JP2000191999A - Delayed adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a delayed adhesive that is non-adhesive, while it is stored, and develops the pressure-sensitive adhesion caused by breakage of the molecular chain, when it is used by adding a cross-linking compound to the starting monomer or the polymer therefrom. SOLUTION: To 100 pts.wt. of a starting monomer, for example, a (meth) acrylic alkyl ester bearing 2-14C alkyl group, for example, lauryl methacrylate or its polymer, are added 0.3-100 pts.wt., preferably 0.5-50 pts.wt., more preferably 0.8-30 pts.wt. of a crosslinking compound bearing a radically polymerizable unsaturated group, for example, an epoxy group, an isocyanate group or the like or a cross linkable compound bearing no radically polymerizable unsaturated group, for example, pentaerythritol or the like to obtain the objective delayed pressure-sensitive adhesive that manifests adhesion properties by the breakage of molecular chains with irradiation of electromagnetic waves or with electron beams. The delayed adhesion product is given by providing the layer of this pressure-sensitive adhesive on the base material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a delayed pressure-sensitive adhesive which is non-tacky during storage, but is used by developing tackiness when used.

[0002]

2. Description of the Related Art Conventional delay adhesives are described in "Adhesion Handbook" (No.
As described in the 12th edition, published by the Society of Polymer Publishing, 1980), it is non-adhesive at room temperature, but develops adhesiveness by heating, and its composition is thermoplastic resin and solid Based on plasticizer. Thermoplastic resin is a source of adhesive strength and adhesive strength. In addition, the solid plasticizer does not impart plasticity to the resin because it is a solid at room temperature, and melts by heating to swell or soften the resin. Works.

[0003] Such a method using a heat-sensitive delay adhesive has the advantage that it is environmentally friendly and requires less cost as compared with a normal adhesive product because a release paper is not required.

[0004]

However, in a pressure-sensitive adhesive product using such a heating-type delayed pressure-sensitive adhesive, various obstacles and problems due to its heat sensitivity appear.

[0005] That is, the above-mentioned solid plasticizers that can be generally used at present are limited, and crystalline compounds having a melting point of about 60 ° C to 80 ° C typified by dicyclohexyl phthalate are mainly used. The existing heat-sensitive retardation adhesive contains a large amount of such a solid plasticizer, and even under its melting point, depending on the storage conditions and composition, it softens and gives the resin plasticity, so that high temperatures such as in summer Under the conditions, tackiness appeared on the whole and there was a problem in terms of blocking resistance of the product. Therefore, in the case of a conventional delayed tack label or sheet product using such a heat-sensitive adhesive, an air conditioner is required in a storage warehouse or a transport vehicle.

The above-mentioned solid plasticizer must not be melted when a pressure-sensitive adhesive is applied to a substrate and dried by heating. That is, it must not be melted at the time of coating and drying, compatible with the thermoplastic resin which is the base of the adhesive, and should not be plasticized (developing the adhesiveness). It is necessary to plasticize the plastic resin. Conventional heat-sensitive delay adhesives have to be dried slowly with hot air of at most 40 to 50 ° C. for a long time for the above reason, and the coating efficiency is very poor. By the way, the usual adhesive depends on the base material,
Hot air of 80-120 ° C can be applied, and it can be dried efficiently.

[0007] As described above, the solid plasticizer is usually crystalline, and after the adhesive is applied to the substrate, these crystal particles appear on the surface, and the adhesive-coated surface is liable to be in a powder-blown state. Tends to occur. When this choking phenomenon occurs, for example, when cutting a roll-wound label material one by one or at the time of use, the powder scatters, contaminating the label surface or product, or entering the precision parts of the machine There was a problem of causing various troubles.

Further, even when the heat-sensitive delayed pressure-sensitive adhesive is heated during use to develop the pressure-sensitive adhesive, the pressure-sensitive adhesive does not last semipermanently, but the solid plasticizer gradually recrystallizes and becomes cloudy. At the same time, the resin loses tackiness with time and becomes brittle. Therefore, for example, the label cannot be used for a transparent label or the like, and when used as a label on a plastic adherend such as a bottle, a phenomenon that the label comes off due to the embrittled adhesive when the bottle is deformed appears. As described above, it cannot be used for a deformable product such as a transparent product or a squeeze bottle, and there is a great limitation in its use.

With respect to such heat-sensitive retardation adhesives, solid plasticizers, which are essential, have been improved, for example, by increasing the melting point. However, if the melting point is increased, the blocking resistance and coating properties will be reduced. Although better, the activation temperature is higher,
There is a contradiction that embrittlement due to crystallization is likely to occur. In any case, the above problems have not been fundamentally solved.

Further, it is necessary to use a large amount of expensive solid plasticizers, including those mentioned above, and the heat-sensitive delayed pressure-sensitive adhesive does not stand out from the conventional pressure-sensitive adhesive with release paper, and has become popular. The current situation is that it has not advanced much.

An object of the present invention is to provide a delay adhesive which has solved the above problems.

[0012]

DISCLOSURE OF THE INVENTION The present invention provides a delayed pressure-sensitive adhesive containing a polymer exhibiting tackiness by breaking a molecular chain, and a delayed pressure-sensitive adhesive product comprising a layer comprising the delayed pressure-sensitive adhesive provided on a substrate. And a delayed pressure-sensitive adhesive product comprising a substrate and a delayed pressure-sensitive adhesive layer containing a polymer provided on the substrate and exhibiting tackiness by cutting molecular chains, wherein the weight of the delayed pressure-sensitive adhesive layer is reduced. Provided is a method for attaching a delayed adhesive product which is applied to an adherend after the adhesive is developed by cutting a molecular chain of the united product.

More specifically, instead of using a conventional heating-based retardation adhesive, a method of applying an electromagnetic wave or an electron beam or the like to break the molecular chain of a non-tacky polymer to exhibit adhesiveness. Provided is an entirely new delayed adhesive, an adhesive product, and a method of applying the same.

[0014] The present invention provides a method in which a specific retardation adhesive layer having no tackiness is formed on a base material, and then a polymer in the layer is subjected to a specific treatment so that the retardation adhesive layer has an adhesive property. It is used as an adhesive product by expressing its properties.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The delayed pressure-sensitive adhesive of the present invention contains a polymer which develops tackiness by breaking a molecular chain (hereinafter sometimes referred to as the polymer of the present invention). The polymer of the present invention is non-adhesive or low-adhesive at the time of storage or the like, but at the time of use, its molecular chain is cut by irradiation of an electromagnetic wave or an electron beam or the like, and the polymer exhibits adhesiveness.

The monomers for obtaining the polymer of the present invention include alkyl (meth) acrylates having 2 to 14 carbon atoms, alkyl vinyl ethers and alkyl vinyl esters. Specific examples of the alkyl group include JP-A-9-279113 (column 4, line 13 to
17). Further, JP-A-6-192341 (column 3, line 49 to column 4, line 20)
Row), a hydrophilic monomer described in JP-A-9-87609
(Column 3, line 1 to line 24), monomers copolymerizable with long-chain alkyl (meth) acrylates, conjugated dienes represented by butadiene, isoprene, chloroprene, and ethylene. And monoenes represented by α-olefins may be copolymerized.

When the glass transition temperature of the polymer is -10 ° C. or lower, particularly -30 ° C. or lower, the tackiness may be remarkable. Can be suitably used in the present invention by forming a non-adhesive or low-adhesive polymer in combination. Here, the crosslinkable compound is a compound having two or more functional groups in a molecule, and specifically, is disclosed in JP-A-9-279113 (column 5, column 17).
A monomer having two or more radically polymerizable unsaturated groups, at least one radically polymerizable unsaturated group and an alkylol group or an alkoxymethyl A monomer having at least one radically polymerizable unsaturated group, a monomer having at least one radically polymerizable unsaturated group and an epoxy group or an isocyanate group, and a silane monomer having at least one radically polymerizable unsaturated group. And monomers having the same isocyanate group.
Crosslinkable compounds having these radically polymerizable unsaturated groups,
Copolymerization may be performed by adding before or during polymerization,
It may be added after the completion of the polymerization and further polymerized. Further, it may be added to a separately-obtained adhesive polymer to further polymerize.

In addition, compounds which do not have radically polymerizable unsaturated groups but which contain a plurality of epoxy groups such as glycidyl ethers of polyols such as pentaerythritol, glycerin, trimethylolpropane, etc. Compounds containing a plurality of isocyanate groups, such as 1,4-phenylene diisocyanate, tolylene diisocyanate, trans-1,4-cyclohexane diisocyanate, and the like. These crosslinkable compounds having no radically polymerizable unsaturated group may be added together with the monomer at the time of polymerization, or may be added as a crosslinking agent after the polymerization.

When the reaction is carried out by containing an epoxy group or isocyanate group-containing compound in the starting monomer,
It is preferable to include a monomer having a functional group capable of reacting with an epoxy group or an isocyanate group such as a carboxyl group, a hydroxyl group, and an amino group.

The crosslinkable compound is allowed to react by being contained in a raw material in such an amount that the resulting polymer becomes non-tacky or low-tacky. The preferred amount of the crosslinkable compound is 0.3 parts by weight or more, more preferably 0.5 parts by weight or more, with respect to 100 parts by weight of the raw material monomer or raw material polymer, from the viewpoint of reducing the tackiness.
0.8 parts by weight or more, and from the viewpoint of exhibiting adhesiveness to the polymer when the molecular chain is cut by an electromagnetic wave or an electron beam or the like, 100 parts by weight or less, further 50 parts by weight or less, particularly 30 parts by weight or less.
Not more than parts by weight. Therefore, the amount of the crosslinkable compound used is
With respect to 100 parts by weight of the raw material monomer or raw material polymer, from the viewpoint of reducing the adhesiveness and causing the polymer to exhibit adhesiveness when the molecular chain is cut by electromagnetic waves or electron beams, etc.
The amount is preferably 3 to 100 parts by weight, more preferably 0.5 to 50 parts by weight, particularly preferably 0.8 to 30 parts by weight.

As a more preferred example of the polymer of the present invention,
Examples thereof include those obtained by polymerizing a raw material monomer containing the above-mentioned crosslinkable compound with a photodegradable monomer and / or a sensitizer.

The photodegradable monomer functions to make it easier to break the molecular chain when the monomer is incorporated into a part of the polymer and irradiated with an electromagnetic wave or an electron beam, Thereby, the cleavage of the main chain of the polymer can be drastically promoted. Specifically, a polymerizable monomer used as a raw material for a positive photoresist can be preferably used, and examples thereof include the following. That is, Zenjiro Osawa, “Photodegradation and stabilization of polymers”, pp. 235-247 (198
6), CMC, Masahiro Tsunooka, et al., "Polymer Beam Processing"-Use of Light, Plasma, and Radiation-(Photodegradation Reaction of Polymers and Their Use), 24-34 (1986), Society of Polymer Science Monomers used as a raw material of a photodegradable polymer material used for a positive photoresist as listed in “Handbook of New Polymer Materials”, p. 143, Table 3.45 (1989). Specifically, for example, phenylisopropenyl ketone,
Vinyl ketones such as phenyl vinyl ketone and methyl vinyl ketone; methacrylates having an acyloxyimino group (AOI group) such as 3-oxyimino-2-butanone-methacrylate; and fluoroalkyl groups such as 1H, 1H, 3H-hexafluorobutyl methacrylate. Methacrylate, a vinyl monomer having a sulfonyl group such as 2-methyl-1-pentene sulfone, or the like. The photodegradable monomer can be copolymerized by being contained in the raw material monomer,
The resulting polymer undergoes molecular chain scission with high sensitivity to irradiation of electromagnetic waves or electron beams, particularly to irradiation of ultraviolet rays.
For example, in the case of vinyl ketone, the carbonyl group is excited by ultraviolet light, followed by the so-called Norrish type I, Norrish
Induces α and β ruptures such as type II, and the main chain and side chains are cleaved. As a result of this main chain scission, the molecular chain of the obtained polymer is cut, and although the mobility of the molecule has been limited by crosslinking, it can move freely.
It is considered that the adhesive strength is developed. Of the above photodecomposable monomers, vinyl ketones and methacrylates having an acyloxyimino group are preferably used, and phenyl vinyl ketone, phenyl isopropenyl ketone, methyl vinyl ketone and methyl isopropenyl ketone are more preferably used. These photodegradable monomers have a total monomer composition of 100
0.1 to 50 parts by weight per part is used. Within this range, the polymer is effectively decomposed and tackiness is obtained. Good results can be obtained by using these photodegradable monomers in combination with the above-mentioned crosslinking agent.

A sensitizer that promotes photolysis can be used together with these photodegradable ketones. This is preferable because sensitivity is further improved and activation can be easily performed with a small amount of energy irradiation. The most suitable sensitizer depends on the monomer used.
Abstracts of the 14th Semiconductor Integrated Circuit Technology Symposium, '' p. 44 (1
979) In addition to benzoic acid derivatives as described in Table 1, anthracene, phenazine, carbazole, biphenyl, benzoin, iron chloride (FeCl ₃ ), titanium oxide (TiO
₂ ), salicylaldehyde metal complexes, dithiocarbamate metal complexes, and the like. These sensitizers consist of all monomers 10
It is used in an amount of 0.1 to 30 parts by weight based on 0 part. Efficient sensitization is achieved with an addition amount within this range.

In a more preferred embodiment of the present invention, the monomer composition is 10% by weight or more, more preferably 30% by weight or more.
The methacrylic monomer can be used in an amount of at least% by weight.
The monomers described so far include acrylic monomers and vinyl monomers, but methacrylic monomers are necessary to effectively cause the aforementioned Norrish II type main chain cleavage. Is preferably set to 10% by weight or more of the entire monomer composition.

In obtaining a polymer from the above monomer composition,
The polymerization method is not particularly limited, and a general method can be used. That is, a polymer can be obtained by performing ordinary radical polymerization using a method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, and an emulsion polymerization method. As an example of the polymerization method of the present invention, JP-A-6-192341 (column 5, line 2 to
(Col. 6, line 42).

In the present invention, the gel fraction of the polymer thus obtained is preferably 70% or more, more preferably 80% or more. Within these preferred ranges, the polymer exhibits non-tackiness or low-tackiness, and efficiently exhibits adhesive strength when irradiated with electromagnetic waves or electron beams. The method for measuring the gel fraction is described in the section of Examples.

The retardation adhesive of the present invention contains the polymer of the present invention obtained by the above-mentioned method preferably in an amount of 1 to 80% by weight, more preferably 10 to 70% by weight, particularly preferably 30 to 60% by weight.
contains.

Further, a tackifier may be added to the retardation adhesive of the present invention in order to adjust the adhesion performance. Examples of the tackifier include terpene resins, aliphatic petroleum resins, aromatic petroleum resins, cumarone-indene resins, styrene resins, phenol resins, terpene-phenol resins, rosin derivatives (for example, rosin, polymerized rosin and Hydrogenated rosins, their esters with glycerin, pentaerythritol and the like, and resin acid dimers).
In addition, if necessary, a plasticizer, a thickener, a stabilizer, a preservative, and a leveling agent may be added. These may be those generally used for adhesives.

The delayed adhesive product of the present invention is provided with a layer comprising the above-mentioned delayed adhesive of the present invention on a substrate.

In the present invention, in order to form a delayed pressure-sensitive adhesive layer on a substrate, for example, the emulsion containing the polymer of the present invention obtained as described above is coated on the substrate by an appropriate method. It may be applied and dried.

As a specific method, for example, a comma coater, a gravure coater, a roll coater, a die coater, a lip coater, a PET (polyethylene terephthalate) or an OPP (stretched polypropylene) film are used.
A method of coating and drying the polymer using a known coating machine such as a Meyer coater may be used. When forming a delayed pressure-sensitive adhesive layer on a substrate having a shape other than a film or a sheet, it may be applied with a brush or the like. The drying temperature is not particularly limited, and drying can be performed under ordinary temperature conditions.

The substrate in the present invention may be of any material and shape as long as it can form a delayed pressure-sensitive adhesive layer. Specific examples of materials include plastics such as polyethylene, polypropylene, polyester, polystyrene, acrylic, and ABS; metals such as iron, aluminum, and stainless steel; and other materials such as glass, paper, wood, setware, ceramics, concrete, and stone. Is mentioned.

Examples of the specific shape of the substrate include:
Film-shaped and sheet-shaped are preferred representative examples, but any shape such as a box, a rod, a sphere, a cone, a pipe, and a fiber may be used as long as the delay adhesive layer can be formed thereon. is not. In the present invention, after forming a delayed pressure-sensitive adhesive layer having no tackiness on such a base material, the substrate is adhered to the adherend while exhibiting tackiness.

In the present invention, the delayed pressure-sensitive adhesive layer having no tackiness should ideally have no tackiness at all, but may have low tackiness. The amount of application after drying the delay adhesive on top is 10 ~
In the pressure-sensitive adhesive film obtained by coating and drying to 50 g / m ² , the adhesive strength when using a high-density polyethylene plate (HiZEX 5000H, extruded product manufactured by Mitsui Petrochemical Co., Ltd.) as the adherend, It is 196 cN / 25 mm (200 gf / 25 mm) or less, preferably 98 cN / 25 mm (100 gf / 25 mm) or less, more preferably 49 cN / 25 mm (50 gf / 25 mm) or less. Here, the adhesive strength is obtained by cutting the base film having the delayed adhesive layer formed thereon to a width of 25 mm, attaching the substrate film to an adherend, and measuring it in accordance with JIS Z 0237 180-degree peeling method.

The thickness of the formed delayed pressure-sensitive adhesive layer after drying is preferably 200 g / m ² or less, more preferably ² to 100 g / m ² , when expressed in terms of coating amount. Within this range,
A molecular chain can be effectively cut at the time of irradiation with an electromagnetic wave or an electron beam, and a suitable adhesive strength can be obtained.

In the present invention, the delayed adhesive product of the present invention is irradiated with an electromagnetic wave or an electron beam to cut the molecular chains of the polymer in the delayed adhesive layer, thereby exhibiting adhesiveness in the delayed adhesive layer. After that, it is attached to the adherend. The electromagnetic waves and electron beams used preferably have a wavelength of 450 nm or less.

Irradiation with ultraviolet light is particularly effective. Ultraviolet rays having a center wavelength in the range of 150 to 450 nm are preferably used. High-pressure mercury lamps, ultra-high-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, deep UV lamps, excimer laser lamps, and the like can be used as light sources that emit ultraviolet light in such a wavelength range.

The irradiation device is not particularly limited, and may be a continuous irradiation device with a conveyor, an intermittent operation device, or a spot irradiation device. The total amount of energy irradiation, from the viewpoint of tackiness after irradiation, with measurement using 365nm as an absolute value calibration wavelengths, 0.005 J / cm ² or more, preferably 0.05 J / cm ² or more, and excessive molecular chain lowering the holding force due to disconnection, from the viewpoint of preventing a decrease adhesive strength, 3000 J / cm ² or less, preferably 1000 J / cm ² or less. The total amount of energy to be irradiated, preferably 0.05~1000J / cm ^2, more preferably 0.
It is from 0.05 to 100 J / cm ² , particularly preferably from 0.1 to 10 J / cm ² .
The irradiation time is within 1 hour, preferably within 10 minutes, more preferably within 1 minute.

[0039]

According to the present invention, since a method of developing tackiness by cutting a molecular chain is used instead of a conventional delaying adhesive by a heating method, the blocking resistance during storage is good, and Coating efficiency can be obtained, no chalking phenomenon occurs, and neither whitening nor embrittlement with time after activation occurs.

The present invention not only solves the above-mentioned drawbacks of the conventional heat-sensitive delay adhesive at once, but also adjusts the irradiation amount in order to develop adhesiveness by irradiation of electromagnetic waves or electron beams. Thereby, the adhesive strength can be arbitrarily controlled. In addition, it is a method that can provide an epoch-making function that cannot be provided by a conventional heat-sensitive delay adhesive, for example, by limiting the irradiation site by a method such as a light-shielding plate or the like, thereby controlling the adhesive development site.

The present invention is applicable to not only film and sheet adhesive products such as labels and tapes, but also products having a complicated shape so that a delay adhesive layer can be formed on the surface thereof. Then, it can be applied to anything.

[0042]

EXAMPLES In the examples, "%" means "% by weight" unless otherwise specified.
It is. Further, a film having a delayed pressure-sensitive adhesive layer formed thereon (hereinafter, referred to as a delayed pressure-sensitive adhesive film) was produced as described below, and the adhesive force and gel fraction of the polymer were measured by the following methods. The solid content of the polymer emulsion was determined by model fd-230 manufactured by Kett Science Laboratory (setting: 150 ° C, 98
min) and the particle size of the polymer emulsion is HORIBA lt
d. Performed using LA-910 (setting: refractive index 1.20). Table 1 shows the results.

(1) Preparation of Delayed Adhesive Film The polymer emulsions obtained in Examples 1 to 3 were
A bar coater type coating machine (Yasuda) is applied to the corona-treated surface of a thick PET film substrate (Lumilar S105, manufactured by Toray Industries, Inc.).
Seiki Ltd., No.542-AB automatic film applicator in), the coating amount after drying is 23 g / m ² as coated speed 3m /
Coated at min. Next, a hot air dryer (TABAI MFG.Co.L
Drying was performed at 110 ° C. for 1 minute using TD (model p-23) to obtain a delayed adhesive film.

(2) Adhesive strength The delayed adhesive film was cut into a width of 25 mm, and immediately adhered to a high-density polyethylene plate (HIZEX 5000H manufactured by Mitsui Petrochemical Co., Ltd., extruded product, hereinafter referred to as HDPE plate) as an adherend. The adhesive strength was measured according to the 180 ° peeling method of JIS Z 0237. The measurement of the adhesive strength was performed for each of the delayed adhesive films before and after the irradiation of the ultraviolet rays. In addition, ultraviolet rays
UV irradiation device (HMW-713, manufactured by Oak Manufacturing Co., Ltd.)
And irradiated directly from the side of the delayed pressure-sensitive adhesive layer. A high-pressure mercury lamp (120 W / cm 2) was used as an ultraviolet lamp, and the integrated irradiation amount was as shown in Table 1 (both absolute value calibration wavelength 365 nm).

(3) Gel fraction The polymer was scraped from the adhesive film with a spatula,
accurately weigh about 0.2 g into a glass container
80 ml of F 2 solvent was added to dissolve. After leaving this solution at 23 ° C. for 24 hours, the solution was filtered through a 200-mesh wire net (15 cm × 15 cm) to remove undissolved polymer. After evaporating the solvent of the polymer portion remaining on the wire mesh at 100 ° C. for 2 hours,
The weight of the polymer was measured, and the gel fraction was determined by the following equation. Gel fraction (%) = weight of polymer remaining on wire mesh (g) / total weight of collected polymer (g) × 100 The gel fraction was also measured for each of the delayed adhesive films before and after ultraviolet irradiation.

Example 1 In a 2-liter container, latemul S-18 having an effective concentration of 2.0% was added.
0 400 g of an aqueous solution (manufactured by Kao Corporation; polymerizable surfactant) was charged, and 394 g of lauryl methacrylate and polyethylene glycol dimethacrylate (NK ester 4) prepared separately were prepared.
G, Shin-Nakamura Chemical Co., Ltd.) 6 g, 2,2'-azobis-2-
A monomer solution obtained by mixing 1.2 g of methylbutyronitrile (V-59, manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was treated with a milder (manufactured by Ebara Corporation) while cooling for 20 minutes to obtain an emulsion. Was. The average particle size of this emulsion was 0.45 μm.

The emulsified product was transferred to a 2 liter glass reaction vessel, purged with nitrogen, and then heated while stirring.
The mixture was reacted at 6 ° C. for 6 hours to obtain a polymer emulsion. This polymer emulsion has a solid content of 50.1% and an average particle size of 0.48μ.
m.

Next, using this polymer emulsion, a delayed adhesive film was obtained by the above method. This delayed pressure-sensitive adhesive layer showed almost no tackiness. The gel fraction was measured and found to be 85%.

Example 2 The monomer solution composition of Example 1 was changed to lauryl methacrylate.
388 g, trimethylolpropane trimethacrylate (NK
Ester TMPT, Shin-Nakamura Chemical Co., Ltd.) 4 g, Methyl vinyl ketone (reagent, Kanto Chemical Co., Ltd.) 8 g, 2,2'-
The same treatment as in Example 1 was carried out except that the amount was changed to 1.2 g of azobis-2-methylbutyronitrile (V-59, manufactured by Wako Pure Chemical Industries, Ltd.) to obtain a polymer emulsion. The solid content of this polymer emulsion was 50.3%, and the average particle size was 0.55 μm.

Next, this polymer emulsion was applied to a PET film substrate in the same manner as in Example 1 to obtain a delayed adhesive film. This delayed pressure-sensitive adhesive layer showed almost no tackiness.
The gel fraction was measured and found to be 92%.

Example 3 The composition of the monomer solution of Example 1 was changed to lauryl methacrylate.
384g, polyethylene glycol dimethacrylate (NK ester 4G, Shin-Nakamura Chemical Co., Ltd.) 6g, phenylisopropenyl ketone 10g, 2,2'-azobis-2-methylbutyronitrile (V-59, Wako Pure Chemical Industries, Ltd.) The same treatment as in Example 1 was carried out except that the amount was changed to 1.2 g (produced by the company) to obtain a polymer emulsion. In addition, phenylisopropenyl ketone is
Reference J. Polym. Sci. Polymer Chemistry Edition, 14, 1901
The synthesized one was used based on -1913 (1976). The solid content of this polymer emulsion is 50.3%, average particle size is 0.52μ
m.

Next, this polymer emulsion was applied to a PET film substrate in the same manner as in Example 1 to obtain a delayed adhesive film. This delayed pressure-sensitive adhesive layer showed almost no tackiness.
The gel fraction was measured and found to be 87%.

[0053]

[Table 1]

(Results) In the delayed pressure-sensitive adhesive films of Examples 1 to 3, the delayed pressure-sensitive adhesive layer became tacky according to the irradiation amount of ultraviolet rays. In particular, in Examples 2 and 3, the sensitivity was higher than that in Example 1, and cohesive failure was shown by irradiation at 4000 mJ / cm ² .

Continued on the front page F term (reference) 4J004 AA08 AA09 AA10 AB01 4J027 AA01 AA03 AC03 AC06 BA04 BA07 CA29 CB10 CC02 CC05 CD09 4J040 DD051 DE011 DF011 JA09 JB09 PA32 4J100 AF10Q AL03P AL04P AL05P AL08Q BA01Q01 BA03 BA03 HE44 JA03 JA05

Claims (5)

[Claims] 1. A delayed pressure-sensitive adhesive containing a polymer that exhibits tackiness by breaking a molecular chain. 2. The delayed pressure-sensitive adhesive according to claim 1, wherein the polymer is obtained by allowing a monomer or polymer as a raw material to contain a crosslinkable compound and reacting. 3. A delayed pressure-sensitive adhesive containing a polymer that develops tackiness upon irradiation with an electromagnetic wave or an electron beam. 4. A delayed pressure-sensitive adhesive product comprising a substrate comprising a layer comprising the delayed pressure-sensitive adhesive according to claim 1. 5. A delayed pressure-sensitive adhesive product comprising a substrate and a delayed pressure-sensitive adhesive layer containing a polymer which is provided on the substrate and exhibits tackiness by cutting molecular chains, wherein the delayed pressure-sensitive adhesive layer contains A method for sticking a delayed sticky product, which sticks to an adherend after the stickiness is developed by cutting the molecular chain of the polymer.