processing film manufactured using the photocurable composition according to one embodiment of the present invention has excellent stress relaxation rate and heat resistance, and can be easily used as a processing film in various fields.

Claims

1. a urethane (meth)acrylate resin syrup containing a urethane (meth)acrylate resin which is a reaction product of a polyalkylene carbonate urethane prepolymer having an isocyanate terminal group and a reactive group-containing (meth)acrylate compound, and a (meth)acrylate monomer mixture; Multifunctional urethane (meth)acrylate compounds; and a polyfunctional (meth)acrylate compound; The (meth)acrylate monomer mixture is The composition includes a first (meth)acrylate monomer containing an alkyl group, a second (meth)acrylate monomer containing an alicyclic alkyl group, a third (meth)acrylate monomer containing a polar functional group, a fourth (meth)acrylate monomer containing an aromatic group, and a fifth (meth)acrylate monomer containing a polar functional group and an aromatic group, The polyfunctional urethane (meth)acrylate compound includes a compound represented by the following Chemical Formula 1: [Chemical formula 1] 【Chemistry 1】 In Chemical Formula 1, R 1 , R 2 and R 3 each independently represent an alkylene group having 2 to 10 carbon atoms; R 4 , R 5 and R 6 are each independently an alkylene group having 2 to 6 carbon atoms; R 7 , R 8 and R 9 are each independently a hydrogen atom or a methyl group; n, j, and k each independently represent an integer from 1 to 3; the polyfunctional (meth)acrylate compound contains hexanediol di(meth)acrylate, the first (meth)acrylate monomer includes 2-ethylhexyl (meth)acrylate; the second (meth)acrylate monomer includes isobornyl (meth)acrylate, the third (meth)acrylate monomer includes 2-hydroxyethyl (meth)acrylate, the fourth (meth)acrylate monomer includes O-phenylphenoxyethyl (meth)acrylate, the fifth (meth)acrylate monomer includes 2-hydroxy-3-phenoxypropyl (meth)acrylate; the content of the polyfunctional urethane (meth)acrylate compound is 0.5 parts by weight or more and 2 parts by weight or less relative to 100 parts by weight of the urethane (meth)acrylate resin, the content of the polyfunctional (meth)acrylate compound is 0.5 parts by weight or more and 1.5 parts by weight or less with respect to 100 parts by weight of the urethane (meth)acrylate resin, For 100 parts by weight of the urethane (meth)acrylate resin syrup, the content of the urethane (meth)acrylate resin is 15 parts by weight or more and 35 parts by weight or less, For 100 parts by weight of the urethane (meth)acrylate resin syrup, the content of the first (meth)acrylate monomer is 2.5 parts by weight or more and 7.5 parts by weight or less, For 100 parts by weight of the urethane (meth)acrylate resin syrup, the content of the second (meth)acrylate monomer is 5 parts by weight or more and 35 parts by weight or less, For 100 parts by weight of the urethane (meth)acrylate resin syrup, the content of the third (meth)acrylate monomer is 5 parts by weight or more and 15 parts by weight or less, For 100 parts by weight of the urethane (meth)acrylate resin syrup, the content of the fourth (meth)acrylate monomer is 15 parts by weight or more and 25 parts by weight or less, For 100 parts by weight of the urethane (meth)acrylate resin syrup, The content of the fifth (meth)acrylate monomer is 5 parts by weight or more and 35 parts by weight or less. Photocurable composition.

2. The photocurable composition according to claim 1 , wherein the urethane (meth)acrylate resin has a weight average molecular weight of 20,000 g / mol or more and 50,000 g / mol or less.

3. 2. The photocurable composition according to claim 1, wherein the viscosity of the urethane (meth)acrylate resin syrup is 500 cP (equivalent to 500 mPa·s) or more and 3,000 cP (equivalent to 3,000 mPa·s) or less at 25°C.

4. The urethane (meth)acrylate resin is 2. The photocurable composition according to claim 1, comprising a carbonate repeating unit containing an alkylene having 1 to 10 carbon atoms bonded to at least one side chain having 1 to 3 carbon atoms.

5. The polyalkylene carbonate-based urethane prepolymer is 2. The photocurable composition according to claim 1, which is a reaction product of a polyalkylene carbonate polyol and a diisocyanate compound.

6. The photocurable composition according to claim 5 , wherein the content of the diisocyanate compound is 10 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the polyalkylene carbonate polyol.

7. 2. The photocurable composition according to claim 1, wherein the content of the reactive group-containing (meth)acrylate compound is 1 part by weight or more and 10 parts by weight or less per 100 parts by weight of the polyalkylene carbonate-based urethane prepolymer.

8. For 100 parts by weight of the urethane (meth)acrylate resin syrup, The photocurable composition according to claim 1 , wherein a total content of the fourth (meth)acrylate monomer and the fifth (meth)acrylate monomer is 30 parts by weight or more and 50 parts by weight or less.

9. The photocurable composition according to claim 1, wherein a weight ratio of the fourth (meth)acrylate monomer to the fifth (meth)acrylate monomer is 1:0.5 to 1:1.

5.

10. further comprising a photoinitiator; The photocurable composition according to claim 1 , wherein the content of the photoinitiator is 0.5 parts by weight or more and 3 parts by weight or less with respect to 100 parts by weight of the urethane (meth)acrylate resin.

11. 2. The photocurable composition according to claim 1, wherein the viscosity of the photocurable composition is 3,000 cP or less at 25°C (equivalent to 3,000 mPa·s).

12. A coating layer comprising a cured product of the photocurable composition according to claim 1 .

13. The coating layer according to claim 12, wherein the coating layer has a total thickness deviation, defined as the difference between the maximum thickness and the minimum thickness, of 3 μm or less.

14. A process film comprising the coating layer of claim 12.

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