JP2007276462A - Manufacturing method of lens film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a lens film excellent in appearance and flexibility and made of a resin by extrusion molding. <P>SOLUTION: The lens film with a thickness of 50-500 μm is manufactured by melting a resin composition, which contains 20-95 pts.wt. of a methacrylic resin and 5-80 pts.wt. of acrylic rubber particles, into a film shape and holding the film like article between a shaping roll and a touch roll to mold the same. The methacrylic resin is preferably composed of a polymer which is obtained by polymerizing 50-100 wt.% of an alkyl methacrylate, 0-50 wt.% of an alkyl acrylate and 0-49 wt.% of a monomer other than these monomers. The acrylic rubber particles are preferably composed of particles containing an elastic polymer obtained by polymerizing 50-99.9 wt.% of the alkyl acrylate, 0-49.9 wt.% of monofunctional monomer other than it and 0.1-10 wt.% of a polyfunctional monomer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a resin lens film by extrusion molding.

  The resin lens sheet is useful as a backlight member of a liquid crystal display device or a screen member of a transmissive display device. In particular, in recent years, a lens associated with a reduction in the thickness of the display device and with an increase in the image quality of the display device. Demand for lens films having a thickness of about 50 to 500 μm is increasing in order to meet the demand for fine pitches. Such a lens film is preferably manufactured by extrusion from the viewpoint of productivity and cost. For example, JP-A-9-304606 (Patent Document 1) contains a polycarbonate resin and a crosslinked acrylic resin. It is disclosed that a prism lens film is manufactured by melt-extruding a resin composition into a film and inserting and molding between nip rolls having a sawtooth shape. Japanese Patent Application Laid-Open No. 2004-287418 (Patent Document 2) discloses that a lenticular lens film can be manufactured by melt-extruding a thermoplastic resin and inserting and molding between a shaping roll and a touch roll. In this case, as the thermoplastic resin, polymethyl methacrylate resin, polycarbonate resin, polystyrene resin, MS resin, AS resin, ABS resin, polypropylene resin, polyethylene resin, polyethylene terephthalate resin, polyvinyl chloride resin, thermoplastic resin are disclosed. It is described that an elastomer, a copolymer thereof and the like are used.

JP-A-9-304606 JP 2004-287418 A

  In the conventional method, when the lens film is released from the forming roll, a peeling pattern (tack mark) is likely to occur on the surface, causing problems in appearance, and the resulting lens film is poor in flexibility and easily cracked. May arise. Therefore, an object of the present invention is to provide a method capable of producing a resin lens film excellent in appearance and flexibility by extrusion molding.

  As a result of intensive studies, the present inventor has found that the above object can be achieved by employing an acrylic resin composition having a predetermined composition as a resin material, and has completed the present invention. That is, the present invention melts a resin composition containing 20 to 95 parts by weight of a methacrylic resin and 5 to 80 parts by weight of acrylic rubber particles and extrudes it into a film shape. The present invention provides a method for producing a lens film having a thickness of 50 to 500 μm by being inserted and molded.

  According to the present invention, a resin lens film excellent in appearance and flexibility can be manufactured by extrusion molding.

  Hereinafter, the present invention will be described in detail. In the present invention, an acrylic resin composition containing a methacrylic resin and acrylic rubber particles in a predetermined ratio is used as a resin material for producing a lens film by extrusion molding.

  The methacrylic resin, which is one of the essential components of this resin composition, is a polymer mainly composed of methacrylic acid ester, and may be a homopolymer of methacrylic acid ester, or 50% by weight or more of methacrylic acid ester. It may be a copolymer with 50% by weight or less of other monomers. Here, as the methacrylic acid ester, an alkyl ester of methacrylic acid is usually used.

  The preferred monomer composition of the methacrylic resin is 50 to 100% by weight of alkyl methacrylate, 0 to 50% by weight of alkyl acrylate, and 0 to 49% by weight of other monomers based on all monomers. More preferably, the alkyl methacrylate is 50 to 99.9% by weight, the alkyl acrylate is 0.1 to 50% by weight, and other monomers are 0 to 49% by weight.

  Here, examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and the like. The alkyl group usually has 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms. It is. Of these, methyl methacrylate is preferably used.

  Examples of alkyl acrylates include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and the like. The alkyl group usually has 1 to 8 carbon atoms.

  The monomer other than alkyl methacrylate and alkyl acrylate may be a monofunctional monomer, that is, a compound having one polymerizable carbon-carbon double bond in the molecule, or a polyfunctional monofunctional monomer. Although it may be a monomer, that is, a compound having at least two polymerizable carbon-carbon double bonds in the molecule, a monofunctional monomer is preferably used. Examples of the monofunctional monomer include aromatic alkenyl compounds such as styrene, α-methylstyrene, and vinyl toluene, and alkenyl cyan compounds such as acrylonitrile and methacrylonitrile. Examples of polyfunctional monomers include polyunsaturated carboxylic acid esters of polyhydric alcohols such as ethylene glycol dimethacrylate, butanediol dimethacrylate, trimethylolpropane triacrylate, allyl acrylate, allyl methacrylate, and cinnamon. Alkenyl esters of unsaturated carboxylic acids such as allyl acids, polyalkenyl esters of polybasic acids such as diallyl phthalate, diallyl maleate, triallyl cyanurate, triallyl isocyanurate, aromatic polyalkenyl compounds such as divinylbenzene, etc. Can be mentioned.

  In addition, as for said alkyl methacrylate, alkyl acrylate, and monomers other than these, respectively, you may use those 2 or more types as needed.

  The methacrylic resin preferably has a glass transition temperature of 40 ° C. or higher, and more preferably 60 ° C. or higher. If this glass transition temperature is too low, the heat resistance of the obtained lens film is lowered, which is not preferable in practice. The glass transition temperature can be appropriately set by adjusting the type of monomer and the ratio thereof.

  The methacrylic resin can be produced by polymerizing the above-described monomer components by a method such as ordinary suspension polymerization, emulsion polymerization, or bulk polymerization. Further, in order to obtain a suitable glass transition temperature or to obtain a viscosity showing a moldability to a suitable lens film, it is preferable to use a chain transfer agent during polymerization. The amount of the chain transfer agent may be appropriately determined depending on the type of monomer and the ratio thereof.

  Acrylic rubber particles, which are another essential component of the resin composition, are particles containing an elastic polymer mainly composed of an acrylate ester as a rubber component, and are particles having a single layer structure made of only this elastic polymer. It may also be a multi-layered particle having this elastic polymer layer. The elastic polymer may be a homopolymer of an acrylate ester or a copolymer of 50% by weight or more of an acrylate ester and 50% by weight or less of other monomers. . Here, as the acrylic ester, an alkyl ester of acrylic acid is usually used.

  The preferable monomer composition of the elastic polymer mainly composed of acrylic acid ester is 50 to 99.9% by weight of alkyl acrylate based on all monomers, and 0 to 49% of other monofunctional monomers. 0.9% by weight and 0.1 to 10% by weight of the polyfunctional monomer.

  Here, the example of alkyl acrylate is the same as the example of alkyl acrylate mentioned above as a monomer component of methacrylic resin, The carbon number of the alkyl group is 1-8 normally, Preferably it is 4-8. is there.

  In addition, the monofunctional monomer other than the alkyl acrylate can be an alkyl methacrylate or other monofunctional monomer, and examples thereof include those of the alkyl methacrylate described above as the monomer component of the methacrylic resin. This is the same as the examples and examples of monofunctional monomers other than alkyl methacrylate and alkyl acrylate.

  Examples of the polyfunctional monomer are the same as the examples of the polyfunctional monomer previously mentioned as the monomer component of the methacrylic resin, and among them, alkenyl esters of unsaturated carboxylic acids and polybasic acids. Polyalkenyl esters are preferably used.

  In addition, as for said alkyl acrylate, the other monofunctional monomer, and a polyfunctional monomer, you may use those 2 or more types as needed, respectively.

  When the acrylic rubber particles having a multilayer structure are used, a preferable example is one having a polymer layer mainly composed of methacrylic acid ester outside the elastic polymer layer mainly composed of acrylate ester. That is, there can be mentioned those having at least a two-layer structure in which an elastic polymer layer mainly composed of an acrylate ester is used as an inner layer and a polymer layer mainly composed of a methacrylic acid ester is used as an outer layer. Here, as the methacrylic acid ester which is a monomer component of the polymer in the outer layer, alkyl methacrylate is usually used. The outer layer polymer is usually formed at a ratio of 10 to 400 parts by weight, preferably 20 to 200 parts by weight with respect to 100 parts by weight of the inner layer elastic polymer. By setting the polymer of the outer layer to 10 parts by weight or more with respect to 100 parts by weight of the elastic polymer of the inner layer, the elastic polymer is hardly aggregated and the transparency is improved.

  The preferable monomer composition of the polymer of the outer layer is 50 to 100% by weight of alkyl methacrylate, 0 to 50% by weight of alkyl acrylate, and other monomers 0 to 49 based on all monomers. % By weight.

  Here, the example of alkyl methacrylate is the same as the example of alkyl methacrylate previously mentioned as a monomer component of a methacryl resin, The carbon number of the alkyl group is 1-8 normally, Preferably it is 1-4. is there. Of these, methyl methacrylate is preferably used.

  Moreover, the example of alkyl acrylate is the same as that of the example of alkyl acrylate mentioned previously as a monomer component of a methacryl resin, and the carbon number of the alkyl group is 1-8 normally.

  Monomers other than alkyl methacrylate and alkyl acrylate may be monofunctional monomers or polyfunctional monomers, but monofunctional monomers are preferably used. Examples of this monofunctional monomer are the same as the examples of monofunctional monomers other than the alkyl methacrylate and alkyl acrylate mentioned above as the monomer component of the methacrylic resin, Examples of the monomer are the same as those of the polyfunctional monomer mentioned above as the monomer component of the methacrylic resin.

  In addition, as for said alkyl methacrylate, alkyl acrylate, and monomers other than these, respectively, you may use those 2 or more types as needed.

  Further, as a preferred example of the acrylic rubber particles having a multilayer structure, a polymer layer mainly composed of a methacrylic acid ester is further provided inside the elastic polymer layer mainly composed of an acrylate ester which is the inner layer of the two-layer structure. That is, a polymer layer mainly composed of methacrylic acid ester as an inner layer, an elastic polymer layer mainly composed of acrylate ester as an intermediate layer, and a polymer mainly composed of the above methacrylic acid ester There can also be mentioned at least a three-layer structure with the outer layer as the outer layer. Here, as a methacrylic acid ester which is a monomer component of the polymer of the inner layer, alkyl methacrylate is usually used. The polymer of the inner layer is usually formed at a ratio of 10 to 400 parts by weight, preferably 20 to 200 parts by weight, with respect to 100 parts by weight of the elastic polymer of the intermediate layer.

  A preferable monomer composition of the polymer of the inner layer is 70 to 100% by weight of alkyl methacrylate and 0 to 30% by weight of other monomers based on all monomers.

  Here, the example of alkyl methacrylate is the same as the example of alkyl methacrylate previously mentioned as a monomer component of a methacryl resin, The carbon number of the alkyl group is 1-8 normally, Preferably it is 1-4. is there. Of these, methyl methacrylate is preferably used.

  The monomer other than alkyl methacrylate may be an alkyl acrylate or other monofunctional monomer, or may be a polyfunctional monomer. And examples of this monofunctional monomer are the same as the examples of alkyl acrylates mentioned above as monomer components of methacrylic resins, and examples of monofunctional monomers other than alkyl methacrylates and alkyl acrylates. In addition, examples of the polyfunctional monomer are the same as the examples of the polyfunctional monomer previously mentioned as the monomer component of the methacrylic resin.

  In addition, as for said alkyl methacrylate and monomers other than these, respectively, you may use those 2 or more types as needed.

  Such acrylic rubber particles having a three-layer structure are disclosed in, for example, Japanese Patent Publication No. 55-27576 (US Pat. No. 3,793,402). In particular, the one described in Example 3 of the publication is one of the preferred compositions.

  The acrylic rubber particles can be produced by polymerizing the monomer component of the elastic polymer mainly composed of the above-described acrylic ester by an emulsion polymerization method or the like in at least one stage reaction. At this time, as described above, when a polymer layer mainly composed of methacrylic acid ester is formed outside the elastic polymer layer, the monomer component of the outer layer polymer is added to the elastic polymer layer. What is necessary is just to graft to the said elastic polymer by making it superpose | polymerize by reaction of at least 1 step | paragraph by emulsion polymerization method etc. in presence of a polymer. Further, as described above, when a polymer layer mainly composed of methacrylic acid ester is formed inside the elastic polymer layer, first, the monomer component of the polymer in the inner layer is Polymerization is carried out by at least one stage reaction by emulsion polymerization or the like, and then the monomer component of the elastic polymer is polymerized by at least one stage reaction by emulsion polymerization or the like in the presence of the resulting polymer. In the presence of the resulting elastic polymer, the monomer component of the outer layer polymer is polymerized in an at least one-step reaction by an emulsion polymerization method or the like. To be grafted to the elastic polymer. When the polymerization of each layer is performed in two or more stages, it is sufficient that the monomer composition as a whole is in the above range, not the monomer composition of each stage.

  Regarding the particle diameter of the acrylic rubber particles, the average particle diameter of the elastic polymer layer mainly composed of acrylic acid ester in the rubber particles is preferably 0.05 to 0.4 μm, and more preferably 0. It is 06-0.3 micrometer, More preferably, it is 0.1-0.25 micrometer. If the average particle diameter is too large, the transparency of the resulting lens film is lowered, which is not preferable. On the other hand, if the average particle size is too small, the impact resistance of the resulting lens film is lowered and becomes brittle, and the productivity is also lowered.

  The average particle size is determined by mixing acrylic rubber particles with methacrylic resin to form a film, dyeing the elastic polymer layer with ruthenium oxide in the cross section, and observing with an electron microscope. It can be determined from the diameter. That is, when acrylic rubber particles are mixed with methacrylic resin and the cross section is dyed with ruthenium oxide, the methacrylic resin of the parent phase is not dyed, and a polymer mainly composed of methacrylic acid ester is formed outside the elastic polymer layer. If present, the outer layer polymer is not dyed, and only the elastic polymer layer is dyed. Thus, the particle diameter is obtained from the diameter of the portion dyed in this manner and observed in an approximately circular shape with an electron microscope. be able to. When a polymer mainly composed of methacrylic acid ester is present inside the elastic polymer layer, the inner layer polymer is not dyed, and the outer elastic polymer layer is dyed in a two-layer structure. In this case, the outer diameter of the two-layer structure, that is, the outer diameter of the elastic polymer layer may be considered.

  The blending ratio of the methacrylic resin and the acrylic rubber particles is 20 to 95 parts by weight of the methacrylic resin and 5 to 80 parts by weight of the acrylic rubber particles based on the total of 100 parts by weight of both. When the ratio of the methacrylic resin is too small and the ratio of the acrylic rubber particles is too large, the appearance of the obtained lens film is deteriorated. On the other hand, when the proportion of the methacrylic resin is too large and the proportion of the acrylic rubber particles is too small, the appearance of the obtained lens film is deteriorated and the flexibility is lowered as described above.

  The amount of the elastic polymer mainly composed of acrylic ester in the acrylic rubber particles is preferably 5 to 35 parts by weight based on the total of 100 parts by weight of the methacrylic resin and the acrylic rubber particles. More preferred are parts by weight. If the amount of the elastic polymer is 5 parts by weight or more per 100 parts by weight of the total of methacrylic resin and acrylic rubber particles, the film forming property can be improved without the lens film becoming brittle. On the other hand, if the amount of the elastic polymer per 35 parts by weight of the total of methacrylic resin and acrylic rubber particles is 35 parts by weight or less, the transparency and surface hardness of the lens film can be improved.

  In the present invention, the resin composition containing the methacrylic resin and the acrylic rubber particles described above is used as the resin material for extrusion molding. However, this resin composition may contain other components such as an ultraviolet absorber as necessary. Ordinary additives such as organic dyes, inorganic dyes, pigments, antioxidants, antistatic agents, and surfactants may be contained. Further, this resin composition preferably has a melt flow rate (MFR), which is an indicator of fluidity, of 0.5 to 5 at 220 ° C., more preferably 0.6 to 3.5. . If the melt flow rate is too low, it becomes difficult to form a lens film. On the other hand, if the melt flow rate is too high, the stability of the resin reservoir (bank) formed between the shaping roll and the touch roll is deteriorated, and the shaping state of the lens shape tends to be nonuniform.

  The lens film is produced by melting the resin composition in an extruder, extruding it into a film shape through a T-shaped die, etc., and inserting the film-like material between a rotating shaping roll and a touch roll. It is performed by sandwiching between rolls and shaping.

  The shaping roll is a roll for imparting a desired lens shape to the film-like material, and has a lens shape on the surface, that is, a reverse shape of the lens shape. As the shaping roll, a metal roll is usually used, and a roll whose surface is subjected to a plating treatment such as copper plating is preferable. Moreover, about the shape of a shaping roll, a general straight roll, a crowning roll, etc. are employable.

  The touch roll is a roll for pressing the film-like material against the shaping roll, and the surface is usually a smooth surface (mirror surface), but may have a shape-giving function such as a lens mold if necessary. Good. If a touch roll having a smooth surface is used, a single-sided lens film can be produced, and if a touch roll having a lens mold on the surface is used, a double-sided lens film can be produced. A rubber roll or a metal roll is usually used as the touch roll, but a metal roll is preferable. Moreover, about the shape of a touch roll, a general straight roll, a crowning roll, etc. are employable like a shaping roll.

  When the film-like material is inserted between both rolls, the linear pressure applied to the film-like material is preferably 200 kN / cm or more, and 220 to 350 kN / cm from the viewpoint of formability. More preferred. As a mechanism for pressing the touch roll in order to apply linear pressure in this way, a hydraulic cylinder, a motor, or the like can be used.

  Further, the temperature of the shaping roll during molding is preferably higher than Tg-30 (° C.) when the glass transition temperature of the resin composition is expressed as Tg (° C.), and lower than Tg. Is preferred. That is, when the temperature of the shaping roll is expressed as Tr (° C.), it is preferable that Tg−30 <Tr <Tg, and therefore 0 <Tg−Tr <30. If the temperature of the shaping roll is too low, the resin composition is likely to solidify before the lens shape is completely molded, so that the moldability or uniformity thereof tends to decrease. On the other hand, if the temperature of the shaping roll is too high, a peeling pattern (tack mark) is likely to occur on the surface when the lens film is released from the shaping roll. Note that the temperature of the touch roll is preferably slightly lower than the temperature of the shaping roll. The roll temperature can be adjusted by using a roll capable of passing a heat medium therein and adjusting the temperature of the heat medium.

  The lens film thus obtained has a thickness of 50 to 500 μm, preferably 50 to 300 μm, and more preferably 100 to 200 μm. A lens film that is too thick does not follow the preference of thinning the display device, and the rigidity increases, so handling and secondary workability deteriorate, making it difficult to handle, and the unit price per unit area is low. Because it increases, it becomes economically disadvantageous. On the other hand, when the lens film is too thin, it is difficult to give the lens shape by extrusion due to mechanical limitations. The thickness of the lens film can be adjusted by adjusting the film forming speed, the thickness of the T-shaped die outlet, the gap between the rolls, and the like. In addition, the thickness of a lens film here is the maximum thickness, and if it is a single-sided lens film, it is the distance from the surface in contact with the convex vertex of the lens surface to the opposite surface, and if it is a double-sided lens film The distance from the surface in contact with the convex vertex of one lens surface to the surface in contact with the convex vertex of the opposite lens surface. Further, it is preferable to adjust the thickness of the discharge port of the T-shaped die so that the thickness of the film-like material is about 2 to 10 times the thickness of the desired lens film.

  Examples of the lens shape formed on the lens film include a prism lens, a lenticular lens, and a Fresnel lens, but the method of the present invention is particularly suitably used for manufacturing a film having a prism lens shape. . In this case, it is preferable that the pitch of the lens shape is 200 μm or less and the height is 100 μm or less from the viewpoint of the fine pitch of the lens that is required with the recent improvement in image quality of display devices.

  Examples of the present invention will be described below, but the present invention is not limited thereto. In the examples, “%” and “part” representing the content or amount used are based on weight unless otherwise specified.

  As the methacrylic resin, thermoplastic polymer pellets having a glass transition temperature of 104 ° C. obtained by bulk polymerization of a monomer composed of 97.8% methyl methacrylate and 2.2% methyl acrylate were used. This glass transition temperature is an extrapolated glass transition start temperature obtained at a heating rate of 10 ° C./min by differential scanning calorimetry (DSC) according to JIS K 7121, and the glass transition temperature of the resin composition described later is the same. It is.

  As the acrylic rubber particles (A), the innermost layer is a hard polymer obtained by polymerization of a monomer composed of 93.8% methyl methacrylate, 6% methyl acrylate, and 0.2% allyl methacrylate, The intermediate layer is an elastic polymer obtained by polymerization of a monomer composed of 81% butyl acrylate, 17% styrene and 2% allyl methacrylate, and the outermost layer is 94% methyl methacrylate and 6% methyl acrylate. The weight ratio of the innermost layer / intermediate layer / outermost layer is 35/45/20, and the average particle diameter of the elastic polymer layer of the intermediate layer A rubber particle having a spherical three-layer structure by an emulsion polymerization method having a particle size of 0.22 μm was used.

  The acrylic rubber particles (B) have basically the same composition as the acrylic rubber particles (A), but by changing the polymerization conditions, the average particle diameter of the elastic polymer layer of the intermediate layer becomes 0.14 μm. Rubber particles having a spherical three-layer structure were used.

  In addition, the average particle diameter of the elastic polymer layer of the intermediate layer in the acrylic rubber particles (A) and (B) was measured by the following method.

(Measurement of average particle diameter of elastic polymer layer)
Acrylic rubber particles are mixed with the above methacrylic resin to form a film, and the resulting film is cut into an appropriate size, and the slice is immersed in a 0.5% aqueous ruthenium tetroxide solution at room temperature for 15 hours. The elastic polymer layer was dyed. Further, the sample was cut to a thickness of about 80 nm using a microtome, and then photographed with a transmission electron microscope. After randomly selecting 100 dyed elastic polymer layers from this photograph and calculating the particle diameter of each, the number average value was taken as the average particle diameter.

Examples 1 to 4, Comparative Examples 1 and 2

  The above methacrylic resin pellets and acrylic rubber particles (A) or (B) were mixed at a ratio shown in Table 1 with a super mixer, and melt-kneaded with a twin-screw extruder to obtain resin composition pellets. . Table 1 shows the glass transition temperature Tg of this resin composition. Next, this pellet was melted with a 65 mmφ single screw extruder manufactured by Toshiba Machine Co., Ltd., and extruded through a T-type die having a set temperature of 275 ° C., and the resulting film-like product was pitched to the surface at a pitch of 100 μm and a height of 50 μm (vertex) The metal forming roll having a prism lens mold with an angle of 90 ° was sandwiched between a metal touch roll having a smooth surface and molded. At that time, the temperature Tr of the shaping roll was set to the temperature shown in Table 1, and the linear pressure applied to the film-like material was 330 kN / cm. Table 1 shows the difference (Tg−Tr) between the glass transition temperature Tg of the resin composition and the temperature Tr of the shaping roll. Thus, a prism lens film having a thickness of 0.175 mm was manufactured, and the following evaluation was performed. The results are shown in Table 1.

[Flexibility test]
According to JIS K 5400-1990 “General test method for paints”, “8. Test method for resistance of paint film”, “8.1 Bend resistance”, the flex resistance of the lens film is evaluated and the test piece breaks. The test piece was evaluated as “Good” when the flexibility was good, and “X” when the test piece was broken and lacked flexibility.

〔appearance〕
The surface state of the lens film was confirmed by visual observation, and the case where no tack mark was seen was marked with ◯, and the case where a tack mark was seen was marked with x.

Claims (8)

  A resin composition containing 20 to 95 parts by weight of methacrylic resin and 5 to 80 parts by weight of acrylic rubber particles is melted and extruded into a film, and the film is inserted between a shaping roll and a touch roll to be molded. A method for producing a lens film having a thickness of 50 to 500 μm.   The methacrylic resin is a polymer obtained by polymerizing 50 to 100% by weight of alkyl methacrylate, 0 to 50% by weight of alkyl acrylate, and 0 to 49% by weight of other monomers. 2. The production method according to 1.   Acrylic rubber particles in a proportion of 50 to 99.9% by weight of alkyl acrylate, 0 to 49.9% by weight of other monofunctional monomers, and 0.1 to 10% by weight of polyfunctional monomers The production method according to claim 1, wherein the particles are particles containing an elastic polymer obtained by polymerization.   Acrylic rubber particles have a ratio of 50 to 100% by weight of alkyl methacrylate, 0 to 50% by weight of alkyl acrylate, and 0 to 49% by weight of other monomers on the outside of the elastic polymer layer. 4. The production method according to claim 3, wherein the particles are multi-layered particles having a polymer layer obtained by polymerization.   A layer of polymer in which acrylic rubber particles are polymerized in a proportion of 70 to 100% by weight of alkyl methacrylate and 0 to 30% by weight of other monomers inside the layer of the elastic copolymer. The production method according to claim 4, wherein the particles have a multi-layer structure.   The manufacturing method according to claim 1, wherein a linear pressure applied to the film-like material inserted between the shaping roll and the touch roll is 200 kN / cm or more.   The temperature of the shaping roll is a temperature higher than Tg-30 (° C) and lower than Tg (° C) when the glass transition temperature of the resin composition is expressed as Tg (° C). The manufacturing method of crab.   The manufacturing method according to claim 1, wherein the lens film is a prism lens film.