WO2018199172A1 - Protective film - Google Patents

Protective film Download PDF

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Publication number
WO2018199172A1
WO2018199172A1 PCT/JP2018/016834 JP2018016834W WO2018199172A1 WO 2018199172 A1 WO2018199172 A1 WO 2018199172A1 JP 2018016834 W JP2018016834 W JP 2018016834W WO 2018199172 A1 WO2018199172 A1 WO 2018199172A1
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WO
WIPO (PCT)
Prior art keywords
protective film
layer
resin substrate
styrene
polyolefin
Prior art date
Application number
PCT/JP2018/016834
Other languages
French (fr)
Japanese (ja)
Inventor
和房 小野寺
Original Assignee
住友ベークライト株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 住友ベークライト株式会社 filed Critical 住友ベークライト株式会社
Priority to JP2018535189A priority Critical patent/JPWO2018199172A1/en
Publication of WO2018199172A1 publication Critical patent/WO2018199172A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C53/00—Shaping by bending, folding, twisting, straightening or flattening; Apparatus therefor
    • B29C53/02—Bending or folding
    • B29C53/04—Bending or folding of plates or sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/28—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J123/00—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J153/00—Adhesives based on block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers
    • C09J153/02—Vinyl aromatic monomers and conjugated dienes
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]

Definitions

  • the present invention relates to a protective film that is used by being attached to a resin substrate when the resin substrate is subjected to hot bending under heating.
  • a lens for sunglasses provided with a resin substrate having a structure in which both sides of a polarizer are covered with a coating layer made of polycarbonate resin, polyamide resin or cellulose resin.
  • a lens for sunglasses is manufactured as follows, for example. First, a protective film is affixed on both surfaces of the said resin substrate which makes flat form by planar view. In this state, the resin substrate is punched into a predetermined shape such as a circular shape in plan view. Thereafter, the resin substrate is subjected to heat bending under heating. Then, the protective film is peeled off from the resin substrate subjected to the thermal bending. Thereafter, a polycarbonate layer is injection molded on the concave surface of the resin substrate. Thereby, the lens for sunglasses is manufactured.
  • This protective film includes, for example, a base material and an adhesive layer. Specifically, a protective film having a structure in which a base material mainly composed of a polyolefin-based resin is attached to the resin substrate via an adhesive layer mainly composed of polyethylene, ethylene-propylene copolymer, or the like. It has been proposed (see, for example, Patent Document 1).
  • the protective film having such a structure can be attached to the resin substrate without being peeled off at the time of punching the resin substrate and at the time of thermal bending (particularly at the time of thermal bending), but has the following problems. there were. That is, the protective film having the above-described configuration tends to increase the adhesion strength to the resin substrate after the thermal bending process. As a result, when the protective film is peeled off from the resin substrate, adhesive residue derived from the adhesive layer is generated on the resin substrate, which causes a problem of reducing the yield of the manufactured lens for sunglasses.
  • Such a problem occurs not only in the above-mentioned sunglasses lens but also in a resin substrate such as a lens provided in goggles and a visor provided in a helmet.
  • An object of the present invention is to be able to be stuck to a resin substrate without being peeled off during the heat bending process of the resin substrate, and when the protective film is peeled off from the resin substrate after the heat bending process, the adhesive residue derived from the adhesive layer
  • An object of the present invention is to provide a protective film capable of accurately suppressing or preventing the occurrence of selenium on a resin substrate.
  • the protective film is used by being attached to the resin substrate, A base material layer, and an adhesive layer that is located between the base material layer and the resin substrate and adheres to the resin substrate;
  • the said adhesion layer contains polyolefin and the styrene block elastomer whose content of styrene is 25 wt% or less,
  • the protective film characterized by the above-mentioned.
  • the polyolefin has a melt flow rate of 0.5 g / 10 min or more and 10.0 g / 10 min or less measured under the conditions of a heating temperature of 230 ° C. and a load of 2.16 kgf in accordance with JIS K7210.
  • the protective film according to any one of 1) to (3).
  • a coating layer composed of a single layer or a laminate having at least one of a polycarbonate resin layer, a polyamide resin layer, and a cellulose resin layer on both surfaces, one surface, or the other surface of the resin substrate.
  • the protective film according to any one of the above (1) to (6).
  • the adhesive residue can be adhered to the resin substrate without being peeled off during the heat bending process of the resin substrate, and when the protective film is peeled off from the resin substrate after the heat bending process, Can be accurately suppressed or prevented from occurring in the resin substrate. Therefore, when the resin substrate is applied to, for example, a resin substrate included in a sunglasses lens, the sunglasses lens can be manufactured with a high yield.
  • FIG. 1 is a schematic diagram for explaining a method of manufacturing a lens for sunglasses using a protective film.
  • FIG. 2 is a longitudinal sectional view showing a preferred embodiment of the protective film of the present invention.
  • the protective film of the present invention is a protective film that is used by being attached to the resin substrate when the resin substrate is subjected to a heat bending process under heating.
  • the protective film has a base material layer, and an adhesive layer that is located between the base material layer and the resin substrate and adheres to the resin substrate, and the adhesive layer contains a polyolefin and a content of styrene. Containing 25 wt% or less of a styrene block elastomer.
  • the adhesive layer included in the protective film By making the adhesive layer included in the protective film into such a configuration, it can be attached to the resin substrate without being peeled off during the heat bending process of the resin substrate, and the protective film is peeled off from the resin substrate after the heat bending process. It is possible to accurately suppress or prevent the adhesive residue derived from the adhesive layer from being generated on the resin substrate. Therefore, when the resin substrate is applied to, for example, a resin substrate included in a sunglasses lens, the sunglasses lens can be manufactured with a high yield.
  • FIG. 1 is a schematic diagram for explaining a method of manufacturing a lens for sunglasses using a protective film.
  • the upper side of FIG. 1 is referred to as “upper” and the lower side is referred to as “lower”.
  • a flat resin substrate 21 is prepared, and a protective film 10 (masking tape) is applied to both surfaces of the resin substrate 21, so that the protective film 10 is applied to both surfaces of the resin substrate 21.
  • a laminated body 100 is obtained (see FIG. 1A).
  • a resin substrate 21 including a polarizer 23 and a coating layer 24 is prepared.
  • the polarizer 23 functions as an optical element that extracts linearly polarized light having a polarization plane in a predetermined direction from unpolarized natural light.
  • the covering layer 24 covers both surfaces of the polarizer 23.
  • the coating layer 24 is constituted by a single layer or a laminate having at least one of a polycarbonate resin layer, a polyamide resin layer, and a cellulose resin layer such as triacetyl cellulose. .
  • the coating layer 24 is formed on both surfaces (both surfaces) of the polarizer 23, as well as the upper surface (one surface) and the lower surface (the other surface). It may be formed either.
  • the prepared laminate 100 that is, the resin substrate 21 is punched in the thickness direction with the protective film 10 applied to both surfaces of the resin substrate 21. .
  • the laminated body 100 is made into circular shape by planar view.
  • the laminated body 100 having a circular shape is subjected to hot bending under heating.
  • This hot bending process is usually performed by press forming or vacuum forming.
  • the resin substrate 21 includes the coating layer 24, and the coating layer 24 includes at least one of a polycarbonate resin layer, a polyamide resin layer, and a cellulose resin layer. Consists of the body.
  • the heating temperature (molding temperature) of the laminated body 100 (resin substrate 21) during the hot bending process is preferably about 110 ° C. or higher and 150 ° C. or lower in consideration of the melting or softening temperature of the coating layer 24.
  • it is set to about 140 ° C. or higher and 150 ° C. or lower.
  • the protective film 10 is peeled off from the heat-bent resin substrate 21, that is, the laminate 100, and the concave surface of the resin substrate 21 is made of polycarbonate resin.
  • the polycarbonate layer 30 is injection molded.
  • a polyamide layer made of a polyamide resin may be formed on the concave surface of the resin substrate 21 instead of the polycarbonate layer 30.
  • the lens 200 for sunglasses including the resin substrate 21 subjected to the thermal bending is manufactured.
  • the protective film of the present invention By applying the protective film of the present invention to the method for manufacturing a lens for sunglasses as described above, the resin substrate 21 in the step [2] and the step [3] without peeling off the protective film 10 from the resin substrate 21. Punching and thermal bending can be carried out, and the peeling of the protective film 10 from the resin substrate 21 in the step [4] can be accurately suppressed or the occurrence of adhesive residue derived from the adhesive layer 11 on the resin substrate 21 can be accurately suppressed or It can be implemented with prevention.
  • the protective film of the present invention will be described in detail.
  • the adhesion layer 11 should just contain polyolefin and the styrene block elastomer whose content of styrene is 25 wt% or less, and the structure of the base material layer 15 is not specifically limited.
  • the base material layer 15 is comprised with the laminated body of the 1st layer 16 and the 2nd layer 17 is demonstrated to an example.
  • FIG. 2 is a longitudinal sectional view showing a preferred embodiment of the protective film of the present invention.
  • the upper side of FIG. 2 is referred to as “upper” and the lower side is referred to as “lower”.
  • the protective film 10 includes a base material layer 15 and an adhesive layer 11 that is located between the base material layer 15 and the resin substrate 21 and adheres (bonds) to the resin substrate 21.
  • the base material layer 15 includes a first layer 16 located on the opposite side of the adhesive layer 11, that is, the mold side, and the adhesive layer 11 side, that is, the resin substrate 21. And a second layer 17 located on the side.
  • Adhesion layer 11 The adhesive layer 11 is positioned (intervened) between the base material layer 15 and the resin substrate 21 and adheres to the resin substrate 21.
  • the adhesive layer 11 has a function of bonding the base material layer 15 to the resin substrate 21.
  • the adhesive layer 11 contains polyolefin and a styrene block elastomer having a styrene content of 25 wt% or less.
  • the resin substrate 21 is peeled off when the protective film 10 is peeled from the resin substrate 21 in the step [4]. It is possible to accurately suppress or prevent the adhesive layer 11 from remaining on the surface. That is, it is possible to accurately suppress or prevent the occurrence of adhesive residue derived from the adhesive layer 11 in the resin substrate 21.
  • the styrene block elastomer (styrene elastomer having a styrene block) is not particularly limited, but is preferably a styrene-olefin-styrene block copolymer elastomer.
  • a styrene-olefin-styrene block copolymer is used as the styrene block elastomer containing styrene as a monomer component, and the styrene content is 25 wt% or less.
  • the resin in the step [4] is used. Generation of adhesive residue on the substrate 21 can be more accurately suppressed or prevented.
  • styrene-olefin-styrene block copolymer examples include styrene-isobutylene-styrene block copolymer (SIBS), styrene-ethylene-butylene-styrene block copolymer (SEBS), and styrene-butadiene-styrene block.
  • SIBS styrene-isobutylene-styrene block copolymer
  • SEBS styrene-ethylene-butylene-styrene block copolymer
  • SEBS styrene-ethylene-butylene-styrene block copolymer
  • the styrene content in the elastomer can be set to 25 wt% or less relatively easily, and the above-described effects can be obtained more reliably. it can.
  • the styrene content in the elastomer may be 25 wt% or less, but is preferably 10 wt% or more and 18 wt% or less.
  • the content of the elastomer in the adhesive layer 11 is not particularly limited, but is preferably set to 20 wt% or more and 80 wt% or less, more preferably 30 wt% or more and 60 wt% or less. Thereby, the effect acquired by making the adhesion layer 11 contain the styrene block elastomer whose content of styrene is 25 wt% or less can be exhibited more notably.
  • the adhesive layer 11 contains a polyolefin in addition to the styrene block elastomer having a styrene content of 25 wt% or less as described above.
  • the adhesive layer 11 contains polyolefin
  • the resin substrate 21 is punched and thermally bent in the step [2] and the step [3] without peeling off the protective film 10 from the resin substrate 21. While being able to do, peeling of the protective film 10 from the resin substrate 21 in the said process [4] can be implemented comparatively easily.
  • the melting point of the polyolefin is preferably 150 ° C. or higher, more preferably 155 ° C. or higher and 160 ° C. or lower.
  • the easy peelability of the protective film 10 from the resin substrate 21 can be expressed using peel strength.
  • the protective film 10 is attached to the coating layer 24 to obtain a laminate. Thereafter, the peel strength T 1 between the coating layer 24 and the protective film 10 measured in accordance with JIS C-6481: 1996 after storing the laminate at a temperature of 50 ° C. for 12 hours, and The peel strength T 2 between the coating layer 24 and the protective film 10 measured in accordance with JIS C-6481: 1996 after storing the laminate at a temperature of 150 ° C.
  • the step [2 ] And punching and thermal bending of the resin substrate 21 in the step [3] can be performed without peeling off the protective film 10 from the resin substrate 21, and the thermal history due to the thermal bending in the step [3] can be obtained. Even if the protective film 10 has passed, the protective film 10 can be reliably peeled from the resin substrate 21 in the step [4].
  • the polyolefin is not particularly limited, and for example, a polypropylene homopolymer (homopolymer), a polyethylene homopolymer, a propylene-ethylene block copolymer having an EPR phase (rubber phase), an ethylene-vinyl acetate block Examples thereof include a copolymer, an ethylene-ethyl acrylate block copolymer, an ethylene-methyl methacrylate block copolymer, and the like, and one or more of them can be used in combination. Among these, a polypropylene homopolymer (homopolymer) is preferable.
  • a polypropylene homopolymer can be obtained at a relatively low cost, and a polypropylene homopolymer having a melting point of 150 ° C. or higher can also be easily obtained. Moreover, if it is a homopolymer of a polypropylene, transparency can be provided to the adhesion layer 11. Therefore, when the base material layer 15 has transparency similarly, the protective film 10 can be provided with transparency. Therefore, when the protective film 10 is stuck on the resin substrate 21 in the step [1], it can be visually confirmed whether dust such as dust is interposed between the protective film 10 and the resin substrate 21. Therefore, it can prevent reliably that the laminated body 100 in which refuse exists after the said process [2] transfers. As a result, the yield of the obtained sunglasses lens 200 is improved.
  • the polyolefin has a melt flow rate (MFR) of 0.5 g / 10 min or more and 10.0 g / 10 min or less measured under the conditions of a heating temperature of 230 ° C. and a load of 2.16 kgf in accordance with JIS K7210. It is preferably 1.0 g / 10 min or more and 5.0 g / 10 min or less, more preferably 2.0 g / 10 min or more and 3.5 g / 10 min or less.
  • the melting point of each layer constituting the protective film 10 including the adhesive layer 11 is the melting point of each constituent material included in each layer (peak temperature by DSC measurement). The value determined by the sum of the ratios contained is taken as the melting point.
  • the average thickness of the adhesive layer 11 is preferably 5 ⁇ m or more and 40 ⁇ m or less, and more preferably 10 ⁇ m or more and 20 ⁇ m or less. Thereby, the function as the adhesion layer 11 mentioned above can be exhibited reliably.
  • Base material layer 15 is bonded to the resin substrate 21 (covering layer 24) through the adhesive layer 11.
  • the base material layer 15 functions as a functional layer (protective layer) that protects (masks) the resin substrate 21 during the punching and thermal bending of the resin substrate 21 in the step [2] and the step [3]. is there.
  • the base material layer 15 may have any configuration as long as it exhibits such a function, and may be a single layer or a laminate.
  • the base material layer 15 includes a first layer 16 located on the opposite side of the adhesive layer 11, that is, the mold side, and the adhesive layer 11 side, that is, the resin substrate 21. The case where it comprises with the laminated body which has the 2nd layer 17 located in the side is demonstrated.
  • first layer 16 is located on the opposite side of the adhesive layer 11, that is, on the mold side during the thermal bending in the step [3], and functions as the outermost layer for protecting the resin substrate 21.
  • the first layer 16 maintains excellent detachability from the mold after the thermal bending in the step [3], that is, the first layer 16 does not adhere to the mold (mold).
  • the melting point of the first layer 16 is preferably 150 ° C. or higher, more preferably about 155 ° C. or higher and 165 ° C. or lower.
  • the heating temperature of the coating layer 24 (resin substrate 21) during the thermal bending in the step [3] is preferably set to about 110 ° C. or more and 150 ° C. or less. Therefore, by setting the melting point of the first layer 16 as described above, it is possible to reliably prevent the first layer 16 from being melted or softened during the thermal bending in the step [3]. Therefore, the laminate 100 can be reliably detached from the mold after the thermal bending in the step [3].
  • Such a constituent material of the first layer 16 is preferably a thermoplastic resin having a melting point of 150 ° C. or higher, and more preferably a polyolefin having a melting point of 150 ° C. or higher.
  • fusing point of the 1st layer 16 can be easily set to 150 degreeC or more.
  • the 2nd layer 17 mentioned later is also set as the structure containing polyolefin, the adhesiveness of the base material layer 15 (1st layer 16 and 2nd layer 17) and the adhesion layer 11 can be improved. Since it can do, it can suppress or prevent exactly that peeling arises in each layer with which the protective film 10 is provided.
  • fusing point of 150 degreeC or more is mentioned among the polyolefin contained in the adhesion layer 11 mentioned above, for example.
  • the average thickness of the first layer 16 is preferably 10 ⁇ m or more and 50 ⁇ m or less, and more preferably 15 ⁇ m or more and 35 ⁇ m or less. Thereby, the function as the 1st layer 16 mentioned above can be exhibited reliably.
  • the second layer 17 is located on the adhesive layer 11 side, that is, on the resin substrate 21 side, and functions as an intermediate layer located between the adhesive layer 11 and the first layer 16.
  • the second layer 17 is in a melted / softened state during the thermal bending in the step [3], and the first layer 16 protrudes at the edge of the curved surface of the laminated body 100 by the thermal bending of the laminated body 100.
  • the base layer 15 is provided for the purpose of functioning as an intermediate layer for forming the gripping white. For this reason, it is preferable that melting
  • the heating temperature of the coating layer 24 (resin substrate 21) during the thermal bending in the step [3] is preferably set to about 110 ° C. or more and 150 ° C. or less.
  • the second layer 17 can be surely brought into a molten or softened state during the thermal bending in the step [3]. Accordingly, in the step [3], the second layer 17 functions as an intermediate layer in a molten or softened state, and the first layer 16 is displaced with respect to the surface direction of the resin substrate 21. Can be. As a result, grabbing scissors by the first layer 16 are formed at the edge of the stacked body 100. Therefore, since peeling of the protective film 10 in the said process [4] can be implemented by grasping and holding this white, this peeling can be performed easily.
  • the length of the gripping white and L 1, a diameter in plan view after it has been bent heat and L 2 laminate 100 forms a circular shape in plan view by the step [3], the step [3] (L 1 / L 2 ) ⁇ 100 is preferably 0.1% or more and 1% or less, and preferably 0.2% or more, when the curvature radius R of the laminated body 100 heat-bent by is set to 8.5 cm. More preferably, it is 0.5% or less.
  • the protective film 10 in the step [4] can be reliably peeled off using the gripping white formed in the step [3].
  • Such a constituent material of the second layer 17 is preferably a thermoplastic resin having a melting point of less than 120 ° C, and more preferably a polyolefin having a melting point of less than 120 ° C.
  • fusing point of the 2nd layer 17 can be easily set to less than 120 degreeC.
  • the first layer 16 described above also includes a polyolefin, the adhesion between the base material layer 15 (the first layer 16 and the second layer 17) and the adhesive layer 11 can be improved. Since it can do, it can suppress or prevent exactly that peeling arises in each layer with which the protective film 10 is provided.
  • the polyolefin having a melting point of less than 120 ° C. includes a polyolefin having a melting point of less than 120 ° C. among the polyolefins contained in the adhesive layer 11 described above. Examples thereof include a polyethylene homopolymer having a melting point of less than 120 ° C., an ⁇ -olefin / polyethylene copolymer, an ⁇ -olefin / polypropylene copolymer, and the like.
  • the average thickness of the second layer 17 is preferably 10 ⁇ m or more and 60 ⁇ m or less, and more preferably 15 ⁇ m or more and 30 ⁇ m or less. Thereby, the function as the 2nd layer 17 mentioned above can be exhibited reliably.
  • each of the adhesive layer 11 and the base material layer 15 (the first layer 16 and the second layer 17) included in the protective film 10 described above includes an antioxidant, a light Various additives such as a stabilizer and an antistatic agent may be contained. Further, an intermediate layer containing the above-described additives and the like may be formed between these layers.
  • the protective film 10 described above may be manufactured by any method, for example, it can be manufactured by using a coextrusion method.
  • the protective film 10 is manufactured by supplying the obtained laminated body to the sheet
  • each layer which comprises a protective film can be substituted with the layer of the arbitrary structures which can exhibit the same function.
  • the protective film of the present invention is used by being attached to a resin substrate when the resin substrate included in the lens for sunglasses is hot-bent has been described.
  • the protective film of the present invention can be applied to thermal bending of a resin substrate included in such a lens for sunglasses, and is also used when, for example, a resin substrate such as a lens provided in goggles or a visor provided in a helmet is thermally bent. be able to.
  • an adhesive layer forming material is prepared by kneading SEBS having a styrene content of 12 wt% and random polypropylene having a melting point of 145 ° C. so that the SEBS content is 50 wt%. (Resin composition) was prepared.
  • Example 2A to Example 7A Comparative Example 1A to Comparative Example 3A
  • Example 2A to Example 7A and Comparative Example 1A to Comparative Example 3A were the same as Example 1A, except that the average thickness of the adhesive layer in each laminate was changed as shown in Table 1. A protective film was obtained.
  • A The peel strength is 0.10 N / 25 mm or more and 1.5 N / 25 mm or less.
  • B The peel strength is 0.05 N / 25 mm or more and less than 0.10 N / mm, or 1.5 N / 25 mm or more and 3.0 N / 25 mm or less.
  • C The peel strength is less than 0.05 N / 25 mm or more than 3.0 N / 25 mm.
  • the laminate was thermally bent by vacuum forming.
  • the protective film was peeled from the polycarbonate substrate, and the presence or absence of the adhesive residue in a polycarbonate substrate was observed after that. And the observation result of the presence or absence of adhesive residue was evaluated based on the following evaluation criteria.
  • a styrene-olefin-styrene block copolymer having a styrene content of 25 wt% or less was used as the elastomer in the adhesive layer of the protective film.
  • the protective film in each Example in the laminate of the polycarbonate substrate and the protective film after heat bending, the protective film can be easily peeled from the polycarbonate substrate without any adhesive residue remaining on the polycarbonate substrate. Became clear.
  • the protective film in each comparative example an elastomer not containing styrene or a styrene-olefin-styrene block copolymer having a styrene content exceeding 25 wt% was used as the elastomer contained in the adhesive layer. For this reason, in the protective film in each comparative example, when the protective film was peeled off from the polycarbonate substrate, a clear adhesive residue was observed on the polycarbonate substrate.
  • Example 2B to Example 13B In the step [1B], the type of polyolefin used in place of the 158 ° C. homopolypropylene (Nobrene FS2011DG2), the content of the elastomer contained in the adhesive layer forming material prepared in the step [1B], in the step [3B] Protective films of Examples 2B to 13B were obtained in the same manner as in Example 1B except that the average thickness of the adhesive layer in the laminate to be formed was changed as shown in Table 2.
  • the obtained laminate was stored under the conditions of a temperature of 50 ° C. and a time of 12 hours, and then the peel strength T 1 between the polycarbonate substrate and the protective film was measured according to JIS C-6481: 1996.
  • a resin substrate (Sumitomo Bakelite, manufactured by Sumitomo Bakelite Co., Ltd.) having a polarizer held between two polycarbonate substrates (polycarbonate layer), respectively. “P1352”) was prepared.
  • Each protective film was bonded to both surfaces of each resin substrate using a roll under the condition of a load of 0.5 kg / cm 2 , and a laminate was obtained by attaching the protective film.
  • the obtained laminate was stored under the conditions of a temperature of 150 ° C. and a time of 5 minutes, and then the peel strength T 2 between the polycarbonate substrate and the protective film was measured according to JIS C-6481: 1996.
  • the adhesive residue can be adhered to the resin substrate without being peeled off during the heat bending process of the resin substrate, and when the protective film is peeled off from the resin substrate after the heat bending process, It is possible to provide a protective film capable of accurately suppressing or preventing the occurrence of selenium on the resin substrate. Therefore, the present invention has industrial applicability.

Abstract

This protective film 10 is used adhered on to a resin substrate 21, when thermal-bending the resin substrate 21 under heat. The protective film 10 has a base material layer and an adhesive layer positioned between this base material layer and the resin substrate 21 and adhering to the resin substrate 21. The adhesive layer contains polyolefin and a styrene block elastomer having a styrene content of no more than 25 wt%.

Description

保護フィルムProtective film
　本発明は、樹脂基板に対して、加熱下で熱曲げ加工を施す際に、樹脂基板に貼付して用いられる保護フィルムに関する。 The present invention relates to a protective film that is used by being attached to a resin substrate when the resin substrate is subjected to hot bending under heating.
　ポリカーボネート樹脂、ポリアミド樹脂またはセルロース樹脂で構成される被覆層で偏光子の両面を被覆した構成をなす樹脂基板を備えるサングラス用レンズがある。このようなサングラス用レンズは、例えば、次のようにして製造される。まず、平面視で平板状をなす前記樹脂基板の両面に保護フィルムを貼付する。この状態で、平面視で円形状等の所定の形状に、前記樹脂基板を打ち抜く。その後、この樹脂基板に対して、加熱下で熱曲げ加工を施す。そして、熱曲げがなされた樹脂基板から、保護フィルムを剥離させる。その後に、この樹脂基板の凹面にポリカーボネート層を射出成形する。これにより、サングラス用レンズが製造される。 There is a lens for sunglasses provided with a resin substrate having a structure in which both sides of a polarizer are covered with a coating layer made of polycarbonate resin, polyamide resin or cellulose resin. Such a lens for sunglasses is manufactured as follows, for example. First, a protective film is affixed on both surfaces of the said resin substrate which makes flat form by planar view. In this state, the resin substrate is punched into a predetermined shape such as a circular shape in plan view. Thereafter, the resin substrate is subjected to heat bending under heating. Then, the protective film is peeled off from the resin substrate subjected to the thermal bending. Thereafter, a polycarbonate layer is injection molded on the concave surface of the resin substrate. Thereby, the lens for sunglasses is manufactured.
　この保護フィルムは、例えば、基材と、粘着層とを備えている。具体的には、ポリオレフィン系樹脂を主材料とする基材を、ポリエチレン、エチレン－プロピレン共重合体等を主材料とする粘着層を介して、前記樹脂基板に対して貼付する構成の保護フィルムが提案されている（例えば、特許文献１参照。）。 This protective film includes, for example, a base material and an adhesive layer. Specifically, a protective film having a structure in which a base material mainly composed of a polyolefin-based resin is attached to the resin substrate via an adhesive layer mainly composed of polyethylene, ethylene-propylene copolymer, or the like. It has been proposed (see, for example, Patent Document 1).
　しかしながら、かかる構成の保護フィルムでは、樹脂基板の打ち抜き時、および、熱曲げ加工時（特に、熱曲げ加工時）に剥離させることなく樹脂基板に貼付させることができるものの、次のような問題があった。すなわち、上記構成の保護フィルムは、熱曲げ加工の後に、樹脂基板に対する密着強度が高くなる傾向を示す。その結果、樹脂基板からの保護フィルムの剥離の際に粘着層に由来する糊残りが樹脂基板に生じるため、製造されるサングラス用レンズの歩留まりの低下を招くと言う問題があった。 However, the protective film having such a structure can be attached to the resin substrate without being peeled off at the time of punching the resin substrate and at the time of thermal bending (particularly at the time of thermal bending), but has the following problems. there were. That is, the protective film having the above-described configuration tends to increase the adhesion strength to the resin substrate after the thermal bending process. As a result, when the protective film is peeled off from the resin substrate, adhesive residue derived from the adhesive layer is generated on the resin substrate, which causes a problem of reducing the yield of the manufactured lens for sunglasses.
　なお、このような問題は、上述したサングラス用レンズばかりでなく、ゴーグルが備えるレンズ、ヘルメットが備えるバイザー等の樹脂基板についても同様に生じている。 Such a problem occurs not only in the above-mentioned sunglasses lens but also in a resin substrate such as a lens provided in goggles and a visor provided in a helmet.
特開２００３－１４５６１６号公報JP 2003-145616 A
　本発明の目的は、樹脂基板の熱曲げ加工時に剥離させることなく樹脂基板に貼付させることができるとともに、熱曲げ加工の後に樹脂基板から保護フィルムを剥離させる際に、粘着層に由来する糊残りが樹脂基板に生じるのを的確に抑制または防止し得る保護フィルムを提供することにある。 It is an object of the present invention to be able to be stuck to a resin substrate without being peeled off during the heat bending process of the resin substrate, and when the protective film is peeled off from the resin substrate after the heat bending process, the adhesive residue derived from the adhesive layer An object of the present invention is to provide a protective film capable of accurately suppressing or preventing the occurrence of selenium on a resin substrate.
　このような目的は、下記（１）～（８）に記載の本発明により達成される。
　（１）　樹脂基板に対して、加熱下で熱曲げ加工を施す際に、前記樹脂基板に貼付して用いられる保護フィルムであって、
　基材層と、該基材層と前記樹脂基板との間に位置し、前記樹脂基板に粘着する粘着層とを有し、
　前記粘着層は、ポリオレフィンと、スチレンの含有量が２５ｗｔ％以下のスチレンブロックエラストマーとを含有することを特徴とする保護フィルム。 Such an object is achieved by the present invention described in the following (1) to (8).
(1) When the resin substrate is subjected to a heat bending process under heating, the protective film is used by being attached to the resin substrate,
A base material layer, and an adhesive layer that is located between the base material layer and the resin substrate and adheres to the resin substrate;
The said adhesion layer contains polyolefin and the styrene block elastomer whose content of styrene is 25 wt% or less, The protective film characterized by the above-mentioned.
　（２）　前記スチレンブロックエラストマーは、スチレン－オレフィン－スチレンブロック共重合体を含む上記（１）に記載の保護フィルム。 (2) The protective film according to (1), wherein the styrene block elastomer includes a styrene-olefin-styrene block copolymer.
　（３）　前記ポリオレフィンは、その融点が１５０℃以上である上記（１）または（２）に記載の保護フィルム。 (3) The protective film according to (1) or (2), wherein the polyolefin has a melting point of 150 ° C. or higher.
　（４）　前記ポリオレフィンは、そのＪＩＳ  Ｋ７２１０に準拠して加熱温度２３０℃、荷重２．１６ｋｇｆの条件下において測定されるメルトフローレートが０．５ｇ／１０ｍｉｎ以上１０．０ｇ／１０ｍｉｎ以下である上記（１）ないし（３）のいずれかに記載の保護フィルム。 (4) The polyolefin has a melt flow rate of 0.5 g / 10 min or more and 10.0 g / 10 min or less measured under the conditions of a heating temperature of 230 ° C. and a load of 2.16 kgf in accordance with JIS K7210. The protective film according to any one of 1) to (3).
　（５）　前記ポリオレフィンは、ポリプロピレンのホモポリマーを含む上記（１）ないし（４）のいずれかに記載の保護フィルム。 (5) The protective film according to any one of (1) to (4), wherein the polyolefin includes a homopolymer of polypropylene.
　（６）　前記樹脂基板の両面に貼付される上記（１）ないし（５）のいずれかに記載の保護フィルム。 (6) The protective film according to any one of (1) to (5), which is attached to both surfaces of the resin substrate.
　（７）　前記樹脂基板の両面、一方の面または他方の面に、ポリカーボネート樹脂層、ポリアミド樹脂層およびセルロース樹脂層のうちの少なくとも１層を有する単層体または積層体で構成される被覆層が設けられる上記（１）ないし（６）のいずれかに記載の保護フィルム。 (7) A coating layer composed of a single layer or a laminate having at least one of a polycarbonate resin layer, a polyamide resin layer, and a cellulose resin layer on both surfaces, one surface, or the other surface of the resin substrate. The protective film according to any one of the above (1) to (6).
　（８）　前記樹脂基板は、プレス成形または真空成形により、前記熱曲げ加工される上記（１）ないし（７）のいずれかに記載の保護フィルム。 (8) The protective film according to any one of (1) to (7), wherein the resin substrate is subjected to the heat bending process by press molding or vacuum molding.
　本発明によれば、樹脂基板の熱曲げ加工時に剥離させることなく樹脂基板に貼付させることができるとともに、熱曲げ加工の後に樹脂基板から保護フィルムを剥離させる際に、粘着層に由来する糊残りが樹脂基板に生じるのを的確に抑制または防止することができる。そのため、樹脂基板を、例えば、サングラス用レンズが備える樹脂基板に適用した場合には、サングラス用レンズを歩留まりよく製造することができる。 According to the present invention, the adhesive residue can be adhered to the resin substrate without being peeled off during the heat bending process of the resin substrate, and when the protective film is peeled off from the resin substrate after the heat bending process, Can be accurately suppressed or prevented from occurring in the resin substrate. Therefore, when the resin substrate is applied to, for example, a resin substrate included in a sunglasses lens, the sunglasses lens can be manufactured with a high yield.
図１は、保護フィルムを用いたサングラス用レンズの製造方法を説明するための模式図である。FIG. 1 is a schematic diagram for explaining a method of manufacturing a lens for sunglasses using a protective film. 図２は、本発明の保護フィルムの好適実施形態を示す縦断面図である。FIG. 2 is a longitudinal sectional view showing a preferred embodiment of the protective film of the present invention.
　以下、本発明の保護フィルムを添付図面に示す好適な実施形態に基づいて詳細に説明する。 Hereinafter, the protective film of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
　本発明の保護フィルムは、樹脂基板に対して、加熱下で熱曲げ加工を施す際に、前記樹脂基板に貼付して用いられる保護フィルムである。かかる保護フィルムは、基材層と、該基材層と前記樹脂基板との間に位置し、前記樹脂基板に粘着する粘着層とを有し、前記粘着層は、ポリオレフィンと、スチレンの含有量が２５ｗｔ％以下のスチレンブロックエラストマーとを含有することを特徴とする。 The protective film of the present invention is a protective film that is used by being attached to the resin substrate when the resin substrate is subjected to a heat bending process under heating. The protective film has a base material layer, and an adhesive layer that is located between the base material layer and the resin substrate and adheres to the resin substrate, and the adhesive layer contains a polyolefin and a content of styrene. Containing 25 wt% or less of a styrene block elastomer.
　保護フィルムが備える粘着層を、かかる構成のものとすることで、樹脂基板の熱曲げ加工時に剥離させることなく樹脂基板に貼付させることができるとともに、熱曲げ加工の後に樹脂基板から保護フィルムを剥離させる際に、粘着層に由来する糊残りが樹脂基板に生じるのを的確に抑制または防止することができる。そのため、樹脂基板を、例えば、サングラス用レンズが備える樹脂基板に適用した場合には、サングラス用レンズを歩留まりよく製造することができる。 By making the adhesive layer included in the protective film into such a configuration, it can be attached to the resin substrate without being peeled off during the heat bending process of the resin substrate, and the protective film is peeled off from the resin substrate after the heat bending process. It is possible to accurately suppress or prevent the adhesive residue derived from the adhesive layer from being generated on the resin substrate. Therefore, when the resin substrate is applied to, for example, a resin substrate included in a sunglasses lens, the sunglasses lens can be manufactured with a high yield.
　以下、本発明の保護フィルムを説明するのに先立って、本発明の保護フィルムを用いて製造される、サングラス用レンズの製造方法について説明する。 Hereinafter, prior to describing the protective film of the present invention, a method for manufacturing a lens for sunglasses manufactured using the protective film of the present invention will be described.
　＜サングラス用レンズの製造方法＞
　図１は、保護フィルムを用いたサングラス用レンズの製造方法を説明するための模式図である。なお、以下では、説明の都合上、図１の上側を「上」、下側を「下」と言う。 <Production method of lenses for sunglasses>
FIG. 1 is a schematic diagram for explaining a method of manufacturing a lens for sunglasses using a protective film. Hereinafter, for convenience of explanation, the upper side of FIG. 1 is referred to as “upper” and the lower side is referred to as “lower”.
　以下、サングラス用レンズの製造方法の各工程を詳述する。
　［１］まず、平板状をなす樹脂基板２１を用意し、この樹脂基板２１の両面に、保護フィルム１０（マスキングテープ）を貼付することで、樹脂基板２１の両面に保護フィルム１０が貼付された積層体１００を得る（図１（ａ）参照）。 Hereinafter, each process of the manufacturing method of the lens for sunglasses is explained in full detail.
[1] First, a flat resin substrate 21 is prepared, and a protective film 10 (masking tape) is applied to both surfaces of the resin substrate 21, so that the protective film 10 is applied to both surfaces of the resin substrate 21. A laminated body 100 is obtained (see FIG. 1A).
　なお、本実施形態では、偏光子２３と、被覆層２４とを備える樹脂基板２１が用意される。偏光子２３は、偏光していない自然光から、所定の一方向に偏光面をもつ直線偏光を取出す光学素子として機能する。被覆層２４は、偏光子２３の両面を被覆している。なお、この樹脂基板２１において、被覆層２４は、ポリカーボネート樹脂層、ポリアミド樹脂層、および、トリアセチルセルロースのようなセルロース樹脂層のうちの少なくとも１層を有する単層体または積層体で構成される。さらに、被覆層２４は、図１（ａ）のように、偏光子２３の両面（双方の面）に形成される場合の他、上面（一方の面）および下面（他方の面）のうちのいずれかに形成されるものであってもよい。 In this embodiment, a resin substrate 21 including a polarizer 23 and a coating layer 24 is prepared. The polarizer 23 functions as an optical element that extracts linearly polarized light having a polarization plane in a predetermined direction from unpolarized natural light. The covering layer 24 covers both surfaces of the polarizer 23. In this resin substrate 21, the coating layer 24 is constituted by a single layer or a laminate having at least one of a polycarbonate resin layer, a polyamide resin layer, and a cellulose resin layer such as triacetyl cellulose. . Further, as shown in FIG. 1A, the coating layer 24 is formed on both surfaces (both surfaces) of the polarizer 23, as well as the upper surface (one surface) and the lower surface (the other surface). It may be formed either.
　［２］次に、図１（ｂ）に示すように、用意した積層体１００を、すなわち、樹脂基板２１の両面に保護フィルム１０を貼付した状態で樹脂基板２１を、その厚さ方向に打ち抜く。これにより、積層体１００を平面視で円形状とする。 [2] Next, as shown in FIG. 1 (b), the prepared laminate 100, that is, the resin substrate 21 is punched in the thickness direction with the protective film 10 applied to both surfaces of the resin substrate 21. . Thereby, the laminated body 100 is made into circular shape by planar view.
　［３］次に、図１（ｃ）に示すように、円形状とされた積層体１００に対して、加熱下で熱曲げ加工を施す。
　この熱曲げ加工は、通常、プレス成形または真空成形により実施される。 [3] Next, as shown in FIG. 1C, the laminated body 100 having a circular shape is subjected to hot bending under heating.
This hot bending process is usually performed by press forming or vacuum forming.
　前述の通り、本実施形態では、樹脂基板２１が被覆層２４を備え、被覆層２４が、ポリカーボネート樹脂層、ポリアミド樹脂層、および、セルロース樹脂層のうちの少なくとも１層を有する単層体または積層体で構成されている。このため、熱曲げ加工の際の積層体１００（樹脂基板２１）の加熱温度（成形温度）は、被覆層２４の溶融または軟化温度を考慮して、好ましくは１１０℃以上１５０℃以下程度、より好ましくは１４０℃以上１５０℃以下程度に設定される。加熱温度をかかる範囲内に設定することにより、樹脂基板２１の変質・劣化を防止しつつ、樹脂基板２１を軟化または溶融状態として、樹脂基板２１を確実に熱曲げすることができる。 As described above, in this embodiment, the resin substrate 21 includes the coating layer 24, and the coating layer 24 includes at least one of a polycarbonate resin layer, a polyamide resin layer, and a cellulose resin layer. Consists of the body. For this reason, the heating temperature (molding temperature) of the laminated body 100 (resin substrate 21) during the hot bending process is preferably about 110 ° C. or higher and 150 ° C. or lower in consideration of the melting or softening temperature of the coating layer 24. Preferably, it is set to about 140 ° C. or higher and 150 ° C. or lower. By setting the heating temperature within such a range, the resin substrate 21 can be reliably heat-bended while the resin substrate 21 is softened or melted while preventing the resin substrate 21 from being altered or deteriorated.
　［４］次に、図１（ｄ）に示すように、熱曲げがなされた樹脂基板２１すなわち積層体１００から、保護フィルム１０を剥離させた後、この樹脂基板２１の凹面にポリカーボネート樹脂で構成されるポリカーボネート層３０を射出成形する。なお、樹脂基板２１の凹面には、ポリカーボネート層３０に代えて、例えば、ポリアミド樹脂で構成されるポリアミド層を形成してもよい。 [4] Next, as shown in FIG. 1 (d), the protective film 10 is peeled off from the heat-bent resin substrate 21, that is, the laminate 100, and the concave surface of the resin substrate 21 is made of polycarbonate resin. The polycarbonate layer 30 is injection molded. For example, a polyamide layer made of a polyamide resin may be formed on the concave surface of the resin substrate 21 instead of the polycarbonate layer 30.
　これにより、熱曲げがなされた樹脂基板２１を備えるサングラス用レンズ２００が製造される。 Thereby, the lens 200 for sunglasses including the resin substrate 21 subjected to the thermal bending is manufactured.
　以上のようなサングラス用レンズの製造方法に、本発明の保護フィルムを適用することで、樹脂基板２１から保護フィルム１０を剥離させることなく前記工程［２］および前記工程［３］における樹脂基板２１の打ち抜きおよび熱曲げを実施することができるとともに、前記工程［４］における樹脂基板２１からの保護フィルム１０の剥離を樹脂基板２１に粘着層１１に由来する糊残りが生じるのを的確に抑制または防止して実施することができる。以下、本発明の保護フィルムについて詳述する。 By applying the protective film of the present invention to the method for manufacturing a lens for sunglasses as described above, the resin substrate 21 in the step [2] and the step [3] without peeling off the protective film 10 from the resin substrate 21. Punching and thermal bending can be carried out, and the peeling of the protective film 10 from the resin substrate 21 in the step [4] can be accurately suppressed or the occurrence of adhesive residue derived from the adhesive layer 11 on the resin substrate 21 can be accurately suppressed or It can be implemented with prevention. Hereinafter, the protective film of the present invention will be described in detail.
　なお、本発明の保護フィルム１０では、粘着層１１が、ポリオレフィンと、スチレンの含有量が２５ｗｔ％以下のスチレンブロックエラストマーとを含有すればよく、基材層１５の構成は、特に限定されない。以下では、基材層１５が第１の層１６と第２の層１７との積層体で構成される場合を一例に説明する。 In addition, in the protective film 10 of this invention, the adhesion layer 11 should just contain polyolefin and the styrene block elastomer whose content of styrene is 25 wt% or less, and the structure of the base material layer 15 is not specifically limited. Below, the case where the base material layer 15 is comprised with the laminated body of the 1st layer 16 and the 2nd layer 17 is demonstrated to an example.
　＜保護フィルム１０＞
　図２は、本発明の保護フィルムの好適実施形態を示す縦断面図である。なお、以下では、説明の都合上、図２の上側を「上」、下側を「下」と言う。 <Protective film 10>
FIG. 2 is a longitudinal sectional view showing a preferred embodiment of the protective film of the present invention. In the following, for convenience of explanation, the upper side of FIG. 2 is referred to as “upper” and the lower side is referred to as “lower”.
　保護フィルム１０は、基材層１５と、この基材層１５と樹脂基板２１との間に位置し、樹脂基板２１に粘着（接合）する粘着層１１とを有する。図２に示すように、基材層１５は、本実施形態では、粘着層１１の反対側、すなわち、成形型側に位置する第１の層１６と、粘着層１１側、すなわち、樹脂基板２１側に位置する第２の層１７とを有している。 The protective film 10 includes a base material layer 15 and an adhesive layer 11 that is located between the base material layer 15 and the resin substrate 21 and adheres (bonds) to the resin substrate 21. As shown in FIG. 2, in this embodiment, the base material layer 15 includes a first layer 16 located on the opposite side of the adhesive layer 11, that is, the mold side, and the adhesive layer 11 side, that is, the resin substrate 21. And a second layer 17 located on the side.
　以下、これら各層について詳述する。
　＜＜粘着層１１＞＞
　粘着層１１は、基材層１５と樹脂基板２１との間に位置（介在）し、樹脂基板２１に粘着する。このように、粘着層１１は、基材層１５を樹脂基板２１に接合する機能を有する。 Hereinafter, each of these layers will be described in detail.
<< Adhesion layer 11 >>
The adhesive layer 11 is positioned (intervened) between the base material layer 15 and the resin substrate 21 and adheres to the resin substrate 21. Thus, the adhesive layer 11 has a function of bonding the base material layer 15 to the resin substrate 21.
　この粘着層１１は、本発明では、前述の通り、ポリオレフィンと、スチレンの含有量が２５ｗｔ％以下のスチレンブロックエラストマーとを含有する。 In the present invention, as described above, the adhesive layer 11 contains polyolefin and a styrene block elastomer having a styrene content of 25 wt% or less.
　このように、粘着層１１が、スチレンの含有量が２５ｗｔ％以下のスチレンブロックエラストマーを含有することにより、前記工程［４］における樹脂基板２１からの保護フィルム１０の剥離の際に、樹脂基板２１に粘着層１１が残存することを的確に抑制または防止することができる。すなわち、樹脂基板２１における粘着層１１に由来する糊残りの発生を的確に抑制または防止することができる。 Thus, when the adhesive layer 11 contains a styrene block elastomer having a styrene content of 25 wt% or less, the resin substrate 21 is peeled off when the protective film 10 is peeled from the resin substrate 21 in the step [4]. It is possible to accurately suppress or prevent the adhesive layer 11 from remaining on the surface. That is, it is possible to accurately suppress or prevent the occurrence of adhesive residue derived from the adhesive layer 11 in the resin substrate 21.
　このスチレンブロックエラストマー（スチレンブロックを有するスチレン系エラストマー）としては、特に限定されないが、スチレン－オレフィン－スチレンブロック共重合体エラストマーであることが好ましい。このように、モノマー成分としてスチレンを含むスチレンブロックエラストマーとして、スチレン－オレフィン－スチレンブロック共重合体を用いることで、スチレンの含有量を２５ｗｔ％以下とした際に、前記工程［４］において、樹脂基板２１に糊残りが発生するのをより的確に抑制または防止することができる。 The styrene block elastomer (styrene elastomer having a styrene block) is not particularly limited, but is preferably a styrene-olefin-styrene block copolymer elastomer. As described above, when a styrene-olefin-styrene block copolymer is used as the styrene block elastomer containing styrene as a monomer component, and the styrene content is 25 wt% or less, the resin in the step [4] is used. Generation of adhesive residue on the substrate 21 can be more accurately suppressed or prevented.
　また、スチレン－オレフィン－スチレンブロック共重合体としては、例えば、スチレン－イソブチレン－スチレンブロック共重合体（ＳＩＢＳ）、スチレン－エチレン－ブチレン－スチレンブロック共重合体（ＳＥＢＳ）、スチレン－ブタジエン－スチレンブロック共重合体（ＳＢＳ）、スチレン－イソプレン－スチレン共重合体（ＳＩＳ）等が挙げられる。これらの中でも、スチレン－エチレン－ブチレン－スチレンブロック共重合体（ＳＥＢＳ）が好ましい。スチレン－オレフィン－スチレンブロック共重合体として、ＳＥＢＳを選択することにより、エラストマーにおけるスチレンの含有量を、比較的容易に２５ｗｔ％以下に設定することができ、前述した効果をより確実に得ることができる。 Examples of the styrene-olefin-styrene block copolymer include styrene-isobutylene-styrene block copolymer (SIBS), styrene-ethylene-butylene-styrene block copolymer (SEBS), and styrene-butadiene-styrene block. Examples thereof include a copolymer (SBS) and a styrene-isoprene-styrene copolymer (SIS). Among these, styrene-ethylene-butylene-styrene block copolymer (SEBS) is preferable. By selecting SEBS as the styrene-olefin-styrene block copolymer, the styrene content in the elastomer can be set to 25 wt% or less relatively easily, and the above-described effects can be obtained more reliably. it can.
　さらに、エラストマーにおけるスチレンの含有量は、２５ｗｔ％以下であればよいが、１０ｗｔ％以上１８ｗｔ％以下であることが好ましい。これにより、スチレン含有量が高くなることに起因して、粘着層１１の硬度の上昇を招くのを的確に抑制または防止することができる。そのため、粘着層１１の樹脂基板２１（被覆層２４）に対する密着力を確実に維持しつつ、樹脂基板２１に糊残りが発生するのをより的確に抑制または防止することができる。 Furthermore, the styrene content in the elastomer may be 25 wt% or less, but is preferably 10 wt% or more and 18 wt% or less. Thereby, it is possible to accurately suppress or prevent the increase in the hardness of the adhesive layer 11 due to the increase in the styrene content. Therefore, it is possible to more accurately suppress or prevent the occurrence of adhesive residue on the resin substrate 21 while reliably maintaining the adhesion of the adhesive layer 11 to the resin substrate 21 (covering layer 24).
　粘着層１１における、エラストマーの含有量は、特に限定されないが、好ましくは２０ｗｔ％以上８０ｗｔ％以下、より好ましくは３０ｗｔ％以上６０ｗｔ％以下に設定される。これにより、粘着層１１に、スチレンの含有量が２５ｗｔ％以下のスチレンブロックエラストマーを含有させることにより得られる効果を、より顕著に発揮させることができる。 The content of the elastomer in the adhesive layer 11 is not particularly limited, but is preferably set to 20 wt% or more and 80 wt% or less, more preferably 30 wt% or more and 60 wt% or less. Thereby, the effect acquired by making the adhesion layer 11 contain the styrene block elastomer whose content of styrene is 25 wt% or less can be exhibited more notably.
　また、粘着層１１は、本発明では、前述の通り、スチレンの含有量が２５ｗｔ％以下のスチレンブロックエラストマーの他に、ポリオレフィンを含有する。 In the present invention, the adhesive layer 11 contains a polyolefin in addition to the styrene block elastomer having a styrene content of 25 wt% or less as described above.
　このように、粘着層１１が、ポリオレフィンを含有することにより、樹脂基板２１から保護フィルム１０を剥離させることなく前記工程［２］および前記工程［３］における樹脂基板２１の打ち抜きおよび熱曲げを実施することができるとともに、前記工程［４］における樹脂基板２１からの保護フィルム１０の剥離を比較的容易に実施することができる。 As described above, since the adhesive layer 11 contains polyolefin, the resin substrate 21 is punched and thermally bent in the step [2] and the step [3] without peeling off the protective film 10 from the resin substrate 21. While being able to do, peeling of the protective film 10 from the resin substrate 21 in the said process [4] can be implemented comparatively easily.
　また、このポリオレフィンの融点は、１５０℃以上であることが好ましく、１５５℃以上１６０℃以下であることがより好ましい。ポリオレフィンの融点をこのような温度範囲に設定することにより、粘着層１１にポリオレフィンが含まれることにより得られる効果をより顕著に発揮させることができる。 The melting point of the polyolefin is preferably 150 ° C. or higher, more preferably 155 ° C. or higher and 160 ° C. or lower. By setting the melting point of the polyolefin within such a temperature range, the effect obtained by including the polyolefin in the adhesive layer 11 can be more remarkably exhibited.
　ここで、樹脂基板２１からの保護フィルム１０の易剥離性は、ピール強度を用いて表すことができる。具体的には、被覆層２４に、保護フィルム１０を貼付し、積層体を得る。その後、温度５０℃、時間１２ｈｒの条件で積層体を保管した後のＪＩＳ  Ｃ－６４８１：１９９６に準拠して測定される、被覆層２４と保護フィルム１０との間のピール強度Ｔ１、および、温度１５０℃、時間５ｍｉｎの条件で積層体を保管した後のＪＩＳ  Ｃ－６４８１：１９９６に準拠して測定される、被覆層２４と保護フィルム１０との間のピール強度Ｔ２は、それぞれ、０．０５Ｎ／２５ｍｍ以上３．０Ｎ／２５ｍｍ以下であることが好ましく、０．１０Ｎ／２５ｍｍ以上１．５Ｎ／２５ｍｍ以下であることがより好ましく、０．１５Ｎ／２５ｍｍ以上０．５Ｎ／２５ｍｍ以下であることがさらに好ましい。温度５０℃、時間１２ｈｒの条件および温度１５０℃、時間５ｍｉｎの条件で、それぞれ、積層体を保管した後のピール強度Ｔ１およびピール強度Ｔ２を前記範囲内とすることで、前記工程［２］および前記工程［３］における樹脂基板２１の打ち抜きおよび熱曲げを、樹脂基板２１から保護フィルム１０を剥離させることなく実施することができ、かつ、前記工程［３］における熱曲げによる熱履歴を保護フィルム１０が経たとしても、前記工程［４］における樹脂基板２１からの保護フィルム１０の剥離を確実に実施することができる。 Here, the easy peelability of the protective film 10 from the resin substrate 21 can be expressed using peel strength. Specifically, the protective film 10 is attached to the coating layer 24 to obtain a laminate. Thereafter, the peel strength T 1 between the coating layer 24 and the protective film 10 measured in accordance with JIS C-6481: 1996 after storing the laminate at a temperature of 50 ° C. for 12 hours, and The peel strength T 2 between the coating layer 24 and the protective film 10 measured in accordance with JIS C-6481: 1996 after storing the laminate at a temperature of 150 ° C. for 5 minutes is 0 0.05N / 25mm or more and 3.0N / 25mm or less is preferable, 0.10N / 25mm or more and 1.5N / 25mm or less is more preferable, and 0.15N / 25mm or more and 0.5N / 25mm or less. More preferably. By setting the peel strength T 1 and the peel strength T 2 after storing the laminated body within the above ranges under the conditions of a temperature of 50 ° C. and a time of 12 hours and a temperature of 150 ° C. and a time of 5 min, respectively, the step [2 ] And punching and thermal bending of the resin substrate 21 in the step [3] can be performed without peeling off the protective film 10 from the resin substrate 21, and the thermal history due to the thermal bending in the step [3] can be obtained. Even if the protective film 10 has passed, the protective film 10 can be reliably peeled from the resin substrate 21 in the step [4].
　また、ポリオレフィンとしては、特に限定されず、例えば、ポリプロピレンの単独重合体（ホモポリマー）、ポリエチレンの単独重合体、ＥＰＲ相（ゴム相）を備えるプロピレン－エチレンブロック共重合体、エチレン－酢酸ビニルブロック共重合体、エチレン－エチルアクリレートブロック共重合体、エチレン－メチルメタクリレートブロック共重合体等が挙げられ、これらのうちの１種または２種以上を組み合わせて用いることができる。これらの中でも、ポリプロピレンの単独重合体（ホモポリマー）が好ましい。ポリプロピレンの単独重合体は、比較的安価に入手することができ、さらに、融点が１５０℃以上のポリプロピレンの単独重合体も容易に入手することができる。また、ポリプロピレンの単独重合体であれば粘着層１１に透明性を付与することができる。そのため、基材層１５も同様に透明性を有している場合には、保護フィルム１０が透明性を備えることができる。したがって、前記工程［１］における保護フィルム１０の樹脂基板２１への貼付の際に、ホコリ等のゴミが保護フィルム１０と樹脂基板２１との間に介在しているか否かを視認し得る。そのため、前記工程［２］以降にゴミが介在している積層体１００が移行するのを確実に防止することができる。結果として、得られるサングラス用レンズ２００の歩留まりの向上が図られる。 The polyolefin is not particularly limited, and for example, a polypropylene homopolymer (homopolymer), a polyethylene homopolymer, a propylene-ethylene block copolymer having an EPR phase (rubber phase), an ethylene-vinyl acetate block Examples thereof include a copolymer, an ethylene-ethyl acrylate block copolymer, an ethylene-methyl methacrylate block copolymer, and the like, and one or more of them can be used in combination. Among these, a polypropylene homopolymer (homopolymer) is preferable. A polypropylene homopolymer can be obtained at a relatively low cost, and a polypropylene homopolymer having a melting point of 150 ° C. or higher can also be easily obtained. Moreover, if it is a homopolymer of a polypropylene, transparency can be provided to the adhesion layer 11. Therefore, when the base material layer 15 has transparency similarly, the protective film 10 can be provided with transparency. Therefore, when the protective film 10 is stuck on the resin substrate 21 in the step [1], it can be visually confirmed whether dust such as dust is interposed between the protective film 10 and the resin substrate 21. Therefore, it can prevent reliably that the laminated body 100 in which refuse exists after the said process [2] transfers. As a result, the yield of the obtained sunglasses lens 200 is improved.
　さらに、ポリオレフィンは、そのＪＩＳ  Ｋ７２１０に準拠して、加熱温度２３０℃、荷重２．１６ｋｇｆの条件下において測定されるメルトフローレート（ＭＦＲ）が０．５ｇ／１０ｍｉｎ以上１０．０ｇ／１０ｍｉｎ以下であることが好ましく、１．０ｇ／１０ｍｉｎ以上５．０ｇ／１０ｍｉｎ以下であることがより好ましく、２．０ｇ／１０ｍｉｎ以上３．５ｇ／１０ｍｉｎ以下であることがさらに好ましい。これにより、被覆層２４に対する初期の馴染み性に優れた粘着層１１が得られるため、前記工程［１］における保護フィルム１０の樹脂基板２１に対する貼付を、優れた密着性をもって行うことができる。 Further, the polyolefin has a melt flow rate (MFR) of 0.5 g / 10 min or more and 10.0 g / 10 min or less measured under the conditions of a heating temperature of 230 ° C. and a load of 2.16 kgf in accordance with JIS K7210. It is preferably 1.0 g / 10 min or more and 5.0 g / 10 min or less, more preferably 2.0 g / 10 min or more and 3.5 g / 10 min or less. Thereby, since the adhesion layer 11 excellent in the initial conformability with respect to the coating layer 24 is obtained, the sticking with respect to the resin substrate 21 of the protective film 10 in the said process [1] can be performed with the outstanding adhesiveness.
　なお、本明細書において、粘着層１１を含む保護フィルム１０を構成する各層の融点とは、それぞれ、各層に含まれる各構成材料の融点（ＤＳＣ測定によるピーク温度）に、それぞれ、各構成材料が含まれる比率を乗じたものの和により求められた値を融点とする。 In the present specification, the melting point of each layer constituting the protective film 10 including the adhesive layer 11 is the melting point of each constituent material included in each layer (peak temperature by DSC measurement). The value determined by the sum of the ratios contained is taken as the melting point.
　また、粘着層１１は、その平均厚さが５μｍ以上４０μｍ以下であることが好ましく、１０μｍ以上２０μｍ以下であることがより好ましい。これにより、前述した粘着層１１としての機能を確実に発揮させることができる。 The average thickness of the adhesive layer 11 is preferably 5 μm or more and 40 μm or less, and more preferably 10 μm or more and 20 μm or less. Thereby, the function as the adhesion layer 11 mentioned above can be exhibited reliably.
　＜＜基材層１５＞＞
　基材層１５は、粘着層１１を介して樹脂基板２１（被覆層２４）に接合される。基材層１５は、前記工程［２］および前記工程［３］における樹脂基板２１の打ち抜きおよび熱曲げの際に、樹脂基板２１を保護（マスキング）する機能層（保護層）として機能するものである。 << Base material layer 15 >>
The base material layer 15 is bonded to the resin substrate 21 (covering layer 24) through the adhesive layer 11. The base material layer 15 functions as a functional layer (protective layer) that protects (masks) the resin substrate 21 during the punching and thermal bending of the resin substrate 21 in the step [2] and the step [3]. is there.
　基材層１５は、かかる機能を発揮するものであれば、いかなる構成であってもよく、単層体または積層体のいずれであってもよい。本実施形態では、図２に示すように、基材層１５が、粘着層１１の反対側、すなわち、成形型側に位置する第１の層１６と、粘着層１１側、すなわち、樹脂基板２１側に位置する第２の層１７とを有する積層体で構成される場合について説明する。 The base material layer 15 may have any configuration as long as it exhibits such a function, and may be a single layer or a laminate. In the present embodiment, as shown in FIG. 2, the base material layer 15 includes a first layer 16 located on the opposite side of the adhesive layer 11, that is, the mold side, and the adhesive layer 11 side, that is, the resin substrate 21. The case where it comprises with the laminated body which has the 2nd layer 17 located in the side is demonstrated.
　＜＜第１の層１６＞＞
　第１の層１６は、粘着層１１の反対側、すなわち、前記工程［３］における熱曲げの際に、成形型側に位置して、樹脂基板２１を保護するための最外層として機能する。 << first layer 16 >>
The first layer 16 is located on the opposite side of the adhesive layer 11, that is, on the mold side during the thermal bending in the step [3], and functions as the outermost layer for protecting the resin substrate 21.
　この第１の層１６は、前記工程［３］における熱曲げの後に、成形型からの優れた離脱性を維持させること、すなわち、成形型（金型）に第１の層１６を密着させないことを目的に、第１の層１６の融点は、１５０℃以上であることが好ましく、１５５℃以上１６５℃以下程度であることがより好ましい。ここで、前述の通り、前記工程［３］における熱曲げの際の被覆層２４（樹脂基板２１）の加熱温度は、好ましくは、１１０℃以上１５０℃以下程度に設定される。そのため、第１の層１６の融点を前記の通り設定することにより、前記工程［３］における熱曲げの際に、第１の層１６が溶融または軟化状態となるのを確実に防止することができるため、前記工程［３］における熱曲げの後に、成形型から確実に積層体１００を離脱させることができる。 The first layer 16 maintains excellent detachability from the mold after the thermal bending in the step [3], that is, the first layer 16 does not adhere to the mold (mold). For this purpose, the melting point of the first layer 16 is preferably 150 ° C. or higher, more preferably about 155 ° C. or higher and 165 ° C. or lower. Here, as described above, the heating temperature of the coating layer 24 (resin substrate 21) during the thermal bending in the step [3] is preferably set to about 110 ° C. or more and 150 ° C. or less. Therefore, by setting the melting point of the first layer 16 as described above, it is possible to reliably prevent the first layer 16 from being melted or softened during the thermal bending in the step [3]. Therefore, the laminate 100 can be reliably detached from the mold after the thermal bending in the step [3].
　このような第１の層１６の構成材料としては、好ましくは融点が１５０℃以上である熱可塑性樹脂が挙げられ、より好ましくは融点が１５０℃以上のポリオレフィンが選択される。これにより、第１の層１６の融点を容易に１５０℃以上に設定することができる。また、後述する第２の層１７もポリオレフィンを含む構成とした際には、基材層１５（第１の層１６および第２の層１７）と粘着層１１との密着性を向上させることができるため、保護フィルム１０が備える各層において剥離が生じるのを的確に抑制または防止することができる。 Such a constituent material of the first layer 16 is preferably a thermoplastic resin having a melting point of 150 ° C. or higher, and more preferably a polyolefin having a melting point of 150 ° C. or higher. Thereby, melting | fusing point of the 1st layer 16 can be easily set to 150 degreeC or more. Moreover, when the 2nd layer 17 mentioned later is also set as the structure containing polyolefin, the adhesiveness of the base material layer 15 (1st layer 16 and 2nd layer 17) and the adhesion layer 11 can be improved. Since it can do, it can suppress or prevent exactly that peeling arises in each layer with which the protective film 10 is provided.
　なお、融点が１５０℃以上のポリオレフィンとしては、例えば、前述した粘着層１１に含まれるポリオレフィンのうち融点が１５０℃以上のポリオレフィンが挙げられる。 In addition, as a polyolefin whose melting | fusing point is 150 degreeC or more, polyolefin with a melting | fusing point of 150 degreeC or more is mentioned among the polyolefin contained in the adhesion layer 11 mentioned above, for example.
　また、第１の層１６は、その平均厚さが１０μｍ以上５０μｍ以下であることが好ましく、１５μｍ以上３５μｍ以下であることがより好ましい。これにより、前述した第１の層１６としての機能を確実に発揮させることができる。 The average thickness of the first layer 16 is preferably 10 μm or more and 50 μm or less, and more preferably 15 μm or more and 35 μm or less. Thereby, the function as the 1st layer 16 mentioned above can be exhibited reliably.
　＜＜第２の層１７＞＞
　第２の層１７は、粘着層１１側、すなわち、樹脂基板２１側に位置して、粘着層１１と第１の層１６との間に位置する中間層として機能する。 << second layer 17 >>
The second layer 17 is located on the adhesive layer 11 side, that is, on the resin substrate 21 side, and functions as an intermediate layer located between the adhesive layer 11 and the first layer 16.
　この第２の層１７は、前記工程［３］における熱曲げの際に溶融・軟化状態となり、積層体１００の熱曲げにより、積層体１００の湾曲面の縁部に第１の層１６が突出した掴みシロを形成させるための中間層として機能することを目的として、基材層１５に設けられている。このため、第２の層１７の融点は、１２０℃未満であることが好ましく、９０℃以上１１９℃以下程度であることがより好ましい。ここで、前述の通り、前記工程［３］における熱曲げの際の被覆層２４（樹脂基板２１）の加熱温度は、好ましくは、１１０℃以上１５０℃以下程度に設定される。そのため、第２の層１７の融点を前記の通り設定することにより、前記工程［３］における熱曲げの際に、第２の層１７を確実に溶融または軟化状態とすることができる。したがって、前記工程［３］において、この第２の層１７は、溶融または軟化状態の中間層としての機能を発揮して、樹脂基板２１の面方向に対して、第１の層１６を位置ずれさせ得る。その結果、積層体１００の縁部に第１の層１６による掴みシロが形成されることとなる。そのため、前記工程［４］における保護フィルム１０の剥離を、掴みシロを掴むことで実施し得ることから、この剥離を容易に行うことができる。 The second layer 17 is in a melted / softened state during the thermal bending in the step [3], and the first layer 16 protrudes at the edge of the curved surface of the laminated body 100 by the thermal bending of the laminated body 100. The base layer 15 is provided for the purpose of functioning as an intermediate layer for forming the gripping white. For this reason, it is preferable that melting | fusing point of the 2nd layer 17 is less than 120 degreeC, and it is more preferable that it is about 90 to 119 degreeC. Here, as described above, the heating temperature of the coating layer 24 (resin substrate 21) during the thermal bending in the step [3] is preferably set to about 110 ° C. or more and 150 ° C. or less. Therefore, by setting the melting point of the second layer 17 as described above, the second layer 17 can be surely brought into a molten or softened state during the thermal bending in the step [3]. Accordingly, in the step [3], the second layer 17 functions as an intermediate layer in a molten or softened state, and the first layer 16 is displaced with respect to the surface direction of the resin substrate 21. Can be. As a result, grabbing scissors by the first layer 16 are formed at the edge of the stacked body 100. Therefore, since peeling of the protective film 10 in the said process [4] can be implemented by grasping and holding this white, this peeling can be performed easily.
　また、この掴みシロの長さをＬ１とし、平面視で円形状をなす積層体１００が前記工程［３］により熱曲げされた後の平面視における直径をＬ２とし、前記工程［３］により熱曲げされた積層体１００の曲率半径Ｒを８．５ｃｍとしたとき、（Ｌ１／Ｌ２）×１００は、０．１％以上１％以下であることが好ましく、０．２％以上０．５％以下であることがより好ましい。かかる関係を満足することにより、前記工程［３］により形成される掴みシロを用いて、前記工程［４］における保護フィルム１０の剥離を、確実に実施することができる。 Further, the length of the gripping white and L 1, a diameter in plan view after it has been bent heat and L 2 laminate 100 forms a circular shape in plan view by the step [3], the step [3] (L 1 / L 2 ) × 100 is preferably 0.1% or more and 1% or less, and preferably 0.2% or more, when the curvature radius R of the laminated body 100 heat-bent by is set to 8.5 cm. More preferably, it is 0.5% or less. By satisfying such a relationship, the protective film 10 in the step [4] can be reliably peeled off using the gripping white formed in the step [3].
　このような第２の層１７の構成材料としては、好ましくは融点が１２０℃未満である熱可塑性樹脂が挙げられ、より好ましくは融点が１２０℃未満のポリオレフィンが選択される。これにより、第２の層１７の融点を容易に１２０℃未満に設定することができる。また、前述した第１の層１６もポリオレフィンを含む構成とした際には、基材層１５（第１の層１６および第２の層１７）と粘着層１１との密着性を向上させることができるため、保護フィルム１０が備える各層において剥離が生じるのを的確に抑制または防止することができる。 Such a constituent material of the second layer 17 is preferably a thermoplastic resin having a melting point of less than 120 ° C, and more preferably a polyolefin having a melting point of less than 120 ° C. Thereby, melting | fusing point of the 2nd layer 17 can be easily set to less than 120 degreeC. Further, when the first layer 16 described above also includes a polyolefin, the adhesion between the base material layer 15 (the first layer 16 and the second layer 17) and the adhesive layer 11 can be improved. Since it can do, it can suppress or prevent exactly that peeling arises in each layer with which the protective film 10 is provided.
　なお、融点が１２０℃未満のポリオレフィンとしては、前述した粘着層１１に含まれるポリオレフィンのうち、融点が１２０℃未満のポリオレフィンが挙げられる。例えば、融点が１２０℃未満のポリエチレンの単独重合体、α－オレフィン／ポリエチレン共重合体、α－オレフィン／ポリプロピレン共重合体等が挙げられる。 The polyolefin having a melting point of less than 120 ° C. includes a polyolefin having a melting point of less than 120 ° C. among the polyolefins contained in the adhesive layer 11 described above. Examples thereof include a polyethylene homopolymer having a melting point of less than 120 ° C., an α-olefin / polyethylene copolymer, an α-olefin / polypropylene copolymer, and the like.
　また、第２の層１７は、その平均厚さが１０μｍ以上６０μｍ以下であることが好ましく、１５μｍ以上３０μｍ以下であることがより好ましい。これにより、前述した第２の層１７としての機能を確実に発揮させることができる。 The average thickness of the second layer 17 is preferably 10 μm or more and 60 μm or less, and more preferably 15 μm or more and 30 μm or less. Thereby, the function as the 2nd layer 17 mentioned above can be exhibited reliably.
　なお、上述した保護フィルム１０が備える粘着層１１、基材層１５（第１の層１６および第２の層１７）の各層には、それぞれ、上述した構成材料の他に、酸化防止剤、光安定剤、帯電防止剤等の各種添加剤が含まれていてもよい。
　また、これら各層の間には、上記添加剤等を含む中間層が形成されていてもよい。 In addition to the above-described constituent materials, each of the adhesive layer 11 and the base material layer 15 (the first layer 16 and the second layer 17) included in the protective film 10 described above includes an antioxidant, a light Various additives such as a stabilizer and an antistatic agent may be contained.
Further, an intermediate layer containing the above-described additives and the like may be formed between these layers.
　さらに、上述した保護フィルム１０は、いかなる方法により製造されてもよいが、例えば、共押し出し法を用いることで製造し得る。 Furthermore, although the protective film 10 described above may be manufactured by any method, for example, it can be manufactured by using a coextrusion method.
　具体的には、３つの押し出し機を用意し、これらに、それぞれ、粘着層１１、第１の層１６および第２の層１７の構成材料を収納する。その後、これらの構成材料を溶融または軟化状態として、押し出す。これにより、共押し出しＴダイから、これらの構成材料が層状に積層された、溶融または軟化状態の積層体が得られる。得られた積層体を、複数の冷却ロール等で構成されるシート成形部に供給し、その後、このシート成形部において積層体を冷却することにより保護フィルム１０が製造される。 Specifically, three extruders are prepared, and the constituent materials of the adhesive layer 11, the first layer 16, and the second layer 17 are accommodated in these extruders, respectively. Thereafter, these constituent materials are extruded in a molten or softened state. As a result, a laminated body in a molten or softened state in which these constituent materials are laminated in layers is obtained from the co-extruded T-die. The protective film 10 is manufactured by supplying the obtained laminated body to the sheet | seat shaping | molding part comprised with a some cooling roll etc., and cooling a laminated body in this sheet | seat shaping | molding part after that.
　以上、本発明の保護フィルムについて説明したが、本発明は、これに限定されず、保護フィルムを構成する各層は、同様の機能を発揮し得る任意の構成の層と置換することができる。 As mentioned above, although the protective film of this invention was demonstrated, this invention is not limited to this, Each layer which comprises a protective film can be substituted with the layer of the arbitrary structures which can exhibit the same function.
　さらに、前記実施形態では、本発明の保護フィルムを、サングラス用レンズが有する樹脂基板に対して、熱曲げ加工する際に、樹脂基板に貼付して用いる場合について説明した。しかし、本発明の保護フィルムは、このようなサングラス用レンズが有する樹脂基板の熱曲げに適用できる他、例えば、ゴーグルが備えるレンズ、ヘルメットが備えるバイザー等の樹脂基板を熱曲げする際にも用いることができる。 Furthermore, in the above-described embodiment, the case where the protective film of the present invention is used by being attached to a resin substrate when the resin substrate included in the lens for sunglasses is hot-bent has been described. However, the protective film of the present invention can be applied to thermal bending of a resin substrate included in such a lens for sunglasses, and is also used when, for example, a resin substrate such as a lens provided in goggles or a visor provided in a helmet is thermally bent. be able to.
　以下、実施例に基づいて本発明をより具体的に説明する。なお、本発明はこれらの実施例によって何ら限定されない。 Hereinafter, the present invention will be described more specifically based on examples. In addition, this invention is not limited at all by these Examples.
　１．粘着層に含まれるエラストマーの種類の検討
　１－１．原材料の準備
　まず、各実施例および各比較例の保護フィルムの作製に使用した原料は以下の通りである。 1. 1. Examination of types of elastomer contained in adhesive layer 1-1. Preparation of raw materials First, the raw materials used for the production of the protective films of the examples and comparative examples are as follows.
＜ポリオレフィン＞
　融点が１４５℃のランダムポリプロピレン（日本ポリプロ社製、「ノバッテックＥＧ８Ｂ」、ＭＦＲ＝０．８ｇ／１０ｍｉｎ）
　融点が１５８℃のホモポリプロピレン（日本ポリプロ社製、「ノバッテックＥＡ９」、ＭＦＲ＝０．５ｇ／１０ｍｉｎ）
　融点が１１９℃の直鎖状低密度ポリエチレン（宇部丸善ポリエチレン社製、「ユリメット１５４０Ｆ」、ＭＦＲ＝４．０ｇ／１０ｍｉｎ） <Polyolefin>
Random polypropylene with a melting point of 145 ° C. (manufactured by Nippon Polypro Co., Ltd., “NOVATEC EG8B”, MFR = 0.8 g / 10 min)
Homopolypropylene having a melting point of 158 ° C. (manufactured by Nippon Polypro Co., Ltd., “NOVATEC EA9”, MFR = 0.5 g / 10 min)
Linear low-density polyethylene having a melting point of 119 ° C. ("Urimaru 1540F" manufactured by Ube Maruzen Polyethylene Co., Ltd., MFR = 4.0 g / 10 min)
＜エラストマー＞
　スチレン含有量が１２ｗｔ％のスチレン－エチレン－ブチレン－スチレンブロック共重合体（ＳＥＢＳ）（旭化成社製、「タフテックＨ１２２１」）
　スチレン含有量が２０ｗｔ％のスチレン－エチレン－ブチレン－スチレンブロック共重合体（ＳＥＢＳ）（旭化成社製、「タフテックＨ１０５２」）
　スチレン含有量が２０ｗｔ％のスチレン－イソブチレン－スチレンブロック共重合体（ＳＩＢＳ）（カネカ社製、「シブスター０６２Ｈ」）
　α－オレフィン／ポリプロピレン共重合体エラストマー（三井化学社製、「タフマーＰＮ２０６０」）
　α－オレフィン／ポリエチレン共重合体エラストマー（日本ポリエチレン社製、「カーネルＫＦ３５０」）
　スチレン含有量が３０ｗｔ％のスチレン－エチレン－ブチレン－スチレンブロック共重合体（ＳＥＢＳ）（旭化成社製、「製品番号タフテックＨ１０４１」） <Elastomer>
Styrene-ethylene-butylene-styrene block copolymer (SEBS) having a styrene content of 12 wt% (Asahi Kasei Co., Ltd., “Tuftec H1221”)
Styrene-ethylene-butylene-styrene block copolymer (SEBS) with a styrene content of 20 wt% ("Tough Tech H1052" manufactured by Asahi Kasei Corporation)
Styrene-isobutylene-styrene block copolymer (SIBS) with a styrene content of 20 wt% (manufactured by Kaneka Corporation, “Sibster 062H”)
α-Olefin / Polypropylene Copolymer Elastomer (Mitsui Chemicals, “Toughmer PN2060”)
α-olefin / polyethylene copolymer elastomer (manufactured by Nippon Polyethylene, “Kernel KF350”)
Styrene-ethylene-butylene-styrene block copolymer (SEBS) having a styrene content of 30 wt% (manufactured by Asahi Kasei Corporation, “Product No. Tuftec H1041”)
　１－２．保護フィルムの製造
　（実施例１Ａ）
　［１Ａ］まず、粘着層を形成するにあたり、スチレン含有量が１２ｗｔ％のＳＥＢＳと融点が１４５℃のランダムポリプロピレンとを、ＳＥＢＳの含有量が５０ｗｔ％となるように混練することで粘着層形成材料（樹脂組成物）を調製した。 1-2. Production of protective film (Example 1A)
[1A] First, when forming an adhesive layer, an adhesive layer forming material is prepared by kneading SEBS having a styrene content of 12 wt% and random polypropylene having a melting point of 145 ° C. so that the SEBS content is 50 wt%. (Resin composition) was prepared.
　［２Ａ］次に、調製した粘着層形成材料と、第２の層（中間層）形成材料として融点が１１９℃の低密度ポリエチレンと、第１の層（最外層）形成材料として融点が１５８℃のホモポリプロピレンとを、それぞれ、３つの押し出し機に収納した。 [2A] Next, the prepared adhesive layer forming material, low density polyethylene having a melting point of 119 ° C. as the second layer (intermediate layer) forming material, and melting point of 158 ° C. as the first layer (outermost layer) forming material Each of these homopolypropylenes was stored in three extruders.
　［３Ａ］次に、３つの押し出し機から、これらの形成材料を溶融状態として、押し出した。これにより、共押し出しＴダイから、これらの形成材料が層状に積層された溶融状態の積層体が得られた。その後、この積層体を冷却することで、実施例１Ａの保護フィルムを得た。 [3A] Next, these forming materials were extruded in a molten state from three extruders. Thereby, the laminated body of the molten state by which these formation materials were laminated | stacked in layer form from the co-extrusion T die was obtained. Then, the protective film of Example 1A was obtained by cooling this laminated body.
（実施例２Ａ～実施例７Ａ、比較例１Ａ～比較例３Ａ）
　前記工程［１Ａ］においてスチレン含有量が１２ｗｔ％のＳＥＢＳに代えて用いたエラストマーの種類、前記工程［１Ａ］において調製する粘着層形成材料に含まれるエラストマーの含有量、前記工程［３Ａ］において形成する積層体における粘着層の平均厚さを、それぞれ、表１に示すように変更したこと以外は、前記実施例１Ａと同様にして、実施例２Ａ～実施例７Ａ、比較例１Ａ～比較例３Ａの保護フィルムを得た。 (Example 2A to Example 7A, Comparative Example 1A to Comparative Example 3A)
Type of elastomer used in place of SEBS having a styrene content of 12 wt% in the step [1A], content of elastomer contained in the adhesive layer forming material prepared in the step [1A], formed in the step [3A] Example 2A to Example 7A and Comparative Example 1A to Comparative Example 3A were the same as Example 1A, except that the average thickness of the adhesive layer in each laminate was changed as shown in Table 1. A protective film was obtained.
　１－３．評価
　各実施例の保護フィルムを、以下の方法で評価した。 1-3. Evaluation The protective film of each Example was evaluated by the following method.
＜１＞熱曲げ前の密着性評価
　まず、各実施例および各比較例の保護フィルムについて、それぞれ、偏光子を２枚のポリカーボネート基板（ポリカーボネート層）で挾持（被覆）した構成をなす樹脂基板（住友ベークライト社製、「Ｐ１３５２」）を用意した。各保護フィルムを、各樹脂基板の両面に、荷重０．５ｋｇ／ｃｍ２の条件でロールを用いて圧着することで、保護フィルムを貼付することで積層体を得た。 <1> Adhesion evaluation before thermal bending First, for the protective film of each example and each comparative example, a resin substrate having a configuration in which a polarizer is held (covered) by two polycarbonate substrates (polycarbonate layers) ( “P1352” manufactured by Sumitomo Bakelite Co., Ltd.) was prepared. Each protective film was bonded to both surfaces of each resin substrate using a roll under the condition of a load of 0.5 kg / cm 2 , and a laminate was obtained by attaching the protective film.
　次いで、ＪＩＳ  Ｃ－６４８１：１９９６に準拠してポリカーボネート基板と保護フィルムとの間のピール強度を測定した。そして、得られたピール強度を、次の評価基準に基づいて、評価した。 Next, the peel strength between the polycarbonate substrate and the protective film was measured in accordance with JIS C-6481: 1996. And the obtained peel strength was evaluated based on the following evaluation criteria.
　　　Ａ：ピール強度が、０．１０Ｎ／２５ｍｍ以上１．５Ｎ／２５ｍｍ以下である。
　　　Ｂ：ピール強度が、０．０５Ｎ／２５ｍｍ以上０．１０Ｎ／ｍｍ未満、または、１．５Ｎ／２５ｍｍ超３．０Ｎ／２５ｍｍ以下である。
　　　Ｃ：ピール強度が、０．０５Ｎ／２５ｍｍ未満、または、３．０Ｎ／２５ｍｍ超である。 A: The peel strength is 0.10 N / 25 mm or more and 1.5 N / 25 mm or less.
B: The peel strength is 0.05 N / 25 mm or more and less than 0.10 N / mm, or 1.5 N / 25 mm or more and 3.0 N / 25 mm or less.
C: The peel strength is less than 0.05 N / 25 mm or more than 3.0 N / 25 mm.
＜２＞熱曲げ後の糊残り評価
　まず、各実施例および各比較例の保護フィルムについて、それぞれ、偏光子を２枚のポリカーボネート基板（ポリカーボネート層）で挾持した構成をなす樹脂基板（住友ベークライト社製、「Ｐ１３５２」）を用意した。各保護フィルムを、各樹脂基板の両面に、荷重０．５ｋｇ／ｃｍ２の条件でロールを用いて圧着することで、保護フィルムを貼付することで積層体を得た。 <2> Evaluation of adhesive residue after thermal bending First, for the protective films of each Example and each Comparative Example, a resin substrate (Sumitomo Bakelite Co., Ltd.) having a configuration in which a polarizer is held between two polycarbonate substrates (polycarbonate layers). Manufactured "P1352"). Each protective film was bonded to both surfaces of each resin substrate using a roll under the condition of a load of 0.5 kg / cm 2 , and a laminate was obtained by attaching the protective film.
　次いで、得られた積層体を、温度１５０℃の加熱温度で加熱しつつ、積層体を真空成形により熱曲げした。熱曲げした積層体について、ポリカーボネート基板から保護フィルムを剥離させ、その後、ポリカーボネート基板における糊残りの有無を観察した。そして、糊残りの有無の観察結果を、次の評価基準に基づいて、評価した。 Next, while heating the obtained laminate at a heating temperature of 150 ° C., the laminate was thermally bent by vacuum forming. About the laminated body which carried out the heat bending, the protective film was peeled from the polycarbonate substrate, and the presence or absence of the adhesive residue in a polycarbonate substrate was observed after that. And the observation result of the presence or absence of adhesive residue was evaluated based on the following evaluation criteria.
　　　Ａ：糊残りが全く認められない。
　　　Ｂ：若干の糊残りが認められる。
　　　Ｃ：明らかな糊残りが認められる。 A: No adhesive residue is observed at all.
B: Some glue residue is recognized.
C: A clear adhesive residue is observed.
　以上のようにして得られた各実施例および各比較例の保護フィルムにおける評価結果を、それぞれ、下記の表１に示す。 The evaluation results in the protective films of the examples and comparative examples obtained as described above are shown in Table 1 below.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示したように、各実施例では、保護フィルムの粘着層において、エラストマーとして、スチレン含有量が２５ｗｔ％以下のスチレン－オレフィン－スチレンブロック共重合体を用いた。このため、各実施例における保護フィルムでは、熱曲げした後のポリカーボネート基板と保護フィルムとの積層体において、ポリカーボネート基板から保護フィルムを、ポリカーボネート基板に糊残りを認めることなく、容易に剥離し得ることが明らかとなった。 As shown in Table 1, in each example, a styrene-olefin-styrene block copolymer having a styrene content of 25 wt% or less was used as the elastomer in the adhesive layer of the protective film. For this reason, in the protective film in each Example, in the laminate of the polycarbonate substrate and the protective film after heat bending, the protective film can be easily peeled from the polycarbonate substrate without any adhesive residue remaining on the polycarbonate substrate. Became clear.
　これに対して、各比較例における保護フィルムでは、粘着層に含まれるエラストマーとして、スチレンを含有しないエラストマー、または、スチレン含有量が２５ｗｔ％超のスチレン－オレフィン－スチレンブロック共重合体を用いた。このため、各比較例における保護フィルムでは、ポリカーボネート基板から保護フィルムを剥離した際に、ポリカーボネート基板に明らかな糊残りが認められる結果を示した。 On the other hand, in the protective film in each comparative example, an elastomer not containing styrene or a styrene-olefin-styrene block copolymer having a styrene content exceeding 25 wt% was used as the elastomer contained in the adhesive layer. For this reason, in the protective film in each comparative example, when the protective film was peeled off from the polycarbonate substrate, a clear adhesive residue was observed on the polycarbonate substrate.
　２．粘着層に含まれるポリオレフィンの融点の検討
　２－１．原材料の準備
　まず、各実施例の保護フィルムの作製に使用した原料は以下の通りである。 2. 2. Examination of melting point of polyolefin contained in adhesive layer 2-1. Preparation of raw materials First, the raw materials used for preparation of the protective film of each Example are as follows.
＜ポリオレフィン＞
　融点が１５８℃のホモポリプロピレン（住友化学社製、「ノーブレンＦＳ２０１１ＤＧ２」、ＭＦＲ＝２．５ｇ／１０ｍｉｎ）
　融点が１５８℃のホモポリプロピレン（日本ポリプロ社製、「ノバッテックＥＡ９」、ＭＦＲ＝０．５ｇ／１０ｍｉｎ）
　融点が１５８℃のホモポリプロピレン（住友化学社製、「ノーブレンＷＦ８３６ＤＧ３」、ＭＦＲ＝７．０ｇ／１０ｍｉｎ）
　融点が１５５℃のブロックポリプロピレン（ＥＰＲ相（ゴム相）を備えるプロピレン－エチレンブロック共重合体）（日本ポリプロ社製、「ノバッテックＥＣ９ＧＤ」、ＭＦＲ＝０．５ｇ／１０ｍｉｎ）
　融点が１４５℃のランダムポリプロピレン（日本ポリプロ社製、「ノバッテックＥＧ８Ｂ」、ＭＦＲ＝０．８ｇ／１０ｍｉｎ）
　融点が１１９℃の直鎖状低密度ポリエチレン（宇部丸善ポリエチレン社製、「ユリメット１５４０Ｆ」、ＭＦＲ＝４．０ｇ／１０ｍｉｎ）
　融点が１３２℃のランダムポリプロピレン（住友化学社製、「ノーブレンＳ１３１」、ＭＦＲ＝１．５ｇ／１０ｍｉｎ）
　融点が１２１℃の直鎖状低密度ポリエチレン（宇部丸善ポリエチレン社製、「ユリメット２５２５Ｆ」、ＭＦＲ＝２．５ｇ／１０ｍｉｎ）
　融点が９８℃の直鎖状低密度ポリエチレン（プライムポリマー社製、「エボリューＳＰ０５４０」、ＭＦＲ＝３．８ｇ／１０ｍｉｎ） <Polyolefin>
Homopolypropylene having a melting point of 158 ° C. (manufactured by Sumitomo Chemical Co., Ltd., “Nobrene FS2011DG2”, MFR = 2.5 g / 10 min)
Homopolypropylene having a melting point of 158 ° C. (manufactured by Nippon Polypro Co., Ltd., “NOVATEC EA9”, MFR = 0.5 g / 10 min)
Homopolypropylene having a melting point of 158 ° C. (manufactured by Sumitomo Chemical Co., Ltd., “Noblen WF836DG3”, MFR = 7.0 g / 10 min)
Block polypropylene having a melting point of 155 ° C. (propylene-ethylene block copolymer having an EPR phase (rubber phase)) (manufactured by Nippon Polypro Co., Ltd., “Novatech EC9GD”, MFR = 0.5 g / 10 min)
Random polypropylene with a melting point of 145 ° C. (manufactured by Nippon Polypro Co., Ltd., “NOVATEC EG8B”, MFR = 0.8 g / 10 min)
Linear low-density polyethylene having a melting point of 119 ° C. ("Urimaru 1540F" manufactured by Ube Maruzen Polyethylene Co., Ltd., MFR = 4.0 g / 10 min)
Random polypropylene having a melting point of 132 ° C. (manufactured by Sumitomo Chemical Co., Ltd., “Nobrene S131”, MFR = 1.5 g / 10 min)
Linear low-density polyethylene with a melting point of 121 ° C. (manufactured by Ube Maruzen Polyethylene Co., Ltd., “Urimet 2525F”, MFR = 2.5 g / 10 min)
Linear low-density polyethylene with a melting point of 98 ° C. (manufactured by Prime Polymer, “Evolue SP0540”, MFR = 3.8 g / 10 min)
＜エラストマー＞
　スチレン含有量が２０ｗｔ％のスチレン－エチレン－ブチレン－スチレンブロック共重合体（ＳＥＢＳ）（旭化成社製、「タフテックＨ１０５２」） <Elastomer>
Styrene-ethylene-butylene-styrene block copolymer (SEBS) with a styrene content of 20 wt% ("Tough Tech H1052" manufactured by Asahi Kasei Corporation)
　２－２．保護フィルムの製造
　（実施例１Ｂ）
　［１Ｂ］まず、粘着層を形成するにあたり、スチレン含有量が２０ｗｔ％のＳＥＢＳと融点が１５８℃のホモポリプロピレン（ノーブレンＦＳ２０１１ＤＧ２）とを、ＳＥＢＳの含有量が５０ｗｔ％となるように混練することで粘着層形成材料（樹脂組成物）を調製した。 2-2. Production of protective film (Example 1B)
[1B] First, in forming the adhesive layer, SEBS having a styrene content of 20 wt% and homopolypropylene (Nobrene FS2011DG2) having a melting point of 158 ° C. are kneaded so that the SEBS content is 50 wt%. An adhesive layer forming material (resin composition) was prepared.
　［２Ｂ］次に、調製した粘着層形成材料と、第２の層（中間層）形成材料として融点が１１９℃の直鎖状低密度ポリエチレンと、第１の層（最外層）形成材料として融点が１５８℃のホモポリプロピレン（ノバッテックＥＡ９）とを、それぞれ、３つの押し出し機に収納した。 [2B] Next, the prepared adhesive layer forming material, linear low density polyethylene having a melting point of 119 ° C. as the second layer (intermediate layer) forming material, and melting point as the first layer (outermost layer) forming material 158 ° C. homopolypropylene (Novatec EA9) was stored in each of three extruders.
　［３Ｂ］次に、３つの押し出し機から、これらの形成材料を溶融状態として、押し出した。これにより、共押し出しＴダイから、これらの形成材料が層状に積層された溶融状態の積層体が得られた。その後、この積層体を冷却することで、実施例１Ｂの保護フィルムを得た。 [3B] Next, these forming materials were extruded in a molten state from three extruders. Thereby, the laminated body of the molten state by which these formation materials were laminated | stacked in layer form from the co-extrusion T die was obtained. Then, the protective film of Example 1B was obtained by cooling this laminated body.
（実施例２Ｂ～実施例１３Ｂ）
　前記工程［１Ｂ］において１５８℃のホモポリプロピレン（ノーブレンＦＳ２０１１ＤＧ２）に代えて用いたポリオレフィンの種類、前記工程［１Ｂ］において調製する粘着層形成材料に含まれるエラストマーの含有量、前記工程［３Ｂ］において形成する積層体における粘着層の平均厚さを、それぞれ、表２に示すように変更したこと以外は、前記実施例１Ｂと同様にして、実施例２Ｂ～実施例１３Ｂの保護フィルムを得た。 (Example 2B to Example 13B)
In the step [1B], the type of polyolefin used in place of the 158 ° C. homopolypropylene (Nobrene FS2011DG2), the content of the elastomer contained in the adhesive layer forming material prepared in the step [1B], in the step [3B] Protective films of Examples 2B to 13B were obtained in the same manner as in Example 1B except that the average thickness of the adhesive layer in the laminate to be formed was changed as shown in Table 2.
　２－３．評価
　各実施例の保護フィルムを、以下の方法で評価した。 2-3. Evaluation The protective film of each Example was evaluated by the following method.
＜１＞熱履歴を経る前の密着強度評価
　まず、各実施例の保護フィルムについて、それぞれ、偏光子を２枚のポリカーボネート基板（ポリカーボネート層）で挾持した構成をなす樹脂基板（住友ベークライト社製、「Ｐ１３５２」）を用意した。各保護フィルムを、各樹脂基板の両面に、荷重０．５ｋｇ／ｃｍ２の条件でロールを用いて圧着することで、保護フィルムを貼付することで積層体を得た。 <1> Adhesion strength evaluation before passing through thermal history First, for the protective film of each example, a resin substrate (Sumitomo Bakelite, manufactured by Sumitomo Bakelite Co., Ltd.) having a polarizer held between two polycarbonate substrates (polycarbonate layers), respectively. “P1352”) was prepared. Each protective film was bonded to both surfaces of each resin substrate using a roll under the condition of a load of 0.5 kg / cm 2 , and a laminate was obtained by attaching the protective film.
　次いで、得られた積層体を、温度５０℃、時間１２ｈｒの条件で保管した後に、ＪＩＳ  Ｃ－６４８１：１９９６に準拠してポリカーボネート基板と保護フィルムとの間のピール強度Ｔ１を測定した。 Next, the obtained laminate was stored under the conditions of a temperature of 50 ° C. and a time of 12 hours, and then the peel strength T 1 between the polycarbonate substrate and the protective film was measured according to JIS C-6481: 1996.
＜２＞熱履歴を経た後の密着強度評価
　まず、各実施例の保護フィルムについて、それぞれ、偏光子を２枚のポリカーボネート基板（ポリカーボネート層）で挾持した構成をなす樹脂基板（住友ベークライト社製、「Ｐ１３５２」）を用意した。各保護フィルムを、各樹脂基板の両面に、荷重０．５ｋｇ／ｃｍ２の条件でロールを用いて圧着することで、保護フィルムを貼付することで積層体を得た。 <2> Adhesive strength evaluation after passing through thermal history First, for the protective film of each example, a resin substrate (Sumitomo Bakelite, manufactured by Sumitomo Bakelite Co., Ltd.) having a polarizer held between two polycarbonate substrates (polycarbonate layer), respectively. “P1352”) was prepared. Each protective film was bonded to both surfaces of each resin substrate using a roll under the condition of a load of 0.5 kg / cm 2 , and a laminate was obtained by attaching the protective film.
　次いで、得られた積層体を、温度１５０℃、時間５ｍｉｎの条件で保管した後に、ＪＩＳ  Ｃ－６４８１：１９９６に準拠してポリカーボネート基板と保護フィルムとの間のピール強度Ｔ２を測定した。 Next, the obtained laminate was stored under the conditions of a temperature of 150 ° C. and a time of 5 minutes, and then the peel strength T 2 between the polycarbonate substrate and the protective film was measured according to JIS C-6481: 1996.
　以上のようにして得られた各実施例の保護フィルムにおける評価結果を、それぞれ、下記の表２に示す。 The evaluation results in the protective films of the respective examples obtained as described above are shown in Table 2 below.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２に示したように、各実施例における保護フィルムでは、ポリオレフィンが粘着層に含まれることで、ピール強度Ｔ１、および、ピール強度Ｔ２ともに０．０５Ｎ／２５ｍｍ以上３．０Ｎ／２５ｍｍ以下の範囲内に設定された。このため、各実施例における保護フィルムを用いた場合、前記工程［２］および前記工程［３］における樹脂基板の打ち抜きおよび熱曲げを、樹脂基板から保護フィルムを剥離させることなく実施することができ、かつ、前記工程［３］における熱曲げによる熱履歴を保護フィルムが経たとしても、前記工程［４］における樹脂基板からの保護フィルムの剥離を実施することができる程度に、保護フィルムが樹脂基板に貼付されていることが判った。 As shown in Table 2, in the protective film in each example, the polyolefin was included in the adhesive layer, so that both the peel strength T 1 and the peel strength T 2 were 0.05 N / 25 mm or more and 3.0 N / 25 mm or less. Was set within the range. For this reason, when the protective film in each Example is used, the punching and thermal bending of the resin substrate in the step [2] and the step [3] can be performed without peeling off the protective film from the resin substrate. And even if a protective film passes through the thermal history by the thermal bending in the said process [3], a protective film is a resin substrate to such an extent that peeling of the protective film from the resin substrate in the said process [4] can be implemented. It was found that it was affixed to.
　本発明によれば、樹脂基板の熱曲げ加工時に剥離させることなく樹脂基板に貼付させることができるとともに、熱曲げ加工の後に樹脂基板から保護フィルムを剥離させる際に、粘着層に由来する糊残りが樹脂基板に生じるのを的確に抑制または防止し得る保護フィルムを提供することができる。したがって、本発明は、産業上の利用可能性を有する。 According to the present invention, the adhesive residue can be adhered to the resin substrate without being peeled off during the heat bending process of the resin substrate, and when the protective film is peeled off from the resin substrate after the heat bending process, It is possible to provide a protective film capable of accurately suppressing or preventing the occurrence of selenium on the resin substrate. Therefore, the present invention has industrial applicability.
　１０　　　　　保護フィルム
　１１　　　　　粘着層
　１５　　　　　基材層
　１６　　　　　第１の層
　１７　　　　　第２の層
　２１　　　　　樹脂基板
　２３　　　　　偏光子
　２４　　　　　被覆層
　３０　　　　　ポリカーボネート層
　１００　　　　積層体
　２００　　　　サングラス用レンズ DESCRIPTION OF SYMBOLS 10 Protective film 11 Adhesive layer 15 Base material layer 16 1st layer 17 2nd layer 21 Resin substrate 23 Polarizer 24 Covering layer 30 Polycarbonate layer 100 Laminate 200 Lens for sunglasses

Claims (8)

  1. 　樹脂基板に対して、加熱下で熱曲げ加工を施す際に、前記樹脂基板に貼付して用いられる保護フィルムであって、
    　基材層と、該基材層と前記樹脂基板との間に位置し、前記樹脂基板に粘着する粘着層とを有し、
    　前記粘着層は、ポリオレフィンと、スチレンの含有量が２５ｗｔ％以下のスチレンブロックエラストマーとを含有することを特徴とする保護フィルム。     When the resin substrate is subjected to thermal bending under heating, it is a protective film used by being affixed to the resin substrate,
    A base material layer, and an adhesive layer that is located between the base material layer and the resin substrate and adheres to the resin substrate;
    The said adhesion layer contains polyolefin and the styrene block elastomer whose content of styrene is 25 wt% or less, The protective film characterized by the above-mentioned.
  2. 　前記スチレンブロックエラストマーは、スチレン－オレフィン－スチレンブロック共重合体を含む請求項１に記載の保護フィルム。 The protective film according to claim 1, wherein the styrene block elastomer comprises a styrene-olefin-styrene block copolymer.
  3. 　前記ポリオレフィンは、その融点が１５０℃以上である請求項１または２に記載の保護フィルム。 The protective film according to claim 1 or 2, wherein the polyolefin has a melting point of 150 ° C or higher.
  4. 　前記ポリオレフィンは、そのＪＩＳ  Ｋ７２１０に準拠して加熱温度２３０℃、荷重２．１６ｋｇｆの条件下において測定されるメルトフローレートが０．５ｇ／１０ｍｉｎ以上１０．０ｇ／１０ｍｉｎ以下である請求項１ないし３のいずれか１項に記載の保護フィルム。 4. The polyolefin has a melt flow rate of 0.5 g / 10 min to 10.0 g / 10 min measured under conditions of a heating temperature of 230 ° C. and a load of 2.16 kgf in accordance with JIS K7210. The protective film of any one of these.
  5. 　前記ポリオレフィンは、ポリプロピレンのホモポリマーを含む請求項１ないし４のいずれか１項に記載の保護フィルム。 The protective film according to any one of claims 1 to 4, wherein the polyolefin includes a homopolymer of polypropylene.
  6. 　前記樹脂基板の両面に貼付される請求項１ないし５のいずれか１項に記載の保護フィルム。 The protective film according to any one of claims 1 to 5, which is attached to both surfaces of the resin substrate.
  7. 　前記樹脂基板の両面、一方の面または他方の面に、ポリカーボネート樹脂層、ポリアミド樹脂層およびセルロース樹脂層のうちの少なくとも１層を有する単層体または積層体で構成される被覆層が設けられる請求項１ないし６のいずれか１項に記載の保護フィルム。 A coating layer composed of a single layer or a laminate having at least one of a polycarbonate resin layer, a polyamide resin layer, and a cellulose resin layer is provided on both surfaces, one surface, or the other surface of the resin substrate. Item 7. The protective film according to any one of Items 1 to 6.
  8. 　前記樹脂基板は、プレス成形または真空成形により、前記熱曲げ加工される請求項１ないし７のいずれか１項に記載の保護フィルム。 The protective film according to any one of claims 1 to 7, wherein the resin substrate is subjected to the hot bending process by press molding or vacuum molding.
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JP2020037184A (en) * 2018-08-21 2020-03-12 住友ベークライト株式会社 Protective film
US11584870B2 (en) 2018-08-21 2023-02-21 Sumitomo Bakelite Co., Ltd. Protective film
WO2020203214A1 (en) * 2019-03-29 2020-10-08 東レフィルム加工株式会社 Layered film
JPWO2020203214A1 (en) * 2019-03-29 2020-10-08

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