JP2004191940A - Retroreflection sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retroreflection sheet capable of preventing an abnormality of appearance of a sheet to be generated with time after sticking it to a substrate. <P>SOLUTION: The retroreflection sheet is provided with a plurality of glass balls (2) the lower hemispheres of which metal reflection films (3) are provided, a resin support sheet (4) which holds them and a transparent cover film (1) to be arranged on its surface side, the resin support sheet (4) and the cover film (1) are joined by hot pressing emboss forming from the rear side, the whole of retroreflection sheet is formed and an adhesive layer (11) and a resin peeling film (13) for covering it are included on the rear side. An emboss groove (10) by the hot pressing emboss forming is filled up by a part of the adhesive layer (11), a residual rate of the adhesive layer is within a range of ≥10% to≤50% and drop time of the adhesive layer is within a range of ≥10 hours to ≤ 150 hours. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a retroreflective sheet used for a road sign, a guide sign, a safety guidance sign display board, or other safety signs.

  The retroreflective sheet is widely used as a traffic sign, a guide sign, a warning sign, a regulation sign, and the like, mainly for traffic safety use. The retroreflective sheet has a plurality of retroreflective elements, a resin support sheet, a transparent cover film disposed on the front side of the resin support sheet, and an adhesive on the back side of the resin support sheet. And the retroreflective element is held on at least one of the resin support sheet and the cover film, and the resin support sheet and the cover film are heated from the back side of the resin support sheet. The joining portion is formed by joining by pressure embossing, and the groove of the joining portion is formed on the back surface side of the resin support sheet. A release film is further laminated on the retroreflective sheet. As the release film, a film obtained by applying a release agent such as a silicone compound or a fluorine compound to a release material such as a polyester film, polylaminate, polypropylene, or polyethylene is used. As the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer, a solvent-type pressure-sensitive adhesive, an emulsion-type pressure-sensitive adhesive, a pressure-sensitive adhesive that is cured by an electron beam or ultraviolet light, or the like can be used. Such a retroreflective sheet is a substrate, for example, a metal substrate such as aluminum, iron plate, painted iron plate, stainless steel plate, a plastic substrate such as fiber reinforced plastic (FRP) or rigid PVC, an aluminum plate sandwiching polyethylene or the like. (See Patent Literature 1 and Patent Literature 2), which are pasted on a composite substrate or the like by a pasting device or pasting machine such as a squeegee, hand roll, or mangle roll.

However, when the retroreflective sheet is attached to the substrate, air trapped between the substrate and the retroreflective sheet must be extruded and adhered, or air will be enclosed between the substrate and the retroreflective sheet. It will be in the state that was done. In this case, when the temperature of the substrate rises due to sunlight or the like, the enclosed air expands, causing troubles such as blisters, bubbles, wrinkles, and peeling of the retroreflective sheet. To prevent this, when the retroreflective sheet is attached to the substrate, it is necessary to apply a certain pressure to extrude the air trapped between the substrate and the retroreflective sheet and attach the sheet. Further, when the retroreflective sheet is attached to the substrate when the retroreflective sheet is adhered in a distorted state, the retroreflective sheet is temporally reduced due to the stress remaining inside the retroreflective sheet. There has been a problem that wrinkles, blisters, bubbles, peeling, and the like occur on the sheet.
Japanese Patent No. 3278299 JP-A-2000-329918

  However, at present, no effective countermeasures have been taken against this problem. For example, according to Patent Document 1, as an anti-swelling measure for a retroreflective sheet, the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is a resin obtained by crosslinking a resin having a weight average molecular weight of 500,000 or more by a crosslinking reaction. There has been proposed a retroreflective sheet for a gas generating adherend having a holding force at 10 ° C. of 10 mm / 1000 min or less, and a wetting of the polycarbonate resin plate of 50% or more 30 minutes after the application. However, in practice, even if an adhesive satisfying this condition is used as a measure for preventing blisters or the like of the retroreflective sheet, the above problem has not been sufficiently solved.

  Further, according to Patent Literature 2, it is proposed to use the grooves of the resin support sheet formed at the time of embossing under heat and pressure as an air discharge path. However, when used as a sign outdoors, foreign substances such as water, dust, and dust enter the grooves, reduce the adhesive performance, and cause troubles such as falling off or peeling off the sheet. In order to prevent this trouble, it is necessary to extrude the air in the groove when attaching the retroreflective sheet and embed the pressure-sensitive adhesive layer therein. For this purpose, it is necessary to reduce the cohesive force of the pressure-sensitive adhesive and to make the pressure-sensitive adhesive layer easily enter the groove. On the other hand, when the retroreflective sheet is distorted at the time of attaching, the sheet is subjected to a stress that tends to generate blisters, bubbles, wrinkles, peeling, and the like with time due to the stress remaining on the retroreflective sheet. However, since the cohesive force of the pressure-sensitive adhesive is reduced, the retroreflective sheet cannot cope with this stress and causes cohesive failure of the pressure-sensitive adhesive. As a result, the retroreflective sheet cannot stop the movement due to the action of the residual stress, and blisters, bubbles, wrinkles, peeling, and the like occur in the retroreflective sheet. Under such circumstances, there has been a strong demand in the market for the development of a new retroreflective sheeting that does not generate wrinkles, blisters, bubbles, peeling, and the like after being attached to a substrate.

  The present invention provides a retroreflective sheet capable of preventing appearance abnormalities of the sheet such as blisters, bubbles, wrinkles, and peeling that occur with time after the substrate is attached to solve the conventional problem. The purpose is to.

In order to achieve the above object, the retroreflective sheet of the present invention,
Including a plurality of retroreflective elements, a resin support sheet, a transparent cover film disposed on the front side of the resin support sheet, and an adhesive layer formed on the back side of the resin support sheet The retroreflective element is held on at least one of the resin support sheet and the cover film, and the resin support sheet and the cover film are formed by heat-press embossing from the back side of the resin support sheet. A retroreflective sheeting in which a groove is formed on the back side of the resinous support sheet, wherein the groove is filled with a part of the adhesive layer. A retroreflective sheet wherein the residual ratio of the pressure-sensitive adhesive layer is in the range of 10% or more and 50% or less, and the falling time of the pressure-sensitive adhesive layer is in the range of 10 hours or more and 150 hours or less. A.
The residual ratio (%) = (residual displacement ÷ initial displacement) × 100
The initial displacement was measured using a Yamamoto-type cohesive force measuring device, and the 10 mm × 5 mm retroreflective sheet was subjected to JIS Z 0237 on a mirror-finished flat plate made of SUS304 steel plate specified in JIS G 4305 having a width of 5 mm. Crimping is performed using a specified crimping device, a load of 17 g is applied to both ends of the retroreflective sheet via a thread immediately after the compression, and a load of 200 g for measurement is added to one of the loads, and after 5 minutes, Means the displacement (mm) between the flat plate and the retroreflective sheet that occurs;
The residual displacement means a displacement between the flat plate and the retroreflective sheet, which occurs 10 minutes after the removal of the load of 200 g.
The drop time means the drop time of the retroreflective sheet when a 9.8 N load is applied in a holding force test at 40 ° C. according to the holding force test of JISZ0237.

Next, a method for producing a laminate of a release material having heat resistance and a retroreflective sheet of the present invention comprises a plurality of retroreflective elements, a resin support sheet, and a resin support sheet disposed on the surface side of the resin support sheet. A transparent cover film, wherein the retroreflective element is held by at least one of the resin support sheet and the cover film, and the resin support sheet and the cover film are formed of the resin support sheet. A step of preparing a retroreflective sheet material in which a bonding portion is formed by being joined by heating and pressurizing embossing from the back surface side, and a groove of the bonding portion is formed on the back surface side of the resinous support sheet;
Forming a pressure-sensitive adhesive layer on the heat-resistant release material,
On the back side of the retroreflective sheeting, the heat-resistant release material on which the pressure-sensitive adhesive layer is formed is arranged, and from the heat-resistant release material side, a roll surface of 50 ° C or more and 90 ° C or less. Bonding at a temperature at a linear pressure between the rolls of 100 N / cm or more and 800 N / cm or less to partially fill the adhesive layer in the grooves of the resin-made support sheet. This is a method for producing a laminate of a release material and the retroreflective sheet of the present invention.

  The retroreflective sheet of the present invention is a retroreflective sheet capable of preventing abnormal appearance of the retroreflective sheet that occurs with time after being attached to a substrate.

  The present inventors reduce the air remaining between the retroreflective sheet and the substrate when the retroreflective sheet is attached, thereby reducing the appearance of the retroreflective sheet that occurs over time after attaching to the substrate. It has been found that abnormalities can be prevented. Even if the retroreflective sheet is adhered in a distorted state, the stress remaining on the retroreflective sheet is alleviated by the pressure-sensitive adhesive layer provided on the back side of the resinous support sheet. It has been found that it is possible to prevent the appearance abnormality of the retroreflective sheet from occurring.

  That is, (1) the grooves formed at the time of the heat and pressure embossing are pre-filled with an adhesive layer, and (2) the adhesive layer obtained from the residual displacement and the initial displacement using a Yamamoto-type cohesive force measuring device. By defining the residual ratio of the adhesive layer in a specific range, and (3) by defining the fall time of the pressure-sensitive adhesive layer in a specific range, to reduce the air remaining when the retroreflective sheet is attached, and after attaching. The present inventors have found that the stress remaining in the retroreflective sheet can be reduced, and have completed the present invention.

  Hereinafter, the retroreflective sheet of the present invention will be described in more detail.

  In the retroreflective sheet of the present invention, the thickness of the pressure-sensitive adhesive layer at the portion where the groove on the back side of the resin support sheet is not formed is preferably in the range of 20 μm or more and 110 μm or less, more preferably 30 to 100 μm. It is particularly preferably in the range of 40 to 90 μm. When the thickness is 20 μm or more, the groove of the resin-made support sheet can be filled with a part of the pressure-sensitive adhesive layer, and a thickness sufficient to make the entire pressure-sensitive adhesive layer a uniform thickness. This is because a sufficient adhesive strength can be obtained. When the thickness is 110 μm or less, the adhesive does not protrude, and when the sheet is slit to a fixed size, the adhesive does not protrude from the edge, and the adhesive does not adhere to the slitter teeth. This is because cohesive failure of the resin hardly occurs.

In the retroreflective sheet of the present invention, it is preferable that the filling rate of the groove by the pressure-sensitive adhesive layer is 50% or more.
Filling rate (%) = [(AB) ÷ A] × 100
A is an area of the groove per unit area of the retroreflective sheet,
B means the area of a void formed at the interface between the groove and the pressure-sensitive adhesive layer per unit area of the retroreflective sheet.

  The term “filling” as used herein refers to a state in which the groove is filled with a part of the pressure-sensitive adhesive layer. The filling rate is more preferably 60% or more, more preferably 70% or more. When the filling rate is 50% or more, air between the retroreflective sheet and the substrate can be sufficiently removed when the retroreflective sheet is attached to the substrate.

  In the retroreflective sheet of the present invention, the residual ratio is in a range of 10% to 50%, preferably in a range of 15% to 45%, more preferably in a range of 20% to 40%. The residual ratio indicates the stress relaxation of the pressure-sensitive adhesive layer. When the residual ratio is in the range of 10% or more and 50% or less, the internal stress remaining in the retroreflective sheet at the time of attaching the retroreflective sheet of the present invention is relaxed by the pressure-sensitive adhesive layer and generated with time. This is because appearance abnormalities such as wrinkles, blisters, bubbles, and peeling can be prevented.

  In the retroreflective sheet of the present invention, the falling time is in the range of 10 hours to 150 hours, preferably in the range of 20 hours to 140 hours, and more preferably in the range of 40 hours to 130 hours. The falling time indicates the cohesive force of the pressure-sensitive adhesive layer. If the drop time is 10 hours or more, the cohesive force of the pressure-sensitive adhesive is sufficiently large, so that the adhesive does not lose the contraction stress of the retroreflective sheet, and as a result, the retroreflective sheet does not contract. If the drop time is 150 hours or less, the cohesive force of the pressure-sensitive adhesive does not become too high, so that the retroreflective sheet attached to the substrate remains on the retroreflective sheet before it is put to practical use. This is because the internal stress is alleviated by the pressure-sensitive adhesive layer, and as a result, after the retroreflective sheet is put to practical use, wrinkles, blisters, bubbles, peeling, and the like do not occur in the retroreflective sheet body.

  The retroreflective sheet of the present invention, the residual ratio and the drop time of the pressure-sensitive adhesive layer, the residual ratio and the drop time measured when the retroreflective sheet is put to practical use, or the back surface of the resinous support sheet It is preferable that the residual ratio and the drop time are measured after aging for 7 days in an environment at a temperature of 23 ± 2 ° C. and a relative humidity of 65 ± 5% after forming the adhesive layer on the side.

  Further, in the retroreflective sheet of the present invention, after forming the pressure-sensitive adhesive layer on the back surface side of the resin-made support sheet, the residual ratio and the falling time of the pressure-sensitive adhesive layer are changed to a temperature of 50 ° C. and a relative humidity of 65 ± 5%. It is preferable that the residual rate and the drop time are measured after the aging treatment and then the aging treatment for 10 days in the environment described above.

  The pressure-sensitive adhesive layer of the present invention is preferably formed from a resin such as an acrylic resin or a rubber resin. In particular, as the acrylic resin, a polymer-based acrylic resin containing at least one of an acrylic ester copolymer and an acrylic prepolymer as a main component or a tackifier and a cohesive force in the acrylic resin. A modified acrylic resin to which a monomer to be added is added is preferable.

  Examples of the rubber resin include natural rubber, isoprene rubber, styrene / butadiene block copolymer, styrene / isoprene / styrene block copolymer, butyl rubber, styrene / ethylene / butylene / styrene copolymer, polyisobutylene, and polyvinyl isobutyl. Synthetic rubbers such as ether, chloroprene rubber, and nitrile rubber are exemplified.

  These rubber resins include natural resins such as rosin, modified rosin, rosin and modified rosin derivatives, terpene phenolic resins, polyterpene resins, modified terpene, aliphatic hydrocarbon resins, cyclopentadiene resins, and aromatic resins. -Based petroleum resins, phenolic resins, alkylphenol-acetylene resins, coumarone-indene resins, tackifiers such as vinyltoluene-α-methylstyrene copolymer, various plasticizers, antioxidants, stabilizers, and softening of oils Agents, fillers, stabilizers, pigments, colorants, and the like may be added as necessary. These may be used in combination of two or more as necessary.

  Examples of the acrylic resin include an alkyl group, a hydroxyl group, an epoxy group, an alkoxy group, a phenoxy group, an oxyethylene group, an amino group, an amide group, a carboxyl group, a halogen atom, a phosphoric acid group, a sulfonic acid group, and a urethane group. , A polymer or copolymer of an acrylic vinyl monomer having a phenyl group, a benzyl group, a tetrahydrofurfuryl group, or the like, and a copolymer of an acrylic vinyl monomer with other copolymerizable monomers.

  Examples of the acrylic vinyl monomer having an alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, butyl (meth) acrylate, and hexyl (meth) acrylate. ) Acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isoamyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, dodecyl (meth) acrylate, isobutyl (meth) acrylate, etc. No.

  Examples of the acrylic vinyl monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-chloro-2-hydroxypropyl (meth) acrylate. And the like.

  Examples of the acrylic vinyl monomer having an epoxy group include glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate.

  Examples of the acrylic vinyl monomer having an alkoxy group include methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, and butoxyethyl (meth) acrylate.

  Examples of the acrylic vinyl monomer having a phenoxy group include phenoxyethyl (meth) acrylate.

  Examples of the acrylic vinyl monomer having an oxyethylene group include diethylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, and phenoxypolyethylene glycol (meth) acrylate. Can be

  Examples of the acrylic vinyl monomer having an amino group include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, N-tert-butylaminoethyl (meth) acrylate, and methacryloyloxyethyltrimethylammonium chloride (meth) acrylate. No.

  Examples of the acrylic vinyl monomer having an amide group include (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, and N, N'-methylenebis (meth) acrylamide.

  Examples of the acrylic vinyl monomer having a carboxyl group include acrylic acid, methacrylic acid, 2-methacryloyloxysuccinic acid, 2-methacryloyloxyethylmaleic acid, 2-methacryloyloxyethylphthalic acid, and 2-methacryloyloxyethylhexahydrophthalic acid. Is mentioned.

  Examples of the acrylic vinyl monomer having a halogen atom include trifluoroethyl (meth) acrylate, pentadecafluorooxyethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2,3-dibromopropyl (meth) acrylate and tribromo. Phenyl (meth) acrylate and the like.

  Examples of the acrylic vinyl monomer having a phosphoric acid group include 2-methacryloyloxyethyl diphenyl phosphate (meth) acrylate, trimethacryloyloxyethyl phosphate (meth) acrylate, and triacryloyloxyethyl phosphate (meth) acrylate.

  Examples of the acrylic vinyl monomer having a sulfonic acid group include sodium sulfopropyl (meth) acrylate, sodium 2-sulfoethyl (meth) acrylate, and sodium 2-acrylamido-2-methylpropanesulfonate.

  Examples of the acrylic vinyl monomer having a urethane group include urethane (meth) acrylate.

  Examples of the acrylic vinyl monomer having a phenyl group include phenyl (meth) acrylate, p-tert-butylphenyl (meth) acrylate, and o-biphenyl (meth) acrylate.

  Examples of the acrylic vinyl monomer having a benzyl group include benzyl (meth) acrylate.

  Examples of the acrylic vinyl monomer having a tetrahydrofurfuryl group include tetrahydrofurfuryl (meth) acrylate.

  Examples of other copolymerizable monomers include vinyl monomers having a silane group, styrene, chlorostyrene, α-methylstyrene, vinyltoluene, vinyl chloride, vinyl acetate, vinyl propionate, Veova10 (manufactured by Shell Chemical Company, Chelate compound), acrylonitrile, vinylpyridine and the like.

  Examples of the vinyl monomer having a silane group include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethyl) silane, vinyltriacetylsilane, methacryloyloxypropyltrimethoxysilane, and the like.

  Examples of other copolymerizable monomers include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, and 1,3-butylene. Glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, divinylbenzene, N, N'-methylenebisacrylamide, 1,4-butanediol di (meth) acrylate, 1 , 6-hexanediol di (meth) acrylate and the like can be used. This monomer can be used to the extent that coating suitability is not reduced.

  Further, acrylic resin, as various additives, for example, natural resin such as rosin, modified rosin, rosin and derivatives of modified rosin, polyterpene resin, modified terpene, terpene phenol resin, aliphatic hydrocarbon resin, cyclocarbon resin Pentadiene resin, aromatic petroleum resin, phenolic resin, alkylphenol-acetylene resin, cumarone-indene resin, tackifiers such as vinyltoluene-α-methylstyrene copolymer, various plasticizers, anti-aging agents, stable Agents, softeners such as oils, fillers, coloring agents, pigments, and the like can be added as necessary. These may be used in combination of two or more as necessary.

  The acrylic resin is produced by polymerizing by an arbitrary method among conventionally known methods such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method.

  In addition, the monomer concentration at the time of polymerization is usually 30 to 70% by weight, preferably about 40 to 60% by weight.

  Further, a thickener, a wetting agent, a leveling agent, an antifoaming agent and the like may be appropriately added to the resin constituting the pressure-sensitive adhesive layer. When a crosslinked acrylic copolymer having a functional group is used as the acrylic resin, it is preferable to add a curing agent having a reactive functional group that reacts with the functional group. When an acrylic copolymer that is not a cross-linkable type is used as the acrylic resin, a curing agent may be appropriately added. When a curing agent is added, it is preferable that after forming an adhesive layer in the groove of the retroreflective sheet, one having a residual ratio and a falling speed falling within the range of the present invention is selected. For example, the retroreflective sheet of the present invention is preferably a retroreflective sheet in which the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a crosslinked acrylic copolymer and a curing agent.

  When a curing agent is added to the cross-linkable acrylic copolymer having a functional group, the type of the functional group and the substituent in the acrylic resin and the combination ratio with the curing agent are changed to change the mixing ratio. After aging treatment for 7 days in an environment of 23 ± 2 ° C. and 65 ± 5% of relative humidity, it is preferable to select a compound having a residual ratio and a falling rate falling within the range of the present invention. .

  In the retroreflective sheet of the present invention, the pressure-sensitive adhesive layer is, for example, coated with a solution of the resin on a heat-resistant release material, and then heated and dried at 70 ° C. for 1 minute and at 100 ° C. for 2 minutes. May be formed.

Examples of the curing agent include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl-tris (2-hydroxyethyl) isocyanurate, glycerol polyglycidyl ether, and triglyceride polyglycidyl ether. Methylol propane polyglycidyl ether, resorcin diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, bisphenol-S-diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol Diglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid Epoxy curing agents such as glycidyl ether, toluylene diisocyanate, 2,4-toluylene diisocyanate dimer, naphthylene-1,5-diisocyanate, o-toluylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate, tris (p-isocyanate Phenyl) thiophosphite, polymethylene polyphenylisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, isocyanate-based curing agents such as polyisocyanate prepolymers, melamine, urea, acetoguanamine, benzoguanamine, and steloguanamine Alternatively, various amino group-containing compounds such as spiroguanamine and form Aldehyde, paraformaldehyde, and various aldehyde compounds such as acetaldehyde or glyoxal, aminoplast type curing agent such as a condensation product obtained by reacting in a conventional ^{manner, Mg 2+, Ca 2+, Zn} 2+, Al 3 ^And an ionic curing agent containing ⁺ or the like (eg, zinc acetate, magnesium acetate, calcium acetate, etc.).

  In addition, the residual ratio and the drop time of the pressure-sensitive adhesive layer of the retroreflective sheeting of the present invention are, for example, by appropriately setting the type and the mixing ratio of the resin and the curing agent as the material of the pressure-sensitive adhesive layer, Can be adjusted.

  The retroreflective sheet laminate of the present invention includes the retroreflective sheet of the present invention and a resin release film, wherein the resin release film is laminated on the adhesive layer. It is a laminate.

  In the retroreflective sheet laminate of the present invention, it is preferable that the resin release film is a flexible resin film having a Young's modulus of 50 MPa or more and 2000 MPa or less. The Young's modulus is more preferably in a range from 100 MPa to 1500 MPa, and further preferably in a range from 150 MPa to 1000 MPa.

  In the retroreflective sheet laminate of the present invention, the flexible resin film is preferably an unstretched polypropylene (PP) film or a low density polyethylene (LDPE) film.

  In the retroreflective sheet laminate of the present invention, the thickness of the unstretched polypropylene film is preferably in a range from 20 μm to 150 μm. The thickness is more preferably in a range from 30 μm to 130 μm, and further preferably in a range from 40 μm to 100 μm.

  In the retroreflective sheet laminate of the present invention, the thickness of the low-density polyethylene film is preferably in the range of 20 μm or more and 200 μm or less. The thickness is more preferably in a range from 40 μm to 150 μm, and further preferably in a range from 60 μm to 100 μm.

  As described above, the method for producing a laminate of a release material having heat resistance and the retroreflective sheet of the present invention includes a plurality of retroreflective elements, a resin support sheet, and a surface of the resin support sheet. A transparent cover film disposed on the side, the retroreflective element is held on at least one of the resin support sheet and the cover film, and the resin support sheet and the cover film are made of the resin. A raw sheet of a retroreflective sheet is prepared in which a bonding portion is formed by being joined by heat and pressure embossing from the back surface side of the support sheet, and a groove of the bonding portion is formed on the back surface side of the resinous support sheet. A step of forming the pressure-sensitive adhesive layer on the heat-resistant release material, the heat-resistant release in which the pressure-sensitive adhesive layer is formed on the back surface of the retroreflective sheeting sheet. And the resin support sheet is bonded from the heat-resistant release material side at a roll surface temperature of 50 ° C. or more and 90 ° C. or less and a line pressure of 100 N / cm or more and 800 N / cm or less. Filling the groove with a part of the pressure-sensitive adhesive layer.

  The production method preferably further includes a step of subjecting the pressure-sensitive adhesive layer to an aging treatment under an environment of 23 ± 2 ° C. and a relative humidity of 65 ± 5% for 7 days.

  In the manufacturing method, the heat-resistant release material is preferably paper, synthetic resin laminated paper, a polypropylene film, or a polyester film. In this case, it is preferable that the thickness of the paper is in the range of 20 μm or more and 200 μm or less. The thickness is more preferably in a range from 40 μm to 170 μm, and still more preferably in a range from 60 μm to 150 μm. In this case, the thickness of the synthetic resin laminated paper is preferably in a range of 30 μm or more and 220 μm or less. The thickness is more preferably in a range from 50 μm to 200 μm, and further preferably in a range from 70 μm to 180 μm. In this case, the thickness of the polypropylene film is preferably in the range of 15 μm or more and 250 μm or less. The thickness is more preferably in a range from 30 μm to 230 μm, and further preferably in a range from 50 μm to 200 μm. In this case, the thickness of the polyester film is preferably in a range of 15 μm or more and 250 μm or less. The thickness is more preferably in a range from 30 μm to 220 μm, and further preferably in a range from 50 μm to 190 μm.

  The retroreflective sheet laminate of the present invention as an example of a product shipping form includes, for example, the heat-resistant sheet laminate produced by the above-described manufacturing method, which is a laminate of the retroreflective sheet of the present invention and a heat-resistant release material. After peeling off the release material having the above, it can be manufactured by sticking a resin release film on the surface of the adhesive layer of the retroreflective sheet. In this case, for example, after forming the pressure-sensitive adhesive layer, the heat-resistant release material is peeled off, and after being replaced with the resin-made release film, at 23 ± 2 ° C. and a relative humidity of 65 ± 5%. The aging treatment may be performed in an environment for 7 days. Alternatively, after the pressure-sensitive adhesive layer is formed and the aging treatment is performed for 7 days, the heat-resistant release material may be peeled off and replaced with the resin release film. Alternatively, the aging treatment for 7 days may be performed separately before and after the application to the resin release film. In particular, it is preferable to perform an aging treatment for 7 days in an environment of 23 ± 2 ° C. and 65 ± 5% of relative humidity after replacing with the resin release film.

  Hereinafter, an example of the method for manufacturing the retroreflective sheet of the present invention will be specifically described with reference to the drawings. 1 to 7 show steps of an example of a method for manufacturing a retroreflective sheet of the present invention.

  As the retroreflective element, a transparent sphere having a reflecting mirror in a hemispherical portion, a cube corner type retroreflective element, or the like can be used. Here, a case where a transparent sphere having a reflecting mirror in a hemispherical portion is used will be exemplified. Further, as described above, the retroreflective element is held on at least one of the resin support sheet and the cover film, but here, the transparent sphere, the hemispherical side covered with the reflecting mirror, the An example of a capsule lens type retroreflective sheeting when held so as to be embedded in a resin support sheet will be described. However, in the case of a cube corner type retroreflective element, it is held by a cover film.

  First, a reflecting mirror is formed on a hemispherical portion of the transparent sphere. As shown in FIG. 1, a plurality of transparent glass spheres 2 as the transparent spheres are embedded on the surface of a polyethylene glass sphere temporary fixing layer 7 laminated on a polyester film 8 as a first film. For embedding, the laminated body of the glass ball temporary fixing layer 7 and the polyester film 8 is heated to soften the polyethylene, and the glass spheres 2 are submerged in the glass ball temporary fixing layer 7. The glass sphere 2 is an example of the transparent sphere as described above. Examples of the transparent sphere include glass spheres and transparent resin beads, and among them, glass spheres are preferable. The particle diameter of the transparent sphere is, for example, about 5 μm to 300 μm, preferably about 20 μm to 90 μm, and more preferably 40 μm to 80 μm. The refractive index of the transparent sphere is, for example, about 1.8 to 2.1, preferably about 1.9 to 1.95, and more preferably 1.92 to 1.93.

  Next, a metal reflective film 3 is formed on the hemispherical surface of the glass sphere 2 exposed from the surface of the glass sphere temporary fixing layer 7 by a vapor deposition method. Since this vapor deposition is performed on the entire surface of the glass ball temporary fixing layer 7, the metal reflection film 3 is formed not only on the glass ball 2 but also on the surface of the glass ball fixing layer 7. Examples of the material of the metal reflection film 3 include aluminum, gold, silver, copper, nickel, chromium, tin, alloys containing these metals, titanium oxide, titanium nitride, and other materials having excellent light reflectance. Aluminum is preferred.

As the retroreflective sheet of the present invention, there is a retroreflective sheet having the following two types of structures.
(A) A type having a primer layer 5 on the back surface of a resin support sheet 4 (see FIG. 2).
(B) A type in which the primer layer 5 is not provided on the back surface of the resin support sheet 4.

  In the case of the above (A), the pressure-sensitive adhesive layer is laminated on the back surface of the primer layer 5 and in the case of (B), the pressure-sensitive adhesive layer is laminated on the back surface of the resin support sheet 4. In order to transfer the glass spheres 2 of the glass sphere temporary fixing layer 7 to the resin support sheet 4, a polymer or a low-molecular plasticizer may be used for the resin support sheet 4 in some cases. These plasticizers and the like migrate over time to the interface between the pressure-sensitive adhesive layer and the resinous support sheet 4 or to the pressure-sensitive adhesive layer, and reduce the pressure-sensitive adhesive performance of the pressure-sensitive adhesive layer. That is, a decrease in the interfacial adhesive strength between the pressure-sensitive adhesive layer and the resin-made support sheet 4 and a decrease in the adhesive performance of the pressure-sensitive adhesive layer to the substrate occur. The primer layer 5 can be used to solve this problem, that is, to prevent migration of a plasticizer or the like from the resin support sheet 4 to the pressure-sensitive adhesive layer.

  As the resin forming the resin support sheet 4, a thermoplastic resin or a thermosetting resin can be used. Examples of the thermosetting resin include a resin having a functional group, for example, a self-crosslinking resin having one or more functional groups or a resin having one or more functional groups, and a functional group capable of reacting with these functional groups. Combinations with group-containing curing agents are preferred. In addition, a silane coupling agent, a relatively low-molecular resin having a polar group, or the like may be added to the thermosetting resin in order to improve the spreadability and the fixability of the glass sphere. In the resin constituting the resin support sheet 4, the total weight of the resin having the functional group and the curing agent is 50%, preferably more than 70% by weight of the resin constituting the resin support sheet 4. Is preferred.

  Examples of the resin having the functional group include acrylic resins, fluororesins, vinyl copolymers such as styrene copolymers, and polycondensation copolymers such as polyester resins and polyurethane resins. The functional group refers to a reactive functional group or a self-crosslinkable functional group that participates in the reaction with the curing agent component. Examples of the reactive functional group that participates in the reaction with the curing agent component include a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group, an amino group, an acid amide group, and an unsaturated double bond. Examples of the self-crosslinkable functional group include a hydrolyzable silyl group, an N-methylolacrylamide group, an alkyl etherified N-methylolacrylamide group, and an unsaturated double bond.

  As the curing agent, when the reactive functional group is a group having a so-called active hydrogen atom such as a hydroxyl group, a carboxyl group, an amino group or an acid amide group, an isocyanate-based curing agent and an aminoplast-based curing agent are used. , A polyepoxy compound or an acid anhydride. When the reactive functional group is an epoxy group or the like, examples of the curing agent include polyamines and polybasic acids. When the reactive functional group is an isocyanate group, examples of the curing agent include various polyhydroxy compounds such as glycols.

  When the reactive functional group is a so-called self-crosslinkable functional group such as a hydrolyzable silyl group, a crosslinking accelerator may be further used. The crosslinking accelerator is a catalyst for hydrolysis or condensation of the hydrolyzable silyl group. Examples of the crosslinking accelerator include various acidic compounds such as sulfuric acid, hydrochloric acid and phosphoric acid, various amine compounds such as monomethylamine and triethylamine, di-n-butyltin dilaurate, di-n-butyltin diacetate and diamine. Various organic tin compounds such as -n-butyltin dioctate can be used.

  Examples of the resin forming the primer layer 5 include the resin having the functional group, which forms the support sheet 4 made of resin, or the resin and the curing agent having the functional group which reacts with the functional group of the resin. And a hardening agent selected from the following. The resin used for the primer layer 5 is preferably one having excellent interlayer adhesion with the resin support sheet 4.

  The primer layer 5 is obtained by, for example, applying a solution of a resin forming the primer layer on a separately prepared polyester film 6 as a second film, and drying the solution using, for example, a hot-air dryer. be able to. The second film is an example of the support in the preferred production method of the present invention. The thickness of the primer layer 5 after drying is, for example, 3 μm to 100 μm, and preferably 6 μm to 50 μm. When the thickness is 3 μm or more, the effect of preventing migration of the plasticizer or the like is enhanced, which is preferable. When the thickness is 100 μm or less, workability such as attaching a retroreflective sheet is improved, which is preferable.

  Next, a resin support sheet 4 is formed on the surface of the primer layer 5 (FIG. 2). As the resin forming the resin support sheet 4, any of the resin having the functional group and the resin having no functional group can be used, but the resin having the functional group is preferable.

  The resin support sheet 4 can be obtained, for example, by applying a resin solution forming the resin support sheet on the primer layer 5 and drying the solution using, for example, a hot-air drier ( (See FIG. 2). The thickness of the resin support sheet 4 after drying is, for example, 10 μm to 300 μm, and preferably about 30 μm to 100 μm.

  The retroreflective sheet of the type (B) having no primer layer 5 can be obtained by omitting the step of preparing a primer layer in the above-described method for producing a retroreflective sheet.

  Next, as shown in FIG. 3, the laminate of the polyester film 6, the primer layer 5, and the resin support sheet 4 is made to conform to the surface of the glass ball temporary fixing layer 7. The resin support sheet 4 is brought into contact with the surface of the glass sphere 2 on which the metal reflection film 3 of the glass sphere temporary fixing layer 7 is deposited.

  Then, as shown in FIG. 4, the laminate is pressed against the surface of the glass ball temporary fixing layer 7. The pressing is performed such that the hemispherical surface of the glass sphere 2 on which the metal reflective film 3 is deposited is buried in the resin support sheet 4. At this time, a coupling agent or the like can be further added to the resin support sheet 4 in order to improve the fixing force of the resin support sheet 4 to the glass balls 2.

  Then, as shown in FIG. 5, the glass ball temporary fixing layer 7 is peeled off together with the polyester film 8 from the surface of the resin support sheet 4. At this time, as shown in FIG. 5, the glass spheres 2 remain in the resin support sheet 4 and the hemispherical surface on which the metal reflection film 3 is deposited is held by the resin support sheet 4 in a buried state. Further, the metal reflection film 3 provided on a portion other than the hemisphere of the glass sphere 2 exposed from the surface of the glass sphere temporary fixing layer 7 remains on the surface of the glass sphere temporary fixing layer 7 as it is.

  Thereafter, when the primer layer 5 and / or the resin-made support sheet 4 contains a curing agent (for example, an isocyanate curing agent) that cures at room temperature, an aging treatment is performed in a temperature environment of 30 to 40 ° C. It is preferable that the primer layer 5 and / or the resin support sheet 4 be cured. After that, it is to eliminate the dispersion of the performance of the joint formed at the time of the heat-press embossing and to stabilize the self-standing form thereafter. Further, a heat treatment step at 120 to 150 ° C. may be performed in order to improve the adhesion between the glass ball 2 and the resin support sheet 4.

  Next, the surface of the resin support sheet 4 holding the glass balls 2 in the state shown in FIG. 6 is covered with the transparent cover film 1. The cover film 1 is made of an unstretched acrylic film, polyester resin, acrylic resin, alkyd resin, urethane resin, vinyl chloride resin, polycarbonate resin, fluororesin, acrylic silicone resin, etc. A good film can be used. Among them, an unstretched acrylic film is preferable.

  As the cover film 1, other than a film manufactured by a casting method, that is, a film manufactured by a well-known technique such as an extrusion method and a calender method can be used. Such a film is inevitably stretched by at least 10 to 20% in the flow direction of the film at the time of production in the production method, but is preferably in a non-stretched state as much as possible.

  When a thermoplastic resin is used as the cover film 1, thermal fusion between the resin support sheet 4 and the cover film 1 can be favorably performed, which is preferable.

  When the cover film 1 is made of a resin having low heat-sealing suitability, for example, a part of a thermosetting resin, a fluorine-based resin, or a silicone-based resin, a laminate of the resin having excellent heat-sealing suitability and the resin is used. Can be used as the cover film 1.

  When the cover film 1 is formed, it may be formed by using an ultraviolet absorber or an antioxidant in combination.

  From the polyester film 6 side of the resin support sheet 4 on the surface of which the cover film 1 is disposed, heat compression bonding is performed with the embossed roll 9 with a handle (see FIG. 7). This thermocompression bonding is preferably performed by passing through a heating roll. The surface temperature of the roll is, for example, 150 to 240 ° C, and preferably 170 to 220 ° C. When the surface temperature is 150 ° C. or higher, heat-press bonding is possible, the resin-made support sheet 4 and the cover film 1 can be bonded, and the resin-made support sheet 4 can maintain a self-standing form for a long period of time, which is preferable. . When the surface temperature is 240 ° C. or lower, the polyester film 6 as the second film is not dissolved, and the workability of thermocompression bonding is improved.

  After the thermocompression embossing, the polyester film 6 is peeled off to obtain an original retroreflective sheet. An embossed groove 10 is formed on the back surface side of the resin support sheet 4 by the thermocompression bonding. The groove has a size of, for example, a width of 200 to 800 μm and a depth of 100 to 150 μm.

  As the retroreflective sheet raw material constituting the retroreflective sheet of the present invention, in addition to the capsule lens type retroreflective sheet raw material, a retroreflective sheet raw material manufactured by various known methods may be used. Can be.

  For example, as shown in FIG. 10, a capsule cube corner type retroreflective sheet which is heat-molded can be used as a raw material of the retroreflective sheet. That is, a capsule cube corner type recursive member including a cover film 1, a cube corner type retroreflective element 14 arranged on the back surface of the cover film 1, a resin support sheet 4, and a joint formed by heat molding. A reflective sheet can also be used.

  Next, an adhesive layer is formed on a separately prepared heat-resistant release material. The pressure-sensitive adhesive is as described above. Known and commonly used hard release papers can be used as the release material. For example, a base material having a filler layer provided on a base paper such as glassine paper, clay-coated paper, kraft paper, or high-quality paper having a thickness of 30 to 100 μm, a poly-laminate paper having a thickness of 50 to 200 μm (polyethylene, such as kraft paper or high-quality paper, Manufactured by laminating a synthetic resin such as polypropylene), or 15 to 250 μm thick polypropylene, a film such as polyethylene terephthalate, an emulsion type, a solvent type or a non-solvent type silicone resin or a fluororesin, etc. A material in which a release agent layer is formed by heat curing, electron beam or ultraviolet curing, or the like can be used as appropriate. Among the release agents, a silicone resin is particularly preferable. As a method for forming the release agent layer, a known and commonly used method, for example, a comma doctor, a bar coater, a gravure coater, a reverse roll coater or the like is appropriately used.

  The formation of the pressure-sensitive adhesive layer 11 on the heat-resistant release material can be performed as follows. For example, the pressure-sensitive adhesive solution may be applied onto the release agent layer surface of a release paper 12 as an example of the release material, and dried as necessary to obtain the pressure-sensitive adhesive layer 11.

  In addition, as an apparatus for applying an adhesive, for example, a reverse roll coater, a knife coater, a bar coater, a slot die coater, an air knife coater, a reverse gravure coater, a vario gravure coater and the like can be mentioned. The coating amount of the pressure-sensitive adhesive solution is adjusted so that the thickness of the pressure-sensitive adhesive layer obtained after drying is, for example, in the range of 20 μm to 110 μm.

  The pressure-sensitive adhesive solution contains the pressure-sensitive adhesive and, if necessary, the additive. As a solvent for the pressure-sensitive adhesive solution, a common organic solvent, for example, toluene, benzene, butyl acetate, ethyl acetate, methyl isobutyl ketone, methyl ethyl ketone, various alcohols and the like can be used.

  Next, a laminate of the release material and the pressure-sensitive adhesive layer 11 is bonded to the original retroreflective film. As this bonding method, a generally known method, for example, using a bonding roll, the pressure-sensitive adhesive layer 11 of this laminate and the primer layer 5 of the raw material of the retroreflective sheet (if the primer layer 5 is omitted, And the resin support sheet 4) so as to face each other (see FIG. 8).

  At this time, if the roll temperature of the bonding roll on the release paper side is set to, for example, 50 ° C to 90 ° C, preferably 55 ° C to 85 ° C, and more preferably 60 ° C to 80 ° C, It is possible to sufficiently fill with a part of the agent layer. When the roll temperature is 90 ° C. or lower, the cover film 1 of the original retroreflective sheet is less susceptible to damage such as shrinkage, which is preferable. Further, when the roll temperature is 50 ° C. or higher, heating is effectively performed, which is preferable. The bonding pressure at this time is, for example, 100 N / cm to 800 N / cm, preferably 150 N / cm to 750 N / cm, and more preferably 200 N / cm to 700 N / cm. When the laminating pressure is 100 N / cm or more, the groove can be sufficiently filled with the adhesive, and when the laminating pressure is 800 N / cm or less, the retroreflective sheet raw material is not damaged by pressing pressure or the like. ,preferable.

  Next, the release paper 12 is peeled off. In general, many heat-resistant release materials such as the release paper 12 are inferior in flexibility. In that case, it is preferable to peel off the heat-resistant release material and affix the resin release film 13 on the pressure-sensitive adhesive layer to obtain the retroreflective film laminate of the present invention (see FIG. 9). . The resin-made release film is excellent in flexibility, and after winding the retroreflective film laminate to a long length, even when unwound, it is difficult to form a curl on the retroreflective film laminate. is there. Therefore, when printing or the like is performed on the retroreflective film laminate, a phenomenon (tunnel phenomenon) between the retroreflective film and the resin release film that partially expands and peels like a tunnel. Generation can be suppressed, which is preferable. The resin release film having excellent flexibility is as described above.

  Alternatively, the pressure-sensitive adhesive layer 11 may be directly formed on the primer layer 5 of the original retroreflective sheeting, and the resin release film 13 may be disposed on the pressure-sensitive adhesive layer 11. For example, a pressure-sensitive adhesive solution or a pressure-sensitive adhesive not diluted with a solution is applied onto a primer layer 5 of the raw material of the retroreflective sheeting (in a case where the primer layer 5 is omitted, a resin support sheet 4), and dried if necessary. Thus, an adhesive layer 11 is obtained. The pressure-sensitive adhesive used in this case is preferably of the type that cures with an electron beam, ultraviolet light, or the like, which does not require heat drying, since the heat resistance of the retroreflective sheet raw material is inferior. In this case, after irradiating the adhesive layer with the electron beam or ultraviolet rays to the adhesive solution or the adhesive layer not diluted with the solution to cure the adhesive, a resin release film 13 is applied to the adhesive layer 11. Just stick them together.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following, “parts” indicates “parts by weight”. “%” Indicates “% by weight”.

  First, an example of adjusting a resin necessary for producing a retroreflective sheet will be described.

Preparation Example of Resin Having Functional Group and Resin Having No Functional Group Preparation of Solution (A-1) of Hydroxy Group-Containing Acrylic Resin 700 parts of toluene and 300 parts of n-butanol were charged into a reactor equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas inlet. , And the temperature was raised to 80 ° C. There, a mixture consisting of 500 parts of methyl methacrylate, 400 parts of ethyl methacrylate, 100 parts of 2-hydroxyethyl methacrylate, 8 parts of azobisisobutyronitrile and 5 parts of tert-butyl peroxyoctoate (TBPO). Was added dropwise over 4 hours. After maintaining at the same temperature for 10 hours, a solution of a hydroxyl group-containing acrylic resin (A-1) [nonvolatile content = 50%; weight average molecular weight = 32,000; hydroxyl value = 43 mgKOH / g solid content; calculated from hydroxyl value Functional group equivalent = 1,300 (solid content)].

2. Preparation of Solution (A'-1) of Acrylic Resin Having No Functional Group In the preparation example of the acrylic resin solution (A-1), "500 parts of methyl methacrylate, 400 parts of ethyl methacrylate, 100 parts of 2-hydroxyethyl methacrylate" Is changed to "700 parts of methyl methacrylate and 300 parts of ethyl acrylate", "8 parts" of azobisisobutyronitrile is changed to 5 parts, and "5 parts" of t-butyl peroxyoctoate (TBPO) is changed. Part "was changed to 2 parts, and in the same manner as in the preparation example of the acrylic resin solution (A-1), an acrylic resin solution (A'-1) containing no functional group [nonvolatile content = 50%; weight Average molecular weight = 81,000].

3. Preparation Example of Hydroxyl Group-Containing Acrylic Resin Solution (A-2) In a device similar to the preparation example of the above (A-1), water: 1,000 parts, styrene: 200 parts, n-butyl acrylate: 200 parts, -Hydroxyethyl methacrylate: 100 parts, 1% aqueous solution of polyvinyl alcohol (average degree of polymerization: 100): 20 parts, and azobisisobutyronitrile: 2 parts were charged. The mixture was stirred to keep the system in suspension, then the temperature of the system was raised to 80 ° C. and reacted at the same temperature for 4 hours.

  Next, the suspension after the reaction was washed with water, drained and dried to obtain a resin in the form of beads. Further, 400 parts of this resin was dissolved in 1,600 parts of toluene, and a solution of a hydroxyl group-containing acrylic resin (A-2) [nonvolatile content = 20%; weight average molecular weight = 250,000; hydroxyl value = 86 mgKOH / g solid Min; functional group equivalent calculated from hydroxyl value = 652 (solid content)].

4. Preparation Example of Hydroxyl-Containing Fluororesin Solution (A-3) 1,000 parts of xylene and 10 parts of bis (1,2,2,6,6-pentane) were placed in a stainless steel autoclave having an inner volume of 5,000 ml. Methyl piperidinyl) sebacate, tert-butyl peroxypivalate, 200 parts of cyclohexyl vinyl ether, 230 parts of ethyl vinyl ether and 70 parts of 4-hydroxybutyl vinyl ether were charged, and the air in the autoclave was replaced by blowing nitrogen gas. did.

  Further, 500 parts of liquefied and collected hexafluoropropylene was charged into the autoclave. After sealing the autoclave, the autoclave was kept warm at 60 ° C. and reacted for 15 hours to obtain a fluororesin solution (A-3) [nonvolatile content = 50%; weight average molecular weight = 42,500; Value = 67 mg KOH / g solid content; functional group equivalent calculated from hydroxyl value = 840 (solid content)].

5. Preparation Example of Hydroxyl-Containing Polyester Resin Solution (A-4) In a reactor equipped with a stirrer, thermometer, rectification tower and nitrogen gas inlet, 130 parts of ethylene glycol, 114 parts of neopentyl glycol, 1,6- 100 parts of hexanediol, 48 parts of trimethylolpropane, 720 parts of isophthalic acid, and 0.5 part of dibutyltin oxide were charged. The temperature of the reactor system was raised to 220 ° C., maintained at the same temperature for 3 hours, further raised to 240 ° C., and subjected to a dehydration condensation reaction at the same temperature for 6 hours. Then, the temperature of the system was lowered to 130 ° C., 1,000 parts of xylene was added to the reactor, and a polyester resin solution (A-4) [nonvolatile content = 50%; weight average molecular weight = 47,000; hydroxyl value = 10 mg KOH / g solid content; functional group equivalent calculated from hydroxyl value = 5,650 (solid content)].

In the examples of the present invention, the following various measuring methods were used.
(1) Yamamoto-type cohesive force test The Yamamoto-type cohesive force measuring device shown in FIG. 12 was used. This apparatus has a size of 520 mm in width, 345 mm in height, and 140 mm in depth. A thread was applied to a load pulley 24 and a side pulley 25 via a thread, and loads 22 and 23 were applied to both ends. A jig 32 having a core 30 of an electric micrometer 31 was placed on the adherend 21 and the retroreflective sheet 26. 27 is a fastening screw, 28 is a micrometer, 29 is a coil, 34 is a display, and 35 is a core holding block. FIG. 13 is a schematic perspective view for referring to the method of connecting the retroreflective sheet 26 and the yarn of the measuring device of FIG. 36 is a pressing roller, and 37 is a thread.

  Using a Yamamoto-type cohesive force measuring device, a test piece of the retroreflective sheet 26 cut to a width of 10 mm is attached to a mirror-finished flat plate of a SUS304 steel sheet specified in JIS G4305 having a width of 5 mm so that the test piece of 10 mm x 5 mm is in contact with the plate. Was. Attachment conditions at this time were those of an automatic type specified in 10.2.4 of JISZ0237, and three reciprocations were performed with a roller 36 having a mass of 2 kg at a pressure bonding speed of 5 mm / sec. Immediately after the pressure bonding, a load of 17 g (load 22, 23) was applied to both ends of the test piece via a thread, and then a load of 200 g was applied to the load 22 to measure a displacement (initial displacement) after 5 minutes. A load for measurement was applied, and after 5 minutes, the above-mentioned load of 200 g was removed, and a displacement (residual displacement) remaining 10 minutes after that point was measured, and (residual displacement ÷ initial displacement) × 100 = residual rate (% ) To determine the residual ratio. The measurement conditions are a temperature of 23 ± 2 ° C. and a relative humidity of 65 ± 5%.

(2) Shear holding force test The holding force test was performed based on the holding force test of JIS Z0237. Specifically, SUS304 stainless steel plate was used as the adherend, and the process was performed as follows. The retroreflective sheet was pressed against a stainless steel plate by reciprocating a 2 kg rubber roller three times in an atmosphere at a temperature of 23 ± 2 ° C. and a relative humidity of 65 ± 5%. The attachment area is 25 mm × 25 mm. After standing for 25 minutes, the stainless steel sheet to which the retroreflective sheet was attached was suspended vertically in a holding force tester set at 40 ° C., and left for 1 hour. After one hour, a load of 9.8 N was applied to the retroreflective sheet (suspended). Therefore, the load was 1.568 N / cm ² . Then, a time (fall time) from when the weight was applied to when the retroreflective sheet fell from the stainless steel plate was measured. When the drop time was 24 hours or more, the shift length after 24 hours was also measured.

  A plurality of glass spheres [particle diameter = 45 to 80 μm, refractive index = 1.92 to 1.93] were formed on the surface of a 25 μm-thick polyethylene glass sphere temporary fixing layer laminated on a polyester film (first film). ] (Retroreflective element) was embedded so that about 25 to 35% of its particle size sinks into the glass ball temporary fixing layer. That is, the glass ball temporary fixing layer and the polyester film were heated and softened, and the above-mentioned glass ball was embedded. Next, aluminum was vapor-deposited on the hemispherical surface of the glass sphere exposed from the surface of the glass sphere temporary fixing layer to form a reflecting mirror.

Next, on a separately prepared polyethylene terephthalate (polyester) film (thickness: 50 μm) (second film), methyl methacrylate (MMA), ethyl acrylate (EA), butyl acrylate (BA), 2-hydroxyethyl methacrylate A mixed solution of 83 parts by weight of a toluene and butyl acetate solution (solid content: 50%) of an acrylic copolymer composed of (2-HEMA) and 17 parts by weight of methyletherified methylolmelamine (60% solids) was applied. After drying with a hot air drier, a primer layer having a thickness of about 20 μm was formed. Subsequently, a compounding solution mainly composed of the above-mentioned hydroxyl group-containing acrylic resin solution (A-1) was applied onto the primer layer, and dried with a hot-air drier to form a resin support sheet having a thickness of about 60 μm. The composition of the solution is shown below.
(1) Hydroxyl group-containing acrylic resin solution (A-1) (solid content: 50%) 100 parts (2) Methyl etherified methylolmelamine (solid content: 60%) 11 parts (3) Rutile-type titanium dioxide 25 parts (4 13) Acrylic resin for dispersing pigment (solid content: 50%) 13 parts (5) Silane coupling agent 1 part Next, the polyester film (second film), The laminate of the primer layer and the resin-made support sheet was arranged so that the resin-made support sheet was in contact with the glass sphere surface of the glass sphere temporary fixing layer. Then, the laminate was pressed against the surface of the glass ball temporary fixing layer. This pressing was performed so that the glass ball reflecting mirror was embedded in the resin support sheet. As a means for this pressing, a heating roll having a roll surface temperature of 170 ° C. was passed through the laminate along the resin support sheet.

  Next, the glass ball temporary fixing layer was peeled off from the surface of the resin support sheet together with the polyester film (first film) to obtain a laminate. Subsequently, the obtained laminate was subjected to a heat treatment at 140 ° C. in order to improve the adhesion between the glass balls and the resin support sheet. Then, a transparent acrylic film [manufactured by Kanekachi Chemical Industry Co., Ltd.] which is uniaxially stretched (substantially unstretched with a stretching ratio of 1.3) on the glass ball side of the resin support sheet in which the hemispheres of the glass spheres are embedded. ] (Cover film) to obtain a laminate. Next, from the polyester film (second film) side, the obtained laminate was heat-formed using a patterned embossing roll having a roll surface temperature of 210 ° C. After the heating and pressurizing embossing, the polyester film (second film) was peeled off to obtain a retroreflective sheet material.

100 parts by weight of an amide group-containing acrylic resin "Alloset 8964" (trade name) (manufactured by Nippon Shokubai Co., Ltd.) to which a high softening point tackifier having a solid content of 47% by weight is added as a resin for the adhesive, 0.2 parts by weight of a modified polyisocyanate resin “Coronate L-55E” (trade name) [manufactured by Nippon Polyurethane Industry Co., Ltd.] was stirred and mixed to prepare an adhesive solution. The pressure-sensitive adhesive solution was applied on a hard release paper “EKR-780” (trade name) (manufactured by Lintec Corporation), and was applied at 70 ° C. for 1 minute and at 100 ° C. for 2 minutes.
It was dried by heating for about 30 minutes to form an adhesive layer having a thickness of about 80 μm. Then, the surface of the primer layer of the retroreflective sheeting and the surface of the pressure-sensitive adhesive layer of the laminate of the release paper and the pressure-sensitive adhesive layer are bonded at a bonding pressure of 450 N / cm and a roll surface temperature of 70 ° C. The groove formed in the primer layer by the heat-press embossing was filled with a part of the pressure-sensitive adhesive layer. Thereafter, the release paper was peeled off, and a flexible polypropylene (PP) release film “Film Binner PP-S-80” (trade name) [manufactured by Fujimori Kogyo Co., Ltd., thickness 80 μm, Young's modulus 800 MPa] (made of resin) (Release film) to obtain a retroreflective sheet laminate. The obtained retroreflective sheet laminate was aged for 7 days at 23 ± 2 ° C. and 65 ± 5% relative humidity.

The raw material of the retroreflective sheet was obtained in the same manner as in Example 1 except that the composition of the compound solution for the resin support sheet was changed as follows, and the heat treatment after embedding the glass spheres in the resin support sheet was omitted. Was prepared.
(1) 100 parts of a hydroxyl group-containing acrylic resin solution (A-2) (solid content: 20%) (2) 6.0 parts of methyl etherified methylolmelamine (solid content: 60%) (3) 10 parts of rutile type titanium dioxide (4) 5 parts of an acrylic resin for dispersing a pigment (solid content: 50%) (2) 2 parts of a polyester plasticizer Next, as an adhesive resin, an acrylate copolymer resin having a solid content of 58% by weight "SK Dyne 1576 "(trade name) [manufactured by Soken Chemical Co., Ltd.] and 100 parts by weight of epoxy curing agent" E-05C "(trade name) [manufactured by Soken Chemical Co., Ltd.] 5.1 parts by weight. An adhesive layer was formed in the same manner as in Example 1 to obtain a retroreflective sheet laminate. Thereafter, aging was performed under the same conditions as in Example 1.

After omitting the formation of the primer layer, changing the composition of the compounding solution for the resin support sheet to the following, changing the thickness of the resin support sheet from 60 μm to 80 μm, and embedding the glass balls in the resin support sheet. After the heat treatment at 140 ° C., an original retroreflective sheet was obtained in the same manner as in Example 1 except that a one-month aging step at 30 ° C. was newly added.
(1) Polyester resin (A-4) (solid content: 50%) 100 parts (2) HMDI-based isocyanurate (solid content: 75%, NCO: 15%) 2.5 parts (3) Rutile type titanium dioxide 25 Part (4) Acrylic resin for pigment dispersion (solid content: 50%) 12 parts Next, 0.25 part of "Coronate L-55E" (trade name) (manufactured by Nippon Polyurethane Industry Co., Ltd.) is used as a curing agent. Except for the above, an adhesive layer was formed in the same manner as in Example 1 to obtain a retroreflective sheet laminate. Thereafter, aging was performed under the same conditions as in Example 1.

(Example of using uncured resin sheet as resin support sheet)
Except for omitting the formation of the primer layer, changing the composition of the compounding solution for the resinous support sheet to the following, and changing the thickness of the resinous support sheet from 60 μm to 80 μm, the same as in Example 1 except that A reflection sheet material was obtained.
(1) Acrylic resin solution (A'-1) (solid content: 50%) 100 parts (2) Rutile type titanium dioxide 25 parts (3) Acrylic resin for pigment dispersion (solid content: 50%) 13 parts (4 Next, a pressure-sensitive adhesive layer was formed in the same manner as in Example 2 except that 5.5 parts of "E-05C" (trade name) (manufactured by Soken Chemical Co., Ltd.) was used as a curing agent. Thus, a retroreflective sheet laminate was obtained. Thereafter, aging was performed under the same conditions as in Example 1.

(Comparative Example 1)
A raw retroreflective sheet was obtained in the same manner as in Example 1, and an adhesive layer was formed by the following method. 100% by weight of an acrylic acid alkyl ester copolymer resin "Alloset HI-81D" (trade name) (manufactured by Nippon Shokubai Co., Ltd.) having a solid content of 39% by weight as a resin for an adhesive and a curing agent " 1.2 parts by weight of "Coronate L-55E" (trade name) [manufactured by Nippon Polyurethane Industry Co., Ltd.] were stirred and mixed to prepare an adhesive solution. The pressure-sensitive adhesive solution was applied on hard release paper and dried to form a pressure-sensitive adhesive layer having a thickness of about 80 μm. Then, the surface of the primer layer of the retroreflective sheeting and the surface of the pressure-sensitive adhesive layer of the laminate of the release paper and the pressure-sensitive adhesive layer are bonded at a bonding pressure of 450 N / cm and a roll surface temperature of 70 ° C. The groove formed in the primer layer by embossing under heat and pressure was filled with a part of the pressure-sensitive adhesive layer. Thereafter, the release paper was peeled off, and a flexible polypropylene (PP) release film “Film Binner PP-S-80” (trade name) [manufactured by Fujimori Kogyo Co., Ltd., thickness 80 μm, Young's modulus 800 MPa] (made of resin) (Release film) to obtain a retroreflective sheet laminate. Thereafter, aging was performed under the same conditions as in Example 1.

(Comparative Example 2)
An original retroreflective sheeting was obtained in the same manner as in Example 1. Thereafter, an acrylic resin “Alloset HI-91D-3” (trade name) (trade name) having a carboxylic acid as a functional group having a solid content of 40% by weight as a pressure-sensitive adhesive resin and grafted with chlorinated PP and PE is used. ) Nippon Shokubai] and 0.3 parts by weight of a curing agent “Coronate L-55E” (trade name) (manufactured by Nippon Polyurethane Industry Co., Ltd.) were stirred and mixed to prepare an adhesive solution. A retroreflective sheet laminate was obtained in the same manner as in Comparative Example 1, except that the pressure-sensitive adhesive solution was applied on hard release paper and dried to form a pressure-sensitive adhesive layer having a thickness of about 40 μm. Thereafter, aging was performed under the same conditions as in Example 1.

(Comparative Example 3)
An original retroreflective sheeting was obtained in the same manner as in Example 1. Thereafter, 100 parts by weight of an acrylic / vinyl acetate copolymer-based resin “Cybinol AT-208” (trade name) (manufactured by Seiden Chemical Co., Ltd.) having a solid content of 43% by weight as a resin for an adhesive, and N, N, 2.2% solution of N ', N'-tetraglycidyl-m-xylylenediamine (toluene 91.9%, IPA 5.9%) "A-9" (trade name) [manufactured by Seiden Chemical Co., Ltd.] 1 Except for using parts by weight, a retroreflective sheet laminate was obtained in the same manner as in Comparative Example 2. Thereafter, aging was performed under the same conditions as in Example 1.

  Tables 1 and 2 show the physical property values of the obtained retroreflective sheet laminate. In Table 1, "thickness of the pressure-sensitive adhesive layer" means "thickness of the pressure-sensitive adhesive layer in a portion of the back surface side of the resin-made support sheet where no groove is formed".

(Note)
(1) Holding force: displacement length after 24 hours / fall time (2) Filling state of pressure-sensitive adhesive layer: The flexible polypropylene (PP) release film of the retroreflective sheet laminate is peeled off and heated. The filling state of the pressure-sensitive adhesive layer into the groove formed in the primer layer or the resin support sheet by pressure embossing was visually checked.
Evaluation criteria ：: The filling rate of the pressure-sensitive adhesive layer is 70 to 100%.
Δ: The filling rate of the pressure-sensitive adhesive layer is less than 50 to 70%.
X: The filling rate of the pressure-sensitive adhesive layer is less than 50%.

(3) Appearance evaluation criteria ：: No abnormalities such as wrinkles, blisters, bubbles, and peeling are observed on the surface of the retroreflective sheet.
×: Abnormalities such as wrinkles, blisters, bubbles, and peeling were observed on the surface of the retroreflective sheet.
(Appearance test method)
<Method-1>
A 650 mm x 1000 mm aluminum plate (thickness: KIWALITE Hand Squeeze Roll Applicator HSA2-130) having a nip roll hardness of 60 (measured with a hardness meter JIS K 6301 A type), rubber thickness of 10 mm, diameter of 110 mm, and rubber surface length of 1270 mm. 1 mm), a retroreflective sheet was attached to each other to prepare a test body, and the appearance of the retroreflective sheet surface of the test body immediately after the bonding and of the test body after standing in a 60 ° C. atmosphere for 24 hours was observed.
The sticking pressure when the above Hand Squeeze Roll Applicator HSA2-130 was used was 0.4 Mpa as a result of measurement with a KIWALITE Pressure Scaling Film.

<Method-2>
A 650 mm x 1000 mm aluminum plate (thickness) using a KIWALITE Hand Squeeze Roll Applicator HSA2-130 having a nip roll hardness of 25 (measured with a hardness meter JIS K6301 A type A), a rubber thickness of 10 mm, a diameter of 110 mm, and a rubber surface length of 1270 mm. (1 mm), a retroreflective sheet was attached to the test piece, and the appearance of the retroreflective sheet surface of the test piece immediately after the bonding and the test piece after left in an atmosphere of 60 ° C. for 24 hours were observed.
The sticking pressure when using the Hand Squeeze Roll Applicator HSA2-130 was 0.1 Mpa or less as a result of measurement using a KIWALITE Pressure Scaling Film.

<Method-3>
As shown in FIG. 11, three 68 mm × 148 mm aluminum plates (thickness 1 mm) and one 330 mm × 330 mm aluminum plate (thickness 1 mm) were arranged on a 600 mm × 800 mm aluminum plate (thickness 1 mm). A substrate was prepared in which the sheet was forcibly distorted when the retroreflective sheet was attached. Next, using a KIWALITE Hand Squeeze Roll Applicator HSA2-130 having a nip roll hardness of 60 (measured with a hardness meter JIS K6301 A type), a rubber thickness of 10 mm, a diameter of 110 mm and a rubber surface length of 1270 mm, a recursiveness of 340 mm × 660 mm The reflection sheet was bonded from a position 100 mm from the portion A of the substrate. Thereafter, the retroreflective sheet is cut along a 330 mm × 330 mm aluminum plate (thickness: 1 mm) to prepare a test piece, and the test piece immediately after bonding and the test piece sheet surface after being left in a 60 ° C. atmosphere for 24 hours. Was observed.

  The sticking pressure when the above Hand Squeeze Roll Applicator HSA2-130 was used was 0.4 Mpa as a result of measurement with a KIWALITE Pressure Scaling Film.

  From the results of the above Examples and Comparative Examples, the groove on the back surface side of the resin support sheet formed by the heat and pressure embossing is filled with a part of the adhesive layer, and the residual ratio of the adhesive layer and the drop When the time was in the specific range, no abnormality such as wrinkles, blisters, bubbles, and peeling was observed on the surface of the retroreflective sheet, and it was confirmed that the problem of the conventional product could be improved.

  The retroreflective sheet of the present invention is a retroreflective sheet that prevents appearance abnormalities such as wrinkles and blisters that occur over time after being attached to a substrate, and includes road signs, guide signs, safety guidance sign display boards, or other It is useful as a safety sign.

Sectional drawing which shows the process of forming a reflective film on a glass sphere in an example of the manufacturing method of this invention. Sectional drawing which shows the process of forming the resin-made support sheet in an example of the manufacturing method of this invention. Sectional drawing which shows the process of transferring a glass ball in an example of the manufacturing method of this invention. Sectional drawing which shows the process which embedded the glass ball in the resin-made support sheet in an example of the manufacturing method of this invention. FIG. 4 is a cross-sectional view showing a step of exposing a non-reflective surface of a glass sphere in an example of the production method of the present invention. FIG. 3 is a cross-sectional view showing a step of embossing under pressure from the back side of the resin support sheet in one example of the production method of the present invention. FIG. 4 is a cross-sectional view illustrating the heating and pressing embossing in an example of the production method of the present invention. Sectional drawing which shows the process which covered the embossing molding surface side with the release material which has the heat-resistant in which the adhesive layer was formed in an example of the manufacturing method of this invention. FIG. 4 is a cross-sectional view showing a step of replacing a heat-resistant release material with a resin release film in one example of the production method of the present invention. Sectional drawing which shows the capsule cube corner type retroreflective sheeting after heating-press embossing in an example of the manufacturing method of this invention. FIG. 4 is a view for explaining an appearance measuring method used in an example of the present invention. FIG. 2 is an explanatory view showing a measuring method using a Yamamoto-type cohesive force measuring device used in an example of the present invention. FIG. 1 is a schematic perspective reference view of a Yamamoto-type cohesive force measuring device used in an embodiment of the present invention.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Cover film 2 Glass ball 3 Metal reflective film 4 Resin support sheet 5 Primer layer 6,8 Polyester film 7 Glass ball temporary fixing layer 9 Emboss roll 10 Emboss groove 11 Adhesive layer 12 Release paper 13 Resin release film 14 Cube corner Mold retroreflective element 21 Adherend 22 Load 23 Load 24 Load pulley 25 Side pulley 26 Retroreflective sheet 27 Tightening screw 28 Micrometer 29 Coil 30 Core 31 Electric micrometer 32 Jig 34 Display 35 Core holding block 36 Press roller 37 Yarn

Claims (16)

A plurality of retroreflective elements;
A resin support sheet,
A transparent cover film disposed on the surface side of the resinous support sheet,
And an adhesive layer formed on the back side of the resinous support sheet,
The retroreflective element is held on at least one of the resin support sheet and the cover film,
The resin-made support sheet and the cover film are joined by heat and pressure embossing from the back side of the resin-made support sheet to form a joint,
It is a retroreflective sheeting in which the groove of the bonding portion is formed on the back surface side of the resin-made support sheet,
The groove is filled with a part of the pressure-sensitive adhesive layer,
A retroreflective sheet wherein the residual ratio of the pressure-sensitive adhesive layer is in the range of 10% or more and 50% or less, and the falling time of the pressure-sensitive adhesive layer is in the range of 10 hours or more and 150 hours or less.
Residual rate (%) = (residual displacement ÷ initial displacement) × 100
The initial displacement was measured using a Yamamoto-type cohesive force measuring device, and the 10 mm × 5 mm retroreflective sheet was subjected to JIS Z 0237 on a mirror-finished flat plate made of SUS304 steel plate specified in JIS G 4305 having a width of 5 mm. Crimping is performed using a specified crimping device. Immediately after the crimping, a load of 17 g is applied to both ends of the retroreflective sheet via a thread. Thereafter, a load of 200 g for measurement is further applied to one of the loads, and 5 minutes. The deviation (mm) between the flat plate and the retroreflective sheet that occurs later means
The residual displacement means a shift between the flat plate and the retroreflective sheet, which occurs 10 minutes after the removal of the load of 200 g.
The drop time means the drop time of the retroreflective sheet when a 9.8 N load is applied in a holding force test at 40 ° C. according to the holding force test of JISZ0237. The retroreflective sheet according to claim 1, wherein a filling rate of the groove by the pressure-sensitive adhesive layer is 50% or more.
Filling rate (%) = [(AB) ÷ A] × 100
A is an area of the groove per unit area of the retroreflective sheet,
B means the area of a void formed at the interface between the groove and the pressure-sensitive adhesive layer per unit area of the retroreflective sheet. The retroreflective sheet according to claim 1 or 2, wherein the residual ratio is in a range of 15% or more and 45% or less. The retroreflective sheet according to any one of claims 1 to 3, wherein the falling time is in a range from 20 hours to 140 hours. The retroreflective sheet according to any one of claims 1 to 4, wherein a thickness of the pressure-sensitive adhesive layer in a portion of the back surface of the resin-made support sheet where the groove is not formed is in a range of 20 m to 110 m. The retroreflective sheet according to claim 1, wherein the pressure-sensitive adhesive layer is formed from a rubber-based resin or an acrylic-based resin. The retroreflective element is a transparent sphere, the hemisphere of which is covered with a reflector,
The retroreflective sheet according to claim 1, wherein a hemispherical side of the transparent sphere covered with the reflecting mirror is held so as to be embedded in the resin support sheet. A retroreflective sheet laminate comprising the retroreflective sheet according to any one of claims 1 to 7, and a resin release film,
The retroreflective sheet laminate, wherein the resin release film is laminated on the pressure-sensitive adhesive layer. The retroreflective sheet laminate according to claim 8, wherein the resin release film is a flexible resin film having a Young's modulus of 50 MPa or more and 2000 MPa or less. The retroreflective sheet laminate according to claim 9, wherein the flexible resin film is an unstretched polypropylene film or a low-density polyethylene film. A method for producing a laminate of a release material having heat resistance and the retroreflective sheet according to any one of claims 1 to 7,
A plurality of retroreflective elements;
A resin support sheet,
Including a transparent cover film disposed on the surface side of the resin-made support sheet,
The retroreflective element is held on at least one of the resin support sheet and the cover film,
The resin-made support sheet and the cover film are joined by heat and pressure embossing from the back side of the resin-made support sheet to form a joint,
A step of preparing a raw sheet of a retroreflective sheeting in which the grooves of the bonding portion are formed on the back surface side of the resin-made support sheet;
Forming a pressure-sensitive adhesive layer on the heat-resistant release material,
On the back side of the retroreflective sheeting, the heat-resistant release material on which the pressure-sensitive adhesive layer is formed is arranged, and from the heat-resistant release material side, a roll surface of 50 ° C or more and 90 ° C or less. Bonding at a temperature with a linear pressure between the rolls of 100 N / cm or more and 800 N / cm or less to partially fill the pressure-sensitive adhesive layer in the grooves of the resin-made support sheet. A method for producing a laminate of the material and the retroreflective sheet according to claim 1. The heat-resistant release material is a paper having a thickness of 20 μm or more and 200 μm or less, a synthetic resin laminated paper having a thickness of 30 μm or more and 220 μm or less, or a polypropylene film or a polyester film having a thickness of 15 μm or more and 250 μm or less. Manufacturing method. The manufacturing method according to claim 11 or 12, further comprising a step of subjecting the pressure-sensitive adhesive layer to an aging treatment under an environment of 23 ± 2 ° C and a relative humidity of 65 ± 5% for 7 days. The heat-resistant release material manufactured by the manufacturing method according to claim 11 or 12, and the heat-resistant release material are peeled from a laminate of the retroreflective sheet according to claim 1, 9. The method for producing a retroreflective sheet laminate according to claim 8, comprising a step of attaching to a resin release film. The method of manufacturing a retroreflective sheet laminate according to claim 14, further comprising a step of subjecting the pressure-sensitive adhesive layer to an aging treatment under an environment of 23 ± 2 ° C and a relative humidity of 65 ± 5% for 7 days. A heat-resistant release material manufactured by the manufacturing method according to claim 13 and a laminate of the retroreflective sheet according to claim 1, wherein the heat-resistant release material is peeled off, and a resin-made release material is used. The method for producing a retroreflective sheet laminate according to claim 8, comprising a step of replacing the sheet with a release film.

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