JPH0457712B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adhesive tape or sheet used for medical purposes, executive office purposes, etc.

Conventionally, various base materials have been used for adhesive articles, that is, so-called adhesive tapes and adhesive sheets.

For example, base materials made of film are widely used in adhesive tapes for managing directors. For executive office use, there is no problem even if the base material is impermeable, but for medical use, a problem arises. In other words, the base material does not allow the skin to breathe, resulting in a skin irritation.

For this reason, medical adhesive tapes and the like are manufactured using fiber matrix materials that allow skin to breathe, such as paper, nonwoven fabrics, and textiles. In this case, the disadvantage that the skin becomes irritated is eliminated, but the disadvantage is that the adhesive tends to ooze out to the back surface.
This causes the adhesive tape to become sticky to clothing, making it difficult to use. Adhesive tape is usually supplied in a roll, but the adhesive oozes out onto the back side, creating strong adhesion between the layers. There were cases where a so-called blocking phenomenon occurred and the tape could not be rewound and used.

The present invention aims to improve the disadvantages of adhesive articles using fibrous base materials, particularly nonwoven base materials,
The purpose of this is to use special fibers for the base material to prevent the adhesive from oozing out to the back surface.

That is, the present invention provides an adhesive article comprising an adhesive supported on one side of a nonwoven fabric base material, wherein the base material has an aspect ratio (ratio of short axis to long axis) [1]:
It has a fiber accumulation layer obtained by a carding method containing at least 20% by weight of [2 or more] flat fibers,
and an adhesive article characterized in that, in a cross section when the fiber stack is cut in the thickness direction, the angle between the long axis direction of the flat fibers and the plane direction of the fiber stack is 75° or less on average. It is related to.

The flat fibers used in the present invention mainly refer to fibers whose cross section is oval or square. In addition, the flat fibers referred to in the present invention also include those having a "dog"-shaped cross section and those having a "C" shape. Normally, the raw material fibers of nonwoven fabrics have a circular cross section, and compared to this, flat fibers have the effect of shielding holes formed between the constituent fibers.

It is necessary that the asvection ratio of the flat fibers is [1]:[2 or more]. The asvection ratio is the ratio of the short axis to the long axis in the cross-sectional shape of the fiber. If the cross section is elliptical, it will be the ratio of the short axis to the long axis of the ellipse, and if it is a quadrilateral, it will be the ratio of the short side to the long side. In the case of a "dog" shape or a "C" shape, the long axis is the line connecting the left end and the right end with a straight line, and the short axis is the thickness of the fiber. If the asvection ratio is [1]:[less than 2], the cross section will approach a circular shape, and the ability to shield holes will decrease, which is not preferable for use in the present invention. The fineness of the flat fibers may be of any value, but in order to shield the pores formed between the constituent fibers and not impair the flexibility of the finished base material, it should be approximately 10 denier or less. is preferred.

The flat fibers need to be mixed in the fiber stack in an amount of at least 20% by weight, even if the amount is small. Here, the fiber lamination layer refers to one fiber lamination layer when the nonwoven fabric is composed of, for example, two fiber lamination layers having different compositions (this is referred to as a two-layer nonwoven fabric). This also applies to nonwoven fabrics having a three-layer structure or more than three layers of fiber lamination. When the nonwoven fabric is made of a single composition, the entire nonwoven fabric is called a fiber stack. 20% by weight of flat fibers in such a layer
If less than 10% is mixed in, the effect of blocking the pores over the entire area will be poor, which is not preferable. As fibers other than flat fibers, ordinary natural fibers, semi-synthetic fibers, and synthetic fibers having a substantially circular cross section are used. As compositions of the flat fibers and other fibers, various conventionally known fibers such as polypropylene, polyethylene, polyamide, polyester, and cellulose are used.

The cross-sectional state of a fiber stack containing flat fibers cut in the thickness direction is as shown in the figure. The flat fibers look almost quadrilateral, and the other mixed fibers look circular. The reason why there are various sizes of quadrilaterals is that the flat fibers are not cut at an accurate cross section, but may be cut at an angle.

In the present invention, the angle between the long axis direction of the flat fibers and the direction of the fiber accumulation plane of the layer must be 75° or less on average. Here, the long axis direction usually coincides with the long axis of the flat fibers. However, when the aspect ratio of the flat fiber is large and the long axis is folded, the straight line connecting the left and right ends of the long axis becomes the long axis direction. The plane direction refers to the plane direction of the fiber stack, that is, the plane perpendicular to the thickness direction. In the present invention, it is important that the major axis direction and the plane direction form an angle of 75° or less on average. When the average angle is greater than 75° and approaches 90°, the long axis direction of the flat fibers is almost in the thickness direction, which has the effect of shielding pores that cause the adhesive applied to one side of the nonwoven fabric to ooze out. will be reduced. An average of 75° or less means measuring the angle between the long axis direction and the plane direction (the angle of the acute angle) in any cross section, and dividing the sum of these by the number of measurements. The specific measurement method is to take out about 5 parts where 10 to 20 flat fibers can be observed in cross section, observe each part with an electron microscope, etc., and measure the long axis direction of the flat fibers and the plane direction of the fiber stack. Measure the angle between. This can be done by finding the average of them.

A fiber stack containing flat fibers having such a specific arrangement can be obtained by forming flat fibers into a sheet while opening them using a carding method. Alternatively, the flat fibers may be opened by a card method, aggregated, and then lightly pressed. This fiber stack may be lightly needled if desired, for example to improve mechanical strength. As a result, the flat fibers tend to be arranged in the thickness direction, but there is no problem as long as the long axis direction does not tend to coincide with the thickness direction.

The nonwoven fabric base material provided with the fiber stack layer obtained in this way is used by coating one side with an adhesive. Since the flat fibers are present in a lying state in the fiber stack, the holes are shielded and the adhesive is prevented from seeping out to the back surface. When this adhesive article is used for medical purposes, it does not stick to clothing and does not cause discomfort during use. Furthermore, even when the adhesive tape is supplied in a wound form, the so-called blocking phenomenon does not occur.

The adhesive article according to the present invention has been described above mainly for medical use, but other uses include office use,
It can also be used for various purposes such as construction.

The present invention will be explained below based on examples.

Example 1 70% by weight of flat rayon fibers with an aspect ratio of [1]:[20] and a fineness of 5 denier and 30% by weight of rayon fibers with a circular cross section and a fineness of 3 denier were mixed and spread by a card method. Then, a sheet-like web having a basis weight of 25 g/m ² was formed. This web was impregnated with a polyacrylic acid ester emulsion as a binder between the constituent fibers, and then dried. The obtained nonwoven fabric had a basis weight of 50 g/m ² and a thickness of 0.08 mm.

An adhesive consisting mainly of 2-ethylhexyl acrylate and a tackifier such as polybutene was applied to one side of this nonwoven fabric substrate at a rate of 35 g/m ² . Additionally, a fluorine-based mold release agent was applied to the back side of the nonwoven fabric base material. The product thus obtained was cut into a tape shape with a width of 2.5 mm and a length of 5 m, and then wound to form a roll.

When this scroll was continuously kept in an atmosphere at 50°C, no so-called blocking phenomenon occurred even after 70 days had passed.

Comparative example Rayon fiber 100 with a circular cross section and a fineness of 3 denier
% by weight was opened by a card method to form a sheet-like web with a basis weight of 25 g/m ² . This was impregnated with the same interfiber binder as used in Example 1,
It was dried to produce a nonwoven fabric with a basis weight of 50 g/m ² and a thickness of 0.15 mm. Thereafter, a roll of adhesive tape was obtained in the same manner as in Example 1, and the same experiment was conducted. This result 14
After a few days had passed, a so-called blocking phenomenon occurred and the device became unusable.

Example 2 ^A web (A
layer) was created. Further, 100% by weight polyester fibers having a circular cross section and a fineness of 3 denier were opened by a carding method to prepare a web (layer B) having a basis weight of 30 g/m ² . After layer A and layer B were laminated, the fabric was impregnated with an emulsion of polyacrylic acid ester as an interfiber binder and dried to obtain a nonwoven fabric of 100 g/m ² . On the A layer side of this nonwoven fabric, an adhesive mainly made of natural rubber is applied.
It was applied at a rate of 150 g/m ² to obtain an adhesive sheet.

Paper was placed on the back side of the nonwoven fabric base of this adhesive sheet, a pressure of 1 kg/100 cm ² was applied, and the sheet was kept in an atmosphere of 50°C. No oozing of the adhesive was observed even after 70 days had passed.

Comparative example: Polyester fiber with a circular cross section and a fineness of 3 denier
100% by weight was opened using the card method to obtain a fabric weight of 50.
A web with a weight of 100 g/m ³ was prepared in the same manner as in Example 2 to produce a nonwoven fabric with a basis weight of 100 g/m ³ . Thereafter, an adhesive sheet was obtained in the same manner as in Example 2, and tested in the same manner. As a result, this adhesive sheet
After 10 days, oozing was seen on the back.

[Brief explanation of the drawing]

The drawing schematically shows a cross section of a fiber stack containing flat fibers cut in the thickness direction and observed with an electron microscope.

[Claims]

1. For 100 parts of aliphatic or aromatic polyhydric alcohols or phenols, 10 to 1000 parts of lignocellulose material such as wood that has been made into plastic by introducing at least one substituent to some or all of the hydroxyl groups. In addition, a method for producing a plasticized lignocellulose epoxy resin adhesive, characterized in that it is dissolved using solvolysis, and then epichlorohydrin is added and condensed to form a glycidyl ether. 2. A method for producing a plasticized lignocellulose epoxy resin adhesive according to claim 1, in which solvolysis using aromatic or aliphatic polyhydric alcohols or phenols is carried out in the presence of a catalyst that promotes solvolysis of lignin. . 3 The catalyst that promotes solvolysis by aromatic or aliphatic polyhydric alcohols or phenols is
3. The method for producing a plasticized lignocellulose epoxy resin adhesive according to claim 2, wherein the acid includes a mineral acid or a Lewis acid. 4. A catalyst that promotes solvolysis by aromatic or aliphatic polyhydric alcohols or phenols,
The method for producing a plasticized lignocellulose epoxy resin adhesive according to claim 2, wherein the adhesive is caustic soda or an alkali containing caustic potash.