JP5009887B2 - Manufacturing method of adhesive sheet - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition constituting a pressure-sensitive adhesive sheet, and particularly relates to a pressure-sensitive adhesive composition that is cured by irradiation with an active energy ray such as ultraviolet rays and develops pressure-sensitive adhesive properties.

Conventionally, as the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive sheet, an ultraviolet curable pressure-sensitive adhesive composition that is cured by ultraviolet irradiation has been used.
As an example of an ultraviolet curable pressure-sensitive adhesive composition, JP-A-9-40928 discloses a pressure-sensitive adhesive composition having an acrylic polymer as a base material. The pressure-sensitive adhesive composition is cured by further polymerization of the acrylic polymer by ultraviolet rays, so that not only does the organic solvent need not be used, but also the thermal stability of the pressure-sensitive adhesive sheet obtained by curing the pressure-sensitive adhesive composition High cohesion.

  However, the pressure-sensitive adhesive sheet as described above has low strength and insufficient adhesion. In addition, since the adhesive sheet is not flexible enough, when the adherend surface of the adherend of the adhesive sheet is a curved surface, the adhesive sheet cannot follow the curved surface, and the end of the adhesive sheet floats from the adherend surface. .

In the above-mentioned pressure-sensitive adhesive composition, at least two kinds of acrylic monomers and a vinyl monomer are previously polymerized to form an acrylic polymer, and then a photopolymerization initiator is added to the acrylic polymer to form a pressure-sensitive adhesive composition. Therefore, the production process of the pressure-sensitive adhesive composition is complicated. Moreover, since this adhesive composition has an acrylic polymer as a main component, its viscosity is high, and when applying an adhesive composition, it is necessary to heat-melt (hot melt method). The equipment required for the hot melt method is simple, but it is difficult to handle because the viscosity of the pressure-sensitive adhesive composition is high.
JP-T-2001-503811 JP 58-196277 A JP-A-63-046881 JP 2000-109770 A JP-A-4-161474 JP-A-4-87635 JP-A-3-250081 JP-A-1-272676

  The present invention was created in order to solve the disadvantages of the prior art described above, and its purpose is to provide an ultraviolet curable adhesive having excellent strength and adhesiveness after curing and high flexibility after curing. It is to provide an agent composition.

  As a result of intensive studies by the present inventors, by adding a specific type of acrylic monomer at a specific blending ratio to the resin component that becomes the base material of the pressure-sensitive adhesive composition, only the strength and adhesiveness of the pressure-sensitive adhesive sheet are obtained. Instead, the present inventors have found that the flexibility of the adhesive sheet is increased.

The invention according to claim 1 made based on such knowledge is a method for producing a pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive sheet having at least two pressure-sensitive adhesive layers and having a substrate disposed between the pressure-sensitive adhesive layers. Applying a pressure-sensitive adhesive composition to at least one surface of the support, forming a first coating layer, placing the substrate on the first coating layer, and on the substrate Either or both of the step of applying the pressure-sensitive adhesive composition to form the second coating layer, the surface on the side where the support is disposed, and the surface on the side where the second coating layer is disposed The first and second adhesive layers are formed by irradiating the first and second coating layers, and the first and second adhesive layers are heated. , the pressure-sensitive adhesive composition, a base material containing acrylate, photopolymerization to polymerize the base material by irradiation with ultraviolet light An initiator, a crosslinking agent to form a crosslinked structure, is contained, and a tackifier for imparting tackiness, the acrylate in which the base material contains a first acrylate consisting of (a) t-Butyl acrylate If, (b) a second acrylate consisting of phenoxyethyl acrylate, is contained an acrylic polymer obtained by polymerizing the (c) acrylate or 2-ethylhexyl acrylate and butyl acrylate and acrylic acid, the first acrylate and the addition amount below 20 wt% 2.5 wt% or more of the total matrix, and the addition amount of the second acrylate to 20 wt% 2.5 wt% or more of the total matrix, before Symbol crosslinking agent Is a method for producing a pressure-sensitive adhesive sheet containing an isocyanate compound as a crosslinking main agent.
Invention of Claim 2 is a manufacturing method of the adhesive sheet which has an adhesive layer of at least 2 layers, and manufactures the adhesive sheet by which the base material was arrange | positioned between the said adhesive layers, Comprising: At least one of a support body Applying a pressure-sensitive adhesive composition to a surface to form a first coating layer; applying a pressure-sensitive adhesive composition to one surface of the substrate to form a second coating layer; and the support. A step of bringing the first coating layer surface on the body into contact with a surface of the base material on which the second coating layer is not formed, a surface on the side where the support is disposed, and the first Irradiating either one or both of the surfaces on which the two coating layers are disposed with ultraviolet rays, curing the first and second coating layers to form the first and second adhesive layers; the first, and a step of heating the second adhesive layer, the pressure-sensitive adhesive composition, the base material containing acrylate , A photopolymerization initiator for polymerizing the base material by the ultraviolet irradiation, and a crosslinking agent to form a crosslinked structure, is contained, and a tackifier for imparting tackiness, the acrylates the base material contains the ( a first acrylate consisting of a) t-butyl acrylate, (b) a second acrylate consisting of phenoxyethyl acrylate, obtained by polymerization (c) acrylate or 2-ethylhexyl acrylate and butyl acrylate and acrylic acid acrylic It is contained a polymer, the first the amount of acrylate to 20 wt% 2.5 wt% or more of the total matrix, 2.5 wt of the total matrix of the added amount of the second acrylate and% or more 20 wt% or less, before Symbol crosslinking agent, a method of manufacturing the pressure-sensitive adhesive sheet to an isocyanate compound as a crosslinking base resin.
請 Motomeko 3 the described invention, the pressure-sensitive adhesive sheet to a method of producing a pressure-sensitive adhesive sheet according any one of claims 1 or claim 2, in the crosslinking agent, the addition of hydroxypropyl acrylate as a crosslinking agent It is a manufacturing method.
Invention of Claim 4 is a manufacturing method of the adhesive sheet of any one of Claim 1 thru | or 3, Comprising: 2-ethylhexyl acrylate, butyl acrylate, n-propyl acrylate, nonyl acrylate, isooctyl acrylate Or it is the manufacturing method of the adhesive sheet which makes those acrylate contain those mixtures.
Invention of Claim 5 is a manufacturing method of the adhesive sheet of any one of Claim 1 thru | or 4, Comprising: As said tackifier, rosin, terpene phenol, or an acrylic tackifier is used. It is a manufacturing method of the pressure sensitive adhesive sheet to contain.
Invention of Claim 6 is a manufacturing method of the adhesive sheet of any one of Claim 1 thru | or 5, Comprising: Manufacture of the adhesive sheet which heats said 1st, 2nd adhesive layer for 24 hours or more Is the method.

The acrylic monomer contained in the third resin component refers to acrylate (acrylic ester) or methacrylate. An acrylic polymer refers to a polymer of acrylic monomers.
Further, t-butyl acrylate as the first resin component is shown in the following chemical formula (1), and phenoxyethyl acrylate as the second resin component is shown in the following chemical formula (2).

  The present invention is configured as described above, and when the adhesive composition of the present invention is irradiated with ultraviolet rays, the first and second resin components t-butyl acrylate and phenoxyethyl acrylate are the third resin component. Embedded in the polymerization of When acrylates such as t-butyl acrylate and phenoxyethyl acrylate are incorporated into the polymerization, the resulting polymer is more flexible than when methacrylate is incorporated into the polymerization. Therefore, the pressure-sensitive adhesive layer made of the cured pressure-sensitive adhesive composition has appropriate flexibility, and when the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer is bonded to the curved surface, the end portion does not rise from the curved surface.

In addition, since acrylic acid and hydroxypropyl acrylate react with isocyanate, which is a crosslinking agent, and function as a crosslinking point of the crosslinked structure, a more developed network structure is obtained by using a crosslinking agent containing both a crosslinking agent and a crosslinking aid. Is formed.
Moreover, since tackifiers, such as rosin and terpene phenol, are added to the adhesive composition of this invention, the adhesiveness of an adhesive sheet is also high.

As the third resin component that is the main component of the base material, an acrylic monomer or a mixture of an acrylic monomer and an acrylic polymer can be used. When the third resin component is composed only of an acrylic polymer, the viscosity of the entire pressure-sensitive adhesive composition becomes high, and the coating process of the pressure-sensitive adhesive composition becomes difficult, which is not preferable.
In addition, according to the present invention, it is not necessary to polymerize the resin component that constitutes the base material in advance, so that the process of creating the pressure-sensitive adhesive composition is simple.

  According to the present invention, both t-butyl acrylate and phenoxyethyl acrylate are added to the base material in appropriate amounts, so that the adhesive layer strength after curing is not reduced, and the strength of the adhesive layer is reduced. In addition, since the flexibility is increased, the pressure-sensitive adhesive sheet of the present invention can be used for bonding the curved surface of the adherend.

First, the pressure-sensitive adhesive composition of the present invention is prepared as follows.
For a base material comprising a first resin component that is t-butyl acrylate, a second resin component that is phenoxyethyl acrylate, and a third resin component that is an acrylic monomer or a mixture of an acrylic monomer and an acrylic polymer. Then, a crosslinking agent, a tackifier, and a photopolymerization initiator are added and mixed at a predetermined blending ratio, and a pressure-sensitive adhesive composition is prepared under the condition that ultraviolet rays are not irradiated.

  Here, the content of the first resin component and the content of the second resin component were 2.5 wt% or more and 20 wt% or less of the whole base material, respectively. In addition, the first to third resin components are each pasty at normal temperature, and the polymerization reaction of the first to third resin components does not occur under the conditions where ultraviolet rays are not irradiated, so the pressure-sensitive adhesive composition is pasty. .

  Next, the adhesive sheet of this invention is produced as follows using the said adhesive composition. Reference numeral 10 in FIG. 1 shows an example of a manufacturing apparatus used for manufacturing an adhesive sheet. The manufacturing apparatus 10 includes first and second coating apparatuses 14 and 21, a bonding apparatus 17, and an ultraviolet irradiation apparatus 23. have.

  In order to produce an adhesive sheet using this manufacturing apparatus 10, first, a first roll 12 in which a peeling tape 51 as a support is wound around a winding core is mounted on the unwinding shaft 11 of the manufacturing apparatus 10. . Here, a release paper having a film thickness of 150 μm was used as the release tape 51.

Next, when the end portion of the release tape 51 is fed from the first roll 12 to the first coating device 14 and the adhesive composition is applied to the surface of the release tape 51 by the first application device 14, the release tape 51 adheres to the surface of the release tape 51. A coating layer (first coating layer) of the agent composition is formed. Reference numeral 61 in FIG. 2A shows the tape on which the first coating layer is formed, and reference numeral 51 in FIG. 2 shows the first coating layer.
A second roll 16 in which a tape-shaped nonwoven fabric 55 as a base material is wound around a winding core is attached to the second unwinding shaft 15 of the manufacturing apparatus 10. 55 ends are fed out, and the non-woven fabric 55 and the tape 61 in a state where the first coating layer 52 is formed are respectively sent to the bonding device 17.

  The laminating device 17 has crimping rolls 18 and 19, and the tape 61 and the nonwoven fabric 55 are crimped in a state where the surface on which the first coating layer 52 is disposed and the nonwoven fabric 55 face each other. 18 and 19, the non-woven fabric 55 is pressed against the surface of the first application layer 52 of the tape 61 supported by the one press-bonding roll 18 by the other press-bonding roll 19, and the non-woven fabric 55 becomes the first application layer 52. Affixed to the surface. Reference numeral 62 in FIG. 2B shows the tape in this state.

When the tape 62 with the non-woven fabric 55 attached is fed to the second coating device 23 and the adhesive composition is applied to the surface of the non-woven fabric 55 of the tape 62 by the second coating device 21, The coating layer is formed. Reference numeral 64 in FIG. 2C shows the tape in that state, and reference numeral 54 in FIG. 2C shows the second coating layer.
Next, the tape 64 on which the second coating layer 54 is formed is sent to the ultraviolet irradiation device 23 to irradiate the surface of the second coating layer 54 of the tape 64 with ultraviolet rays. Since at least the second coating layer 54 and the nonwoven fabric 55 transmit ultraviolet rays, the ultraviolet rays are also applied to the first coating layer 52.

  When the first and second coating layers 52 and 54 are irradiated with ultraviolet rays, the polymerization reaction of the base material is started by the photopolymerization initiator contained in the pressure-sensitive adhesive composition. At this time, the crosslinking assistant serves as a crosslinking point of the crosslinking main agent, a network structure is formed in the polymer of the base material, and the tackiness agent develops tackiness in the entire coating layer.

Reference numeral 65 in FIG. 2D indicates a tape in which the first and second coating layers 52 and 54 are cured by polymerization of the base material. Reference numerals 53 and 57 in the figure denote first and second adhesive layers formed by curing the first and second coating layers 52 and 54, respectively. 57 and the nonwoven fabric 55 disposed between the adhesive layers 53 and 57 constitute the adhesive sheet 50 of the present invention.
When the tape 65 in this state is wound by the winding shaft 25 of the manufacturing apparatus 10, a third roll 27 is formed around the winding shaft 25.

  When the tape 65 is unwound from the third roll 27 and cut into a desired shape and then the release tape 51 is turned, the release tape 51 is peeled from the adhesive sheet 50. Since the first and second adhesive layers 53 and 57 having adhesiveness are disposed on both surfaces of the nonwoven fabric 55 of the adhesive sheet 50, the adhesive tape 51 functions as a double-sided adhesive tape.

Although the above demonstrated the case where an adhesive composition was apply | coated to the nonwoven fabric 55 stuck to the 1st application layer 52, this invention is not limited to this.
Reference numeral 30 in FIG. 3 shows another example of the manufacturing apparatus. The non-woven fabric 75 is fed from the second roll 36 attached to the second unwinding shaft 35 to the second coating apparatus 41, and the second coating is performed. A second coating layer is formed on the surface of the nonwoven fabric 75 by the device 41. Reference numeral 82 in FIG. 4A indicates a tape in which the second coating layer 74 is formed on the surface of the nonwoven fabric 75.

  Separately, the peeling tape 71 is fed out from the first roll 32 mounted on the first unwinding shaft 31, and the tape 81 having the same structure as that shown in FIG. Is made. The tape 81 in that state and the tape 82 in which the second coating layer 74 is formed are respectively sent to the laminating device 37, and the tape 81 in a state where the first coating layer 72 and the nonwoven fabric 75 are opposed to each other. , 82 is passed between the press rolls 38, 39, the non-woven fabric 75 is pressed against the first coating layer 72 by the press rolls 38, 39, and the tapes 81, 82 are bonded to each other.

Reference numeral 84 in FIG. 4B shows a single tape in which two tapes 81 and 82 are bonded together. When the tape 84 is fed through the ultraviolet irradiation device 43 and irradiated with ultraviolet rays, the first and second tapes are shown. The two coating layers 72 and 74 are cured to form first and second adhesive layers.
Reference numeral 85 in FIG. 4C shows the tape in that state, and the first and second adhesive layers 73 and 77 and the nonwoven fabric 75 constitute the adhesive sheet 70 of the present invention. If the tape 85 in a state where the adhesive sheet 70 is formed is wound around the winding shaft 45, the third roll 47 is formed around the winding shaft 45.

  Although the above demonstrated the adhesive sheet which consists of a base material and two adhesive layers, this invention is not limited to this. For example, the present invention includes a pressure-sensitive adhesive sheet in which three or more pressure-sensitive adhesive layers are laminated with a base material interposed therebetween, or a pressure-sensitive adhesive sheet made of one pressure-sensitive adhesive layer and having no base material.

Although the case where ultraviolet rays are irradiated with the second coating layer 54 exposed has been described above, the present invention is not limited to this. Before irradiating with ultraviolet rays, the base material is polymerized by attaching a release sheet to the surface of the uppermost coating layer (second coating layer 54 in FIG. 2 (c)) and blocking the coating layer from the atmosphere. In doing so, the polymerization reaction is not inhibited by oxygen, and the strength of the formed pressure-sensitive adhesive layer becomes higher.
Further, if the pressure-sensitive adhesive sheet 50 after ultraviolet irradiation is heated and stored at a temperature of about 50 ° C. for 24 hours or more, the network structure of the base material further develops in the first and second pressure-sensitive adhesive layers 53 and 57. The strength of the sheet 50 becomes higher.

  T-butyl acrylate as the first resin component, phenoxyethyl acrylate as the second resin component, a third resin component having the composition shown in Table 1 below, a crosslinking agent, a tackifier, and photopolymerization. Initiators were blended at the blending ratios shown in Table 1 below, and pressure-sensitive adhesive compositions of Examples 1 to 6 were obtained.

  In Examples 1 and 2, a resin solution obtained by adding acrylic acid to 2-ethylhexyl acrylate, which is an acrylic monomer, was used as the third resin component. In Examples 3 and 5, a resin solution obtained by adding acrylic acid to butyl acrylate, which is an acrylic monomer, was used as the third resin component. In Examples 4 and 6, a resin solution composed of 30% by weight of 2-ethylhexyl acrylate as an acrylic monomer, 66% by weight of butyl acrylate as an acrylic monomer, and 4% by weight of acrylic acid was polymerized. A material in which the content of an acrylic polymer obtained by polymerizing two kinds of acrylic monomers and acrylic acid was about 25% by weight of the entire resin liquid was used.

  Further, as apparent from Table 1 above, in the pressure-sensitive adhesive compositions of Examples 1 and 5, 20 parts by weight of the first and second resin components were added to 100 parts by weight of the base material, respectively. The amount of the first and second resin components added to the whole is 20% by weight. In Examples 2 and 3, 10 parts by weight of the first resin component and 20 parts by weight of the second resin component are added to 100 parts by weight of the base material, and the amount of the first resin component added to the whole base material is 10% by weight and the amount of the second resin component added is 20% by weight. In Example 4, 5 parts by weight of the first and second resin components are added to 95.7 parts by weight of the base material, and the amount of the first and second resin components added to the whole base material is about 5.2% by weight. In Example 6, 2.5 parts by weight of the first and second resin components are added to 95.4 parts by weight of the base material, and the amount of the first and second resin components added to the whole base material is Each is about 2.6%.

  Examples of the photopolymerization initiator include an initiator PO (a mixture of an aromatic photopolymerization initiator and a phosphine oxide photopolymerization initiator), and trade names “Darocur 1173” manufactured by Ciba Specialty Chemicals Co., Ltd. ”And the trade name“ Irgacure 819 ”, and as tackifiers, the product name“ KE311 ”manufactured by Arakawa Chemical Co., Ltd., a hydrogenated rosin, and Yasuhara Chemical Co., Ltd., a terpene phenol, are used. Product name “U115” and an acrylic tackifier.

As the main crosslinking agent, trade name “TMXDI” manufactured by Takeda Pharmaceutical Co., Ltd. and trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd. were used. “TMXDI” is trimethylxylerin diisocyanate, and “Coronate L” is a TDI-based isocyanate-modified crosslinking agent.
Using the pressure-sensitive adhesive compositions of Examples 1 to 6, the pressure-sensitive adhesive sheets 50 having a film thickness of 150 μm were respectively produced in the steps of FIGS. 2A to 2D, and the pressure-sensitive adhesive sheet 50 was further heated at 50 ° C. for 72 hours. It preserve | saved and the adhesive sheet 50 of Examples 1-6 was obtained.
Apart from this, as comparative examples, the pressure-sensitive adhesive compositions of Comparative Examples 1 to 13 were prepared at the blending ratios shown in Table 2 below, and Comparative Examples 1 to 13 were performed under the same conditions as in Example 1 using the PSA composition. A pressure-sensitive adhesive sheet was prepared.

In addition, Comparative Examples 1-5 is a case where an adhesive composition is produced without using phenoxyethyl acrylate, and Comparative Examples 6-8 are cases where an adhesive composition is produced without using t-butyl acrylate. . Comparative Examples 9 and 10 are cases where the addition amount of t-butyl acrylate was 30 parts by weight with respect to 100 parts by weight of the base material, and Comparative Examples 11 and 12 were those where the addition amount of phenoxyethyl acrylate was 100% by weight of the base material. It is a case where it is 30 weight part with respect to a part. Comparative Example 13 is a case where neither phenoxyethyl acrylate nor t-butyl acrylate was used.
Using the pressure-sensitive adhesive sheet 50 of Examples 1 to 6 and the pressure-sensitive adhesive sheets of Comparative Examples 1 to 13, the following “retention force test”, “peel strength test”, “curved surface adhesion test”, and “constant load” "Peel test" was performed.

[Retention force test]
The adhesive sheet 50 of Examples 1-6 is each affixed to the end of the rectangular-shaped 1st sticking target object 91, and as shown in FIG. After overlapping one end of the attachment object 92 and one end of the first attachment object 91, the first and second attachment objects 91 and 92 are moved by reciprocating a roller having a weight of 2 kg. 6 types of test pieces 90 were produced by bonding.
Here, a stainless steel plate (hereinafter abbreviated as SUS) was used as the first sticking object 91, and a polyethylene terephthalate film (hereinafter abbreviated as PET) having a film thickness of 25 μm was used as the second sticking object 92. . The pressure-sensitive adhesive sheet 50 was a square having a side of 25 mm.

  Next, under a different temperature condition of 40 ° C. and 100 ° C., a load of 1 kg is applied to the other end of the second sticking object 92, and the first and second sticking objects 91, 92 are left after one hour. The magnitude | size (mm) of the shift | offset | difference which arises in the part which stuck, or the time which the 2nd sticking target object 92 peeled was measured, respectively.

[Peel Strength Test] The first and second sticking objects 91 and 92 were bonded together in the same process as the holding power test, and left at room temperature for 1 hour to obtain a test piece 90. Here, a rectangular sheet having a length of 70 mm and a width of 20 mm was used as the adhesive sheet 50. Moreover, as the 2nd sticking target object 92, the same PET as what was used for the holding power test is used, and as the 1st sticking target object 91, SUS, an acrylonitrile butadiene styrene resin film (henceforth, ABS). A total of four types of test pieces were prepared for each of Examples 1 to 6, using four types of materials (abbreviated), polystyrene resin film (hereinafter abbreviated as PS), and polypropylene (hereinafter abbreviated as PP).

  Using these test pieces, as shown in FIG. 6, the end opposite to the side attached to the pressure-sensitive adhesive sheet 50 of the second object to be attached 92 is bent at 180 ° C. to pull the end. Pulling was performed at a speed of 300 mm / min, and the peel strength when the second sticking object 92 was peeled from the first sticking object 91 was measured. The measurement atmosphere was a temperature of 23 ° C. ± 2 ° C. and a relative humidity of 65 ± 5%.

[Curved surface adhesion test]
A plate-like first sticking object 91 having a film thickness of 2 mm and a length of 200 mm and a plate-like second sticking object 92 having a film thickness of 0.5 μm, a length of 20 mm, and a width of 150 mm are prepared. As shown to Fig.7 (a), after bonding the 1st, 2nd sticking target objects 91 and 92 in the state which the adhesive sheet 50 adhered to the whole one surface of the second sticking target object 92, temperature A test piece 90 was left for 24 hours under conditions of 23 ° C. ± 2 ° C. and relative humidity 65 ± 5%.

  Here, the 2nd sticking target object 92 is located in the center position of the 1st sticking target object 91, and the both ends which do not overlap with the 2nd sticking target object 92 of the 1st sticking target object 91 The length of each was 25 mm. Moreover, an aluminum plate is used as the first sticking object, an aluminum plate is used as the second sticking object 92, and three types of ABS, PS, and acrylic plate are used as the first sticking object 91. A total of three types of test pieces 90 were prepared for each of Examples 1 to 6.

  Next, each test piece 90 is bent under a temperature condition of 50 ° C. so that the distance from one end to the other end of the first object 91 is 190 mm (FIG. 7B), and the state is maintained for 24 hours. After maintaining, each test piece 90 was observed, and the size (unit: mm) of the float generated at the end of the second sticking object 92 was measured. Moreover, the case where the magnitude | size of a float was 10 mm or more was evaluated as "x".

[Constant load peel test]
The test piece 90 prepared in the above “peel strength test” is arranged with the surface to which the second object 92 is adhered facing downward, and the second paste is applied in the same measurement atmosphere as the “peel strength test”. After pulling the end of the object 92 opposite to the side adhered to the adhesive sheet 50 with a load of 100 g in the vertical direction (FIG. 8) and maintaining this state for 24 hours, the second object to be adhered The distance (peeling distance, unit: mm) at which the object 92 is peeled from the surface of the first object 91 is measured.

  About the said Examples 1-6, the result of a "holding force test" and a "peel strength test" is described in the following Table 3, the result of a "curved surface adhesion test" is shown in the following Table 4, and the result of a "constant load test" is shown Each is described in Table 5 below. Moreover, about Comparative Examples 1-13, the result of "holding force test" and "peel strength test" is described in the following Table 6, the result of "curved surface adhesion test" is shown in the following Table 7, and the result of "constant load test" Are described in Table 8 below.

The “holding force test” indicates that the smaller the value is, the larger the holding force is. The “peel strength test” indicates that the larger the value is, the higher the peel strength is. The “curved surface adhesion test” indicates that the smaller the value, the higher the resilience resistance and flexibility of the adhesive layer, and the “constant load peel test” indicates that the smaller the value, the stronger the static load.
Also, AF, CF, and J in the above table indicate the state when the adhesive sheet 50 is peeled off, AF indicates interfacial failure (Adhesion Failure), and CF indicates cohesive failure (Cohesive Failure).

As can be seen from Tables 3 and 8 above, the adhesive sheets 50 of Examples 1 to 6 have high evaluation results in the “holding force test”, “peel strength test”, “curved surface adhesion test”, and “constant load test”, respectively. was gotten.
On the other hand, Comparative Examples 3 and 4 which do not contain phenoxyethyl acrylate and Comparative Examples 6 to 8 which do not contain t-butyl acrylate have a low holding power so that the second object 92 cannot be held for one hour. In the “strength test”, all the breaks in the examples were interfacial fracture (AF), whereas Comparative Examples 3, 4, and 6 to 8 were cohesive fracture (CF) in which the adhesive layer itself was destroyed. It can be seen that the strength is low.

Further, Comparative Example 5, which does not have phenoxyethyl acrylate but has a large amount of tackifier added, showed sufficient holding power due to its high tackiness, but the peel mode of peel strength was CF. It can be seen that the strength of the adhesive layer is low.
In addition, any one of Comparative Examples 9 to 12 in which the addition amount of phenoxyethyl acrylate and the addition amount of t-butyl acrylate is 30 parts by weight or more with respect to 95 parts by weight of the base material, or phenoxyethyl acrylate and t-butyl acrylate, respectively. Comparative Examples 1, 2 and 6 to which only one of them is added have low evaluation for “curved surface adhesion” and “constant load peeling”, and it can be seen that the adhesive layer has low flexibility and low adhesive strength.

  Although the case where butyl acrylate and 2-ethylhexyl acrylate are used as the third resin component has been described above, the present invention is not limited to this. For example, an acrylic monomer such as n-propyl acrylate, nonyl acrylate, isooctyl acrylate, or a mixture of these acrylic monomers and an acrylic polymer can be used.

The crosslinking main agent is not limited to an isocyanate compound, and various crosslinking agents such as epoxy resins, various acrylates, polyfunctional monomers having functional groups such as vinyl groups, and oligomers thereof can be used. In addition to hydroxypropyl acrylate, for example, acrylic acid ester derivatives such as 2-hydroxyethyl acrylate, oligoester acrylates such as phenoxydiethylene glycol acrylate, monomers having a hydroxyl group, a carboxyl group, an amine group, and the like can be used. .
As the tackifier, rosin ester resin, rosin-modified phenol resin, various terpene resins, low molecular weight butyl rubber, polybutene, acrylic resin, xylene resin, and the like can also be used.

As a raw material of the nonwoven fabric used for the base material 55, various natural fibers, such as synthetic fibers, such as glass fiber, an acrylic fiber, nylon fiber, a polyester fiber, or a cotton fiber, can be used, for example. When a non-woven fabric is used as the base material 55 and the pressure-sensitive adhesive composition is applied onto the base material 55 as shown in FIGS. 2 and 4, it is preferable that the pressure-sensitive adhesive composition is not impregnated. Moreover, the base material 55 is not limited to a nonwoven fabric, For example, various resin films, such as a polyester film and an OPP (biaxially stretched polypropylene) film, can also be used. In any case, the substrate 55 is preferably a substrate having a high ultraviolet transmittance.
Moreover, it is also possible to add various additives, such as antiaging agent and a coloring agent, to the adhesive composition of this invention.

The figure for demonstrating an example of the manufacturing apparatus used for manufacture of the adhesive sheet of this invention (a)-(d): The figure for demonstrating an example of the manufacturing process of the adhesive sheet of this invention. The figure for demonstrating the other example of the manufacturing apparatus used for manufacture of the adhesive sheet of this invention (a)-(c): The figure for demonstrating the other example of the manufacturing process of the adhesive sheet of this invention. Diagram for explaining the holding power test method Diagram for explaining the test method of peel strength test (a), (b): diagrams for explaining the test method of the curved surface adhesion test Diagram for explaining the test method of the constant load peel test

Explanation of symbols

50, 70 ... Adhesive sheets 51, 71 ... Support (peeling tape)
52, 72 ... first coating layer 53, 73 ... first adhesive layer 54, 74 ... second coating layer 55, 75 ... substrate (nonwoven fabric)
57, 77 …… Second adhesive layer

Claims (6)

A method for producing a pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive sheet having at least two pressure-sensitive adhesive layers and having a substrate disposed between the pressure-sensitive adhesive layers,
Applying a pressure-sensitive adhesive composition to at least one surface of the support, and forming a first coating layer;
Disposing the substrate on the first coating layer;
Applying a pressure-sensitive adhesive composition on the substrate and forming a second coating layer;
Irradiate one or both of the surface on which the support is disposed and the surface on which the second coating layer is disposed, to cure the first and second coating layers. Forming the first and second adhesive layers;
Heating the first and second adhesive layers,
To the pressure-sensitive adhesive composition, a base material containing acrylate, a photopolymerization initiator that polymerizes the base material by ultraviolet irradiation, a cross-linking agent that forms a cross-linked structure, and a tackifier that imparts tackiness. Contain,
In the acrylate contained in the base material ,
(A) a first acrylate composed of t-butyl acrylate;
(B) a second acrylate comprising phenoxyethyl acrylate,
(C) an acrylic polymer obtained by polymerizing acrylic acid or 2-ethylhexyl acrylate, butyl acrylate and acrylic acid ,
The addition amount of the first acrylate is 2.5 wt% or more and 20 wt% or less of the whole base material,
The addition amount of the second acrylate is 2.5 wt% or more and 20 wt% or less of the whole base material,
Before SL crosslinking agent, production method of the adhesive sheet to an isocyanate compound as a crosslinking base resin. A method for producing a pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive sheet having at least two pressure-sensitive adhesive layers and having a substrate disposed between the pressure-sensitive adhesive layers,
Applying a pressure-sensitive adhesive composition to at least one surface of the support, and forming a first coating layer;
Applying a pressure-sensitive adhesive composition to one surface of the substrate and forming a second coating layer;
Adhering the surface of the first coating layer on the support and the surface of the substrate on which the second coating layer is not formed;
Irradiate one or both of the surface on which the support is disposed and the surface on which the second coating layer is disposed to cure the first and second coating layers. Forming the first and second adhesive layers;
Heating the first and second adhesive layers,
To the pressure-sensitive adhesive composition, a base material containing acrylate, a photopolymerization initiator that polymerizes the base material by ultraviolet irradiation, a cross-linking agent that forms a cross-linked structure, and a tackifier that imparts tackiness. Contain,
In the acrylate contained in the base material ,
(A) a first acrylate composed of t-butyl acrylate;
(B) a second acrylate comprising phenoxyethyl acrylate,
(C) an acrylic polymer obtained by polymerizing acrylic acid or 2-ethylhexyl acrylate, butyl acrylate and acrylic acid ,
The addition amount of the first acrylate is 2.5 wt% or more and 20 wt% or less of the whole base material,
The addition amount of the second acrylate is 2.5 wt% or more and 20 wt% or less of the whole base material,
Before SL crosslinking agent, production method of the adhesive sheet to an isocyanate compound as a crosslinking base resin. The manufacturing method of the adhesive sheet of any one of Claim 1 or Claim 2 which adds a hydroxypropyl acrylate to the said crosslinking agent as a crosslinking adjuvant. The method for producing a pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein 2-ethylhexyl acrylate, butyl acrylate, n-propyl acrylate, nonyl acrylate, isooctyl acrylate or a mixture thereof is contained in the acrylate. The manufacturing method of the adhesive sheet of any one of Claim 1 thru | or 4 containing a rosin, terpene phenol, or an acrylic tackifier as the said tackifier. The method for producing a pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the first and second pressure-sensitive adhesive layers are heated for 24 hours or more.

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