cover film

Abstract

The present invention provides a cover film having a support and a polymer layer, which can suppress mass reduction and peeling at the bonding site between the cover film and the adherend when a laminate of the cover film and the adherend is stored for a long period of time. The cover film of the present invention is a cover film having a support and a polymer layer containing a polymer, the surface haze of the cover film is 0.5 to 50%, and the content of an ester compound satisfying prescribed requirement 1 in the support is 1% by mass or less relative to the total mass of the support.

Description

Technical Field

[0001] This invention relates to a covering film. Background Technology

[0002] In the medical fields of cell diagnosis and tissue diagnosis, methods for observing microscopic specimens using a microscope are known. One method for preparing such microscopic specimens is as follows: Using an automated sealing device, a cover film having a polymer (e.g., an adhesive or a compound that can act as an adhesive) pre-formed on a support is automatically overlapped onto a substrate (e.g., a glass slide) containing a few drops of a solvent (hereinafter also referred to as a "sealing solution," e.g., xylene) that can swell and / or dissolve the polymer, and the substrate on which the specimen is placed, thereby bonding the cover film to the substrate (hereinafter also referred to as "sealing"). This method allows for the preparation of microscopic specimens in which the specimen is fixed between the substrate and the cover film.

[0003] For example, Patent Document 1 discloses a microscope cover film consisting of a support containing a specified amount of plasticizer and an adhesive layer formed on the support. It is placed to cover the subject on a glass slide and is fixed to the glass slide by swelling or dissolving the adhesive layer with an encapsulating liquid.

[0004] Previous technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2008-003506 Summary of the Invention

[0007] The technical problem to be solved by the invention

[0008] As disclosed in Patent Document 1, the support of existing cover films having a support and a polymer layer sometimes contains ester compounds, represented by phosphate esters, which contribute to the plasticization of the support and the polymer layer.

[0009] It is known that when a cover film containing this ester compound is stored in a high-temperature and high-humidity environment, the ester compound hydrolyzes to generate hydrolysates with low pK values. The components constituting the support decompose through these hydrolysates, reducing the mass of the cover film and causing it to become brittle. Therefore, it is necessary to reduce the amount of the aforementioned ester compound used in the support of the cover film.

[0010] On the other hand, it was found that if the amount of the aforementioned ester compound used is reduced, peeling may sometimes occur between the cover film and the laminated material when they are stored for a long period of time.

[0011] In view of the above-mentioned actual situation, the object of the present invention is to provide a cover film having a support and a polymer layer, the cover film being able to suppress the reduction of the cover film's mass and, when the laminate with the substrate is stored for a long period of time, being able to suppress the peeling of the adhesive portion between the cover film and the substrate.

[0012] means for solving technical problems

[0013] As a result of in-depth research on the above-mentioned issues, the inventors discovered that the above-mentioned issues can be solved according to the following structure.

[0014] [1] A cover film having a support and a polymer layer containing a polymer, wherein the surface haze of the cover film is 0.5 to 50%, and the content of the ester compound satisfying requirement 1 in the support is less than 1% by mass relative to the total mass of the support.

[0015] Requirement 1: The pKa of at least one of the hydrolysates of the above-mentioned ester compounds is 2.5 or less.

[0016] [2] According to the covering film of [1], the surface roughness Rz of the surface of the polymer layer on the side opposite to the support is 0.1 to 30 μm.

[0017] [3] According to the covering film described in [1] or [2], the average length RSm of the roughness curve element of the surface of the polymer layer on the side opposite to the support is 5 to 500 μm.

[0018] [4] The covering film according to any one of [1] to [3], wherein the internal haze of the covering film is less than 1%.

[0019] [5] The covering film according to any one of [1] to [4], wherein the content of the ester compound is 0.6% by mass or less relative to the total mass of the support.

[0020] [6] The covering film according to any one of [1] to [4], wherein the polymer layer comprises a plasticizer.

[0021] [7] The covering film according to any one of [1] to [6] is used to cover the test subject on the substrate.

[0022] Invention Effects

[0023] According to the present invention, a cover film having a support and a polymer layer can be provided, the cover film being able to suppress mass reduction of the cover film and suppress peeling of the adhesive portion between the cover film and the substrate when the laminate is stored for a long period of time. Detailed Implementation

[0024] The present invention will now be described in detail.

[0025] Furthermore, the description of the necessary conditions for the construction involved in the embodiments of the present invention is sometimes based on representative embodiments of the present invention, but the present invention is not limited to such embodiments.

[0026] In this specification, the numerical range represented by “~” indicates the range to which the values ​​recorded before and after “~” are included, respectively, as the minimum and maximum values.

[0027] In the numerical ranges described in this specification, the upper or lower limit of a certain numerical range can be replaced with the upper or lower limit of other numerical ranges described in different stages. Furthermore, within the numerical ranges described in this specification, the upper or lower limit of a certain numerical range can also be replaced with the values ​​shown in the embodiments.

[0028] In this specification, a combination of two or more preferred methods is a more preferred method.

[0029] In this specification, when multiple substances corresponding to each component are present in a composition or layer, unless otherwise stated, the amount of each component in the composition or layer refers to the total amount of the multiple substances present in the composition.

[0030] In this specification, "(meth)acrylic acid" is a general term for acrylic acid and methacrylic acid, referring to "one or more of acrylic acid and methacrylic acid". Similarly, "(meth)acrylate" refers to "one or more of acrylate and methacrylate".

[0031] In this specification, unless otherwise stated, the refractive index refers to the refractive index relative to a wavelength of 550 nm as measured using an Abbe refractometer (manufactured by ATAGO CO.,LTD., “NAR-2T”).

[0032] In this specification, unless otherwise stated, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) are obtained as follows: using a gel permeation chromatography (GPC) analysis apparatus with TSKgel GMHxL, TSKgel G4000HxL, TSKgel G2000HxL and / or TSKgelSuper HZM-N (all trade names manufactured by Tosoh Corporation) columns, with THF (tetrahydrofuran) as solvent, detected by a differential refractometer, and with polystyrene as a standard substance.

[0033] In this specification, the acid dissociation constant (pKa) refers to the pKa in aqueous solution, specifically the value obtained by calculation using the software package described below, based on a database of Hammett substituent constants and known literature values.

[0034] Package 1: Advanced Chemistry Development (ACD / Labs) Software V8.14 for Solaris (1994-2007 ACD / Labs).

[0035] On the other hand, pKa can also be determined using molecular orbital calculations. A more specific method is to calculate the H+ in an aqueous solution based on thermodynamic cycles. + The method of calculating H is based on the dissociation free energy. + Methods for calculating the dissociation free energy include, for example, DFT (density functional theory), but various other methods have been reported in the literature and are not limited to this. Furthermore, several software programs exist capable of performing DFT, such as Gaussian16.

[0036] As stated above, pKa in this specification refers to the value obtained by using software package 1 by calculating a database of substituent constants based on Hammett and known literature values. However, if pKa cannot be calculated by this method, the value obtained by Gaussian16 based on DFT (density functional theory) is used.

[0037] Furthermore, as mentioned above, pKa in this specification refers to "pKa in aqueous solution," but in cases where pKa in aqueous solution cannot be calculated, "pKa in dimethyl sulfoxide (DMSO) solution" is used.

[0038] [Covering film]

[0039] The cover film of the present invention has a support and a polymer layer comprising a polymer. Furthermore, the surface haze of the cover film of the present invention is 0.5% to 50%, and the content of the ester compound satisfying requirement 1 in the support of the cover film of the present invention is 1% by mass or less relative to the total mass of the support.

[0040] Requirement 1: The acid dissociation constant (pKa) of at least one hydrolysate of the ester compound is 2.5 or less.

[0041] Hereinafter, ester compounds that satisfy requirement 1, in which at least one of the hydrolysates generated by hydrolysis has a pKa of 2.5 or less, are also referred to as "specific ester compounds".

[0042] The detailed mechanism by which the cover film of the present invention has the excellent effect of suppressing the loss of the cover film's mass and suppressing the peeling of the adhesive portion between the cover film and the adhesive when the laminate with the substrate is stored for a long time is not necessarily clear, but the inventors speculate as follows.

[0043] First, by keeping the content of a specific ester compound below a specified amount, even under high humidity and high temperature environments, it is possible to suppress the formation of compounds with low pKa that contribute to the decomposition of the support structure contained in the cover film. Furthermore, it is speculated that by keeping the surface haze of the cover film within a specified range, it is possible to produce a cover film with improved adhesion to the substrate, thereby suppressing peeling from the adhesive surfaces during long-term storage.

[0044] In this specification, "effects of the invention" refers to at least one of the effects of suppressing the reduction of the mass of the cover film and suppressing the peeling of the adhesive portion between the cover film and the laminate when the laminate with the laminate is stored for a long period of time.

[0045] [Surface Haze]

[0046] The surface haze of the covering film of the present invention is characterized by 0.5% to 50%.

[0047] When the surface haze of the cover film is 0.5% or higher, the sealing liquid spreads easily on the surface when bonded to the substrate using an sealing liquid, and the polymer layer swells and / or dissolves more uniformly, thus improving the adhesion between the cover film surface and the substrate. Furthermore, when the surface haze of the cover film is 50% or lower, air bubbles can be suppressed at the bonding area between the cover film and the substrate, and peeling of the bonding area after prolonged storage can be prevented.

[0048] Based on the above viewpoint, the surface haze of the covering film is preferably 0.7-40%, more preferably 0.9-30%, and even more preferably 1.0-20%.

[0049] The surface haze of the cover film can be determined by measuring the overall haze and internal haze of the cover film using a haze meter (e.g., “HGM-2DP”, manufactured by Suga Test Instruments Co., Ltd.) according to JIS K-6714, and then subtracting the internal haze from the overall haze.

[0050] The detailed method for measuring the surface haze of the covering film is described in the examples described later.

[0051] As a method for adjusting the surface haze of the cover film, for example, one method can be to control the surface structure of the polymer layer on the side opposite to the support.

[0052] Regarding the surface structure of the polymer layer, for example, in a method (described later) of forming a polymer layer by coating a polymer-containing liquid onto the surface of a support and then drying the coating film, the surface structure can be controlled by adjusting manufacturing conditions such as the viscosity of the coating liquid, the heating conditions during the drying process, the thickness of the coating film, the surface tension gradient of the coating liquid, and the drying conditions. As a specific example, the surface structure of the polymer layer can be controlled by changing at least one of the following: changing the gas concentration of the drying air during the initial stage of coating drying, or changing the temperature and number of heating rollers disposed on the surface of the support opposite to the surface where the coating layer is formed, in the process of bringing the heating rollers into contact.

[0053] Furthermore, as a method for controlling the surface structure of the polymer layer, the following method can be cited: pressing a embossing roller with an embossed surface onto a polymer layer or a coating containing a polymer formed on the surface of a support, so as to transfer an embossed shape onto the polymer layer or the coating.

[0054] The methods for adjusting the surface haze of the covering film are not limited to those described above.

[0055] The structure of the covering membrane will be described below.

[0056] [Support]

[0057] The material constituting the support of the covering film is not particularly restricted as long as the content of a specific ester compound is less than 1% by mass relative to the total mass of the support, and known materials can be used.

[0058] Materials constituting the support include, for example, cellulose polymers such as cellulose triacetate (TAC), cellulose diacetate, cellulose acetate propionate, and cellulose acetate butyrate; polyester polymers such as aliphatic polyesters; polyolefin polymers such as cyclic olefin polymers (COP), polyethylene, and polypropylene; acrylic resins; polycarbonate (PC); and polystyrene, preferably cellulose polymers, acrylic resins, or cyclic olefin polymers (COP), and more preferably cellulose triacetate (TAC).

[0059] When the material constituting the support is a polymer, its weight-average molecular weight (Mw) is, for example, 10,000 to 1,000,000, preferably 30,000 to 300,000.

[0060] The support can use one of the above materials alone, or two or more materials.

[0061] The content of the aforementioned material in the support is preferably greater than 50% by mass relative to the total mass of the support, more preferably 80% by mass or more. The upper limit is not particularly limited; if the support does not contain a specific ester compound, it may be less than 100% by mass relative to the total mass of the support; if the support contains a specific ester compound, it may be the remainder.

[0062] <Specific ester compounds>

[0063] The support of the covering film of the present invention is characterized in that the content of a specific ester compound is less than 1% by mass relative to the total mass of the support.

[0064] That is, the support contains less than 1% by mass relative to the total mass of the support, whether it does not contain a specific ester compound or contains a specific ester compound.

[0065] A specific ester compound is an ester compound obtained by the condensation reaction of an oxyacid of an organic acid or inorganic acid with a hydroxyl-containing compound, wherein the pKa of at least one of the hydrolysate, namely the oxyacid of an organic acid or inorganic acid and a compound having a hydroxyl group, is 2.5 or less.

[0066] Furthermore, in the presence of multiple ester compounds with pKa values, if any one of the multiple pKa values ​​is 2.5 or less, then the ester compound satisfies requirement 1.

[0067] Examples of specific ester compounds include, for example, phosphate esters, phosphites, sulfonates, and nitrates.

[0068] Examples of hydrolysates of specific ester compounds with a pKa of 2.5 or less include phosphoric acid generated by the hydrolysis of phosphate ester compounds, phosphorous acid generated by the hydrolysis of phosphite ester compounds, sulfonic acids such as methanesulfonic acid and benzenesulfonic acid generated by the hydrolysis of sulfonate ester compounds, and nitric acid generated by the hydrolysis of nitrate ester compounds.

[0069] Examples of phosphate ester compounds include, for example, triphenyl phosphate, biphenyl diphenyl phosphate, bisphenol A bis-(diphenyl phosphate), trimethyl phosphate, triethyl phosphate, diphenyl-2-methylacryloyl ethyl phosphate, tricresyl phosphate, tri(xyl) phosphate and toluene diphenyl phosphate.

[0070] Examples of phosphite compounds include, for example, triphenyl phosphite, biphenyl diphenyl phosphite, bisphenol A bis-(diphenyl phosphite), trimethyl phosphite, triethyl phosphite, diphenyl-2-methylacryloyl ethyl phosphite, tricresyl phosphite, tri(xyl) phosphite, and toluene diphenyl phosphite.

[0071] Examples of sulfonate compounds include, for example, methyl benzenesulfonate, ethyl benzenesulfonate, methyl toluenesulfonate, and ethyl toluenesulfonate.

[0072] From the viewpoint that the plasticizing effect is better when transferred to the polymer layer, the preferred ester compound is a phosphate ester compound, more preferably a triphenyl phosphate, a biphenyl diphenyl phosphate, or a tricresyl phosphate, and even more preferably a triphenyl phosphate or a biphenyl diphenyl phosphate.

[0073] When the support contains a specific ester compound, the specific ester compound may be a single compound or two or more compounds. When two or more specific ester compounds are present, the total content of the specific ester compounds relative to the total mass of the support is less than 1% by mass.

[0074] From the viewpoint of further enhancing the effects of the present invention, when the support contains a specific ester compound, the content of the specific ester compound relative to the total mass of the support is preferably 0.6% by mass or less, more preferably 0.4% by mass or less. The support may not contain the specific ester compound, and the content of the specific ester compound in the support may be 0% by mass. The support is particularly preferably free of the specific ester compound.

[0075] The content of specific ester compounds contained in the support can be determined by the following assay method.

[0076] For example, the types and amounts of ester compounds contained in the support are determined using known methods such as gas chromatography-mass spectrometry (GC / MS). Based on the structural formula of the ester compounds, the pKa of the hydrolysates formed by the hydrolysis of each ester compound contained in the support is calculated. In the presence of hydrolysates with a pKa of 2.5 or less, the amount of the ester compounds formed from these hydrolysates (or the total amount if two or more exist) is the amount of the specific ester compound. In the absence of hydrolysates with a pKa of 2.5 or less (i.e., below the detection limit), the support does not contain the specific ester compound.

[0077] <Second Ester Compound>

[0078] The support may contain a second ester compound in addition to a specific ester compound.

[0079] As the second ester compound, there are no particular restrictions if the pKa of the hydrolysate is greater than 2.5. For example, carboxylic acid esters composed of carboxylic acids and hydroxyl-containing compounds can be cited.

[0080] Examples of carboxylic acid ester compounds include, for instance, sugar ester compounds, and carboxylic acid ester oligomers (hereinafter also referred to as "carboxylic acid oligomer A") consisting of dicarboxylic acids having two carboxyl groups and diols having two hydroxyl groups.

[0081] (glycoester compounds)

[0082] Sugar esters are compounds made by replacing some or all of the hydrogen atoms in the hydroxyl groups of sugars with acyl groups.

[0083] Examples of sugars include monosaccharides, disaccharides, and polysaccharides, with disaccharides being preferred.

[0084] Examples of monosaccharides include pentoses such as ribose, deoxyribose, arabinose, and xylose; hexoses such as glucose, galactose, and fructose; and triose, tetroose, and heptose.

[0085] Examples of disaccharides include sucrose, lactose, maltose, trehalose, maltodextrose, and cellobiose, with sucrose being preferred.

[0086] Examples of polysaccharides include glycogen and starch.

[0087] Sugars can have either a chain-like or a cyclic structure. Examples of cyclic structures found in sugars include furanose rings and pyranose rings.

[0088] Examples of aliphatic acyl groups such as formyl, acetyl, propionyl, 2-methylpropionyl, 2,2-dimethylpropionyl, and 2-ethylhexanoyl; and aromatic acyl groups such as benzoyl, 1-naphthylcarbonyl, 2-naphthylcarbonyl, and 2-furanylcarbonyl.

[0089] The number of carbon atoms in the acyl group is preferably 1 to 10.

[0090] As a sugar ester compound, it is more preferably a sugar ester compound represented by the following general formulas (I) to (III).

[0091] (I)(HO)mG-(LR 1 )n

[0092] (II)(HO)pG-(LR 1 )q

[0093] (III)(HO)t-G'-(L'-R 2 )r

[0094] (In general formulas (I) to (III), G and G' independently represent monosaccharide residues or disaccharide residues, respectively. R 1 Each group can be independently represented by an aliphatic group or an aromatic group, with at least one group representing an aromatic group. R 2Each of these groups independently represents an aliphatic group. L and L' independently represent divalent linking groups. m represents an integer greater than or equal to 0, n, p, and q independently represent integers greater than or equal to 1, r represents an integer greater than or equal to 3, and t represents an integer greater than or equal to 0. However, m+n≥4, p+q≥4, m>p, n<q. Furthermore, m+n and p+q are equal in number to the hydroxyl counts of unsubstituted sugars with a cyclic acetal structure having the same backbone as the aforementioned G, which is not a residue, and r+t is equal in number to the hydroxyl counts of unsubstituted sugars with a cyclic acetal structure having the same backbone as the aforementioned G', which is not a residue.

[0095] As sugar ester compounds, more preferably are aromatic sugar ester compounds represented by the above general formula (I), ester compounds represented by the above general formula (II) with a different degree of substitution than aromatic sugar ester compounds represented by the above general formula (I), and sugar ester compound mixtures formed by mixing aliphatic sugar ester compounds represented by the above general formula (III).

[0096] Hereinafter, preferred ranges that are common to all sugar ester compounds and preferred ranges specific to each sugar ester compound that satisfy general formulas (I) to (III) will be described.

[0097] Each sugar ester compound used in the above-mentioned sugar ester compound mixture uses monosaccharide residues or disaccharide residues as its backbone. That is, in the above general formulas (I) to (III), G and G' independently represent monosaccharide residues or disaccharide residues, respectively.

[0098] The aforementioned sugar ester compounds refer to compounds in which at least one substituted group (e.g., hydroxyl, carboxyl) in the sugar backbone structure constituting the compound is bonded to at least one substituent ester. That is, the sugar ester compounds described herein also include sugar derivatives in a broader sense, for example, compounds containing sugar residues such as gluconic acid as structural components. Specifically, the aforementioned sugar ester compounds also include ester bodies of glucose and carboxylic acids, as well as ester bodies of gluconic acid and alcohols.

[0099] The aforementioned sugar ester compounds preferably have a furanose structure or a pyranose structure. When a furanose structure or a pyranose structure is used as the sugar backbone, the following conditions are satisfied in the above general formulas (I) to (III): m+n≥4, p+q≥4, and r is 3 or more.

[0100] Furthermore, when the sugar backbone has a furanose or pyranose structure, the following conditions are also met: the number of hydroxyl groups in m+n and p+q is equal to the number of hydroxyl groups in unsubstituted sugars with a cyclic acetal structure that is assumed to have the same backbone as the above-mentioned G, which is not a residue; and the number of hydroxyl groups in r+t is equal to the number of hydroxyl groups in unsubstituted sugars with a cyclic acetal structure that is assumed to have the same backbone as the above-mentioned G', which is not a residue.

[0101] In addition, the upper limits of m+n, p+q and r+t can be determined according to the type of G or G' mentioned above. If G or G' is a monosaccharide residue, it becomes 5, and if it is a disaccharide residue, it becomes 8.

[0102] As the sugar ester compounds represented by the above general formulas (I) to (III), preferably esterified compounds formed by esterifying all or part of the OH groups in the above-mentioned compound (A) having a furanose structure or a pyranose structure as a monosaccharide residue of G or G', or esterified compounds formed by esterifying all or part of the OH groups in the above-mentioned compound (B) having a disaccharide residue of G or G' bonded to at least two furanose structures or pyranose structures.

[0103] Examples of compounds (A) include glucose, galactose, mannose, fructose, xylose, and arabinose, but are not limited to these.

[0104] Examples of compound (B) include lactose, sucrose, fructotetraose, 1F-fructopentose, stachyose, maltitol, lactitol, lactulose, cellobiose, maltose, cellotriose, maltotriose, metriose, and fructotriose. In addition, examples include gentiobiose, gentiotriose, gentiotetraose, xylitol, and galactosylsucrose, but the list is not limited to these.

[0105] Among these compounds (A) and (B), compounds having both furanose and pyranose structures are particularly preferred. For example, sucrose, fructotriose, fructotetraose, 1F-fructopentose, or stachyose are preferred, with sucrose being more preferred. Furthermore, in compound (B), compounds formed by bonding at least one furanose structure or two pyranose structures are also a preferred embodiment.

[0106] The substituent used for esterifying all or part of the OH groups in compounds (A) and (B) is not particularly limited. A monocarboxylic acid is preferred. That is, the R group in general formula (I) and general formula (II) described above... 1 and the R mentioned in the above general formula (III) 2 It is preferable to represent the acyl group separately and independently.

[0107] There are no particular limitations on the aforementioned monocarboxylic acids; known aliphatic, alicyclic, and aromatic monocarboxylic acids can be used. The carboxylic acid used can be one type or a mixture of two or more. In the presence of multiple R... 1 Or the above R 2 In this case, they can be the same as each other, or they can be different.

[0108] On the other hand, the L in general formula (I) and general formula (II) and the L' in general formula (III) preferably represent single bonds, -O-, -CO-, and -NR, respectively. 11 -(R 11 (representing any one of the substituents with a valence of 1), and in the presence of multiple of the above L... 1 In the case of L' mentioned above, they can be the same as each other or different. Among them, from the above R... 1 and R 2 Based on the view that it can be easily substituted by an acyl group, the above L 1 Or the above L' is preferably represented as -O-.

[0109] Next, preferred embodiments of aromatic sugar ester compounds represented by the above general formulas (I) and (II) will be described.

[0110] In the above general formulas (I) and (II), the above R 1 Each group can independently represent an aliphatic group or an aromatic group, with at least one group representing an aromatic group. Wherein, the above R... 1 Preferably, each and every aromatic group is represented independently; more preferably, all of them are the same aromatic group.

[0111] Furthermore, in the above general formulas (I) and (II), m represents an integer greater than or equal to 0, n, p and q each independently represent an integer greater than or equal to 1, m > p, n < q.

[0112] In the aromatic sugar ester compounds represented by the above general formula (I) and the aromatic sugar ester compounds represented by the above general formula (II), when G is a disaccharide residue, n is preferably 3 or more, and more preferably 5 or more.

[0113] As in R 1 Examples of preferred aromatic monocarboxylic acids used in substitution include benzoic acid, methylbenzoic acid, and other aromatic monocarboxylic acids in which an alkyl or alkoxy group is introduced into the benzene ring of benzoic acid; cinnamic acid; benzyl acid, biphenyl carboxylic acid, naphtholic acid, tetrahydronaphtholic acid, and other aromatic monocarboxylic acids having two or more benzene rings; and their derivatives.

[0114] Next, a preferred embodiment of the aliphatic glycol ester compound represented by the above general formula (III) will be described. In the above general formula (III), the above R 2 Each aliphatic group can be represented independently.

[0115] As a result of R 2Preferred aliphatic monocarboxylic acids used for substitution include saturated fatty acids such as acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, 2-ethylhexanecarboxylic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, hexacosanoic acid, mordanic acid, beeswax acid, and lacquer wax acid; and unsaturated fatty acids such as undecenoic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, and octenic acid.

[0116] Examples of preferred alicyclic monocarboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, or their derivatives.

[0117] The above R 2 Preferably, each R represents an acyclic aliphatic group independently. 2 Preferably, it represents a non-cyclic aliphatic group.

[0118] The above R 2 Preferably, it represents two or more aliphatic groups.

[0119] In aliphatic monocarboxylic acids, the aliphatic glycol ester compound represented by the above general formula (III) is preferably substituted with at least acetic acid. That is, the R in the above general formula (III) 2 At least one of them preferably represents an acetyl group.

[0120] On the other hand, the more preferred option is the aforementioned R. 2 At least one of the above-mentioned R represents a branched aliphatic group, particularly preferably in the form of a branched aliphatic group. 2 When two or more aliphatic groups are represented, only one represents a branched aliphatic group. Preferably, the aliphatic sugar ester compound represented by the above general formula (III) is substituted with isobutyric acid in addition to acetic acid. That is, the R in the above general formula (III) is... 2 Preferably, it contains acetyl and isobutyryl groups.

[0121] From the viewpoint of improving the planar defects of the obtained cellulose ester film, the above-mentioned G' in general formula (III) preferably represents a disaccharide residue.

[0122] Methods for manufacturing aliphatic sugar ester compounds substituted with these aliphatic monocarboxylic acids are, for example, described in Japanese Patent Application Publication No. 8-245678.

[0123] When using a combination of sugar ester compounds represented by the above general formulas (I) to (III) as sugar ester compounds, the mixing ratio is not particularly limited, but the total content of aromatic sugar ester compounds / the content of aliphatic ester compounds (mass ratio) is preferably greater than 1, more preferably 2 to 10, and even more preferably 3 to 5.

[0124] Furthermore, when using a combination of sugar ester compounds represented by the above general formulas (I) to (III) as sugar ester compounds, the total content of the sugar ester compounds represented by the above general formulas (I) to (III) is preferably 1 to 30% by mass relative to the cellulose ester, more preferably 5 to 30% by mass, even more preferably 5 to 20% by mass, and particularly preferably 5 to 15% by mass.

[0125] Regarding the sugar ester compounds represented by the above general formulas (I) to (III), reference can also be made to the description in paragraphs

[0015] to

[0056] of Japanese Patent Application Publication No. 2012-031313, which is incorporated herein by reference.

[0126] (Oligomer A)

[0127] As oligomer A, if it is a compound obtained by condensing a dicarboxylic acid with a diol compound, there are no particular restrictions. For example, compounds having repeating units represented by the following general formula (1) can be cited.

[0128] [Chemical Formula 1]

[0129]

[0130] In general formula (1), X and Y represent divalent linking groups.

[0131] Examples of X include alkylene groups, polyoxyalkylene groups, alkenyl groups, phenylene groups, naphthylene groups, or divalent heterocyclic aromatic groups having 2 to 20 carbon atoms that may have substituents. The alkylene groups among the aforementioned alkylene groups, alkenyl groups, and polyoxyalkylene groups may have an alicyclic structure.

[0132] Examples of Y include alkylene groups, polyoxyalkylene groups, alkenyl groups, phenylene groups, naphthylene groups, or divalent heterocyclic aromatic groups having 2 to 20 carbon atoms and possessing substituents. The alkylene groups among the aforementioned alkylene, alkenyl, and polyoxyalkylene groups may have an alicyclic structure.

[0133] The divalent linking groups represented by X and Y can contain atoms other than carbon atoms, such as oxygen and nitrogen atoms.

[0134] Furthermore, when oligomer A has multiple repeating units represented by general formula (1), X and Y can be the same or different.

[0135] In the repeating unit represented by general formula (1), X preferably represents a non-cyclic divalent linking group with 2 to 10 carbon atoms, and Y preferably represents a divalent linking group with 3 to 12 carbon atoms comprising an alicyclic structure of 3 to 6 members. The alicyclic structure is more preferably a 5-membered ring or a 6-membered ring.

[0136] As oligomer A, it is preferably a compound comprising repeating units represented by general formula (1A) and having its ends capped.

[0137] [Chemical Formula 2]

[0138]

[0139] In general formula (1A), X represents a non-cyclic divalent linking group having 2 to 10 carbon atoms. R represents an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alkynyl group having 2 to 8 carbon atoms, or an aryl group having 6 carbon atoms. m represents an integer from 0 to 4.

[0140] X represents a non-cyclic, divalent linker with 2 to 10 carbon atoms.

[0141] X is preferably a non-cyclic divalent linking group with 2 to 6 carbon atoms, and more preferably a non-cyclic divalent linking group with 2 to 4 carbon atoms.

[0142] Examples of non-cyclic divalent linking groups having 2 to 10 carbon atoms include alkylene groups (preferably having 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, and even more preferably 2 to 4 carbon atoms), ynylene groups (preferably having 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, and even more preferably 2 to 4 carbon atoms), as well as the aforementioned alkylene groups and ynylene groups having heteroatoms (e.g., oxygen atoms and nitrogen atoms).

[0143] Acyclic divalent linking groups with 2 to 10 carbon atoms can have substituents.

[0144] Examples of substituents mentioned above include alkyl, alkoxy, hydroxyl, carboxyl groups, and groups formed by combining them. Acyclic refers to a group that does not contain a cyclic structure. Examples of groups that do not contain a cyclic structure include linear or branched groups.

[0145] R represents an alkyl group with 1 to 8 carbon atoms, an alkenyl group with 2 to 8 carbon atoms, an alkynyl group with 2 to 8 carbon atoms, or an aryl group with 6 carbon atoms.

[0146] Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, propyl, butyl, isobutyl, pentyl, hexyl, octyl, and 2-ethylhexyl, with alkyl groups having 1 to 4 carbon atoms being preferred, and methyl or ethyl being more preferred.

[0147] Examples of alkenyl groups having 2 to 8 carbon atoms include vinyl, 1-methylvinyl, 1-propenyl, 2-propenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, and 2-methylenebutyl.

[0148] Examples of alkynyl groups with 2 to 8 carbon atoms include ethynyl, 1-methylethynyl, 1-propynyl, 2-propynyl, 2-methyl-1-propynyl, 2-methyl-2-propynyl, and 2-methylenebutylyl.

[0149] Examples of aryl groups with 6 carbon atoms include phenyl and 4-methylphenyl.

[0150] The group represented by R may have substituents. For example, examples of substituents that X may have can be cited as substituents.

[0151] Furthermore, the number of carbon atoms in the group represented by R does not include the number of carbon atoms of the substituents that the group represented by R may have. Specifically, aryl groups with 6 carbon atoms include phenyl and 4-methylphenyl.

[0152] R can form a ring structure. Examples of such ring structures include cyclohexyl, cyclooctyl, borneol, isoborneol, and norborneol.

[0153] m represents an integer from 0 to 4. Preferably, m is an integer from 1 to 4, more preferably an integer from 1 to 2, and even more preferably 1.

[0154] Furthermore, the number of repeating units represented by the above general formula (1A) is, for example, an integer from 2 to 60, preferably an integer from 3 to 20, and more preferably an integer from 4 to 10.

[0155] Compounds containing repeating units represented by the above general formula (1A) are preferably end-capped, having a terminal structure derived from a monohydric alcohol or a monocarboxylic acid. For example, when an ester oligomer with a carboxyl group at the end is obtained by reacting a diester compound with a diol compound, the end can be capped with a monohydric alcohol residue by reacting it with a monohydric alcohol. Similarly, when an ester oligomer with a hydroxyl group at the end is obtained, the end can be capped with a monocarboxylic acid residue by reacting it with a monocarboxylic acid.

[0156] The residue represents a portion of the structure of oligomer A and has the characteristics of the monomer that forms the aforementioned terminal structure. For example, the monocarboxylic acid residue formed from monocarboxylic acid R-COOH is R-CO-, and the monohydric alcohol residue formed from monohydric alcohol R-OH is RO-.

[0157] Compounds containing repeating units represented by the above general formula (1A) are preferably terminally capped with an acyl group, more preferably having a terminal structure derived from a monocarboxylic acid. In this case, the terminal structure capped with the acyl group can be linear or branched, or it can have an alicyclic structure. The acyl group is preferably a linear or branched aliphatic acyl group with 2 to 4 carbon atoms, or an alicyclic acyl group with 4 to 12 carbon atoms, more preferably a linear or branched aliphatic acyl group with 2 to 3 carbon atoms, or an alicyclic acyl group with 4 to 7 carbon atoms, and even more preferably a linear or branched aliphatic acyl group with 2 carbon atoms, or an alicyclic acyl group with 7 carbon atoms.

[0158] As a compound containing a repeating unit represented by the above general formula (1A), for example, the description in paragraphs

[0024] to

[0035] of Japanese Patent Application Publication No. 2015-227955 can be cited, and these contents are incorporated into this specification.

[0159] The number average molecular weight (Mw) of oligomer A is preferably 500 to 10,000, more preferably 700 to 3,000, and even more preferably 800 to 1,500.

[0160] The support may contain the aforementioned glycoester compound and a second ester compound other than oligomer A.

[0161] Examples of glycolipid compounds and second ester compounds other than oligomer A include, for example, dioctyl adipate, dibutyl adipate and diisobutyl adipate, etc., diethyl adipate, etc., sebacate, etc., dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dipentyl phthalate, dihexyl phthalate and dicyclohexyl phthalate, etc., diphthalates, tri(2-ethylhexyl) trimellitate, dibutyl maleate, and triacetylglycerol.

[0162] When the support contains a second ester compound, the second ester compound can be a single compound or two or more compounds.

[0163] When the support contains a second ester compound, the content of the second ester compound relative to the total mass of the support is preferably 1 to 30% by mass, more preferably 5 to 15% by mass.

[0164] The content of the second ester compound can be determined according to the method described as a method for determining the content of a specific ester compound.

[0165] <Properties of the support>

[0166] The thickness of the support is not particularly limited, but is preferably 50 to 250 μm, more preferably 50 to 150 μm, and even more preferably 100 to 150 μm.

[0167] Furthermore, the refractive index of the support is not particularly limited; for example, it can be 1.440 to 1.600, and from the viewpoint of visibility when laminated with the substrate, it is preferably 1.460 to 1.560, which is close to that of the glass slide (refractive index 1.52 to 1.56).

[0168] The support can be subjected to surface treatments such as ultraviolet irradiation, corona discharge, or glow discharge.

[0169] [Polymer Layer]

[0170] The covering film has a polymer layer containing a polymer.

[0171] <Polymer>

[0172] The polymer constituting the polymer layer is not particularly limited, but it is preferably swollen in an organic solvent used in the automatic sealing device, and more preferably dissolved in the aforementioned organic solvent. Examples of organic solvents used in the automatic sealing device include xylene, toluene, mesitylene (1,3,5-trimethylbenzene), pseudocumene (1,2,4-trimethylbenzene), thiobenzene (1,2,3-trimethylbenzene), dulene (1,2,4,5-tetramethylbenzene), 3-methylbutyl acetate, anisole, ethyl propionate, amyl acetate, propyl acetate, isopropyl acetate, butyl acetate, methyl lactate, dimethyl carbonate, 1-butanol, 1 The polymer is swollen or dissolved in any one of the following organic solvents: propanol, 2-butanol, 1-pentanol, 2-pentanol, isopentanol, tert-pentanol, neopentanol, cyclopentanol, 2-hexanol, 4-methyl-2-pentanol, methyl isobutyl ketone, acetylacetone, cyclopentanone, n-butyl ether, 1,2-dimethoxyethane, dioxane, cyclocyclopentylmethyl ether, 1-methoxy-2-propanol, propylene glycol methyl ether acetate, ethyl acetate, methyl acetate, acetone, and methyl ethyl ketone, or a mixture of two or more of these solvents. The polymer is swollen or dissolved in the aforementioned organic solvents, thereby bonding the cover film to the substrate (forming an adhesive site) and sealing it into the test subject.

[0173] From the viewpoint of excellent solubility in the aforementioned organic solvents, acrylic resins are preferred as polymers.

[0174] In this specification, acrylic resin refers to a polymer having repeating units derived from acrylate monomers and / or methacrylate monomers.

[0175] As an acrylic resin, if it has repeating units derived from acrylate monomers and / or methacrylate monomers, it is not particularly limited and can be a homopolymer of one monomer selected from the group consisting of acrylate monomers and methacrylate monomers, or a copolymer of two or more monomers selected from the group consisting of acrylate monomers and methacrylate monomers. Furthermore, the acrylic resin can be a copolymer of one or more monomers selected from the group consisting of acrylate monomers and methacrylate monomers with one or more monomers other than acrylate monomers and methacrylate monomers (e.g., acrylamide monomers such as dimethacrylamide and isopropylacrylamide, and vinyl monomers such as styrene).

[0176] In acrylic resins, the content of repeating units derived from acrylate monomers and / or methacrylate monomers is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, relative to all repeating units of the acrylic resin. The upper limit of the content of repeating units derived from acrylate monomers and / or methacrylate monomers is not particularly limited and can be 100% by mass relative to all repeating units of the acrylic resin.

[0177] As an acrylic resin, it is particularly preferred to have only repeating units derived from acrylate monomers and / or methacrylate monomers.

[0178] Acrylic resins can be prepared by known methods, for example, by recombination of one or more monomers selected from the group consisting of acrylate monomers and methacrylate monomers.

[0179] Examples of acrylate monomers and methacrylate monomers mentioned above include alkyl acrylates and alkyl methacrylates.

[0180] The alkyl group in alkyl acrylates and alkyl methacrylates may also have substituents. Examples of such substituents include aryl groups, with phenyl groups being preferred. The number of carbon atoms in the alkyl group that may have substituents in alkyl acrylates and alkyl methacrylates is preferably 1 to 15, more preferably 1 to 8, further preferably 1 to 5, and especially preferably 1 to 3.

[0181] Specific examples of the aforementioned alkyl acrylate monomers include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, lauryl acrylate, phenyl acrylate, benzyl acrylate, 2-methoxyethyl methacrylate, hydroxyethyl acrylate, and acetylacetoxyalkyl acrylate.

[0182] Specific examples of the aforementioned alkyl methacrylate monomers include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, lauryl methacrylate, 2-methoxyethyl methacrylate, hydroxyethyl methacrylate, and acetylacetoxyalkyl methacrylate.

[0183] As a polymer, examples include polymers comprising repeating units derived from one or more monomers selected from the group consisting of alkyl acrylates, alkyl methacrylates, styrene, and acrylamide.

[0184] The meanings of the aforementioned alkyl acrylates and alkyl methacrylates are the same as those already explained.

[0185] The polymer preferably comprises repeating units derived from one or more monomers selected from the group consisting of ethyl acrylate, n-butyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, lauryl methacrylate, 2-methoxyethyl methacrylate, acetyl acetyl methacrylate, styrene, and dimethacrylamide. More preferably, it comprises repeating units derived from one or more monomers selected from the group consisting of ethyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, benzyl methacrylate, lauryl methacrylate, and 2-methoxyethyl methacrylate. More preferably, it comprises repeating units derived from one or more monomers selected from the group consisting of ethyl acrylate and ethyl methacrylate.

[0186] From the viewpoint of further suppressing chips during cutting, the polymer constituting the polymer layer is preferably an acrylic resin composed of a combination of repeating units derived from the aforementioned alkyl acrylate and repeating units derived from the aforementioned alkyl methacrylate. The content of repeating units derived from alkyl acrylate and the content of repeating units derived from alkyl methacrylate in this acrylic resin are preferably 20 to 80% by mass, more preferably 30 to 70% by mass, respectively, relative to all repeating units of the acrylic resin.

[0187] The weight-average molecular weight (Mw) of the polymer is preferably 10,000 to 500,000, more preferably 50,000 to 140,000, and even more preferably 60,000 to 120,000.

[0188] Regarding the covering film of the present invention, when used as a covering film for stained specimens, the staining pigment spreads within the polymer layer, thereby sometimes reducing observability. To prevent this, it is also preferable to reduce the compatibility between the polymer and the staining pigment.

[0189] The compatibility between the polymer and the dyeing pigment (e.g., eosin) can be determined based on the Hansen solubility parameter distance. For example, the preferred Hansen solubility parameter distance between the polymer and the dyeing pigment is 12.00 MPa. 0.5 The above, more preferably 12.50 MPa 0.5 The above is further preferred to be 13.00 MPa. 0.5 The above applies. There is no upper limit to the distance for the Hansen solubility parameter; for example, the above Hansen solubility parameter distance is 40.00 MPa. 0.5 the following.

[0190] In addition, the Hansen solubility parameters can be calculated using the Y-MB method via HSPiP (Hansen Solubility Parameter in Practice (ver5)).

[0191] The polymer content in the polymer layer is not particularly limited, but is preferably 85% by mass or more, more preferably 90% by mass or more, relative to the total mass of the polymer layer. The upper limit can be 100% by mass or less, preferably 99.99% by mass or less, more preferably 99.95% by mass or less.

[0192] <Additives>

[0193] The polymer layer may contain additives other than the polymers mentioned above.

[0194] Additives that may be included in the polymer layer include, for example, silane coupling agents, inorganic particles, and other thickeners and plasticizers, which will be described later.

[0195] (Silane coupling agents)

[0196] The polymer layer may contain at least one selected from the group consisting of silane coupling agents, their hydrolysates, and their hydrolysates (hereinafter also collectively referred to as "silane coupling agents").

[0197] If the polymer layer contains a silane coupling agent, then even if the cover film of the present invention is stored in roll form, it is less likely to stick between the polymer layer and the back side of the support (the side of the support opposite to the side on which the polymer layer is formed), and its shelf life is better.

[0198] The type of silane coupling agent is not particularly limited, but is preferably a silane coupling agent having two or more different reactive groups in the molecule, at least one of which is a reactive group chemically bonded to an inorganic substance, and at least one of which is a reactive group chemically bonded to an organic material.

[0199] Regarding silane coupling agents, examples include silane coupling agents represented by the following general formula.

[0200] X-Si(R 1 )3

[0201] X represents a group having a reactive group. Examples of reactive groups include vinyl, epoxy, amino, (meth)acrylate, and mercapto groups. More specifically, X can be denoted as R... 2 -L- indicates a group. R 2 The symbol represents a reactive group, and L represents a divalent linking group (preferably an alkylene group that may contain heteroatoms (e.g., oxygen atoms).

[0202] R 1 This indicates a hydrolyzable group. A hydrolyzable group is a group that is directly bonded to Si (silicon atoms) and can undergo hydrolysis and / or condensation reactions. Examples of hydrolyzable groups include alkoxy, halogen, acyloxy, alkenyloxy, and isocyanate groups.

[0203] Silane coupling agents are preferably selected from vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-(methacryloyloxypropyl)trimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl- The silane is selected from one or more of the group consisting of γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-chloropropyltrimethoxysilane, more preferably from one or more of the group consisting of γ-glycidoxypropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane, further preferably from one or more of the group consisting of γ-glycidoxypropyltrimethoxysilane and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, and particularly preferably from γ-glycidoxypropyltrimethoxysilane.

[0204] Hydrolysates of silane coupling agents refer to compounds obtained by hydrolyzing the hydrolyzable groups in the silane coupling agent. Furthermore, the aforementioned hydrolysates can be those in which all hydrolyzable groups are hydrolyzed (complete hydrolysates) or those in which only a portion of the hydrolyzable groups are hydrolyzed (partial hydrolysates). That is, the aforementioned hydrolysates can be complete hydrolysates, partial hydrolysates, or mixtures thereof.

[0205] Furthermore, the hydrolysis condensate of the silane coupling agent refers to a compound obtained by hydrolyzing the hydrolyzable groups in the silane coupling agent and condensing the resulting hydrolysate. Additionally, the aforementioned hydrolysis condensate can be a complete hydrolysis condensate (where all hydrolyzable groups are hydrolyzed and all hydrolysates are condensed) or a partially hydrolysis condensate (where some hydrolyzable groups are hydrolyzed and some hydrolysates are condensed). That is, the aforementioned hydrolysis condensate can be a complete hydrolysis condensate, a partially hydrolysis condensate, or a mixture thereof.

[0206] Furthermore, those skilled in the art will readily understand that the type of silane coupling agent used in the polymer layer is selected based on the type of organic material to be bonded to the glass, i.e., the type of polymer constituting the polymer layer.

[0207] The preferred content of silane coupling agents in the polymer layer is 0.1 mg / m² per unit area. 2 The above, more preferably 5-25 mg / m² 2 .

[0208] Silane coupling agents can be used alone or in combination with two or more.

[0209] The silane coupling agent in the polymer layer can be uniformly distributed throughout the entire polymer layer or non-uniformly distributed on the surface of any main surface of the polymer layer. In the case where the silane coupling agent is non-uniformly distributed on the surface of any main surface of the polymer layer, this surface can be the surface of the polymer layer on the side opposite to the support, or the surface of the polymer layer on the side opposite to the support.

[0210] (Thickener)

[0211] The polymer layer may contain a thickener. The type of thickener contained in the polymer layer is not particularly limited, and examples include polymers such as polysaccharides, cellulose, acrylic acid, polyvinyl alcohol, glycols and terpenes, inorganic particles such as silica particles and titanium dioxide particles, and organic particles composed of polymers such as PMMA. Cellulose acetate (more preferably cellulose acetate butyrate or cellulose acetate phthalate) or silica particles are preferred.

[0212] From the viewpoint of being able to suppress the seepage (migration) of hydrophilic materials from components in contact with polymer layers, the surface of inorganic particles is preferably subjected to hydrophobic treatment.

[0213] The size of inorganic and organic particles is not particularly limited. However, if they are too large, scattering is more likely, sometimes resulting in poor visibility. Therefore, the average secondary particle size (the average particle size of the aggregate of inorganic and organic particles) is preferably 1 μm or less. The lower limit is not particularly limited and can be 1 nm or more. Furthermore, the average secondary particle size of inorganic and organic particles can be measured using dynamic light scattering and a particle size measuring device (manufactured by OTSUKA ELECTRONICS CO.,LTD, "nanoSAQLA").

[0214] Furthermore, from the viewpoint of preventing scattering, the refractive index of the inorganic and organic particles is preferably close to that of the polymer layer. More specifically, the refractive index of the inorganic and organic particles is preferably 1.40 to 1.60.

[0215] (Plasticizer)

[0216] The polymer layer may contain plasticizers. By including plasticizers in the polymer layer, the compatibility between the polymer layer and solvents (such as xylene) can be improved, the dissolution rate of the polymer layer when in contact with solvents can be increased, or the brittleness of the polymer layer can be reduced.

[0217] Plasticizers that may be included in the polymer layer are not particularly limited. Examples include phosphates selected from the group consisting of triphenyl phosphate, bisphenol A bis-(diphenyl phosphate), trimethyl phosphate, triethyl phosphate, and diphenyl-2-methylacryloyl ethyl phosphate; adipates such as dioctyl adipate, dibutyl adipate, and diisobutyl adipate; sebacate such as dioctyl sebacate; phthalates such as diethyl phthalate, di(2-ethylhexyl) phthalate, dioctyl phthalate, dinonyl phthalate, didecyl phthalate, and dodecyl phthalate; tri(2-ethylhexyl) trimellitate; dibutyl maleate; and glyceryl triacetate.

[0218] When the polymer layer contains the above-mentioned additives, the content of each additive is not particularly limited. From the viewpoint of further maximizing the effect of each additive, the content is preferably 0.5% or more, more preferably 1% or more, and even more preferably 3% or more, relative to the total mass of the polymer.

[0219] The upper limit of the content of the above-mentioned additives is not particularly limited. From the viewpoint of the adhesiveness of the polymer layer, it is preferably 20% or less, more preferably 15% or less, and even more preferably 10% or less, relative to the total mass of the polymer.

[0220] <Properties of the polymer layer>

[0221] (thickness)

[0222] The thickness of the polymer layer is not particularly limited, but from the viewpoint of better adhesion to the glass slide, it is preferably 1 μm or more, more preferably 10 μm or more. Furthermore, from the viewpoint of better operability of the cover film, the thickness of the polymer layer is preferably 40 μm or less, more preferably 30 μm or less.

[0223] (Surface structure)

[0224] From the viewpoint of further superior effect of the present invention, the surface roughness Rz of the surface of the polymer layer opposite to the surface of the support (hereinafter also simply referred to as "the surface of the polymer layer") is preferably 0.1 to 50 μm, more preferably 0.1 to 30 μm, and even more preferably 0.5 to 10 μm.

[0225] In this specification, the surface roughness Rz of the polymer layer surface refers to the maximum height Rz of the surface as specified in JIS B0601:2013.

[0226] Furthermore, from the viewpoint that the sealing liquid can easily spread on the surface when it is bonded to the substrate using the sealing liquid, the average length RSm (hereinafter also referred to as "average length RSm of roughness") of the surface roughness curve element of the polymer layer is preferably 3 to 600 μm, more preferably 5 to 500 μm, and even more preferably 10 to 300 μm.

[0227] In this specification, the average length RSm of the surface roughness of the polymer layer refers to the average length RSm of the surface roughness curve element as specified in JIS B0601:2013.

[0228] In addition to the surface structure mentioned above, the surface haze of the cover film can also vary depending on the components contained in the support and polymer layer that make up the cover film, as well as the refractive index of the polymer layer.

[0229] In the cover film, the surface roughness Rz and the average length of the unevenness RSm of the polymer layer surface can be determined by measuring a specified area of ​​the polymer layer surface using a laser microscope (e.g., KEYENCE CORPORATION. "VK-9710") and analyzing the obtained image.

[0230] The surface roughness Rz and the average length of unevenness RSm of the polymer layer of the cover film can be adjusted by controlling the surface structure of the polymer layer surface according to the method described as a method for adjusting the surface haze of the cover film.

[0231] (glass transition temperature (Tg))

[0232] From the viewpoint of improving the brittleness of the film, the glass transition temperature Tg of the polymer layer is preferably below 130°C, and more preferably below 100°C.

[0233] From the viewpoint that the polymer layer is less prone to adhesion to other components due to the reduced viscoelasticity and further improved anti-adhesion properties, the lower limit of the glass transition temperature Tg of the polymer layer is preferably 20°C or higher, more preferably 45°C or higher, and even more preferably 80°C or higher.

[0234] The method for determining the glass transition temperature (Tg) of the polymer layer is described in the examples described later.

[0235] The glass transition temperature Tg of the polymer layer can be adjusted by the type and ratio of polymers that make up the polymer layer.

[0236] [Other layers]

[0237] The cover film may have layers other than the support and polymer layer.

[0238] As another example of a layer, a backing layer can be cited.

[0239] The backing layer is provided on the back of the support (the side opposite to the side where the polymer layer is provided) for purposes such as preventing scratches on the surface of the cover film, more reliably preventing adhesion during storage in extremely high temperature environments, or maintaining the curl balance of the cover film.

[0240] Examples of materials that can be used as backing layers include, for example, synthetic polymers with high glass transition temperatures such as polystyrene and polymethyl methacrylate, as well as gelatin.

[0241] [Properties of the covering film]

[0242] <Thickness of the covering film>

[0243] The thickness of the cover film (the sum of the thickness of the polymer layer and the thickness of the support) is not particularly limited, but from the viewpoint of operability and visibility during microscopic observation, it is preferably 250 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less. Regarding the lower limit, from the viewpoint of operability and sealing performance, such as resistance to bending, it is preferably 50 μm or more.

[0244] <Internal haze (IH), Overall haze (TH)>

[0245] From the viewpoint of providing better visibility during microscopic observation, the internal haze (IH) of the covering film is preferably 5% or less, more preferably 1% or less, and even more preferably 0.3% or less. The lower limit is not particularly limited and can be 0% or more.

[0246] The overall haze (IH) of the covering film is the sum of the surface haze (SH) and the internal haze (IH), preferably 0.5% to 55%, more preferably 0.8% to 40%.

[0247] The internal haze (IH) and overall haze (TH) of the covering film can be measured according to JIS K-6714 using a haze meter (e.g., “HGM-2DP”, manufactured by Suga Test Instruments Co., Ltd.). Details of the measurement methods are described in the examples described later.

[0248] <Delay>

[0249] From the viewpoint of being suitable for observation under a polarized light microscope, the thickness retardation (Rth) of the covering film at a wavelength of 590 nm is preferably -300 to 300 nm, more preferably -100 to 100 nm, and even more preferably greater than -50 nm and less than 50 nm.

[0250] From the viewpoint of being suitable for observation under polarized light microscopy, the in-plane retardation (Re) of the cover film at a wavelength of 590 nm is preferably 600 nm or less, more preferably 400 nm or less, and even more preferably 200 nm or less. Furthermore, the lower limit of the in-plane retardation (Re) is not particularly limited and can be 0 nm.

[0251] In addition, in this specification, the in-plane retardation Re(λ) at wavelength λ and the thickness-direction retardation Rth(λ) at wavelength λ refer to the retardations measured by the following methods. Furthermore, unless otherwise specified, λ is set to 590 nm.

[0252] Re(λ) and Rth(λ) can be calculated using a phase difference measuring device (KOBRA-21WR, manufactured by Oji Scientific Instruments) based on the measured values ​​of the average refractive index ((nx+ny+nz) / 3) and film thickness (d(μm)) at wavelength λ. Details of the measurement method are described in the examples described later.

[0253] [Manufacturing method of the covering film]

[0254] As a method for manufacturing the cover film, there are no particular limitations if the support and polymer layer can be laminated, but it is preferable to provide the polymer layer on the surface of the support.

[0255] The method of applying the polymer layer to the support is not particularly limited, and examples include coating, casting, and transfer by a coating machine or sprayer. Among these, it is preferable to coat the support with a coating liquid prepared by dissolving the polymer in a solvent and then dry the coating film to form the polymer layer.

[0256] The type of solvent used in the coating solution can be selected from the viewpoint of polymer solubility, drying speed or surface tension. Examples include toluene, methyl acetate, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, methyl tert-butyl ether and xylene.

[0257] Furthermore, if a solvent capable of swelling or dissolving the surface of the support is used as the solvent in the coating liquid, it can promote the interfacial mixing of the polymer and the support and improve the adhesion between the polymer layer and the support.

[0258] Based on the above viewpoint, the coating liquid used in the formation of the polymer layer preferably contains a solvent selected from the group consisting of toluene, methyl acetate, ethyl acetate, butyl acetate, acetone and methyl ethyl ketone, and more preferably contains at least one solvent selected from the group consisting of toluene, ethyl acetate and acetone.

[0259] From the viewpoint of easily controlling the surface structure of the polymer layer, it is preferable to use two or more types of solvents with different drying speeds and surface tensions in the formation of the polymer layer, and the viscosity of the coating liquid is preferably 10 to 300 mPa·s, more preferably 20 to 150 mPa·s.

[0260] The viscosity of the coating solution can be adjusted based on the polymer content, the weight-average molecular weight (Mw) of the polymers contained in the coating solution, the type of solvent, and the addition of thickeners.

[0261] After forming a coating film by coating a coating liquid containing the above-mentioned polymer onto a support, it is preferable to dry the obtained coating film to remove the solvent from the coating film.

[0262] Examples of drying processes performed in the drying step include placing the coating film at room temperature (23°C) for a specified time (e.g., natural drying), air drying by blowing gas onto the coating film, heating drying using heating components such as ovens, heating plates, and heating rollers to heat the coating film or support, and combinations thereof. Preferably, at least one of air drying and heating drying is performed as the drying process, and more preferably, air drying and heating drying are combined.

[0263] The temperature of the gas used in the air-assisted drying process is not particularly limited, but is preferably 50–160°C, more preferably 80–140°C. Examples of gases used in the air-assisted drying process include air and nitrogen.

[0264] The temperature for heating and drying by the heating element described above is not particularly limited, but is preferably 50 to 160°C. Furthermore, the heating time is preferably 0.5 to 5 minutes.

[0265] Using an induction heating roller that has been embossed on the surface, the embossing is transferred onto the surface of a polymer layer or a polymer-containing coating formed on the surface of a support, thereby enabling control of the surface structure on the surface of the polymer layer.

[0266] More specifically, examples include methods such as pressing the coating surface with a roller at a surface temperature higher than the coating's Tg, and preferably using a clamping method such as a support roller. Furthermore, the shape of the surface texture can be appropriately adjusted by factors such as the embossing shape, the surface temperature of the induction-heated roller, the pressing pressure, and the contact time.

[0267] The method for forming a polymer layer containing a silane coupling agent is not particularly limited. For example, the following methods can be described: a first method in which a silane coupling agent is pre-added to a coating liquid for forming a polymer layer, a coating liquid containing a polymer and a silane coupling agent is coated on a support, and the coating film is dried to form a polymer layer; a second method in which a coating liquid prepared by dissolving a silane coupling agent in a solvent is coated on the surface of a polymer-containing coating film formed on a support, and the coating film is dried to form a polymer layer; and a third method in which a coating liquid containing a polymer and a coating liquid prepared by dissolving a silane coupling agent in a solvent are simultaneously coated (multilayer coating) on ​​a support, and the coating film is dried to form a polymer layer.

[0268] From the viewpoint of being able to utilize silane coupling agents in small quantities and efficiently, the second or third method described above is preferred. In the polymer layer containing silane coupling agents formed by the second or third method described above, the silane coupling agent tends to be unevenly distributed on the surface of the polymer layer on the side opposite to the support.

[0269] As a solvent for the coating liquid prepared by dissolving silane coupling agents in the solvents used in the second and third methods described above, there are no particular limitations as long as the solvent can dissolve the silane coupling agents. For example, solvents that can dissolve the polymers described above can be cited. Among these, ethyl acetate is preferred from the viewpoint of better adhesion.

[0270] [use]

[0271] The covering film of the present invention can preferably be used as a covering film for covering a subject on a substrate. More preferably, it can be used for preparing specimens for microscopic observation, and even more preferably, it is suitable for microscopes equipped with an automatic sealing device.

[0272] The applications of the cover film of the present invention are not limited to those described above. For example, it can be used for film sealing on a substrate and for underlayer protection based on lamination. Furthermore, the substrate on which the cover film is laminated can be glass or a film-shaped substrate (resin, etc.).

[0273] Example

[0274] The present invention will be described in more detail below with examples. The materials, amounts, proportions, processing contents, and processing order shown in the following examples can be appropriately modified without departing from the spirit of the invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[0275] [Material]

[0276] The materials used in the embodiments and comparative examples were prepared using the following methods.

[0277] <Preparation of Polymer Solutions>

[0278] Polymer solutions A to E are manufactured as coating liquids for forming polymer layers according to the following manufacturing method.

[0279] -Polymer Solution A-

[0280] A mixed solution of 90 parts by mass of ethyl acrylate, 210 parts by mass of methyl methacrylate, 98 parts by mass of toluene, 66 parts by mass of ethyl acetate, and 1.8 parts by mass of azoisobutyronitrile was added to the mixture at 80°C under a nitrogen atmosphere for 2 hours. The resulting mixture was reacted at 80°C for another 2 hours. Then, 1.0 part by mass of azoisobutyronitrile was added to the mixture, and the reaction was carried out at 90°C to generate a polymer with a weight-average molecular weight (Mw) of 80,000. Finally, 111 parts by mass of toluene and 368 parts by mass of ethyl acetate were added to the mixture to obtain polymer solution A containing the polymer.

[0281] The glass transition temperature (Tg) of the polymer layer prepared using polymer solution A is 85°C. The method for determining the glass transition temperature (Tg) of the polymer layer will be described later.

[0282] -Polymer Solution B-

[0283] A mixed solution of 90 parts by mass of ethyl acrylate, 210 parts by mass of methyl methacrylate, 98 parts by mass of toluene, 66 parts by mass of ethyl acetate, and 1.8 parts by mass of azoisobutyronitrile was added to the mixture at 80°C under a nitrogen atmosphere for 2 hours. The resulting mixture was reacted at 80°C for another 2 hours. Then, 1.0 part by mass of azoisobutyronitrile was added to the mixture, and the reaction was carried out at 90°C to generate a polymer with a weight-average molecular weight (Mw) of 70,000. Then, 111 parts by mass of toluene, 368 parts by mass of ethyl acetate, and 3 parts by mass of dinonyl phthalate relative to 100 parts by mass of the generated polymer were added to the mixture to obtain polymer solution B containing the polymer.

[0284] The glass transition temperature (Tg) of the polymer layer made using polymer solution B is 85℃.

[0285] -Polymer solution C-

[0286] Instead of dinonyl phthalate, 15 parts by weight of hydrophobic silica (“NX90S”, surface-treated with hexamethyldisilazane, manufactured by NIPPON AEROSIL CO.,LTD.) with an average primary particle size of 20 nm were used, and polymer solution C containing the polymer was obtained according to the above-described method for manufacturing polymer solution B.

[0287] The glass transition temperature (Tg) of the polymer layer made using polymer solution C is 84℃.

[0288] -Polymer solution D-

[0289] A mixed solution of 60 parts by mass of ethyl acrylate, 180 parts by mass of methyl methacrylate, 60 parts by mass of ethyl methacrylate, 98 parts by mass of toluene, 66 parts by mass of ethyl acetate, and 1.8 parts by mass of azoisobutyronitrile was added to the mixture at 80°C under a nitrogen atmosphere for 2 hours. The resulting mixture was reacted at 80°C for another 2 hours. Then, 1.0 part by mass of azoisobutyronitrile was added to the mixture, and the reaction was carried out at 90°C to generate a polymer with a weight-average molecular weight (Mw) of 100,000. Finally, 111 parts by mass of toluene and 368 parts by mass of ethyl acetate were added to the mixture to obtain polymer solution D containing the polymer.

[0290] The glass transition temperature (Tg) of the polymer layer made using polymer solution D is 97℃.

[0291] -Polymer solution E-

[0292] A mixed solution of 60 parts by mass of ethyl acrylate, 180 parts by mass of methyl methacrylate, 60 parts by mass of butyl methacrylate, 98 parts by mass of toluene, 66 parts by mass of ethyl acetate, and 1.8 parts by mass of azoisobutyronitrile was added to the mixture at 80°C under a nitrogen atmosphere for 2 hours. The resulting mixture was reacted at 80°C for another 2 hours. Then, 1.0 part by mass of azoisobutyronitrile was added to the mixture, and the reaction was carried out at 90°C to generate a polymer with a weight-average molecular weight (Mw) of 100,000. Then, 111 parts by mass of toluene and 368 parts by mass of ethyl acetate were added to obtain a polymer solution E containing the polymer.

[0293] The glass transition temperature (Tg) of the polymer layer made using polymer solution E is 90℃.

[0294] -Polymer solution F-

[0295] A mixture of 38 parts by mass of toluene and 25 parts by mass of ethyl acetate was added to a nitrogen atmosphere at 80°C for 2 hours. This mixture consisted of 75 parts by mass of ethyl acrylate, 150 parts by mass of methyl methacrylate, 75 parts by mass of ethyl methacrylate, 98 parts by mass of toluene, 66 parts by mass of ethyl acetate, and 1.8 parts by mass of azoisobutyronitrile. The resulting mixture was reacted at 80°C for another 2 hours. Then, 1.0 part by mass of azoisobutyronitrile was added to the mixture, and the reaction was carried out at 90°C to generate a polymer with a weight-average molecular weight (Mw) of 100,000. Finally, 111 parts by mass of toluene and 368 parts by mass of ethyl acetate were added to the mixture to obtain a polymer solution F containing the polymer.

[0296] The glass transition temperature (Tg) of the polymer layer made using polymer solution F is 90℃.

[0297] <Coating solution for polymer layer formation>

[0298] Solvents selected from toluene, ethyl acetate and acetone were mixed in the following mixing ratios (mass ratios) to prepare diluents A to C respectively.

[0299] Diluent A: Toluene / Ethyl Acetate = 20 / 80 (mass ratio)

[0300] Diluent B: Toluene / Ethyl Acetate = 25 / 75 (mass ratio)

[0301] Diluent C: Toluene / Ethyl Acetate / Acetone = 20 / 20 / 60 (mass ratio)

[0302] By adding any one of the diluents A to C to the polymer solutions prepared above, coating solutions (coating solutions 1 to 10) for forming polymer layers with specified liquid viscosities are prepared. When the polymer solutions are diluted with the respective diluents, the dilution rate is adjusted so that the liquid viscosity (unit: mPa·s) of each coating solution is as shown in Table 1.

[0303] Table 1 below shows the names of the coating solutions prepared in each embodiment and comparative example, the types of polymer solutions used, the types of diluents, and the liquid viscosity of the prepared coating solutions.

[0304] <Preparation of Silane Coupling Agent Coating Solution>

[0305] To obtain a silane coupling agent coating solution, 0.11 parts by weight of silane coupling agent KBM403 (γ-glycidoxypropyltrimethoxysilane) (Shin-Etsu Chemical Co., Ltd.) were mixed with 109.89 parts by weight of ethyl acetate.

[0306] <Support>

[0307] -Support A1-

[0308] The support A1 is made according to the following method.

[0309] (Preparation of cellulose ester solution A1)

[0310] Place the following ingredients into a mixing vessel and heat and stir simultaneously to dissolve each ingredient, thus preparing cellulose ester solution A1.

[0311] • 100 parts by weight of cellulose ester (acetyl substitution degree 2.86, viscosity average degree of polymerization 310)

[0312] • A sugar ester mixture prepared by mixing the mixture of the following sugar ester compounds (I) and (II) and the following sugar ester compound (III) in a mass ratio of 12:3 (mixture of sugar ester compounds (I) and (II): sugar ester compound (III)).

[0313] 384 parts by weight of dichloromethane

[0314] ·Methanol 69 parts by weight

[0315] ·9 parts by weight of butanol

[0316] The amount of the sugar ester mixture contained in the cellulose ester solution A1 is adjusted so that the content of the sugar ester mixture contained in the support A1 made using the cellulose ester solution A1 (the total content of the sugar ester compounds) is the content recorded in Table 1 below.

[0317] The mixture of the above-mentioned sugar ester compounds (I) and (II) is represented by the above general formulas (I) and (II), where G represents sucrose residues and the substituent LR... 1 It represents a mixture of aromatic sugar ester compounds with benzoyl groups, and is a mixture of sugar ester compounds (I) and (II) with an average degree of substitution (average of n and q) of 5.7.

[0318] Furthermore, the aforementioned sugar ester compound (III) is an aliphatic sugar ester compound, represented by the above general formula (III), where G' represents a sucrose residue and the substituent L'-R 2It represents either acetyl or isobutyryl, and is prepared by replacing an average of two hydroxyl groups of the eight hydroxyl groups of the sucrose residue with acetyl and an average of six hydroxyl groups with isobutyryl.

[0319] (Preparation of matting agent dispersion B1)

[0320] The following components are placed in a disperser and stirred to dissolve them, thereby preparing matting agent dispersion B1.

[0321] • Silica particle dispersion (average particle size 16nm, “AEROSIL R972”, manufactured by NIPPON AEROSIL CO.,LTD.): 10.0 parts by weight

[0322] Dichloromethane: 72.8 parts by weight

[0323] Methanol: 3.9 parts by weight

[0324] Butanol: 0.5 parts by weight

[0325] Cellulose ester solution A1: 10.3 parts by weight

[0326] Add matting agent dispersion B1 to cellulose ester solution A1, and heat the mixture while stirring thoroughly to dissolve the components, thus preparing concentrated solution A1. The mixing ratio of cellulose ester solution A1 and matting agent dispersion B1 is adjusted so that the total content of sugar ester compounds of formulas (I) to (III) contained in the support A1 made using concentrated solution A1 is the content recorded in Table 1 below.

[0327] The obtained concentrated liquid A1 was heated to 30°C and cast through a casting mold onto a 3m diameter mirror stainless steel roller. The surface temperature of the roller was set to -5°C, and the coating width was set to 1470mm. The overall ambient temperature of the casting section was set to 15°C. Then, at a point approximately 50cm from the end of the casting section, the cellulose ester film formed on the roller surface was peeled off from the roller, and the two ends of the peeled cellulose ester film in the width direction were clamped using a pin-plate tenter frame.

[0328] The cellulose ester sheet held by the pin-plate tenter frame is conveyed to the drying zone. Drying air at 45°C is blown out during the initial drying. Then, it is dried by heating at 110°C for 13 minutes, followed by heating at 140°C for 25 minutes, to obtain a support A1 with the thickness shown in Table 1 below.

[0329] Among the hydrolysates of the ester compounds contained in support A1, the lowest pKa is 5.0, which is present in at least one hydrolysate of the aforementioned glycoester compound (III). Therefore, the specific ester compound is not contained in support A1.

[0330] -Support A2-

[0331] The support A2 is made according to the following method.

[0332] (Preparation of concentrated cellulose acylate solution from the core layer)

[0333] The following components are placed in a mixing tank and the mixture is stirred to dissolve the components, thereby preparing a cellulose acetate solution A2a for use as a core layer cellulose acylation concentrate.

[0334] 100 parts by weight of cellulose acetate with a degree of acetyl substitution of 2.88

[0335] • A mixture comprising the aliphatic carboxylic acid ester oligomer (oligomer A1) described below and a compound represented by the following formula (A-3), wherein the mass ratio of oligomer A1 to the compound represented by formula (A-3) is 4:1.

[0336] 430 parts by weight of dichloromethane

[0337] ·Methanol 64 parts by weight

[0338] The amount of the above-mentioned mixture contained in the cellulose ester solution A2a is adjusted such that the total content of polyester A and the compound represented by formula (A-3) contained in the support A2 prepared by the following method using cellulose ester solution A2a and cellulose ester solution A2b described below is the content recorded in Table 1 below.

[0339] [Chemical Formula 3]

[0340]

[0341] Oligomer A1 is an aliphatic carboxylic acid ester oligomer, a condensation product of 1,2-cyclohexyldicarboxylic acid and ethylene glycol, with a terminal structure in which the hydrogen atoms of the two terminal hydroxyl groups are replaced by cyclohexyl groups (terminal capping). The number average molecular weight of oligomer A1 is 850.

[0342] (Preparation of concentrated outer cellulose acylate solution)

[0343] To prepare cellulose acetate solution A2b, which can be used as an outer layer cellulose acylate concentrate, 10 parts by mass of a matting agent solution B2 having the following composition are added to 90 parts by mass of the above cellulose acetate solution A2a (core layer cellulose acylate concentrate).

[0344] [Composition of matting agent solution]

[0345] • 2 parts by weight of silica particles (AEROSIL R972, manufactured by NIPPON AEROSIL CO.,LTD.) with an average particle size of 20 nm.

[0346] 76 parts by weight of dichloromethane

[0347] ·Methanol 11 parts by weight

[0348] · 1 part by mass of cellulose acetate solution A2a (concentrated cellulose acylate from the core layer)

[0349] (Fabrication of support A2)

[0350] The above-mentioned core layer cellulose acylate concentrate and the above-mentioned outer layer cellulose acylate concentrate were filtered using filter paper with an average pore size of 34 μm and a sintered metal filter with an average pore size of 10 μm, respectively. The filtered core layer cellulose acylate concentrate and the filtered outer layer cellulose acylate concentrate were then simultaneously cast from the casting port of a belt casting machine onto the surface of a roller with a surface temperature of 20°C, forming a laminated film in which the core layer is sandwiched between two outer layers.

[0351] Next, the laminated film was peeled off from the rollers, and both ends of the laminated film in the width direction were fixed with tenter frame clamps. The laminated film, fixed with tenter frame clamps, was stretched along the width direction at an elongation ratio of 1.1 times while being dried. Then, the laminated film was further dried by conveying it between the rollers of a heat treatment apparatus to produce a support A2 with the thickness described in Table 1 below.

[0352] Among the hydrolysates of the ester compounds contained in support A2, the lowest pKa is 4.0, which is possessed by at least one hydrolysate of the compound represented by formula (A-3) above. Therefore, support A2 does not contain the specific ester compound.

[0353] -Support A3-

[0354] Except for the absence of the compound represented by formula (A-3) above, support A3 is manufactured according to the method for manufacturing support A2 described above. Support A3 has a laminated structure in which a core layer is sandwiched between two outer layers, and has the thickness described in Table 1 below.

[0355] Among the hydrolysates of the ester compounds contained in support A3, the lowest pKa is 5.0 for the hydrolysate of oligomer A1, 1,2-cyclohexyldicarboxylic acid. Therefore, support A3 does not contain the specific ester compound.

[0356] -Support body A4~A7-

[0357] Instead of the sugar ester compounds represented by formulas (I) to (III) above, a mixture containing triphenyl phosphate and diphenyl phosphate in a mass ratio of 2:1 (triphenyl phosphate: diphenyl biphenyl phosphate) is used, and the amount of the mixture contained in the cellulose ester solution is adjusted so that the total content of the phosphate ester compounds contained in the support made using the cellulose ester solution is the content recorded in Table 1 below. Otherwise, supports A4 to A7 are made according to the method for making support A1 above.

[0358] Triphenyl phosphate and biphenyl diphenyl phosphate are equivalent to specific ester compounds that satisfy requirement 1 because they both generate phosphoric acid with a pKa of 2.0 through hydrolysis.

[0359] However, in supports A4 and A5, the total content of the specific ester compound is less than 1% by mass relative to the total mass of each support. On the other hand, in supports A6 and A7, the total content of the specific ester compound is greater than 1% by mass relative to the total mass of each support.

[0360] -Support B-

[0361] Support B was obtained by film formation using commercially available acrylic resin (DELPET 980N, manufactured by ASAHI KASEI CORPORATION) via a known melt extrusion method. Support B does not contain any specific ester compounds.

[0362] -Support C-

[0363] Support C was obtained by film formation using a commercially available cyclic olefin polymer (“ZEONOR ZF-14”, manufactured by Zeon Corporation) via a known melt extrusion method. Support C did not contain any specific ester compounds.

[0364] -Support D-

[0365] Using commercially available polyester (“MA-8334P”, manufactured by UNITIKA LTD., polyethylene terephthalate), a film is formed by a known melt extrusion method, and the resulting film is biaxially stretched and heat-set to obtain support D. Support D does not contain any specific ester compound.

[0366] [Making of the covering film]

[0367] [Example 1 (Manufacturing Condition A)]

[0368] On the surface of the support A1 prepared by the above method, coating liquid 1 was applied by extrusion coating. The coating amount of coating liquid 1 was adjusted so that the thickness of the dried polymer layer was the value recorded in Table 1 below. After applying coating liquid 1, the resulting coating layer was heated and dried at 100°C for 5 minutes using a hot air dryer, thereby producing the cover film of Example 1.

[0369] [Examples 2-4 (Manufacturing Condition A and Post-processing A), Comparative Example 3 (Manufacturing Condition A and Post-processing B)]

[0370] After using coating liquid 2 instead of coating liquid 1 and heating and drying the coating layer at 100°C for 5 minutes using a hot air dryer, a post-treatment was performed whereby an induction heating roller with a surface temperature of 150°C and an embossed surface was pressed onto the coating layer. Otherwise, the cover films of Examples 2 to 4 were produced according to the method described in Example 1. Furthermore, the surface shape of the coating layer was adjusted by the shape of the embossing on the induction heating roller, thereby adjusting the surface haze of the cover film within the range of 0.5% to 50% (post-treatment A).

[0371] Furthermore, except for using induction heating rollers with different embossing shapes, the cover film of Comparative Example 3 was produced according to the method described in Examples 2 to 4 above. In addition, the surface shape of the coating layer was adjusted by using the embossing shape of the induction heating roller, thereby adjusting the surface haze of the cover film to 51% (post-treatment B).

[0372] [Examples 5-10, 12 and 14-20, Comparative Examples 1, 2 and 4 (Manufacturing Condition A)]

[0373] In addition to using the coating liquid and support described in Table 1 below, the cover films of Examples 5-10, 12 and 14-20, and Comparative Examples 1, 2 and 4 were prepared according to the method described in Example 1 above.

[0374] [Example 11 (Manufacturing Condition B)]

[0375] Coating liquid 7 was applied to the surface of support A2 by extrusion coating. The amount of coating liquid 7 was adjusted so that the thickness of the dried polymer layer was the value described in Table 1 below. In the downstream region of the support in the conveying direction immediately after coating liquid 7 was applied to support A2, a heated roller heated to 65°C was brought into contact with the surface of the support opposite to the surface on which the coating layer was formed, thereby heating the support and the coating layer to dry the coating layer. Then, the coating layer was heated and dried at 100°C for 5 minutes using a hot air dryer to produce the cover film of Example 11.

[0376] [Example 13 (Manufacturing Condition C)]

[0377] Coating liquid 7 and the aforementioned silane coupling agent coating liquid were applied to the surface of support A2 by extrusion multilayer coating. The coating amount of coating liquid 7 was adjusted so that the thickness of the dried polymer layer was the value recorded in Table 1 below. The coating amount of the silane coupling agent coating liquid was 13.5 mg / m² of silane coupling agent relative to the surface area of ​​support A2. 2 The amount. After coating the coating liquid 7 and the silane coupling agent coating liquid, the coating layer is dried at 100°C for 5 minutes to produce the cover film of Example 13.

[0378] [Property determination of the covering film]

[0379] [Surface haze, internal haze]

[0380] The covering films produced in each embodiment and comparative example were cut to a size of 40 mm × 80 mm to obtain film samples. The overall haze (TH) of the film samples was measured using a haze meter (HGM-2DP, manufactured by Suga Test Instruments Co., Ltd.) according to JIS K-6714 at an environment of 25°C and 60% relative humidity, thereby determining the overall haze (TH) of the film samples.

[0381] Next, the film sample was sandwiched between two glass plates using xylene as an indexing liquid to create a laminate. The haze of the resulting laminate was measured in the same manner as described above to determine the internal haze (IH) of the film sample.

[0382] In addition, the difference between the overall haze (TH) and the internal haze (IH) of the membrane sample (TH-IH) is calculated, and the surface haze (SH) of the membrane sample is obtained from this.

[0383] [Surface roughness Rz, average length of unevenness RSm]

[0384] The surface area of ​​the cover film produced in each example was measured using a laser microscope (VK-9710, manufactured by KEYENCE CORPORATION). The surface roughness Rz and the average length of the unevenness RSm of the polymer layer surface were then determined (both units are μm).

[0385] [Delay (Rth)]

[0386] The cover films prepared in each embodiment and comparative example were cut to a size of 50 mm × 50 mm to obtain film samples. After the obtained film samples were conditioned at 25°C and 60% relative humidity for more than 2 hours, the thickness retardation (Rth) of each film sample was measured by incident light with a wavelength of 590 nm on the film sample using a phase difference measuring device (KOBRA-21WR, manufactured by Oji Scientific Instruments).

[0387] [Glass transition temperature (Tg) of the polymer layer]

[0388] The polymer layers were peeled off from each cover film. The obtained polymer layers were cut into 5mm × 30mm sizes to obtain polymer layer samples. After the obtained samples were conditioned at 25°C and 60% relative humidity for more than 2 hours, the peak temperature of the observed loss tangent (loss modulus of elasticity / storage modulus) was measured using a dynamic viscoelasticity measuring device (VIBRON: DVA-225 (manufactured by IT Measurement Control Co., Ltd.)) at a clamping distance of 20mm, a heating rate of 5°C / min, and a frequency of 100Hz. This peak temperature was then used as the glass transition temperature Tg (°C).

[0389] [Evaluation of the covering film]

[0390] [Time-consuming peeling]

[0391] Using the Cover Aid automated sealing device SCA-Film-J0 (SAKURA SEIKI Co., Ltd.), a laminate was fabricated by bonding the cover films prepared in each embodiment and each comparative example to a glass slide. Xylene was used as the sealing solvent.

[0392] Two laminates were prepared for each embodiment and each comparative example. One laminate was placed in an environment of 40°C and 80% relative humidity (condition 1), and the other laminate was placed in an environment of 10°C and 30% relative humidity (condition 2) for 14 days. The accelerated film peeling test was carried out.

[0393] The bonding areas of the laminate after accelerated testing were visually inspected, and the generation and delamination of bubbles at the interface between the substrate and the polymer layer were evaluated according to the following criteria. Furthermore, the presence of bubbles at the interface between the substrate and the polymer layer can be considered as having the same practical application as delamination.

[0394] (Evaluation Criteria)

[0395] 0: No bubbles or peeling were observed under either condition.

[0396] 1: Under any conditions, at least one of the following is observed: slight bubbles and peeling.

[0397] 2: Under both conditions, at least one of the following was observed: slight bubbles and peeling.

[0398] 3: Under any conditions, at least one of the following is observed: a few bubbles and peeling.

[0399] 4: Under both conditions, a small number of bubbles and at least one type of peeling were observed.

[0400] 5: Under at least one of the following conditions, at least one of the following is clearly observed: bubbles and peeling.

[0401] Record the evaluation results in the table. Evaluations of 0-4 are practically sound.

[0402] [Reduced quality]

[0403] Using the Cover Aid automated sealing device SCA-Film-J0 (SAKURA SEIKI Co., Ltd.), the cover films prepared in each embodiment and comparative example were bonded to the glass slides. Xylene was used as the sealing solvent.

[0404] After preparing 20 encapsulated specimens and allowing them to dry thoroughly at room temperature, a total of 20 encapsulated specimens were stacked in such a way that the slide of one encapsulated specimen was in close contact with the support of another encapsulated specimen. Then, an accelerated test was conducted, in which the resulting laminates were stored at 85°C and 85% relative humidity for 500 hours.

[0405] Based on the mass of the laminate measured before and after the accelerated test, the ratio of the difference between the mass of the laminate before and after the accelerated test and the mass of the laminate before the accelerated test [{(mass of the laminate before the accelerated test) - (mass of the laminate after the accelerated test)} / (mass of the laminate before the accelerated test)] (unit: mass%) is calculated as the mass reduction rate based on the accelerated test.

[0406] The mass reduction of the covering film was evaluated according to the following criteria based on the obtained mass reduction rate.

[0407] (Evaluation Criteria)

[0408] 1: The rate of quality reduction is less than 0.1% of mass.

[0409] 2: The mass reduction rate is greater than 0.1% and less than 1%.

[0410] 3: The mass reduction rate is greater than 1% of the mass.

[0411] Record the evaluation results in the table. In the case of evaluation 1 or 2, there are no practical problems.

[0412] Table 1 shows the manufacturing conditions and characteristics of the polymer layer, the characteristics of the support, the physical properties of the cover film, and the evaluation results.

[0413] In the table below, the “Name” column of “Coating Liquid” for “Polymer Layer” indicates the coating liquid for forming the polymer layer used in each embodiment and comparative example; the “Polymer Solution” column and the “Diluent” column indicate the polymer solution and diluent used in each coating liquid; and the “Liquid Viscosity” column indicates the viscosity (unit: mPa·s) of each coating liquid.

[0414] The "Manufacturing Conditions" column under "Manufacturing Process" for "Polymer Layer" indicates the drying method of the coating layer implemented in each embodiment and comparative example. Furthermore, the "Post-treatment" column indicates the post-treatment A or B performed on the dried coating film in Examples 2-4 and Comparative Example 3.

[0415] The "Thickness [μm]" column for "Polymer Layer" and "Support" indicates the thickness (in μm) of the support and polymer layer of the cover film in each embodiment and comparative example.

[0416] In the cases where the support used in each embodiment and comparative example contains an ester compound, the type of ester compound ("Type" column), the minimum pKa value of the hydrolysate of the ester compound ("Decomposition pKa" column), and the total content of the ester compound relative to the total mass of the support (mass %, "Content [%]" column) are shown in the "Ester Compound" column of the "Support" section in the table below.

[0417] The ester compounds shown in the "Types" column above are as follows.

[0418] A: A mixture of the above-mentioned sugar esters (I) to (III)

[0419] B: Oligomer A1 and compounds represented by formula (A-3)

[0420] C: Oligomer A1

[0421] D: Triphenyl phosphate and biphenyl diphenyl phosphate

[0422] In the “Rth(590)[nm]” column of “Covering Film” in the table, “<100” indicates that the thickness direction delay (Rth) of the film sample measured by the above method is greater than 50nm and less than 100nm, and “<50” indicates that the thickness direction delay (Rth) of the film sample measured by the above method is greater than -50nm and less than 50nm.

[0423] [Table 1]

[0424]

[0425] [Table 2]

[0426]

[0427] [Table 3]

[0428]

[0429] The results shown in the table confirm that the cover film of the present invention has superior performance compared with the cover films of Comparative Examples 1 to 4, which have a specific ester compound content greater than 1% by mass relative to the total mass of the support, or a surface haze of less than 0.5% or greater than 50%.

Claims

1. A cover film for microscopic observation, having a support and a polymer layer containing a polymer, The surface haze of the covering film is 0.5% to 30%. The surface haze is calculated by subtracting the internal haze from the overall haze, based on the overall haze and internal haze of the covering film measured using a haze meter according to JIS K-6714. The internal haze of the covering film is less than 1%. The surface roughness Rz of the polymer layer on the side opposite to the support is 0.1–30 μm. The surface roughness Rz refers to the maximum height Rz of the surface as specified in JIS B0601:2013. The average length RSm of the roughness curve element on the side of the polymer layer opposite to the support is 5–500 μm. The average length RSm of the roughness curve element refers to the average length RSm of the surface roughness curve element as specified in JIS B0601:2013. The content of the ester compound satisfying condition 1 in the support is less than 1% by mass relative to the total mass of the support. The polymer content in the polymer layer is 90% by mass or more. Requirement 1: At least one of the hydrolysates of the ester compound has a pKa of 2.5 or less.

2. The microscope observation covering film according to claim 1, wherein, The content of the ester compound is less than 0.6% by mass relative to the total mass of the support.

3. The microscope observation covering film according to claim 1 or 2, wherein, The polymer layer contains a plasticizer.

4. The cover film for microscopic observation according to claim 1 or 2, which is used to cover the subject on a substrate.

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