Polymers, varnishes and adhesive compositions

Abstract

To provide a polymer having excellent curability and also excellent thermostability, and an adhesive composition comprising the polymer, which can provide a cured product having resistance to coloration under a use environment.SOLUTION: A polymer comprises constitutional units represented by the following general formulae (1)-(3).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to polymer, varnish and adhesive compositions. [Background technology]

[0002] Conventionally, adhesive compositions have been used in LED encapsulants, optical adhesives, and optical devices to bond to protective glass or the like to protect device parts from foreign matter such as moisture and dust. These adhesive compositions are required to be transparent adhesives that have excellent heat resistance and suppress discoloration, as well as adhesive strength with silicon substrates, glass substrates, etc.

[0003] Patent Document 1 discloses an optical permanent adhesive composition containing a heat- or light-curable resin containing a structural unit derived from a specific bifunctional (meth)acrylic acid ester, (B) a polymerizable monomer, and (C) an antioxidant. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-115064 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the adhesive composition described in Patent Document 1 has low heat resistance and tends to become discolored under the environment in which it is used. [Means for solving the problem]

[0006] The present inventors have found that the above problems can be solved by using a polymer having a predetermined structure, and have completed the present invention. That is, the present invention can be shown as follows.

[0007] According to the present invention, it is possible to provide a polymer containing constitutional units represented by the following general formulas (1) to (3). [ka] (In general formula (1), R 1 , R 2 , R 3 and R 4 are each independently a hydrogen atom or an organic group having 1 to 30 carbon atoms; a1 is 0, 1 or 2. In general formula (3), Q 1 represents an alkyl group having 1 to 10 carbon atoms.

[0008] According to the present invention, A varnish containing the polymer and an organic solvent can be provided.

[0009] According to the present invention, An adhesive composition can be provided that includes the polymer. [Effects of the Invention]

[0010] The polymer of the present invention has excellent curability and heat resistance, and therefore an adhesive composition containing the polymer can provide a transparent cured product (adhesive) that is inhibited from discoloring under the usage environment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described. In this specification, the expression "a to b" in the description of a numerical range means not less than a and not more than b, unless otherwise specified. For example, "5 to 90%" means "not less than 5% and not more than 90%." In this specification, the term "(meth)acrylic" represents a concept that encompasses both acrylic and methacrylic. The same applies to similar terms such as "(meth)acrylate."

[0012] [polymer] The polymer of this embodiment contains structural units (1) to (3) represented by the following general formulas (1) to (3): The polymer of this embodiment is heat-curable or photo-curable and therefore has excellent curability and heat resistance, and therefore an adhesive composition containing this polymer can provide a transparent cured product (adhesive) that is suppressed from discoloring under the usage environment.

[0013] [ka]

[0014] In the structural unit (1) represented by the general formula (1), R 1 , R 2 , R 3 and R 4 are each independently a hydrogen atom or an organic group having 1 to 30 carbon atoms; a1 is 0, 1 or 2.

[0015] The structural unit (1) represented by general formula (1) is chemically robust. Therefore, polymers containing this structural unit undergo little weight loss when subjected to heat treatment and are stable. Therefore, adhesive compositions containing the polymer can be suitably used in optical adhesive compositions that require heat resistance.

[0016] R 1 ~R 4 Examples of the organic group having 1 to 30 carbon atoms that can constitute the above group include substituted or unsubstituted, straight-chain or branched-chain alkyl groups having 1 to 30 carbon atoms, and more specific examples include alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkaryl groups, cycloalkyl groups, alkoxy groups, heterocyclic groups, and carboxyl groups.

[0017] Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. Examples of the alkenyl group include an allyl group, a pentenyl group, and a vinyl group. The alkynyl group includes, for example, an ethynyl group. Examples of the alkylidene group include a methylidene group and an ethylidene group. Examples of the aryl group include a tolyl group, a xylyl group, a phenyl group, a naphthyl group, and an anthracenyl group. Examples of the aralkyl group include a benzyl group and a phenethyl group. Examples of the alkaryl group include a tolyl group and a xylyl group. Examples of the cycloalkyl group include an adamantyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group.

[0018] Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, an isobutoxy group, a tert-butoxy group, an n-pentyloxy group, a neopentyloxy group, and an n-hexyloxy group. Examples of the heterocyclic group include an epoxy group and an oxetanyl group. In the structural unit represented by general formula (1), R 1 , R 2 , R 3 and R 4 is preferably hydrogen or an alkyl group, more preferably hydrogen.

[0019] In addition, R 1 , R 2 , R 3 and R 4 The hydrogen atoms in the organic group having 1 to 30 carbon atoms may be substituted with any atomic group. For example, they may be substituted with a fluorine atom, a hydroxyl group, a carboxyl group, etc. More specifically, R 1 , R 2 , R 3 and R 4 As the organic group having 1 to 30 carbon atoms, a fluorinated alkyl group or the like may be selected.

[0020] In the constitutional unit represented by general formula (1), a1 is preferably 0 or 1, and more preferably 0.

[0021] In general formula (3), Q 1 represents an alkyl group having 1 to 10 carbon atoms, preferably an alkyl group having 2 to 8 carbon atoms, and more preferably an alkyl group having 3 to 6 carbon atoms.

[0022] Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group.

[0023] From the viewpoint of the effects of the present invention, the polymer of this embodiment preferably contains, of all structural units, 30 to 50 mol % of the structural unit (1), 0 to 40 mol % of the structural unit (2), and 10 to 50 mol % of the structural unit (3), It is more preferable that the structural unit (1) is 40 to 50 mol %, the structural unit (2) is 0 to 20 mol %, and the structural unit (3) is 30 to 50 mol %.

[0024] The content (ratio) of each structural unit contained in the polymer can be determined by the amount (molar amount) of raw materials used in synthesizing the polymer, the amount of raw materials remaining after synthesis, and various spectra (e.g., IR spectrum, 1 H-NMR spectrum, 13 It can be estimated / calculated from the presence and area of ​​peaks in the C-NMR spectrum.

[0025] In this embodiment, the polymer may further include a structural unit (4) represented by the following general formula (4).

[0026] [ka]

[0027] In general formula (4), Q 2 represents a group containing one or more (meth)acryloyl groups, a hydrogen atom, or a substituted or unsubstituted alkyl group having 2 to 10 carbon atoms, which may contain an oxygen atom. The alkyl group having 2 to 10 carbon atoms is represented by Q in general formula (3). 1 It has the same meaning as the alkyl group having 2 to 10 carbon atoms and may contain an oxygen atom at any position. An alkyl group containing an oxygen atom means that an oxygen atom (—O—) is introduced into the carbon chain of the alkyl group. The alkyl group having 2 to 10 carbon atoms and optionally containing an oxygen atom may be substituted with any substituent, such as a hydroxyl group, an alkyl group, an aryl group, an alkoxy group, or an aryloxy group.

[0028] Q 2 In the formula, the group containing one or more (meth)acryloyl groups is preferably a group containing 1 to 6 (meth)acryloyl groups, more preferably a group containing 1 to 5 (meth)acryloyl groups, and even more preferably a group containing 1 to 3 (meth)acryloyl groups. 2 By optimizing the number of (meth)acryloyl groups contained in the compound, it is possible to obtain a cured product that has excellent heat resistance, is inhibited from yellowing, and is excellent in transparency.

[0029] The proportion of the structural units represented by general formula (4) in all structural units contained in the polymer of this embodiment is preferably 10 to 50 mol %, more preferably 30 to 50 mol %. The structural unit (3) is preferably 10 to 50 mol %.

[0030] Q 2 In the above formula, the group containing one or more (meth)acryloyl groups is preferably, for example, a group represented by the following general formula (4a).

[0031] [ka]

[0032] In general formula (4a), X10 is a divalent organic group, and R is a hydrogen atom or a methyl group. X 10 The total number of carbon atoms is preferably 1 to 30, more preferably 1 to 20, and even more preferably 1 to 10. In general formula (4a), X 10 is a divalent organic group, and R is a hydrogen atom or a methyl group. X 10 The total number of carbon atoms is preferably 1 to 30, more preferably 1 to 20, and even more preferably 1 to 10.

[0033] X 10 The divalent organic group is preferably, for example, an alkylene group. Some of the -CH2- in this alkylene group may be ether groups (-O-). The alkylene group may be linear or branched, but is more preferably linear.

[0034] X 10 The divalent organic group X is more preferably a linear alkylene group having a total of 3 to 6 carbon atoms. 10 The number of carbon atoms (X 10 By appropriately selecting the chain length of the structural unit represented by general formula (4), the structural unit represented by general formula (4) can be more easily involved in the crosslinking reaction, thereby increasing sensitivity and providing a cured product with excellent durability, such as solvent resistance.

[0035] X 10 The divalent organic group (for example, an alkylene group) may be substituted with any substituent, such as a hydroxyl group, an alkyl group, an aryl group, an alkoxy group, or an aryloxy group.

[0036] Also, X 10 The divalent organic group may be any group other than an alkylene group, such as a divalent group formed by linking one or more groups selected from alkylene groups, cycloalkylene groups, arylene groups, ether groups, carbonyl groups, carboxy groups, and the like.

[0037] The polymer of the present embodiment can contain, in addition to the structural unit (1) and the structural unit (2), a structural unit (5) represented by the following general formula (5) which is composed of a structural unit (3) represented by general formula (3) and a structural unit (4) represented by general formula (4).

[0038] [ka]

[0039] In general formula (5), Q 1 is Q in general formula (3) 1 is synonymous with Q 2 is Q in general formula (4) 2 is synonymous with.

[0040] In this embodiment, the polymer contains Q 1 is an alkyl group having 1 to 10 carbon atoms, and Q 2 Preferably, the adhesive composition further comprises a structural unit in which the alkyl group is a substituted or unsubstituted alkyl group having 2 to 10 carbon atoms, which may contain an oxygen atom. This imparts flexibility to the polymer structure, and the cured film (adhesive layer) formed from the adhesive composition containing the polymer can be formed into a thick film, exhibiting excellent chemical resistance and insulating properties. Furthermore, by adjusting the crosslinkable group in the molecular structure, warpage and the like can be alleviated after curing, resulting in excellent product reliability. Furthermore, carboxylic acids (Q 2 By adjusting the amount of structural units in which Q is a hydrogen atom, the alkali resistance and chemical resistance of the resulting cured film can be improved. 2 By increasing the amount of structural units where (is a hydrogen atom), it can be used for flexible optical adhesives while retaining alkali-soluble resist properties. Furthermore, by introducing a large amount of alkyl side chains into the molecule, it is possible to introduce crosslinkable groups, giving it a high degree of freedom, and by crosslinking it can form the same cured product with other compounds without becoming a mixture.

[0041] The proportion of the structural units represented by general formula (5) in all structural units contained in the polymer of this embodiment is preferably 0 to 50 mol %, more preferably 30 to 50 mol %.

[0042] The polymer of this embodiment may further contain other divalent structural units derived from a copolymerizable compound having a double bond.

[0043] The structural units include, for example, at least one structural unit derived from substituted or unsubstituted indene, maleimide, styrene, acenaphthylene, norbornadiene, dihydrofuran, terpene compounds (e.g., pinene, limonene, etc.), linear alkenes (e.g., pentene, etc.), cyclic alkenes (cyclohexene, etc.), cyclododecatriene, tricycloundecene, dialkyl fumarates (e.g., dimethyl fumarate, ethyl fumarate, dibutyl fumarate, etc.), coumarin, (meth)acrylic acid compounds (e.g., methyl methacrylate, methyl acrylate), vinyl acetate, vinyl ethers (e.g., 2-hydroxyethyl vinyl ether, etc.), etc.

[0044] Substituents that these monomers may have include alkyl groups, aryl groups, etc. More specifically, substituted indenes include methylindene, etc. Substituted maleimides include cyclohexylmaleimide and phenylmaleimide, etc. Substituted styrenes include methylstyrene and vinyltoluene, etc.

[0045] Among these, preferred are structural units represented by general formula (a) (divalent structural units derived from substituted or unsubstituted indene), structural units represented by general formula (b) (divalent structural units derived from substituted or unsubstituted maleimide), structural units represented by general formula (c) (divalent structural units derived from substituted or unsubstituted styrene), or structural units represented by general formula (9) (divalent structural units derived from substituted or unsubstituted norbornadiene).

[0046] [ka]

[0047] In general formula (a), R 1 and R 2 each independently represents a hydrogen atom, an alkyl group, or an aryl group. 3 represents a hydrogen atom, an alkyl group, or an aryl group. 4 ~R 6 are each independently a hydrogen atom, an alkyl group, or an aryl group. 7 ~R 10 each independently represents a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms.

[0048] From the viewpoint of the effects of the present invention, the polymer of the present embodiment may be bonded to a monofunctional thiol group-containing compound such as butanethiol or dodecanethiol via a thioether group derived from the thiol group of the compound, or may be bonded to a difunctional or higher functional thiol group-containing compound via a thioether group derived from at least one thiol group.

[0049] Specifically, the polymer has a structure in which at least one polymer chain represented by Chain below is bonded to a monovalent to hexavalent organic group having 1 to 30 carbon atoms, which is derived from a monofunctional or more thiol group-containing compound. Specifically, the polymer of this embodiment can be represented by the following general formula (P).

[0050] [ka]

[0051] In general formula (P), Chain is the polymer chain containing the above-mentioned structural units. In the general formula (P), Y is a monovalent to hexavalent organic group (i) having 1 to 30 carbon atoms and derived from a monofunctional or higher thiol group-containing compound.

[0052] In this embodiment, the number of functional groups is the number of thiol groups. That is, the thiol group-containing compound contains one or more thiol groups, and the organic group (i) is bonded to Chain via 1 to 6 thioether groups derived from the thiol groups. The organic group (i) may have a thiol group that is not involved in bonding with Chain, and the polymer can be obtained as a mixture of resins each having a number n (number of bonds) of 1 to 6. The organic group (i) having 1 to 30 carbon atoms is monofunctional or more, preferably difunctional or more, more preferably trifunctional or more. There is no particular upper limit, but it is hexafunctional or less. The valence of the organic group (i) having 1 to 30 carbon atoms is, from the viewpoint of the effects of the present invention, monovalent to hexavalent, preferably divalent to hexavalent, and more preferably trivalent to hexavalent.

[0053] The monovalent to hexavalent organic group (i) having 1 to 30 carbon atoms may contain one or more atoms selected from O, N, S, P, and Si. Examples of the monovalent to hexavalent organic group (i) having 1 to 30 carbon atoms include alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkaryl groups, cycloalkyl groups, alkoxy groups, and heterocyclic groups each having 1 to 6 thioether groups (-S-* (* represents a bond)).

[0054] Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, and decyl groups. Examples of alkenyl groups include allyl, pentenyl, and vinyl groups. Alkynyl groups include ethynyl groups.

[0055] Examples of the alkylidene group include a methylidene group and an ethylidene group. Examples of the aryl group include a tolyl group, a xylyl group, a phenyl group, a naphthyl group, and an anthracenyl group. Examples of the aralkyl group include a benzyl group and a phenethyl group. Examples of the alkaryl group include a tolyl group and a xylyl group. Examples of cycloalkyl groups include adamantyl, cyclopentyl, cyclohexyl, and cyclooctyl groups.

[0056] Examples of alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, s-butoxy, isobutoxy, t-butoxy, n-pentyloxy, neopentyloxy, and n-hexyloxy groups. Examples of the heterocyclic group include an epoxy group and an oxetanyl group. Examples of the bifunctional or higher functional thiol group-containing compound include compounds represented by the following chemical formulas (s-1) to (s-20).

[0057] [ka]

[0058] [ka]

[0059] [ka]

[0060] [ka]

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[0075] [ka]

[0076] [ka]

[0077] The bifunctional or higher functional thiol group-containing compound may be used alone or in combination of two or more.

[0078] The monovalent to hexavalent organic group (i) having 1 to 30 carbon atoms has a thioether group (-S-* (* is a bond)) derived from the thiol group of the thiol group-containing compound at its terminal, and bonds to a structural unit contained in Chain via the thioether group. The organic group (i) may have a thiol group that is not involved in bonding to Chain.

[0079] In general formula (P), a structure other than Chain may be bonded to Y. Specifically, general formula (P) can be represented by the following general formula (P').

[0080] [ka]

[0081] In general formula (P'), Chain and Y have the same meanings as in general formula (P), p is an integer of 1 or more, q is an integer of 0 or more, and p+q is 1-6.

[0082] Q, which is a structure other than Chain, is not particularly limited as long as it can be bonded to Y, and can include various components used in synthesis reactions, for example, at least one selected from the structural unit represented by the general formula (1), the structural unit represented by the general formula (2), the structural unit represented by the general formula (3), the structural unit represented by the general formula (4), the structural unit represented by the general formula (5), the structural unit represented by the general formula (6), and a divalent structural unit derived from a copolymerizable compound having a double bond, and a group derived from the difunctional or higher thiol group-containing compound.

[0083] When a compound represented by the chemical formula (s-2) is used as the bifunctional or higher thiol group-containing compound, the polymer of this embodiment can have, for example, a structure represented by the following general formula (I).

[0084] [ka]

[0085] In general formula (I), Chain has the same meaning as in general formula (P1), and the structures of the four Chains may be the same or different.

[0086] In the general formula (I), an example is shown in which the compound represented by chemical formula (s-2) is bonded to four Chains via thioether groups derived from four mercapto groups, but a structure in which 1 to 3 Chains are bonded may also be used. The remaining thioether group may be bonded to the aforementioned Q. In this embodiment, the polymer can be obtained as a mixture containing at least one compound in which 1 to 4 Chains are bonded.

[0087] The weight-average molecular weight Mw of the polymer is, for example, 1,000 to 15,000, preferably 1,500 to 12,000, more preferably 2,000 to 10,000, and even more preferably 3,000 to 8,000. By appropriately adjusting the weight-average molecular weight, it is possible to adjust the viscosity of the polymer when it is made into a solution, the sensitivity, and the solubility in an alkaline developer.

[0088] The dispersity of the polymer (weight average molecular weight Mw / number average molecular weight Mn) is preferably 1.0 to 5.0, more preferably 1.0 to 4.0, and even more preferably 1.0 to 3.0. By appropriately adjusting the dispersity, the physical properties of the polymer can be made uniform, which is preferable. These values ​​can be determined by gel permeation chromatography (GPC) measurement using polystyrene as a standard substance.

[0089] The glass transition temperature of the polymer is preferably 150 to 250°C, more preferably 170 to 230°C. The polymer has a relatively high glass transition temperature due to the inclusion of a structural unit represented by general formula (1). This is preferable in that a pattern formed on a substrate can be stable when producing a liquid crystal display device or a solid-state imaging device. The glass transition temperature can be determined, for example, by differential thermal analysis (DTA).

[0090] The polymer of the present embodiment has excellent solubility in various organic solvents, and therefore the types and amounts of additives in varnishes and adhesive compositions can be adjusted as desired, providing excellent freedom in formulation design.

[0091] Examples of organic solvents include acetone, methyl ethyl ketone, toluene, propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), ethyl acetate, butyl acetate, cyclohexanone, methyl amyl ketone, ethyl isobutyl ether, butyl acetate, chloroform, n-propyl alcohol, ethylene glycol, and diethylene glycol.

[0092] <Polymer manufacturing method> The method for producing the polymer of this embodiment will be described using the method for producing the polymer represented by the general formula (P) as an example.

[0093] The polymer can be produced (synthesized) by any method. Step (I): preparing a raw material polymer containing a structural unit represented by general formula (1), a structural unit represented by general formula (2), and the monovalent to hexavalent organic group (i) having 1 to 30 carbon atoms; Step (II): The raw polymer obtained in step (I) and Q 1 Alcohols represented by -OH (where Q 1 has the same meaning as above) to open the maleic anhydride moiety of the structural unit represented by the general formula (2) and generate the structural unit of the general formula (3) and a carboxyl group in the raw polymer, thereby preparing a polymer precursor; Step (III): A step of reacting the polymer precursor obtained in Step (II) with an epoxy group-containing (meth)acrylic compound in the presence of a catalyst to prepare a polymer containing a structural unit represented by general formula (1), a structural unit represented by general formula (2), a structural unit represented by general formula (3), a structural unit represented by general formula (4), and the monovalent to hexavalent organic group (i) having 1 to 30 carbon atoms; It can be produced by

[0094] In the step (II), when both a polyfunctional (meth)acrylic monomer and a monofunctional (meth)acrylic monomer are used, it is preferable to first react the polyfunctional (meth)acrylic monomer with the raw material polymer, and then react the monofunctional (meth)acrylic monomer with the resulting reaction mixture.

[0095] (Process (I)) In step (I), the step of preparing a raw material polymer containing a structural unit represented by general formula (1), a structural unit represented by general formula (2), and the organic group (i) having 1 to 30 carbon atoms and a valence of 1 to 6 can be carried out by polymerizing (addition polymerizing) a monomer composition containing a monomer represented by general formula (1') and maleic anhydride in the presence of the thiol group-containing compound having two or more functionalities. 1 , R 2 , R 3 and R 4 The definition of a1 is the same as that in general formula (1), and the same applies to preferred embodiments.

[0096] [ka]

[0097] Examples of the monomer represented by general formula (1') include norbornene, bicyclo[2.2.1]-hept-2-ene (trivial name: 2-norbornene), 5-methyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene, 5-hexyl-2-norbornene, 5-decyl-2-norbornene, 5-allyl-2-norbornene, 5-(2-propenyl)-2-norbornene, 5-(1-methyl-4-pentenyl)-2-norbornene, 5-ethynyl-2-norbornene, 5-benzyl-2-norbornene, 5-phenethyl-2-norbornene, 2-acetyl-5-norbornene, methyl 5-norbornene-2-carboxylate, and 5-norbornene-2,3-dicarboxylic anhydride. In the polymerization, the monomer represented by the general formula (1') may be used alone or in combination of two or more kinds. The monomer composition may contain other monomers in addition to the above monomers.

[0098] The other monomer is not particularly limited as long as it is a copolymerizable compound having a double bond, and known compounds can be used. These can be polymerized with the monomer represented by general formula (1') and maleic anhydride. Examples of the other monomer include substituted or unsubstituted indene, maleimide, styrene, acenaphthylene, norbornadiene, dihydrofuran, terpene compounds (e.g., pinene, limonene, etc.), linear alkenes (e.g., pentene, etc.), cyclic alkenes (e.g., cyclohexene, etc.), cyclododecatriene, tricycloundecene, dialkyl fumarates (e.g., dimethyl fumarate, ethyl fumarate, dibutyl fumarate, etc.), coumarin, (meth)acrylic acid compounds (e.g., methyl methacrylate, methyl acrylate), vinyl acetate, and vinyl ethers (e.g., 2-hydroxyethyl vinyl ether, etc.). In step (I), the monomer represented by general formula (1'), maleic anhydride, and, if necessary, other monomers can be polymerized (addition polymerized) in the presence of the bifunctional or higher thiol group-containing compound.

[0099] Examples of bifunctional or higher functional thiol group-containing compounds include, but are not limited to, the compounds represented by the above chemical formulas (s-1) to (s-20). The bifunctional or higher functional thiol group-containing compounds may be used singly or in combination of two or more.

[0100] Although there is no limitation on the polymerization method, radical polymerization using a radical polymerization initiator is preferred. Examples of the polymerization initiator that can be used include azo compounds and organic peroxides.

[0101] Specific examples of the azo compound include azobisisobutyronitrile (AIBN), dimethyl 2,2'-azobis(2-methylpropionate), and 1,1'-azobis(cyclohexanecarbonitrile) (ABCN).

[0102] Examples of organic peroxides include hydrogen peroxide, di-tert-butyl peroxide (DTBP), benzoyl peroxide (benzoyl peroxide, BPO), and methyl ethyl ketone peroxide (MEKP). The polymerization initiator may be used alone or in combination of two or more.

[0103] The solvent used in the polymerization reaction may be, for example, an organic solvent such as diethyl ether, tetrahydrofuran, toluene, methyl ethyl ketone, etc. The polymerization solvent may be a single solvent or a mixed solvent.

[0104] The raw polymer is synthesized by dissolving the monomer represented by general formula (1'), maleic anhydride, and a polymerization initiator in a solvent and charging the resulting solution into a reaction vessel, then heating the mixture and adding the bifunctional or higher thiol group-containing compound dropwise to cause addition polymerization. The heating temperature is, for example, 50 to 80°C, and the heating time is, for example, 5 to 20 hours.

[0105] When charging into a reaction vessel, the molar ratio of the monomer represented by general formula (1') to maleic anhydride is preferably 0.5:1 to 1:0.5. From the viewpoint of molecular structure control, the molar ratio is preferably 1:1. Through such a process, a "raw polymer" can be obtained.

[0106] The raw polymer may be a random copolymer, an alternating copolymer, a block copolymer, or a periodic copolymer. Typically, it is a random copolymer or an alternating copolymer. Maleic anhydride is generally known as a monomer with strong alternating copolymerizability. After synthesis of the raw polymer, a step of removing low molecular weight components such as unreacted monomers, oligomers, and residual polymerization initiators may be carried out.

[0107] Specifically, the organic layer containing the synthesized raw polymer and low-molecular-weight components is concentrated and then mixed with an organic solvent such as methyl ethyl ketone (MEK) to obtain a solution. This solution is then mixed with a poor solvent such as methanol to precipitate the monomer. The precipitate is filtered and dried, thereby increasing the purity of the raw polymer.

[0108] (Step (II)) The raw polymer obtained in step (I) and Q 1 Alcohols represented by -OH (where Q 1 has the same meaning as above) to open the maleic anhydride moiety of the structural unit represented by the general formula (2) above, thereby generating the structural unit of the general formula (3) and a carboxyl group in the raw polymer, thereby obtaining a polymer precursor.

[0109] Q 1 Examples of alcohols represented by -OH include methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, pentanol, hexanol, octanol, and decanol, and any one or more of these can be used.

[0110] The solvent for dissolving the raw material polymer can be appropriately selected from those that do not inhibit the reaction, and the heating conditions can be set, for example, in the range of 50 to 120° C. The reaction time can be appropriately set while observing the degree of change in the chemical structure of the polymer, etc.

[0111] The solvent used in this step may be, for example, a highly versatile solvent such as diethyl ether, tetrahydrofuran, toluene, methyl ethyl ketone, or ethyl acetate, and any one or more of these may be used. Also, use Q 1 -OH plays the role of a solvent, Q 1 The reaction may be carried out without adding any solvent other than -OH.

[0112] During this heating, the reaction will proceed even without a catalyst, but in order to further promote the reaction, a catalyst may be added as appropriate, for example, a base catalyst or an acid catalyst.

[0113] Examples of base catalysts that can be used include alkylamines such as pyridine and triethylamine, amine compounds such as dimethylaniline, urotropine, and dimethylaminopyridine, and metal salts such as sodium acetate. At least one of these can be used.

[0114] The acid catalyst may be a mineral acid such as sulfuric acid or hydrochloric acid, an organic acid such as paratoluenesulfonic acid, or a Lewis acid such as boron trifluoride etherate, and any one or more of these may be used.

[0115] (Process (III)) The polymer precursor obtained in step (II) is reacted with an epoxy group-containing (meth)acrylic compound in the presence of a catalyst, and the carboxyl group of the polymer precursor reacts with the epoxy group of the epoxy group-containing (meth)acrylic compound to form a structural unit represented by general formula (4). This produces a polymer containing a structural unit represented by general formula (1), a structural unit represented by general formula (2), a structural unit represented by general formula (3), a structural unit represented by general formula (4), and the monovalent to hexavalent organic group (i) having 1 to 30 carbon atoms.

[0116] The step (III) is preferably carried out by adding an epoxy group-containing (meth)acrylic compound to the reaction system containing the polymer precursor obtained in the step (II).

[0117] The reaction between the polymer precursor and the epoxy group-containing (meth)acrylic compound proceeds in the presence of a basic catalyst. The basic catalyst remaining in the reaction system obtained in step (II) can be used as is. Therefore, step (III) is preferably carried out in situ by adding the epoxy group-containing (meth)acrylic compound to the reaction mixture containing the polymer precursor obtained in step (II), without isolating and purifying the polymer precursor from the reaction mixture containing the polymer precursor obtained in step (II) or neutralizing the basic catalyst contained in the mixture.

[0118] Specifically, an epoxy group-containing (meth)acrylic compound is added to a reaction mixture containing a polymer precursor, and the resulting reaction solution is heated preferably at 60 to 100°C for about 1 to 24 hours. This causes a reaction between the carboxyl group of the polymer precursor and the epoxy group of the epoxy group-containing (meth)acrylic compound to form a structural unit represented by general formula (4), thereby producing a polymer.

[0119] Examples of epoxy group-containing (meth)acrylic compounds include glycidyl methacrylate (GMA), 4-hydroxybutyl acrylate glycidyl ether (4HBAGE), 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxycyclohexylmethyl methacrylate, and glycidyl acrylate, and one or more selected from these can be used.

[0120] The amount of the epoxy group-containing (meth)acrylic compound added is preferably 0.1 to 3.0 moles per mole of the carboxyl group of the polymer precursor.

[0121] In this step, it is preferable to react an alkyl glycidyl ether compound with the epoxy group-containing (meth)acrylic compound. By reacting the alkyl glycidyl ether compound, the balance between the amount of crosslinkable groups ((meth)acrylic groups) and the amount of carboxyl groups can be adjusted, and chemical resistance and flexibility can be improved.

[0122] Examples of alkyl glycidyl ether compounds include butyl glycidyl ether, pentyl glycidyl ether, hexyl glycidyl ether, cyclohexyl glycidyl ether, heptyl glycidyl ether, octyl glycidyl ether, ethylhexyl glycidyl ether, nonyl glycidyl ether, decyl glycidyl ether, undecyl glycidyl ether, and dodecyl glycidyl ether.

[0123] The total amount of the epoxy group-containing (meth)acrylic compound and the alkyl glycidyl ether compound added is preferably 0.1 to 3.0 moles per mole of carboxyl group in the polymer precursor. The molar ratio (a:b) of the epoxy group-containing (meth)acrylic compound (a) to the alkyl glycidyl ether compound (b) is 100:1 to 1:100. After the step (III), it is preferable to further carry out the following steps as appropriate in order to remove unnecessary components other than the desired polymer.

[0124] First, the reaction mixture is neutralized by adding an acid (for example, formic acid, citric acid, etc.), and the reaction mixture is reprecipitated in water as a poor solvent, and the water is removed to obtain a viscous polymer.

[0125] The resulting polymer is washed with water to remove impurities. If impurities cannot be removed with water alone, washing may be performed by mixing with an organic solvent such as acetone. The water used here is preferably ion-exchanged water.

[0126] After washing with ion-exchanged water, an organic solvent such as PGMEA is added to the polymer, and the mixture is heated under vacuum to remove impurities, thereby obtaining a highly pure polymer solution of the present embodiment.

[0127] [varnish] The varnish of this embodiment contains the above-mentioned polymer and an organic solvent. The polymer of the present embodiment has excellent solubility in various organic solvents, and therefore the solid content can be increased to, for example, 50 parts by weight or more, preferably 70 parts by weight or more, per 100 parts by mass of the organic solvent. The high polymer concentration results in excellent workability and the like.

[0128] Examples of the organic solvent include acetone, methyl ethyl ketone, toluene, propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), ethyl acetate, butyl acetate, cyclohexanone, and methyl amino ketone.

[0129] [Adhesive composition] The adhesive composition of the present embodiment contains the above-described polymer. From the viewpoint of the effects of the present invention, the polymer of this embodiment can be contained in an amount of preferably 10% by mass or more and 98% by mass or less, and more preferably 60% by mass or more and 95% by mass or less, relative to 100% by mass of the adhesive composition.

[0130] The adhesive composition of the present embodiment may contain a polymerization initiator, a photoacid generator, a photobase generator, a thermal acid generator, a thermal base generator, an antioxidant, a surfactant, a dispersant, an ultraviolet absorber, an ultraviolet blocking agent, an infrared blocking agent, or the like.

[0131] The adhesive composition of this embodiment is heated at 230° C. for 60 minutes to obtain a cured film having a thickness of 3 μm, which has a transmittance of 97% or more, and preferably 98% or more, for light having a wavelength of 550 nm. The cured product obtained from the adhesive composition of this embodiment has excellent transparency. From this perspective, the transmittance of the cured film to light with a wavelength of 400 nm is 95% or more, and preferably 98% or more. Furthermore, the cured product obtained from the adhesive composition of this embodiment has excellent heat resistance and is inhibited from discoloring, and therefore has excellent transparency.

[0132] The cured product obtained from the adhesive composition of this embodiment has excellent adhesion, and further has excellent heat resistance and discoloration suppression effects, and therefore can be suitably used as an adhesive in semiconductor and other usage environments.

[0133] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted as long as they do not impair the effects of the present invention. [Example]

[0134] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0135] The compounds used in the examples may be indicated by the following abbreviations or trade names. MAN: Maleic anhydride NB: 2-Norbornene PEMP: Pentaerythritol tetrakis(3-mercaptopropionate) GMA: Glycidyl methacrylate BGE: Butyl glycidyl ether HEMA: 2-hydroxyethyl methacrylate

[0136] <Synthesis of precursor polymer> [Synthesis Example 1] (Synthesis of Precursor Polymer A) A reaction vessel equipped with a stirrer, condenser, and dropping funnel was charged with 602.56 g of a 75% toluene solution of 2-norbornene (451.92 g, 4.8 mol in terms of NB), maleic anhydride (MAN, 470.69 g, 4.8 mol), and 2238.50 g of methyl ethyl ketone (MEK) and stirred to dissolve. Dissolved oxygen was then removed from the system by nitrogen bubbling, and the mixture was heated. When the internal temperature reached 80°C, a solution of dimethyl 2,2'-azobisisobutyrate (Wako Pure Chemical Industries, Ltd., trade name: V-601, 44.21 g, 0.19 mol) and pentaerythritol tetrakis(3-mercaptopropionate) (PEMP, 140.73 g, 0.29 mol) dissolved in 189.74 g of MEK was added over 1 hour. The reaction mixture was then further reacted at 80°C for 7 hours. The reaction mixture was then cooled to room temperature. The polymerization solution obtained above was added dropwise to 3686.4 g of methanol to precipitate a white solid. The obtained white solid was washed with 3686.4 g of methanol and then vacuum dried at a temperature of 120°C to obtain 908.1 g of a polymer (precursor polymer A) having structural units derived from 2-norbornene and structural units derived from maleic anhydride. The resulting polymer was measured by gel permeation chromatography (GPC) to find that it had a weight average molecular weight Mw of 3,500 and a polydispersity index (weight average molecular weight Mw) / (number average molecular weight Mn) of 1.52. The amount of sulfur in the obtained precursor polymer A was confirmed by flask combustion and elemental analysis by ion chromatography, and it was confirmed that elemental sulfur was present in raw polymer 1. In addition, GPC measurement of the reaction solution did not show any peaks for PEMP alone, and no unreacted PEMP remained, which further confirmed that raw polymer 1 13 C-NMR measurement confirmed that PEMP was incorporated into precursor polymer A.

[0137] [Synthesis Example 2] (Synthesis of Precursor Polymer B) 799.1 g of a polymer (precursor polymer B) was obtained in the same manner as in Synthesis Example 1, except that pentaerythritol tetrakis(3-mercaptopropionate) (PEMP) was not used. The resulting polymer was measured by gel permeation chromatography (GPC) to find that its weight-average molecular weight Mw was 11,700 and its polydispersity (weight-average molecular weight Mw) / (number-average molecular weight Mn) was 1.90. The results are shown in Table 1.

[0138] [Table 1]

[0139] (Polymer synthesis) [Synthesis Example 3] (Synthesis of Polymer A) The MAN unit of precursor polymer A was ring-opened with normal butanol, and then reacted with an epoxy group-containing (meth)acrylic compound (GMA) to synthesize polymer A. Details are described below. First, 92.4 g (1.248 mol) of n-butanol was added to 60 g of precursor polymer A (0.312 mol in terms of MAN), followed by the addition of 6.0 g (0.059 mol) of triethylamine and 0.30 g (0.0025 mol) of 4-dimethylaminopyridine, and the mixture was reacted for 16 hours at 70° C. After that, 44.4 g (0.312 mol) of GMA was added and the mixture was reacted for 8 hours at 70° C. to prepare a reaction solution. The reaction solution was diluted with MEK and treated with an aqueous formic acid solution to remove the aqueous phase. Polymer A was then purified using the following procedure. The polymer was reprecipitated with excess water. The polymer solid obtained by reprecipitation was washed twice with an excess amount of water. The resulting reaction product was dried at 40°C for 16 hours. As a result of the above, the structural units derived from maleic anhydride in Precursor Polymer A were ring-opened with normal butanol, and Polymer A was obtained in which the structural units were reacted with GMA. GPC measurement of polymer A confirmed the disappearance of the peak of the epoxy group-containing (meth)acrylic compound, which confirmed that the obtained polymer A did not contain any unreacted epoxy group-containing (meth)acrylic compound. 1 1 H-NMR measurement confirmed that Polymer A had a structure in which the ring was opened with n-butanol and a structure in which GMA was reacted. The unreacted carboxylic acid contained in polymer A is 1 Measurement by 1 H-NMR revealed that it was 20 mol %. The results are shown in Table 2.

[0140] [Synthesis Example 4] (Synthesis of Polymer B) Polymer B was synthesized in the same manner as in Synthesis Example 3, except that Precursor Polymer B was used. The results are shown in Table 2.

[0141] [Synthesis Example 5] (Synthesis of Polymer C) Polymer C was synthesized in the same manner as in Synthesis Example 3, except that 44.4 g (0.312 mol) of GMA and 40.6 g (0.312 mol) of BGE were added in combination. The unreacted carboxylic acid contained in polymer C is 1 Measurement by 1 H-NMR revealed that it was 7 mol %. The results are shown in Table 2.

[0142] [Synthesis Example 6] (Synthesis of Polymer D) Polymer D was synthesized in the same manner as in Synthesis Example 3, except that 4.4 g (0.031 mol) of GMA and 81.2 g (0.624 mol) of BGE were used in combination and reacted at a temperature of 90° C. for 8 hours. The unreacted carboxylic acid contained in polymer D is 1 Measurement by 1 H-NMR revealed that it was 1 mol % or less. The results are shown in Table 2.

[0143] [Synthesis Example 7] (Synthesis of Polymer E) The MAN unit of precursor polymer A was ring-opened with HEMA to synthesize polymer E. Details are explained below. First, 112.76 g of MEK was added to 60 g of precursor polymer A (0.312 mol of MAN) to prepare a solution. Next, 40.6 g (0.312 mol) of HEMA was added to the solution, followed by 6.0 g (0.059 mol) of triethylamine and 0.30 g of 4-dimethylaminopyridine (DMAP, 0.0025 mol). The reaction was carried out at 70°C for 16 hours to prepare a reaction solution. Polymer E was synthesized in the same manner as in Synthesis Example 3 except for the synthesis reaction. The results are shown in Table 2.

[0144] [Table 2]

[0145] [Polymers A to E] (Solubility of polymers in various solvents) Various solutions with a solid content of 50% were prepared for the polymers obtained in Synthesis Examples 3 to 7, and the solubility in each solvent was confirmed according to the following criteria. The results are shown in Table 3. ◯: Completely dissolved and colorless and transparent △: Cloudy ×: Insoluble

[0146] [Table 3]

[0147] [Examples 1 to 4, Comparative Example 1] (Preparation of polymer solution) 100 parts by mass of the polymers obtained in Synthesis Examples 3 to 7 were dissolved in propylene glycol monomethyl ether acetate (PGMEA) to prepare polymer solution 1 having a solid content concentration of 30% by mass.

[0148] (Preparation of Photosensitive Resin Composition) A photosensitive resin composition was prepared by dissolving the following components in propylene glycol monomethyl ether acetate (PGMEA) so that the total solids concentration was 30% by mass. Solid content in polymer solution (each polymer): 100 parts by mass Multifunctional acrylate (dipentaerythritol hexaacrylate) (manufactured by Shin-Nakamura Chemical Co., Ltd., A-DPH): 50 parts by mass Photopolymerization initiator (BASF, Irgacure OXE01): 5 parts by mass Adhesion aid (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.): 1 part by mass Surfactant (DIC Corporation, F-556): 0.5 parts by mass The obtained photosensitive resin composition was filtered, if necessary, through a PTFE membrane filter Millex-LS (manufactured by Merck Millipore) to remove insoluble matter.

[0149] <Evaluation method> The polymers synthesized in the Synthesis Examples and the photosensitive resin compositions obtained in the Examples and Comparative Examples were evaluated as follows.

[0150] (Weight average molecular weight (Mw) · Number average molecular weight (Mn) · Molecular weight distribution (PDI)) The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (PDI: Mw / Mn) are calculated using polystyrene equivalent values ​​obtained from the calibration curve of standard polystyrene (PS) obtained by GPC measurement. The measurement conditions are as follows. The results are shown in Table 1. Tosoh gel permeation chromatography device HLC-8320GPC Column: Tosoh TSK-GEL Supermultipore HZ-M Detector: RI detector for liquid chromatography Measurement temperature: 40℃ Solvent: THF Sample concentration: 2.0 mg / ml

[0151] [Transparency] The photosensitive resin composition was applied to a Corning glass substrate measuring 100 mm in length and 100 mm in width, dried at 100°C for 120 seconds, and then irradiated with g+h+i rays at an integrated light intensity of 100 mJ / cm using a g+h+i ray mask aligner (Canon Inc., PLA-501F (ultra-high pressure mercury lamp)). 2 The entire surface was exposed to light so that a resin film with a thickness of approximately 3.0 μm was obtained. This resin film was heated in an air atmosphere at 230° C. for 1 hour to obtain a cured film, and the light transmittance at wavelengths of 550 nm and 400 nm was evaluated using an ultraviolet-visible spectrophotometer, and the obtained transmittance was defined as the transparency of the cured film at each wavelength.

[0152] [Film forming property] The photosensitive resin composition was spin-coated onto a 3-inch silicon wafer and pre-baked using a hot plate at 100°C for 120 seconds to obtain a resin film. Resin films were formed with different thicknesses (1 μm, 50 μm, 100 μm), and the pre-baked surface was observed with an optical microscope to check for the presence or absence of cracks and evaluated according to the following criteria. 〇: No cracks ×: Cracks present

[0153] [Heat resistance] The cured film was heated at a temperature increase rate of 10°C / min using a Tg-DTA device (TG / DTA6200, manufactured by Seiko Instruments Inc.) to measure the 1% thermal weight loss temperature (Td1) and 5% thermal weight loss temperature (Td5).

[0154] [Table 4]

[0155] The adhesive composition (photosensitive resin composition) containing the polymer of this embodiment exhibited good solubility in various organic solvents and, furthermore, had excellent heat resistance, so that coloration was suppressed and transparency was excellent even after a heating test at 230° C. Furthermore, since the adhesive composition of this embodiment can form a thick film of 50 μm or more, it was expected that the resulting cured product would have excellent chemical resistance and insulating properties.

Claims

1. A polymer containing structural units represented by the following general formulas (1) to (4). 【Chemical 1】 (In general formula (1), R １ , R ２ , R ３ and R ４ are each independently a hydrogen atom or an organic group having 1 to 30 carbon atoms; a1 is 0, 1 or 2. In general formula (3), Q １ represents an alkyl group having 1 to 10 carbon atoms. In general formula (4), Q 2 represents a group containing one or more (meth)acryloyl groups, or a substituted or unsubstituted alkyl group having 2 to 10 carbon atoms and an oxygen atom (—O—) introduced into the carbon chain.

2. A polymer containing structural units represented by the following general formulas (1), (2) and (5): 【Chemistry 2】 (In general formula (1), R １ , R ２ , R ３ and R ４ are each independently a hydrogen atom or an organic group having 1 to 30 carbon atoms; a1 is 0, 1 or 2. In general formula (5), Q １ represents an alkyl group having 1 to 10 carbon atoms, and Q ２ represents a group containing one or more (meth)acryloyl groups, or a substituted or unsubstituted alkyl group having 2 to 10 carbon atoms and an oxygen atom (—O—) introduced into the carbon chain.

3. A polymer described in claim 1 or 2, wherein the group containing one or more (meth)acryloyl groups is a group represented by the following general formula (4a): 【Chemistry 3】 (In general formula (4a), X 10 represents a substituted or unsubstituted divalent organic group, and R represents a hydrogen atom or a methyl group.)

4. 4. The polymer according to claim 1, wherein the polymer is bonded via a thioether group derived from at least one thiol group of a bifunctional or higher functional thiol group-containing compound.

5. A varnish comprising the polymer according to any one of claims 1 to 4 and an organic solvent.

6. An adhesive composition comprising the polymer according to any one of claims 1 to 4.

7. 7. The adhesive composition according to claim 6, wherein a cured film having a thickness of 3 μm obtained by heating at 230° C. for 60 minutes has a transmittance of 97% or more for light with a wavelength of 550 nm.

8. The adhesive composition according to claim 7 , wherein the cured film has a transmittance of 95% or more for light with a wavelength of 400 nm.

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