JPH0148019B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a medical pressure-sensitive adhesive sheet having excellent elasticity, air permeability and flexibility and having a polyurethane nonwoven fabric as a base material. Here, the medical pressure-sensitive sheet is, for example, a sheet or tape used for adhesive bandages, bandages, surgical skin dressings, skin adhesives, and the like.

(Prior Art) A conventional technique for imparting stretchability and breathability to a medical pressure-sensitive adhesive sheet based on a nonwoven fabric includes, for example, creating an emulsion of a pressure-sensitive adhesive elastomer on one side of a porous nonwoven fabric having elasticity. A method of foaming and then coating is described in, for example, Japanese Patent Publication No. 50-4993. Further, a method is described, for example, in JP-A-49-97848, etc., in which a material is impregnated with a liquid that does not dissolve the air-permeable adhesive component and then laminated with a release paper coated with an adhesive solution.
Furthermore, there is also a method of dispersing an incompatible gas or liquid in the form of fine bubbles in an adhesive liquid, coating it on a release paper, heating and drying it, and then bonding it to a porous substrate, for example, as described in Japanese Patent Publication No. 51-33811. It is proposed in the Publication No.

(Problems to be Solved by the Invention) However, the stretchable or porous nonwoven fabric base materials used in these methods are all nonwoven fabrics made of inelastic materials, so even though they have stretchability, they do not break easily. The elongation is approximately 100% at most, and once elongated, permanent deformation occurs and the product cannot return to its original length, which is an unavoidable drawback. For this reason, when used in areas with strong elasticity such as joints, there are problems in that it impedes human movement and as it is stretched, it may lift off the skin. The object of the present invention is to solve the above-mentioned problems and to provide a medical pressure-sensitive sheet with sufficient elasticity, air permeability, and excellent flexibility.

(Means for Solving the Problems) It is an object of the present invention that melt-spun polyurethane elastic filaments are stacked substantially without focusing, and that the contact points of the stacked filaments are joined by the filaments themselves. becomes and 100
This is achieved by using an adhesive sheet made of a polyurethane elastic fiber non-woven fabric with a recovery rate of 85% or more upon elongation, and a non-irritating pressure-sensitive adhesive having numerous pores on one side of the fabric.

As the polyurethane elastomer constituting the nonwoven fabric used in the present invention, known melt-spun thermoplastic polyurethane elastomers are usually low melting point polyols with a molecular weight of 500 to 6,000, such as dihydroxy polyether, dihydroxy polyester, dihydroxy polycarbonate, dihydroxy Polyesteramide, etc., and an organic diisocyanate with a molecular weight of 500 or less, such as diphenylmethane diisocyanate, tolylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, 2,6
-Diisocyanate A polymer obtained by reacting methyl caproate, hexamethylene diisocyanate, etc. with a chain extender having a molecular weight of 500 or less, such as a glycol, amino alcohol, or triol. Among these polymers, particularly good are polytetramethylene glycol, polyurethane using polyε-caprolactone or polybutylene adipate as the polyol. When polyethylene glycol is used as a polyol, it improves hydrophilicity and is therefore used for special purposes. In addition, organic diisocyanates include P,
P'-diphenylmethane diisocyanate is preferred. Further, as the chain extender, P,P'-bishydroxyethoxybenzene and 1,4-butanediol are suitable.

The polyurethane elastomer is synthesized from a polyol, an organic diisocyanate, and a chain extender as described above, but in the present invention, polyurethane elastomers are preferably used in which the polyol component accounts for 65% or more of the total weight, and in particular Preferably it is 68% by weight or more. If the content of the polyol component is low, the elongation and elongation recovery of the resulting nonwoven fabric will be low.
These polyurethane elastomers may contain plasticizers, pigments, stabilizers, and the like.

The nonwoven fabric of the present invention is one in which the constituent polyurethane elastic filaments are spread and laminated over substantially the entire length of the yarn without joining.
If the monofilaments are joined in a bundled state without being opened, the flexibility of the nonwoven fabric will be significantly impaired. The monofilament usually has an average diameter of 30 microns or less, preferably 20 microns or less. The diameter of the monofilament may vary, but the maximum diameter is preferably 50 microns or less. As the fiber diameter of the monofilament increases, the nonwoven fabric becomes rough and rigid.

The cross-sectional shape of the polyurethane elastic fibers constituting the nonwoven fabric of the present invention can take various shapes such as circular, irregularly shaped, and hollow. However, from the viewpoints of post-processability, sheet formability, and stretchability as a nonwoven fabric, a circular cross section is preferable. preferable.

The nonwoven fabric of the present invention is made by laminating polyurethane elastic filaments, and the contact points between the fibers constituting this laminated body are joined by the fibers themselves. Such a bonded state can be achieved by thermally fusing the polyurethane elastic fibers together.

The important features of the nonwoven fabric of the present invention are that the nonwoven fabric has extremely high breaking strength and elongation, and has excellent elastic performance. This is because the performance directly reflects the performance of the polyurethane elastic fibers that make up the non-woven fabric, and cannot be obtained with conventional non-woven fabrics made of non-elastic polymers or non-woven fabrics made of polymers with poor elastic performance such as polyester ether elastomers. It has poor performance. The nonwoven fabric of the present invention usually has a breaking elongation of 300%.
or more, preferably 500% or more. The breaking strength is
It varies depending on the thickness of the nonwoven fabric, but usually
0.4Kg/cm, preferably 1.0Kg/cm. Also
The recovery rate at 100% elongation is usually 85% or more, preferably 90% or more. The strength, elongation, and elongation recovery rate of a nonwoven fabric vary depending on the adhesive strength of the contact points between the fibers constituting the nonwoven fabric. This indicates that the contact points are sufficiently bonded.

Another feature of the nonwoven fabric of the present invention is that it is extremely flexible. Bending resistance of non-woven fabric (JISL
-1096 (45 degree cantilever method) increases as the basis weight of the nonwoven fabric increases, but the nonwoven fabric of the present invention has a basis weight of X (g/m ² ) and bending resistance of Y (min).
Then, Y<0.2X+20, and a preferable range is Y<0.2X+10. This feature is achieved by the physical properties of the polyurethane elastic body, the structure of the nonwoven fabric of the present invention as described above, and the small diameter of the constituent fibers. This is something that could not be achieved.

As described above, the nonwoven fabric used in the present invention has sufficiently high elongation and air permeability compared to base materials used in conventional pressure-sensitive adhesive sheets, and is highly flexible and recovers even when stretched to 100%. It has an excellent feature of reaching 90%.

These properties allow the adhesive sheet obtained by applying the pressure-sensitive adhesive described below to maintain high air permeability, do not cause rashes or inflammation, and provide sufficient elongation compared to the elongation of the skin. It also helps provide a soft feel.

The basis weight of the nonwoven fabric used in the present invention is 30 to 250.
g/m ² , preferably 50-200 g/m ²
Preferably.

This is because when the viscosity of the pressure-sensitive adhesive is low, if the basis weight of the nonwoven fabric is less than 30g/ ^m2 , it will bleed onto the surface of the base material or the texture will be impaired. This is because if it is larger than m ² , the resulting adhesive sheet will lack flexibility and air permeability, and will interfere with body movement.

On the other hand, the pressure-sensitive adhesive used in the present invention may be any adhesive that is non-irritating to the skin and non-toxic, such as acrylic ester polymer type, polyvinyl alkyl ether type, natural rubber-resin type, etc. Polyisobutylene-based materials can be used as appropriate.

Adhesive liquids containing these adhesive compositions may be either emulsion type or solution type, but especially emulsion type ones are prepared by stirring a large number of fine air bubbles using an appropriate stirrer, such as a homomixer or a lab stirrer. This is preferable because it can be produced in the liquid.

As a method for applying these pressure-sensitive adhesives, known techniques such as a knife coating method, roll coating method, or roll printing method can be used. It can be printed in a pattern.

Another method is to take advantage of the property of the nonwoven fabric to be easily shaped by heat and emboss the nonwoven fabric under heat to form an uneven pattern on one side of the nonwoven fabric, and apply the pressure sensitive adhesive only to the convex portions. You can also take it.

Next, the present invention will be explained with reference to examples.

In addition, measurements of various physical property values were performed by the following methods.

Breaking strength and elongation: JIS 1096 for a 2cm wide sample
According to
The strength and elongation per cm at break are measured.

100% elongation recovery rate: A sample with a width of 2 cm is elongated to 100% with a grasping interval of 5 cm and a tensile speed of 10 cm/min, and immediately recovered to its original length at the same speed. The residual elongation rate l (%) is determined from the recorded load-elongation curve, and the 100% elongation recovery rate is calculated using the following formula.

100% elongation recovery rate (%) = 100-l/100×100 Bending resistance: Based on the 45° cantilever method of JIS L-1096.

Air permeability: JIS L-1096 Frazier type tester was used.

Example 1 5548 parts of dehydrated polytetramethylene glycol with a hydroxyl value of 102 (all parts below mean parts by weight) and 1,4-bis(β-hydroxyethoxy)
A kneader with a jacket was charged with 499 parts of benzene, and the mixture was sufficiently dissolved with stirring.The temperature was maintained at 85°C, and 1953 parts of P,P'-diphenylmethane diisocyanate was added thereto and reacted.

If stirring is continued, powdered polyurethane is obtained in about 30 minutes, which is formed into pellets using an extruder and has a concentration of 1 as measured at 25°C in dimethylformamide.
A polyurethane elastomer having a relative viscosity of 250 g/100 c.c. was obtained.

Using the polyurethane elastomer pellets obtained in this way as a raw material, a melt blow spinning device having slits for jetting heated gas on both sides of nozzles with a diameter of 0.8 mm arranged in a row was used to spin the polyurethane elastic material at a melting temperature of 245°C, with each nozzle per nozzle. Dispense the polymer at a rate of 0.15g per minute,
Air heated at 200°C was injected through the slit at a pressure of 3.5 kg/cm ² to atomize it. The fine filament was collected on a conveyor consisting of a 30-mesh wire mesh placed 25 cm below the nozzle, and then sandwiched between rollers to obtain a nonwoven fabric. In this nonwoven fabric, the intertwining points between monofilaments of polyurethane elastic fibers were joined together by fusion. The physical properties of this nonwoven fabric were as follows.

Weight 50 g/m ² -layer strength 0.3 Kg/cm Elongation at break 540% 100% elongation recovery 92% Bending resistance 20 mm Filament diameter 13 microns Air permeability 400 cc/m ² /sec On the other hand, poly(2- A dispersion containing ethylhexyl acrylate emulsion, polyvinyl methyl ether, and a nonionic activator was foamed using a homomixer, and coated on one side of the nonwoven fabric using a knife coater to give a solid content of 20 g/m ² .

Thereafter, it was dried at 130°C, and the physical properties of the resulting adhesive sheet were as follows.

Tensile strength 0.28Kg/cm Breaking elongation 510% 100% elongation recovery rate 92% Bending strength 52 mm Air permeability 350 cc/cm ² /sec This product can be used for long periods of time with no decrease in air permeability due to expansion and contraction. However, there were no symptoms such as rash,
It felt very good to the touch and was comfortable to wear.

Example 2 Fabric weight 100 obtained by the same method as Example 1
g/m ² of polyurethane elastic fiber nonwoven fabric at 130°C and 10 kg/m2 using an embossing machine with dot-shaped rolls.
It was embossed under the condition of ^cm2 . The convex part on one side of this product is made of poly(2-ethylhexyl acrylate) emulsion and polyvinyl methyl ether.
1500 cps of adhesive was applied using a kiss roll.
The printing pressure during application was 10 g/cm ² .

The obtained adhesive sheet showed no decrease in air permeability due to expansion and contraction, had a good elongation and was in close contact with the skin, felt very little resistance at this time, and had a very good feel.

(Effect of the invention) One of the important properties of the adhesive sheet thus obtained is breathability, for example, the basis weight of the sheet is 70 g/m ² (when the solid content of the pressure-sensitive adhesive is 20 g/m ² ).
The air permeability in the case ^of Because it uses , it is highly stretchable and flexible.

In other words, it has enough room to stretch compared to the stretch required for each part of the body, such as the joints, and the stress during stretching is small, and it stretches in close contact with the skin, which is not possible with conventional products. It is a nature.

The adhesive sheet according to the present invention can expand and contract even if the adhesive is uniformly applied to one side of the nonwoven fabric if the basis weight of the polyurethane elastic fiber nonwoven fabric is kept at 250 g/m ² or less and the thickness of the adhesive layer is kept appropriate. There was no problem that the air permeability was lost.

As described above, the adhesive sheet according to the present invention has sufficient elasticity and air permeability, and therefore can be applied to various uses such as adhesive bandages, bandages, surgical cloths, etc.

Claims (1)

[Scope of Claims] 1. Melt-spun polyurethane elastic filaments are stacked together without substantially focusing, the contact points of the stacked filaments are joined by the filaments themselves, and recovery at 100% elongation is achieved. A medical pressure-sensitive adhesive sheet comprising a polyurethane elastic fiber non-woven fabric having a polyurethane elastic fiber non-woven fabric having a polyurethane elastic fiber ratio of 85% or more and a pressure-sensitive adhesive that has many pores on one side and is non-irritating to the skin. 2. Claim No. 2 in which the bending resistance Y of the polyurethane elastic fiber ^nonwoven fabric is within the range expressed by the general formula Y < 0.2 1
Sheet with section description.