WO2011099252A1

WO2011099252A1 - Laminated film

Info

Publication number: WO2011099252A1
Application number: PCT/JP2011/000548
Authority: WO
Inventors: 八束太一
Original assignee: 住友ベークライト株式会社
Priority date: 2010-02-09
Filing date: 2011-02-01
Publication date: 2011-08-18
Also published as: CN102762376A; SG183280A1; KR101745038B1; TW201144067A; CN102762376B; TWI532598B; KR20120125459A

Abstract

Disclosed is a laminated film which can be subjected to press bonding with good workability and enables the production of FPCs in improved yield. Specifically disclosed is a laminate film (100, 100A) which comprises a first mold release layer (110, 110a) and a cushion layer (120). The first mold release layer comprises a resin mainly composed of a polystyrene resin having a syndiotactic structure. The cushion layer comprises more than 60 parts by weight and not more than 98 parts by weight of a polyolefin resin and not less than 2 parts by weight and less than 40 parts by weight of a polystyrene resin having a syndiotactic structure. The cushion layer is arranged on one surface of the first mold release layer.

Description

Laminated film

The present invention relates to a laminated film.

Japanese Patent Application Laid-Open No. 2001-315273 discloses “a release layer composed of a resin mainly composed of syndiotactic polystyrene resin, and an elastomer resin alone, an olefin resin alone or a mixture thereof in 30 to 30 syndiotactic polystyrene resins. A laminated film comprising an intermediate layer composed of a mixed resin containing 60% by weight has been proposed. Such a laminated film is obtained by, for example, bonding a cover lay film (hereinafter referred to as “CL film”) to a flexible film (hereinafter referred to as “circuit exposed film”) having an exposed circuit through an adhesive with a hot press. It is used as a release film for producing a flexible printed circuit board (hereinafter referred to as “FPC”).

JP 2001-315273 A

However, as a result of the study by the inventors of the present application, the “laminated film containing a relatively large amount of syndiotactic polystyrene resin in the intermediate layer” as disclosed in JP-A-2001-315273 has a high elastic modulus. It was found that it was easy to break during pressing because of too much. If the laminated film breaks during pressing, the FPC may be damaged by the broken laminated film, and there is a risk that the defective product rate of the FPC will increase.

In addition, for such a laminated film, it becomes difficult to press the CL film uniformly on the circuit exposed film during the manufacture of FPC for the same reason as described above, and voids (minute void defects) are generated in the adhesive. It has been made clear by the inventor of the present application that the rate of defective FPCs tends to increase.

Also, such a laminated film has a very poor workability of the press set.

An object of the present invention is to provide a laminated film that can improve the workability of a press set and can increase the rate of non-defective products such as FPC.

(1)
The laminated film according to one aspect of the present invention includes a first release layer and a cushion layer (corresponding to an intermediate layer). The first release layer is formed from a resin whose main component is a polystyrene resin having a syndiotactic structure. The polystyrene resin having a syndiotactic structure is at least 70 parts by weight, preferably 85 parts by weight of the resin forming the first release layer, when the resin forming the first release layer is 100 parts by weight. It is preferable to occupy more than part. The cushion layer contains more than 60 parts by weight and less than 98 parts by weight of a polyolefin resin and 2 parts by weight or more and less than 40 parts by weight of a polystyrene resin having a syndiotactic structure. The cushion layer preferably contains 65 to 95 parts by weight of a polyolefin resin and 5 to 35 parts by weight of a polystyrene resin having a syndiotactic structure. The cushion layer is provided on one side of the first release layer. In addition, this cushion layer may be formed only from the polyolefin-type resin and the polystyrene-type resin which has a syndiotactic structure. Further, the cushion layer may contain a resin other than the polyolefin resin and the polystyrene resin having a syndiotactic structure as long as the gist of the present invention is not impaired.

As a result of intensive studies by the inventor of the present application, it becomes clear that the composition of the cushion layer is as described above, (i) workability of the press set is improved, and (ii) the elastic modulus of the laminated film is moderate. It becomes clear that the laminated film becomes difficult to break during pressing, and (iii) it becomes possible to uniformly press the CL film on the circuit exposed film during the manufacture of the FPC, and voids are formed in the adhesive. It became clear that (small cavity defects) were less likely to occur, and the non-defective rate of FPC was increased.
For this reason, this laminated film can improve the workability of the press set and can increase the rate of non-defective products such as FPC.

(2)
In the laminated film according to one aspect of the present invention, the polyolefin resin comprises 3 parts by weight or more and 40 parts by weight or less of a polypropylene resin and 20 parts by weight or more and 95 parts by weight or less of an ethylene-methyl methacrylate copolymer resin. It is preferable to contain. The polyolefin resin preferably contains 5 to 35 parts by weight of a polypropylene resin and 30 to 90 parts by weight of an ethylene-methyl methacrylate copolymer resin.

As a result of intensive studies by the present inventors, when the composition of the polyolefin resin in the cushion layer is as described above, the adhesion between the cushion layer and the first release layer can be improved without using a primer. It has become clear that the elastic modulus of the cushion layer can be further within an appropriate range.
For this reason, in this laminated film, a cushion layer and a 1st mold release layer can be adhere | attached favorably, and the elasticity modulus of a cushion layer can be kept further moderately.

(3)
In the laminated film according to one aspect of the present invention, the ethylene-methyl methacrylate copolymer resin preferably contains 5% by weight to 14% by weight of units derived from methyl methacrylate. The ethylene-methyl methacrylate copolymer resin may contain units derived from monomers other than ethylene and methyl methacrylate as long as the gist of the present invention is not impaired.

As a result of intensive studies by the inventor of the present application, when the content of units derived from methyl methacrylate is as described above, the adhesiveness between the cushion layer and the first release layer is good without using a primer. It became clear that it was possible to reduce the amount of stains on the hot platen of the end face of the cushion layer during pressing.

For this reason, in this laminated film, the cushion layer and the first release layer can be favorably bonded without using a primer. Moreover, this laminated film can reduce the amount of stains on the end face of the cushion layer during pressing.

(4)
In the laminated film according to one aspect of the present invention, the resin forming the first release layer preferably has a crystallinity measured by a differential scanning calorimetry of 14.0% or more and less than 30.0%. . In such a case, the first release layer may be integrated with the cushion layer via a primer, or may be directly integrated with the cushion layer without using a primer.

As a result of intensive studies by the inventors of the present application, when the crystallinity of the resin forming the first release layer is as described above, the circuit exposure film of the first release layer is bonded to the circuit exposure film when the CL film is adhered. And it became clear that better embedding property than the conventional release film can be obtained while preventing adhesion to the CL film.

For this reason, if this laminated film is used as a release film, the adhesion of the first release layer to the circuit exposed film and the CL film is prevented while adhering the CL film to the circuit exposed film. Also, good embedding property can be obtained.

This effect is
(I) The crystallinity of the resin forming the first release layer is set sufficiently low at the initial stage of the adhesion of the CL film to the circuit exposed film, and the first release layer is the cushion layer during the adhesion process. It is easy to follow the deformation of
(Ii) During the process of bonding the CL film to the circuit exposed film, the resin forming the first release layer is heated to crystallize, and the adhesion of the first release layer to the circuit exposed film and the CL film is improved. It is inferred that this is due to a sufficient decrease.

(5)
The laminated film according to one aspect of the present invention preferably further includes a second release layer. The second release layer is formed on the opposite side of the cushion layer from the first release layer forming side. The second release layer may be formed from a polymethylpentene resin, may be formed from a resin containing polymethylpentene resin as a main component, or a polystyrene-based resin having a syndiotactic structure. You may form from resin which has a main component, and you may form from other mold release resin. When the second release layer is formed of “polymethylpentene resin”, “resin mainly composed of polymethylpentene resin”, and “other release resin”, the second release layer includes a primer layer ( It may be bonded to the cushion layer via an adhesive layer. When the second release layer is formed from “resin mainly composed of a polystyrene resin having a syndiotactic structure”, the second release layer adheres to the cushion layer without using a primer (adhesive). can do.

Thus, when the second release layer is formed on the opposite side of the cushion layer to the first release layer forming side, the cushion layer is prevented from adhering to the press hot platen when the CL film is adhered to the circuit exposed film. Can do. For this reason, the time spent for the adhesion process etc. of CL film to a circuit exposure film can be shortened.

(6)
In the laminated film according to one aspect of the present invention, the second release layer is preferably formed from a resin whose main component is a polystyrene resin having a syndiotactic structure.

Thus, when the second release layer is formed from a resin whose main component is a polystyrene resin having a syndiotactic structure, it can be adhered to the cushion layer without using a primer (adhesive). For this reason, this laminated film can be manufactured while keeping material cost and process cost low.

(7)
In the laminated film according to one aspect of the present invention, the resin forming the second release layer preferably has a crystallinity measured by a differential scanning calorimetry of 14.0% or more and less than 30.0%. .

When the laminated film which concerns on 1 aspect of this invention is as above-mentioned (4), when the crystallinity degree of resin which forms a 2nd mold release layer is as above-mentioned, a 2nd mold release layer is a 1st mold release. It will have the same function as the layer. For this reason, in using this laminated film, the user does not need to specify the first release layer and the second release layer. For this reason, if this laminated film is used, it is possible to save the user from recognizing the first release layer and the second release layer, and to adhere the first release layer and the second release layer due to a specific mistake. Defects can be prevented.

It is a longitudinal cross-sectional view of the laminated film which concerns on embodiment of this invention. It is a longitudinal cross-sectional view of the laminated film which concerns on a modification (A). It is a figure which shows an example of the manufacturing apparatus of the laminated film which concerns on embodiment of this invention. It is a figure which shows an example of the usage method of the laminated | multilayer film based on embodiment of this invention. It is a figure which shows the heating pattern of a heating press when using the laminated | multilayer film which concerns on embodiment of this invention, and making CL film adhere to the uneven | corrugated | grooved part of a circuit pattern. It is a graph which shows the temperature dependence of the storage elastic modulus of the mold release layer of the laminated film which concerns on embodiment of this invention.

100, 100A laminated film 110 release layer (first release layer)
110a First release layer 110b Second release layer 120 Cushion layer

As shown in FIG. 1, the laminated film 100 according to the embodiment of the present invention mainly includes a release layer 110 and a cushion layer 120. In the present embodiment, the thickness of the laminated film 100 is preferably 25 to 300 μm.
Hereinafter, each of these layers will be described in detail.

1. Release Layer The release layer 110 is formed of a resin (hereinafter referred to as “release layer forming resin”) whose main component is a polystyrene resin having a syndiotactic structure (hereinafter referred to as “SPS resin”). . Such a release layer-forming resin is commercially available from Idemitsu Kosan Co., Ltd. under the trade name Zalek (registered trademark) (XAREC (registered trademark)). The content of the SPS resin in the release layer forming resin is 70% by weight or more and 90% by weight or less, but preferably 85% by weight or more and 90% by weight or less. In the present embodiment, the thickness of the release layer 110 is preferably 5 μm or more, and more preferably 10 μm or more. In the present embodiment, the crystallinity of the release layer forming resin is preferably 14.0% or more and less than 30.0% as measured by a differential scanning calorimeter (DSC). When the crystallinity of the release layer forming resin is as described above, the conventional release film while preventing adhesion of the release layer 110 to the circuit exposed film and the CL film when the CL film is adhered to the circuit exposed film This is because better embedding properties can be obtained. At this time, the temperature dependence of the storage elastic modulus of the release layer 110 is as shown in FIG.
Hereinafter, the components of the release layer forming resin will be described in detail.

(1) SPS resin SPS resin has a syndiotactic structure, that is, a stereoregulation in which phenyl groups and substituted phenyl groups which are side chains are alternately located in opposite directions with respect to the main chain formed from carbon-carbon sigma bonds. It is a resin having a structure.

As such an SPS resin, for example, as disclosed in JP-A-2000-038461, racemic dyad is 75% or more, preferably 85% or more, or racemic pentad, 30% or more, preferably Polystyrene, poly (alkyl styrene), poly (aryl styrene), poly (halogenated styrene), poly (halogenated alkyl styrene), poly (alkoxy styrene), poly (vinyl benzoic acid) having a syndiotacticity of 50% or more Esters), hydrogenated polymers thereof and mixtures thereof, or copolymers based on these.

Examples of poly (alkyl styrene) include poly (methyl styrene), poly (ethyl styrene), poly (isopropyl styrene), poly (t-butyl styrene), and the like.

Examples of poly (aryl styrene) include poly (phenyl styrene), poly (vinyl naphthalene), and poly (vinyl styrene).

Examples of poly (halogenated styrene) include poly (chlorostyrene), poly (bromostyrene), poly (fluorostyrene), and the like.

Examples of poly (halogenated alkylstyrene) include poly (chloromethylstyrene).

Examples of poly (alkoxystyrene) include poly (methoxystyrene) and poly (ethoxystyrene).

Of the above, polystyrene, poly (p-methylstyrene), poly (m-methylstyrene), poly (pt-ptylstyrene), poly (p-chlorostyrene), poly (m-chlorostyrene), Poly (p-fluorostyrene), hydrogenated polystyrene, and copolymers containing these structural units are particularly preferred.

(2) Resins other than SPS resin Examples of the resin other than the SPS resin constituting the release layer forming resin include, for example, elastomer resins, polyolefin resins, polystyrene resins, polyester resins, polyamide resins, polyphenylene ether resins, Polyphenylene sulfide resin (PPS) etc. are mentioned. In addition, these resin can be used individually or in combination of 2 or more types.

Examples of the elastomer resin include natural rubber, polybutadiene, polyisoprene, polyisobutylene, neoprene, polysulfide rubber, thiocol rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, styrene-butadiene block copolymer (SBR). ), Hydrogenated styrene-butadiene block copolymer (SEB), styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), styrene-isoprene block copolymer (SIR), hydrogenated styrene-isoprene block copolymer (SEP), styrene-isoprene-styrene block copolymer (SIS), hydrogenated styrene-isoprene-styrene block copolymer ( EPS), or olefin rubbers such as ethylene propylene rubber (EPM), ethylene propylene diene rubber (EPDM), linear low density polyethylene elastomer, or butadiene-acrylonitrile-styrene-core shell rubber (ABS), methyl methacrylate- Butadiene-styrene-core shell rubber (MBS), methyl methacrylate-butyl acrylate-styrene-core shell rubber (MAS), octyl acrylate-butadiene-styrene-core shell rubber (MABS), alkyl acrylate-butadiene-acrylonitrile-styrene-core shell rubber ( Silica-containing cores such as AABS), butadiene-styrene-core shell rubber (SBR), methyl methacrylate-butyl acrylate-siloxane Particulate elastic material of the core-shell type, such as Erugomu, or they were modified rubber, and the like.

Examples of polyolefin resins include linear high density polyethylene, linear low density polyethylene, high pressure low density polyethylene, isotactic polypropylene, syndiotactic polypropylene, block polypropylene, random polypropylene, polybutene, 1,2- Examples thereof include polybutadiene, poly (4-methylpentene), cyclic polyolefin, and copolymers thereof (for example, ethylene-methyl methacrylate copolymer).

Examples of polystyrene resins include atactic polystyrene, isotactic polystyrene, high impact polystyrene (HIPS), acrylonitrile-butadiene-styrene copolymer (ABS), acrylonitrile-styrene copolymer (AS), and styrene-meta. Acrylic acid copolymer, styrene-methacrylic acid / alkyl ester copolymer, styrene-methacrylic acid / glycidyl ester copolymer, styrene-acrylic acid copolymer, styrene-acrylic acid / alkyl ester copolymer, styrene -Maleic acid copolymer, styrene-fumaric acid copolymer and the like.

Examples of the polyester resin include polycarbonate, polyethylene terephthalate, and polybutylene terephthalate.

Examples of the polyamide-based resin include nylon (registered trademark) 6, nylon (registered trademark) 6, 6, and the like.

(3) Others For the mold release forming resin, various additives such as anti-blocking agent, antioxidant, nucleating agent, antistatic agent, process oil, plasticizer, mold release agent, flame retardant, flame retardant aid Agents, pigments, etc. may be blended.

In addition, examples of the antiblocking agent include the following inorganic particles or organic particles. Inorganic particles include Group IA, Group IIA, Group IVA, Group VIA, Group VIIA, Group VIIIA, Group IB, Group IIB, Group IIIB, Group IVB oxides, hydroxides, sulfides, nitrides, halogens , Carbonates, sulfates, acetates, phosphates, phosphites, organic carboxylates, silicates, titanates, borates and their water-containing compounds, and composite compounds and natural mineral particles centered on them Is mentioned.

Specific examples of such inorganic particles include group IA element compounds such as lithium fluoride and borax (sodium borate hydrate); magnesium carbonate, magnesium phosphate, magnesium oxide (magnesia), magnesium chloride, acetic acid Magnesium, magnesium fluoride, magnesium titanate, magnesium silicate, magnesium silicate hydrate (talc), calcium carbonate, calcium phosphate, calcium phosphite, calcium sulfate (gypsum), calcium acetate, calcium terephthalate, calcium hydroxide, silicic acid Group IIA element compounds such as calcium, calcium fluoride, calcium titanate, strontium titanate, barium carbonate, barium phosphate, barium sulfate, barium sulfite; titanium dioxide (titania), titanium monoxide, titanium nitride, two Group IVA element compounds such as zirconium fluoride (zirconia) and zirconium monoxide; Group VIA element compounds such as molybdenum dioxide, molybdenum trioxide and molybdenum sulfide; Group VIIA element compounds such as manganese chloride and manganese acetate; Cobalt chloride and cobalt acetate Group VIII element compounds; Group IB element compounds such as cuprous iodide; Group IIB element compounds such as zinc oxide and zinc acetate; Aluminum oxide (alumina), aluminum hydroxide, aluminum fluoride, alumina silicate (alumina silicate) Group IIIB element compounds such as silicon oxide (silica, silica gel), graphite, carbon, graphite, glass, etc .; Carnal stone, kainite, mica (mica, quinumo), villose ore, etc. And natural mineral particles.

Examples of the organic particles include fluororesins, melamine resins, styrene-divinylbenzene copolymers, acrylic resin silicones, and cross-linked products thereof.

The average particle diameter of the above-mentioned inorganic particles and organic particles is preferably 0.1 to 10 μm, and the addition amount is preferably 0.01 to 15% by weight.

In addition, these antiblocking agents can be used individually or in combination of 2 or more types.

Antioxidants include phosphorus antioxidants, phenolic antioxidants, sulfur antioxidants, 2-[(1-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4,6- And di-t-pentylphenyl acrylate. These antioxidants can be used alone or in combination of two or more.

Nucleating agents include metal salts of carboxylic acids such as aluminum di (pt-butylbenzoate), metal salts of phosphoric acid such as methylenebis (2,4-di-t-butylphenol) acid phosphate, talc, phthalocyanine derivatives Etc. In addition, these nucleating agents can be used individually or in combination of 2 or more types.

Examples of the plasticizer include polyethylene glycol, polyamide oligomer, ethylene bisstearamide, phthalate ester, polystyrene oligomer, polyethylene wax, silicone oil, and the like. In addition, these plasticizers can be used individually or in combination of 2 or more types.

Examples of the release agent include polyethylene wax, silicone oil, long chain carboxylic acid, and long chain carboxylic acid metal salt. In addition, these mold release agents can be used individually or in combination of 2 or more types.

Process oils include paraffinic oil, naphthenic oil, and aroma oil. Of these, paraffinic oils having a percentage of the total number of carbon atoms related to paraffin (straight chain) calculated by the ndM method of 60% Cp or more are preferable.

The viscosity of the process oil is preferably 15 to 600 cs at 40 ° C., more preferably 15 to 500 cs. The amount of process oil added is preferably from 0.01 to 1.5 parts by weight, more preferably from 0.05 to 1.4 parts by weight, based on 100 parts by weight of the release forming resin. More preferably, the content is 0.1 to 1.3 parts by weight. In addition, these process oil can be used individually or in combination of 2 or more types.

2. Cushion layer In the present embodiment, the cushion layer 120 is mainly formed from a resin blend of a polyolefin-based resin of more than 60 parts by weight and 98 parts by weight or less and an SPS resin of 2 parts by weight or more and less than 40 parts by weight. Yes. In addition, although this resin blend can be prepared by the dry blend method without pre-kneading, you may pre-process with a biaxial kneader. In the present embodiment, the thickness of the cushion layer 120 is preferably at least 3 times the thickness of the release layer 110, more preferably at least 5 times, and even more preferably at least 8 times.

Examples of polyolefin resins include linear high-density polyethylene, linear low-density polyethylene, high-pressure low-density polyethylene, isotactic polypropylene, syndiotactic polypropylene, block polypropylene, random polypropylene, polybutene, 1, Examples thereof include 2-polybutadiene, poly (4-methylpentene), cyclic polyolefin, and copolymers thereof (for example, ethylene-methyl methacrylate copolymer).

The SPS resin is the same as the SPS resin described above.

The cushion layer 120 includes 2 parts by weight or more and less than 40 parts by weight of an SPS resin, 3 parts by weight or more and 40 parts by weight or less of a polypropylene resin, and more than 20 parts by weight of 95 parts by weight or less of an ethylene-methyl methacrylate copolymer. More preferably, it is formed from a resin blend with resin. In such a case, the ethylene-methyl methacrylate copolymer resin preferably contains 5% by weight to 14% by weight of units derived from methyl methacrylate. When the composition of the cushion layer 120 and the composition of the ethylene-methyl methacrylate copolymer resin are as described above, (i) good adhesion between the cushion layer 120 and the release layer 110 without using a primer. This is because (ii) it is possible to reduce the amount of smearing of the end face of the cushion layer 120 to the hot platen during pressing.

In addition, the above-mentioned elastomer resin and additives may be blended with the resin blend as necessary, as long as the gist of the present invention is not impaired.

<Method for producing laminated film>
The laminated film 100 according to the present embodiment can be manufactured by a method such as a coextrusion method or an extrusion lamination method.

In the coextrusion method, the laminated film 100 is manufactured by simultaneously extruding the release layer 110 and the cushion layer 120 using a feed block and a multi-manifold die. In the coextrusion method, the melt M that has passed through the die 210 is guided between the first roll 230 and the touch roll 220 as shown in FIG. The laminated film 100 is cooled by the touch roll 220 and the first roll 230. Thereafter, the laminated film 100 is sent to the downstream side in the film feeding direction (see the arrow in FIG. 3) by the second roll 240 and is finally taken up by a take-up roll (not shown). At this time, the temperature of the first roll 230 is preferably 30 to 100 ° C., the temperature of the touch roll 220 is preferably 50 to 120 ° C., and the peripheral speed of the second roll 240 with respect to the first roll 230. The ratio is preferably from 0.990 to 0.998.

In the extrusion laminating method, the temperature of the extruder cylinder is set to 270 to 300 ° C., the release layer 110 is extruded, and the release layer 110 and the cushion layer 120 are joined together to form the release layer 110 and the cushion layer 120. The laminated film 100 is manufactured by laminating. In the extrusion laminating method, the release layer forming resin melt M that has passed through the die 210 is guided between the first roll 230 and the touch roll 220 as shown in FIG. Until it is detached, it is cooled by the touch roll 220 and the first roll 230 to form the release layer film F. Thereafter, the release layer film F is sent downstream by the second roll 240 in the film feeding direction (see the arrow in FIG. 3). And the melt (not shown) of the resin blend that forms the cushion layer 120 is merged with the release layer film F sent to the downstream side in the film feed direction and integrated with the release layer film F, The laminated film 100 is manufactured. In addition, the laminated | multilayer film 100 manufactured in this way is wound up by the winding roll (not shown) further provided in the film feed direction downstream. Also at this time, the temperature of the first roll 230 is preferably 30 to 100 ° C., the temperature of the touch roll 220 is preferably 50 to 120 ° C., and the circumference of the second roll 240 with respect to the first roll 230 is preferred. The speed ratio is preferably 0.990 to 0.998.

If necessary, the crystallinity of the SPS resin in the release layer 110 of the laminated film 100 obtained as described above may be adjusted by a known heat treatment apparatus. For example, heat treatment may be performed in the vicinity of 50 to 220 ° C. using a method of heat-setting the laminated film 100 in a dryer using a tenter device or a heat treatment roll.

<Example of use of laminated film>
The laminated film 100 according to the embodiment of the present invention is disposed so as to wrap the CL film so that the CL film adheres to the concavo-convex portion of the circuit pattern when the CL film is adhered to the circuit exposed film, and together with the circuit exposed film and the CL film. Pressurized by a press device. Specifically, as shown in FIG. 4, the laminated film 100 is obtained by sandwiching a circuit-exposed film and a CL film temporarily fixed with an adhesive 340 so that the release layer 110 faces each other. The sheet is sequentially sandwiched between a Teflon (registered trademark) sheet 330, a rubber cushion 320, and a stainless steel plate 310, and pressed by a hot platen 300 (see white arrows in FIG. 4). The heating method using the hot platen 300 is as shown in FIG. That is, the hot platen 300 is rapidly heated from room temperature to 185 ° C. in 10 seconds after the start of pressurization, and then maintained at that temperature for 60 seconds. Note that pressurization by the hot platen 300 is started at the time of 0 seconds and released at the time of 70 seconds. The pressing pressure at this time is appropriately adjusted to 5 to 15 MPa.

(A)
In the previous embodiment, the laminated film 100 in which the release layer 110 is provided only on one side of the cushion layer 120 was introduced. However, as shown in FIG. 2, the release layers 110a and 110b on both sides of the cushion layer 120. A laminated film 110 </ b> A provided with is also included in one embodiment of the present invention. Hereinafter, the release layer denoted by reference numeral 110a is referred to as a “first release layer”, and the release layer denoted by reference numeral 110b is referred to as a “second release layer”.

The first release layer 110a has the same structure as the release layer 110 according to the previous embodiment. On the other hand, the second release layer 110b may have the same structure as the first release layer 110a, or may have a different structure from the first release layer 110a. In the latter case, the second release layer 110b is formed of, for example, a resin mainly composed of polymethylpentene resin or methylpentene-α olefin copolymer. Such a resin is commercially available from Mitsui Chemicals, Inc. under the trade name TPX (registered trademark). In such a case, the adhesive force between the second release layer 110b and the cushion layer 120 may be reduced. In such a case, an anchor layer or a primer layer is interposed between the second release layer 110b and the cushion layer 120. (Adhesive layer) may be interposed.

(B)
In the example of use of the laminated film according to the previous embodiment, the Teflon (registered trademark) sheet 330, the rubber cushion 320, and the stainless steel plate 310 are sequentially sandwiched between the laminated film 100 and the heating platen 300. The (registered trademark) sheet 330, the rubber cushion 320, and the stainless steel plate 310 may be omitted.

<Example>
Hereinafter, the present invention will be described in more detail with reference to examples.

1. Production of laminated film

(1) Release Layer Raw Material As a release layer raw material, SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.) was used.

(2) Cushion Layer Raw Material The cushion layer raw material is 20 parts by weight of SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.) and 75 parts by weight of ethylene-methyl methacrylate copolymer. Combined (methyl methacrylate derived unit content: 5% by weight) (Aclift (registered trademark) WD106 manufactured by Sumitomo Chemical Co., Ltd.) and 5 parts by weight of polypropylene (Nobrene FH1016 manufactured by Sumitomo Chemical Co., Ltd.) What was dry blended (hereinafter referred to as “cushion layer forming blend resin”) was used.

(3) Production of Laminated Film A laminated film (see FIG. 2) having the same release layer on the front and back of the cushion layer was produced using a coextrusion method.

Specifically, SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.), cushion layer forming blend resin and SPS resin (Idemitsu Kosan Co., Ltd.) using a feed block and a multi-manifold die. Zalek (registered trademark) S104 manufactured by the company was simultaneously extruded to produce a laminated film. At this time, the apparatus shown in FIG. 3 was used, but the temperature of the first roll 230 was 30 ° C., the temperature of the touch roll 220 was 70 ° C., and the circumference of the second roll 240 with respect to the first roll 230 was changed. The speed ratio was 0.990.

The thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

2. Evaluation of laminated film

(1) Workability of press set A sensory test was conducted by an operator. As a result, the workability of the above-described laminated film press set was good (see Table 1).

(2) Void Observation When the FPC after pressing was observed with an optical microscope, no void was found in the FPC (see Table 1).

(3) CL film adhesion test Actually, the circuit-exposed film in which the CL film was temporarily fixed via an adhesive was wrapped from both sides with the laminated film, and was hot-pressed with a heating pattern shown in FIG. . As a result, no crack occurred in the laminated film (see Table 1). The amount of the adhesive between the circuit-exposed film and the CL film spilled into the circuit pattern was less than 100 μm and was within an allowable range (see Table 1). The amount of the stain on the end face of the cushion layer was less than 5 mm and was within an allowable range (see Table 1).

As a cushion layer forming blend resin, 20 parts by weight of SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.) and 70 parts by weight of ethylene-methyl methacrylate copolymer (methyl methacrylate derived) Unit content: 5% by weight) (Acrylift (registered trademark) WD106 manufactured by Sumitomo Chemical Co., Ltd.) and 10 parts by weight of polypropylene (Nobrene FH1016 manufactured by Sumitomo Chemical Co., Ltd.) were used. A laminated film was produced in the same manner as in Example 1 except that the laminated film was evaluated.

As a result of the evaluation, the workability of this laminated film press set was good (see Table 1). No voids were found in the FPC after pressing (see Table 1). This laminated film was not cracked even after hot pressing (see Table 1). The amount of the adhesive between the circuit-exposed film and the CL film spilled into the circuit pattern was less than 100 μm and was within an allowable range (see Table 1). The amount of the stain on the end face of the cushion layer was less than 5 mm and was within an allowable range (see Table 1).

As cushion layer forming blend resin, 20 parts by weight of SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.) and 60 parts by weight of ethylene-methyl methacrylate copolymer (methyl methacrylate derived) (Unit content: 5% by weight) (Akulift (registered trademark) WD106 manufactured by Sumitomo Chemical Co., Ltd.) and 20 parts by weight of polypropylene (Nobrene FH1016 manufactured by Sumitomo Chemical Co., Ltd.) were used. A laminated film was produced in the same manner as in Example 1 except that the laminated film was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

As a cushion layer forming blend resin, 20 parts by weight of SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.) and 50 parts by weight of ethylene-methyl methacrylate copolymer (methyl methacrylate derived) (Unit content: 5% by weight) (Aclift (registered trademark) WD106 manufactured by Sumitomo Chemical Co., Ltd.) and 30 parts by weight of polypropylene (Nobrene FH1016 manufactured by Sumitomo Chemical Co., Ltd.) were used. A laminated film was produced in the same manner as in Example 1 except that the laminated film was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

As a cushion layer forming blend resin, 20 parts by weight of SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.) and 70 parts by weight of ethylene-methyl methacrylate copolymer (methyl methacrylate derived) Unit content: 10% by weight) (Acrylift (registered trademark) WD201 manufactured by Sumitomo Chemical Co., Ltd.) and 10 parts by weight of polypropylene (Nobrene FH1016 manufactured by Sumitomo Chemical Co., Ltd.) were used. A laminated film was produced in the same manner as in Example 1 except that the laminated film was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

As a result of evaluation, the workability of the press set of this laminated film was good (see Table 2). No voids were found in the FPC after pressing (see Table 2). This laminated film did not crack even after hot pressing (see Table 2). The amount of the adhesive between the circuit-exposed film and the CL film spilled into the circuit pattern was less than 100 μm and was within an allowable range (see Table 2). The amount of the stain on the end face of the cushion layer was less than 5 mm and was within the allowable range (see Table 2).

As a cushion layer forming blend resin, 20 parts by weight of SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.) and 70 parts by weight of ethylene-methyl methacrylate copolymer (methyl methacrylate derived) Unit content: 14% by weight) (Acrylift (registered trademark) CM8033 manufactured by Sumitomo Chemical Co., Ltd.) and 10 parts by weight of polypropylene (Nobrene FH1016 manufactured by Sumitomo Chemical Co., Ltd.) were used. A laminated film was produced in the same manner as in Example 1 except that the laminated film was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

As a cushion layer-forming blend resin, 39 parts by weight of SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.) and 21 parts by weight of ethylene-methyl methacrylate copolymer (methyl methacrylate derived) Unit content: 14% by weight) (Acrylift (registered trademark) CM8033 manufactured by Sumitomo Chemical Co., Ltd.) and 40 parts by weight of polypropylene (Nobrene FH1016 manufactured by Sumitomo Chemical Co., Ltd.) were used. A laminated film was produced in the same manner as in Example 1 except that the laminated film was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

As a cushion layer-forming blend resin, 5 parts by weight of SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.) and 90 parts by weight of ethylene-methyl methacrylate copolymer (methyl methacrylate derived) Unit content: 14% by weight) (Acrylift (registered trademark) CM8033 manufactured by Sumitomo Chemical Co., Ltd.) and 5 parts by weight of polypropylene (Nobrene FH1016 manufactured by Sumitomo Chemical Co., Ltd.) were used. A laminated film was produced in the same manner as in Example 1 except that the laminated film was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

As a cushion layer forming blend resin, 20 parts by weight of SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.) and 80 parts by weight of ethylene-methyl methacrylate copolymer (methyl methacrylate derived) A laminated film was prepared in the same manner as in Example 1 except that a dry blend of (unit content: 5% by weight) (Aclift (registered trademark) WD106 manufactured by Sumitomo Chemical Co., Ltd.) was used. Was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

As a result of the evaluation, the workability of this laminated film press set was good (see Table 3). No voids were found in the FPC after pressing (see Table 3). This laminated film did not crack even after hot pressing (see Table 3). The amount of the adhesive between the circuit-exposed film and the CL film oozed out into the circuit pattern was less than 100 μm, and was within an allowable range (see Table 3). However, the amount of the stain on the end face of the cushion layer was 5 mm or more, which was outside the allowable range (see Table 3).

As a cushion layer forming blend resin, 20 parts by weight of SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.) and 70 parts by weight of ethylene-methyl methacrylate copolymer (methyl methacrylate derived) Unit content: 20% by weight) (Acrylift (registered trademark) WH206 manufactured by Sumitomo Chemical Co., Ltd.) and 10 parts by weight of polypropylene (Nobrene FH1016 manufactured by Sumitomo Chemical Co., Ltd.) were used. A laminated film was produced in the same manner as in Example 1 except that the laminated film was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

As a cushion layer forming blend resin, 20 parts by weight of SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.) and 70 parts by weight of ethylene-methyl methacrylate copolymer (methyl methacrylate derived) Unit content: 17.5% by weight (Akulift (registered trademark) CM8014 manufactured by Sumitomo Chemical Co., Ltd.) and 10 parts by weight of polypropylene (Nobrene FH1016 manufactured by Sumitomo Chemical Co., Ltd.) A laminated film was produced in the same manner as in Example 1 except that the laminated film was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

1. Production of laminated film

(2) Cushion Layer Raw Material The cushion layer raw material is 20 parts by weight of SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.) and 70 parts by weight of ethylene-methyl methacrylate copolymer. Combined (Methyl methacrylate derived unit content: 5% by weight) (Akulift (registered trademark) WD106 manufactured by Sumitomo Chemical Co., Ltd.) and 10 parts by weight of polypropylene (Nobrene FH1016 manufactured by Sumitomo Chemical Co., Ltd.) What was dry blended (hereinafter referred to as “cushion layer forming blend resin”) was used.

Specifically, a multi-manifold die was used to simultaneously extrude SPS resin, cushion layer forming blend resin, and SPS resin to produce a laminated film. In this case, although the apparatus shown in FIG. 3 was used, the temperature of the first roll 230 was 35 ° C., the temperature of the touch roll 220 was 70 ° C., and the circumference of the second roll 240 with respect to the first roll 230 was changed. The speed ratio was 0.998.

2. Evaluation of laminated film

(1) Workability of press set A sensory test was conducted by an operator. As a result, the workability of the above-described laminated film press set was good (see Table 4).

(2) Void Observation When the FPC after pressing was observed with an optical microscope, no void was found in the FPC (see Table 4).

(3) CL film adhesion test Actually, the circuit-exposed film in which the CL film was temporarily fixed via an adhesive was wrapped from both sides with the laminated film, and was hot-pressed with a heating pattern shown in FIG. . Thereafter, the laminated film could be easily peeled from the circuit exposed film and the CL film (see Table 4). Further, no cracks occurred in the laminated film (see Table 4). The amount of the adhesive between the circuit-exposed film and the CL film oozed out into the circuit pattern was less than 80 μm, which was superior to the conventional release film (see Table 4). The amount of the stain on the end face of the cushion layer was less than 5 mm and was within an allowable range (see Table 4).
(4) Measurement of crystallinity of release layer The release layer was peeled off from the above laminated film, and the release layer piece was heated at a rate of 20 ° C / min with a differential scanning calorimeter, and the melting enthalpy (ΔHf ) And cold crystallization enthalpy (ΔH _Tcc ). Then, the crystallinity of the release layer was calculated by substituting the melting enthalpy (ΔHf) and the cold crystallization enthalpy (ΔH _Tcc ) into the following equation, and the value was 15.8% ( (See Table 4)
Crystallinity (%) = 100 × (ΔH _f _{−ΔH Tcc} ) / 53 (J / g)

Example 12 is the same as Example 12 except that the temperature of the first roll 230 is set to 98 ° C., the temperature of the touch roll 220 is set to 120 ° C., and the peripheral speed ratio of the second roll 240 to the first roll 230 is set to 0.998. A laminated film was produced and the laminated film was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

As a result of the evaluation, the workability of this laminated film press set was good (see Table 4). No voids were found in the FPC after pressing (see Table 4). This laminated film was not cracked even after hot pressing (see Table 4). The amount of the adhesive between the circuit-exposed film and the CL film oozed out into the circuit pattern was less than 80 μm, which was superior to the conventional release film (see Table 4). The amount of the stain on the end face of the cushion layer was less than 5 mm and was within an allowable range (see Table 4). The crystallinity of the release layer of this laminated film was 17.3% (see Table 4). The laminated film could be easily peeled from the circuit exposed film and the CL film (see Table 4).

The temperature of the first roll 230 was set to 35 ° C., the temperature of the touch roll 220 was set to 70 ° C., and the peripheral speed ratio of the second roll 240 to the first roll 230 was set to 0.998, as in Example 12. A laminated film was prepared, and the laminated film was further annealed by being sandwiched between stainless plates with a surface temperature of 120 ° C. and held at a pressure of 10 MPa for 10 minutes, and then the laminated film was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

As a result of the evaluation, the workability of this laminated film press set was good (see Table 4). No voids were found in the FPC after pressing (see Table 4). This laminated film was not cracked even after hot pressing (see Table 4). The amount of the adhesive between the circuit-exposed film and the CL film oozed out into the circuit pattern was less than 80 μm, which was superior to the conventional release film (see Table 4). The amount of the stain on the end face of the cushion layer was less than 5 mm and was within an allowable range (see Table 4). The crystallinity of the release layer of this laminated film was 20.5% (see Table 4). The laminated film could be easily peeled from the circuit exposed film and the CL film (see Table 4).

The temperature of the first roll 230 was set to 35 ° C., the temperature of the touch roll 220 was set to 70 ° C., and the peripheral speed ratio of the second roll 240 to the first roll 230 was set to 0.998, as in Example 12. A laminated film was prepared, and the laminated film was further annealed by being sandwiched between stainless plates having a surface temperature of 125 ° C. and held at a pressure of 10 MPa for 10 minutes, and then the laminated film was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

As a result of the evaluation, the workability of this laminated film press set was good (see Table 4). No voids were found in the FPC after pressing (see Table 4). This laminated film was not cracked even after hot pressing (see Table 4). The amount of the adhesive between the circuit-exposed film and the CL film oozed out into the circuit pattern was less than 80 μm, which was superior to the conventional release film (see Table 4). The amount of the stain on the end face of the cushion layer was less than 5 mm and was within an allowable range (see Table 4). The crystallinity of the release layer of this laminated film was 23.4% (see Table 4). The laminated film could be easily peeled from the circuit exposed film and the CL film (see Table 4).

The temperature of the first roll 230 was set to 35 ° C., the temperature of the touch roll 220 was set to 70 ° C., and the peripheral speed ratio of the second roll 240 to the first roll 230 was set to 0.998, as in Example 12. A laminated film was prepared, and the laminated film was further annealed by being sandwiched between stainless plates having a surface temperature of 130 ° C. and held at a pressure of 10 MPa for 10 minutes, and then the laminated film was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

As a result of the evaluation, the workability of the press set of this laminated film was good (see Table 4). No voids were found in the FPC after pressing (see Table 4). This laminated film was not cracked even after hot pressing (see Table 4). The amount of the adhesive between the circuit-exposed film and the CL film oozed out into the circuit pattern was less than 80 μm, which was superior to the conventional release film (see Table 4). The amount of the stain on the end face of the cushion layer was less than 5 mm and was within an allowable range (see Table 4). The crystallinity of the release layer of this laminated film was 28.7% (see Table 4). The laminated film could be easily peeled from the circuit exposed film and the CL film (see Table 4).
(Comparative Example 1)

As a cushion layer forming blend resin, 80 parts by weight of ethylene-methyl methacrylate copolymer (methyl methacrylate derived unit content: 5% by weight) (Aclift (registered trademark) WD106 manufactured by Sumitomo Chemical Co., Ltd.) A laminated film was produced in the same manner as in Example 1 except that a dry blend of 20 parts by weight of polypropylene (Nobrene FH1016 manufactured by Sumitomo Chemical Co., Ltd.) was used, and the laminated film was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

As a result of the evaluation, the workability of this laminated film press set was good (see Table 5). No voids were found in the FPC after pressing (see Table 5). This laminated film did not crack even after hot pressing (see Table 5). The amount of the adhesive between the circuit-exposed film and the CL film oozed out into the circuit pattern was less than 100 μm, and was within an allowable range (see Table 5). The amount of stain on the end face of the cushion layer was less than 5 mm, and was within an allowable range (see Table 5). However, when the laminated film was peeled from the completed FPC, the cushion layer was peeled from the release layer on the side in contact with the circuit exposed film and the CL film, and the FPC could not be taken out in a good state.
(Comparative Example 2)

As a cushion layer forming blend resin, 40 parts by weight of SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.) and 50 parts by weight of ethylene-methyl methacrylate copolymer (methyl methacrylate derived) Unit content: 5% by weight) (Acrylift (registered trademark) WD106 manufactured by Sumitomo Chemical Co., Ltd.) and 10 parts by weight of polypropylene (Nobrene FH1016 manufactured by Sumitomo Chemical Co., Ltd.) were used. A laminated film was produced in the same manner as in Example 1 except that the laminated film was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

As a result of the evaluation, the workability of the press set of this laminated film was not good (see Table 5). In the FPC after pressing, a very small amount of void was found (see Table 5). This laminated film had micro cracks after heat pressing (see Table 5). The amount of the adhesive between the circuit-exposed film and the CL film oozed out into the circuit pattern was 100 μm or more, which was outside the allowable range (see Table 5). The amount of stain on the end face of the cushion layer was less than 5 mm, and was within an allowable range (see Table 5).
(Comparative Example 3)

As a cushion layer forming blend resin, 70 parts by weight of SPS resin (Zarek (registered trademark) S104 manufactured by Idemitsu Kosan Co., Ltd.) and 20 parts by weight of ethylene-methyl methacrylate copolymer (methyl methacrylate derived) Unit content: 5% by weight) (Acrylift (registered trademark) WD106 manufactured by Sumitomo Chemical Co., Ltd.) and 10 parts by weight of polypropylene (Nobrene FH1016 manufactured by Sumitomo Chemical Co., Ltd.) were used. A laminated film was produced in the same manner as in Example 1 except that the laminated film was evaluated. In addition, the thickness of the release layer of this laminated film was 25 μm on both sides, and the thickness of the cushion layer was 70 μm.

As a result of evaluation, the workability of this laminated film press set was poor (see Table 5). A considerable number of voids were found in the FPC after pressing (see Table 5). This laminated film had relatively large cracks after heat pressing (see Table 5). The amount of the adhesive between the circuit-exposed film and the CL film spilled into the circuit pattern was 100 μm or more, which was outside the allowable range (see Table 5). The amount of stain on the end face of the cushion layer was less than 5 mm, and was within an allowable range (see Table 5).

The laminated film according to the present invention is characterized in that the workability of the press set can be improved, and the rate of non-defective products such as FPC can be increased, and the CL film is adhered to the circuit exposed film by a pressure press. It is particularly useful as a release film that is sometimes used to wrap a coverlay film in order to bring the CL film into close contact with the uneven portion of the circuit pattern.

Other known release films include (1) those used in the production of laminates, (2) those used in the production of advanced composite materials, and (3) those used in the production of sports and leisure goods. The laminated film according to the present invention is also useful as these release films. Note that the release film used in the production of the laminated board is a press-molding process for producing a multilayer printed board, in order to prevent adhesion between the printed board and the separator plate or other printed boards. It is an intervening film. The release film used when manufacturing the advanced composite material product is, for example, a film used when manufacturing various products by curing a prepreg made of glass cloth, carbon fiber or aramid fiber and an epoxy resin. The release film used in the manufacture of sports / leisure goods is, for example, the production of fishing rods, golf club shafts, windsurfing poles, etc. It is a film wound around.

This laminated film is also useful as a release film for adhesive tapes, double-sided tapes, masking tapes, labels, seals, stickers, poultices for skin application, and the like.

This laminated film is also useful as a process film used in the production of printed circuit boards, ceramic electronic parts, thermosetting resin products, decorative boards and the like. In addition, the process film here refers to a metal in the molding process so that metal plates and resins do not adhere to each other when manufacturing printed circuit boards, ceramic electronic parts, thermosetting resin products, decorative boards, etc. It refers to a film that is sandwiched between boards or between resins, and is particularly suitable for use in the production of laminated boards, the production of flexible printed boards, the production of advanced composite materials, and the production of sports and leisure goods.
This laminated film is also useful as a packaging film.

Claims

A first release layer formed from a resin mainly composed of a polystyrene-based resin having a syndiotactic structure;
A cushion layer provided on one side of the first release layer, comprising a polyolefin resin of more than 60 parts by weight and 98 parts by weight or less and a polystyrene resin having a syndiotactic structure of 2 parts by weight or more and less than 40 parts by weight. A laminated film comprising:
2. The laminated film according to claim 1, wherein the polyolefin-based resin contains 3 parts by weight or more and 40 parts by weight or less of a polypropylene resin and 20 parts by weight or more and 95 parts by weight or less of an ethylene-methyl methacrylate copolymer resin. .
The laminated film according to claim 2, wherein the ethylene-methyl methacrylate copolymer resin contains 5 wt% to 14 wt% of units derived from methyl methacrylate.
The first release layer is formed of a resin having a polystyrene resin having a syndiotactic structure as a main component and having a crystallinity measured by differential scanning calorimetry of 14.0% or more and less than 30.0%. The laminated film according to any one of claims 1 to 3.
The laminated film according to any one of claims 1 to 4, further comprising a second release layer formed on a side opposite to the first release layer forming side of the cushion layer.
The said 2nd mold release layer is a laminated film of Claim 5 formed from resin which has as a main component the polystyrene-type resin which has the said syndiotactic structure.
The laminated film according to claim 6, wherein the resin forming the second release layer has a crystallinity measured by a differential scanning calorimetry of 14.0% or more and less than 30.0%.