Curable composition for imprinting, pattern formation method, and part production method

Abstract

This curable composition for imprinting is a composition containing: a component (A) that is a bifunctional (meth)acrylate monomer represented by general formula (1); and a component (B) that is a bifunctional urethane (meth)acrylate monomer represented by general formula (2).

Description

Curable composition for imprints, pattern formation method, and part manufacturing method

[0001] Some aspects of the present invention relate to a curable composition for imprints. Other aspects of the present invention relate to a pattern formation method using the curable composition and a method for manufacturing a part using the method.

[0002] Imprint lithography has the advantage of being able to produce fine patterns at lower cost than photolithography, and has recently attracted attention as a microfabrication technology. In general imprint lithography, a curable composition is applied to a substrate to form a curable composition layer, and then the curable composition layer is brought into contact with a mold having a concave-convex pattern. The curable composition layer is then cured by heat or light to obtain a molded product to which the concave-convex pattern has been transferred.

[0003] The curable composition used in imprint lithography is required to be able to fill the concave-convex pattern of the mold in order to precisely transfer the concave-convex pattern of the mold. Furthermore, molded articles produced by imprint lithography are required to have various properties, such as mechanical strength, depending on their intended use. Since these required properties mainly depend on the curable composition used, various curable compositions for imprints have been investigated.

[0004] Japanese Patent Application Laid-Open No. 2002-107501

[0005] Patent Document 1 discloses that molded articles with excellent hardness can be obtained by using a curable composition containing as a main component a polyfunctional (meth)acrylate monomer having 4 to 6 polymerizable groups. However, such molded articles obtained from curable compositions containing as a main component a polyfunctional (meth)acrylate monomer tend to crack easily when released from the mold or when the molded article is physically processed. Therefore, there is a demand for a curable composition for imprints that can produce molded articles that are less susceptible to cracking.

[0006] As a result of intensive investigations to solve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by using a composition comprising a combination of specific components as a curable composition for imprints, and have thus completed several aspects of the present invention.

[0007] One embodiment of the present invention is a curable composition for imprints comprising: component (A): a bifunctional (meth)acrylate monomer; and component (B): a bifunctional urethane (meth)acrylate monomer, wherein the content ratio of component (A) to component (B) is 20 to 80:80 to 20 in mass ratio.

[0008] The component (A) is represented by the following general formula (1).

[0009]

[0010] In the above general formula (1), R １ R each independently represents a hydrogen atom or a methyl group. ２ represents a branched alkylene group having 3 to 50 carbon atoms which may have a substituent. At least one methylene group contained in the branched alkylene group is -O-, -CO-, -S-, -SO-, or -SO ２ -, -NH- and -NR Ｎ１ - may be substituted with at least one heteroatom-containing group selected from the group consisting of Ｎ１ represents a monovalent group selected from the group consisting of a linear alkyl group having 1 to 10 carbon atoms, a branched alkyl group having 3 to 10 carbon atoms, a cyclic alkyl group having 3 to 10 carbon atoms, and an aryl group having 6 to 10 carbon atoms.

[0011] The component (B) is represented by the following general formula (2).

[0012]

[0013] In the above general formula (2), R ３ R each independently represents a hydrogen atom or a methyl group. ４each independently represents a linear alkylene group having 2 to 30 carbon atoms which may have a substituent, or a branched alkylene group having 3 to 30 carbon atoms which may have a substituent. At least one methylene group contained in the linear or branched alkylene group is -O-, -CO-, -S-, -SO-, or -SO ２ -, -NH- and -NR Ｎ２ - may be substituted with at least one heteroatom-containing group selected from the group consisting of Ｎ２ represents a monovalent group selected from the group consisting of a linear alkyl group having 1 to 10 carbon atoms, a branched alkyl group having 3 to 10 carbon atoms, a cyclic alkyl group having 3 to 10 carbon atoms, and an aryl group having 6 to 10 carbon atoms. Each Z independently represents -O-CO-NH- or -NH-CO-O-. R ５ represents a divalent group selected from the group consisting of an optionally substituted linear alkylene group having 1 to 50 carbon atoms, an optionally substituted branched alkylene group having 3 to 50 carbon atoms, and an optionally substituted cyclic alkylene group having 3 to 50 carbon atoms.

[0014] Another aspect of the present invention is a pattern forming method using the above-mentioned curable composition for imprints.

[0015] Another aspect of the present invention is a method for manufacturing a component using the above-described pattern formation method.

[0016] The curable composition for imprints according to one embodiment of the present invention tends to be able to suppress the occurrence of cracks in molded articles.

[0017] The present invention will be described in detail below.

[0018] As used herein, "(meth)acrylate" refers to both "acrylate" and "methacrylate." Similarly, "(meth)acryloyl" refers to both "acryloyl" and "methacryloyl." Similarly, "(meth)acrylic" refers to both "acrylic" and "methacrylic."

[0019] In this specification, the term "polymerizable group" refers to a radically polymerizable group such as a (meth)acryloyl group, a vinyl group, an allyl group, a homoallyl group, a propargyl group, and a homopropargyl group.

[0020] <1> Curable composition for imprints One aspect of the present invention is a curable composition for imprints containing a bifunctional (meth)acrylate monomer represented by the above general formula (1) and a bifunctional urethane (meth)acrylate monomer represented by the above general formula (2).

[0021] <Component (A): Bifunctional (meth)acrylate Monomer> The curable composition for imprints of one embodiment of the present invention contains a bifunctional (meth)acrylate monomer represented by the above general formula (1) (hereinafter also referred to as “component (A)”).

[0022] R in general formula (1) １ each independently represents a hydrogen atom or a methyl group.

[0023] R in general formula (1) ２ represents a branched alkylene group having 3 to 50 carbon atoms, which may have a substituent. Examples of the branched alkylene group include alkylene groups in which at least one hydrogen atom of a linear alkylene group, such as a methylene group, ethylene group, n-propylene group, n-butylene group, n-octylene group, n-nonylene group, or n-decylene group, has been substituted with a linear alkyl group, such as a methyl group, ethyl group, or n-propyl group. Examples of the branched alkylene group include groups represented by the following formulas and combinations thereof.

[0024]

[0025] R ２ At least one methylene group contained in the branched alkylene group is —O—, —CO—, —S—, —SO—, or —SO ２ -, -NH- and -NR Ｎ１ - may be substituted with at least one heteroatom-containing group selected from Ｎ１represents a monovalent group selected from the group consisting of a linear alkyl group having 1 to 10 carbon atoms, a branched alkyl group having 3 to 10 carbon atoms, a cyclic alkyl group having 3 to 10 carbon atoms, and an aryl group having 6 to 10 carbon atoms. The methylene group substituted with a heteroatom-containing group is preferably not a methylene group contained in a branch of a branched alkylene group, but is preferably a methylene group contained in the main chain of a branched alkylene group. When the branch does not have a heteroatom-containing group, the number of heteroatoms such as oxygen atoms can be reduced, which tends to improve the dry etching resistance of the cured product. The same applies to the general formulas (1-1) to (1-3), (2), and (2-1) described below. In this specification, the "main chain" in component (A) and component (B) refers to the carbon chain connecting two (meth)acrylic groups. R Ｎ１ Examples of the linear alkyl group of R include alkyl groups such as a methyl group, an ethyl group, an n-butyl group, and an n-hexyl group. Ｎ１ Examples of the branched alkyl group include an isopropyl group, an isobutyl group, a t-butyl group, and a 2-ethylhexyl group. Ｎ１ Examples of the cyclic alkyl group include a cyclopropyl group, a cyclohexyl group, a cyclooctyl group, an adamantyl group, and an isobornyl group. Ｎ１ Examples of the aryl group in R include a phenyl group and a naphthyl group. From the viewpoint of the stability of component (A), ２ Among the methylene groups contained in the branched alkylene group, it is preferred that the methylene group directly bonded to the (meth)acryloyloxy group of the general formula (1) is not substituted with a heteroatom-containing group, and the first methylene group of the branch of the branched alkylene group is not substituted with a heteroatom-containing group.

[0026] R ２The branched alkylene group represented by the formula (I) has the above-described branch. In addition to the branch, it may have a substituent (hereinafter also referred to as "substituent R"), but it is preferable that it does not have one. Examples of the substituent R include a hydroxy group, an alkoxy group, an aryloxy group, a cyano group, a nitro group, a halogen atom, an amino group, a silyl group, a carboxyl group, an alkyloxycarbonyl group, an aryloxycarbonyl group, an acyl group, an alkylsulfanyl group, an arylsulfanyl group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, and combinations thereof. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the amino group and the silyl group include unsubstituted groups (respectively, -NH ２ and -SiH ３ ) and groups in which the hydrogen atoms contained in the unsubstituted groups are substituted with alkyl groups and / or aryl groups. When the branched alkylene group does not have a substituent, the number of heteroatoms such as oxygen atoms can be reduced, which tends to improve the dry etching resistance of the cured product. The same applies to the general formulae (1-1) to (1-3), (2) and (2-1) described later. R ２ When the branched alkylene group represented by the formula (I) has a substituent R, the number of carbon atoms of the branched alkylene group is the number of carbon atoms including the number of carbon atoms of the substituent R.

[0027] As component (A), two or more types of bifunctional (meth)acrylate monomers may be used in combination.

[0028] An example of the component (A) is a (meth)acrylate monomer represented by the following general formula (1-1).

[0029]

[0030] In the above general formula (1-1), R １ is R in general formula (1). １ represents a group selected from the same options as ６represents a branched alkylene group having 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms. A methylene group contained in the branched alkylene group is not substituted with a heteroatom-containing group. The branched alkylene group may have a substituent in addition to the branch. Examples of the substituent include groups selected from the same options as the substituent R above.

[0031] Examples of the (meth)acrylate monomer represented by general formula (1-1) include Light Ester NP, Light Acrylate NP-A, and Light Acrylate MPD-A manufactured by Kyoeisha Chemical Co., Ltd.; NK Ester A-NPG and NK Ester NPG manufactured by Shin-Nakamura Chemical Co., Ltd.; and KAYARAD NPGDA manufactured by Nippon Kayaku Co., Ltd.

[0032] Examples of the (meth)acrylate monomer represented by the general formula (1-1) include (meth)acrylates represented by the following formula: １ is R in general formula (1) １ represents a group selected from the same options as

[0033]

[0034] An example of component (A) is a (meth)acrylate monomer having an ester bond other than a (meth)acryloyloxy group, specifically a (meth)acrylate monomer represented by the following general formula (1-2): In general formula (1-2), the methylene groups in the main chain of the branched alkylene group in general formula (1) are substituted with -O- and -CO-.

[0035]

[0036] In the above general formula (1-2), R １ is R in general formula (1). １ represents a group selected from the same options as ７ represents a linear alkylene group having 2 to 10 carbon atoms or a branched alkylene group having 3 to 10 carbon atoms. ７ When there are multiple R, they are selected independently. ８ represents a linear alkylene group having 2 to 10 carbon atoms or a branched alkylene group having 3 to 10 carbon atoms.７ and R ８ At least one of R is a branched alkylene group. ７ and R ８ The linear or branched alkylene group represented by the formula (I) may have a substituent, and the branched alkylene group may have a substituent in addition to the branch. Examples of the substituent include groups selected from the same options as the substituent R above. １２ Each of n represents an integer of 0 to 10, preferably 0 to 5. １２ At least one of R is an integer of 1 or more. ７ and R ８ Total (n １２ Of the (R × 2 + 1) linear alkylene groups or branched alkylene groups, preferably 1 / 3 or more, more preferably 1 / 2 or more, and even more preferably 2 / 3 or more are branched alkylene groups. ７ and R ８ Of the methylene groups contained in the main chain of the copolymer, preferably 5% or more, more preferably 8% or more, by number, of the methylene groups are branched. When the proportion of branched alkylene groups is within the above range, a cured product having an appropriate hardness tends to be obtained.

[0037] Examples of the (meth)acrylate monomer represented by the general formula (1-2) include Light Acrylate HPP-A manufactured by Kyoeisha Chemical Co., Ltd.; and KAYARAD FM-400, HX-220, and HX-620 manufactured by Nippon Kayaku Co., Ltd.

[0038] Examples of the (meth)acrylate monomer represented by the general formula (1-2) include (meth)acrylates represented by the following formula: １ is R in general formula (1) １ represents a group selected from the same options as

[0039]

[0040] An example of component (A) is a (meth)acrylate monomer having a branched oxyalkylene group, specifically a (meth)acrylate monomer represented by the following general formula (1-3): In general formula (1-3), a methylene group in the main chain of the branched alkylene group in general formula (1) is substituted with —O—.

[0041]

[0042] In the above general formula (1-3), R １ is R in general formula (1). １ represents a group selected from the same options as ９ represents a linear alkylene group having 2 to 10 carbon atoms or a branched alkylene group having 3 to 10 carbon atoms. ９ When there are multiple R, they are selected independently. ９ is a branched alkylene group. The linear alkylene group may have a substituent, and the branched alkylene group may have a substituent in addition to the branch. Examples of the substituent include groups selected from the same options as the substituent R above. １３ represents an integer of 1 to 20, preferably 2 to 10. ９ Total of n １３ Of the linear alkylene groups or branched alkylene groups, preferably 1 / 3 or more, more preferably 1 / 2 or more, and even more preferably 2 / 3 or more are branched alkylene groups. ９ Of the methylene groups contained in the main chain of the copolymer, preferably 5% or more, more preferably 8% or more, by number, of the methylene groups are branched. When the proportion of branched alkylene groups is within the above range, a cured product having an appropriate hardness tends to be obtained.

[0043] Examples of the (meth)acrylate monomer represented by general formula (1-3) include NK Ester APG-100, APG-200, APG-400, APG-700, A-1000PER, 3PGX, 9PG, and 1000PER manufactured by Shin-Nakamura Chemical Co., Ltd.; and Aronix M-220 manufactured by Toagosei Co., Ltd.

[0044] Examples of the (meth)acrylate monomer represented by the general formula (1-3) include (meth)acrylates represented by the following formula: １ is R in general formula (1) １ represents a group selected from the same options as

[0045]

[0046] Component (A) does not have a bond represented by —O—CO—NH— or —NH—CO—O—. Furthermore, from the viewpoint of crack resistance, it is preferable that component (A) does not have a ring structure such as an alicyclic ring or an aromatic ring.

[0047] The number of carbon atoms in component (A) is preferably 10 to 100, more preferably 10 to 50. The molecular weight of component (A) is preferably 800 or less, more preferably 700 or less. The lower limit of the molecular weight is not particularly limited, but is preferably, for example, 200 or more or 300 or more. Component (A) preferably accounts for 20 to 80 mass% of the monomer components, more preferably 30 to 70 mass%, and particularly preferably 40 to 60 mass%. By ensuring that the number of carbon atoms, molecular weight, or content of component (A) falls within the above ranges, the crosslink density of the molded product tends to be controlled and the hardness tends to be improved. Note that when the linear, branched, or cyclic alkylene group contained in component (A) has a substituent, the above carbon number includes the number of carbon atoms of the substituent.

[0048] <Component (B): Bifunctional Urethane (Meth)acrylate Monomer> The curable composition for imprints of one embodiment of the present invention contains a bifunctional urethane (meth)acrylate monomer represented by the above general formula (2) (hereinafter also referred to as “component (B)”).

[0049] In general formula (2), R ３ each independently represents a hydrogen atom or a methyl group.

[0050] In general formula (2), R ４ R each independently represents a linear alkylene group having 2 to 30 carbon atoms which may have a substituent, or a branched alkylene group having 3 to 30 carbon atoms which may have a substituent. ４ When R is a linear alkylene group, it preferably has 3 to 20 carbon atoms.４ When is a branched alkylene group, it preferably has 3 to 25 carbon atoms. The linear alkylene group may have a substituent, and the branched alkylene group may have a substituent in addition to the branch. Examples of the substituent include groups selected from the same options as for the substituent R.

[0051] R ４ At least one methylene group contained in the linear or branched alkylene group may be substituted with the heteroatom-containing group. ４ Among the methylene groups contained in the linear or branched alkylene group, it is preferred that the methylene group directly bonded to the (meth)acryloyloxy group of the general formula (2) or Z is not substituted with the heteroatom-containing group, and the first methylene group of the branch of the branched alkylene group is not substituted with a heteroatom-containing group.

[0052] In general formula (2), each Z independently represents —O—CO—NH— or —NH—CO—O—. That is, the nitrogen atom of Z is R ４ may be directly bonded to R ５ It may be directly bonded to

[0053] In general formula (2), R ５ represents a divalent group selected from the group consisting of a linear alkylene group having 2 to 50 carbon atoms, a branched alkylene group having 3 to 50 carbon atoms, and a cyclic alkylene group having 3 to 50 carbon atoms. ５ When R is a linear alkylene group, it preferably has 6 to 40 carbon atoms. ５ When R is a branched alkylene group, it preferably has 6 to 40 carbon atoms. ５ When R is a cyclic alkylene group, it preferably has 4 to 50 carbon atoms, and more preferably 6 to 40 carbon atoms. ５ The linear and branched alkylene groups represented by the formula (I) may have a substituent in addition to the branch, and the cyclic alkylene group may have a substituent. Examples of the substituent include groups selected from the same options as the substituent R. From the viewpoint of compatibility with other components, R ５is preferably a branched alkylene group, more preferably a branched alkylene group having at least one methyl group, and particularly preferably a trimethylhexamethylene group.

[0054] Component (B) can be synthesized by a conventional method, for example, by reacting an alkylene diisocyanate with a (meth)acrylate having a hydroxy group, or by reacting an alkylene diol with a (meth)acrylate having an isocyanate group.

[0055] As component (B), two or more types of bifunctional urethane (meth)acrylate monomers may be used in combination.

[0056] An example of component (B) is a urethane (meth)acrylate monomer having an oxyalkylene group, specifically a urethane (meth)acrylate monomer represented by the following general formula (2-1).

[0057]

[0058] In the above general formula (2-1), R ３ is R in general formula (2) ３ represents a group selected from the same options as １０ represents a linear or branched alkylene group. １０ When R is a linear alkylene group, it preferably has 2 to 10 carbon atoms, and more preferably 2 to 5 carbon atoms. １０ When n is a branched alkylene group, it preferably has 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms. The linear alkylene group may have a substituent, and the branched alkylene group may have a substituent in addition to the branch. Examples of the substituent include groups selected from the same options as the substituent R above. ２１ R each independently represents an integer of 1 to 20, preferably 1 to 10. ５ is R in general formula (2) ５ represents a group selected from the same options as

[0059] Examples of the urethane (meth)acrylate monomer represented by the general formula (2-1) include (meth)acrylates represented by the following formula: ３ is R in general formula (2) ３ represents a group selected from the same options as

[0060]

[0061] From the viewpoint of crack resistance, it is preferable that component (B) does not have a ring structure such as an alicyclic ring or an aromatic ring.

[0062] The number of carbon atoms in component (B) is preferably 10 to 100, more preferably 15 to 50. The molecular weight of component (B) is preferably 3,000 or less, more preferably 1,500 or less. There is no particular restriction on the lower limit of the molecular weight, but for example, it is preferably 300 or more or 400 or more. When the number of carbon atoms or molecular weight of component (B) is within the above range, the crosslink density of the molded product is controlled and the hardness tends to be improved. Note that when the linear, branched, or cyclic alkylene group contained in component (B) has a substituent, the above carbon number is the number of carbon atoms including the number of carbon atoms of the substituent.

[0063] The content of component (B) in the monomer components is preferably 15% by mass or more, more preferably 20% by mass or more. The upper limit is, for example, preferably 80% by mass or less, more preferably 60% by mass or less, and even more preferably 35% by mass or less. By ensuring that the content of component (B) falls within the above range, the occurrence of cracks in the molded product tends to be suppressed. Furthermore, since the viscosity of the composition falls within an appropriate range, the composition tends to be more easily filled into the mold.

[0064] The content ratio of component (A) to component (B) is 20 to 80:80 to 20 by mass. A content ratio of 30 to 70:70 to 30 is preferred, and 40 to 60:60 to 40 is more preferred. Having the content ratio of components (A) to (B) within the above range tends to suppress the occurrence of cracks in the molded product. This effect is presumably due to the urethane bonds in the monomer molecules of component (B) interacting with other monomer molecules through hydrogen bonding or other processes, thereby imparting toughness to the molded product. Furthermore, having the content ratio of components (A) to (B) within the above range tends to provide the composition with an appropriate viscosity, thereby improving the mold filling ability of the composition.

[0065] Preferred combinations of component (A) and component (B), when expressed by the above formula, include a combination of formula (1) and formula (2-1), a combination of formula (1-1) and formula (2), a combination of formula (1-1) and formula (2-1), a combination of formula (1-2) and formula (2), a combination of formula (1-2) and formula (2-1), a combination of formula (1-3) and formula (2), and a combination of formula (1-3) and formula (2-1). The above combinations of component (A) and component (B) tend to suppress the occurrence of cracks in the molded product.

[0066] <Component (C): Other Monomer> The curable composition for imprints of one embodiment of the present invention may further contain a monomer other than components (A) and (B) (hereinafter also referred to as "component (C)"). Examples of component (C) include a monofunctional monomer (hereinafter also referred to as "component (C1)"), a bifunctional monomer other than components (A) and (B) (hereinafter also referred to as "component (C2)"), and a polyfunctional monomer (hereinafter also referred to as "component (C3)"). Component (C1) has only one polymerizable group, component (C2) has only two polymerizable groups, and component (C3) has three or more polymerizable groups. Two or more of these monomers may be used in combination as component (C).

[0067] Examples of the component (C1) include a monofunctional (meth)acrylate monomer, (meth)acrylic acid, and a monofunctional vinyl monomer. Specific examples of the monofunctional (meth)acrylate monomer of component (C1) include linear alkyl (meth)acrylate monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, trifluoromethylethyl (meth)acrylate, and perfluorobutylethyl (meth)acrylate; branched alkyl (meth)acrylate monomers such as isopropyl (meth)acrylate, t-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; cyclic alkyl (meth)acrylate monomers such as cyclohexyl (meth)acrylate, cyclooctyl (meth)acrylate, isobornyl (meth)acrylate, and adamantyl (meth)acrylate; and aromatic (meth)acrylate monomers such as phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, and hydroxyphenyl (meth)acrylate. Specific examples of the monofunctional vinyl monomer of component (C1) include N-vinyl monomers such as N-vinyl-2-pyrrolidone, N-vinylformamide, and N-vinylacetamide; vinyl ether monomers such as butyl vinyl ether, 2-ethylhexyl vinyl ether, and cyclohexyl vinyl ether; vinyl ester monomers such as vinyl butyrate, vinyl laurate, and vinyl benzoate; and aromatic vinyl monomers such as styrene and vinyl naphthalene. Two or more types of monofunctional monomers may be used in combination as component (C1).

[0068] The number of carbon atoms in component (C1) is preferably 4 to 50, and more preferably 5 to 30. The molecular weight of component (C1) is preferably 1,000 or less, and more preferably 500 or less. Also, it is preferably 80 or more, and more preferably 100 or more. When the number of carbon atoms or molecular weight of component (C1) falls within the above range, the crosslink density of the molded product is controlled, and the hardness tends to be improved.

[0069] When the curable composition for imprints contains component (C1), its content is preferably 1 to 99% by mass, more preferably 5 to 50% by mass, and particularly preferably 10 to 40% by mass, based on the total amount of components (A) and (B), and the content ratio of component (C1) is preferably 95 to 50:5 to 50, more preferably 90 to 60:10 to 40, by mass. When the content or content ratio of component (C1) is within the above range, the crosslink density of the molded product tends to be controlled, and the hardness tends to be improved. Furthermore, the mold filling property tends to be improved.

[0070] Specific examples of component (C2) include linear alkylene di(meth)acrylate monomers such as 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 1,9-nonanediol di(meth)acrylate; linear oxyalkylene di(meth)acrylate monomers such as diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate; cyclic alkylene di(meth)acrylate monomers such as cyclohexanediol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, and tricyclodecanedimethanol di(meth)acrylate; aromatic di(meth)acrylate monomers such as di(meth)acrylates having a fluorene skeleton and di(meth)acrylates having a bisphenol skeleton; and divinyl monomers such as divinylbenzene and divinylnaphthalene. Two or more bifunctional monomers may be used in combination as component (C2).

[0071] Component (C2) does not have a bond represented by —O—CO—NH— or —NH—CO—O—, and does not have the structure represented by general formula (1).

[0072] The number of carbon atoms in component (C2) is preferably 10 to 100, and more preferably 10 to 50. The molecular weight of component (C2) is preferably 800 or less, and more preferably 700 or less. It is also preferably 200 or more, and more preferably 300 or more. When the curable composition for imprints contains component (C2), its content is preferably 1 to 20 mass% of the monomer components, and more preferably 5 to 10 mass%. When the number of carbon atoms, molecular weight, or content of component (C2) is within the above ranges, the crosslink density of the molded product is controlled, and the hardness tends to be improved.

[0073] Specific examples of component (C3) include polyfunctional (meth)acrylate monomers such as trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. Two or more polyfunctional monomers may be used in combination as component (C3).

[0074] The number of carbon atoms in component (C3) is preferably 10 to 100, more preferably 20 to 50. The molecular weight of component (C3) is preferably 1,000 or less, more preferably 500 or less, and preferably 200 or more, more preferably 250 or more. When the number of carbon atoms and molecular weight of component (C3) fall within the above ranges, the crosslink density of the molded product can be controlled, which tends to improve hardness.

[0075] When the curable composition for imprints contains component (C3), its content in the monomer components is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less. The lower limit is, for example, preferably 1% by mass or more. When the content of component (C3) is within the above range, the crosslink density of the molded product is improved while the viscosity of the composition is maintained low, and therefore, the molded product tends to have both high hardness and good mold fillability.

[0076] <Polymerization Initiator> The curable composition for imprints according to one embodiment of the present invention may further contain a polymerization initiator. Examples of the polymerization initiator include photoradical polymerization initiators having a skeleton such as an acetophenone skeleton, a benzyl ketal skeleton, or a phosphine oxide skeleton; photoionic polymerization initiators having a skeleton such as a sulfonium skeleton, an iodonium skeleton, or an acyloxime skeleton; thermal radical polymerization initiators such as azo compounds and peroxides; and thermal ionic polymerization initiators such as phenol resins, amine compounds, and carboxylic acid anhydrides. From the viewpoint of cure shrinkage, photoradical polymerization is preferred as a curing method for the curable composition, and a photoradical polymerization initiator is preferred as the polymerization initiator. The photoradical polymerization initiator may be any initiator that generates radicals when exposed to energy rays, as described below, and any initiator typically used in curable compositions for imprints can be used as appropriate.

[0077] When the curable composition for imprints contains a polymerization initiator, the content thereof is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 15 parts by mass, and particularly preferably 1 to 10 parts by mass, per 100 parts by mass of the total amount of the monomer components. When the content of the polymerization initiator is within the above range, the curability of the composition tends to be improved. The improved curability tends to improve the operability of the molded product, the releasability of the molded product from the mold, and the throughput of molded product production. Two or more types of polymerization initiators may be used in combination.

[0078] <Additives> The curable composition for imprints according to one embodiment of the present invention may further contain an additive. Additives typically used in curable compositions for imprints can be used as appropriate. Examples of additives include polymers, release agents, adhesion promoters, antioxidants, polymerization inhibitors, stabilizers, colorants, plasticizers, surfactants, silane coupling agents, fillers, pigments, dyes, acidic compounds, and sensitizers. When the curable composition for imprints contains an additive, the content thereof is preferably within a range that does not significantly affect the curability of the curable composition for imprints, its ability to fill into a mold, and the properties of the molded product. Specifically, the content of the additive is preferably 0.001 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, and particularly preferably 0.05 to 3 parts by mass, per 100 parts by mass of the total amount of the monomer components.

[0079] In some cases, the additive is a compound having a polymerizable group. In this specification, when such a compound having a polymerizable group corresponds to any one of the components (A) to (C), it is preferable to adjust the blending amount of the compound as a monomer of the corresponding component (A) to (C) rather than as an additive.

[0080] <Solvent> The curable composition for imprints according to one embodiment of the present invention may contain a solvent in addition to the components (A) to (C), the polymerization initiator, and the additives. As the solvent, any solvent typically used in curable compositions for imprints can be used as appropriate. Examples of the solvent include methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, diethylene glycol dimethyl ether, and ethyl lactate. When the curable composition for imprints contains a solvent, the solvent can be used in an amount of 1 to 10,000 parts by mass per 100 parts by mass of the total amount of the components (A) to (C), the polymerization initiator, and the additives.

[0081] <Physical Properties of Composition> The viscosity of the curable composition for imprints according to one embodiment of the present invention is preferably 5,000 mPa·s or less, more preferably 3,000 mPa·s or less, and particularly preferably 1,000 mPa·s or less. There is no particular lower limit to the viscosity, but the viscosity may be, for example, 1 mPa·s or more or 10 mPa·s or more. When the viscosity of the composition falls within the above range, the mold filling property of the composition tends to be improved. Improved filling property tends to result in a molded product in which the concavo-convex pattern of the mold is precisely transferred. When the composition contains components (A) and (B), and, if necessary, other components as described above, within the above ranges, the viscosity of the composition can be controlled within the above range. In this specification, "viscosity" refers to the viscosity at 25°C measured by the method described below.

[0082] <2> Pattern Forming Method One aspect of the present invention is a pattern forming method comprising the steps of: forming a composition layer on a substrate using the curable composition for imprints; bringing the composition layer into contact with a mold having a concave-convex pattern; and curing the composition layer to obtain a molded product having a concave-convex pattern.

[0083] The pattern formation method can be a method that is commonly used for imprint lithography, except that the curable composition for imprints is used as the curable composition.

[0084] The composition layer can be cured by heating or energy ray irradiation. When the composition layer is cured by energy ray irradiation, it is preferable that at least one of the substrate and the mold is substantially transparent to the energy ray. Examples of the energy ray include electromagnetic waves such as infrared rays, visible light, ultraviolet rays, excimer lasers, extreme ultraviolet rays, X-rays, and gamma rays; and particle rays such as electron beams and alpha rays.

[0085] The pattern forming method may further include, before the step of forming the composition layer, a step of subjecting at least one of the substrate and the mold to a release treatment using a release agent or the like. The release agent may be a release agent typically used in imprint lithography, such as a compound having a fluorine atom or a compound having a silicon atom.

[0086] In the above-described pattern forming method, the shape of the concave-convex pattern of the mold used is appropriately selected depending on the intended use of the molded product, etc. The width of the concave-convex pattern is preferably 0.01 to 100 μm, more preferably 0.05 to 50 μm, and even more preferably 0.1 to 30 μm. The height or depth of the concave-convex pattern is preferably 0.01 to 100 μm, more preferably 0.05 to 50 μm, and even more preferably 0.1 to 30 μm. The aspect ratio of the concave-convex pattern is preferably 0.05 to 5.0, and more preferably 0.1 to 3.0. The thickness of the layer (residual film layer) from the bottom of the recesses of the concave-convex pattern to the substrate is preferably 0.005 to 500 μm, more preferably 0.01 to 50 μm, and even more preferably 0.1 to 30 μm. When the thickness of the residual film layer is below a certain level, the crack resistance of the molded product tends to be improved. Furthermore, by setting the aspect ratio of the concave-convex pattern to a certain level or less, it tends to be possible to suppress collapse of the pattern in the molded product.

[0087] In the pattern formation method, the hardness of the molded product can be evaluated by a pencil hardness test and the score calculated by the test. Details will be described later. The pencil hardness of the molded product is preferably 5B or higher, more preferably 3B or higher, and particularly preferably HB or higher. There is no particular upper limit, but for example, 6H or lower is preferred. Furthermore, the hardness score is preferably 2 points or higher, more preferably 4 points or higher, and particularly preferably 7 points or higher. There is no particular upper limit, but for example, 14 points or lower is preferred.

[0088] <3> Component Manufacturing Method One aspect of the present invention is a component manufacturing method in which a component is manufactured using the above-described pattern formation method.

[0089] A method for producing a part according to one embodiment of the present invention can be a method for producing a part using a conventional method for producing a part, except that the curable composition for imprints is used. Specifically, the method for producing a part includes the steps of forming a composition layer on a substrate using the curable composition for imprints, bringing the composition layer into contact with a mold having a concave-convex pattern, and curing the composition layer to obtain a molded product having a concave-convex pattern.

[0090] The method for producing the part can be a method that is usually used for producing parts by imprint lithography, except that the curable composition for imprints is used as the curable composition.

[0091] Some aspects of the present invention will be described below based on examples. The present invention can be implemented according to the intended use.

[0092] <Preparation of Composition Samples> Composition samples (Examples 1 to 30 and Comparative Examples 1 to 10) were prepared by mixing the components at room temperature according to the formulations and blending amounts (parts by mass) shown in Tables 2 and 3 below. The structure and molecular weight of each component are shown below. HPP-A, APG-200, HX-220, and HX-620 were used as component (A). UA-1 to UA-5 were used as component (B). The polymerization initiator in the tables was 2-hydroxy-2-methylpropiophenone (Omnirad 1173, manufactured by IGM Resins B.V.).

[0093]

[0094]

[0095] UA-1 to UA-5 are isomer mixtures derived from the raw material diisocyanate. The synthesis method is shown below. <Synthesis of UA-1> 4.75 g of trimethylhexamethylene diisocyanate (a mixture of 2,2,4- and 2,4,4-isomers), 5.25 g of the acrylate of the following formula HA-1, 2.5 mg of dibutyltin dilaurate, and 5 mg of dibutylhydroxytoluene are added to a 50 mL screw tube bottle and mixed. The mixture is stirred at 80°C for 3 hours to obtain UA-1. <Synthesis of UA-2> UA-2 is obtained by carrying out the same reaction as in the synthesis of UA-1 above, except that 5.88 g of the acrylate of the following formula HA-2 is used instead of 5.25 g of the acrylate of the following formula HA-1. <Synthesis of UA-3> UA-3 is obtained by the same reaction as in the synthesis of UA-1 above, except that 12.22 g of the acrylate of the following formula HA-3 is used instead of 5.25 g of the acrylate of the following formula HA-1. <Synthesis of UA-4> UA-4 is obtained by the same reaction as in the synthesis of UA-1 above, except that 22.8 g of the acrylate of the following formula HA-4 is used instead of 5.25 g of the acrylate of the following formula HA-1. <Synthesis of UA-5> UA-5 is obtained by the same reaction as in the synthesis of UA-1 above, except that 19.0 g of the acrylate of the following formula HA-5 is used instead of 5.25 g of the acrylate of the following formula HA-1.

[0096]

[0097] <Measurement of Viscosity> The viscosity (mPa·s) of each composition sample at 25° C. is measured using an E-type viscometer (HAAKE Viscotester iQ, manufactured by Thermo Fisher Scientific).

[0098] <Evaluation of crack resistance> A composition sample was dropped onto a PET film (Cosmoshine A4100, manufactured by Toyobo Co., Ltd., thickness 100 μm), and a composition layer with a thickness of approximately 15 μm was formed using a bar coater. Next, under a nitrogen atmosphere, the composition was irradiated with a UV-LED lamp (wavelength 365 nm, illuminance 100 mW / cm ２) to expose the composition layer for 10 seconds to obtain a cured product. A two-hole punch (PU-210, manufactured by Plus Corporation) was used to form through-holes with a diameter of approximately 6 mm in areas of the obtained cured product that did not have a concavo-convex pattern, and the appearance of the cured product was evaluated using a laser microscope (OLS-3100, manufactured by Olympus, magnification: 5x). Samples in which cracks due to the formation of through-holes were not observed were marked with "◯", samples in which cracks of 1 mm or less were observed were marked with "△", and samples in which cracks of more than 1 mm were observed were marked with "X". These are shown in the table below.

[0099] <Evaluation of Filling Ability> A composition layer of approximately 24 μm in thickness was formed on a PET film using the same process as in the evaluation of crack resistance. Next, the composition layer was pressed against a nickel mold with a lattice pattern (recess depth 15 μm, line width 15 μm). In this state, the composition layer was visually observed. Samples containing bubbles in the composition layer were marked with "X", and samples not containing bubbles in the composition layer were marked with "O", as shown in the table below.

[0100] <Evaluation of pencil hardness> A composition layer sandwiched between a PET film and a nickel mold was formed by the same process as in the evaluation of the filling property. In this state, the composition layer was irradiated with UV-LED light (wavelength 365 nm, illuminance 100 mW / cm) under a nitrogen atmosphere. ２ ) for 10 seconds to cure the composition layer. After curing, the nickel mold is released to obtain a molded product having a concave-convex pattern. The pencil hardness of the obtained molded product is measured using a method similar to JIS K5600-5-4, and the pencil hardness at which the convex portions of the concave-convex pattern begin to break is determined. Each sample is scored according to the determined hardness in accordance with Table 1 below. A higher score indicates that the concave-convex pattern is less likely to break, and is therefore preferable. When a 6B pencil is used, if not only the convex portions but also the bottoms of the concave portions are scraped, the pencil hardness is recorded as "6B-0" and the score is 0. Furthermore, if only the convex portions are broken but the bottoms of the concave portions are not scraped, the pencil hardness is recorded as "6B" and the score is 1. Note that even if a curable composition for imprints has a low score in this evaluation method, it may be practically usable as a curable composition for imprints of one embodiment of the present invention, provided that it has good filling property and crack resistance.

[0101]

[0102] The composition and blending amount of each composition sample, viscosity (mPa·s), evaluation results of crack resistance, and evaluation results (scores) of pencil hardness are shown in the table below.

[0103]

[0104]

[0105] As shown in Tables 2 and 3, the curable composition for imprints according to one embodiment of the present invention has good filling properties into the concave-convex pattern of the mold and is less susceptible to cracking in the cured product. On the other hand, the other curable compositions are poor in filling properties and in crack resistance of the cured product. ２ is a branched alkylene group, the crack resistance is superior to that of a linear alkylene group. This is presumably because, in the composition of the curable composition for imprints of one embodiment of the present invention, the alkylene group of component (A) has a branched structure, which suppresses molecular rotational motion and imparts to the cured product appropriate mechanical strength with reduced brittleness. Furthermore, it is also found that, among the curable compositions for imprints of one embodiment of the present invention, curable compositions in which the molecular weight of component (A) falls within a specific range not only have excellent crack resistance but also produce molded products with excellent hardness.

[0106] Some aspects of the present invention can provide a curable composition for imprints that can give a molded product that is less susceptible to cracking.

Claims

1. Component (A): a bifunctional (meth)acrylate monomer, Component (B): a bifunctional urethane (meth)acrylate monomer, The content ratio of the component (A) to the component (B) is 20 to 80:80 to 20 by mass ratio, The component (A) is represented by the following general formula (1): 【Chemistry 1】 General formula (1) (In the general formula (1), R １ each independently represents a hydrogen atom or a methyl group; R ２ represents a branched alkylene group having 3 to 50 carbon atoms which may have a substituent; At least one methylene group contained in the branched alkylene group is selected from the group consisting of -O-, -CO-, -S-, -SO-, and -SO ２ -, -NH- and -NR Ｎ１ -, and R Ｎ１ represents a monovalent group selected from the group consisting of a linear alkyl group having 1 to 10 carbon atoms, a branched alkyl group having 3 to 10 carbon atoms, a cyclic alkyl group having 3 to 10 carbon atoms, and an aryl group having 6 to 10 carbon atoms. The component (B) is represented by the following general formula (2): 【Chemistry 2】 General formula (2) (In the general formula (2), R ３ each independently represents a hydrogen atom or a methyl group; R ４ each independently represents a linear alkylene group having 2 to 30 carbon atoms which may have a substituent, or a branched alkylene group having 3 to 30 carbon atoms which may have a substituent; At least one methylene group contained in the linear or branched alkylene group is selected from the group consisting of -O-, -CO-, -S-, -SO-, and -SO ２ -, -NH- and -NR Ｎ２ -, and R Ｎ２ represents a monovalent group selected from the group consisting of a linear alkyl group having 1 to 10 carbon atoms, a branched alkyl group having 3 to 10 carbon atoms, a cyclic alkyl group having 3 to 10 carbon atoms, and an aryl group having 6 to 10 carbon atoms; Each Z independently represents -O-CO-NH- or -NH-CO-O-; R ５ represents a divalent group selected from the group consisting of a linear alkylene group having 2 to 50 carbon atoms, which may have a substituent, a branched alkylene group having 3 to 50 carbon atoms, which may have a substituent, and a cyclic alkylene group having 3 to 50 carbon atoms, which may have a substituent.

2. A curable composition for imprints as described in claim 1, having a viscosity of 5000 mPa·s or less.

3. Optionally containing an additive, 3. The curable composition for imprints according to claim 1, wherein a content of the additive is 0 to 3 parts by mass or less per 100 parts by mass of the total amount of the monomer components.

4. The curable composition for imprints according to any one of claims 1 to 3, wherein the component (A) is represented by at least one selected from the group consisting of the following general formulas (1-1), (1-2), and (1-3): 【Chemistry 3】 (General formula 1-1) (In the general formula (1-1), R １ is R in general formula (1). １ represents a group selected from the same options as R ６ represents a branched alkylene group having 3 to 20 carbon atoms which may have a substituent, and a methylene group contained in the branched alkylene group is not substituted with a heteroatom-containing group. 【Chemistry 4】 (General formula 1-2) (In the general formula (1-2), R １ is R in general formula (1). １ represents a group selected from the same options as R ７ each independently represents a linear alkylene group having 2 to 10 carbon atoms which may have a substituent, or a branched alkylene group having 3 to 10 carbon atoms which may have a substituent; R ８ represents a linear alkylene group having 2 to 10 carbon atoms which may have a substituent or a branched alkylene group having 3 to 10 carbon atoms which may have a substituent; R ７ and R ８ At least one of the groups is a branched alkylene group; n １２ Each of n represents an integer from 0 to 10, provided that １２ At least one of the is an integer of 1 or more.) 【Chemistry 5】 (General formula 1-3) (In the general formula (1-3), R １ is R in general formula (1). １ represents a group selected from the same options as R ９ each independently represents a linear alkylene group having 2 to 10 carbon atoms which may have a substituent, or a branched alkylene group having 3 to 10 carbon atoms which may have a substituent, provided that at least one of R ９ is a branched alkylene group; n １３ represents an integer from 1 to 20.

5. The curable composition for imprints according to any one of claims 1 to 4, wherein the molecular weight of the component (A) is 800 or less.

6. The curable composition for imprints according to any one of claims 1 to 5, wherein the molecular weight of the component (B) is 1,500 or less.

7. A step of forming a composition layer on a substrate using the curable composition for imprints according to any one of claims 1 to 6; contacting the composition layer with a mold having a relief pattern; A step of curing the composition layer to obtain a molded product having a concave-convex pattern; The pattern forming method includes the steps of:

8. A method for manufacturing a component, using the pattern formation method according to claim 7.

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