Resin composition, substrate for flexible device, flexible device, and sheet

Abstract

The resin composition includes a urethane (meth) acrylate, a monofunctional (meth) acrylate, and a photo-radical polymerization initiator. The urethane (meth) acrylate is a reaction product of a polyol component containing a predetermined polypropylene glycol, a polyisocyanate component containing at least one of an alicyclic polyisocyanate and an aliphatic polyisocyanate, and a hydroxyl group-containing (meth) acrylate. In a dynamic viscoelasticity measurement of a cured product of the resin composition, two or more specific peaks of the loss factor tan [delta] exist.

Description

Technical Field

[0001] This invention relates to resin compositions, substrates for flexible devices, flexible devices and sheets, and more specifically, to resin compositions, substrates for flexible devices comprising cured resin compositions, flexible devices having the substrates for flexible devices and sheets. Background Technology

[0002] In the past, flexible substrates have been used in the manufacture of devices that require flexibility (such as wearable devices, flexible sensors, flexible solar cells, flexible displays, etc.).

[0003] A flexible substrate is formed from the cured resin composition. As such a resin composition, an active energy radiation-curable composition comprising a monofunctional (meth)acrylate, a (meth)acrylate having urethane bonds, and a photoradical polymerization initiator has been proposed (see, for example, Patent Document 1). In Patent Document 1, a (meth)acrylate having urethane bonds is manufactured using polypropylene glycol (number average molecular weight 1000), dicyclohexylmethane-4,4'-diisocyanate, and 2-hydroxyethyl acrylate (see Manufacturing Example 1 of Patent Document 1).

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2019-172785 Summary of the Invention

[0005] The problem that the invention aims to solve On the other hand, flexible substrates require flexibility and elongation properties depending on their application and purpose.

[0006] In addition, flexible substrates require strength to resist deformation.

[0007] The present invention provides a resin composition with excellent flexibility, elongation and strength, a substrate for flexible devices comprising a cured product of the resin composition, a flexible device having the substrate for flexible devices, and a sheet.

[0008] Methods for solving problems The present invention [1] is a resin composition comprising urethane (meth)acrylate, monofunctional (meth)acrylate and photoradical polymerization initiator, wherein the urethane (meth)acrylate is a reaction product of polyol component, polyisocyanate component and hydroxyl-containing (meth)acrylate, wherein the polyol component comprises polypropylene glycol, wherein the number average molecular weight of the polypropylene glycol is 2000 or more, wherein the polyisocyanate component comprises at least one of alicyclic polyisocyanate and aliphatic polyisocyanate, wherein in the dynamic viscoelasticity determination of the cured resin composition, there are two or more peaks of loss factor tanδ, wherein the peaks include a first peak with a peak position below -20°C and a second peak with a peak position above 60°C.

[0009] The present invention [2] comprises the resin composition described in [1] above, wherein the number average molecular weight of the aforementioned polypropylene glycol is 3000 or more.

[0010] The present invention [3] comprises the resin composition described in [1] or [2] above, wherein the aforementioned monofunctional (meth)acrylate has an alicyclic structure.

[0011] The present invention [4] comprises the resin composition described in any one of [1] to [3] above, wherein the content of the aforementioned monofunctional (meth)acrylate is 60 to 320 parts by weight relative to 100 parts by weight of urethane (meth)acrylate.

[0012] The present invention [5] comprises the resin composition described in any one of [1] to [4] above, wherein the glass transition temperature of the aforementioned monofunctional (meth)acrylate homopolymer is 70°C or higher and 300°C or lower.

[0013] The present invention [6] comprises any of the resin compositions described in any one of [1] to [5] above, wherein the resin compositions further comprise difunctional (meth)acrylates.

[0014] The present invention [7] comprises the resin composition described above [6], wherein the content of the difunctional (meth)acrylate is 3 to 30 parts by mass relative to 100 parts by mass of the aforementioned urethane (meth)acrylate.

[0015] The present invention [8] comprises the resin composition described in any one of [1] to [7] above, wherein the difference between the peak position of the first peak and the peak position of the second peak (peak position of the second peak - peak position of the first peak) is 80°C or more and 300°C or less.

[0016] The present invention [9] comprises the resin composition described in any one of [1] to [8] above, wherein the double bond equivalent of the aforementioned urethane (meth) acrylate is 1000 g / eq. or more.

[0017] The present invention

[10] includes a substrate for flexible devices, wherein the aforementioned substrate for flexible devices comprises a cured product of the resin composition described in any one of [1] to [9] above.

[0018] The present invention

[11] includes a flexible device, wherein the aforementioned flexible device comprises the substrate for flexible devices described in

[10] above.

[0019] The present invention

[12] is a sheet containing a cured resin composition, wherein the resin composition contains urethane (meth)acrylate, monofunctional (meth)acrylate and a photoradical polymerization initiator, wherein the urethane (meth)acrylate is a reaction product of a polyol component, a polyisocyanate component and a hydroxyl-containing (meth)acrylate, wherein the polyol component contains polypropylene glycol, wherein the number average molecular weight of the polypropylene glycol is 2000 or more, wherein the polyisocyanate component contains at least one of alicyclic polyisocyanate and aliphatic polyisocyanate, wherein in the dynamic viscoelasticity determination of the cured resin composition, there are two or more peaks of the loss factor tanδ, wherein the peaks include a first peak with a peak position below -20°C and a second peak with a peak position above 60°C.

[0020] The present invention

[13] is a sheet containing a cured resin composition, wherein the resin composition contains urethane (meth)acrylate, monofunctional (meth)acrylate and a photoradical polymerization initiator, wherein the urethane (meth)acrylate is a reaction product of a polyol component, a polyisocyanate component and a hydroxyl-containing (meth)acrylate, wherein the polyol component contains polypropylene glycol, wherein the polypropylene glycol has a number average molecular weight of 2000 or more, wherein the polyisocyanate component contains at least one of alicyclic polyisocyanate and aliphatic polyisocyanate, wherein the sheet has a phase separation structure, wherein the layer mainly composed of the urethane (meth)acrylate and the layer mainly composed of monofunctional (meth)acrylate are different phases.

[0021] The present invention

[14] includes the sheet described in

[12] or

[13] above, wherein the number average molecular weight of the aforementioned polypropylene glycol is 3000 or more.

[0022] The present invention

[15] comprises the sheet material described in any one of

[12] to

[14] above, wherein the aforementioned monofunctional (meth)acrylate has an alicyclic structure.

[0023] The present invention

[16] comprises the sheet material described in any one of

[12] to

[15] above, wherein the content of the aforementioned monofunctional (meth)acrylate is 60 to 320 parts by weight relative to 100 parts by weight of urethane (meth)acrylate.

[0024] The present invention

[17] includes the sheet material described in any one of

[12] to

[16] above, wherein the glass transition temperature of the aforementioned monofunctional (meth)acrylate homopolymer is above 70°C and below 300°C.

[0025] The present invention

[18] includes the sheet material described in any one of

[12] to

[17] above, wherein the aforementioned sheet material further includes difunctional (meth)acrylate.

[0026] The present invention

[19] includes the sheet material described above

[18] , wherein the content of the difunctional (meth)acrylate is 3 to 30 parts by mass relative to 100 parts by mass of the aforementioned urethane (meth)acrylate.

[0027] The present invention

[20] includes the sheet material described in any one of

[12] to

[19] above, wherein the difference between the peak position of the first peak and the peak position of the second peak (peak position of the second peak - peak position of the first peak) is 80°C or more and 300°C or less.

[0028] The present invention

[21] comprises the sheet material described in any one of

[12] to

[20] above, wherein the double bond equivalent of the aforementioned urethane (meth) acrylate is 1000 g / eq. or more.

[0029] Invention Effects In the dynamic viscoelasticity determination of the cured resin composition of the present invention, the loss factor tanδ has two or more peaks, including a first peak with a peak position below -20°C and a second peak with a peak position above 60°C. In the cured resin composition, urethane (meth)acrylate and monofunctional (meth)acrylate undergo phase separation. Thus, the cured resin composition possesses both properties derived from urethane (meth)acrylate and properties derived from monofunctional (meth)acrylate.

[0030] The urethane (meth)acrylate is a reaction product of a polyol component comprising polypropylene glycol with a number average molecular weight of 2000 or more, a polyisocyanate component containing at least one of alicyclic and aliphatic polyisocyanates, and a hydroxyl-containing (meth)acrylate. According to this urethane (meth)acrylate, flexibility and elongation properties can be improved. Specifically, even at low temperatures (-20°C), flexibility and elongation properties are improved.

[0031] In addition, the resin composition contains a monofunctional (meth)acrylate. Based on such a monofunctional (meth)acrylate, the strength against deformation can be improved.

[0032] Furthermore, as described above, the cured resin composition possesses properties derived from both urethane (meth)acrylates and monofunctional (meth)acrylates. Therefore, it exhibits excellent flexibility, elongation, and resistance to deformation.

[0033] The substrate for flexible devices of the present invention comprises a cured product of the resin composition of the present invention. Therefore, it exhibits excellent flexibility, elongation properties, and strength.

[0034] The flexible device of the present invention possesses the flexible device of the present invention. Therefore, it has excellent flexibility, elongation properties and strength.

[0035] The sheet of the present invention exhibits a loss factor tanδ with two or more peaks, including a first peak with a apex below -20°C and a second peak with a apex above 60°C. In the cured product of such a resin composition, urethane (meth)acrylate and monofunctional (meth)acrylate undergo phase separation. Therefore, the sheet possesses properties derived from both urethane (meth)acrylate and monofunctional (meth)acrylate. Consequently, it exhibits excellent flexibility, elongation, and resistance to deformation.

[0036] Furthermore, the sheet of the present invention has a phase-separated structure in which the layer dominated by urethane (meth)acrylate and the layer dominated by monofunctional (meth)acrylate are different phases. Thus, the sheet possesses properties derived from both urethane (meth)acrylate and monofunctional (meth)acrylate. Therefore, it exhibits excellent flexibility, elongation, and resistance to deformation. Detailed Implementation

[0037] 1. Resin composition The resin composition comprises urethane (meth)acrylate, monofunctional (meth)acrylate, and a photoradical polymerization initiator.

[0038] <Carbamate (meth)acrylate> Carbamate (meth)acrylates are reaction products of polyols, polyisocyanates, and hydroxyl-containing (meth)acrylates. It should be noted that (meth)acrylates are methacrylates and / or acrylates.

[0039] (Polyol components) The polyol component includes polypropylene glycol. If the polyol component includes polypropylene glycol, the elongation properties are improved.

[0040] The number average molecular weight (Mn) of the polypropylene glycol is 2,000 or more, preferably 3,000 or more, more preferably 4,000 or more, even more preferably 5,000 or more, particularly preferably 8,000 or more, most preferably 9,000 or more, and even 10,000 or more, and for example, 50,000 or less, preferably 3,000 or less, and more preferably 15,000 or less.

[0041] If the number-average molecular weight (Mn) of polypropylene glycol is above the lower limit mentioned above, the elongation properties (especially the elongation properties at low temperatures) will be improved.

[0042] On the other hand, if the number-average molecular weight (Mn) of polypropylene glycol is lower than the aforementioned lower limit, the elongation properties will decrease.

[0043] It should be noted that the number-average molecular weight is the molecular weight converted from standard polystyrene based on gel permeation chromatography (GPC) (the same applies below).

[0044] The proportion of polypropylene glycol relative to the polyol component is, for example, 60% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, especially preferably 95% by mass or more, and most preferably 100% by mass.

[0045] The polyol component may include other polyols besides polypropylene glycol.

[0046] Other examples of polyols include low molecular weight polyols and high molecular weight polyols.

[0047] Low molecular weight polyols are compounds having two or more hydroxyl groups and a number average molecular weight of 40 or more but less than 400, preferably less than 300.

[0048] Examples of low molecular weight polyols include diols and triols.

[0049] Examples of diols include aliphatic diols, alicyclic diols, and aromatic diols.

[0050] Examples of aliphatic diols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and neopentanediol.

[0051] Examples of alicyclic diols include cyclohexanediol and hydrogenated bisphenol A.

[0052] Examples of aromatic diols include bisphenol A and 1,4-bis(2-hydroxyethoxy)benzene.

[0053] Examples of triols include glycerol, trimethylolpropane, and triisopropanolamine.

[0054] Low molecular weight polyols can be used alone or in combination of two or more.

[0055] The proportion of low molecular weight polyols relative to the polyol component is, for example, 20% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 1% by mass or less, and especially preferably 0% by mass. That is, it is particularly preferred that the polyol component does not contain low molecular weight polyols.

[0056] High molecular weight polyols are compounds having two or more hydroxyl groups, a number average molecular weight of 400 or more, preferably 500 or more, and less than 10,000.

[0057] Examples of high molecular weight polyols include, for example, polyether polyols (e.g., polyoxyalkylene polyols (excluding polypropylene glycol), polytetramethylene ether polyols), polycarbonate polyols, polyurethane polyols, epoxy polyols, vegetable oil polyols, polyolefin polyols, acrylic polyols, and vinyl monomer modified polyols.

[0058] High molecular weight polyols can be used alone or in combination of two or more.

[0059] The proportion of high molecular weight polyols relative to the polyol component is, for example, 20% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 1% by mass or less, and especially preferably 0% by mass. That is, it is particularly preferred that the polyol component does not contain high molecular weight polyols.

[0060] The polyol component is preferably formed from polypropylene glycol and does not contain other polyols.

[0061] (Polyisocyanate component) The polyisocyanate component includes at least one of alicyclic and aliphatic polyisocyanates. If the polyisocyanate component includes at least one of alicyclic and aliphatic polyisocyanates, it can improve flexibility.

[0062] Examples of alicyclic polyisocyanates include, for example, alicyclic diisocyanates. Examples of alicyclic diisocyanates include, for example, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), 4,4'-, 2,4'-, or 2,2'-methylenebis(cyclohexyl isocyanate), or mixtures thereof (H). 12MDI), 1,3- or 1,4-bis(isocyanate-methyl)cyclohexane or mixtures thereof (H6XDI), bis(isocyanate-methyl)norbornene (NBDI), 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, and methyl-2,6-cyclohexane diisocyanate.

[0063] As alicyclic polyisocyanates, IPDI and H are preferred examples. 12 MDI, 1,3- or 1,4-H6XDI. As alicyclic polyisocyanates, 1,3- or 1,4-H6XDI is more preferably chosen from the viewpoint of further improving flexibility at low temperatures.

[0064] From the viewpoint of further improving flexibility at low temperatures, 1,3-H6XDI is a preferred alicyclic polyisocyanate. Specifically, 1,4-H6XDI has a linear molecular structure, while 1,3-H6XDI has a curved molecular structure. Therefore, its flexibility at low temperatures can be further improved.

[0065] Alicyclic polyisocyanates include derivatives of the aforementioned alicyclic polyisocyanates.

[0066] Examples of derivatives of alicyclic polyisocyanates include polymers of the aforementioned alicyclic polyisocyanates, urethane derivatives, polyol derivatives, biuret derivatives, urea derivatives, oxadiazine trione derivatives, carbodiimide derivatives, urea dione derivatives, and urea ketone imine derivatives.

[0067] Alicyclic polyisocyanates can be used alone or in combination of two or more.

[0068] The proportion of alicyclic polyisocyanate relative to the polyisocyanate component is, for example, 60% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, especially preferably 95% by mass or more, and most preferably 100% by mass.

[0069] Examples of aliphatic polyisocyanates include, for example, aliphatic diisocyanates. Examples of aliphatic diisocyanates include, for example, 1,6-hexamethylene diisocyanate (1,6-HDI), 1,5-pentanediisocyanate (1,5-PDI), tetramethylene diisocyanate, trimethylene diisocyanate, 1,2-, 2,3- or 1,3-butanediisocyanate, and 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate.

[0070] Aliphatic polyisocyanates include derivatives of the aforementioned aliphatic polyisocyanates.

[0071] As a derivative of aliphatic polyisocyanates, it is the same as the derivatives mentioned in the category of alicyclic polyisocyanates.

[0072] From the viewpoint of further improving flexibility at low temperatures, 1,6-hexamethylene diisocyanate is preferred as an aliphatic polyisocyanate.

[0073] Aliphatic polyisocyanates can be used alone or in combination of two or more.

[0074] The proportion of aliphatic polyisocyanate relative to the polyisocyanate component is, for example, 60% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, especially preferably 95% by mass or more, and most preferably 100% by mass.

[0075] Polyisocyanate components may include other polyisocyanates besides alicyclic and aliphatic polyisocyanates.

[0076] Other examples of polyisocyanates include aromatic polyisocyanates and aromatic aliphatic polyisocyanates.

[0077] Examples of aromatic polyisocyanates include, for example, aromatic diisocyanates. Examples of aromatic diisocyanates include, for example, 4,4'-, 2,4'- or 2,2'-diphenylmethane diisocyanate or mixtures thereof (MDI), 2,4- or 2,6-toluene diisocyanate or mixtures thereof (TDI), o-toluene diisocyanate, 1,5-naphthalene diisocyanate (NDI), meta- or para-phenylene diisocyanate or mixtures thereof, 4,4'-diphenyl diisocyanate, and 4,4'-diphenyl ether diisocyanate.

[0078] Examples of aromatic aliphatic polyisocyanates include, for example, aromatic aliphatic diisocyanates. Examples of aromatic aliphatic diisocyanates include phenylene diisocyanate (1,2-, 1,3- or 1,4-phenylene diisocyanate or mixtures thereof) (XDI), 1,3- or 1,4-tetramethylphenylene diisocyanate or mixtures thereof (TMXDI), and ω,ω'-diisocyanate-1,4-diethylbenzene.

[0079] Other polyisocyanates include derivatives of the aforementioned other polyisocyanates.

[0080] As a derivative among other polyisocyanates, it is the same as the derivatives mentioned among alicyclic polyisocyanates.

[0081] Other polyisocyanates can be used alone or in combination of two or more.

[0082] The proportion of other polyisocyanates relative to the polyisocyanate component is, for example, 20% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 1% by mass or less, and especially preferably 0% by mass. That is, it is particularly preferred that the polyisocyanate component does not contain other polyisocyanates and is formed from at least one of alicyclic polyisocyanates and aliphatic polyisocyanates. It is further preferred that the polyisocyanate component is formed from alicyclic polyisocyanates or aliphatic polyisocyanates. Most preferably, the polyisocyanate component is formed from alicyclic polyisocyanates.

[0083] (Hydroxy-containing (meth)acrylates) Examples of hydroxyl-containing (meth)acrylates include, for example, hydroxyl-containing mono(meth)acrylates, hydroxyl-containing di(meth)acrylates, and hydroxyl-containing tri(meth)acrylates.

[0084] Examples of hydroxyl-containing mono(meth)acrylates include, for example, hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, butanediol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, 2-(6-hydroxyhexanoyloxy)ethyl acrylate, glycerol mono(meth)acrylate, trimethylolpropane mono(meth)acrylate, and pentaerythritol mono(meth)acrylate.

[0085] Examples of hydroxyl-containing di(meth)acrylates include glycerol di(meth)acrylate, trimethylolpropane di(meth)acrylate, and pentaerythritol di(meth)acrylate.

[0086] Examples of hydroxyl-containing tri(meth)acrylates include, for instance, pentaerythritol tri(meth)acrylate.

[0087] As a hydroxyl-containing (meth)acrylate, a hydroxyl-containing mono(meth)acrylate is preferred. As a hydroxyl-containing (meth)acrylate, hydroxyethyl (meth)acrylate is more preferred. As a hydroxyl-containing (meth)acrylate, hydroxyethyl acrylate is even more preferred.

[0088] Hydroxyl-containing (meth)acrylates can be used alone or in combination with two or more.

[0089] (Method for manufacturing urethane (meth)acrylates) In the manufacturing method of urethane (meth)acrylate, firstly, a polyol component is reacted with a polyisocyanate component to prepare an isocyanate-terminated prepolymer.

[0090] As a method for reacting the polyisocyanate component with the polyol component, a known polymerization method (e.g., bulk polymerization and solution polymerization) can be selected, with bulk polymerization being preferred.

[0091] In bulk polymerization, for example, polyisocyanate and polyol components are reacted under a nitrogen atmosphere.

[0092] In this reaction, the equivalence ratio (isocyanate group / active hydrogen group) of the isocyanate group in the polyisocyanate component to the active hydrogen group (hydroxyl group) in the polyol component is greater than 1, for example, 1.2 or more, preferably 1.3 or more, for example, 10.0 or less, preferably 9 or less, more preferably 5 or less, and even more preferably 3 or less. Under such conditions, the terminal functional group of the reaction product is an isocyanate group. That is, an isocyanate-terminated prepolymer is obtained.

[0093] As reaction conditions, the reaction temperature is, for example, 20°C to 110°C, preferably 60°C to 90°C. The reaction time is 1 hour to 20 hours, preferably 2 hours to 10 hours.

[0094] In addition, a reaction catalyst (e.g., amine-based, tin-based, and lead-based) may be added as needed in the above reaction.

[0095] In addition, in the above reaction, for example, known methods such as distillation and extraction can be used to remove unreacted polyisocyanate components and / or unreacted polyol components.

[0096] Thus, an isocyanate-terminated prepolymer is obtained as a reaction product of polyisocyanate and polyol components.

[0097] Next, the isocyanate-terminated prepolymer is reacted with hydroxyl-containing (meth)acrylate.

[0098] In this reaction, the equivalence ratio (isocyanate group / active hydrogen group) of the isocyanate group in the isocyanate-terminated prepolymer to the active hydrogen group (hydroxyl group) in the hydroxyl-containing (meth)acrylate is, for example, 0.8 to 1.2, preferably 0.9 to 1.1, and more preferably 1.0.

[0099] As reaction conditions, the reaction temperature is, for example, 20°C to 110°C, preferably 60°C to 90°C. The reaction time is 1 hour to 20 hours, preferably 2 hours to 10 hours.

[0100] In addition, a reaction catalyst (e.g., amine-based, tin-based, and lead-based) may be added as needed in the above reaction.

[0101] Thus, urethane (meth)acrylates are obtained as the reaction product of isocyanate-terminated prepolymer and hydroxyl-containing (meth)acrylate.

[0102] The double bond equivalent of the urethane (meth)acrylate is, for example, 1000 g / eq. or more, preferably 2000 g / eq. or more, more preferably 3000 g / eq. or more, further preferably 4000 g / eq. or more, especially preferably 5000 g / eq. or more, and also, for example, 20000 g / eq. or less, preferably 15000 g / eq. or less, more preferably 10000 g / eq. or less, further preferably 7000 g / eq. or less, especially preferably 6000 g / eq. or less.

[0103] If the double bond equivalent of urethane (meth)acrylate is above the lower limit mentioned above, flexibility can be improved.

[0104] In addition, if the double bond equivalent of urethane (meth)acrylate is below the above-mentioned upper limit, the elongation at break can be improved.

[0105] The double bond equivalent of urethane (meth)acrylate can be adjusted by modifying the combination of polyisocyanate and polyol components (e.g., the number-average molecular weight of polypropylene glycol).

[0106] It should be noted that the double bond equivalent of urethane (meth)acrylate can be calculated based on the charge amount.

[0107] <Monofunctional (meth)acrylates> Monofunctional (meth)acrylates have one (meth)acryloyl group.

[0108] Examples of monofunctional (meth)acrylates include monofunctional (meth)acrylates containing a ring structure and monofunctional (meth)acrylates without a ring structure.

[0109] Examples of monofunctional (meth)acrylates containing a ring structure include, for example, monofunctional (meth)acrylates containing an alicyclic structure, monofunctional (meth)acrylates containing an aliphatic heterocycle, and monofunctional (meth)acrylates containing an aromatic ring structure.

[0110] Examples of monofunctional (meth)acrylates containing an alicyclic structure include cyclohexyl (meth)acrylate and isobornyl (meth)acrylate. Isobornyl (meth)acrylate is preferred as a monofunctional (meth)acrylate containing an alicyclic structure. Isobornyl (meth)acrylate is more preferred as a monofunctional (meth)acrylate containing an alicyclic structure.

[0111] Examples of monofunctional (meth)acrylates containing aliphatic heterocycles include (meth)acryloylmorpholine.

[0112] Examples of monofunctional (meth)acrylates containing an aromatic ring structure include phenyl (meth)acrylate and benzyl (meth)acrylate.

[0113] Examples of non-cyclic monofunctional (meth)acrylates include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, and dodecyl (meth)acrylate. Methyl (meth)acrylate is preferably a non-cyclic monofunctional (meth)acrylate. Methyl methacrylate is more preferably a non-cyclic monofunctional (meth)acrylate.

[0114] From the viewpoint of flexibility and elongation properties, monofunctional (meth)acrylates containing a ring structure are preferred as monofunctional (meth)acrylates. From the viewpoint of flexibility and elongation properties, monofunctional (meth)acrylates containing an alicyclic structure are more preferred as monofunctional (meth)acrylates. That is, monofunctional (meth)acrylates having an alicyclic structure are more preferred.

[0115] Furthermore, from the viewpoint of flexibility and elongation properties, monofunctional (meth)acrylates are preferably monofunctional (meth)acrylates that do not contain aliphatic heterocycles.

[0116] The glass transition temperature of the homopolymer of monofunctional (meth)acrylate is, for example, 70°C or higher. From the viewpoint of strength against deformation, the glass transition temperature of the homopolymer of monofunctional (meth)acrylate is preferably 70°C or higher and lower than 150°C; on the other hand, from the viewpoint of recovery rate, it is 150°C or higher and lower than 300°C.

[0117] In addition, from the viewpoint of balancing the strength to resist deformation and the recovery rate, the glass transition temperature of the homopolymer of monofunctional (meth)acrylate is preferably 80~300℃, more preferably 90℃~260℃, and even more preferably 150℃~220℃.

[0118] In detail, the glass transition temperature of the homopolymer of monofunctional (meth)acrylate is, for example, 70°C or higher, preferably 80°C or higher, more preferably 90°C or higher, even more preferably 150°C or higher, and for example, 300°C or lower, preferably 260°C or lower, more preferably 220°C or lower.

[0119] If the glass transition temperature of the homopolymer of monofunctional (meth)acrylate is above the lower limit mentioned above, the strength against deformation can be improved.

[0120] The proportion of monofunctional (meth)acrylate is, for example, 60 to 320 parts by weight relative to 100 parts by weight of urethane (meth)acrylate.

[0121] In detail, when the glass transition temperature of the homopolymer of monofunctional (meth)acrylate is 70°C or higher and lower than 150°C, the content of monofunctional (meth)acrylate relative to 100 parts by weight of urethane (meth)acrylate is, for example, 60 parts by weight to 320 parts by weight, preferably 125 parts by weight to 270 parts by weight, more preferably 130 parts by weight to 220 parts by weight, and even more preferably 140 parts by weight to 200 parts by weight.

[0122] More specifically, when the glass transition temperature of the homopolymer of monofunctional (meth)acrylate is 70°C or higher and lower than 150°C, the content of monofunctional (meth)acrylate relative to 100 parts by weight of urethane (meth)acrylate is, for example, 60 parts by weight or higher, preferably 125 parts by weight or higher, more preferably 130 parts by weight or higher, even more preferably 140 parts by weight or higher, and for example, 320 parts by weight or less, preferably 270 parts by weight or less, more preferably 220 parts by weight or less, even more preferably 200 parts by weight or less.

[0123] On the other hand, when the glass transition temperature of the homopolymer of monofunctional (meth)acrylate is 150°C to 300°C or less, for example, it is 60 parts by mass to 320 parts by mass, preferably 62 parts by mass to 250 parts by mass, more preferably 65 parts by mass to 200 parts by mass, and even more preferably 70 parts by mass to 150 parts by mass.

[0124] Specifically, when the glass transition temperature of the homopolymer of monofunctional (meth)acrylate is 150°C or more and 300°C or less, for example, it is 60 parts by mass or more, preferably 62 parts by mass or more, more preferably 65 parts by mass or more, even more preferably 70 parts by mass or more, and for example, it is 320 parts by mass or less, preferably 250 parts by mass or less, more preferably 200 parts by mass or less, even more preferably 150 parts by mass or less.

[0125] If the content of monofunctional (meth)acrylate is above the lower limit mentioned above, the elongation properties can be improved.

[0126] In addition, if the content of monofunctional (meth)acrylates is below the above-mentioned upper limit, the recovery rate can be improved.

[0127] Monofunctional (meth)acrylates can be used alone or in combination with two or more types.

[0128] <Photoradical polymerization initiator> Examples of photoradical polymerization initiators include alkyl phenyl ketone compounds, acylphosphine oxide compounds, titanoceramic compounds, oxime ester compounds, benzoin compounds, acetophenone compounds, benzophenone compounds, thioxanone compounds, α-acyl oxime ester compounds, benzoylcarbamate compounds, benzoinyl compounds, azo compounds, diphenyl sulfide compounds, organic pigment compounds, iron-phthalocyanine compounds, benzoinyl ether compounds, and anthraquinone compounds. Acetophenone compounds are preferred as photoradical polymerization initiators.

[0129] It should be noted that commercially available products can be used as photopolymerization initiators. Examples of commercially available products include Omnirad 127 (acetophenone compound), Omnirad 184, Omnirad 1173, Omnirad 500, Omnirad 819, and Omnirad TPO (all manufactured by IGM Resins B.V.).

[0130] Photoradical polymerization initiators can be used alone or in combination of two or more.

[0131] The proportion of the photoradical polymerization initiator is, for example, 0.1 to 5 parts by mass, preferably 1 to 3 parts by mass, relative to the total amount of 100 parts by mass of urethane (meth)acrylate, monofunctional (meth)acrylate, and difunctional (meth)acrylate (described below) as required.

[0132] <Difunctional (meth)acrylates> The resin composition may also contain difunctional (meth)acrylates. The presence of difunctional (meth)acrylates in the resin composition enhances its resilience.

[0133] Difunctional (meth)acrylates have two (meth)acryloyl groups.

[0134] Examples of difunctional (meth)acrylates include, for example, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, propylene glycol dimethacrylate, tripropylene glycol dimethacrylate, butanediol dimethacrylate, neopentyl glycol dimethacrylate, hexanediol dimethacrylate, trimethylolethane dimethacrylate, trimethylolpropane dimethacrylate, glycerol dimethacrylate, pentaerythritol dimethacrylate, dipentaerythritol dimethacrylate, and dimethyloltricyclodecane dimethacrylate.

[0135] As a difunctional (meth)acrylate, dimethyloltricyclodecane di(meth)acrylate is preferably selected. As a difunctional (meth)acrylate, dimethyloltricyclodecane dimethacrylate is more preferably selected.

[0136] Difunctional (meth)acrylates can be used alone or in combination with two or more.

[0137] The proportion of difunctional (meth)acrylate relative to 100 parts by weight of urethane (meth)acrylate is, for example, 0.5 parts by weight to 40 parts by weight, preferably 3 parts by weight to 30 parts by weight, more preferably 5 parts by weight to 28 parts by weight, further preferably 10 parts by weight to 25 parts by weight, especially preferably 16 parts by weight to 24 parts by weight, and most preferably 21 parts by weight to 23 parts by weight.

[0138] Specifically, relative to 100 parts by weight of urethane (meth)acrylate, the content of difunctional (meth)acrylate is, for example, 0.5 parts by weight or more, preferably 3 parts by weight or more, more preferably 5 parts by weight or more, further preferably 10 parts by weight or more, especially preferably 16 parts by weight or more, most preferably 21 parts by weight or more, and for example, 40 parts by weight or less, preferably 30 parts by weight or less, more preferably 28 parts by weight or less, further preferably 25 parts by weight or less, especially preferably 24 parts by weight or less, and most preferably 23 parts by weight or less.

[0139] If the content of difunctional (meth)acrylate is above the lower limit mentioned above, the recovery ability can be improved.

[0140] In addition, if the content of difunctional (meth)acrylates is below the above-mentioned upper limit, flexibility can be improved.

[0141] <Additives> The resin composition may contain additives as needed.

[0142] Examples of additives include, for example, antioxidants, sensitizers, fillers, antistatic agents, coupling agents, stabilizers, and surfactants.

[0143] <Method for manufacturing resin composition> The resin composition can be manufactured by mixing urethane (meth)acrylate, monofunctional (meth)acrylate, photoradical polymerization initiator, difunctional (meth)acrylate as needed, and additives as needed, and stirring as needed.

[0144] Stirring can be carried out using known stirring devices, such as propeller mixers, planetary mixers, mixing agitators, kneaders, emulsifiers, three-roll mills, bead mills, and ultrasonic homogenizers. Alternatively, stirring can be performed while heating or cooling is in place, as needed.

[0145] Thus, a resin composition is manufactured.

[0146] In addition, the resin composition can be diluted using known solvents.

[0147] <Cure of the resin composition> Cured products of resin compositions can be obtained by curing the resin composition.

[0148] To cure the resin composition, it is irradiated with active energy rays (preferably ultraviolet light). The irradiation condition for the active energy rays is, for example, an illuminance of 50 mW / cm². 2 ~5000mw / cm 2 The irradiation time is, for example, 0.5 seconds to 5000 seconds.

[0149] Thus, a cured product of the resin composition is manufactured.

[0150] In addition, in the dynamic viscoelasticity determination of the cured resin composition, there are more than two peaks of loss factor tanδ.

[0151] Specifically, the peak includes the first peak and the second peak.

[0152] The peak of the first peak is located below -20°C, preferably below -30°C, more preferably below -40°C, and for example above -70°C, preferably above -60°C.

[0153] The peak position of the second peak is above 60°C, preferably above 70°C, more preferably above 80°C, even more preferably above 100°C, especially preferably above 130°C, and for example below 220°C, more preferably below 200°C, even more preferably below 190°C, especially preferably below 180°C.

[0154] Furthermore, the difference between the peak position of the first peak and the peak position of the second peak (peak position of the second peak - peak position of the first peak) is, for example, 80°C to 300°C, preferably 100°C to 250°C, more preferably 130°C to 250°C, even more preferably 140°C to 250°C, and especially preferably 180°C to 250°C.

[0155] In detail, from the viewpoint of low temperature characteristics and recovery rate, the difference between the peak position of the first peak and the peak position of the second peak (peak position of the second peak - peak position of the first peak) is, for example, 80°C or more, preferably 100°C or more, more preferably 130°C or more, even more preferably 140°C or more, and especially preferably 180°C or more. In addition, from the viewpoint of low temperature characteristics and recovery rate, it is, for example, 300°C or less, preferably 250°C or less.

[0156] If the cured resin composition has the above-mentioned peaks (peak 1 and peak 2), then in the cured resin composition, urethane (meth)acrylate and monofunctional (meth)acrylate undergo phase separation. Specifically, peak 1 is the peak originating from urethane (meth)acrylate, and peak 2 is the peak originating from monofunctional (meth)acrylate.

[0157] In addition, the cured resin composition has a phase separation structure in which the layer mainly composed of urethane (meth)acrylate and the layer mainly composed of monofunctional (meth)acrylate are different phases.

[0158] Examples of phase-separated structures include, for instance, sea-island structures and co-continuous structures. In the case of sea-island structures, in higher-order structures of incompatible polymer blends, one polymer forms the matrix, while the other forms the dispersed phase. Co-continuous structures are those in which a phase transition occurs in the sea-island structure under conditions where the composition of the polymers constituting the blend is approximately proportional to their respective melt viscosity ratios. These structures are higher-order structures that appear near conditions where the composition and viscosity ratio change, thus reversing the sea-island relationship; they are structures where two polymers form a continuous phase with each other.

[0159] Furthermore, detailed information is provided in the examples described later, and the phase separation structure in the cured resin composition can be confirmed by atomic force microscopy.

[0160] <Substrates for Flexible Devices and Flexible Devices> A substrate for flexible devices is a substrate used in the manufacture of flexible devices. Examples of flexible devices include, for instance, foldable displays.

[0161] The substrate for flexible devices comprises a cured resin composition.

[0162] Such a substrate for flexible devices can be obtained as follows: the above-described resin composition is cured and molded into a sheet shape using the above method.

[0163] Furthermore, the flexible device is obtained using the aforementioned flexible device substrate. Specifically, the flexible device includes a flexible device substrate and electronic components disposed on the flexible device substrate.

[0164] <Effects> The cured resin composition exhibits the aforementioned peaks (peak 1 and peak 2), thus, in the cured resin composition, urethane (meth)acrylate and monofunctional (meth)acrylate undergo phase separation. Therefore, the cured resin composition possesses properties derived from both urethane (meth)acrylate and monofunctional (meth)acrylate.

[0165] The urethane (meth)acrylate is a reaction product of a polyol component comprising polypropylene glycol with a number average molecular weight of 2000 or more, a polyisocyanate component containing at least one of alicyclic and aliphatic polyisocyanates, and a hydroxyl-containing (meth)acrylate. According to this urethane (meth)acrylate, flexibility and elongation properties can be improved. Specifically, even at low temperatures (-20°C), flexibility and elongation properties are improved.

[0166] In addition, the resin composition contains a homopolymer of a monofunctional (meth)acrylate. Based on such a monofunctional (meth)acrylate, the strength against deformation can be improved.

[0167] Furthermore, as mentioned above, the cured resin composition possesses properties derived from both urethane (meth)acrylates and monofunctional (meth)acrylates. Therefore, it exhibits excellent flexibility, elongation, and resistance to deformation.

[0168] The substrate for flexible devices comprises a cured product of the above-mentioned resin composition. Therefore, it exhibits excellent flexibility, elongation properties, and resistance to deformation.

[0169] The flexible device possesses the aforementioned flexible characteristics. Therefore, it exhibits excellent flexibility, elongation properties, and resistance to deformation.

[0170] Example Next, the present invention will be described based on embodiments and comparative examples, but the present invention is not limited to the embodiments described below. It should be noted that unless otherwise specified, "parts" and "%" are based on mass. In addition, the specific values ​​of proportions (including proportions), physical property values, parameters, etc. used in the following description can be replaced with the corresponding upper limit values ​​(values ​​defined in the form of "below" or "less than") or lower limit values ​​(values ​​defined in the form of "above" or "greater than") of the proportions (including proportions), physical property values, parameters, etc., described in the "Specific Embodiments" above.

[0171] <Ingredient Details> The trade names and abbreviations of the ingredients used in each embodiment and comparative example are described in detail.

[0172] PPG: Polypropylene Glycol PTMEG: Polytetramethylene ether diol 1,3-H6XDI: 1,3-bis(isocyanate-methyl)cyclohexane IPDI: Isophorone diisocyanate H 12 MDI: Methylene bis(cyclohexyl isocyanate) XDI: Diphenylethylene diisocyanate HDI: 1,6-hexamethylene diisocyanate HEA: Hydroxyethyl acrylate IBX: Isoborneol Methacrylate MMA: Methyl methacrylate ACMO: Acryloylmorpholine IBXA: Isoborneol Acrylate EBECRYL114: Phenoxyethyl acrylate, manufactured by DAICEL-ALLNEX LTD DCPA: Dimethyloltricyclodecane diacrylate DCP: Dimethyloltricyclodecane dimethacrylate Omnirad184: Photopolymerization initiator, manufactured by IGM Resins B.V. Irganox245: Antioxidant Manufacturing Examples 1 to 12 <Manufacturing of Carbamate (Meth)acrylates> Under a nitrogen atmosphere, based on the formulations described in Table 1, the polyol and polyisocyanate components were combined in a glass separable flask. Then, after heating to 80°C, a carbamate catalyst (stannous octoate (tin ethylhexanoate (II))) was added to the mixture of polyol and polyisocyanate components at a ratio of 10 ppm. The mixture was then allowed to react for 4 hours. This yielded a reaction solution containing isocyanate-terminated prepolymers.

[0173] Next, the reaction solution containing the isocyanate-terminated prepolymer was placed in a Smith thin-film distillation apparatus to separate the isocyanate-terminated prepolymer from the unreacted polyisocyanate component under the following conditions. This process purified the isocyanate-terminated prepolymer.

[0174] {condition} Temperature requirements: 160~170℃ Pressure conditions: 70~100Pa Supply flow rate: 3.5~4 g / min Next, under atmospheric conditions (dry air), based on the formulations described in Table 1, the isocyanate-terminated prepolymer and the hydroxyl-containing (meth)acrylate were formulated into a separable flask such that the equivalent ratio (isocyanate group / active hydrogen group) of the isocyanate-terminated prepolymer to the active hydrogen group (hydroxyl group) in the hydroxyl-containing (meth)acrylate was 1.0.

[0175] Next, the temperature is raised to 70°C, and stannous octoate (tin ethylhexanoate (II)) is added as a urethane catalyst at a ratio of 200 ppm relative to the isocyanate-terminated prepolymer, and the reaction is carried out for 4 hours until the isocyanate concentration is below 0.01%. This produces urethane (meth)acrylate.

[0176] <Preparation of Resin Compositions> Examples 1 to 21 and Comparative Examples 1 to 6 The components are mixed according to Tables 2-5. Thus, a resin composition is manufactured.

[0177] <Preparation of cured resin compositions> The resin compositions of each embodiment and comparative example were coated onto a PET film using a doctor blade to obtain a coating film with a thickness of 100 μm. The coating film was then irradiated with active energy rays (illuminance 200 mw / cm²). 2 (Irradiation time 60 seconds). Thus, a cured resin composition is produced.

[0178] <Evaluation> (Energy storage elastic modulus) For the cured resin compositions of each embodiment and comparative example, the storage modulus (-20°C) and storage modulus (25°C) were measured. Specifically, the dynamic viscoelasticity of the cured resin compositions was measured under the following conditions according to JIS K7244 (1998): A type A dumbbell-shaped test piece was used as the test sample. The tensile mode was used as the test mode. The measurement frequency was set to 10 Hz. The measurement temperature range was set to -100 to 250°C. The heating rate was set to 5°C / min, and the storage modulus at -20°C and 25°C was measured. The results are shown in Tables 2 to 5.

[0179] (Tension test) Tensile tests were performed on the cured resin compositions of each embodiment and comparative example. Specifically, a 201X universal testing machine (manufactured by INTESCO Co., Ltd.) was used, and tensile tests were performed at a chuck distance of 30 mm and a speed of 300 mm / min to determine the strength at break and elongation. The results are shown in Tables 2 to 5.

[0180] (Recovery rate) For the cured resin compositions of each embodiment and comparative example, the recovery rate was determined. Specifically, using a 201X universal testing machine (manufactured by INTESCO Co., Ltd.), with a chuck distance of 30 mm and a speed of 1 Hz, the cured resin was stretched by 5% and held for 5 minutes, then recovered to 0%, allowed to stand for 10 minutes, and then the length was measured using vernier calipers and the elongation was calculated. The results are shown in Tables 2 to 5.

[0181] (Atomic force microscopy) Atomic force microscopy (AFM) measurements were performed on the cured resin compositions of Examples 16 and 17. Specifically, hardness was measured by phase difference detection using AFM within a 2 μm × 1 μm measurement range near the center of the cross-section of the cured resin composition in the thickness direction, with a resolution of 19.5 nm on the 2 μm side and 7.8 nm on the 1 μm side. The results showed that the cured resin compositions of Examples 16 and 17 exhibited a phase-separated structure.

[0182] [Table 1] [Table 2] [Table 3] [Table 4] [Table 5] It should be noted that the above-described invention is provided as an example embodiment of the present invention, but it is merely an example and not intended to be limiting. Modifications of the present invention that will be apparent to those skilled in the art are included in the appended claims.

[0183] Industrial availability The resin composition, substrate for flexible devices, flexible devices and sheets of the present invention are preferably used in the manufacture of flexible devices such as wearable devices, flexible sensors, flexible solar cells and flexible displays.

Claims

1. A resin composition comprising a urethane (meth)acrylate, a monofunctional (meth)acrylate, and a photoradical polymerization initiator. The urethane (meth)acrylate is a reaction product of polyol components, polyisocyanate components, and hydroxyl-containing (meth)acrylates. The polyol component includes polypropylene glycol. The number-average molecular weight of the polypropylene glycol is above 2000. The polyisocyanate component includes at least one of alicyclic and aliphatic polyisocyanates. In the dynamic viscoelasticity determination of the cured resin composition, the loss factor tanδ has two or more peaks. The peaks include a first peak with a peak temperature below -20°C and a second peak with a peak temperature above 60°C.

2. The resin composition according to claim 1, wherein, The number-average molecular weight of the polypropylene glycol is above 3000.

3. The resin composition of claim 1, wherein, The monofunctional (meth)acrylate has an alicyclic structure.

4. The resin composition of claim 1, wherein, The monofunctional (meth)acrylate contains 60 to 320 parts by weight relative to 100 parts by weight of urethane (meth)acrylate.

5. The resin composition of claim 1, wherein, The glass transition temperature of the homopolymer of the monofunctional (meth)acrylate is above 70°C and below 300°C.

6. The resin composition of claim 1, further comprising a difunctional (meth)acrylate.

7. The resin composition of claim 6, wherein, The difunctional (meth)acrylate contains 3 to 30 parts by weight relative to 100 parts by weight of the urethane (meth)acrylate.

8. The resin composition of claim 1, wherein, The difference between the peak position of the first peak and the peak position of the second peak (peak position of the second peak - peak position of the first peak) is above 80°C and below 300°C.

9. The resin composition of claim 1, wherein, The double bond equivalent of the aforementioned urethane (meth)acrylate is above 1000 g / eq.

10. A substrate for flexible devices comprising a cured product of the resin composition according to any one of claims 1 to 9.

11. A flexible device comprising the substrate for a flexible device as described in claim 10.

12. A sheet comprising a cured resin composition comprising a urethane (meth)acrylate, a monofunctional (meth)acrylate, and a photoradical polymerization initiator. The urethane (meth)acrylate is a reaction product of polyol components, polyisocyanate components, and hydroxyl-containing (meth)acrylates. The polyol component includes polypropylene glycol. The number-average molecular weight of the polypropylene glycol is above 2000. The polyisocyanate component includes at least one of alicyclic and aliphatic polyisocyanates. In the dynamic viscoelasticity determination of the cured resin composition, the loss factor tanδ has two or more peaks. The peaks include a first peak with a peak temperature below -20°C and a second peak with a peak temperature above 60°C.

13. A sheet comprising a cured resin composition comprising a urethane (meth)acrylate, a monofunctional (meth)acrylate, and a photoradical polymerization initiator. The urethane (meth)acrylate is a reaction product of polyol components, polyisocyanate components, and hydroxyl-containing (meth)acrylates. The polyol component includes polypropylene glycol. The number-average molecular weight of the polypropylene glycol is above 2000. The polyisocyanate component includes at least one of alicyclic and aliphatic polyisocyanates. The sheet has a phase separation structure, in which the layer mainly composed of the aforementioned urethane (meth)acrylate and the layer mainly composed of monofunctional (meth)acrylate are different phases.

Images