CN104774570A - Double-faced bonding piece - Google Patents

Abstract

The invention relates to a double-faced bonding piece which is good in bonding reliability. The double-faced bonding piece comprises a foaming substrate, a first adhesive layer arranged on a first surface of the foaming substrate, and a second adhesive layer arranged on a second surface of the foaming substrate. The thickness of the foaming substrate is smaller than 1000 [mu]m, the aspect ratio (CD/VD) of an average bubble diameter in the width direction (CD) to an average bubble diameter in the thickness direction (VD) is smaller than 3, and the aspect ratio (MD/CD) of an average bubble diameter in the vertical direction (MD) to an average bubble diameter in the width direction (CD) is larger than 1.

Description

Double-sided adhesive sheet

Technical field

The present invention relates to the double-sided adhesive sheet with foam base material.

Background technology

Generally speaking, tackiness agent (also referred to as pressure-sensitive adhesive, lower with) in the state of soft solid (viscoelastic body), and has and utilizes pressure to be glued to character on adherend simply in the temperature range of near room temperature.Utilize such character, tackiness agent is such as to be provided with form widespread use in order to objects such as engaging, fix in various field of the band base material double-sided adhesive sheet of binder layer on the two sides of base material.

As the base material in above-mentioned band base material double-sided adhesive sheet, generally except plastics film, non-woven fabrics, paper etc., the foam etc. with bubble structure can also be used.Use the double-sided adhesive sheet of above-mentioned foam (band foam base material double-sided adhesive sheet) with using the plastics film without bubble structure or non-woven fabrics etc. as compared with the double-sided adhesive sheet of base material, can be advantageously in impact absorbency, concavo-convex tracing ability, water-repellancy, stopping property etc.Therefore, the joint of the parts in the portable electric appts such as such as mobile phone, smart mobile phone, panel computer, notebook computer can be preferably applied to, fix.As the technical literature relevant to band foam base material double-sided adhesive sheet, patent documentation 1,2 can be enumerated.

Prior art document

Patent documentation

Patent documentation 1: Japanese Unexamined Patent Publication 2010-155969 publication

Patent documentation 2: No. 2005/007731st, International Publication

Summary of the invention

Invent problem to be solved

By the way, double-sided adhesive sheet requires the excellent glueability with adherend.On the other hand, in recent years, consider from the viewpoint such as miniaturization, lightweight of goods, requirement is used for the narrowed width of the double-sided adhesive sheet of the joint of parts etc.When above-mentioned double-sided adhesive sheet being used for the fixing grade of the display panel in portable electric appts, from the viewpoint of giant-screen, the design freedom raising of display panel, the narrowed width of this double-sided adhesive sheet is significant especially.But the double-sided adhesive sheet of narrowed width, due to the reduction etc. of the gluing area with adherend, easily produces from the stripping adherend sometimes.Therefore, even if also obtain sufficient component fixed performance in order to width is narrow, require the performance improving double-sided adhesive sheet further.

Therefore, the object of the present invention is to provide the double-sided adhesive sheet with more excellent gluing reliability.

For the means of dealing with problems

Double-sided adhesive sheet disclosed herein contains foam base material, be arranged on the first binder layer of the first surface of this foam base material and be arranged on second binder layer of second of this foam base material.The thickness of described foam base material is less than 1000 μm.In addition, described foam base material, the aspect ratio (CD/VD) that represents relative to the ratio of the mean air bubble diameter of the thickness direction (VD) of this foam base material with the mean air bubble diameter of the width of this foam base material (CD) for less than 3, be greater than 1 with the aspect ratio (MD/CD) that the mean air bubble diameter of the longitudinal direction of this foam base material (MD) represents relative to the ratio of the mean air bubble diameter of the width (CD) of this foam base material.The double-sided adhesive sheet (band foam base material double-sided adhesive sheet) of described formation can become the double-sided adhesive sheet of the excellent pressing adhesive power of display.The raising of pressing adhesive power can contribute to the raising of gluing reliability.

In an optimal way of double-sided adhesive sheet disclosed herein, the thickness of described double-sided adhesive sheet is more than 100 μm and less than 500 μm.Described double-sided adhesive sheet can become the double-sided adhesive sheet also showing excellent shock-resistance except excellent pressing adhesive power.

In an optimal way of double-sided adhesive sheet disclosed herein, described foam base material is polyolefins foam base material.Double-sided adhesive sheet containing described foam base material can become the double-sided adhesive sheet of the good shock-resistance of display and water-repellancy.

In an optimal way of double-sided adhesive sheet disclosed herein, as described foam base material, the foam base material that such as 25% compressive strength is more than 50kPa preferably can be used.Double-sided adhesive sheet containing described foam base material can become the double-sided adhesive sheet of the better shock-resistance of display.

Double-sided adhesive sheet disclosed herein shows excellent pressing adhesive power, and water-repellancy, excellent impact resistance, therefore, be suitable as such as engaging the double-sided adhesive sheet of the parts of portable electric appts.

Accompanying drawing explanation

Fig. 1 is the cross-sectional schematic of the formation of the double-sided adhesive sheet representing an embodiment.

Photo when Fig. 2 is cross section when utilizing scanning electron microscope (SEM) observation to be cut off by the base material A used in example 1 along the plane parallel with CD with VD.

Photo when Fig. 3 is cross section when utilizing scanning electron microscope (SEM) observation to be cut off by the base material C used in example 3 along the plane parallel with CD with VD.

The explanatory view of the sample for evaluation that Fig. 4 uses when being and representing and measure pressing adhesive power.

Fig. 5 is the explanatory view of the measuring method representing pressing adhesive power.

The explanatory view of the sample for evaluation that Fig. 6 uses when being and representing and evaluate shock-resistance.

Reference numeral

1 double-sided adhesive sheet

11 first binder layers

11A first adhesive face

12 second binder layers

12A second adhesive face

15 foam base materials

15A first surface

15B second

17 release liners

The front of 17A release liner

The back side of 17B release liner

2 double-sided adhesive sheets

21 stainless steels (SUS) plate

21A through hole

22 sheet glass

23 poles

24 brace tables

3 double-sided adhesive sheets

31,32 polycarbonate plates

Embodiment

Below, the preferred embodiment of the present invention is described.In addition, beyond the item mentioned especially in this specification sheets for enforcement the item wanted required for the present invention, can be understood as the design item of the those skilled in the art based on the state of the art.The present invention can implement based on the technology general knowledge of content disclosed in this specification sheets and this area.

In addition, in following accompanying drawing, realize the component of phase same-action, position gives identical symbol and be described, sometimes omit or simplify the explanation repeated.In addition, the embodiment recorded in accompanying drawing carry out signalization to clearly the present invention is described, the earth's surface that is inaccurate is shown as size or the reduced scale of the adhesive sheet of the present invention provided for goods are actual.

In this manual, " tackiness agent " refers to the state in soft solid (viscoelastic body) in the temperature range of near room temperature as previously mentioned, and has the material utilizing pressure can be glued to the character on adherend simply.At this said tackiness agent, as " C.A.Dahlquist; " Adhesion:Fundamental and Practice "; McLaren & Sons; (1966); define P.143 ", generally speaking has satisfied plural modulus in tension E* (1Hz) <10 ⁷dyne/cm ²the material (typically, being the material at 25 DEG C with above-mentioned character) of character.In addition, " base polymer " of tackiness agent refers to the main component (that is, accounting for the composition of more than 50 % by weight of this rubbery polymer) in rubbery polymer (showing the polymkeric substance of caoutchouc elasticity in the temperature range of near room temperature) contained in this tackiness agent.

The double-sided adhesive sheet disclosed herein form of banded isometric size (can for) be configured to containing foam base material be separately positioned on the first surface of this foam base material and first binder layer of second and the second binder layer.Such as, can for having the double-sided adhesive sheet of the form of the cross section structure shown in Fig. 1.The foam base material 15 that this double-sided adhesive sheet 1 has sheet and the first binder layer 11 and the second binder layer 12 supported by the two sides of this base material 15 respectively.More specifically, first surface 15A and second 15B (being non-peel-away) of base material 15 is respectively arranged with the first binder layer 11 and the second binder layer 12.The double-sided adhesive sheet 1 of (on adherend paste before) before using, as shown in Figure 1, can for be the release liner 17 of release surface overlapping and be wound into spiral helicine form with front 17A and back side 17B.In the double-sided adhesive sheet 1 of described form; the surface (the second adhesive face 12A) of the second binder layer 12 is protected by the front 17A of release liner 17, and the surface of the first binder layer 11 (the first adhesive face 11A) is protected by the back side 17B of release liner 17.Or, can be the first adhesive face 11A and the second adhesive face 12A respectively by two panels independently release liner protect form.

As release liner, usual interleaving paper etc. can be used, be not particularly limited.Can use such as: there is on the surface of the liner substrate such as plastics film, paper the release liner of lift-off processing layer, comprise the release liner etc. of the low adhesive materials such as fluoropolymer (tetrafluoroethylene etc.), polyolefin resin (polyethylene, polypropylene etc.).Above-mentioned lift-off processing layer can use such as polysiloxane-based, the stripping treatment agent such as chain alkyl class, fluorine-containing type, moly-sulfide carry out surface treatment to above-mentioned liner substrate and formed.

The mode that double-sided adhesive sheet disclosed herein can be preferably less than 1500 μm with its total thickness is usually implemented.The total thickness of above-mentioned double-sided adhesive sheet typically is more than 50 μm and less than 800 μm, be preferably more than 100 μm and less than 500 μm, be more preferably more than 110 μm and less than 400 μm, more preferably more than 120 μm and less than 300 μm, such as, can be more than 130 μm and less than 280 μm.By the total thickness of double-sided adhesive sheet is set as below above-mentioned higher limit, can be favourable from the aspect such as filming, miniaturization, lightweight, saving resource of goods.In addition, by the total thickness of double-sided adhesive sheet is set as more than above-mentioned lower value, the double-sided adhesive sheet of the excellent shock-resistance of display, water-repellancy can be become.

At this, the total thickness of double-sided adhesive sheet refers to the thickness from an adhesive face to another adhesive face, in the example depicted in figure 1, refers to the thickness t from the first adhesive face 11A to the second adhesive face 12A.Therefore, even the double-sided adhesive sheet of form that such as adhesive face is protected by release liner before pasting on adherend, the thickness of this release liner is also not included in the thickness at this said double-sided adhesive sheet.

< foam base material >

In technology disclosed herein, foam base material refers to the base material possessing the part with bubble (bubble structure), typically refers to containing the base material of thin stratiform foam (foam layer) as integrant.Above-mentioned foam base material can for the base material be in fact only made up of one deck or two-layer above foam layer.Be not particularly limited, as the foam base material in technology disclosed herein, preferably can adopt the foam base material of individual layer (one deck).

The thickness of foam base material can according to the intensity of this double-sided adhesive sheet or the suitably setting such as flexibility, application target.From the viewpoint of the thickness easily guaranteeing the binder layer that can play required adhesion characteristic, usually the thickness of foam base material is set as that less than 1000 μm is suitable, be preferably less than 500 μm, be more preferably less than 300 μm, be such as less than 250 μm, typically be less than 200 μm.The foam base material of thickness less than 180 μm can be used.In addition, consider from viewpoints such as the shock-resistance of double-sided adhesive sheet, resistance to rebound resiliences, the thickness of foam base material is set as more than 30 μm is suitable, be preferably more than 50 μm, be more preferably more than 60 μm (such as more than 80 μm).When the surface shape (can for curved surface, have the surface etc. of the discrepancy in elevation) that this said resistance to rebound resilience refers to along adherend makes above-mentioned double-sided adhesive sheet recoverable deformation, resist the performance (that is, tolerating the performance of the screen resilience of double-sided adhesive sheet) that this double-sided adhesive sheet wants to return to the screen resilience of original form thus the shape after making this double-sided adhesive sheet keep above-mentioned recoverable deformation.

The material of foam base material is not particularly limited.Usually, the foam base material preferably containing the foam layer formed by the foam (plastic foam material) of plastic material.Plastic material (being the implication comprising elastomeric material) for the formation of plastic foam material is not particularly limited, and suitably can select from known plastic material.Plastic material can be used alone a kind of or appropriately combined use is two or more.

As the concrete example of plastic foam material, can enumerate: the polyolefin resin foam such as foam polyethylene, polypropylene expanded body; The polyester resin foaies such as polyethylene terephthalate foam, PEN foam, polybutylene terephthalate foam; The polyvinyl chloride resin foaies such as foam polyvinyl chloride body; Vinyl-acetic ester resin foam body; Polyphenylene sulfide foam; The amides foamed resins such as polymeric amide (nylon) foamed resin, Wholly aromatic polyamide (Aramid) foamed resin; Polyimide based resin foam; Polyether-ether-ketone (PEEK) foam; The styrene resin foaies such as foamed polystyrene body; The urethane based resin foaies such as urethane resin foam; Deng.In addition, as plastic foam material, also the rubber resin foaies such as neoprene latex foam can be used.

As preferred foam, polyolefin resin foam can be illustrated.As the plastic material (that is, polyolefin resin) forming said polyolefins class foam, known or usual various polyolefin resins can be used without particular limitation.Can enumerate such as: polyethylene, polypropylene, ethylene-propylene copolymer, the vinyl-vinyl acetate copolymers etc. such as Low Density Polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene(HDPE) (HDPE), metallocene catalyst linear low density polyethylene.Such polyolefin resin can be used alone a kind of or appropriately combined use is two or more.

As the preference of the foam base material in technology disclosed herein, consider from the viewpoint such as shock-resistance, water-repellancy, the polyethylene kind foam base material be made up of the foam of polythylene resin in fact, the polypropylene-base foam base material etc. be made up of the foam of polypropylene-based resin in fact can be enumerated.At this, using ethene as principal monomer (namely polythylene resin refers to, main component in monomer) resin, except HDPE, LDPE, LLDPE etc., the ethylene-propylene copolymer, vinyl-vinyl acetate copolymer etc. of copolymerization ratios more than 50 % by weight of ethene can also be comprised.Similarly, polypropylene-based resin refers to the resin using propylene as principal monomer.As the foam base material in technology disclosed in this, polyethylene kind foam base material preferably can be adopted.

The manufacture method of above-mentioned plastic foam material (typically being polyolefins foam) is not particularly limited, and can be manufactured by known method.Such as, can by comprising the method manufacture of the forming process of above-mentioned plastic material or above-mentioned plastic foam material, cross-linking process step and foamed process.In addition, stretching process can be comprised as required.

As the method making above-mentioned plastic foam material crosslinked, the chemical crosslink technique such as using organo-peroxide etc. or the crosslinking by ionizing radiation method etc. of irradiating ionizing rays can be enumerated.These Combination of Methods can be used.As above-mentioned ionizing rays, electron rays, alpha-ray, β ray, gamma-rays etc. can be illustrated.The irradiation of above-mentioned ionizing rays is not particularly limited, and can suitably regulate to obtain the physical property required by above-mentioned plastic foam material such as aimed graft degree, flexibility.

The mean air bubble diameter (proper sphere conversion) of above-mentioned foam base material (such as polyolefins foam base material) is not particularly limited, usually more than 10 μm are preferably and less than 500 μm, be more preferably more than 15 μm and less than 300 μm, more preferably more than 20 μm and less than 200 μm, such as, be preferably more than 25 μm and less than 100 μm.By the mean air bubble diameter (proper sphere conversion) of above-mentioned foam base material is adjusted to more than 10 μm, there is the tendency improving shock-resistance.On the other hand, by the mean air bubble diameter (proper sphere conversion) of above-mentioned foam base material is adjusted to less than 500 μm, there is the tendency improving water-repellancy.

At this, in this specification sheets, the mean air bubble diameter (proper sphere conversion) of above-mentioned foam base material refers to the value measuring in the following manner and obtain.Namely, the arbitrary cut surface of this foam base material is observed with scanning electron microscope (SEM), then binary conversion treatment carried out to this imagery exploitation image processing software and be separated into bubble portion and the part beyond it (such as plastic resin portion), and each bubble area is measured for above-mentioned bubble portion.Then, calculate the mean value of each diameter when this bubble area being scaled proper circle area, it can be used as the mean air bubble diameter (proper sphere conversion) of foam base material.As SEM, the device name " S-4800 " that high-tech company of Hitachi can be used to manufacture or the product suitable with it.As image processing software, the goods name manufactured by US National health research " IMAGE J " or the product suitable with it can be used.

It is suitable that the mean air bubble diameter (proper sphere conversion) of above-mentioned foam base material is generally less than 50% of the thickness of above-mentioned foam base material, is preferably less than 30% (such as less than 10%).By the mean air bubble diameter (proper sphere conversion) of this foam base material is adjusted to less than 50% of the thickness of foam base material, there is the tendency that water-repellancy improves further.

In this specification sheets, the longitudinal direction of above-mentioned foam base material is (also referred to as MD; Lower with) refer to and extrude direction in this foam base material manufacturing process.Be not particularly limited, when above-mentioned foam base material is the form of banded isometric size shape, the MD of this foam base material is usually consistent with this its length direction.In addition, the width of this foam base material is (also referred to as CD; Lower with) refer to and the direction on surface along above-mentioned foam base material orthogonal with above-mentioned MD.In addition, the thickness direction of above-mentioned foam base material is (also referred to as VD; Lower same) refer to and the direction of the surface normal of this foam base material, i.e. self-orthogonal direction each with above-mentioned MD and above-mentioned CD.

In this specification sheets, as the index of the shape of bubble contained in the above-mentioned foam base material of expression, use as shown in the formula " aspect ratio (CD/VD) " that represent relative to the ratio of the mean air bubble diameter of the thickness direction (VD) of this foam base material with the mean air bubble diameter of the width of this foam base material (CD) shown in (1) with as shown in the formula " aspect ratio (MD/CD) " that represent relative to the ratio of the mean air bubble diameter of the width (CD) of this foam base material with the mean air bubble diameter of the longitudinal direction of this foam base material (MD) shown in (2).

The mean air bubble diameter (1) of the mean air bubble diameter/VD of aspect ratio (CD/VD)=CD

The mean air bubble diameter (2) of the mean air bubble diameter/CD of aspect ratio (MD/CD)=MD

At this, in this specification sheets, " mean air bubble diameter of MD " is defined as the following mean air bubble diameter measured.

Namely, by plane parallel with MD with VD on the approximate central part edge of its CD for above-mentioned foam base material (namely, the plane that the direction of vertical line is consistent with CD) cut off, and utilize above-mentioned scanning electron microscope (SEM) central part to this cut surface to take pictures.

Then, by the image printing of shooting on the paper of A4 size, the straight line of the length 60mm that standardized bar is parallel with MD on image.Now, regulate the magnification of above-mentioned electron microscope, make on the straight line of 60mm, there are about 10 ~ about 20 bubbles.

By the number of bubbles that the above-mentioned straight line of visual counting exists, and based on following formula (3), obtain the mean air bubble diameter of the MD of above-mentioned foam base material.

Mean air bubble diameter (μm)=60 (mm) × 10 of MD ³/ (number of bubbles (individual) × magnification) (3)

In addition, " mean air bubble diameter of CD " is defined as the following mean air bubble diameter measured.

That is, above-mentioned foam base material is cut off along the plane parallel with CD with VD (that is, the direction of vertical line and the consistent plane of MD), and utilize above-mentioned scanning electron microscope (SEM) central part to this cut surface to take pictures.

Then, by the image printing of shooting on the paper of A4 size, the straight line of the length 60mm that standardized bar is parallel with CD on image.Now, regulate the magnification of above-mentioned electron microscope, make on the straight line of 60mm, there are about 10 ~ about 20 bubbles.

By the number of bubbles that the above-mentioned straight line of visual counting exists, and based on following formula (4), obtain the mean air bubble diameter of the CD of above-mentioned foam base material.

Mean air bubble diameter (μm)=60 (mm) × 10 of CD ³/ (number of bubbles (individual) × magnification) (4)

In addition, " mean air bubble diameter of VD " is defined as the following mean air bubble diameter measured.

That is, by the main points same with when calculating the mean air bubble diameter of above-mentioned CD, above-mentioned foam base material is cut off along the face parallel with CD with VD, utilizes scanning electron microscope to take pictures to this cut surface, and print the image obtained.Then, image is drawn and three straight lines of on CD the quartern respectively parallel with VD from a surface of double-sided adhesive sheet to another surface.Measure the length of each straight line, calculate their aggregate value.In addition, by the number of bubbles that the above-mentioned straight line of visual counting exists, and obtain the mean air bubble diameter of the VD of above-mentioned foam base material based on following formula (5).

The total (mm) × 10 of the length of three straight lines on mean air bubble diameter (μm)=image of VD ³/ (number of bubbles (individual) × magnification) (5)

In addition, when drawing straight line, make straight line become as far as possible to run through bubble and not with the state of bubble point cantact.When part bubble contacts with rectilinear point, it is 1 by this bubble counting.In addition, under the state that the both ends of straight line are not run through bubble and are positioned at bubble, it is 0.5 by this bubble counting.

The mean air bubble diameter of all directions of above-mentioned MD, CD and VD can control by regulating the composition of the condition of the manufacturing process of such as foam base material (foamed process, stretching process etc.), foam base material (usage quantity etc. of whipping agent).Be not particularly limited, when above-mentioned foam base material is formed as the form of long size shape being utilized by plastics forming body forcing machine to carry out stretching, there is tendency that the direction of the longest mean air bubble diameter of the bubble representing contained in this foam base material is consistent with the length direction (i.e. MD) of this foam base material usually.

The aspect ratio (CD/VD) of above-mentioned foam base material is preferably less than 3.Above-mentioned aspect ratio (CD/VD) is more preferably less than 2.8, and more preferably less than 2.5, be such as preferably less than 2.3.In addition, above-mentioned aspect ratio (CD/VD) is preferably greater than 1, is more preferably more than 1.3, typically is more than 1.5, such as, be preferably more than 1.7.By above-mentioned aspect ratio (CD/VD) is adjusted to below above-mentioned higher limit, the double-sided adhesive sheet with above-mentioned foam base material can show high pressing adhesive power.As a reason of pressing adhesive power raising like this, think, because of passing through to control the bubble shape of above-mentioned foam base material to obtain the scope of above-mentioned aspect ratio (CD/VD), in above-mentioned foam base material, stress when being extruded by double-sided adhesive sheet through-thickness to be dispersed in more.In addition, being greater than above-mentioned lower value by above-mentioned aspect ratio (CD/VD) being adjusted to, the tendency that the flexibility with the double-sided adhesive sheet using above-mentioned foam base material increases, concavo-convex tracing ability, shock-resistance can be improved.

The aspect ratio (MD/CD) of above-mentioned foam base material is preferably greater than 1.Above-mentioned aspect ratio (MD/CD) is more preferably more than 1.4, and more preferably more than 1.6, typically be more than 2, such as, be preferably more than 2.3.In addition, above-mentioned aspect ratio (MD/CD) is preferably less than 5, is more preferably less than 4, and more preferably less than 3.5, be such as preferably less than 3.Being greater than above-mentioned lower value by above-mentioned aspect ratio (MD/CD) being adjusted to, the operability of the double-sided adhesive sheet using above-mentioned foam base material can be improved.In addition, by above-mentioned aspect ratio (MD/CD) is adjusted to below above-mentioned higher limit, the water-repellancy of the double-sided adhesive sheet using above-mentioned foam base material can be improved.

The density (apparent density) of above-mentioned foam base material is not particularly limited, such as, be preferably 0.2g/cm ³above and 0.6g/cm ³below.The density of above-mentioned foam base material is more preferably 0.25g/cm ³above and 0.55g/cm ³below, 0.3g/cm is preferably greater than further ³and 0.5g/cm ³below, be such as 0.35g/cm ³above and 0.5g/cm ³below.By being 0.2g/cm by Auto-regulating System of Density of Heavy Medium ³above, there is the tendency of raising of the raising of the intensity (and then intensity of double-sided adhesive sheet) realizing foam base material, shock-resistance, operability.On the other hand, by being 0.6g/cm by Auto-regulating System of Density of Heavy Medium ³below, there is the tendency of concavo-convex tracing ability, resistance to rebound resilience, water-repellancy raising.In addition, the density (apparent density) of foam base material can by such as measuring based on the method for JIS K 6767.

The tensile strength (tensile strength) of above-mentioned foam base material (such as polyolefins foam base material) is not particularly limited.Such as, longitudinally the tensile strength of (MD) is preferably more than 1MPa and below 30MPa (more preferably more than 2MPa and below 20MPa, further preferably more than 2.5MPa and below 10MPa, typically be more than 3MPa and below 7MPa).In addition, the tensile strength of width (CD) is preferably more than 1MPa and below 30MPa (more preferably more than 3MPa and below 20MPa, further preferably more than 4MPa and below 15MPa, typically be more than 4.5MPa and below 10MPa).By being adjusted to the tensile strength of more than above-mentioned lower value, when peeling off double-sided adhesive sheet in order to recovery part, base material (and then double-sided adhesive sheet) can be shown and easily peel off and the excellent operability (doing over again property) such as can not to tear.On the other hand, by being adjusted to the tensile strength of below above-mentioned higher limit, shock-resistance, discrepancy in elevation tracing ability can be improved.The tensile strength (longitudinal tensile strength, the tensile strength of width) of foam base material measures according to JIS K6767.The tensile strength of above-mentioned foam base material can pass through the such as control such as degree of crosslinking, density.

25% compressive strength of above-mentioned foam base material (such as polyolefins foam base material) is not particularly limited, such as, be preferably more than 50kPa and below 1000kPa.25% compressive strength of above-mentioned foam base material is more preferably and is greater than 60kPa and below 1000kPa, more than 75kPa and below 1000kPa, more than 75kPa and below 500kPa, more preferably more than 80kPa and below 500kPa, typically be more than 90kPa and below 300kPa, such as, be preferably more than 100kPa and below 250kPa.At this, 25% compressive strength of above-mentioned foam base material refers to overlapping for this foam base material also past with dull and stereotyped folder with the thickness reaching about 25mm, compressed be equivalent to initial thickness 25% amount of thickness time load, that is, the load when thickness being compressed to this base material is 75% of initial thickness.By 25% compressive strength is adjusted to more than 50kPa, the tendency that the shock-resistance with double-sided adhesive sheet improves, in addition, can improve the dimensional stability adding man-hour.On the other hand, by 25% compressive strength is adjusted to below 1000kPa, resistance to rebound resilience, discrepancy in elevation tracing ability can be improved.25% compressive strength of foam base material measures according to JIS K6767.25% compressive strength of above-mentioned foam base material can pass through the such as control such as degree of crosslinking, density.

The heated dimensions velocity of variation (90 DEG C of heated dimensions velocity of variation (MD)) of the MD at 90 DEG C of above-mentioned foam base material (such as polyolefins foam base material) is not particularly limited, such as, to be preferably more than-10% and less than 10%.90 DEG C of heated dimensions velocity of variation (MD) of above-mentioned foam base material to be more preferably more than-5% and less than 5%, more preferably more than-4% and less than 4%.By 90 DEG C of heated dimensions velocity of variation (MD) are adjusted in above-mentioned scope, even if (such as 40 DEG C ~ 90 DEG C) also can suppress expansion, the contraction of the double-sided adhesive sheet with above-mentioned foam base material in high temperature environments, excellent gluing reliability can be shown.

The heated dimensions velocity of variation (90 DEG C of heated dimensions velocity of variation (CD)) of the CD at 90 DEG C of above-mentioned foam base material (such as polyolefins foam base material) is not particularly limited, such as, to be preferably more than-10% and less than 10%.90 DEG C of heated dimensions velocity of variation (CD) of above-mentioned foam base material to be more preferably more than-5% and less than 5%, more preferably more than-4% and less than 4%.By 90 DEG C of heated dimensions velocity of variation (CD) are adjusted in above-mentioned scope, even if (such as 40 DEG C ~ 90 DEG C) also can suppress expansion, the contraction of the double-sided adhesive sheet with above-mentioned foam base material in high temperature environments, excellent gluing reliability can be shown.

90 DEG C of heated dimensions velocity of variation of MD and CD of foam base material, except being set as, except 90 DEG C, measuring according to JIS K 6767 by Heating temperature.

The degree of crosslinking of above-mentioned foam base material (such as polyolefins foam base material) is not particularly limited, such as, be preferably more than 10% and less than 50%.The degree of crosslinking of above-mentioned foam base material is more preferably more than 20% and less than 45%, and more preferably more than 30% and less than 40% (such as more than 32% and less than 40%).

At this, the value that the degree of crosslinking in this specification sheets refers to following mensuration and obtains.That is, the test film of about 100mg is got from the foam base material of determination object, and the weight A of accurate weighing test film (mg).Then, this test film is impregnated into the 30cm of 120 DEG C ³in dimethylbenzene and after placing 24 hours, with 200 object metal mesh filters.Get the insoluble composition on wire netting and vacuum-drying, and the weight B (mg) of this insoluble composition of accurate weighing.Degree of crosslinking is calculated by following formula (6) by the value obtained.

Linking agent (%)=(B/A) × 100 (6)

In above-mentioned foam base material, the various additives such as weighting agent (inorganic filler, organic filler etc.), antiaging agent, antioxidant, UV light absorber, antistatic agent, lubricant, softening agent, fire retardant, tensio-active agent can be coordinated as required.

Foam base material in technology disclosed herein, in order to make the double-sided adhesive sheet with this foam base material show required designability or optical characteristics (such as, opacifying property, light reflective etc.), can carry out painted.This is painted can be used alone a kind of or the two or more known organic or inorganic colourant of appropriately combined use.

Such as, when double-sided adhesive sheet disclosed herein is used for shading purposes, the transmission of visible light of foam base material is not particularly limited, and is preferably more than 0% and less than 15% in the same manner as the transmission of visible light of double-sided adhesive sheet described later, is more preferably more than 0% and less than 10%.In addition, when double-sided adhesive sheet disclosed herein is used for luminous reflectance purposes, the visible reflectance of foam base material is preferably more than 20% and less than 100% in the same manner as the visible reflectance of double-sided adhesive sheet, is more preferably more than 25% and less than 100%.

The transmission of visible light of foam base material can by using spectrophotometer (such as, the spectrophotometer that Co., Ltd. Hitachi's high-tech manufactures, model " U-4100 "), measure under wavelength 550nm and to irradiate from the side, a face of foam base material and the intensity being transmitted to the light of another side, face is obtained.The visible reflectance of foam base material can by using above-mentioned spectrophotometer, measures to irradiate from the side, a face of foam base material and the intensity of the light reflected is obtained under wavelength 550nm.In addition, the transmission of visible light of double-sided adhesive sheet, visible reflectance also can be obtained by same method.

When double-sided adhesive sheet disclosed herein is used for shading purposes, above-mentioned foam base material is preferably colored as black.As black, the L* (lightness) specified by L*a*b* color specification system is preferably less than 35 (such as, 0 ~ 35), is more preferably less than 30 (such as, 0 ~ 30).In addition, a*, b* of being specified by L*a*b* color specification system suitably can select according to the value of L* separately.As a*, b*, be not particularly limited, preferred both sides are the scope of-10 ~ 10 (more preferably-5 ~ 5, further preferred-2.5 ~ 2.5).Such as, preferred a* and b* is 0 or be approximately 0.

In addition, in this specification sheets, L*, a*, b* of being specified by L*a*b* color specification system can measure and try to achieve by using color evaluating (such as, the color evaluating that Minolta company manufactures, trade(brand)name " CR-200 ").In addition, L*a*b* color specification system is the color space that International Commission on Illumination (CIE) was recommended in 1976, refers to the color space being called CIE1976 (L*a*b*) color specification system.In addition, L*a*b* color specification system is specified by JIS Z 8729 in Japanese Industrial Standards.

As the black colorant used when being black by foam substrate coloring, can enumerate such as: carbon black (furnace black, thermally oxidized black, acetylene black, thermals, dim etc.), graphite, cupric oxide, Manganse Dioxide, nigrosine, perylene are black, titanium is black, cyanine is black, gac, ferrite (non magnetic ferrite, magnetic ferrite etc.), magnetite, chromic oxide, ferric oxide, molybdenumdisulphide, chromium complex, composite oxides class black pigment, the organic black pigment of Anthraquinones etc.Consider preferred black colorant as from the viewpoint such as cost, availability, can carbon black be illustrated.The usage quantity of black colorant is not particularly limited, and can suitably be adjusted to the amount can giving required optical characteristics.

When double faced adhesive tape bonding die disclosed herein is used for luminous reflectance purposes, above-mentioned foam base material is preferably colored as white.As white, the L* (lightness) specified by L*a*b* color specification system is preferably more than 87 (such as, 87 ~ 100), is more preferably more than 90 (such as 90 ~ 100).In addition, a*, b* of being specified by L*a*b* color specification system suitably can select according to the value of L* separately.As a*, b*, such as, preferred both sides are the scope of-10 ~ 10 (more preferably-5 ~ 5, further preferred-2.5 ~ 2.5).Such as, preferred a* and b* is 0 or be approximately 0.

As the white color agents used when being white by foam substrate coloring, can enumerate such as: titanium oxide (rutile titanium dioxide, the titanium dioxide such as anatase titanium dioxide), zinc oxide, aluminum oxide, silicon oxide, zirconium white, magnesium oxide, calcium oxide, stannic oxide, barium oxide, Cs2O, yttrium oxide, magnesiumcarbonate, calcium carbonate (light calcium carbonate, water-ground limestone etc.), barium carbonate, zinc carbonate, aluminium hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, pure aluminium silicate, Magnesium Silicate q-agent, Calucium Silicate powder, barium sulfate, calcium sulfate, barium stearate, the flowers of zinc, zinc sulphide, talcum, silicon-dioxide, aluminum oxide, clay, kaolin, titanium phosphate, mica, gypsum, white carbon black, diatomite, wilkinite, lithopone, zeolite, sericite, the Inorganic white tinting materials such as endellite, acrylic resin particle, polystyrene resins particle, polyurethane based resin particle, amides resin particle, polycarbonate resin particle, polysiloxane resin particle, urea air aldehyde resin particle, organic white color agents etc. such as trimeric cyanamide resin particle.The usage quantity of white color agents is not particularly limited, and can suitably be adjusted to the amount can giving required optical characteristics.

Suitable surface treatment can be implemented as required in the surface of foam base material.This surface treatment can for for improving adhering chemistry to adjacent material (such as binder layer) or physical treatment.As described surface-treated example, can enumerate Corona discharge Treatment, chromic acid process, be exposed to ozone, be exposed to flame, uviolizing process, Cement Composite Treated by Plasma, silane coupling agent (priming paint) coating etc.

In technology disclosed herein, the kind being arranged on tackiness agent contained in the first surface of foam base material and first binder layer of second and the second binder layer is not particularly limited.As this tackiness agent, such as can for containing be selected from the various polymkeric substance (binding property polymer) such as acrylic acid or the like, polyester, polyurethanes, polyethers, rubber-like, polysiloxane-based, polyamide-based, fluorine-containing type one or more based on the tackiness agent of polymkeric substance.In a preferred embodiment, the main component of above-mentioned binder layer is acrylic adhesives.Technology disclosed herein can preferably be implemented with the form with the double-sided adhesive sheet of the binder layer be made up of acrylic adhesives in fact.

At this, " acrylic adhesives " refers to the tackiness agent of polymkeric substance (namely the main component in component of polymer accounts for the composition of more than 50 % by weight) based on acrylic polymers." acrylic polymers " refers to the monomer in a part with at least one (methyl) acryl (following; sometimes be referred to as " acrylic monomer ") as the polymkeric substance of main composition monomer component (namely monomer main component accounts for composition more than 50 % by weight in the monomer total amount forming acrylic polymers).In addition, in this specification sheets, " (methyl) acryl " is the implication briefly representing acryl and methacryloyl.Similarly, " (methyl) acrylate " is the implication briefly representing acrylate and methacrylic ester.

Aforesaid propylene acids polymers is typically using (methyl) alkyl acrylate as the polymkeric substance of main composition monomer component.As above-mentioned (methyl) alkyl acrylate, can the preferred compound that represents as shown in the formula (7) of example.

CH ₂＝C(R ¹)COOR ²(7)

At this, the R in above-mentioned formula (7) ¹for hydrogen atom or methyl.R ²for the alkyl of carbonatoms 1 ~ 20.The viewpoint of the tackiness agent that the adhesion characteristic that is easy to get calmly is excellent is considered, preferred R ²for the scope of such carbonatoms (is denoted as C by carbonatoms 2 ~ 14 below sometimes _2-14) (methyl) alkyl acrylate of alkyl.As C _2-14the concrete example of alkyl, can enumerate: ethyl, propyl group, sec.-propyl, normal-butyl, isobutyl-, sec-butyl, the tertiary butyl, n-pentyl, isopentyl, neo-pentyl, n-hexyl, n-heptyl, n-octyl, iso-octyl, 2-ethylhexyl, n-nonyl, different nonyl, positive decyl, isodecyl, n-undecane base, dodecyl, n-tridecane base, n-tetradecane base etc.

In a preferred embodiment, (typically be more than about 50 % by weight and less than about 99.9 % by weight) in the monomer total amount used in the synthesis of acrylic polymers more than about 50 % by weight, more preferably from about more than 70 % by weight (typically be more than about 70 % by weight and less than about 99.9 % by weight), such as more than about 85 % by weight (typically are more than about 85 % by weight and less than about 99.9 % by weight) are by the R be selected from above formula (7) ²for C _2-14(methyl) alkyl acrylate (more preferably (methyl) vinylformic acid C of alkyl _4-10alkyl ester, the one or both particularly preferably in butyl acrylate and 2-EHA) one or more occupy.By being made up of the acrylic polymers obtained such monomer, the tackiness agent of the good adhesion characteristic of display easily can be formed, therefore preferably.

Be not particularly limited, as the acrylic polymers in technology disclosed herein, can preferably use copolymerization to have to have the acrylic polymers of the acrylic monomer of hydroxyl (-OH).As the concrete example of acrylic monomer with hydroxyl, can enumerate: (methyl) vinylformic acid 2-hydroxy methacrylate, (methyl) vinylformic acid 2-hydroxy propyl ester, (methyl) vinylformic acid 3-hydroxy propyl ester, (methyl) vinylformic acid 2-hydroxybutyl, (methyl) vinylformic acid 4-hydroxybutyl, the own ester of (methyl) vinylformic acid 2-hydroxyl, the own ester of (methyl) vinylformic acid 6-hydroxyl, (methyl) vinylformic acid 8-hydroxyl monooctyl ester, (methyl) vinylformic acid 10-hydroxyl ester in the last of the ten Heavenly stems, (methyl) vinylformic acid 12-hydroxylauric ester, (methyl) vinylformic acid (4-hydroxymethylcyclohexyl) methyl esters, polypropylene glycol list (methyl) acrylate, N-hydroxyethyl (methyl) acrylamide, N-hydroxypropyl (methyl) acrylamide etc.Described hydroxy acryl acid class monomer can be used alone one, also can combinationally use two or more.

There is the acrylic polymers of such hydroxy acryl acid class monomer by copolymerization, easily obtain the tackiness agent that balance is excellent, releasable is excellent of bounding force and cohesive force, therefore preferably.As particularly preferred hydroxy acryl acid class monomer, can enumerate: (methyl) hydroxyalkyl acrylates such as (methyl) vinylformic acid 2-hydroxy methacrylate, (methyl) vinylformic acid 2-hydroxy propyl ester, (methyl) vinylformic acid 3-hydroxy propyl ester, (methyl) vinylformic acid 2-hydroxybutyl, (methyl) vinylformic acid 4-hydroxybutyl.Such as, (methyl) hydroxyalkyl acrylate of the straight chained alkyl that can preferably use the alkyl in above-mentioned hydroxyalkyl to be carbonatoms 2 ~ 4.

Such hydroxy acryl acid class monomer preferably for the synthesis of acrylic polymers monomer total amount in more than about 0.001 % by weight and use in the scope of less than about 10 % by weight.Thus, the double-sided adhesive sheet with higher level balance those bounding force and cohesive force can be realized.By the usage quantity of hydroxy acryl acid class monomer being set as more than about 0.01 % by weight and less than about 5 % by weight (such as more than about 0.05 % by weight and less than about 2 % by weight), better result can be reached.Or the acrylic polymers in technology disclosed herein can be the acrylic polymers that non-copolymerization has hydroxy acryl acid class monomer.

Significantly not damaging in the scope of effect of the present invention, in the acrylic polymers in technology disclosed herein, copolymerization monomer other than the above (other monomer) can be had.Described monomer can in order to such as regulate the second-order transition temperature of acrylic polymers, regulate the objects such as bond properties (such as separability) and use.Such as, as the cohesive force of tackiness agent, the monomer of thermotolerance can be improved, can enumerate containing sulfonic group monomer, phosphorous acid-based monomers, cyano-containing monomer, vinyl ester, aromatic ethenyl compound etc.In addition, as the functional group that can become crosslinked basic point can be introduced or contribute to improving the monomer of adhesive power in acrylic polymers, can enumerate carboxyl group-containing monomer, containing anhydride group monomer, amide-containing monomer, emulsion stability, containing imide monomer, containing epoxy based monomers, (methyl) acryloyl morpholine, vinyl ethers etc.Such as, preferred copolymerization has carboxyl group-containing monomer as the acrylic polymers of other monomer above-mentioned.

As containing sulfonic group monomer, can illustrate: styrene sulfonic acid, allyl sulphonic acid, 2-(methyl) acrylamide-2-methylpro panesulfonic acid, (methyl) acryamidopropanesulfonic acid, (methyl) sulfopropyl acrylate, (methyl) propane sulfonic acid, sodium vinyl sulfonate etc.

As phosphorous acid-based monomers, can illustrate: acryloyl phosphoric acid 2-hydroxy methacrylate.

As cyano-containing monomer, can illustrate: vinyl cyanide, methacrylonitrile etc.

As vinyl ester, can illustrate such as: vinyl-acetic ester, propionate, vinyl laurate etc.

As aromatic ethenyl compound, vinylbenzene, chloro-styrene, 1-chloro-4-methyl-benzene, alpha-methyl styrene, other substituted phenylethylene etc. can be illustrated.

In addition, as carboxyl group-containing monomer, can illustrate: vinylformic acid, methacrylic acid, (methyl) carboxyethyl acrylates, (methyl) vinylformic acid carboxyl pentyl ester, methylene-succinic acid, toxilic acid, fumaric acid, β-crotonic acid, iso-crotonic acid etc.

As containing anhydride group monomer, can enumerate: the acid anhydrides etc. of maleic anhydride, itaconic anhydride, above-mentioned carboxyl group-containing monomer.

As amide-containing monomer, can illustrate: acrylamide, Methacrylamide, acrylamide, NVP, N, N-DMAA, N, N-dimethylmethacryl amide, N, N-acrylamide, N, N-diethyhnethacrylamide, N, N '-methylene-bisacrylamide, N, N-dimethylaminopropylacryl acid amides, N, N-dimethylaminopropyl Methacrylamide, diacetone-acryloamide(DAA) etc.

As emulsion stability, can illustrate: (methyl) acrylate, (methyl) vinylformic acid N, N-dimethylamino ethyl ester, (methyl) vinylformic acid N, N-dimethylamino propyl ester etc.

As containing imide monomer, can illustrate: N-cyclohexylmaleimide, isopropylmaleimide, N-N-cyclohexylmaleimide, clothing health imide etc.

As containing epoxy based monomers, can illustrate: (methyl) glycidyl acrylate, (methyl) vinylformic acid methylglycidyl esters, allyl glycidyl ether etc.

As vinyl ethers, can illustrate: methylvinylether, ethyl vinyl ether, IVE etc.

" other monomer " like this can be used alone one, also can combinationally use two or more, content as a whole, be preferably set to less than about 40 % by weight in for the synthesis of the monomer total amount of acrylic polymers (typically be more than about 0.001 % by weight and less than about 40 % by weight), more preferably less than about 30 % by weight are set as (typically be more than about 0.01 % by weight and less than about 30 % by weight, such as more than about 0.1 % by weight and less than about 10 % by weight).When using carboxyl group-containing monomer as other monomer above-mentioned, its content such as can be set as more than 0.1 % by weight and less than 10 % by weight in above-mentioned monomer total amount, usually more than 0.2 % by weight is set as and less than 8 % by weight, such as more than 0.5 % by weight and less than 5 % by weight be suitable.In addition, when using vinyl ester (such as vinyl-acetic ester) as other monomer above-mentioned, its content such as can be set as more than 0.1 % by weight and less than 20 % by weight in above-mentioned monomer total amount, is usually set as more than 0.5 % by weight and less than 10 % by weight is suitable.

The copolymerization composition of aforesaid propylene acids polymers is suitable to make the second-order transition temperature of this polymkeric substance (Tg) be that the mode of less than-15 DEG C (typically being more than-70 DEG C and less than-15 DEG C) carries out designing, be preferably less than-25 DEG C (such as more than-60 DEG C and less than-25 DEG C), be more preferably less than-40 DEG C (such as more than-60 DEG C and less than-40 DEG C).When the Tg of acrylic polymers is too high, the bounding force of the tackiness agent likely containing polymkeric substance based on this acrylic polymers (bounding force under such as low temperature environment, bounding force etc.) to uneven surface easily declines.When the Tg of acrylic polymers is too low, likely the curved surface tackiness of above-mentioned tackiness agent easily declines or releasable easily declines (such as, produce generation of adhesive deposit).

The Tg of acrylic polymers can be regulated by appropriate change monomer composition (i.e. the kind of the monomer used in the synthesis of this polymkeric substance, usage quantity than).At this, the Tg of acrylic polymers refers to the value that the Tg of homopolymer (homopolymer) and the weight fraction (copolymerization ratios of weight basis) of this monomer based on each monomer forming this polymkeric substance are obtained by Fox formula.As the Tg of homopolymer, the value recorded in known data can be adopted.

In technology disclosed herein, as the Tg of above-mentioned homopolymer, adopt following value particularly.

For the Tg of the homopolymer beyond above-mentioned illustration, the numerical value recorded in Polymer Handbook (polymer handbook) (the 3rd edition, Wiley & Sons, Inc, 1989) can be adopted.

When also not recording in Polymer Handbook (the 3rd edition, Wiley & Sons, Inc, 1989), adopt the value obtained by following measuring method.

Specifically, in the reactor with thermometer, agitator, nitrogen introducing tube and reflux condensing tube, drop into 100 weight parts monomers, 0.2 weight part Diisopropyl azodicarboxylate and the 200 weight parts ethyl acetate as polymer solvent, and while passing into nitrogen, stir 1 hour.Like this by after the oxygen removing in polymerization system, be warmed up to 63 DEG C and react 10 hours.Then, cool to room temperature, obtains the homopolymer solution of solid component concentration 33 % by weight.Then, this homopolymer solution casting is applied on release liner, dry and make the sample (homopolymer of sheet) that thickness is about 2mm.Be the discoid of diameter 7.9mm by this sample stamping-out, clamp with parallel plate, (TA Instrument Japan company manufactures to use test for viscoelastic machine, model " ARES "), while the shear strain applying frequency 1Hz, in the temperature range of-70 DEG C ~ 150 DEG C, measure visco-elasticity by shear mode with the heat-up rate of 5 DEG C/min, and shearing out-of-phase modulus G will be corresponded to " summit temperature temperature (G " curve very big time temperature) as the Tg of homopolymer.

Tackiness agent in technology disclosed herein is preferably to make the shearing out-of-phase modulus G of this tackiness agent " summit temperature be that the mode of less than-10 DEG C (typically being more than-40 DEG C and less than-10 DEG C) designs.Such as, preferably to make above-mentioned summit temperature be more than-35 DEG C and the tackiness agent of the patten's design of less than-15 DEG C.Shear out-of-phase modulus G " summit temperature can by being the discoid of diameter 7.9mm by the sheet tackiness agent stamping-out of thickness 1mm; clamp with parallel plate; use above-mentioned test for viscoelastic machine (TA Instrument Japan company manufactures; model " ARES "); while the shear strain applying frequency 1Hz with the heat-up rate of 5 DEG C/min in the temperature range of-70 DEG C ~ 150 DEG C by shear mode mensuration out-of-phase modulus G " temperature dependency, obtain corresponding to its summit temperature (G " curve very big time temperature) grasp.

In addition, the shearing out-of-phase modulus G of acrylic polymers " summit temperature can be formed (that is, the kind of the monomer used in the synthesis of this polymkeric substance, usage quantity than) by the monomer of this acrylic polymers of appropriate change and regulate.The shearing out-of-phase modulus G of tackiness agent " summit temperature can consist of (that is, the kind of the monomer used in the synthesis of this polymkeric substance, usage quantity than) the monomer of appropriate change acrylic polymers, the kind, usage quantity etc. of the tackifier of use whether, when using of tackifier described later regulate.

The method obtaining described acrylic polymers is not particularly limited, and can suitably adopt solution polymerization process, emulsion polymerization, mass polymerization, suspension polymerization etc. as the known various polymerization processs of the synthetic method of acrylic polymers.Such as, preferably solution polymerization process can be adopted.As monomer supply method when carrying out solution polymerization, fed batch mode, continuously supply (droppings) mode, the substep once supplied by whole raw material monomer can be suitably adopted to supply (dropping) mode etc.Polymerization temperature suitably can be selected according to the monomer used and the kind of solvent, the kind of polymerization starter etc., such as, can be set as about 20 DEG C ~ about 170 DEG C (typically being about 40 DEG C ~ about 140 DEG C).

The solvent used in solution polymerization suitably can be selected from known or usual organic solvent.Can use such as: be selected from a kind of solvent of the ketones such as ethers, methylethylketone, methyl ethyl diketone such as the lower alcohols such as the aliphatics such as the aromatics such as toluene, dimethylbenzene class (aromatic hydrocarbon based typically), ethyl acetate, hexane, hexanaphthene, methylcyclohexane or the haloalkane such as alicyclic hydro carbons, 1,2-ethylene dichloride hydro carbons, Virahol, n-butyl alcohol, sec-butyl alcohol, the trimethyl carbinol (such as the unary alcohol of carbonatoms 1 ~ 4), t-butyl methyl ether etc. or two or more mixed solvents.The organic solvent (can be mixed solvent) of boiling point under preferred use total pressure 1 normal atmosphere more than 20 DEG C and in the scope of less than 200 DEG C (being more preferably more than 25 DEG C and less than 150 DEG C).

The initiator used in polymerization suitably can be selected from known or usual polymerization starter according to the kind of polymerization process.Can preferably use such as: azo type polymerization initiator.As the concrete example of azo type polymerization initiator, can enumerate: 2, 2 '-Diisopropyl azodicarboxylate, 2, two (the 2-methyl-prop amidine) dithionate of 2 '-azo, 2, two (2-amidine propane) dihydrochloride of 2 '-azo, 2, two [2-(5-methyl-2-tetrahydroglyoxaline-2-base) propane] dihydrochloride of 2 '-azo, 2, two (the N of 2 '-azo, N '-dimethyleneisobutylamidine), 2, two [N-(2-the carboxy ethyl)-2-methyl-prop amidine] hydrate of 2 '-azo, 2, two (the 4-methoxyl group-2 of 2 '-azo, 4-methyl pentane nitrile), 2, 2 '-azo two (2, 4-methyl pentane nitrile), 2, 2 '-azo two (2-methylbutyronitrile), 1, 1 '-azo two (hexanaphthene-1-formonitrile HCN), 2, 2 '-azo two (2, 4, 4-trimethylpentane), 2, two (2 Methylpropionic acid) dimethyl esters of 2 '-azo etc.

As other example of polymerization starter, can enumerate: the persulphate such as Potassium Persulphate, ammonium persulphate; Benzoyl peroxide, tertbutyl peroxide, di-t-butyl peroxide, t-butyl per(oxy)benzoate, dicumyl peroxide, 1,1-bis(t-butylperoxy)-3,3, the peroxide type initiators such as 5-trimethyl-cyclohexane, 1,1-bis(t-butylperoxy) cyclododecane, hydrogen peroxide; The ethane that phenyl replaces etc. replace ethane initiator; Aromatic carbonyl; Deng.As the other example of polymerization starter, can enumerate: the redox type initiator that superoxide and reductive agent combine.As the example of described redox type initiator, can enumerate: the combination etc. of the combination (combination etc. of aqueous hydrogen peroxide solution and iron (II) salt) of the combination (combination etc. of aqueous hydrogen peroxide solution and xitix) of superoxide and xitix, superoxide and iron (II) salt, persulphate and sodium bisulfite.

Such polymerization starter can be used alone one or combinationally uses two or more.As long as the common usage quantity of the usage quantity of polymerization starter, such as, relative to whole monomer component 100 weight part, can more than about 0.005 weight part and below about 1 weight part (typically be more than about 0.01 weight part and below about 1 weight part) scope in select.

By described solution polymerization, the polymerization liquid that acrylic polymers is dissolved in the form of organic solvent can be obtained.As the acrylic polymers in technology disclosed herein, the reaction solution that can preferably use above-mentioned polymerization liquid or suitable aftertreatment be carried out to this reaction solution and obtains.Typically, the solution containing acrylic polymers after enforcement aftertreatment is adjusted to suitable viscosity (concentration) to use afterwards.Or, polymerization process (such as letex polymerization, photopolymerization, mass polymerization etc.) the synthesizing propylene acids polymers beyond solution polymerization process can be utilized, and use after this polymer dissolution is prepared into solution shape in organic solvent.

When the weight-average molecular weight (Mw) of the acrylic polymers in technology disclosed herein is too small, the cohesive force of tackiness agent is not enough, and on adherend surface, easily generation generation of adhesive deposit or curved surface tackiness easily decline sometimes.On the other hand, when Mw is excessive, sometimes the bounding force of adherend is easily declined.In order to balance bond properties and releasable with high level, preferred Mw is 10 × 10 ⁴above and 500 × 10 ⁴acrylic polymers in following scope.Be 20 × 10 by Mw ⁴above and 400 × 10 ⁴below (such as 30 × 10 ⁴above and 300 × 10 ⁴acrylic polymers below), can realize better result.At this, Mw refers to the value that the polystyrene standard obtained by GPC (gel permeation chromatography) is converted.

Binder composition in technology disclosed herein can for the composition containing tackifying resin.As tackifying resin, be not particularly limited, such as rosin based, terpenes, hydro carbons, epoxies, polyamide-based, the various tackifying resin such as elastomerics class, phenols, ketone can be used.Such tackifying resin can be used alone one or combinationally uses two or more.

As the concrete example of rosin based tackifying resin, can enumerate: the unmodified rosin (pine gum) such as gum resin, wood rosin, starex; These unmodified rosin are carried out modification by hydrogenation, disproportionation, polymerization etc. and the modified rosin (rosin etc. of staybelite, nilox resin, polymerized rosin, other chemically modified) obtained; Other various rosin derivative; Deng.As the example of above-mentioned rosin derivative, can enumerate: the rosin ester class such as the material (i.e. the carboxylate of rosin) unmodified rosin esterification obtained with alcohols, material (i.e. the carboxylate of modified rosin) of modified rosin (staybelite, nilox resin, polymerized rosin etc.) esterification being obtained with alcohols; By the unsaturated fatty acids modified rosin class that unmodified rosin or modified rosin (staybelite, nilox resin, polymerized rosin etc.) modification obtain by unsaturated fatty acids; By the unsaturated fatty acids modified rosin ester class that rosin esters modification obtains by unsaturated fatty acids; Carboxyl in unmodified rosin, modified rosin (staybelite, nilox resin, polymerized rosin etc.), unsaturated fatty acids modified rosin class or unsaturated fatty acids modified rosin ester class is carried out reduction treatment and the rosin alcohols obtained; The metal-salt of the rosin based (particularly rosin ester class) such as unmodified rosin, modified rosin, various rosin derivatives; By making rosin based (unmodified rosin, modified rosin, various rosin derivatives etc.) and phenol addition thermopolymerization and the rosin phenol resins that obtains in the presence of acid catalyst; Deng.

As the example of terpenes tackifying resin, can enumerate: the terpenoid resins such as α-pinene polymkeric substance, beta-pinene polymer, Dipentine (ジ ペ Application テ Application) polymkeric substance; By these terpenoid resin modifications (phenol modification, aromatic modified, hydrogenation modification, hydrocarbon modification etc.) and the modified terpene resinoid obtained; Deng.As the resinoid example of above-mentioned modified terpene, can enumerate: terpene phenolic resinoid, styrenated terpene resinoid, aromatic modified terpenoid resin, hydriding terpene resinoid etc.

As the example of hydrocarbon tackifying resin, can enumerate: the various hydrocarbon resins such as aliphatic hydrocarbon resin, aromatic hydrocarbon resin, aliphatic cyclic hydrocarbon resin, aliphatic/aromatic petroleum resin (styrene-olefin analog copolymer etc.), aliphatics/alicyclic petroleum resin, hydrogenated hydrocarbon resins, coumarone resinoid, coumarone-indenes resinoid.As aliphatic hydrocarbon resin, the polymkeric substance etc. being selected from the alkene of carbonatoms about 4 ~ about 5 and one or more aliphatic hydrocarbons of diene can be illustrated.As the example of above-mentioned alkene, can enumerate: 1-butylene, iso-butylene, 1-amylene etc.As the example of above-mentioned diene, can enumerate: divinyl, 1,3-pentadiene, isoprene etc.As the example of aromatic hydrocarbon resin, can enumerate: the polymkeric substance etc. containing vinylaromatic hydrocarbon (vinylbenzene, Vinyl toluene, alpha-methyl styrene, indenes, methyl indenes etc.) of carbonatoms about 8 ~ about 10.As the example of aliphatic cyclic hydrocarbon resin, can enumerate: the alicyclic hydrocarbon resin obtained carrying out being polymerized after so-called " C4 petroleum fractions " or " C5 petroleum fractions " Cyclodimerization; The polymkeric substance of cyclic diene compound (cyclopentadiene, dicyclopentadiene, ethylidene norbornene, Dipentine etc.) or its hydride; By the aromatic nucleus hydrogenation of aromatic hydrocarbon resin or aliphatic/aromatic petroleum resin and the alicyclic hydrocarbon resin obtained; Deng.

In technology disclosed herein, as above-mentioned tackifying resin, can preferably use softening temperature (softening temperature) such as, for the tackifying resin of more than about 100 DEG C (preferably more than about 120 DEG C, more preferably from about more than 135 DEG C, more than 140 DEG C).In addition, the terpene phenol resin of the softening temperature with more than above-mentioned lower value can preferably be used.By described tackifying resin, the double-sided adhesive sheet that resistance to rebound resilience is more excellent can be realized.The upper limit of the softening temperature of tackifying resin is not particularly limited, and can be such as less than about 200 DEG C (typically being less than about 180 DEG C).In addition, be defined through at the softening temperature of this said tackifying resin the value that the softening point test method (ring and ball method) that specifies in arbitrary standard of JIS K 5902 and JIS K 2207 measures.

The usage quantity of tackifying resin is not particularly limited, and suitably can set according to target bond properties (adhesive power etc.).Such as, take solids component as benchmark, preferably with relative to 100 parts by weight propylene acids polymers for the ratio of (more preferably from about more than 15 weight parts and below about 80 weight parts, further preferably more than about 20 weight parts and below about 60 weight parts) more than about 10 weight parts and below about 100 weight parts uses tackifying resin.

Linking agent can be used as required in above-mentioned binder composition.The kind of linking agent is not particularly limited, can from known or usual linking agent (such as, isocyanates linking agent, epoxies linking agent, azoles quinoline class linking agent, aziridines linking agent, melamine class linking agent, peroxide linking agent, ureas linking agent, metal alkoxide class linking agent, metallo-chelate class linking agent, metallic salt linking agent, carbodiimide class linking agent, amine cross-linking agent etc.) in suitable choice for use.Linking agent can be used alone one or combinationally uses two or more.The usage quantity of linking agent is not particularly limited, such as, relative to 100 parts by weight propylene acids polymers, can below about 10 weight parts (more than such as about 0.005 weight part and below about 10 weight parts, preferably more than about 0.01 weight part and below about 5 weight parts) scope in select.

Above-mentioned binder composition can contain various additives general in the field of the binder compositions such as flow agent, crosslinking coagent, softening agent, tenderizer, weighting agent, tinting material (pigment, dyestuff etc.), antistatic agent, antiaging agent, UV light absorber, antioxidant, photostabilizer as required.About so various additives, existing known additive can be used by ordinary method, not give feature of the present invention especially, therefore omit detailed description.

As release liner, release liner that can be known or usual in the field of suitable choice for use double-sided adhesive sheet.Such as, the release liner of the formation surface of liner substrate being implemented to lift-off processing can preferably be used.As the liner substrate (lift-off processing object) forming this release liner, can the suitably various resin film class of choice for use, stationery, dry goods, sheet rubber class, foaming body piece class, tinsel, their mixture (such as, having the sheet of the stepped construction of olefin resin at the two sides lamination of paper) etc.Above-mentioned lift-off processing can use known or usual stripping treatment agent (such as, polysiloxane-based, the stripping treatment agent such as fluorine-containing type, chain alkyl class) to be undertaken by ordinary method.In addition, the liner substrate of the low tackinesies such as olefine kind resin (such as polyethylene, polypropylene, ethylene-propylene copolymer, polyethylene/polypropylene mixture), fluoropolymer (such as tetrafluoroethylene, poly(vinylidene fluoride)) can be used as release liner and lift-off processing is not implemented to the surface of this liner substrate.Or, the release liner liner substrate of described low tackiness being implemented to lift-off processing can be used.

The coating of binder composition can use the such as known or usual coating machine such as gravure roll coating machine, reverse roll coating machine, touch roll coating machine, immersion roll-coater, metering bar coater, knife coater, spraying machine to carry out.Be not particularly limited, the glue spread of binder composition can be set as being formed (being namely benchmark with solids component) such as more than about 5 μm and the amount of the degree of the binder layer of the thickness (thickness of each one side) of less than about 150 μm after the drying.From the viewpoint of with the high level balance lightweight of double-sided adhesive sheet and/or slimming and bond properties, the thickness of the binder layer of above-mentioned each one side is set as more than about 10 μm and less than about 110 μm be suitable, be preferably set to more than about 15 μm and less than about 100 μm (be more preferably more than about 20 μm and less than about 75 μm, such as more than about 20 μm and less than about 50 μm, typically be more than about 20 μm and less than about 35 μm).From promotion crosslinking reaction, improve the consideration such as the viewpoint that manufactures efficiency, the drying of binder composition is preferably carried out under heating.Usually, the drying temperature of such as about 40 DEG C ~ about 120 DEG C can preferably be adopted.

As the method forming binder layer on foam base material, existing known various method can be applied.Can enumerate such as: above-mentioned binder composition is coated directly onto the method (direct method) on foam base material, above-mentioned binder composition is applied to suitable release surface forms binder layer in this release surface and this binder layer is fitted to the method (transfer printing) etc. of foam base material carrying out transfer printing.These Combination of Methods can be used.In addition, the first binder layer and the second binder layer can adopt diverse ways.When using the binder composition containing solvent, manufacture the viewpoints such as efficiency consider from promotion crosslinking reaction, raising, preferably make this binder composition dry under heating.

The aggregate thickness (aggregate value of the thickness of the first binder layer and the thickness of the second binder layer) of binder layer is not particularly limited, such as, can be set as more than 10 μm and less than 300 μm.From the viewpoint of bond properties, usually the aggregate thickness of binder layer is set as that more than 20 μm is suitable, is preferably more than 30 μm, is more preferably more than 40 μm.In addition, from the viewpoint of the thickness of foam base material easily guaranteeing to play desired characteristic, usually the aggregate thickness of binder layer is set as that less than 250 μm is suitable, be preferably less than 200 μm, be more preferably less than 150 μm, more preferably less than 100 μm, such as, be less than 70 μm.

The thickness of the first binder layer and the thickness of the second binder layer can be identical thickness, also can be different thickness.Usually, the thickness of two binder layers can be preferably adopted to be the formation of roughly the same degree.In addition, each binder layer can have any one form of individual layer and multilayer.

In the scope of not obvious infringement effect of the present invention, double-sided adhesive sheet disclosed herein can also containing layer (middle layer, the undercoat etc. beyond foam base material and binder layer.Hereinafter also referred to " other layer ").Such as, other layer above-mentioned can be set between foam base material and any one or two binder layers.For the double-sided adhesive sheet of such formation, the thickness of other layer above-mentioned is included in the total thickness of double-sided adhesive sheet (that is, from an adhesive face to the thickness of another adhesive face).

According to an optimal way of technology disclosed herein, display pressing adhesive power can be provided to be 45N/cm ²(be more preferably 60N/cm above ²above, 75N/cm typically is ²above, such as 80N/cm ²the double-sided adhesive sheet of performance above).Even if press the so high double-sided adhesive sheet of adhesive power when this double-sided adhesive sheet of such as narrowed width and adherend being fitted, be also not easy to produce the stripping caused by internal stress, gluing reliability is excellent, therefore preferably.

Above-mentioned pressing adhesive power is defined as follows: window frame shape (also referred to as " the frame-shaped ") double-sided adhesive sheet utilizing horizontal 59mm, longitudinal 113mm, width 1mm, stainless steel plate (SUS plate) is fitted under the condition that crimps of roller round trip making 5kg with sheet glass, make sample for evaluation thus, for this sample for evaluation, above-mentioned sheet glass is pressed from interior along the thickness direction of sheet glass, by until sheet glass to be separated the maximum stress that period observes with SUS plate be defined as pressing adhesive power with the load speed of 10mm/ minute.More specifically, above-mentioned pressing adhesive power can by the step measurements recorded in embodiment described later.

According to another optimal way of technology disclosed herein, be presented in the shock-resistance evaluation that the method by recording in embodiment described later that can be implemented in is carried out room temperature (23 DEG C) fall 18 times, after low temperature (-5 DEG C) falls 60 times, then do not observe the double-sided adhesive sheet of the shock-resistance of the level of stripping yet.

According to another optimal way of technology disclosed herein, the method that can be provided in by recording in embodiment described later carry out to showing the double-sided adhesive sheet of stripping strength (stripping strength) for the performance of more than 15N/20mm (being more preferably more than 16N/20mm, more preferably more than 17N/20mm) in 180 ° of stripping tests of stainless steel (SUS304BA).The double-sided adhesive sheet display so high to the stripping strength of SUS304BA and the good glueability of adherend, therefore preferably.

Double-sided adhesive sheet disclosed herein can have desired optical characteristics (transmissivity, reflectivity etc.).Such as, for the double-sided adhesive sheet of shading purposes, preferred transmission of visible light is more than 0% and less than 15% (be more preferably more than 0% and less than 10%).In addition, for the double-sided adhesive sheet of luminous reflectance purposes, preferred visible reflectance is more than 20% and less than 100% (be more preferably more than 25% and less than 100%).Foam substrate coloring etc. can be regulated by such as described above by the optical characteristics of double-sided adhesive sheet.

Double-sided adhesive sheet disclosed herein, from preventing the viewpoints such as metallic corrosion from considering, preferably not halogen-containing.The not halogen-containing this point of double-sided adhesive sheet, such as may be used for electrically at this double-sided adhesive sheet, electronic unit fixing time, favourable characteristic can be become.In addition, can suppress to produce halogen-containing gas during burning, be also therefore preferred from the viewpoint of alleviating carrying capacity of environment.Not halogen-containing double-sided adhesive sheet can be obtained by the following means of independent or appropriately combined use: do not use halogen compounds as the raw material of foam base material, tackiness agent wittingly, use the foam base material not coordinating halogen compounds wittingly, use during additive and do not use the additive etc. deriving from halogen compounds.

Double-sided adhesive sheet disclosed herein, be not particularly limited, may be used for comprising the adherend of the elastomeric materials such as resin material, natural rubber, isoprene-isobutylene rubber and their matrix materials etc. such as the inorganic materials such as the such as metallic substance such as SUS, aluminium, glass, pottery, polycarbonate (PC), polymethylmethacrylate (PMMA), polypropylene, polyethylene terephthalate (PET).

Double-sided adhesive sheet disclosed herein shows excellent pressing adhesive power, can become the double-sided adhesive sheet that gluing reliability is high.In addition, double-sided adhesive sheet disclosed herein contains foam base material, therefore can become water-repellancy, concavo-convex tracing ability, stopping property, double-sided adhesive sheet that resistance to rebound resilience is excellent.Therefore; utilize such feature; electronics applications can be preferably applied to, such as: the purposes such as the fixing use of protection panel (lens) of the display part of protection portable electric appts (such as mobile phone, smart mobile phone, panel computer, notebook computer etc.), use fixed by key-press module component, the decoration panel of televisor fixes use, the series of cells of PC fixes use, the lens waterproof use of Digital Video of mobile phone.As particularly preferred purposes, portable electric appts can be preferred for.Such as, the purposes etc. will the protection panel (lens) of display part being protected to engage with housing in such portable electric appts is adapted at.

In addition, " lens " in this specification sheets are the concepts comprising the hyalosome of display light refraction action and the hyalosome both sides of unglazed refraction action.That is, " lens " in this specification sheets also comprise without refraction action, the protection panel of the just display part of protection portable electric appts.

Below, some embodiments related to the present invention are described, but, be not intended to limit the invention to the content shown in described embodiment.In addition, in the following description, " part " and " % " is weight basis if not otherwise specified.

In the following description, weight-average molecular weight (Mw) measures as follows.

By binder composition 130 DEG C of dryings 2 hours, then flood 12 hours in tetrahydrofuran (THF) (THF) and make the stripping of THF soluble ingredient, thus preparation contains the THF solution of this THF soluble ingredient with the concentration of 0.1g/L.The filtrate obtained for this THF solution of membrane filter by mean pore size 0.45 μm carries out GPC, obtains the weight-average molecular weight (polystyrene standard conversion) of THF soluble ingredient.As GPC device, use the model " HLC-8320GPC " (post: TSKgel GMH-H (S)) that TOSOH Co., Ltd manufactures.

The sample of double-sided adhesive sheet (example 1 ~ example 4) is following respectively to be made.

(example 1)

[making of acrylic polymers]

In the reaction vessel possessing agitator, thermometer, nitrogen ingress pipe, reflux exchanger and dropping funnel, make 100 parts of n-butyl acrylates, 5 parts of vinylformic acid, 0.2 part of benzoyl peroxide as polymerization starter is dissolved in toluene as solvent.Then, while slowly stirring, import nitrogen, the liquid temperature in reaction vessel remained on about 60 DEG C and carries out about 6 hours polyreactions, thus obtaining acrylic polymers.The weight-average molecular weight Mw of the acrylic polymers in the solution obtained is 55 × 10 ⁴.

[making of binder composition]

Then, relative to aforesaid propylene acids polymers solution (nonvolatile component) 100 parts, (Arakawa Chemical Industries, Ltd. manufactures to add 30 parts of terpene phenol resin, goods name " タ マ ノ Le 803L ") and 10 parts of terpene phenol resin (An Yuan Chemical Co., Ltd manufactures, goods name " YS Port リ ス タ ー S145 ") as tackifying resin, and (Nippon Polyurethane Industry Co., Ltd. manufactures to add 1 part of isocyanates linking agent, goods name " コ ロ ネ ー ト L ") and 0.03 part of epoxies linking agent (Mitsubishi Gas Chemical Co., Ltd's manufacture, trade(brand)name " テ ト ラ ッ De C ") as linking agent, thus made acrylic pressure-sensitive adhesive compositions.

The polyvinyl resin system of preparation foaming body piece (hereinafter referred to as " base material A ") is as foam base material.The thickness of above-mentioned base material A is 150 μm, 25% compressive strength is 108kPa, longitudinal tensile strength (tensile strength (MD)) is 3.18MPa, and the tensile strength (tensile strength (CD)) of width is 5.50MPa.Measured by above-mentioned measuring method and to calculate in above-mentioned base material A the longitudinal direction (MD) of contained bubble, width (CD), thickness direction (VD) each mean air bubble diameter and as the aspect ratio (CD/VD) of their ratio and the result of aspect ratio (MD/CD) be, the aspect ratio (CD/VD) of above-mentioned base material A is 2.3, and aspect ratio (MD/CD) is 2.6.The photo during cross section utilizing scanning electron microscope (SEM) to observe when being cut off by above-mentioned base material A along the plane parallel with CD with VD (i.e. the direction of vertical line and the consistent plane of MD) has been shown in Fig. 2.

At commercially available release liner, (Zhu Hua converted paper Co., Ltd. manufactures, goods name " SLB-80W3D ") a face on be coated with above-mentioned binder composition and make dried thickness be 25 μm, and 100 DEG C of dryings 2 minutes, thus form binder layer.Then, above-mentioned binder layer is fitted on a surface of above-mentioned base material A, obtains one side adhesive sheet thus.

Then, above-mentioned binder composition is applied on a face of release liner same as described above, makes dried thickness be 25 μm, and 100 DEG C of dryings 2 minutes, thus form binder layer.This binder layer is fitted to the foam base material of above-mentioned one side adhesive sheet another on the surface.Then, make obtained structure by the laminating machine (0.3MPa, speed 0.5m/ minute) of 80 DEG C once, then maintenance one day in the baking oven of 50 DEG C.Thus, the double-sided adhesive sheet (example 1) that total thickness is 200 μm is obtained.

(example 2)

Except using base material B to replace except above-mentioned base material A, obtain the double-sided adhesive sheet (example 2) that total thickness is 150 μm in the same manner as the making of the double-sided adhesive sheet of above-mentioned example 1.

At this, the thickness of base material B is 100 μm, 25% compressive strength is 149kPa, and longitudinal tensile strength (tensile strength (MD)) is 4.62MPa, and the tensile strength (tensile strength (CD)) of width is 7.51MPa.The aspect ratio (CD/VD) of above-mentioned base material B is 1.9, and aspect ratio (MD/CD) is 2.8.

(example 3)

Except using base material C to replace except above-mentioned base material A, obtain the double-sided adhesive sheet (example 3) that total thickness is 200 μm in the same manner as the making of the double-sided adhesive sheet of above-mentioned example 1.

At this, the thickness of base material C is 150 μm, 25% compressive strength is 150kPa, and longitudinal tensile strength (tensile strength (MD)) is 9.50MPa, and the tensile strength (tensile strength (CD)) of width is 8.20MPa.The aspect ratio (CD/VD) of above-mentioned base material C is 9.0, and aspect ratio (MD/CD) is 0.7.The photo during cross section utilizing scanning electron microscope (SEM) to observe when being cut off by above-mentioned base material C along the plane parallel with CD with VD (i.e. the direction of vertical line and the consistent plane of MD) has been shown in Fig. 3.

(example 4)

Except using base material D to replace except above-mentioned base material A, obtain the double-sided adhesive sheet (example 4) that total thickness is 150 μm in the same manner as the making of the double-sided adhesive sheet of above-mentioned example 1.

At this, the thickness of base material D is 100 μm, 25% compressive strength is 75kPa, and longitudinal tensile strength (tensile strength (MD)) is 1.99MPa, and the tensile strength (tensile strength (CD)) of width is 2.97MPa.The aspect ratio (CD/VD) of above-mentioned base material D is 4.3, and aspect ratio (MD/CD) is 0.9.

By being used for the thickness of the base material of the double-sided adhesive sheet making above-mentioned example 1 ~ example 4, kind, apparent density, degree of crosslinking, mean air bubble diameter aspect ratio (CD/VD and MD/CD), 25% compressive strength, tensile strength (MD and CD), 90 DEG C of heated dimensions velocity of variation (MD and CD) are summarized in table 1.In addition, above-mentioned base material two sides formed the thickness of binder layer and the total thickness of above-mentioned double-sided adhesive sheet be also summarized in table 1.

Table 1

< evaluation test >

(1) adhesive power is pressed

Double-sided adhesive sheet is cut into the window frame shape (frame-shaped) of the horizontal 59mm shown in Fig. 4, longitudinal 113mm, wide 1mm, thus obtains window frame shape double-sided adhesive sheet.Use this window frame shape double-sided adhesive sheet, once come and go by making the roller of 5kg and carry out crimping and the sheet glass of horizontal 59mm, longitudinal 113mm, thick 1mm (is used the Gorilla glass that Corning Incorporated manufactures.The stainless steel plate (SUS plate) (horizontal 70mm, longitudinal 130mm, thick 2mm) having the through hole of diameter 15mm with central part down together) is fitted, thus obtains sample for evaluation.

Fig. 4 is the sketch chart of above-mentioned sample for evaluation, and (a) is vertical view, and (b) is A-A ' sectional view.In Fig. 4, symbol 21 represents SUS plate, and symbol 2 represents window frame shape double-sided adhesive sheet, and symbol 22 represents sheet glass, and symbol 21A represents the through hole that SUS plate 21 is arranged.

These sample for evaluations are set on universal tensile compression testing machine (device name " Compression and Expansion trier TG-1kNB ", ミ ネ ベ ア Co., Ltd. manufactures).Then, make pole by the through hole of SUS plate, with the speed of 10mm/ minute, this pole declined, thus along from the direction that SUS plate leaves by laminated glass.Then, measure until the maximum stress that observes during being separated with SUS plate of sheet glass is as pressing adhesive power.In addition, be determined at 23 DEG C, carry out under the environment of 50%RH.

Fig. 5 is the general profile chart of the measuring method representing pressing adhesive power, and symbol 21 represents SUS plate, and symbol 2 represents window frame shape double-sided adhesive sheet, and symbol 22 represents sheet glass, and symbol 23 represents pole, and symbol 24 represents brace table.Sample for evaluation is fixed on the brace table 24 of Compression and Expansion trier as shown in Figure 5, and the sheet glass 22 of sample for evaluation is pressed by the pole 23 of the through hole 21A by SUS plate 21.In addition, during above-mentioned pressing adhesive power measures, SUS plate 21 bends the load applied because sheet glass 22 is pressed by pole 23 or breakage.

(2) peeling strength test (to SUS304BA)

On an adhesive face of double-sided adhesive sheet, polyethylene terephthalate (PET) film of coating thickness 25 μm, is cut into the size of wide 20mm, long 100mm, thus has made working sample.

23 DEG C, under the environment of 50%RH, another adhesive face of said determination sample being exposed, by making the roller of 2kg once come and go, this another adhesive face being crimped onto the surface of stainless steel plate (SUS304BA plate).After it is placed 30 minutes under equivalent environment, use above-mentioned universal tensile compression testing machine, according to JIS Z 0237, draw speed 300mm/ minute, peel off under the condition of peel angle 180 °, and the mean load measured now, obtain stripping strength thus (also referred to as " stripping strength ".Unit: N/20mm width).

(3) shock-resistance (normal temperature and low temperature)

Double-sided adhesive sheet is cut into the window frame shape (frame-shaped) of the horizontal 59mm shown in Fig. 6, longitudinal 113mm, wide 1mm, thus obtains window frame shape double-sided adhesive sheet.Use this window frame shape double-sided adhesive sheet, once come and go by making the roller of 5kg and carry out crimping and by a PC plate (polycarbonate plate, horizontal 70mm, longitudinal 130mm, thick 2mm) fit with the 2nd PC plate (horizontal 59mm, longitudinal 113mm, thick 0.55mm), thus obtain sample for evaluation (with reference to figure 6 (a) (b)).

Fig. 6 is the sketch chart of above-mentioned sample for evaluation, and (a) is vertical view, and (b) is its B-B ' sectional view.In Fig. 6, symbol 31 represents a PC plate, and symbol 3 represents window frame shape double-sided adhesive sheet, and symbol 32 represents the 2nd PC plate.

The upper weight installing 160g at the back side (face of the opposition side in the face of fitting with the 2nd PC plate) of a PC plate of these sample for evaluations.For the above-mentioned sample for evaluation with weight, carry out making it freely fall the shatter test of 18 times to concrete slab from the height of 1.2m under room temperature (about 23 DEG C).Now, the direction fallen is regulated to make 6 of above-mentioned sample for evaluation faces downward successively.That is, by the mode that falls once, 3 times are repeated respectively for 6 faces.

Then, fall each time all by whether being peeling between visual confirmation the one PC plate and the 2nd PC plate, and by until the drop number be peeling is evaluated as the shock-resistance under room temperature (23 DEG C).When also not observing stripping after falling for 18 times, be expressed as " more than 18 times " or " >18 ".

Do not observe the sample of stripping after falling 18 times during shock-resistance under above-mentioned room temperature is tested, then carry out the shock-resistance test under low temperature (-5 DEG C) yet.Namely, carry out from the height of 1.2m to the free-falling shatter test of concrete slab under the environment of-5 DEG C to the sample for evaluation after the test of the shock-resistance test under room temperature, fall each time all by whether being peeling between visual confirmation the one PC plate and the 2nd PC plate, and by until the drop number be peeling is evaluated as the shock-resistance under low temperature (-5 DEG C).Now, 6 face modes fallen respectively once for above-mentioned sample for evaluation repeat 10 times, when also not observing stripping after 60 times fall, are expressed as " more than 60 times " or " >60 ".

The above-mentioned evaluation result of the double-sided adhesive sheet of example 1 ~ example 4, as shown in Table 1 above.

As shown in Table 1 above, the aspect ratio (CD/VD) obviously with foam base material is less than 3, aspect ratio (MD/CD) is greater than the foam base material of 1 double-sided adhesive sheet example 1 and example 2, compare with example 4 with double-sided adhesive sheet example 3, show higher pressing adhesive power.In addition, the double-sided adhesive sheet of example 1 and example 2 shows excellent stripping strength.In addition, the double-sided adhesive sheet of example 1 and example 2 shows high-impact under room temperature (23 DEG C) and low temperature (-5 DEG C).

Above, understand concrete example of the present invention in detail, but these examples are only illustrate, and do not limit claims.The technology recorded in claims comprises carries out various distortion, change and the technology obtained to above-mentioned illustrative concrete example.

Claims (9)

1. a double-sided adhesive sheet, its second binder layer of second containing foam base material, be arranged on the first binder layer of the first surface of described foam base material and be arranged on described foam base material;

The thickness of described foam base material is less than 1000 μm;

Described foam base material, the aspect ratio (CD/VD) that represents relative to the ratio of the mean air bubble diameter of the thickness direction (VD) of described foam base material with the mean air bubble diameter of the width (CD) of described foam base material is for less than 3;

Described foam base material, the aspect ratio (MD/CD) that represents relative to the ratio of the mean air bubble diameter of the width (CD) of described foam base material with the mean air bubble diameter of the longitudinal direction (MD) of described foam base material is greater than 1.

2. double-sided adhesive sheet as claimed in claim 1, wherein,

The thickness of described double-sided adhesive sheet is more than 100 μm and less than 500 μm.

3. double-sided adhesive sheet as claimed in claim 1 or 2, wherein,

Described foam base material is polyolefins foam base material.

4. the double-sided adhesive sheet according to any one of claims 1 to 3, wherein,

25% compressive strength of described foam base material is more than 50kPa.

5. the double-sided adhesive sheet according to any one of Claims 1 to 4, wherein,

The longitudinal tensile strength of described foam base material is more than 1MPa and below 30MPa.

6. the double-sided adhesive sheet according to any one of Claims 1 to 5, wherein,

The density of described foam base material is 0.2g/cm ³above and 0.6g/cm ³below.

7. the double-sided adhesive sheet according to any one of claim 1 ~ 6, wherein,

Described foam base material, heated dimensions velocity of variation longitudinal at 90 DEG C is more than-10% and less than 10%, and at 90 DEG C, the heated dimensions velocity of variation of width is more than-10% and less than 10%.

8. the double-sided adhesive sheet according to any one of claim 1 ~ 7, wherein,

In described first binder layer and described second binder layer at least any one contains acrylic adhesives.

9. the double-sided adhesive sheet according to any one of claim 1 ~ 8, it is for engaging the parts of portable electric appts.