JP3410160B2 - Biodegradable adhesive label - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pressure-sensitive adhesive label, and more particularly to a biodegradable pressure-sensitive adhesive label which is decomposed by microorganisms when buried in soil and disposed of and does not adversely affect the natural environment.

[0002]

BACKGROUND OF THE INVENTION Conventionally, an adhesive label body comprising an adhesive label main body in which an adhesive label base material and an adhesive layer are laminated and a release sheet in which a release agent layer is formed on a paper sheet, The pressure-sensitive adhesive label provided by adhering the pressure-sensitive adhesive layer of 1 to the release agent layer of the release sheet is widely used.

This type of adhesive label is used by peeling off the adhesive label body from the release sheet. By the way, a plastic base material has been mainly used as a base material of the adhesive label body as described above. Such conventional pressure-sensitive adhesive labels are processed by burning the pressure-sensitive adhesive label body and the release sheet after use or discarding them in the soil.

However, these processes have the following problems. (1) Problems when incinerating an adhesive label body When incinerating a label body containing a plastic base material, incineration of the plastic base material requires energy. In addition, carbon dioxide generated when incinerating the plastic substrate may cause global warming. Especially when the plastic substrate is vinyl chloride, hydrogen chloride gas is generated when the adhesive tape is incinerated, which causes acid rain.

(2) Problems in Disposing Adhesive Label Main Body in Soil In recent years, the number of cases in which an adhesive label main body after use is buried in the soil and disposed of has dramatically increased. It is difficult to secure. Also, the plastic material dumped in the soil is stable for a long period of time,
There is a risk of destroying the natural environment or the ecosystem in the soil.

Further, if the plastic base material is separated from the used adhesive label body and then reused,
Enormous cost is required for separate collection of plastic base materials,
It is inferior in marketability, and the quality of the plastic substrate is deteriorated.

[0007]

SUMMARY OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, and protects the natural environment even when the used adhesive label is discarded in the soil. It is an object of the present invention to provide an adhesive label that does not destroy and does not disturb the soil ecosystem.

[0008]

SUMMARY OF THE INVENTION A biodegradable pressure-sensitive adhesive label according to the present invention comprises a pressure-sensitive adhesive label substrate comprising a biodegradable polymer layer and a rosin.
And its derivatives, terpenes and their derivatives
Of one or more tackifying resins and natural rubber
It comprises a biodegradable pressure-sensitive adhesive label body in which a pressure-sensitive adhesive layer made of a mixture is laminated, and a release sheet in which a release agent layer is formed on a release sheet substrate made of paper and / or a non-biodegradable polymer. The biodegradable adhesive label body and the release sheet are laminated so that the adhesive layer of the biodegradable adhesive label body and the release agent layer of the release sheet are in contact with each other.

Of these, the pressure-sensitive adhesive label substrate may be composed of only the biodegradable polymer layer. The pressure-sensitive adhesive label substrate may be a laminate composed of a biodegradable polymer layer and a paper layer, and the pressure-sensitive adhesive layer may be formed on the paper layer. Further, this adhesive label substrate may have a metal thin film or a metal oxide thin film laminated in place of the paper layer.

On the other hand, the release sheet substrate may be composed of only the paper layer or may be composed of only the non-biodegradable polymer layer. The release sheet substrate may be a laminate of a paper layer and a non-biodegradable polymer layer,
It may be a laminate of non-biodegradable polymer layer / paper layer / non-biodegradable polymer layer.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The biodegradable pressure-sensitive adhesive label according to the present invention will be specifically described below. Specific examples of the biodegradable pressure-sensitive adhesive label according to the present invention are shown in FIGS.

The biodegradable adhesive label 10 shown in FIG. 1 is composed of a biodegradable adhesive label body 20 and a release sheet 30. Further, in the biodegradable pressure-sensitive adhesive label body 20, the pressure-sensitive adhesive layer 2 is laminated on one surface of the pressure-sensitive adhesive label base material 1 made of only the biodegradable polymer layer a.

Of these, any biodegradable polymer can be used for the biodegradable polymer layer a as long as it is formed of a biodegradable polymer. It is preferably formed from a polymer.

A) Linear polyester of 3-hydroxybutyric acid and 3-hydroxyvaleric acid (trade name: Biopol, manufactured by ICI UK) This linear polyester (Biopol) is Al
Obtained by sugar fermentation with caligenes Europhus.

B) Lactic acid-based biodegradable polymer (manufactured by Shimadzu Corporation) produced by ring-opening polymerization of lactide obtained by lactic acid fermentation of glucose, etc. c) Natural high levels of starch, polysaccharides, chitin, etc. A biodegradable polymer produced from a molecule [for example, pullulan (trade name, manufactured by Hayashibara Laboratory Co., Ltd.)] d) Biodegradable polycaprolactone obtained by ring-opening polymerization of ε-caprolactone e) Polyvinyl alcohol or a modified product thereof Biodegradable polymer (trade name Vitex, manufactured by Air Products and Chemicals, Inc.) f) Polyether, polyacrylic acid, ethylene / carbon monoxide copolymer, aliphatic polyester / polyamide copolymer, aliphatic polyester / polyolefin Copolymer, aliphatic polyester / aromatic polyester copolymer, aliphatic Biodegradable polymer such as re-ester / polyether copolymer g) Biodegradable polymer such as polylactic acid, polybutyric acid, polyglycolide or their derivatives h) Polymer alloy of starch and modified polyvinyl alcohol (trade name: Mataby) , Manufactured by Novamont, USA) etc.

I) Polymer alloy of starch and polyethylene (trade name: Polygrade II, manufactured by Ampacet; trade name: Polyclean, manufactured by Arcer Daniel Midland Co., USA) j) Composition of silane starch and polyethylene (trade name: Eco Star, manufactured by St. Lawrence Starch) k) Polymer alloy of polycaprolactone and polyethylene (trade name: Biomicron, manufactured by JSP; trade name: Tone, manufactured by Union Carbide, USA) Anyway, such a biodegradable polymer layer is used. When the biodegradable adhesive label body 20 as a base material is discarded in the soil, the biodegradable polymer layer a is decomposed into carbon dioxide and water by the microorganisms in the soil.

The thickness of the pressure-sensitive adhesive label substrate 1 composed only of the biodegradable polymer layer a as described above is usually 12 to 1.
It is 25 μm, preferably 25 to 100 μm.
Such an adhesive label substrate 1 is formed by film-forming a mixture of the above-mentioned biodegradable polymer, for example, starch and modified polyvinyl alcohol by an inflation method or a T-die casting method, and if necessary, stretching as a post-processing. It is processed and adjusted to a desired film thickness.

The pressure-sensitive adhesive layer 2 is formed on one surface of the pressure-sensitive adhesive label base material 1. As the pressure-sensitive adhesive that can form the pressure-sensitive adhesive layer 2, for example, rosin and its derivative (hydrogenation). Rosin, disproportionated rosin, polymerized rosin, rosin ester, etc.), and one or more selected from terpenes and their derivatives (α-pinene resin, β-pinene resin, dipentene resin and hydrogenated products thereof). An example of the pressure-sensitive adhesive is a mixture of a tackifying resin and natural rubber. Of these, the natural rubber may be solid or latex. In the adhesive, natural rubber 10
It is preferable to add 1 to 150 parts by weight of the tackifying resin to 0 parts by weight.

The pressure-sensitive adhesive as described above exhibits biodegradability and is therefore preferable in forming the pressure-sensitive adhesive layer 2 according to the present invention.
The biodegradable pressure-sensitive adhesive label body 20 including the biodegradable pressure-sensitive adhesive label substrate 1 and the biodegradable pressure-sensitive adhesive layer 2 may destroy the natural environment even if it is discarded in the soil. Absent.

As the pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive that has been widely used in the past can also be used. This acrylic adhesive is usually deteriorated and decomposed when it is discarded in the soil.

The adhesion amount of the pressure-sensitive adhesive layer 2 is usually 10 to 10.
100 g / m ² , preferably 20 to 50 g / m ^2.
Is. Such a pressure-sensitive adhesive layer 2 is obtained by, for example, applying a solution in which the above-mentioned pressure-sensitive adhesive is dissolved to one surface of the pressure-sensitive adhesive label substrate 1 and drying at a temperature of 50 to 120 ° C. .

As the solvent for the adhesive coating liquid as described above, for example, toluene, xylene, ethyl acetate or the like is used. On the other hand, the release sheet 30 is composed of the release sheet base material 3 and the release agent layer 4, and the release agent layer 4 is formed on one surface of the release sheet base material 3.

Of these, the release sheet base material 3 is formed only from the paper layer. Further, as the release agent capable of forming the release agent layer 4, shellac, natural wax, casein,
One or more kinds of release agents made of natural compounds such as starch, polyvinyl alcohol and its derivatives, and synthetic release agents such as silicone are used.

Some of the above-mentioned release agents made of natural compounds and synthetic release agents made of polyvinyl alcohol and its derivatives are biodegradable. In the present invention, it is preferable to use the release agent layer 4 formed of these biodegradable release agents. Thereby, even if the release sheet 30 is discarded in the soil, the natural environment will not be destroyed.

The thickness of the release agent layer 4 is usually 0.01
˜1 μm, preferably 0.03 to 0.1 μm. Such a release agent layer 4 can be obtained by applying the above-mentioned release agent to one surface of the release sheet base material 3 with a roll coater or the like.

Release sheet 30 obtained as described above
The pressure-sensitive adhesive layer 2 of the biodegradable pressure-sensitive adhesive label body 20 is adhered onto the release agent layer 4 to form the biodegradable pressure-sensitive adhesive label according to the present invention.

The adhesive label 10 shown in FIG. 2 is the same as the biodegradable adhesive label 10 of FIG. 1 except for the adhesive label base material 1 of the biodegradable adhesive label body 20. In the biodegradable pressure-sensitive adhesive label body 20 shown in FIG. 2, the pressure-sensitive adhesive label substrate 1 is composed of a laminate of a biodegradable polymer layer a and a paper layer b.

Of these, the biodegradable polymer layer a and its thickness are the same as those described above. The paper layer b is usually 50 to 150 g / m ² , preferably 60.
~ 100 g / m ² of paper is used.

Such biodegradable polymer layer a and paper layer b
The pressure-sensitive adhesive label substrate 1 composed of a laminated body of, for example, the biodegradable polymer layer a on the paper layer b is 10
It is obtained by a method such as laminating at a temperature of 0 to 300 ° C.

The biodegradable pressure-sensitive adhesive label 10 shown in FIG. 3 is also the same as the biodegradable pressure-sensitive adhesive label 10 of FIG. 1 except for the pressure-sensitive adhesive label substrate 1 of the biodegradable pressure-sensitive adhesive label body 20. However, in the biodegradable adhesive label body 20 shown in FIG. 3,
The adhesive label substrate 1 is composed of a biodegradable polymer layer a and a metal thin film c.
And a laminate. Further, instead of the metal thin film c, a metal oxide thin film such as silica may be formed.

Of these, the biodegradable polymer layer a and its thickness are the same as those described above. Further, as the metal thin film c, for example, a metal thin film of aluminum, brass, chrome or the like is used, and the film thickness of the metal thin film c is usually
50-1000 angstrom, preferably 100-
It is 300 angstroms.

The pressure-sensitive adhesive label substrate 1 composed of such a laminated body of the biodegradable polymer layer a and the metal thin film c is formed by, for example, vacuum deposition, sputtering, or ion plating method. It can be obtained by a method of forming a metal thin film such as aluminum on a. For example, when the metal thin film c is formed on the biodegradable polymer layer a by a vacuum deposition method, the degree of vacuum is 1 × 10 ⁻⁴ to 1 × 10.
Adjusted to ^-5 torr. The metal thin film c thus formed on the biodegradable polymer layer a is usually 1 × 10 5.
^-12 to 1 x 10 ^-14 cm ³ (STP) cm / cm ²
It has an oxygen permeability coefficient of sec · cmHg.

The pressure-sensitive adhesive label 10 shown in FIG. 4 is different from the biodegradable pressure-sensitive adhesive label 1 shown in FIG. 1 except that the release sheet substrate 3 of the release sheet 30 is formed of the non-biodegradable polymer layer d.
The same as 0.

The non-biodegradable polymer layer d is composed of a conventionally known non-biodegradable polymer such as polyvinyl chloride, polyvinylidene fluoride and polyethylene, and the film thickness thereof is the film thickness of the biodegradable polymer layer a. Is the same as.

The pressure-sensitive adhesive label according to the present invention is shown in FIGS.
In addition to the adhesive label shown in (1), for example, the release sheet base material of the release sheet is formed of a laminate of a paper layer and a non-biodegradable polymer layer, and the release sheet base material is non-biodegradable. Various embodiments are possible without departing from the scope of the present invention as set forth in the claims, including an adhesive label formed of a laminate of polymer layer / paper layer / non-biodegradable polymer layer. is there.

[0036]

As described above, according to the present invention, since the biodegradable polymer is used as the adhesive label base material, even if it is discarded in the soil after use, the natural environment is destroyed. , Does not significantly disturb the soil ecosystem.

The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0038]

EXAMPLE A biodegradable polymer layer having a thickness of 70 μm
A film composed of a copolymer of -hydroxybutyric acid and 3-hydroxysuccinic acid ("Biopol", ICI, UK
(Manufactured by Mfg. Co., Ltd.), aluminum was vapor-deposited on one side at a vacuum degree of 5 × 10 ⁻⁵ torr to form an aluminum thin film.

To this aluminum thin film, a toluene solution containing a mixture of natural rubber and a terpene resin as an adhesive at a concentration of 20% was applied by a comma coater to obtain an adhesion amount of 3
A pressure-sensitive adhesive layer of 0 g / m ² was formed to obtain a biodegradable pressure-sensitive adhesive label body.

Next, a 12 μm-thick polyethylene film (trade name: Shoflex L170, Showa Denko KK) is heated on both sides of a high-quality paper (manufactured by Lintec Co., Ltd.) having a basis weight of 80 g / m ² at a heating temperature of 300. By laminating with an extruder at 0 ° C., a release sheet substrate comprising a biodegradable polymer layer and a paper sheet was obtained.

A release agent layer was formed on the biodegradable polymer layer of the release sheet substrate using a silicone release agent (trade name SRX244, manufactured by Toray Silicone Co., Ltd.) to obtain a release sheet.

The pressure-sensitive adhesive layer of the main body of the biodegradable pressure-sensitive adhesive label and the release agent layer of the release sheet were laminated and adhered to each other to obtain the biodegradable pressure-sensitive adhesive label of Example 1. The biodegradable pressure-sensitive adhesive label thus obtained was cut into a width of 25 mm, and then the biodegradable pressure-sensitive adhesive label body was peeled from the release sheet so that the pressure-sensitive adhesive layer of the biodegradable pressure-sensitive adhesive label body was in contact with S.
The adhesive tape was adhered to the US304 surface, and then the adhesive tape was peeled from the SUS304 surface at a peeling rate of 300 mm / min and a peeling angle of 180 ° in 23 ° C 65% RH, and the adhesive strength of the biodegradable adhesive label was evaluated from the peeling strength at this time did.

The biodegradable pressure-sensitive adhesive label obtained by the above method was cut into a size of 100 mm × 100 mm, and the obtained sample was buried in soil having a depth of 10 cm for 1 month and 3 months.
After leaving it for a month, it was dug out, and the decomposition rate of the biodegradable adhesive label was evaluated by the following formula.

[0044]

[Equation 1]

The above results are shown in Table 1.

[0046]

[Comparative Example] An adhesive label was prepared in the same manner as in Example 1 except that a 75 μm thick polyester film (trade name Lumirror S-10, manufactured by Toray Industries, Inc.) was used as the adhesive label substrate. The adhesive force and the decomposition rate of the obtained adhesive label were evaluated.

The above results are shown in Table 1.

[0048]

[Table 1]

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a biodegradable pressure-sensitive adhesive label according to the present invention.

FIG. 2 is a schematic sectional view of a biodegradable adhesive label according to the present invention.

FIG. 3 is a schematic sectional view of a biodegradable adhesive label according to the present invention.

FIG. 4 is a schematic sectional view of a biodegradable adhesive label according to the present invention.

[Explanation of symbols]

10 ... Biodegradable adhesive label 20 ... Biodegradable adhesive label body 30 ... Release sheet 1 ... Adhesive label base material 2 ... Adhesive layer 3 ... Release sheet base material 4 ... Release agent layer a ... Biodegradable polymer layer b ... Paper layer c ... Metal thin film or metal oxide thin film d ... Non-degradable polymer layer

Continuation of the front page (56) References JP-A-5-57842 (JP, A) JP-A-6-190976 (JP, A) JP-A-5-329999 (JP, A) JP-A-5-84876 (JP , A) JP-A-2-222421 (JP, A) JP-A-57-90076 (JP, A) JP-A-2-64689 (JP, A) Actual development Sho-45-45145 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G09F 3/00 B32B 7/10 C09J 7/02 G09F 3/10

Claims (8)

(57) [Claims] 1. An adhesive label substrate comprising a biodegradable polymer layer , rosin and its derivative, terpene and its derivative.
One or more tackifying trees selected from derivatives
A biodegradable pressure-sensitive adhesive label main body obtained by laminating an adhesive layer made of a mixture of fat and natural rubber, and a release agent layer formed on a release sheet substrate made of paper and / or a non-biodegradable polymer. And a release sheet, wherein the biodegradable adhesive label body and the release sheet are laminated so that the adhesive layer of the biodegradable adhesive label body and the release agent layer of the release sheet are in contact with each other. Biodegradable adhesive label. 2. The biodegradable pressure-sensitive adhesive label according to claim 1, wherein the pressure-sensitive adhesive label substrate is composed only of a biodegradable polymer layer. 3. The adhesive label substrate is a laminate of a biodegradable polymer layer and a paper layer, and an adhesive layer is formed on the paper layer. The biodegradable adhesive label described. 4. The adhesive label substrate is a laminated sheet of a biodegradable polymer layer and a metal thin film or a metal oxide thin film, and an adhesive layer is formed on the metal thin film. The biodegradable adhesive label according to claim 1. 5. The biodegradable pressure-sensitive adhesive label according to claim 1, wherein the release sheet substrate comprises a paper layer only. 6. The biodegradable pressure-sensitive adhesive label according to claim 1, wherein the release sheet substrate comprises only a non-biodegradable polymer layer. 7. The release sheet substrate comprises a laminate of a paper layer / non-biodegradable polymer layer, and a release agent layer is formed on the non-biodegradable polymer layer. Item 5. A biodegradable adhesive label according to any one of items 1 to 4. 8. The biodegradation according to any one of claims 1 to 4, wherein the release sheet substrate comprises a laminate of a non-biodegradable polymer layer / paper layer / non-biodegradable polymer layer. Adhesive label.