JP2019059931A - Adhesive tape roll and optical film laminate - Google Patents

Abstract

To provide an adhesive tape roll that has a light developing capability, and shows little change in adhesiveness of an adhesive tape regardless of the feeding position, and an optical film laminate.SOLUTION: An adhesive tape roll has a rolled-up adhesive tape which has a substrate layer and an adhesive layer. In the adhesive tape roll, the substrate layer has a release agent (a), and the adhesive layer has a release agent (b).SELECTED DRAWING: None

Description

The present invention relates to a pressure-sensitive adhesive tape roll and an optical film laminate which are light spreadable and in which the change in adhesion of the pressure-sensitive adhesive tape is small regardless of the delivery position.

Adhesive tapes are used in various industrial fields because they can be easily joined. In the construction sector, temporary fixing of curing sheets, bonding of interior materials, etc. In the automotive sector, fixing of interior parts such as sheets and sensors, fixing of exterior parts such as side moldings and side visors, etc. An adhesive tape is used for bonding a module to a housing. In addition, as a surface protection tape for protecting the surface of a member such as an optical device, a metal plate, a painted metal plate, a resin plate, a glass plate, etc., a substrate layer and a pressure-sensitive adhesive layer laminated on one surface thereof The adhesive tape which has these is used (for example, patent documents 1-3).

Japanese Patent Application Laid-Open No. 1-129085 Japanese Patent Application Laid-Open No. 6-1958 JP-A-8-12952

The pressure-sensitive adhesive tape is usually produced by a co-extrusion method or the like, and then shipped in the form of a pressure-sensitive adhesive tape roll wound in a roll, fed out from the pressure-sensitive adhesive tape roll as appropriate, and cut into an appropriate shape. In FIG. 1, the schematic diagram explaining delivery of the adhesive tape from an adhesive tape roll is shown.
In FIG. 1, the adhesive tape 2 is composed of a base layer 21 and an adhesive layer 22. The adhesive tape roll 1 is formed by winding the adhesive tape 2. The adhesive tape 2 is fed from the adhesive tape roll 1 and used for use.

While the adhesive tape can exhibit the adhesive force required for each application, the force (deployment force) required for feeding from the adhesive tape roll is preferably smaller (so-called "light spreadability").
However, despite the same adhesive tape, a large difference may occur in the adhesive force of the adhesive tape drawn from the adhesive tape roll. That is, while the adhesive tape drawn out from the vicinity of the outside of the roll of the adhesive tape roll shows high adhesive strength, the adhesive tape drawn out from the vicinity of the core becomes lower in adhesive strength and improved from the viewpoint of quality stability. There is room for

An object of the present invention is to provide a pressure-sensitive adhesive tape roll and an optical film laminate which are light spreadable and in which the change in adhesion of the pressure-sensitive adhesive tape is small regardless of the delivery position.

This invention is an adhesive tape roll which wound the adhesive tape which has a base material layer and an adhesive layer in roll shape, Comprising: The said base material layer is a mold release agent (a), The said adhesive layer releases a mold It is an adhesive tape roll containing an agent (b).
The present invention will be described in detail below.

The present inventors examined the cause of the large difference in the adhesive strength of the adhesive tape drawn from the adhesive tape roll. As a result, the present inventors have found that the cause is the transfer bias of the release agent contained in the substrate layer.
In the pressure-sensitive adhesive tape roll, in order to ensure light spreadability, a release agent is blended in the base material layer. When the base layer is compounded with a release agent, the release agent bleeds out from the base layer to form a very thin release layer on the surface of the base layer. In the pressure-sensitive adhesive tape roll, the release layer formed on the surface of the base material layer contacts the pressure-sensitive adhesive surface of the wound pressure-sensitive adhesive layer. Thereby, the light spreadability of an adhesive tape roll is securable.
In such a light-spreading adhesive tape roll, a part of the release layer is a pressure-sensitive adhesive because the release layer formed on the surface of the base layer contacts the adhesive surface of the wound pressure-sensitive adhesive layer. May be transferred to the surface of the layer. Although the adhesive force of the adhesive tape is lowered by the transfer of the release layer, it has been considered that there is no practical problem if an adhesive layer having a certain adhesive force or more is selected. However, the present inventors have determined that the degree of transfer of such a release layer largely varies depending on the delivery position. The pressure-sensitive adhesive tape wound on the pressure-sensitive adhesive tape roll is subjected to a stress called "rolling". This stress is not constant in the adhesive tape roll, but is strong near the core and weak near the outside of the winding. Therefore, in the vicinity of the winding core, the release layer is strongly pressed by the adhesive surface of the pressure-sensitive adhesive layer, and the degree of transfer becomes larger, while the stress to be pressed is weaker in the vicinity of the outside, and the degree of transfer is more It becomes smaller. As a result, in the pressure-sensitive adhesive tape fed out from the vicinity of the winding, the release layer is not transferred so much on the surface of the pressure-sensitive adhesive layer and the adhesive strength is high. It is considered that a large amount of the release layer is transferred to the surface of the agent layer and the adhesion becomes low.
The present inventors have not only blended the mold release agent into the base material layer, but also blended the mold release agent into the pressure-sensitive adhesive layer, so that they are lightly spreadable and adhesive regardless of the delivery position. It has been found that an adhesive tape roll with less change can be provided. Above all, the present inventors have found that the difference between the SP values of the base resin constituting the base layer and the release agent contained in the base layer and / or the base resin and the adhesive layer constituting the adhesive layer. It is found that by adjusting the difference in SP value with the release agent contained to a specific value or more, appropriate adhesion and reduction in change in adhesion depending on the delivery position can be more reliably achieved, and the present invention is completed. It came to

The pressure-sensitive adhesive tape roll of the present invention is obtained by winding a pressure-sensitive adhesive tape having a base material layer and a pressure-sensitive adhesive layer in a roll.
The base layer contains a release agent (a). In such a substrate layer, the release agent bleeds out to form a very thin release layer on the surface of the substrate layer, so it is possible to obtain a light-spreading adhesive tape roll.

In the base layer, the difference ΔSP1 of the SP (solubility parameter) value between the base resin constituting the base layer and the release agent (a) is preferably 0.1 or more.
By adjusting the above ΔSP1 to the above value or more, it is possible to achieve both the appropriate adhesive force and the reduction of the change in the adhesive force depending on the extended position more reliably. From the same viewpoint, ΔSP1 is more preferably 0.4 or more, still more preferably 0.6 or more, still more preferably 0.8 or more, particularly preferably 1 or more, and for example, 1.2 or more.
The upper limit of the ΔSP1 is not particularly limited, but is preferably 3.0 or less because the compatibility between the base resin constituting the base layer and the release agent (a) decreases if the ΔSP1 is too high.

In the present specification, ΔSP1 is defined by the following formula.
ΔSP1 = | SP value of mold release agent (a) −SP value of base resin constituting the base layer |

In the present specification, the SP value is a solubility parameter (solubility parameter), and is defined by the following equation. The SP value can be determined by the method of Mr. Okitsu described in the Adhesion August issue [Volume 40, Issue 8, Volume 436, P6-14]: Polymer Journal.
SP = (ΔE / V) ^1/2
Here, ΔE represents evaporation energy, and V represents molar volume. Therefore, since ΔE / V is the cohesive energy density, it can be said that the SP value is an amount related to the cohesive energy of the substance.

The release agent (a) is not particularly limited as long as it is generally used for the base material layer of the pressure-sensitive adhesive tape, and, for example, an amine release agent, a silicon release agent, a fluorine release agent, and a hydrocarbon Examples include mold release agents and metal soap mold release agents. These release agents may be used alone or in combination of two or more. Among them, amine-based release agents, silicone-based release agents, fluorine-based release agents or metal soap-based release agents are preferable, and amine-based release agents are more preferable. Among the amine-based release agents, fatty acid bisamides (saturated fatty acid bisamides and unsaturated fatty acid bisamides) are preferable from the viewpoint of further reducing the light spreadability and the change in the adhesive strength of the adhesive tape, and from the viewpoint of adhesive residue reduction. And saturated fatty acid bisamides are more preferred.
Although the SP value of these release agents is not particularly limited, the SP value of amine-based release agents is usually about 9.0 to 10.0, and the SP value of silicon-based release agents is usually 7.0 The SP value of the fluorine-based release agent is usually about 7.0 to 8.0, and the SP value of the metal soap-based release agent is usually about 8.0 to 9.0 .

Examples of the saturated fatty acid bisamides include saturated fatty acid aliphatic bisamides such as ethylenebisstearic acid amide, methylenebisstearic acid amide, hexamethylenebisstearic acid amide, m-xylylene bisstearic acid amide, N-N'- Saturated fatty acid aromatic bisamides such as distearyl isophthalic acid amide may be mentioned. Examples of unsaturated fatty acid bisamides include ethylene bis oleic acid amide, ethylene bis erucic acid amide, hexamethylene bis oleic acid amide, N, N'-dioleyl sebacic acid amide and the like. Among the saturated fatty acid aliphatic bisamides, ethylenebisstearic acid amide is preferred. Among the saturated fatty acid aromatic bisamides, m-xylylene bis-stearic acid amide is preferred. These saturated fatty acid bisamides may be used alone or in combination of two or more.

As said silicone type mold release agent, a silicone oil, a silane coupling agent, a silicone polymer etc. are mentioned, for example. Among them, a polymer obtained by graft polymerizing a reactive polyorganosiloxane to a polyolefin resin is preferable.
As said fluorine type mold release agent, the (meth) acrylic acid ester etc. which have a C1-C18 perfluoroalkyl group are mentioned, for example. It is more preferable that the said C1-C18 perfluoroalkyl group is C1-C6. The above-mentioned perfluoroalkyl group having 1 to 18 carbon atoms may be linear or branched. These may be used alone or in combination of two or more.
Examples of the hydrocarbon-based release agent include synthetic wax and natural wax. Among them, PE wax and PP wax are preferable.
As said metal soap type | mold mold release agent, the metal salt (salt of metals other than an alkali metal) etc. of a long chain fatty acid or an organic acid etc. are mentioned, for example.

The base resin which comprises the said base material layer is not specifically limited, For example, polyolefin resin, polyester resin, acrylic resin, polyvinyl chloride resin etc. are mentioned. Among them, a polyolefin resin, a polyester resin or an acrylic resin is preferable, and a polyolefin resin is more preferable, because the ΔSP1 can be easily adjusted to the value or more.
Although the SP value of these base resins is not particularly limited, the SP value of polyolefin resin is usually about 7.5 to 8.5, and the SP value of polyester resin is usually about 10 to 12, and acrylic The SP value of the base resin is usually about 9 to 10.

The said polyolefin resin is not specifically limited, Conventionally well-known polyolefin resin can be used, For example, polypropylene (PP) resin, polyethylene (PE) resin, etc. are mentioned.
Examples of the polypropylene resin include homopolypropylene, random polypropylene, block polypropylene and the like. Examples of the polyethylene resin include high pressure low density polyethylene, linear low density polyethylene, high density polyethylene and the like. Among them, polypropylene resins are preferable from the viewpoints of transparency, rigidity, and heat resistance, and homopolypropylene or a copolymer of propylene and at least one α-olefin is more preferable.

The polyester-based resin is not particularly limited, and examples thereof include polybutylene terephthalate and polyethylene terephthalate. Among them, polybutylene terephthalate is preferable because of easy low temperature molding.

The said acrylic resin is not specifically limited, For example, a polymethacryl, an acryl copolymer, etc. are mentioned. Among them, acrylic copolymers are preferable because of their excellent film formability.

The content of the releasing agent (a) in the base layer is not particularly limited, but a preferable lower limit is 0.5 parts by weight and a preferable upper limit is 4 parts by weight with respect to 100 parts by weight of the base resin constituting the base layer. It is. When the content of the release agent (a) is within this range, the thickness of the release layer formed by bleeding out from the base layer is about 1 to 100 nm, and the light developability of the adhesive tape roll is secured. While, it is possible to prevent the lowering of the adhesive strength of the adhesive layer due to the excessive transfer. From the same viewpoint, the lower limit of the content of the releasing agent (a) is more preferably 0.6 parts by weight, more preferably 3 parts by weight, still more preferably 0.8 parts by weight, still more preferably the upper limit The lower limit is 2 parts by weight, and the still more preferable lower limit is 1 part by weight, and the still more preferable upper limit is 1.8 parts by weight.

The above base material layer is an additive such as an antistatic agent, an antioxidant, a weathering agent, a crystal nucleating agent, and a resin modifier such as polyolefin, polyester, polyamide, elastomer, etc., as long as the effects of the present invention are not impaired. You may contain.

Although the thickness of the said base material layer is not specifically limited, A preferable minimum is 20 micrometers and a preferable upper limit is 200 micrometers. When the thickness of the base material layer is in this range, the handleability is excellent. The more preferable lower limit of the thickness of the base material layer is 25 μm, and the more preferable upper limit is 180 μm.

The pressure-sensitive adhesive layer contains a release agent (b). As a result, it is possible to provide an adhesive tape roll with little change in adhesive force regardless of the delivery position.
Although the reason for this is not necessarily clear, it is considered that the irregular transfer of the release layer from the substrate layer side can be prevented by blending the release agent also in the pressure-sensitive adhesive layer.

As a mold release agent (b) contained in the said adhesive layer, the thing similar to the mold release agent (a) contained in the said base material layer can be used.
In addition, the mold release agent (a) contained in the said base material layer and the mold release agent (b) contained in the said adhesive layer may be the same kind, and may be different.

In the pressure-sensitive adhesive layer, the difference ΔSP2 of the SP (solubility parameter) value between the base resin constituting the pressure-sensitive adhesive layer and the releasing agent (b) is preferably 0.1 or more.
By adjusting the above ΔSP 2 to the above value or more, it is possible to achieve both the appropriate adhesive power and the reduction of the change in the adhesive power due to the extended position more reliably. From the same viewpoint, ΔSP2 is more preferably 0.4 or more, still more preferably 0.6 or more, still more preferably 0.8 or more, particularly preferably 1 or more, and for example, 1.2 or more.
The upper limit of the ΔSP2 is not particularly limited, but is preferably 3.0 or less because the compatibility between the base resin constituting the pressure-sensitive adhesive layer and the release agent (b) decreases if the ΔSP2 is too high.

In the present specification, ΔSP2 is defined by the following equation.
ΔSP2 = | SP value of release agent (b) −SP value of base resin constituting adhesive layer |

Although the base resin which comprises the said adhesive layer is not specifically limited, For example, a styrene-type elastomer, an acryl-type elastomer, a urethane type elastomer, an olephen-type elastomer etc. are mentioned. Among them, high adhesive strength (initial adhesive strength) can be exhibited, and the hardness can be easily adjusted by the styrene content, and furthermore, the ΔSP 2 can be easily adjusted to the above value or more, and thus, a styrene elastomer Is preferred.
In addition, although SP value of these base resins is not specifically limited, SP value of a styrene-type elastomer is about 5.5-9.0 normally.

The styrene-based elastomer is not particularly limited, and, for example, styrene ethylene propylene styrene block copolymer (SEPS), hydrogenated styrene butadiene rubber (HSBR), styrene ethylene butylene styrene block copolymer (SEBS), styrene ethylene propylene block Copolymer (SEP), styrene ethylene butylene block copolymer (SEB), styrene isoprene block copolymer (SI), styrene isoprene styrene block copolymer (SIS), styrene butadiene block copolymer (SB), styrene Butadiene styrene block copolymer (SBS) etc. are mentioned.

Among the above-mentioned styrene-based elastomers, styrene-ethylene-propylene-styrene block copolymer (SEPS), hydrogenated styrene-butadiene rubber (HSBR), styrene-ethylene-butylene, because it is easy to adjust to an appropriate viscoelasticity in designing primary structure of polymer. Styrene block copolymers (SEBS) are particularly preferred.

The content of the releasing agent (b) in the pressure-sensitive adhesive layer is not particularly limited, but a preferable lower limit is 0.5 parts by weight and a preferable upper limit is 4 parts by weight with respect to 100 parts by weight of the base resin constituting the pressure-sensitive adhesive layer. It is. When the content of the release agent (b) is in this range, it is possible to reduce the change in the adhesive strength depending on the feeding position while securing an appropriate adhesive strength. From the same viewpoint, the lower limit of the content of the releasing agent (b) is preferably 0.6 parts by weight, more preferably 3 parts by weight, still more preferably 0.8 parts by weight, and still more preferably the upper limit The lower limit is 2 parts by weight, and the still more preferable lower limit is 1 part by weight, and the still more preferable upper limit is 1.8 parts by weight.

The content of the release agent (b) in the adhesive layer and the content of the release agent (a) in the base layer are in the range of 1/3 to 3/1 by weight ratio Is preferably, and more preferably in the range of 1/2 to 2/1, for example, in the range of 2/3 to 3/2. When the ratio of the two is within the above range, it is possible to achieve both the appropriate adhesive force and the reduction of the change in the adhesive force depending on the extended position more reliably.

The pressure-sensitive adhesive layer may contain, for example, an additive such as a tackifier, an antioxidant, a softener, or an adhesive agent for the purpose of controlling adhesion and the like.
Although content of the said tackifier in the said adhesive layer is not specifically limited, It is preferable that it is 40 weight part or less with respect to 100 weight part of base resins which comprise the said adhesive layer.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, but a preferable lower limit is 2 μm and a preferable upper limit is 30 μm. When the thickness of the pressure-sensitive adhesive layer is in this range, it is possible to achieve both sufficient adhesion to the adherend and handleability. The more preferable lower limit of the thickness of the pressure-sensitive adhesive layer is 2.5 μm, and the more preferable upper limit is 20 μm.

The adhesive tape roll of this invention winds the said adhesive tape in roll shape.
The pressure-sensitive adhesive tape roll of the present invention may be obtained by winding only the pressure-sensitive adhesive tape without using the core material, or may be obtained by winding the pressure-sensitive adhesive tape around the core material.

The winding length of the pressure-sensitive adhesive tape roll of the present invention is not particularly limited, but the effect of the present invention is particularly exhibited when the winding length is 300 m or more. This is considered to be because as the winding length is longer, the difference in stress due to "roll tightening" between the vicinity of the winding core and the vicinity of the winding outer side is increased. The winding length is more preferably 500 m or more.

In the pressure-sensitive adhesive tape roll of the present invention, the concentration change ratio of the concentration of the release agent on the outermost surface of the pressure-sensitive adhesive layer on the core side sample and the concentration of the release agent on the outermost surface of the pressure-sensitive adhesive layer on the winding outer side sample is 30 It is preferable that it is% or less.
The core side sample means a sample cut out at a position up to 10 m from the end on the core side, and the winding outer side sample means a sample cut out at a position up to 10 m from the end outside the winding side Do. The density change rate is calculated by the following equation.
Concentration change rate (%) = | concentration of release agent on the outermost surface of the pressure-sensitive adhesive layer on the core side sample−concentration of release agent on the outermost surface of the pressure-sensitive adhesive layer on the winding outer side | / adhesive layer on top of the winding outer side sample Release agent concentration on surface × 100

The concentration of the release agent on the outermost surface of the pressure-sensitive adhesive layer can be measured, for example, by time-of-flight secondary ion mass spectrometry (TOF-SIMS).

In the pressure-sensitive adhesive tape roll of the present invention, it is preferable that the adhesive strength change ratio between the adhesive strength of the core side sample and the adhesive strength of the winding outer side sample is 50% or less. The adhesive strength change rate is more preferably 20% or less, still more preferably 18% or less, still more preferably 16% or less, particularly preferably 14% or less, and 12% or less It is particularly preferred that it is 10% or less. The adhesive tape roll with few changes of the adhesive force of an adhesive tape irrespective of a delivery position as the said adhesive force change rate is below the said upper limit can be provided.
The adhesive force change rate is determined, for example, as follows. First, a pressure-sensitive adhesive tape of a winding outer side sample or a core side sample cut into a 25 mm width is attached to an acrylic resin plate having a thickness of 130 μm to prepare a test piece. In addition, an adhesive tape is affixed on an acrylic resin board at a speed of 300 mm / min using a 2 kg pressure-bonding rubber roller at a room temperature of 23 ° C. and a relative humidity of 50%. Next, in accordance with JIS Z 0237, the adhesive tape is peeled off at a speed of 300 mm / min, and the adhesion (180 ° peel strength) of the winding outer side sample and the core side sample is measured. From the obtained data, the adhesive force change rate is calculated by the following equation.
Adhesive force change rate (%) = | Adhesiveness of core side sample-Adhesiveness of roll outer side sample | Adhesive power of outer roll side sample × 100

The method for producing the pressure-sensitive adhesive tape roll of the present invention is not particularly limited, and a conventionally known method can be used.
As a method of producing the above-mentioned pressure-sensitive adhesive tape, for example, a method of laminating other layers by a known lamination method such as extrusion lamination or extrusion coating on a layer obtained in advance by T-die molding or inflation molding After making a layer into a film independently, the method of laminating | stacking each film obtained by dry lamination etc. is mentioned. From the viewpoint of productivity, co-extrusion molding in which each material of the base layer and the pressure-sensitive adhesive layer is supplied to a multilayer extruder for molding is preferable, and in terms of thickness accuracy, T-die molding is more preferable.
The pressure-sensitive adhesive tape roll of the present invention can be obtained by winding the pressure-sensitive adhesive tape produced in this manner into a roll.

Although the use of the adhesive tape roll of this invention is not specifically limited, It can use suitably especially as a protective film roll for protecting optical films, such as a polarizing plate, retardation film, and a brightness enhancement film. The pressure-sensitive adhesive tape roll of the present invention is light spreadable, and since the change in the adhesive strength of the pressure-sensitive adhesive tape is small regardless of the delivery position, the optical film is surely protected without peeling off the pressure-sensitive adhesive tape. can do.
An optical film laminate in which an adhesive tape and an optical film are bonded, wherein the adhesive tape has a base material layer and an adhesive layer, and the base material layer contains a release agent (a). An optical film laminate wherein the pressure-sensitive adhesive layer contains a releasing agent (b) is also one of the present invention.

According to the present invention, it is possible to provide a pressure-sensitive adhesive tape roll and an optical film laminate which is light spreadable and which has little change in the adhesion of the pressure-sensitive adhesive tape regardless of the delivery position.

It is a schematic diagram explaining delivery of the adhesive tape from an adhesive tape roll.

EXAMPLES The embodiments of the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

<Base resin for adhesive layer>
As base resin of an adhesive layer, what was synthesize | combined by the following synthesis examples 1 and 2, and the commercial item 1 were used. Table 1 shows the base resins of the synthesis examples and the commercially available products.

(1) Synthesis example 1
Into a nitrogen-substituted reaction vessel, 500 parts by weight of degassed and dehydrated cyclohexane, 15 parts by weight of styrene and 5 parts by weight of tetrahydrofuran are charged, and 0.13 parts by weight of n-butyllithium is added at 40 ° C. as a polymerization initiation temperature. Then, temperature increase polymerization was carried out to obtain an aromatic alkenyl polymer block (block A).
After the polymerization conversion of the aromatic alkenyl polymer block reaches about 100%, the reaction solution is cooled to 15 ° C., and 20 parts by weight of styrene as an aromatic alkenyl compound and 1,3-butadiene 65 as a conjugated diene compound Parts by weight were added, and temperature increase polymerization was further performed to obtain a conjugated diene polymer block (block B).
After the polymerization conversion reached almost 100%, 0.06 parts by weight of methyldichlorosilane as a coupling agent was added to carry out a coupling reaction. After the coupling reaction was completed, it was left for 10 minutes while supplying hydrogen gas at a pressure of 0.4 MPa-Gauge.
In the reaction vessel, 0.07 parts by weight of methyldichlorosilane as a coupling agent was added to carry out a coupling reaction. After the coupling reaction was completed, it was left for 10 minutes while supplying hydrogen gas at a pressure of 0.4 MPa-Gauge. GPC analysis of the partially taken out polymer revealed that the weight-average molecular weight was about 150,000, and the coupling ratio (content of the coupled copolymer in the entire copolymer) was 60%. Moreover, when the infrared absorption spectrum of the polymer taken out in part was measured and it computed by the Morelo method, the vinyl bond content rate was 64 mol%.

(2) Synthesis example 2
In a nitrogen-substituted reaction vessel, 500 parts by weight of degassed and dehydrated cyclohexane, 9 parts by weight of styrene and 5 parts by weight of tetrahydrofuran are charged, and 0.13 parts by weight of n-butyllithium is added at 40 ° C. as a polymerization initiation temperature. Then, temperature increase polymerization was carried out to obtain an aromatic alkenyl polymer block (block A).
After the polymerization conversion of the aromatic alkenyl polymer block reaches about 100%, the reaction solution is cooled to 15 ° C., 91 parts by weight of 1,3-butadiene is added, and temperature rising polymerization is further performed to obtain a conjugated diene. A polymer block (block B) was obtained.
After the polymerization conversion reached almost 100%, 0.06 parts by weight of methyldichlorosilane as a coupling agent was added to carry out a coupling reaction. After the coupling reaction was completed, it was left for 10 minutes while supplying hydrogen gas at a pressure of 0.4 MPa-Gauge.
In the reaction vessel, 0.07 parts by weight of methyldichlorosilane as a coupling agent was added to carry out a coupling reaction. After the coupling reaction was completed, it was left for 10 minutes while supplying hydrogen gas at a pressure of 0.4 MPa-Gauge. GPC analysis of the partially taken out polymer revealed that the weight-average molecular weight was about 150,000, and the coupling ratio (content of the coupled copolymer in the entire copolymer) was 60%. Moreover, when the infrared absorption spectrum of the polymer taken out in part was measured and it computed by the Morelo method, the vinyl bond content rate was 64 mol%.

(3) Commercial products 1
A commercially available styrene-ethylene butylene copolymer (manufactured by JSR, trade name "DR1321P") was used as a base resin.

In Table 1, St (A + B) means the total styrene content in block A and block B. Of the total styrene content, the ratio of the styrene content in block A is denoted as St (A), and the ratio of the styrene content in block B is denoted as St (B).

<Release agent>
The following were used as a mold release agent.
Release agent A: Saturated fatty acid amide type release agent, ethylenebisstearic acid amide (EBSA) (manufactured by NOF Corporation, trade name "Alflo H50F")
Release agent B: unsaturated fatty acid amide type release agent, ethylene bis erucic acid amide (manufactured by Nippon Kasei Co., Ltd., trade name "Suripax R")
Release agent C: Hydrocarbon-based release agent, PE wax (manufactured by Honeywell, trade name "ACumist C5")
Release agent D: Metal soap-based release agent, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name "SC-100")
Release agent E: Fluorine-based release agent, trifluoroethyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Light Ester M-3F")
Release agent F: silicone type release agent, silicone graft LDPE (made by Toray Dow Corning, trade name "BY27-202H")

Example 1
5 parts by weight of a tackifier (made by Arakawa Chemical Industry Co., Ltd., trade name "Alcon P100") and 100 parts by weight of a base resin of Synthesis Example 1, an antioxidant (Ciba Specialty Chemicals, trade name: Irganox 1010) 1) 1 part by weight and 1.5 parts by weight of a releasing agent A as a releasing agent were blended to obtain a resin composition for an adhesive layer (in the table, an adhesive composition).
On the other hand, 1.5 parts by weight of a mold release agent A is blended as a mold release agent with 100 parts by weight of a polypropylene resin (manufactured by Prime Polymer Co., Ltd., trade name "J715M"), and a resin composition for base layer (in the table, Base composition) was obtained.
The obtained resin composition for an adhesive layer and the resin composition for a base layer were subjected to a T-die method under the conditions of an extrusion temperature of 200 ° C. and a cast roll temperature of 25 ° C., and the thickness of the base layer was 36 μm, an adhesive layer The pressure-sensitive adhesive tape having a thickness of 4 μm was co-extruded, and the obtained pressure-sensitive adhesive tape was wound with a winding length of 2000 m to obtain a pressure-sensitive adhesive tape roll.

(Examples 2 to 18, Comparative Examples 1 to 5)
A pressure-sensitive adhesive tape roll was obtained in the same manner as in Example 1 except that the composition of the resin composition for an adhesive layer and the resin composition for a base layer was as shown in Tables 2 and 3 in winding length.
As shown in Table 3, in Example 17, a polybutylene terephthalate resin (manufactured by Polyplastics Co., Ltd., trade name "700FP") is used, and in Example 18, an acrylic resin (manufactured by Asahi Kasei Corp., trade name "Delpet, SR8350"). ") Was used.

(Evaluation)
The pressure-sensitive adhesive tape rolls obtained in Examples and Comparative Examples were evaluated as follows.
The results are shown in Tables 2 and 3.

(1) Determination of ΔSP1 and ΔSP2 ΔSP1 (| SP value of mold release agent (a)-SP value of base resin constituting base layer |) and ΔSP2 (| SP value of mold release agent (b)-adhesive The SP value of the base resin constituting the layer |) was calculated. The SP value was determined by the method of Mr. Okitsu described in the Adhesion August issue [Vol. 40, No. 8, No. 436, pp. 6-14]: Polymer Journal.

(2) Evaluation of spreading force According to JIS Z 0237, an adhesive tape was fed out from an adhesive tape roll at a feeding speed of 20 m / min, and a high-speed rewinding force was measured. Based on the obtained measured values, the developing force was determined according to the following criteria.
:: High-speed rewinding force is 2N / 50 mm or less ○: High-speed rewinding force exceeds 2N / 50mm, 3.0N / 50mm or less ×: High-speed rewinding force exceeds 3.0N / 50mm

(3) Evaluation of the concentration of the release agent on the outermost surface of the pressure-sensitive adhesive layer The pressure-sensitive adhesive tape is fed from a pressure-sensitive adhesive tape roll and cut out at a position up to 10 m from the end of the winding outer side The core sample was taken out at a position 10 m from the part. The winding outer side sample and the core side sample were each randomly taken at three or more points.
The concentration of the release agent on the outermost surface of the pressure-sensitive adhesive layer on the outer side sample and the core side sample was measured by time-of-flight secondary ion mass spectrometry (TOF-SIMS).
After averaging the obtained data, the concentration change rate of the release agent on the outermost surface of the pressure-sensitive adhesive layer (| the concentration of the release agent on the outermost surface of the pressure-sensitive adhesive layer on the winding core side sample-the pressure-sensitive adhesive layer most on the winding outer sample Concentration of release agent on the surface | / concentration of release agent on the outermost surface of the pressure-sensitive adhesive layer of the sample on the outside of the winding was calculated × 100).

(4) Evaluation of adhesive force An adhesive tape was fed out from an adhesive tape roll, and the one cut out at a position up to 10 m from the end outside the winding was cut out at a position up to 10 m from the end on the winding core side and the core side. The thing was made into the core side sample.

The adhesive tape of the winding outer side sample or the core side sample cut into a 25 mm width was attached to a 130 μm thick acrylic resin plate to prepare a test piece. A pressure-sensitive adhesive tape was attached to the acrylic resin plate at a speed of 300 mm / min using a 2 kg pressure-bonding rubber roller at a room temperature of 23 ° C. and a relative humidity of 50%. Next, in accordance with JIS Z 0237, the adhesive tape was peeled off at a speed of 300 mm / min, and the adhesive strength (180 ° peel strength) of the winding outer side sample and the core side sample was measured.
From the obtained data, the rate of change in adhesive strength (| adhesive force of core side sample-adhesive force of sample on outer side of winding | adhesive force of sample on outer side of winding x 100) was calculated.

(5) Contamination The adhesive tape of the winding outer side sample or the core side sample cut into a 25 mm width was attached to an acrylic resin plate with a thickness of 130 μm, and five samples of each were prepared. Each sample was left at 50 ° C. for 1 week. After standing, each sample was taken out to room temperature, and left for a further 60 minutes. Then, in accordance with JIS Z0237, the adhesive tape was peeled from the acrylic resin plate in a 180 ° direction at a tensile speed of 300 mm / min. About the acrylic resin board after adhesive tape exfoliation, the existence of the contamination of the surface was observed visually, and the contamination was judged on the following standards.
:: no contamination of the surface of the acrylic resin plate in each sample :: a sample partially contaminated by the generation of adhesive residue on the surface of the acrylic resin plate (1% or less of the entire area) ×: surface of the acrylic resin plate There is a sample (more than 1% of the total area) with contamination due to occurrence of adhesive residue

According to the present invention, it is possible to provide a pressure-sensitive adhesive tape roll and an optical film laminate which is light spreadable and which has little change in the adhesion of the pressure-sensitive adhesive tape regardless of the delivery position.

1 adhesive tape roll 2 adhesive tape 21 substrate layer 22 adhesive layer

Claims (11)

A pressure-sensitive adhesive tape roll obtained by winding a pressure-sensitive adhesive tape having a substrate layer and a pressure-sensitive adhesive layer in the form of a roll,
A pressure-sensitive adhesive tape roll, wherein the base material layer contains a release agent (a), and the pressure-sensitive adhesive layer contains a release agent (b). 2. The adhesive tape roll according to claim 1, wherein the adhesive force change ratio between the adhesive force of the winding core side sample and the adhesive force of the winding outer side sample is 50% or less. The pressure-sensitive adhesive tape roll according to claim 1 or 2, wherein the difference ΔSP1 of the SP value between the base resin constituting the base layer and the release agent (a) is 0.1 or more. 4. The pressure-sensitive adhesive tape roll according to claim 1, wherein the difference .DELTA.SP2 between the SP value of the base resin constituting the pressure-sensitive adhesive layer and the release agent (b) is 0.1 or more. The pressure-sensitive adhesive layer contains a tackifier, and the content of the tackifier in the pressure-sensitive adhesive layer is 40 parts by weight or less with respect to 100 parts by weight of the base resin constituting the pressure-sensitive adhesive layer. The pressure-sensitive adhesive tape roll according to claim 1, 2, 3 or 4 characterized in that. The releasing agents (a) and (b) are characterized in that they are amine-based releasing agents, silicone-based releasing agents, fluorine-based releasing agents, hydrocarbon-based releasing agents or metal soap-based releasing agents. The adhesive tape roll of Claim 1, 2, 3, 4 or 5. The adhesive tape roll according to claim 6, wherein the releasing agents (a) and (b) are amine releasing agents, and the amine releasing agents are fatty acid bisamides. The adhesive tape roll according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the base material layer contains a polyolefin resin, a polyester resin or an acrylic resin. The pressure-sensitive adhesive tape roll according to claim 1, 2, 3, 4, 5, 6, 7, or 8, wherein the pressure-sensitive adhesive layer contains a styrenic elastomer. The adhesive tape roll according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, wherein the winding length of the adhesive tape roll is 300 m or more. An optical film laminate in which an adhesive tape and an optical film are laminated,
The adhesive tape has a substrate layer and an adhesive layer,
The said base material layer contains a mold release agent (a), and the said adhesive layer contains a mold release agent (b), The optical film laminated body characterized by the above-mentioned.

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