JP2010107336A - Evaluation method of porous aggregate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To evaluate precisely performance of a porous aggregate by observing directly and nondestructively from the surface up to an internal structure of the porous aggregate formed by aggregating a plurality of components such as fibers or particles. <P>SOLUTION: In this evaluation method of the porous aggregate, a liquid whose refractive index difference from a refractive index of components is below 1 is impregnated into the porous aggregate formed by aggregating the plurality of components, and then observed by a microscope, to thereby confirm existence of a component larger than 0.4 μm. Each size of the components is confirmed by the measuring method, by observing directly and nondestructively up to the internal structure of the porous aggregate formed by aggregating the plurality of components, and the result is reflected to process management or product management when manufacturing the porous aggregate and various materials using the porous aggregate, to thereby enable stable manufacture of a product having a desired quality. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for evaluating a porous assembly, and more specifically, by directly observing a non-destructive structure from the surface of a porous assembly comprising a plurality of components such as fibers and particles to the internal structure. The present invention relates to a method for evaluating the performance of a porous assembly.

  Conventionally, a porous assembly in which a plurality of components are assembled in various fields has been used. For example, filters, non-woven fabrics, woven fabrics, membranes, etc. can be mentioned, but a method for confirming the structure of such a porous assembly, in particular, the interior is established. It wasn't.

  In particular, when this component is a fiber or particle, the inside of the porous assembly is not necessarily a uniform structure. Furthermore, the component, for example, fiber or particle has a fiber diameter or particle size distribution. If there is, the internal structure is expected to be even more uneven. Such an internal structure often affects the performance of the porous assembly, and therefore it is important to establish a method for accurately detecting the internal structure of the porous assembly.

  On the other hand, in recent years, a plastic substrate replacing a glass plate has been studied as a display substrate for liquid crystal, organic EL, and the like. This is because a glass plate has a specific gravity and is difficult to reduce in weight, and it has drawbacks such as being easily broken, not being bent, and requiring a thickness. Specifically, it is a display substrate using polycarbonate, polyethylene terephthalate, or the like. Is used.

However, these conventional plastic materials for glass replacement have a larger coefficient of linear expansion than glass plates, so in the process of depositing a device layer such as a thin film transistor on a substrate at a high temperature, warping, cracking of the deposited film, disconnection of the semiconductor Such problems are likely to occur and practical use is difficult.
That is, a plastic material having high transparency, high heat resistance, low water absorption, and low linear expansion coefficient is required for these uses.

  As a material that can satisfy such required performances, a glass composite plastic composite material having improved transparency by dispersing fibers made of smaller structural units in a resin has been developed. As this smaller structural unit, fibers obtained by refining natural cellulose into nanofibers are preferably used. Since cellulose has an extended chain crystal, it is known to exhibit a low linear expansion coefficient, a high elastic modulus, and a high strength. It has also been reported that fine and highly crystalline cellulose nanofibers can be obtained by miniaturization, and that composite materials having high transparency and low linear expansion can be obtained by filling the gaps between the fibers with a matrix material. There are provided composite materials in which finely divided cellulose fibers are made into porous aggregates such as nonwoven fabrics and the gaps between the fibers are filled with a matrix material.

  However, in the production process of cellulose nanofiber, when obtaining a nano-sized fiber by refining from a raw material having a large fiber diameter (for example, a diameter of several tens to several μm) such as pulp, the fiber diameter is distributed. It is known that the fiber diameter distribution affects the transparency of the obtained composite material. Therefore, it is necessary to confirm or measure the fiber diameter in the composite material and reflect it in the control of transparency.

  However, it is difficult to accurately measure the fiber diameter distribution in the composite material with a general particle size distribution analyzer. Moreover, although it can observe using SEM (scanning electron microscope) and TEM (transmission electron microscope) in the state of the dispersion liquid of the refined cellulose fiber, about porous aggregates, such as a nonwoven fabric, dozens of Even though the surface of about several hundred nm can be observed, it is difficult to confirm or measure the fiber diameter of the fibers in the porous assembly by directly observing the internal structure with SEM or TEM.

In patent document 1, the fineness of a nonwoven fabric is prescribed | regulated by measuring the transmittance | permeability of the light of wavelength 850nm in the state which immersed the nonwoven fabric containing a cellulose in toluene. However, this method can see the correlation with the transparency when the nonwoven fabric and resin are combined, but it only shows the overall trend, and it is a method that can directly observe the distribution of individual fibers. Absent.
JP 2006-316253 A

  As described above, since the structure of a porous assembly composed of components such as fibers and particles often affects the performance of the porous assembly, the structure of the porous assembly may be confirmed. It becomes important. In addition, in the case of a composite material that has been developed in recent years, for example, a composite material in which a matrix material is composited with a porous assembly such as a nonwoven fabric obtained by refining fibers such as cellulose, the viewpoint of its influence on transparency Therefore, it is important to understand the structure of the porous assembly.

  However, in the past, what is the structure of a porous assembly in which a plurality of components used in various fields, for example, a filter, a non-woven fabric, a woven fabric, and a membrane are formed, and in particular how the inside is Until now, no method has been established for confirming whether or not this is the case.

  The present invention has been made in view of the above-described conventional situation, and directly observes non-destructively from the surface of the porous assembly formed by aggregating a plurality of components such as fibers and particles to the internal structure, It is an object of the present invention to provide a method for accurately evaluating the performance of the porous assembly.

As a result of intensive studies to solve the above problems, the present inventors have confirmed that the internal structure of the porous assembly can be observed nondestructively and the size of the component can be confirmed or measured by using a specific method. The headline and the present invention were completed.
That is, the gist of the present invention is as follows.

[1] A porous aggregate in which a plurality of constituent elements are aggregated is impregnated with a liquid having a refractive index difference of 1 or less with respect to the refractive index of the constituent elements. A method for evaluating a porous assembly, wherein the presence or absence of a component is confirmed.

[2] The porous assembly according to [1], wherein the constituent elements are fibers and / or particles, and the presence or absence of fibers having a fiber diameter of 0.4 μm or more and / or particles having a particle diameter of 0.4 μm or more is confirmed. Body evaluation method.

[3] The method for evaluating a porous aggregate according to [1] or [2], wherein the constituent element is a crystalline component.

[4] The method for evaluating a porous aggregate according to any one of [1] to [3], wherein the constituent element is cellulose.

[5] The method for evaluating a porous aggregate according to any one of [1] to [4], which is observed with a polarizing microscope.

[6] The method for evaluating a porous aggregate according to any one of [1] to [5], wherein a constituent element of 0.4 μm or more is confirmed and the size thereof is measured.

[7] The method for evaluating a porous aggregate according to [6], wherein the constituent element is a fiber, and the fiber length and / or the fiber diameter is measured.

[8] The method for evaluating a porous assembly according to [6], wherein the constituent element is a particle, and the particle size thereof is measured.

  According to the present invention, a porous aggregate in which a plurality of constituent elements are aggregated is observed with a microscope in a state in which a liquid having a refractive index difference of 1 or less with respect to the refractive index of the constituent elements is impregnated. Not only the surface of the body but also the internal structure can be directly observed nondestructively, and the presence or absence of components of 0.4 μm or more can be confirmed or the size thereof can be measured.

  Such a method for evaluating a porous aggregate of the present invention is more effective particularly when the constituent element is a fiber and / or particle, and further a crystalline component. The non-destructive observation of the internal structure of the porous assembly in which a plurality of components are aggregated is performed directly to confirm the size of the component, and the results are obtained using the porous assembly and various types of porous assemblies. By reflecting the process management and product management when manufacturing the material, it becomes possible to stably manufacture a product having a desired quality.

  Embodiments of the present invention will be specifically described below, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.

〔Component〕
The present invention relates to a method for evaluating a porous assembly by confirming the presence or absence of a component of a certain size or more in a porous assembly in which a plurality of components are assembled. Although it does not specifically limit about the component which forms the porous aggregate | assembly made into measurement object by this invention, For example, a fiber and particle | grains are mentioned.

Examples of fibers include various types of fibers such as natural fibers such as plant fibers, animal fibers, mineral fibers, and dietary fibers, or synthetic fibers such as synthetic fibers, semi-synthetic fibers, regenerated fibers, glass fibers, and carbon fibers. Can be mentioned.
Of these, crystalline fibers are preferred for measurement. This is because the fibers are clearly visible when measured using a polarizing microscope. Examples of the crystalline fiber include cellulose, mineral fiber, polyester fiber made of crystalline synthetic polymer, polyimide fiber, and the like.

  Although it does not specifically limit as a magnitude | size of a fiber, Usually, length is several tens nm to several cm, and thickness (fiber diameter) is several nm to several mm.

  Examples of the particles include various particles such as inorganic particles such as metal particles and metal oxide particles, organic particles such as polymer particles, and particles obtained by combining them. Among these, crystalline particles are suitable for measurement. The shape of the particle is not particularly limited, and may be various shapes such as a spherical shape, an elliptical spherical shape (rugby ball shape), a cube shape, a rectangular parallelepiped shape, a flake shape (scale shape), and other irregular shapes.

  Although it does not specifically limit as a magnitude | size of particle | grains, Usually, they are several nm to several mm. Here, the particle size (particle size) corresponds to the diameter of a spherical particle, but in the case of a particle of another shape, when the particle is sandwiched between two parallel plates, The dimension of the part where the distance between the plates is the largest.

  The porous assembly according to the present invention may contain one or more of these fibers, may contain one or more of these particles, and In addition, fibers and particles may be included, and other components other than the fibers and particles may be included.

(Porous aggregate)
In the present invention, the porous aggregate refers to an aggregate in which a plurality of components as described above are aggregated. By collecting a plurality of constituent elements, for example, voids are generated between fibers or particles. For example, fibers and particles may contact or bond at points, lines, or surfaces, but when forming an aggregate, it will be an aggregate with pores unless it undergoes large deformation and adheres. Such an aggregate is referred to as a porous aggregate according to the present invention (hereinafter sometimes referred to as “the porous aggregate of the present invention”).

  The size of the pores between the constituent elements in the porous assembly is usually several nm to several mm, although it depends on the size of the constituent elements or the distribution of the sizes and the method of forming the aggregate.

  In addition, the pore structure of the porous assembly also depends on the size of the constituent elements or the distribution of the size, and the formation method of the assembly, but when there are pores in the shape of a straight tunnel in the porous assembly, There are various cases, for example, when there are holes in a winding tunnel, or when the holes are closed and formed into a bowl shape.

  Furthermore, the shape of the porous aggregate is also arbitrary, and examples thereof include a thick structure, a sheet, a film, a film, and a woven fabric and a nonwoven fabric.

[Method for producing porous assembly]
As the porous aggregate of the present invention, for example, there are no particular limitations on the method for producing a structure, a sheet, a membrane, and a film, and it is produced by a general method. In order to make it porous, for example, a technique such as foam molding may be used.

  Among the porous aggregates of the present invention, as a method for producing a nonwoven fabric, a wet process in which fibers as constituent elements are suspended in a solvent such as water, a web is made with a net, desolvated, heated and dried. A dry method in which a raw material is heated, melted, extruded from a nozzle, directly spun, and a web is formed from the eluted endless long fibers;

[Liquid having a refractive index difference of 1 or less with respect to the refractive index of the component]
<Type>
In the present invention, prior to the microscopic observation of the constituent elements in the porous assembly, first, a liquid having a refractive index difference of 1 or less with respect to the refractive index of the constituent elements of the porous assembly (hereinafter referred to as a porous assembly). Impregnated in some cases.

  If the difference between the refractive index of the impregnating liquid and the refractive index of the component exceeds 1, the porous aggregate after impregnation with the impregnating liquid is not transparent, and the internal structure of the porous aggregate cannot be observed with a microscope. . The difference between the refractive index of the impregnating liquid and the refractive index of the constituent elements is preferably as small as possible, and particularly preferably 0.5 or less, particularly 0.3 or less.

  The impregnating liquid used in the present invention can be appropriately selected according to the constituent elements in the porous assembly. For example, when the constituent elements are cellulose fibers, the refractive index of cellulose is 1.6. The refractive index of the liquid is preferably in the range of 0.6 to 2.6, more preferably in the range of 1.1 to 2.1, and further preferably in the range of 1.3 to 1.9. preferable.

  Specific examples of the impregnating liquid include standard refractive liquids, such as oil immersion oil, immersion oil, matching oil, immersion liquid, etc., and those having a wide range of refractive indexes can be obtained and prepared. Examples of the immersion oil include IMMERSION OIL manufactured by CARGILLE LABORATORIES.

<Impregnation method>
The method of impregnating the porous assembly with the impregnating liquid is not particularly limited. For example, the method of immersing the porous assembly in the impregnating liquid, the method of spraying the impregnating liquid onto the porous assembly, Examples thereof include a method of dropping (flowing down) the porous aggregate.

  In addition, it is preferable that the size of the sample used for microscope observation is an appropriate size (for example, 5 mm square to 10 mm square) enough to be placed on a slide glass for microscope observation. Therefore, the porous assembly impregnated with the impregnating liquid is preferable. The body is cut in advance to such a size.

  After impregnating the porous assembly with the impregnating liquid in this way, the porous assembly containing the impregnating liquid is covered with a cover glass, and in this state for 1 hour or longer, preferably 6 hours or longer, more preferably 12 Allow to stand for more than an hour to stabilize the liquid impregnation state. In addition, since the effect beyond it is not acquired even if this leaving time is too long, the upper limit of leaving time is normally 3 days or less, Preferably it is 2 days or less.

  The pressure at the time of this leaving may be a normal pressure or a slightly reduced pressure or a pressurized state. In addition, if the impregnated liquid is volatile, the porous aggregate after stabilization needs to be measured immediately before drying, but if it is not volatile like oil, it can be stored for a long time. is there.

<Curing of impregnating liquid>
In the present invention, after impregnating the porous assembly with the impregnating liquid, the impregnating liquid may be cured by light or heat. As such a curable impregnating liquid, specifically, an acrylate or methacrylate monomer containing a photopolymerization initiator or a thermal polymerization initiator (hereinafter referred to as “(meth) acrylate”. About “(meth) acryl”) And epoxy resin monomers and oxetane resin monomers.

  The photopolymerization initiator may be a compound that generates radicals by light such as ultraviolet rays. For example, one kind of benzophenone, benzoin methyl ether, benzoin propyl ether, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2,6-dimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, or the like Two or more types can be mentioned.

  The thermal polymerization initiator may be any compound that generates radicals by heating. For example, 1 type (s) or 2 or more types, such as a hydroperoxide, a dialkyl peroxide, a peroxy ester, a diacyl peroxide, a peroxy carbonate, a peroxy ketal, a ketone peroxide, are mentioned. Specifically, benzoyl peroxide, diisopropyl peroxy carbonate, t-butyl peroxy (2-ethylhexanoate) dicumyl peroxide, di-t-butyl peroxide, t-butyl peroxybenzoate, t-butyl hydroperoxide Side, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide and the like can be used.

  Examples of the (meth) acrylate monomer include a monofunctional (meth) acrylate compound having one (meth) acryloyl group in the molecule, and two, three or more (meth) acryloyl groups in the molecule. A polyfunctional (meth) acrylate compound, a styrene compound, an acrylic acid derivative, and the like can be given.

  Examples of monofunctional methacrylate compounds having one (meth) acryloyl group in the molecule include methyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, and cyclohexyl. (Meth) acrylate is mentioned.

As polyfunctional (meth) acrylate compounds having 2 or 3 (meth) acryloyl groups in the molecule, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, Polyethylene glycol di (meth) acrylate, tetraethylene glycol or higher, 1,3-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 2-hydroxy 1,3-di (meth) acryloxypropane, 2,2-bis [4- (meth) acryloyloxyphenyl] propane, trimethylolpropane tri (meth) acrylate, bis (hydroxy) tricyclo [5.2.1. 0 ^2,6 Decane = diacrylate, bis (hydroxy) tricyclo [5.2.1.0 ^2,6 ] decane = dimethacrylate, bis (hydroxy) tricyclo [5.2.1.0 ^2,6 ] decane = acrylate methacrylate, Bis (hydroxy) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane = diacrylate, bis (hydroxy) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane = dimethacrylate, bis (hydroxy) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane = acrylate methacrylate, 2,2-bis [4- (β-methacryloyloxyethoxy) phenyl] propane, 2,2-bis [4- (β-methacryloyloxyethoxy) cyclohexyl] propane, 1, 4-bis (methacryloyloxymethyl) cyclohexane and the like can be mentioned.

  As the (meth) acrylate having 3 to 8 (meth) acryloyl groups in the molecule, (meth) acrylic acid ester of polyol can be used. Specifically, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, Dipentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, tripentaerythritol octa (meth) acrylate, tripentaerythritol septa (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tripentaerythritol penta ( (Meth) acrylate, tripentaerythritol tetra (meth) acrylate, tripentaerythritol tri (meth) acrylate, etc. It is.

Examples of the styrene compound include styrene, chlorostyrene, divinylbenzene, and α-methylstyrene.
Examples of (meth) acrylic acid derivatives other than the (meth) acrylic acid ester include acrylamide, methacrylamide, acrylonitrile, methacrylonitrile and the like.

  These may be used alone or in combination of two or more.

  Moreover, when using an epoxy resin monomer or an oxetane resin monomer, a photocationic polymerization initiator that generates an acid by light such as ultraviolet rays is used. This is a compound that initiates cationic polymerization by irradiation of active energy rays such as ultraviolet rays and electron beams. For example, as an aromatic sulfonium salt, bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluorophosphate, bis [4- (Diphenylsulfonio) phenyl] sulfide bishexafluoroantimonate, bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluoroborate, bis [4- (diphenylsulfonio) phenyl] sulfide tetrakis (pentafluoro Phenyl) borate, diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate, diphenyl-4- (phenylthio) phenylsulfonium hexafluoroantimonate, diphenyl-4 (Phenylthio) phenylsulfonium tetrafluoroborate, diphenyl-4- (phenylthio) phenylsulfonium tetrakis (pentafluorophenyl) borate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrafluoro Borate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, bis [4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide bishexafluorophosphate, bis [4- (di (4 -(2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide bishexafluoroantimonate, bis [4- (di (4- (2-hydro) Ciethoxy)) phenylsulfonio) phenyl] sulfide tetrafluoroborate, bis [4- (di (4- (2-hydroxyethoxy)) phenylsulfonylio) phenyl] sulfidetetrakis (pentafluorophenyl) borate, and the like. .

  Aromatic iodonium salts include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium tetrafluorobonate, diphenyliodonium tetrakis (pentafluorophenyl) borate, bis (dodecylphenyl) iodonium hexafluoroantimonate, bis (dodecyl) Phenyl) iodonium tetrakis (pentafluorophenyl) borate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium hexafluorophosphate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium hexafluoroantimonate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium hexafluoroborate 4-methylphenyl-4- (1-methylethyl) phenyl iodonium tetrakis (pentafluorophenyl) borate, and the like.

Examples of the aromatic diazonium salt include phenyldiazonium hexafluorophosphate, phenyldiazonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, and diphenyliodonium tetrakis (pentafluorophenyl) borate.
Examples of aromatic ammonium salts include 1-benzyl-2-cyanopyridinium hexafluorophosphate, 1-benzyl-2-cyanopyridinium hexafluoroantimonate, 1-benzyl-2-cyanopyridinium tetrafluoroborate, 1-benzyl-2- Cyanopyridinium tetrakis (pentafluorophenyl) borate, 1- (naphthylmethyl) -2-cyanopyridinium hexafluorophosphate, 1- (naphthylmethyl) -2-cyanopyridinium hexafluoroantimonate, 1- (naphthylmethyl) -2- Examples thereof include cyanopyridinium tetrafluoroborate and 1- (naphthylmethyl) -2-cyanopyridinium tetrakis (pentafluorophenyl) borate.
Aromatic iron compounds include (2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -iron (II) hexafluorophosphate, (2,4-cyclopentadien-1-yl) [ (1-methylethyl) benzene] -iron (II) hexafluoroantimonate, (2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -iron (II) tetrafluoroborate, (2 , 4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -iron (II) tetrakis (pentafluorophenyl) borate and the like.

  The epoxy resin monomer is a compound having an epoxy ring in the molecule. This is a di- or polyglycidyl ether produced by the reaction of a polyhydric phenol compound or its alkylene oxide adduct and epichlorohydrin, for example, diglycidyl ether of bisphenol A or its alkylene oxide adduct, novolac type epoxy resin Is mentioned. In addition, there are di- or polyglycidyl ethers by reaction of aliphatic polyhydric alcohols or alkylene oxide adducts thereof with epichlorohydrin, such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1 , 4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, cyclohexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, trimethylolpropane diglycidyl ether, trimethylolpropane triglycidyl ether , Pentaerythritol triglycidyl ether, pentaerythritol tetraglycidyl ether Le, sorbitol hepta glycidyl ether, glycol diglycidyl ethers such as sorbitol hexa glycidyl ether.

  As the alicyclic epoxy resin, cyclohexene oxide or cyclopentene oxide obtained by epoxidizing a compound having at least one cyclohexene or cycloalkane such as cyclopentene with an oxidizing agent such as hydrogen peroxide or peracid. Etc. Examples thereof include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate.

The oxetane resin monomer is a compound having oxetane in the molecule, such as 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- (2 -Ethylhexyloxymethyl) oxetane, 3-ethyl {[3- (triethoxylyl) propoxy] methyl} oxetane, 3-ethyl-3-methacryloxymethyloxetane, and the like.
Compounds having two oxetanes in the molecule include di [1-ethyl (3-oxetanyl)] methyl ether, 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, 4 , 4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] biphenyl, and the like. Examples of the compound having 3 to 4 oxetane rings include a branched polyalkyleneoxy group and a reaction product of a polysiloxy group and 3-alkyl-3-methyloxetane.

  These may be used alone or in combination of two or more.

  After impregnating the above-mentioned porous aggregate with these photocurable resins, the resin is cured by a general method using light or heat. In this case, for example, the following method can be used.

  First, a composition in which a polymerizable resin monomer and a photopolymerization initiator are mixed is prepared. The porous assembly is then impregnated with this composition. A general method can be used as the impregnation method. For example, a method of immersing the porous assembly in the composition, a method of spraying the composition on the porous assembly, and the like can be mentioned. The polymerizable resin monomer is polymerized by irradiating the porous aggregate impregnated with the composition in this manner with active energy rays such as ultraviolet rays or heating. Examples of the active energy rays include infrared rays, visible rays, ultraviolet rays, electron beams, and the like, preferably light having a wavelength of about 200 to 450 nm, and more preferably ultraviolet rays having a wavelength of 250 to 400 nm.

The amount of active energy rays to be irradiated is arbitrary as long as the photopolymerization initiator generates radicals and cations, but if it is extremely small, the polymerization becomes incomplete, so the heat resistance and mechanical properties of the cured product are low. If it is not sufficiently expressed and is extremely excessive, on the contrary, the cured product will be deteriorated by light such as yellowing, so that the wavelength of 200 to 450 nm is adjusted according to the composition of the monomer and the type and amount of the photopolymerization initiator. UV, preferably in the range of 0.1~200J / cm ^2, more preferably irradiated with a range of 1~20J / cm ^2.
In this case, it is more preferable to irradiate the active energy rays by dividing them into a plurality of times because the curing becomes uniform. That is, when the first irradiation is performed for about 1/20 to 1/3 of the total irradiation amount and the necessary remaining amount is irradiated for the second and subsequent times, a cured product with smaller birefringence is obtained.
Specific examples of the lamp to be used include a metal halide lamp, a high-pressure mercury lamp lamp, an electrodeless lamp, an ultraviolet LED lamp, and the like.

  As described above, when the porous assembly is impregnated with the impregnating liquid and then cured, the cured product of the impregnating liquid also has a refractive index difference of 1 or less with respect to the refractive index of the porous assembly, preferably It is important that it is 0.5 or less, more preferably 0.3 or less.

[Microscopic observation]
In the present invention, a porous assembly (hereinafter sometimes referred to as “sample”) impregnated with the impregnating liquid as described above and further cured in some cases may be 10 to 40 times magnification with an optical microscope. Observe at. If this observation magnification is too small, components of 0.4 μm or more cannot be observed. If the observation magnification is too large, it is difficult to obtain a clear image.

  This microscopic observation is particularly preferably performed with a polarizing microscope, and by synthesizing photographs taken while rotating under a crossed Nicol condition using a polarizing microscope, the microscopic observation is 0.4 μm or more without depending on the in-plane orientation angle. The component can be observed.

  Here, the “component of 0.4 μm or more” specifically refers to a fiber having a fiber diameter of 0.4 μm or more if the component is a fiber, and may be spherical if the component is a particle. For example, if the diameter is elliptical, the minor axis is cubic. If the cube is a rectangular parallelepiped, the short side is 0.4 μm or more. If it is a shape, it shall be a particle | grain which contains a circle | round | yen with a diameter of 0.4 micrometer in the projection surface of an optical microscope.

[Microscopic observation of components and measurement principle]
The observation and measurement principles of the constituent elements by the method for evaluating a porous assembly of the present invention are as follows.
That is, when impregnating the impregnating liquid with a refractive index difference of 1 or less with respect to the refractive index of the constituent elements in the porous assembly, the scattering of the pores of the porous assembly is eliminated and the impregnation is performed. The entire liquid-impregnated porous assembly becomes transparent. When a sample in such a state is observed with a microscope, not only the surface of the sample but also the internal structure is larger than the wavelength of visible light (0.4 μm) and only components that scatter light of 0.4 μm or more. Can be detected. As described above, since the whole sample in which the porous assembly is impregnated with the impregnating liquid becomes transparent, it is possible to observe the bulk state in which the surface and the inside are combined with a microscope. Here, the observation limit inside the sample depends on the size of the constituent elements of the porous assembly, the resolution of the microscope used, and the focal length. It is considered that even an internal structure of about several tens nm to several tens mm or less, preferably several mm or less, more preferably about 500 μm or less can be observed from the (observation surface side).

[Confirmation and measurement of components and their application]
According to the present invention, as described above, it is possible to grasp the size distribution of the constituent elements in the porous assembly by observing the constituent elements of 0.4 μm or more by microscopic observation of the sample.
For example, if nothing is observed by this method, the porous aggregate does not contain a component of 0.4 μm or more, and consists of components having a size of less than 0.4 μm. It is thought that there are almost no components scattered by

As mentioned above, in recent years, in order to reinforce a transparent material, a composite material in which a porous assembly is impregnated with a resin is often used, but if nothing is observed by the method according to the present invention, the porosity The aggregate does not contain a component of 0.4 μm or more. Therefore, the transparency of the composite material using the porous aggregate is very high, and a material having a low haze can be obtained. On the other hand, when a large number of constituent materials are observed by the method according to the present invention, the porous aggregate contains a large number of constituent elements of 0.4 μm or more, and the transparency of the composite material using the porous aggregate is extremely high. Therefore, it becomes a material having a high haze.
Thus, by using the evaluation method of the present invention, when the porous assembly is applied to a composite material, it is possible to grasp qualitatively or quantitatively the influencing factors on the transparency of the composite material.

Furthermore, by analyzing an image obtained by this measurement method, the shape of a component of 0.4 μm or more can be analyzed. For example, when the component of 0.4 μm or more is fibrous, the fiber length, fiber diameter, or aspect ratio thereof can be measured. When the component is granular, the particle size and its distribution Can be measured.
Specifically, the size and distribution can be measured by picking up and measuring components of 0.4 μm or more from the contrast of the obtained image by image analysis. As a method of image analysis, a method of automatically using commercially available software, for example, “ImageProPlus” manufactured by Nippon Rover Co., Ltd., or a method of extracting and analyzing manually traced ones can be adopted. .

  Information on the components obtained by the method for evaluating a porous assembly of the present invention can be obtained by using it for process management and product management when manufacturing a porous assembly and a composite material using the porous assembly. It will be possible to stably manufacture products of quality.

  Hereinafter, the present invention will be described more specifically with reference to production examples and examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

  In the following examples, the haze of the obtained composite was examined by measuring the haze value with C light using a haze meter manufactured by Suga Test Instruments in accordance with JIS standard K7136.

[Production Example 1: Preparation of dispersion]
Rice pine wood flour (Miyashita Wood Co., Ltd.) was degreased with a 2% by weight aqueous solution of sodium carbonate at 80 ° C. for 6 hours. Then, after washing with demineralized water, lignin was removed by immersing in an aqueous solution containing 0.66 wt% sodium chlorite and 0.14 wt% acetic acid at 80 ° C. for 5 hours. Next, after washing with demineralized water, filtration was performed, and the recovered purified cellulose was washed with demineralized water and then immersed in a 5 wt% aqueous potassium hydroxide solution for 16 hours to remove hemicellulose. Next, after washing with demineralized water, a 1% by weight aqueous dispersion was obtained.

[Production Example 2: Preparation of cellulose dispersion subjected to ultrahigh pressure homogenizer treatment]
Water was added to the cellulose dispersion obtained in Production Example 1 to adjust to 0.5% by weight. The separated liquid was subjected to a defibrating process at a jetting pressure of 245 MPa using an ultrahigh pressure homogenizer (Ultimizer) manufactured by Sugino Machine. The cellulose dispersion obtained by this fibrillation treatment is referred to as “ultra-high pressure homogenizer-treated cellulose dispersion”.

[Production Example 3: Preparation of cellulose dispersion subjected to grinder treatment]
Cellulose obtained in Production Example 1 from a raw material inlet through a stone mill of Masuyuki Sangyo Co., Ltd. using a supermass colloider MKCA6-2 and a GC6-80 stone mill with a gap of 80 μm and a rotational speed of 1500 rpm. The dispersion was adjusted to a cellulose concentration of 0.5%, and 1 liter was added for grinding treatment. The treated cellulose dispersion that passed through the grinder was again charged into the raw material inlet and passed through the grinder a total of 10 times. The cellulose dispersion obtained by this grinding treatment is hereinafter referred to as “grinder-treated cellulose dispersion”.

[Production Example 4: Preparation of cellulose dispersion subjected to ultrasonic treatment]
The cellulose dispersion was subjected to ultrasonic treatment using an ultrasonic homogenizer UH-600S (frequency 20 kHz, effective output density 22 W / cm ² ) manufactured by SMT.
Using a 36 mmφ straight tip (made of titanium alloy), tuning was performed with the output volume 8, and ultrasonic treatment was performed at 50% intermittent operation for 60 minutes at the optimum tuning position. The 50% intermittent operation is an operation in which an ultrasonic wave is oscillated for 0.5 seconds and then rested for 0.5 seconds.
The cellulose dispersion was cooled with cold water at 5 ° C. from the outside of the processing vessel, and the dispersion temperature was maintained at 15 ° C. ± 5 ° C., and the cellulose dispersion was processed while stirring with a magnetic stirrer.

[Example 1]
<Treatment of cellulose dispersion>
The cellulose dispersion obtained by subjecting the ultra-high pressure homogenizer-treated cellulose dispersion obtained in Production Example 2 to the same apparatus 5 times again was subjected to ultrasonic treatment according to the method of Production Example 4. . This cellulose dispersion was centrifuged using a HimacCR22G manufactured by Hitachi Koki Co., Ltd. using R20A2 as an angle rotor. Centrifugation was performed by installing eight 50 ml centrifuge tubes at an angle of 34 degrees from the rotation axis, and the amount of the cellulose dispersion put in one centrifuge tube was 30 ml, and centrifugation was performed at 18000 rpm for 30 minutes.

<Manufacture of cellulose nonwoven fabric>
The separation liquid obtained by centrifugation was diluted with water so that the cellulose concentration was 0.127% by weight, adjusted to 150 ml, and filtered under reduced pressure. Advantech KG-90 was used as a filter, and a PTFE (polytetrafluoroethylene) PTFE membrane filter made by Advantech was placed on the glass filter. The effective filtration area was 48 cm ² . The degree of vacuum during filtration was -0.09 MPa (absolute vacuum 10 kPa), and 30 ml of isopropyl alcohol was gently added from the top of the cellulose dispersion and filtered under reduced pressure.
By this filtration, a cellulose fiber deposit was obtained on the PTFE membrane filter. This cellulose deposit was press-dried at a pressure of 0.15 MPa for 5 minutes with a press machine heated to 120 ° C. to obtain a cellulose nonwoven fabric. The cellulose nonwoven fabric had a thickness of 66 μm.

<Sample preparation / microscopic observation>
The obtained cellulose nonwoven fabric was cut into 5 mm squares, impregnated with impregnation oil (IMMERSION OIL TYPE B / refractive index 1.5150 ± 0.0002 manufactured by CARGILLE LABORATORIES) on a slide glass, and covered with a cover glass. After standing in this state for 24 hours, it was observed with a polarizing microscope (Nikon optical microscope). In addition, by selecting a field of view representative of the sample shape, observing under crossed Nicols conditions, and synthesizing photographs taken at 10x and 40x magnifications while rotating the sample every 15 degrees, in-plane orientation A fiber shape image independent of corners was obtained. In this microscopic observation, it was possible to observe the entire structure from the surface of the sample to the internal structure having a depth of 66 μm, that is, the entire sample.
When the sample was observed by the above method, fibers having a fiber diameter of 0.4 μm or more were not observed at all. The photographs are shown in FIGS. 1 (a) and 1 (b). In addition, the part which looks white in FIG.1 (b) is not a fiber but the unevenness | corrugation of the sample surface.

<Manufacture of composite and haze measurement>
The obtained cellulose nonwoven fabric was mixed with 96 parts by weight of bis (methacryloyloxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane, ⁶ parts by weight of pentaerythritol tetrakisthio (β-propionate), 2,4,6- A mixed solution of 0.05 parts by weight of trimethylbenzoyldiphenylphosphine oxide (Lucirin TPO manufactured by BASF) and 0.05 parts by weight of benzophenone was impregnated and allowed to stand overnight under reduced pressure. This was sandwiched between two glass plates and irradiated with an electrodeless mercury lamp (“D bulb” manufactured by Fusion UV Systems) under an irradiation light amount of 400 mW / cm ² at a line speed of 7 m / min. The amount of light at this time was 0.12 J / cm ² . This operation was performed twice by inverting the glass surface. Next, irradiation was performed at a line speed of 2 m / min under an irradiation light amount of 1900 mW / cm ² . The amount of light at this time was 2.7 J / cm ² . This operation was performed 8 times by inverting the glass surface. The total amount of irradiation light was 21.8 J / cm ² . After the ultraviolet irradiation, the polymer cellulose composite was obtained by taking out from the glass plate and heating in a vacuum oven at 190 ° C. for 4 hours.
When the haze of this composite was measured by the above method, it was 0.97% and the transparency was high.

[Example 2]
The ultra-high pressure homogenizer-treated cellulose dispersion obtained in Production Example 2 was again passed through the same apparatus 10 times to obtain a cellulose dispersion. Using this cellulose dispersion, a cellulose nonwoven fabric was produced in the same manner as in Example 1. The cellulose nonwoven fabric had a thickness of 63 μm.

This cellulose nonwoven fabric was cut into 5 mm squares, impregnated with impregnation oil (IMMERSION OIL TYPE B / refractive index 1.5150 ± 0.0002 manufactured by CARGILLE LABORATORIES) on a slide glass, and covered with a cover glass. After standing in this state for 24 hours, it was observed with a polarizing microscope (Nikon optical microscope). In addition, by selecting a field of view representative of the sample shape, observing under crossed Nicols conditions, and synthesizing photographs taken at 10x and 40x magnification while rotating the sample every 15 degrees, in-plane orientation A fiber shape image independent of corners was obtained. In this microscopic observation, it was possible to observe the internal structure from the surface of the sample to a depth of 63 μm, that is, the structure of the entire sample.
When the sample was observed by the above measuring method, fibers having a fiber diameter of 0.4 μm or more were sparsely observed. The photographs are shown in FIGS. 2 (a) and 2 (b). In FIG. 2B, what looks like a white line is a fiber having a fiber diameter of 0.4 μm or more.

  Using this cellulose nonwoven fabric, a composite was produced in the same manner as in Example 1, and the haze of the obtained composite was measured. As a result, it was 2.66%, which was slightly inferior to that of Example 1. Met.

[Example 3]
A cellulose nonwoven fabric was produced in the same manner as in Example 1 using the grinder-treated cellulose dispersion obtained in Production Example 3 as it was. The cellulose nonwoven fabric had a thickness of 47 μm.

This cellulose nonwoven fabric was cut into 5 mm squares, impregnated with impregnation oil (IMMERSION OIL TYPE B / refractive index 1.5150 ± 0.0002 manufactured by CARGILLE LABORATORIES) on a slide glass, and covered with a cover glass. After standing in this state for 24 hours, it was observed with a polarizing microscope (Nikon optical microscope). In addition, by selecting a field of view representative of the sample shape, observing under crossed Nicols conditions, and synthesizing photographs taken at 10x and 40x magnification while rotating the sample every 15 degrees, in-plane orientation A fiber shape image independent of corners was obtained. In this microscopic observation, the internal structure from the surface of the sample to a depth of about 47 μm, that is, the structure of the entire sample could be observed.
When the sample was observed by the above measuring method, many fibers having a fiber diameter of 0.4 μm or more were observed. The photographs are shown in FIGS. 3 (a) and 3 (b). What appears to be a white line in FIG. 3B is a fiber having a fiber diameter of 0.4 μm or more.

  Using this cellulose nonwoven fabric, a composite was produced in the same manner as in Example 1, and when the haze of the obtained composite was measured, it was 5.52%, which was much inferior to that of Example 2. Met.

[Example 4]
The cellulose nonwoven fabric obtained in Example 2 was cut into 5 mm square, impregnated with impregnating oil (IMMERSION OIL TYPE B / refractive index 1.5150 ± 0.0002 manufactured by CARGILLE LABORATORIES) on a slide glass, and covered with a cover glass. It was. After standing in this state for 24 hours, a field of view representative of the sample shape was selected with a polarizing microscope (Nikon optical microscope), then observed under crossed Nicols conditions, and the sample was rotated 40 degrees while rotating every 15 degrees. Image analysis was performed using a fiber shape image independent of the in-plane orientation angle obtained by synthesizing photographs taken at a magnification of. In addition, with this microscopic observation, the internal structure having a depth of 63 μm from the surface of the sample, that is, the structure of the entire sample could be observed.
The distribution and aspect ratio were obtained by measuring the fiber diameter and fiber length of the observed fibers.
As a result of analysis, the average fiber length of fibers of 0.4 μm or more was 86.8 μm, the average fiber diameter was 8.1 μm, and the average aspect ratio was 12.5.

[Example 5]
The polymer cellulose composite obtained in Example 1 was cut into 5 mm squares, placed on a slide glass, and covered with a cover glass. This was observed with a polarizing microscope (Nikon optical microscope). In addition, by selecting a field of view representative of the sample shape, observing under crossed Nicols conditions, and synthesizing photographs taken at 10x and 40x magnification while rotating the sample every 15 degrees, in-plane orientation A fiber shape image independent of corners was obtained.
When the sample was observed by the above method, fibers having a fiber diameter of 0.4 μm or more were not observed at all. The photographs are shown in FIGS. 4 (a) and 4 (b).

As shown in the above examples, by using the evaluation method of the present invention, components of 0.4 μm or more (in the examples, cellulose fibers having a fiber diameter of 0.4 μm or more) could be observed. That is, by the method of the present invention, constituent elements of 0.4 μm or more present inside can be observed even though they are not visible from the surface of the porous assembly.
Further, as shown in Examples 1 to 3, the evaluation method of the present invention is obtained by impregnating the porous assembly with a resin content in the porous assembly and a content of 0.4 μm or more in the porous assembly. There is a correlation between the transparency of the composite, that is, the haze, and by using the measurement method of the present invention, it is possible to quantitatively evaluate the influencing factors of the transparent composite material of the porous aggregate. I understand that.
Furthermore, as shown in Example 4, by analyzing the image obtained by the evaluation method of the present invention, it is possible to measure the size and distribution of the constituent elements of 0.4 μm or more present per unit volume.

(A) The figure is an optical micrograph of the sample obtained by impregnating the cellulose nonwoven fabric obtained in Example 1 with oil. (B) The figure is observed under crossed Nicols conditions, and the sample is taken every 15 degrees. It is a composite photograph of a photograph taken while rotating it. (A) The figure is an optical micrograph of the sample obtained by impregnating the cellulose nonwoven fabric obtained in Example 2 with oil. (B) The figure is observed under crossed Nicols conditions and the sample is taken every 15 degrees. It is a composite photograph of a photograph taken while rotating it. (A) The figure is an optical micrograph of the sample obtained by impregnating the cellulose nonwoven fabric obtained in Example 3 with oil. (B) The figure is observed under crossed Nicols conditions, and the sample is taken every 15 degrees. It is a composite photograph of a photograph taken while rotating it. (A) The figure is an optical micrograph which uses the polymer cellulose composite obtained in Example 5 as a sample, and (b) the figure is observed under crossed Nicols conditions while rotating the sample every 15 degrees. It is a composite photo of the photograph taken.

Claims (8)

  After impregnating a porous assembly in which a plurality of constituent elements are aggregated with a liquid having a refractive index difference of 1 or less with respect to the refractive index of the constituent elements, by observing with a microscope, A method for evaluating a porous assembly, wherein the presence or absence is confirmed.   The evaluation of the porous aggregate according to claim 1, wherein the constituent elements are fibers and / or particles, and the presence or absence of fibers having a fiber diameter of 0.4 μm or more and / or particles having a particle diameter of 0.4 μm or more is confirmed. Method.   The method for evaluating a porous assembly according to claim 1, wherein the component is a crystalline component.   The method for evaluating a porous aggregate according to any one of claims 1 to 3, wherein the constituent element is cellulose.   The method for evaluating a porous aggregate according to any one of claims 1 to 4, wherein the porous aggregate is observed with a polarizing microscope.   The method for evaluating a porous assembly according to any one of claims 1 to 5, wherein a constituent element of 0.4 µm or more is confirmed and the size thereof is measured.   The method for evaluating a porous aggregate according to claim 6, wherein the constituent element is a fiber, and the fiber length and / or the fiber diameter is measured.   The method for evaluating a porous assembly according to claim 6, wherein the component is a particle, and the particle size thereof is measured.

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