JP2016060861A - Alkali-soluble resin and curable resin composition containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alkali-soluble resin enhancing its developability, capable of shortening pattern formation time and capable of manufacturing a curable resin composition having further enhanced productivity, and the curable resin composition using the same.SOLUTION: The alkali-soluble resin is a base polymer synthesized from a monomer component containing (a) a monomer which allows an acid group to be introduced to its side chain and (b) a monomer which allows a maleimide structure or an N-substituted maleimide structure to be introduced to its main chain, or a polymer obtained by introducing a carbon-carbon double bond to the base polymer, and the content of (b) the monomer which allows the maleimide structure or the N-substituted maleimide structure to be introduced to its main chain in the monomer component is 20 mass% or more in 100 mass% of the monomer component and weight average molecular weight is 40000 or less.SELECTED DRAWING: None

Description

  The present invention relates to an alkali-soluble resin, a curable resin composition containing the same, a cured product formed using the curable resin composition, a photospacer including the same, and a display device.

  In a liquid crystal cell of a liquid crystal display device, a liquid crystal layer is formed between a pair of substrates, and a spacer is disposed in order to keep the distance between the substrates constant. In recent years, columnar spacers (photo spacers) formed by photolithography have been used as the spacers (for example, Patent Documents 1 and 2). The photospacer is required to have properties such as adhesion to the glass substrate, flexibility to follow the compression force, and elastic recovery force when the compression force is relaxed.

  The photo-spacer is formed by applying a curable resin composition on a glass substrate, exposing it to a predetermined mask, and then developing it. For this reason, in addition to satisfying the above characteristics, the curable resin composition is required to have developability capable of quickly removing development residues.

  Patent Document 3 describes that a photosensitive resin composition for a photospacer having high solubility in a developer is obtained using an acrylic resin having a repeating unit having a cyclic structure in the main chain. High developability is required.

JP 2009-53663 A JP 2009-175647 A WO2014 / 038576

Accordingly, an object of the present invention is to provide an alkali-soluble resin capable of producing a curable resin composition having improved developability, reduced pattern formation time, and improved productivity.
Another object of the present invention is to provide a curable resin composition having improved developability, reduced pattern formation time, and improved productivity.
Still another object of the present invention is to provide a cured product (preferably a photospacer) and a display device having improved productivity while maintaining a high elastic recovery rate.

  In the acrylic resin having a repeating unit having a maleimide structure or an N-substituted maleimide structure in the main chain, the present inventors include a specific amount of the repeating unit and a specific molecular weight. Alkali-soluble resin capable of producing a curable resin composition having particularly excellent developability while having properties such as adhesion, flexibility capable of following compression force, and elastic recovery force when compression force is relaxed is obtained. As a result, the present invention has been completed.

  That is, the alkali-soluble resin of the present invention is synthesized from a monomer component containing (a) a monomer capable of introducing an acid group into the side chain and (b) a monomer capable of introducing a maleimide structure or an N-substituted maleimide structure into the main chain. Or an alkali-soluble resin which is a polymer obtained by introducing a carbon-carbon double bond into the base polymer, wherein (b) the main chain has a maleimide structure or Content of the monomer which can introduce | transduce an N-substituted maleimide structure is 20 mass% or more in 100 mass% of said monomer components, and a weight average molecular weight is 40000 or less.

In the alkali-soluble resin of the present invention, the amount (BU) of the monomer capable of introducing a maleimide structure or an N-substituted maleimide structure into the main chain (b) is the monomer capable of introducing an acid group into the side chain (a). It is preferable that BU / AU = 0.40 or more in terms of mass ratio with respect to the used amount (AU).
The monomer component preferably further includes (c) a monomer having an oxyalkylene group and capable of introducing two or more aromatic rings at the end of the side chain.

The curable resin composition of the present invention contains any one of the above alkali-soluble resins and a polyfunctional monomer.
The content ratio of the alkali-soluble resin and the polyfunctional monomer preferably satisfies the following (Equation 1) in terms of mass ratio.
(Alkali-soluble resin) / (Polyfunctional monomer) = 40/60 to 10/90 (Formula 1)

The cured product of the present invention is a cured product obtained by curing the curable resin composition.
Moreover, the photospacer of this invention contains the said hardened | cured material.
Furthermore, the display device of the present invention includes the photo spacer.

  ADVANTAGE OF THE INVENTION According to this invention, developability improves, pattern formation time is shortened, and the alkali-soluble resin which can manufacture curable resin composition which productivity improved can be provided. Moreover, developability improves, pattern formation time is shortened, and the curable resin composition which productivity improved can be provided. Further, it is possible to provide a cured product (preferably a photospacer) and a display device with improved productivity while maintaining a high elastic recovery rate.

(A) And (b) is an example of the schematic sectional drawing of the photo spacer of a favorable shape.

1. Alkali-soluble resin The alkali-soluble resin of the present invention comprises (a) a monomer capable of introducing an acid group in the side chain and (b) a monomer capable of introducing a maleimide structure or an N-substituted maleimide structure in the main chain as essential monomers. A base polymer obtained by synthesizing from a monomer component, or a polymer to which a compound having a carbon-carbon double bond is added with a part or all (preferably, part) of the acid groups of the base polymer as reaction sites It is.

  Any appropriate resin can be used as the alkali-soluble resin as long as the specific monomer is used. The alkali-soluble resin is preferably an acrylic resin, a polyester resin, or a polyether resin, and more preferably an acrylic resin.

1-1 Base polymer The base polymer is a monomer that contains (a) a monomer capable of introducing an acid group in the side chain and (b) a monomer capable of introducing a maleimide structure or an N-substituted maleimide structure in the main chain as essential monomers. Obtained by synthesis from components. (A) By synthesizing using a monomer capable of introducing an acid group into the side chain, the alkali-soluble resin has a repeating unit having an acid group in the side chain.

1-1-1 (a) Monomer capable of introducing an acid group into a side chain (a) Monomer capable of introducing an acid group into a side chain [hereinafter sometimes simply referred to as (a) acid group-introducing monomer] Originally, (a1) an acid group-containing monomer having an acid group and (a2) a monomer capable of imparting an acid group after polymerization are included. In addition, when using the monomer which can provide an acid group after (a2) superposition | polymerization, the process for giving an acid group (post-processing) which is mentioned later after superposition | polymerization is performed.

  (A1) Examples of the acid group-containing monomer include monomers having a carboxyl group such as (meth) acrylic acid, 2- (meth) acryloyloxyethyl succinic acid, and itaconic acid; maleic anhydride, itaconic anhydride, and the like And a monomer having a carboxylic acid anhydride group. Among these, a monomer having a carboxyl group is preferable, and (meth) acrylic acid is particularly preferable. Moreover, (a2) As a monomer which can provide an acid group after superposition | polymerization, the monomer which has hydroxyl groups, such as 2-hydroxyethyl (meth) acrylate; The monomer which has epoxy groups, such as glycidyl (meth) acrylate; 2-isocyanate And monomers having an isocyanate group such as natoethyl (meth) acrylate. (A) The acid group-introducing monomer may be used alone or in combination of two or more.

  The post-treatment for imparting acid groups varies depending on the type of monomer (a2) that can be used to impart acid groups after polymerization. For example, when a monomer having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate is used, for example, an acid anhydride such as succinic acid anhydride, tetrahydrophthalic acid anhydride, maleic acid anhydride is added. Can do. When a monomer having an epoxy group such as glycidyl (meth) acrylate is used, for example, a compound having an amino group and an acid group such as N-methylaminobenzoic acid or N-methylaminophenol is added, or For example, acid anhydrides such as succinic acid anhydride, tetrahydrophthalic acid anhydride, maleic acid anhydride and the like can be added to a hydroxyl group generated after adding an acid such as (meth) acrylic acid. When a monomer having an isocyanate group such as 2-isocyanatoethyl (meth) acrylate is used, for example, a compound having a hydroxyl group and an acid group such as 2-hydroxybutyric acid can be added.

  (A) The content of the acid group-introducing monomer is preferably 10% by mass or more, more preferably 15% by mass or more, and 80% by mass or less in 100% by mass of all monomer components used for synthesizing the base polymer. 70 mass% or less is preferable. (A) If the content of the acid group-introducing monomer is small, sufficient alkali developability may not be exhibited, and a carbon-carbon double bond as a radical polymerizable unsaturated double bond is sufficient for an alkali-soluble resin. There is a risk that the amount cannot be introduced. On the other hand, if the content of the (a) acid group-introducing monomer is too large, the proportion of the monomer capable of introducing a ring structure into the main chain (b) described later decreases, so that the heat resistance and substrate adhesion of the cured product are poor. It will be enough.

1-1-2 (b) Monomer that can introduce maleimide structure or N-substituted maleimide structure into main chain The alkali-soluble resin of the present invention can introduce (b) a maleimide structure or N-substituted maleimide structure into the main chain. The main chain has a repeating unit having a maleimide structure or an N-substituted maleimide structure by polymerizing a monomer component containing a monomer [hereinafter sometimes simply referred to as (b) a ring structure-introducing monomer].

  Specifically, the repeating unit having a maleimide structure or an N-substituted maleimide structure in the main chain is preferably at least one selected from repeating units represented by the following general formulas (1) to (3). More preferably, it is a repeating unit represented by the following general formula (1).

  (B) Examples of the ring structure-introducing monomer include maleimide, benzylmaleimide, phenylmaleimide, naphthylmaleimide, N-o-hydroxyphenylmaleimide, Nm-hydroxyphenylmaleimide, Np-hydroxyphenylmaleimide, and N-o. -Chlorophenylmaleimide, Nm-chlorophenylmaleimide, Np-chlorophenylmaleimide, N-o-methylphenylmaleimide, Nm-methylphenylmaleimide, Np-methylphenylmaleimide, N-o-methoxyphenylmaleimide, Aromatic substituted maleimides such as Nm-methoxyphenylmaleimide and Np-methoxyphenylmaleimide; cyclohexylmaleimide, methylmaleimide, ethylmaleimide, propylmaleimide, isopropylmale Alkyl-substituted maleimides such as de, and the like. Of these, aromatic substituted maleimides are preferred. Specifically, maleimide, benzyl maleimide, phenyl maleimide, and cyclohexyl maleimide are preferable, benzyl maleimide, phenyl maleimide, and cyclohexyl maleimide are more preferable, and benzyl maleimide is more preferable. These monomers may be used alone or in combination of two or more.

  (B) As the ring structure-introducing monomer, a monomer that can introduce an N-substituted maleimide structure into the main chain is preferable because it can be an amine and can be colored.

  (B) The usage-amount of a ring structure introduction | transduction monomer is 20 mass% or more (for example, 20-50 mass%) in 100 mass% of all the monomer components used in order to synthesize | combine a base polymer. (B) By using the amount of the ring structure-introducing monomer in this way, while having properties such as adhesion to the glass substrate, flexibility to follow the compression force, and elastic recovery force when relaxing the compression force, The development speed is high and the occurrence of development residue is suppressed, and particularly excellent developability can be obtained. The amount of the (b) ring structure introduction monomer is preferably 25 to 50% by mass, more preferably 30 to 50% by mass.

  The use amount (BU) of the above-mentioned (b) ring structure introduction monomer is BU / AU = 0.40 or more (for example, 0.40) in terms of mass ratio with respect to the use amount (AU) of the above-mentioned (a) acid group introduction monomer. ~ 1.5), more preferably 0.45 to 1.5. (B) By making the usage-amount (BU) of a ring structure introduction | transduction monomer into such a range, it can be set as alkali-soluble resin from which the curable resin composition excellent in developability is obtained.

1-1-3 (c) Monomer capable of introducing two or more aromatic rings into side chain The alkali-soluble resin of the present invention preferably has two or more aromatic rings in the side chain. By introducing two or more aromatic rings, the elastic recovery of the obtained cured product is further improved. The reason for this is not clear, but it is because the aromatic ring has a stack structure and the interaction is manifested, so it is not the hardness due to increasing the crosslinking density, but because the hardness due to the interaction is given. Guessed. The two or more aromatic rings may be a condensed ring such as a naphthalene ring or an anthracene ring.

  (C) Monomers capable of introducing two or more aromatic rings into the side chain include biphenyl (meth) acrylate, o-biphenyloxyethyl (meth) acrylate [ethoxylated o-phenylphenol (meth) acrylate], o- Biphenyloxyethoxyethyl (meth) acrylate, m-biphenyloxyethyl acrylate, p-biphenyloxyethyl (meth) acrylate, o-biphenyloxy-2-hydroxypropyl (meth) acrylate, p-biphenyloxy-2-hydroxypropyl ( (Meth) acrylate, m-biphenyloxy-2-hydroxypropyl (meth) acrylate, N- (meth) acryloyloxyethyl-o-biphenyl = carbamate, N- (meth) acryloyloxyethyl-p-biphenyl = carbamer And biphenyl group-containing monomers such as N-acryloyloxyethyl-p-biphenyl = carbamate], N- (meth) acryloyloxyethyl-m-biphenyl = carbamate, o-phenylphenol glycidyl ether acrylate, And naphthalene ring-containing monomers such as vinylnaphthalene, and terphenyl group-containing monomers such as terphenyl (meth) acrylate and o-terphenyloxyethyl (meth) acrylate. Among them, (c1) a monomer having an oxyalkylene group and capable of introducing two or more aromatic rings at the end of the side chain is preferred, a monomer represented by the following formula (4) or the following formula (5) is more preferred, and the following formula ( The monomer 5) is more preferable.

  In the monomer of the above formula (5), a smaller n tends to obtain a non-reverse tapered photo spacer described later. Specifically, when a monomer molecule containing two or more aromatic rings contains an oxyalkylene chain, it is preferable that 50% or more of the number of oxyalkylene chains n (number of added oxyalkylene groups) is 1. The average added mole number of the oxyalkylene group is preferably less than 2, more preferably less than 1.5, particularly preferably less than 1.2, and most preferably 1. As a monomer of the said Formula (5), a brand name "HRD-01" and Nippon Distillation Co., Ltd. can be used as a commercial item, for example.

  (C) The content of the monomer capable of introducing two or more aromatic rings into the side chain is preferably 5% by mass or more, preferably 8% by mass or more, in 100% by mass of all monomer components used for synthesizing the base polymer. Is more preferable, 70 mass% or less is preferable, and 60 mass% or less is more preferable. (C) When there are few monomers which can introduce | transduce two or more aromatic rings into a side chain, there exists a possibility that the hardness (improvement effect of an elastic recovery rate) of the hardened | cured material obtained may be insufficient. On the other hand, if (c) the content of two or more aromatic ring-introducing monomers in the side chain is excessive, the content of (a) acid group-introducing monomer or (b) ring structure-introducing monomer decreases, so alkali development There is a possibility that the heat resistance and substrate adhesion of the resulting cured product may be insufficient.

1-1-4 (d) Monomer capable of introducing two or more oxyalkylene groups into the side chain The alkali-soluble resin of the present invention further comprises two or more oxyalkylene groups in the side chain in addition to the structural units described above. You may have a unit. The structural unit having two or more oxyalkylene groups in the side chain can be obtained, for example, by polymerizing a monomer component containing a monomer capable of introducing (d) two or more oxyalkylene groups into the side chain. (D) As a monomer capable of introducing two or more oxyalkylene groups into the side chain, other than the above-mentioned monomer (c) capable of introducing two or more aromatic rings into the side chain, two or more oxyalkylene groups in the side chain Examples include monomers capable of introducing a group.

  As a structural unit which has a 2 or more oxyalkylene group in a side chain, the structural unit represented by following General formula (6) is mentioned, for example.

In the general formula (6), R ¹ , R ² and R ³ are each independently a hydrogen atom or a methyl group, preferably a hydrogen atom. R ⁴ is a linear or branched alkyl group having 1 to 20 carbon atoms, a linear or branched alkenyl group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms. And preferably a hydrogen atom, a linear alkyl group having 1 to 20 carbon atoms, a linear alkenyl group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group having 6 to 12 carbon atoms. More preferably a linear alkyl group having 1 to 10 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and still more preferably a linear alkyl group having 1 to 5 carbon atoms, A phenyl group or a biphenyl group, particularly preferably a methyl group, a phenyl group or a biphenyl group. In addition, the alkyl group, the alkenyl group, and the aromatic hydrocarbon group may have a substituent. AO represents an oxyalkylene group. The oxyalkylene group represented by AO has 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms, and even more preferably 2. The repeating unit may contain one or more oxyalkylene groups. x represents an integer of 0-2. y represents 0 or 1; m represents the average addition mole number of an oxyalkylene group and is 2 or more, preferably 2 to 100, more preferably 2 to 50, and further preferably 2 to 15.

  (D) As a monomer which can introduce | transduce two or more oxyalkylene groups into a side chain, the monomer represented by following General formula (7) is mentioned, for example.

In the general formula (7), R ¹ , R ² , R ³ , R ⁴ , AO, x, y, and m are as described in the general formula (6).

  Specific examples of the monomer represented by the general formula (7) include phenoxydiethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate (EO 4 mol), methoxypolyethylene glycol (meth) acrylate (EO 9 mol), and methoxypolyethylene. Glycol (meth) acrylate (EO 13 mol), methoxytriethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, butoxydiethylene glycol (meth) acrylate, 2-ethylhexyl diethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate , Methoxypolypropylene glycol (meth) acrylate, nonylphenoxypolyethylene glycol (me ) Acrylate (EO4-17 moles), nonylphenoxy polypropylene glycol (meth) acrylate (PO5 mol), EO-modified cresol (meth) acrylate (EO2 mol), and the like. In the present specification, for example, “EO2 mole”, “PO5 mole” and the like represent the average number of moles added of the oxyalkylene group.

  (D) The content of the monomer capable of introducing two or more oxyalkylene groups into the side chain is preferably 100% by mass to 55% by mass, based on 100% by mass of all monomer components used for synthesizing the base polymer. More preferably, it is 1 mass%-50 mass%, More preferably, it is 1 mass%-45 mass%.

  When the alkali-soluble resin has a repeating unit having two or more oxyalkylene groups in the side chain, the resulting cured product has a higher crosslink density and can form a cured product having higher strength. Can be obtained. The above-described effect is particularly remarkable when a curable resin composition is formed by combining such an alkali-soluble resin and a polyfunctional monomer described below (preferably a polyfunctional monomer having no oxyalkylene group). .

1-1-5 (e) Monomer capable of introducing amide bond into side chain It is also a preferred embodiment to introduce an amide bond into the alkali-soluble resin of the present invention. By introducing an amide bond, the strength of the cured product obtained from the curable resin composition can be further improved. The reason for this is not clear, but the presence of amide bonds increases the interaction between the polymer molecular chains, such as hydrogen bonds. Is presumed to be expressed.

  (E) A monomer capable of introducing an amide bond into the side chain is represented by the following general formula (8).

  In general formula (8), R (a) and R (b) each independently represent a hydrogen atom other than a (meth) acryloyl group, an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl group. Examples of the substituent include a phenyl group, a hydroxyl group, and an alkoxy group. R (a) and R (b) may form a ring structure composed of a nonmetallic atom together with the nitrogen atom bonded thereto, and examples thereof include a ring structure represented by the following general formula (9). .

  (E) Monomers capable of introducing an amide bond to the side chain include (meth) acryloylmorpholine (morpholino (meth) acrylate), (meth) acrylamide, N-methyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N-isobutyl (meth) acrylamide, Nt-butyl (meth) acrylamide, Nt-octyl (meth) acrylamide, diacetone (meth) acrylamide, N-hydroxymethyl (meth) Acrylamide, N-hydroxyethyl (meth) acrylamide, N-cyclohexyl (meth) acrylamide, N-phenyl (meth) acrylamide, N-benzyl (meth) acrylamide, N-triphenylmethyl (meth) acrylamide, N, N-dimethyl (Meth) acrylamide and the like, may be used alone or two or more thereof.

  (E) The content of the monomer capable of introducing an amide bond into the side chain is preferably 2% by mass or more, more preferably 5% by mass or more, out of 100% by mass of all monomer components used for synthesizing the base polymer. 70 mass% or less is preferable and 40 mass% or less is more preferable. (E) When there are few monomers which can introduce | transduce an amide bond into a side chain, sufficient intensity | strength may not express. (E) If there are too many monomers capable of introducing an amide bond in the side chain, the hydrophilicity may become too strong, which may reduce the adhesion to the substrate, and form a spacer with a good shape. It may be difficult.

1-1-6 Other copolymerizable monomers The monomer component used to obtain the base polymer is the above-mentioned monomer (a) capable of introducing an acid group into the side chain and (b) a ring structure introduced into the main chain. (C) a monomer that can introduce two or more aromatic rings into the side chain, (d) a monomer that can introduce two or more oxyalkylene groups into the side chain, (e) In addition to the monomer capable of introducing an amide bond in the side chain, other copolymerizable monomers can be included as required in order to further improve the properties of the obtained cured product. Examples of such copolymerizable monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n- (meth) acrylate. Butyl, isobutyl (meth) acrylate, t-butyl (meth) acrylate, methyl 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, ( (Meth) acrylic acid esters such as tricyclodecyl (meth) acrylate, dicyclopentanyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate; styrene, vinyltoluene, α -Aromatic vinyl compounds such as methylstyrene; Butadie such as butadiene and isoprene Or substituted butadiene compounds, ethylene, propylene, vinyl chloride, ethylene or substituted ethylene compound such as acrylonitrile, vinyl esters such as vinyl acetate and the like.

  Among these, (meth) acrylic acid esters are preferable. These other copolymerizable monomers may be used alone or in combination of two or more.

  When these other copolymerizable monomers are used, the content ratio in 100% by mass of all monomer components used for synthesizing the base polymer is not particularly limited, but is preferably 0% by mass to 55% by mass, more preferably Is 5% by mass to 50% by mass, more preferably 10% by mass to 45% by mass.

1-2 Alkali-soluble Resin Introduced With Carbon-Carbon Double Bond In Side Chain The alkali-soluble resin of the present invention is carbon-based with some or all (preferably, part) of the acid groups of the base polymer as reaction sites. It includes a polymer to which a compound having a carbon double bond is added. Thus, it is also a suitable aspect to introduce a carbon-carbon double bond into the side chain of the base polymer. The carbon-carbon double bond can also be introduced into the alkali-soluble resin by adding a polymer capable of introducing a carbon-carbon double bond to the side chain to the monomer component for synthesizing the base polymer.

  If the alkali-soluble resin has a repeating unit having a carbon-carbon double bond in the side chain, the alkali-soluble resins can be radically polymerized, or the alkali-soluble resin and the polyfunctional monomer can be radically polymerized. Therefore, a cured product that is three-dimensionally cross-linked can be obtained, and a curable resin composition that can form a cured product with higher exposure sensitivity and higher breaking strength can be obtained. A method for introducing a carbon-carbon double bond into the side chain of the alkali-soluble resin will be described later.

  The alkali-soluble resin is preferably a polymer to which a compound having a carbon-carbon double bond is added with a part or all (preferably, part) of the acid groups of the base polymer as a reaction site.

  The alkali-soluble resin of the present invention may be a random copolymer or a block copolymer.

1-3 Molecular Weight The weight average molecular weight of the alkali-soluble resin is 40,000 or less as measured by gel permeation chromatography (GPC) using a tetrahydrofuran (THF) solvent. The lower limit is preferably 2000. More preferably, it is 2000-25,000, More preferably, it is 3,000-25,000. In the alkali-soluble resin of the present invention, when the molecular weight is 40,000 or less, excellent developability is imparted to the curable resin composition, and at the same time, storage stability is excellent.

  The molecular weight distribution [weight average molecular weight (Mw) / number average molecular weight (Mn)] of the alkali-soluble resin is preferably 1.1 to 6, more preferably 1.2 to 4, particularly preferably 2 to 2. 4. When the molecular weight distribution is in the above range, the coating property and the chemical resistance of the cured product tend to be excellent.

  The acid value of the alkali-soluble resin is preferably 20 mgKOH / g to 300 mgKOH / g, more preferably 30 mgKOH / g to 200 mgKOH / g, and further preferably 40 mgKOH / g to 150 mgKOH / g. If it is such a range, the curable resin composition which can form the hardened | cured material which is more excellent in alkali developability, has less generation | occurrence | production of a development residue, and is more excellent in adhesiveness can be obtained.

1-4 Base Polymer Production Method The base polymer is synthesized by polymerizing monomer components for constituting the base polymer. The polymerization method is preferably a solution polymerization method, and the polymerization temperature and polymerization concentration (polymerization concentration = [total mass of monomer mixture / (total mass of monomer mixture + solvent mass)] × 100) are determined based on the monomer mixture used ( Although it depends on the composition and ratio of the monomer component) and the molecular weight of the target polymer, the polymerization temperature is preferably 40 to 150 ° C., the polymerization concentration is 5 to 60% by mass, and more preferably the polymerization temperature is 60 to 130. It is good to set it as 10 degreeC and polymerization concentration 10-50 mass%.

  In the present invention, a chain transfer agent may be used in the polymerization of the base polymer. As chain transfer agents, in addition to known monofunctional thiol compounds such as n-dodecyl mercaptan and β-mercaptopropionic acid, both terminal mercapto-modified polysiloxanes (manufactured by Shin-Etsu Silicone; X-22-167B; the following formula (10) ); R is an alkylene group), a side-chain polyfunctional mercapto-modified polysiloxane having a side chain mercapto-modified (manufactured by Shin-Etsu Silicone; KF2001, KF2004; the following formula (11); R is an alkylene group) Can be used.

  When both terminal mercapto-modified polysiloxane is used, a polymer in which two molecules of the base polymer are bonded via the both terminal mercapto-modified polysiloxane is obtained. When a side chain polyfunctional mercapto-modified polysiloxane is used, a branched polymer in which a base polymer is bonded to a side chain mercapto group is obtained. By using these mercapto-modified polysiloxanes, polysiloxane bonds are introduced into the resulting polymer. One or more of these mercapto-modified polysiloxanes may be used in combination with a known monofunctional thiol compound such as n-dodecyl mercaptan or β-mercaptopropionic acid. When a mercapto-modified polysiloxane is used, the elastic recovery rate is further improved. The reason for this is that by introducing a polysiloxane part that is sparingly soluble in a solvent into the polymer, the polysiloxane part aggregates in the resin composition, forming pseudo fine particles, and these pseudo fine particles are elastically recovered. Presumably because it contributes to the improvement of the rate.

  The chain transfer agent is preferably used in a range of 0.1 to 20 parts by mass, more preferably 0.2 to 20 parts by mass with respect to 100 parts by mass of all monomer components used for synthesizing the base polymer. 3 to 20 parts by mass is more preferable. Within this range, an alkali-soluble resin having a weight average molecular weight (Mw) of 40000 or less can be obtained. When Mw exceeds 40000, the storage stability of the finally obtained alkali-soluble resin is deteriorated.

  When a solvent is used in the polymerization of the monomer components, a solvent used in a normal radical polymerization reaction may be used. Specifically, for example, ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone; ethyl acetate, butyl acetate, propylene glycol monomethyl Esters such as ether acetate and 3-methoxybutyl acetate; Alcohols such as methanol, ethanol, isopropanol, n-butanol, ethylene glycol monomethyl ether, and propylene glycol monomethyl ether; Aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; Chloroform; dimethyl sulfoxide; and the like. These solvents may be used alone or in combination of two or more.

  When radically polymerizing the monomer component, a radical polymerization initiator that is usually used may be added as necessary. Although it does not specifically limit as a polymerization initiator, For example, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, t-amyl Organic peroxides such as peroxy-2-ethylhexanoate and t-butylperoxy-2-ethylhexanoate; 2,2′-azobis (isobutyronitrile), 1,1′-azobis (cyclohexane Carbonitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl-2,2′-azobis (2-methylpropionate) and the like. These polymerization initiators may be used alone or in combination of two or more. The amount of the initiator used may be appropriately set according to the composition of the monomer component to be used, the reaction conditions, the molecular weight of the target polymer, and the like, and is not particularly limited, but the weight average molecular weight is 30 without gelation. 1,000 parts by mass or less, more preferably from 0.1 parts by mass to 15 parts by mass, and more preferably from 0.5 parts by mass to 10 parts by mass with respect to 100 parts by mass of all monomer components. .

1-5 Giving a carbon-carbon double bond to an alkali-soluble resin Giving a carbon-carbon double bond to an alkali-soluble resin reacts part or all (preferably part) of the acid groups of the base polymer. It can be carried out by adding a compound having a carbon-carbon double bond as a point. The carbon-carbon double bond introduction reaction to the base polymer can be performed by a known method, and in the presence of oxygen or other polymerization inhibitor and catalyst, the carbon-carbon double bond introduction monomer is converted into an acid group in the base polymer. Can be reacted.

The treatment for imparting a carbon-carbon double bond to the base polymer differs depending on the type of monomer capable of introducing an acid group into the side chain (a) used in obtaining the base polymer, and examples thereof include the following methods. It is done.
(I) (a) When a monomer having a carboxyl group such as (meth) acrylic acid or itaconic acid is used as a monomer capable of introducing an acid group into the side chain:
Add a compound having an epoxy group and a double bond such as glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, o- (or m-, or p-) vinylbenzyl glycidyl ether A compound having an isocyanate group and a double bond such as 2-isocyanatoethyl (meth) acrylate, or a vinyl ether group such as 2-vinyloxyethoxyethyl (meth) acrylate and a carbon-carbon double bond. The compound having can be added.
(Ii) (a) When a monomer having a carboxylic acid anhydride group such as maleic anhydride or itaconic anhydride is used as a monomer capable of introducing an acid group into the side chain:
A compound having a hydroxyl group and a carbon-carbon double bond such as 2-hydroxyethyl (meth) acrylate can be added.
(Iii) (a) As a monomer capable of introducing an acid group into the side chain, glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, o- (or m-, or p-) vinylbenzyl When using a monomer having an epoxy group such as glycidyl ether:
A compound having an acid group such as (meth) acrylic acid and a polymerizable carbon-carbon double bond can be added.

  Among these, the method of adding glycidyl (meth) acrylate to the acid groups in the base polymer (including cases where they are imparted by post-treatment) is advantageous in that it is simple and less colored. In addition, since an acid group is consumed by this carbon-carbon double bond introduction reaction, the amount of the acid group consumed (carbon-carbon double bond introduction amount) is taken into consideration, and (a) acid in the monomer component It is preferable to determine the amount of the group-introduced monomer used. It is because there exists a possibility that alkali developability may not be expressed when there are too few acid groups in alkali-soluble resin. Therefore, the acid value of the alkali-soluble resin finally obtained from the above viewpoint is preferably about 20 to 250 mgKOH / g, more preferably 30 to 200 mgKOH / g, and still more preferably 35 to 150 mgKOH / g.

  The glycidyl acrylate is preferably reacted in an amount of 5 parts by mass or more, more preferably 10 parts by mass or more, and particularly preferably 15 parts by mass or more with respect to 100 parts by mass of the base polymer. If the amount of glycidyl (meth) acrylate is less than 5 parts by mass, the amount of double bonds in the side chain of the resulting alkali-soluble resin is too small, and the exposure sensitivity is reduced, or a dense cured coating film cannot be formed. There is a risk that the characteristics may deteriorate. In addition, the hydroxyl group produced by adding glycidyl (meth) acrylate to the acid group has the effect of increasing the solubility in an alkali developer, but the solubility in the alkali developer is insufficient due to the reduction of the hydroxyl group. There is a risk. The addition amount of glycidyl (meth) acrylate is preferably 170 parts by mass or less, more preferably 150 parts by mass or less, and still more preferably 140 parts by mass or less with respect to 100 parts by mass of the base polymer. When the addition amount of (meth) acrylic acid glycidyl is too large, the storage stability of the resin composition may decrease, or the solubility in an organic solvent may decrease.

  In addition, the introduction of a carbon-carbon double bond into the side chain of the alkali-soluble resin is carried out by synthesizing a base polymer by adding a monomer obtained by ring-opening addition reaction of (meth) acrylic acid to a cyclic lactone to the monomer component. The terminal carboxyl group of the derived structural unit can be modified by, for example, 3,4-epoxycyclohexyl (meth) acrylate or the like. Moreover, the method etc. etc. which make cyclic lactone react with the carboxyl group of a base polymer, and are modified | denatured with a 3, 4- epoxy cyclohexyl (meth) acrylate etc. then are mentioned. The ring-opening addition reaction of the cyclic lactone and modification with 3,4-epoxycyclohexyl (meth) acrylate can be performed by known methods.

2. Curable resin composition The curable resin composition of this invention contains the said alkali-soluble resin and a polyfunctional monomer. Practically, the curable resin composition of the present invention may further contain a polymerization initiator (preferably a photopolymerization initiator), a solvent and an additive.
The curable resin composition of the present invention is particularly preferably used for a negative photosensitive resin composition.

  If the curable resin composition of the present invention is used, a cured product (preferably a photospacer) can be formed by photolithography. In the curable resin composition of the present invention, the content of the alkali-soluble resin is preferably included in an amount of 5 to 60% by mass with respect to the solid content of the curable resin composition. In addition, solid content means the mass part of the component (except the solvent volatilized at the time of formation of hardened | cured material) which forms hardened | cured material so that it may obtain | require with the measuring method mentioned later.

2-1 Polyfunctional monomer As the polyfunctional monomer contained in the curable resin composition of the present invention, a compound having at least two ethylenically unsaturated double bonds in the molecule is preferable. In view of ease of radical polymerization, a polyfunctional monomer having an acrylic group is more preferable.

  Examples of the polyfunctional monomer include polyfunctional aromatic vinyl monomers such as divinylbenzene, diallyl phthalate, and diallylbenzene phosphonate; (di) ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, trimethylolpropane di (Meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol di (meth) acrylate, dipentaerythritol Tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol Hexa (meth) acrylate, tripentaerythritol di (meth) acrylate, tripentaerythritol tri (meth) acrylate, tripentaerythritol tetra (meth) acrylate, tripentaerythritol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate , Multifunctional (meth) acrylates such as tripentaerythritol hepta (meth) acrylate, tripentaerythritol octa (meth) acrylate, tris (hydroxyethyl) isocyanurate tri (meth) acrylate; these monomers are modified with caprolactone or alkylene oxide Examples include modified polyfunctional monomers.

  Among them, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tripentaerythritol hepta (meth) acrylate, tripentaerythritol octa (meth) acrylate, Tris (hydroxyethyl) isocyanurate tri (meth) acrylate and the like are preferable. If these polyfunctional monomers are used, a cured product having a high crosslinking density can be obtained because of the large number of functional groups.

  The functional number of the polyfunctional (meth) acrylates is preferably 4 or more, and more preferably 5 or more. Further, from the viewpoint of further suppressing curing shrinkage, the functional number is preferably 10 or less, more preferably 9 or less, and still more preferably 8 or less. Moreover, although it does not specifically limit as molecular weight, From a viewpoint of handling, 2000 or less is suitable, for example.

  In the present invention, the polyfunctional monomer may or may not have an oxyalkylene group. Preferably, a polyfunctional monomer having no oxyalkylene group is used.

  The content ratio of the polyfunctional monomer is preferably 30 parts by mass to 95 parts by mass, more preferably 40 parts by mass to 90 parts by mass, and still more preferably 55 parts in 100 parts by mass of the solid content of the curable resin composition. Part by mass to 90 parts by mass.

In this invention, it is preferable that the content rate of the said alkali-soluble resin and a polyfunctional monomer satisfy | fills the following (Formula 1) by mass ratio.
(Alkali-soluble resin) / (Polyfunctional monomer) = 40/60 to 10/90 (Formula 1)
More preferably, the following (Formula 2) is satisfied.
(Alkali-soluble resin) / (Polyfunctional monomer) = 35 / 65-15 / 85 (Formula 2)
By satisfy | filling the said relational expression, there exists a tendency which can maintain high developability and the elastic recovery rate of the hardened | cured material obtained.

2-2 Polymerization initiator The curable resin composition of this invention contains a polymerization initiator practically. Of these, a photopolymerization initiator is preferred. Any photopolymerization initiator may be used as long as it is decomposed and / or reacted with light (including ultraviolet rays and electron beams) to generate radicals.

  Examples of the photopolymerization initiator include benzoin such as benzoin, benzoin methyl ether, and benzoin ethyl ether and alkyl ethers thereof; acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, and 1,1-dichloroacetophenone. Anthraquinones such as 2-methylanthraquinone, 2-amylanthraquinone, 2-t-butylanthraquinone and 1-chloroanthraquinone; thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone and 2-chlorothioxanthone; Ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone; 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino- Α-aminoketones such as lopan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1; 2-hydroxy-1- {4- [4- (2-hydroxy Α-hydroxy ketones such as 2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one; acylphosphine oxides and xanthones. These photopolymerization initiators may be used alone or in combination of two or more.

  Among these, α-aminoketone compounds are preferably used, and α-aminoketone compounds represented by the following general formula (12) are more preferably used. By using such a compound, it is possible to obtain a curable resin composition capable of forming a photospacer having a non-inverted taper shape and a small diameter.

In the general formula (12), X ¹ and X ² are each independently a methyl group, an ethyl group, a benzyl group or a 4-methylbenzyl group, preferably a methyl group. —NX ³ X ⁴ is a dimethylamino group, a diethylamino group or a morpholino group, preferably a dimethylamino group or a morpholino group, more preferably a morpholino group. X ⁵ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkylthio group having 1 to 8 carbon atoms, a dimethylamino group, or a morpholino group, preferably carbon It is an alkylthio group or morpholino group having 1 to 8 carbon atoms, more preferably an alkylthio group or morpholino group having 1 to 3 carbon atoms, and further preferably a methylthio group.

  More preferably, an α-hydroxyketone compound may be used in combination, more preferably an α-hydroxyketone compound represented by the following general formula (13) or the following general formula (14) is used. An α-hydroxyketone compound represented by the general formula (14) is used. By using such a compound, it is possible to obtain a curable resin composition capable of forming a photospacer having a non-inverted taper shape and a small diameter.

In general formula (13), X ⁶ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Or it is a C1-C5 alkoxy group, More preferably, it is a hydrogen atom or a C1-C2 alkoxy group. X ⁷ and X ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group. X ⁷ and X ⁸ may be bonded to each other to form a cycloalkyl group having 4 to 8 carbon atoms (preferably 6 to 8, more preferably 6).

In General Formula (14), X ^{9 to} X ¹² are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 5 carbon atoms, more preferably It is a methyl group. X ⁹ and X ¹⁰ and / or X ¹¹ and X ¹² may be bonded to each other to form a cycloalkyl group having 4 to 8 carbon atoms.

  The alkyl group, alkoxy group, alkyl group and cycloalkyl group may have a substituent. As said substituent, a hydroxyl group, a carboxyl group, a sulfo group, a cyano group, a halogen atom etc. are mentioned, for example.

  The content of the photopolymerization initiator is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more in the solid content of the curable resin composition. Moreover, 40 mass% or less is preferable, 20 mass% or less is more preferable, and 10 mass% or less is especially preferable.

  Moreover, the content ratio of the photopolymerization initiator is preferably 0.1 parts by mass to 40 parts by mass, more preferably 0.5 parts with respect to 100 parts by mass of the total mass of the alkali-soluble resin and the polyfunctional monomer. It is 1 to 10 parts by mass, particularly preferably 1 to 10 parts by mass. By setting it as the said range, radical curing can be advanced more fully, and prevention of elution of the remaining radical polymerization initiator etc. and ensuring of solvent resistance become easier.

  Further, in addition to the photopolymerization initiator, a photopolymerization initiation assistant may be used in combination. Photopolymerization initiation assistants can also be used in combination. Specific examples of the photopolymerization initiation assistant include 1,3,5-tris (3-mercaptopropionyloxyethyl) -isocyanurate, 1,3,5-tris (3-mercaptobutyloxyethyl) -isocyanurate (Showa Trifunctional thiol compounds such as Karenz MT (registered trademark) NR1), trimethylolpropane tris (3-mercaptopropionate), etc .; pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3- Examples thereof include tetrafunctional thiol compounds such as mercaptobutyrate (made by Showa Denko KK, Karenz MT (registered trademark) PE1); and polyfunctional thiols such as hexafunctional thiol compounds such as dipentaerythritol hexakis (3-propionate).

2-3 Additives The curable resin composition of the present invention may contain any appropriate additive as necessary. Examples of the additives include fillers such as aluminum hydroxide, talc, clay, barium sulfate, dyes, pigments, antifoaming agents, coupling agents (preferably silane coupling agents), leveling agents, sensitizers, release agents. Examples include molds, lubricants, plasticizers, antioxidants, ultraviolet absorbers, flame retardants, polymerization inhibitors, thickeners, dispersants, and inorganic materials.

  The curable resin composition of the present invention may contain a polymerization inhibitor. By containing a polymerization inhibitor, the storage stability of the curable resin composition is improved, and the resolution after development is improved depending on the application. Specific examples of the polymerization inhibitor include phenol, catechol, resorcinol, hydroquinone, 4-t-butylcatechol, 2,6-di (t-butyl) -p-cresol, phenothiazine, 4-methoxyphenol and the like.

  The content of the polymerization inhibitor is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more in the solid content of the curable resin composition. On the other hand, from the viewpoint of keeping the hardness of the cured product high, it is preferably 5% by mass or less, and more preferably 1% by mass or less.

  The curable resin composition of the present invention may contain an ultraviolet absorber (UV absorber). When manufacturing the spacer, the lower diameter tends to be larger than the upper diameter. This is because the light reaching the glass substrate is reflected, and the coating film on the bottom of the spacer reflects the incident light from above and the glass substrate. This is because both the reflected light from the light is received and photocuring proceeds excessively. When an ultraviolet absorber is contained in the composition, excessive light energy is absorbed, so that the increase in the lower diameter of the spacer can be effectively suppressed.

  As the ultraviolet absorber, those having a maximum absorption wavelength (peak) at a wavelength of 280 to 380 nm are preferable. This is because it does not overlap with the peak of the photopolymerization initiator. Specifically, a compound represented by the following chemical formula is preferable because the maximum absorption wavelength does not overlap with the peak of the photopolymerization initiator and is easily available.

  Among the above compounds, Tinuvin (registered trademark) series and CHIMASSORB (registered trademark) can be obtained from BASF Japan, and SEESORB (registered trademark) from Cypro Kasei.

  The amount of the ultraviolet absorber is preferably 0.03 to 1.0% by mass in 100% by mass of the solid content of the curable resin composition. Within this range, it is possible to obtain a spacer having a level of elastic recovery with no problem in practical use and a small lower diameter. If the ultraviolet absorber is added too much, the upper side of the spacer is cured even if the amount of the photopolymerization initiator is increased, but the lower side may be insufficiently cured, which is not preferable. On the other hand, if the ultraviolet absorber is less than 0.03% by mass, it is not possible to absorb excess light, and the suppression of reflected light to the glass substrate becomes insufficient, and the lower diameter of the spacer may not be reduced. . The ultraviolet absorber is more preferably 0.05% by mass or more, further preferably 0.1% by mass or more, more preferably 1.0% by mass or less, further preferably 0.75% by mass or less, and 0.6% by mass. The following are particularly preferred:

  The content ratio of the ultraviolet absorber is preferably 0.05 parts by mass to 10 parts by mass, more preferably 0.1 parts by mass to 5 parts by mass with respect to 100 parts by mass in total of the alkali-soluble resin and the polyfunctional monomer. Yes, and more preferably 0.2 to 3 parts by mass. When the content of the ultraviolet absorber exceeds 10 parts by mass, a non-reverse tapered photo spacer may not be obtained.

  The curable resin composition of the present invention does not require a coupling agent to develop the adhesion to the substrate, but can further develop the adhesion by adding an appropriate amount of the coupling agent.

  The coupling agent has a property of binding to an oxidized surface of an inorganic substance through a hydrolysis reaction or a condensation reaction. Specifically, as such a coupling agent, for example, a coupling agent having a reactive group such as a vinyl group, a (meth) acryl group, an epoxy group, an amino group, a mercapto group, or an isocyanate is preferable. Especially, what has a vinyl group, a (meth) acryloyl group, and / or an epoxy group as a reactive group is preferable. More preferred is a (meth) acryloyl group. Moreover, what contains silicon, a zirconia, titanium, and / or aluminum etc. as a center metal is suitable, for example, what has silicon as a center metal is preferable, More preferably, it is a silane coupling agent. By using a silane coupling agent, the adhesion and surface hardness of the cured product can be made more satisfactory. The content of the coupling agent is suitably 0.5% by mass or more in 100% by mass of the total solid content of the curable resin composition. From the viewpoint of storage stability of the curable resin composition, it is preferably 20% by mass or less. More preferably, it is 15 mass% or less, More preferably, it is 10 mass% or less.

2-4 Solvent The curable resin composition of the present invention may contain any appropriate solvent. Examples of the solvent include ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, 3-methoxy Esters such as butyl acetate; Alcohols such as methanol, ethanol, isopropanol, n-butanol, ethylene glycol monomethyl ether, and propylene glycol monomethyl ether; Aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; Chloroform, dimethyl sulfoxide, and the like Can be mentioned. The amount of the solvent can be set to any appropriate amount depending on the desired viscosity of the curable resin composition.

  An ester solvent is preferably used as the solvent used in the polymerization of the alkali-soluble resin in that each component can be uniformly dissolved and developability and transparency can be improved. Moreover, the compound whose boiling point under atmospheric pressure is 110-250 degreeC is more preferable.

  By setting the boiling point to 110 ° C. or higher, drying proceeds appropriately at the time of curing, and a good cured product is obtained. On the other hand, when the boiling point is 250 ° C. or lower, the amount of residual solvent in the cured product can be suppressed to a small level, and the curing shrinkage during thermal curing can be further reduced, so that a better cured product can be obtained.

  The curable resin composition of the present invention may contain various solvents such as acetates, ketones and ethers other than those described above.

  In particular, a form in which an ester solvent and an alcohol solvent are used in combination as a solvent is one of the preferred forms, and the amount of the alcohol solvent is more preferably 25% by mass or less with respect to 100% by mass of the total solvent. 20% by mass or less is particularly preferable.

  There is no restriction | limiting in particular in content of the solvent in the curable resin composition of this invention, According to a use, it can use arbitrary quantity. For example, the solvent amount is preferably 40 to 90% by mass of the entire curable resin composition.

2-5 Use of Curable Resin Composition The curable resin composition of the present invention is excellent in developability and curability and can accurately form a molded product having a desired shape. Such a curable resin composition of the present invention can be used, for example, for forming a photospacer, as well as a photocurable paint and a photocurable ink. It can also be used as a material for color filters, overcoats, insulating films, protective films and the like.

2-6 Method for Producing Curable Resin Composition The curable resin composition of the present invention can be selected from, for example, an alkali-soluble resin, a polyfunctional monomer, a photopolymerization initiator, and optionally a radical polymerizable oligomer and other additives. It is obtained by filtering the obtained solution after stirring and dissolving uniformly.

3. Cured Product The cured product of the present invention is obtained by curing the curable resin composition (preferably a photo spacer described later). The method for forming the cured product is not particularly limited. For example, the curable resin composition is applied to a substrate such as glass or a transparent plastic film, dried to form a coating film, and then photolithography is performed. Can be formed. Since the hardened | cured material of this invention is manufactured from the said curable resin composition which developability improved, pattern formation time was shortened, and productivity improved, productivity is high, maintaining a high elastic recovery rate.

  In development, an aqueous alkali solution is preferably used. Highly sensitive development can be performed with little impact on the environment. As the alkali component, potassium hydroxide, sodium hydroxide, sodium carbonate and the like are preferable. The alkali concentration is preferably 0.01 to 5% by mass, more preferably 0.02 to 3% by mass, and most preferably 0.03 to 1% by mass. If the alkali concentration is lower than the above range, the solubility of the curable resin may be insufficient. Conversely, if the alkali concentration is high, the dissolving power may be too high and developability may be poor. Further, a surfactant may be added to the alkaline aqueous solution.

In photolithography, for example, a UV aligner (TME-150RNS, manufactured by TOPCON) having a photomask disposed at a distance of about 150 μm from the coating film and equipped with a 2.0 kW ultrahigh pressure mercury lamp has an intensity of 50 mJ / cm ² ( The coating film of the curable resin composition is photocured by irradiating ultraviolet rays at 365 nm illuminance. After UV irradiation, a 0.05% by weight potassium hydroxide aqueous solution is sprayed on the coating film with a spin developing machine for 40 seconds to dissolve and remove the unexposed area, and the remaining exposed area is washed with pure water for 10 seconds. By developing, a cured product (columnar molded body) can be obtained. Thereafter, post-baking (post-heating) may be performed. The distance to the photomask, UV intensity, development conditions, and the like can be changed as appropriate.

4). Photospacer The photospacer of the present invention contains the cured product. The photospacer of this invention can be obtained using the said curable resin composition. If the said curable resin composition is used, the photo-spacer which is excellent in board | substrate adhesiveness, and an elastic recovery rate and a high fracture strength can be formed. Furthermore, the photo spacer of the present invention is excellent in shape by being produced by photolithography using the curable resin composition of the present invention. For example, it is possible to obtain a photo spacer 10 [FIG. 1 (a)] having substantially no diameter difference in the height direction, or a photo spacer 20 [FIG. 1 (b)] whose upper part is narrower than the lower part. In the present specification, a shape having substantially no diameter difference in the height direction and a shape whose upper part is narrower than the lower part are collectively referred to as “non-reverse tapered shape”.

  The photospacer of the present invention can be suitably used as a spacer for a liquid crystal display, more specifically, a liquid crystal cell of a liquid crystal display.

  The photospacer can be formed by photolithography. Specifically, after the curable resin composition is applied to a substrate and dried, a photomask is placed on the obtained coating film to expose it, the coating film is cured, and then developed to obtain a photo Spacers can be formed. According to photolithography, a photo spacer can be formed at an arbitrary position. For example, in a liquid crystal display device, a photo spacer is formed only on a black matrix to prevent display characteristics from being deteriorated due to the spacer. can do.

  Examples of the method for applying the curable resin composition include a method using a spin coater, a bar coater, a gravure coater, a roll coater, a knife coater, an applicator and the like. The drying temperature is preferably 40 ° C to 200 ° C, more preferably 70 ° C to 100 ° C. The drying time is preferably 1 minute to 30 minutes, more preferably 2 minutes to 10 minutes.

  The photomask is arranged at any appropriate position depending on the desired size of the photospacer. A photomask is arrange | positioned at the upper part of a coating film, The distance of a coating film and a photomask becomes like this. Preferably they are 0 micrometer-500 micrometers, More preferably, they are 10 micrometers-400 micrometers.

UV radiation intensity during the exposure (365 nm intensity equivalent), preferably ^{10mJ / cm 2 ~200mJ / cm 2} , more preferably ^{20mJ / cm 2 ~150mJ / cm 2} .

  In the development, an alkaline aqueous solution is preferably used. This is because high-sensitivity development can be performed with less environmental burden. As the alkaline component, for example, potassium hydroxide, sodium hydroxide, sodium carbonate or the like is used. The alkali concentration of the aqueous alkali solution is preferably 0.01% by mass to 5% by mass, and more preferably 0.02% by mass to 3% by mass. If it is such a range, the said curable resin composition can be melt | dissolved appropriately and a photo spacer can be formed with sufficient developability. A surfactant may be further added to the alkaline aqueous solution.

  You may post-bake after image development. The heating temperature during post-baking is preferably 150 ° C to 300 ° C, more preferably 180 ° C to 250 ° C. The heating time is preferably 10 minutes to 90 minutes, more preferably 20 minutes to 60 minutes. When the curable resin composition of the present invention contains an alkali-soluble resin having a structural unit having two or more oxyalkylene groups in the side chain, a photo spacer having a high crosslinking density can be formed by post-baking.

Examples of the shape of the photospacer of the present invention include a columnar shape, a prismatic shape, a truncated cone shape, and a truncated pyramid shape. Thickness at the bottom of the photo spacers, in terms of the horizontal cross-sectional area of the photo spacers, preferably 3μm ² ~500μm ^2, more preferably 15μm ² ~100μm ^2. When the shape of the photo spacer is a columnar shape or a truncated cone shape, the diameter of the lowermost portion of the photo spacer can be set to any appropriate range. Practically, it is preferably 2 μm to 20 μm, more preferably 3 μm to 10 μm. The height of the photo spacer can be set to any appropriate height depending on the desired substrate interval. The height of the photo spacer is, for example, 1 μm to 10 μm.

  As described above, the photospacer of the present invention preferably has a non-reverse tapered shape. The horizontal cross-sectional area A1 of the portion H1 separated from the lower part of the photo spacer in the height direction (height L × 1/2 of the photo spacer) and in the height direction from the lower part of the photo spacer (height L × 1 of the photo spacer / 4) The ratio (A2 / A1) of the distant portion H2 to the horizontal sectional area A2 is preferably 1 to 1.3, more preferably 1 to 1.2. A photospacer having such a range of A2 / A1 has excellent substrate adhesion, and has a high elastic recovery rate and high fracture strength. Further, the photo spacer can prevent bubbles from being mixed into the liquid crystal layer, and can contribute to the improvement of the display performance of the display device.

  In one embodiment, the compression ratio of the photospacer of the present invention is 10% to 90%. A method for evaluating the compression rate will be described later.

  The lower limit of the elastic recovery rate of the photospacer of the present invention is preferably 55% or more, more preferably 60% or more, and further preferably 65% or more. The larger the elastic recovery rate, the better. The upper limit of the elastic recovery rate of the photospacer of the present invention is, for example, 100%. By using a photospacer with a high elastic recovery rate, problems in manufacturing a liquid crystal cell can be solved. The method for evaluating the elastic recovery rate will be described later.

  In one embodiment, when the diameter of the lowermost part of the photospacer having a cylindrical shape or a truncated cone shape is 6 μm to 8 μm, the elastic recovery rate of the photospacer of the present invention is preferably 65% to 100%. It is.

  The relationship between the elastic recovery rate b (%) of the photospacer of the present invention and the diameter a (μm) at the lowermost part of the photospacer when the photospacer shape is cylindrical or truncated cone is a practical diameter. In the range of a, preferably b> 3.1a + 45.

  The breaking strength of the photo spacer of the present invention is preferably 20 mN or more (for example, 20 to 300 mN), more preferably 50 mN or more. The greater the breaking strength, the better.

  In one embodiment, when the diameter of the lowermost part of the photospacer having a cylindrical shape or a truncated cone shape is 6 μm to 8 μm, the breaking strength of the photospacer of the present invention is preferably 145 mN to 300 mN.

5. Display Device The present invention includes a display device (preferably a liquid crystal display device) using the photospacer of the present invention. The basic configuration of the liquid crystal display device includes: (a) a driving side substrate in which driving elements such as thin film transistors (TFTs) and pixel electrodes (conductive layers) are arranged; and a counter electrode (conductive layer). The counter substrate is arranged to be opposed to each other with a photo spacer interposed therebetween, and a liquid crystal material is sealed in the gap, and (b) the driving substrate and the counter substrate having the counter electrode (conductive layer) are arranged as a photo spacer. The liquid crystal display device of the present invention can be suitably applied to various types of liquid crystal display devices. The configuration and materials used for the liquid crystal display device are not particularly limited, and any known configuration or material can be used. For example, the configurations and materials disclosed in JP 2011-180549 A and JP 2009-162871 A can be employed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these. The examples and comparative examples were evaluated as follows. Moreover, below, a part means a mass part and% means the mass%.

[Evaluation method]
(1) Weight average molecular weight: Mw
GPC (HLC-8220GPC, manufactured by Tosoh Corporation) was used as an eluent, and TSKgel SuperHZM-N (manufactured by Tosoh Corporation) was used as a column for the measurement.

(2) Solid content About 0.3 g of the copolymer solution prepared in Example A-1 to Example A-8 and Comparative Example A-9 and Comparative Example A-10 was weighed into an aluminum cup, and about 1 g of acetone was added. After adding and dissolving, it was naturally dried at room temperature. Thereafter, using a hot air dryer (trade name: PHH-101, manufactured by ESPEC Corp.), it was dried at 140 ° C. for 3 hours, then allowed to cool in a desiccator, and the weight was measured. From the weight loss, the weight of the solid content (acrylic resin) of the polymer solution was calculated.

(3) Acid value 1.5 g of the copolymer solution prepared in Example A-1 to Example A-8 and Comparative Example A-9 and Comparative Example A-10 was precisely weighed and mixed with 90 g of acetone and 10 g of water. It was dissolved in a solvent and titrated with a 0.1N aqueous KOH solution. Titration was performed using an automatic titrator (trade name: COM-555, manufactured by Hiranuma Sangyo Co., Ltd.), and the acid value per 1 g of polymer was determined from the solid content concentration (mgKOH / g).

(4) Evaluation of developability The curable resin composition was applied onto a 10 cm square glass substrate with a spin coater and dried in an oven at 90 ° C. for 3 minutes to form a coating film. After drying, an intensity of 50 mJ / cm ² by a UV aligner (TME-150RNS, manufactured by TOPCON) equipped with a 2.0 kW ultrahigh pressure mercury lamp and an 8 μmφ pattern photomask placed at a distance of 100 μm from the coating film Ultraviolet rays were irradiated (in terms of 365 nm illuminance). After UV irradiation, 0.05% aqueous potassium hydroxide solution is sprayed on the coating film with a spin developing machine for 20 to 90 seconds to dissolve and remove the unexposed area, and the remaining exposed area is 10% with pure water. Development was carried out by washing with water for 2 seconds. The spacer formed after development was confirmed with a laser microscope (VK-9700, manufactured by Keyence Corporation). The development time was evaluated by measuring the shortest spraying time (break time) during which the unexposed areas were completely removed.
Moreover, about the image development residue, after image development, the presence or absence of the residue of a curable resin composition was evaluated by visual observation.

(5) Adhesiveness of photo spacer The presence or absence of defects in the formed photo spacer was visually observed and evaluated according to the following criteria.
○: No defect and very good adhesion △: Partial defect but good adhesion ×: All defects and poor adhesion

(6) Compression ratio of photo spacer The compression ratio of the photo spacer was measured using a micro compression tester (trade name: HM2000, manufactured by Fisher Instruments). With a 100 μm square planar indenter, the load speed and unloading speed are both set to 4.7 mN / sec., A load of up to 80 mN is loaded and then unloaded to 0.49 mN. A load-deformation curve at the time was created. At this time, the amount of deformation at a load of 80 mN at the time of loading was L1, and the compression rate was calculated by the following formula.
Compression rate (%) = L1 × 100 / spacer height

(7) Elastic recovery rate of photo spacer The elastic recovery rate of the photo spacer was measured using a micro compression tester (trade name: HM2000, manufactured by Fisher Instruments). With a 100 μm square planar indenter, the load speed and unloading speed are both set to 4.7 mN / sec., A load of up to 80 mN is loaded and then unloaded to 0.49 mN. A load-deformation curve at the time was created. At this time, the amount of deformation at a load of 80 mN during loading was L1, and the amount of deformation at a load of 0.49 mN during unloading was L2, and the elastic recovery rate was calculated by the following equation.
Elastic recovery rate (%) = (L1-L2) × 100 / L1

(8) Fracture strength of the photo spacer The break strength of the photo spacer was measured using a micro compression tester (trade name: HM2000, manufactured by Fisher Instruments). With a 100 μm square planar indenter, the load speed and the unloading speed were both set to 4.7 mN / sec, a load up to 300 mN was applied, and the load when the spacer was broken was read from the load-deformation curve.

(9) Thickness (diameter of horizontal cross section) and height of photo spacer The diameter and height of the photo spacer were measured using a laser microscope (trade name “VK-9700”, manufactured by Keyence Corporation).

[Example A-1]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 20 g of benzylmaleimide (BzMI), 44.5 g of acrylic acid (AA), 1 mol ethoxylated phenylphenol acrylate (trade name “HRD-01”, manufactured by Nippon Distillation Co., Ltd. 35.5 g, also referred to as HRD-01), t-butyl peroxy-2-ethylhexanoate (trade name “Perbutyl (registered trademark) O”, manufactured by NOF Corporation, hereinafter also referred to as PBO), 2 g, propylene glycol methyl ether 42 g of acetate (PGMEA) and 18 g of propylene glycol monomethyl ether (PGME) were added and mixed with stirring. Further, 2.0 g of dodecyl mercaptan (nDM), 18 g of PGMEA and 8 g of PGMEA were added as a chain transfer agent solution into the chain transfer agent dropping tank and mixed with stirring.

  The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 7/93 (v / v) mixed gas was started.

  Next, 69 g of glycidyl methacrylate (GMA) in the reaction vessel, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and dimethylbenzyl as a catalyst Amine (DMBA) 0.5 g, PGMEA 16 g and PGME 6 g were charged and reacted at 110 ° C. for 1 hour and 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-1) containing 39.1 weight% of acrylic resins (alkali-soluble resin). The weight average molecular weight (Mw) of the acrylic resin was 17600, and the acid value was 55 mgKOH / g. The production conditions, solid content concentration, weight average molecular weight (Mw) and acid value of the copolymer solution are shown in Table 1 together with Example A-2 to Example A-8, Comparative Example A-9 and Comparative Example A-10. Shown in

[Example A-2]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 30 g of BzMI, 44.5 g of AA, 25.5 g of HRD-01, 2 g of PBO, 42 g of PGMEA, and 18 g of PGME were added as a monomer composition to the monomer dropping tank and mixed with stirring. Further, 2.0 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.

  The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 7/93 (v / v) mixed gas was started.

  Next, 69 g of GMA, 0.3 g of topanol as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME were charged in a reaction vessel and reacted at 110 ° C. for 1 hour and 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-2) containing 39.2 weight% of acrylic resin (alkali-soluble resin). The weight average molecular weight (Mw) of the acrylic resin was 17300, and the acid value was 54 mgKOH / g.

[Example A-3]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 30 g of BzMI, 49 g of AA, 21 g of HRD-01, 2 g of PBO, 42 g of PGMEA and 18 g of PGME were added as a monomer composition into the monomer dropping tank and mixed with stirring. Further, 2.0 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.

  The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 7/93 (v / v) mixed gas was started.

  Next, 69 g of GMA, 0.3 g of topanol as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME were charged in a reaction vessel and reacted at 110 ° C. for 1 hour and 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-3) containing 39.0 weight% of acrylic resins (alkali-soluble resin). The weight average molecular weight (Mw) of the acrylic resin was 17900, and the acid value was 75 mgKOH / g.

[Example A-4]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 30 g of BzMI, 42 g of AA, 28 g of HRD-01, 2 g of PBO, 42 g of PGMEA and 18 g of PGME were added as a monomer composition into the monomer dropping tank and mixed with stirring. Further, 2.0 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.

  The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 7/93 (v / v) mixed gas was started.

  Next, 69 g of GMA, 0.3 g of topanol as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME were charged in a reaction vessel and reacted at 110 ° C. for 1 hour and 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-4) containing 39.2 weight% of acrylic resin (alkali-soluble resin). The weight average molecular weight (Mw) of the acrylic resin was 17100, and the acid value was 45 mgKOH / g.

[Example A-5]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 30 g of BzMI, 44.5 g of AA, 25.5 g of HRD-01, 1.8 g of PBO, 42 g of PGMEA, and 18 g of PGME were added as a monomer composition to the monomer dropping tank and mixed with stirring. Moreover, nDM0.5g, PGMEA18g, and PGMEA8g were thrown into the chain transfer agent dripping tank as a chain transfer agent solution, and it stirred and mixed.

  The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 7/93 (v / v) mixed gas was started.

  Next, 69 g of GMA, 0.3 g of topanol as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME were charged in a reaction vessel and reacted at 110 ° C. for 1 hour and 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-5) containing 39.5 weight% of acrylic resins (alkali-soluble resin). The weight average molecular weight (Mw) of the acrylic resin was 24000, and the acid value was 54 mgKOH / g.

[Example A-6]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 30 g of BzMI, 44.5 g of AA, 25.5 g of HRD-01, 2 g of PBO, 42 g of PGMEA, and 18 g of PGME were added as a monomer composition to the monomer dropping tank and mixed with stirring. Moreover, nDM3.0g, PGMEA18g, and PGMEA8g were thrown into the chain transfer agent dripping tank as a chain transfer agent solution, and it stirred and mixed.

  The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 7/93 (v / v) mixed gas was started.

  Next, 69 g of GMA, 0.3 g of topanol as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME were charged in a reaction vessel and reacted at 110 ° C. for 1 hour and 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-6) containing 38.8 weight% of acrylic resin (alkali-soluble resin). The weight average molecular weight (Mw) of the acrylic resin was 13500, and the acid value was 54 mgKOH / g.

[Example A-7]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, in the monomer dropping tank, BzMI 30 g, AA 44.5 g, HRD-01 23.5 g, methoxypolyethylene glycol (400) acrylate (trade name “light acrylate 130A”, manufactured by Kyoeisha Chemical Co., Ltd., ethylene oxide mole) 2 g, PBO 2 g, PGMEA 42 g and PGME 18 g were added and mixed with stirring. Further, 2.0 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.

  The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 7/93 (v / v) mixed gas was started.

  Next, 69 g of GMA, 0.3 g of topanol as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME were charged in a reaction vessel and reacted at 110 ° C. for 1 hour and 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-7) containing 39.4 weight% of acrylic resin (alkali-soluble resin). The weight average molecular weight (Mw) of the acrylic resin was 17500, and the acid value was 55 mgKOH / g.

[Example A-8]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 30 g of BzMI, 23 g of AA, 47 g of HRD-01, 2 g of PBO, 42 g of PGMEA, and 18 g of PGME were added as a monomer composition into the monomer dropping tank and mixed with stirring. Further, 1.5 g of nDM, 18 g of PGMEA, and 8 g of PGMEA were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.

  The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 7/93 (v / v) mixed gas was started.

  Next, 30 g of GMA, 0.3 g of topanol as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME were charged in a reaction vessel and reacted at 110 ° C. for 1 hour and 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-8) containing 35.1 weight% of acrylic resins (alkali-soluble resin). The weight average molecular weight (Mw) of the acrylic resin was 16900, and the acid value was 56 mgKOH / g.

[Comparative Example A-9]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 15 g of BzMI, 44.5 g of AA, 40.5 g of HRD-01, 2 g of PBO, 42 g of PGMEA, and 18 g of PGME were added as a monomer composition into the monomer dropping tank and mixed with stirring. Further, 2.0 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.

  The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 7/93 (v / v) mixed gas was started.

  Next, 69 g of GMA, 0.3 g of topanol as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME were charged in a reaction vessel and reacted at 110 ° C. for 1 hour and 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-9) containing 39.1 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 17500, and the acid value was 54 mgKOH / g.

[Comparative Example A-10]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 15 g of BzMI, 44.5 g of AA, 38.5 g of HRD-01, 130 A2 g, 2 g of PBO, 42 g of PGMEA, and 18 g of PGMEA were added as a monomer composition to the monomer dropping tank and mixed with stirring. Further, 2.0 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.

  The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 7/93 (v / v) mixed gas was started.

  Next, 69 g of GMA, 0.3 g of topanol, and DMBA 0.5 g, PGMEA 16 g, and PGME 6 g were charged in a reaction vessel, and reacted at 110 ° C. for 1 hour and 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-10) containing 39.4 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 17500, and the acid value was 55 mgKOH / g.

[Example 1]
51 g of the copolymer solution (A-1) (that is, 20 g of acrylic resin), 80 g of tripentaerythritol octaacrylate (trade name “Biscoat # 802”, manufactured by Osaka Organic Chemical Co., Ltd.) as a polyfunctional monomer, and photopolymerization start As an agent, 1.7 g of 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one [trade name “IRGACURE (registered trademark) 907”, manufactured by BASF Japan Ltd.] and a UV absorber As a mixture of 0.5 g of 2- (2-hydroxy-4-octoxyphenyl) -2H-benzotriazole (trade name “SEESORB707” manufactured by Cypro Kasei Co., Ltd., hereinafter referred to as SB707), the solid content concentration becomes 35% by weight. As described above, PGMEA was added and filtered through a filter having a pore diameter of 0.5 μm to prepare a curable resin composition.

The curable resin composition was applied onto a 10 cm square glass substrate with a spin coater and dried in an oven at 90 ° C. for 3 minutes. After drying, the strength (50 mJ / cm ² ) by a UV aligner (trade name “TME-150RNS”, manufactured by TOPCON) with a photomask placed at a distance of 100 μm from the coating film and equipped with a 2.0 kW super high pressure mercury lamp. Ultraviolet rays were irradiated at 365 nm illuminance conversion). After UV irradiation, a 0.05% potassium hydroxide aqueous solution is sprayed on the coating film for 20 to 90 seconds with a spin developing machine to dissolve and remove unexposed portions, and the remaining exposed portions are washed with pure water for 10 seconds. This was developed to form a cylindrical photospacer. At this time, the shortest development time (break time) in which a spacer can be formed and the presence or absence of a development residue were confirmed [Evaluation (4)], and the obtained photospacer was subjected to the above evaluations (5) to (9). The results are shown in Table 2.

[Examples 2 to 18]
Except that the composition of the curable resin composition was changed to the composition shown in Table 2, a photospacer was formed in the same manner as in Example 1 and subjected to the same evaluation as in Example 1. The results are shown in Table 2.
In Table 2, dipentaerythritol hexaacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) is represented as “DPHA”, and pentaerythritol tetraacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) is represented as “PETA”.
Regarding the UV absorber, in Table 2, the trade name “Tinuvin 479” manufactured by BASF Japan Ltd. is expressed as “T479”.

[Comparative Examples 1-2]
Except that the composition of the curable resin composition was changed to the composition shown in Table 3, a photospacer was formed in the same manner as in Example 1 and subjected to the same evaluation as in Example 1. The results are shown in Table 3.

  As shown in Table 2 and Table 3, the content of (b) a monomer capable of introducing a ring structure into the main chain [benzyl maleimide (BzMI) in the examples] is the total monomer component used for synthesizing the base polymer. By using a curable resin composition containing a specific alkali-soluble resin that is 20% by mass or more in 100% by mass and the weight average molecular weight is 40000 or less, the developability is improved without causing development residue. A photo spacer having excellent adhesion could be formed. In the comparative example, the break time was 70 or more. However, in the example, it was confirmed that the break time was significantly improved as 25 to 55, and a remarkable effect was obtained in developability.

  Further, by comparing Examples 1 to 17 and Example 18, in Examples 1 to 17 in the range of (alkali-soluble resin) / (polyfunctional monomer) = 40/60 to 10/90, the development time is shortened. At the same time, it was found that the elastic recovery rate of the obtained photospacer was more excellent. In Examples 1 to 17, a specific effect was obtained that the development time (break time) can be shortened even if the amount of the polyfunctional monomer is increased in order to improve the elastic recovery rate.

  The alkali-soluble resin of the present invention and the curable resin composition containing the alkali-soluble resin can be suitably used for manufacturing a spacer of a liquid crystal cell. It can also be used as a material for color filters, overcoats, insulating films, protective films and the like. Furthermore, it can also be used as a photocurable paint or photocurable ink.

10, 20 Photo spacer

Claims (8)

A base polymer synthesized from a monomer component containing (a) a monomer capable of introducing an acid group into the side chain and (b) a monomer capable of introducing a maleimide structure or an N-substituted maleimide structure into the main chain, or the base An alkali-soluble resin that is a polymer obtained by introducing a carbon-carbon double bond into a polymer,
The content of the monomer capable of introducing a maleimide structure or an N-substituted maleimide structure into the main chain (b) in the monomer component is 20% by mass or more in 100% by mass of the monomer component,
An alkali-soluble resin having a weight average molecular weight of 40000 or less. The amount (BU) of the monomer capable of introducing a maleimide structure or an N-substituted maleimide structure into the main chain (b) is compared to the amount of monomer used (AU) capable of introducing an acid group into the side chain (a). In mass ratio, BU / AU = 0.40 or more.
The alkali-soluble resin according to claim 1. The alkali-soluble resin according to claim 1 or 2, wherein the monomer component further comprises (c) a monomer having an oxyalkylene group and capable of introducing two or more aromatic rings at the end of the side chain. A curable resin composition comprising the alkali-soluble resin according to any one of claims 1 to 3 and a polyfunctional monomer. The content ratio of the alkali-soluble resin and the polyfunctional monomer satisfies the following (Formula 1) in terms of mass ratio.
The curable resin composition according to claim 4.
(Alkali-soluble resin) / (Polyfunctional monomer) = 40/60 to 10/90 (Formula 1)   A cured product obtained by curing the curable resin composition according to claim 4.   A photospacer comprising the cured product according to claim 6. A display device comprising the photospacer according to claim 7.