Multilayer film

Abstract

The present invention provides a film which is excellent in scratch resistance and also excellent in flex resistance. The present invention relates to a multilayer film which is a multilayer film having a base layer and a surface layer formed on the base layer, wherein the surface layer contains a polyurethane resin (U1) composed of an active hydrogen component (A1) and an isocyanate component (B1), the active hydrogen component (A1) contains a compound (a1) having a polyorganosiloxane group and an active hydrogen group as an essential component, and the polyurethane resin (U1) has an elastic recovery rate of 50 to 100% at 100% elongation; and the base layer contains a polyurethane resin (U2) composed of an active hydrogen component (A2) and an isocyanate component (B2), the active hydrogen component (A2) is an active hydrogen component which does not contain the compound (a1) having the polyorganosiloxane group and the active hydrogen group but contains a high-molecular polyol (a2) as an essential component, and the polyurethane resin (U2) has an elastic recovery rate of 80 to 100% at 100% elongation.

Description

Technical Field

[0001] This invention relates to a multilayer film. Background Technology

[0002] Previously, surface protective films used for optical components such as LCD panels were hard-coated films. However, although increasing the surface hardness of the film can make it less susceptible to damage, once damaged, the damage cannot be repaired.

[0003] Therefore, self-healing materials have been studied, and films made by laminating polyester urethane resins onto transparent substrates such as polyamide, polycarbonate, and polyimide have been proposed (see, for example, Patent Document 1).

[0004] However, existing technologies, including the multilayer films described in Patent Document 1, suffer from problems such as long damage recovery times and insufficient scratch resistance under conditions where micro-damage is easily formed. Furthermore, existing technologies also suffer from insufficient flexural resistance.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Publication No. 2019-511386 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The present invention was made in view of the above-mentioned problems. The objective of the present invention is to provide a membrane with excellent abrasion resistance and excellent flexural resistance.

[0010] Methods for solving problems

[0011] In order to solve the above-mentioned problems, the inventors conducted in-depth research and achieved the present invention.

[0012] That is, the present invention relates to a multilayer film having a base layer and a surface layer formed on the base layer, wherein the surface layer contains a polyurethane resin (U1) composed of an active hydrogen component (A1) and an isocyanate component (B1), wherein the active hydrogen component (A1) contains a compound (a1) having a polyorganosiloxane group and an active hydrogen group as an essential component, and the elastic recovery rate of the polyurethane resin (U1) at 100% elongation is 50-100%; the base layer contains a polyurethane resin (U2) composed of an active hydrogen component (A2) and an isocyanate component (B2), wherein the active hydrogen component (A2) is an active hydrogen component that does not contain the compound (a1) having a polyorganosiloxane group and an active hydrogen group, but contains a high molecular weight polyol (a2) as an essential component, and the elastic recovery rate of the polyurethane resin (U2) at 100% elongation is 80-100%.

[0013] The effects of the invention

[0014] The multilayer film of the present invention has excellent scratch resistance and excellent flexural resistance. Detailed Implementation

[0015] The multilayer film of the present invention is a multilayer film having a base layer and a surface layer formed on the base layer.

[0016] Furthermore, the aforementioned surface layer contains a polyurethane resin (U1) composed of an active hydrogen component (A1) and an isocyanate component (B1). The active hydrogen component (A1) contains a compound (a1) having a polyorganosiloxane group and an active hydrogen group as an essential component. The elastic recovery rate of the polyurethane resin (U1) at 100% elongation is 50-100%. The aforementioned base layer contains a polyurethane resin (U2) composed of an active hydrogen component (A2) and an isocyanate component (B2). The active hydrogen component (A2) is an active hydrogen component that does not contain the compound (a1) having the polyorganosiloxane group and an active hydrogen group, but contains a high molecular weight polyol (a2) as an essential component. The elastic recovery rate of the polyurethane resin (U2) at 100% elongation is 80-100%.

[0017] By incorporating a polyurethane resin (U1) with an active hydrogen component (A1) and an isocyanate component (B1) in its surface layer, wherein the active hydrogen component (A1) contains a compound (a1) having a polyorganosiloxane group and an active hydrogen group as an essential component, the polyurethane resin (U1) exhibits an elastic recovery rate of 50-100% at 100% elongation, thereby improving its scratch resistance.

[0018] Furthermore, by containing a polyurethane resin (U2) composed of an active hydrogen component (A2) and an isocyanate component (B2) in the base layer, wherein the active hydrogen component (A2) is an active hydrogen component that does not contain a compound (a1) having the above-mentioned polyorganosiloxane alkyl group and active hydrogen group, but contains a high molecular weight polyol (a2) as an essential component, the polyurethane resin (U2) has an elastic recovery rate of 80-100% at 100% elongation, and can be made into a film with excellent scratch resistance and flexural resistance.

[0019] In addition, the polyurethane resin (U2) and the like used in the base layer of the present invention generally have excellent scratch resistance and flexural resistance, but the surface of most of them will become sticky. By setting a surface layer in the present invention, the stickiness of the surface of the multilayer film can be suppressed.

[0020] [surface layer]

[0021] The polyurethane resin (U1), which is the main component of the surface layer, is a polyurethane resin obtained by reacting an active hydrogen component (A1) with an isocyanate component (B1). The active hydrogen component (A1) contains a compound (a1) having a polyorganosiloxane group and an active hydrogen group as an essential component.

[0022] Examples of active hydrogen components (A1) in polyurethane resin (U1) include compounds (a1) having polyorganosiloxane alkyl groups and active hydrogen groups as essential components, and optional components such as high molecular weight polyols (a2), chain extenders (a3), and reaction terminators (a4).

[0023] From the perspective of scratch resistance and haze, compounds having polyorganosiloxane groups and active hydrogen groups (a1) are preferred.

[0024] [Chemistry 1]

[0025]

[0026] R in general formula (1) 1 ~R 6 Each group independently represents a hydrocarbon group with 1 to 6 carbon atoms. As R 1 ~R 6 From the perspective of scratch resistance, alkyl groups having 1 to 3 carbon atoms are preferred, and methyl groups are even more preferred.

[0027] In general formula (1), n ​​is an integer from 1 to 100. From the perspective of scratch resistance and haze, it is preferably 10 to 70, and more preferably 15 to 50.

[0028] Examples of active hydrogen groups in compounds (a1) [hereinafter referred to as (a1)] that have polyorganosiloxane groups and active hydrogen groups include hydroxyl, amino, and carboxyl groups.

[0029] (a1) generally has low compatibility with other constituent monomers of polyurethane resin (U1). From the perspective of uniformly introducing (a1) into polyurethane resin (U1) and suppressing the increase of haze of (U1), (a1) having hydroxyl and amino groups is preferred as an active hydrogen group. (a1) can be used alone or in combination with two or more types.

[0030] In (a1), as a compound containing hydroxyl groups (a11), commercially available products can be used, such as "KF-6001" (functional group equivalent 900 g / mol), "KF-6002" (functional group equivalent 1600 g / mol), "KF-6003" (functional group equivalent 2550 g / mol) with hydroxyl groups at both ends, "X-22-1821" (functional group equivalent 1470 g / mol) (manufactured by Shin-Etsu Chemical Industry Co., Ltd.), and "BY-16-752A" (functional group equivalent 1500 g / mol) (manufactured by Toray-Dow Chemical Co., Ltd.) with phenolic hydroxyl groups at both ends. The following polyethers, manufactured by Corning Co., Ltd., contain hydroxyl groups at one end: "X-22-170BX" (functional group equivalent 2800 g / mol), "X-22-170DX" (functional group equivalent 4670 g / mol), "X-22-176DX" (functional group equivalent 1600 g / mol), and "X-22-176F" (functional group equivalent 6300 g / mol) (all manufactured by Shin-Etsu Chemical Co., Ltd.); hydroxyl groups in the branched chain: "X-22-4039" (functional group equivalent 970 g / mol) and "X-22-4015" (functional group equivalent 1870 g / mol) (all manufactured by Shin-Etsu Chemical Co., Ltd.); and hydroxyl groups in both end-terminated polyethers: "SF8427" (functional group equivalent 930 g / mol, Toray-Dow). "X-22-4952" (functional group equivalent 1100 g / mol, manufactured by Shin-Etsu Chemical Industry Co., Ltd.); "FZ-2162" (functional group equivalent 750) and "SH3773M" (functional group equivalent 800 g / mol) which have hydroxyl groups in the branched polyether (all manufactured by Toray-Dow Corning Co., Ltd.).

[0031] In (a1), as a compound containing an amino group (a12), commercially available products can be used, such as "KF-8010" (functional group equivalent 430 g / mol), "X-22-161A" (functional group equivalent 800 g / mol), "X-22-161B" (functional group equivalent 1500 g / mol), "KF-8012" (functional group equivalent 2200 g / mol), and "KF-8008" (functional group equivalent 5700 g / mol), which have amino groups at both ends. The following are listed: "X-22-9409" (functional group equivalent 700 g / mol), "X-22-1660B-3" (functional group equivalent 2200 g / mol) (all manufactured by Shin-Etsu Chemical Industry Co., Ltd.), "BY-16-853U" (functional group equivalent 460 g / mol), "BY-16-853" (functional group equivalent 650 g / mol), and "BY-16-853B" (functional group equivalent 2200 g / mol) (all manufactured by Toray-Dow Chemical Co., Ltd.). The products manufactured by Corning Co., Ltd. include "KF-868" (functional group equivalent 8800 g / mol), "KF-865" (functional group equivalent 5000 g / mol), "KF-864" (functional group equivalent 3800), "KF-880" (functional group equivalent 1800 g / mol), and "KF-8004" (functional group equivalent 1500 g / mol), which contain amino groups in their branched chains (all of which are manufactured by Shin-Etsu Chemical Co., Ltd.).

[0032] In (a1), as a compound having a carboxyl group (a13), commercially available products can be used, such as "X-22-162C" (functional group equivalent 2300 g / mol) with carboxyl groups at both ends, "X-22-3710" (functional group equivalent 1450 g / mol) with a carboxyl group at one end, and "X-22-3701E" (functional group equivalent 4000 g / mol) with a carboxyl group in the branched chain (all manufactured by Shin-Etsu Chemical Industry Co., Ltd.).

[0033] From the perspectives of scratch resistance, non-stickiness, and haze, as a constituent component, based on the weight of polyurethane resin (U1), the weight of the compound (a1) having polyorganosiloxane and active hydrogen groups in polyurethane resin (U1) is preferably 0.5 to 5% by weight, more preferably 1 to 4% by weight.

[0034] As for the high molecular weight polyol (a2), it is preferred to have a number average molecular weight (hereinafter referred to as Mn) of 500 or more. Specifically, examples include polyester polyol (a21), polyether polyol (a22), and polyether ester polyol (a23). The high molecular weight polyol (a2) can be used alone or in combination with two or more types.

[0035] Examples of polyester polyols (a21) include condensation-type polyester polyols, polylactone polyols, and polycarbonate polyols.

[0036] Examples of condensation-type polyester polyols include polyester polyols obtained by condensation of Mn or a polyol with a molecular weight of less than 500 with a polycarboxylic acid or its esterifying derivatives (such as acid anhydrides, lower (carbon number 1 to 4) alkyl esters and acyl halides).

[0037] Examples of polyols with Mn or a molecular weight less than 500 include polyols with 2 to 20 carbon atoms; alkyl epoxides (hereinafter abbreviated as AO) adducts of polyols with 2 to 20 carbon atoms having 2 to 12 carbon atoms and Mn or a molecular weight less than 500; AO adducts of bisphenols (bisphenol A, bisphenol S, and bisphenol F, etc.) having 2 to 12 carbon atoms and Mn or a molecular weight less than 500; bis(2-hydroxyethyl) terephthalate and its AO adducts having 2 to 12 carbon atoms and Mn or a molecular weight less than 500; etc.

[0038] Examples of AO with 2 to 12 carbon atoms include ethylene oxide, 1,2-epoxypropane or 1,3-epoxypropane, 1,2-epoxybutane, 1,3-epoxybutane or 2,3-epoxybutane, tetrahydrofuran, 3-methyltetrahydrofuran, styrene oxide, α-olefin oxides, and epichlorohydrin.

[0039] Examples of polyols with 2 to 20 carbon atoms include straight-chain or branched aliphatic diols with 2 to 12 carbon atoms [ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-dodecanediol, diethylene glycol, triethylene glycol, and tetraethylene glycol, etc. straight-chain alcohols; 1,2-butanediol, 1,3-butanediol or 2,3-butanediol, 2-methyl- Branched alcohols such as 1,4-butanediol, neopentyl glycol, 2,2-diethyl-1,3-propanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,6-hexanediol, 3-methyl-1,6-hexanediol, 2-methyl-1,7-heptanediol, 3-methyl-1,7-heptanediol, 4-methyl-1,7-heptanediol, 2-methyl-1,8-octanediol, 3-methyl-1,8-octanediol, and 4-methyloctanediol; carbon atoms Alicyclic diols with 6 to 20 carbon atoms [1,4-cyclohexanediol, 1,3-cyclohexanediol or 1,4-cyclohexanediol, 1,3-cyclopentanediol, 1,4-cycloheptanediol, 2,5-bis(hydroxymethyl)-1,4-dioxane, 2,7-norbornenediol, tetrahydrofurandiol, 1,4-bis(hydroxyethoxy)cyclohexane, 1,4-bis(hydroxymethyl)cyclohexane, and 2,2-bis(4-hydroxycyclohexyl)propane, etc.]; [...and others] Aromatic aliphatic diols [such as isophthalic acid or terephthalic acid, bis(hydroxyethyl)benzene and bis(hydroxyethoxy)benzene]; triols with 3 to 20 carbon atoms [such as aliphatic triols (such as glycerol and trimethylolpropane)]; tetraols to octaols with 5 to 20 carbon atoms [such as aliphatic polyols (such as pentaerythritol, sorbitol, mannitol, sorbitan, diglycerol and dipentaerythritol); sugars (sucrose, glucose, mannose, fructose, methyl glucoside and its derivatives)]; etc.

[0040] Examples of polycarboxylic acids or their esterifying derivatives with 2 to 20 carbon atoms include aliphatic dicarboxylic acids (succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, octadecanedicarboxylic acid, decylsuccinic acid, fumaric acid, and maleic acid, etc.), alicyclic dicarboxylic acids (dimer acids, etc.), aromatic dicarboxylic acids (terephthalic acid, isophthalic acid, phthalic acid, tert-butylisophthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4'-biphenyl dicarboxylic acid, etc.), trivalent or higher polycarboxylic acids (trimeric acid and benzopyrene, etc.), their anhydrides (succinic anhydride, maleic anhydride, phthalic anhydride, and trimellitic anhydride, etc.), their acyl halides (adipic chloride, etc.), their low molecular weight alkyl esters (dimethyl succinate and dimethyl phthalate, etc.), and combinations thereof.

[0041] Examples of the aforementioned polylactone polyols include those synthesized by ring-opening polymerization of lactone monomers (β-propiolactone, γ-butyrolactone, γ-valerolactone, ε-caprolactone, η-caprolactone, 11-undecanelactone, and 12-tridecane compounds, etc.) with 3 to 12 carbon atoms, using polyols with 2 to 20 carbon atoms as initiators. A single lactone monomer can be used, or two or more monomers can be used in combination.

[0042] Examples of polycarbonate polyols include those produced by condensing one or more (preferably two or four) of the above-mentioned polyols having 2 to 20 carbon atoms (preferably 3 to 9 carbon atoms, more preferably aliphatic diols having 4 to 6 carbon atoms) with low-molecular-weight carbonate compounds (e.g., dialkyl carbonates with 1 to 6 carbon atoms of alkyl groups, alkylene carbonates having 2 to 6 carbon atoms of alkylene groups, and diaryl carbonates having 6 to 9 carbon atoms of aryl groups) through a dealcoholization reaction.

[0043] Examples of polyether polyols (a22) include compounds formed by adding AO with 2 to 12 carbon atoms to the aforementioned Mn or polyols with a molecular weight of less than 500. AO can be used alone or in combination with two or more. In the latter case, it can be a block addition (tip type, balance type, active secondary type, etc.), a random addition, or a combination of these.

[0044] The addition of AO to the aforementioned Mn or polyols with a molecular weight less than 500 is carried out, for example, in the absence of a catalyst or in the presence of a catalyst (basic catalyst, amine catalyst, acid catalyst, etc.) (especially in the latter half of the AO addition stage), under normal or high pressure, in one or more stages.

[0045] Specific examples of polyether polyols (a22) include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly(oxy-3-methyltetramethylene) glycol, tetrahydrofuran / ethylene oxide copolymer glycol, and tetrahydrofuran / 3-methyltetrahydrofuran copolymer glycol.

[0046] Examples of polyether ester polyols (a23) include polyether ester polyols obtained by polycondensation of one or more of the above-mentioned polyether polyols with one or more of the polycarboxylic acids having 2 to 20 carbon atoms or their esterifying derivatives, which are the raw materials of the above-mentioned condensation-type polyester polyols.

[0047] Among the high molecular weight polyols (a2) in polyurethane resin (U1), polycarbonate polyols are particularly preferred from the perspectives of scratch resistance, non-stickiness, and chemical resistance.

[0048] From the perspective of scratch resistance, the Mn of the polymeric polyol (a2) is preferably 500 or more, more preferably 500 to 5000, and particularly preferably 800 to 3000.

[0049] It should be noted that the Mn of the high molecular weight polyol (a2) in this invention can be determined by gel permeation chromatography under conditions such as the following.

[0050] Device: "Waters Alliance 2695" [Manufactured by Waters Corporation]

[0051] The column consists of one "Guardcolumn Super HL" and one each of "TSKgel SuperH2000, TSKgel SuperH3000, and TSKgel SuperH4000 (all manufactured by Tosoh Corporation) connected together."

[0052] Sample solution: 0.25% by weight tetrahydrofuran solution

[0053] Solution injection volume: 10 μl

[0054] Flow rate: 0.6 ml / min

[0055] Measurement temperature: 40℃

[0056] Detection device: Refractive index detector

[0057] Reference material: Standard polyethylene glycol

[0058] From the perspective of scratch resistance and non-stickiness, as a constituent component, based on the weight of polyurethane resin (U1), the weight of high molecular weight polyol (a2) in polyurethane resin (U1) is preferably 50 to 90% by weight, and more preferably 60 to 80% by weight.

[0059] Examples of chain extenders (a3) ​​include water, polyols containing Mn or with a molecular weight less than 500, and polyamine compounds containing Mn or with a molecular weight less than 500.

[0060] As the polyols with Mn or a chemical formula weight of less than 500 mentioned above, the same substances with Mn or a chemical formula weight of less than 500 that constitute the condensation-type polyester polyols mentioned above can be cited.

[0061] Examples of polyamine compounds with Mn or a molecular weight less than 500 include aliphatic polyamines with 2 to 36 carbon atoms [alkylene diamines such as ethylenediamine and hexanediamine; poly(n=2 to 6) alkylene (2 to 6) poly(n=3 to 7) amines such as diethylenetriamine, dipropyltriamine, dihexyltriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and hexaneheptaethylene], alicyclic polyamines with 6 to 20 carbon atoms (1,3-cyclohexanediamine or 1,4-cyclohexanediamine, 4,4'-dicyclohexylmethanediamine or 2,4'-dicyclohexylmethanediamine and isophoronediamine), and aromatic polyamines with 6 to 20 carbon atoms (1,3-phenylenediamine or...). 1,4-phenylenediamine, 2,4-toluenediamine or 2,6-toluenediamine, 4,4'-methylenebisphenylamine or 2,4'-methylenebisphenylamine, etc.), aromatic aliphatic polyamines with 8 to 20 carbon atoms [1,3-phenylenediamine or 1,4-phenylenediamine, bis(aminoethyl)benzene, bis(aminopropyl)benzene and bis(aminobutyl)benzene, etc.], heterocyclic polyamines with 3 to 20 carbon atoms [2,4-diamino-1,3,5-triazine, piperazine and N-(2-aminoethyl)piperazine, etc.], hydrazine or its derivatives (diacid dihydrazides such as adipic acid dihydrazides, etc.) and amino alcohols with 2 to 20 carbon atoms (e.g. ethanolamine, diethanolamine, 2-amino-2-methylpropanol and triethanolamine), etc.

[0062] Among the chain extenders (a3), water, ethylene glycol, 1,4-butanediol and trimethylolpropane are preferred from the perspective of scratch resistance and non-stickiness.

[0063] From the perspective of scratch resistance and non-stickiness, as a constituent component, the weight of the chain extender (a3) ​​in the polyurethane resin (U1) is preferably 0.5 to 10% by weight, more preferably 1 to 5% by weight, based on the weight of the polyurethane resin (U1).

[0064] Examples of reaction terminators (a4) include monools with 1 to 20 carbon atoms (methanol, ethanol, butanol, octanol, decanol, dodecanol, myristol, cetyl alcohol, and stearyl alcohol, etc.) and monoamines with 1 to 20 carbon atoms (monoalkylamines or dialkylamines such as monomethylamine, monoethylamine, monobutylamine, dibutylamine, and monooctylamine, as well as monoalkylolamines or dialkylolamines such as monoethanolamine, diethanolamine, and diisopropanolamine, etc.).

[0065] Among the reaction terminators (a4), monoethanolamine and diethanolamine are preferred from the perspectives of scratch resistance and non-stickiness.

[0066] Examples of polyisocyanate components (B1) include aromatic polyisocyanates (b1) having 2 to 3 or more isocyanate groups with 8 to 26 carbon atoms, aliphatic polyisocyanates (b2) having 4 to 22 carbon atoms, alicyclic polyisocyanates (b3) having 8 to 18 carbon atoms, aromatic aliphatic polyisocyanates (b4) having 10 to 18 carbon atoms, and modified forms of these organic polyisocyanates (b5).

[0067] Examples of aromatic polyisocyanates (b1) with 8 to 26 carbon atoms (hereinafter abbreviated as (b1)) include 1,3-phenyl diisocyanate or 1,4-phenyl diisocyanate, 2,4-toluene diisocyanate or 2,6-toluene diisocyanate (hereinafter, toluene diisocyanate is abbreviated as TDI), crude TDI, 4,4'-diphenylmethane diisocyanate or 2,4'-diphenylmethane diisocyanate (hereinafter, diphenylmethane diisocyanate is abbreviated as TDI), and 4,4'-diphenylmethane diisocyanate or 2,4'-diphenylmethane diisocyanate (hereinafter, diphenylmethane diisocyanate is abbreviated as TDI). Methane diisocyanate (MDI), crude MDI, polyaryl polyisocyanates, 4,4'-diisocyanate biphenyl, 3,3'-dimethyl-4,4'-diisocyanate biphenyl, 3,3'-dimethyl-4,4'-diisocyanate diphenylmethane, 1,5-naphthalene diisocyanate, 4,4',4”-triphenylmethane triisocyanate, and m-isocyanate benzenesulfonyl isocyanate or p-isocyanate benzenesulfonyl isocyanate.

[0068] Examples of aliphatic polyisocyanates (b2) with 4 to 22 carbon atoms (hereinafter referred to as (b2)) include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (hereinafter referred to as HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanate methylhexanoate, bis(2-isocyanate ethyl) fumarate, bis(2-isocyanate ethyl) carbonate, and 2-isocyanate ethyl-2,6-diisocyanate hexanoate.

[0069] Examples of alicyclic polyisocyanates (b3) with 8 to 18 carbon atoms (hereinafter referred to as (b3)) include isophorone diisocyanate (hereinafter referred to as IPDI), 4,4'-dicyclohexylmethane diisocyanate (hereinafter referred to as hydrogenated MDI), cyclohexene diisocyanate, methylcyclohexene diisocyanate, bis(2-isocyanate ethyl)-4-cyclohexene-1,2-dicarboxylic acid ester and 2,5-norbornene diisocyanate or 2,6-norbornene diisocyanate.

[0070] Examples of aromatic aliphatic polyisocyanates (b4) with 10 to 18 carbon atoms (hereinafter abbreviated as (b4)) include isophthalimide diisocyanate, terephthalimide diisocyanate, and α,α,α',α'-tetramethylphthalimide diisocyanate.

[0071] As a modifier (b5) of the organic polyisocyanates (b1) to (b4), examples of the above-mentioned polyisocyanates containing urethane group, carbodiimide group, urea group, biuret group, urea diketone group, urea ketimide group, isocyanurate group or oxazolidinone group can be cited [e.g. modified MDI (urethane-modified MDI, carbodiimide-modified MDI and trialkyl phosphate-modified MDI, etc.), urethane-modified TDI, biuret-modified HDI, isocyanurate-modified HDI and isocyanurate-modified IPDI].

[0072] Among the isocyanate components (B1) in polyurethane resin (U1), from the perspective of scratch resistance, aromatic polyisocyanates (b1) with 8 to 26 carbon atoms are preferred, aromatic diisocyanates with 8 to 26 carbon atoms are more preferred, and MDI is particularly preferred.

[0073] Isocyanate component (B1) can be used alone or in combination with two or more.

[0074] From the perspective of scratch resistance and non-stickiness, as a constituent component, based on the weight of polyurethane resin (U1), the weight of isocyanate component (B1) in polyurethane resin (U1) is preferably 10 to 50% by weight, more preferably 20 to 40% by weight.

[0075] By adjusting the glass transition point (Tg) of the high molecular weight polyol (a2) used in the polyurethane resin (U1), the concentration of crosslinking points in the polyurethane resin (U1), and the concentrations of urethane groups and urea groups in the polyurethane resin (U1), the elastic recovery rate of the polyurethane resin (U1) can be set to a specified range.

[0076] The Tg of the high molecular weight polyol (a2) used in the polyurethane resin (U1) is preferably below -20°C, the concentration of the crosslinking point of the polyurethane resin (U1) is preferably 0.03 to 0.25 mmol / g, and the concentration of urethane groups in the polyurethane resin (U1) (the total concentration of urethane groups and urea groups in the presence of urea groups) is preferably 1.5 to 2.5 mmol / g.

[0077] It should be noted that the concentration of crosslinking points of the polyurethane resin (U1) in this invention (unit: mmol / g) is calculated by summing (F-2) × {the number of millimoles of the monomers with three or more functions in 1g of polyurethane resin (U2)} for each monomer with three or more functions, with the number of functional groups of the monomers with three or more functions set as F.

[0078] The method for manufacturing the polyurethane resin (U1) in this invention is not particularly limited, but examples include: a method of pre-manufacturing a urethane prepolymer using an active hydrogen component (A1), an isocyanate component (B1), and an organic solvent as needed, and then reacting the urethane prepolymer with a chain extender; a method of adding the active hydrogen component (A1), the isocyanate component (B1), and the organic solvent as needed into a batch reactor at once and heating them to react; etc.

[0079] There are no particular limitations on the manufacturing method of urethane prepolymers. Examples include: mixing active hydrogen component (A1) and isocyanate component (B1) in a kneader under solvent-free conditions and heating to react; or mixing active hydrogen component (A1) and isocyanate component (B1) in a batch reaction tank with a stirrer, with or without organic solvent, and heating to react.

[0080] In the manufacturing process of polyurethane resin (U1), organic solvents can be used in any of the manufacturing steps. There are no particular limitations on the organic solvents used; examples include ketone solvents with 3 to 10 carbon atoms (acetone, methyl ethyl ketone, and methyl isobutyl ketone, etc.), ester solvents with 2 to 10 carbon atoms (ethyl acetate, butyl acetate, and γ-butyrolactone, etc.), ether solvents with 4 to 10 carbon atoms (dioxane, tetrahydrofuran, ethyl cellosolve, and diethylene glycol dimethyl ether, etc.), amide solvents with 3 to 10 carbon atoms (N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and N-methylcaprolactam, etc.), sulfoxide solvents with 2 to 10 carbon atoms (dimethyl sulfoxide, etc.), alcohol solvents with 1 to 8 carbon atoms (methanol, ethanol, isopropanol, and octanol, etc.), and hydrocarbon solvents with 4 to 10 carbon atoms (cyclohexane, toluene, and xylene, etc.). Organic solvents can be used alone or in combination of two or more.

[0081] Of these, methyl ethyl ketone and toluene are preferred from the perspective of solubility.

[0082] When using an organic solvent, the amount used is preferably such that the concentration of polyurethane resin (U1) is 10 to 70% by weight, and more preferably such that the concentration of polyurethane resin (U1) is 15 to 50% by weight.

[0083] In addition, when manufacturing polyurethane resin (U1), a catalyst may be included as needed to promote the reaction. Specific examples of catalysts include organometallic compounds (dibutyltin dilaurate, dioctyltin dilaurate, bismuth carboxylate, bismuth alkoxides, and chelates of bismuth with dicarbonyl groups, etc.), inorganic metal compounds (bismuth oxide, bismuth hydroxide, bismuth halides, etc.), amines (triethylamine, triethylenediamine, and 1,8-diazabicyclo[5.4.0]-7-undecene, etc.), and combinations of two or more of them.

[0084] The surface layer contains polyurethane resin (U1) as an essential component, and may contain additives (D) such as antioxidants, ultraviolet absorbers, light stabilizers, plasticizers, adsorbents, fillers, anti-sticking agents and flame retardants as needed.

[0085] Examples of antioxidants include hindered phenolic compounds [pentaerythritol-tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, etc.], phosphorus compounds [tris(2,4-di-tert-butylphenyl)phosphite, etc.], and sulfur compounds [pentaerythritol-tetra(3-lauryl thiopropionate), dilauryl-3,3'-thiodipropionate, etc.].

[0086] Examples of benzotriazole compounds that can be used as ultraviolet absorbers include 2-(3,5-di-tert-pentyl-2-hydroxyphenyl)benzotriazole, 2-(5-methyl-2-hydroxyphenyl)benzotriazole, etc.

[0087] Examples of light stabilizers include hindered amine compounds such as (bis-2,2,6,6-tetramethyl-4-piperidinyl) sebacate.

[0088] Examples of plasticizers include phthalates (dibutyl phthalate, dioctyl phthalate, dibutyl benzyl phthalate, and diisodecyl phthalate, etc.); aliphatic diesters (di-2-ethylhexyl adipate and 2-ethylhexyl sebacate, etc.); trimellitic esters (tri-2-ethylhexyl trimellitate and trioctyl trimellitate, etc.); fatty acid esters (butyl oleate, etc.); and aliphatic phosphate esters (trimethyl phosphate, triethyl phosphate, tributyl phosphate, etc.). Tri-2-ethylhexyl phosphate and tributoxy phosphate, etc.); aromatic phosphates [triphenyl phosphate, tricresyl phosphate, tri(xyl) phosphate, toluene diphenyl phosphate, xylene diphenyl phosphate, 2-ethylhexyl diphenyl phosphate and tris(2,6-dimethylphenyl) phosphate, etc.]; halogenated aliphatic phosphates [tri(chloroethyl) phosphate, tris(β-chloropropyl) phosphate, tris(dichloropropyl) phosphate and tris(tribromoneopentyl) phosphate, etc.]; etc.

[0089] Examples of adsorbents include alumina, silica gel, and molecular sieves.

[0090] Examples of fillers include kaolin, talc, silica, titanium dioxide, calcium carbonate, bentonite, mica, sericite, glass flakes, glass fiber, graphite, magnesium hydroxide, aluminum hydroxide, antimony trioxide, barium sulfate, zinc borate, aluminum oxide, magnesium oxide, wollastonite, calcareous silica, whiskers, and metal powders.

[0091] As anti-sticking agents, known anti-sticking agents can be used, such as fluorinated compound anti-sticking agents [trifluoroalkyl (8-20 carbon atoms) phosphate esters (trifluorooctyl phosphate and trifluorododecyl phosphate, etc.)]; organosilicon compound anti-sticking agents (dimethyl polysiloxane, amino-modified dimethyl polysiloxane and carboxyl-modified dimethyl polysiloxane, etc.); fatty acid ester anti-sticking agents [monol or polyol esters of fatty acids with 10-24 carbon atoms (butyl stearate, hydrogenated castor oil and ethylene glycol monostearate, etc.)]; aliphatic amide anti-sticking agents [monamides or diamides of fatty acids with 8-24 carbon atoms (oleamide, palmitamide, stearamide and distearate of ethylenediamine, etc.)]; metal soaps (magnesium stearate and zinc stearate, etc.); natural waxes or synthetic waxes (solid paraffin wax, microcrystalline wax, polyethylene wax and polypropylene wax, etc.); etc.

[0092] Examples of flame retardants include halogen-containing flame retardants, phosphorus-containing flame retardants, antimony-containing flame retardants, and flame retardants containing metal hydroxides.

[0093] The elastic recovery rate of the polyurethane resin (U1) used in the surface layer, as determined by the method described later, is 50-100%, more preferably 60-100%. If the elastic recovery rate of the polyurethane resin (U1) is less than 50%, its abrasion resistance and flexural resistance are poor.

[0094] In polyurethane resin (U1), by setting the composition in this way, the elastic recovery rate can be adjusted to a specified value, thereby imparting abrasion resistance and flexural resistance.

[0095] [Grassroots]

[0096] In this invention, the base layer contains a polyurethane resin (U2) composed of an active hydrogen component (A2) and an isocyanate component (B2). The active hydrogen component (A2) is an active hydrogen component that does not contain a compound (a1) having a polyorganosiloxane alkyl group and an active hydrogen group, but contains a high molecular weight polyol (a2) as an essential component. The elastic recovery rate of the polyurethane resin (U2) at 100% elongation is 80-100%.

[0097] As the active hydrogen component (A2) in polyurethane resin (U2), it does not contain compounds (a1) with polyorganosiloxane alkyl groups and active hydrogen groups, but contains high molecular weight polyols (a2) as an essential component.

[0098] Polyurethane resin (U2) has excellent transparency because it does not contain compounds with active hydrogen groups (a1). By including high molecular weight polyol (a2) as an essential component, it can be adjusted to a specified elastic recovery rate, thus imparting scratch resistance and flexural resistance.

[0099] It should be noted that the compounds (a1) and high molecular weight polyols (a2) containing polyorganosiloxane and active hydrogen groups mentioned above refer to the compounds (a1) and high molecular weight polyols (a2) containing polyorganosiloxane and active hydrogen groups described in polyurethane resin (U1).

[0100] From the perspective of adjusting the elastic recovery rate to a specified range and appropriately imparting abrasion resistance and flexural resistance, the polymeric polyol (a2) preferably includes a polyether polyol (a22), more preferably includes polytetramethylene glycol, poly(oxy-3-methyltetramethylene) glycol and tetrahydrofuran / 3-methyltetrahydrofuran copolymer diol, and particularly preferably includes polytetramethylene glycol.

[0101] From the perspective of scratch resistance, the Mn of the polymeric polyol (a2) is preferably 500 or more, more preferably 500 to 5000, and particularly preferably 800 to 4000.

[0102] From the perspective of scratch resistance and flexural resistance, as a constituent component, based on the weight of polyurethane resin (U2), the weight of high molecular weight polyol (a2) in polyurethane resin (U2) is preferably 60 to 90% by weight, and more preferably 70 to 85% by weight.

[0103] The active hydrogen component (A2) may contain chain extenders and reaction terminators as optional components.

[0104] As the chain extender mentioned above, the chain extender (a3) ​​described in polyurethane resin (U1) can be appropriately selected.

[0105] In addition, the reaction terminator described in polyurethane resin (U1) (a4) can be appropriately selected as the reaction terminator mentioned above.

[0106] From the perspective of scratch resistance and flexural resistance, as a constituent component, based on the weight of polyurethane resin (U2), the weight of chain extender (a3) ​​in polyurethane resin (U2) is preferably 0.5 to 20% by weight, more preferably 1 to 10% by weight.

[0107] As the polyisocyanate component (B2), the polyisocyanate component (B1) described in the polyurethane resin (U1) may be appropriately selected for use.

[0108] From the perspective of scratch resistance, aromatic polyisocyanates with 8 to 26 carbon atoms (b1) are preferred, aromatic diisocyanates with 8 to 26 carbon atoms are further preferred, and MDI is particularly preferred.

[0109] From the perspective of scratch resistance and flexural resistance, as a constituent component, based on the weight of polyurethane resin (U2), the weight of the polyisocyanate component (B2) in polyurethane resin (U2) is preferably 5 to 40% by weight, more preferably 10 to 30% by weight.

[0110] By adjusting the glass transition point (Tg) of the high molecular weight polyol (a2) used in the polyurethane resin (U2), the concentration of crosslinking points in the polyurethane resin (U2), and the concentrations of urethane groups and urea groups in the polyurethane resin (U2), the elastic recovery rate of the polyurethane resin (U2) can be set to a specified range.

[0111] The Tg of the high molecular weight polyol (a2) used in the polyurethane resin (U2) is preferably below -20°C, the concentration of the crosslinking point of the polyurethane resin (U2) is preferably 0.05 to 0.25 mmol / g, and the concentration of urethane groups in the polyurethane resin (U2) (the total concentration of urethane groups and urea groups in the presence of urea groups) is preferably 1.0 to 2.0 mmol / g.

[0112] It should be noted that the concentration of the crosslinking point of the polyurethane resin (U2) in this invention (unit: mmol / g) is calculated by summing (F-2) × {the number of millimoles of polyurethane resin (U2) with three or more functional monomers used in the polyurethane resin (U2)}, with the number of functional groups of the monomers with three or more functional monomers set as F.

[0113] The manufacturing method of the polyurethane resin (U2) in this invention is not particularly limited. Except for containing active hydrogen component (A2) and isocyanate component (B2), the same method as the manufacturing method of polyurethane resin (U1) can be used.

[0114] In addition, when manufacturing polyurethane resin (U2), the catalyst used in the manufacturing method of polyurethane resin (U1) may be included as needed to promote the reaction.

[0115] The base layer contains polyurethane resin (U2) as an essential component, and may contain the additives (D) used in the manufacturing method of polyurethane resin (U1) as needed.

[0116] The polyurethane resin (U2) used in the base layer functions to quickly recover from deformation caused by external pressure in the multilayer film of the present invention; therefore, its elastic recovery rate at 100% elongation needs to be 80-100%. The elastic recovery rate of the polyurethane resin (U2) is preferably 85-100%, more preferably 90-100%, and particularly preferably 95-100%. If the elastic recovery rate at 100% elongation is less than 80%, sufficient abrasion resistance and flexural strength cannot be imparted.

[0117] The elastic recovery rate at 100% elongation in this invention is determined by the following method.

[0118] <Method for determining elastic recovery rate at 100% elongation>

[0119] (1) Cut a strip of test piece 100mm long and 5mm wide from a sheet with a film thickness of about 2mm, and draw the markings with a spacing of 50mm between the markings.

[0120] (2) Place the test piece in the clamp of an INSTRON type tensile testing machine (Autograph manufactured by Shimadzu Corporation) and perform the following operation: elongate it at a constant speed of 500 mm / min in an atmosphere of 25°C until the distance between the marks is 100%, and then immediately restore it to the distance between the clamps before elongation at the same speed.

[0121] (3) Measure the stress (M1) at 50% elongation during the elongation process and the stress (M2) at 50% elongation during the recovery process during the operation, and calculate the elastic recovery rate using the following formula.

[0122] Elastic recovery rate (%) = M2 / M1 × 100

[0123] [Multilayer film]

[0124] The multilayer film of the present invention has a base layer and a surface layer formed on the base layer.

[0125] From the perspective of scratch resistance and anti-adhesion, the thickness of the surface film is preferably 1 to 50 μm, and more preferably 5 to 25 μm.

[0126] From the perspective of scratch resistance and flexural resistance, the thickness of the base layer is preferably 100-1000 μm, and more preferably 300-600 μm.

[0127] The multilayer film of the present invention is preferably used as a surface protective film for optical components. To impart adhesion to the optical components, an adhesive layer can be provided on the substrate side as needed. As the aforementioned adhesive layer, a known adhesive layer can be appropriately selected.

[0128] The manufacturing method of the multilayer film of the present invention is not particularly limited, and for example, it can be manufactured using the following methods.

[0129] (1) Manufacturing process of polyurethane resin (U1) prepolymer used in the surface layer

[0130] A polyurethane prepolymer for polyurethane resin (U1) with isocyanate groups at the end is produced by reacting a compound (a1) having polyorganosiloxane and active hydrogen groups, a high molecular weight polyol (a2), and an isocyanate component (B1) in an organic solvent as needed.

[0131] (2) Manufacturing process of polyurethane resin (U2) prepolymer used in the base layer

[0132] A polyurethane prepolymer for polyurethane resin (U2) with isocyanate groups at the end is produced by reacting a high molecular weight polyol (a2) with an isocyanate component (B2) in an organic solvent as needed.

[0133] (3) Surface formation process

[0134] The polyurethane resin (U1) is mixed with a urethane prepolymer or its organic solvent solution, as needed, with a high molecular weight polyol (a2) and / or a chain extender (a3), and then coated onto the release film to the specified film thickness. It should be noted that, in the case of using organic solvents, the organic solvents should be dried.

[0135] (4) Formation process of the base layer

[0136] Polyurethane resin (U2) is mixed with a urethane prepolymer or its organic solvent solution and a chain extender (a3). The mixture is then coated onto the surface layer obtained in (3) to a specified film thickness and heated to cure, thus forming a base layer. It should be noted that when using an organic solvent, drying is performed simultaneously with curing.

[0137] Through the above processes (1) to (4), a multilayer film with a surface layer and a base layer is formed on the anti-stick film.

[0138] The temperature of the urethane prepolymerization reaction in the above-mentioned processes (1) and (2) is not particularly limited, but is preferably 50 to 140°C, more preferably 70 to 100°C. In addition, the reaction time is not particularly limited, but is preferably 1 to 10 hours, more preferably 2 to 8 hours.

[0139] The drying temperature in the above (3) process is not particularly limited, but is preferably 30 to 80°C, and more preferably 40 to 60°C. The drying time is not particularly limited, but is preferably 10 seconds to 5 minutes, and more preferably 20 to 60 seconds.

[0140] The curing temperature in step (4) above is not particularly limited, but is preferably 60-150°C, more preferably 80-120°C. The curing time is not particularly limited, but is preferably 1-8 hours, more preferably 2-6 hours. It should be noted that the drying of the organic solvent in step (4) above, which is performed as needed, is carried out simultaneously with the curing process described above.

[0141] Example

[0142] The present invention will be specifically described below through embodiments, but the present invention is not limited to these embodiments. It should be noted that the parts referred to below are parts by weight.

[0143] <Manufacturing Example 1> [Manufacturing of the polyurethane resin (U1-1) used in the surface layer using urethane prepolymer]

[0144] Compounds containing polyorganosiloxane and active hydrogen (a1), high molecular weight polyol (a2), aromatic polyisocyanate (b1), modified organic polyisocyanate (b5), and organic solvent, as shown in Table 1 (parts by weight), were added to a container equipped with a stirrer and a temperature control device. The mixture was reacted at 80°C for 3 hours to obtain a urethane prepolymer for polyurethane resin (U1-1). The NCO content of the obtained urethane prepolymer was 1.46%.

[0145] <Manufacturing Examples 2-6 and Comparative Manufacturing Examples 1-2> [Manufacturing of urethane prepolymers for polyurethane resins (U1-2)-(U1-5), (U1'-1)-(U1'-2) used in the surface layer]

[0146] Except for changing the raw materials and their amounts (parts by weight) as shown in Table 1, the same procedure as in Manufacturing Example 1 was carried out to obtain urethane prepolymers of polyurethane resins (U1-2) to (U1-6) used for the surface layer and urethane prepolymers of polyurethane resins (U1'-1) to (U1'-2) used for comparison.

[0147] [Determination of the elastic recovery rate of the polyurethane resin (U1-1) used in the surface layer]

[0148] In a polypropylene beaker, the urethane prepolymer (U1-1) obtained in Manufacturing Example 1 was mixed with the chain extender (a3) ​​according to the formulation described in Table 1. The resulting mixture was poured into an 11 × 17.5 cm polypropylene pan, dried to a thickness of 200 μm, and dried at room temperature overnight. After drying, it was cured at 120°C for 2 hours to obtain a sheet of polyurethane resin (U1-1) used for the surface layer.

[0149] Using this piece, the elastic recovery rate was determined based on the method described above for measuring the elastic recovery rate at 100% elongation. The results are shown in Table 1.

[0150] [Determination of elastic recovery rate of polyurethane resins (U1-2) to (U1-6) used in the surface layer and polyurethane resins (U1'-1) to (U1'-2) used in comparison]

[0151] Except for changing the urethane prepolymer and chain extender (a3) ​​used and their amounts (parts by weight) as shown in Table 1, the same procedure was performed as in Test Example 1 to obtain sheets of polyurethane resin (U1-2) to (U1-6) used for the surface layer and polyurethane resin (U1'-1) to (U1'-2) used for comparison.

[0152] Using this piece, the elastic recovery rate was determined based on the method described above for measuring the elastic recovery rate at 100% elongation. The results are shown in Table 1.

[0153] It should be noted that the contents of the various raw materials recorded in Table 1 are as follows.

[0154] Materials for polyurethane resins using urethane prepolymers

[0155] [Compounds containing polyorganosiloxane alkyl groups and active hydrogen groups (a1)]

[0156] ·X-22-161A: Amino-modified silicone oil [Mn=1600, R in general formula (1)] manufactured by Shin-Etsu Chemical Co., Ltd. 1 ~R 6 =Methyl, n=22]

[0157] ·KF-6003: Hydroxyl-modified silicone oil manufactured by Shin-Etsu Chemical Co., Ltd. [Mn = 5100, R in general formula (1)] 1 ~R 6 =Methyl, n=68]

[0158] [Polyol (a2)]

[0159] • KURARAY Polyol C1090: Polycarbonate polyol (Mn: 1000) manufactured by KURARAY Corporation.

[0160] [Aromatic polyisocyanate (b1)]

[0161] ·4,4'-MDI: MillionateMT manufactured by Tosoh Corporation

[0162] [Modified organic polyisocyanates (b5)]

[0163] CORONATE 2793: A polyisocyanate containing urea-formyl groups manufactured by Tosoh Corporation (average number of functional groups = 5.1).

[0164] [Organic solvents]

[0165] Toluene

[0166] Materials for chain extension reactions of urethane prepolymers

[0167] [Chain extender (a3)]

[0168] ·1,4-Butanediol

[0169] Trimethylolpropane

[0170] [Organic solvents]

[0171] ·Methyl ethyl ketone

[0172] In addition, the “Materials for chain extension reaction of urethane prepolymers” column in Table 1 records the materials and their amounts used when chain extending each prepolymer used in the examples described later.

[0173] [Table 1]

[0174]

[0175] <Manufacturing Example 7> [Manufacturing of urethane prepolymer for polyurethane resin (U2-1) used in the base layer]

[0176] The types and amounts (parts by weight) of high molecular weight polyol (a2) and aromatic polyisocyanate (b1) shown in Table 2 were added to a container equipped with a stirring device and a temperature control device, and reacted at 80°C for 3 hours to obtain a urethane prepolymer for polyurethane resin (U2-1). The NCO content of the obtained urethane prepolymer was 3.36%.

[0177] [Manufacturing of urethane prepolymers for polyurethane resins (U2-2) to (U2-8), (U2'-1) to (U2'-2) used in the base layer]

[0178] Except for changing the urethane prepolymer used and its amount (parts by weight) as shown in Table 2, the same procedure as in Manufacturing Example 7 was carried out to obtain urethane prepolymers for polyurethane resins (U2-2) to (U2-8) used in the surface layer and urethane prepolymers for polyurethane resins (U2'-1) to (U2'-2) used in comparison.

[0179] It should be noted that the contents of the various raw materials represented by symbols or trade names in Table 2 are as follows.

[0180] Materials for polyurethane resins using urethane prepolymers

[0181] [Polyol (a2)]

[0182] •PTMG-1000: Polytetramethylene glycol (Mn=1000) manufactured by Mitsubishi Chemical Corporation

[0183] PTMG-2000: Polytetramethylene glycol (Mn=2000) manufactured by Mitsubishi Chemical Corporation.

[0184] •PTMG-3000: Polytetramethylene glycol (Mn=3000) manufactured by Mitsubishi Chemical Corporation

[0185] •PRAXCELL220: Polycaprolactone diol (Mn=2000) manufactured by Daicel Corporation.

[0186] [Polyols with Mn less than 500]

[0187] • Sanix PP-400: Polypropylene glycol (Mn=400) manufactured by Sanyo Chemical Industries, Ltd.

[0188] [Aromatic polyisocyanate (b1)]

[0189] • 4,4'-MDI: Millionate MT manufactured by Tosoh Corporation

[0190] Materials for chain extension reactions of urethane prepolymers

[0191] [Chain extender (a3)]

[0192] ·1,4-Butanediol

[0193] Trimethylolpropane

[0194] In addition, the “Materials for chain extension reaction of urethane prepolymers” column in Table 2 records the materials and their amounts used when chain extending each prepolymer used in the test examples and examples described later.

[0195] [Determination of the elastic recovery rate of the polyurethane resin (U2-1) used in the substrate]

[0196] In a polypropylene beaker, the polyurethane resin (U2) obtained in Manufacturing Example 7, preheated to 80°C, was mixed with urethane prepolymer and chain extender (a3) ​​according to the formulation described in Table 2. After stirring for 1 minute, the mixture was degassed under reduced pressure for 2 minutes. The resulting mixture was cast into a SUS metal mold with a 2 mm gap and cured at 120°C for 2 hours to obtain a sheet of polyurethane resin (U2-1) used as the base layer.

[0197] The concentrations of crosslinking points and urethane group concentrations of polyurethane resin (U2-1) are shown in Table 2.

[0198] Using this piece, the elastic recovery rate was determined based on the method described above for measuring the elastic recovery rate at 100% elongation. The results are shown in Table 2.

[0199] [Determination of elastic recovery rate of polyurethane resins (U2-2) to (U2-8) used in the base layer and polyurethane resins (U2'-1) to (U2'-2) used for comparison]

[0200] Except for changing the urethane prepolymer and chain extender (a3) ​​used and their amounts (parts by weight) as shown in Table 2, the same procedure was carried out as in Test Example 7, and sheets of polyurethane resin (U2-2) to (U2-8) used for the base layer and polyurethane resin (U2'-1) to (U2'-2) used for comparison were obtained.

[0201] The concentrations of crosslinking points and urethane group concentrations of polyurethane resins (U2-2) to (U2-8) and comparative polyurethane resins (U2'-1) to (U2'-2) are shown in Table 2.

[0202] Using these sheets, the elastic recovery rate was determined based on the method described above for measuring the elastic recovery rate at 100% elongation. The results are shown in Table 2.

[0203] [Determination of the elastic recovery rate of the comparative polyurethane resin (U2'-3) used in the base layer]

[0204] 150 parts of the polyether-based thermoplastic urethane elastomer "Elastollan 1180A" (manufactured by BASF Japan Co., Ltd.) were added to a container equipped with a stirrer and temperature control device containing 350 parts of toluene under stirring, and the mixture was heated to 80°C to dissolve it. The resulting mixture was poured into an 11×17.5cm polypropylene pan, dried to a thickness of 400μm, and dried at room temperature overnight. It was then further dried in a vacuum dryer at 100°C for 2 hours to obtain a sheet of comparative polyurethane resin (U2'-3) used for the base layer.

[0205] Using this piece, the elastic recovery rate was determined based on the method described above for measuring the elastic recovery rate at 100% elongation. The results are shown in Table 2.

[0206]

[0207] <Example 1> [Manufacturing of Multilayer Films]

[0208] The polyurethane resin (U1-1) for surface coating obtained in Manufacturing Example 1 was mixed with 496.1 parts of urethane prepolymer (total amount of urethane prepolymer material listed in Table 1) and 7.6 parts of 1,4-butanediol and 496.3 parts of methyl ethyl ketone, which are materials for chain extension reaction of urethane prepolymer listed in Table 1. The mixture was coated onto an anti-stick film, and the film thickness after drying was 10 μm. The film was then dried in a circulating air dryer at 50°C for 30 seconds to evaporate the solvent, thus producing the polyurethane resin for surface coating.

[0209] The polyurethane resin (U2-1) obtained in Manufacturing Example 7 was mixed with urethane prepolymer and chain extender (a3) ​​according to the formulation recorded in Table 2, and coated onto the surface polyurethane resin to make the film thickness 400 μm. After curing at 120°C for 2 hours, the release film was peeled off to obtain a multilayer film with polyurethane resin (U1-1) as the surface layer and polyurethane resin (U2-1) as the base layer.

[0210] <Examples 2-19 and Comparative Examples 1-4>

[0211] Except for changing the polyurethane resin used for the surface layer and the polyurethane resin used for the base layer to the combination described in Table 3, the process was carried out in the same manner as in Example 1 to obtain the multilayer films of Examples 2 to 19 and Comparative Examples 1 to 4.

[0212] <Comparative Example 5>

[0213] The polyurethane resin (U1-1) for surface layer obtained in the same manner as in Example 1 was coated with urethane prepolymer onto a sheet of polyurethane resin (U2'-3) with a thickness of 400 μm obtained in the same manner as in Comparative Example 5, so that the film thickness after drying is 10 μm. The film was dried in a circulating air dryer at 50°C for 30 seconds and then cured at 120°C for 2 hours to obtain the multilayer film of Comparative Example 5.

[0214] The scratch resistance of the obtained multilayer film was evaluated using the following evaluation method, and the results are shown in Table 3.

[0215] [Evaluation method for abrasion resistance]

[0216] Steel wool (No. 0000) manufactured by Japan Steel Wool Co., Ltd. was installed onto the "TriboGear Model: 40" steel wool fixing clamp manufactured by Shin-To Science Co., Ltd., at 1cm intervals. 2 A load of 100g was applied, and the number of reciprocating rubs required to damage the surface side of the multilayer films obtained in the examples and comparative examples was observed when a 5cm length was repeatedly rubbed. The evaluation was based on the following criteria. The results are shown in Table 3.

[0217] <Evaluation Criteria>

[0218] ◎: No damage will occur after more than 500 repetitions.

[0219] ○: Damage occurs when there are more than 300 reciprocating cycles but less than 500 reciprocating cycles.

[0220] ×: Damage will occur if the number of cycles is less than 300.

[0221] [Evaluation methods for flexural resistance]

[0222] For the multilayer films obtained in the examples and comparative examples, samples with dimensions of 50 mm in the width direction (direction of the folds) and 100 mm in the flow direction (bending direction) were prepared. Using a no-load U-shaped stretching tester (manufactured by Yuasa System Equipment, DLDMLH-FS), the bending radius was set to 3 mm, and the sample was bent 50,000 times at a rate of 1 time / second. At this time, the sample was fixed 10 mm from both ends of the long side, and the bending area was set to 50 mm × 80 mm. After the bending process, the sample was placed on a flat surface with the bent inner side facing down for visual inspection.

[0223] <Evaluation Criteria>

[0224] ◎: The sample is not deformed; or, even if it is deformed, the maximum height of the bulge is less than 3mm when placed horizontally.

[0225] ○: The sample is deformed. When placed horizontally, the maximum height of the bulge is more than 3 mm but less than 5 mm.

[0226] ×: The sample has creases; or, when placed horizontally, the maximum height of the bulge is more than 5mm.

[0227] [Table 3]

[0228]

[0229] Industrial applicability

[0230] The polyurethane resin of the present invention has excellent scratch resistance and excellent flexural resistance, and is therefore suitable for use as a surface protective film for optical components, especially for touch devices.

Claims

1. A multilayer film having a base layer and a surface layer formed on said base layer, wherein, The surface layer contains a polyurethane resin U1 composed of an active hydrogen component A1 and an isocyanate component B1. The active hydrogen component A1 contains a compound a1 with polyorganosiloxane alkyl groups and active hydrogen groups as an essential component. The polyurethane resin U1 has an elastic recovery rate of 50% to 100% at 100% elongation. The base layer contains polyurethane resin U2 composed of active hydrogen component A2 and isocyanate component B2. The active hydrogen component A2 is an active hydrogen component that contains a high molecular weight polyol a2 as an essential component, but does not contain compound a1 having the aforementioned polyorganosiloxane alkyl group and active hydrogen group. The elastic recovery rate of the polyurethane resin U2 at 100% elongation is 80%–100%. The thickness of the surface layer is 1 μm to 50 μm, and the thickness of the base layer is 100 μm to 1000 μm. Based on the weight of the polyurethane resin U1, the compound a1 having polyorganosiloxane and active hydrogen groups is 0.5% to 5% by weight as a constituent component.

2. The multilayer film as described in claim 1, wherein, The polyorganosiloxane is the polyorganosiloxane represented by general formula (1). In the formula, R 1 ~R 6 Each group independently represents a hydrocarbon group with 1 to 6 carbon atoms, where n is an integer from 1 to 100.

3. The multilayer film as described in claim 1 or 2, wherein, The high molecular weight polyol a2 is a high molecular weight polyol containing polytetramethylene glycol.

4. The multilayer film as described in claim 1 or 2, wherein, The concentration of the crosslinking point of the polyurethane resin U2 is 0.05 mmol / g to 0.25 mmol / g, and the concentration of the urethane group of the polyurethane resin U2 is 1.0 mmol / g to 2.0 mmol / g. In the presence of urea groups, the concentration of the urethane group is the total concentration of the urethane group and the urea group.

5. The multilayer film as described in claim 1 or 2, which is used as a surface protective film for optical components.

Images