JP4666541B2 - Cover sheet - Google Patents

Description

【００５１】
表より実施例では、樹脂発泡体からなる支持基材及び外表面粗面化の粘着層を有することで小石等が衝突しても塗膜が損傷せず、剥離後に段差等の接着カバー痕も残存せずに浸入雨水を拡散して揮散させることがわかる。また半径５０cmの塗装管への接着カバーを試みたが効率よく接着でき、浮き等を発生することもなかった。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is a cover suitable for protecting the surface of automobile bodies and parts, and for protecting the surface of decorative plywood and coated steel sheets, etc. because it is excellent in preventing damage caused by impacts and following the curved surface, and is difficult to alter and discolor the coating film. Regarding the sheet.
[0002]
[Prior art]
Conventionally, when painting finished automobiles and their parts are loaded on trucks and ships and transported to remote places such as overseas, the coating of dust or dirt, rain or stone particles, etc. As a means for preventing damage, glossy blurring, or discoloration, it has been known to apply a wax-based coating material with a thickness of 5 to 40 μm. However, it is difficult to form a uniform wax coating and it is difficult to obtain uniform protection, it is easy to get dirty, it is vulnerable to acid rain, and the paint coating penetrates the wax and causes discoloration. In addition, there is a problem that a lot of labor is required for the application and removal of the wax coating, and that environmental problems such as the use of solvents and the treatment of waste liquids are easily induced.
[0003]
On the other hand, various surface protection sheets are known in which an adhesive layer is provided on a support substrate made of a film, and for coating film protection, such as a radiation-cured adhesive layer having a low glass transition point, polyisobutylene, etc. There have been proposed those provided with a rubber-based adhesive layer (Japanese Patent Laid-Open Nos. 2-199184 and 6-73352). According to such a sheet system, the above-described problems due to the wax system can be overcome.
[0004]
However, with the conventional protective sheet, it is possible to prevent the occurrence of damage by providing a sufficient protection function against relatively small impact objects such as dust and rain, but the impact object is pebbles, fences, When the tool size is increased, the protective function is insufficient and the coating film is damaged.
[0005]
[Technical Problem of the Invention]
Measures to increase the film thickness are effective against the problem of insufficient protective function described above, but in that case, when the film peels off after being adhered to the paint film due to increased stress or rigidity, it will deal with the paint film, especially the sheet edge. Protective sheet that is likely to cause streaky recesses due to steps in the coating part at the position where it occurs, and that adhesion failure such as floating is likely to occur on the curved surface part, causing appearance defects and peeling problems during transportation. The practicality of is greatly hindered. Therefore, the present invention protects the coating film from damage to medium-sized collision objects such as pebbles, ridges, and work tools that are larger than dust, rain, etc., while preventing appearance defects and peeling during transportation. The challenge is to develop cover sheets that satisfy the functions.
[0006]
[Means for solving problems]
The present invention provides a cover sheet characterized in that an adhesive layer having a roughened outer surface is provided on one side of a support substrate made of a resin foam.
[0007]
【The invention's effect】
According to the present invention, even when the thickness is increased by using a resin foam-based support base material, it exhibits good flexibility and appropriate expansion / contraction tolerance, and can follow deformation well even on a curved surface portion. Adhesive cover can be produced without generation of steps, and it is difficult to cause steps on the peeled film, and it can prevent peeling during transportation and appearance failure, as well as pebbles that are larger than dust and rain due to thickening and foam structure cushioning. A protective function that prevents damage to the coating film even when a medium-sized object such as a bag or work tool collides. In addition, the use of the above-mentioned foamed base material enables the formation of an adhesive layer with a rough outer surface structure reflecting its surface uneven structure, making it difficult for air bubbles to enter the adhesive cover, resulting in less wrinkling and working efficiency. Adhesion treatment can be performed well, and peelability and volatilization of infiltrated rainwater can be improved to prevent adhesion cover marks from being formed on the peeled coating film.
[0008]
Therefore, as a result of the above, a good adhesion state can be maintained for a long time to prevent the peeling phenomenon during transportation and the damage of the coating film due to a collision object, and it can be easily peeled off after the protection purpose is achieved (Japanese Patent Laid-Open No. 9-235525) In the case of a pressure-sensitive adhesive layer whose surface has been roughened by embossing, a cover sheet that can prevent the transfer of the generated uneven structure to the coating film and the occurrence of adhesive residue after peeling (contamination due to residual adhesive layer) Obtainable.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The cover sheet by this invention consists of what provided the adhesion layer which roughened the outer surface on the single side | surface of the support base material which consists of a resin foam. The pressure-sensitive adhesive layer can be formed using, for example, one or more appropriate pressure-sensitive adhesives such as rubber, acrylic, and urethane, and the pressure-sensitive adhesive includes one or more appropriate polymers as a base polymer. It may be. In particular, rubber-based pressure-sensitive adhesives can preferably be used in which a rubber-based polymer having no unsaturated bond is used as a base polymer from the viewpoint of long-term stability of adhesive properties.
[0010]
Incidentally, examples of the rubber polymer include polyisobutylene, butyl rubber, diene polymers such as polyisoprene and polybutadiene and hydrogenated products thereof, ethylene / propylene rubber, ethylene / α-olefin copolymer, ethylene / propylene / α- Olefin polymers such as olefin copolymers and propylene / α-olefin copolymers, styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-butylene copolymers / styrene (SEBS) A / B / A type styrene block polymer such as styrene / ethylene / propylene copolymer / styrene (SEPS), styrene / butadiene (SB), styrene / isoprene (SI), styrene / ethylene-butylene copolymer ( SEB) and styling・ A / B type styrene block polymers such as ethylene-propylene copolymer (SEP), random copolymers of styrene and diene hydrocarbons such as styrene / butadiene rubber and their hydrogenated products, styrene / ethylene-butylene copolymer A / B / C type styrene / olefin crystal block polymer such as polymer / olefin crystal (SEBC), C / B / C type olefin crystal system such as olefin crystal / ethylene-butylene copolymer / olefin crystal (CEBC) Examples include block polymers. The rubber-based pressure-sensitive adhesive may have one or two or more rubber-based polymers as a base polymer.
[0011]
When forming the adhesive layer, for example, softening agents, olefin polymers, silicone polymers, acrylic polymers, tackifiers, anti-aging agents, hindered amines, etc. An appropriate additive such as a stabilizer and an ultraviolet absorber, and other fillers and pigments such as calcium oxide, magnesium oxide, silica, zinc oxide, and titanium oxide can be blended.
[0012]
The blending of the softening agent is usually effective for improving the adhesive strength. Examples of the softener include low molecular weight polyisobutylene and polybutene, polyisoprene and polybutadiene, hydrogenated polyisoprene and hydrogenated polybutadiene, and a reactive group such as a hydroxyl group, a carboxyl group, and an epoxy group introduced at one or both ends thereof. Derivatives, ethylene / α-olefin copolymers, ethylene / propylene / α-olefin copolymers, olefin polymers such as propylene / α-olefin copolymers and ethylene / propylene rubber, process oils, naphthenic oils, castor oils, One or more of linseed oil, soybean oil, phthalate plasticizer, phosphate ester plasticizer, liquid aliphatic petroleum resin and the like can be used.
[0013]
The number average molecular weight of the softener that can be preferably used from the standpoints of prevention of substance transfer to the adherend such as a coating film and appropriate increase in the adhesive strength to the adherend is 1,000 to 300,000, especially 2000. ~ 150,000, especially 3000 ~ 100,000. The blending amount of the softening agent can be appropriately determined according to the adhesive force and the like, but generally, the blending amount is 100 parts by weight or less per 100 parts by weight of the base polymer, especially 60 parts by weight or less, and particularly preferably 40 parts by weight or less. .
[0014]
On the other hand, an olefin polymer can also be blended for the purpose of suppressing an increase in adhesion to the adherend. As such an olefin polymer, an appropriate polymer having a higher molecular weight than the above-described polyolefin softener can be used. For example, low density or linear low density, medium density or high density polyethylene, polypropylene, ethylene / α-olefin copolymer, ethylene / propylene / α-olefin copolymer or propylene / α-olefin copolymer Examples thereof include a polymer, an ethylene / ethyl (meth) acrylate copolymer, an ethylene / methyl (meth) acrylate copolymer, and an ethylene / propylene rubber. Such olefinic polymers can be used alone or in combination of two or more, and the amount of the olefinic polymer can be appropriately determined according to the adhesive strength and the like. In general, a blending amount of 50 parts by weight or less, especially 30 parts by weight or less, particularly 20 parts by weight or less is preferred per 100 parts by weight of the base polymer.
[0015]
Moreover, the blending of the silicone polymer is usually effective for improving the peelability. As the silicone-based polymer, one or more appropriate molecular weights having a siloxane bond as a skeleton can be used. Examples include dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane and their modified products such as epoxy-based, alkyl-based, amino-based, carboxyl-based, alcohol-based, fluorine-based, alkyl-aralkyl polyethers. And modified products such as epoxy-polyethers and polyethers. The blending amount of the silicone polymer is 5 parts by weight or less, especially 3 parts by weight or less, particularly 0.005 to 2 parts by weight, per 100 parts by weight of the base polymer, from the viewpoints of good adhesive formability and releasability stability. Part is preferred.
[0016]
On the other hand, the blending of the acrylic polymer is aimed at the expression of good adhesion to the adherend due to the improvement of wettability and the suppression of the daily increase of the adhesion at high temperatures. From this point, the weight average molecular weight is 1000 Up to 500,000 acrylic polymers are preferably used. That is, the acrylic polymer having the molecular weight exhibits a liquid state at normal temperature and is oriented on the surface of the adhesive layer due to the compatibility with the base polymer, thereby exhibiting good wettability to the adherend. It is considered that it exhibits adhesive strength and is stable against heat and exhibits good releasability at the time of peeling.
[0017]
In the above, if the weight average molecular weight of the acrylic polymer is less than 1000, the molecular weight may be too low and the effect of improving the adhesive strength may be poor, and if it exceeds 500,000, the stability over time and the peelability after long-term adhesion may be poor. is there. Acrylic polymers that can be preferably used from the viewpoints of improving adhesive strength, stability over time and releasability, have a weight average molecular weight of 3,000 to 300,000, especially 5,000 to 100,000, especially 10,000 to 50,000. belongs to. An acrylic polymer that can be preferably used in view of wettability to an adherend such as a coating film has a glass transition temperature of 25 ° C. or lower, especially 0 ° C. or lower, particularly −10 ° C. or lower.
[0018]
One or two or more kinds of acrylic polymers can be used, and there are no particular limitations on the forming monomers. Incidentally, as an example, one or more of (meth) acrylic acid esters having an alkyl group having 1 to 18 carbon atoms may be copolymerized with an acrylic pressure-sensitive adhesive such as (meth) acrylamide if necessary. And those obtained by polymerization treatment with an appropriate monomer such as solution polymerization. Such acrylic polymers include, for example, trade name Polyflow No. 55 and Polyflow No. There are also commercially available products such as 50E (manufactured by Kyoeisha Chemical Co., Ltd.), Disparon LC-951, Disparon LC-955, Disparon LC-1985 (manufactured by Enomoto Kasei), Modaflow (manufactured by Monsanto).
[0019]
The blending amount of the acrylic polymer is preferably 0.05 to 40 parts by weight per 100 parts by weight of the base polymer. If the blending amount is less than 0.05 parts by weight, the effect of improving the adhesive strength may be poor due to insufficient blending. If the blending amount exceeds 40 parts by weight, the adhesive strength is greatly reduced due to orientation on the surface of the adhesive layer. Problems such as peeling may easily occur. A preferable blending amount of the acrylic polymer from the viewpoint of formability in a good adhesion state is 30 parts by weight or less per 100 parts by weight of the base polymer, especially 0.05 to 20 parts by weight, particularly 0.1 to 10 parts by weight. It is.
[0020]
Furthermore, the formulation of a tackifier is usually effective for improving the adhesive strength. Examples of the tackifier include petroleum resins such as aliphatic, aromatic, aliphatic / aromatic copolymer systems, and alicyclic systems, coumarone indene resins, terpene resins, terpene phenol resins, and ( Alkyl) phenol-based resins, rosin-based resins, polymerized rosin-based resins, xylene-based resins, or their pressure-sensitive adhesives such as hydrogenated resins can be used singly or in combination. The blending amount of the tackifier is 80 parts by weight or less per 100 parts by weight of the base polymer, especially 40 parts by weight or less, especially 20 weights from the viewpoint of improving the adhesive force by avoiding the occurrence of the adhesive residue problem due to the decrease in cohesive force. Part or less is preferred.
[0021]
On the other hand, as a support base material to which the adhesive layer is attached, one made of a resin foam is used, and an appropriate one can be used as the resin foam depending on the purpose of use of the cover sheet. By the way, examples of the resin foam include propylene polymers such as block systems, random systems and graft systems containing ethylene as a component, ethylene polymers such as low density, high density and linear low density, ethylene -Olefin-based polymer, polystyrene, polyester, polyurethane, polyamide, and the like described above, which contain olefins such as propylene copolymer and ethylene / α-olefin copolymer, or monomers other than olefin such as ethylene / styrene copolymer, etc. Examples thereof include styrene block copolymers and hydrogenated products thereof, styrene random copolymers and one or more of hydrogenated products thereof.
[0022]
A foam made of an olefin-based polymer can be particularly preferably used from the viewpoint of incineration processability and discardability of the cover sheet after peeling. For resin foam, for example, for the purpose of preventing deterioration, an appropriate additive such as an antioxidant, an ultraviolet absorber, a light stabilizer such as a hindered amine, an antistatic agent, or an inorganic filler exemplified in the above adhesive layer Can also be blended. The thickness of the support substrate made of the resin foam is generally 0.1 to 50 mm, particularly 0.5 to 30 mm, and particularly 1 to 20 mm, but is not limited thereto.
[0023]
Resin foams include, for example, volatile organic foaming agents such as propane, (n, i) -butane, (n, i) -pentane, cyclopentane, hydrocarbons such as pentene and hexane and their halides, carbon dioxide and air. Inorganic nitrogen foaming agents such as azodicarbonamide, N, N'-dinitrosopentamethylenetetramine, azobisisobutyronitrile, and inorganic foaming agents such as sodium bicarbonate and calcium carbonate Foamed with an appropriate method, such as foamed with one or more suitable foaming agents such as, or foamed by mixing a commercially available foamable master badge and the above resin It may be.
[0024]
The resin foam may have an appropriate foaming structure such as independent foaming, continuous foaming, or a mixture thereof, and preferably has an independent foaming structure from the viewpoint of improving impact resistance. Although the expansion ratio is arbitrary, generally the expansion ratio is preferably 1 to 100 times, especially 2 to 50 times, particularly 5 to 40 times from the viewpoint of strength and cushioning properties.
[0025]
The support base material may be provided with a laminate layer on one side or both sides of the resin foam for the purpose of improving the strength and the invasion prevention property such as rainwater. In the case where the supporting substrate has the above-mentioned laminate layer, the adhesive layer can be provided on the laminate surface, or can be provided on the surface not having the laminate layer. In the present invention, as described above, the outer surface of the adhesive layer may be roughened by reflecting the uneven structure on the surface of the resin foam. In that case, the roughened state can be controlled by whether or not a laminate layer is interposed, and when the uneven structure on the surface of the resin foam is appropriate, it is preferable to provide an adhesive layer without the laminate layer, When the concavo-convex structure is too large, it is preferable to suppress the roughening (unevenness) of the outer surface of the adhesive layer by interposing a laminate layer.
[0026]
The laminate layer can be formed as an appropriate resin coating layer, a film adhesive layer, or the like, and as the resin, one or more of the appropriate ones exemplified in the above-mentioned foam can be used. Thermoplastic resins such as polymers, polyamides, and polyesters can be preferably used. Olefin polymers are particularly preferred from the viewpoint of incineration processability after peeling.
[0027]
The thickness of the laminate layer can be appropriately determined depending on the strength, curved surface followability, etc., and is generally 5 to 50 μm, especially 7 to 40 μm, and particularly preferably 10 to 30 μm. For example, a heat laminating method of a film, an adhesive method using an adhesive, a method of laminating a resin film on a resin foam, a method of applying a resin solution, etc. It can be done by the method.
[0028]
The cover sheet is formed, for example, by applying a solution of the adhesive layer forming material in a solvent or a hot melt to one side of the supporting substrate, or transferring the adhesive layer formed on the separator accordingly to one side of the supporting substrate. , Adhesive layer forming material by extrusion coating on one side of support substrate, Single layer lamination method of adhesive layer on one side of support substrate, Double layer lamination with laminate layer, Resin and foamable master badge A method of co-extrusion of a support substrate forming material and a pressure-sensitive adhesive layer made of a mixture of two layers or multiple layers, or a method of laminating a pressure-sensitive adhesive layer and a support substrate forming material such as a resin foam or a laminate layer in two or multiple layers It can carry out according to the formation method of a well-known adhesive sheet.
[0029]
A preferable method for forming a cover sheet from the viewpoint of production efficiency is a two-layer extrusion molding method of a foaming agent-containing resin and an adhesive layer, or a three-layer structure in which a laminate layer is provided between the resin layer and the adhesive layer or on the opposite side of the adhesive layer. It is a method in which a supporting substrate and an adhesive layer are simultaneously extruded and foam-molded, such as an extrusion molding method or a four-layer extrusion molding method in which a laminate layer is provided between a resin layer and an adhesive layer and on the opposite side of the adhesive layer. Note that the adhesive layer and the laminate layer may be foamed with a foaming agent if necessary.
[0030]
The pressure-sensitive adhesive layer provided on one side of the support base material has a roughened outer surface. As a result, the adhesion surface of the adhesive layer to the adherend can be made to have good volatility of infiltrated rainwater due to air permeability and moisture permeability, and the protective sheet trace is unlikely to remain on the adherend such as the coated film after peeling. can do.
[0031]
From the standpoint of balance between prevention of retention due to good volatilization of infiltrated rainwater and prevention of insufficient adhesion due to securing of adhesion area, the preferred roughened state on the outer surface of the adhesive layer is that the surface roughness is Ra according to JIS B 0601. 10 μm or more, especially 50 μm or more, especially 100 to 2000 μm, or / and Rmax, 30 μm or more, especially 100 μm or more, especially 500 to 5000 μm.
[0032]
The roughening of the outer surface of the adhesive layer described above can be formed by an appropriate method. By the way, as an example, solid coating is performed by the above-mentioned coating method or extrusion method, etc., and a roughening treatment such as a method of reflecting unevenness on the surface of the support substrate such as a resin foam on the adhesive surface or embossing is performed. There is a method in which an adhesive layer having a roughened outer surface is formed on a separator subjected to a method, embossing or the like, and then transferred.
[0033]
Further, for example, the adhesive layer forming material is made into a fiber by an appropriate method such as a melt blow method or a curtain spray method, and the deposited layer is deposited as a nonwoven fabric. Examples include a method in which the surface is roughened, and a method in which the pressure-sensitive adhesive layer forming material is partially coated in a dot shape or a lattice shape to form a pressure-sensitive adhesive layer whose outer surface is roughened. Therefore, the pressure-sensitive adhesive layer may be formed in a state of air permeability such as the non-woven fabric or the dot-like material.
[0034]
The thickness of the pressure-sensitive adhesive layer may be appropriately determined according to the adhesive strength and the like, and is generally 3 to 100 μm, especially 7 to 70 μm, particularly 10 to 50 μm. The adhesive layer can be protected by temporarily attaching a separator or the like until it is put into practical use as required. In addition, the surface of the adhesive layer is subjected to surface treatment for the purpose of controlling adhesiveness and adhesion workability, such as corona discharge treatment, ultraviolet irradiation treatment, flame treatment, plasma treatment, and sputter etching treatment, as necessary. You can also. The surface of the pressure-sensitive adhesive layer can be roughened by such surface treatment.
[0035]
The above-described surface treatment can be applied to the support layer-attached surface of the support base as necessary for the purpose of improving the adhesion of the adhesive layer. An undercoating treatment with a primer or the like is also effective for improving the adhesion of the adhesive layer. Also, on the surface of the supporting substrate that is not provided with an adhesive layer, a coating made of an appropriate release agent such as a silicone-based, long-chain alkyl-based, or fluorine-based material for the purpose of forming a wound body that can be easily rewound. Layers can also be provided.
[0036]
The cover sheet according to the present invention may be one that exhibits ultraviolet blocking properties. The UV-blocking cover sheet is excellent in long-term stability of good releasability without breakage or adhesive residue by preventing deterioration of the support substrate and the adhesive layer outdoors. A preferable ultraviolet blocking cover sheet has an ultraviolet transmittance of 190% to 370 nm at a wavelength of 5% or less, especially 3% or less, particularly 1% or less, and further 0.5% or less.
[0037]
The ultraviolet shielding cover sheet can be formed by an appropriate method using a supporting base material and / or an adhesive layer. Incidentally, for the supporting base material, for example, a method in which ultraviolet shielding particles are dispersedly held in a part or all of a forming member such as a resin foam or a laminate layer can be applied. Such a dispersion-holding system for ultraviolet blocking particles can also be applied to the adhesive layer. As a specific example, a resin foam or a laminate layer composed of the mixture obtained by mixing ultraviolet blocking particles and a thermoplastic resin or an adhesive layer forming material and applying an appropriate film forming method such as a T-die method or an inflation method. Or the system which makes an adhesion layer is mention | raise | lifted.
[0038]
Also, a UV-blocking supporting substrate can be obtained by a method of forming a coating film by adhering a coating liquid containing UV-blocking particles to the surface of a supporting substrate or a method using the above-described method together. The coating liquid is, for example, a dispersion obtained by mixing a binder component made of an appropriate resin such as acrylic, urethane, or polyester with a UV blocking particle through a medium made of an appropriate organic solvent such as toluene or water. Can be obtained as
[0039]
The application of the coating liquid can be performed by an appropriate method such as a dipping method in the liquid, a spraying method of the liquid, a coating method of the liquid using a gravure coater, a reverse coater, or the like. The thickness of the coating film may be determined as appropriate, but in general, a thickness of 40 μm or less, especially 20 μm or less, particularly 0.5 to 10 μm is preferable from the viewpoint of processing efficiency or thinning.
[0040]
As the ultraviolet blocking particles, suitable particles that reflect or absorb ultraviolet rays such as titanium white, red rose, zinc white, alumina, tin oxide and carbon black can be used. Of these, titanium white, zinc white and the like are preferable from the viewpoint of ultraviolet blocking effect. The particle size of the ultraviolet blocking particles may be determined as appropriate, but generally it is 0.005 to 5 μm, especially 0.01 to 1 μm based on the average particle size from the viewpoint of stability or long-term sustainability of the dispersed content. In particular, 0.02 to 0.5 μm is preferable.
[0041]
On the other hand, the ultraviolet blocking treatment can also be performed by a method in which a vapor deposition film made of an appropriate metal such as stainless steel is attached to the support substrate. In that case, the thickness of the deposited film or the like is preferably 10,000 mm or less, especially 10 to 5,000 mm, particularly 100 to 1,000 mm, from the viewpoint of maintaining good workability of the adhesive cover of the supporting substrate.
[0042]
The cover sheet according to the present invention is, for example, a coating film such as a polyester / melamine type, an alkyd / melamine type, an acrylic / melamine type, an acrylic / urethane type, an acrylic / polyacid curing agent type, particularly a bumper or a pebble with many curved portions. It can be preferably used for side surfaces of automobile bodies that are greatly affected by impact objects, surface protection during transportation of painted steel sheets and decorative plywood for home appliances, and after assembly of home appliances. In the application, the cover sheet according to the present invention can be overlaid on a sheet for protecting a coating film or protecting a surface including a conventional product, thereby preventing the generation of scratches caused by a collision object or the like more reliably.
[0043]
【Example】
Example 1
On one side of a polyethylene foam sheet (Sekisui Plastics Kogyo Kogyo Co., Ltd., Lightlon) having a rugged structure on the surface with a thickness of 1 mm, 100 parts of low density polyethylene (Nippon Polychem, Novatec LD) (parts by weight, the same applies hereinafter), 9 parts titanium oxide (manufactured by Ishihara Sangyo Co., Ltd., Taipei), 0.8 part UV absorber (manufactured by Ciba Specialty Chemicals Co., Ltd., Tinuvin 326) and 0.2 part of hindered amine light stabilizer (manufactured by Ciba Specialty Chemicals Co., Ltd., Kimasorb 944) A kneaded product made of is laminated to form a laminate layer having a thickness of 15 μm, and a toluene solution containing 100 parts of polyisobutylene having a weight average molecular weight of 870,000 and 20 parts of 30,000 polyisobutylene is formed on the other surface of the foamed sheet. It was applied and heated at 60 ° C. for 3 minutes to form a 30 μm thick adhesive layer to obtain a cover sheet.
[0044]
Example 2
A kneaded product of 100 parts of SEPS (Kuraray, Septon 2063), 40 parts of hydrogenated liquid polyisoprene (Kuraray, LIR-290) and 20 parts of hydrogenated petroleum resin (Arakawa Chemical Co., Alcon P-100) Two layers are extruded on one side of a foamed sheet according to Example 1 using an adhesive layer forming material made of polyethylene and a laminate layer forming material made of polyethylene (Novatech LD), and thick on the outside of a polyethylene laminate layer having a thickness of 5 μm. A cover sheet having a thickness of 30 μm was obtained.
[0045]
Example 3
Laminate layer forming material made of polyethylene kneaded material according to Example 1, foamed layer forming material made of foam compound (manufactured by Eiwa Kasei Co., Ltd., Polyslen), 100 parts of SEBS (manufactured by Shell Chemical Co., Kraton G1657), hydrogenated An adhesive layer forming material composed of a kneaded product of 20 parts of a petroleum resin (Alcon P-100) and 10 parts of polybutene (manufactured by Nippon Petrochemical Co., Ltd., HV-50) is extruded into three layers, and a foam layer having a thickness of 0.5 mm A cover sheet having a polyethylene laminate layer having a thickness of 10 μm on one side and an adhesive layer having a thickness of 30 μm on the other side was obtained.
[0046]
Comparative Example 1
A cover sheet was obtained according to Example 1 except that a polyethylene film having a thickness of 60 μm and a smooth surface was used instead of the foam sheet.
[0047]
Comparative Example 2
A cover sheet was obtained according to Example 2 except that a polyethylene film having a thickness of 1 mm and a smooth surface was used instead of the foam sheet.
[0048]
Comparative Example 3
A cover sheet was obtained according to Example 1 except that a polyethylene film embossed with a thickness of 60 μm was used instead of the foam sheet.
[0049]
Evaluation test
The cover sheets obtained in Examples and Comparative Examples were adhered to an acrylic / melamine coating film through the adhesive layer at room temperature, and the coating film was damaged in a chipping test with No. 6 silica sand, or left at 60 ° C. for 7 days. The presence or absence of a step (cover mark) in the coating film when peeled later was examined. Also, the cover sheet is bonded to the acrylic / melamine-based coating film through the adhesive layer by forming a bag-like void at room temperature, and water is poured into the void to form a water pool. The diffusivity was examined by the presence or absence of water in the part. When there is no water, there is diffusivity, and when there is, it means that there is no diffusivity.
[0050]
The results are shown in the following table. The table also shows the surface roughness Ra and Rmax on the outer surface of the adhesive layer.

[0051]
In the examples from the table, the coating substrate is not damaged even if pebbles collide by having a support base made of resin foam and an adhesive layer with roughened outer surface, and adhesive cover marks such as steps after peeling It can be seen that infiltration rainwater diffuses and volatilizes without remaining. In addition, an attempt was made to cover the coated tube with a radius of 50 cm, but it was possible to bond efficiently and no floating or the like occurred.

Claims (5)

Automobile bodies and parts of the coating a cover sheet for protection,
The pressure-sensitive adhesive layer whose outer surface is roughened is provided on one side of a support substrate made of a resin foam having a thickness of 0.5 to 30 mm, and the surface roughness of the outer surface of the pressure-sensitive adhesive layer is 10 μm or more and 30 μm based on Ra. cover sheet, characterized by satisfying the following and both 30μm or 80μm or less based on Rmax.   The cover sheet according to claim 1, wherein the supporting substrate has a laminate layer on one side or both sides thereof, and has an adhesive layer on the side of the laminate layer or the side not having the laminate layer.   The base polymer that forms the adhesive layer is polyisobutylene, butyl rubber, A / B / A type styrene block polymer, A / B / C type styrene / olefin crystal block polymer, C / B / C type olefin crystal block polymer The cover sheet according to claim 1 or 2, which is one or more of a random copolymer of styrene and a diene hydrocarbon or an olefin polymer.   The cover sheet according to any one of claims 1 to 3, wherein the support base material and the adhesive layer are simultaneously formed by a multilayer extrusion foaming method of two layers or three layers or more.   The cover sheet according to any one of claims 1 to 4, wherein the transmittance of ultraviolet rays having a wavelength of 190 to 370 nm is 5% or less.