Silicone polyurethane, stretchable film, and method for forming the same

Abstract

To provide a silicone polyurethane which becomes a material of an elastic film having excellent elasticity and strength, and excellent in water repellency of a film surface, the elastic film, and a formation method of the elastic film.SOLUTION: The silicone polyurethane has a maleimide group at least on a terminal thereof.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to silicone polyurethane, a stretchable film, and a method for forming the same.

Background Art

[0002] In recent years, with the spread of IoT (Internet of Things), the development of wearable devices has been progressing. Examples include watches and glasses that can be connected to the Internet. Also, in the medical and sports fields, wearable devices that can constantly monitor the body's condition are required and are a growing field in the future.

[0003] As a wearable device, a form that is attached to the body to constantly monitor the body's condition is shown. Such a wearable device usually consists of a bioelectrode for detecting an electrical signal from the body, a wiring for sending the electrical signal to a sensor, a semiconductor chip serving as a sensor, and a battery. Also, usually, an adhesive pad for adhering to the skin is required. The structure of the bioelectrode and the wiring and adhesive pad around it are described in detail in Patent Document 1. The wearable device described in Patent Document 1 has a silicone-based adhesive film disposed around the bioelectrode, and the space between the bioelectrode and the sensor device is connected by a bellows-shaped stretchable silver wiring covered with a stretchable urethane film.

[0004] The urethane film has high stretchability and strength and excellent mechanical properties as a coating film for stretchable wiring. However, since the urethane film has hydrolyzability, it has a drawback that its stretchability and strength decrease due to hydrolysis. On the other hand, although the silicone film has no hydrolyzability, it has a drawback of low strength.

[0005] Therefore, silicone urethane polymers having both urethane bonds and siloxane bonds in the polymer main chain have been studied. The cured product of this polymer has higher strength than silicone alone and lower hydrolyzability than polyurethane alone. However, the cured product of this polymer cannot reach the strength of polyurethane alone or the water repellency of silicone alone, and only intermediate strength and water repellency between silicone and polyurethane can be obtained.

[0006] Silicone urethanes having silicone in the side chain and urethane in the main chain have been proposed (Patent Documents 2 and 3). In this case, since the main chain is a high-elasticity and high-strength urethane and a highly water-repellent silicone chain is attached to the side chain, it has higher strength than silicone urethane having a silicone chain in the main chain. However, since the silicone chain in the side chain is linear, the influence of the low strength of silicone appears and the strength decreases. Therefore, silicone urethanes having a urethane main chain and branched short-chain silicone attached to the side chain have been proposed (Patent Document 4). In this material, there is no decrease in strength, and the characteristic of high water repellency due to silicone can be obtained. Furthermore, in silicone urethanes having a urethane main chain and two branched short-chain silicones attached to the side chain (Patent Documents 5 and 6), the water repellency can be further improved while maintaining high strength. However, further improvement in strength is required.

[0007] It is known that bismaleimide groups are coupled and crosslinked by light (Non-Patent Document 1). Due to the rigid ring structure of the maleimide group, it has high-strength and high heat-resistant properties. A high heat-resistant resin using a radical crosslinking reaction between maleimide and methacryl has been proposed (Patent Document 7).

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

[0009] [Non-Patent Document 1] Toagosei Annual Report TREND 2002, No. 5, p11 [Summary of the Invention] [Problems to be Solved by the Invention]

[0010] Against such a background, it is desired to develop a silicone polyurethane, a stretchable film, and a method for forming a stretchable film that serve as materials for a stretchable film having high stretchability, excellent strength equal to or higher than that of polyurethane, and excellent water repellency equal to or higher than that of silicone.

[0011] Therefore, in view of the above circumstances, an object of the present invention is to provide a silicone polyurethane, a stretchable film, and a method for forming a stretchable film that serve as materials for a stretchable film having excellent stretchability and strength and excellent water repellency on the film surface. [Means for Solving the Problems]

[0012] In order to solve the above problems, the present invention provides a silicone polyurethane having a maleimide group at least at its terminal.

[0013] Such a silicone polyurethane becomes a silicone polyurethane that serves as a material for a stretchable film having excellent stretchability and strength and excellent water repellency on the film surface.

[0014] In the present invention, it is preferable that the silicone polyurethane having a maleimide group at the terminal has silicone in the side chain.

[0015] Such a silicone polyurethane can be made into a higher-strength silicone polyurethane.

[0016] In the present invention, it is preferable that the silicone polyurethane having a maleimide group at the terminal has a structure represented by the following general formula (1).

Chemical formula

[0017] Such a silicone polyurethane can further improve the effects of the present invention.

[0018] In addition, in the present invention, it is preferable that the silicone polyurethane having a maleimide group at the terminal has a soft segment selected from polyethers, polyesters, and polycarbonates.

[0019] When using polyether as the soft segment, the silicone polyurethane will have higher stretchability, higher strength, and higher water repellency. When using polycarbonate as the soft segment, the high water repellency of the silicone polyurethane resin remains unchanged, the stretchability decreases compared to the case of polyether, but the strength improves. Also, in the case of a polyester soft segment, it has high water repellency, and the mechanical properties are intermediate between those of polyether and polycarbonate.

[0020] In addition, in the present invention, it is preferable that the soft segment selected from the polyethers, polyesters, and polycarbonates is represented by the following general formula (2).

Chemical formula

[0021] Such a silicone polyurethane can further improve the effects of the present invention.

[0022] The present invention also provides a stretchable film formed by curing a stretchable film material containing the silicone polyurethane.

[0023] Such a stretchable film has high stretchability and superior strength to polyurethane alone, and is a stretchable film with superior water repellency to silicone alone.

[0024] In the present invention, the stretchable film preferably has a stretch percentage in the range of 20 to 1000% in a tensile test specified in JIS K 6251.

[0025] The stretch film of the present invention preferably has such properties.

[0026] In addition, the present invention also provides a method for manufacturing a film, the method comprising the steps of: applying a stretchable film material containing the silicone polyurethane; and A step of hardening the stretchable film material by heating and / or light irradiation. The present invention provides a method for forming a stretchable film, comprising:

[0027] Such a method for forming a stretchable film makes it possible to easily and efficiently form a stretchable film that is highly stretchable, has strength superior to that of polyurethane, and has water repellency superior to that of silicone. [Effects of the Invention]

[0028] As described above, in the case of a stretchable film formed by curing using a silicone polyurethane having a maleimide group at the end of the present invention, it has high stretchability and strength higher than that of polyurethane alone, and is a highly water-repellent stretchable film higher than that of silicone alone. Furthermore, it becomes a self-supporting stretchable film in which the films do not stick to each other. Therefore, if it is a stretchable film formed by curing using a silicone polyurethane having a maleimide group at the end of the present invention, in a wearable device, not only the wiring part connecting the bioelectrode and the sensor and the film covering the sensor, but also the stretchable film can be used particularly preferably as a stretchable film on which all the bioelectrodes and sensors can be placed. In addition, if it is a method for forming a stretchable film formed by curing using a silicone polyurethane having a maleimide group at the end of the present invention, a stretchable film as described above can be easily formed.

Brief Description of the Drawings

[0029]

Figure 1

Embodiments for Carrying Out the Invention

[0030] As described above, there has been a demand for the development of a silicone polyurethane, a stretchable film, and a method for forming a stretchable film, which are materials for a stretchable film having stretchability, excellent strength, and excellent water repellency.

[0031] Polyurethane has sufficient elasticity and strength, but has the disadvantages of low water repellency and a decrease in strength and elasticity due to hydrolysis. Silicone has the disadvantage of high water repellency but low strength. In addition, the cured product of silicone polyurethane having both urethane bonds and siloxane bonds in the main chain has excellent water repellency but has the disadvantage of lower strength compared to urethane. A film based on polyurethane with short-chain branched silicone pendent on the side chain was excellent in elasticity and water repellency and had higher strength than conventional silicone urethane, but further higher strength characteristics were required. Against this background, there has been a demand for the development of a silicone polyurethane, a stretchable film, and a method for forming a stretchable film that are stretchable, have strength greater than that of polyurethane alone, and have excellent water repellency comparable to or greater than that of silicone alone.

[0032] Therefore, by producing a sheet obtained by curing a silicone polyurethane having a maleimide group introduced at its terminal, a stretchable film having stretchability, excellent strength, and water repellency is obtained, and it has been found that the stretchable film is particularly suitable as a stretchable substrate film for forming stretchable wiring in wearable devices and as a film for protecting devices, and the present invention has been completed.

[0033] That is, the present invention is a silicone polyurethane having a maleimide group at least at its terminal.

[0034] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0035] <Stretchable film> The stretchable film of the present invention is a stretchable film composed of a cured product of a stretchable film material containing a silicone polyurethane resin having a maleimide group introduced at least at its terminal.

[0036] <Silicone polyurethane having a maleimide group at its terminal> The silicone polyurethane (resin) having a maleimide group at the end of the present invention is not particularly limited. For example, it preferably has silicone in the side chain, and more preferably is a silicone pendant type polyurethane resin having a structure represented by the following general formula (1). [Chemical Formula] (In the formula, R 1 , R 2 , R 3 are the same or different linear, branched, or cyclic alkyl groups having 1 to 6 carbon atoms, phenyl groups, or 3,3,3-trifluoropropyl groups. R 4 are the same or different linear, branched, or cyclic alkyl groups having 1 to 6 carbon atoms, phenyl groups, 3,3,3-trifluoropropyl groups, or -(OSiR 1 R 2 ) s -OSiR 1 R 2 R 3 groups. s is an integer in the range of 0 to 100. R 5 is a hydrogen atom, or a linear or branched alkyl group having 1 to 4 carbon atoms, R 6 is a single bond, a methylene group, or an ethylene group, R 7 is a hydrogen atom or a methyl group. R 8 , R 9 are hydrogen atoms, linear, branched, or cyclic alkyl groups having 1 to 6 carbon atoms, alkenyl groups having 2 to 10 carbon atoms, alkynyl groups having 2 to 10 carbon atoms, or aryl groups having 6 to 10 carbon atoms, and R 8 and R 9 may combine to form a ring. X is a linear or branched alkylene group having 3 to 7 carbon atoms and may contain an ether group, Y is a linear, branched, or cyclic alkylene group having 1 to 40 carbon atoms and may have an ether bond, ester bond, amide bond, urethane bond, urea bond, or may have a phenylene group. q and r are integers in the range of 0 to 20. a1 and a2 are the ratios of the repeating units, and are in the range of 0 ≦ a1 ≦ 1.0, 0 ≦ a2 ≦ 1.0, and 0 < a1 + a2 ≦ 1.0. n is an integer of 1 to 4.)

[0037] Such a polyurethane pendant with silicone has high strength and high elasticity because all of its main chain is polyurethane. An appropriate amount, for example, a small amount of pendant silicone chains endows it with high water repellency, and it is possible to obtain the properties of high strength, high elasticity, and high water repellency. Therefore, it is preferable as the silicone polyurethane resin used in the present invention.

[0038] Furthermore, when the maleimide groups at the polymer terminals are bonded and crosslinked during curing, a film with higher strength than that of urethane alone is formed.

[0039] At this time, it is preferable that the silicone polyurethane having a maleimide group at the terminal has a soft segment selected from polyethers, polyesters, and polycarbonates, and it is more preferable that it has a soft segment selected from polyethers, polyesters, and polycarbonates represented by the following general formula (2).

Chemical formula

[0040] R 10 ~R 21 are the same or different linear, branched, or cyclic alkylene groups having 2 to 12 carbon atoms. Specifically, they are an ethylene group, an n-propylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, a cyclohexylene group, a cyclohexylene dimethyl group, an adamantylene group, an adamantylene dimethyl group, an isobutylene group, or a dimethylpentene group.

[0041] m is the same or different and is from 1 to 200.

[0042] In particular, it is preferable that the silicone polyurethane is the silicone pendant type polyurethane resin. That is, it is preferably a silicone polyurethane represented by the following general formula (3).

Chemical formula

[0043] A soft segment can be introduced into the silicone polyurethane used in the present invention. When a polyether is used as the soft segment, the silicone polyurethane resin becomes more stretchable, stronger, and more water-repellent. When a polycarbonate as described above is used as the soft segment, the high water-repellency of the silicone polyurethane resin remains unchanged, the stretchability decreases compared to the case of polyether, but the strength improves. In the case of a polyester soft segment, it has high water-repellency and mechanical properties are intermediate between those of polyether and polycarbonate. The structure of the soft segment is as shown in the general formulas (2) and (3).

[0044] Examples of the diol compound for forming the structure (repeating unit) represented by a1 in the above general formula (1) or (3) include compounds represented by the following general formula (a)-1’.

Chemical formula

[0045] R 1 、R 2 、R 3is a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, or a 3,3,3-trifluoropropyl group, which may be the same or different. Specifically, it is a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a cyclopentyl group, an n-hexyl group, a cyclohexyl group, a phenyl group, or a 3,3,3-trifluoropropyl group, which may be the same or different.

[0046] R 4 is a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, a 3,3,3-trifluoropropyl group, or -(OSiR 1 R 2 ) s -OSiR 1 R 2 R 3 group, where s is an integer in the range of 0 to 100. Specifically, it is a methyl group, an ethyl group, or a trimethylsiloxy group.

[0047] R 5 is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. Specifically, it is a methyl group, an ethyl group, an n-propyl group, or an n-butyl group.

[0048] R 6 is a single bond, a methylene group, or an ethylene group. Preferably, it is a methylene group or an ethylene group.

[0049] R 7 is a hydrogen atom or a methyl group. Preferably, it is a methyl group.

[0050] X is a linear or branched alkylene group having 3 to 7 carbon atoms, which may contain an ether group. Specifically, it is a propylene group, a butylene group, or a propyl ether ethyl group.

[0051] q and r are integers in the range of 0 to 20. Preferably, they are 1 to 4.

[0052] The diol compound pendant with a short-chain silicone represented by the general formula (a)-1’ can be obtained, for example, by reacting glycerin monoallyl ether with a short-chain siloxane compound having an SiH group in the presence of a platinum catalyst. Specifically, it can be exemplified as follows, but is not limited thereto.

[0053]

Chemical formula

[0054]

Chemical formula

[0055] Examples of the diol compound for forming the structure (repeating unit) represented by a2 in the above general formula (1) or (3) include compounds represented by the following general formula (a)-2’.

Chemical formula

[0056] The diol compound pendant with a short-chain silicone represented by the general formula (a)-2’ can be obtained, for example, by reacting a dihydroxydialkenyl compound with a short-chain siloxane compound having an SiH group in the presence of a platinum catalyst. Specifically, it can be exemplified as follows, but is not limited thereto.

[0057]

Chemical formula

[0058]

Chemical formula

[0059]

Chemical formula

[0060] [Chemical formula]

[0061] [Chemical formula]

[0062] [Chemical formula] (The repeating number in the formula indicates the average value.)

[0063] [Chemical formula]

[0064] To obtain the soft segment of the polyether of the repeating unit b1 in the general formula (2) or (3), a polyether compound having a diol at the end, exemplified below, can be used as a raw material.

[0065] [Chemical formula] Here, the repeating number in the parentheses is 1 to 200.

[0066] To obtain the soft segment of the polycarbonate of the repeating unit b2 in the general formula (2) or (3), a polycarbonate compound having a diol at the end, exemplified below, can be used as a raw material.

[0067] ... [Chemical formula] Here, the repeating number in the parentheses is 1 to 200.

[0068] To obtain the polyester soft segment of the repeating unit b3 in the general formula (2) or (3), a polyester compound with a terminal diol exemplified below can be used as a raw material.

[0069]

Chemical formula

[0070] To obtain the polyester soft segment of the repeating unit b4 in the general formula (2) or (3), a polyester compound with a terminal diol exemplified below can be used as a raw material.

[0071]

Chemical formula

[0072] To obtain the polyester soft segment of the repeating unit b5 in the general formula (2) or (3), a polyester compound with a terminal diol exemplified below can be used as a raw material.

[0073]

Chemical formula

[0074] To obtain the soft segment combining a polyether and a polyester of the repeating unit b6 in the general formula (2) or (3), a compound combining a polyether with a terminal diol and a polyester exemplified below can be used as a raw material.

[0075]

Chemical formula

[0076] The silicone pendant polyurethane resin having the structure represented by a1 or a2 in General Formula (1) or (3) used in the stretchable film of the present invention can be formed by using a diol compound having a silicon-containing group represented by General Formula (a)-1’ or (a)-2’ as a raw material and reacting these with an isocyanate compound. Furthermore, in addition to these, any one of a polycarbonate compound, a polyether compound, and a polyester compound having a hydroxy group at the terminal, or a combination thereof can be added as a chain extender and formed by reaction with an isocyanate compound.

[0077] Examples of the isocyanate compound that reacts with the above-described diol compound having a silicon-containing group, polyether compound, polycarbonate compound, and polyester compound having a hydroxy group at the terminal include, but are not limited to, the following.

[0078]

Chemical formula

[0079]

Chemical formula

[0080] The silicone polyurethane of the present invention can make the terminal of the silicone urethane a maleimide group by reacting the diol compound and the isocyanate compound as described above, and further a maleimide compound that binds to a hydroxy group, a carboxyl group, an amino group, or an isocyanate group. Examples of the maleimide compound that binds to a hydroxy group, a carboxyl group, an amino group, or an isocyanate group include, but are not limited to, the following. By using such a maleimide compound, the maleimide structure in General Formula (1) or (3) can be introduced.

[0081]

Chemical formula

[0082]

Chem.

[0083]

Chem.

[0084]

Chem.

[0085]

Chem.

[0086]

Chem.

[0087] It is also possible to make the polymer terminal an amino group by using a diamine compound in the polymerization of a urethane polymer, and then react this amino group with maleic anhydride to make the terminal a maleimide.

[0088] Among the above maleimide compounds, in particular, by reacting a compound having a maleimide group and an isocyanate group with a diol compound having a silicon-containing group represented by the general formula (a)-1' or (a)-2', a polyether compound having a hydroxy group at the terminal, a polycarbonate compound, or a polyester compound, a urethane bond is formed to obtain a silicone polyurethane having a maleimide group at the terminal, represented by the general formula (1) or (3). In addition, by reacting a maleimide compound having a hydroxy group or a maleimide compound having an amino group with an isocyanate compound, a urethane bond and a urea bond are respectively formed to obtain a silicone polyurethane having a maleimide group at the terminal, represented by the general formula (1) or (3). A silicone polyurethane having a maleimide group at the terminal can also be obtained by subjecting a maleimide compound having a carboxyl group to an esterification reaction with a diol compound having a silicon-containing group represented by the general formula (a)-1' or (a)-2', a polyether compound having a hydroxy group at the terminal, a polycarbonate compound, or a polyester compound. In this case, the maleimide compound having a carboxyl group can form an amide bond while undergoing decarboxylation in the reaction with isocyanate to obtain a silicone polyurethane having a maleimide group at the terminal.

[0089] Since the above isocyanate compound has high reactivity with a diol compound having a silicon-containing group represented by the general formula (a)-1' or (a)-2', a polyether compound having a hydroxy group at the terminal, a polycarbonate compound, a polyester compound, or a maleimide compound having a hydroxy group or an amino group, it may be difficult to control. In addition, since the isocyanate compound may react with moisture in the air during storage and the isocyanate group may be deactivated, sufficient care such as sufficiently preventing humidity is required for storage. Therefore, in order to prevent these events, a compound having a blocked isocyanate group in which the isocyanate group is protected by a substituent may be used.

[0090] A blocked isocyanate group is one in which the blocking group is deprotected by heating to form an isocyanate group. Specifically, examples include isocyanate groups substituted with alcohol, phenol, thioalcohol, imine, ketimine, amine, lactam, pyrazole, oxime, β-diketone, and the like.

[0091] In order to lower the deprotection temperature of the blocked isocyanate group, a catalyst can also be added. Known catalysts include organotin such as dibutyltin dilaurate, bismuth salts, and zinc carboxylates such as zinc 2-ethylhexanoate and zinc acetate.

[0092] In particular, Japanese Patent Application Laid-Open No. 2012-152725 shows that by including zinc α,β-unsaturated carboxylate as a blocked isocyanate dissociation catalyst, it is possible to lower the temperature of the deprotection reaction.

[0093] Also, a compound having an amino group can be added. When an isocyanate group reacts with an amino group, a urea bond is formed. The urethane bond and urea bond portions are called hard segments, and their strength is increased by these hydrogen bonds. Therefore, it is possible to increase the strength not only by the urethane bond but also by adding a urea bond thereto.

[0094] The silicone polyurethane resin used for forming the stretchable film of the present invention preferably has a weight average molecular weight of 500 or more. Further, the upper limit value of the weight average molecular weight of the silicone polyurethane resin is preferably 500,000 or less. If it is such a thing, it can be suitably used for the stretchable film of the present invention. The weight average molecular weight (Mw) indicates a value in terms of polystyrene conversion by GPC.

[0095] As the stretchable film material for forming the stretchable film of the present invention, it is characterized by containing a silicone polyurethane having a maleimide group at the terminal. However, it is also possible to mix a polyurethane having a (meth)acrylate group at the terminal, a silicone polyurethane, or a polyurethane having a maleimide group at the terminal without silicone. At this time, the mixing ratio is preferably such that the ratio of the silicone polyurethane having a maleimide group at the terminal is at least 10% or more, more preferably 20% or more, and even more preferably 30% or more, by weight. As described in Non-Patent Document 1 mentioned above, radicals are generated from the maleimide group by light irradiation, and the crosslinking and polymerization of the (meth)acrylate group proceed. By mixing a silicone polyurethane having a maleimide group, a silicone polyurethane having a (meth)acrylate group, and a polyurethane having a maleimide group at the terminal without silicone, it is possible to balance stretchability and strength.

[0096] Examples of the silicone polyurethane (meth)acrylate to be mixed in this case include polyurethanes in which silicone is introduced into the main chain or side chain. From the viewpoints of high strength and high stretchability, the side chain silicone type described in Patent Documents 4, 5, and 6 mentioned above can be preferably used.

[0097] <Characteristics of the stretchable film> The surface of the stretchable film may be flat, may have irregularities, may have holes, or may be fibrous. In order to ensure sufficient skin respiration when attached to the skin, it is preferable that there are holes or it is fibrous. As described in Japanese Patent Application Laid-Open No. 2020-105485, when there are irregularities, superhydrophobic properties like those of a lotus leaf can also be exhibited.

[0098] In addition, the stretchable film of the present invention preferably has an elongation rate of 20 to 1000% in the tensile test defined in JIS K 6251. With such an elongation rate, it can be particularly preferably used as a substrate film for stretchable wiring.

[0099] In addition, the stretchable film of the present invention is preferably used as a film that contacts a stretchable conductive wiring or a film for protecting a device. The stretchable film of the present invention can be particularly preferably used for such applications.

[0100] The stretchable film of the present invention as described above has stretchability, has excellent strength superior to polyurethane, has hysteresis, and has a film surface with excellent water repellency comparable to that of silicone, thus becoming a stretchable film.

[0101] <Method for forming a stretchable film> In addition, the present invention provides a method for forming a stretchable film, comprising: a step of applying a stretchable film material containing a silicone polyurethane having a maleimide group at least at the terminal; and a step of curing the stretchable film material by heating and / or light irradiation. A method for forming a stretchable film including these steps is provided.

[0102] Here, the stretchable film material containing the silicone polyurethane is preferably a stretchable film material containing a maleimide group-terminated silicone polyurethane resin having a structure represented by the following general formula (1).

Chemical formula

[0103] Note that the viscosity of the stretchable film material (mixed solution) can be adjusted as appropriate. When making the viscosity low, for example, an organic solvent is mixed, and when making the viscosity high, for example, a filler such as silica is mixed.

[0104] As the organic solvent, an organic solvent having a boiling point in the range of 115 to 200 °C at atmospheric pressure is preferred. Specifically, 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butenyl acetate, isoamyl acetate, phenyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and one or more selected therefrom are preferably used.

[0105] As the ratio of the number of moles of the hydroxy group and the isocyanate group in the stretchable film material (mixture), it is preferable that the number of moles of the hydroxy group and the isocyanate group is the same, but it may be slightly more of the hydroxy group or the isocyanate group. When there are more isocyanate groups, since the polymer terminal is a highly reactive isocyanate group, it is reacted with water or alcohol. When there are more hydroxy groups, the polymer terminal is a hydroxy group.

[0106] When the cured product of the stretchable film material is formed in a state where the number of moles of the hydroxy group is larger than that of the isocyanate group as described above, a urethane bond may be formed only on one side of the diol compound represented by the general formulas (a’)-1 and (a’)-2 at the polymer terminal.

[0107] [Chemical formula] (In the formula, R 1 ~R 7 、X, q, and r are as described above.)

[0108] In addition to the above methods, a film can also be formed by a prepolymer method in which a compound containing a hydroxy group and an isocyanate compound are mixed to form a polymer (prepolymer), and then a compound containing a hydroxy group or a compound containing an isocyanate group is additionally mixed and heat-cured. When forming a prepolymer, the molecular weight is increased by using an excess of either the compound containing a hydroxy group or the isocyanate compound. The amount of unreacted residual isocyanate can be reduced compared to the one-shot method in which a compound containing a hydroxy group or an isocyanate compound is mixed to form a film at once.

[0109] The present invention is characterized by curing by a crosslinking reaction of maleimide groups, but crosslinking by urethane bonds can also be used in combination. To perform crosslinking and curing of urethane bonds, a compound having three or more hydroxy groups or isocyanate groups in one molecule is added to form a silicone polyurethane.

[0110] The heating temperature during curing is preferably in the range of room temperature to 200°C. More preferably, it is in the range of 40 to 160°C, and the time is preferably in the range of 5 seconds to 60 minutes.

[0111] Specifically, in the case of polyether-containing silicone pendant polyurethane maleimide, for example, a polyether diol compound for obtaining the b1 unit in the above general formula (2), and a silicone pendant diol compound for obtaining the a1 and a2 units are mixed with a protected or unprotected isocyanate compound, a hydroxy group, an amino group, and a maleimide compound having an isocyanate group, and polymerized to synthesize a polyether-containing silicone pendant polyurethane maleimide having a maleimide group at the polymer terminal.

[0112] The polyether-containing silicone pendant polyurethane maleimide can be crosslinked by light irradiation or radicals. When maleimides couple with each other by light, radical crosslinking may occur, and a radical generator can also be added separately. As radical generators, there are thermal radical generators that generate radicals by thermal decomposition and photo radical generators that generate radicals by light irradiation.

[0113] Examples of thermal radical generators include azo radical generators and peroxide radical generators. Examples of azo radical generators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2'-azobis(2-methylpropionate), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(cyclohexane-1-carbonitrile), 4,4'-azobis(4-cyanovaleric acid), etc. Examples of peroxide radical generators include benzoyl peroxide, decanoyl peroxide, lauroyl peroxide, succinic peroxide, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, etc.

[0114] Examples of the photo radical generator include acetophenone, 4,4'-dimethoxybenzyl, benzyl, benzoin, benzophenone, 2-benzoylbenzoic acid, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, benzoin isobutyl ether, 4-benzoylbenzoic acid, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, methyl 2-benzoylbenzoate, 2-(1,3-benzodioxol-5-yl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, 4,4'-dichlorobenzophenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,4-diethylthioxanthen-9-one, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, 1,4-dibenzoylbenzene, 2-ethylanthraquinone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 2-isonitroso-propiophenone, 2-phenyl-2-(p-toluenesulfonyloxy)acetophenone (BAPO), and camphorquinone.

[0115] Note that the addition amount of the thermal or photo radical generator is preferably in the range of 0.1 to 50 parts by mass with respect to 100 parts by mass of the resin contained in the stretchable film material.

[0116] In addition, a crosslinking agent having a plurality of (meth)acrylates, thiols, and maleimides can also be added. Thereby, the crosslinking efficiency can be improved.

[0117] To the stretchable film material, monomers having an alkyl group or an aryl group, or monomers having a silicon-containing group or an alkyl group or an aryl group substituted with fluorine can also be added. Thereby, the viscosity of the solution can be reduced, and a more thin stretchable film can be formed. If these monomers have a polymerizable double bond, they are immobilized in the film during the curing of the film.

[0118] Monomers having an alkyl group or an aryl group include, for example, isobornyl acrylate, lauryl acrylate, tetradecyl acrylate, stearyl acrylate, isostearyl acrylate, behenyl acrylate, adamantane acrylate, phenoxyethylene glycol acrylate, phenoxydiethylene glycol acrylate, and 2- to 6-functional acrylates.Examples of bifunctional acrylates include 1,6 - hexanediol diacrylate, 1,9 - nonanediol diacrylate, isononanediol diacrylate, 1,10 - decanediol diacrylate, neopentyl glycol diacrylate, 2 - hydroxy - 3 - methacryloylpropyl acrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, polytetramethylene glycol diacrylate, polyethylene - polypropylene glycol diacrylate, dioxane glycol diacrylate, tricyclodecane dimethanol diacrylate, 9,9 - bis[4-(2 - hydroxyethoxy)phenyl]fluorene diacrylate, ethoxylated bisphenol A diacrylate, propoxylated bisphenol A diacrylate, ethoxylated - propoxylated bisphenol A diacrylate. Examples of trifunctional acrylates include trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, glycerin triacrylate, ethoxylated glycerin triacrylate, propoxylated glycerin triacrylate, tris(2 - acryloxyethyl)isocyanurate, caprolactone - modified tris(2 - acryloxyethyl)isocyanurate, pentaerythritol triacrylate. Examples of tetrafunctional acrylates include pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated ditrimethylolpropane tetraacrylate, propoxylated ditrimethylolpropane tetraacrylate. Examples of 5 - 6 functional acrylates include dipentaerythritol polyacrylate, ethoxylated dipentaerythritol polyacrylate, propoxylated dipentaerythritol polyacrylate. Also, monomers obtained by changing the above - mentioned acrylates to methacrylates can be used.

[0119] When forming a stretchable film using a compound having a maleimide group at the end, it is also possible to cure by combining thermosetting and photocuring. For example, the base stretchable film can be formed by thermosetting, and the stretchable film with the uneven pattern thereon can also be formed by photocuring. The advantages of photocuring are that heating is not always necessary and curing can be achieved in a short time. The disadvantage is that curing cannot be performed on the parts where light does not reach. By combining thermosetting and photocuring, a curing method that takes advantage of each can be selected.

[0120] When curing a compound having a maleimide group at the end by heating, the heat curing can be carried out, for example, by a hot plate, in an oven, or by irradiation with far-infrared rays. The heating conditions are preferably 30 to 150 °C for 10 seconds to 60 minutes, and more preferably 50 to 120 °C for 30 seconds to 20 minutes. The baking environment can be in the air, in an inert gas, or in a vacuum.

[0121] When curing a compound having a maleimide group at the end by light irradiation, the curing by light irradiation is preferably carried out with light having a wavelength of 200 to 500 nm. As the light source, for example, a halogen lamp, a xenon lamp, an excimer laser, a metal halide lamp, an LED, etc. can be used. Also, irradiation with an electron beam may be used. The irradiation amount is preferably in the range of 1 mJ / cm 2 ~100 J / cm 2 .

[0122] The stretchable film of the present invention can be used not only as a single self-supporting film but also formed on fibers or on a membrane film.

[0123] <Examples of Use of the Stretchable Film of the Present Invention> Here, Fig. 1 shows an example of the use of the stretchable film of the present invention. Fig. 1 is a schematic view of an electrocardiograph 1 formed on a stretchable film 6 of the present invention as seen from the biological electrode side. As shown in Fig. 1, the electrocardiograph 1 has three biological electrodes 2 connected by wiring 3 through which an electrical signal is conducted, and is connected to a center device 4. The electrocardiograph 1 is provided with an adhesive portion 5 around the biological electrode 2, and the electrocardiograph 1 is as described in Patent Document 1. In the center device 4, a device for processing biological signals, an antenna for data communication with a peripheral smartphone, a battery, etc. are mounted.

[0124] As the material of the wiring 3, generally metals such as gold, silver, platinum, titanium, stainless steel, etc. and conductive materials such as carbon are used. In addition, in order to exhibit stretchability, as described in Patent Document 1, it can also be a bellows-shaped wiring, or the conductive material powder or wire-shaped conductive material described above can be pasted on the stretchable film, or the conductive ink containing the above-mentioned conductive material can be printed, or a conductive cloth in which the conductive material and the fiber are composite can be used to form the wiring 3.

[0125] Since the electrocardiograph 1 needs to be attached to the skin, the adhesive portion 5 is arranged around the biological electrode 2. In addition, when the biological electrode 2 has adhesiveness, the peripheral adhesive portion 5 is not necessarily required.

[0126] This electrocardiograph 1 is fabricated on the stretchable film 6, which is the stretchable film of the present invention, as shown in Fig. 1. When printing is performed on the stretchable film 6 by screen printing or the like, the stretchable film of the present invention by maleimide crosslinking has good plate release. When the plate release is poor, ink separation occurs when the plate is separated, and the ink may not be transferred onto the stretchable film, which is not preferable.

[0127] Furthermore, the stretchable wiring 3 and the center device 4 can also be covered with the stretchable film of the present invention. In this case, after attaching the wiring 3 and the center device 4 on the stretchable film 6, it is covered with the stretchable film of the present invention and cured. In order to cover a center device or wiring with a certain height, it is preferable to cover the stretchable material of the present invention by inkjet or spray coating.

[0128] When the center device 4 is removable, it is not necessary to cover the center device with a stretchable film in continuity with the stretchable substrate.

Example

[0129] Hereinafter, the present invention will be specifically described using examples and comparative examples, but the present invention is not limited thereto. The weight average molecular weight (Mw) and dispersity (Mw / Mn) represent values in terms of polystyrene conversion by GPC.

[0130] (Synthesis Example 1) Under a nitrogen stream, 100 g of propylene glycol monoethyl ether acetate (PGMEA), 0.2 mol of polytetramethylene ether glycol with Mw 1000, 0.1 mol of silicone diol 1, 0.4 mol of isophorone diisocyanate, and 0.001 mol of dibutyltin dilaurate were mixed in a reaction vessel of a planetary mixer and stirred for 30 minutes. Then, the temperature was raised to 90 °C and stirring was continued for 6 hours. After cooling, 0.2 mol of N-(2-hydroxyethyl) maleimide was added dropwise and mixed. The temperature was raised to 90 °C again and stirring was continued for 1 hour. PGMEA was evaporated under vacuum to obtain silicone polyurethane maleimide 1 with the following weight average molecular weight and dispersity.

[0131]

Chemical formula

[0132] Silicone polyurethane maleimide 1: Mw = 5,400, Mw / Mn = 1.65

Chemical formula

[0133] (Synthesis Examples 2 to 20, Comparative Synthesis Examples 1 to 2) In the same manner as in Synthesis Example 1, silicone polyurethane maleimide 2 to 20, silicone polyurethane acrylate 1 with acrylated ends, and comparative polyurethane maleimide 1 without added silicone diol were synthesized.

[0134]

Chemical formula

[0135]

Chemical formula

[0136]

Chemical formula

[0137]

Chemical formula

[0138]

Chemical formula

[0139]

Chemical formula

[0140]

Chemical formula

[0141]

Chemical formula

[0142]

Chemical formula

[0143] [Chemistry]

[0144] The photoinitiator 1 compounded as an additive in the stretchable film materials 6 to 13, 22, 23, and the comparative stretchable film material 1 is shown below. Photoinitiator 1: Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide

[0145] The monomers having an alkyl group compounded in the stretchable film materials 6 to 13 are shown below. Monomer having an alkyl group: Isobornyl acrylate

[0146] [Examples, Comparative Examples] A silicone polyurethane having a maleimide group at the terminal and, optionally, a photoinitiator were mixed with the composition described in Table 1 to prepare stretchable film materials 1 to 23 and comparative stretchable film materials 1 and 2 (composition for forming a stretchable film).

[0147] [Table 1]

[0148] (Production of Stretchable Film) The stretchable film materials shown in Table 2 heated to 40 °C were applied on a Teflon (registered trademark) film with a slit coater, and irradiated with light of 500 mJ / cm 2 from a 1,000 W xenon lamp in a nitrogen atmosphere to be cured, thereby producing a stretchable film.

[0149] (Measurement of Film Thickness, Contact Angle, Elongation Rate, and Strength) The film thickness and the contact angle of water on the surface of the cured stretchable films (Examples 1 to 23) and the stretchable films of the comparative examples (Comparative Examples 1 and 2) were measured, and the elongation rate (elongation) and strength were measured by a method according to JIS K 6251. The results are shown in Table 2.

[0150] [Table 2]

[0151] As shown in Table 2, in the stretchable film formed by curing a stretchable film material containing a silicone polyurethane having a maleimide group at least at its terminal according to the present invention, a stretchable film having high water repellency, strength, and stretchability was obtained.

[0152] On the other hand, in the film formed by curing a silicone polyurethane having no maleimide group as in Comparative Example 1, the strength was insufficient, and in the film formed by curing a polyurethane having a terminal maleimide having no silicone as in Comparative Example 2, both the water repellency and stretchability were low.

[0153] From the above, it is clear that a stretchable film formed by curing a stretchable film material containing a silicone polyurethane having a maleimide group at least at its terminal according to the present invention has excellent stretchability and strength, excellent water repellency on the film surface, and excellent characteristics as a stretchable wiring-printable film used for wearable devices and the like. In addition, the silicone polyurethane of the present invention can form a film alone and does not necessarily require a reaction initiator or a solvent, so it has merits such as being environmentally friendly.

[0154] Note that the present invention is not limited to the above-described embodiments. The above-described embodiments are examples, and any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits the same operational effects is included in the technical scope of the present invention.

Explanation of Reference Numerals

[0155] 1... Electrocardiograph, 2... Biopotential electrode, 3... Wiring, 4... Central device, 5... Adhesive part, 6... Stretchable film

Claims

1. A silicone polyurethane having a maleimide group at least at the ends of the main chain, wherein the silicone polyurethane having a maleimide group at the ends has silicone in the side chains.

2. The silicone polyurethane according to Claim 1, wherein the silicone polyurethane having a maleimide group at the ends has a structure represented by the following general formula (1). 【Chemical 1】 (wherein, R １ , R ２ , R ３ are the same or different linear, branched, or cyclic alkyl groups having 1 to 6 carbon atoms, phenyl groups, or 3,3,3-trifluoropropyl groups. R ４ are the same or different linear, branched, or cyclic alkyl groups having 1 to 6 carbon atoms, phenyl groups, 3,3,3-trifluoropropyl groups, or -(OSiR １ R ２ )( ｓ -OSiR １ R ２ R ３ groups. s is an integer in the range of 0 to 100. R ５ is a hydrogen atom, or a linear or branched alkyl group having 1 to 4 carbon atoms, R ６ is a single bond, a methylene group, or an ethylene group, R ７ is a hydrogen atom or a methyl group. R ８ , R ９ are hydrogen atoms, linear, branched, or cyclic alkyl groups having 1 to 6 carbon atoms, alkenyl groups having 2 to 10 carbon atoms, alkynyl groups having 2 to 10 carbon atoms, or aryl groups having 6 to 10 carbon atoms, and R ８ and R ９ may combine to form a ring. X is a linear or branched alkylene group having 3 to 7 carbon atoms and may contain an ether group, Y is a linear, branched, or cyclic alkylene group having 1 to 40 carbon atoms and may have an ether bond, an ester bond, an amide bond, a urethane bond, a urea bond, and may have a phenylene group. q and r are integers in the range of 1 to 20. a1 and a2 are the ratios of the repeating units, and are in the range of 0 ≦ a1 ≦ 1.0, 0 ≦ a2 ≦ 1.0, and 0 < a1 + a2 ≦ 1.

0. n is an integer of 1 to 4.)

3. The silicone polyurethane according to Claim 1 or Claim 2, wherein the silicone polyurethane having a maleimide group at the ends has a soft segment selected from polyethers, polyesters, and polycarbonates.

4. The silicone polyurethane according to Claim 3, wherein the soft segment selected from polyethers, polyesters, and polycarbonates is represented by the following general formula (2). 【Chemical 2】 (wherein, R １０ ~R ２１ are the same or different linear, branched or cyclic alkylene groups having 2 to 12 carbon atoms. m is the same or different and is 1 to 200. b1, b2, b3, b4, b5, b6 are the ratios of the repeating units, and are in the range of 0 ≦ b1 < 1.0, 0 ≦ b2 < 1.0, 0 ≦ b3 < 1.0, 0 ≦ b4 < 1.0, 0 ≦ b5 < 1.0, 0 ≦ b6 < 1.0, 0 < b1 + b2 + b3 + b4 + b5 + b6 < 1.0.)

5. A stretchable film formed by curing a stretchable film material containing the silicone polyurethane according to any one of Claims 1 to 4.

6. The stretchable film according to Claim 5, wherein the stretchable film has an elongation rate in the range of 20 to 1000% in a tensile test defined in JIS K 6251.

7. A step of applying a stretchable film material containing the silicone polyurethane according to any one of Claims 1 to 4, and A step of curing the stretchable film material by heating and / or light irradiation A method for forming a stretchable film, characterized by including these steps.

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