JPH10298513A - Repeelable adhesive label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive label capable of adhering to a material to be adhered, such as papers, plastics, metals, etc., further capable of repeeling the adhered label again after adhering the label, and hardly fouling the material to be adhered. SOLUTION: This adhesive label having an adhesive layer at one surface of a surface substrate comprises the adhesive layer regulated so that the logarithmic decrement of the adhesive layer measured by a rigid body pendulum type physical property testing machine may have the maximum between (-100) deg.C and (-60) deg.C and >=0.5 maximum value, and the value (Δ0 ) of the logarithmic decrement at 0 deg.C and the value (Δ40 ) of the logarithmic decrement at 40 deg.C may satisfy the following formulas (1) to (3):(1): 0.70<=Δ40 /Δ0 <=3.00; (2): Δ40 <=0.30; and (3): Δ0 <=0.30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a removable adhesive label. Specifically, the present invention relates to an adhesive label that can be attached to an adherend such as paper, plastic, or metal, can be peeled off again after the adherence, and does not contaminate the adherend with an adhesive.

[0002]

2. Description of the Related Art Conventionally, pressure-sensitive adhesive labels have been used for applications such as notation of various product names, prices, precautions, etc., packaging and binding. Normally, the adhesive label had a sufficient adhesive strength to an adherend so that print information or the like written on the adhesive label would not peel off the adhesive label. However, when the adherend is metal or glass, it can be moistened with a solvent, or the adhesive label attached by mechanical friction can be peeled off, and the adhesive remaining on the adherend can be removed.
When this method is used for plastics and papers, the plastics may be eluted, or the papers and plastics may be damaged, thereby impairing the commercial value of the adherend itself.

[0003] In recent years, pressure-sensitive adhesive labels have come to be used in the distribution stage and manufacturing process of commodities. Products are distributed through shops, wholesalers, etc., from producers such as factories to general consumers. When transporting between these distributions, the destination,
An adhesive label on which product information such as a lot number, grade, and quantity is printed is attached, and after the adhesive label is peeled off cleanly at the receiving stage, another adhesive label may be attached again to the next destination. In this case, if the pressure-sensitive adhesive label does not have removability, several types of different pressure-sensitive adhesive labels are stuck to the product or the wrapping paper, and there is a problem that the destination and the product information are confused. In addition, methods such as forcibly peeling off the adhesive label or attaching a new adhesive label on the adhesive label are not preferable from the viewpoint of appearance, such as the peeling off of the adhesive label and the sticking out of the adhesive label.

Further, confidential and concealed postcards in which an adhesive label is attached to a postcard have been studied. Although postcards have lower postage rates than sealed letters, if the items described on the back have confidentiality, they have the disadvantage of being read by a third party. When a conventional adhesive label is attached to the printing surface of a postcard, the adhesive strength increases after the attachment and before the mail is delivered, and the adhesive label's paper peeling or postcard is torn,
Printing adheres to the adhesive surface of the adhesive label, so that the printing cannot be read and accurate information cannot be transmitted. Conversely, in the case of an adhesive label using an adhesive with low adhesive strength, the postcard is likely to be peeled off due to bending of the postcard or the friction of a roller, etc., and the adhesive label may be peeled off and adhered to the machine in a mail sorting machine. Attaching to other postal matter creates a problem, and reduces the efficiency of postal services. In addition, there has been a problem that the adhesive label has not been well-balanced in the past, such as a problem that the adhesive label peels off when the delivery member bundles it or folds the postcard by mistake during mail delivery. .

[0005] Another method is to laminate a postcard printing surface with a film or the like, cover it with a high-adhesive pressure-sensitive adhesive label, and attach two layers of the film in a pseudo-adhesive manner. Labels with a concealing layer on the surface are also conceivable and are already on the market, but since the film is laminated on the printed surface, water resistance is improved, but writing on a laminated surface such as a pencil, ballpoint pen, water-based pen, etc. Properties and vermilion sealability are lost. Laminating the printed surface of important documents that require post-consent or signature is not suitable because it is impossible to fill out and seal the printed surface. In addition, since it has a configuration of a plurality of layers, the cost is high.

As another inexpensive method, for example, using an information carrier sheet described in JP-A-64-85794, JP-A-64-85795, JP-A-4-59395, etc. At the time of tri-folding, a special nip device performs high-speed and large-volume crimping, so it is suitable for direct mail or the like, but not suitable for putting out a small amount of postcards between individuals. Further, when printing on a postcard, 5 to 20 parts containing a large amount of components such as starch and natural rubber are used.
Since printing is performed on a μm resin layer, the printed surface may be eluted by accidentally immersing it in water, or if the postcard is stored for several years, the resin layer may fall off along with the printed surface due to deterioration of the resin layer such as natural rubber. Therefore, it is not suitable for important documents that are to be stored for several decades, and important documents that do not lose their prints even if they are washed by mistake.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an adhesive label having a releasable property which is used by attaching it to paper, plastic, or metal, or which is used in a distribution stage or a manufacturing process. The label does not float or peel off from the adherend when attached to the body, and the adhesive adheres to the adherend when the adhesive label is peeled off, or the adhesive label base material breaks and adheres to the adherend. An object of the present invention is to provide an adhesive label that can be peeled off without any problem. Another object of the present invention is to provide a concealing label that can be easily peeled off by a recipient without causing unintended peeling even when the label is attached to a postcard or the like.

In general, the pressure-sensitive adhesive used for the pressure-sensitive adhesive label is a rubber-based pressure-sensitive adhesive obtained by mixing a polymer having rubber elasticity at room temperature, such as natural rubber, SIS, or SBS, with a tackifying resin, a plasticizer, and an antioxidant. When the carbon number of the alkyl group is 4 to
Acrylic pressure-sensitive adhesives mainly composed of 12 alkyl acrylates or alkyl methacrylates are used. Further, as an adhesive having removability, for example, Japanese Patent Publication No. 5-75034 has been proposed. However, at present, the above problem cannot be solved even by using such a pressure-sensitive adhesive having removability.

[0009]

Means for Solving the Problems The present inventors have conducted analysis and research on the state and the like when a person peels off an adhesive label from an adherend.
Peeling speed: 0.3 m / min to 60 m / min, temperature: 0
It has been found that it is necessary to be able to stably peel in an atmosphere at a temperature of from 40 ° C to 40 ° C.

A conventional adhesive label has a peeling speed of 0.3 m / min and a test temperature of 22 as defined in a test method such as the JIS standard.
It was evaluated at ° C., and those having re-peelability under these conditions were used as re-peelable adhesive labels. However, in actuality, the peeling speed varies from 0.3 m / min to 60 m / min, and even with the conventional adhesive label for re-peeling, when peeling at a high speed of 60 m / min, the adhesive strength increases, and the adhesive strength is increased. There is a problem that the balance between the strength of the label base material and the strength of the adherend is broken, and the removability is lost. At a low temperature such as 0 ° C., the pressure-sensitive adhesive becomes hard and the adhesive strength becomes high, so that the adhesive loses re-peelability. At a high temperature such as 40 ° C., the pressure-sensitive adhesive softens and the pressure-sensitive adhesive aggregates. Because the power decreases,
When the pressure-sensitive adhesive label is peeled off, the pressure-sensitive adhesive remains on the adherend, and there is a problem that the adherend is contaminated.

In general, there are many types of adherends, such as paper, plastic, and metal, and the surface has various irregularities. Therefore, the degree to which the adhesive of the adhesive label adheres to the adherend is different. Therefore, the adhesive strength differs depending on the type of the adherend. However, consumers who apply an adhesive label have a problem that even if the adhesive label has removability to be applied regardless of the adherend, the adhesive force differs depending on the type of adherend and the adhesive force becomes too low. There are problems such as peeling of the pressure-sensitive adhesive label from the adherend, and conversely, loss of removability due to excessively high adhesive strength. For example, when a conventional adhesive label having removability is adhered to paper, problems such as poor conformability to deformation, such as bending and folding, of the adherend paper, forming a cavity (tunnel), floating, and peeling are problems. was there.

[0012] The present inventors have found that in such an adhesive label having removability, an adhesive adheres to an adherend,
As a result of intensive studies on the cause of the adhesive label's adhesive strength becoming high enough to destroy the adhesive label substrate, the value of the logarithmic decay rate measured by a rigid pendulum type physical property tester on the adhesive surface of the adhesive label was identified. It was found that doing so could solve the problem.

That is, the present invention relates to a pressure-sensitive adhesive label having a pressure-sensitive adhesive layer on one surface of a surface substrate, wherein the pressure-sensitive adhesive layer has a logarithmic decrement of -10 using a rigid pendulum type physical property tester.
There is a maximum value at 0 to -60 ° C, the maximum value is 0.5 or more, and the value of the logarithmic decay rate at 0 ° C (Δ ₀ )
And a value of a logarithmic decrement at 40 ° C. (Δ ₄₀ ) satisfying the following formulas (1) to (3). 0.70 ≦ Δ ₄₀ / Δ ₀ ≦ 3.00 (1) Δ ₄₀ ≦ 0.30 (2) Δ ₀ ≦ 0.30 (3)

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The pressure-sensitive adhesive layer of the pressure-sensitive adhesive label of the present invention uses a rigid pendulum type physical property tester and a pressure-sensitive adhesive having specific physical properties. In the present invention, the measurement was performed using a rigid pendulum type physical property tester (RPT-α100, manufactured by Tohoku Electronics Co., Ltd.). This tester is a physical property tester utilizing the free damping vibration of a pendulum. In the present invention, a pendulum frame is a knife-shaped edge having a weight of 47.3 g, and the pendulum is set such that the fulcrum and the working point of the pendulum are in contact with the adhesive applied surface of the adhesive label. The pendulum is freely attenuated at 10-second intervals in a temperature range of −120 to 200 ° C., at a heating rate of + 5 ° C./min and a cycle of 0.6 second, and the logarithmic decay rate at that time is measured.

In general, there are a fulcrum and a working point of a pendulum in a coating film of a coating layer. When the pendulum is freely vibrated, there is repulsion of the coating layer inside the working point, and the opposite side of the working point is a coating layer. The vibration of the pendulum changes depending on the thermoplastic and mechanical properties of the coating layer. Normal adhesive is -80 ~
It has a maximum value of the logarithmic decay rate in a temperature range of 20 ° C., and thereafter, the logarithmic decay rate gradually decreases as the temperature increases. When the temperature is further increased, the logarithmic decay rate of some adhesives slightly increases. At the temperature at which the logarithmic decay rate reaches its maximum value, the main chain structure of the resin forming the coating film vibrates best and the coating film surface softens, and the vibration of the pendulum is braked and shows the maximum value . After that temperature, the movement of the main chain structure of the resin is suppressed, the vibration is hardly attenuated, and the logarithmic decay rate decreases.

[0016] The logarithmic decrement is, there are 0.5 or more maximum at -100 to-60 ° C., further, the value of the logarithmic decrement (delta ₀₎ at 0 ° C., the logarithmic decrement at 40 ° C. The value (Δ ₄₀ ) is characterized by having an adhesive layer satisfying the following formulas (1) to (3). 0.70 ≦ Δ ₄₀ / Δ ₀ ≦ 1.30 (1) Δ ₄₀ ≦ 0.30 (2) Δ ₀ ≦ 0.30 (3)

Incidentally, the maximum value of the logarithmic decay rate is -100 ° C.
When present at lower temperatures, the adhesive label will
In such an environment, the cohesive force of the pressure-sensitive adhesive decreases, and when the pressure-sensitive adhesive label applied in advance is peeled off from the adherend, the pressure-sensitive adhesive causes cohesive failure and remains on the adherend. Conversely, when the maximum value of the logarithmic decay rate is higher than −60 ° C., the pressure-sensitive adhesive label is
When the adhesive strength at 40 ° C. is increased, the base material of the adhesive label is broken when the adhesive label is peeled off from the adherend.

The maximum value of the logarithmic decay rate is -100 to-
Even at 60 ° C, the maximum value is less than 0.5
Has a maximum value of -100 to -60 ° C used for adhesives.
The performance of the main polymer is difficult to achieve, and the adhesive strength of the adhesive label
Becomes too low and peels off from the adherend. Furthermore, on
In the case where notation (3) is not satisfied, that is, the logarithmic decrease at 0 ° C.
Decay value (Δ ₀) Exceeds 0.30, the viscosity at 0 ° C
The adhesive is not completely rubberized and loses tackiness. the above
When the formula (2) is not satisfied, that is, the logarithmic decrease at 40 ° C.
Decay value (Δ₄₀) Exceeds 0.30, the viscosity at 40 ° C
The adhesive plasticizes, loses the cohesive strength of the adhesive force, and removes the adhesive label.
Glue remains on the adherend when peeled from the adherend. In addition,
When formula (1) is not satisfied, adhesion at 0 ° C. and 40 ° C.
The difference in force becomes too large, the temperature range of 0 ° C to 40 ° C,
Alternatively, it shows re-peelability at a peel speed of 0.3 to 60 m / min.
No adhesive label is obtained.

Among such pressure-sensitive adhesive layers exhibiting a specific logarithmic decrement, the dynamic shear modulus of the pressure-sensitive adhesive at a frequency of 1 Hz and a temperature of 22 ° C. measured by a DMA (dynamic analyzer) is 1.0 ×. 10 ^{5 to} 1.0 × 10
⁸ (dyne / cm ² ), 0 ° C., dynamic shear modulus (G ′ ₀ ), and dynamic shear modulus at 40 ° C. (G ′ ₄₀ )
Is preferably an adhesive satisfying the following formula (4). 0.7 ≦ G ′ ₄₀ / G ′ ₀ ≦ 5.0 (4)

The dynamic shear modulus of the pressure-sensitive adhesive measured by a DMA (Dynamic Analyzer) is, for example, an apparatus such as Leo Vibron DDV-01 / 25FP (manufactured by Orientec Co., Ltd.) having a length of 0.1 mm. 3cm,
Two pieces of adhesive having a height of 1.5 cm and a width of 2.0 cm were set on a shearing jig, and the adhesive was sheared and deformed by vibrating from one end of the jig, and was vibrated on the opposite side of the jig. The complex shear modulus and the dynamic shear modulus of the adhesive can be calculated by detecting the load.

Generally, the dynamic shear modulus indicates the hardness of an object to be measured. As the dynamic shear modulus of the pressure-sensitive adhesive increases, the cohesive strength of the pressure-sensitive adhesive increases. Conversely, when the dynamic shear modulus of the pressure-sensitive adhesive decreases, the cohesive strength of the pressure-sensitive adhesive decreases. In the present invention, the dynamic shear modulus at 22 ° C. of an adhesive used for an adhesive label having removability is 1.0 × 10 ⁵ to
It is preferably 1.0 × 10 ⁸ (dyne / cm ² ). Incidentally, the dynamic shear modulus of the adhesive is 1.0 × 10 ⁸ (dyn
e / cm ² ), the internal stress of the pressure-sensitive adhesive increases with the cohesive force of the pressure-sensitive adhesive, and the adhesive strength of the pressure-sensitive adhesive label to the adherend increases. There is a risk of destruction. Conversely, 1.0 × 10 ⁵ (d
If it is less than yne / cm ² ), the cohesive force of the pressure-sensitive adhesive decreases together with the internal stress of the pressure-sensitive adhesive, and the cohesive force of the pressure-sensitive adhesive label is lower than that of the pressure-sensitive adhesive label. In this case, cohesive failure may occur, and the adhesive may remain on the adherend.

When the pressure-sensitive adhesive used for the pressure-sensitive adhesive label described above has a dynamic shear modulus of 0 to 40 ° C., the ratio of the dynamic shear modulus (formula (4)) is 0.7. ~
It is preferably 5.0. If the temperature exceeds or falls short of this range, the cohesive force and internal stress of the pressure-sensitive adhesive greatly change in the range of 0 ° C to 40 ° C. There is a possibility that the adhesive may remain on the adherend due to the temperature change of the label, the adhesive label may be broken in the base material, or the adhesive label may drop naturally from the adherend.

The pressure-sensitive adhesive used for the pressure-sensitive adhesive label may be a pressure-sensitive adhesive satisfying the above-mentioned condition of the logarithmic decrement, or a pressure-sensitive adhesive satisfying a condition obtained by adding a condition of a dynamic shear modulus to the above condition. There is no particular limitation as long as it uses. In order to satisfy such conditions, it can be obtained by appropriately selecting and blending a tackifier, a cross-linking agent, a plasticizer, an oil, and the like to the adhesive main agent.

Above all, an acrylic acid ester or a methacrylic acid ester having an alkyl group having 8 to 12 carbon atoms, preferably 8 to 10 carbon atoms, is used as the main adhesive agent.
An acrylic pressure-sensitive adhesive containing 9% by weight is preferred, and will be described in detail below.

Specific examples of the acrylate having an alkyl group having 8 to 12 carbon atoms include 2-ethylhexyl acrylate, n-octyl acrylate, isononyl acrylate and lauryl acrylate. Examples of the alkyl methacrylate having 8 to 12 carbon atoms in the alkyl group include 2-ethylhexyl methacrylate, n-octyl methacrylate, isononyl methacrylate, and lauryl methacrylate. These alkyl acrylates or alkyl methacrylates alone or
More than one type can be used in combination. Preferably, 2-ethylhexyl acrylate and isononyl acrylate, and the weight ratio of 2-ethylhexyl acrylate to isononyl acrylate is 97/3 to 2
A value of 0/80 is more preferable.

The ratio of the above-mentioned monomer or mixture of the alkyl acrylate or alkyl methacrylate as the main adhesive to the total solid content is 70 to 9%.
It is 9.9% by weight, preferably 80 to 98% by weight. 7
If it is less than 0% by weight, the logarithmic decay rate measured by the target rigid pendulum type viscoelasticity measurement and the dynamic shear modulus measured by DMA cannot be obtained at 0 to 40 ° C., and the adhesive strength becomes high. The adhesive label loses releasability, the adhesive label is broken from the adherend, and the adhesive label cannot be peeled off without adhesion. Also, 9
If the amount exceeds 9.9% by weight, the cohesive force of the pressure-sensitive adhesive decreases, and the pressure-sensitive adhesive easily adheres to the adherend when peeling the pressure-sensitive adhesive label from the adherend.

Incidentally, 0.1 to 30% by weight of the pressure-sensitive adhesive is used in order to improve the pressure-sensitive adhesive performance of the above-mentioned pressure-sensitive adhesive main ingredient, such as an acrylic monomer having a crosslinking point, a functional monomer, a plasticizer or a surfactant, a tackifier, A curing agent or the like can be appropriately compounded.
For example, the alkyl group copolymerizable with the above monomer has 4 to 4 carbon atoms.
An alkyl acrylate or alkyl methacrylate which is 8. Other monomers having a functional group copolymerizable with the above monomers. For example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, isopropyl acrylate, isopropyl methacrylate,
Butyl acrylate, butyl methacrylate, hydroxyalkyl acrylate, hydroxyalkyl methacrylate, methoxyethyl acrylate, ethoxymethyl acrylate, glycidyl methacrylate, acrylamide, methacrylamide, styrene, N-methylolacrylamide, N-methoxybutylacrylamide, α-
Unsaturated carboxylic acids, β-unsaturated carboxylic acids and the like. A plasticizer having a glass transition temperature of −70 to 10 ° C. or a surfactant having a plasticity with respect to a main component. For example, oils such as naphthenic process oils and paraffinic oils, plasticizers such as dioctyl phthalic acid, and surfactants. Known tackifier. For example, stabilized rosin glycerin ester, β-pinene resin, terpene resin obtained by polymerizing α-pinene resin, C5 petroleum resin, C9 petroleum resin, and the like. A curing agent represented by a polyglycidyl compound having two or more epoxy groups or a glycidyl ether of a polyhydric alcohol. Additives other than the above. For example, antifoaming agents, thickeners, preservatives, antibacterial agents, pigments, antifreezing agents and the like. Are blended.

Among these materials, monomers which can be copolymerized with the alkyl acrylate which is the main component of the pressure-sensitive adhesive are copolymerized with the main monomer when the pressure-sensitive adhesive is polymerized. Those that do not copolymerize with the main monomer, such as a tackifier and a plasticizer, are added directly to the polymerized pressure-sensitive adhesive or dispersed separately from the pressure-sensitive adhesive by a method such as emulsification and dispersion. In addition, since the curing agent is mixed with the adhesive and reacts with the adhesive after a while and gels or forms aggregates, it is easy to cause trouble in applying the adhesive, so immediately before applying the adhesive, 2
It should be added within 4 hours. Additives are appropriately added so that the properties of the adhesive, such as viscosity and pH, do not change due to aggregation and sedimentation during long-term storage when the adhesive is coated with the adhesive, but if the adhesive is present in an excessive amount in the adhesive, It should be incorporated as little as possible, as it has an adverse effect on the adhesive properties.

In the present invention, the pressure-sensitive adhesive is obtained by copolymerizing the above-mentioned monomer by emulsion polymerization or suspension polymerization. Even with a method such as solution polymerization, it is possible to polymerize the pressure-sensitive adhesive having the desired dynamic shear modulus, but the viscosity of the pressure-sensitive adhesive after polymerization becomes too high, and it is not preferable because it becomes difficult to handle as a coating liquid. .

Examples of the method of emulsion polymerization include the above monomer mixture, ion-exchanged water, polyoxyethylene nonyl phenyl ether, polyoxyethylene phenyl ether.
Surfactants such as sulfate ammonium sulfate, polyoxyethylene alkyl ether sulfosuccinate disodium salt, sodium lauryl sulfate, sodium decylbenzenesulfonate, potassium persulfate, ammonium persulfate, azobisisobutyronitrile, peroxide And a polymerization initiator such as butyl mercaptan, decyl mercaptan, isopropyl alcohol, methanol, carbon tetrachloride, etc., to prepare a pre-emulsion. In another reaction vessel, 5 to 30% by weight of the pre-emulsion and water are added, and the mixture is stirred in an inert gas atmosphere to perform initial polymerization. The pre-emulsion is dropped into the reaction vessel while the solution is further stirred, and polymerized to polymerize the target adhesive.

Two or more epoxy groups, preferably 2 to 4
The curing agent such as a polyglycidyl compound or a glycidyl ether of a polyhydric alcohol contained therein is adjusted by being blended at a ratio of 0.2 to 3 equivalents per equivalent of the carboxyl group in the polymer. If the amount of the curing agent is less than 0.2 equivalent per equivalent of carboxyl group in the polymer, the cohesive force of the adhesive is insufficient, and the adhesive remains on the adherend when the adhesive label is peeled off from the adherend. Conversely, if the amount of the curing agent exceeds 3 equivalents, the pressure-sensitive adhesive loses adhesiveness to the adherend, and the pressure-sensitive adhesive label peels off or adheres to the adherend after the pressure-sensitive adhesive label is attached to the adherend. The adherend is easily peeled off due to deformation.

As the surface substrate (label paper) constituting the pressure-sensitive adhesive label, a known substrate used for a label can be used. For example, paper such as high quality paper, coated paper, art paper, cast coated paper, kraft paper, etc., and biaxially oriented PET (polyethylene terephthalate) film, OPP (biaxially oriented polypropylene) film, and thermoplastic resin such as nylon film are used as raw materials. Plastic films, synthetic papers mainly made of polypropylene, polystyrene and the like, as well as woven fabrics and non-woven fabrics. Further, a known recording material such as a heat-sensitive recording medium having a heat-sensitive recording layer on the surface substrate, a heat transfer receiving sheet having a heat transfer receiving layer, or an ink jet recording paper having an ink receiving layer may be used. Needless to say, a laminated body in which the surface base material is laminated in a plurality of layers may be provided, and a metal deposition layer, a printed layer, and a colored layer may be provided.

Usually, the pressure-sensitive adhesive label has its pressure-sensitive adhesive layer protected by a release sheet. As the base material of the release sheet,
Paper such as high-quality paper, glassine paper, coated paper, art paper, cast coated paper, kraft paper, biaxially oriented PET (polyethylene terephthalate) film, OPP (biaxially oriented polypropylene) film, thermoplastic resin such as nylon film A plastic film as a raw material, a synthetic paper mainly made of polypropylene or polystyrene, or a laminate obtained by laminating a thermoplastic resin such as polyethylene or ethylene-vinyl acetate copolymer on the above-mentioned base material or a sealing layer. Coated ones are used. A release agent such as a silicone-based release agent, a long-chain alkyl group-based release agent, a fluororesin-based release agent, or a shellac resin is applied to one or both surfaces of the substrate, and the coated amount after drying is 0.01 to 5 g / m ^2. Preferably, those coated with 0.01 to 3 g / m ² can be used.

As a device for applying the pressure-sensitive adhesive, for example, a reverse roll coater, a reverse gravure coater, a lip coater, a knife coater, a bar coater, a die coater, a screen printing machine and the like are appropriately used. The method of transferring the adhesive to the adhesive label substrate surface by applying the adhesive to the release agent coated surface of the release paper, drying in an oven and bonding the adhesive to the adhesive adhesive surface of the label substrate is usually preferable. In order to enhance the adhesiveness between the adhesive and the adhesive label substrate, a method of performing anchor coating on the adhesive-adhesive surface of the adhesive label substrate or directly applying the adhesive to the adhesive label substrate and drying is used. No problem.

The amount of the adhesive applied is such that the weight after drying is 3 to 5
0 g / m ^2, preferably, coated as a 5 to 30 g / m ^2. By the way, when the coating amount of the adhesive is less than 3 g / m ² , the adhesive force to the adherend is insufficient, so that when the adhesive label is applied to the adherend, the adhesive label may peel off from the adherend. There is. Conversely, the amount of adhesive applied is 50g
When the adhesive label is more than / m ² , the adhesive force to the adherend becomes too high compared to the cohesive force of the adhesive, so that the adhesive remains on the adherend when the adhesive label is peeled off from the adherend. It is desirable that the adhesive applied surface has no foaming or unevenness. If the adhesive applied surface has irregularities due to foaming, uneven application, or the like, the upper paper of the label also has an irregular shape, and the printing suitability at the time of printing and printing is reduced.

[0036]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted thereto.

Example 1 (Polymerization of pressure-sensitive adhesive) In an autoclave equipped with a stirrer, a temperature controller and a reflux condenser, 40 parts by weight of ion-exchanged water and 0.1 part by weight of ammonium persulfate as a polymerization initiator were added. Temperature. Next, 98 parts by weight of 2-ethylhexyl acrylate and 1 part by weight of acrylic acid as main ingredients, 0.05 part by weight of n-butyl mercaptan as an additive, 1 part by weight of sodium dodecylbenzenesulfonate, 1 part by weight of polyoxyethylene nonyl phenyl ether, After the addition, the mixture was stirred and emulsified to prepare a pre-emulsion. 10 parts by weight of this pre-emulsion and 60 parts by weight of ion-exchanged water are mixed, and the mixture is stirred and heated while being purged with nitrogen gas, and is subjected to initial polymerization at 80 ° C. for 30 minutes.
Drop the remaining pre-emulsion over 3 hours,
Stirring was further performed for 2 hours for aging, and ion-exchanged water was added to obtain an adhesive having a solid content of 50% by weight.

(Production of pressure-sensitive adhesive label)
64g / m^TwoQuality paper (Product name: OK Prince, King
Co., Ltd.). The release sheet is blue
82 g / m thin paper^Two Silicone release agent for base paper
(Product name: KS-772, manufactured by Shin-Etsu Chemical Co., Ltd.)
The later coating amount is 1.0 g / m ^Two Mayer bar to be
To give a release sheet. Apply adhesive to the release sheet
Two hours before the work, 200 parts by weight of the adhesive were used as a curing agent
As polyethylene glycol diglycidyl ether 1
Parts by weight were added and stirred. The label is
Adhesive with the above curing agent added to the release agent coated surface of the sheet
Coating amount after drying is 6.0 g / m^Two Commaco
After drying, dry the adhesive coated surface and label paper.
The label was obtained by bonding with the rough surface.

Example 2 An adhesive label was produced in the same manner as in Example 1 except that the adhesive was applied so that the coated amount of the adhesive after drying was 30 g / m ² .

Example 3 (Polymerization of PSA) The procedure of Example 1 was repeated except that the main ingredients contained in the PSA were 25 parts by weight of 2-ethylhexyl acrylate, 71 parts by weight of isononyl acrylate, and 2 parts by weight of acrylic acid. The adhesive was emulsion polymerized by the method. (Production of pressure-sensitive adhesive label) The addition amount of the curing agent to be added to the pressure-sensitive adhesive was 2 parts by weight based on 200 parts by weight of the pressure-sensitive adhesive, and the mixture was stirred, and the coated amount of the pressure-sensitive adhesive after drying was 20 g / m ^2. An adhesive label was produced in the same manner as in Example 1 except that the adhesive was applied as described above.

Example 4 (Polymerization of pressure-sensitive adhesive) The pressure-sensitive adhesive was emulsion-polymerized in the same manner as in Example 1 except that the main component contained in the pressure-sensitive adhesive was 98 parts by weight of 2-ethylhexyl acrylate and 1 part by weight of acrylic acid. . (Production of an adhesive label) An adhesive label was produced in the same manner as in Example 3.

Example 5 (Polymerization of pressure-sensitive adhesive) The pressure-sensitive adhesive was emulsion-polymerized in the same manner as in Example 1 except that the main ingredient contained in the pressure-sensitive adhesive was 93 parts by weight of 2-ethylhexyl acrylate and 1 part by weight of acrylic acid. Then, 5 parts by weight of dioctyl phthalic acid was added as a plasticizer to the pressure-sensitive adhesive, followed by stirring to obtain a pressure-sensitive adhesive. (Production of an adhesive label) An adhesive label was produced in the same manner as in Example 3.

Example 6 (Polymerization of pressure-sensitive adhesive) In Example 5, instead of 5 parts by weight of dioctyl phthalic acid, a naphthenic process oil (trade name: Shellflex 371JY, manufactured by Shell Japan KK) was used as a plasticizer. Example 5 except that parts by weight were used.
An adhesive was obtained in the same manner as described above. (Production of an adhesive label) An adhesive label was produced in the same manner as in Example 3.

Example 7 (Polymerization of PSA) The PSA was prepared in the same manner as in Example 1 except that the main components contained in the PSA were 80 parts by weight of 2-ethylhexyl acrylate and 1 part by weight of acrylic acid. Emulsion polymerization, 18 parts by weight of a naphthenic process oil (trade name: Shellflex 371JY, manufactured by Shell Japan Co., Ltd.) as a plasticizer were added to this adhesive, followed by stirring in the same manner as in Example 5 except for stirring. I got (Production of an adhesive label) An adhesive label was produced in the same manner as in Example 3.

Comparative Example 1 (Polymerization of pressure-sensitive adhesive) The pressure-sensitive adhesive was emulsion-polymerized in the same manner as in Example 1 except that the main components contained in the pressure-sensitive adhesive were 90 parts by weight of isononyl acrylate and 1 part by weight of acrylic acid. Then, a silicone oil (trade name: BY24-71) is added to the adhesive.
5, Toray Dow Corning Silicone Co., Ltd.)
A pressure-sensitive adhesive was obtained in the same manner as in Example 5 except that the parts by weight were added and stirred. (Production of an adhesive label) An adhesive label was produced in the same manner as in Example 3.

Comparative Example 2 (Polymerization of pressure-sensitive adhesive) Example 1 was repeated except that the main ingredients contained in the pressure-sensitive adhesive were 63 parts by weight of 2-ethylhexyl acrylate, 35 parts by weight of butyl acrylate, and 1 part by weight of acrylic acid.
The pressure-sensitive adhesive was emulsion-polymerized by the above method. (Production of an adhesive label) An adhesive label was produced in the same manner as in Example 3.

Comparative Example 3 (Polymerization of pressure-sensitive adhesive) Example 1 was repeated except that the main ingredients contained in the pressure-sensitive adhesive were 62 parts by weight of 2-ethylhexyl acrylate, 35 parts by weight of butyl acrylate and 2 parts by weight of acrylic acid.
The adhesive was emulsion-polymerized in the same manner as described above. (Production of pressure-sensitive adhesive label) A pressure-sensitive adhesive label was produced in the same manner as in Example 3 except that 2 parts by weight of the curing agent to be added to the pressure-sensitive adhesive was added to 200 parts by weight of the pressure-sensitive adhesive and stirring was performed.

Comparative Example 4 (Polymerization of pressure-sensitive adhesive) The pressure-sensitive adhesive was emulsion-polymerized by the method of Example 1 except that the main component contained in the pressure-sensitive adhesive was 75 parts by weight of 2-ethylhexyl acrylate and 1 part by weight of acrylic acid. . An adhesive was obtained in the same manner as in Example 5, except that 23 parts by weight of dioctyl phthalic acid was added to the adhesive and stirred. (Production of an adhesive label) An adhesive label was produced in the same manner as in Example 3.

"Evaluation Method" The pressure-sensitive adhesive labels obtained in the above Examples and Comparative Examples were evaluated by the following methods, and the results are shown in Table 1.

[Logarithmic Decay Rate Using Rigid Pendulum Type Physical Property Tester] The logarithmic decay rate of the pressure-sensitive adhesive layer surface of the pressure-sensitive adhesive label was measured under the following conditions. _Δmax ) and the temperature showing the maximum value were determined. Further, logarithmic decrements at 0 ° C. and 40 ° C. (Δ ₀ and Δ ₄₀ ) were obtained, and a value of Δ ₀ / Δ ₄₀ was calculated. (Measurement conditions) Measuring device: Rigid pendulum type physical property tester (RPT-α10
0, manufactured by Tohoku Denshi Sangyo Co., Ltd.) Frame type: FRB-20 Frame weight: 47.3 g Measurement section shape: knife-shaped edge, RBE-06 Inertia ratio: 2410 gcm Measurement temperature: -120 to 150 ° C Heating rate: 5 ° C / min Measurement interval: 10 seconds

[Measurement of DMA type viscoelasticity] A pressure-sensitive adhesive used for the pressure-sensitive adhesive label was previously applied to the release sheet in the same manner as in the production of the pressure-sensitive adhesive label, dried, and then 0.3 cm × 1.5 c
Two adhesives having a size of mx 2.0 cm are prepared and set in a shearing jig. The pressure-sensitive adhesive was measured under the following conditions.
The dynamic shear modulus of the pressure-sensitive adhesive at 2 ° C. was determined. Similarly, the dynamic shear modulus at 0 ° C. and 40 ° C. (G ′ ₀ and G ′
₄₀ ) was calculated, and G ′ ₀ / G ′ ₄₀ was calculated. (Measurement conditions) Measuring device: DMA child type viscoelasticity measuring device (Leo Vibron DDV-01 / 25FP, manufactured by Orientec) Frequency: 1 Hz Measurement temperature: -120 to 150 ° C. Temperature rising rate: 3 ° C./min

[Removability] As adherends, high-quality paper (trade name: OK Prince 64 g / m ² , manufactured by Oji Paper Co., Ltd.) and a SUS plate were used. The SUS plate is JI
The treatment was performed according to the method for polishing a SUS plate in the adhesive strength measurement method of SZ-0237. 100mm long adhesive label
X 25 mm in width, the adhesive surface of the adhesive label is affixed to the adherend, and reciprocated once at a speed of 300 mm / min with a 2 kg pressure roller according to the adhesive strength measurement method of JIS-Z-0237. After 30 minutes from the pressure bonding, the pressure-sensitive adhesive label was set to 0.
180 ° peeling is performed at a speed of 3 m / min and 60 m / min. At this time, the adhesive label was visually evaluated on a four-point scale to determine whether the adhesive label was cohesively fractured, the substrate was destroyed, or was detached cleanly without being directed to the fiber of the high quality paper as the adherend. (Evaluation item) ：: The adhesive label is peeled off from the adherend. ：: The adhesive label is peeled off from the adherend, although the peel resistance from the adherend is large. Δ: A very small amount of pressure-sensitive adhesive adhered to the adherend; ×: Adhesive adhered to the adherend, or fibrous waste on the adherend. Or the base material of the adhesive label is broken.

(Comprehensive Evaluation of Removability) Fine paper, SUS
In the evaluation results of the re-peeling performance with respect to the plate, ◎ indicates 4 points, and ○ indicates 3 points.
The points, Δ were 2 points, and × were 0 points, the measurement results of each adherend were totaled for each pressure-sensitive adhesive label, and the points when averaged were classified into the following evaluation items, which were regarded as comprehensive evaluation results as a removable adhesive label. . ◎: 3.5 or more and 4.0 or less ：: 2.5 or more and less than 3.5 Δ: 1.5 or more and less than 2.5 ×: less than 1.5

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[Table 1]

As is evident from Table 1, in each of the examples, it is found that the adhesive label is excellent as an adhesive label that can be attached to a high-quality paper or a SUS plate and then peeled off. On the other hand, it can be seen that the removability at a peeling speed of 0.3 m / min to 60 m / min after adhering to high quality paper or a SUS plate is poor, and is not suitable as a removable adhesive label.

Claims (4)

[Claims] 1. A pressure-sensitive adhesive label having a pressure-sensitive adhesive layer on one side of a surface substrate, wherein the pressure-sensitive adhesive layer has a logarithmic decrement of -100 to -60 ° C. using a rigid pendulum type physical property tester. Value, the maximum value is 0.5 or more, and 0
A removable pressure-sensitive adhesive label wherein the value of the logarithmic decay rate at 40 ° C. (Δ ₀ ) and the value of the logarithmic decay rate at 40 ° C. (Δ ₄₀ ) satisfy the following formulas (1) to (3). 0.70 ≦ Δ ₄₀ / Δ ₀ ≦ 3.00 (1) Δ ₄₀ ≦ 0.30 (2) Δ ₀ ≦ 0.30 (3) 2. The dynamic shear modulus of the pressure-sensitive adhesive at a frequency of 1 Hz and a temperature of 22 ° C. measured by a DMA (Dynamic Analyzer) is 1.0 × 10 ^{5 to} 1.0 × 10 ⁸ (dy
ne / cm ² ), and 0 ° C. and dynamic shear modulus (G ′ ₀ )
When removable adhesive label according to claim 1, wherein the dynamic shear modulus (G _'40) is a pressure-sensitive adhesive satisfying the expression (4) below at 40 ° C.. 0.7 ≦ G ′ ₄₀ / G ′ ₀ ≦ 5.0 (4) 3. The pressure-sensitive adhesive layer according to claim 1, wherein isononyl acrylate and / or 2-ethylhexyl acrylate is 70 to 99.
3. The removable adhesive label according to claim 1, which is a layer formed by applying and drying an acrylic emulsion containing 9% by weight. 4. The pressure-sensitive adhesive layer has a glass transition temperature of -70 to
4. The removable adhesive label according to claim 1, which contains 5 to 20% by weight of a plasticizer component at +10 [deg.] C.