JP2018203856A - Adhesive laminate - Google Patents

Abstract

To provide an adhesive laminate having both low temperature tackiness and high temperature holding strength.SOLUTION: An adhesive laminate of an embodiment of the disclosure includes a substrate and a pressure-sensitive adhesive layer arranged on the substrate. The pressure-sensitive adhesive layer contains a styrene-isoprene-styrene copolymer, a first tackifier having a softening point of 70°C or higher, and a second tackifier having a softening point of 50°C or lower. The pressure-sensitive adhesive layer contains the styrene-isoprene-styrene copolymer of 53 pts.mass or more relative to 100 pts.mass of the sum of the styrene-isoprene-styrene copolymer, the first tackifier, and the second tackifier, while containing the second tackifier of 0.5 pt.mass or more and 16 pts.mass or less relative to 100 pts.mass of the styrene-isoprene-styrene copolymer.SELECTED DRAWING: None

Description

  The present invention relates to an adhesive laminate.

  In agricultural applications, box sealing tape is widely used for the purpose of packing vegetables, fruits and the like in cardboard boxes. The box sealing tape includes a base material and a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is formed using a hot-melt pressure-sensitive adhesive composition.

  Patent Document 1 (Japanese Patent Application Laid-Open No. 11-106729) states that “in a hot melt pressure-sensitive adhesive composition containing a polystyrene-based thermoplastic elastomer and a tackifier resin, the viscosity average molecular weight is 5000 to 9000 as an adhesive property modifier. A hot melt pressure-sensitive adhesive composition comprising at least one liquid polymer selected from the group consisting of a liquid ethylene / propylene copolymer and a liquid ethylene / propylene / non-conjugated diene copolymer ”. ing.

JP-A-11-106729

  The box sealing tape is required to easily adhere to various types of cardboard boxes in a wide temperature range, for example, 0 ° C. to 50 ° C., and maintain the packaging state with a sufficient holding force. Cardboard boxes used for packaging vegetables, fruits, and the like may have a water-repellent surface such as wax, and it is relatively difficult to bond the box sealing tape to such a surface. In addition, the adhesive force may be reduced by moisture generated over time from such contents. In general, it is difficult to achieve both low temperature tack (initial tackiness) and high temperature retention. Low temperature tack can be improved by increasing the amount of tackifier and adding a softener such as process oil, but this reduces the cohesive strength of the pressure sensitive adhesive layer and reduces the high temperature retention.

  This indication provides the adhesion layered product which can be used for various uses including the above box sealing tapes, and can make low temperature tack and high temperature retention power compatible.

  According to one embodiment of the present disclosure, a pressure-sensitive adhesive laminate including a base material and a pressure-sensitive adhesive layer disposed on the base material, wherein the pressure-sensitive adhesive layer is a styrene-isoprene-styrene copolymer. A first tackifier having a softening point of 70 ° C. or higher, and a second tackifier having a softening point of 50 ° C. or lower, and the pressure-sensitive adhesive layer includes the styrene-isoprene-styrene copolymer as the styrene. -An isoprene-styrene copolymer, the first tackifier and the second tackifier are contained in an amount of 53 parts by mass or more with respect to 100 parts by mass in total, and the second tackifier is contained in the styrene-isoprene. -The adhesion laminated body is contained including the amount of 0.5 mass part or more and 16 mass parts or less with respect to 100 mass parts of styrene copolymers.

  The pressure-sensitive adhesive laminate of the present disclosure has both a low-temperature tack and a high-temperature holding force, and is suitable for, for example, a box sealing tape used for agricultural purposes and a decorative sheet used for indoor and outdoor decorative purposes. .

  The above description should not be regarded as disclosing all embodiments of the present invention and all advantages related to the present invention.

  Hereinafter, the present invention will be described in more detail for the purpose of illustrating representative embodiments of the present invention, but the present invention is not limited to these embodiments.

  It is understood by those skilled in the art that the characteristic values mentioned in the present disclosure (specifically, ball tack, rolling wheel tack, peeling force, and holding force) are equivalent to the methods described in the embodiments of the present disclosure, or equivalent thereto. It is a value measured by an understood method.

  The pressure-sensitive adhesive laminate according to one embodiment of the present disclosure includes a base material and a pressure-sensitive adhesive layer disposed on the base material. The pressure-sensitive adhesive layer includes a styrene-isoprene-styrene copolymer, a first tackifier having a softening point of 70 ° C. or higher, and a second tackifier having a softening point of 50 ° C. or lower. The amount of the styrene-isoprene-styrene copolymer is 53 parts by mass or more with respect to a total of 100 parts by mass of the styrene-isoprene-styrene copolymer, the first tackifier, and the second tackifier in the pressure-sensitive adhesive layer. Included. The second tackifier is included in the pressure-sensitive adhesive layer in an amount of 0.5 to 16 parts by mass with respect to 100 parts by mass of the styrene-isoprene-styrene copolymer. In addition, the softening point in this indication is based on the measurement by JISK2207 (2006 edition) ring and ball type.

  The substrate may be various materials and articles depending on the application, and examples thereof include paper, polymer film, metal plate, woven fabric, non-woven fabric, foam, decorative sheet, decorative plate, wallpaper, and flooring. The base material may be a laminate composed of a plurality of layers. The substrate may be a part of an article, for example, a part of a decorative sheet. The base material may have a surface treatment such as a primer treatment, a corona treatment, or a frame treatment on the bonding surface with the pressure-sensitive adhesive layer.

  For example, in an embodiment in which the pressure-sensitive adhesive laminate is a tape, a substrate containing a conventionally known material that can be used as a support for the tape can be used as a base material. For example, paper such as kraft paper, crepe paper, and Japanese paper , Films containing polymers such as polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), laminated paper, woven fabric, non-woven fabric, polymer foam, and the like. The polymer film may be uniaxially or biaxially stretched. In box sealing tape applications, biaxially oriented polypropylene (OPP) films are advantageously used in terms of strength, weather resistance and the like.

  The dimensions of the substrate can be variously set according to the form and use of the pressure-sensitive adhesive laminate. For example, in embodiments where the adhesive laminate is a tape, the width of the substrate can generally be about 9 mm or more, about 15 mm or more, or about 30 mm or more, about 150 mm or less, about 100 mm or less, or about 70 mm or less, The thickness can generally be about 10 μm or more, about 25 μm or more, or about 40 μm or more, about 500 μm or less, about 200 μm or less, or about 125 μm or less.

  The base material may have a peeling treatment on the surface (back surface) opposite to the surface on which the pressure-sensitive adhesive layer is disposed. In the embodiment in which the pressure-sensitive adhesive laminate is a tape, the substrate generally has a peeling treatment on the back surface, which makes it possible to smoothly draw out the tape in use. Examples of the release treatment include coating using a silicone-based, long-chain alkyl-based or fluorine-based release treatment agent.

  When the base material is an absorbent material such as paper, the barrier layer may be formed on the base material, and then a peeling treatment may be performed on the barrier layer. Examples of materials contained in the barrier layer include acrylic resins, polyesters, styrene-butadiene copolymers, styrene-butadiene-acrylonitrile resins, melamine resins, polyamides, and elastomers such as urea formaldehyde resins, polyamides (for example, nylon), and polyolefins. (For example, polypropylene, polyethylene), polystyrene, polyester, polyvinyl chloride, polyvinyl acetate, ethylene-propylene copolymer, polymethyl methacrylate, thermoplastic rubber block copolymer and other thermoplastic resins, and blends and mixtures thereof. Can be mentioned.

  The pressure sensitive adhesive layer includes a styrene-isoprene-styrene (SIS) copolymer as a tacky polymer. Styrene-isoprene-styrene copolymer is a block copolymer having a hard segment and a soft segment, and can be applied with tack, agglomeration, and coatability (for example, with a substantially uniform thickness when producing a laminate). ), Excellent in workability.

  The styrene-isoprene-styrene copolymer is 53 parts by mass or more in the pressure-sensitive adhesive layer with respect to 100 parts by mass in total of the styrene-isoprene-styrene copolymer, the first tackifier, and the second tackifier. Included in quantity. In some embodiments, the styrene-isoprene-styrene copolymer is pressure sensitive adhesive to a total of 100 parts by weight of the styrene-isoprene-styrene copolymer, the first tackifier, and the second tackifier. The layer is included in an amount of about 55 parts by weight or more or about 58 parts by weight or more, about 70 parts by weight or less, or about 65 parts by weight or less. When the amount of the styrene-isoprene-styrene copolymer is within the above range, it is possible to provide the pressure-sensitive adhesive layer with adhesive properties excellent in the balance between the low temperature tack and the high temperature holding power.

  The amount of styrene in the styrene-isoprene-styrene copolymer is generally about 10% or more, about 12% or more, or about 14% or more, about 30% or less, about 25% or less, or about 20% or less. A styrene-isoprene-styrene copolymer having a styrene content in the above range is excellent in the balance between high temperature holding power, tack, and processability. For example, the cohesive force of the pressure-sensitive adhesive layer itself and the wet spreadability at the initial stage of adhesion can be maintained in a balanced manner. Further, the styrene-isoprene-styrene copolymer raw material can be conveyed to an inlet such as a hopper in the form of pellets.

  The diblock amount of the styrene-isoprene-styrene copolymer is generally about 5% or more, about 8% or more, or about 10% or more, about 50% or less, about 45% or less, or about 40% or less. A styrene-isoprene-styrene copolymer having a diblock amount in the above range is excellent in the balance between high temperature holding power and tack. For example, the cohesive force of the pressure-sensitive adhesive layer itself and the wet spreadability at the initial stage of adhesion can be maintained in a balanced manner.

  The weight average molecular weight (Mw) of the styrene-isoprene-styrene copolymer is generally about 30,000 or more, about 50,000 or more or about 70,000 or more, about 1 million or less, about 500,000 or less, or about 300,000 or less.

  The 300% modulus of the styrene-isoprene-styrene copolymer is generally about 0.3 MPa or more, about 0.5 MPa or more, or about 0.7 MPa or more, about 3.0 MPa or less when measured according to JIS K 6251. , About 2.5 MPa or less or about 2.0 MPa or less. A styrene-isoprene-styrene copolymer having a 300% modulus in the above range is excellent in the balance between high-temperature holding power, tack, and coatability.

  As a styrene-isoprene-styrene copolymer, for example, Quintac (trademark) (Nippon Zeon Co., Ltd.), Kraton (trademark) D SIS polymer (Clayton Polymer Japan Co., Ltd.) and the like can be used.

  The pressure-sensitive adhesive layer is an olefin-based elastomer such as ethylene-vinyl acetate copolymer, ethylene-α-olefin copolymer, polyethylene, and polypropylene, in addition to the styrene-isoprene-styrene copolymer, as long as the adhesive properties are not impaired. For example, about 20% by mass or less, about 15% by mass or less, or about 10% by mass or less of the total polymer in the pressure-sensitive adhesive layer may be the olefin-based elastomer. In one embodiment, the pressure sensitive adhesive layer does not include a tacky polymer other than a styrene-isoprene-styrene copolymer.

  As the first tackifier, various tackifiers having a softening point of 70 ° C. or higher can be used. By using a tackifier having a softening point of 70 ° C. or higher as a first tackifier in combination with a second tackifier having a softening point of 50 ° C. or lower, a high temperature holding force can be obtained without impairing low temperature tack. Can be maintained. Examples of such tackifiers include aliphatic petroleum resins, alicyclic petroleum resins, aromatic petroleum resins, rosin resins, terpene resins, styrene resins, phenolic resins, coumarone-indene resins, and the like. And derivatives thereof. A 1st tackifier can be used individually or in combination of 2 or more types. Since the compatibility with the styrene-isoprene-styrene copolymer is good, it is advantageous to use an aliphatic petroleum resin as the first tackifier.

  In some embodiments, the softening point of the first tackifier is about 80 ° C or higher, or about 90 ° C or higher, about 130 ° C or lower, or about 120 ° C or lower.

  The amount of the first tackifier is generally about 30 parts by mass or more or about 50 parts by mass or more, about 150 parts by mass or less or about 120 parts by mass or less with respect to 100 parts by mass of the styrene-isoprene-styrene copolymer. . By setting the amount of the first tackifier in the above range, both tack and cohesive force can be obtained in a balanced manner.

  As the second tackifier, various tackifiers having a softening point of 50 ° C. or less can be used. The second tackifier is included in the pressure-sensitive adhesive layer in an amount of 0.5 to 16 parts by mass with respect to 100 parts by mass of the styrene-isoprene-styrene copolymer. When the pressure-sensitive adhesive layer contains the predetermined amount of the second tackifier, the low-temperature tack can be applied to the pressure-sensitive adhesive layer without impairing the high-temperature holding power. Examples of such tackifiers include aliphatic petroleum resins, alicyclic petroleum resins, aromatic petroleum resins, rosin resins, terpene resins, terpene phenol resins, styrene resins, phenol resins, coumarone-indenes. Examples thereof include resins and derivatives thereof. A 2nd tackifier can be used individually or in combination of 2 or more types. In some embodiments, the second tackifier is a compound containing an alicyclic structure, and specifically includes alicyclic petroleum resins, terpene resins, terpene phenol resins, and the like. The second tackifier is desirably a terpene phenol resin. In this regard, although not limited by any theory, it is considered that the phenolic hydroxyl group contained in the terpene phenol resin contributes particularly advantageously to the maintenance of the cohesive force of the pressure-sensitive adhesive layer.

  In some embodiments, the softening point of the second tackifier is about 10 ° C or higher, or about 20 ° C or higher, about 40 ° C or lower, or about 35 ° C or lower.

  In some embodiments, the amount of the second tackifier is about 1 part by weight or more or about 1.5 parts by weight or more and about 15 parts by weight or less based on 100 parts by weight of the styrene-isoprene-styrene copolymer. Or about 12 mass parts or less.

  In one embodiment, the pressure sensitive adhesive layer does not include a process oil. Process oil is known as a softening agent for hot melt pressure-sensitive adhesive compositions, and examples thereof include naphthenic oils, aromatic oils, and paraffinic oils. Since the pressure-sensitive adhesive layer does not contain process oil, the high temperature holding force can be increased.

  The pressure-sensitive adhesive layer may contain additives such as an antioxidant, a heat stabilizer, an ultraviolet absorber, and a filler as needed as long as the adhesive properties are not impaired.

  The pressure-sensitive adhesive laminate comprises a pressure-sensitive adhesive composition containing a styrene-isoprene-styrene copolymer, a first tackifier, a second tackifier, and, if necessary, an additive on a substrate using a hot melt coater or the like. It is possible to manufacture by forming a pressure-sensitive adhesive layer on the substrate. The pressure-sensitive adhesive laminate is formed by applying the pressure-sensitive adhesive composition onto a liner that has been subjected to a release treatment as necessary to form a pressure-sensitive adhesive layer, and then transferring the pressure-sensitive adhesive layer onto the substrate by thermal lamination or the like. Can also be manufactured. The pressure-sensitive adhesive composition may be a solvent system, an aqueous system such as an emulsion, or a solventless system.

  The adhesive composition has a melt viscosity at 190 ° C. of about 1,000 mPa · s or more, about 2,000 mPa · s or more, about 500,000 mPa · s or less, or about 400,000 mPa · s from the viewpoint of coating properties. Advantageously, it is s or less.

  The thickness of the pressure sensitive adhesive layer is generally about 5 μm or more, about 10 μm or more, or about 15 μm or more, about 100 μm or less, about 80 μm or less, or about 50 μm or less. Increasing the thickness of the pressure-sensitive adhesive layer can increase the low temperature tack and the high temperature holding force, but it is disadvantageous in terms of cost. In some embodiments, from a cost standpoint, the thickness of the pressure sensitive adhesive layer is reduced as long as the desired adhesive properties are obtained, for example, the thickness of the pressure sensitive adhesive layer is about 40 μm or less or about 30 μm or less.

  The pressure-sensitive adhesive laminate may include a liner on the pressure-sensitive adhesive layer. Examples of the liner include plastic materials such as polyethylene, polypropylene, polyester, and cellulose acetate, paper, and paper coated with the plastic material. These liners may have a surface subjected to a release treatment with silicone, a fluororesin, a long-chain alkyl resin, or the like.

  In one embodiment, the ball tack of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive laminate is 4 or more, 5 or more, or 6 or more when measured at 5 ° C. according to JIS Z 0237 (2000 edition).

  In one embodiment, the holding power of the pressure-sensitive adhesive layer to the water-repellent treated surface of the pressure-sensitive adhesive laminate is about 100 minutes or more when measured at 40 ° C. under a load of 1 kg according to JIS Z 0237 (2000 edition). 500 minutes or more, or about 1000 minutes or more.

  The pressure-sensitive adhesive laminate may be in the form of a tape (roll shape) or in the form of a sheet.

  The pressure-sensitive adhesive laminate of the present disclosure has a low temperature tack and a high temperature holding force in an excellent balance. The pressure-sensitive adhesive laminate of the present disclosure can be used as, for example, a box sealing tape applied to a water-repellent cardboard box for agricultural use, an indoor / outdoor advertisement, a decorative sheet used for decoration, and the like.

  In the following examples, embodiments of the present disclosure will be described more specifically, but the scope of the present invention is not limited thereto.

  The materials used in this example are shown in Table 1.

<Examples 1-7 and Comparative Examples 1-5>
The pressure-sensitive adhesive composition containing each component in the formulation shown in Table 2 was applied onto a biaxially oriented polypropylene (OPP) film having a thickness of 40 μm using extrusion hot melt coating, and having a thickness of 40 μm on the OPP film. By forming a pressure-sensitive adhesive layer, pressure-sensitive adhesive laminates of Examples 1 to 7 and Comparative Examples 1 to 5 were produced. M100 / 1076 is a mixture of 98% by weight Quintone ™ M100 and 2% by weight Irganox ™ 1076.

<Example 8 and Comparative Example 6>
The pressure-sensitive adhesive composition containing each component with the formulation shown in Table 3 was applied on a biaxially oriented polypropylene (OPP) film having a thickness of 40 μm to a thickness of about 24 μm using extrusion hot melt coating. The pressure-sensitive adhesive layers of Example 8 and Comparative Example 6 were produced by forming a pressure-sensitive adhesive layer on the OPP film.

<Comparative Example 7>
As the adhesive laminate of Comparative Example 7, the carton tape No. 640-PF (natural rubber adhesive, Nichiban Co., Ltd.) was used.

  The characteristics of the adhesive laminate were evaluated by the following procedure.

<Peeling force>
The adherend is stainless steel or water-repellent cardboard. In accordance with JIS Z 0237 (2000 version), 180 degree peeling is measured at a test temperature of 23 ° C. and a relative humidity of 50%.

<Ball tack>
According to JIS Z 0237 (2000 version), ball tack is measured at a slope angle of 20 degrees, a temperature of 5 ± 1 ° C., 10 ± 1 ° C., or 23 ± 1 ° C.

<Rolling wheel tack test>
The test is performed in a room of 5 ± 1 ° C., 10 ± 1 ° C., or 23 ± 1 ° C. The sample and tester are used after being left indoors for 10 minutes or longer. Adhere double-sided tape to the back of the sample, and stick double-sided tape at the position where the sample of the rolling wheel tack tester is to be stuck so that air bubbles do not enter. The rolling wheel is wiped with methyl ethyl ketone (MEK), then wiped with hexane, and set on a testing machine. Raise the stopper slowly and roll the wheel to mark the position where the wheel stopped. While holding the wheel by hand, move the wheel slowly to mark the position where the wheel and sample first contact. Measure the distance between the two marked points. The shorter the distance, the greater the tack.

<Retention force>
The holding force is measured according to JIS Z 0237 (2000 edition). The adherend is stainless steel or water-repellent cardboard. The tape dimension is 25 mm × 25 mm. The sample is applied to the adherend using a 700 g roller. The test load is 1 kg or 2 kg. The test temperature is 23 ° C or 40 ° C.

  The evaluation results are shown in Tables 2 and 3.

  The pressure-sensitive adhesive laminate of the present disclosure is suitable for, for example, a box sealing tape used for agricultural purposes, a decorative sheet used for indoor and outdoor decorative purposes, and the like.

Claims (6)

A pressure-sensitive adhesive laminate comprising a base material and a pressure-sensitive adhesive layer disposed on the base material,
The pressure-sensitive adhesive layer includes a styrene-isoprene-styrene copolymer, a first tackifier having a softening point of 70 ° C or higher, and a second tackifier having a softening point of 50 ° C or lower, and the pressure-sensitive adhesive layer The amount of the styrene-isoprene-styrene copolymer is 53 parts by mass or more with respect to a total of 100 parts by mass of the styrene-isoprene-styrene copolymer, the first tackifier, and the second tackifier. And the second tackifier is contained in an amount of 0.5 parts by mass or more and 16 parts by mass or less with respect to 100 parts by mass of the styrene-isoprene-styrene copolymer.   The pressure-sensitive adhesive laminate according to claim 1, wherein the second tackifier is a terpene phenol resin.   The pressure-sensitive adhesive laminate according to claim 1 or 2, wherein the first tackifier is an aliphatic petroleum resin.   The pressure-sensitive adhesive laminate according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer does not contain process oil.   The pressure-sensitive adhesive laminate according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive laminate is a tape.   The pressure-sensitive adhesive laminate according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive laminate is a sheet.