CN100510790C - Light diffusion film - Google Patents

Abstract

Disclosed is a light diffusion film comprising a light diffusion layer which has adequate light transmitting properties and light diffusion properties while exhibiting high abrasion resistance. In this light diffusion film, resin particles are hardly separated from the light diffusion layer. Specifically disclosed is a light diffusion film wherein a light diffusion layer, which is obtained by dispersing acrylic urethane resin particles in a resin binder, is arranged on at least one side of a transparent sheet-like base. Preferably, the resin binder is an acrylic copolymer containing 1-50% by mass of an acrylic monomer unit having a hydroxyl group and crosslinked by a polyisocyanate, and the resin particles contain a curing catalyst which serves as a catalyst for a crosslinking reaction between an acrylic polyol and a polyisocyanate.

Description

Optical diffusion film

Technical field

The present invention relates to have the film of light diffusing, particularly as the structure member of the backlight module of liquid crystal indicator and the optical diffusion film that uses.

Background technology

Optical diffusion film is used to spread the light of pointolite or linear light source, perhaps adjusts the angle of emergent light, so that obtain homogeneous and the high face illumination of front face brightness.This optical diffusion film is widely used in the LCD that for example is equipped in mobile phone, digital camera etc. and liquid crystal TV set etc.

All the time, be equipped in computer, mobile phone, digital camera etc. liquid crystal indicator general structure as shown in Figure 1.Optical diffusion film 7 uses as one of composed component of backlight module 2 usually.Optical diffusion film 7 generally is configured between light guide plate 5 and the prismatic lens 8, and its effect is that the emergent light in the light guide plate 5 is produced the drift angle in prismatic lens 8 sides, and reuses the light that reflects once again from prismatic lens 8.

In addition, the cross section structure of general optical diffusion film as shown in Figure 2.Generally speaking, optical diffusion film 7 is provided with transparent sheet-like base material 10, light diffusion layer 11 and back layer 12, and light diffusion layer 11 is formed at the one side of base material 10, and the back layer 12 of the another side of base material 10 is used to prevent to bond.Contain photodiffusion material 13 and resinoid bond 14 in the light diffusion layer 11.

In the optical diffusion film in the past, form the light diffusion layer that constitutes by synthetic resin layer, sneaked into pearl in this synthetic resin as the transparent resin system of photodiffusion material on the surface of transparent base; Known resinous pearl comprises the pearl (for example, with reference to patent documentation 1) of transparent acryl resin system, the proper sphere shape particle of polystyrene system (for example, with reference to patent documentation 2) etc.In addition, employed synthetic resin layer is (for example with reference to the patent documentation 3) that is made of the 2 package curing type cementing agents that the polyvalent alcohol and the isocyanates of acrylic polyol, polyester polyol etc. are adjusted.In the optical diffusion film of being put down in writing, above-mentioned resin system pearl is by the pearl that only is not embedded in the synthetic resin layer, when the pearl that also has part to protrude in synthetic resin layer constitutes, thereby preferably (for example, with reference to patent documentation 1), for example as the backlight module of liquid crystal indicator the time, by adopting the optical diffusion film of this structure, good diffusion effect and the light harvesting effect of light can be given, bright, consistent liquid crystal display face can be formed by the back light generation.

But, in the existing optical diffusion film, to improving mar resistance and preventing the research that resin particle comes off, abundant not as what the research of optical characteristics was done, to the mar resistance of optical diffusion film with prevent that the processing that resin particle comes off neither be very abundant, in process, can cause damage to the surface of film.In the process of shearing according to the shape of backlight module design, the diffusingsurface generation damage of light and the problem that resin particle comes off take place easily particularly.And this resin particle that comes off from synthetic resin layer, also often be the reason that the optical diffusion film surface produces new wound and defective.

When the optical diffusion film of the resin particle that will contain damage or come off is installed on the backlight module, on liquid crystal display picture, will produce defective, reduce quality, therefore, in the technology of processing optical diffusion film, to the processed goods of the perforation that damage takes place or come off, by visual examination with its eliminating and do useless.Therefore, the anti-deciduous of mar resistance and resin particle is insufficient, is to cause that the optical diffusion film yield reduces and the low reason of productivity.

In order to prevent this damage and defective, the hardness of raising resin particle and synthetic resin laminar surface is very important, but correspondingly, just becomes difficult to comprising that the minimizing resin particle comes off and reduces the raising that produces the whole flexibility (adaptability) of operation of damaging by coming off.

Particularly above-mentioned from synthetic resin layer the outstanding pearl of part because little and more be easy to generate and come off with the contact area of the synthetic resin layer that keeps it.According to the needed optical characteristics of light diffusing sheet, often be designed to be increased to about long-pending half of all surfaces the protuberate of pearl is long-pending, in the manufacturing process of optical diffusion film, resin particle comes off easily from synthetic resin layer, and this problem is the low major reason of pollution, damage and production efficiency that causes optical diffusion film.

Patent documentation 1: open flat 5-073602 communique in fact

Patent documentation 2: No. 3010871, practical new case login

Patent documentation 3: the spy opens the 2002-357703 communique

Summary of the invention

The purpose of this invention is to provide a kind of optical diffusion film, this film has sufficient light transmission and light diffusing, the mar resistance height, and contain the difficult light diffusion layer that comes off from light diffusion layer of resin particle, also have good flexibility (adaptability) of operation.

After the inventor in order to achieve the above object and studies with deepening continuously, find to form the difficult optical diffusion film that comes off from light diffusion layer of resin particle by using specific resinoid bond and resin particle can improve the rub resistance of light diffusion layer face.

That is to say, the invention provides a kind of optical diffusion film, on at least one face of its transparent sheet-like base material, be provided with resin particle and be scattered in light diffusion layer in the resinoid bond, it is characterized by: above-mentioned resinoid bond is the multipolymer after acrylic polyol or polyester polyol use polyisocyanate crosslinked, and the resin particle in the above-mentioned resinoid bond is the acrylated polyurethane resin particle that contains hardening catalyst, and this hardening catalyst is the catalyzer that the catalysis polyisocyanate carries out cross-linking reaction.

Optical diffusion film among the present invention has good mar resistance, and resin particle is difficult for coming off from light diffusion layer, and its reason is not clear and definite fully as yet.Because the synthetic resin layer of resin particle and formation light diffusion layer all is to be made of the multipolymer by polyisocyanate and polyol resin adjustment, so, himself be difficult to be damaged.More because resin particle contains the hardening catalyst of polyol resin and polyisocyanate, so the surface energy at resin particle and synthetic resin carries out sclerous reaction very fast, keep resin particle because at first can think around resin particle, to form the synthetic resin layer that does not have distortion.

Optical diffusion film among the present invention, can provide a kind of resin particle to be difficult for the light diffusion layer that from resinoid bond, comes off, because in the present invention, use contains the acrylated polyurethane resin particle of hardening catalyst as photodiffusion material, this hardening catalyst is the catalyzer that the above-mentioned polyisocyanate of catalysis carries out cross-linking reaction in the resinoid bond of light diffusion layer, use acrylic polyol or polyester polyol by polyisocyanate the multipolymer after crosslinked as resinoid bond, so the cross-linking reaction of the resinoid bond on the interface of resin particle and resinoid bond preferentially and is fast carried out.And, acrylated polyurethane resin particle self is compared with existing acryl resin, styrene resin particle etc. has good mar resistance, in addition, use be easy to obtain hardness of film by the polyisocyanate crosslinked copolymers as resinoid bond, so the light diffusion layer face is difficult for sustaining damage.On the other hand, the amount of hardening catalyst need not be added the degree that hinders optical characteristics to, so can keep light transmission and the light diffusing same with existing optical diffusion film.

Description of drawings

Fig. 1 is the general structural drawing of liquid crystal indicator.

Fig. 2 represents the sectional view of an embodiment of optical diffusion film among the present invention.

Symbol description

1. liquid crystal cells

2. backlight module

3. light source

4. reflectance coating

5. light guide plate

6. reflector plate

7. optical diffusion film

8. prismatic lens

9. diaphragm

10. transparent sheet-like base material

11. light diffusion layer

12. back layer

13. photodiffusion material

14. resinoid bond

Embodiment

At first, optical diffusion film structure of the present invention is described.Optical diffusion film of the present invention at least by transparent flat substrates and on the one side at least of base material the light diffusion layer that forms constitute.In addition, as required,, can also design and contain the function that prevents to bond, prevent charged function, prevent to damage the back layer of function, second one of them above function such as light diffusion layer function at the another side of base material.

Transparent sheet-like base material of the present invention does not limit certain material especially, but considers from the flatness and the physical strength on surface, preferably uses polyethylene terephthalate (PET) film.Preferred 10～300 μ m of the thickness of base material.When thinner than 10 μ m, not only use difficulty, also can take place because of curling that thermal shrinkage produces, and make operation significantly low, processability reduces.When thicker than 300 μ m, the visible light transmissivity of base material itself is low, the easy step-down of the front face brightness of backlight module.On the surface of transparent flat substrates, the adaptation for the back layer that improves substrate surface and light diffusion layer or form as required can be provided with the processing layer that is easy to bond.Be easy to the processing of combination, can exemplify out, perhaps implement modes such as crown processing at substrate surface as smearing the resin of the adaptation that improves both.

The light diffusion layer of the optical diffusion film among the present invention contains photodiffusion material and resinoid bond at least.The resin particle that is used as photodiffusion material among the present invention is an acroleic acid polyurethane resin particle.

The acrylated polyurethane resin particle, because have highdensity cross-linked structure, thus very strong thermotolerance and solvent resistance are arranged, and, also have the distinctive high transparent of acryl resin.The inventor finds when using the acrylated polyurethane resin particulate as photodiffusion material, can keep as necessary mist degree of optical diffusion film and transmitance, and compare with resin particles such as the existing polymethylene methacrylate (PMMA) that is commonly used as photodiffusion material, polystyrene, silicones, it has the residual abrasive characteristics on light diffusion layer that are difficult for.

To this, inventors think owing to following reason: the acrylated polyurethane resin particulate has highdensity cross-linked structure, simultaneously, compare, have the advantages that to be easy to the plastic degeneration with resin particles such as the polymethylmethacrylate that was commonly used, polystyrene, silicones in the past.Promptly; can think that the light diffusion layer of acrylated polyurethane resin microparticulate in resinoid bond has following characteristics: on the one hand; it is inner easily deformable because of the plasticity of acrylated polyurethane resin particulate; on the other hand; because be that acryl resin is to carry out the structure of three-dimensional cross-linked animi resin cementing agent as protection by polyisocyanate, so its surface is difficult for the breakage because being subjected to external stress.

The acrylated polyurethane resin particulate that uses is if contain the resin particle of hydroxyl on the surface, so in the cross-linking reaction of resinoid bond, excessive polyisocyanate generation cross-linking reaction in the hydroxyl on resin particle surface and the resinoid bond, thereby the effect of the resinoid bond around the promotion photodiffusion material, simultaneously, because between photodiffusion material and resinoid bond, can form cross-linked structure, so can further improve the cross-linking density of light diffusion layer.These acrylated polyurethane resin particulates can be made by disclosed manufacture process, these open processes of making comprise polymerization processes such as outstanding turbid polymerization, emulsion polymerization, and will be dissolved in resin in organic solvent emulsification etc. in aqueous medium.And, add hardening catalyst in advance in the raw material before these manufacturing process in right amount, can obtain existing on the resin particle surface at least the material of hardening catalyst.

These are not contained the surface of the acrylated polyurethane resin particle of hardening catalyst, can carry out surface treatment with the solvent that contains above-mentioned hardening catalyst, but, for the coating that forms light diffusion layer not being worried to produce stable smearing under the situation of gelation, the preferred hardening catalyst that remains in the resin particle surface that adds in the fabrication phase of resin particle that uses.

Hardening catalyst in the catalysis polyisocyanate cross-linking reaction that is used for resinoid bond of the present invention, because be the material of promotion, so need not to be the relevant material of polyreaction, cross-linking reaction in the time of to form with resin particle in the cross-linking reaction at the interface of resinoid bond and resin particle.But, because these hardening catalysts are the materials that also can bring into play catalytic effect when resin particle forms, so the preferred catalyzer that adds can be brought into play function as catalyzer effectively to resin particle and synthetic resin layer both sides.

Manufacture method as the acrylated polyurethane resin particle that uses hardening catalyst, can be for example in the presence of hardening catalyst, make the monomer and diisocyanate or the polyisocyanate polyisocyanate polyaddition that contain hydroxyl, after making prepolymer with urethane bond, with acrylic component and the jointly outstanding turbid polymerization of polymerization initiator, be formed in the resin particle that contains hardening catalyst in the resin particle, can produce the sclerosis catalytic action on the resin particle surface.

Above-mentioned monomer with hydroxyl, can exemplify out as glycolss such as polyester-diol, PTMEG, polyester amido glycol, PCDL, polyalcohols such as the lactone polyester polyol that obtains by the ring-opening polymerization of cyclic ester monomer, polyether glycol, polyester ether polylol, polycarbonate polyol, or in molecule, contain poly-alkylene ethylene glycol (methyl) esters of acrylic acid of vinyl.

As diisocyanates, can exemplify out as HDI, isophorone diisocyanate etc.As the polyisocyanate class, can exemplify out as being the isocyanuric acid ester type of basic trimerizing or based on the biuret type of HDI based on the adduct type of the interpolation polyvalent alcohol of the aliphatic isocyanates class of HDI (HDI) class that is difficult for xanthochromia, XDI (Xylene Diisocyanate) class, with HDI.In the kind of hardening catalyst, can adopt general triethylenediamine as the carbamate hardening catalyst, N methyl piperazine, N, N '-diformazan benzylamine, N, N '-dimethyl dodecyl amine, N, N, N ', N '-tetramethylethylenediamine, N, N, N ', N '-tetramethyl-1, the 6-hexamethylene diamine, N, N, N ', N '-tetramethyl 1, amines such as 3-two amido butane, tributyltin chloride, tetrabutyltin, dibutyl tin laurate, two lauric acid tin octylates, potassium oleate, metatitanic acid 2-ethyl hexane, metallic compounds such as zinc naphthenate, sulfone acid, phosphate, acid such as carboxylic acid.Particularly dibutyl tin laurate, two lauric acid tin octylates have good catalytic effect to aliphatic isocyanates and are fit to.Preferred 0.0001～0.5 quality % of the hardening catalyst amount that contains in the resin particle, more preferably 0.001～0.1 quality %.

Particularly, when use contained the hardening catalyst of tin, the tin content of the hardening catalyst cause in the preferred resin particle was 1～300ppm, and this content is measured with ICP Emission Spectrophotometer method or fluorescent x-ary analysis.

As the prepolymer that contains above-mentioned urethane bond with by the acrylic component of free radical polymerization, can exemplify (methyl) acrylic acid carboxylate, carbonitrile derivatives and with the organic acid vinyl ester of (methyl) acrylic ester copolymerization, unsaturated acid ester, benzenesulfonamide derivative system monomer etc.As polymerization initiator; preferably when polymerization, produce the material of group; for example can exemplify out benzoyl group superoxide, the peroxidating trimethylace tonitric tert-butyl ester, t-butylperoxide-organic peroxides such as 2 ethyl hexanoic acid ester; and the two azo-compounds such as (cyclohexanes-1-nitrile) of 2,2 azos.

In addition, the suspension stabilizing agent that uses in outstanding turbid polymerization can exemplify out water soluble resin as cellulose families such as methylcellulose, hydroxy ethyl cellulose, carboxy methyl celluloses, polyvinyl alcohol (PVA), polyglycol, polyvinylpyrrolidone, polyacrylate etc.The amount and the kind of the suspension stabilizing agent that uses can be according to the stability of outstanding turbid system and arbitrary decision, and generally speaking, along with increasing of suspension stabilizing agent dosage, having stability increases, the trend that the particle diameter that obtains diminishes.

The preferred proper sphere shape of the shape of acrylated polyurethane resin particle.The preferable range of this resin particle mean grain size is 1～30 μ m.Mean grain size is littler than 1, and the light of process light diffusion layer just sees through without diffusion, and the diffusion effect of light is reduced.Mean grain size is bigger than 30 μ m, because thick resin particle easily comes off and produces defective, also lacks homogeneity easily easily, and foreign body sensation is arranged on the appearance of film.

In addition, in the part photodiffusion material, also other resin particles, inorganic particulate or the inorganic-organic stuff and other stuff that do not contain hardening catalyst can be mixed use with the resin particle that contains hardening catalyst.At this moment, in the scope of each characteristic that does not hinder optical diffusion film, the addition than the addition that is scattered in the acrylated polyurethane resin particle that contains hardening catalyst in the resinoid bond lacks can prevent on the resin particle falling-off effect even more ideal in raising.

In addition, in order to fill up because of giving prominence to gap, the smooth light diffusion layer surface configuration between the oversize grain that is easy to form on the light diffusion layer surface and improving outward appearance, as the part of photodiffusion material, can contain mean grain size is the proper sphere shape resin particle of 1～5 μ m.

In the present invention, the resin glue that is used for the light diffusion layer of optical diffusion film is the multipolymer that acrylic polyol or polyester polyol form after polyisocyanate is crosslinked.

Among the present invention, so-called acrylic polyol is a kind of acrylic resin, and it obtains through the unsaturated monomer composition that polymerization contains hydroxyl, and, contain (methyl) acrylic acid unit as textural element.

Acrylic polyol preferably contains the multipolymer of the acrylic monomers unit with hydroxyl of 1～50 quality % with the multipolymer that the crosslinked back of polyisocyanate forms, and this acrylic monomers with hydroxyl is the inscape of the acrylic polyol in the multipolymer.

The unsaturated monomer that contains hydroxyl can be to contain the unsaturated monomer that the acrylic monomers with hydroxyl selected the unsaturated monomer of hydroxyl and allyl alcohol, styron, crotonyl alcohol etc. contain hydroxyl from hydroxy ethyl methacrylate, hydroxyethyl methyl acrylate, hydroxypropyl acrylate, hydroxypropyl methyl acrylate etc.Perhaps can exemplify out the unsaturated monomer that contains hydroxyl that obtains by divalent alcohol or reactions such as epoxy compound and unsaturated carboxylic acid, wherein, divalent alcohol can be ethylene glycol, propylene glycol, phenylglycidyl ether etc., and unsaturated carboxylic acid can be acrylic acid, maleic acid, fumaric acid etc.Can from the above-mentioned unsaturated monomer that contains hydroxyl, select monomer more than at least a to carry out polymerization and make acrylic polyol, thereby contain (methyl) acrylic acid unit.

In addition, can be from methyl methacrylate, the butylacrylic acid methyl esters, dodecyl methacrylate, methacrylate, the ethyl propylene acid esters, the butylacrylic acid ester, the isobutyl acrylate, the 2-ethylhexyl acrylate, acrylic acid, methacrylate, acrylamide, MAAm, N hydroxymethyl acrylamide, glycidyl acrylate, acrylic monomers and styrene such as glycidyl methyl acrylate, select the unsaturated monomer of the ethene more than a kind or 2 kinds in the vinyl cyanide etc., with itself and the above-mentioned polymerization of unsaturated monomers that contains hydroxyl, make acrylic polyol.

In the ratio of monomer component, the acrylic monomers composition that contains hydroxyl is 1～50% in multipolymer, and other monomer components are 5～80%.

The hydroxyl value of acrylic polyol is preferably 25～500.Less than 25 o'clock, because cross-linking density is low excessively, the hardness of light diffusion layer and solvent resistance were on the low side easily in hydroxyl value.In hydroxyl value greater than 500 o'clock because cross-linking density is too high, can be easy to generate become fragile, light diffusion layer breaks, produce situation such as defective, makes the operation reduction that adds man-hour.

Herein, so-called hydroxyl value is commonly referred to as, in typically referring to and the milligram number of the acetic acid that produces when acetylation 1g experiment material and needed potassium hydroxide.The experiment material acrylic polyol is as paint (solution) time, and hydroxyl value is the numerical value that is converted into the hydroxyl value that is equivalent to the solid-state experiment material of 1g.

In addition, as required, can from diethyl maleate, dibutyl maleate, two (2-ethylhexyl) maleate, dibutyl fumarate, two (2-ethylhexyl) fumarate, N-phenylmaleimide, select more than a kind or 2 kinds as the resin modifying agent, above-mentioned multipolymer and resin modifying agent are carried out copolymerization, and the component ratio of the resin modifying agent in the multipolymer is preferred below 50%.

The concrete in the present invention acrylic polyol that uses is " ア Network リ デ イ Star Network A-801-P ", " ア Network リ デ イ Star Network 56-719 ", " ア Network リ デ イ Star Network AU-1042 " ", " ア Network リ デ イ Star Network WDU-938 ", " ア Network リ デ イ Star Network A-817 ", " ア Network リ デ イ Star Network A-823 ", " ア Network リ デ イ Star Network A-829 " (big Japanese イ Application キ chemical industry society make) etc.

The resin that uses among the present invention is the resin that obtains with polyisocyanate cross-linked polyester polyvalent alcohol, as long as it is not just having the special restriction of using as having the transparency when filming.Usually, polyester polyol has good weatherability, mar resistance and processability etc., and by polyisocyanate crosslinked after, these characteristics can further improve.On the high basis of the transparency, a small amount of packing material that adds in cementing agent disperses easily.Therefore, the total light transmittance of optical diffusion film be can improve, and the xanthochromia that produces by ultraviolet ray, deterioration etc. reduced by using this resin.The rubber-like film coated surface of filming of the light diffusion layer that uses among the present invention can absorb the load that friction produces by the elastic deformation of filming, produces permanent abrasive function so have the film coated surface of alleviation, and has self-regeneration, thereby preferred.

The polyester polyol of Shi Yonging in the present invention, be with the pure and mild polybasic acids of multivalence, under the condition that the hydroxyl value of multivalence alcohol is Duoed than above-mentioned polyacid carboxyl number, react and make, multivalence alcohol can be ethylene glycol, diglycol, propylene glycol, dipropylene glycol, 1, the 3-butylene glycol, 1, the 4-butylene glycol, 1, the 5-pentanediol, neopentyl glycol, 1, the 6-hexanediol, decanediol, 2,2,4-trimethyl-1, the 3-pentanediol, trihydroxymethyl propane, hexanetriol, glycerine, pentaerythrite, cyclohexane diol, the hydrogenation bisphenol-A, two (methylol) cyclohexane, quinhydrones two (hydroxyethyl ether), three (hydroxyethyl) isocyanuric acid ester, xylylene ethylene glycol etc., polybasic acids can be maleic acids, fumaric acid, succinic acid, hexane diacid, decanedioic acid, azelaic acid, trihemellitic acid, terephthalic acids, phthalic acid, m-phthalic acid etc.

The mean molecular weight of the polyester polyol that obtains under the condition of the hydroxyl surplus of using is more than 500 below 300000, and is preferred more than 2000 below 100000.And this hydroxyl value is more than 5 below 300, and is preferred more than 10 below 200.

Hydroxyl number in the above-mentioned polyester polyol, just there is not special restriction so long as have in 1 molecule more than 2, still, if the hydroxyl value in the solid constituent is 10 when following, can reduce crosslinked counting, thereby reduce coating rerum naturas such as solvent resistance, water tolerance, thermotolerance, skin hardness.The polyester polyol that uses in crosslinked the present invention with polyisocyanate and in the resin that obtains, concrete operable polyester polyol have " バ-ノ Star Network D6-439 ", " バ-ノ Star Network D-115-80 ", " バ-ノ Star Network D7-885 ", " バ-ノ Star Network DS-1000 ", " バ-ノ Star Network D-161 " (big Japanese イ Application キ chemical industry society make) etc.

The resinoid bond that uses among the present invention can use respectively according to purposes, when for example requiring the hardness of film and the transparency, the preferred multipolymer that obtains by polyisocyanate cross-linked acrylic acid polyvalent alcohol that uses, when thinking further to improve the mar resistance on optical diffusion film surface, the preferred multipolymer that obtains by polyisocyanate cross-linked polyester polyvalent alcohol that uses.Use polyisocyanate among the present invention, being can be mutually crosslinked with the hydroxyl of acrylic polyol or polyester polyol, based on the material of aliphatic isocyanates such as HDI class, XDI class, and based on the material of aromatic isocyanates such as TDI class, MDI class, and based on the polyisocyanate of aliphatic isocyanates such as HDI (HDI) class, XDI (Xylene Diisocyanate) class because be difficult for producing the xanthochromia that causes by ultraviolet ray by preferred.These isocyanates are being made in the sex change type of polyisocyanate, can exemplified out, with the isocyanuric acid ester type of HDI trimerizing, perhaps based on the biuret type of HDI etc. as in aliphatic isocyanates such as HDI class, XDI class, adding the mould assembly that adds of multivalence alcohol.Wherein, preferred especially in HDI, add multivalence alcohol add the mould assembly polyisocyanate because in the processing technology of optical diffusion film, make optical diffusion film obtain very favorable mechanical properties easily.

The equivalent proportion preferable range of the hydroxyl in relative acrylic polyol of the isocyanates in the polyisocyanate or the polyester polyol is 0.7～3.0.Equivalent proportion is less than 0.7 o'clock, the easy step-down of cross-linking density, and the erasibility and the solvent resistance of light diffusion layer are insufficient, and are easy to generate coming off of resin particle.Equivalent proportion is greater than 3.0 o'clock, can carry out crosslinkedly between polyisocyanate molecules, and light diffusion layer becomes fragile easily.

Here, isocyanates is generally tried to achieve by following formula 1 equivalent proportion (NCO/OH) of hydroxyl.

$\frac{\mathrm{NCO}}{\mathrm{OH}}=\frac{\mathrm{Iw}\×\mathrm{In}\×561}{\mathrm{Aw}\×\mathrm{Ao}\×42}$

In this formula, the meaning representation separately of Iw, In, Aw, Ao is as follows,

Iw: polyisocyanate is converted into the mass fraction of solid constituent,

In: effective NCO content (%) in the solid constituent of polyisocyanate,

Aw: acrylic polyol or polyester polyol are converted into the mass fraction of solid constituent,

Ao: the hydroxyl value of the solid constituent in acrylic polyol or the polyester polyol.

In optical diffusion film of the present invention, resin particle cannot treat different things as the same with respect to the amount of being used of resinoid bond, because will change according to the mean grain size of employed resin particle and the thickness of light diffusion layer, but, 100 mass parts with respect to the resinoid bond solid constituent, the use amount of resin particle can be 5～400 mass parts, wherein preferred 10～250 mass parts.If when resin particle is discontented with 5 mass parts with respect to the resinoid bond of 100 mass parts, can be difficult to obtain good light diffusing energy.On the other hand,, can make light transmission low, be difficult to utilize sufficient light quantity if surpass 400 mass parts.

In the employed in the present invention resin particle, use contains the resin particle of hardening catalyst as photodiffusion material, the material that use acrylic polyol or polyester polyol obtain after polyisocyanate is crosslinked is as resinoid bond, so, interface at resin particle and resinoid bond, the cross-linking reaction of resinoid bond can preferentially and apace be carried out, and can provide resin particle to be difficult for the light diffusion layer that comes off from resinoid bond.

In the light diffusion layer of optical diffusion film of the present invention, in the scope of each characteristic that does not hinder optical diffusion film,, can also mix and use as spreading agent, plastifier, charged preventor, deterioration preventing agent etc. except above-mentioned material.

The thickness of light diffusion layer cannot treat different things as the same, because will change wherein preferred 5～50 μ m, more preferably 8～40 μ m according to the mean grain size of the resin particle that uses and the combined amount of resin particle.

Optical diffusion film among the present invention can not have back layer, but in most cases, in order to prevent to produce scratch with the face of the opposite side of light diffusion layer of optical diffusion film, and prevents to produce bonding etc. with light guide plate, and back layer can be set.

In the back layer of optical diffusion film in the present invention, contain resinoid bond at least.As required, can contain and be useful on the charged preventor that prevents the lubricant that bonds and be used for suppressing producing static to optical diffusion film, and ultraviolet light absorber, screening uv-ray agent, photodiffusion material etc.

The resinoid bond that in the back layer of optical diffusion film of the present invention, contains, if do not hinder the material of the optical diffusion film transparency just to be not particularly limited, but preferred thermoplastic methacrylic resin, thermoplasticity methacrylic acid-styrene copolymerized resin and vibrin or the resin of acryl resin after polyisocyanate is crosslinked.

When allowing back layer have function as second light diffusion layer, can use the light diffusion layer among the present invention.When the two sides of optical diffusion film is provided with light diffusion layer, can prevent from as bonding to obtain higher mist degree on the function basis of layer at it.

The thickness of the back layer that adopts is suitably 1～15 μ m, but when allowing back layer have function as second light diffusion layer, the thickness of the back layer of employing is suitably 5～50 μ m, and specially suitable thickness is 8～40 μ m.

In order to make the optical diffusion film among the present invention, to coat coating in the one side of transparent sheet-like base material at least as light diffusion layer, allow it form light diffusion layer.At its another side, can coat coating as required as back layer, allow it form back layer.

Can utilize the general worker's mode that is coated with as coating process.For example can utilize that scraper plate, cutter are scraped, cast, dipping, impregnating apparatus, screen pack, spin coating, oppositely roller coat (reverse roll), air knife, intaglio, spraying, curtain formula (curtain), extrude, spray water (fountain), kiss-coating (kiss), rod are coated with (rod), extruding (squeeze), are rotated in the forward device, touch roll coating methods such as (kiss roll).

The drying that can utilize general drying mode to film.For example can utilize hot blast, infrared ray, microwave, induce drying modes such as heating.After the drying, as required, use the temperature and time of setting to carry out heat aging and handle.

Optical diffusion film among the present invention is to make by as above method, and the optical diffusion film that it is particularly suitable as the backlight module that is configured for liquid crystal indicator uses, and is limited to this kind purposes but have more than, and goes in the purposes of all necessity of light diffusion light.

Embodiment

The present invention will be described by the following examples.

Synthesis example 1

In the reaction vessel that has stirrer, thermometer, refrigeratory and nitrogen conduit of drying, sneak into the polycaprolactone trihydroxy alcohol (プ ラ Network セ Le 308, ダ イ セ Le chemistry society makes) of 42 mass parts, the HDI of 50 mass parts (below, slightly be called HDI), the dibutyl tin laurate of 0.1 mass parts, in nitrogen environment, under 120 ℃ condition, reacted while stirring 10 hours.Then, under reduced pressure, remove unreacted HDI after, add toluene and obtain the prepolymer that nonvolatile component is 90 quality % (1).

In the separable flask that has stirrer, sneak into 2% methylcellulose water of 670 mass parts, stir on one side, add on one side by the prepolymer (1) of 102 mass parts, the methyl methacrylate of 100 mass parts, the toluene of 10 mass parts, the peroxidating trimethylace tonitric tert-butyl ester (the パ one Block チ Le PV of 2 mass parts, the manufacturing of Japan grease society) solution that constitutes is made suspension.Under stirring condition, suspension was warmed up to 60 ℃ of reactions after 5 hours, it is warmed up to 100 ℃ with the time more than 1 hour, uses the azeotropic method separation of methylbenzene, after the cooling, carry out Separation of Solid and Liquid, clean, dry, classification, and obtain acrylated polyurethane resin particle (I).The mean grain size of this particle is 16 μ m, and the content of hardening catalyst approximately is 0.05 quality %.

Synthesis example 2

Adopt and method that synthesis example 1 is same, the polycaprolactone glycol (プ ラ Network セ Le 210, ダ イ セ Le chemistry society make) of 48 mass parts, the HDI of 42 mass parts, two lauric acid tin octylates of 0.1 mass parts are reacted, add toluene, obtain the prepolymer that nonvolatile component is 70 quality % (2).

In the separable flask that has stirrer, sneak into 3% methylcellulose water of 700 mass parts, stir on one side, add on one side by the prepolymer (2) of 128 mass parts, the methyl methacrylate of 75 mass parts, the n-BMA of 25 mass parts, t-butyl peroxyization-2 ethyl hexanoic acid ester (カ ヤ エ ス テ Le O of 3 mass parts, the manufacturing of chemical drug ア Network ゾ society) solution that constitutes is made suspension.Under stirring condition, suspension was warmed up to 60 ℃ of reactions after 5 hours, it is warmed up to 100 ℃ with the time more than 1 hour, uses the azeotropic method separation of methylbenzene, after the cooling, carry out Separation of Solid and Liquid, clean, dry, classification, and obtain acrylated polyurethane resin particle (II).The mean grain size of this particle is 6 μ m, and the content of hardening catalyst approximately is 0.05 quality %.

Synthesis example 3

Adopt and method that synthesis example 1 is same, polycaprolactone glycol (プ ラ Network セ Le L212AL with 44 mass parts, ダ イ セ Le chemistry society makes), the HDI of 25 mass parts, after 0.15 two lauric acid tin octylates of mass parts react, add lactone sex change (methyl) acrylate (the プ ラ Network セ Le FM3 of 15 mass parts, ダ イ セ Le chemistry society makes), poly-alkylene ethylene glycol (methyl) acrylate of 81 mass parts (Block レ Application マ one E, Japan grease society makes) and the toluene of 18 mass parts, 80 ℃ of reactions down, obtain the prepolymer that nonvolatile component is 90 quality % (3).

The methylcellulose of sneaking into 1000 mass parts in the separable flask that has stirrer is 3% water, stir on one side, one side adds the solution by the toluene formation of the peroxidating trimethylace tonitric tert-butyl ester (パ one Block チ Le PV) of the methyl methacrylate of the prepolymer (3) of 150 mass parts, 150 mass parts, 3 mass parts, 20 mass parts, makes suspension.Under stirring condition, suspension was warmed up to 55 ℃ of reactions after 5 hours, it is warmed up to 100 ℃ with the time more than 1 hour, uses the azeotropic method separation of methylbenzene, after the cooling, carry out Separation of Solid and Liquid, clean, dry, classification, and obtain acrylated polyurethane resin particle (III).The mean grain size of this particle is 6 μ m, and the content of hardening catalyst approximately is 0.04 quality %.

Synthesis example 4

Adopt and method that synthesis example 1 is same, after two lauric acid tin octylates of the HDI of the polycaprolactone glycol (プ ラ Network セ Le L212AL) of 15 mass parts, 75 mass parts, 0.09 mass parts are reacted, add the toluene of lactone sex change (methyl) acrylate (プ ラ Network セ Le FM3) of 15 mass parts, poly-alkylene ethylene glycol (methyl) acrylate of 30 mass parts (Block レ Application マ one E, Japanese grease society make) and 34 mass parts, 80 ℃ of reactions down, obtain the prepolymer that nonvolatile component is 80 quality % (4).

The methylcellulose of sneaking into 1000 mass parts in the separable flask that has stirrer is 3% water, stir on one side, one side adds the solution by the peroxidating trimethylace tonitric tert-butyl ester (the パ one Block チ Le PV) formation of the n-BMA of the methyl methacrylate of the prepolymer (4) of 150 mass parts, 180 mass parts, 15 mass parts, 4 mass parts, makes suspension.Under stirring condition, suspension was warmed up to 55 ℃ of reactions after 5 hours, it is warmed up to 100 ℃ with the time more than 1 hour, uses the azeotropic method separation of methylbenzene, after the cooling, carry out Separation of Solid and Liquid, clean, dry, classification, and obtain acrylated polyurethane resin particle (IV).The mean grain size of this particle is 6 μ m, and the content of hardening catalyst approximately is 0.03 quality %.

Synthesis example 5

Do not add dibutyl tin laurate in the tramp material in synthesis example 1, in nitrogen environment, under 120 ℃ condition, reacted while stirring 24 hours, after the cooling, add toluene, obtain the prepolymer that nonvolatile component is 90 quality (5), can obtain acrylated polyurethane resin particle (V) according to the method identical then with synthesis example 1.The mean grain size of this particle is 16 μ m.

Embodiment 1: the modulation process that is used as the coating a of light diffusion layer

Toluene 250 mass parts

Cyclohexanone 40 mass parts

Acrylated polyurethane resin particle (I) 125 mass parts

Acrylic polyol (ア Network リ デ イ Star Network WDU-938, the hydroxyl value 50 in solid constituent 50%, the solid constituent, big Japanese イ Application キ chemical industry society make) 100 mass parts

Polyisocyanate (the effective NCO content in the solid constituent is 17% for コ ロ ネ-ト HL, solid constituent 75%, HDI class, Japanese Port リ ゥ レ Application industry society make) 15 mass parts

Above material is mixed with dispersator, obtain coating a as light diffusion layer.At this moment, the equivalent proportion of the relative hydroxyl of isocyanates is 1.0.Even coating a is that 25 ℃, humidity are to leave standstill 8 hours in 60% the environment in temperature, viscosity can not take place yet raise.

Used thickness be polyethylene terephthalate (PET) film of 100 μ m as base material, in its one side, the above-mentioned coating a as light diffusion layer that coats makes its dry film thickness be approximately 30 μ m, obtains the dry coating of light diffusion layer after the heated-air drying.After coating process finished, the heat aging of carrying out in 40 ℃ constant temperature enclosure 48 hours was handled and is made optical diffusion film.

Embodiment 2: the modulation process that is used as the coating b of light diffusion layer

Toluene 250 mass parts

Cyclohexanone 40 mass parts

Acrylated polyurethane resin particle (II) 125 mass parts

Acrylic polyol (ア Network リ デ イ Star Network WDU-938) 100 mass parts

Polyisocyanate (コ ロ ネ-ト HL) 15 mass parts

Above material is mixed with the dispersion stirrer, obtain coating b as light diffusion layer.At this moment, the equivalent proportion of the relative hydroxyl of isocyanates is 1.0.After coating process finished, the heat aging of carrying out in 40 ℃ constant temperature enclosure 48 hours was handled.

Use above-mentioned coating b as light diffusion layer to come the coating a as light diffusion layer in the alternate embodiment 1, adopt the method identical with embodiment 1 then, the formation dry coating is made optical diffusion film on base material.

Embodiment 3: the modulation process that is used as the coating c of light diffusion layer

Toluene 300 mass parts

Cyclohexanone 55 mass parts

Acrylated polyurethane resin particle (III) 150 mass parts

Acrylic polyol (ア Network リ デ イ Star Network WDU-938) 100 mass parts

Polyisocyanate (コ ロ ネ-ト HL) 30 mass parts

Above material is mixed with dispersator, obtain coating c as light diffusion layer.At this moment, the equivalent proportion of the relative hydroxyl of isocyanates is 2.0.After coating process finished, the heat aging of carrying out in 40 ℃ constant temperature enclosure 48 hours was handled.

Use above-mentioned coating c as light diffusion layer to come the coating a as light diffusion layer in the alternate embodiment 1, make dry film thickness be approximately 15 μ m, adopt the method identical with embodiment 1 then, the formation dry coating is made optical diffusion film on base material.

Comparative example 1: the modulation process that is used as the coating d of light diffusion layer

Toluene 250 mass parts

Cyclohexanone 40 mass parts

The acryl resin particle (MBX-15, the about 13 μ m of mean grain size do not contain hardening catalyst, ponding changes into the industrial society of product and makes) 125 mass parts

Acrylic polyol (ア Network リ デ イ Star Network WDU-938) 100 mass parts

Polyisocyanate (コ ロ ネ-ト HL) 15 mass parts

Above material is mixed with dispersator, obtain coating d as light diffusion layer.At this moment, the equivalent proportion of the relative hydroxyl of isocyanates is 1.0.

Use above-mentioned coating d as light diffusion layer to come the coating a as light diffusion layer in the alternate embodiment 1, make dry film thickness be approximately 29 μ m, adopt the method identical with embodiment 1 then, the formation dry coating is made optical diffusion film on base material.

Comparative example 2: the modulation process that is used as the coating e of light diffusion layer

Toluene 300 mass parts

Cyclohexanone 55 mass parts

The styrene resin particle (SBX-6, the about 6 μ m of mean grain size do not contain hardening catalyst, ponding changes into the industrial society of product and makes) 150 mass parts

Acrylic polyol (ア Network リ デ イ Star Network WDU-938) 100 mass parts

Polyisocyanate (コ ロ ネ-ト HL) 30 mass parts

Above material is mixed with dispersator, obtain coating d as light diffusion layer.At this moment, the equivalent proportion of the relative hydroxyl of isocyanates is 2.0.

Use above-mentioned coating e as light diffusion layer to come the coating a as light diffusion layer in the alternate embodiment 1, make dry film thickness be approximately 15 μ m, adopt the method identical with embodiment 1 then, the formation dry coating is made optical diffusion film on base material.

Comparative example 3: the modulation process that is used as the coating f of light diffusion layer

Toluene 290 mass parts

Cyclohexanone 50 mass parts

Dibutyl tin laurate 0.2 mass parts

The silicones resin particle (ト リ パ-Le 2000B, the about 6 μ m of mean grain size do not contain hardening catalyst, the シ リ コ of GE Toshiba-Application society makes) 150 mass parts

Acrylic polyol (ア Network リ デ イ Star Network WDU-938) 100 mass parts

Polyisocyanate (コ ロ ネ-ト HL) 15 mass parts

Above material is mixed with dispersator, obtain coating f as light diffusion layer.At this moment, the equivalent proportion of the relative hydroxyl of isocyanates is 1.0.

Use above-mentioned coating f as light diffusion layer to come the coating a as light diffusion layer in the alternate embodiment 1, make dry film thickness be approximately 15 μ m, adopt the method identical with embodiment 1 then, the formation dry coating is made optical diffusion film on base material.

Comparative example 4

Use acrylated polyurethane resin particle (V) to come acrylated polyurethane resin particle (I) in the alternate embodiment 1, adopt the method identical with embodiment 1 then, the formation dry coating is made optical diffusion film on base material.

The evaluation of the deciduous of resin particle

Adopting superficiality testing machine サ ゥ ザ ラ Application De ラ Block テ ス (the smart mechanism of Japan is done society of institute and made), fixedly make the light diffusion layer face rub each other optical diffusion film, is reciprocal 1000 light diffusingsurfaces that rub under the condition of 18N in loading.After the friction, downcut square, with the state that comes off of the resin particle of microscopic examination light diffusion layer face in the 10mm size of the optical diffusion film of downside friction.Following standard is adopted in the evaluation of resin particle deciduous.

Zero ... do not observe the place that comes off

△ ... come off the place be 1～3

* ... come off the place be more than 4

Evaluation result is as shown in table 1.As can be seen from Table 1, use when containing the resin particle of hardening catalyst, resin particle is difficult for falling from the light diffusion layer emaciated face, is highly suitable for optical diffusion film.And when adding hardening catalyst in coating, not only mar resistance is undesirable, and the easy quick-gelatinizing of coating, can not get ideal results in actual use.

The mar resistance evaluation of light diffusion layer

Adopting the spherical pressure of stainless steel pearl by superficiality testing machine HEIDON-14D (new Dong Kexueshe makes), is reciprocal 50 light diffusingsurfaces that rub under the 60mm/ condition of second in 20gf loading, translational speed.After friction,,, transmitted light is carried out visual observations with the light diffusingsurface up from the light of its back side illuminaton fluorescent light, and under fluorescent light direct irradiation light diffusingsurface, the reflected light on surface is carried out visual observations.Evaluation result is as shown in table 1.To the evaluation of damage, adopt following standard to estimate.

Zero ... carry out visual observations to seeing through light and surface reflection, all do not find damage.

△ ... the visual observations that sees through light is not found damage, and the catoptrical visual observations in surface is found to have damage.

* ... carry out visual observations to seeing through light and surface reflection, find all to have damage.

Evaluation result is as shown in table 1.As can be seen from Table 1, when use contained the resin particle of hardening catalyst, mar resistance was best.

The evaluation of optical characteristics

Use ヘ イ ズ メ--NDH2000 (Japanese electric look society make), measure the total light transmittance and the mist degree of optical diffusion film.Evaluation result is as shown in table 1.As can be seen from Table 1, even use the resin particle that contains hardening catalyst, do not observe the different of photopermeability and light diffusing yet.

Table 1

From table 1, can obviously find out the embodiment 1～embodiment 3 that uses acrylated polyurethane resin particle, have good mar resistance and anti-deciduous with hardening catalyst.The resin particle of comparative example 1～comparative example 3 is compared with embodiment 1～embodiment 3, and mar resistance descends as can be seen, and anti-deciduous significantly reduces.Even as comparative example 3, in coating, add hardening catalyst, anti-deciduous is not improved yet.And use does not contain the comparative example 4 of the acrylated polyurethane resin particle of hardening catalyst, and the embodiment 1～embodiment 3 that contains the acrylated polyurethane resin particle of hardening catalyst with use compares, and its mar resistance and anti-deciduous descend as can be seen.

Below, for the composition of the resin glue that contains the pure and mild isocyanates of acrylic acid multielement, can on the basis of adding back layer, study characteristics such as mar resistance and anti-deciduous the equivalent of hydroxyl recently being formed light diffusion layer by changing isocyanates.

Embodiment 4: the modulation process that is used as the coating g of light diffusion layer

Toluene 278 mass parts

Acrylated polyurethane resin particle (IV) 137 mass parts

Acrylic polyol (ア Network リ デ イ Star Network-801-P, solid constituent 50%, the hydroxyl value 100 of solid constituent, big Japanese イ Application キ chemical industry society makes) 100 mass parts

Polyisocyanate (コ ロ ネ-ト HL) 55 mass parts

Above material is mixed with dispersator, obtain coating g as light diffusion layer.At this moment, the equivalent proportion of the relative hydroxyl of isocyanates is 1.9, and with respect to the solid constituent of the resinoid bond (acrylic polyol+polyisocyanate) of 100 mass parts, the amount of being used of photodiffusion material (acrylated polyurethane resin particle) is 150 mass parts.

Be used as the modulation process of the coating h of back layer

Toluene 120 mass parts

Acryl resin (レ イ ヨ Application society of Mitsubishi makes for ダ イ ヤ Na-Le BR-80, solid constituent 100%, no hydroxyl value) 10 mass parts

Charged preventor (the first industrial pharmacy society makes for カ チ オ-ゲ Application ES-L-9, cationic surfactant) 0.5 mass parts

Lubricant (volume average particle size 10 μ m combine and grind the manufacturing of chemical society for ケ ミ ス ノ-MR-10HG, acryl resin particle) 0.2 mass parts

In above-mentioned material, earlier the toluene of whole acryl resins and 40 mass parts is stirred fully dissolving with dispersator after, append remaining material again, after mixing with dispersator, obtain coating h as back layer.

The coating of base material, drying, hardening process

Used thickness be polyethylene terephthalate (PET) film of 100 μ m as base material, above-mentioned coating g as light diffusion layer is coated on its face, making its dry film thickness is 16 μ m, carries out the dry coating that heated-air drying obtains light diffusion layer again.Above-mentioned coating h as back layer is coated on its another face, and making its dry film thickness is 2 μ m, carries out the dry coating that heated-air drying obtains back layer again.In order to promote sclerous reaction, after the coating process as light diffusion layer g and CB coating h finishes, in 40 ℃ constant temperature enclosure, preserve and made optical diffusion film in 48 hours.

Embodiment 5: the modulation process that is used as the coating i of light diffusion layer

Toluene 393 mass parts

Acrylated polyurethane resin particle (IV) 181 mass parts

Acrylic polyol (ダ イ ヤ Na-Le LR-1532) 100 mass parts

Polyisocyanate (コ ロ ネ-ト HL) 81 mass parts

Above material is mixed with dispersator, obtain coating i as light diffusion layer.At this moment, the equivalent proportion of the relative hydroxyl of isocyanates is 2.8, and with respect to the solid constituent of the resinoid bond (acrylic polyol+polyisocyanate) of 100 mass parts, the amount of being used of photodiffusion material (acrylated polyurethane resin particle) is 150 mass parts.

Then, use above-mentioned coating i as light diffusion layer to replace coating g among the embodiment 4, adopt the method identical, on base material, form dry coating, make optical diffusion film with embodiment 1 as light diffusion layer.

Embodiment 6: the modulation process that is used as the coating j of light diffusion layer

Toluene 175 mass parts

Acrylated polyurethane resin particle (IV) 91 mass parts

Acrylic polyol (100 mass parts of ア Network リ デ イ Star Network-801-P)

Polyisocyanate (コ ロ ネ-ト HL) 14 mass parts

Above material is mixed with dispersator, obtain coating j as light diffusion layer.At this moment, the equivalent proportion of the relative hydroxyl of isocyanates is 0.5, and with respect to the solid constituent of the resinoid bond (acrylic polyol+polyisocyanate) of 100 mass parts, the amount of being used of photodiffusion material (acrylated polyurethane resin particle) is 150 mass parts.

Then, use above-mentioned coating j as light diffusion layer to replace coating g among the embodiment 4, adopt the method identical, on base material, form dry coating, make optical diffusion film with embodiment 4 as light diffusion layer.

Comparative example 5: the modulation process that is used as the coating k of light diffusion layer

Toluene 278 mass parts

Acryl resin particle (ケ ミ ス ノ-MR-7HG, volume average particle size is about 6 μ m, combines and grinds the manufacturing of chemical society) 137 mass parts

Acrylic polyol (100 mass parts of ア Network リ デ イ Star Network-801-P)

Polyisocyanate (コ ロ ネ-ト HL) 55 mass parts

Above material is mixed with dispersator, obtain coating k as light diffusion layer.At this moment, the equivalent proportion of the relative hydroxyl of isocyanates is 1.9, and with respect to the solid constituent of the resinoid bond (acrylic polyol+polyisocyanate) of 100 mass parts, the amount of being used of photodiffusion material (acryl resin particle) is 150 mass parts.

Then, use above-mentioned coating k as light diffusion layer to replace coating g among the embodiment 4, adopt the method identical, on base material, form dry coating, make optical diffusion film with embodiment 4 as light diffusion layer.

Comparative example 6: the modulation process that is used as the coating 1 of light diffusion layer

Toluene 278 mass parts

Silicones resin particle (KMP-701, volume average particle size is about 3.5 μ m, the シ リ コ of SHIN-ETSU HANTOTAI-Application society and makes) 137 mass parts

Acrylic polyol (100 mass parts of ア Network リ デ イ Star Network-801-P)

Polyisocyanate (コ ロ ネ-ト HL) 55 mass parts

Above material is mixed with dispersator, obtain coating 1 as light diffusion layer.At this moment, the equivalent proportion of the relative hydroxyl of isocyanates is 1.9, and with respect to the solid constituent of the resinoid bond (acrylic polyol+polyisocyanate) of 100 mass parts, the amount of being used of photodiffusion material (silicones particle) is 150 mass parts.

Then, use above-mentioned coating 1 as light diffusion layer to replace coating g among the embodiment 4, adopt the method identical, on base material, form dry coating, make optical diffusion film with embodiment 4 as light diffusion layer.

Comparative example 7: the modulation process that is used as the coating m of light diffusion layer

Toluene 278 mass parts

The styrene resin particle (テ Network Port リ マ-SBX-6, volume average particle size is about 6 μ m, ponding changes into the industrial society of product and makes) 137 mass parts

Acrylic polyol (100 mass parts of ア Network リ デ イ Star Network-801-P)

Polyisocyanate (コ ロ ネ-ト HL) 55 mass parts

Above material is mixed with dispersator, obtain coating m as light diffusion layer.At this moment, the equivalent proportion of the relative hydroxyl of isocyanates is 1.9, and with respect to the solid constituent of the resinoid bond (acrylic polyol+polyisocyanate) of 100 mass parts, the amount of being used of photodiffusion material (styrene resin particle) is 150 mass parts.

Then, use above-mentioned coating m as light diffusion layer to replace coating g among the embodiment 4, adopt the method identical, on base material, form dry coating, make optical diffusion film with embodiment 4 as light diffusion layer.

Comparative example 8: the modulation process that is used as the coating n of light diffusion layer

Toluene 840 mass parts

Acryl resin (ダ イ ヤ Na-Le BR-80, solid constituent 100%, no hydroxyl value, レ イ ヨ Application society of Mitsubishi makes) 100 mass parts

Acrylated polyurethane resin particle (IV) 120 mass parts

In above-mentioned material, remaining material is appended after using the dispersion stirrer to stir abundant the dissolving toluene of whole acryl resins and 400 mass parts again by elder generation, after mixing with dispersator, obtains being used as the coating n of light diffusion layer.With respect to the solid constituent of the resinoid bond (acryl resin) of 100 mass parts, the amount of being used of photodiffusion material (acrylated polyurethane resin particle) is 120 mass parts.

Then, use above-mentioned coating n as light diffusion layer to replace coating g among the embodiment 4, adopt the method identical, on base material, form dry coating, make optical diffusion film with embodiment 4 as light diffusion layer.

The evaluation of the mar resistance of light diffusion layer

Superficiality testing machine by identical with being used for embodiment 1～3, comparative example 1～4 uses stainless steel ball to press pearl, is under the 60mm/ condition of second in 5gf loading, translational speed, reciprocal 50 light diffusingsurfaces that rub.The standard identical to evaluation employing and the embodiment 1～3 of damage, comparative example 1～4.

Evaluation result is as shown in table 2.From table 2 kind as can be seen, when using the acrylated polyurethane resin particle, mar resistance is best.

The solvent resistance evaluation of light diffusion layer

Use toluene: the wetting continuous rod of the mixed solvent of methyl ethyl ketone=1:1, with this continuous rod friction light diffusion layer.With in the table 2 fixed number of times when rubbing, adopt following standard to estimate and estimate.

Zero ... do not see that light diffusion layer changes

△ ... light diffusion layer has partly soluble vestige

* ... light diffusion layer peels off and exposes substrate surface

Evaluation result is as shown in table 2.

The evaluation of the deciduous of resin particle

By the superficiality testing machine identical,, examine under a microscope the state that comes off of the resin particle of light diffusion layer face with same method with being used for embodiment 1～3, comparative example 1～4.Evaluation result is as shown in table 2, the standard identical to the evaluation employing and the embodiment 1～3 of the deciduous of resin particle, comparative example 1～4.

Table 2

As can be seen from Table 2, the acrylated polyurethane resin particle in the resinoid bond of light diffusion layer is not when containing isocyanates, and mar resistance, solvent resistance, anti-deciduous all reduce, and particularly solvent resistance and anti-deciduous significantly reduce.If as embodiment 4, embodiment 5, the ratio of isocyanates/hydroxyl is in 0.7～3.0 the scope of application, and solvent resistance and anti-deciduous can be very desirable.Even in the scope of the suitable ratio of mentioning in the above, under the situation of silicon resin particle and styrene resin particle, this two aspects character of mar resistance and anti-deciduous is also very low.

Below, the mar resistance of optical diffusion film and anti-deciduous etc. to be studied, the optical diffusion film of employing is the optical diffusion film when using as cementing agent with the resin that polyisocyanate cross-linked polyester polyvalent alcohol obtains.

Embodiment 7: the modulation process that is used as the coating o of light diffusion layer

Toluene 765 mass parts

Cyclohexanone 255 mass parts

Acrylated polyurethane resin particle (I) 385 mass parts

Polyester polyol (バ-ノ Star Network D6-439, solid constituent 80%, the hydroxyl value 140 of solid constituent, big Japanese イ Application キ chemical industry society makes) 150 mass parts

Polyisocyanate (バ-ノ Star Network DN-950, solid constituent 75%, the HDI class, the effective NCO content 13% in the solid constituent, big Japanese イ Application キ chemical industry society makes) 95 mass parts

Above material is mixed with dispersator, obtain coating o as light diffusion layer.At this moment, isocyanates is 0.7 with respect to the equivalent proportion of hydroxyl.

Used thickness be polyethylene terephthalate (PET) film of 100 μ m as base material, coat above-mentioned coating o in its one side as light diffusion layer, make its dry film thickness be about 27 μ m, obtain the dry coating of light diffusion layer after the heated-air drying.After coating process finished, the heat aging of carrying out in 40 ℃ constant temperature enclosure 48 hours was handled and is made optical diffusion film.

Embodiment 8: the modulation process that is used as the coating p of light diffusion layer

Toluene 765 mass parts

Cyclohexanone 255 mass parts

Acrylated polyurethane resin particle (II) 385 mass parts

Polyester polyol (バ-ノ Star Network D6-439) 150 mass parts

Polyisocyanate (バ-ノ Star Network DN-950) 95 mass parts

Above material is mixed with dispersator, obtain coating p as light diffusion layer.At this moment, isocyanates is 0.7 with respect to the equivalent proportion of hydroxyl.

Use above-mentioned coating p as light diffusion layer to replace coating o among the embodiment 7, adopt the method identical, on base material, form dry coating, make optical diffusion film with embodiment 7 as light diffusion layer.

Embodiment 9: the modulation process that is used as the coating q of light diffusion layer

Toluene 850 mass parts

Cyclohexanone 290 mass parts

Acrylated polyurethane resin particle (III) 235 mass parts

Polyester polyol (バ-ノ Star Network D6-439) 150 mass parts

Polyisocyanate (バ-ノ Star Network DN-950) 130 mass parts

Above material is mixed with dispersator, obtain coating q as light diffusion layer.At this moment, isocyanates is 1.0 with respect to the equivalent proportion of hydroxyl.

Use above-mentioned coating q as light diffusion layer to replace coating o among the embodiment 7, and make its dry film thickness be about 13 μ m, adopt the method identical, on base material, form dry coating, make optical diffusion film with embodiment 7 as light diffusion layer.

Comparative example 9: the modulation process that is used as the coating r of light diffusion layer

Toluene 500 mass parts

MEK 375 mass parts

Cyclohexanone 75 mass parts

The styrene resin particle (SBX-12, mean grain size is about 12 μ m, does not contain hardening catalyst, ponding changes into the industrial society of product and makes) 275 mass parts

Vibrin (hydroxyl value is 4 for エ リ-テ Le UE3600, solid state component 100%, and ユ ニ チ カ society makes) 125 mass parts

Polyisocyanate (バ-ノ Star Network DN-950) 10 mass parts

Above material is mixed with dispersator, obtain coating q as light diffusion layer.At this moment, isocyanates is 3.4 with respect to the equivalent proportion of hydroxyl.

Use above-mentioned coating r as light diffusion layer to replace coating o among the embodiment 7, and make its dry film thickness be about 24 μ m, adopt the method identical, on base material, form dry coating, make optical diffusion film with embodiment 7 as light diffusion layer.

Comparative example 10: the modulation process that is used as the coating s of light diffusion layer

Toluene 900 mass parts

Cyclohexanone 120 mass parts

Silicones particle (ト ス パ-Le 2000B) 150 mass parts

Acryl resin (ダ イ ヤ Na-Le BR-85, solid state component 100%, no hydroxyl value, レ イ ヨ Application society of Mitsubishi makes) 72 mass parts

Polyisocyanate (バ-ノ Star Network DN-950) 10 mass parts

Above material is mixed with dispersator, obtain coating s as light diffusion layer.

Use above-mentioned coating s as light diffusion layer to replace coating o among the embodiment 7, and make its dry film thickness be about 13 μ m, adopt the method identical, on base material, form dry coating, make optical diffusion film with embodiment 7 as light diffusion layer.

Comparative example 11: the modulation process that is used as the coating t of light diffusion layer

Toluene 810 mass parts

Cyclohexanone 150 mass parts

Dibutyl tin laurate 0.5 mass parts

The acryl resin particle (MBX-20, the about 17 μ m of mean grain size do not contain hardening catalyst, ponding changes into the industrial society of product and makes) 315 mass parts

Acrylic polyol (265 mass parts of ア Network リ デ イ Star Network-801-P)

Polyisocyanate (バ-ノ Star Network DN-950) 36 mass parts

Above material is mixed with dispersator, obtain coating t as light diffusion layer.At this moment, isocyanates is 0.4 with respect to the equivalent proportion of hydroxyl.

Use above-mentioned coating t as light diffusion layer to replace coating o among the embodiment 7, and make its dry film thickness be about 30 μ m, adopt the method identical, on base material, form dry coating, make optical diffusion film with embodiment 7 as light diffusion layer.

Comparative example 12: the modulation process that is used as the coating u of light diffusion layer

Toluene 765 mass parts

Cyclohexanone 255 mass parts

Acryl resin particle (MBX-20) 385 mass parts

Polyester polyol (バ-ノ Star Network D6-439) 150 mass parts

Polyisocyanate (バ-ノ Star Network DN-950) 95 mass parts

Above material is mixed with dispersator, obtain coating u as light diffusion layer.At this moment, isocyanates is 0.7 with respect to the equivalent proportion of hydroxyl.

Use above-mentioned coating u as light diffusion layer to replace coating o among the embodiment 7, and make its dry film thickness be about 30 μ m, adopt the method identical, on base material, form dry coating, make optical diffusion film with embodiment 7 as light diffusion layer.

Comparative example 13

Use acrylated polyurethane resin particle (V) to come acrylated polyurethane resin particle (I) in the alternate embodiment 7, adopt the method identical with embodiment 7 then, the formation dry coating is made optical diffusion film on base material.

To containing the optical diffusion film of the light diffusion layer of record in embodiment 7～9, the comparative example 9～13, carry out following evaluation.

The deciduous evaluation of resin particle

Employed identical in the superficiality testing machine that adopts and embodiment 1～6, the comparative example 1～8, with identical method, examine under a microscope the state that comes off of the resin particle of light diffusion layer face.Evaluation result is as shown in table 3.Evaluation institute accepted standard to the deciduous of resin particle is identical with employed standard in embodiment 1～6, comparative example 1～8.

The mar resistance evaluation of light diffusion layer

The machine that is used to carry out scuff test in the superficiality testing machine that uses and embodiment 1～6, the comparative example 1～8 is identical, adopts the spherical pressure of stainless steel pearl, is under the 60mm/ condition of second in loading, the translational speed of 50gf, reciprocal 50 light diffusingsurfaces that rub.Observe the residual damage in friction back by estimating.Evaluation to damage in the table is adopted and the identical standard that is used for embodiment 1～6, comparative example 1～8.

The evaluation of optical characteristics

Adopt and embodiment 1～3, comparative example 1～4 employed identical method, measure the total light transmittance and the mist degree of optical diffusion film.Evaluation result is as shown in table 3.

Table 3

From table 3 kind as can be seen, use the embodiment 7～embodiment 9 of the acrylated polyurethane resin particle that contains hardening catalyst, also have mar resistance and anti-deciduous having good mist degree and see through on the basis of filter.Compare with the acrylated polyurethane resin particle, styrene resin particle in the comparative example 9, the mar resistance of the acryl resin particle in the comparative example 11,12 is low, and the whole resin particle in the comparative example 9～13 is not because contain hardening catalyst, and its anti-deciduous is low.Even as comparative example 11, in coating, add hardening catalyst, its anti-deciduous also fails to improve.

Industrial application

Optical diffusion film among the present invention can provide a kind of being difficult for to come off from resinoid bond generation resin particle Light diffusion layer, this is because use and contain third of hardening catalyst in the resinoid bond of light diffusion layer Olefin(e) acid polyurethane resin particle is as photodiffusion material, but the above-mentioned poly-isocyanide of this hardening catalyst catalysis The cross-linking reaction of acid esters, and, use through PIC cross-linked acrylic acid polyalcohol or PEPA The copolymer that produces is as resinoid bond, so, at the interface of resin particle and resinoid bond, resin The cross-linking reaction of binding agent is preferential also carries out fast. Acrylated polyurethane resin particle self and existing third Olefin(e) acid resin particle, styrene resin particle etc. are compared, and have good marresistance, and, because make Be easy to obtain hardness of film by the crosslinked copolymer that obtains of PIC as resinoid bond, so not Easily to light diffusion layer face injury. And the amount of the hardening catalyst of interpolation is not added obstruction light to Learn the degree of characteristic, so, light transmission and the light diffusing identical with existing optical diffusion film can be kept.

Claims (6)

1. optical diffusion film, it is characterized in that, on at least one face of transparent flat substrates, be provided with resin particle and be dispersed in light diffusion layer in the resinoid bond, described resinoid bond is through polyisocyanate cross-linked acrylic acid polyvalent alcohol or polyester polyol and the multipolymer that forms, and described resin particle is the acrylated polyurethane resin particle that contains hardening catalyst, and described hardening catalyst is the catalyzer of the cross-linking reaction that caused by described polyisocyanate in the described resinoid bond.

2. the optical diffusion film of putting down in writing as claim 1, it is characterized in that, described multipolymer by acrylic polyol after polyisocyanate is crosslinked and obtain, and, contain the acrylic monomers unit with hydroxyl of inscape of the described acrylic polyol of conduct of 1～50 quality %.

3. as claim 1 or 2 optical diffusion films of being put down in writing, it is characterized in that described hardening catalyst contains dibutyl tin laurate or two lauric acid tin octylates.

4. the optical diffusion film of putting down in writing as claim 3 is characterized in that, with respect to described acrylated polyurethane resin particle, the content of described hardening catalyst is 0.0001～0.5 quality %.

5. as claim 1 or 2 optical diffusion films of being put down in writing, it is characterized in that the hydroxyl value of described acrylic polyol is more than 25 below 500, the isocyanates in the described polyisocyanate is 0.7～3.0 with respect to the equivalent proportion of the hydroxyl in the described acrylic polyol.

6. the optical diffusion film of putting down in writing as claim 1, it is characterized in that, it is crosslinked and obtain through polyisocyanate that described multipolymer is a polyester polyol, and, the hydroxyl value of described polyester polyol is more than 5 below 300, and the isocyanates in the described polyisocyanate is 0.7～3.0 with respect to the equivalent proportion of the hydroxyl in the described polyester polyol.

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