JP2011189674A - Laminated sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated sheet which hardly occurs burrs or chips when the laminated sheet is blanked into a desired shape and which is excellent in processability when processed into a sealing material. <P>SOLUTION: The laminated sheet is obtained by laminating a synthetic resin film on one surface of an acrylonitrile-butadiene rubber foamed sheet so that the synthetic resin film can be exfoliated. The synthetic resin film has ≤80 MPa tensile strength, ≥250% elongation at break and ≤500 MPa elastic modulus. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laminated sheet.

  Sealing materials are used to maintain airtightness and watertightness in automobiles, buildings, electrical products, and the like. Most of the sealing materials are formed from urethane-based open-cell foams or rubber-based closed-cell foams, and are formed by punching out the foam into a desired shape. (Hereinafter, referred to as “seal part”) exhibits air tightness and water tightness (hereinafter also referred to as “sealability”).

  As described above, since the sealing material exhibits sealing properties only by the elastic recovery force of the foam in the compressed state, the elastic recovery of the foam when used over a long period of time or in a high temperature state in summer. There is a problem that the sealing force such as air tightness and water tightness is lowered due to the reduced strength.

  Therefore, Patent Document 1 discloses a solar cell panel sealing material comprising an elastic layer, an insulating resin film laminated on the elastic layer, and a first water-stopping adhesive layer laminated on the insulating resin film. Has been proposed.

  However, as described above, the sealing material is formed by punching into a desired shape. However, the foam and the insulating resin film are greatly different in terms of their flexibility, rigidity and elongation, and the sealing material is desired. There is a problem that it cannot be punched into the shape. In particular, the above-mentioned problem becomes more prominent as the thickness of the foam increases.

  Furthermore, a polyethylene terephthalate film is used as the insulating resin film. However, since the polyethylene terephthalate film has high rigidity, burrs and cutting debris are easily generated during punching molding, and this cut piece is the first water-stopping adhesive. When it adheres on the layer, there is a problem that the sealing performance of the sealing material is lowered.

  In addition, EPDM foam sheets and urethane resin foam sheets are commercially available as water-stop sealing materials, and the surface of the water-stop seal material is damaged before the water-stop seal material is placed at the location where water stop is desired. An insulating resin film is detachably laminated on the surface of the water sealing material so as not to stick. As described above, when the insulating resin film is laminated on the surface of the water-stopping sealing material, when the water-stopping sealing material is punched into a desired shape, a situation in which the water-stopping sealing material cannot be accurately punched frequently occurs and the yield decreases. Has the problem.

JP 2009-71233 A

  The present invention provides a laminated sheet excellent in processability to a sealing material having a desired shape with almost no burrs or cutting waste generated during stamping into the desired shape.

  The laminated sheet of the present invention is a laminated sheet in which a synthetic resin film is detachably laminated on one surface of an acrylonitrile-butadiene rubber foamed sheet, and the synthetic resin film has a tensile strength of 80 MPa or less and a tensile breaking elongation. 250% or more and a tensile elasticity modulus are 500 Mpa or less. The acrylonitrile-butadiene rubber foamed sheet may be simply abbreviated as “foamed sheet”.

  The foam sheet is composed of acrylonitrile-butadiene rubber. Note that acrylonitrile-butadiene rubber (NBR) is also referred to as nitrile rubber, nitrile-butadiene rubber, or acrylonitrile-butadiene copolymer rubber.

  The acrylonitrile-butadiene rubber may contain a petroleum resin or an ethylene-vinyl acetate copolymer. When the content of petroleum resin or ethylene-vinyl acetate copolymer is small, the effect of improving the sealing property of the foam sheet may not be exhibited. When the content is large, the foam sheet is used as a sealing material for a long period of time. In addition, since the petroleum resin or ethylene-vinyl acetate copolymer may bleed out and the sealing performance of the sealing material may decrease, the amount is preferably 3 to 30 parts by weight with respect to 100 parts by weight of acrylonitrile-butadiene rubber.

  The acrylonitrile-butadiene rubber may contain an antioxidant, an ultraviolet degradation inhibitor, a pigment, and the like as necessary.

  The 75% compressive strength in the thickness direction measured according to JIS K6767 in the acrylonitrile-butadiene rubber foamed sheet is preferably 100 to 300 kPa. When the 75% compressive strength is low, the followability to the seal portion becomes insufficient, and the sealability of the foamed sheet may be lowered. When the 75% compressive strength is high, the foamed sheet becomes too hard, the compression flexibility is reduced, or the repulsive force at the time of compression is increased. When the laminated sheet is used as a sealing material, the sealing part is deformed, and the sealing part The gap may be enlarged and the sealing performance may be reduced. The 75% compressive strength in the thickness direction measured in accordance with JIS K6767 in the foamed sheet may be adjusted by adjusting the Mooney viscosity of acrylonitrile-butadiene rubber, or by adjusting the density and bubble diameter of the foamed sheet. Good. The density of the foamed sheet can be controlled by adjusting the amount of foaming agent used when the foamed sheet is produced. The cell diameter of the foamed sheet can be controlled by adjusting the particle diameter of the foaming agent used in producing the foamed sheet or the crosslinking method.

  When the closed cell ratio of the foamed sheet is small, when the laminated sheet is used as a sealing material, the sealing performance of the sealing material may be lowered, so 30% or more is preferable and 50 to 100% is more preferable.

Here, the closed cell ratio of the foam sheet refers to that measured in the following manner. First, a test piece having a flat square shape with a side of 5 cm and a constant thickness is cut out from the foam sheet. Then, the thickness of the test piece is measured to calculate the apparent volume V ₁ of the test piece, and the weight W _{1 of the} test piece is measured.

Next, the apparent volume V ₂ occupied by the bubbles is calculated based on the following formula. The density of the resin constituting the test piece is 1 g / cm ³ .
Apparent volume occupied by bubbles V ₂ = V ₁ −W ₁

Subsequently, the test piece is submerged in distilled water at 23 ° C. to a depth of 100 mm from the water surface, and a pressure of 15 kPa is applied to the test piece over 3 minutes. After that, the test piece is taken out of the water, the water adhering to the surface of the test piece is removed, the weight W _{2 of the} test piece is measured, and the open cell rate F ₁ and the closed cell rate F ₂ are calculated based on the following formulas. To do.
Open cell ratio F ₁ (%) = 100 × (W ₂ −W ₁ ) / V ₂
Closed cell ratio F ₂ (%) = 100−F ₁

And when the apparent density according to JIS K7222 of the foamed sheet is small, the foamed sheet becomes brittle and the strength cannot be maintained, and when the laminated sheet is used as a sealing material, the sealing performance is maintained for a long period of time. On the other hand, if it is large, the foamed sheet becomes hard and the compression flexibility decreases or the repulsive force at the time of compression increases, and when the laminated sheet is used as a sealing material, the seal portion is deformed, and the gap between the seal portions is increased. Since it expands and sealing performance falls, 20-100 kg / m < ³ > is preferable. In addition, a seal part means the part which has the space part which wants to block | close with a sealing material.

  Moreover, the thickness of a foam sheet is although it does not specifically limit, 0.5-50 mm is preferable, 1-20 mm is more preferable, 2-10 mm is especially preferable.

  And the synthetic resin film is laminated | stacked on one side of a foam sheet so that peeling is possible. This synthetic resin film plays the role of a protective sheet for protecting the surface of the foam sheet, and is peeled off and removed from one surface of the foam sheet immediately before using the sealing material formed by punching the laminated sheet. The synthetic resin constituting the synthetic resin film is not particularly limited as long as the synthetic resin film has the physical properties described later. For example, polypropylene resin, polyethylene resin, polyvinyl chloride, ethylene-acetic acid A vinyl copolymer, a polyamide-type resin, etc. are mentioned. In addition, a synthetic resin may be used independently or 2 or more types may be used together.

  The polypropylene resin is not particularly limited, and examples thereof include a propylene homopolymer, a copolymer of propylene and another olefin, and the like, and may be used alone or in combination of two or more. Further, the copolymer of propylene and other olefins may be any of a block copolymer, a random copolymer, and a random block copolymer.

  Examples of the olefin copolymerized with propylene include α such as ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene and 1-decene. -Olefin etc. are mentioned.

  The polyethylene resin is not particularly limited, and examples thereof include low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, linear medium density polyethylene, and linear high density polyethylene. Polyethylene resin may be used independently or 2 or more types may be used together.

  When the tensile strength of the synthetic resin film is high, the laminated sheet is not punched into the desired shape or burrs are generated, so that it is limited to 80 MPa or less, and if it is too low, wrinkles occur in the synthetic resin film. Since it becomes easy and sealability may fall when a laminated sheet is used as a sealing material, 20-60 Mpa is preferable. The tensile strength of the synthetic resin film needs to satisfy the above values in all directions. The tensile strength of the synthetic resin film is a value measured according to JIS Z1707. The tensile strength of the synthetic resin film needs to be 80 MPa or less in any direction. And the tensile strength of a synthetic resin film can be adjusted by adjusting the kind of synthetic resin, a weight average molecular weight, or a melt flow rate, or extending | stretching a synthetic resin film.

  In addition, if the tensile elongation at break of the synthetic resin film is small, it is not possible to follow the softness of the foamed sheet at the time of punching the laminated sheet, and as a result, the laminated sheet cannot be punched into the desired shape or burrs are generated. Therefore, it is limited to 250% or more, preferably 350% or more, and more preferably 500 to 1000%. The tensile break elongation of the synthetic resin film needs to satisfy the above values in all directions. In addition, the tensile elongation at break of a synthetic resin film refers to a value measured according to JIS Z1707. And the tensile elongation at break of a synthetic resin film can be adjusted by adjusting the kind of synthetic resin, a weight average molecular weight, or a melt flow rate, or extending | stretching a synthetic resin film.

  When the tensile modulus of the synthetic resin film is large, when the laminated sheet is stamped and formed, it does not punch out into a desired shape or burrs are generated, so it is limited to 500 MPa or less, preferably 450 MPa or less, and 100 to 400 MPa. Is more preferable. The tensile elastic modulus of the synthetic resin film needs to satisfy the above values in all directions. In addition, the tensile elasticity modulus of a synthetic resin film says the value measured based on JISK7127. And the tensile elasticity modulus of a synthetic resin film can be adjusted by adjusting the kind of synthetic resin, a weight average molecular weight, or a melt flow rate, or extending | stretching a synthetic resin film.

  Furthermore, if the thickness of the synthetic resin film is thin, wrinkles are likely to occur in the synthetic resin film, and the sealing performance may be lowered when the laminated sheet is used as a sealing material. In such a case, since the desired shape is not punched or burrs are generated, 20 μm to 1 mm is preferable, and 40 μm to 200 μm is more preferable.

  Synthetic resin films satisfying the above physical properties are commercially available from Toyobo Co., Ltd. under the trade names “Rix Film L4102 (AM)”, “Rix Film L6102 (AM)”, and “Rix Film L6102 (AM) L4182”. Linear low density polyethylene film, linear low density polyethylene film commercially available from Tamapoly under the trade names “SE film SE625M”, “SE film SE625L”, “SE film SE620M”, “SE film SE620L”, Product names “TUX L-LDPE Film HC”, “TUX L-LDPE Film HC-E”, “TUX L-LDPE Film FCD-NP”, “T” U.X L-LDPE film TCS ”,“ T.U.X L-LD A linear low density polyethylene film commercially available from “E film FCS”, “TUX L-LDPE film MCS” and “TUX L-LDPE film VCS”. Linear low-density polyethylene film marketed by "Film" and "Ramilon Film", linear low-density polyethylene film marketed by Nimura Chemical Industry Co., Ltd. under the trade name "Dazai Film", commercialized by Tamapoly Names “SB film SB-5”, “SB film SB-7”, “SB film SB-10”, “AV film, AV-51”, ethylene-vinyl acetate copolymer film, Santox Polypropylene resin marketed by the company under the trade names “Santox EP32” and “Santox EP72” Films, trade names “Tosero Film SC”, “Tosero Film E2C”, “Tosero Film GHC”, “Tosero Film GLC”, “Tosero Film RXC-21”, “RXC-22” Available from Toyobo Co., Ltd. under the trade names "Toyobo Pyrene Film-CT P1151", "Toyobo Pyrene Film-CT P1153", and "Toyobo Pyrene Film-CT P1146". -Based resin films, polypropylene resin films marketed under the trade names "Pureley" and "Super Pure Ray" by Idemitsu Unitech, and polyamides marketed under the trade name "Rayfan 8700" from Toray Film Processing Co., Ltd. Resin film, etc. .

  Next, the manufacturing method of a lamination sheet is demonstrated. The manufacturing method of the foam sheet which comprises the lamination sheet is demonstrated. First, a foamable resin sheet containing acrylonitrile-butadiene rubber and a pyrolytic foaming agent is produced.

  As a method for producing the foamable resin sheet, a known method can be employed. For example, a foamable raw material composition containing (1) acrylonitrile-butadiene rubber, a crosslinking agent, and a pyrolytic foaming agent is required. (2) Acrylonitrile-butadiene rubber, which is kneaded by a kneader such as a Banbury mixer or a pressure kneader, and then kneaded continuously by a calendar, an extruder, a conveyor belt casting, or the like. (2) Acrylonitrile-butadiene rubber And a foamable raw material composition containing a pyrolytic foaming agent are kneaded in a kneader such as a Banbury mixer or a pressure kneader as necessary, and then kneaded continuously by a calendar, an extruder, a conveyor belt casting, or the like. To produce a foamable resin sheet, and this foamable resin sheet is irradiated with ionizing radiation to crosslink the foamable resin sheet. And manufacturing method of the foamed resin sheet.

  Examples of the crosslinking agent include organic peroxides, sulfur, sulfur compounds and the like, and organic peroxides are preferable. Examples of ionizing radiation include α rays, β rays, γ rays, and electron beams. Examples of the organic peroxide include diisopropylbenzene hydroperoxide, 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, t-butyl perbenzoate, cumyl hydroperoxide, t-butyl hydroperoxide, and 1,1. -Di (t-butylperoxy) -3,3,5-trimethylhexane, n-butyl-4,4-di (t-butylperoxy) valerate, α, α'-bis (t-butylperoxyisopropyl) ) Benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, t-butylperoxycumene and the like. Examples of the sulfur compound include tetramethylthiuram disulfide, tetra Methyl thiuram monosulfide, zinc dimethyldithiocarbamate, 2-mercaptoben Examples include zothiazole, dibenzothiazyl disulfide, N-cyclohexyl-2-benzothiazole sulfenamide, Nt-butyl-2-benzothiazole sulfenamide, sulfur monochloride, sulfur dichloride and the like.

  Also, if the content of the crosslinking agent in the foamable raw material composition is small, the foam fraction of the foamable raw material composition will not be suitable for foaming and foam breaks. In many cases, the gel fraction (degree of crosslinking) of the foamable raw material composition is excessively increased, and the foamable raw material composition may not foam. Therefore, the total amount of synthetic resin and rubber is 100 wt. 0.05-10 weight part is preferable with respect to part, and 0.1-7 weight part is more preferable.

  The pyrolytic foaming agent refers to those that decompose by heating to generate foaming gas. Such pyrolytic foaming agent is not particularly limited, and examples thereof include azodicarbonamide, benzenesulfonylhydrazide, and dinitroso. Examples include pentamethylenetetramine, toluenesulfonyl hydrazide, and 4,4-oxybis (benzenesulfonyl hydrazide). In addition, a thermal decomposition type foaming agent may be used independently, or 2 or more types may be used together.

  If the content of the thermally decomposable foaming agent in the foamable raw material composition is small, the foaming ratio of the foamed sheet does not increase and the apparent density becomes high, and the repulsive force of the foamed sheet may be high. And the apparent density of the foam sheet is reduced, the compression set is increased, the elastic recovery from the compressed state of the foam sheet is reduced, and the laminate sheet is excellent for a long time when used as a sealing material. Since sealability may not be maintained, 3 to 25 parts by weight is preferable and 5 to 20 parts by weight is more preferable with respect to 100 parts by weight of the total amount of synthetic resin and rubber.

  Moreover, what is necessary is just to adjust suitably according to the characteristic of a synthetic resin or rubber | gum as an irradiation amount of ionizing radiation, 0.5-10 Mrad is preferable and 0.7-5.0 Mrad is more preferable.

  When the foamable resin sheet produced by the production method of (1) above is used, the foamable sheet is produced by heating the foamable resin sheet and crosslinking the foamable resin sheet or after crosslinking. What is necessary is just to use a foaming resin sheet manufactured with the manufacturing method of said (2), and just to heat and foam a foaming resin sheet and to manufacture a foaming sheet.

  Next, a synthetic resin film is peelably laminated on one surface of the foamed sheet to produce a laminated sheet. The method of laminating the synthetic resin film on one side of the foam sheet so as to be peelable is not particularly limited. For example, a method of extruding and laminating the synthetic resin film on one side of the foam sheet, If the foamed sheet has self-adhesive properties, the synthetic resin film is laminated on one side of the foamed sheet and the roll is used to attach the synthetic resin film to the foamed sheet. The method of laminating | stacking on one surface so that peeling is possible, etc. are mentioned.

  Since the laminated sheet of the present invention includes the acrylonitrile-butadiene rubber foamed sheet as described above, when used as a sealing material, it exhibits excellent sealing properties due to excellent elastic recovery.

  Furthermore, the laminated sheet of the present invention is formed by punching the laminated sheet into a desired shape because a synthetic resin film having a predetermined tensile strength, tensile elongation at break and tensile elastic modulus is laminated on one side of the foam sheet. When producing this sealing material, almost no burrs or cutting wastes are generated, and the desired shape can be accurately punched. Therefore, the obtained sealing material has a desired shape suitable for the sealing portion, and there is no deterioration in sealing performance due to the attachment of burrs and cutting waste to the surface, and the laminated sheet of the present invention is stamped and formed. The sealing material thus obtained has excellent sealing properties.

  As described above, the laminated sheet of the present invention is formed by punching because a synthetic resin film having a predetermined tensile strength, tensile breaking elongation and tensile elastic modulus is detachably laminated on one surface of an acrylonitrile-butadiene rubber foamed sheet. This makes it possible to produce a sealing material with an exact shape that fits the seal part, and hardly generates burrs or cutting waste during stamping and seals the surface of the resulting sealing material by burrs or cutting waste. The sealing performance of the material does not deteriorate, and therefore a sealing material having excellent sealing performance can be easily manufactured from the laminated sheet of the present invention by punching.

Example 1
100 parts by weight of acrylonitrile-butadiene rubber (trade name “Nipol 1052J” manufactured by Nippon Zeon Co., Ltd.), 18 parts by weight of azodicarbonamide (trade name “SO-L” manufactured by Otsuka Chemical Co., Ltd.), and phenolic antioxidant (manufactured by Adekastab Co., Ltd.) Name “Adeka Stub AO-60”) A foamable raw material composition containing 0.5 parts by weight is supplied to an extruder, melt-kneaded, extruded from the extruder, and has a thickness of 1.7 mm and a long foaming property. A resin sheet was obtained.

The foamable resin sheet was crosslinked by irradiating the obtained foamable resin sheet with 1.8 Mrad of an electron beam at an acceleration voltage of 500 keV. Thereafter, the foamable resin sheet is supplied into a foaming furnace and heated to 240 ° C. to foam the foamable resin sheet. The foamed resin sheet has a thickness of 5.0 mm and a long foam sheet (75% compressive strength in the thickness direction: 160 kPa, closed cell ratio: 93%, apparent density: 32 kg / m ³ ).

  Next, after superposing a long linear low-density polyethylene film (trade name “UB-1” manufactured by Tamapoly Co., Ltd.) having a thickness of 80 μm on one surface of the long foam sheet, the above-mentioned A foamed sheet was supplied between a pair of rolls and pressed in the thickness direction, and a linear low density polyethylene film was peelably laminated on one surface of the foamed sheet to obtain a laminated sheet.

  The linear low density polyethylene film of the laminated sheet has a tensile strength in the extrusion direction of 43 MPa, a tensile strength in the direction orthogonal to the extrusion direction of 37 MPa, a tensile breaking elongation in the extrusion direction of 660%, and orthogonal to the extrusion direction. The tensile elongation at break in the direction was 810%, the tensile modulus in the extrusion direction was 320 MPa, and the tensile modulus in the direction perpendicular to the extrusion direction was 380 MPa. In any direction, the linear low density polyethylene film had a tensile strength of 43 MPa or less, a tensile elongation at break of 660% or more, and a tensile elastic modulus in the extrusion direction of 380 MPa or less.

(Example 2)
100 parts by weight of acrylonitrile-butadiene rubber (trade name “JSRN220S” manufactured by JSR), 14 parts by weight of azodicarbonamide (trade name “SO-L” manufactured by Otsuka Chemical Co., Ltd.), and a phenolic antioxidant (trade name “manufactured by Adeka Stub”) Adeka Stub AO-60 ") A foamable raw material composition containing 0.5 parts by weight is supplied to an extruder, melt-kneaded and extruded from the extruder to obtain a long foamed resin sheet having a thickness of 1.9 mm. Obtained.

The foamable resin sheet was crosslinked by irradiating the resultant foamable resin sheet with 1.7 Mrad of an electron beam at an acceleration voltage of 500 keV. Thereafter, the foamable resin sheet is supplied into a foaming furnace and heated to 240 ° C. to foam the foamable resin sheet. The foamed resin sheet has a thickness of 5.0 mm and a long foam sheet (75% compressive strength in the thickness direction: 180 kPa, closed cell ratio: 95%, apparent density: 50 kg / m ³ ).

  Next, after laminating a long ethylene-vinyl acetate copolymer film (trade name “AV-51”, manufactured by Tamapoly Co., Ltd.) having a thickness of 100 μm on one surface of the long foam sheet, the above-mentioned The foamed sheet was supplied between a pair of rolls and pressed in the thickness direction, and an ethylene-vinyl acetate copolymer film was peelably laminated on one surface of the foamed sheet to obtain a laminated sheet.

  The ethylene-vinyl acetate copolymer film of the laminated sheet has a tensile strength in the extrusion direction of 25 MPa, a tensile strength in the direction orthogonal to the extrusion direction of 20 MPa, a tensile elongation at break in the extrusion direction of 360%, and orthogonal to the extrusion direction. The tensile elongation at break in the direction of stretching was 660%, the tensile modulus of elasticity in the extrusion direction was 170 MPa, and the tensile modulus of elasticity in the direction perpendicular to the extrusion direction was 210 MPa. In any direction, the ethylene-vinyl acetate copolymer film had a tensile strength of 25 MPa or less, a tensile elongation at break of 360% or more, and a tensile elastic modulus in the extrusion direction of 210 MPa or less.

(Comparative Example 1)
A foam sheet having a thickness of 5.0 mm (75% compression strength in the thickness direction: 160 kPa, closed cell ratio: 93%, apparent density: 32 kg / m ³ ) was produced in the same manner as in Example 1. Next, after laminating a biaxially stretched polyethylene terephthalate film having a thickness of 38 μm on one surface of the foam sheet (product name “Embret S” manufactured by Unitika Ltd.), the foam sheet is placed between a pair of rolls. And a biaxially stretched polyethylene terephthalate film was peelably laminated on one surface of the foamed sheet by pressing in the thickness direction to obtain a laminated sheet.

  The biaxially stretched polyethylene terephthalate film of the laminated sheet has a tensile strength in the extrusion direction of 215 MPa, a tensile strength in the direction orthogonal to the extrusion direction of 228 MPa, a tensile breaking elongation in the extrusion direction of 171%, and a direction orthogonal to the extrusion direction. The tensile elongation at break was 144%, the tensile modulus in the extrusion direction was 3510 MPa, and the tensile modulus in the direction perpendicular to the extrusion direction was 3640 MPa.

(Comparative Example 2)
A foam sheet having a thickness of 5.0 mm (75% compression strength in the thickness direction: 180 kPa, closed cell ratio: 95%, apparent density: 50 kg / m ³ ) was produced in the same manner as in Example 2. Next, after superposing a long unstretched polypropylene film (product name “RO12” manufactured by Santox Co., Ltd.) having a thickness of 60 μm on one surface of the foam sheet, the foam sheet is supplied between a pair of rolls. Then, it was pressed in the thickness direction, and an unstretched polypropylene film was peelably laminated on one surface of the foamed sheet to obtain a laminated sheet.

  The unstretched polypropylene film of the laminated sheet has a tensile strength in the extrusion direction of 50 MPa, a tensile strength in the direction orthogonal to the extrusion direction of 40 MPa, a tensile breaking elongation in the extrusion direction of 500%, and a tensile strength in the direction orthogonal to the extrusion direction. The elongation at break was 50%, the tensile modulus in the extrusion direction was 1350 MPa, and the tensile modulus in the direction perpendicular to the extrusion direction was 1350 MPa.

  The punchability of the obtained laminated sheet and the generation of burrs and cutting waste were evaluated in the following manner, and the results are shown in Table 1.

(Punchability)
Planar circular test pieces having a diameter of 2 mm, 4 mm, and 6 mm were punched from the obtained laminated sheets. The resulting test piece was measured diameter L ₁ of the specimen in the portion provided in most deformed when viewed from a plane, the deformation ratio based on the diameter of Uchinuko it and test specimens as L ₂ in the following formula The deformation rate was calculated and used as an index of punchability.
Deformation rate (%) = 100 × | L ₂ −L ₁ | / L ₂

(Generation of burrs and cutting waste)
When measuring the punchability, visually check whether burrs or cutting debris has been generated. If no burrs or cutting debris has been generated, “○”, if burrs or debris have been generated. Was evaluated as “×”.

Claims (1)

A laminated sheet in which a synthetic resin film is releasably laminated on one surface of an acrylonitrile-butadiene rubber foamed sheet, the synthetic resin film having a tensile strength of 80 MPa or less, a tensile breaking elongation of 250% or more, and a tensile elastic modulus Is a laminated sheet characterized by being 500 MPa or less.