JP2008106152A - Cellulose-containing resin composite - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin material that exhibits satisfactory heat resistance and excellent transparency and has a small linear expansion coefficient. <P>SOLUTION: The composite comprises a nonwoven fabric (a) comprising cellulose, a resin (b) other than cellulose and a flame-retarding agent (c), where the components (a), (b) and (c) account for at least 0.1 wt.% and at most 99 wt.%, at least 1 wt.% and at most 99.8 wt.%, and at least 0.01 wt.% and at most 50 wt.%, respectively. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a composite comprising a nonwoven fabric (a) containing cellulose, a resin (b) other than cellulose, and a flame retardant (c).

In general, glass plates are widely used as display element substrates (particularly active matrix type) for liquid crystal display elements and organic EL display elements, color filter substrates, solar cell substrates and the like.
However, in recent years, plastic materials have been studied as an alternative to glass plates because they are difficult to reduce in thickness, are easily broken, cannot be bent, have a large specific gravity, and are not suitable for weight reduction. For example, Patent Document 1 discloses a transparent resin substrate for a liquid crystal display element comprising a cured product obtained by curing an epoxy resin composition containing an epoxy resin, an acid anhydride curing agent and a curing catalyst, and Patent Document 2 includes A transparent resin substrate for a liquid crystal display element having two or more thermoplastic resin films and having an adhesive layer between the thermoplastic resin films is described. Patent Document 3 describes a liquid crystal display element using a transparent substrate obtained by curing and molding a composition containing a specific bis (meth) acrylate with active energy rays or the like.

A glass plate used for the display front plate is also being considered for a plastic plate. For example, Patent Documents 4, 5, and 6 show display front filters using polycarbonate, polyethylene terephthalate, or the like.
However, these conventional plastic materials for glass replacement have a larger coefficient of linear expansion than glass plates, and particularly when used for active matrix display element substrates, warping, cracking of deposited films, aluminum wiring Problems such as disconnection are likely to occur, and it is difficult to use for these purposes. Accordingly, there is a demand for a plastic material having a low linear expansion coefficient while satisfying transparency, heat resistance, etc. required for a display element substrate, particularly an active matrix display element substrate.

  In order to reduce the coefficient of linear expansion, it is common to combine an inorganic filler such as a glass fiber with a resin. However, when the resin and the inorganic filler are combined, a transparent composite material cannot usually be obtained. This is mainly because the light transmitted through the resin is scattered at the interface because the refractive index of the inorganic filler is different from the refractive index of the resin. In order to solve such a problem, various studies have been made to make the refractive index of the resin and the glass fiber transparent. For example, Patent Document 7 and Patent Document 8 show that a transparent composite material can be obtained by reducing the difference in refractive index between a cyclic olefin resin and glass fiber. Non-Patent Document 1 shows that a transparent composite can be obtained using an epoxy resin and glass fibers having a refractive index close to that. However, since the Abbe numbers of the glass fiber and the resin are different, it is difficult to match the refractive index for light of all wavelengths, and a phenomenon such as scattering of only light of a specific wavelength often occurs.

  On the other hand, as seen in the recent technological focus on global nanotechnology, one direction of material development is the control and focus on smaller structural units. Among these technical trends, the present inventors have developed a microfibrous cellulose (hereinafter referred to as microfiber) obtained from natural cellulose such as pulp having a fiber diameter of 1 μm or less disclosed in Patent Document 9 and Non-Patent Document 2. Fine and highly crystalline cellulose nanofibers (hereinafter referred to as fibrated cellulose or “MFC”) and acetic acid bacteria disclosed in Patent Document 10 having a thickness in the range of about several nm-200 nm , Bacterial cellulose, or “BC” for short). Such a film composed of cellulose nanofibers is known to have a very low linear expansion coefficient as disclosed in Patent Document 11 and Patent Document 12, and further, the gap is filled with a resin to form a hybrid. It is described that the material made to show the low linear expansion coefficient.

Recently, as disclosed in Non-Patent Document 3, a hybrid film obtained by hybridizing an epoxy resin or an acrylic resin to a BC film obtained by pressing and drying a BC gel obtained by stationary culture is Since it has a low linear expansion coefficient and high transparency, it has been reported to be effective as an optical film.
However, according to Non-Patent Document 3 described above, the BC membrane obtained by static culture is a membrane having a very dense structure, so that it is impregnated with a resin monomer when preparing a composite containing 65% cellulose fibers. This requires extremely long time and immersion under reduced pressure (after immersion for 12 hours under reduced pressure and then for 4 days at 20 ° C. under normal pressure), which is extremely disadvantageous from the viewpoint of industrial production. In this technique, cellulose, which is the main component of the low linear expansion coefficient, is originally a hygroscopic material, and has a characteristic that physical properties are likely to change with moisture absorption. Accordingly, there has been a demand for reducing the BC or cellulose fraction in the hybrid film as much as possible. Patent Document 12 discloses the fact that the above-mentioned hybrid material can be obtained when bacterial cellulose having a specific shape is used. In order to produce the material industrially, cellulose raw material is disclosed. While the versatility of the conditions required for the membrane is necessary, the structural constraints required for the cellulose membrane to achieve a low linear expansion coefficient need to be clarified.

Furthermore, it is desirable that the membrane made of BC or fine cellulose, which can be a raw material of the hybrid film, be supplied by a continuous production process capable of industrial production rather than a batch static culture method. In that case, cellulose can be easily dispersed in a dispersion medium such as water and then formed by a papermaking method or a cast film forming method. However, various devices are required for the dispersion method and the film forming conditions. Only when a hybrid film is formed using a cellulose film having remarkably improved film quality uniformity, it can be applied as a precision material such as an optical film.
That is, in order to be able to provide the technology industrially in providing a transparent film having a low linear expansion coefficient by hybridizing a film made of cellulose nanofibers and a polymer resin, there are some problems described above. There was a need to solve.

The cited references are listed below. Non-patent documents 4 and later are cited in the section of [Best Mode for Carrying Out the Invention].
JP-A-6-337408 JP-A-7-120740 International Publication Number WO2002 / 074532 JP 2003-295778 A JP 2003-5659 A JP-A-10-90667 JP-A-6-256604 JP-A-6-305077 JP-A 56-1000080 Japanese Examined Patent Publication No. 6-43443 International Publication Number WO2003 / 040189 JP 2004-270064 A Abstracts of Symposium on Composite Materials, 22, 86 (1997) J.Appl.Polym.Sci., Appl.Polym.Symp., 37, 797-813 (1983) Abstracts of 11th Annual Meeting of Cellulose Society, p1-p2 Cellulose-Structural and Functional Aspects, Editted by JF Kennedy, GOPhilips and PAWilliams, John Wiley & Sons, p87-92, 1989 “PolymerHandbook 3rd Edition”, Ed. By J. Brandrup and EHImmergut, John Wiley & Sons, New York, 1989 M. Kerker, “The Scattering of Light”, USA, Academic Press, New York, NY, 1969, Cap. 5. Environmentally friendly-non-halogen, low harmful, low smoke generation-latest flame retardants and flame retardant technology, 1999, p. 56-78 (published by Technical Information Association) Chemical Review, No. 39, 1998 (published by Academic Publishing Center) A. Asano, T. Kinoshita, SID Digest2002, 1196 (2002)

  The objective of this invention is providing the resin material which is excellent in transparency, and has a small linear expansion coefficient, satisfying heat resistance.

That is, the present invention
[1] It comprises a nonwoven fabric (a) containing cellulose, a resin (b) other than cellulose, and a flame retardant (c), and the component (a) is 0.1 wt% or more and 99 wt% or less ( b) Component is 1% by weight or more and 99.8% by weight or less, and (c) Component is 0.01% by weight or more and 50% by weight or less.
[2] The composite according to [1], wherein the pores of the nonwoven fabric (a) containing cellulose are filled with a resin (b) other than cellulose.
[3] The composite according to any one of [1] or [2], wherein a nonwoven fabric having a porosity of 35% or more and 95% or less is used as the nonwoven fabric (a) containing cellulose.
[4] The composite according to [3], wherein a nonwoven fabric having a porosity of 50% or more and 95% or less is used as the nonwoven fabric (a) containing cellulose.
[5] The composite according to [4], wherein a nonwoven fabric having a porosity of 70% or more and 95% or less is used as the nonwoven fabric (a) containing cellulose.

[6] As the nonwoven fabric (a) containing cellulose, an average transmittance Tr defined by the following formula (1) obtained by vertically scanning light of 850 nm with respect to the nonwoven fabric in a state immersed in toluene, A composite according to any one of [1] to [5], wherein a nonwoven fabric containing cellulose having an av of 0.70 or more is used.
However, Tr and av are filled with toluene in a state in which the nonwoven fabric is adhered to the inner surface of the test tube, irradiates the test tube with light of 850 nm from a direction perpendicular to the nonwoven fabric, and linearly extends along the surface of the nonwoven fabric. Obtained by performing the same measurement in a state where only toluene is injected except for the nonwoven fabric, and the average value Tr, 1 of the transmittance obtained when scanning for a total length of 30000 μm (data points: 750) every 40 μm. It is defined by the following equation depending on the ratio of the average values Tr and 2 of transmittance.
Tr, av = Tr, 1 / Tr, 2 (1)

[7] The nonwoven fabric (a) containing cellulose uses a nonwoven fabric having a film quality uniformity parameter H defined by the following formula (2) of 0.018 or less. Complex.
However, H is filled with toluene in a state where the nonwoven fabric is adhered to the inner surface of the test tube, irradiated with light of 850 nm from the direction perpendicular to the nonwoven fabric, and 40 μm in a linear direction along the surface of the nonwoven fabric. Permeability obtained by performing the same measurement in the state in which only toluene is injected except for the standard deviation Tr, sd1 and the non-woven fabric of the transmittance obtained when scanning for a total length of 30000 μm (data score: 750) for each The following equation is defined by Tr and av obtained by Equation (1) in the same measurement as Tr and sd defined by the difference between the standard deviations Tr and sd2.
H = Tr, sd / Tr, av (2)
Here, Tr, sd = Tr, sd1-Tr, sd2.

[8] As a nonwoven fabric (a) containing cellulose, cellulose fibers having a maximum fiber thickness of 2 to 1500 nm obtained by forming a film from a dispersion containing cellulose fibers by a papermaking method or a coating method are entangled. The composite according to any one of [1] to [7], wherein a nonwoven fabric is used.
[9] A nonwoven fabric obtained by a papermaking method as a nonwoven fabric (a) containing cellulose, and as a dispersion for papermaking, the dispersion average diameter of cellulose fibers is 1 μm or more and 300 μm or less, and the cellulose fiber concentration is 0.01 A dispersion having a weight percentage of not less than 1.0% and not more than 1.0% is used, and as a filter cloth, it has the ability to filter out 95% or more of cellulose fibers in a papermaking dispersion by filtration at 25 ° C. under atmospheric pressure. Using a filter cloth having a water permeation amount of 0.005 cc / cm ² · s or more at 25 ° C. under atmospheric pressure, installing the filter cloth on the wire of the paper making apparatus and filtering the papermaking dispersion liquid on the filter cloth. The cellulose fiber is deposited on the filter cloth to produce a wet nonwoven fabric with a solid content of 4% by weight or more of the fine cellulose fiber, and the nonwoven fabric is peeled off from the filter cloth before or after the drying process. A composite according to any one of [1] to [8] the cellulose fibers maximum fiber thickness is 1500nm or less which is characterized by using a nonwoven fabric formed by entangling.

[10] The non-woven fabric produced by a production method including a step of replacing a dispersion medium in a papermaking dispersion with an organic solvent before the drying step is used as the non-woven fabric (a) containing cellulose. [9] The complex according to [9].
[11] The composite according to any one of [1] to [10], wherein an average linear expansion coefficient at 50 to 150 ° C is 0.1 ppm / ° C to 25 ppm / ° C.
[12] The composite according to any one of [1] to [11], wherein an average linear expansion coefficient at 50 to 250 ° C is 0.1 ppm / ° C to 30 ppm / ° C.
[13] The composite according to any one of [1] to [12], wherein a relationship of storage elastic modulus in dynamic viscoelasticity measurement satisfies the following formula.
1≤E'30 / E'150≤100
E'30: Storage elastic modulus of the composite at 30 ° C E'150: Storage elastic modulus of the composite at 150 ° C

[14] The composite according to any one of [1] to [13] above, wherein the storage elastic modulus E′150 at 150 ° C. of the composite in dynamic viscoelasticity measurement is 100 to 30000 MPa. .
[15] The composite according to any one of [1] to [14], wherein a relationship of storage elastic modulus in dynamic viscoelasticity measurement satisfies the following formula.
1 ≦ E'30 / E'250 ≦ 100
E′30: Storage elastic modulus of the composite at 30 ° C. E′250: Storage elastic modulus of the composite at 250 ° C. [16] Storage elastic modulus E′250 at 250 ° C. of the composite in dynamic viscoelasticity measurement is 100 to 100 The composite according to any one of [1] to [15], which is 30000 MPa.

[17] The composite according to any one of [1] to [16], wherein the total light transmittance is 60% or more.
[18] The composite according to any one of [1] to [17], wherein the haze value is 80% or less.
[19] The composite according to any one of [1] to [18], wherein an in-plane retardation (Re) at a wavelength of 550 nm is 50 nm or less at a thickness of 100 μm.
[20] The composite according to any one of [1] to [19], wherein the absolute value of the photoelastic coefficient is 80 × 10 ¹² / Pa or less.
[21] The composite according to any one of [1] to [20], wherein the nonwoven fabric (a) containing cellulose is a nonwoven fabric having a thickness in the range of 5 μm to 500 μm.
[22] The composite according to any one of [1] to [21], wherein a nonwoven fabric produced using bacterial cellulose is used as the nonwoven fabric (a) containing cellulose.

[23] A nonwoven fabric produced using cellulose obtained by refining wood-based cellulose, non-wood-based natural cellulose, or regenerated cellulose as the nonwoven fabric (a) containing cellulose. The complex according to any one of [1] to [21].
[24] The composite according to any one of [1] to [23], wherein a nonwoven fabric produced using cellulose whose surface is chemically modified is used as the nonwoven fabric (a) containing cellulose. body.
[25] A nonwoven fabric containing at least one selected from boric acid and a boric acid compound as the flame retardant (c), wherein the flame retardant is immobilized on the surface of cellulose, and cellulose by the flame retardant The composite according to any one of [1] to [23], wherein at least one selected from nonwoven fabrics whose surfaces are chemically modified is used.

[26] The composite according to any one of [1] to [25], wherein the cellulose-containing nonwoven fabric (a) is a continuous nonwoven fabric prepared by a continuous process.
[27] The nonwoven fabric according to any one of [1] to [26], wherein the nonwoven fabric (a) containing cellulose, which is a continuous nonwoven fabric created in a continuous process, is further continuously composited. Complex.
[28] The composite according to any one of [1] to [27], wherein the refractive index of the resin (b) other than cellulose is greater than 1.48 and less than 1.62.
[29] The composite according to any one of [1] to [28], wherein the resin (b) other than cellulose is made of a styrene resin.

[30] The resin (b) other than cellulose is a styrene resin obtained by copolymerizing an acrylic resin monomer and a styrene resin monomer, as described in [29] above Complex.
[31] The composite according to any one of [1] to [28], wherein the resin (b) other than cellulose is a resin obtained by blending an acrylic resin and a styrene resin. .
[32] The composite according to any one of [1] to [28], wherein the resin (b) other than cellulose is an aromatic polycarbonate resin.
[33] The composite according to any one of [1] to [28], wherein the resin (b) other than cellulose is composed of a cyclic olefin resin.
[34] The composite according to any one of [1] to [28], wherein the resin (b) other than cellulose is composed of an epoxy resin.
[35] The composite according to any one of [1] to [34], wherein the flame retardant (c) is a hydrate flame retardant.
[36] The composite according to any one of [1] to [34], wherein the flame retardant (c) is a low-melting glass-based flame retardant.

[37] For the nonwoven fabric (a) containing cellulose,
(1) A method in which a monomer is impregnated and polymerized.
(2) A method in which a thermosetting resin precursor or a photocurable resin precursor is impregnated and cured.
(3) A method of drying after impregnating a solution of a resin other than cellulose.
(4) A method of impregnating a thermoplastic resin melt and cooling after defoaming.
The method for producing a composite according to any one of [1] to [36], wherein the resin (b) other than cellulose is filled and composited by any one of the methods.
[38] A plastic substrate for display comprising the composite according to any one of [1] to [36].
[39] A plastic substrate for a display front plate, comprising the composite according to any one of [1] to [36], and having a thickness of 5 to 500 μm.
[40] A display using the plastic substrate according to [38] or [39].

[41] The display according to [40], wherein the display is a liquid crystal display.
[42] The display according to [40], wherein the display is an organic electroluminescence (organic EL) display.
[43] The display according to [40], wherein the display is a plasma display.
[44] The display according to [40], wherein the display is a field emission display.
[45] The display according to [40], wherein the display is a surface electric field display.
It is.

  The composite of the present invention is industrially useful because it is excellent in transparency and has a low coefficient of linear expansion while satisfying heat resistance. In particular, these characteristics are useful for various displays.

Next, the present invention will be described in more detail.
In the present invention, the cellulose-containing non-woven fabric (a) is a resin impregnated property obtained by using a fixed length drying with a drum dryer or an organic solvent substitution / drying method on a gel film obtained by a stationary culture method using bacteria. Prepare a non-woven fabric (paper) or a dispersion containing cellulose in which fine cellulose fibers such as BC and MFC are highly dispersed, and form this by either papermaking or coating. Inorganic fibers such as thermoplastic resin fibers, glass fibers, carbon fibers, metal fibers, natural fibers, organic fibers, and silica are mixed into the dispersion together with cellulose as fibers other than cellulose. The manufactured nonwoven fabric is also included.

  The thickness of the nonwoven fabric is not particularly limited, but is preferably 5 μm or more and 500 μm or less, more preferably 10 μm or more and 300 μm or less, and particularly preferably 20 μm or more and 200 μm or less. From the viewpoint of the strength of the nonwoven fabric, the thickness is preferably 5 μm or more, and a nonwoven fabric having a thickness of 500 μm or less does not require much time to impregnate the resin, and is therefore suitable for the industrial production process of compounding. It is preferable. In particular, from the viewpoint of industrial production, a method of forming a film by a paper making method or a coating method from a dispersion of fine cellulose fibers is more preferable than a method of forming a film by stationary culture, because of its large area and excellent quality stability. In the case of the stationary culture method using bacteria, it is particularly preferable to use a high-porosity nonwoven fabric by appropriately selecting the drying method described later in order to enhance the resin impregnation property.

In addition, in this invention, the film thickness of the nonwoven fabric (a) containing a cellulose cuts this nonwoven fabric into a 10 square cm square, and uses a point contact type | mold film thickness meter (Mittoyo Co., Ltd. code; 547-401). Used, defined by the average value obtained by measuring 5 points for various positions of the nonwoven fabric.
Moreover, it is preferable that the fiber diameter of a cellulose fiber is comprised from the thin thing. More specifically, it is preferable not to contain fibers having a fiber diameter of a certain value or more, that is, the maximum fiber diameter of the fibers constituting the nonwoven fabric is preferably 1500 nm or less, more preferably 1000 nm or less, and particularly preferably 500 nm or less. When it is, the composite_body | complex of this invention can be produced suitably. In particular, when the maximum fiber diameter is 1500 nm or less, the composite of the present invention has extremely high transparency, and can be suitably used as a film or sheet-like molded body that can be developed for optical applications. Further, it is preferable because the mechanical strength is high and the coefficient of linear expansion is low. The present invention is also effective for fine fiber having a lower limit of the maximum fiber diameter of 2 nm.

  In the present invention, it is confirmed by SEM images that the maximum fiber thickness of fine cellulose fibers and other fibers is 1500 nm or less as follows. That is, the surface of the nonwoven fabric containing cellulose that is a material for producing the composite of the present invention is randomly observed at three locations with a scanning electron microscope (SEM) at a magnification equivalent to 10,000 times. When no single fiber having a fiber thickness exceeding 1500 nm can be confirmed in all the obtained SEM images, it is defined that the maximum fiber thickness is 1500 nm or less. The same definition applies to 1000 nm or less and 500 nm or less. However, in the image, when it can be clearly confirmed that several fine fibers are bundled and have a fiber thickness exceeding 1500 nm, it is not regarded as a fiber having a fiber thickness exceeding 1500 nm.

  An example of such a measurement is shown in FIG. FIG. 1 shows a wet paper obtained by a papermaking method from an aqueous dispersion of fine cellulose fibers obtained by high-pressure homogenizer treatment (operating pressure; 100 MPa, number of passes through a homovalve; 20 passes) of Ecuadorian abaca pulp. In this case, a non-woven fabric (manufactured by performing substitution treatment on an ethyl cellosolve / water = 80/20 (g / g) mixed solution containing 3% by weight of boric acid and then drying at 100 ° C. with a drum dryer It is a part of the image regarding CC-1) of Example 1. In both cases, there is obviously no fiber having a fiber thickness exceeding 1500 nm, and therefore this corresponds to a nonwoven fabric in which cellulose fibers having a maximum fiber thickness of 1500 nm or less are entangled.

Furthermore, in the present invention, the cellulose that is the raw material of the nonwoven fabric (a) containing cellulose is bacterial cellulose produced by bacteria, cellulose obtained from purified pulp obtained from wood (coniferous and hardwood) (hereinafter “wood-based cellulose”). Natural cellulose, excluding wood-based cellulose, is also referred to as “non-wood-based natural cellulose” hereinafter), cotton linter, cotton lint, bamboo, hemp (abaca, etc.), bagasse, kenaf, and straw. Examples include natural celluloses such as cellulose obtained from non-wood plants, cellulose obtained from seaweeds such as valonia and clover, and cellulose obtained from sea squirts. In addition, both cellulose obtained by artificially refining the natural cellulose or cellulose obtained by refining regenerated cellulose fibers represented by rayon fibers and cupra fibers can be used.
Among them, so-called bacterial cellulose (BC) produced by microorganisms such as acetic acid bacteria belonging to the Acetobacter group and CJF002 bacteria belonging to the Enterobacter group is a never-dry aqueous dispersion composed of fine fibers having a fiber diameter of 100 nm or less (in some cases Can be prepared as a gel), it is possible to prepare a dispersion for use in papermaking or coating under relatively mild dispersion conditions, which is technically advantageous.

  On the other hand, versatile cellulose raw materials such as wood-based cellulose and non-wood-based natural cellulose other than BC are originally composed of fine fibers called microfibrils of 100 nm or less. However, since it exists in a dry state in nature, a multi-bundle progresses in the drying process and exists as a thicker fiber (the same applies to regenerated cellulose fiber). In order to use such a versatile cellulose raw material in the present invention, a refining device having the ability to break apart a multi-bundle fiber such as a high-pressure homogenizer, a grinder, or an ultra-high pressure homogenizer, such as MFC, is used. It is preferable to repeat the refining treatment to create a state in which a large number of fibers of 100 nm or less are contained and fibers having a fiber diameter exceeding 1500 nm do not exist.

  For example, pulp made by refining abaca, hemp fiber, or refined bamboo refined pulp is a highly refined fiber with a maximum fiber diameter of 500 nm or less, so a highly transparent resin composite Suitable for getting the body. The use of versatile refined pulp as a starting material is particularly preferable because it is economically superior to the case of using BC. In addition, when preparing fine cellulose fibers by refinement from general-purpose cellulose raw materials, for example, pretreatment of the raw materials at high temperature and high pressure before reaching the miniaturization treatment step with a high-pressure homogenizer, grinder, ultra-high pressure homogenizer, etc. Highly fine fibers can be obtained by applying (autoclave treatment), blasting treatment, or beating treatment (beater treatment, disc refiner treatment, etc.) used for the purpose of promoting fibrillation in the paper industry. Not only can this be done, but it also leads to a reduction in the load of the miniaturization process, which has an industrially high energy load, which is advantageous in terms of cost.

  Furthermore, in this invention, you may use the nonwoven fabric manufactured using the cellulose by which the surface was chemically modified as a nonwoven fabric (a) containing a cellulose. Chemical modification of the surface includes oxidation of the hydroxyl group (aldehyde or carboxylation at the C6 position), esterification of the hydroxyl group (acetate esterification, nitrate esterification, sulfate esterification, borate esterification, phosphate esterification, fatty acid ester) Esterification, etc.), cross-linking reaction between surface OH (cross-linking with formaldehyde, cross-linking with various cross-linking agents such as bifunctional urethane), oxidation reaction with cleavage between glucopyranoses, etc. Not. However, destruction of the cellulose structure inside the fiber by these reactions must be avoided. From this viewpoint, it is preferable that esterification is performed with acetic acid or boric acid which are weak acids. The destruction of the cellulose structure is a state in which any one of the peak patterns (Non-patent Document 4) attributed to the C1-C6 position attributed to cellulose in the solid-state NMR method (13C-CP / MAS method) described later completely disappears. Means.

The use of such chemically modified cellulose as a raw material for the nonwoven fabric may be effective for improving the strength of the nonwoven fabric (a) containing cellulose. It can also be an improvement method when the inherent properties are weak points in the use of the composite. Among these, a borate ester of cellulose can be preferably used for imparting flame retardancy and heat resistance, and particularly borate esterification in cellulose used in the composite of the present invention dramatically improves flame retardancy and heat resistance. Improve.
The respective weight fractions of the nonwoven fabric (a) component containing cellulose and the resin (b) component other than cellulose in the composite of the present invention are 0.1 wt% or more and 99 wt% or less / 1 wt% or more 99.8. % By weight or less, preferably 1% by weight or more and 90% by weight or less / 10% by weight or more and 99% by weight or less, more preferably 5% by weight or more and 60% by weight or less / 40% by weight or more and 95% by weight or less. It is necessary that the weight content of the component (a) is 0.1% by weight or more because the low linear expansion coefficient in the present invention is manifested, and that the content is 99% by weight or less. It is necessary to make a highly transparent composite. Furthermore, when the weight content of the component (b) is 1% by weight or more, it is suitable for increasing the transparency of the composite, and the content is 99.8% by weight or less. Is required to express

  In the composite of the present invention, the pores of the nonwoven fabric (a) containing cellulose are preferably filled with a resin (b) other than cellulose. For this reason, the porosity of the nonwoven fabric (a) containing cellulose is obtained by impregnating the non-cellulose resin (b) and the flame retardant (c) into the nonwoven fabric (a) containing cellulose. From the viewpoint of the transparency and moldability of the composite, it is preferably 35% or more. Moreover, it is preferable that it is 95% or less from a viewpoint of the linear expansion coefficient of a composite_body | complex, intensity | strength, and heat resistance. More preferably, the porosity is 50% or more and 95% or less, and particularly preferably, the porosity is 70% or more and 95% or less. When the porosity is 50% or more, since the impregnation rate of the component (b) into the component (a) is high, the winding speed of the roll can be increased and the productivity is improved. Also, bubbles due to insufficient impregnation do not remain in the composite, and a composite having excellent transparency and low water absorption can be obtained continuously. Further, when the porosity is 95% or less, the strength is high, and it is difficult to break in the production process. Therefore, a composite having high strength and heat resistance and low linear expansion can be obtained continuously. In other words, when a nonwoven fabric containing (a) cellulose having a porosity of 50% or more and 95% or less is used, a composite excellent in balance of transparency, water absorption, heat resistance, strength, and linear expansion coefficient is industrially produced. From the point of view, it can be obtained realistically (eg continuous production).

In addition, the porosity of the nonwoven fabric containing a cellulose calculates porosity Pr (%) using the following formula | equation from the film thickness d (micrometer) of this nonwoven fabric 10cm square, and its weight W (g). It is a thing.
Pr = (d−W × 67.14) × 100 / d
In addition, the composite of the present invention can be obtained by using a resin having a high viscosity as the resin (b) other than cellulose, by reducing the pressing pressure when forming the composite, or by laminating the composite film and other resin films. In the non-woven fabric (a) containing cellulose, the resin can have a single phase other than the pores, and depending on the required physical properties, each weight fraction of the component (a) / component (b) in the composite Can be adjusted.

  The heat resistance of the composite can be judged from the relationship of the storage elastic modulus in the dynamic viscoelasticity measurement. When the storage elastic modulus of the composite at 30 ° C is E'30, the storage elastic modulus of the composite at 150 ° C is E'150, and the storage elastic modulus of the composite at 250 ° C is E'250, E'150 and E It is considered that the higher the value of '250, the higher the heat resistance, the higher the heat treatment in the manufacturing process, and the higher the heat resistance in the use environment. In the present invention, the storage elastic modulus value E′150 of the composite at 150 ° C. is preferably 100 to 30000 MPa. Further, the value of the storage elastic modulus ratio E′30 / E′150 of the composite at 30 ° C. and 150 ° C. is preferably 1 to 100. In particular, when a crosslinkable resin such as a thermosetting resin or a photocurable resin that is expected to have heat resistance at 250 ° C. is combined as a resin (b) other than cellulose, the storage elastic modulus value E ′ of the composite is obtained. 250 is 100 to 30000 MPa, preferably the value of the storage elastic modulus ratio E′30 / E′250 of the composite at 30 ° C. and 250 ° C. is 1 to 100, more preferably the ratio E′30 / E′250. When the value is 1 to 10, since the decrease in elastic modulus in the glass transition temperature region and the rubber-like flat region of the resin of component (b) is extremely small, physical properties such as strength at high temperatures are unlikely to decrease. After the high-temperature treatment process in the manufacturing process, the change in elastic modulus in the process of returning to room temperature and the process of temperature change in the usage environment is small, which is preferable because warpage, disconnection of the aluminum wiring, peeling of the surface coating film, etc. do not occur.

Another index of heat resistance is discoloration after high temperature treatment, for example, yellowness defined by JISK-7105. In order to achieve the object of the present invention, the yellowness of the composite after high temperature treatment (dry heat treatment in the atmosphere at 250 ° C. for 30 minutes) is preferably 50 or less, more preferably 30 or less, and 20 More preferably, it is as follows.
Next, the non-woven fabric (a) containing cellulose used in the present invention is defined by the following formula (1) obtained by vertically scanning 850 nm light with respect to the non-woven fabric in a state of being immersed in toluene. The average transmittances Tr and av are preferably 0.70 or more, more preferably 0.75, and particularly preferably 0.80 or more.

  Within this range, it is possible to provide a composite having high transparency and excellent uniformity. That is, Tr and av are preferably 0.70 or more from the viewpoint of transparency, uniformity, and linear expansion coefficient of the composite. This is due to the following reason. Nonwoven fabric containing cellulose having a slight refractive index difference with respect to toluene having a refractive index of 1.496 at 20 ° C. (According to Non-Patent Document 5, the refractive index is 1. depending on the type of cellulose and the orientation of the sample. When the fibers constituting the nonwoven fabric include a large number of fibers having a fiber diameter not sufficiently smaller than about 400 nm, the scattering at the interface is caused by the nonwoven membrane film. Since it acts as an inhibitor of light transmission, the average transmittance value under the above conditions is a physical property value reflecting the fineness of the constituent fibers of the nonwoven fabric or the fineness of the network structure of the nonwoven fabric. In the present invention, since the space in the nonwoven fabric containing cellulose is filled with a resin to form a composite, the average transmittances Tr and av obtained under the above conditions naturally correlate with the transparency of the obtained composite. .

  Here, in the present invention, Turbiscan TMMA-2000 (Eihiro Seiki Co., Ltd.) is used in the measurement of Tr and av. This device was originally developed to evaluate the aging stability of solutions and dispersions, but the nonwoven fabrics that are the subject of the present invention were immersed in toluene and the measurements described below were performed. The inventors are extremely sensitive to information on the diameter of the fibers constituting the nonwoven fabric and information on the fineness of the network structure in the nonwoven fabric, and are extremely effective for the purpose of clarifying the differentiation between samples. Was found by.

The measurement of Tr and av of the nonwoven fabric is performed as follows using the above apparatus. First, a target nonwoven fabric sample is cut into a 10 mm × 50 mm rectangle, immersed in a sample tube filled with toluene, and subjected to vacuum defoaming for the purpose of removing bubbles inside the nonwoven fabric. Next, the long axis of the nonwoven fabric sample impregnated with toluene is placed at a position where toluene is poured into a glass test tube attached to the apparatus so as to have a height of 5 cm and is in contact with the bottom cover of the test tube. Install in close contact with the inner wall of the test tube so that it is along the length of the test tube. At this time, the laser beam is installed perpendicularly to the vicinity of the center of the nonwoven fabric sample and at a position where the laser beam strikes the nonwoven fabric from the near wall surface. This state is shown in FIG. Next, according to the usual usage of the apparatus, a laser beam of 850 nm is scanned in the length direction of the test tube. The device detects the transmittance Tr in the length direction of the test tube in a range of 60 mm in total every 40 μm by a conventional method, but confirms this profile and cuts the center 30 mm of the portion considered to be hit by the nonwoven fabric. (As a target), the average value of the transmittance Tr of a total of 750 points, Tr, 1 is calculated (FIG. 3). Next, the same measurement is performed in a state where only 5 cm of toluene is injected into the same test tube as the above measurement (no nonwoven fabric is installed), and the average value of the transmittance Tr of 750 points, Tr, 2 is also calculated. . Using the Tr, 1 and Tr, 2 obtained in this manner, the transmittance, Tr, av, of the nonwoven fabric under toluene impregnation is obtained by Equation (1).
Tr, av = Tr, 1 / Tr, 2 (1)

Next, in the above measurement, when the standard deviation of the Tr measurement in the presence of the nonwoven fabric is Tr, sd1, and the standard deviation of the Tr measurement with only toluene is Tr, sd2, the transmittance of the nonwoven fabric membrane in the toluene-impregnated state. The standard deviation Tr, sd of the distribution
Tr, sd = Tr, sd1-Tr, sd2
Using this, the film quality uniformity parameter H is defined by equation (2) as a measure of film quality uniformity in the toluene impregnation state.
H = Tr, sd / Tr, av (2)
At this time, the non-woven fabric containing cellulose used in the present invention is as described above, but the average transmittance Tr, av is 0.70 or more, and at the same time, the H value is 0.018 or less. An excellent composite of the present invention can be provided. Preferably, when the value of H is 0.012 or less, more preferably 0.008 or less, the composite of the present invention having extremely excellent uniformity can be provided. It is preferable to use a non-woven fabric having a value of H of 0.018 or less from the viewpoint of variation in the density of cellulose existing in the portion when the composite is formed. If there is a variation in the density of cellulose, low density places become structural defects, and as a result, the strength of the composite as a whole is reduced, which is not appropriate.

In order to provide a non-woven fabric that is excellent in transparency under toluene impregnation satisfying such conditions of Tr, av and H, and excellent in film quality uniformity, it is necessary to pay attention to the following points. First, it is preferable to use a fiber having the smallest possible fiber diameter. Specifically, the maximum fiber diameter is preferably 1500 nm or less, more preferably 1000 nm or less, and most of the fibers formed at the same time are preferably composed of fibers of 500 nm or less, more preferably 400 nm or less. More specifically, it is preferable that 50% or more of the fibers in the non-woven fabric confirmed by SEM are fibers of 500 nm or less.
Next, when forming the film, it is extremely important to prepare a dispersion with as high uniformity as possible regardless of whether it is a papermaking method or a coating method. Although this condition (dispersing means and the like) will be described later, an appropriate dispersing means is selected according to the selected film forming method. Furthermore, Tr, av, and H are described above by following the contents based on the method for producing a nonwoven fabric disclosed in the present invention (for example, in the case of the papermaking method, use a filter cloth under appropriate conditions). A membrane controlled to a range can be suitably provided.

  In the present invention, it is preferable that a dispersion in which cellulose fibers are dispersed in water, an organic solvent or a mixed solvent thereof is first prepared, and then the dispersion is formed into a film by a papermaking method or a film is formed by a coating method. The nonwoven fabric (a) containing cellulose that can be used in the invention can be produced. However, in the present invention, since fine cellulose fibers are used as described above, it is extremely important to prepare a dispersion controlled to an appropriate dispersion state. In addition, the flame retardant (c, in particular, significantly improves the heat resistance of the cellulose fibers constituting the nonwoven fabric (a), and as a result, the linear expansion coefficient as a composite can be significantly reduced as compared with an unblended composite. It is preferable to add and blend when forming the nonwoven fabric (a) made of cellulose.

In the coating method, after coating, the dispersion medium is dried to form a film. Therefore, it is desirable to disperse the cellulose fibers as high as possible in the dispersion used. On the other hand, in the papermaking method in which the dispersion liquid is usually cast on a metal wire and then the dispersion medium is filtered, the dispersion liquid is not excessively dispersed and the fibers are appropriately associated without aggregation. Need to produce. These states are controlled by selection of a disperser, dispersion conditions, addition of a mixed medium such as an organic solvent into the dispersion, a dispersion aid, and the like.
Although fine cellulose fibers are used in the present invention, a blender type disperser or a high-pressure homogenizer is effective as a disperser effective for increasing the dispersion state. is there. Further, since such a dispersion works so that the fine cellulose fibers themselves stabilize the dispersion of the cellulose fibers, a stable dispersion can be obtained at a higher concentration. In particular, in the coating method in which the drying process is performed as it is from the state of the applied dispersion, it is desirable to set the concentration of cellulose fibers in the dispersion higher, preferably 0.3% by weight to 3.0% by weight More preferably, it is 0.4 wt% or more and 2.5 wt% or less, and particularly preferably 0.5 wt% or more and 2.0 wt% or less. Furthermore, the flame retardant (c) is desirably dissolved or dispersed in a dispersion when the nonwoven fabric (a) is formed by a coating method.

  Since the viscosity of the dispersion can vary greatly depending on the presence or absence of the dispersion medium and additives, the concentration of the cellulose fibers is appropriately set so that the viscosity is appropriate for the coating step. If it is 0.3% by weight or more, it is advantageous from the viewpoint of industrial production because a large amount of energy is not required to remove the dispersion medium such as water, and any blending is possible at a fiber concentration lower than 3.0% by weight. The composition is preferable in terms of operation without the viscosity being too high. In addition to the flame retardant, the dispersion liquid includes inorganic substances such as silica and fibers other than cellulose (thermoplastic resin fibers, glass fibers, carbon fibers, metal fibers, natural fibers, organic fibers). ) And the like can be mixed to produce a nonwoven fabric (a) containing cellulose. Thus, when using fibers other than cellulose, the maximum fiber thickness is not particularly limited, but is preferably 1500 nm or less, more preferably 1000 nm or less, and particularly preferably 500 nm or less. It is possible to obtain a highly transparent material by using.

Next, the manufacturing method which forms into a film by the papermaking method the nonwoven fabric containing the cellulose used in manufacture of the composite_body | complex of this invention is described.
A dispersion for papermaking of cellulose fibers having a maximum fiber thickness of 1500 nm or less, a dispersion average diameter of fine cellulose fibers of 1 μm to 300 μm, and a fine cellulose fiber concentration of 0.01% by weight to 1.0% by weight Prepare as is. The average dispersion diameter (hereinafter referred to as Rv) of the fine cellulose fibers in the papermaking dispersion must be 1 μm or more from the viewpoint of water permeability and papermaking efficiency, and 300 μm or less from the viewpoint of the uniformity of the nonwoven fabric. It is necessary to be. The dispersion average diameter (Rv) as used herein refers to a dispersion for papermaking using a laser scattering particle size distribution measuring device (manufactured by Horiba, Ltd., laser diffraction / scattering particle size distribution measuring device LA-920, the lower limit detection value is 0). 0.02 μm) means a volume average arithmetic average diameter obtained by measurement at room temperature. In this measurement, the arithmetic average diameter related to the volume distribution is used according to Mie's scattering theory, and the relative refractive index of the cellulose used in this case with respect to the refractive index of water is 1.20 (see Non-Patent Document 6).

When the Rv of the papermaking dispersion is preferably in the range of 3 μm or more and 200 μm or less, and more preferably 5 μm or more and 100 μm or less, the nonwoven fabric of the present invention can be provided with better uniformity.
The concentration of fine cellulose fibers in the papermaking dispersion during papermaking is 0.01 wt% or more and 1.0 wt% or less, preferably 0.05 wt% or less and 0.5 wt% or less, more preferably It is 0.1 wt% or more and 0.4 wt% or less. From the viewpoint of ensuring the stability of the dispersion, the fine cellulose fiber concentration in the papermaking dispersion is preferably 0.01% by weight or more. It is preferable that the fine cellulose fiber concentration is 0.1% by weight or more because the fine cellulose fiber layer and the water separation layer are difficult to separate in the dispersion. The fine cellulose fiber concentration is preferably 1.0% by weight or less from the viewpoint of the viscosity of the dispersion. When the content is 1.0% by weight or less, the viscosity of the dispersion is not too high, and uniform papermaking can be performed.

Next, as a filter cloth at the time of papermaking, from the viewpoint of avoiding a decrease in yield of the nonwoven fabric due to the passage of fine cellulose fibers through the filter cloth and avoiding a decrease in productivity due to a decrease in water permeability, a dispersion for papermaking A filter cloth having the ability to filter 95% or more of fine cellulose fibers by filtration at 25 ° C. under atmospheric pressure and having a water permeation amount of 0.005 cc / cm ² · s or more at 25 ° C. under atmospheric pressure. Is preferably used. The filter cloth is placed on the wire of the paper making apparatus, and the paper dispersion is filtered on the filter cloth to deposit fine cellulose fibers on the filter cloth for paper making. A wet nonwoven fabric (wet paper) First make. In particular, the strength of the wet paper is important in terms of paper feeding in the continuous film forming process. Therefore, it is important to control the solid content concentration in the wet paper that most affects the wet paper strength to an appropriate range. is there. The solid content concentration of fine cellulose fibers in the wet paper is preferably 4% by weight to 30% by weight, more preferably 8% by weight to 25% by weight, and particularly preferably 10% by weight to 20% by weight. A wet nonwoven fabric (wet paper) is produced. The solid content concentration of the wet paper at this time is preferably 40% by weight or less from the viewpoint of controlling the porosity in the drying step. It is also possible to continuously wind up the nonwoven fabric of the present invention in the form of a roll by peeling the nonwoven fabric from the filter cloth described above before or after the drying step.

  Here, the filter cloth having the ability to filter out 95% or more by filtration at 25 ° C. under atmospheric pressure satisfies the following conditions. That is, on a coarse cylindrical funnel type or buchner funnel glass filter (for example, Buchner funnel glass filter, 25G manufactured by Shibata Kagaku Co., Ltd.) having a pore size of 100 μm or more and an outer diameter in the range of 100 to 125 μm. The filter cloth to be applied is attached in a wet state, and a filtration test under atmospheric pressure of the paper dispersion of the present invention is performed. At this time, the content of fine cellulose fibers contained in the filtrate is measured by a drying method or the like, and as a filtration rate (the fine cellulose content before filtration in the papermaking dispersion used in the filtration experiment-included in the filtrate When the value of (fine cellulose content) × 100 / (fine cellulose content before filtration in the papermaking dispersion used in the filtration experiment) (%) was calculated, this value was 95% or more, preferably 98 % Membrane, nonwoven fabric, woven fabric, glass nonwoven fabric, metal mesh and the like.

Moreover, it is preferable that this filter cloth can pass water easily at the time of the filtration test on the conditions mentioned above. That is, it is preferable permeation amount of water under 25 ° C. atmospheric pressure is less than 0.005cc / cm ² · s or more 0.300cc / cm ² · s. If the amount of transmitted 0.005cc / cm ² · s or more 0.300cc / cm ² · s or less of water, the resistance is extremely small when the dispersion medium passes through the filter cloth, it takes much time for paper making It is preferable from the viewpoint of productivity. This is particularly important during continuous papermaking as described below.
Among filter cloths satisfying such conditions, the filter cloth used in the present invention is preferably a nonwoven fabric or woven fabric made of organic polymer fibers, or a porous film made of organic polymers. Furthermore, in the type of organic polymer, polyethylene terephthalate (PET), polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyvinyl chloride, and the like as fine cellulose fibers used in the present invention such as cellulose. Non-cellulose general-purpose organic polymers such as vinylidene, polyvinylidene fluoride, nylon-6,6, and nylon-6 are preferred.

The shape of the filter cloth may be a non-woven fabric, a woven fabric, or a porous membrane as long as it satisfies the above filterability conditions. Since these selections are related to the peelability from the filter cloth when the non-woven fabric containing microporous cellulose is peeled from the filter cloth after papermaking, it greatly contributes to the uniformity of the thickness distribution of the product. is important. For example, when the non-woven cloth containing the microporous cellulose of the present invention is peeled off from the filter cloth after drying, the ease of peeling of the cellulose from the filter cloth becomes a problem.
As described above, since the performance required for the filter cloth used in the present invention is filterability (fine cellulose fiber) and permeability (dispersion medium), the pore diameter (through hole diameter) of the filter cloth is an important factor. However, there are various shapes that can be used as a filter cloth, and in addition, since part of the filter cloth material swells in a dispersion medium environment centering on the aqueous system used in the present invention, the pore diameter of the filter cloth measured under drying and Often different from the actual pore size. Since various materials can be allowed, it is not possible to simply limit the appropriate pore size.

  Examples of the filter cloth that can be used in the present invention include a PET 460 screen mesh and a plain fabric made of PET / nylon blend (Shikishima Canvas, NT20). For example, in the case of a 460 screen mesh made of PET, the pore diameter is approximately 20 μm × 20 μm. The filter cloth has a filtration rate of fine cellulose fibers of almost 100% depending on conditions, even though fibers smaller than 20 μm are also included in the dispersion in Rv smaller than 20 μm. This is considered to be due to the fact that fibers having a small particle size are absorbed by the fiber assembly during the paper making process, and the concentration thereof is increased by filtration while growing.

Furthermore, the nonwoven fabric (a) containing the cellulose used by this invention can control the porosity of the nonwoven fabric obtained by selecting a drying method suitably with respect to the wet paper obtained at the said process, for example.
Although this invention does not specifically limit the drying method of the wet paper obtained at the said process, the following method can be mentioned as an example. When wet paper containing water as a dispersion medium is directly attached to a metal surface like a drum dryer and dried, a nonwoven fabric containing cellulose having a porosity of about 35% or more and about 65% or less is obtained. Can do.
By replacing the water in the wet paper with an organic solvent or an organic solvent / water mixed solution and then drying, a nonwoven fabric having a higher porosity than that obtained by drying with a drum dryer can be obtained. Although it depends on the conditions, according to the drying method, a nonwoven fabric having a porosity of about 60% to about 95% can be obtained. Furthermore, a nonwoven fabric having a high porosity of about 70% or more and about 95% or less can also be obtained by freeze-drying wet paper using water as a medium. By appropriately selecting these drying methods and more detailed conditions (drying temperature, type of organic solvent to be substituted, etc.), the porosity can be designed within the preferred range of the present invention.

Moreover, as an organic solvent used in this case, an organic solvent having a relative dielectric constant of 3 or less, which is a low polarity hydrophobic solvent such as an aliphatic hydrocarbon, a cyclic hydrocarbon, an aromatic hydrocarbon, or a halogenated hydrocarbon. It can be used suitably. More specifically, cyclohexane, toluene, carbon tetrachloride and the like are extremely effective and suitable for making a microporous nonwoven fabric having a certain range of air permeability provided by the present invention. In particular, when the solvent contained in the wet paper is water and is replaced with an organic solvent that does not dissolve in water such as cyclohexane or toluene, for example, water such as acetone, methyl ethyl ketone, iso-propyl alcohol, or iso-butyl alcohol is used. A two-stage substitution method is also effective in which substitution is first performed with a dissolving organic solvent and then substitution is performed with a water-insoluble solvent such as cyclohexane or toluene. The solvent used at this time may be a mixed solvent with water or a mixed solvent of organic solvents.
Furthermore, it is extremely effective in obtaining a non-woven fabric having a high porosity even by substituting one or more organic solvents having a certain degree of solubility in water or a mixed solution of one or more organic solvents and water as a substitution solvent. is there.

  Examples of such organic solvents include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol and other alkyl alcohols having 1 to 4 carbon atoms, dimethylformamide, dimethyl Amide solvents such as acetamide, ketones such as acetone, methyl ethyl ketone, diacetone alcohol or keto alcohols, ethers such as tetrahydrofuran, dioxane, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexane Alkylene glycols containing 2-6 carbon atoms, such as triol, thiodiglycol, hexylene glycol, diethylene glycol, ethylene glycol Cellosolves such as monomethyl ether and ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol n-butyl ether, carbitols such as triethylene glycol n-butyl ether, propylene Others such as glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, 2-isopropoxyethanol, 2-butoxyethanol, 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate Glycol derivatives of 1,2-hexanediol, 1,2-o 1,2-alkyldiols such as tandiol, polyethylene glycol, polypropylene glycol, glycerin and derivatives thereof, 3-methoxy-1-propanol, 3-methoxy-1-butanol, N-methyl-2-pyrrolidone, 2 -Pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and the like can be mentioned, but are not limited thereto. If the organic solvent as described above is contained in the nonwoven fabric containing the medium immediately before drying, a nonwoven fabric having a high porosity can be obtained. What is necessary is just to select the timing of injection | throwing-in of the organic solvent in a manufacturing process according to the objective.

Further, when forming the nonwoven fabric (a) containing cellulose by the papermaking method, the flame retardant (c) may be added to the dispersion for papermaking, Since it is discharged out of the system, the yield becomes poor as a method of addition, and in some cases a recovery step is required. Therefore, the flame retardant (c) is added to the substitution solvent in the substitution step with the organic solvent described above. Is more preferable in terms of efficiency.
The resin (b) other than cellulose in the present invention is at least one resin selected from thermoplastic resins, thermosetting resins, photocurable resins, and resin cured products.
As thermoplastic resins, styrene resins, acrylic resins, aromatic polycarbonate resins, aliphatic polycarbonate resins, aromatic polyester resins, aliphatic polyester resins, aliphatic polyolefin resins, cyclic olefin resins, polyamide resins Examples thereof include resins, polyphenylene ether resins, thermoplastic polyimide resins, polyacetal resins, polysulfone resins, and amorphous fluorine resins.

  Styrenic resin refers to homopolymers of vinyl aromatic monomers or copolymers with other monomers, and examples of vinyl aromatic monomers include styrene, α-methylstyrene, paramethylstyrene, and the like. Among them, a styrene homopolymer or a copolymer with another monomer is preferable. In the case of a homopolymer, it may be one having a stereoregularity in the chain (isotropy, syndiotactic) or one (atactic). Examples of other copolymerizable monomers include acrylonitrile, methacrylonitrile, isoprene, butadiene, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, and vinyl acetate. Resins obtained by copolymerizing with styrene resin monomers, such as acrylonitrile-styrene copolymer and styrene-methacrylic acid copolymer, can adjust the refractive index of the resin by the copolymerization ratio. This is preferable because it is possible. For example, when a monomer of polystyrene (refractive index, about 1.59) and a monomer of polyacrylonitrile (refractive index of about 1.52) are copolymerized at 71:21, a resin having a refractive index of about 1.57 is obtained. And can be suitably used as a resin (b) other than cellulose of the present invention. Examples of the copolymerization form include block copolymerization, random copolymerization, and graft copolymerization.

  Acrylic resins are methacrylic acid esters such as cyclohexyl methacrylate, t-butyl cyclohexyl methacrylate, and methyl methacrylate, and acrylics such as methyl acrylate, ethyl acrylate, butyl acrylate, isopropyl acrylate, and 2-ethylhexyl acrylate. One or more monomers selected from acid esters are polymerized. Of these, a homopolymer of methyl methacrylate or a copolymer with other monomers is preferable. Examples of monomers copolymerizable with methyl methacrylate include other alkyl methallylic esters, alkyl acrylates, aromatic vinyl compounds such as styrene, vinyl toluene and α-methyl styrene, acrylonitrile, methacrylonitrile and the like. Mention may be made of vinyl cyanides, maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide, unsaturated carboxylic acid anhydrides such as maleic anhydride, and unsaturated acids such as acrylic acid, methacrylic acid and maleic acid. Moreover, alicyclic acrylic resins, such as tricyclodecyl methacrylate, are also mentioned.

  The aromatic polycarbonate resin is an aromatic polycarbonate derived from an aromatic dihydroxy compound. Examples of the aromatic dihydroxy compound include 1,1-bis (4-hydroxy-t-butylphenyl) propane, 2, Bis (hydroxyaryl) alkanes such as 2-bis (4-hydroxyphenyl) propane, bis (1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, etc. Hydroxyaryl) cycloalkanes, 4,4'-dihydroxydiphenyl ether, dihydroxyaryl ethers such as 4,4'-dihydroxy-3,3'-dimethylphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4 ' -Dihydroxy-3,3'-dimethyl Dihydroxyaryl sulfides such as phenyl sulfide, dihydroxyaryl sulfoxides such as 4,4′-dihydroxydiphenyl sulfoxide, 4,4′-dihydroxy-3,3′-dimethylphenyl sulfoxide, 4,4′-dihydroxydiphenyl sulfone, 4 , 4'-dihydroxy-3,3'-dimethylphenylsulfone, and the like. Among these, 2,2-bis (4-hydroxyphenyl) propane (common name, bisphenol A) is particularly preferable. These aromatic dihydroxy compounds can be used alone or in combination of two or more.

The aromatic polyester-based resin is not particularly limited, but specific examples include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polyarylate, and the like.
Examples of the aliphatic polyester-based resin include a polymer mainly composed of aliphatic hydroxycarboxylic acid and a polymer mainly composed of aliphatic polycarboxylic acid and aliphatic polyhydric alcohol. Specifically, polymers having aliphatic hydroxycarboxylic acid as the main component include polyglycolic acid, polylactic acid, poly-3-hydroxybutyric acid, poly-4-hydroxybutyric acid, poly-4-hydroxyvaleric acid, poly-3- Hydroxyhexanoic acid or polycaprolactone, etc. are mentioned. Polymers mainly composed of aliphatic polycarboxylic acid and aliphatic polyhydric alcohol include polyethylene adipate, polyethylene succinate, polybutylene adipate, or polybutylene succinate. Is mentioned.

Aliphatic polyolefin resins include polyethylene, polypropylene, ethylene propylene copolymer, polymethylpentene, polybutene, ethylene vinyl acetate copolymer, ionomer (ethylene acrylic acid polymer salt, styrene sulfonate, etc.) resin, and Examples thereof include copolymers thereof and modified products of maleic acid.
The cyclic olefin-based resin is a polymer containing a cyclic olefin skeleton in a polymer chain, such as nobornene or cyclohexadiene, or a copolymer containing these, and the production method thereof is not particularly limited. The cyclic olefin-based resin includes, for example, a norbornene-based repeating unit of a norbornene skeleton, or a norbornene-based resin composed of a copolymer of a norbornene skeleton and a methylene skeleton. “Zeonoa”, “Appel” manufactured by Mitsui Chemicals, and “Topas” manufactured by Chicona. Specific examples include JP-A-62-252406, JP-A-62-2252407, JP-A-2-133413, JP-A-63-145324, JP-A-63-264626, Japanese Laid-Open Patent Publication No. 1-2240517, Japanese Patent Publication No. 57-8815, Japanese Laid-Open Patent Publication No. 5-39403, Japanese Laid-Open Patent Publication No. 5-43663, Japanese Laid-Open Patent Publication No. 5-43834, Japanese Laid-Open Patent Publication No. 5-70655, Japanese Laid-open Patent Publication No. -279554, JP-A-6-206985, JP-A-7-62028, JP-A-8-176411, JP-A-9-241484, and the like.

  The polyamide resin is not particularly limited as long as it is a known polyamide resin. For example, polycaprolactam (nylon 6), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebamide (nylon 610), polyhexamethylene dodecamide (nylon 612) ), Polyundecamethylene adipamide (nylon 116), polyundecalactam (nylon 11), polydodecalactam (nylon 12), polytrimethylhexamethylene terephthalamide (nylon TMHT), polyhexamethylene isophthalamide (nylon 6I) ), Polynonanemethylene terephthalamide (9T), polyhexamethylene terephthalamide (6T), polybis (4-aminocyclohexyl) methane dodecamide (nylon PACM12), polybis (3-methyl-amino) Chlorhexyl) methane dodecamide (nylon dimethyl PACM12), polymetaxylylene adipamide (nylon MXD6), polyundecamethylene hexahydroterephthalamide (nylon 11T (H)), polydodecane terephthalamide (nylon 12T), and these Of these, polyamide copolymers containing at least two different polyamide-forming components, and mixtures thereof.

  Examples of the polyphenylene ether resin include poly (2,6-dimethyl-1,4-phenylene ether), poly (2-methyl-6-ethyl-1,4-phenylene ether), and poly (2-methyl-6). -Phenyl-1,4-phenylene ether), poly (2,6-dichloro-1,4-phenylene ether) and the like, and further copolymers of 2,6-dimethylphenol and other phenols (for example, And polyphenylene ether copolymers such as copolymers with 2,3,6-trimethylphenol and copolymers with 2-methyl-6-butylphenol as described in JP-B-52-17880. Can be mentioned. Among these, particularly preferred polyphenylene ethers include poly (2,6-dimethyl-1,4-phenylene ether), a copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol, or these It is a mixture. In addition, the polyphenylene ether resin that can be used in the present invention may be a polyphenylene ether modified in whole or in part. The modified polyphenylene ether here means at least one carbon-carbon double bond or triple bond and at least one carboxylic acid group, acid anhydride group, amino group, hydroxyl group, or glycidyl in the molecular structure. The polyphenylene ether modified with at least one modifying compound having a group. Since the polyphenylene ether resin has high heat resistance and excellent electrical characteristics, it can be suitably used for high heat resistance applications and electronic parts.

The monomer in the present invention refers to a monomer constituting these thermoplastic resins.
The number average molecular weight of these thermoplastic resins is generally 1000 or more, preferably 5000 or more and 5 million or less, and more preferably 10,000 or more and 1 million or less. Especially when impregnated with thermoplastic resin monomers and combined by polymerization, the addition of monomers that form a crosslinked structure with other thermoplastic resin monomers such as divinylbenzene also suppresses plasticity at high temperatures. It is extremely effective from the viewpoint of
These thermoplastic resins can be used alone or in admixture of two or more. In the case of using a mixture of two or more thermoplastic resins, it is preferable because the refractive index of the resin can be adjusted by the mixing ratio. A resin obtained by blending an acrylic resin and a styrene resin is preferable. For example, polymethyl methacrylate (refractive index: about 1.49) and acrylonitrile styrene (acrylonitrile content: about 21%, refractive index: about 1.57). When mixed at 50:50, a resin having a refractive index of about 1.53 is obtained, and can be suitably used as a resin (b) other than cellulose of the present invention.

The thermosetting resin and photocurable resin used in the present invention mean a relatively low molecular weight substance that is liquid, semi-solid or solid at room temperature and exhibits fluidity at room temperature or under heating. To do. These can be an insoluble and infusible resin formed by forming a network-like three-dimensional structure while increasing the molecular weight by causing a curing reaction or a crosslinking reaction by the action of a curing agent, a catalyst, heat or light. In addition, the cured resin in the present invention means a resin obtained by curing the thermosetting resin or the photocurable resin.
The thermosetting resin used in the present invention is not particularly limited, but specific examples include epoxy resin, thermosetting modified polyphenylene ether resin, thermosetting polyimide resin, urea resin, allyl resin, Silicon resin, benzoxazine resin, phenol resin, unsaturated polyester resin, bismaleimide triazine resin, alkyd resin, furan resin, melamine resin, polyurethane resin, aniline resin, and other industrially available resins and these resins 2 or more The resin obtained by mixing is mentioned. Among these, epoxy resins, allyl resins, unsaturated polyester resins, vinyl ester resins, thermosetting polyimide resins, and the like are suitable for use as optical materials because they have transparency.

  The epoxy resin refers to an organic compound having at least one epoxy group. The number of epoxy groups in the epoxy resin is preferably 1 or more and 7 or less per molecule, and more preferably 2 or more per molecule. Here, the number of epoxy groups per molecule is determined by dividing the total number of epoxy groups in the epoxy resin by the total number of molecules in the epoxy resin. It does not specifically limit as said epoxy resin, A conventionally well-known epoxy resin can be used, For example, the epoxy resin etc. which were shown below are mentioned. These epoxy resins may be used independently and 2 or more types may be used together. These epoxy resins are thermosetting resin precursor epoxy compounds, and by using a curing agent, a cured epoxy resin that is a cured product of the epoxy resin can be obtained.

  For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol type epoxy resin such as bisphenol S type epoxy resin, phenol novolac type epoxy resin, novolak type epoxy resin such as cresol novolak type epoxy resin, Aromatic epoxy resins such as trisphenol methane triglycidyl ether and their water additives and bromides can be mentioned. Also, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-2-methylcyclohexylmethyl-3,4-epoxy-2-methylcyclohexanecarboxylate, bis (3,4 -Epoxycyclohexyl) adipate, bis (3,4-epoxycyclohexylmethyl adipate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3 , 4-epoxycyclohexanone-meta-dioxane, alicyclic epoxy resins such as bis (2,3-epoxycyclopentyl) ether, and the like.

  Also, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether Aliphatic epoxy resins such as glycidyl ethers, polyglycidyl ethers of long-chain polyols containing polyoxyalkylene glycols or polytetramethylene ether glycols containing 2 to 9 (preferably 2 to 4) carbon atoms alkylene groups, etc. It is done. In addition, glycidyl ester type epoxies such as phthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, diglycidyl-p-oxybenzoic acid, glycidyl ether-glycidyl ester of salicylic acid, dimer acid glycidyl ester, etc. Examples thereof include resins and hydrogenated products thereof. Also, triglycidyl isocyanurate, N, N′-diglycidyl derivative of cyclic alkylene urea, N, N, O-triglycidyl derivative of p-aminophenol, N, N, O-triglycidyl derivative of m-aminophenol, etc. Examples thereof include glycidylamine type epoxy resins and hydrogenated products thereof. Moreover, the copolymer etc. of radical polymerizable monomers, such as glycidyl (meth) acrylate, ethylene, vinyl acetate, (meth) acrylic acid ester, etc. are mentioned.

  In the present invention, (meth) acryl means acryl or methacryl. In addition, a polymer mainly composed of a conjugated diene compound such as epoxidized polybutadiene or a partially hydrogenated polymer obtained by epoxidizing an unsaturated carbon double bond may be used. Also, a polymer block mainly composed of a vinyl aromatic compound, such as epoxidized SBS, and a polymer block mainly composed of a conjugated diene compound or a partially hydrogenated polymer block thereof are contained in the same molecule. Examples of the block copolymer include epoxidized unsaturated carbon double bonds of a conjugated diene compound. Moreover, the polyester resin etc. which have 1 or more per molecule, Preferably 2 or more epoxy groups are mentioned. Examples thereof include urethane-modified epoxy resins and polycaprolactone-modified epoxy resins in which urethane bonds and polycaprolactone bonds are introduced into the structure of the epoxy resin. Examples of the modified epoxy resin include a rubber modified epoxy resin in which a rubber component such as NBR, CTBN, polybutadiene, and acrylic rubber is contained in the epoxy resin. In addition to the epoxy resin, a resin or oligomer having at least one oxirane ring may be added.

Moreover, the thermosetting resin and composition containing a fluorene group, such as a fluorene containing epoxy resin, a fluorene containing acrylate resin, a fluorene containing epoxy acrylate resin, or its hardened | cured material is also mentioned. These fluorene-containing epoxy resins are suitably used because they contain a fluorene group in the molecule and thus have a high refractive index and high heat resistance.
The curing agent used for the curing reaction of the epoxy resin is not particularly limited, and conventionally known curing agents for epoxy resins can be used. For example, amine compounds, compounds such as polyaminoamide compounds synthesized from amine compounds, A tertiary amine compound, an imidazole compound, a hydrazide compound, a melamine compound, an acid anhydride, a phenol compound, a thermal latent cationic polymerization catalyst, a photolatent cationic polymerization initiator, dicyanamide, and derivatives thereof may be mentioned. These hardening | curing agents may be used independently and 2 or more types may be used together.

Moreover, as a photocurable resin used in this invention, the epoxy resin containing a latent photocationic polymerization initiator etc. are mentioned, for example. These thermosetting resins or photocurable resins may be used alone or in combination of two or more.
In addition, when hardening the said photocurable resin, you may apply heat simultaneously with light irradiation. In the present invention, the curing agent and curing catalyst used in combination with the thermosetting resin and the photocurable resin are not particularly limited as long as they are used for curing the thermosetting resin and the photocurable resin. Specific examples of the curing agent include polyfunctional amines, polyamides, acid anhydrides, and phenol resins. Specific examples of the curing catalyst include imidazole. These may be used alone or as a mixture of two or more. it can.

  The polyimide resin in the present invention is not particularly limited, but is a resin containing an imide group in the main chain skeleton, and any of thermoplastic and thermosetting polyimide resins can be used. Specifically, polyimide, polyamide imide, polyether imide, polyester imide, polysiloxane imide and the like can be mentioned, and specific examples include Japanese Patent No. 2218568, Japanese Patent No. 2129731, Japanese Patent No. 2738453, Japanese Patent No. 2746555, Japanese Patent No. 2909844, Japanese Patent No. 3034838, Japanese Patent No. 1531563, Japanese Patent No. 1836437, Japanese Patent No. 2597214, Japanese Patent No. 25597215, Japanese Patent No. 2671162, Japanese Patent No. 1954076, Japanese Patent No. 2034676, Japanese Patent No. 2514313, It is described in Japanese Patent No. 2587810, Japanese Patent No. 2523682, Japanese Patent No. 2566250, Japanese Patent No. 2566251, and the like.

Moreover, resin obtained by mixing 2 or more types of thermoplastic resins, thermosetting resins, photocurable resins, and resin cured products can also be used.
The flame retardant (c) contained in the composite of the present invention provides further flame retardancy and discoloration resistance when the composite of the present invention is exposed to high temperature conditions (for example, 250 ° C. to 300 ° C.). Give. The flame retardant introduced in Non-Patent Document 7 is effective for imparting flame retardancy of the present composite. For example, a halogen flame retardant that traps radicals, and a phosphorus system that promotes the formation of a carbonized film on the surface. Flame retardants and metal salt flame retardants, nitrogen flame retardants that generate non-flammable gases during combustion, and hydrate flame retardants that produce a cooling effect by desorption of water molecules in high temperature environments Fibrous flame retardant that has an effect of cutting off the combustion cycle by suppressing the internal diffusion of the decomposition product, and the low melting point component starts to melt under high temperature conditions, and encapsulates the combustion product In addition to low-melting glass flame retardant that blocks oxygen, silicone flame retardant, other ammonium salts such as ammonium phosphate, ammonium sulfamate, ammonium sulfate, ammonium borate, metal oxide, metal powder, C acid salt, can be exemplified inorganic flame retardants such as carbonates.

Among the above-mentioned flame retardants, hydrate-based flame retardants and low-melting glass-based flame retardants are preferable because they are excellent in terms of discoloration resistance.
Hydrated flame retardants include water such as aluminum hydroxide, calcium hydroxide, dolomide, hydrotalcite, calcium hydroxide, barium hydroxide, basic magnesium carbonate, zirconium hydroxide, tin oxide hydrate. Examples include Japanese metal flame retardants and boric acid. Of these, aluminum hydroxide, boric acid, and boric acid compounds are preferable, and boric acid and boric acid compounds are particularly preferably used. Boric acid can be esterified with a hydroxyl group of cellulose to become cellulose borate. However, as with other flame retardants, boric acid is effective even if it is simply immobilized on the cellulose surface.

The low melting point glass has a glass transition point in a temperature range of about 100 ° C. to 500 ° C., and includes SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , P ₂ O ₅ , Na ₂ O, K ₂ O, Li ₂ O. , CaO, BaO, ZnO, Sb ₂ O ₃ , ZrO ₂ , TiO ₂ and other metal oxides, ammonium phosphate, tin halide, lead borosilicate inorganic compounds and SiO ₂ —MgO—H ₂ O system, PbO -B ₂ O _{3 system, ZnO-P} 2 O 5 _{-MgO-based, P 2 O 5 -B 2 O} 3 -PbO-MgO -based, _{P-Sn-O-F-based, PbO-V 2 O 5 -TeO} 2 Hydrated glass, etc. of the system. In particular, it is preferable that the low-melting glass softens and coats the cellulose fiber under the high temperature conditions exposed by the present mixture. For example, when the maximum exposure temperature of the present mixture is 300 ° C., the glass transition point is 300 ° C. or lower. Is preferable, more preferably 250 ° C. or lower, and most preferably 200 ° C. or lower.

Further, a halogenated resin (b) other than cellulose, such as a halogenated epoxy resin, is preferably employed as the resin (b) other than cellulose and the flame retardant (c).
In the present invention, the non-woven fabric (a) component containing cellulose is 0.1 wt% or more and 99 wt% or less, and the resin (b) component other than cellulose is difficult to be 1 wt% or more and 99.8 wt% or less. The flame retardant (c) component is 0.01 wt% or more and 50 wt% or less. From the viewpoint of water absorption, the component (a) must be 99% by weight or less, and the component (b) must be 1% by weight or more. From the viewpoint of linear expansion coefficient and heat resistance, the component (a) is 0.1% by weight or more, The component (b) needs to be 99.8% by weight or less. A preferred range is that the component (a) is 0.2 wt% or more and 80 wt% or less, and the component (b) is 20 wt% or more and 99.8 wt% or less. More preferable range is that the component (a) is 10% or more and less than 60% by weight, and the component (b) is more than 40% by weight and 90% by weight or less. Particularly preferable ranges are (a) component of more than 10% by weight and 50% by weight or less, and (b) component of 50% by weight or more and less than 90% by weight. The resin content can be obtained from the weight of the cellulose nonwoven fabric before impregnation with the resin and the weight of the composite after impregnation, and can also be obtained from the weight of the remaining cellulose nonwoven fabric by removing only the resin with a soluble solvent. As other methods, there are a method of obtaining from the specific gravity of the resin and the specific gravity of cellulose, and a method of obtaining by quantitatively determining the functional groups of the resin and cellulose using NMR and IR.

The content of the flame retardant (c) is preferably 0.1% by weight or more, more preferably 1% by weight or more, and most preferably 3% by weight or more from discoloration resistance and flame retardancy. 30% by weight or less is preferable, more preferably 20% by weight or less, and most preferably 15% by weight or less. In particular, in the blending of the flame retardant (c) of the present invention, it is important to consider that the presence of the flame retardant contributes to the improvement of heat resistance for all blended components.
For example, boric acid, which is a flame retardant, functions extremely effectively against cellulose. As described above, the non-woven fabric (a) containing cellulose is coated and fixed in advance so as to be localized in the vicinity of cellulose. It is effective to compound the resin after it has been converted into a resin, but in a compounding method in which boric acid is dispersed and mixed inside the resin, boric acid may discolor and deteriorate the resin at a high temperature depending on the resin. Therefore, in such a case, it is necessary to select a resin particularly excellent in acid resistance.

The glass transition temperature of the resin (b) other than cellulose is preferably 50 ° C. or higher, more preferably 100 ° C. or higher, and particularly preferably 150 ° C. or higher. From the viewpoint of heat resistance of the composite, the glass transition temperature is desirably 50 ° C. or higher.
In the present invention, it is preferable that the total light transmittance of a 100 μm molded product of the resin (b) other than cellulose is 70% or more. When it is 70% or more, the transparency of the composite is improved, which is preferable. More preferably, it is 80% or more, and particularly preferably 85%.
In the present invention, the refractive index of the resin (b) other than cellulose is preferably more than 1.48 and less than 1.62. More preferably, it is 1.50 or more and 1.61 or less, Most preferably, it is 1.52 or more and 1.60 or less. Within this range, the difference from the refractive index of the cellulose used for the component (a) is small, so that the transparency of the composite is further improved, which is preferable. In order to bring the refractive index of the resin (b) other than cellulose close to the refractive index of cellulose as the component (a), two or more kinds of resin monomers are copolymerized, and the refractive index is adjusted and used. It is also very effective to adjust the refractive index by blending two or more kinds of resins. In addition, it is preferable that two or more types of resins to be used are compatible because transparency is improved. A combination of compatible resins is not particularly limited, and examples thereof include a polymethyl methacrylate / styrene-acrylonitrile copolymer blend.

It is also very effective to control the refractive index as a component (b) by a combination of a thermosetting resin or photocurable resin, a curing agent and a curing accelerator. In this case, two or more kinds of resins, curing agents, and curing accelerators can be used. For example, although not particularly limited, it is effective to adjust the refractive index by mixing a bisphenol A type epoxy resin and a hydrogenated bisphenol A type epoxy resin. As the component (b), an organic-inorganic hybrid material obtained by hybridizing a thermosetting resin and a photocurable resin with a metal alkoxide such as silica, titanium, or zinc is also very effective for controlling the refractive index.
In the present invention, the Abbe number of the resin (b) other than cellulose is preferably 30 or more and 70 or less, more preferably 40 or more and 60 or less. If it is within this range, the refractive index wavelength dependency of the resin (b) other than cellulose becomes small, which is preferable because the transparency of the composite is further improved. The Abbe number (υd) here indicates the wavelength dependence of the refractive index, that is, the degree of dispersion, and can be obtained by υd = (nD−1) / (nF−nC). Here, nC, nD, and nF are refractive indices with respect to the C-line (wavelength 656 nm), D-line (589 nm), and F-line (486 nm) of the Brownhofer line, respectively. The refractive index of a material having a small Abbe number varies greatly depending on the wavelength.

Although the flame retardant (c) also depends on the amount added, it is preferable for the same reason that the refractive index and Abbe number of the resin (b) other than cellulose are in the preferred range.
The preferable in-plane retardation (Re) value of the composite obtained in the present invention at a wavelength of 550 nm is 50 nm or less per 100 μm thickness, more preferably 40 nm or less, and particularly preferably 30 nm or less.
The retardation of the composite of the present invention is preferably 350 nm or less, more preferably 200 nm or less, and particularly preferably 100 nm or less. Within this range, it can be preferably used as an optical material such as a display display substrate.

  By controlling Re within a preferred range, the viewing angle characteristics are excellent when used in a liquid crystal display device or the like. At present, polycarbonate films and polyphenylene ether films, which are plastic films that have been studied, have a problem in that the range of use is limited because the in-plane retardation tends to increase at the film forming stage. In the composite of the present invention, by using a nonwoven fabric (a) containing cellulose in which cellulose fibers having a fiber diameter of up to 1500 nm or less are irregularly arranged in the plane direction and impregnating a resin (b) other than cellulose. In order to manufacture, in-plane retardation (Re) can be controlled in a preferable range.

The photoelastic coefficient is described in various documents (see, for example, Non-Patent Document 8), and is defined by the following equation.
| CR | = | Δn | / σR | Δn | = | n1-n2 |
(Where: | CR |: absolute value of photoelastic coefficient, σR: stretching stress, | Δn |: absolute value of birefringence, n1: refractive index in stretching direction, n2: refractive index perpendicular to stretching direction)
The closer the value of the photoelastic coefficient is to zero, the smaller the change in birefringence due to external force, which means that the change in birefringence designed for each application is small.
The composite obtained by the present invention preferably has an absolute value of the photoelastic coefficient of 80 × 10 ⁻¹² / Pa or less. More preferably, it is 50 * 10 < ^-12 > / Pa or less, More preferably, it is 20 * 10 < ^-12 > / Pa or less. If the photoelastic coefficient is within this range, the change in birefringence due to stress is small, so that the contrast and the uniformity of the screen are excellent when used in a liquid crystal display device or the like. The polycarbonate film (photoelastic coefficient 90 × 10 ⁻¹² / Pa), which is currently being investigated, has a large photoelastic coefficient, so that the birefringence tends to increase due to the addition of stress during use. There was a problem that it was. In the composite of the present invention, the nonwoven fabric (a) containing cellulose, in which cellulose fibers having a fiber diameter of up to 1500 nm or less are irregularly arranged in the plane direction, and the absolute value of the photoelastic coefficient of a single resin is The composite value of the resin (b) other than cellulose, which is the preferred range, can control the absolute value of the photoelastic coefficient within the preferred range.

The thickness of the composite in the present invention is preferably 5 μm or more and 5000 μm or less, and the composite having a thickness of 5 μm or more and 5000 μm or less can maintain strength and heat resistance. It is preferable because the thickness and weight of the display used can be reduced. More preferably, they are 20 micrometers or more and 1000 micrometers or less, Most preferably, they are 30 micrometers or more and 400 micrometers or less.
In the present invention, a plurality of composites can be stacked to obtain a composite laminate. The laminate can be thickened by subjecting it to a heat press treatment, and a composite of the present invention having a thickness of 10 μm or more and 5000 μm or less can be obtained. The laminate obtained in this way has high strength, is preferable, and is preferred in terms of contributing mainly to the process efficiency of the composite production because the resin easily permeates as compared with a single-layer body having the same thickness. The number of laminated layers is preferably 2 or more and 30 or less, and more preferably 2 or more and 20 or less. Particularly preferably, the number is 2 or more and 10 or less. When it is 30 or less, a flexible composite can be obtained.

In the present invention, it is preferable that the relationship of the storage elastic modulus in the dynamic viscoelasticity measurement of the composite satisfies the following formula. The storage elastic modulus here means using RSAII manufactured by Rheometrics, the distance between chucks is about 20 to 30 mm, the sample width is about 2 to 4 mm, the measurement frequency is 1 Hz, the amount of strain is 0.05%, and in the tensile mode, This is the storage elastic modulus E ′ of the composite obtained when the temperature is raised from room temperature to 300 ° C. at a rate of 5 ° C. per minute.
1≤E'30 / E'150≤100
Tg: Glass transition temperature of resin (b) other than cellulose E′30: Storage elastic modulus of composite at 30 ° C. E′150: Storage elastic modulus of composite at 150 ° C. More preferably, 1 ≦ E′30 / E '150 ≦ 50, particularly preferably 1 ≦ E′30 / E′150 <25, and most preferably 1 ≦ E′30 / E′150 ≦ 10. The composite of the present invention preferably satisfies the above formula. When it is in this range, it is preferable from the viewpoint of heat resistance, and can be preferably used for an alternative to glass.

Further, it is more preferable that the storage elastic modulus is less decreased even at 250 ° C., and it is more preferable that the following formula is satisfied.
1≤E'30 / E'250≤100
E′250: Storage elastic modulus of the composite at 250 ° C. More preferably, 1 ≦ E′30 / E′250 ≦ 50, particularly preferably 1 ≦ E′30 / E′250 <25, Preferably, 1 ≦ E′30 / E′250 ≦ 10.
In the present invention, in the measurement of the dynamic viscoelasticity of the composite, the storage elastic modulus E′150 at 150 ° C. is preferably 100 MPa or more and 30000 MPa or less. More preferably, it is 400 MPa or more and 20000 MPa or less, Most preferably, it is 1000 MPa or more and 10,000 MPa or less. When it is 100 MPa or more and 30000 MPa or less, it is preferable from a viewpoint of heat resistance and a softness | flexibility, and it can use preferably for the use of glass substitution.

Further, the storage elastic modulus E′250 at 250 ° C. is more preferably 100 MPa or more and 30000 MPa or less. More preferably, it is 400 MPa or more and 20000 MPa or less, Most preferably, it is 1000 MPa or more and 10,000 MPa or less.
“Preferable from the viewpoint of heat resistance” means that the difference in elastic modulus at high temperature and room temperature is small, or that the elastic modulus at high temperature is high. It is preferable because functionalization such as imparting electrical conductivity or imparting gas barrier properties is possible in a simple surface treatment process.
In the present invention, the average linear expansion coefficient of the composite at 50 to 150 ° C. is preferably 0.1 ppm / ° C. or more and 25 ppm / ° C. or less. More preferably, they are 0.1 ppm / degrees C or more and 20 ppm / degrees C or less, Most preferably, they are 0.1 ppm / degrees C or more and 15 ppm / degrees C or less. Furthermore, when the average linear expansion coefficient at 50 to 250 ° C. is 0.1 ppm / ° C. or more and 30 ppm / ° C. or less, more preferably 0.1 ppm / ° C. or more and 20 ppm / ° C. or less, a high heat resistance and low thermal expansion composite The sheet has high industrial utility value (the evaluation method is described in detail in the examples).

  By setting it within this range, it can be preferably used for an alternative to glass. The reason why low linear expansion coefficient is required for resin in glass replacement applications is that the surface-treated conductive function and gas barrier function are destroyed in the process of cooling from the required surface treatment process temperature to room temperature. This is necessary to prevent warpage and deformation due to temperature differences that occur during use. In addition, in applications that are used by bonding to metal, such as a flexible substrate and an electronic substrate, the linear expansion coefficient is preferably the same as that of the metal to be bonded, and the average linear expansion coefficient at 50 to 250 ° C. is 10 ppm / ° C. or more and 20 ppm / It is preferable to set it to below ℃.

In the present invention, the total light transmittance of the composite is preferably 60% or more, more preferably 75% or more, and particularly preferably 85% or more. In order to obtain a composite having a total light transmittance of 60% or more, for example, a resin other than cellulose having a total light transmittance of 60% or more and a refractive index of 1.45 to 1.65 is used. This can be achieved by using a nonwoven fabric (a) containing cellulose having a fiber diameter of 1500 nm or less. When the total light transmittance of the composite is in this range, it can be preferably used as an optical material such as a display display substrate.
In the present invention, the haze value of the composite is preferably 80% or less. More preferably, the haze value is 60% or less, and particularly preferably, the haze value is 50% or less. For example, the average transmittance Tr, av in the above-mentioned toluene of the nonwoven fabric (a) containing cellulose is 0.70 or more, the film quality uniformity parameter H is 0.018 or less, and the maximum fiber diameter of the cellulose is 1500 nm or less. When the refractive index of the component (b) is 1.45 or more and 1.65 or less, the haze value can be made 80% or less. Within this range, it can be preferably used as an optical material such as a display display substrate.

In the present invention, for the nonwoven fabric (a) containing cellulose, as a method of filling and compounding resin (b) other than cellulose,
(1) A method of polymerizing by impregnating a monomer,
(2) A method of impregnating and curing a thermosetting resin precursor or a photocurable resin precursor,
(3) A method of impregnating and drying a solution of resin (b) other than cellulose,
(4) A method of producing a composite by any one of the methods of impregnating a thermoplastic resin melt other than cellulose (b) and cooling after defoaming can be used.
(1) A method of impregnating and polymerizing a monomer means that a monomer such as methyl methacrylate, which is a monomer constituting a thermoplastic resin, is impregnated in a nonwoven fabric (a) containing cellulose, and the monomer is subjected to heat treatment or the like. It is a production method for obtaining a composite comprising a nonwoven fabric (a) containing cellulose and a resin (b) other than cellulose by polymerization, and is used for polymerization of organic peroxides such as peroxides or monomers in general. The polymerization catalyst obtained can be used as a polymerization initiator. When it is assumed that the polymerization catalyst impairs the performance of the composite as an impurity, impregnate a high-purity monomer that does not contain any polymerization inhibitor such as quinones, and perform thermal polymerization without using a polymerization initiator. It is also effective.

  In addition, (2) a method of impregnating and curing a thermosetting resin precursor or a photocurable resin precursor is a mixture of a thermosetting resin precursor such as an epoxy resin or a photocurable resin precursor and a curing agent. In addition to cellulose, the nonwoven fabric (a) containing cellulose is impregnated into the nonwoven fabric (a) containing cellulose, and the thermosetting resin precursor or the photocurable resin precursor is cured by heat treatment or light irradiation. It is a manufacturing method which obtains the composite_body | complex which consists of hardened | cured material of thermosetting resins, such as cured epoxy resin which is resin (b), or hardened | cured material of photocurable resin. When a thermosetting resin precursor such as an epoxy resin or a photocurable resin precursor is solid at room temperature and it is difficult to impregnate the nonwoven fabric (a) containing cellulose, the precursor is heat-treated in advance and melted. It is also possible to impregnate a solution in which the precursor is dissolved in a soluble solvent. In order to increase the smoothness of the surface, it is also effective to allow the reaction to proceed further under heat press treatment when the curing reaction has progressed to some extent. It is also effective at the time of thickening the film (described above) to stack several composites that have undergone a curing reaction to some extent during the heat treatment.

In addition, (3) a method of drying after impregnating a solution of resin (b) other than cellulose is a non-woven fabric containing cellulose by dissolving a thermoplastic resin (b) other than cellulose in a solvent capable of being dissolved. This is a production method in which a resin (b) other than cellulose is combined with a nonwoven fabric (a) containing cellulose by impregnating and drying a).
In addition, (4) a method of impregnating a melt of a thermoplastic resin that is a resin (b) other than cellulose and cooling after defoaming means that the thermoplastic resin that is a resin (b) other than cellulose has a glass transition temperature or higher. A composite comprising a nonwoven fabric (a) containing cellulose and a resin (b) other than cellulose by melting by heating at a melting point or higher, impregnating the nonwoven fabric (a) containing cellulose, cooling after defoaming It is a manufacturing method to obtain. The heat treatment is desirably performed under pressure, and the use of equipment having a vacuum heating press function is effective.

The flame retardant (c) can be combined with the nonwoven fabric (a) which is preferably added to cellulose and contains cellulose in any of the paper making process / dispersion medium replacement process. Moreover, it can add beforehand to resin (b) other than a cellulose, and can be filled and added simultaneously with resin (b) other than a cellulose, and can be set as a composite.
In the present invention, a continuous nonwoven fabric having a thickness of 5 μm or more and 500 μm or less obtained by an artificial film forming method such as a papermaking method or a coating method can be used as the nonwoven fabric (a) containing cellulose. Here, thickness is 5 micrometers or more from a viewpoint of nonwoven fabric strength, Preferably it is 10 micrometers or more, More preferably, it is 20 micrometers. Moreover, it is 500 micrometers or less from the surface of productivity or process control, Preferably it is 300 micrometers, More preferably, it is 200 micrometers or less.

In order to produce a continuous nonwoven fabric, it is essential to perform continuous papermaking or film formation by continuous coating under the above-described conditions. In the case of continuous application, film formation is performed by a continuous film formation process of an application method. For example, a cellulose fiber dispersion is applied onto a traveling support (belt or the like), and this is continuously applied until a drying step. And after drying, the nonwoven fabric is peeled off from the support. The porosity of the nonwoven fabric is controlled by the dispersion medium of the dispersion and the composition of the additive.
In the case of continuous papermaking, the rate of occurrence of paper breakage can be reduced to zero by providing a continuous support between the papermaking process / drying process or between the papermaking process / replacement process / drying process. It is effective. The filter cloth mentioned above can be used effectively as a continuous support here.

  Moreover, the transfer part of each process can also be transferred to the next process using press transfer or a pick-up roll. The support is necessary up to the entry side of the drying process. After drying, the nonwoven fabric is peeled off and wound up. In this case, it is important that the peeling is good. Select the material. Further, it is possible to substitute a filter cloth used in the paper making process as the support. In this case, as described above, after the drying step, the non-woven fabric is peeled off from the papermaking filter cloth as a support and wound. At this time, the good peelability of the filter cloth is important because it greatly affects the quality of the nonwoven fabric. In addition, when the nonwoven fabric and the support are used separately, it is necessary to transfer the wet paper from the filter cloth to the support after performing post-paper pressing, etc. It is good to use.

In the present invention, by using the above-mentioned continuous nonwoven fabric and further impregnating with a monomer, a molten resin or a resin solution in a continuous process, and then polymerizing, curing, or drying, it is also produced as a continuous molded product usually called a roll product. Can do. Obtaining a continuous molded body in this way leads to an improvement in the productivity of the composite, and at the same time it can be adapted to the so-called semi-continuous display device manufacturing process of Roll to Roll, which is extremely meaningful in the industry. is there.
Further, by stacking a plurality of layers of the composite of the present invention, which is a continuous molded body, and continuously or semi-continuously heat-pressing it, it is possible to obtain a continuous molded body laminate having a thickness of 10 μm or more and 5000 μm or less. it can.

Since the composite in the present invention is excellent in optical characteristics such as low linear expansion coefficient, heat resistance, transparency, low haze value, low retardation, etc., liquid crystal display, plasma display, organic EL display, field emission display, rear projection TV, etc. It can be used for a display, a touch panel, a solar cell substrate, a front plate, a color filter substrate, and the like. In particular, the plastic substrate for display using the composite of the present invention can replace the composite of the present invention for the glass application used in these displays, and effects such as weight reduction, flexibility, and resistance to cracking are obtained. It is done.
The composite of the present invention can be subjected to surface functionalization treatment such as transparent conductive treatment, electromagnetic wave shielding treatment, gas barrier treatment, antifouling treatment, and antireflection treatment, for example. For example, when a conductive metal oxide is subjected to a conductive treatment by a method such as vapor deposition or sputtering or metal mesh wiring, metal paste, etc., the composite of the present invention has a thickness of 5 to 500 μm. It can be used as a substrate, for example, a plasma display front electromagnetic wave shield. Moreover, what laminated | stacked the silica by vapor deposition, sputtering, or the oxidation of polysilazane or polysilane, and gave the gas barrier process can be used suitably for the plastic substrate for a display. In addition, a transparent conductive film can be obtained by laminating conductive metal oxides such as ITO and conductive zinc oxide by techniques such as vapor deposition and sputtering, and can be used for touch panels, various display substrates, and solar cell substrates. . As a method for surface treatment of such a composite, the method described in Non-Patent Document 9 can be used. Also by this method, the composite of the present invention can be used as a TFT liquid crystal substrate.

The conductive substrate for transparent electrodes that can be used as a touch panel, various display substrates, or a solar cell substrate using the composite of the present invention can be obtained, for example, as follows. First, a semiconductor film such as an oxide film of indium oxide, tin oxide, tin-indium alloy, zinc oxide-gallium, zinc oxide-aluminum, or a metal film such as gold, silver, palladium, or an alloy thereof on the surface of the transparent substrate A combination of a semiconductor film and a metal film is formed by a known physical deposition method such as a vacuum evaporation method, a sputtering method, or an ion plating method. In order to prevent the performance deterioration of the liquid crystal element, the organic EL element and the like due to the water vapor or oxygen permeating through the transparent substrate as necessary, vapor deposition of a gas barrier layer made of SiO ₂ or the like, or a polysilazane / organic solvent solution, Application of other coating silica materials such as alkoxysilane / organic solvent solution and formation of a barrier layer based on a three-dimensional reaction by heating, application of a polymer having a relatively high gas barrier property such as vinylidene chloride polymer or vinyl alcohol polymer Thus, a gas barrier layer can be provided. The display substrate can be suitably used for production of displays, particularly liquid crystal displays, organic electroluminescence displays, field emission displays, and surface electrolysis displays.

  In the present invention, any additive can be blended according to various purposes within a range that does not significantly impair the effects of the present invention. The type of additive is not particularly limited as long as it is generally used for blending resins and rubber-like polymers. Inorganic fillers, pigments such as iron oxide, stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, ethylene bisstearamide, lubricants, mold release agents, paraffinic process oil, naphthenic process oil, Softeners and plasticizers such as aromatic process oil, paraffin, organic polysiloxane, mineral oil, hindered phenol antioxidants, antioxidants such as phosphorus heat stabilizers, hindered amine light stabilizers, benzotriazoles Examples thereof include ultraviolet absorbers, antistatic agents, reinforcing agents such as organic fibers, glass fibers, carbon fibers, and metal whiskers, coloring agents, other additives, and mixtures thereof.

Hereinafter, the present invention will be described in more detail by way of examples and comparative examples.
Hereinafter, the manufacture example of resin (b) other than the nonwoven fabric (a) containing cellulose used for the Example and cellulose is demonstrated.

[Production Example 1]
Purified Ecuadorian abaca pulp (manufactured by Toho Special Pulp Co., Ltd.) is dispersed in water to 1.5% by weight and subjected to a beating process using a disc refiner (manufactured by Kumagai Riki Co., Ltd., No. 2500-I). Dispersion M1 was obtained by subjecting the slurry to a uniform slurry using a high-pressure homogenizer (NS3015H, manufactured by Niro Soabi (Italy)) under an operating pressure of 100 MPa for 20 times. Next, the dispersion M1 was further diluted with water to a cellulose concentration of 0.20% by weight, subjected to a dispersion treatment for 5 minutes with a home mixer, and the obtained dispersion was used as a papermaking dispersion. . The dispersion average diameter Rv of this papermaking dispersion was measured and found to be 15.4 μm.

  Next, a square woven metal wire using a plain fabric made of PET / nylon blend (made by Shikishima Canvas Co., NT20) having a cellulose filtration rate of 99% or more evaluated using the papermaking dispersion is used below. A paper made using a batch type paper machine (automatic square sheet machine manufactured by Kumagai Riki Kogyo Co., Ltd.) was used as a filter cloth. The above-mentioned filter cloth is placed on a rectangular metal wire (25 cm × 25 cm, the filtration rate of cellulose when the paper dispersion is used; 30% or less) incorporated in the paper machine, and paper is made from above Only 470 g of the dispersion liquid was flowed to the paper machine, and paper was made using a suction (decompression device). The obtained wet paper was further covered with the same filter cloth and dehydrated with a hydraulic press device, and the cellulose concentration was adjusted to 13 to 14% by weight. The obtained wet paper was immersed in 1 liter of an aqueous solution of 3% by weight boric acid + 78% by weight ethyl cellosolve without peeling off the filter cloth, and was subjected to substitution treatment for about 30 minutes while occasionally rinsing the whole. With the both sides of the wet paper sandwiched between filter cloths made of PET, it is affixed on a drum dryer whose surface temperature is set to 100 ° C. and dried for a drying time of 180 seconds. The nonwoven fabric (a) sample CC-1 of this invention was obtained. CC-1 had a porosity of 81% and a film thickness of 63 μm. Evaluation of the solid content increment of the wet paper before and after solvent replacement confirmed that boric acid was present in CC-1 at 16 wt%. From the SEM image, it was confirmed that CC-1 is mainly composed of fibers with a thin fiber diameter of several tens to 100 nm, but some fibers of several hundred nm are also mixed, but the largest one is about 300 nm. It was a diameter. Further, according to the measurement of the transmittance distribution under the toluene immersion liquid described above, the value of Tr, av was 0.92, and the value of the film quality uniformity parameter H was 0.0035.

[Production Example 2]
Using the aqueous dispersion M1 prepared in Production Example 1, a cellulose / water dispersion having a cellulose concentration of 0.20% by weight was obtained in exactly the same manner as described above. The amount of the dispersion was adjusted to 470 g, 15 g of boric acid was further added, and the mixture was stirred for 5 minutes with a home mixer, and then paper was made by the same method as in Production Example 1, and both sides were sandwiched with filter cloth in the same manner as in Production Example 1. A wet paper having a solid content of about 10% by weight was obtained by performing a press treatment while being sandwiched between filter papers. In a state where both sides of the wet paper were sandwiched between filter cloths, the wet paper was pasted on a drum dryer whose surface temperature was set to 100 ° C. and dried in a drying time of 180 seconds. After drying, the filter cloth on both sides of the cellulose nonwoven fabric was peeled off to obtain a translucent white cellulose nonwoven fabric (a) (hereinafter referred to as CC-2) having a film thickness of 28 μm and a porosity of 50%. Evaluation of the solid content increment of the wet paper before and after solvent replacement confirmed that 21 wt% boric acid was present in CC-2. In the SEM image, it was confirmed that most of the fibers were thin fibers with a diameter of several tens to 100 nm and some fibers with a few hundreds of nm were mixed, but even the largest one had a fiber diameter of about 300 nm. Furthermore, the value of Tr, av was 0.91 and the value of the film quality uniformity parameter H was 0.0039 by the measurement of the transmittance distribution under the toluene immersion liquid described above.

[Production Example 3]
Dispersion M1 obtained in Production Example 1 was diluted with water to a cellulose concentration of 0.40% by weight, and a dispersion obtained by performing continuous dispersion treatment equivalent to 15 times with the above-described disk refiner was used as a papermaking dispersion. Used as. The dispersion average diameter Rv of this papermaking dispersion was measured and found to be 14.8 μm.
Next, using a 0.65 m wide inclined wire type continuous paper making machine (manufactured by Saito Iron Works Co., Ltd.) set at an inclination angle of 5 °, a polyolefin wire used as standard in the apparatus (this example) PET / nylon plain woven fabric used in Production Example 1 on the filtration rate of cellulose when using the papermaking dispersion used in (64%) (winding roll having a width of 0.76 m and a length of 100 m) As a filter cloth, the paper dispersion obtained above is continuously supplied at a supply speed of 13.0 L / min, the paper running speed is 4 m / min, and the degree of vacuum is 8 Continuous papermaking was performed by operating wet suction (inclined part) at a setting of .90 kPa and dry suction at a setting of 46.7 kPa at a reduced pressure. Immediately after paper making, the upper surface of the wet paper was covered with a filter cloth from the filter cloth roll, and then dehydrated by a press roll in a three-layer state of filter cloth / wet paper / filter cloth, and wound around the roll in a three-layer state. . The cellulose concentration of the wet paper obtained through these steps was about 14% by weight. Next, continuous replacement and drying treatment of Roll to Roll was performed as follows. A three-layer film is unwound from the three-layer film roll, and a substitution tank (solvent amount: 16 L, running) filled with a substitution solvent of an aqueous solution of 3% boric acid + 78% ethyl cellosolve at a running speed of 30 cm / min in all steps. Length: equivalent to 2m, the solvent is continuously prepared in consideration of mass balance, and the solution is continuously dried by a drum dryer whose surface temperature is set to 100 ° C after coming out of the bath. It wound up on the roll with the state of a 3 layer film | membrane. The three-layer membrane drying roll thus obtained was applied to a rewinder device to obtain a long (continuous nonwoven fabric) sample CC-3 of the nonwoven fabric (a) of the present invention. Evaluation of the solid content increment of the wet paper before and after solvent replacement confirmed that 17 wt% boric acid was present in CC-3. CC-3 had a porosity of 79% and a film thickness of 60 μm. In the SEM image, it was confirmed that most of the fibers were thin fibers with a diameter of several tens to 100 nm and some fibers with a few hundreds of nm were mixed, but even the largest one had a fiber diameter of about 300 nm. Furthermore, the value of Tr, av was 0.93 and the value of the film quality uniformity parameter H was 0.0026 by measurement of the transmittance distribution under the toluene immersion liquid described above.

[Production Example 4]
Instead of the aqueous dispersion M1, a dice piece of Nata de Coco (manufactured by Fujicco Co., Ltd., solid content: about 0.5% by weight), which is a water-containing BC gel used as a foodstuff, is thoroughly washed (water flow A BC / water dispersion having a solid content of 12% by weight was prepared by squeezing what was completely replaced with water below. Water was added to the dispersion, diluted with water so that the cellulose concentration became 1.0% by weight, pre-dispersed with a home mixer for 10 minutes, and then a high-pressure homogenizer (NS3015H manufactured by Niro Soavi (Italy)) The dispersion process was performed 4 times under an operating pressure of 80 MPa. Next, this dispersion liquid having a cellulose concentration of 1.0% by weight is further diluted with water so that the cellulose concentration becomes 0.20% by weight, and again subjected to a dispersion treatment with a home mixer for 5 minutes. Used as a papermaking dispersion. The dispersion average diameter Rv of this papermaking dispersion was measured and found to be 55 μm.

  Next, paper making was performed using the same filter cloth and batch type paper machine as in Production Example 1. Only 940 g of the papermaking dispersion was passed through the papermaking machine, and papermaking was performed using a suction (decompression unit). The obtained wet paper was further covered with the same filter cloth, dehydrated with a metal roller, and adjusted so that the cellulose concentration was 12 to 13% by weight. The obtained wet paper was immersed in 1 liter of an aqueous solution of 3% boric acid + 78% ethyl cellosolve without peeling off the filter cloth, and was subjected to a replacement treatment for about 30 minutes while occasionally rinsing the whole with a filter cloth. The sandwiched wet paper was placed on a metal plate, a weight was placed on it and dried at a constant length, set in a drying oven, and dried at 100 ° C. for 50 minutes. After drying, the nonwoven fabric was peeled off from the filter cloth to obtain a white cellulose nonwoven fabric (a) used in the present invention (film thickness: 70 μm, porosity: 80%, hereinafter BC-1). Evaluation of the solid content increment of the wet paper before and after solvent replacement confirmed that boric acid was present in BC-1 at 15 wt%. In the SEM image, only very thin fibers having a fiber diameter of 100 nm or less were confirmed. Furthermore, the value of Tr, av was 0.90 and the value of the film quality uniformity parameter H was 0.0038 by measuring the transmittance distribution under the toluene immersion liquid described above.

[Examples 1 to 4]
100 parts by weight of bisphenol A type epoxy resin (AER-250 manufactured by Asahi Kasei Epoxy Co., Ltd.), which is an epoxy compound of a thermosetting resin precursor, is melted at 120 ° C., and 18 parts by weight of a curing agent (m-xylylenediamine) Each of the cellulose nonwoven fabrics (a) obtained in Production Examples 1 to 4 was impregnated (impregnation time: within 5 minutes) with a temperature of 100 ° C. and a pressure of 9.81 MPa in a press machine. The composite of the present invention of the cellulose nonwoven fabric (a) and the cured epoxy resin (b) containing boric acid as the flame retardant (c) was obtained by thermosetting (curing time: 2 hours) under . The membrane properties of the resulting composite are summarized in Table 1. In any case, the film shows a high thermal decomposition start temperature and a low coefficient of thermal expansion as compared with a comparative example described later (a flame retardant (c) non-added system), and the composite of the present invention has excellent heat resistance. It was shown that. In addition, the refractive index of the cured epoxy resin was 1.60 by measuring the refractive index of the cured product of the single epoxy resin used in this example. Moreover, when the photoelastic modulus was measured especially about the composite_body | complex obtained by Example 1, the absolute value of the photoelastic coefficient was 7 * 10 < ^-12 > / Pa.

[Example 5]
100 parts by weight of bisphenol A type epoxy resin (AER-250 manufactured by Asahi Kasei Epoxy Co., Ltd.), which is an epoxy compound of a thermosetting resin precursor, is melted at 120 ° C., and 18 parts by weight of a curing agent (m-xylylenediamine) Two pieces of the cellulose non-woven fabric (a) CC-1 obtained in Production Example 1 were impregnated (impregnation time: within 30 minutes) and laminated in a press machine at a temperature of 100 ° C. and a pressure of 9 The composite of a cellulose nonwoven fabric (a) and a cured epoxy resin (b) was obtained by heat curing (curing time: 1 hour) under .81 MPa. The thickness was about 125 μm.

[Comparative Example 1]
A cellulose non-woven fabric (a) CR-1 was obtained by the same production method as in Example 1 except that the substitution solvent was an 80% by weight ethyl cellosolve aqueous solution with no boric acid added. The porosity of CR-1 was 80%, and the film thickness was 62 μm. From the SEM image, it was confirmed that CR-1 is mainly composed of fibers with a thin fiber diameter of several tens to 100 nm, but some fibers of several hundred nm are also mixed, but the largest one is about 300 nm. It was a diameter. Furthermore, the value of Tr, av was 0.92 and the value of the film quality uniformity parameter H was 0.0032 by the measurement of the transmittance distribution under the toluene immersion liquid described above. For CR-1, a composite with a cured epoxy resin was obtained under the same conditions as in Example 1. The obtained composite was used as Comparative Example 1.
-Evaluation method About the composite body produced in the said Example and the comparative example, various characteristics were measured with the following evaluation method. The evaluation results are shown in Table 1.
a) Resin content It calculated | required from the weight of the cellulose nonwoven fabric measured previously, and the weight of the obtained composite_body | complex.
b) Average linear expansion coefficient Change rate ΔL (%) of the sample length when the temperature was raised from T1 ° C. to T2 ° C. at a rate of 5 ° C. per minute using a TMA / SS120 type device manufactured by Seiko Instruments Inc. Was determined by the following equation. When the sample length at T1 ° C. was LT1, and the sample length at T2 ° C. was LT2, the load was 10 g and the measurement was performed in the tensile mode.
ΔL (T2) = (LT1-LT2) / LT1 / (T2-T1) × 10 ⁶ (ppm / ° C.)
Where T1 = 50 ° C., T2 = 150 ° C. or 250 ° C.

c) Total light transmittance It measured based on JIS K7361-1 using Nippon Denshoku Industries Co., Ltd. haze meter NDH2000.
d) Viscoelasticity Measurement Using RSAII manufactured by Rheometrics, the temperature was increased from room temperature to 300 ° C at a rate of 5 ° C per minute, and the storage elastic modulus E ′ and loss elastic modulus E ″ of the sample were measured.
The distance between chucks is about 20 to 30 mm, the sample width is about 2 to 4 mm, the measurement frequency is 1 Hz, the strain is 0.05%, the tensile modulus is measured, and the storage elastic modulus at 30 ° C. is E'30, 150 The storage elastic modulus at E 0 was set to E'150, and the storage elastic modulus at 250 ° C was set to E'250.

e) Thermal decomposition start temperature Using a thermogravimetric analyzer, measurement was performed in a nitrogen gas atmosphere. In order to make the inside of the resin completely dry, first heat treatment at 150 ° C. for 30 minutes, then cool to 30 ° C., raise the temperature at 10 ° C./min, and the base of the temperature region where weight loss does not occur The temperature at the intersection of the line and a straight line obtained by approximating the weight reduction curve after the start of weight reduction was defined as the thermal decomposition start temperature.
f) Refractive index of resin The refractive index of the resin in the D line (589 nm) was determined using a multi-wavelength Abbe refractometer DR-M2 manufactured by Atago Co., Ltd.
g) In-plane retardation (Re) measurement with light having a wavelength of 550 nm At 23 ° C., using a birefringence measurement apparatus RETS-100 manufactured by Otsuka Electronics Co., Ltd., the measurement light and the measurement surface are arranged perpendicularly, In-plane retardation (Re) at 550 nm was measured by a rotating analyzer method.

h) Measurement of photoelastic coefficient
A birefringence measuring apparatus described in detail in Macromolecules 2004, 37, 1062-1066 was used. A film tensioning device was placed in the laser beam path, and birefringence was measured while applying a tensile stress at 23 ° C. The strain rate during stretching was 20% / min (chuck interval: 30 mm, chuck moving speed: 6 mm / min), and the test piece width was 7 mm. From the relationship between birefringence (Δn) and tensile stress (σR), the photoelastic coefficient (CR) is calculated by finding the slope of the straight line in the linear region by least square approximation, and the absolute value (| CR |) of the photoelastic coefficient is obtained. It was. The smaller the absolute value of the slope is, the closer the photoelastic coefficient is to 0, indicating a preferable optical characteristic.
| CR | = | Δn | / σR
The absolute value of birefringence (Δn) was determined as follows.
| Δn | = | n1-n2 |
(CR: photoelastic coefficient, σR: stretching stress, Δn: birefringence, n1: refractive index in the stretching direction, n2: refractive index perpendicular to the stretching direction)
i) Haze Based on JIS K-7105, the haze (%) of the composite was measured using a turbidimeter (Nippon Denshoku Industries Co., Ltd., NDH2000).

  The composite of the present invention is applied to a plastic substrate for liquid crystal display elements, a substrate for color filters, a plastic substrate for organic EL display elements, a solar cell substrate, a touch panel substrate, a plasma display protection plate, a liquid crystal display protection plate, and a plasma display electromagnetic wave shielding substrate. It can be used suitably.

When drying wet paper obtained by papermaking from an aqueous dispersion of fine cellulose fiber obtained by processing an ultra-high pressure homogenizer from an Ecuadorian abaca pulp (operating pressure; 100 MPa, number of passes through a homovalve; 20 passes) The surface of the nonwoven fabric obtained by subjecting the ethyl cellosolve / water = 80/20 (g / g) mixed solution containing 3% by weight of boric acid to a substitution treatment and then drying at 100 ° C. with a drum dryer is scanned. It is an example of an image when it observes by 10000 time using an electron microscope (SEM). It is explanatory drawing which shows the measuring method of transmittance | permeability Tr and av of a 850 nm laser beam under the toluene impregnation of the nonwoven fabric containing a cellulose. It is a chart figure of the transmittance | permeability Tr obtained by making a laser beam of 850 nm scan in the length direction of a test tube using the method of FIG. The horizontal axis is the distance from the lowest measurement in the test tube length direction, and the vertical axis is the transmittance of the laser beam of 850 nm.

Claims (45)

  It comprises a nonwoven fabric (a) containing cellulose, a resin (b) other than cellulose, and a flame retardant (c), wherein (a) component is 0.1 wt% or more and 99 wt% or less, (b) component 1 to 99.8% by weight, and the component (c) is 0.01% to 50% by weight.   The composite according to claim 1, wherein pores of the nonwoven fabric (a) containing cellulose are filled with a resin (b) other than cellulose.   3. The composite according to claim 1, wherein a nonwoven fabric having a porosity of 35% or more and 95% or less is used as the cellulose-containing nonwoven fabric (a).   The composite according to claim 3, wherein a nonwoven fabric having a porosity of 50% or more and 95% or less is used as the nonwoven fabric (a) containing cellulose.   The composite according to claim 4, wherein a nonwoven fabric having a porosity of 70% or more and 95% or less is used as the nonwoven fabric (a) containing cellulose. As the nonwoven fabric (a) containing cellulose, the average transmittances Tr and av defined by the following formula (1) obtained by vertically scanning 850 nm light with respect to the nonwoven fabric in a state of being immersed in toluene are 0. The composite according to any one of claims 1 to 5, wherein a nonwoven fabric of 70 or more is used.
However, Tr and av are filled with toluene in a state in which the nonwoven fabric is adhered to the inner surface of the test tube, irradiates the test tube with light of 850 nm from a direction perpendicular to the nonwoven fabric, and linearly extends along the surface of the nonwoven fabric. Obtained by performing the same measurement in a state where only toluene is injected except for the nonwoven fabric, and the average value Tr, 1 of the transmittance obtained when scanning for a total length of 30000 μm (data points: 750) every 40 μm. It is defined by the following equation depending on the ratio of the average values Tr and 2 of transmittance.
Tr, av = Tr, 1 / Tr, 2 (1) The composite according to claim 6, wherein the nonwoven fabric (a) containing cellulose is a nonwoven fabric having a film quality uniformity parameter H defined by the following formula (2) of 0.018 or less.
However, H is filled with toluene in a state where the nonwoven fabric is adhered to the inner surface of the test tube, irradiated with light of 850 nm from the direction perpendicular to the nonwoven fabric, and 40 μm in a linear direction along the surface of the nonwoven fabric. Permeability obtained by performing the same measurement in the state in which only toluene is injected except for the standard deviation Tr, sd1 and the non-woven fabric of the transmittance obtained when scanning for a total length of 30000 μm (data score: 750) for each The following equation is defined by Tr and av obtained by Equation (1) in the same measurement as Tr and sd defined by the difference between the standard deviations Tr and sd2.
H = Tr, sd / Tr, av (2)
Here, Tr, sd = Tr, sd1-Tr, sd2.   As the nonwoven fabric (a) containing cellulose, a nonwoven fabric obtained by entanglement of cellulose fibers having a maximum fiber thickness of 2 to 1500 nm obtained by forming a film from a dispersion containing cellulose fibers by a papermaking method or a coating method is used. The composite according to any one of claims 1 to 7, wherein A non-woven fabric obtained by a papermaking method as a non-woven fabric containing cellulose (a), and as a dispersion for papermaking, the dispersion average diameter of cellulose fibers is 1 μm or more and 300 μm or less, and the cellulose fiber concentration is 0.01 wt% or more Using a dispersion of 1.0% by weight or less, as a filter cloth, it has the ability to filter out 95% or more of cellulose fibers in a papermaking dispersion by filtration at 25 ° C. under atmospheric pressure, and 25 under atmospheric pressure. By using a filter cloth having a water permeation amount of 0.005 cc / cm ² · s or more at 0 ° C., the filter cloth is placed on the wire of the papermaking apparatus, and the papermaking dispersion liquid is filtered on the filter cloth, whereby cellulose Produced by depositing fibers on a filter cloth to produce a wet nonwoven fabric with a solid content of 4% by weight or more of fine cellulose fibers, and peeling the nonwoven fabric from the filter cloth before or after the drying step. A composite according to any one of claims 1-8, characterized by using a woven fabric.   The nonwoven fabric (a) containing cellulose is a nonwoven fabric produced by a production method including a step of replacing a dispersion medium in a papermaking dispersion with an organic solvent before the drying step. The complex described.   The composite according to any one of claims 1 to 10, wherein an average linear expansion coefficient at 50 to 150 ° C is from 0.1 ppm / ° C to 25 ppm / ° C.   The composite according to any one of claims 1 to 11, wherein an average linear expansion coefficient at 50 to 250 ° C is from 0.1 ppm / ° C to 30 ppm / ° C. The composite according to any one of claims 1 to 12, wherein a relationship of storage elastic modulus in dynamic viscoelasticity measurement satisfies the following formula.
1≤E'30 / E'150≤100
(E′30 indicates the storage elastic modulus of the composite at 30 ° C., and E′150 indicates the storage elastic modulus of the composite at 150 ° C.)   The composite according to any one of claims 1 to 13, wherein the storage elastic modulus E'150 at 150 ° C of the composite in dynamic viscoelasticity measurement is 100 to 30000 MPa. The composite according to any one of claims 1 to 14, wherein a relationship of storage elastic modulus in dynamic viscoelasticity measurement satisfies the following formula.
1 ≦ E'30 / E'250 ≦ 100
(E′30 indicates the storage elastic modulus of the composite at 30 ° C., and E′250 indicates the storage elastic modulus of the composite at 250 ° C.)   The composite according to any one of claims 1 to 15, wherein the storage elastic modulus E'250 at 250 ° C of the composite in dynamic viscoelasticity measurement is 100 to 30000 MPa.   The total light transmittance is 60% or more, The composite_body | complex of any one of Claims 1-16 characterized by the above-mentioned.   The composite according to any one of claims 1 to 17, wherein a haze value is 80% or less.   The composite according to any one of claims 1 to 18, wherein an in-plane retardation (Re) at a wavelength of 550 nm is 50 nm or less at a thickness of 100 µm. The absolute value of a photoelastic coefficient is 80 * 10 < ^-12 > / Pa or less, The composite_body | complex of any one of Claims 1-19 characterized by the above-mentioned.   The composite according to any one of claims 1 to 20, wherein the nonwoven fabric (a) containing cellulose is a nonwoven fabric having a thickness in the range of 5 µm to 500 µm.   The composite according to any one of claims 1 to 21, wherein a nonwoven fabric produced using bacterial cellulose is used as the nonwoven fabric (a) containing cellulose.   The nonwoven fabric (a) containing cellulose is a nonwoven fabric produced by using cellulose obtained by refining wood-based cellulose, non-wood-based natural cellulose, or regenerated cellulose. The complex of any one of -21.   The composite according to any one of claims 1 to 23, wherein a nonwoven fabric produced using cellulose whose surface is chemically modified is used as the nonwoven fabric (a) containing cellulose.   A nonwoven fabric containing at least one selected from boric acid and a boric acid compound as the flame retardant (c), wherein the flame retardant is immobilized on the surface of cellulose, and the cellulose surface is chemically treated by the flame retardant The composite according to any one of claims 1 to 23, wherein at least one selected from modified nonwoven fabrics is used.   26. The composite according to any one of claims 1 to 25, wherein the nonwoven fabric (a) containing cellulose is a continuous nonwoven fabric prepared by a continuous process.   27. The composite according to any one of claims 1 to 26, wherein the nonwoven fabric (a) containing cellulose, which is a continuous nonwoven fabric prepared in a continuous process, is further continuously composited.   28. The composite according to any one of claims 1 to 27, wherein the refractive index of the resin (b) other than cellulose is more than 1.48 and less than 1.62.   29. The composite according to any one of claims 1 to 28, wherein the resin (b) other than cellulose comprises a styrene resin.   30. The composite according to claim 29, wherein the resin (b) other than cellulose is a styrene resin obtained by copolymerizing an acrylic resin monomer and a styrene resin monomer.   29. The composite according to any one of claims 1 to 28, wherein the resin (b) other than cellulose is a resin obtained by blending an acrylic resin and a styrene resin.   29. The composite according to any one of claims 1 to 28, wherein the resin (b) other than cellulose is an aromatic polycarbonate resin.   29. The composite according to any one of claims 1 to 28, wherein the resin (b) other than cellulose comprises a cyclic olefin-based resin.   29. The composite according to any one of claims 1 to 28, wherein the resin (b) other than cellulose comprises an epoxy resin.   The composite according to any one of claims 1 to 34, wherein the flame retardant (c) is a hydrate flame retardant.   The composite according to any one of claims 1 to 34, wherein the flame retardant (c) is a low-melting glass flame retardant. For the nonwoven fabric (a) containing cellulose,
(1) A method in which a monomer is impregnated and polymerized.
(2) A method in which a thermosetting resin precursor or a photocurable resin precursor is impregnated and cured.
(3) A method of drying after impregnating a solution of a resin other than cellulose.
(4) A method of impregnating a thermoplastic resin melt and cooling after defoaming.
37. The method for producing a composite according to any one of claims 1 to 36, wherein the resin (b) other than cellulose is filled and compounded by any one of the methods.   A plastic substrate for display comprising the composite according to any one of claims 1 to 36.   A plastic substrate for a display front plate, comprising the composite according to any one of claims 1 to 36 and having a thickness of 5 to 500 µm.   A display using the plastic substrate according to claim 38 or 39.   41. The display of claim 40, wherein the display is a liquid crystal display.   41. The display of claim 40, wherein the display is an organic electroluminescence (organic EL) display.   41. The display of claim 40, wherein the display is a plasma display.   41. The display of claim 40, wherein the display is a field emission display.   41. The display of claim 40, wherein the display is a surface electric field display.

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