JP2003305079A - Adhesive tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive tape eliminating the need of a post process and providing an excellent practical permeability. <P>SOLUTION: In this adhesive tape, a polyethylene mixture of 30 to 50 wt.% having linear low density polyethylene and low density polyethylene and a mixture having inorganic filler of 50 to 70 wt.% are fused and filmed to provide a non-oriented film. An acrylic adhesive agent layer is stacked on a porous film substrate obtained by extending the non-extended film in one or double axial directions. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive tape having excellent air permeability, which is used for applications requiring air permeability.

[0002]

2. Description of the Related Art Conventionally, medical adhesive tapes to be applied to the skin have been required to have breathability for the purpose of preventing skin irritation and stuffiness, and various studies have been made. For example, in a method of using a highly breathable substrate such as a non-woven fabric or a cloth as the substrate of the tape, or in a bandage using a synthetic resin film as the substrate, since the substrate itself does not have air permeability, A method of providing air permeability by perforation or the like is performed. However, when a non-woven fabric or cloth is used as a base material, it is difficult to uniformly apply a certain amount of the pressure-sensitive adhesive, and such pressure-sensitive adhesive tape is not suitable for adhesive plasters or the like that require strength. . On the other hand, when a synthetic resin film is used as a base material and it is perforated by post-processing, it is difficult to make the holes smaller than a certain size, so blood or body fluid leaks from the holes and adheres to clothing etc. However, it is disadvantageous in terms of cost because it requires a step of drilling.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide a pressure-sensitive adhesive tape which is practically excellent in breathability and requires no post-process.

[0004]

The adhesive tape of the present invention comprises:
After melt-forming a mixture of 30 to 50 wt% of a polyethylene-based mixture of linear low-density polyethylene and low-density polyethylene and 50 to 70 wt% of an inorganic filler, the resulting unstretched film is uniaxially or biaxially It is an adhesive tape in which an acrylic adhesive layer is laminated on a microporous film substrate obtained by stretching.

The polyethylene-based mixture used for the microporous film substrate of the pressure-sensitive adhesive tape of the present invention is not particularly limited as long as it is a polyethylene-based mixture consisting of linear low-density polyethylene and low-density polyethylene. Measured elution amount is 15-25w at 40-60 ° C
t%, 45 to 55 wt% at 60 to 80 ° C., 80 to 100
It is preferably a polyethylene-based mixture that is 20 to 35 wt% at a temperature of ° C. Elution amount at 40-60 ° C is 15wt
If it is less than 25% by weight, moldability and stretching processability may be deteriorated and sufficient air permeability may not be obtained, and if it exceeds 25% by weight, mechanical properties of the film formed at the same time as moldability may be deteriorated. Also, the elution amount at 60 to 80 ° C is 4
If it is less than 5 wt%, the moldability is insufficient, and at the same time, the flexibility and strength of the film may be insufficient, and if it exceeds 55 wt%, the stretch processability is deteriorated.
There is a risk that it will not have sufficient breathability. Also, 80-1
If the elution amount at 00 ° C is less than 20 wt%, sufficient stretchability may not be obtained and sufficient air permeability may not be obtained, and if it exceeds 35 wt%, stretchability is poor. In addition, there is a risk that the strength of the film will be insufficient due to lack of flexibility. There is a risk that the air permeability will not be sufficient.

The amount of resin eluted by the cross fractionation method used in the present invention is a value measured as follows.
The polyethylene-based mixture is first dissolved in o-dichlorobenzene at 140 ° C or a temperature at which it is completely dissolved, cooled at a constant rate, and thin polymer layers are formed on the surface of an inert carrier prepared in advance in order of increasing crystallinity and increasing molecular weight. To generate. Next, the generated polymer layer is heated continuously or stepwise, the concentration of the eluted components is detected in sequence, and the composition distribution (crystallinity distribution) is measured. The molecular weight and the molecular weight distribution are measured by GPC type. In the present invention, a cross fractionation chromatograph device (CFC-T15) equipped with the above-mentioned temperature rising elution fractionation part and high temperature type GPC part as a system.
OA type: manufactured by Mitsubishi Chemical Co., Ltd.).

The inorganic filler used for the microporous film substrate of the pressure-sensitive adhesive tape of the present invention is not particularly limited, and calcium carbonate, barium sulfate, talc, clay, diatomaceous earth, silica and the like are preferably used. And particularly preferably calcium carbonate. Further, the inorganic filler is preferably surface-treated with a surface treatment agent such as a coupling agent, a fatty acid or a metal salt thereof in order to improve dispersibility in the polyethylene-based mixture.

The ratio of the polyethylene mixture to the inorganic filler in the microporous film substrate is 30 to 50 wt% of the polyethylene mixture and 50 to 70 wt% of the inorganic filler.
%. If the amount of the inorganic filler is less than 50% by weight, high sufficient air permeability cannot be obtained after stretching, and if it exceeds 70% by weight, the film becomes brittle and lacks strength, and at the same time, the film breaks during film formation and draw resonance (extension). Unevenness occurs and the film formability deteriorates, and a good microporous film substrate film cannot be obtained.

In the present invention, as the above-mentioned inorganic filler, 1 to 30 wt% of a clay mineral containing silicon dioxide as a main component is used.
% Inorganic fillers are preferably used. The clay mineral containing silicon dioxide as a main component means silicon dioxide SiO ₂
Containing 40 wt% or more of aluminum oxide (Al ₂ O ₃ )
, Titanium oxide (TiO ₂ ), iron oxide (Fe ₂ O ₃ ) and other metal oxide-containing natural mineral products. Specific examples include various clays such as kaolin and bentonite. These clay minerals have the effect of promoting the coagulation of blood and preventing blood leakage from micropores, so when used in a plaster or the like, the air permeability is good, and blood seeps out from the plaster or the like. Problems such as adhesion to clothes are solved.
The viscous mineral containing silicon dioxide as a main component is not particularly limited in terms of heat treatment, surface treatment, particle size, etc. as long as it has a blood coagulation promoting function, but it is an average considering film strength, productivity, etc. Fine particles having a particle size of 5 μm or less and a water content of 1% or less are preferable. The amount of the clay mineral containing silicon dioxide as a main component in the inorganic filler is 1 to 30.
wt% is preferred. If it is less than 1 wt%, the blood coagulation promoting function may be insufficient, and if it exceeds 30 wt%, the film-forming property may be lowered, or the strength and flexibility of the film may be insufficient.

The microporous film substrate is obtained by forming the above-mentioned polyethylene mixture and inorganic filler into a film and then stretching. The method of forming into a film is not particularly limited, but from the viewpoint of thinning, T
A molding method using a die is preferable. Furthermore, the stretching method may be either uniaxial stretching or biaxial stretching. Since the microporous film substrate is one in which the interface between the polyethylene-based mixture and the inorganic filler is peeled and opened in the film stretching process to develop air permeability, an increase in the content of the inorganic filler, and a stretching ratio. The air permeability can be improved by enlarging. To obtain high air permeability, draw ratio 2.0
Although it is preferably double or more, an inorganic filler containing 1 to 30 wt% of a clay mineral containing silicon dioxide as a main component having a blood coagulation-promoting function is included because the possibility of blood leakage increases as the porosity increases. Preference is given to using.

The adhesive tape used as a plaster or the like is required to have the ability to quickly remove moisture on the skin surface. Therefore, it is usually preferable that the air permeability measured by the “air permeability test method for paper and board” defined in JIS P 8117 is 100 seconds or less.

An acrylic adhesive is used in the adhesive tape of the present invention. This is because the acrylic pressure-sensitive adhesive generally has a strong adhesive force, and it is easy to design the properties of the pressure-sensitive adhesive as needed, and the quality can be further easily designed by crosslinking with a crosslinking agent. Solid content of adhesive,
The viscosity and the like are not particularly limited and may be appropriately determined according to the required performance and the manufacturing process. The acrylic pressure-sensitive adhesive layer preferably has a thickness after drying of 20 to 100 μm,
More preferably, it is 35 to 75 μm.

The cross-linking agent plays a role of increasing the cohesive force of the pressure-sensitive adhesive and improving the adhesive holding force to the adherend. Examples of the crosslinking agent include isocyanate type, aziridine type, epoxy type, metal chelate type, melamine type and modified isocyanate type. Of these, isocyanate crosslinking agents are preferably used, and polyfunctional isocyanate compounds having at least two or more isocyanate groups are more preferable. Specifically, for example, tolylene diisocyanate (TDI), diphenylmethane diisocyanate (M
DI), toluidine diisocyanate (TODI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), trimethylolpropane (TMP) -TDI adduct, polyfunctional aromatic polyisocyanate (TDI polymer, etc.), polymethylene Examples include polyphenyl isocyanate and the like, and partially modified products thereof. The amount of the cross-linking agent was 0.
It is preferable to add 5 to 10 parts by weight.

If necessary, a tackifier, a plasticizer, an antioxidant, a coloring agent, a preservative and the like may be added to the above-mentioned pressure-sensitive adhesive.

The adhesive tape of the present invention is usually supplied as a three-layer structure of microporous film / adhesive layer / release sheet. The release sheet is not particularly limited and is appropriately selected and used from those that can be used in the field.
Specific examples include silicone-coated paper and silicone-coated film. The thickness of the release sheet is not particularly limited as long as it is a thickness usually used for adhesive tapes, and may be appropriately determined as necessary.

The method for producing the pressure-sensitive adhesive tape of the present invention is not particularly limited, and it may be produced by a commonly used method,
For example, a crosslinking agent or the like is optionally added to the pressure-sensitive adhesive solution and uniformly dispersed, and the pressure-sensitive adhesive solution is applied and dried on a release sheet to form a pressure-sensitive adhesive layer, and the microporous film is formed thereon. The method of laminating is mentioned.

The pressure-sensitive adhesive tape of the present invention is suitable for use in adhesive plasters, bandages, surgical cloths, etc., but is not limited to these and may be used for any application requiring air permeability. can do.

[0018]

Embodiments of the present invention will be described below. [Preparation of Microporous Film Substrate] Based on the composition shown in Table 1, a main material LLDPE (a linear low-density polymerized with a catalyst having a single polymerization active point of 0.920 g / cm ³⁾ was used. Density polyethylene), auxiliary material LLDPE (density of polymerized using a catalyst having a plurality of polymerization active points 0.935 g / cm ³
Linear low density polyethylene), LDPE (low density polyethylene), calcium carbonate (average particle size treated with glycerin monostearate 1.3 μm), kaolin (Si
O ₂ ; 52 wt%, Al ₂ O ₃ ; 42 wt%, TiO ₂ ; 2
wt%, other; 4 wt%), and a microporous film substrate was prepared by forming a composition by a T-die method and stretching it under the conditions shown in Table 1.

[Preparation of pressure-sensitive adhesive composition] Acrylic pressure-sensitive adhesive containing a copolymer of butyl acrylate / 2 ethylhexyl acrylate / acrylic acid (weight ratio = 40/57/3) as a main component (solid content 40% by weight). ) 100 weights and a cross-linking agent (Coronate L55E, made by Nippon Polyurethane Co.) 2
0 parts by weight was mixed to prepare an adhesive composition.

[Preparation of Adhesive Tape] The above adhesive composition was applied to a polyethylene-coated polyethylene terephthalate film so that the thickness after drying would be 30 g / m ^2, and dried at 100 ° C. for 5 minutes. Immediately thereafter, the pressure-sensitive adhesive layer side was pressure-bonded to each of the microporous film base materials by a pressing roller to obtain a pressure-sensitive adhesive tape.

[Evaluation] After curing at a curing temperature of 45 ° C. for a sufficient time, the air permeability and blood leakage of each adhesive tape were measured by the following methods, and the results are shown in Table 2. (Air permeability) According to JIS P 8117 "Paper and board air permeability test method", the time required for 100 ml of gas to permeate is measured using a Gurley type air permeability measuring device (B type). did. (Blood leak) 2 x 100mm x 100mm adhesive tape
Prepare 3 sheets, drop 3 ml of animal blood on the central part of one adhesive side, attach to the other side and seal, and leave for 5 minutes, then 30
A 0 g (/ 100 mm × 100 mm) flat plate was placed on the plate, and the plate was left for 1 hour to evaluate blood leakage.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

The pressure-sensitive adhesive tape of the present invention has excellent air permeability by using a highly breathable synthetic resin film obtained by adding a specific inorganic filler to a specific polyethylene mixture as described above. Granted. Therefore, it is easy to industrially produce a breathable pressure-sensitive adhesive tape suitable for applications requiring breathability such as a medical pressure-sensitive adhesive tape with stable quality.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4C081 AA03 AA12 CA021 CA082                       CC05 CF111 CF131 CF141                       CF151 DA02 DC13 EA02

Claims (2)

[Claims] 1. A polyethylene-based mixture 30 to 50 comprising linear low-density polyethylene and low-density polyethylene.
An acrylic pressure-sensitive adhesive layer is laminated on a microporous film substrate obtained by uniaxially or biaxially stretching the obtained unstretched film after melt-forming a mixture consisting of wt% and an inorganic filler of 50 to 70 wt%. An adhesive tape characterized by being formed. 2. The pressure-sensitive adhesive tape according to claim 1, wherein the inorganic filler contains 1 to 30 wt% of a viscous mineral containing silicon dioxide as a main component.