JPH0136877B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to an adhesive tape or sheet having a release layer. More specifically, to provide an adhesive tape or sheet that has excellent unwinding properties even when wound into a roll, allows the tape (sheet) to be stacked, has a peeling layer that has good magic ink writing properties, and has non-slip properties. It is. [Prior art] Many adhesive tapes or sheets are known, which are formed by providing a pressure-sensitive adhesive layer on one side of a support and winding it into a roll, and are widely used for applications such as packaging, bonding, and surface protection. . Adhesive tapes or sheets that are usually wound into a roll are
The back side has been peeled off. Silicone resins are known as typical release agents. In this case, there are problems such as migration of silicone to the surface of the pressure-sensitive adhesive layer, inability to overlay tapes (sheets), poor writing performance with magic ink, and slipperiness. In order to solve this problem, fatty acid amide is blended into at least one of the support or the pressure-sensitive adhesive layer in the adhesive tape or sheet,
Shear modulus is 2.0× ¹⁰⁸ dynes/ ^cm2 or less (JIS K-
7213), a method is known in which the main component of the release layer is an ethylene-α olefin copolymer whose surface wetting property is an equilibrium contact angle of 55° or more (JIS K-6768). However, although this type of adhesive tape or sheet has excellent unwinding properties when the main component of the pressure-sensitive adhesive layer is acrylic ester, The reality is that pressure adhesives do not have good rewinding properties. This is because pressure-sensitive adhesives mainly composed of natural and/or synthetic rubber are generally softer and more fluid than acrylic adhesives, and have a larger bonding area, resulting in a greater unwinding force. On the other hand, acrylic pressure-sensitive adhesives have problems such as poor initial resistance at low temperatures and high cost, which limits the types of tapes or sheets that can be used. [Problems to be Solved by the Invention] The purpose of the present invention is to solve the problem even when the pressure-sensitive adhesive layer is mainly composed of natural and/or synthetic rubber.
An object of the present invention is to provide an adhesive tape or sheet that can be wound into a roll and has excellent unwinding properties. Another object of the present invention is to provide an adhesive tape or sheet whose release layer has characteristics that allow tapes (sheets) to be stacked, has good magic ink writing properties, and has non-slip properties. [Means for Solving the Problems] As a result of intensive studies to solve the above object, the present inventors have developed a composition comprising an ethylene-α olefin copolymer, a reinforcing polymer, and an adhesion-reducing compound as a release layer. By making it the main component, it can be used not only for acrylic pressure-sensitive adhesives but also for adhesive tapes or sheets wound in a roll having a pressure-sensitive adhesive layer mainly composed of natural and/or synthetic rubber. The present invention was developed based on the findings that unwinding properties can be obtained, and that the properties of the release layer include that tapes (sheets) can be stacked, good magic ink writing properties, and non-slip properties. That is, the present invention provides an adhesive tape or sheet comprising a support provided with a release layer on one side and a pressure-sensitive adhesive layer on the other side, wherein the main component of the release layer is an ethylene-α olefin copolymer. The present invention provides an adhesive tape or sheet comprising a composition whose main components are a reinforcing polymer and a tack-reducing compound. According to the adhesive tape or sheet of the present invention, even when the main component of the pressure-sensitive adhesive layer is natural and/or synthetic rubber, good unwinding properties can be achieved without any special peeling treatment on the back surface of the tape or sheet. is obtained. Ethylene used in carrying out the present invention
The α-olefin copolymer has a density of 0.80 to 0.90 g/cm ³
It is preferable that α-olefin is an alkene with a double bond at the α-position, such as propylene, 1-
Examples include those having 3 to 8 carbon atoms, such as pentene, 1-butene, 4-methyl-1-pentene, and 1-hexene. As the ethylene-α olefin copolymer, ethylene-1-butene random copolymer,
Examples include ethylene-propylene copolymer,
One type or a mixture of several types may be used. The reinforcing polymer used in carrying out the present invention is mixed for reinforcement because the above-mentioned ethylene-α-olefin copolymer alone has low strength in the release layer, and does not have such a function. Any material can be used as long as it does not contradict the purpose of the present invention. Such things include, for example:
Examples include thermoplastic polymers such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-acrylic acid copolymer. Among such reinforcing polymers, one type or a mixture of several types of polymers having a hardness of 70 or less according to the JIS K-6301 test is particularly preferably used. Polymers with a hardness exceeding 70, especially polymers such as ethylene-vinyl acetate copolymer and ethylene-ethyl acrylate copolymer, increase the adhesive strength of natural and/or synthetic rubber-based pressure-sensitive adhesives, resulting in poor peeling effects. Become. The tack-reducing compound used in carrying out the present invention is the ethylene-α-olefin copolymer,
Compounds with lower molecular weight than reinforcing polymers are preferred, such as oleic acid amide, ethylene bisstearylamide, distearyl adipamide, erucic acid amide, hexamethylene bisoleylamide, N-oleyl Fatty acid amides such as stearylamide and ethylene bisoleylamide, surfactants such as polyoxyethylene glycol, butyl stearate, and polyoxyethylene alkyl ether phosphates, waxes such as tetrafluoroethylene, liquid paraffin, silicone oil, etc. Although it can be mentioned,
When a bisamide type fatty acid amide is used, it is particularly preferable in view of the overall properties of the tape, such as the tape's rewinding strength and adhesive strength. The blending ratio of the main components constituting the release layer of the present invention is as follows:
If the weight of the reinforcing polymer is 1, then ethylene-α
The amount of the olefin copolymer is 0.1 to 9, and the amount of the tack reducing compound is 0.001 to 2. Preferably, the amount of the ethylene-α olefin copolymer is 0.2 to 2.5, and the amount of the tack reducing compound is 0.007 per weight 1 of the reinforcing polymer. ~1
is within the range of Furthermore, the release layer of the present invention contains, in addition to the above-mentioned components,
Pigments, stabilizers,
It may also contain fillers, plasticizers, antiblocking agents, crosslinking agents, and the like. The composition of the pressure-sensitive adhesive is not particularly limited, and conventionally known pressure-sensitive adhesives such as acrylic pressure-sensitive adhesives, pressure-sensitive adhesives containing natural and/or synthetic rubber as a main component, etc. are exemplified. Ru. In particular, the effects of the present invention can be significantly achieved when a pressure-sensitive adhesive whose main component is soft and highly fluid natural and/or synthetic rubber is used. The material of the support used in the present invention is not particularly limited, and conventionally known materials may be used. For example, polyvinyl chloride resins (including resins made by copolymerizing vinyl chloride and other resins), polyolefin resins (including ethylene copolymers)
Examples include plastic films such as, paper such as kraft paper and Japanese paper, and cloth such as woven fabric and non-woven fabric. The adhesive tape or sheet of the present invention is usually a paper tube,
It is used by winding it into a roll around a synthetic resin pipe or the like with the adhesive layer inside. [Functions and Effects] The effects of using a composition containing an ethylene-α olefin copolymer, a reinforcing polymer, and an adhesion-reducing compound as the main components of the release layer are as follows. That is, by mixing the ethylene-α-olefin copolymer, the crystallinity of the release layer polymer is reduced, and among the three components, the relatively low molecular weight tack-reducing compound blooms on the surface of the release layer, reducing the tackiness. This is probably because the adhesive force between the killing compound and the pressure-sensitive adhesive layer is similar to the tensile force during unwinding. Therefore, according to the present invention, it is possible to obtain an adhesive tape or sheet that has good unwinding properties even when wound into a roll, even though no special back surface treatment is performed on the back surface. In addition, since the adhesive tape or sheet of the present invention does not require backside treatment, it is advantageous in terms of material cost and processability.
The problem of migration of the backside treatment agent to the adhesive layer can also be solved. Furthermore, the adhesive tape or sheet of the present invention
It is possible to provide a novel release layer having laminated adhesive properties, magic ink writing properties, and non-slip properties. [Examples] The fact that the adhesive tape or sheet of the present invention has good unwinding properties is demonstrated by the following examples, but the present invention is not limited to these examples. Note that "part of the text" means parts by weight. Example 1 Low density polyethylene (MI=3.7dg/min, density
0.923 g/cm ³ ), 30 parts of ethylene-propylene copolymer (density = 0.88 g/cm ³ ), and 3 parts of ethylene bisstearylamide are kneaded in a conventional manner and pelletized. A support was prepared by laminating the pellets to a thickness of 20 μm on kraft paper having a basis weight of 73 g/m ² . On the other hand, 100 parts of natural rubber, 100 parts of petroleum-based tackifying resin
1 part, using a pressure-sensitive adhesive prepared by dissolving 30 parts of process oil in toluene. Next, the pressure-sensitive adhesive is applied to the support so that the thickness after drying is 30 μm and dried to obtain an adhesive tape wound into a roll. Comparative Example 1 Example 1 except that the laminate layer of the support was composed of only one component of 100 parts of low density polyethylene.
Obtain adhesive tape in the same manner as above. Comparative Example 2 An adhesive tape was obtained in the same manner as in Example 1, except that the laminate layer of the support consisted of only two components: 70 parts of low-density polyethylene and 30 parts of ethylene-propylene copolymer. Comparative Example 3 An adhesive tape is obtained in the same manner as in Example 1, except that the laminate layer of the support consists of only two components: 100 parts of low-density polyethylene and 3 parts of ethylene bisstearylamide. The unwinding force of the above adhesive tape was measured. (Method for measuring unwinding force) The tape was rolled for 30 m/s in an atmosphere of 20°C and 65% relative humidity.
Measure the resistance when unwinding at a speed of 1 minute.

【table】

[Front] The laminate layer peeled off from the kraft paper.
Example 2 Low density polyethylene (MI=9.5dg/min, density=
0.917g/cm ³ ) 50 parts, ethylene-1-butene random copolymer (density = 0.89g/cm ³ ) 50 parts, hexamethylenebisoleylamide 4 parts, N-oleylstearylamide 0.5 parts, pigment 0.2 parts A support is prepared by laminating the composition to a base fabric (80 denier polyester fiber, number of woven fibers: 80×80 fibers/1 inch) to a thickness of 30 μm. Meanwhile, 100 parts of natural rubber, 120 parts of petroleum-based tackifying resin
Prepare a pressure-sensitive adhesive by kneading 20 parts of process oil, 20 parts of calcium carbonate, and 20 parts of calcium carbonate in a Banbury mixer. Next, the adhesive is applied to the support using a calendar roll to a thickness of 60 μm to obtain an adhesive tape. Comparative Examples 4 to 6 When the release layer composition consists of low-density polyethylene and a pigment (Comparative Example 4), when it consists of low-density polyethylene, an ethylene-1-butene random copolymer, and a pigment (Comparative Example 5), Adhesive tapes were obtained in the same manner as in Example 2 for three types (Comparative Example 6) consisting of density polyethylene, hexamethylenebisoleylamide, N-oleylstearylamide, and pigment. The unwinding force of the above tape was measured.

[Table] Example 3 80 parts of polypropylene (density = 0.90 g/cm ³ ), ethylene-propylene copolymer (density = 0.88 g/cm 3 )
cm ³ ) and 3 parts of a phosphate ester surfactant are mixed to prepare a release layer composition. On the other hand, a hot melt type pressure sensitive adhesive consisting of 100 parts of styrene-isoprene-styrene block copolymer (thermoplastic rubber), 100 parts of petroleum-based tackifier resin, and 20 parts of process oil is prepared. Next, the release composition, the polypropylene, and the hot melt adhesive are coextruded using a three-layer extruder to a thickness of 30 μm, and wound into a roll so that the adhesive layer is on the inside to obtain an adhesive tape. . Comparative Examples 7 to 9 The release composition was polypropylene only (Comparative Example 7),
Adhesive tapes were obtained in the same manner as in Example 3 using three types of adhesive tapes: polypropylene and ethylene-propylene copolymer only (Comparative Example 8) and polypropylene and phosphate ester surfactant only (Comparative Example 9). The unwinding force of the above tape was measured.

[Table] Comparative example 10 Instead of low density polyethylene, molecular weight 15000
An adhesive tape is produced in the same manner as in Example 1, except that an atactic polypropylene having . Comparative Example 11 An adhesive tape is produced in the same manner as in Example 1, except that atactic polypropylene having a molecular weight of 15,000 is used instead of the ethylene-propylene copolymer. As is clear from the above examples, the effects unique to the present invention can only be obtained when the main components of the release layer are the three components of the ethylene-α olefin copolymer, the reinforcing polymer, and the tack-reducing compound.

Claims (1)

[Scope of Claims] 1. An adhesive tape or sheet comprising a support provided with a release layer on one side and a pressure-sensitive adhesive layer on the other side, the main component of the release layer being an ethylene-α olefin copolymer. 1. An adhesive tape or sheet comprising a composition whose main components are a reinforcing polymer and a tack-reducing compound. 2. The adhesive tape according to claim 1, wherein the tack-reducing compound is a fatty acid amide. 3. The adhesive tape according to claim 1 or 2, wherein the main component of the pressure-sensitive adhesive layer is natural and/or synthetic rubber.