JP2000191996A - Removal of acrylic pressure-sensitive adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely remove the adhesive remaining on the support by forming a pressure-sensitive adhesive layer mainly containing a specific acrylic copolymer and sticking the adhesive layer on the supporter to the adhesive-remaining site of the acrylic pressure-sensitive adhesive so that the adhesive layer may come inside and then peeling them. SOLUTION: A pressure-sensitive adhesive layer mainly comprising a copolymer of 59-94 wt.% of an acrylic monomer of the formula: CH2=C(R1)COOR2 (R1 is H or methyl; R2 is a 4-14C alkyl), 5-40 wt.% of an N-substituted-(meth) acrylamide represented by the formula: CH2=C(R3)CONR4R5 (R3 is H or methyl; R4 is H or a 4-14C alkyl, R5 is an alkyl or an organic group that links with R4 and N to form a heterocyclic ring), and 1-10 wt.% of a monomer bearing an acidic group, for example, acrylic acid is formed on the supporter to provide the sheet for removing adhesive remaining. The adhesive layer of the adhesive- removing sheet is stuck to the adhesive-remaining part on the substrate, then the applied adhesive sheet is peeled off and the remaining adhesive is completely removed thereby.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing an acrylic pressure-sensitive adhesive remaining on an adherend.

[0002]

2. Description of the Related Art In the home appliance / OA equipment, automobile industry, etc., a conventional liquid adhesive has been used for the purpose of simplifying work and improving safety and health when attaching decorative labels / stickers and fixing parts. Adhesive treatment using pressure-sensitive adhesive tape has been established, and among them, acrylic pressure-sensitive adhesive tape is widely used.

[0003] In recent years, in the above-mentioned industry, from the viewpoints of resource destruction and environmental pollution, recycling and reworking of parts has been required, and accordingly, when peeling off a pressure-sensitive adhesive tape for bonding and fixing, an adhesive is required. However, there is a problem that some of them remain on the equipment. This glue residue occurs not only at the time of the above-mentioned recycling but also attributable to a simple mistake in the attaching operation.

If an adhesive residue is left on an adherend such as a machine device, the appearance and performance are impaired, and it is necessary to remove it. Conventionally, methods for removing such adhesive residue include a method of swelling and dissolving the adhesive by treating it with an organic solvent and wiping it off, and a method of physically removing the adhesive using a mechanical tool such as a cutter or a grinder. Had been.

[0005]

However, the method using an organic solvent has safety and health and environmental problems, and the physical removal method has a problem that a great deal of labor and time are required for the operation. . Accordingly, it is an object of the present invention to provide a method for reliably and easily removing adhesive residue on an adherend without causing safety and health or environmental problems.

[0006]

To achieve the above object, the present inventors first use another commonly used acrylic or rubber pressure-sensitive adhesive tape as a tape for removing adhesive residue. Then, a method was studied in which the tape and the adhesive in the adhesive remaining portion were integrally peeled and removed by attaching the tape to the adhesive remaining portion of the adherend. However, in this method, sufficient adhesiveness was not obtained between the tape and the remaining adhesive portion, and effective removal could not be expected.

[0007] Therefore, as a result of further study on the above-described tape peeling removal method, most of the adhesive in the remaining adhesive portion is composed of an acrylic pressure-sensitive adhesive, and this adhesive has an adhesive property. Focusing on the fact that acidic groups derived from monomers are usually introduced from the point of, the pressure-sensitive adhesive layer as a paste residue removal tape suitable for removing such an adhesive, When composed of the same acrylic pressure-sensitive adhesive as the adhesive in the adhesive residue, and a pressure-sensitive adhesive having a -CON <bond, which has a strong interaction with the acidic group of the adhesive in the adhesive residue. However, the adhesiveness between the tape and the adhesive residue is improved, and the effect of removing the adhesive by the tape peeling is enhanced, which is different from using conventional organic solvents and mechanical tools. Ensure that safety, health and environmental issues do not occur. It was divide that you can easily remove the adhesive residue.

The present invention has been completed based on the above findings. That is, the present invention relates to the following: a) the adhesive remaining portion made of the acrylic pressure-sensitive adhesive remaining on the adherend;
General formula (1): CH ₂ ＣC (R ¹ ) COOR ² (wherein,
R ¹ is hydrogen or a methyl group, and R ² is an alkyl group having 4 to 14 carbon atoms).
And b) general formula (2): CH ₂ ＣC
(R ³ ) CONR ⁴ R ⁵ (wherein, R ³ is hydrogen or a methyl group, R ⁴ is hydrogen or an alkyl group, R ⁵ is an alkyl group, or is bonded to R ⁴ and complexed with this and an N atom. (Meth) acrylamide represented by the formula (1) which is an organic group constituting a ring):
A sheet for removing adhesive residue, in which a pressure-sensitive adhesive layer mainly composed of 10% by weight of a copolymer is provided on a support, is attached with the pressure-sensitive adhesive layer inside. The present invention relates to a method for removing an acrylic pressure-sensitive adhesive, wherein the sheet and the acrylic pressure-sensitive adhesive in the adhesive remaining portion are integrally peeled off.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the sheets for removing adhesive residue used in the present invention, the support has an interlayer strength between the adhesive and the pressure-sensitive adhesive layer. The type is not particularly limited as long as it is greater than the interlayer strength between the system pressure-sensitive adhesive and the adherend and does not break or break due to an external force applied at the time of peeling. In order to increase the interlaminar strength between the pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer, those subjected to an appropriate surface treatment such as a corona treatment, an undercoat treatment, and a spatter treatment can also be preferably used.

Examples of the material of the support include polyethylene, stretched polypropylene, polyester, polyvinyl chloride, polyvinylidene chloride, polyimide, nylon, moisture-proof cellophane, metal foil, and metal-deposited film. A foam may be used so as to follow and adhere to the unevenness of the adhesive remaining portion. The thickness of the support may be appropriately set in consideration of strength, workability, and the like, and is not particularly limited.If the thickness is too large, the ability to follow the unevenness of the adhesive remaining portion is deteriorated, and if the thickness is too small, the tensile strength is reduced. 10 ~ 500μ usually
m, preferably 20 to 250 μm.

In the sheet for removing adhesive residue used in the present invention, the pressure-sensitive adhesive layer comprises a) a compound represented by the following general formula (1): CH ₂
ＣC (R ¹ ) COOR ² (wherein R ¹ is hydrogen or a methyl group, and R ² is an alkyl group having 4 to 14 carbon atoms)
59 to 94% by weight of an acrylic monomer represented by the formula: b)
General formula (2): CH ₂ ＣC (R ³ ) CONR ⁴ R ⁵ (where R ³ is hydrogen or a methyl group, R ⁴ is hydrogen or an alkyl group, R ⁵ is an alkyl group, or R ⁴ (Meth) acrylamide represented by 5 to 40% by weight;
c) A pressure-sensitive adhesive mainly composed of a copolymer of 1 to 10% by weight of a monomer containing an acidic group.

The acrylic monomer of component a is such that R ² in the general formula (1) is a butyl group, an isobutyl group, an isoamyl group, a hexyl group, a heptyl group, a 2-ethylhexyl group,
It is an alkyl ester of acrylic acid or methacrylic acid comprising an alkyl group having 4 to 14 carbon atoms, such as an isooctyl group, an isononyl group, and an isodecyl group. When the number of carbon atoms of R ² is less than 4, the wettability of the pressure-sensitive adhesive is lowered and the initial adhesiveness is deteriorated, and when it exceeds 14, the adhesive strength is poor. One or more acrylic monomers of the component a are used in the range of 59 to 94% by weight of the whole monomers. If the content is less than 59% by weight, it is difficult to exert the performance as an acrylic pressure-sensitive adhesive. If the content exceeds 94% by weight, the (meth) acrylamide of the component b is insufficient, and the remaining adhesive portion is less than the acrylic pressure-sensitive adhesive. Adhesive performance becomes insufficient.

The (meth) acrylamide of the component b includes non-cyclic (meth) acrylamides such as N-monosubstituted (meth) acrylamide and N, N-disubstituted (meth) acrylamide represented by the general formula (2). Acrylamide and cyclic (meth) acrylamide are included. For example, N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-isopropyl (meth) acrylamide,
N, N-diethyl (meth) acrylamide, N, N-dibutyl (meth) acrylamide, N- (meth) acryloylmorpholine, N- (meth) acryloylpyrrolidone, N- (meth) acryloylpiperidine, N- (meth) acryloyl Pyrrolidine, N- (meth) acryloyl-4-piperidone and the like can be mentioned. One or more of (b) component (meth) acrylamide is used in an amount of 5 to 40% by weight, preferably 10 to 35% by weight of the whole monomer. If it is less than 5% by weight, the effect of the interaction with the adhesive residue is poor. If it exceeds 40% by weight, the elasticity at room temperature is increased, and the adhesive remaining portion has poor followability to irregularities. Also in this case, the adhesive performance of the adhesive remaining portion to the acrylic pressure-sensitive adhesive becomes insufficient.

Examples of the monomer containing an acidic group as the component (c) include monomers containing a carboxyl group such as acrylic acid, methacrylic acid, itaconic acid and crotonic acid, and 2-hydroxyethylacryloyl phosphate. -Monophosphate-containing monomers such as -hydroxypropylacryloyl phosphate are used. One or more of the monomers of the component c are used in an amount of 1 to 10% by weight, preferably 2 to 8% by weight of the whole monomer. When the amount is less than 1% by weight, the cohesive force of the pressure-sensitive adhesive decreases, and when the amount exceeds 10% by weight, the ability to follow the unevenness of the remaining adhesive portion is reduced. It is difficult to develop adhesive properties.

The copolymer may be prepared by modifying the above monomer mixture of the three components a to c with a modifying monomer (usually 30% by weight or less of the whole monomer) which can be copolymerized with these monomers if necessary. ), Together with conventional methods such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization.
Obtainable. When using the bulk polymerization method, it is preferable to employ a polymerization method using ultraviolet irradiation. Upon copolymerization, organic peroxides such as benzoyl peroxide, lauroyl peroxide, cumene oxide, 2,
Azo compounds such as 2'-azobisisobutyronitrile and 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-dimethoxy-2-phenylacetophenone, 2,2 ' -Thermal polymerization initiators and photopolymerization such as acetophenone compounds such as diethoxyacetophenone, benzoin ether compounds such as benzoin ethyl ether and benzoin isopropyl ether, and benzophenone compounds such as benzophenone and benzoyl benzoic acid. An initiator is used.

The pressure-sensitive adhesive layer contains such a copolymer as a main component, and usually contains an appropriate crosslinking agent, and is subjected to a crosslinking treatment so as to have excellent cohesive strength. As a crosslinking agent,
Known crosslinking agents such as isocyanate crosslinking agents, epoxy crosslinking agents, melamine resin crosslinking agents, metal salt crosslinking agents, metal chelate crosslinking agents, amino resin crosslinking agents, and peroxide crosslinking agents. Can be used. Among these,
Isocyanate-based crosslinking agents and epoxy-based crosslinking agents are particularly preferably used.

The isocyanate-based crosslinking agent includes aliphatic polyisocyanates such as ethylene diisocyanate, butylene diisocyanate, and hexamethylene diisocyanate.
Alicyclic polyisocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; 2,4-tolylene diisocyanate; 4,4 ' Aromatic polyisocyanates such as diphenylmethane diisocyanate and xylylene diisocyanate, and tolylene diisocyanate adduct of trimethylolpropane. Examples of the epoxy crosslinking agent include polyethylene glycol glycidyl ether, diglycidyl ether, and trimethylolpropane glycidyl ether.

In addition, an internal crosslinking agent may be included in the copolymerization in place of the above-mentioned crosslinking agent to improve the cohesion. Examples of the internal crosslinking agent include trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, 1,2-ethylene glycol di (meth) acrylate, and 1,6-hexanediol Polyfunctional (meth) acrylates such as (meth) acrylate and 1,12-dodecandiodiol (meth) acrylate are used.

In the pressure-sensitive adhesive layer, in addition to the above components, if necessary, an acrylic pressure-sensitive adhesive such as a tackifier resin, an antioxidant, an ultraviolet absorber, a coloring agent, a filler, an antistatic agent, etc. Various commonly used additives may be included. These additives and the above-mentioned cross-linking agents and the like are used in usual amounts according to the types.

The adhesive residue removing sheet used in the present invention is formed in a sheet-like or tape-like form by providing the above-mentioned specific pressure-sensitive adhesive layer on one side of the support. Things.
The pressure-sensitive adhesive layer may be provided by directly applying the pressure-sensitive adhesive layer on the support or by transferring the pressure-sensitive adhesive layer provided on the release paper onto the support. In order to increase the interlayer strength between the support and the pressure-sensitive adhesive layer, it is more preferable to apply directly to the support. The thickness of the pressure-sensitive adhesive layer may be appropriately set according to the thickness of the acrylic pressure-sensitive adhesive in the adhesive residue, and is not particularly limited, but is usually preferably 10 to 100 μm.
If the thickness of the pressure-sensitive adhesive layer is too thin, the ability to follow the unevenness of the remaining adhesive portion will be poor, and if it is too thick, cohesive failure of the adhesive layer will easily occur.

Such adhesive residue removing sheets have an adhesive property such that they can be easily attached to an adherend having an adhesive residue portion and can be peeled off without feeling large resistance. Adhesion measured according to -0237 is 100 to 2,000 g / 25 mm width, especially 200 to
It should be in the range of 1,500 g / 25 mm width. Such adhesiveness can be easily set by appropriately selecting the monomer composition of the copolymer constituting the pressure-sensitive adhesive layer, the type and amount of the additive, and the like.

The present invention is characterized in that the adhesive residue made of the acrylic pressure-sensitive adhesive remaining on the adherend is peeled off by using such adhesive residue removing sheets. An example of the above-mentioned adhesive residue is, when the acrylic pressure-sensitive adhesive tape for bonding and fixing is peeled off in the home appliance / OA equipment, the automobile industry, etc. due to recycling of parts, etc. When the anti-reflection sheet using acrylic pressure-sensitive adhesive is stuck to the surface of the glass plate when the parts remain, the above-mentioned anti-reflection sheet is peeled off due to a work error due to misalignment or inclusion of bubbles. At this time, a case where a part of the adhesive remains on the surface of the glass plate is exemplified.

The method of peeling and removing is as follows. First, a sheet for removing the adhesive residue is adhered to the adhesive residue portion made of the acrylic pressure-sensitive adhesive remaining on the adherend with the pressure-sensitive adhesive layer inside. wear. At that time, cut the above-mentioned sheets according to the size of the remaining glue, press it by hand crimping or hand rolling to completely cover the remaining glue, and adhere to the unevenness of the remaining glue Let it do. Next, if necessary, the sheet is left in this state for several minutes, and when the sheet is peeled off, the acrylic pressure-sensitive adhesive remaining in the glue is peeled off integrally with the sheet. The peeling and removal is not limited to manual work, and the sticking and peeling operations may be continuously performed using an appropriate device.

In the above-mentioned peeling and removing, the copolymer constituting the pressure-sensitive adhesive layer of the sheet for removing the adhesive residue is a monomer N
Since -CON <bond derived from substituted (meth) acrylamide has a bond, when this is brought into close contact with the adhesive residue, the acid group contained in the acrylic pressure-sensitive adhesive in the adhesive residue and the above Due to the interaction with -CON <bond, a strong interfacial strength is obtained, and the adhesiveness between the sheets and the adhesive residue is remarkably enhanced. as a result,
By peeling off the sheets, the acrylic pressure-sensitive adhesive remaining in the glue is almost completely removed. As described above, according to the peeling and removing method of the present invention, unlike using a conventional organic solvent or a mechanical tool, there is no problem in terms of safety and hygiene and the environment, and the adhesive residue can be reliably and easily removed.

[0025]

Next, an embodiment of the present invention will be described in more detail. However, the present invention is not limited by these examples. In the following, “parts” means “parts by weight”.

Example 1 Isooctyl acrylate 80 was placed in a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer, an ultraviolet irradiation device, and a stirring device.
Parts, acryloyl morpholine 15 parts, acrylic acid 5 parts,
0.07 parts of 2,2-dimethoxy-2-phenylacetone phenone was added as a photopolymerization initiator and subjected to photopolymerization to obtain a polymer / monomer mixture having a polymerization rate of 15% by weight. Further, with respect to 100 parts of the solid content of this mixture,
0.1 parts of propane triacrylate was added to obtain a syrup.

This shirop is used as a support and has a thickness of 40
It is applied on stretched polypropylene subjected to a corona treatment of μm, and irradiated with ultraviolet rays of 900 mj / cm ² by a high-pressure mercury lamp having a light intensity of 5 mW / cm ² in a nitrogen gas atmosphere to obtain a light-sensitive material having a thickness of 50 μm. An adhesive residue removal sheet having a pressure-sensitive adhesive layer was prepared.

Example 2 A sheet for removing adhesive residue was prepared in the same manner as in Example 1 except that a polyester film having a thickness of 25 μm was used as a support.

Example 3 A syrup was obtained in the same manner as in Example 1 except that the monomer composition was changed to 70 parts of isooctyl acrylate, 25 parts of acryloylmorpholine, and 5 parts of acrylic acid. In the same manner as in Example 1, an adhesive residue removal sheet was produced.

Example 4 The monomer composition was changed to 65 parts of isooctyl acrylate,
A syrup was obtained in the same manner as in Example 1 except that N-diethylacrylamide was changed to 30 parts and acrylic acid was changed to 5 parts. Using this, a sheet for removing adhesive residue was prepared in the same manner as in Example 1. .

Example 5 A reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer and a stirrer was charged with 90 parts of 2-ethylhexyl acrylate, 8 parts of acryloylmorpholine, 2 parts of acrylic acid, and 2 parts of a polymerization initiator. 0.14 parts of 2,2'-azobisisobutyronitrile and 100 parts of a mixture thereof were mixed with 100 parts of ethyl acetate.
Then, the mixture was reacted at 60 ° C. for 12 hours to obtain a polymer solution. To 100 parts of the solid content of this solution, 1 part of a tolylene diisocyanate adduct of trimethylolpropane [“Coronate L” manufactured by Nippon Polyurethane Co., Ltd.] was added, and a pressure-sensitive adhesive solution was added. And This was used as a support, applied to a 40 μm thick corona-treated stretched polypropylene, and dried to prepare a sheet for removing adhesive residue having a 50 μm thick pressure-sensitive adhesive layer.

Comparative Example 1 The monomer composition was changed to 2-ethylhexyl acrylate 95
Parts, and 5 parts of acrylic acid, except that a pressure-sensitive adhesive solution was obtained in the same manner as in Example 5, and this was used to prepare an adhesive residue removal sheet in the same manner as in Example 5. .

Comparative Example 2 A sheet for removing adhesive residue was prepared in the same manner as in Comparative Example 1 except that a polyester film having a thickness of 25 μm was used as a support.

Comparative Example 3 A syrup was obtained in the same manner as in Example 1, except that the monomer composition was changed to 90 parts of isooctyl acrylate, 2 parts of acryloylmorpholine, and 8 parts of acrylic acid. ,
In the same manner as in Example 1, a sheet for removing adhesive residue was prepared.

Comparative Example 4 The monomer composition was changed to 50 parts of isooctyl acrylate,
A syrup was obtained in the same manner as in Example 1 except that N-diethylacrylamide was changed to 45 parts and acrylic acid was changed to 5 parts, and a sheet for removing the adhesive residue was prepared in the same manner as in Example 1 using this. .

Comparative Example 5 A commercially available packaging sheet (a sheet in which a natural rubber-based pressure-sensitive adhesive layer having a thickness of 30 μm was provided on one side of an expanded polypropylene having a thickness of 40 μm) was glued. A sheet for removing the remaining was used.

Using the adhesive residue removal sheets of Examples 1 to 5 and Comparative Examples 1 to 5, the following method was used.
A test for removing the adhesive residue made of the acrylic pressure-sensitive adhesive remaining on the adherend (glass plate) was performed.

<Removal Test of Acrylic Pressure-Sensitive Adhesive> The pressure-sensitive adhesive solution obtained in Comparative Example 1 (a solution of the acrylic pressure-sensitive adhesive having only a carboxyl group as an acidic group in the copolymer) was used. This was used and applied on the release-treated surface of a 25 μm-thick polyester separator with one surface released with a silicone-based release agent so that the thickness after drying was 50 μm, followed by drying. Thus, an acrylic pressure-sensitive adhesive tape was produced.
This tape was cut into a size of 15 mm × 90 mm, and pressed by a method of reciprocating a 2 kg roller on a glass plate.
After standing for 24 hours in a 5% RH atmosphere, the polyester separator was peeled off, and a 50 μm thick plate was placed on a glass plate.
m of the acrylic pressure-sensitive adhesive was left as adhesive residue.

Next, a sheet for removing the adhesive residue is set to 20 mm × 1.
The glass plate was cut into a size of 00 mm, and was pressed by a method of reciprocating a 2 kg roller so as to cover the entire remaining adhesive portion on the glass plate. Thereafter, the film was immediately peeled off at an angle of 180 ° using a universal tensile tester at a tensile speed of 50 mm / min. After peeling in this manner, the state of removal of the acrylic pressure-sensitive adhesive on the glass plate was observed, and the removability of the adhesive was evaluated. These results were as shown in Table 1.

[0040]

As is clear from the results shown in Table 1 above, the use of the adhesive residue removing sheets of Examples 1 to 5 of the present invention ensures that the adhesive residue composed of the acrylic pressure-sensitive adhesive is reliably removed. It can be seen that it can be removed. On the contrary,
In the case of using the adhesive residue removal sheets of Comparative Examples 1 to 5,
The glue residue cannot be removed.

[0042]

As described above, according to the present invention, a pressure-sensitive adhesive layer mainly composed of a specific copolymer containing N-substituted (meth) acrylamide as one of the copolymer components is provided on a support. By using the adhesive residue removal sheet provided, the adhesive residue made of the acrylic pressure-sensitive adhesive remaining on the adherend can be reliably and safely produced without causing health and safety or environmental problems. A simple removal method can be provided.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Go Yamanaka 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Takahira, etc. 1-1-2 Shimohozumi, Ibaraki-shi, Osaka F-term in Nitto Denko Corporation (reference) 4J004 AA10 AB01 CA02 CA04 CA05 CA06 CA08 CC02 CD01 FA01 FA08 FA10 4J040 DF041 DF042 DF052 GA07 GA17 GA22 JA09 JB09 LA06 MA10 NA22 PA42

Claims (1)

[Claims] 1. An adhesive pressure-sensitive adhesive remaining on an adherend, comprising: a) a general formula (1): CH ₂ =
An acrylic monomer represented by C (R ¹ ) COOR ² (wherein R ¹ is hydrogen or a methyl group, and R ² is an alkyl group having 4 to 14 carbon atoms); , B) general formula (2): CH ₂ ＣC (R ³ ) CONR ⁴ R ⁵ (wherein R ³ is hydrogen or methyl, R ⁴ is hydrogen or alkyl, R ⁵ is alkyl, or in combination with 5 to 40% by weight represented by (meth) acrylamide with an organic group constituting a heterocyclic ring) in between this and N atoms as R ^4,
c) A sheet for removing adhesive residue, which is provided on a support with a pressure-sensitive adhesive layer mainly composed of a copolymer of 1 to 10% by weight of a monomer containing an acidic group, is subjected to the above-mentioned pressure-sensitive method. A method for removing an acrylic pressure-sensitive adhesive, characterized in that the sheet and the acrylic pressure-sensitive adhesive in the remaining portion of the adhesive are integrally peeled and removed, with the adhesive layer being applied inside.