JP2009084127A - Manufacturing method of ethylene-vinyl acetate copolymer resin film roll for interlayer of laminated glass and ethylene-vinyl acetate copolymer resin film roll for interlayer of laminated glass obtained by the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an EVA film roll for an interlayer of a laminated glass in which the adhesion of EVA film itself and whitening of the EVA film are suppressed even after the passage of a long period of time at ordinary temperatures. <P>SOLUTION: The manufacturing method of an EVA film roll 13 for an interlayer of a laminated glass is characterized by rotationally driving a winding shaft 11, while controlling to set a winding tensile force approximately constant, to roll round an ethylene-vinyl acetate copolymer resin film 10 around the outer circumference of a winding shaft 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a method for producing an ethylene-vinyl acetate copolymer resin film roll used for a laminated glass interlayer film, and in particular, an ethylene-vinyl acetate copolymer resin film roll used for a laminated glass interlayer film and having excellent storage stability. It relates to the manufacturing method.

  Conventionally, a laminated glass having a structure in which a transparent adhesive layer is sandwiched between glass plates as an intermediate film is known. Laminated glass has improved penetration resistance and the like due to the presence of the intermediate film. Accordingly, for example, a laminated glass of an automobile is useful as a security glass because the window cannot be freely opened even if it is broken for the purpose of theft or intrusion. In addition, broken glass fragments remain attached to the intermediate film in response to an impact from the outside, thus preventing scattering.

  Such laminated glass is used as OA-related equipment, office equipment, electrical / electronic equipment, etc. in addition to aircraft and automobile windshields and side glasses, and window glass of buildings. Therefore, the laminated glass is required to have safety such as penetration resistance and prevention of scattering of broken glass, and have high transparency and appearance characteristics.

  As an intermediate film used for laminated glass, a film made of an organic resin such as polyvinyl butyral resin (PVB) or ethylene-vinyl acetate copolymer resin (EVA) is used because of its excellent transparency.

  An intermediate film using such a conventional film made of an organic resin such as EVA is produced by film-forming a composition containing an organic resin and a crosslinking agent by heating and rolling, for example, by extrusion. (Patent Document 1).

  An intermediate film used for laminated glass is generally a product obtained by winding a roll of a predetermined length into a roll after taking a film-forming process and taking into account handling during transport and storage. It becomes. Conventionally, the intermediate film for laminated glass is wound using a surface winding method (surface winding method). This system is a system in which an EVA film is wound around a winding core placed on the surface driving roller by rotationally driving at least one surface driving roller.

  Specifically, as shown in FIG. 7, one of the two surface driving rollers 78 is rotationally driven by a motor (not shown) or the like, so that the core 72 placed on the surface driving roller 78 is moved. In this method, the EVA film 70 is wound around the outer peripheral surface of the core 72 while being rotated in contact with the roll, and an EVA film roll 73 is obtained. Of the arrows indicating the rotation direction, the solid arrow indicates the rotation direction due to the drive rotation, and the broken arrow indicates the rotation direction due to the driven rotation.

  In order to produce laminated glass from such an EVA film roll, laminated glass is produced by drawing an intermediate film from the EVA film roll, sandwiching the intermediate film between two glass substrates, and then thermally fusing it. The

Japanese Patent Laid-Open No. 07-206484

  As an interlayer film for laminated glass, an EVA film is often used among organic resin films because it is excellent in transparency, moisture and heat resistance, and the like.

  Since the organic resin film roll is generally transported or stored in a warehouse, a predetermined time is required until it is applied to the laminated glass. However, conventionally, an EVA film roll wound up in a roll shape is difficult to pull out after several months at room temperature (20 to 30 ° C.), resulting in a decrease in workability, and the EVA film is cloudy. As a result, there are problems such as poor appearance and reduced transparency.

  Therefore, the conventional EVA film roll needs to be transported and stored at a low temperature of 5 to 20 ° C. In addition, when the film is left at room temperature and cannot be used within 3 months, the EVA film wound up in a roll shape becomes difficult to use for laminated glass and may be discarded.

  Therefore, there is a need for an EVA film roll that does not require refrigeration equipment and can be transported at room temperature and stored at room temperature. However, the present condition is that the effective means is not taken with respect to such a subject.

  Therefore, an object of the present invention is to provide an EVA film roll for laminated glass interlayer film in which adhesion between EVA films and white turbidity of the EVA film are suppressed even after a long period of time has passed.

  As a result of various studies on conventional EVA film rolls, the present inventor has found that the above-described problem arises due to the following mechanism.

  That is, in the conventional surface winding method, the surface driving roller on which the winding core is placed is driven to rotate, and the surface driving roller and the winding core are rotated by applying pressure by the weight of the winding core. Rotate the wick. Therefore, if the winding diameter becomes larger than a predetermined value as the EVA film is wound, the weight of the EVA film roll increases, and the winding tension increases due to the influence of the excessive weight. As a result, the EVA film is wound more firmly than necessary. This tends to occur particularly in the EVA film roll, as the EVA film is closer to the core. In the EVA film roll obtained in this way, when a long period of time elapses, the films are more closely adhered to each other and the drawability is lowered, or the deterioration of EVA is promoted over time to cause white turbidity. .

  Therefore, in the conventional surface winding method, it is possible to improve the drawability of the EVA film roll by producing an EVA film using a lubricant, an anti-blocking agent, etc. In such an EVA film roll, Transparency is lowered by a lubricant or an anti-blocking agent, and may not be suitable for use as an interlayer film for laminated glass.

  In the present invention, as a result of focusing on the above-mentioned viewpoint, the winding method is changed, the winding shaft itself is rotationally driven, and the EVA film is wound around the outer periphery of the winding shaft, thereby adjusting the rotational force (torque). It was found that the EVA film can be wound with a constant winding tension. As a result, the EVA film can be softly wound, and an EVA film roll that can be transported at room temperature and stored at room temperature is obtained without requiring refrigeration equipment.

  That is, according to the present invention, the ethylene-vinyl acetate copolymer resin film is wound around the outer periphery of the winding shaft while rotating the winding shaft to control the winding shaft to have a substantially constant winding tension. The above-mentioned problem is solved by a method for producing an ethylene-vinyl acetate copolymer resin film roll for laminated glass interlayer film characterized by the following.

  According to the method of the present invention, it is possible to produce an EVA film roll for laminated glass interlayer film that can be transported at room temperature and stored at room temperature. The EVA film roll thus obtained does not require a large pulling tension of the EVA film and does not cause white turbidity even when a long period of time passes at room temperature. For this reason, refrigeration equipment etc. are unnecessary and it also becomes possible to reduce manufacturing cost.

  An example of the principal part of the EVA film winding apparatus installed in the production line of the EVA film roll for laminated glass interlayer films according to the present invention is shown in FIG. FIG. 1A is a schematic perspective view of an EVA film winding device, and FIG. 1B is a schematic cross-sectional view of the EVA film winding device. This EVA film winding apparatus is installed downstream of the EVA film forming apparatus.

  After the EVA film 10 is formed in a film forming process (not shown), the EVA film 10 is sequentially fed to the winding process at a predetermined speed. In the winding process, the winding shaft 11 is rotated by a rotation driving means (not shown) such as a motor. Is rotated on the outer peripheral surface of the winding shaft 11. The take-up shaft 11 has a hollow cylindrical core 11b such as a paper tube, and a rotation drive shaft 11a inserted into the core 11b. The rotation drive shaft 11a is connected to a rotation drive means (not shown). The

  According to such a method, since there is no contact between the EVA film roll wound around the winding core and the surface driving roller as in the conventional surface winding method, even if the weight of the EVA film roll increases, the winding is not performed. The tension can be controlled to be constant, and the EVA film is not tightly wound. Therefore, in the obtained EVA film roll, strong adhesion between films and deterioration of EVA over time are suppressed, and room temperature transportation and room temperature storage become possible.

  In the method of the present invention, the winding tension of the EVA film is 0.1 to 3.0 kgf / m, preferably 0.5 to 2.5 kgf / m, particularly preferably 1.0 to 2.0 kgf / m. It is good. If the winding tension of the EVA film is less than 0.1 kgf / m, there is a risk of appearance defects such as displacement, and if it exceeds 3.0 kgf / m, wrinkles may occur or hard winding may occur.

  Further, when winding the EVA film, the winding tension may be controlled within the above range from the middle of winding. Specifically, winding is started at a winding tension of 2.0 to 3.0 kgf / m, and after winding the EVA film for laminated glass interlayer film by 0 to 50 m, winding is performed every time 50 m is wound. It is preferable to gradually decrease the tension by 5 to 30%, particularly 10 to 20%. By adjusting the winding tension in this way, it is possible to suppress the roll center portion from being hard-rolled by applying a strong pressure to the roll center portion of the film wound several times. it can.

  In the method of the present invention, the winding speed of the EVA film is 5 to 100 m / min, preferably 10 to 35 m / min, particularly preferably 15 to 30 m / min. If the winding speed of the EVA film is less than 5 m / min, wrinkles may occur or hard winding may occur, and if it exceeds 100 m / min, appearance defects such as misalignment may occur.

  In the method of the present invention, for example, as shown in FIG. 2, the EVA film 20 is wound around a part of the support roll 24 before being wound around the outer periphery of the winding shaft 21, and then wound around the winding shaft 21. Is preferred. Thereby, the vibration of the EVA film can be suppressed and winding can be performed stably.

  Further, as shown in FIG. 3, the winding core 31 is pressed by the contact pressure roll 35, and the winding roll 35 is moved while the winding diameter of the laminated glass intermediate film EVA film 30 is increased. It is preferable that the EVA film 30 for glass interlayer film is wound around the outer periphery of the shaft 31. Thereby, while suppressing the vibration of an EVA film, winding hardness can be adjusted uniformly and winding can be performed more stably.

  It is preferable that the contact pressure roll can change the relative distance from the winding shaft. That is, in order to set the contact pressure on the EVA film roll surface by the contact pressure roll to a predetermined value, the contact pressure roll is preferably separated from the take-up shaft as the diameter of the EVA film roll increases. Moreover, in the method of this invention, you may use combining the support roll and contact pressure roll which were mentioned above. Thereby, winding can be performed stably.

  The contact pressure of the contact pressure roll to the EVA film surface for the laminated glass interlayer film is preferably 5 to 30 N / m, more preferably 10 to 20 N / m. When the contact pressure is less than 5 N / m, there is a risk of deviation when winding the EVA film, and when it exceeds 30 N / m, the EVA film may be hard wound.

  The coefficient of static friction between the surface of the pressure-contacting roll in contact with the EVA film for laminated glass interlayer film and the EVA film for laminated glass interlayer film is preferably 0.1 to 1.0 μs, more preferably 0.1 to 0. .5 μs is recommended. Thereby, generation | occurrence | production of the wrinkle at the time of winding, a damage | wound, etc. can be prevented.

  The static friction coefficient (μs) can be measured using, for example, the measurement method shown in FIG. That is, in an atmosphere of 23 ° C. and 60 RH%, an EVA film 40 (thickness 12 μm, width 100 mm) is held on a pressure roll 45 with a 90 ° holding angle, and a load is applied to one side with a weight 46 of 100 g and the other The push-pull gauge 47 is connected to measure the load, and the static friction coefficient can be obtained by the following equation.

  The film wound up in the method of the present invention is a film formed using an ethylene-vinyl acetate copolymer resin. In the ethylene-vinyl acetate copolymer resin, the content of vinyl acetate units is preferably 20 to 35 parts by mass with respect to 100 parts by mass of the ethylene-vinyl acetate copolymer resin. If the content of vinyl acetate units is less than 20 parts by mass, the transparency of the EVA film may be insufficient, and if it exceeds 35 parts by mass, carboxylic acid, alcohol, amine, etc. are generated over time, and EVA is generated. There is a risk that the EVA film may become clouded.

  The content of vinyl acetate units in the ethylene-vinyl acetate copolymer resin is more preferably 28 to 33 parts by mass, particularly preferably 30 to 33 parts by mass. Thereby, it can be hardened at low temperature and it can be set as the EVA film which is excellent in transparency over a long period of time.

  In the method of the present invention, the length of the EVA film to be wound is preferably long, but if it is too long, wrinkles and misalignment may occur, and the winding hardness may increase, making it impractical. Therefore, the length of the EVA film is preferably about 100 to 1000 m, particularly about 100 to 500 m. It is preferable in view of EVA film roll productivity to wind up the EVA film having such a length.

  The width of the EVA film to be wound is not particularly limited, and may be 0.5 m or more, particularly about 1.0 to 3.0 m.

  The thickness of the EVA film is not particularly limited, and may be determined according to the use of the interlayer film for laminated glass to be used. Therefore, the thickness may be about 0.2 μm to 1.6 mm, particularly about 0.3 μm to 1.3 mm.

  The EVA film may be embossed using known means in order to suppress strong adhesion between the films.

  In the method of the present invention, an EVA film roll is manufactured by winding an EVA film that has undergone a film forming process under the above-described winding conditions. The method of winding the EVA film is not particularly limited as long as the EVA film can be wound around the outer periphery of the winding core connected to the winding shaft by rotating the winding shaft itself. It is particularly preferable to use a method (center winding method). Thereby, the EVA film can be wound with a substantially constant winding tension.

  In the method of the present invention, the EVA film may be formed using a conventionally known method. For example, a composition prepared by mixing EVA and / or EVA monomer or oligomer with various additives such as a crosslinking agent such as an organic peroxide and, if necessary, a crosslinking aid, an adhesion improver, and a plasticizer. Can be manufactured by a method of obtaining a sheet by heating and rolling by ordinary extrusion molding or calendering. The composition containing EVA, organic peroxide, etc. is dissolved in a solvent, and this solution is coated on a suitable support with a suitable coating machine (coater) and dried to form a coating film. A product can also be obtained.

  The formed EVA film is further wound up in a roll shape using the above-mentioned means after performing post-processing as necessary in each step such as a stretching step, a cooling step, and a conveying step.

  An example of a method for producing an EVA film by calendar molding is shown in FIG. A composition (raw material) containing EVA, organic peroxide or the like is put into a kneader 511, and after kneading, the kneaded product 510 is conveyed by a conveyor 512 and supplied to a kneading roll 513. The kneaded material formed into a sheet shape by the kneading roll 513 is conveyed by the conveyor 514, smoothed by the calender roll 515 (first roll 515A, second roll 515B, third roll 515C, fourth roll 515D) and smoothed. The film is removed with take-off roll 516. Thereafter, the surface is embossed by an embossing roll 517, cooled by five cooling rolls 518, and the obtained film 50 is applied to the outer peripheral surface of the winding shaft 51 that is rotationally driven by a rotational driving means (not shown). Wind up.

  When a film is formed by heating and rolling the composition by extrusion molding, calendering or the like, the heating temperature is preferably set to a temperature at which the crosslinking agent does not react or hardly reacts. For example, it is preferably 50 to 90 ° C, particularly 40 to 80 ° C.

  When used for laminated glass, the EVA film obtained as described above is generally crosslinked at 100 to 150 ° C., particularly 125 to 135 ° C., for 10 minutes to 1 hour, particularly 10 to 30 minutes. Such cross-linking may be performed after deaeration in the state of being sandwiched between the transparent substrates and pre-pressing at a temperature of, for example, 80 to 120 ° C. when the laminated glass is manufactured.

  In the production of an EVA film, an organic peroxide or a photopolymerization initiator is preferably used as a crosslinking agent used in the composition. Among these, it is preferable to use an organic peroxide because an EVA film having improved temperature dependency of adhesive strength, transparency, moisture resistance, and penetration resistance can be obtained.

  Any organic peroxide may be used as long as it decomposes at a temperature of 100 ° C. or higher to generate radicals. The organic peroxide is generally selected in consideration of the film formation temperature, the adjustment conditions of the composition, the curing temperature, the heat resistance of the adherend, and the storage stability. In particular, the one having a decomposition temperature of 70 ° C. or more with a half-life of 10 hours is preferable.

  Examples of the organic peroxide include, from the viewpoint of resin processing temperature and storage stability, for example, benzoyl peroxide curing agent, tert-hexyl peroxypivalate, tert-butyl peroxypivalate, 3, 5, 5- Trimethylhexanoyl peroxide, di-n-octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, succinic acid peroxide, 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, tert-hexylperoxy-2-ethylhexa Noate, 4-methylbenzoyl peroxide tert-butylperoxy-2-ethylhexanoate, m-toluoyl + benzoyl peroxide, benzoyl peroxide, 1,1-bis (tert-butylperoxy) -2-methylcyclohexanate, 1,1-bis (Tert-hexylperoxy) -3,3,5-trimethylcyclohexanate, 1,1-bis (tert-hexylperoxy) cyclohexanate, 1,1-bis (tert-butylperoxy) -3 , 3,5-trimethylcyclohexanate, 1,1-bis (tert-butylperoxy) cyclohexanate, 2,2-bis (4,4-di-tert-butylperoxycyclohexyl) propane, 1,1 -Bis (tert-butylperoxy) cyclododecane, tert-hexylperoxy Propyl monocarbonate, tert-butylperoxymaleic acid, tert-butylperoxy-3,3,5-trimethylhexanoate, tert-butylperoxylaurate, 2,5-dimethyl-2,5-di ( Methylbenzoylperoxy) hexane, tert-butylperoxyisopropyl monocarbonate, tert-butylperoxy-2-ethylhexyl monocarbonate, tert-hexylperoxybenzoate, 2,5-di-methyl-2,5-di (benzoyl) Peroxy) hexane, and the like.

  As the benzoyl peroxide-based curing agent, any one can be used as long as it decomposes at a temperature of 70 ° C. or higher to generate radicals. The temperature can be appropriately selected in consideration of the preparation conditions, the film formation temperature, the curing (bonding) temperature, the heat resistance of the adherend, and the storage stability. Usable benzoyl peroxide curing agents include, for example, benzoyl peroxide, 2,5-dimethylhexyl-2,5-bisperoxybenzoate, p-chlorobenzoyl peroxide, m-toluoyl peroxide, 2, Examples include 4-dichlorobenzoyl peroxide and t-butyl peroxybenzoate. The benzoyl peroxide curing agent may be used alone or in combination of two or more.

  In the composition, the content of the organic peroxide is preferably 0.1 to 2 parts by mass, more preferably 0.2 to 1.5 parts by mass with respect to 100 parts by mass of EVA. If the content of the organic peroxide is small, the transparency of the resulting EVA film may be lowered, and if it is increased, the compatibility with the copolymer may be deteriorated.

  Any known photopolymerization initiator used as a crosslinking agent can be used, but a photopolymerization initiator having good storage stability after blending is desirable. Examples of such a photopolymerization initiator include 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, and 2-methyl-1- (4- (methylthio) phenyl). Acetophenones such as 2-morpholinopropane-1, benzoins such as benzyldimethylketal, benzophenones such as benzophenone, 4-phenylbenzophenone and hydroxybenzophenone, thioxanthones such as isopropylthioxanthone and 2-4-diethylthioxanthone, As other special ones, methylphenylglyoxylate can be used. Particularly preferably, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropane-1, Examples include benzophenone. These photopolymerization initiators may contain one or two or more kinds of known and commonly used photopolymerization initiators such as a benzoic acid type such as 4-dimethylaminobenzoic acid or a tertiary amine type, if necessary. Can be mixed and used. Moreover, it can be used individually by 1 type of only a photoinitiator, or 2 or more types of mixture.

  In the composition, the content of the photopolymerization initiator is preferably 0.5 to 5.0 parts by mass with respect to 100 parts by mass of EVA.

  Furthermore, the said composition may contain the crosslinking adjuvant as needed. The crosslinking aid can be added to the composition in order to improve the gel fraction of the ethylene-vinyl acetate copolymer and improve the durability. As a crosslinking aid (compound having a radical polymerizable group as a functional group) used for this purpose, as well-known trifunctional crosslinking aids such as triallyl cyanurate and triallyl isocyanurate, ) Monofunctional or bifunctional crosslinking aids of acrylic esters (eg, NK esters, etc.) can also be mentioned. Of these, triallyl cyanurate and triallyl isocyanurate are preferable, and triallyl isocyanurate is particularly preferable. These crosslinking aids are generally used in an amount of 10 parts by mass or less, preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the ethylene-vinyl acetate copolymer.

  The composition is necessary for improving or adjusting various physical properties of the film (optical properties such as mechanical strength, adhesiveness and transparency, heat resistance, light resistance, crosslinking speed, etc.), especially for improving mechanical strength. Depending on the case, various additives such as a plasticizer and an adhesion improver may be further included.

  The plasticizer is not particularly limited, but polybasic acid esters and polyhydric alcohol esters are generally used. Examples thereof include dioctyl phthalate, dihexyl adipate, triethylene glycol-di-2-ethylbutyrate, butyl sebacate, tetraethylene glycol diheptanoate, and triethylene glycol dipelargonate. One type of plasticizer may be used, or two or more types may be used in combination. The content of the plasticizer is preferably in the range of 5 parts by mass or less with respect to 100 parts by mass of EVA.

  As the adhesion improver, a silane coupling agent can be used. Examples of the silane coupling agent include γ-chloropropylmethoxysilane, vinylethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltri Methoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N- Mention may be made of β- (aminoethyl) -γ-aminopropyltrimethoxysilane. These silane coupling agents may be used alone or in combination of two or more. Moreover, it is preferable that content of the said adhesive improvement agent is 5 mass parts or less with respect to 100 mass parts of EVA.

  Further, the composition may contain an ultraviolet absorber, a light stabilizer and an anti-aging agent.

  The ultraviolet absorber is not particularly limited, but 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2,4-dihydroxybenzophenone, 2,2′-dihydroxy-4- Preferred examples include benzophenone-based ultraviolet absorbers such as methoxybenzophenone and 2-hydroxy-4-n-octoxybenzophenone. In addition, it is preferable that the compounding quantity of the said benzophenone series ultraviolet absorber is 0.01-5 mass parts with respect to 100 mass parts of EVA.

  As the light stabilizer, a light stabilizer called a hindered amine type is preferably used. For example, LA-52, LA-57, LA-62, LA-63LA-63p, LA-67, LA-68 (all of which are stocks) ADEKA), Tinuvin 744, Tinuvin 770, Tinuvin 765, Tinuvin 144, Tinuvin 622LD, CHIMASSORB 944LD (all manufactured by Ciba Specialty Chemicals Co., Ltd.), UV-3034 (manufactured by BF Goodrich) Can do. In addition, the said light stabilizer may be used individually or may be used in combination of 2 or more types, and it is preferable that the compounding quantity is 0.01-5 mass parts with respect to 100 mass parts of EVA.

  Examples of the antioxidant include hindered phenol antioxidants such as N, N′-hexane-1,6-diylbis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionamide]. , Phosphorus heat stabilizers, lactone heat stabilizers, vitamin E heat stabilizers, sulfur heat stabilizers, and the like.

  As described above, the EVA film roll obtained by the method of the present invention does not require a large pulling tension and does not cause white turbidity even when a long period of time passes at room temperature.

  Specifically, the drawing tension of the EVA film when the film is pulled out at a drawing speed of 20 m / min after being left for 720 hours in an environment of a temperature of 23 ° C. and a humidity of 60% RH is 0.1 to 3.0 kgf / EVA film rolls with m, in particular 1.0-2.0 kgf / m are obtained. In the EVA film roll, generally, the pulling tension increases toward the center and the pulling property decreases. However, the EVA film roll of the present invention has a low pulling tension as described above even when left at room temperature. Since it can be kept constant from the start to the end of the drawing, even the EVA film at the center can be easily pulled out and the workability is excellent.

  Further, the EVA film roll has an EVA film haze of 0.5% or less, particularly 0.3% or less after standing for 720 hours in an environment of a temperature of 23 ° C. and a humidity of 60% RH. Even if left alone, high transparency can be maintained over a long period of time.

  The EVA film drawn from the EVA film roll of the present invention is suitably used for laminated glass. That is, as shown in FIG. 6, an EVA film of a predetermined size is used as an intermediate film 62 for laminated glass, and this intermediate film 62 is sandwiched between two transparent substrates 61A and 61B and used as laminated glass.

  In the present invention, the “glass” in the laminated glass means the whole transparent substrate, and therefore the “laminated glass” means one having an intermediate film sandwiched between the transparent substrates.

  Although it does not specifically limit as a transparent substrate used for laminated glass, For example, plastic films other than glass plates, such as a silicate glass, an inorganic glass plate, a non-colored transparent glass plate, may be used. Examples of the plastic film include a polyethylene terephthalate (PET) film, a polyethylene aphthalate (PEN) film, and a polyethylene butyrate film, and a PET film is preferred.

  In the laminated glass according to the present invention, it is preferable that the intermediate film is sandwiched between two transparent substrates and integrated by crosslinking. Such a laminated glass uses the above-described EVA film as an intermediate film, for example, a transparent substrate is attached to both sides of the EVA film, and after deaeration of the sandwich structure, it is pressed under heating. Thus, it is obtained by crosslinking and curing EVA such as EVA contained in the EVA film. The crosslinking conditions are as described above.

  Hereinafter, the present invention will be described with reference to examples. The present invention is not limited by the following examples.

Example 1
The following formulation:
Organic resin: EVA (vinyl acetate content is 32 parts by mass with respect to 100 parts by mass of EVA)
100 parts by mass,
Cross-linking agent: Benzoyl peroxide (NIPPER FF, manufactured by NOF Corporation)
3 parts by mass,
Crosslinking aid: triallyl isocyanurate (TAIC (registered trademark) manufactured by Nippon Kasei Co., Ltd.)
2 parts by mass,
Silane coupling agent: γ-methacryloxypropyltrimethoxysilane (Shin-Etsu Chemical)
Industrial Co., Ltd. KBM-503) 1.0 part by mass,
UV absorber: 2-hydroxy-4-octoxybenzophenone (Sumitomo Chemical Co., Ltd.)
Sumisorb 130) 0.1 parts by mass,
Was supplied to a roll mill and kneaded at 80 ° C. to prepare a composition.

  The above-prepared EVA film-forming composition is calendered at a calender roll temperature of 80 ° C. and a processing speed of 5 m / min, and after standing to cool, an EVA film (width 1 m, thickness 0.4 mm) is continuously produced. Filmed.

This EVA film 200m is a slitter that uses a center winding system (
FN146E manufactured by Nishimura Seisakusho Co., Ltd., with a winding tension of 2.0 kgf / m, a winding speed of 20 m / min, and a contact pressure on the EVA film surface by a contact pressure roll (diameter 100 mm, aluminum alloy) of 20 N / m. As a result, the film was sequentially wound around a winding shaft (a diameter of 100 mm, an aluminum alloy) to obtain an EVA film roll.

(Example 2)
An EVA film roll was obtained in the same manner as in Example 1 except that EVA (content of vinyl acetate was 30 parts by mass with respect to 100 parts by mass of EVA) was used and the winding tension was 1.0 kgf / m.

(Comparative Example 1)
The EVA film 200m produced in the same manner as in Example 1 was taken up using a slitter (SFW-55SA type manufactured by Mayani System Co., Ltd.) employing a surface winding method, and the take-up tension was 20 kgf / m and the take-up speed was 20 m / min. The sample was wound on a winding shaft (diameter 100 mm, aluminum alloy) at a winding contact pressure of 20 N / m to obtain an EVA film roll.

(Comparative Example 2)
An EVA film roll was obtained in the same manner as in Comparative Example 1, except that EVA (vinyl acetate content was 30 parts by mass with respect to 100 parts by mass of EVA) was used and the winding tension was 10 kgf / m.

(Comparative Example 3)
Comparison was made except that 0.1 parts by mass of a phosphate ester lubricant (LTP-2, manufactured by Kawaken Fine Chemical Co., Ltd.) was added to the EVA film forming composition and the winding tension was 1.0 kgf / m. In the same manner as in Example 1, an EVA film roll was obtained.

(Durability evaluation)
The EVA film roll was allowed to stand for 720 hours in an environment of a temperature of 23 ° C. and a humidity of 60% RH, and then the drawing tension and transparency were measured according to the following procedure. The results are summarized in Table 1.

1. Pull-out tension The EVA film was pulled out 100 m from the EVA film roll, and the pull-out tension (kgf / m) when pulling out at a pull-out speed of 5 m / min was measured with a push-pull gauge (DPX-50T manufactured by Imada Co., Ltd.).

2. Transparency The haze value (%) of the EVA film drawn out 100 m from the EVA film roll was measured according to the method of JIS K 7105 (1981). Under the present circumstances, fully automatic direct reading haze computer HGM-2DP (made by Suga Test Instruments Co., Ltd.) was used.

FIG. 1 (A) is a schematic perspective view of an example of an EVA film roll winding device for carrying out the method of the present invention, and FIG. 1 (B) is an EVA film roll for carrying out the method of the present invention. It is a schematic sectional drawing of an example of a winding apparatus. It is a schematic sectional drawing of an example of the winding apparatus of the EVA film roll for enforcing the method of this invention. It is a schematic sectional drawing of an example of the winding apparatus of the EVA film roll for enforcing the method of this invention. An example of a method for measuring the friction coefficient is shown. An example of a production method by calendar molding of the EVA film of the present invention is shown. The schematic sectional drawing of an example of the laminated glass of this invention is shown. It is a schematic sectional drawing of an example of the winding apparatus of the EVA film roll using the conventional surface winding system.

Explanation of symbols

10, 20, 30, 40, 50, 70 EVA film,
11, 21, 31, 51 winding shaft,
11a, 21a, 31a, 51a rotary drive shaft,
11b, 21b, 31b, 51b, 71b winding core,
72 roll core,
13, 23, 33, 53, 73 EVA film roll,
24 support rolls,
35, 45 Pressure roll,
46 weights,
510 kneaded material,
511 kneading machine,
512 conveyor,
513 kneading roll,
514 conveyor,
515 calendar roll,
515A first roll,
515B second roll,
515C third roll,
515D 4th roll,
516 Take off roll,
517 Embossing roll,
518 cooling roll,
61A, 61B transparent substrate,
62 laminated glass interlayer film,
78 surface drive roller,
P Pressing force of the contact pressure roll to the EVA film roll.

Claims (8)

  Laminated glass characterized in that an ethylene-vinyl acetate copolymer resin film is wound around the outer periphery of the winding shaft while controlling the winding shaft to rotate so as to obtain a substantially constant winding tension. A method for producing an ethylene-vinyl acetate copolymer resin film roll for an interlayer film.   The said winding tension is 0.1-3.0 kgf / m, The manufacturing method of the ethylene-vinyl acetate copolymer resin film roll for laminated glass intermediate films of Claim 1 characterized by the above-mentioned.   The ethylene-vinyl acetate copolymer resin film is an ethylene-vinyl acetate copolymer resin having a vinyl acetate unit content of 20 to 35 parts by mass with respect to 100 parts by mass of the ethylene-vinyl acetate copolymer resin. The method for producing an ethylene-vinyl acetate copolymer resin film roll for laminated glass interlayer film according to any one of claims 1 and 2, wherein the film roll is formed by using the method.   The ethylene-acetic acid for laminated glass interlayer film according to claim 3, wherein a content of the vinyl acetate unit is 28 to 33 parts by mass with respect to 100 parts by mass of the ethylene-vinyl acetate copolymer resin. A method for producing a vinyl copolymer resin film roll.   The ethylene-vinyl acetate copolymer for laminated glass interlayer film according to any one of claims 1 to 4, wherein a method of winding the ethylene-vinyl acetate copolymer resin film is a center winding method. Manufacturing method of united resin film roll.   The ethylene-vinyl acetate copolymer resin film roll for laminated glass intermediate films obtained by the method of any one of Claims 1-5.   The draw-out tension of the ethylene-vinyl acetate copolymer resin film when left at 720 hours in an environment of a temperature of 23 ° C. and a humidity of 60% RH and then drawn at a draw speed of 5 to 20 m / min is 0.1. The ethylene-vinyl acetate copolymer resin film roll for laminated glass interlayer film according to claim 6, which is ˜3 kgf / m.   The haze of the ethylene-vinyl acetate copolymer resin film after standing for 720 hours in an environment of a temperature of 23 ° C and a humidity of 60% RH is 0.5% or less. 8. An ethylene-vinyl acetate copolymer resin film roll for laminated glass interlayer film according to 7.

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