JP2014019858A - Resin film for adhesive sheet substrate and pressure sensitive adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin film for an adhesive sheet substrate, capable of reducing malfunction due to migration of a low molecular weight component to an adhesive layer, while maintaining a flexibility.SOLUTION: A resin film for an adhesive sheet substrate includes an olefinic thermoplastic elastomer including propylene and ethylene and/or α-olefin having 4-8 carbon atoms as polymerization components. In the olefinic thermoplastic elastomer, an elution portion at 0°C is 10 wt.% or smaller with regard to a whole elution amount, in temperature-rise elution fractionation within a range of 0-140°C when o-dichlorobenzene is used as a solvent.

Description

  The present invention relates to a resin film for a pressure-sensitive adhesive sheet base material, and more particularly relates to a resin film for a pressure-sensitive adhesive sheet base material that is flexible and can reduce adverse effects on a pressure-sensitive adhesive, and a pressure-sensitive adhesive sheet using the same.

  A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer provided on a flexible resin film is excellent in followability and expandability, and is therefore used for applications such as labels and dicing tape.

  For example, in the following Patent Document 1, an adhesive layer is provided on at least one surface of a base film, and the base film is composed of propylene and ethylene and / or an α-olefin having 4 to 8 carbon atoms as a polymerization component. A dicing pressure-sensitive adhesive sheet containing an olefin-based thermoplastic elastomer containing and having a melting peak temperature of 120 ° C. or higher is disclosed.

  Patent Document 2 listed below includes a layer composed of a linear low density polyethylene having a density of 0.910 to 0.935, a specific melting point, a weight average molecular weight (Mw), and a certain range determined by a cross fractionation method. An adhesive tape base material in which layers made of a polypropylene resin composition having a composition are laminated is disclosed.

Japanese Patent Laid-Open No. 2003-7654 JP 2005-297247 A

Olefin-based thermoplastic elastomers used as materials for flexible resin films such as such adhesive tape base materials generally contain a large amount of low molecular weight components, thereby often exhibiting a flexibility effect.
For example, in the olefinic thermoplastic elastomer disclosed in Patent Document 1, the amount eluted at 0 ° C. in the temperature rising elution fractionation between 0 ° C. and 140 ° C. using o-dichlorobenzene as a solvent is the total elution amount. On the other hand, it is 10 to 60% by weight, and when the proportion of elution at 0 ° C. is reduced, the base film obtained by molding the olefinic thermoplastic elastomer is hard, and the extensibility during expansion is deteriorated. The pickups also tend to be difficult.

  Moreover, in patent document 2, it is said that it is lacking in a softness | flexibility that the resin elution amount of 0 degreeC or more and 10 degrees C or less in a polypropylene resin composition is below a specific range.

  However, although there are many low molecular weight components, the effect of flexibility is good, but when these components migrate to the adhesive layer, the cohesive strength of the adhesive is reduced, resulting in a decrease in adhesive strength, release paper, and target for pasting. It was found that problems such as the occurrence of adhesive residue on the surface occurred.

  The present invention seeks to solve the problems associated with the prior art as described above, and reduces the inconvenience due to the migration of low molecular weight components to the pressure-sensitive adhesive layer while maintaining flexibility. Is to provide.

This invention is the following resin films for adhesive sheet base materials.
(1) An olefinic thermoplastic elastomer containing propylene and ethylene and / or an α-olefin having 4 to 8 carbon atoms as a polymerization component is contained, and the olefinic thermoplastic elastomer uses o-dichlorobenzene as a solvent. A resin film for a pressure-sensitive adhesive sheet substrate, wherein the elution fraction at 0 ° C. in the temperature rising elution fractionation between the temperatures used is 0 to 140 ° C. is less than 10% by weight with respect to the total elution amount.
(2) The olefinic thermoplastic elastomer is an ethylene / propylene copolymer block having a hard segment polymerized using a metallocene catalyst, and is an olefinic thermoplastic elastomer obtained by multistage polymerization. (1) The resin film for adhesive sheet base materials of description.
(3) The olefinic thermoplastic elastomer has an elution fraction at 0 ° C. to 10 ° C. of 30% of the total elution amount in the temperature rising elution fractionation between 0 ° C. and 140 ° C. using o-dichlorobenzene as a solvent. The resin film for pressure-sensitive adhesive sheet substrates according to (1) or (2), which is less than% by weight.
(4) The olefinic thermoplastic elastomer has an elution fraction at 0 ° C. to 20 ° C. in a temperature rising elution fraction between 0 ° C. and 140 ° C. using o-dichlorobenzene as a solvent with respect to the total elution amount. The resin film for pressure-sensitive adhesive sheet base materials according to any one of (1) to (3), which is less than% by weight.
(5) The olefinic thermoplastic elastomer has an elution fraction at 0 ° C. to 30 ° C. in the temperature rising elution fractionation between 0 ° C. and 140 ° C. using o-dichlorobenzene as a solvent with respect to the total elution amount. The resin film for pressure-sensitive adhesive sheet base materials according to any one of (1) to (4), which is less than% by weight.
(6) The resin film for an adhesive sheet substrate according to any one of (1) to (5), wherein the olefinic thermoplastic elastomer is contained in an amount of 70% by weight or more.
(7) The resin film for adhesive sheet base materials according to any one of (1) to (6), wherein the tensile elastic modulus is 400 MPa or less.
(8) The resin film for a pressure-sensitive adhesive sheet substrate according to any one of (1) to (7), wherein the haze is 15% or less.

Moreover, this invention is the following adhesive sheets.
(9) A pressure-sensitive adhesive sheet obtained by laminating a pressure-sensitive adhesive layer on the resin film for a pressure-sensitive adhesive sheet substrate according to (1) to (8).

  According to the present invention, it is possible to provide a resin film for a pressure-sensitive adhesive sheet substrate that is excellent in sufficient flexibility, mechanical strength, and transparency, while reducing problems due to migration of a low molecular weight component to the pressure-sensitive adhesive layer. I can do it.

[Olefinic thermoplastic elastomer]
The olefinic thermoplastic elastomer used in the present invention is not particularly limited as long as it is an olefinic thermoplastic elastomer containing propylene and ethylene and / or an α-olefin having 4 to 8 carbon atoms as a polymerization component. For example, isoprene Diene rubbers (elastomers) such as rubber, butadiene rubber, butyl rubber, propylene-butadiene rubber, acrylonitrile-butadiene rubber and acrylonitrile-isoprene rubber, ethylene-propylene copolymer rubber, ethylene-propylene non-conjugated diene rubber, ethylene-butadiene copolymer Combined rubber, low crystalline propylene homopolymer having a crystal melting heat (ΔH) of 100 g / J or less, polyolefin obtained by a multistage polymerization method, rubber (component) and polyethylene resin and / or polypropylene Examples thereof include polyolefins obtained by dynamically crosslinking a mixture with a pyrene resin.

  The crystal melting heat (ΔH) is a value calculated from the melting peak area when dissolved at a rate of 10 ° C./min using a differential scanning calorimeter (DSC). The polyolefin obtained by a legal method is a copolymer obtained by multistage polymerization of (i) hard segment and (ii) soft segment in two or more stages in a reactor. (I) As a hard segment, a propylene homopolymer block or a copolymer block of propylene and an α-olefin, for example, binary such as propylene / ethylene, propylene / 1-butene, propylene / ethylene / 1-butene Or a terpolymer block is mentioned. In addition, (ii) as a soft segment, an ethylene homopolymer block or a copolymer block of ethylene and α-olefin, such as ethylene / propylene, ethylene / 1-butene, ethylene / propylene / 1-butene, etc. Examples include binary or ternary copolymer blocks.

[Elution]
In the present invention, the olefinic thermoplastic elastomer has an elution fraction at 0 ° C. in the temperature rising elution fractionation between 0 ° C. and 140 ° C. using o-dichlorobenzene as a solvent of 10% by weight with respect to the total elution amount. It is important to be less than%. More preferably, it is less than 8 weight%, Most preferably, it is less than 6 weight%.
If the elution amount at 0 ° C. is less than 10% by weight with respect to the total elution amount, it is possible to suppress the decrease in the adhesive force generated by the migration of the low molecular weight component from the base material layer to the adhesive layer. Furthermore, it is possible to prevent the cohesive force of the pressure-sensitive adhesive from being lowered due to the migration of the low molecular weight component, and it is possible to suppress problems such as the occurrence of adhesive residue on the release paper and the pasting target.

Furthermore, it is preferable that the amount of elution at 0 ° C. to 10 ° C. is less than 30% by weight. More preferably, it is less than 20% by weight, particularly preferably 10% by weight.
Moreover, it is preferable that the elution part in 0 to 20 degreeC is less than 35 weight%. More preferably, it is less than 30% by weight, particularly preferably 20% by weight.
Moreover, it is preferable that the elution part in 0 to 30 degreeC is less than 40 weight%. More preferably, it is less than 35% by weight, particularly preferably 30% by weight.
Not only 0 ° C., but also the amount of elution in the vicinity of room temperature is within the above range, thereby making it possible to more effectively prevent a decrease in the adhesive force over time, and to produce a more practical resin film for a pressure-sensitive adhesive sheet substrate. Can be obtained.

As the olefin thermoplastic elastomer having a small amount of elution, an ethylene / propylene copolymer block in which the hard segment is polymerized using a metallocene catalyst is particularly preferable.
According to this, since it is excellent also in a softness | flexibility and transparency, the protective tape with a visual inspection in the state which stuck the adhesive sheet, the repair tape for transparent materials, such as glass, etc. can be provided.

[Other ingredients]
The resin film for a pressure-sensitive adhesive sheet substrate of the present invention can contain other resins and various additives as necessary in addition to the olefin-based thermoplastic elastomer. Examples of such resins include polyolefins such as polypropylene and polyethylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyvinyl chloride, polyurethane, polyamide, ethylene / vinyl alcohol copolymer, olefin elastomer, and styrene elastomer. It is done. Moreover, as an additive, a heat stabilizer, antioxidant, a ultraviolet absorber, a lubricant, an antiblocking agent, a coloring agent etc. are mentioned, for example.

  It is preferable that content of the said olefin type thermoplastic elastomer in the resin film for adhesive sheet base materials of this invention is 70 weight% or more. More preferably, it is 80 weight% or more. By making the content of the olefinic thermoplastic elastomer 70% by weight or more, it is possible to design a film that takes advantage of the excellent characteristics of the olefinic thermoplastic elastomer, and for adhesive sheet substrates that are advantageous in terms of flexibility and transparency It can be set as a resin film.

[Layer structure of substrate]
The resin film for an adhesive sheet substrate of the present invention may be a single layer film or a multilayer film.
In the case of a multilayer film, it is sufficient that at least one layer uses 70% by weight or more of the olefin-based thermoplastic elastomer, and two types and two layers of laminated films composed of front and back layers and / or 2 composed of front and back layers and an intermediate layer. It can also be set as a seed 3 layer laminated film.

[Film thickness]
In the preferable aspect of this invention, the thickness of this resin sheet for adhesive sheet base materials is 0.03-0.5 mm, More preferably, it is 0.05-0.3 mm. If it is the range of said specific value, while maintaining a softness | flexibility, sufficient intensity | strength as an adhesive sheet is maintained, and it is excellent also in moldability.

[Tensile modulus]
In the preferable aspect of this invention, the tensile elasticity modulus of this resin film for adhesive sheet base materials is 400 Mpa or less. More preferably, it is 350 MPa or less.
If the tensile modulus is 400 MPa or less, it can be suitably used for various applications that require flexibility. For example, when used as a base material for dicing tape, a tape having good extensibility upon expansion can be obtained, and when used as a base material for labels, a label having good followability to uneven surfaces can be obtained. Can do.

[Haze]
In the preferable aspect of this invention, the haze value of the resin composition which comprises this resin film for adhesive sheet base materials is 15% or less. More preferably, it is 10% or less.
If the haze value is 15% or less, it can be used for various applications that require transparency. For example, when used as a substrate for a dicing tape, a tape having a high transparency of the irradiated radiation can be obtained to cure the radiation-curable adhesive, and when used as a substrate for a label, It is possible to obtain a label that does not impair the design and visibility of the body.

[Manufacturing method of substrate]
In the process of producing the base film, a general polyolefin-based resin film molding method such as an extrusion molding method such as a T-die extrusion molding method, an inflation molding method, or a calendar molding method is used. An extrusion machine is suitable. The melt flow rate of the resin composition at the time of extrusion is 1 to 20 g / 10 minutes, preferably 5 to 15 g / 10 minutes. If the melt flow rate of the resin composition is 1 g / 10 min or more, the melt viscosity will not be too high and the extrusion processability will be good, and if it is 20 g / 10 min or less, the melt viscosity will not be too low. This is because the fluidity is good and the processability is excellent.

[Adhesive layer]
The pressure-sensitive adhesive sheet of the present invention only needs to contain at least one monolayer or multilayer film obtained in the present invention, and the pressure-sensitive adhesive used as the pressure-sensitive adhesive layer is not particularly limited. For example, natural rubber-based resin, acrylic Various pressure-sensitive adhesives such as resin, styrene resin, silicone resin, and polyvinyl ether resin are used.

  At least one side of the base film may be surface-treated by a method such as plasma treatment, corona treatment, ozone treatment, or flame treatment. Moreover, you may provide a primer layer between a base film and an adhesion layer if needed. Moreover, as long as the object of the present invention is not impaired, a resin layer may be further provided on the opposite surface of the pressure-sensitive adhesive sheet on the side where the pressure-sensitive adhesive layer is provided.

[Usage]
Although the adhesive sheet of this invention is not specifically limited as a use, For example, it is used suitably for a dicing tape, a label, a masking tape, a surface protection tape, a medical tape, a repair tape, a building material for interior and exterior.

  Embodiments of the present invention will be described in detail below with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

<Example 1>
Olefin-based thermoplastic elastomer A (Olefin-based thermoplastic elastomer “Wellnex RFG4VA” manufactured by Nippon Polypro Co., Ltd.) is introduced into the hopper of a single-screw extruder (50φ mm, L / D = 32) manufactured by Toshiba Machine, and the extruder temperature is set to C1. : 210 ° C, C2: 230 ° C, C3: 230 ° C, C4: 230 ° C, C5: 230 ° C, and extruded from a 550 mm wide T-die (temperature setting: 230 ° C, lip opening 0.3 mm) . The extruded molten resin was cooled and solidified with a winder (cooling roll 700 mm width × φ350 mm, roll temperature 30 ° C.) equipped with a cooling roll to obtain a base film.

<Example 2>
The olefinic thermoplastic elastomer A used in Example 1 and random polypropylene (Random Polypropylene “Novatech FX3B” manufactured by Nippon Polypro Co., Ltd.) were dry blended at a ratio of the former: latter (weight ratio) of 80:20. A film was formed under the conditions to obtain a base film.

<Example 3>
The olefinic thermoplastic elastomer A used in Example 1 and random polypropylene (Random polypropylene “Novatech FX3B” manufactured by Nippon Polypro Co., Ltd.) were dry blended at a ratio of the former: latter (weight ratio) 60:40, and the same as in Example 1. A film was formed under the conditions to obtain a base film.

<Comparative Example 1>
An olefin-based thermoplastic elastomer B (olefin-based thermoplastic elastomer “Cataloy C200F” manufactured by Sun Allomer Co., Ltd.) was formed under the same conditions as in Example 1 to obtain a base film.

  About each obtained film, the following evaluation items were evaluated.

<Evaluation of adhesive strength over time>
In order to evaluate the decrease in adhesive strength due to the migration of the low molecular weight component to the adhesive, a peel test was performed as follows according to JIS Z 0237. Test specimens (dimensions: length 300 mm, width 24 mm) are collected from the prepared film, and are applied to a SUS304 steel plate (dimensions: length 125 mm, width 50 mm, thickness 2 mm) using a double-sided adhesive tape (Nitto Denko No. 500). Bonding was performed using a 2 kg heavy roller. The test specimens obtained by heating and curing the bonded specimens in a gear oven manufactured by Toyo Seiki for one week and the specimens not subjected to thermal curing are respectively autographs (strips) made by Shimadzu under an atmosphere of 23 ° C. and 60% RH. The adhesive strength was measured by peeling 180 ° at a speed of 5 mm / min.
Evaluation was carried out according to the following criteria. Δ is within the practical range.
◎: Adhesive strength after 1 week curing is 160% or more ○: Adhesive strength after 1 week curing is less than 160% and 150% or more Δ: Adhesive strength after 1 week curing is less than 150% and 140% or more ×: 1 Table 2 shows the measurement results of less than 140% adhesive strength after weekly curing.

<Flexibility>
In order to evaluate the flexibility, in accordance with JIS K 7127, a test piece (No. 1 dumbbell) collected from the film was pulled with an autograph (pulling speed: 50 mm / min) manufactured by Shimadzu Corporation in an atmosphere of 23 ° C. and 60% RH. The elastic modulus was measured.
Evaluation was carried out according to the following criteria. Δ is within the practical range.
A: Tensile elastic modulus is 350 or less. O: Tensile elastic modulus is greater than 350 and 400 or less. Δ: Tensile elastic modulus is greater than 400 and 450 or less. X: Tensile modulus is greater than 450. Table 2 shows the measurement results.

<Transparency>
In order to evaluate transparency, the haze of the test piece collected from the film was measured according to JIS K 7105.
Evaluation was carried out according to the following criteria. Δ is within the practical range.
A: Haze value is 10% or less B: Haze value is greater than 10% and 15% or less Δ: Haze value is greater than 15% and 20% or less X: Haze value is greater than 20% Table 2 shows the measurement results.

In addition, the measurement conditions of temperature rising elution fractionation of the olefinic thermoplastic elastomer used for each Example are as follows.
<Measurement of temperature rise elution fraction>
Measuring apparatus: Cross fractionation chromatograph CFC2 (manufactured by Polymer ChAR), detector: infrared spectrophotometer IR4 (manufactured by Polymer ChAR), detection wavelength: 3.42 μm, GPC column: Shodex HT-806M (manufactured by Showa Denko KK) ), Column temperature: 140 ° C., column calibration: monodisperse polystyrene (manufactured by Tosoh Corporation), molecular weight calibration method: polystyrene conversion, eluent: o-dichlorobenzene (ODCB)
Flow rate: 1.0 mL / min, sample concentration: 90 mg / 30 mL (3 mg / mL), injection volume: 0.5 mL, temperature drop condition: 1 ° C./min (140 → 0 ° C.), then hold for 60 min, elution category: 0 10, 20, 30, 40, 50, 60, 70, 75, 80, 83, 86, 90, 94, 98, 102, 106, 110, 120, 140 ° C
The measurement results are shown in Table 1.

From Table 2, it is recognized that the resin films for adhesive sheet base materials of Examples 1 to 3 have little decrease in adhesive strength over time and further retain sufficient flexibility.
In particular, Examples 1 and 2 were superior to Example 3 in terms of flexibility and transparency, and were particularly preferred embodiments.

Claims (9)

  It comprises an olefinic thermoplastic elastomer containing propylene and ethylene and / or an α-olefin having 4 to 8 carbon atoms as a polymerization component, and the olefinic thermoplastic elastomer is a temperature using o-dichlorobenzene as a solvent. A resin film for a pressure-sensitive adhesive sheet substrate, wherein the elution at 0 ° C. in the temperature rising elution fractionation between 0 ° C. and 140 ° C. is less than 10% by weight based on the total elution amount.   2. The olefinic thermoplastic elastomer according to claim 1, wherein the hard segment part is an ethylene / propylene copolymer block polymerized using a metallocene catalyst, and is an olefinic thermoplastic elastomer obtained by multistage polymerization. Resin film for adhesive sheet base material.   The olefinic thermoplastic elastomer has an elution fraction at 0 ° C. to 10 ° C. of less than 30% by weight with respect to the total elution amount in the temperature rising elution fractionation between 0 ° C. and 140 ° C. using o-dichlorobenzene as a solvent. The resin film for pressure-sensitive adhesive sheet substrates according to claim 1 or 2.   The olefinic thermoplastic elastomer has an elution fraction at 0 ° C. to 20 ° C. of less than 35% by weight based on the total elution amount in the temperature rising elution fractionation between 0 ° C. and 140 ° C. using o-dichlorobenzene as a solvent. The resin film for adhesive sheet base materials of any one of Claims 1-3 which are these.   The olefin-based thermoplastic elastomer has an elution fraction at 0 ° C. to 30 ° C. of less than 40% by weight based on the total elution amount in the temperature rising elution fractionation between 0 ° C. and 140 ° C. using o-dichlorobenzene as a solvent. The resin film for adhesive sheet base materials according to any one of claims 1 to 4, wherein   The pressure-sensitive adhesive sheet substrate resin film according to any one of claims 1 to 5, comprising 70% by weight or more of the olefinic thermoplastic elastomer.   The tensile elasticity modulus is 400 Mpa or less, The resin film for adhesive sheet base materials of any one of Claims 1-6.   8. The resin film for a pressure-sensitive adhesive sheet substrate according to claim 1, having a haze of 15% or less.   The adhesive sheet formed by laminating | stacking an adhesive layer on the resin film for adhesive sheet base materials of Claims 1-8.