JP2006193675A - Method for producing laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a laminated film having sufficiently high adhesiveness by uniformly curing an ultraviolet curable resin in high efficiency without causing the deformation of the substrate film. <P>SOLUTION: The laminated film is produced by applying an ultraviolet curable resin to one surface of a substrate film (A) composed of a transparent resin to form a film (B), irradiating the film (B) at the side opposite to the coated side with ultraviolet rays at an accumulated light quantity of 50-400 mJ/cm<SP>2</SP>to cure the UV curable resin, and irradiating the coated side of the film (B) with ultraviolet rays while keeping the temperature difference between the coated side and the uncoated side to ≤30°C to proceed the curing of the UV curable resin. The invention further relates to the production method of the laminated film. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a laminated film, and more specifically, an ultraviolet curable resin is efficiently and uniformly cured without deforming a base film, and there is no discoloration or cracking and the laminated film has excellent adhesion. It relates to a method of manufacturing.

  A method of forming a laminated film by applying an ultraviolet curable resin to a resin film and irradiating the surface with ultraviolet rays to cure the curable resin is well known. The laminated film obtained by such a method is used, for example, as an optical film used for a liquid crystal display device, a plasma display or the like, or as a packaging film. It is also used in various applications such as automobile parts and electrical / electronic parts.

In the method of producing a laminated film by curing an ultraviolet curable resin formed on a resin film with an ultraviolet irradiation lamp, the resin film is easily deformed by heat from the lamp, and the adhesion between the ultraviolet curable resin and the resin film is low. There is a problem.
In order to solve this problem, first, ultraviolet rays are irradiated on the surface opposite to the application surface of the ultraviolet curable resin formed on the resin film, and then the ultraviolet ray is irradiated on the application surface to thereby apply the ultraviolet curable resin. A method of curing is disclosed (Patent Document 1).
According to this method, it is said that a cured film with less curling due to curing shrinkage and thermal deformation can be formed. However, it is difficult to fix the film when irradiating the surface opposite to the application surface of the ultraviolet curable resin. As a result, it becomes difficult to uniformly irradiate the film with ultraviolet rays, the degree of curing tends to be uneven in the thickness direction of the coating film, and the adhesion between the curable resin layer and the substrate film is not sufficiently high. In addition, when the illuminance of ultraviolet rays is increased, cracks occur in the cured coating, and the film may be deformed by the heat of the ultraviolet lamp.

JP 2001-205179 A

  The present invention has been made in view of the situation of the prior art, and is a laminated film that cures an ultraviolet curable resin efficiently and uniformly without deforming the film, has no discoloration or cracking, and has sufficiently high adhesion. It is to provide a manufacturing method.

The inventors of the present invention irradiate the surface of the film opposite to the application surface of the ultraviolet curable resin with ultraviolet rays having an accumulated light quantity of 50 to 400 mJ / cm ² and then opposite the application surface of the film and the application surface. The heat adjusted by irradiating the coated surface with ultraviolet rays under the condition that the temperature difference from the surface of the transparent resin is 30 ° C. or less, or adjusted to within the glass transition temperature of the transparent resin, 40 ° C. or more, and ± 3 ° C. variation range It has been found that the above-mentioned problems can be solved by bringing the film into contact with a support whose temperature has been adjusted with a medium and irradiating the application surface with ultraviolet rays, and the present invention has been completed.

Thus, according to the present invention, an ultraviolet curable resin is applied to one side of the base film (A) made of a transparent resin to obtain a film (B), and on the surface opposite to the coated surface of the film (B). The ultraviolet curable resin is cured by irradiating with an ultraviolet ray having an accumulated light quantity of 50 to 400 mJ / cm ² , and then the temperature difference between the coated surface of the film (B) and the opposite surface is 30 ° C. or less. The method for producing a laminated film in which the application surface of the film (B) is irradiated with ultraviolet rays under the conditions of, and the ultraviolet curable resin is further cured, and
An ultraviolet curable resin is applied to one side of the base film (A) made of a transparent resin to obtain a film (B), and an integrated amount of ultraviolet light of 50 to 400 mJ is applied to the surface opposite to the coated surface of the film (B). / Cm ² of ultraviolet light is cured to cure the ultraviolet curable resin, and then the surface opposite to the coated surface of the film (B) is brought into contact with a support whose temperature is adjusted with a heat medium under the following conditions: There is provided a method for producing a laminated film in which an application surface of the film (B) is irradiated with light with an ultraviolet lamp to further cure the ultraviolet curable resin.
(1) The temperature of the heating medium for adjusting the temperature of the support is 40 ° C. or higher and not higher than the glass transition temperature of the transparent resin.
(2) Temperature variation of the heating medium is within ± 3 ° C.

 According to the production method of the present invention, it is possible to efficiently and uniformly cure an ultraviolet curable resin without causing deformation of a base film, and to obtain a laminated film having high adhesion and no discoloration. it can. This laminated film has excellent scratch resistance due to the cured resin layer, and is suitable as an optical film used in a liquid crystal display device or the like.

In the method for producing a laminated film of the present invention, an ultraviolet curable resin is applied to one side of a base film (A) made of a transparent resin to obtain a film (B), which is opposite to the coated side of the film (B). The ultraviolet curable resin is cured by irradiating the surface of the film with ultraviolet rays having an accumulated light quantity of 50 to 400 mJ / cm ² , and then the temperature difference between the coated surface of the film (B) and the opposite surface is 30. The ultraviolet ray curable resin is further cured by irradiating the coating surface of the film (B) with ultraviolet rays under the condition of 0 ° C. or lower.
Moreover, the manufacturing method of another laminated | multilayer film of this invention is as follows.
An ultraviolet curable resin is applied to one side of the base film (A) made of a transparent resin to obtain a film (B), and an integrated amount of ultraviolet light of 50 to 400 mJ is applied to the surface opposite to the coated surface of the film (B). / Cm ² of ultraviolet light is cured to cure the ultraviolet curable resin, and then the surface opposite to the coated surface of the film (B) is brought into contact with a support whose temperature is adjusted with a heat medium under the following conditions: An ultraviolet lamp irradiates the application surface of the film (B) with light to further cure the ultraviolet curable resin.
(1) The temperature of the heating medium for adjusting the temperature of the support is 40 ° C. or higher and not higher than the glass transition temperature of the transparent resin.
(2) Temperature variation of the heating medium is within ± 3 ° C.

  The base film (A) used in the present invention is made of a transparent resin. The transparent resin is not particularly limited as long as it is a resin that transmits light, but is preferably a resin having a total light transmittance of 80% or more when formed into a 1 mm thick plate. Examples of the transparent resin constituting the base film include, for example, alicyclic structure-containing polymer resins, polyester polymer resins, cellulose polymer resins, polycarbonate polymer resins, polysulfone polymer resins, and polyether sulfone resins. Examples thereof include polymer resins, polystyrene polymer resins, polyolefin polymer resins, polyvinyl alcohol polymer resins, polyvinyl chloride polymer resins, and polymethacrylate polymer resins.

  Among these, alicyclic structure-containing polymer resins, cellulose polymer resins such as cellulose diacetate, cellulose triacetate, and cellulose acetate butyrate; polyester polymer resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; From the viewpoints of transparency, low hygroscopicity, dimensional stability, lightness, etc., alicyclic structure-containing polymer resins, triacetyl cellulose and polyethylene terephthalate are more preferable, and alicyclic structure-containing polymer resins are particularly preferable. preferable.

  The alicyclic structure-containing polymer resin has an alicyclic structure in the repeating unit of the polymer resin, and the polymer resin having an alicyclic structure in the main chain and an alicyclic structure in the side chain. Any polymer resin can be used.

  Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and a cycloalkane structure is preferable from the viewpoint of thermal stability. Although there is no restriction | limiting in particular in carbon number which comprises an alicyclic structure, Usually, 4-30 pieces, Preferably it is 5-20 pieces, More preferably, it is 5-15 pieces. When the number of carbon atoms constituting the alicyclic structure is in this range, a laminated film having excellent heat resistance and flexibility can be obtained.

  The proportion of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer resin may be appropriately selected according to the purpose of use, but is usually 50% by weight or more, preferably 70% by weight or more, more preferably. Is 90% by weight or more. When there are too few repeating units having an alicyclic structure, the heat resistance tends to decrease. In addition, repeating units other than the repeating unit which has an alicyclic structure in an alicyclic structure containing polymer resin are suitably selected according to the intended purpose.

  Specific examples of the alicyclic structure-containing polymer resin include norbornene polymers, monocyclic olefin polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers, and hydrides thereof. Is mentioned. Among these, norbornene-based polymers are preferable from the viewpoints of transparency and moldability.

  Norbornene-based polymers include ring-opening polymers of norbornene-based monomers, ring-opening copolymers of norbornene-based monomers and other monomers capable of ring-opening copolymerization, and attachment of norbornene-based monomers. Examples thereof include addition polymers, addition copolymers with other monomers copolymerizable with norbornene monomers, and hydrides thereof. Among these, from the viewpoint of transparency, a hydride of a ring-opening polymer of a norbornene monomer is particularly preferable.

The norbornene monomer, for example, bicyclo [2.2.1] hept-2-ene (common name: norbornene), tricyclo [4.3.0.1 ^{2, 5]} deca-3,7-diene (Common name: dicyclopentadiene), 7,8-benzotricyclo [4.3.0.1 ^2,5 ] dec-3-ene (common name: methanotetrahydrofluorene), tetracyclo [4.4.0. 1 ^2,5 . 1 ^7,10 ] dodec-3-ene (common name: tetracyclododecene), derivatives of these compounds (for example, those having a substituent in the ring), and the like. Here, examples of the substituent include an alkyl group, an alkylene group, an alkoxycarbonyl group, and a carboxyl group. In addition, these substituents may be the same or different and a plurality may be bonded to the ring. Norbornene monomers can be used alone or in combination of two or more.

  Other monomers capable of ring-opening copolymerization with norbornene monomers include, for example, monocyclic olefins such as cyclohexene, cycloheptene, and cyclooctene and derivatives thereof; cyclic conjugated dienes such as cyclohexadiene and cycloheptadiene; Derivatives thereof; and the like.

Ring-opening polymers of norbornene monomers and ring-opening copolymers of norbornene monomers and other monomers copolymerizable therewith are polymerized in the presence of a ring-opening polymerization catalyst. Can be obtained.
As the ring-opening polymerization catalyst, a commonly used known catalyst can be used.

  Other monomers that can be copolymerized with norbornene monomers include, for example, α-olefins having 2 to 20 carbon atoms such as ethylene and propylene, and derivatives thereof; cycloolefins such as cyclobutene and cyclopentene, and the like. Derivatives; non-conjugated dienes such as 1,4-hexadiene and the like. These monomers can be used alone or in combination of two or more. Among these, α-olefin is preferable, and ethylene is more preferable.

  Norbornene monomer addition polymers and addition copolymers of norbornene monomers and other monomers copolymerizable therewith are obtained by polymerizing the monomers in the presence of an addition polymerization catalyst. Obtainable. As the addition polymerization catalyst, a commonly used known catalyst can be used.

The hydride of the norbornene polymer can be obtained by hydrogenating the carbon-carbon unsaturated bond of the norbornene polymer preferably 90% or more in the presence of a known hydrogenation catalyst.

Examples of the monocyclic olefin-based polymer include addition polymers such as cyclohexene, cycloheptene, and cyclooctene.
Examples of the cyclic conjugated diene polymer include polymers obtained by 1,2-addition polymerization or 1,4-addition polymerization of cyclic conjugated diene monomers such as cyclopentadiene and cyclohexadiene.

  The vinyl alicyclic hydrocarbon polymer is a polymer having a repeating unit derived from vinylcycloalkane or vinylcycloalkene. Examples of vinyl alicyclic hydrocarbon polymers include polymers of vinyl alicyclic hydrocarbon compounds such as vinyl cycloalkanes such as vinyl cyclohexane and vinyl cycloalkenes such as vinyl cyclohexene and their hydrides; styrene, α- Examples thereof include a polymer obtained by polymerizing a vinyl aromatic hydrocarbon compound such as methylstyrene and hydrogenating an aromatic ring portion.

  The vinyl alicyclic hydrocarbon polymer contains a monomer unit of a vinyl alicyclic hydrocarbon compound and a monomer unit obtained by hydrogenating an aromatic ring of a vinyl aromatic hydrocarbon compound. Copolymers such as random copolymers and block copolymers of these monomer units with other monomer units copolymerizable may be used. Examples of the block copolymer include diblock, triblock, or more multiblock and gradient block copolymers, but are not particularly limited.

  The transparent resin has a polystyrene-reduced weight average molecular weight of usually 10,000 to 300,000, preferably 15, as measured by gel permeation chromatography using cyclohexane as a solvent (toluene if the resin does not dissolve). The range is from 20,000 to 250,000, more preferably from 20,000 to 200,000. A transparent resin having a weight average molecular weight in this range is suitable because it highly balances the mechanical strength and moldability of the base film.

  The transparent resin is not particularly limited by its molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)), but is usually in the range of 1 to 10, preferably 1 to 6, more preferably 1.1 to 4. It is. By adjusting the molecular weight distribution in such a range, the mechanical strength and molding processability of the base film are well balanced.

Moreover, various compounding agents can be added to the transparent resin as desired. The compounding agent is not particularly limited as long as it is usually used in thermoplastic resin materials. For example, antioxidants such as phenolic antioxidants, phosphoric acid antioxidants, sulfur antioxidants;
UV absorbers such as benzotriazole UV absorbers, benzoate UV absorbers, benzophenone UV absorbers, acrylate UV absorbers, metal complex UV absorbers;
Light stabilizers such as hindered amine light stabilizers; Colorants such as dyes and pigments;
Fatty alcohol esters, polyhydric alcohol esters, fatty acid amides, inorganic particles and other lubricants; triester plasticizers, phthalate ester plasticizers, fatty acid-basic ester plasticizers, oxyacid ester plasticizers, etc. An antistatic agent such as a fatty acid ester of a polyhydric alcohol;

The base film (A) used in the present invention can be obtained by molding the transparent resin into a film by a known molding method.
As the forming method, a melt extrusion molding method is preferable from the viewpoint that the content of volatile components in the film and uneven thickness can be reduced. Examples of the melt extrusion method include a method using a die such as a T die, an inflation method, and the like, but a method using a T die is preferable in terms of excellent productivity and thickness accuracy.

  Moreover, as a base film (A) used for this invention, what gave the surface modification process to the single side | surface or both surfaces can be used. By performing the surface modification treatment, the adhesion with the ultraviolet curable resin layer can be improved. Examples of the surface modification treatment include energy beam irradiation treatment and chemical treatment.

  Examples of the energy ray irradiation treatment include corona discharge treatment, plasma treatment, electron beam irradiation treatment, and ultraviolet ray irradiation treatment. From the viewpoint of processing efficiency, corona discharge treatment and plasma treatment are preferred, and corona discharge treatment is particularly preferred. Examples of the chemical treatment include a method of immersing in an oxidizing agent aqueous solution such as potassium dichromate solution or concentrated sulfuric acid and then washing with water.

  The thickness of the base film (A) is usually 5 to 300 μm, more preferably 40 to 200 μm. More preferably, it is 50-100 micrometers. When the thickness of the base film is within the above range, a base film excellent in durability, mechanical strength, scratch resistance and optical performance can be obtained.

  The ultraviolet curable resin used in the present invention is not particularly limited as long as it can form a cured film having a hardness of “HB” or higher in the pencil hardness test specified in JIS K5700. For example, organic silicone type, melamine type, epoxy type, acrylic type, urethane acrylate type and other ultraviolet curable organic materials; inorganic ultraviolet curable resin materials such as silicon dioxide; Among these, urethane acrylate-based or polyfunctional acrylate-based ultraviolet curable resin materials are preferable from the viewpoint of good adhesive force and excellent productivity.

  A suitable ultraviolet curable resin used in the present invention is a resin that contains a prepolymer, an oligomer and / or a monomer having a polymerizable unsaturated bond or an epoxy group in the molecule and is cured by ultraviolet irradiation.

  Examples of prepolymers and oligomers having a polymerizable unsaturated bond or epoxy group in the molecule include unsaturated polyesters such as a condensation product of unsaturated dicarboxylic acid and polyhydric alcohol; polyester methacrylate, polyether methacrylate, polyol methacrylate And methacrylates such as melamine methacrylate, polyester acrylates, epoxy acrylates, urethane acrylates, polyether acrylates, polyol acrylates, acrylates such as melamine acrylates, and cationic polymerization type epoxy compounds.

Examples of the monomer having a polymerizable unsaturated bond or epoxy group in the molecule include styrene monomers such as styrene and α-methylstyrene; methyl acrylate, ethyl acrylate, -2-ethylhexyl acrylate, methoxy acrylate Acrylic esters such as ethyl, butoxyethyl acrylate, butyl acrylate, methoxybutyl acrylate, and phenyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, methoxyethyl methacrylate, ethoxymethyl methacrylate, methacrylic acid Methacrylic acid esters such as phenyl and lauryl methacrylate; acrylic acid-2- (N, N-diethylamino) ethyl, acrylic acid-2- (N, N-dimethylamino) ethyl, acrylic acid-2- (N, N -Dibenzylamino) methyl, acrylic -2- (N, N- diethylamino) substituted amino alcohol esters of unsaturated substituent, such as propyl;
Unsaturated carboxylic acid amides such as acrylamide and methacrylamide;

Ethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, triethylene glycol diacrylate, dipropylene glycol diacrylate, ethylene glycol diacrylate, propylene glycol dimethacrylate, diethylene glycol dimethacrylate 2-hydroxy acrylate, 2-hexyl acrylate, phenoxyethyl acrylate, ethylene glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate Multifunctional Acrela such as REIT G
Polythiols having two or more thiol groups in the molecule, such as trimethylolpropane trithioglycolate, trimethylolpropane trithiopropylate, pentaerythritol tetrathioglycolate;
Glycidyl acrylate, glycidyl methacrylate, glycidyl phenyl ether, glycidyl ethyl ether, epichlorohydrin, allyl glycidyl ether, ethylene oxide, propylene oxide, neopentyl glycol diglycidyl ether, trimethylolpropane diglycidyl ether, glycerol diglycidyl ether, di Glycerol triglycidyl ether, diglycerol triglycidyl ether, pentaerythritol diglycidyl ether, pentaerythritol triglycidyl ether, diglycidyl ether of tris (2-hydroxyethyl) isocyanurate, phenol novolac polyglycidyl ether, cresol novolac polyglycidyl ether, etc. Epoxy compounds;
In the present invention, these prepolymers, oligomers and / or monomers can be used singly or in combination of two or more.

  The content of the prepolymer, oligomer and / or monomer in the ultraviolet curable resin used in the present invention is preferably 5% by weight to 95% by weight from the viewpoint of obtaining excellent coating suitability.

A suitable ultraviolet curable resin used in the present invention contains a photopolymerization initiator and a photopolymerization accelerator. As photopolymerization initiators, radical polymerization initiators such as acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether; aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, metathelone compounds, benzoin sulfonic acids Cationic polymerizable initiators such as esters; These can be used individually by 1 type or in combination of 2 or more types.
The amount of the photopolymerization initiator is usually 0.1 to 10 parts by weight in 100 parts by weight of the ultraviolet curable resin.

  The ultraviolet curable resin is usually applied as a liquid. Examples of the solvent that can be used in the coating liquid include alcohols such as methanol, ethanol, isopropanol, n-butanol, and isobutanol; ethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, diethylene glycol, diethylene glycol monobutyl ether Glycols such as diacetone glycol; aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as n-hexane and n-heptane; esters such as ethyl acetate and butyl acetate; methyl ethyl ketone and methyl isobutyl ketone Ketones; oximes such as methyl ethyl ketoxime; and combinations of two or more thereof; and the like.

  The method for applying the ultraviolet curable resin on the base film is not particularly limited, and a known application method can be employed. Examples of the coating method include a wire bar coating method, a dip method, a spray method, a spin coating method, a roll coating method, and a gravure coating method.

  Although the application amount of the ultraviolet curable resin is not particularly limited, the thickness after curing is usually 0.5 to 30 μm, preferably 3 to 15 μm, more preferably 5 to 10 μm.

  The ultraviolet curable resin may contain antioxidants, ultraviolet absorbers, light stabilizers, colorants such as dyes and pigments, plasticizers, lubricants, surfactants, antistatic agents and the like.

  In the present invention, ultraviolet irradiation is performed from both sides. Specifically, (1) an ultraviolet curable resin is applied to the base film (A) to obtain a film (B), and the surface opposite to the coated surface of the film (B) is irradiated with ultraviolet rays to be applied. The film is cured. (2) Next, the coated surface of the film (B) is irradiated with ultraviolet rays again to further cure the coating film. Thereby, a uniform ultraviolet curable resin layer can be formed on a base film (A).

In the step (1) of irradiating the surface opposite to the coated surface of the film (B) with ultraviolet rays, the ultraviolet rays are irradiated so that the integrated light quantity is 50 to 400 mJ / cm.
Examples of the method of irradiating the surface opposite to the coating surface of the film (B) with ultraviolet rays include a method in which the film is supported by two guide rolls and irradiated between the guide rolls by an ultraviolet irradiation device. Thereby, an ultraviolet-ray can be uniformly irradiated to a film and a uniform ultraviolet curable resin layer can be obtained.

In the step (1), the surface temperature on the irradiation surface side of the film (B) when irradiated with ultraviolet rays is preferably the glass transition temperature (Tg) of the transparent resin constituting the film in order to prevent deformation of the film. The temperature is set to the following temperature, more preferably an arbitrary temperature selected from 40 to 80 ° C. And it is preferable to temperature-control in the variation range of surface temperature +/- 5 degreeC of the irradiation surface of a film (B). A uniform cured film can be formed by the above method. The temperature can be measured by contacting a thermocouple or the like.
The temperature adjustment can be adjusted by the condensing area, irradiation output, or film line speed of the ultraviolet lamp.

    Next, in the step (2) of irradiating the coated surface of the film (B), the film (B) is subjected to a temperature difference of 30 ° C. or less between the coated surface of the film (B) and the opposite surface. Irradiate the coated surface with UV light. By setting the temperature difference to 30 ° C. or less, a more uniform ultraviolet curable resin coating film can be obtained.

  The temperature of the coating surface of the film (B) can be measured by bringing a thermocouple or the like into contact therewith. The temperature of the surface opposite to the coated surface can be determined by measuring the surface temperature of the support. When a temperature difference exceeds 30 degreeC, the adhesiveness of a base film (A) and a cured resin layer will fall. The method for reducing the temperature difference between the coated surface of the film (B) and the surface on the opposite side is not particularly limited.

A method of irradiating the coated surface of the film (B) with ultraviolet rays by bringing a temperature-adjusted support into contact with the surface opposite to the coated surface of the film (B) is preferable.
The support is not limited as long as it has a function capable of adjusting the temperature. Examples of the shape include a flat plate shape and a roll shape. In the present invention, a roll shape is preferable.

  Examples of the function capable of adjusting the temperature include those that allow a liquid heat medium such as steam and hot water to circulate inside, and those that use a heat medium such as an electric heater.

  In the present invention, the temperature of the heat medium for adjusting the temperature of the support is adjusted to a range of 40 ° C. or higher and the glass transition temperature (Tg) of the transparent resin constituting the base film (A), Keep the temperature variation of the heating medium within ± 3 ° C.

The ultraviolet ray to irradiate should just have a wavelength of 100-400 nm normally.
In particular, the ultraviolet lamp is irradiated with ultraviolet rays and infrared rays simultaneously. When the film (B) is irradiated with light with an ultraviolet lamp, the temperature on the irradiated surface side of the film (B) increases. Along with the temperature adjustment on the support side, the temperature distribution in the thickness direction of the film (B) becomes uniform. The atmosphere temperature on the irradiation surface side is preferably 40 to 80 ° C.
It is preferable to provide a glass plate shielding plate 16 in the ultraviolet lamp portion in order to prevent an increase in the ambient temperature of the ultraviolet irradiation surface due to heat generated by the lamp itself.

FIG. 1 is a schematic view showing an example of an apparatus for producing a laminated film.
An apparatus 1 shown in FIG. 1 is an apparatus for continuously winding a long base film: an unwinder 2, an applicator 4 for applying an ultraviolet curable resin, and drying the applied ultraviolet curable resin. The temperature of the drying furnace 7, the ultraviolet lamp 18 for irradiating the surface opposite to the coating surface, the ultraviolet reflector 19, the partition glass plate 20 for shutting off the heat generated from the ultraviolet lamp, and the ultraviolet irradiation device are kept constant. An enclosure 21 for maintaining, an ultraviolet lamp 9 for irradiating the coated surface of the film (B) with ultraviolet rays, a reflector 14 for efficiently irradiating the support with ultraviolet rays, and heat generated from the ultraviolet lamp 9 is cut off. A partition glass plate 16 for carrying out, a back roll 10 as a support, a heat medium tank for adjusting the temperature of the back roll, a circulating pump 15 for sending out a heated heat medium, and a laminated film It can take: winder 13, a guide roll 3,5,6,8,11,12,17 for feeding the film to the respective devices.

The base film is unwound from the unwinder 2 and passes through the applicator 4. In the applicator 4, an ultraviolet curable resin is applied to one side of the base film.
In this embodiment, application is performed by a die coater (not shown). After application, the film passes through a drying oven 7 to dry the ultraviolet curable resin.
The film is supported by the guide roll 17 and the guide roll 8, and an ultraviolet ray is irradiated to the surface opposite to the coating surface by an ultraviolet lamp by an ultraviolet irradiation device installed in the band.

  As the ultraviolet lamp 18, a high-pressure mercury lamp is usually used, and an ultraviolet lamp that emits light centered on 365 nm is preferably used. The output value of the lamp is usually 80 to 300 w, and preferably 100 to 200 w.

The amount of ultraviolet irradiation is preferably 50 to 400 mJ / cm ² , more preferably 100 to 180 mJ / cm ² , and most preferably 130 to 150 mJ / ^second when expressed in terms of the cumulative amount of ultraviolet light with respect to the ultraviolet irradiation object. cm ² .
The integrated light amount is a value determined by the illuminance of the ultraviolet irradiation lamp and the line speed, and is measured with an ultraviolet integrated illuminometer (EYEUV METER UVPF-A1 manufactured by Eye Graphic).

Thereafter, the film is brought into contact with the back roll 10.
The back roll 10 is provided with a heat medium tank with a temperature adjustment function for circulating the heat medium and a circulation pump 15, and is designed so that the temperature of the support 10 can be adjusted with high accuracy. The temperature of the heat medium is adjusted to 40 ° C. or lower and T 3 of the transparent resin constituting the film, and the variation is adjusted within ± 3 ° C.

    The holding angle of the film around the back roll 10 as a support (the angle at which the film is wound around the back roll) is usually 60 to 160 °, preferably 70 to 120 °, and most preferably 80 to 90 °. After the film is brought into contact with the back roll, the ultraviolet lamp 9 irradiates light.

Although the irradiation position of light is not particularly limited, the light is condensed and irradiated in a range of ± 8 °, preferably in a range of ± 5 ° around the bisector of the holding angle.
The distance between the ultraviolet lamp and the support is usually preferably adjusted within 53 ± 5 mm.
The light emitted from this lamp contains infrared rays as well as ultraviolet rays (100 to 400 nm). The film is heated by the infrared rays.
Thus, the reaction efficiency of the ultraviolet curable resin can be improved and a uniform curing reaction can be performed by setting the temperature difference between the coating surface and the opposite side of the coating surface to 30 ° C. or less.

  As the ultraviolet lamp 9, a high-pressure mercury lamp is usually used, and an ultraviolet lamp that emits light centered on 365 nm is preferably used. The output value of the lamp is usually 120 to 340 w, preferably 160 to 250 w.

The amount of ultraviolet irradiation is preferably 100 to 2000 mJ / cm ² , more preferably 200 to 1000 mJ / cm ² , and most preferably 300 to 600 mJ / ^second when expressed in terms of the cumulative amount of ultraviolet light with respect to an ultraviolet irradiation object. cm ² .
The integrated light amount is a value determined by the illuminance of the ultraviolet irradiation lamp and the line speed, and is measured with an ultraviolet integrated illuminometer (EYEUV METER UVPF-A1 manufactured by Eye Graphic).

The laminated film that has been irradiated with the ultraviolet rays is wound around the winder 13.
The line speed of the film is not particularly limited, but is preferably 5 to 30 m / min, more preferably 10 to 25 m / min, and most preferably 10 to 20 m / min.

  The laminated film obtained by the production method of the present invention is, for example, a mobile phone, a digital information terminal, a pager (registered trademark), navigation, an in-vehicle liquid crystal display, a liquid crystal monitor, a light control panel, a display for OA equipment, an AV equipment. It is useful for various liquid crystal display elements such as displays for display, electroluminescence display elements, touch panels, etc., or protective films for polarizing plates.

Next, the present invention will be described in more detail with reference to examples. The present invention is not limited to the following examples.
The test and evaluation in an Example and a comparative example were performed with the following method.

(1) Scratch resistance The film surface was reciprocated 10 times in a state where a load of 0.025 MPa was applied to steel wool # 0000. Subsequently, the surface state was observed visually.
○: Scratches are not recognized.
Δ: Slight scratches are observed.
X: Scratches are observed.

(2) Cross cut test (adhesion test)
A cross-cut tape peeling test is performed in accordance with JIS D0202-1998. 100 grid cuts were made on the cured resin layer of the laminated film using a guide cutter with a gap interval of 1 mm. An adhesive tape (trade name: CT24, manufactured by Nichiban Co., Ltd.) was affixed thereon, pressed with the belly of the finger, and adhered to the surface of the laminated film, and then the adhesive tape was peeled off vertically.
The number of squares that did not peel was counted. The greater the number of cells that did not peel, the better the adhesion.
(3) Pencil hardness It measured with a 500-g load according to JIS-K5700.
(4) Evaluation of coloring property (YI) Based on JIS Z8722, it measures using "spectral color difference meter SE-2000" by Nippon Denshoku Industries Co., Ltd. In the judgment, the value obtained by measuring the film was less than 1.0%, and the value of 1.0% or more was rated as x.
(5) Wrinkle generation Visually determine the film irradiated with ultraviolet rays.
Judgment was made when the film was wrinkled when viewed from the film, and when the wrinkle was not generated at all.

Production Example 1 Production of Base Film 1A Pellets of norbornene-based polymer (ZEONOR 1420R, manufactured by Nippon Zeon Co., Ltd., glass transition temperature: 136 ° C., saturated water absorption: less than 0.01% by weight) are allowed to flow through air. And dried at 110 ° C. for 4 hours using a hot air dryer. Then, a short disk extrusion having a coat hanger type T-die having a lip width of 650 mm with an average surface roughness Ra = 0.04 μm, in which a leaf disk-shaped polymer filter (filtration accuracy of 30 μm) is installed, and the tip of the die lip is chrome-plated Using a machine, the pellets were melt extruded at 260 ° C. to obtain a long base film 1A having a film thickness of 40 μm and a width of 600 mm.
Using a high-frequency transmitter (Corena Generator HV05-2, manufactured by Tamec) on one side of the base film 1A, the corona discharge treatment is performed for 3 seconds, and the surface modification is performed so that the surface tension becomes 0.072 N / m. did.

(Production Example 2) Preparation of UV curable resin agent 1B UV curable urethane acrylate oligomer (purple UV 7640B, number of acryloyl groups: average 6 to 7 per molecule, molecular weight: 1500, manufactured by Nippon Synthetic Chemical Co., Ltd.) 100 parts by weight, 2 -Hydroxy-2-methyl-1-phenylpropan-1-one (Darocur 1173, manufactured by Ciba Specialty Chemicals), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin TPO, manufactured by BASF) ) 2 parts by weight, 20 parts by weight of 2- (2H-benzotriazol-2-yl) -4,6-di-tert-pentylphenol (TINUVIN 328, manufactured by Ciba Specialty Chemicals), 100 parts by weight of methyl isobutyl ketone A UV curable resin agent 1B was prepared by mixing with a homogenizer.

Example 1
The substrate film 1A was attached to the unwinder 2 of the apparatus shown in FIG. 1, and passed through the coating machine 4, the drying furnace 7, and the back roll 10 at a line speed of 15 m / min, and wound up by the winder 13.
In the coating machine, the ultraviolet curable resin agent 1B obtained in Production Example 2 was continuously applied to the surface modification treatment surface of the base film 1A using a die coater. Next, the coating film was dried in a drying furnace 7 having a length of 15 m that was temperature-controlled at 100 ° C.
Next, the film is supported by the two guide rolls 17 and 8, and an ultraviolet lamp 18 installed between the two is used to irradiate the surface opposite to the coating surface with ultraviolet light, and the cumulative amount of ultraviolet light is 250 mJ / cm ² . The output of the ultraviolet lamp, the ultraviolet light collection area, and the line speed were adjusted so that the temperature of the surface opposite to the coated surface was 60 ° C. ± 3 ° C.
Subsequently, the film is brought into contact with the back roll 10, the temperature of the heat medium tank 15 is 45 ° C. ± 3 ° C., and ultraviolet irradiation (integrated light amount 600 mJ / cm ² ) is performed to cure the ultraviolet curable resin agent 1B. A laminated film having a cured resin layer having a thickness of 5 μm was obtained.

Example 2
A laminated film was obtained in the same manner as in Example 1 except that the temperature of the heat medium was adjusted to ± 3 ° C. at 80 ° C.

Example 3
Instead of the base film 1A, a base film 2A made of polyethylene terephthalate (Lumirror T60 # 38, manufactured by Toray Industries, Inc., glass transition temperature: 80 ° C.) having a thickness of 38 μm is used. Corona generator HV05-2 (manufactured by Tamec Co., Ltd.) was used for 3 seconds to perform corona discharge treatment, and surface modification was performed so that the surface tension was 0.072 N / m.
A laminated film was obtained in the same manner as in Example 1 except that this surface-modified film 2A was used.

Example 4
A laminated film was obtained in the same manner as in Example 3, except that the temperature of the heat medium was adjusted to ± 3 ° C. at 75 ° C.

Example 5
Instead of the base film 1A, a base film 3A of 40 μm thick triacetyl cellulose (KC4UX2M, manufactured by Konica Minolta, glass transition temperature: 110 ° C.) is used, and a high-frequency transmitter (Corena Generator HV05 is provided on one side of the film 3A. -2, manufactured by Tamec Co., Ltd.), was subjected to corona discharge treatment for 3 seconds to modify the surface so that the surface tension was 0.072 N / m.
A laminated film was obtained in the same manner as in Example 1 except that this surface-modified film 3A was used.

Example 6
A laminated film was obtained in the same manner as in Example 5 except that the temperature of the heating medium was adjusted to 80 ° C. and ± 3 ° C.

Comparative Example 1
A laminated film was obtained in the same manner as in Example 1 except that the temperature of the heat medium was adjusted to ± 3 ° C. at 25 ° C.

Comparative Example 2
A laminated film was obtained in the same manner as in Example 1 except that the temperature of the heating medium was adjusted to ± 3 ° C. at 140 ° C.

Comparative Example 3
A laminated film was obtained in the same manner as in Example 3 except that the temperature of the heat medium was adjusted to ± 3 ° C. at 25 ° C.

Comparative Example 4
A laminated film was obtained in the same manner as in Example 3 except that the temperature of the heating medium was adjusted to ± 3 ° C. at 90 ° C.

Comparative Example 5
A laminated film was obtained in the same manner as in Example 5 except that the temperature of the heat medium was adjusted to ± 3 ° C. at 25 ° C.

Comparative Example 6
A laminated film was obtained in the same manner as in Example 5 except that the temperature of the heating medium was adjusted to 115C and ± 3C.

Comparative Example 7
A laminated film was obtained in the same manner as in Example 1 except that the surface opposite to the coated surface was not irradiated with ultraviolet light and the temperature of the heat medium was adjusted to ± 3 ° C. at 25 ° C.

Comparative Example 8
A laminated film was obtained in the same manner as in Example 1 except that the surface opposite to the coated surface was not irradiated with ultraviolet light and the temperature of the heat medium was adjusted to ± 3 ° C. at 140 ° C.

Comparative Example 9
A laminated film was obtained in the same manner as in Example 3 except that the surface opposite to the coated surface was not irradiated with ultraviolet rays and the temperature of the heat medium was adjusted to ± 3 ° C. at 25 ° C.

Comparative Example 10
A laminated film was obtained in the same manner as in Example 3, except that the surface opposite to the coated surface was not irradiated with ultraviolet light and the temperature of the heat medium was adjusted to ± 3 ° C. at 90 ° C.

Comparative Example 11
A laminated film was obtained in the same manner as in Example 5 except that the surface opposite to the coated surface was not irradiated with ultraviolet light and the temperature of the heat medium was adjusted to ± 3 ° C. at 25 ° C.

Comparative Example 12
A laminated film was obtained in the same manner as in Example 5, except that the surface opposite to the coated surface was not irradiated with ultraviolet light and the temperature of the heat medium was adjusted to ± 3 ° C. at 115 ° C.

From Table 1, Examples 1 to 6 irradiate ultraviolet light onto the surface opposite to the coated surface with an ultraviolet lamp, and the variation of ± 3 ° C. below the glass transition temperature of the transparent resin is 40 ° C. or higher. The pencil hardness of the laminated film is increased by setting the temperature difference between the coated surface and the opposite surface to 30 ° C. or less.
This shows that the curing is performed efficiently. Also, no peeling occurred in the adhesion. Furthermore, it was proved that scratch resistance was good even when rubbed with steel wool. No discoloration was observed in the YI evaluation. There is no generation of wrinkles.
In Comparative Examples 1 to 6, since the temperature difference between the coated surface and the surface on the opposite side exceeds 30 ° C., the obtained laminated film was not cured by the thermosetting resin, and wrinkles were generated. The base film is deformed.
Furthermore, Comparative Examples 7-12 do not irradiate the surface opposite to the coated surface with ultraviolet rays. Therefore, it turns out that adhesiveness is bad. Bad scratch resistance.

From Table 1, it was confirmed that the production method of the present invention efficiently and uniformly cures the ultraviolet curable resin without deforming the laminated film, has high surface hardness, does not change color, and improves adhesion.

It is an example of the apparatus for manufacturing the laminated | multilayer film of this invention.

Explanation of symbols

  Ultraviolet irradiation device ... 1, device for continuously unwinding a long original film: unwinder ... 2, coating unit ... 4, drying furnace ... 7, ultraviolet lamp ... 9, 18, reflector ... 14, 19, glass plate ... 16, 20, ultraviolet lamp enclosure 21, heat medium tank and delivery pump ... 15, back roll ... 10, take up a long film coated and cured with ultraviolet irradiation resin film: unwinder ... 13, guide rolls 3, 5, 6, 8, 11, 12, 17

Claims (5)

An ultraviolet curable resin is applied to one side of the base film (A) made of a transparent resin to obtain a film (B), and the cumulative amount of ultraviolet rays is 50 to 50% on the side opposite to the coated side of the film (B). Irradiate ultraviolet rays of 400 mJ / cm ² to cure the ultraviolet curable resin,
Next, ultraviolet rays are irradiated on the coated surface of the film (B) under the condition that the temperature difference between the coated surface of the film (B) and the surface on the opposite side is 30 ° C. or less to further cure the ultraviolet curable resin. A method for producing a laminated film. An ultraviolet curable resin is applied to one side of the base film (A) made of a transparent resin to obtain a film (B), and the cumulative amount of ultraviolet rays is 50 to 50% on the side opposite to the coated side of the film (B). Irradiate ultraviolet rays of 400 mJ / cm ² to cure the ultraviolet curable resin,
Next, the surface opposite to the coating surface of the film (B) is brought into contact with a support whose temperature is adjusted with a heat medium under the following conditions, and the coating surface of the film (B) is irradiated with light with an ultraviolet lamp, A method for producing a laminated film in which an ultraviolet curable resin is further cured.
(1) The temperature of the heating medium for adjusting the temperature of the support is 40 ° C. or higher and not higher than the glass transition temperature of the transparent resin.
(2) Temperature variation of the heating medium is within ± 3 ° C.   The said transparent resin is at least 1 type of an alicyclic structure containing polymer resin, a cellulose polymer resin, or a polyester polymer resin, The manufacture of the laminated | multilayer film in any one of Claims 1-2 characterized by the above-mentioned. Method.   The laminated film obtained by the manufacturing method in any one of Claims 1-3. An optical film comprising the laminated film according to claim 4.

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