JPH07258610A - Pressure-sensitive adhesive tape - Google Patents

Abstract

PURPOSE: To provide a self-adhesive tape which makes use of a self-adhesive having specific physical properties, has re-adhesiveness suitable for oil-containing porous sheets, and is useful as a wound tape, a fixing member for disposable garment parts and the like.

CONSTITUTION: A self-adhesive tape made of a substrate (preferably, polypropylene, polyethylene or the like) and a self-adhesive layer wherein the self-adhesive layer consists of a self-adhesive having a glass transition temperature of -57 to -20°C and a retention time of 10 minutes or over under conditions of an adhesion area of 25 mm×25 mm, a load of 500 g and a temperature of 40°C. The self-adhesive should preferably be an acrylic self-adhesive obtained by adding 0.1 to 15 parts (by weight) of a cohesion-imparting vinyl compound such as (meth)acrylic acid to 100 parts of a 4-8C alkyl acrylate such as butyl acrylate or the like and polymerizing the mixture. In order to attain a higher cohesion, a crosslinking agent such as an epoxy compound is preferably added to the self-adhesive in an amount of 0.05 to 2 parts per 100 parts of the self-adhesive.

COPYRIGHT: (C)1995,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive tape having a re-adhesive property suitable for an oil-containing porous sheet.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
Porous sheets are used in large amounts as base materials for wound tapes, dressing materials, sanitary napkins, etc., from the viewpoint of good water vapor permeability.

Here, as the porous sheet, US Patent
As described in No. 3844865, after inorganic salt particles such as calcium carbonate are mixed in a polymer material,
Stretch-molded products are known.

However, when such a sheet is used as a surface layer of a disposable garment or the like, an adhesive tape is required to fix the sheet as a substitute for a fastener, but because of the inorganic salt particles contained in the porous sheet, the surface is not covered. There was a problem that the smoothness was poor, and the property that the inorganic salt particles migrate to the pressure-sensitive adhesive layer such as a pressure-sensitive adhesive tape and could repeat peeling and adhesion (referred to as "re-adhesion" in this specification) was not obtained. .

Therefore, US Pat. No. 4539256, US Pat. No. 4609584, and US Pat. No. 472698.
No. 9, an oil-containing porous sheet is proposed.
Here, since the oil-containing porous sheet uses oil such as mineral oil instead of the above-mentioned inorganic salt particles, it has excellent surface smoothness, has fine passage holes, and has a large surface area. Therefore, there is an advantage that an appropriate initial adhesive force can be obtained.

However, this sheet has the following problems. (A) The oil migrates to the adhesive of the pressure-sensitive adhesive tape, and the adhesive force and the cohesive force decrease with the passage of time, which may reduce the readhesion property. (B) On the other hand, the pressure-sensitive adhesive of the pressure-sensitive adhesive tape may enter into the fine pores with the passage of time, damaging the oil-containing porous sheet at the time of peeling, and reducing the re-adhesion property.

An object of the present invention is to provide a pressure-sensitive adhesive tape having a re-adhesive property, which is suitable for an oil-containing porous sheet and which solves the above problems.

[0008]

Means for Solving the Problems and Effects of the Invention The present invention provides a re-adhesive pressure-sensitive adhesive tape comprising a substrate and a pressure-sensitive adhesive layer.
-57 ~ -20 ℃, (b) pasting area 25mm
A pressure-sensitive adhesive tape having re-adhesiveness, comprising a pressure-sensitive adhesive having a holding time of 10 minutes or longer under conditions of × 25 mm, load of 500 g, and 40 ° C.

As the material of the base material, polypropylene, polyethylene, propylene-ethylene block copolymer, polyester, vinyl chloride resin, cellulose acetate, polyacetate, EVA, polyamide, polymethylpentene, paper, cotton or the like alone or in these Mixtures can be used. In particular, polypropylene or polyethylene, a block copolymer of propylene and ethylene, or a mixture thereof is suitable because it has appropriate flexibility at low temperature, is low in cost, has good back peelability, and can be easily peeled off. is there.

In addition, it is preferable to subject the substrate to a primer treatment, a matte treatment or the like in order to improve the adhesion with the pressure-sensitive adhesive, and further to perform a back surface peeling treatment in order to wind it in a roll. Is also suitable.

The thickness of the substrate in the present invention is 10 to 20.
0 μm is preferable. This is because if it is less than 10 μm, the mechanical strength is poor, the adhesive force is lowered, and it is difficult to manufacture an adhesive tape. On the other hand, if this thickness exceeds 200 μm,
This is because the adhesive tape as a whole becomes thicker, which makes it difficult to handle and reduces the creep resistance.

Further, regarding the thickness of the base material, the balance of adhesive strength, creep resistance and handleability is good, and it is 50
˜150 μm is more preferable, and 75 to 120 μm is most preferable.

The pressure-sensitive adhesive suitable for the present invention must satisfy the following requirements. (A) Glass transition point (Tg) is −57 to −20 ° C. (b) Lamination area 25 mm × 25 mm, load 500 g, 4
Must have a holding time of 10 minutes or longer at 0 ° C. The reason will be described below.

Regarding Tg, if it is lower than -57 ° C., the cohesive force at room temperature is insufficient and it tends to absorb oil and the like, so that the adhesive force remarkably decreases with the passage of time. Furthermore, the pressure-sensitive adhesive that has absorbed oil or the like enters the fine pores of the oil-containing sheet, and this porous sheet is easily damaged when the pressure-sensitive adhesive layer is peeled off. On the other hand, when Tg exceeds -20 ° C, the surface adhesiveness becomes poor and the initial adhesive strength also decreases. Therefore, from the viewpoint of such high cohesive strength and surface adhesive strength, Tg of the pressure-sensitive adhesive is more preferably −53 ° C. to −22 ° C., further preferably −40 to −25 ° C.

Here, the cohesive force of the pressure-sensitive adhesive is a general term for the attractive force acting between polymer chains, and it has a close influence on the viscoelastic behavior of the polymer. It can be improved by introducing a crosslink or a physical crosslink. However, in general, when the cohesive force is improved,
As the Tg and the like increase, the surface tackiness decreases, which causes a problem such as a decrease in the adhesive force. Therefore, the balance between the cohesive force and the Tg and the like becomes extremely important depending on the application of the pressure-sensitive adhesive.

On the other hand, with respect to the holding power of the pressure-sensitive adhesive, if the measurement conditions are less than 10 minutes, the cohesive force of the pressure-sensitive adhesive is insufficient and the pressure-sensitive adhesive is easily contaminated with oil or the like, and the adhesive force is significantly lowered with the passage of time. This is because. Further, this is also because when the pressure-sensitive adhesive enters the fine pores of the oil-containing porous sheet and the pressure-sensitive adhesive layer is peeled off, the porous sheet is easily damaged.

That is, the pressure-sensitive adhesive in the present invention solves the problems of the conventional pressure-sensitive adhesive tape by having a predetermined Tg and a predetermined holding force.

As the kind of the pressure-sensitive adhesive that can be used in the present invention, acrylic, silicon-based, urethane-based, synthetic rubber-based, natural rubber-based pressure-sensitive adhesives can be used as long as the above requirements are satisfied. It is also suitable to add a tackifier to improve surface tackiness and cohesive force. However, since the present invention is mainly intended to provide a pressure-sensitive adhesive tape having re-adhesiveness, which is suitable for an oil-containing porous sheet, excessive addition of a tackifier promotes transfer of oil to the pressure-sensitive adhesive. However, the cohesive force and the adhesive force are remarkably reduced with the passage of time, and thus must be limited.

Among these adhesives, the acrylic adhesive has tackiness by itself, and therefore, the addition of a tackifier is unnecessary or extremely small, so that oil migration is small and the cost is low. Therefore, it is particularly suitable for the present invention. Specifically, a resin obtained by adding 0.05 to 20 parts by weight of a cohesiveness imparting vinyl compound to 100 parts by weight of an alkyl acrylate and polymerizing can be used.

Here, the alkyl acrylate is isooctyl acrylate, butyl acrylate, 2-ethyl-hexyl acrylate or the like, and particularly, the preferable alkyl group of the alkyl acrylate suitable for the present invention has 4 to 8 carbon atoms. is there. This is because the alkyl acrylate in such a range has good surface tackiness of the resin obtained by polymerizing the alkyl acrylate, and can obtain a certain cohesive force.

Further, when an alkoxy acrylate is used as the alkyl acrylate of the present invention, the water vapor permeability becomes good and the gas permeability and the like of the oil-containing porous sheet are not impaired, which is preferable.

Next, the cohesiveness-imparting vinyl compound is added in order to maintain an appropriate cohesive force even when oil is contaminated. Specifically, acrylic acid, methacrylic acid and acrylamide are added. , Methacrylamide, N, N-
Dimethylacrylamide, N, N-dimethylmethacrylamide, dialkylmethacrylamide, N-vinyl-2
-Pyrrolidone Vinylpyrrolidone or the like or derivatives thereof, or polystyrene macromonomer derivatives can be used.

Here, the addition amount of the cohesiveness-imparting vinyl compound is 0.0 with respect to 100 parts by weight of the alkyl acrylate.
The reason for defining 5 to 20 parts by weight is that when the cohesiveness-imparting vinyl compound is less than 0.05 parts by weight, there is no effect of addition and the cohesive force may be insufficient, and when it exceeds 20 parts by weight, This is because Tg increases and the surface adhesive strength decreases. Further, from the viewpoint that such a balance is more favorable, it is preferable that the cohesiveness imparting vinyl compound is 0.1 to 15 parts by weight.

In addition, depending on the purpose of use, purpose of use, etc.,
In order to obtain a higher cohesive force, it is preferable to add a predetermined amount of crosslinking agent. Specific examples of the crosslinking agent include isocyanate-based and epoxy-based crosslinking agents. The addition amount of the cross-linking agent is preferably 0.01 to 3 parts by weight, and more preferably 0.05 to 2 parts by weight, based on 100 parts by weight of the entire pressure-sensitive adhesive. If the amount is out of the range of 0.01 to 3 parts by weight, the crosslinking effect may not be obtained, or the crosslinking may become excessive and the surface tackiness may be significantly reduced.

Furthermore, an antioxidant, an ultraviolet absorber or the like is added in an amount of 0.01 to 10 with respect to 100 parts by weight of the entire adhesive.
It is also preferable to add parts by weight.

Next, as another adhesive which can be used in the present invention, a resin obtained by adding 5 to 70 parts by weight of a tackifier to 100 parts by weight of the AB block copolymer is used as a main component. It is possible.

Examples of the AB type block copolymer include linear styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-butylene-.
A styrene block copolymer (SEBS), a carboxyl group-containing SEBS (C-SEBS), or a radial or star block copolymer can also be used.

The AB type block copolymer is suitable because it has two Tg's in the molecular chain and exhibits excellent cohesive force by physical crosslinking without introducing a chemical crosslinked structure.

Here, the tackifier added to the AB type block copolymer is a petroleum hydrocarbon resin, for example, a polymer of unsaturated hydrocarbon having 5 to 9 carbon atoms,
Others, terpene resin, terpene phenolic resin,
Hydrogenated terpene-based resins, rosin-based resins, rosin ester-based resins, alicyclic saturated hydrocarbon resins and the like can be specifically used, and those that absorb little oil are preferable.

The softening point of the tackifier is 0 to 150.
A tackifier with a high softening point is used for applications requiring a high cohesive force, and a tackifier with a low softening point is used for applications where low temperature is intended. Is preferred.

Further, in the pressure-sensitive adhesive suitable for the present invention, the addition amount of the tackifier is preferably 5 to 70 parts by weight with respect to 100 parts by weight of the AB block copolymer. This is because when the tackifier is less than 5, the surface tackiness is poor and an appropriate adhesive force cannot be obtained. Further, if the tackifier exceeds 70 parts by weight, the migration of oil may be promoted and the cohesive force and adhesive force may decrease with the passage of time. Therefore, from the viewpoint that such a balance is more preferable, the addition amount of the tackifier is AB
It is preferably 10 to 60 parts by weight, and most preferably 15 to 50 parts by weight, based on 100 parts by weight of the block copolymer.

The thickness of the pressure-sensitive adhesive layer suitable for the present invention is 5 to 7
It is 0 μm. When the thickness is less than 5 μm, an appropriate adhesive force cannot be obtained, and when the thickness exceeds 70 μm, it is difficult to manufacture, and the oil-containing porous sheet easily penetrates into the through holes, resulting in poor re-adhesiveness. This is because it may be difficult.

From this point of view, the thickness of the pressure-sensitive adhesive layer is preferably 10 to 65 .mu.
m, more preferably 15-60 μm.

The pressure-sensitive adhesive suitable for the present invention can be prepared by solution polymerization, emulsion polymerization, bulk polymerization, etc., but it has a high molecular weight, high adhesive strength and cohesive strength, and is safe without using a solvent. From the high point, emulsion polymerization is most suitable. The number average molecular weight of the obtained pressure-sensitive adhesive is the adhesive strength,
50,000 to 1,000,000 is preferable in terms of high cohesive force.

The oil-containing porous sheet as an adherend suitable for the present invention is, as described above, US Pat. No. 453.
The sheets described in 9256 and the like can be used. Specifically, it is mainly composed of crystalline polyolefin, contains mineral oil, etc., has uniform permeation holes of about 0.1 to 10 μm, and has a water vapor transmission rate of at least 12
^{00g / m 2 / 24Hr (32} ℃, RH 50%) is suitably a.

This is because by using a crystalline polyolefin, high mechanical strength and creep resistance can be obtained, and by containing mineral oil, etc., it has uniform and fine permeation holes, and further, This is because it has a high water vapor transmission rate and is suitable for applications such as disposable garments, sanitary napkins, and wound tapes.

The removable pressure-sensitive adhesive tape of the present invention can be produced by coating the above-mentioned pressure-sensitive adhesive on the above-mentioned substrate with a knife coater or roll coater, or laminating a hot-melt adhesive. In such a case, it is necessary to dry in an oven at about 100 ° C. for 2 minutes.

[0038]

[Examples] As the pressure-sensitive adhesives, pressure-sensitive adhesives A to N having different Tg and holding power shown in Table 1 were used, and the initial adhesive force, the aging adhesive force, and the re-adhesive property were evaluated by changing the adhesive thickness. did. Each of A to D is a mixture in which a commercially available polymer material is used as a main component and a tackifier is added thereto. E to I are copolymers obtained from the respective main components and the aggregating agent. J is a mixture of a copolymer obtained from its main component and an aggregating agent and a crosslinking agent.
M is a polymer obtained from the main component and an aggregating agent (mineral oil)
It is a mixture with. N is a mixture of a copolymer obtained from its main component and an aggregating agent and a crosslinking agent.

Tg: Determined from the peak temperature of tan δ under the conditions of compression mode, 1 rad / sec, 1 Hz by a viscoelasticity measuring device.

Holding power: A pressure-sensitive adhesive tape is stuck to a 75 mm × 75 mm oil-containing porous sheet, and the bonded body is placed vertically, and a load is applied vertically to the above-mentioned pressure-sensitive adhesive tape. The time to fall was measured. Bonding area: 25mm × 25mm Load: 500g Temperature atmosphere: 40 ° C

Criteria for evaluation of holding power: excellent good not possible <60 minutes, <20 minutes, ≧ 60 minutes ≧ 20 minutes ≧ 10 minutes <10 minutes

Initial adhesive strength: An adhesive tape was attached to an oil-containing porous sheet of 75 mm × 75 mm, and 180 ° peeling force was measured with a tensile tester under the following measurement conditions. Tape width: 25mm Pulling speed: 300mm / min Temperature atmosphere: 23 ℃, 50% RH

Aging adhesive strength: The above sample was placed at 40 ° C.
The sample was left for 24 hours in an atmosphere of 80% RH and the 180 ° peel force was measured in the same manner as the initial adhesive force.

Adhesive Strength (g / 25 mm) Evaluation Criteria: Good Good Good No 300-200-300 or 100-200 or <100 or 600 600-800 800-1000> 1000

Re-adhesiveness: A sample for measuring the initial adhesive strength was peeled off and re-attached, and the adhesive strength was 100 to 1000 g /
The number of repetitions until it was out of the range of 25 mm was measured.

Re-adhesion Evaluation Criteria: Excellent Good Poor <10, <5, ≧ 10 ≧ 5 ≧ 3 Destruction or <3

[Table 1] Example Adhesive Tg Thickness Retention Power Initial Aging Re-adhesion Type (℃) (μm) Adhesion Strength Adhesion 1 A-50 5 Good Good Good Good 2 A-50 10 Good Excellent Excellent 3 A-50 25 Good Excellent Excellent 4 A-50 30 Good Excellent Excellent 5 A-50 40 Good Excellent Excellent 6 A-50 60 Good Excellent Good 7 B-41 30 Good Good Excellent 8 C-30 30 Excellent Excellent Excellent Excellent 9 D-22 30 Excellent Good Good 10 E −55 40 Good Good Good Good 11 F −44 40 Good Good Good 12 G −34 40 Excellent Excellent 13 H −22 40 Excellent excellent 14 I-31 40 Excellent excellent Excellent 15 J-42 30 Excellent excellent Excellent Comparative Example 1 K-57 25 No No No No No 2 L-14 25 Good Good No No 3 M-65 25 No No No No 4 N 2 25 No No No No No

Content of Adhesives A to N shown in Table 1: Main component amount (parts by weight) Tackifier amount (parts by weight) Tg (° C) A KRATON D-1111 100 ARKON P-90 10 -50 B Same as above 100 Same as above 25-41 C Same as above 100 Same as above 50-30 Same as above 100 Same as above 70--22 Amount Cohesiveness amount Amount Main component (part by weight) Giving agent (part by weight) Crosslinking agent (part by weight) E 2EHA 100 AA 0.1 None − − 55 F 2EHA 100 AA 5 None − −44 G 2EHA 100 AA 10 None − −34 H 2EHA 100 AA 20 None − −22 I 2EHA / BA 90/10 AA 5 None − −31 J 2EHA 100 AA 5 L-45 0.2 -42 major amount (parts by weight) tackifier amount (parts by weight) K KRATON D-1111 100 ARKON P-90 1 -57 L Same as above 100 ditto 100 -14 amount cohesive weight amount main component (parts by weight) imparting agent (Parts by weight) Crosslinking agent (Parts by weight) M 2EHA 100 Mineral oil 12 None − −65 N 2EHA 100 AA 40 L-45 5 2 ────────────────────── ────────────── Note) KRATON (trademark) D-1111: SIS block copolymer, manufactured by Shell Chemical Co., Ltd. ARKON (trademark) P-90: Alicyclic saturated hydrocarbon resin, manufactured by Arakawa Chemical Co., Ltd. 2EHA: 2-ethylhexyl acrylate. BA: n-butyl acrylate. AA: Acrylic acid. L-45: Coronate (trademark) L-45, an isocyanate-based crosslinking agent, manufactured by Soken Chemical Co., Ltd.

The present invention can be used as a fixing material for a wound tape, a dressing material or a sanitary napkin or a component of a disposable garment.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazunori Kondo 3-8-8 Minamihashimoto, Sagamihara City, Kanagawa Sumitomo 3M Limited

Claims (6)

[Claims] 1. A pressure-sensitive adhesive tape comprising a base material and a pressure-sensitive adhesive layer, wherein the following pressure-sensitive adhesive is used in the pressure-sensitive adhesive layer, which has a re-adhesive property suitable for an oil-containing porous sheet. (A) Glass transition point is −57 to −20 ° C., (b) Lamination area 25 mm × 25 mm, load 500 g, 4
Must have a holding time of 10 minutes or longer at 0 ° C. 2. A resin obtained by polymerizing by adding 0.05 to 20 parts by weight of a cohesiveness imparting vinyl compound to 100 parts by weight of an alkyl acrylate as a main component of the adhesive. A re-adhesive pressure-sensitive adhesive tape suitable for the oil-containing porous sheet according to claim 1. 3. The pressure-sensitive adhesive tape having re-adhesiveness suitable for an oil-containing porous sheet according to claim 2, wherein the pressure-sensitive adhesive contains a crosslinking agent. 4. The pressure-sensitive adhesive as a main component comprises 5 parts by weight of a tackifier with respect to 100 parts by weight of an AB type block copolymer.
The adhesive tape having re-adhesiveness suitable for the oil-containing porous sheet according to claim 1, characterized in that a resin added by about 70 parts by weight is used. 5. The pressure-sensitive adhesive having a re-adhesive property suitable for the oil-containing porous sheet according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 5 to 70 μm. tape. 6. The pressure-sensitive adhesive tape having re-adhesiveness suitable for the oil-containing porous sheet according to claim 1, wherein the oil-containing porous sheet contains a crystalline polyolefin as a main component.