TWI810431B - Curable composition for flexible hard coating - Google Patents

Abstract

The object of the present invention is to provide a curable composition capable of forming a hard coating layer with extremely high scratch resistance, hardness, elongation, flexibility and antifouling properties. The solution of the present invention is a curable composition and a hard coat film having a hard coat layer formed by the composition. The curable composition includes: (a) 100 parts by mass of an active energy ray hardening non-oxyethylene modified polyfunctional monomer, (b) 30 to 150 parts by mass of an active energy ray-curable ethylene oxide modified polyglycerin polyfunctional monomer, (c) Perfluoropolyether containing poly(oxyperfluoroalkylene) group, which is a perfluoropolyether with active energy ray polymerizable group at both ends of its molecular chain through a urethane bond (However, perfluoropolyether having a poly(oxyalkylene) group between the poly(oxyperfluoroalkylene) group and the urethane bond is not included) With respect to (a) component and (b) A total of 100 parts by mass of ingredients, 0.05 parts by mass to 10 parts by mass, and (d) The polymerization initiator which generate|occur|produces a radical by an active energy ray is 1 mass part - 20 mass parts with respect to the total 100 mass parts of (a) component and (b) component.

Description

Curable composition for flexible hard coating

The present invention relates to a curable composition useful as a material for forming a hard coat layer suitable for surfaces of various display elements such as curved touch panel displays. Specifically, it relates to a curable composition capable of forming a hard coating layer having extremely high scratch resistance, hardness, elongation, bending resistance and antifouling properties.

Used in many electronic devices such as household electrical appliances such as televisions, communication equipment such as mobile phones, office equipment such as photocopiers, entertainment equipment such as game machines, medical equipment such as X-ray imaging equipment, and household equipment such as microwave ovens. A touch panel display using a liquid crystal display element or an OLED (organic EL) display element that can be operated by someone with a finger. These touch panel displays are equipped with a transparent plastic substrate, the so-called hard coating film, which is laminated with: when a person operates with fingers, it is used to prevent damage to the surface of the touch panel due to fingernails, etc. Scratch resistance, anti-fouling properties to suppress the adhesion of fingerprints, and a hard hard coating layer to prevent deformation and damage when it comes into contact with hard objects.

On the other hand, in recent years, in order to improve the designability of the above-mentioned electronic equipment, there are cases where the above-mentioned touch panel display part is curved. When bending with the touch panel side on the outside, stress in the tensile direction occurs in the outermost hard coat layer. Therefore, the hard coat layer is required to have a certain degree of extensibility.

In general, as a method of imparting scratch resistance to the hard coat layer, for example, by forming a high-density cross-linked structure, that is, forming a cross-linked structure with low molecular mobility, the surface hardness is increased, and external force is applied. method of resistance. As a material for forming such a hard coat layer, a polyfunctional acrylate-based material that undergoes three-dimensional crosslinking by radicals is most commonly used at present. However, multifunctional acrylate-based materials are generally not extensible due to their high crosslink density. In this way, the elongation and scratch resistance of the hard coat layer are in a trade-off relationship, and it is an issue to achieve both properties. On the other hand, there is a report on the technology of hard coating layer with certain scratch resistance and elongation by using non-ethylene oxide modified multifunctional acrylate and ethylene oxide modified multifunctional acrylate ( Patent Document 1). prior art literature patent documents

Patent Document 1: Japanese Invention Patent No. 6203715

The problem to be solved by the invention

However, although the hard coat layer described in Patent Document 1 has relatively high scratch resistance and hardness, it has a problem of insufficient elongation and bendability. That is, an object of the present invention is to provide a curable composition capable of forming a hard coating layer having extremely high scratch resistance, hardness, elongation, bendability and antifouling properties. means of solving problems

In order to achieve the above object, the present inventors have repeatedly studied diligently, and as a result, found that a curable composition can form a hard coating layer having scratch resistance, hardness, elongation, bending resistance and antifouling properties, and completed the present invention Invention, the curable composition comprises perfluoropolyether, non-oxyethylene modified polyfunctional monomer and oxyethylene modified polyglycerin polyfunctional monomer, the perfluoropolyether contains poly(oxy perfluoroalkane) A perfluoropolyether with an active energy ray polymerizable group at both ends of its molecular chain is not separated by a poly(oxyalkylene) group but by a urethane bond.

That is, the first aspect of the present invention relates to a curable composition comprising: (a) 100 parts by mass of an active energy ray-curable non-oxyethylene-modified polyfunctional monomer, (b) an active energy ray-curable oxyethylene 30 to 150 parts by mass of modified polyglycerin polyfunctional monomers, (c) perfluoropolyether containing poly(oxy perfluoroalkylene) groups, which are at the two ends of its molecular chain, separated by amino methyl Ester linkages, perfluoropolyethers having active energy ray polymerizable groups (except for those having poly(oxyalkylene) groups between the poly(oxyperfluoroalkylene) group and the urethane linkage 0.05 to 10 parts by mass of perfluoropolyether) relative to the total of 100 parts by mass of (a) component and (b) component, and (d) a polymerization initiator that generates radicals by active energy rays relative to 100 mass parts of the total of (a) component and (b) component, 1 mass part - 20 mass parts. The second aspect relates to the curable composition as described in the first aspect, wherein the aforementioned (c) perfluoropolyether has at least two active energies at both ends of its molecular chain via a urethane bond. linear polymeric base. The third aspect relates to the curable composition as described in the second aspect, wherein the aforementioned (c) perfluoropolyether has at least three active energies at both ends of its molecular chain via a urethane bond linear polymeric base. The fourth viewpoint relates to the curable composition described in any one of the first viewpoint to the third viewpoint, wherein the poly(oxyperfluoroalkylene) group has a repeating unit -[OCF ₂ ]- and a repeating unit - [OCF ₂ CF ₂ ]-both, and it is a group formed by bonding these repeating units in a block bond, a random bond, or a block bond and a random bond. The fifth aspect relates to the curable composition as described in the fourth aspect, wherein the aforementioned (c) perfluoropolyether has a partial structure represented by the following formula [1]: (In the above formula [1], n is the total number of the number of repeating units -[OCF ₂ CF ₂ ]- and the number of repeating units -[OCF ₂ ]-, representing an integer of 5 to 30; the aforementioned repeating unit -[OCF ₂ CF ₂ ]- and the aforementioned repeating unit -[OCF ₂ ]- are formed by block bonding, random bonding, or any one of block bonding and random bonding). The sixth aspect relates to the curable composition as described in any one of the first aspect to the fifth aspect, wherein the average oxyethylene modified amount of the aforementioned (b) polyfunctional monomer is relative to The polymerizable group of the (b) multifunctional monomer is less than 2 mol per mol, and at the same time, it contains polyglycerol modified polyglycerol polyfunctional (meth)acrylate compounds selected from the number of functional groups of 4 or more (but, excluding oxygen Ethylene-modified polyglycerol multifunctional urethane (meth)acrylate compound) and oxyethylene modified polyglycerol multifunctional urethane (meth)acrylate compound with a functional group of 4 or more At least 1 member of the group. The seventh aspect relates to the curable composition as described in the sixth aspect, wherein the aforementioned (b) polyfunctional monomer system oxyethylene-modified diglycerol tetra(meth)acrylate. An eighth viewpoint is the curable composition as described in any one of the first viewpoint to the seventh viewpoint, which further contains (e) a solvent. A ninth aspect relates to the curable composition as described in the eighth aspect, wherein the aforementioned (e) solvent is propylene glycol monomethyl ether. A tenth aspect relates to a cured film obtained from the curable composition described in any one of the first to ninth aspects. The eleventh aspect relates to a hard coat film having a hard coat layer on at least one surface of a film substrate, and the hard coat layer includes the cured film according to the tenth aspect. The twelfth aspect relates to a hard coat film having a hard coat layer on at least one surface of a film substrate, and the hard coat layer is obtained by including the first aspect to the ninth aspect. The curable composition described in any one of the methods described above is formed by the step of applying the curable composition on a film substrate to form a coating film and the step of irradiating the coating film with active energy rays to harden it. A 13th viewpoint relates to the hard coat film as described in the 11th viewpoint or the 12th viewpoint, wherein the hard coat layer has a layer thickness of 1 μm to 10 μm. The fourteenth aspect relates to a method for producing a hard coat film, which is a method for producing a hard coat film having a hard coat layer on at least one side of a film base material, and the hard coat layer includes the following aspects of the first aspect to A step of applying the curable composition according to any one of the ninth aspects to a film substrate to form a coating film, and a step of irradiating the coating film with active energy rays to harden it. The effect of the invention

According to the present invention, it is possible to provide a curable composition capable of forming a hard coating layer having extremely high scratch resistance, hardness, elongation, flexibility and antifouling properties.

Form of implementing the invention

＜Hardening composition＞ The curable composition of the present invention relates to a curable composition in detail, which includes: (a) 100 parts by mass of an active energy ray hardening non-oxyethylene modified polyfunctional monomer, (b) 30 to 150 parts by mass of an active energy ray-curable ethylene oxide modified polyglycerin polyfunctional monomer, (c) Perfluoropolyether containing poly(oxyperfluoroalkylene) group, which is a perfluoropolyether with active energy ray polymerizable group at both ends of its molecular chain through a urethane bond (However, perfluoropolyether having a poly(oxyalkylene) group between the poly(oxyperfluoroalkylene) group and the urethane bond is not included) With respect to (a) component and (b) A total of 100 parts by mass of ingredients, 0.05 parts by mass to 10 parts by mass, and (d) The polymerization initiator which generate|occur|produces a radical by an active energy ray is 1 mass part - 20 mass parts with respect to the total 100 mass parts of (a) component and (b) component. Hereinafter, each component of said (a)-(d) is demonstrated first.

[(a) Active energy ray-curable non-oxyethylene-modified polyfunctional monomer (hereinafter, only (a) polyfunctional monomer is also described)] The so-called active energy ray hardening non-ethylene oxide modified polyfunctional monomer refers to the cured monomer that is not modified by ethylene oxide through the polymerization reaction by irradiating active energy rays such as ultraviolet rays. In the curable composition of the present invention, the preferred (a) active energy ray curable non-oxyethylene modified multifunctional monomer is selected from the group consisting of multifunctional (meth)acrylate compounds and multifunctional aminomethyl A monomer of the group consisting of ester (meth)acrylate compounds. In addition, the (meth)acrylate compound in this invention refers to both an acrylate compound and a methacrylate compound. For example, (meth)acrylic acid means acrylic acid and methacrylic acid.

Examples of the polyfunctional (meth)acrylate compound include trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol di(meth)acrylate ester, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, glycerol tri(meth)acrylate, 1 ,3-Propanediol di(meth)acrylate, 1,3-Butanediol di(meth)acrylate, 1,4-Butanediol di(meth)acrylate, 1,6-Hexanediol di(meth)acrylate (Meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate (meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate ) acrylate, tetraethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tricyclo[5.2.1.0 ^2,6 ]decanedimethanol dimethanol (Meth)acrylate, Di(meth)acrylate, 2-Hydroxy-1-acryloxy-3-methacryloxypropane, 2-Hydroxy-1,3-di (Meth)acryloxypropane, 9,9-bis[4-(meth)acryloxyphenyl]oxene, bis[4-(meth)acrylthiophenyl]sulfide, bis [2-(Meth)acrylthioethyl]sulfide, 1,3-adamantanediol di(meth)acrylate, 1,3-adamantanedimethanol di(meth)acrylate, poly Ethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, etc. Among them, as preferred polyfunctional (meth)acrylate compounds, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol hexa(meth)acrylate, (meth)acrylate, etc.

The above-mentioned polyfunctional urethane (meth)acrylate compound is one that has a plurality of acryl or methacryl groups in one molecule and has more than one urethane bond (-NHCOO-). compound. Examples of the polyfunctional urethane (meth)acrylate include those obtained by reacting a polyfunctional isocyanate with a (meth)acrylate having a hydroxyl group, and those obtained by reacting a polyfunctional isocyanate with a hydroxyl group. The reaction product of (meth)acrylate and polyhydric alcohol etc., but the polyfunctional urethane (meth)acrylate compound which can be used in this invention is not limited to this illustration.

In addition, as said polyfunctional isocyanate, toluene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate etc. are mentioned, for example. Moreover, examples of (meth)acrylates having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate, di Pentaerythritol penta(meth)acrylate, tripentaerythritol hepta(meth)acrylate, and the like. In addition, examples of the polyhydric alcohol include glycols such as ethylene glycol, propylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, and dipropylene glycol. ; Polyester polyols produced by the reaction of these diols with succinic acid, maleic acid, adipic acid and other aliphatic dicarboxylic acids or dicarboxylic anhydrides; polyether polyols; polycarbonate diols, etc.

In the present invention, as the above-mentioned (a) active energy ray-curable non-oxyethylene-modified polyfunctional monomer, the above-mentioned polyfunctional (meth)acrylate compound and the above-mentioned polyfunctional urethane (meth)acrylic acid can be In the group which consists of an ester compound, it is used individually by 1 type or in combination of 2 or more types. From the viewpoint of scratch resistance and hardness of the obtained cured product, among the above-mentioned polyfunctional monomers, a trifunctional or higher polyfunctional (meth)acrylate compound is used, preferably a tetrafunctional or higher polyfunctional (meth)acrylate compound. Meth)acrylate compounds. Moreover, in the above-mentioned (a) polyfunctional monomer, when the above-mentioned polyfunctional (meth)acrylate compound with four or more functions and a polyfunctional (meth)acrylate compound with three or less functions are used in combination, relative to the four-functional For 100 parts by mass of the above polyfunctional (meth)acrylate compound, the usage amount of the multifunctional (meth)acrylate compound with less than three functions is 10 to 100 parts by mass, preferably 20 to 60 parts by mass share. Furthermore, when using the above-mentioned polyfunctional (meth)acrylate compound and the above-mentioned polyfunctional urethane (meth)acrylate compound in combination, it is preferably In order to use 20-100 mass parts of polyfunctional urethane (meth)acrylate compounds, it is more preferable to use 30-70 mass parts.

[(b) Active Energy Ray Curable Ethylene Oxide Modified Polyglycerin Polyfunctional Monomer (Hereinafter, only (b) Polyfunctional Monomer is also described)] The so-called active energy ray-curable oxyethylene-modified polyglycerol multifunctional monomer in the curable composition of the present invention means that the polymerization reaction is carried out by irradiating active energy rays such as ultraviolet rays, and the cured monomer is modified by oxyethylene. polyglycerol polyfunctional monomer. As the above-mentioned oxyethylene-modified polyglycerin polyfunctional monomer, for example, a compound having an active energy ray polymerizable group at the end of the oxyethylene-modified polyglycerol can be mentioned.

Examples of the polyglycerin include diglycerin, triglycerin, tetraglycerin, pentaglycerin, hexaglycerol, decaglycerin, polyglycerin, and the like. From the viewpoint of scratch resistance, hardness, elongation, and bendability of the obtained cured film, diglycerin and triglycerin are preferable.

From the viewpoint of the scratch resistance, hardness, elongation and flexibility of the obtained cured film, the (b) polyfunctional mono-system functional group used in the present invention is an oxyethylene-modified polyglycerol multi-functional mono body, more preferably an oxyethylene-modified polyglycerol multifunctional monomer with 4-6 functional groups.

(b) The average oxyethylene modified mass in the polyfunctional monomer is less than 3 mol relative to 1 mol of the active energy ray polymerizable group possessed by the (b) polyfunctional monomer, preferably relative to the amount contained in the monomer. The amount of active energy ray polymerizable group contained is less than 2 mol per mol.

The number of added oxyethylenes is 1-30, preferably 1-12 per molecule of the (b) polyfunctional monomer.

Examples of the active energy ray polymerizable group in the (b) polyfunctional monomer include (meth)acryl groups, vinyl groups, and the like.

From the viewpoint of scratch resistance, hardness, elongation, and flexibility of the formed cured film, as the active energy ray-curable oxyethylene-modified polyglycerol polyfunctional monomer (b) of the present invention, oxyethylene is preferred. Modified polyglycerol multifunctional (meth)acrylate compound and oxyethylene modified polyglycerol multifunctional urethane (meth)acrylate compound. Among these compounds, oxyethylene-modified diglycerol tetra(meth)acrylate, oxyethylene-modified triglycerol tetra(meth)acrylate, oxyethylene-modified triglycerol penta(meth)acrylate are preferable. ester, more preferably oxyethylene modified diglycerol tetra(meth)acrylate compound.

In the present invention, the aforementioned (b) active energy ray-curable oxyethylene-modified polyglycerin polyfunctional monomers can be used alone or in combination of two or more.

In the present invention, relative to 100 parts by mass of the aforementioned (a) active energy ray-curable non-oxyethylene modified polyfunctional monomer, (b) the active energy ray-curable oxyethylene modified polyglycerin polyfunctional monomer is preferably 30 to 150 parts by mass, preferably 40 to 120 parts by mass.

[(c) Perfluoropolyether containing poly(oxyperfluoroalkylene) group is a perfluoropolyether having active energy ray polymerizable groups at both ends of its molecular chain through urethane bonds. Ether (but not including perfluoropolyether having a poly(oxyalkylene) group between the aforementioned poly(oxyperfluoroalkylene) group and the aforementioned urethane bond)] In the present invention, component (c) is a perfluoropolyether containing a poly(oxyperfluoroalkylene) group, and it is used at both ends of its molecular chain, not through a poly(oxyalkylene) group but through an amine group. A formate bond, a perfluoropolyether having an active energy ray polymerizable group (hereinafter also simply referred to as "(c) a perfluoropolyether having a polymerizable group at both ends of the molecular chain"). The component (c) functions as a surface modifying agent in the hard coat layer using the curable composition of the present invention. Moreover, (c) component is excellent in compatibility with (a) component and (b) component, and by this, cloudiness of a hard-coat layer is suppressed, and the hard-coat layer which shows a transparent appearance can be formed. The above-mentioned poly(oxyalkylene) group means a group in which the number of repeating units of the oxyalkylene group is 2 or more and the alkylene group in the oxyalkylene group is an unsubstituted alkylene group.

The number of carbon atoms of the alkylene group in the poly(oxyperfluoroalkylene) group is not particularly limited, but preferably 1-4 carbon atoms. That is, the above-mentioned poly(oxyperfluoroalkylene) group refers to a group having a structure in which a divalent carbon fluoride group having 1 to 4 carbon atoms and an oxygen atom are alternately linked, and an oxyperfluoroalkylene group refers to a group having a carbon The base of the structure in which a divalent fluorocarbon group with 1 to 4 atoms is linked to an oxygen atom. Specifically, -[OCF ₂ ]-(oxyperfluoromethylene), -[OCF ₂ CF ₂ ]-(oxyperfluoroethylidene), -[OCF ₂ CF ₂ CF ₂ ] -(oxyperfluoropropane-1,3-diyl), -[OCF ₂ C(CF ₃ )F]-(oxyperfluoropropane-1,2-diyl) and the like. One of the above-mentioned oxyperfluoroalkylene groups can be used alone, or two or more kinds can be used in combination. At that time, the bonding of the plural kinds of oxyperfluoroalkylene groups can be block bonding or random bonding. either.

Among them, from the viewpoint of obtaining a cured film having good scratch resistance, it is preferable to use poly(oxyperfluoroalkylene) groups having -[OCF ₂ ]-(oxyperfluoromethylene group) and -[OCF ₂ CF ₂ ]-(oxyperfluoroethylenyl) as the base of the repeating unit. Among them, as the poly(oxyperfluoroalkylene) group, it is preferable that the repeating unit: -[OCF ₂ ]- and -[OCF ₂ CF ₂ ]- become the [repeating unit: -[OCF ₂ ]- in a molar ratio. ]: [repeating unit: -[OCF ₂ CF ₂ ]-]= a base contained in a ratio of 2:1 to 1:2, more preferably a base contained in a ratio of 1:1. The linkage of these repeating units may be any of block linkage and random linkage. The number of repeating units of the above-mentioned oxyperfluoroalkylene group is preferably in the range of 5-30, more preferably in the range of 7-21. Furthermore, the poly(oxyperfluoroalkylene) group has a weight average molecular weight (Mw) of 1,000 to 5,000, preferably 1,500 to 3,000 as measured in terms of polystyrene by gel permeation chromatography (GPC). .

A (meth)acryl group, a vinyl group, etc. are mentioned as an active energy ray polymeric group bonded via the said urethane bond.

(c) Perfluoropolyethers having polymerizable groups at both ends of the molecular chain are not limited to those having active energy ray polymerizable groups such as (meth)acryl groups at both ends of one molecular chain, and may be Those having two or more active energy ray polymerizable groups at both ends of the molecular chain, for example, the terminal structures containing active energy ray polymerizable groups include the following formulas [A1] to [A5] and the structure in which the acryl group in these structures is substituted with a methacryl group.

As such (c) the perfluoropolyether which has a polymeric group at both ends of a molecular chain, the compound represented by following formula [2] is mentioned, for example. (In formula [2], A represents one of the structures represented by the aforementioned formula [A1] to formula [A5] and a structure in which the acryl group in these structures is substituted with a methacryl group, and PFPE represents the aforementioned Poly(oxyperfluoroalkylene) group (except that the side directly bonded ^{to L1} is an oxygen terminal, and the side bonded to an oxygen atom is a perfluoroalkylene terminal). a substituted alkylene group having 2 or 3 carbon atoms, m each independently represents an integer of 1 to 5, and ^L2 represents an m+1-valent residue after removing OH from an m+1-valent alcohol).

Examples of the alkylene group having 2 or 3 carbon atoms substituted with 1 to 3 fluorine atoms include -CH ₂ CHF-, -CH ₂ CF ₂ -, -CHFCF ₂ -, -CH ₂ CH ₂ CHF -, -CH ₂ CH ₂ CF ₂ , -CH ₂ CHFCF ₂ -, etc., preferably -CH ₂ CF ₂ -.

Examples of the partial structure (A-NHC(=O)O) _m L ² - in the compound represented by the above formula [2] include structures represented by the following formula [B1] to formula [B12], etc. . (Among the formulas [B1] to [B12], A represents the structures shown in the aforementioned formulas [A1] to [A5] and 1 in the structures in which the acryl group in these structures is substituted with a methacryl group. indivual). Among the structures shown in the above formula [B1] to formula [B12], formula [B1] and formula [B2] correspond to the case of m=1, and formula [B3] to formula [B6] correspond to the case of m=2 In the case, formula [B7] to formula [B9] correspond to the case of m=3, and formula [B10] to formula [B12] correspond to the case of m=5. Among these, the structure represented by formula [B3] is preferable, and the combination of formula [B3] and formula [A3] is particularly preferable.

Examples of preferred (c) perfluoropolyethers having polymerizable groups at both ends of the molecular chain include compounds having a partial structure represented by the following formula [1]. The partial structure represented by the above-mentioned formula [1] corresponds to a part obtained by removing A-NHC (=O) from the compound represented by the above-mentioned formula [2]. n in the above formula [1] represents the total number of repeating units -[OCF ₂ CF ₂ ]- and repeating units -[OCF ₂ ]-, preferably an integer in the range of 5 to 30, more preferably 7 An integer in the range of ~21. Also, the ratio of the number of the aforementioned repeating units -[OCF ₂ CF ₂ ]- to the number of the aforementioned repeating units -[OCF ₂ ]- is preferably in the range of 2:1 to 1:2, more preferably about 1:1 scope. The linkage of these repeating units may be any of block linkage and random linkage.

In the present invention, relative to the total of 100 parts by mass of the aforementioned (a) active energy ray-curable non-oxyethylene-modified polyfunctional monomer and (b) active energy ray-curable oxyethylene-modified polyglycerin polyfunctional monomer, (c) The perfluoropolyether having a polymerizable group at both ends of the molecular chain is 0.05 to 10 parts by mass, preferably 0.1 to 5 parts by mass. By using (c) perfluoropolyether having a polymerizable group at both ends of the molecular chain in a ratio of 0.05 parts by mass or more, sufficient scratch resistance and antifouling properties (water repellency and oil repellency) can be imparted to the hard coat cladding. In addition, since (c) perfluoropolyether having a polymerizable group at both ends of the molecular chain is used in a ratio of 10 parts by mass or less, it is sufficiently compatible with (a) and (b) components to obtain less cloudiness. hard coating.

The above (c) perfluoropolyether having a polymerizable group at both ends of the molecular chain can be obtained by, for example, the following formula [3] (In the formula [3], PFPE, L ¹ , L ² and m represent the same definitions as those of the aforementioned formula [2]), the hydroxyl groups present at both ends of the compound represented by the polymerizable isocyanate compound, that is, in The structure shown in the aforementioned formula [A1] to formula [A5] and the compound in which the acryl group in these structures is replaced by a methacryl group has an isocyanate group bonded to the bond (for example, 2-(methacryl group) Base) acryloxyethyl isocyanate, 1,1-bis ((meth)acryloxymethyl) ethyl isocyanate, etc.) react to form a urethane bond.

In addition, in the curable composition of the present invention, in addition to (c) perfluoropolyether containing poly(oxyperfluoroalkylene) groups, which are separated by urethane at both ends of its molecular chain Ester bond, perfluoropolyether having an active energy ray polymerizable group (provided that there is no poly(oxyalkylene) group between the aforementioned poly(oxyperfluoroalkylene) group and the aforementioned urethane bond) In addition, perfluoropolyether containing poly(oxyperfluoroalkylene) group, which is a single terminal (one terminal) of its molecular chain, which has active energy ray polymerization through a urethane bond and a perfluoropolyether having a hydroxyl group at the other end (the other end) of the molecular chain (but, between the aforementioned poly(oxyperfluoroalkylene) group and the aforementioned urethane bond and at the There is no poly(oxyalkylene) group between the aforementioned poly(oxygen perfluoroalkylene) group and the aforementioned hydroxyl group), or a perfluorinated poly(oxygen perfluoroalkylene) group containing a poly(oxygen perfluoroalkylene) group as shown in the above formula [3] Polyether, which is a perfluoropolyether having hydroxyl groups at both ends of its molecular chain (provided that it does not have a poly(oxyalkylene) group between the aforementioned poly(oxyperfluoroalkylene) group and the aforementioned hydroxyl group) [no A compound having an active energy ray polymerizing group].

The perfluoropolyether compound of the curable composition of the present invention is as described above, and has excellent compatibility with component (a), thereby suppressing cloudiness of the hard coat layer and achieving the ability to form a hard coat layer showing a transparent appearance. Excellent effect.

[(d) Polymerization initiator that generates radicals by active energy rays] In the curable composition of the present invention, a preferred polymerization initiator (hereinafter also referred to simply as "(d) polymerization initiator") that generates free radicals by active energy rays, for example, by electron rays, ultraviolet rays, Active energy rays such as , X-rays, etc., especially polymerization initiators that generate free radicals by ultraviolet radiation. Examples of the polymerization initiator (d) above include benzoins, alkylphenones, thioxanthones, azos, azides, diazos, o-quinonediazides, acyl Phosphine oxides, oxime esters, organic peroxides, diphenyl ketones, dicoumarins, bis-imidazoles, titanocenes, mercaptans, halogenated hydrocarbons, trichloromethyltrimethanones And onium salts such as iodonium salt, permeic acid salt, etc. These can be used alone or in combination of two or more. Among them, in the present invention, it is preferable to use alkylphenones as (d) the polymerization initiator from the viewpoint of transparency, surface curability, and film curability. By using alkyl phenones, a cured film having improved scratch resistance can be obtained.

Examples of the above-mentioned alkyl phenones include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 2-hydroxy-1-(4-( 2-Hydroxyethoxy)phenyl)-2-methylpropan-1-one, 2-Hydroxy-1-(4-(4-(2-Hydroxy-2-methylpropionyl)benzyl)benzene α-hydroxyalkylphenones such as )-2-methylpropan-1-one, 2-methyl-1-(4-(methylthio)phenyl)-2-morpholinopropane-1 α-aminoalkylphenones such as -ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one; 2,2-di Methoxy-1,2-diphenylethan-1-one; methyl phenylglyoxylate, etc.

In the present invention, the (d) polymerization initiator is preferably 1 to 20 parts by mass, preferably 2 to 10 parts by mass, based on 100 parts by mass of the total of the above-mentioned (a) and (b) components. Use in proportions.

[(e) vehicle] The curable composition of the present invention may further contain (e) a solvent, that is, it may be in the form of a varnish (film forming material). As the above-mentioned solvent, as long as it can dissolve the above-mentioned components (a) to (d), and consider the operability at the time of coating in the formation of the cured film (hard coat layer) described later, or the drying properties before and after curing, etc., it is appropriately selected. That's it. For example, aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, and tetralin; aliphatic or alicyclic hydrocarbons such as n-hexane, n-heptane, mineral spirits, and cyclohexane; Halogenated methyl chloride, methyl bromide, methyl iodide, dichloromethane, chloroform, carbon tetrachloride, trichloroethylene, perchlorethylene, o-dichlorobenzene, etc.; ethyl acetate, propyl acetate, butyl acetate, formazan Esters or ester ethers of oxybutyl acetate, methyl cellosuloacetate, ethyl cellosuloacetate, propylene glycol monomethyl ether acetate (PGMEA); diethyl ether , tetrahydrofuran (THF), 1,4-dioxane, methyl cellosulfur, ethyl cellosulfur, butyl cellosulfur, propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether, propylene glycol mononormal Ethers such as propyl ether, propylene glycol monoisopropyl ether, and propylene glycol mono-n-butyl ether; acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), di-n-butyl ketone, cyclic Ketones such as hexanone; alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, 2-ethylhexanol, benzyl alcohol, and ethylene glycol; Amides such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP); Substances such as disulfide (DMSO), and a mixture of two or more of these solvents. In particular, as the (e) solvent, propylene glycol monomethyl ether (PGME) is preferable.

(e) The amount of the solvent used is not particularly limited, but it is used at a concentration of 1 mass % to 70 mass %, preferably 5 mass % to 50 mass %, for example, in the curable composition of the present invention. . The so-called solid content concentration (also referred to as non-volatile matter concentration) here refers to the total mass of the above-mentioned components (a) to (e) (and other additives as desired) relative to the curable composition of the present invention. (total mass) is the content of solid content (those excluding solvent components from all components).

[other additions] In addition, in the curable composition of the present invention, within the range that does not impair the effects of the present invention, generally added additives such as polymerization accelerators, polymerization inhibitors, photosensitizers, leveling agents, etc. Agents, surfactants, adhesion imparting agents, plasticizers, ultraviolet absorbers, light stabilizers, antioxidants, storage stabilizers, antistatic agents, inorganic fillers, pigments, dyes, etc. In addition, for the purpose of controlling the haze value of the cured film, inorganic fine particles such as titanium oxide or organic fine particles such as polymethyl methacrylate particles may be blended.

＜Cured film＞ The curable composition of the present invention can be coated (coated) on a substrate to form a coating film, and the coating film is polymerized (cured) by irradiating active energy rays to form a cured film. In addition, the solvent-containing curable composition of the present invention can be coated (coated) on a substrate to form a coating film, and the solvent can be removed by heating or other methods, and the solvent can be removed by irradiating active energy rays to the substrate. The coating film of the solvent is polymerized (hardened) to form a cured film. This cured film is also an object of the present invention, and the hard coat layer in the hard coat film described later can be made of this cured film. As the base material at this time, for example, various resins (polycarbonate, polymethacrylate, polystyrene, polyethylene terephthalate (PET) or polyethylene naphthalate (PEN ) and other polyesters, polyurethanes, thermoplastic polyurethanes (TPU), polyolefins, polyamides, polyimides, epoxy resins, melamine resins, triacetyl cellulose, acrylic Nitrile-butadiene-styrene copolymer (ABS), acrylonitrile-styrene copolymer (AS), norbornene-based resin, etc.), metal, wood, paper, glass, slate, etc. The shape of these substrates may be plate-like, film-like or 3-dimensional molded body.

The coating method on the aforementioned substrate can be suitably selected from kiss coating, spin coating, knife coating, dip coating, roll coating, spray coating, bar coating, die coating, inkjet, printing, etc. method (letter printing method, gravure printing method, offset printing method, screen printing method, etc.), among them, it is suitable to use from the viewpoint of roll-to-roll (rool-to-roll) method and film coatability. Letterpress printing, especially gravure coating. In addition, it is preferable to apply the curable composition after filtering it with a filter having a pore size of about 0.2 μm or the like. In addition, at the time of coating, if necessary, a solvent may be added to the curable composition to form a varnish. Examples of the solvent at this time include various solvents listed in the aforementioned [(e) solvent]. After coating a curable composition on a base material to form a coating film, the coating film is pre-dried with heating means such as a hot plate or oven if necessary to remove the solvent (solvent removal step). As conditions of heat drying at this time, it can set it as about 40 to 120 degreeC and 30 seconds to 10 minutes, for example. After drying, the coating is cured by irradiating active energy rays such as ultraviolet rays. Examples of the active energy rays include ultraviolet rays, electron beams, X-rays, and the like, particularly preferably ultraviolet rays. As a light source for ultraviolet irradiation, sunlight, chemical lamps, low-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps, xenon lamps, UV-LEDs, and the like can be used. In addition, after that, the polymerization is completed by post-baking, specifically, by heating using heating means such as a hot plate oven. In addition, the thickness of the formed cured film after drying and curing is usually 0.01 μm to 50 μm, preferably 0.05 μm to 20 μm.

＜Hard Coating Film＞ Using the curable composition of the present invention, a hard coat film having a hard coat layer on at least one side (surface) of a film substrate can be produced. This hard coat film is also the object of this invention, and this hard coat film can be used suitably for protecting the surface of various display elements, such as a touch panel and a liquid crystal display, for example.

The hard coat layer of the hard coat film of the present invention is formed by a method comprising the steps of applying the curable composition of the present invention on a film substrate to form a coating film, and exposing ultraviolet rays to The step of irradiating the coating film with active energy rays to harden the coating film.

As the film base material, various transparent resin films that can be used for optical use among the base materials listed in the aforementioned <cured film> can be used. Examples of preferable resin films include polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN). , polyurethane, thermoplastic polyurethane (TPU), polycarbonate, polymethacrylate, polystyrene, polyolefin, polyamide, polyimide, triacetyl cellulose Etc film. In addition, the method of coating the curable composition on the above-mentioned film substrate (coating film forming step) and the method of irradiating the coating film with active energy rays (curing step) can use the methods listed in the above-mentioned <cured film> . In addition, when the curable composition of the present invention contains a solvent (in the form of varnish), after the coating film forming step, a step of drying the coating film to remove the solvent may be included if necessary. In this case, the drying method (solvent removal step) of the coating film listed in the aforementioned <cured film> can be used. The thickness of the hard coat layer thus obtained is preferably from 1 μm to 20 μm, more preferably from 1 μm to 10 μm. Example

Hereinafter, an Example is given and this invention is demonstrated more concretely, However, this invention is not limited to a following Example. In addition, in Examples, the apparatus and conditions used for the preparation of a sample and the analysis of a physical property are as follows.

(1) Coating by rod coater Device: PM-9050MC made by SMT Rod: A-Bar OSP-15 manufactured by OSG System Products Co., Ltd., with a maximum wet film thickness of 15 μm (equivalent to wire rod #6.6) Coating speed: 4m/min (2) Oven Device: Dust-free dryer DRC433FA manufactured by ADVANBTEC Toyo Co., Ltd. (3) UV hardening Device: CV-110QC-G manufactured by HERAEUS Co., Ltd. Lamp: HERAEUS Co., Ltd. high-pressure mercury lamp H-bulb (4) Gel Permeation Chromatography (GPC) Device: HLC-8220GPC manufactured by Tosoh Co., Ltd. String: Shodex (registered trademark) GPC K-804L, GPC K-805L manufactured by Showa Denko Co., Ltd. Column temperature: 40°C Eluent: Tetrahydrofuran Detector: RI (5) Scratch resistance test Device: Shinto Science Co., Ltd. reciprocating abrasion testing machine TRIBOGEAR TYPE: 30S Scanning speed: 5,000mm/min Scanning distance: 50mm (6) Tensile test Device: Desktop precision universal testing machine Autograph AGS-10kNX manufactured by Shimadzu Corporation Fixture: 1kN manual screw type flat fixture Gripping teeth: High-strength rubber-coated gripping teeth Tensile speed: 10mm/min Measuring temperature: 23°C (7) Optical microscope Device: Digital microscope VHX-6000 manufactured by KEYENCE Determination magnification: 20 times Measuring method: reflection (8) Bending test Apparatus: Cylindrical mandrel bending tester manufactured by ALLGOOD Co., Ltd. (9) Pencil hardness test Device: Yasuda Seiki Manufacturing Co., Ltd. Pencil Scratch Hardness Tester No.553-M Scratch speed: 60mm/min (10) Measurement of contact angle Device: Drop Master DM-501 manufactured by Kyowa Interface Science Co., Ltd. Measuring temperature: 20°C

Also, the abbreviations have the following meanings. A1: Non-oxyethylene modified pentaerythritol tri/tetraacrylate [Kayarad (registered trademark) PET-30 manufactured by Nippon Kayaku Co., Ltd.] EOA1: Ethylene oxide modified diglycerol tetraacrylate [Aronix (registered trademark) M-460 manufactured by Toagosei Co., Ltd., oxyethylene group 4 mol] EOA2: Ethylene oxide-modified pentaerythritol tetraacrylate [SR494NS manufactured by SARTOMER, oxyethylene group 4 mol] EOA3: Ethylene oxide-modified trimethylolpropane triacrylate [Aronix (registered trademark) M-350 manufactured by Toagosei Co., Ltd., 3 mol of oxyethylene] PFPE: Perfluoropolyether having two hydroxyl groups at both ends of the molecular chain without intervening poly(oxyalkylene) groups [Fomblin (registered trademark) T4 manufactured by SOLVAY Special Polymers Co., Ltd.] BEI: 1,1-bis(acryloxymethyl)ethyl isocyanate [Karenz (registered trademark) BEI manufactured by Showa Denko Co., Ltd.] DOTDD: Dioctyltin dineodecanoate [Neostann (registered trademark) U-830 manufactured by Nitto Kasei Co., Ltd.] O2959: 2-Hydroxy-1-(4-(2-hydroxyethoxy)phenyl)-2-methylpropan-1-one [OMNIRAD (registered trademark) 2959 manufactured by IGM Resins Co., Ltd.] PGME: Propylene Glycol Monomethyl Ether MEK: methyl ethyl ketone

[Production Example 1] Production of Surface Modifier SM 1.19 g (0.5 mmol) of PFPE1, 0.52 g (2.0 mmol) of BEI, 0.017 g of DOTDD (0.01 times the total mass of PFPE1 and BEI) and 1.67 g of MEK were added to a screw cap vial. This mixture was stirred at room temperature (about 23° C.) for 24 hours using a stirring bar to obtain a 50% by mass MEK solution of the surface modifier SM of the target compound. The weight average molecular weight of the obtained SM measured in terms of polystyrene by GPC: Mw was 3,000, and the degree of dispersion: Mw (weight average molecular weight)/Mn (number average molecular weight) was 1.2.

[Example 1-Example 3, Comparative Example 1-Comparative Example 4] According to the description in Table 1, the following components were mixed to prepare a curable composition with a solid content concentration described in Table 1. In addition, the term "solid content" here refers to components other than the solvent. In addition, in Table 1, [part] represents [part by mass]. This curable composition was coated on an A4 size double-sided easy-adhesive PET film [Toray Co., Ltd. Lumirror (trademark registration) U403, thickness 100 μm] with a bar coater to obtain a coating film. This was dried in an oven at 120°C for 3 minutes to remove the solvent. The obtained film was exposed to UV light at an exposure amount of 1200 mJ/cm ² in air to prepare a hard coat film having a hard coat layer (cured film) with a layer (film) thickness of about 2 μm.

The obtained hard coat film was evaluated for scratch resistance, elongation, bending resistance, pencil hardness and antifouling property. The procedures for evaluation of scratch resistance, elongation, bending resistance, pencil hardness and stain resistance are shown below. Table 2 shows the results together. [Scratch resistance] On the surface of the hard coat layer of the hard coat film, 200 g of steel wool [bonstar (registered trademark) #0000 (super fine)] installed in the aforementioned reciprocating abrasion tester was applied. /cm ² load, reciprocating friction 100 times, visually confirm the degree of damage, and evaluate according to the following criteria A and C. A: No damage C: Damage occurred [Extensibility] A rectangle with a length of 60 mm and a width of 10 mm was cut out from the hard coat film to prepare a test piece. Install the fixture on the aforementioned universal testing machine by grasping 20 mm from both ends of the test piece in the longitudinal direction. The elongation rate (= (increase in distance between fixtures) ÷ (distance between fixtures) × 100) becomes 2.5%, 5%, 7.5%, 10% and 2.5% intervals, the tensile test is carried out. The hard coat film after the tensile test was observed with an optical microscope, and the maximum elongation without cracking was regarded as the elongation, and evaluated according to the following criteria A and C. A: 10% or more C: Less than 10% [Bending Resistance] A rectangle having a length of 80 mm and a width of 20 mm was cut out from the hard coat film to prepare a test piece. On the aforementioned bending tester provided with a mandrel, fix the short side of the test piece so that the hard coat layer is on the outside, and bend 180 degrees for 1 to 2 seconds. The cured hard coat film was visually observed to confirm the presence or absence of cracks. The mandrels with curvature radii of 1mmR, 2mmR, 3mmR, 5mmR, and 10mmR were tested, and the minimum curvature radius without cracks was regarded as the bending resistance, and evaluated according to the following criteria A and C. A: Less than 3 mmR C: More than 3 mmR [Pencil hardness] 750 g of a pencil [manufactured by Mitsubishi Pencil Co., Ltd., hardness H] attached to the aforementioned pencil scratch hardness tester was applied to the surface of the hard coat layer of the hard coat film. The load was rubbed, and the hard coat film after the test was observed with an optical microscope, and evaluated according to the following criteria A and C. A: No damage C: Damage occurs [Anti-fouling property] 1 μL of water is attached to the surface of the hard coat layer of the hard coat film, and the contact angle θ after 5 seconds is measured at 5 points, and the average value is regarded as the contact angle Values are evaluated according to the following criteria. A: The water contact angle value is more than 110°C: The difference between the water contact angle values is less than 110°

As shown in Table 2, hard coats having hard coat layers obtained from the curable compositions of Examples 1 to 3 containing oxyethylene-modified polyglycerol tetraacrylate EOA1 as an oxyethylene-modified polyfunctional monomer Coating film exhibits excellent scratch resistance, elongation, bending resistance, pencil hardness and antifouling properties.

On the other hand, it has the curability of Comparative Example 1 and Comparative Example 2 which contain oxyethylene-modified pentaerythritol tetraacrylate EOA2 and oxyethylene-modified trimethylolpropane triacrylate EOA3 as oxyethylene-modified polyfunctional monomers. The hard coating film of the hard coating layer obtained from the composition shows poor scratch resistance, elongation and pencil hardness. Also, the hard coat film having the hard coat layer obtained from the curable composition of Comparative Example 3 that does not contain an oxyethylene-modified polyfunctional monomer exhibited poor elongation and bending resistance. Furthermore, the hard coat film having the hard coat layer obtained from the curable composition of Comparative Example 4 that does not contain the surface modifier SM exhibits poor scratch resistance and antifouling properties.

Claims (14)

A curable composition comprising: (a) an active energy ray-curable non-active energy ray selected from the group consisting of a multifunctional (meth)acrylate compound and a multifunctional urethane (meth)acrylate compound. 100 parts by mass of oxyethylene modified multifunctional monomer, (b) selected from oxyethylene modified polyglycerol multifunctional (meth)acrylate compound and oxyethylene modified polyglycerol multifunctional urethane (methyl) 30 to 150 parts by mass of active energy ray-curable oxyethylene-modified polyglycerin polyfunctional monomers composed of acrylate compounds, (c) perfluoropolymers containing poly(oxyperfluoroalkylene) groups Ether is a perfluoropolyether having a (meth)acryl group or a vinyl group as an active energy ray polymerizable group at both ends of its molecular chain through a urethane bond (except for this Perfluoropolyether having a poly(oxyalkylene) group between the poly(oxyperfluoroalkylene) group and the urethane bond) relative to 100 parts by mass of the total of (a) component and (b) component, 0.05 to 10 parts by mass, and (d) a polymerization initiator that generates radicals by active energy rays relative to 100 parts by mass of the total of (a) and (b) components, 1 to 20 parts by mass. The curable composition according to claim 1, wherein the aforementioned (c) perfluoropolyether has at least two (meth)acryl groups or vinyl. The curable composition of claim 2, wherein the aforementioned (c) perfluoropolyether has at least 3 (meth)acryl groups or vinyl. The curable composition according to any one of claims 1 to 3, wherein the aforementioned poly(oxyperfluoroalkylene) group has a repeating unit -[OCF ₂ ]- and a repeating unit -[OCF ₂ CF ₂ ]- Both of them, and it is a group formed by bonding these repeating units by block bonding, random bonding, or block bonding and random bonding. The curable composition according to claim 4, wherein the aforementioned (c) perfluoropolyether has a partial structure shown in the following formula [1]:

(In the above formula [1], n is the total number of the number of repeating units -[OCF ₂ CF ₂ ]- and the number of repeating units -[OCF ₂ ]-, representing an integer from 5 to 30; the aforementioned repeating units -[OCF ₂ CF ₂ ]- and the aforementioned repeating unit -[OCF ₂ ]- are formed by block bonding, random bonding, or any one of block bonding and random bonding). The curable composition according to any one of claims 1 to 3, wherein the average oxyethylene modified amount of the (b) polyfunctional monomer in the aforementioned (b) polyfunctional monomer system is relative to the (b) polyfunctional monomer 1 mol of the polymerizable group is less than 2 mol, and contains polyfunctional (meth)acrylate compounds selected from oxyethylene-modified polyglycerin polyglycerol polyfunctional (meth)acrylate compounds with a functional group number of 4 or more (except for oxyethylene-modified polyglycerol polyfunctional amine groups At least one member of the group consisting of formate (meth)acrylate compound) and oxyethylene-modified polyglycerin polyfunctional urethane (meth)acrylate compound with 4 or more functional groups. The curable composition as claimed in claim 6, wherein the aforementioned (b) Diglycerol tetra(meth)acrylate modified by polyfunctional monomer system oxyethylene. The curable composition according to any one of claims 1 to 3, further comprising (e) a solvent. The curable composition according to claim 8, wherein the solvent (e) is propylene glycol monomethyl ether. A cured film obtained from the curable composition according to any one of claims 1-9. A hard coating film, which is a hard coating film provided with a hard coating layer on at least one side of a film substrate, and the hard coating layer includes the cured film according to claim 10. A hard coating film, which is a hard coating film with a hard coating layer on at least one side of a film substrate, and the hard coating layer is obtained by including the hardening property according to any one of claims 1 to 9. The composition is formed by a process of applying the composition on a film substrate to form a coating film and a step of irradiating the coating film with active energy rays to harden it. The hard coat film according to claim 11 or 12, wherein the hard coat layer has a layer thickness of 1 μm to 10 μm. A method for producing a hard-coated film, which is a method for producing a hard-coated film with a hard-coated layer on at least one side of a film substrate, the hard-coated layer comprising any one of claims 1-9 The step of coating the curable composition on the film substrate to form a coating film, and the step of irradiating the coating film with active energy rays to harden it.