JP2000001653A - Acrylic adhesive tape or sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an acrylic adhesive tape or sheet capable of being adhered to even an oil-adhering surface, capable of exhibiting proper repeelability, good antistaining property, good weather resistance and good light resistance, and useful for protecting various kinds of members by laminating an adhesive layer comprising a specific acrylic adhesive (composition) to a substrate. SOLUTION: This acrylic adhesive tape or sheet is obtained by laminating (A) an adhesive layer comprising an acrylic copolymer (composition) obtained by copolymerizing (A1) an alkyl (meth)acrylate having a 1-14C alkyl group with (A2) an olefin macromer to (B) one surface of a substrate (for example, a polyolefin substrate surface or a polyolefin substrate surface preliminarily coated with the component A).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylic pressure-sensitive adhesive tape or sheet, and more particularly, to an acrylic pressure-sensitive adhesive tape or sheet which is excellent in oil resistance, light resistance and weather resistance and has a suitable removability. Regarding the sheet.

[0002]

2. Description of the Related Art In order to protect members, protective films or sheets made of films or sheets made of synthetic resin are widely used. That is, this kind of protective film or sheet is widely used for protection of a metal plate such as stainless steel or aluminum, a precoated steel plate, a decorative plate, a plastic plate, a name plate, an aluminum sash, etc. during processing, curing or transportation. I have.

By the way, as a processing method applied to the above-mentioned members, various processing methods such as bender processing, roll forming processing, drawing processing, and punching processing can be mentioned. In many cases, processing is performed one after another by one processing machine. Is performed. Therefore, since the processing jig gradually heats up, cutting oil is usually used for cooling. However, the cutting oil reduces the adhesive strength of the protective film or sheet, so it peels off from the area where the adhesive strength is reduced, scratches the processed member, contaminates the surface of the member, and reduces the commercial value. Was sometimes impaired.

For example, JP-A-61-103975 discloses that 100 parts by weight of ABA (A represents a styrene polymer block, B represents an ethylene-butylene copolymer block), An adhesive film for surface protection is disclosed in which a pressure-sensitive adhesive layer comprising a composition containing 〜80 parts by weight is formed on a substrate made of polyolefin.
However, in the adhesive film for surface protection described in this prior art, although the anchoring force of the pressure-sensitive adhesive layer on the substrate is excellent, the weather resistance and the oil resistance are not sufficient.

[0005] Further, if the adhesive strength of the protective film or sheet is too high in order to suppress the separation by oil,
During use, it becomes difficult to peel off the protective film or sheet from the protected member.

Further, in applications where weather resistance and light resistance are particularly required, such as outdoor applications, a protective film obtained by applying a solution of an acrylic pressure-sensitive adhesive to a substrate made of a vinyl chloride resin or polyolefin is used. . However, since this kind of protective film must be peeled off when a protected member is used, it is configured to be easily peeled off from the protected member. For example, the release property is enhanced by blending a release agent such as silicone oil with the acrylic adhesive. However, the surface of the protected member may be contaminated by the release agent.

On the other hand, the acrylic copolymer itself has tackiness and can be used as an adhesive without adding a tackifier resin. Therefore, acrylic adhesives using an acrylic copolymer have been used for various purposes. Used in.

Various acrylic pressure-sensitive adhesive sheets comprising an acrylic pressure-sensitive adhesive layer containing the above acrylic copolymer as a main component and laminated on at least one surface of a substrate have been proposed (for example, Japanese Patent Publication No. 51-48773). Gazette).

However, if a tackifying resin is added to the pressure-sensitive adhesive layer in the conventional acrylic pressure-sensitive adhesive sheet in order to enhance the tackiness, the anchoring force of the pressure-sensitive adhesive on the base material is reduced, and adhesive residue tends to be left. Therefore, this type of acrylic pressure-sensitive adhesive sheet was insufficient for use in applications requiring removability, such as the surface protective film described above.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to overcome the above-mentioned drawbacks of the prior art, to show good adhesion even when oil is adhered, and to have proper removability and non-contamination of adherends. It is an object of the present invention to provide an acrylic pressure-sensitive adhesive tape or sheet that can balance the properties and can be suitably used for applications requiring weather resistance and light resistance.

[0011]

The acrylic pressure-sensitive adhesive tape or sheet according to the first aspect of the present invention has 1 carbon atoms.
An acrylic copolymer obtained by copolymerizing a polymerizable composition containing an alkyl (meth) acrylate (a) having an alkyl group of from 1 to 14 and an olefin macromer (b) or the acrylic copolymer A pressure-sensitive adhesive layer comprising an acrylic pressure-sensitive adhesive composition is laminated on one surface of a substrate.

In the invention according to claim 2, the substrate is made of a polyolefin substrate, and the pressure-sensitive adhesive layer is directly laminated on the polyolefin substrate. In the invention according to claim 3, the base material is a polyolefin base material, and the pressure-sensitive adhesive layer is laminated on the polyolefin base material via an intermediate layer.

According to a fourth aspect of the present invention, there is provided an acrylic pressure-sensitive adhesive tape or sheet in which a polyolefin substrate, an intermediate layer and an acrylic pressure-sensitive adhesive layer are coextruded and integrated, wherein the intermediate layer is made of carbon. Acrylic copolymer obtained by copolymerizing a polymerizable composition containing an alkyl (meth) acrylate (a) having an alkyl group of Formulas 1 to 14 and an olefin macromer (b), or the acrylic copolymer It is characterized by being composed of a composition containing coalescing. Hereinafter, details of the present invention will be described.

(Acrylic pressure-sensitive adhesive tape or sheet according to the first to third aspects of the present invention) The alkyl (meth) acrylate (a) having an alkyl group having 1 to 14 carbon atoms used in the present invention is methyl. (Meth) acrylate, ethyl acrylate, n-propyl (meth)
Acrylate, isopropyl (meth) acrylate, n
-Butyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate,
Cyclohexyl methacrylate, n-octyl (meth)
Acrylate, isooctyl acrylate, 2-ethylhexyl (meth) acrylate, isononyl acrylate, lauryl (meth) acrylate, and the like can be given. The expression (meth) acrylate is a general term for acrylate and methacrylate.

The above alkyl (meth) acrylates may be used alone or in combination of two or more. The olefin macromer (b) used in the present invention is an olefin polymer whose terminal is modified with a radically polymerizable unsaturated double bond, and is a double bond copolymerizable with another polymerizable monomer. Is not particularly limited as long as it has a structure such as polyethylene, polypropylene or ethylene-butylene copolymer. A double bond copolymerizable with another polymerizable monomer means a radically polymerizable unsaturated double bond, for example, a vinyl group,
Examples thereof include a (meth) acryloyl group and an allyl group.

As a specific example of the olefin macromer (b), there is a trade name "KRAT" in which the terminal of an ethylene-butylene copolymer is modified with methyl methacrylate.
ON LIQUID Polymer HPVM-1253 "(Shell Chemical Com
pany), JP-A-5-194630, JP-A-5-247119, JP-A-6-32847, JP-A-7-2928 and the like.
Compounds in which the terminal of polypropylene or an ethylene-propylene random copolymer is modified with a (meth) acrylate such as methacrylic acid methyl ester can be given.

In the present invention, in addition to the alkyl (meth) acrylate (a) and the olefin macromer (b), the glass transition temperature of the resulting acrylic copolymer and the adhesive strength of the adhesive composition are adjusted. , Stearyl (meth) acrylate, isomyristyl (meth)
Alkyl (meth) having an alkyl group having 15 to 25 carbon atoms, such as acrylate and lauryl (meth) acrylate
Acrylates; styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene; vinyl alcohol esters of alkyl carboxylic acids such as vinyl acetate; vinyl carboxylic acids such as acrylic acid, methacrylic acid or itaconic acid; maleic anhydride Copolymerizable with vinyl-containing vinyl monomers such as 2-hydroxyethyl (meth) acrylate; nitrogen-containing vinyl monomers such as (meth) acrylonitrile, N-vinylpyrrolidone or acryloylmorpholine. Other vinyl monomers may be used in combination.

The copolymerization ratio of the olefin macromer (b) in the acrylic copolymer is preferably in the range of 2 to 50% by weight based on 100% by weight of the acrylic copolymer. When the amount is less than 2% by weight, the adhesive strength to the oil surface may not be sufficiently increased, and when the amount is more than 50% by weight, the pressure-sensitive adhesive solution tends to gel, and the practicability may decrease.

The weight average molecular weight of the acrylic copolymer is preferably from 10,000 to 4,000,000, more preferably from 200,000 to 2,000,000. If less than 10,000,
The properties as a copolymer may not be exhibited, and 4
If it exceeds one million, the viscosity at the time of production becomes high, which is not preferable in terms of productivity.

In the acrylic pressure-sensitive adhesive tape or sheet according to the present invention, a pressure-sensitive adhesive layer comprising an acrylic pressure-sensitive adhesive composition containing the above acrylic copolymer is laminated on one surface of a substrate. This lamination method is not particularly limited, either.
The pressure-sensitive adhesive composition may be laminated on one surface of the substrate by applying a solution. Alternatively, the substrate and the pressure-sensitive adhesive layer may be laminated on the substrate by co-extrusion. In this case, an intermediate layer may be interposed between the base material and the pressure-sensitive adhesive layer.

In the acrylic pressure-sensitive adhesive tape or sheet according to the present invention, it is preferable that the acrylic copolymer is cross-linked in order to exhibit a proper removability. When the acrylic pressure-sensitive adhesive composition is solution-coated on the substrate surface, any ordinary crosslinking method such as chemical crosslinking, physical crosslinking, electron beam crosslinking, or ultraviolet crosslinking can be used as appropriate. On the other hand, when laminating the pressure-sensitive adhesive layer to the substrate by co-extrusion, chemical cross-linking cannot be used, and a method of physically cross-linking using an acrylic copolymer having physical cross-linking property, or After forming into a film or a sheet, a method of crosslinking by electron beam crosslinking or ultraviolet crosslinking may be used.

To chemically crosslink the acrylic copolymer, a (meth) acrylate monomer having a functional group such as a hydroxyl group, a carboxyl group, a glycidyl group, a methylol group, or an amino group is previously copolymerized with the acrylic copolymer. Polymerization may be carried out, and a crosslinking agent which reacts with the above functional group may be blended.
Crosslinking agents include melamine resins, iodine resins, polyisocyanates, epoxy resins, metal oxides, metal peroxides, metal salts, metal hydroxides, metal chelates, polymers containing carboxyl groups, acid anhydrides, polyamines, carboxyl groups Included polymers, polyisocyanates, and the like.

In order to physically crosslink the acrylic copolymer, one of the (co) polymers having a glass transition point Tg of 40 ° C. or higher is used.
An acrylic copolymer having a block copolymer structure having the above blocks or a graft copolymer structure having a (co) weight part having a glass transition point Tg of 40 ° C. or more in a side chain or a main chain may be used.

Examples of the (co) polymer having a glass transition point Tg of 40 ° C. or higher include polystyrene, polyethyl methacrylate, polyα-methylstyrene and the like, or alkyl (meth) having an alkyl group having 1 to 14 carbon atoms. ) Copolymers with acrylates and the like.

In order to form a block copolymer structure, coordination anion polymerization using a rare earth metallocene complex catalyst or the like, a polyfunctional peroxide having two or more peroxide groups in one molecule, and a vinyl group in one molecule Any known method such as a multi-stage polymerization using a peroxide monomer having a compound and a peroxide group or a polyvalent mercaptan having two or more mercapto groups in one molecule can be used.

In order to form a graft copolymer structure, multi-stage polymerization using a peroxide monomer having one or more unsaturated double bonds and one or more peroxide groups in one molecule, a glass transition point Tg May be copolymerized at 40 ° C. or higher with a macromonomer whose terminal is modified with a radically polymerizable unsaturated double bond.

A solvent-free liquid mixture comprising the above alkyl (meth) acrylate, an ethylene-butylene random copolymer having a terminal modified with a radically polymerizable unsaturated double bond, a photopolymerization initiator and a photoactive crosslinking agent. May be applied to a support and polymerized by irradiation with ultraviolet light in an inert gas such as nitrogen to obtain a pressure-sensitive adhesive layer.

In the acrylic pressure-sensitive adhesive tape or sheet according to the present invention, the acrylic pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer contains the above-mentioned acrylic copolymer as an essential component. , A hydrogenated petroleum resin, or the above-mentioned crosslinking agent for improving cohesion.

The pressure-sensitive adhesive composition may further contain, if necessary, various known additives such as tackifier resins, plasticizers, softeners, and fillers within a range not to impair the object of the present invention. , A stabilizer, an antioxidant, a pigment, a dye, and the like.

(Substrate) In the acrylic pressure-sensitive adhesive tape or sheet according to the present invention, the above-mentioned pressure-sensitive adhesive layer is laminated on one surface of the substrate, but this substrate is not particularly limited. Preferably, a polyolefin substrate is used. As the polyolefin, polyethylene,
Any flexible polyolefin film or sheet containing ethylene and / or propylene as a main component, such as polypropylene, can be used.

Examples of the polyethylene include high-density polyethylene (HDPE), medium-density polyethylene (MDPE), and linear low-density polyethylene (LLDPE), and long-chain polyethylene such as 1-butene and 1-pentene. An olefin monomer may be copolymerized.

Examples of the polypropylene include random polypropylene, homopolypropylene, high crystallinity polypropylene, block polypropylene and the like, but are not limited to these as long as they have flexibility.

The pressure-sensitive adhesive layer may be directly laminated on the polyolefin substrate, or may be laminated via an intermediate layer. That is, a polyolefin layer,
An intermediate layer may be interposed to enhance the anchoring property with the pressure-sensitive adhesive layer.

The resin used as the intermediate layer is not particularly limited as long as it can enhance the anchoring property of the pressure-sensitive adhesive layer. EEA resin (ethylene-ethyl acrylate copolymer: Primacor, manufactured by Dow Chemical Co., Ltd.) ,
It is a resin having high polarity such as anhydrous maleated polyethylene and epoxy-modified polyethylene, and a resin obtained by deforming a polyolefin such as polyethylene or polypropylene is preferably used.

When the acrylic pressure-sensitive adhesive layer is laminated on the base material via the intermediate layer as described above, the acrylic pressure-sensitive adhesive composition, the material for forming the intermediate layer, and the material for forming the base material are co-extruded. A method of laminating and integrating these can be suitably used.

(Acrylic pressure-sensitive adhesive tape or sheet according to the fourth aspect) In the acrylic pressure-sensitive adhesive tape or sheet according to the fourth aspect, a polyolefin base material, an intermediate layer, and an acrylic pressure-sensitive adhesive The layers are coextruded and integrated.

The components constituting the acrylic pressure-sensitive adhesive layer are not particularly limited, but are preferably 50 to 98% by weight of an alkyl (meth) acrylate having an alkyl group having 1 to 14 carbon atoms, The main component is an acrylic copolymer obtained by copolymerizing a vinyl monomer having a polar group with 2 to 50% by weight in these proportions.

As the alkyl (meth) acrylate having an alkyl group having 1 to 14 carbon atoms, the above-mentioned (1)
One or more of those exemplified in the invention described in (1) can be used.

In order to adjust the glass transition point of the acrylic copolymer and the adhesive strength of the acrylic pressure-sensitive adhesive layer, styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene,
Copolymerizable vinyl monomers such as methyl styrene and vinyl alcohol esters of alkyl carboxylic acids such as vinyl acetate may be used in combination.

The vinyl monomer having a polar group is not particularly limited. For example, vinyl carboxylic acid such as acrylic acid, methacrylic acid or itaconic acid; vinyl carboxylic anhydride such as maleic anhydride; Examples thereof include hydroxyl-containing vinyl monomers such as 2-hydroxyethyl (meth) acrylate, and nitrogen-containing vinyl monomers such as (meth) acrylonitrile, N-vinylpyrrolidone, and acryloylmorpholine.

The acrylic pressure-sensitive adhesive layer may contain a crosslinking agent in addition to the acrylic copolymer in order to increase cohesion. As the crosslinking agent, a conventionally known crosslinking agent can be used, and examples thereof include an isocyanate-based crosslinking agent, an aziridine-based crosslinking agent, and an epoxy-based crosslinking agent.

Further, the acrylic pressure-sensitive adhesive composition includes:
Various additives, for example, tackifier resins, plasticizers, softeners, fillers, stabilizers, antioxidants, pigments, dyes, and the like, as needed, as long as the object of the invention described in claim 4 is not hindered. May be contained.

The intermediate layer according to the fourth aspect of the present invention comprises:
Alkyl (meth) having an alkyl group having 1 to 14 carbon atoms
It is composed of an acrylic copolymer obtained by copolymerizing a polymerizable composition containing an acrylate (a) and an olefin macromer (b) or a composition containing the acrylic copolymer. That is, the material constituting the intermediate layer is the same as the acrylic pressure-sensitive adhesive layer used in the acrylic pressure-sensitive adhesive tape or sheet according to the first aspect of the present invention. Therefore, regarding the material constituting the intermediate layer in the acrylic pressure-sensitive adhesive tape or sheet according to the invention of claim 4, the description of the acrylic pressure-sensitive adhesive layer in the acrylic pressure-sensitive adhesive tape or sheet according to the invention of claim 1 Will be omitted with the aid of

The thickness of the intermediate layer is not particularly limited, but is preferably in the range of 3 to 20 μm. With the current technology, a thickness variation of about several μm occurs in the width direction and the coating direction, so if the thickness of the intermediate layer is less than 3 μm, a portion without the intermediate layer is formed, and the base of the acrylic pressure-sensitive adhesive layer is formed. The effect of increasing the bonding strength to the material may not be sufficiently obtained. Further, even when the thickness of the intermediate layer exceeds 20 μm, the bonding strength of the acrylic pressure-sensitive adhesive layer to the base material does not increase so much, which is wasteful in terms of cost, and the layer is easily relaxed at the time of re-peeling. In some cases, the re-peeling force may increase.

In the invention according to claim 4, the same polyolefin substrate as used in the invention according to claim 1 can be used as the polyolefin substrate.

According to the fourth aspect of the present invention, the polyolefin substrate, the acrylic pressure-sensitive adhesive layer and the intermediate layer are co-extruded and integrated. The specific method of integrating by co-extrusion is also not particularly limited, but the materials constituting the polyolefin base material, the acrylic pressure-sensitive adhesive layer, and the intermediate layer are each simultaneously extruded from different extruders. , By co-extrusion of three layers by an inflation method, a T-die method or other methods.

The acrylic pressure-sensitive adhesive tape or sheet obtained by coextrusion as described above is irradiated with an electron beam or the like to crosslink the acrylic pressure-sensitive adhesive layer or to increase the anchoring force between the layers. You may.

(Function) In the acrylic pressure-sensitive adhesive tape or sheet according to the first aspect of the present invention, the acrylic pressure-sensitive adhesive layer comprises an alkyl (meth) acrylate (a) having an alkyl group having 1 to 14 carbon atoms; An acrylic copolymer obtained by copolymerizing a polymerizable composition containing the olefin macromer (b) is included as an essential component. Here, since the olefin macromer is copolymerized,
Alternatively, adhesion promotion when light is applied is small, and oil resistance is also improved. Also, there is little decrease in peeling force when oil adheres. This is considered to be due to the lower polarity of the acrylic pressure-sensitive adhesive layer due to olefin macromer copolymerization.

According to the second aspect of the present invention, since the acrylic pressure-sensitive adhesive layer is directly laminated on the polyolefin substrate, it is only necessary to apply or transfer the acrylic pressure-sensitive adhesive on the polyolefin substrate. The acrylic pressure-sensitive adhesive tape or sheet according to the first aspect of the present invention can be easily formed.

According to the third aspect of the present invention, since the acrylic pressure-sensitive adhesive layer is laminated on the polyolefin substrate via the intermediate layer, the acrylic pressure-sensitive adhesive layer is selected by selecting the material constituting the intermediate layer. The bonding strength of the agent layer to the substrate can be increased.

In the invention according to claim 4, the acrylic pressure-sensitive adhesive layer is coextruded with the intermediate layer and the polyolefin substrate to be integrated, and the intermediate layer has an alkyl group having 1 to 14 carbon atoms. Alkyl (meth) acrylate (a)
And an acrylic copolymer obtained by copolymerizing a polymerizable composition containing olefin macromer (b)
The intermediate layer has a high anchoring force to the polyolefin substrate,
It is also excellent in oil resistance. Further, the acrylic pressure-sensitive adhesive layer formed on the intermediate layer is firmly joined to the base material via the intermediate layer.

[0052]

The present invention will be more specifically described below with reference to non-limiting examples.

Example 1 Ethyl acrylate (EA)
83 g of an ethylene-butylene random copolymer (Shell) terminal-modified with a radically polymerizable unsaturated double bond
Product name: KRATON LIQUID Polyme, manufactured by Chemical Company
r, HPVM-1253, abbreviated as EB macroma in Table 1) 7 g
And a compound having a copolymerizable double bond and a peroxide bond in one molecule, t-butylperoxyallyl carbonate (trade name: Peromer AC, manufactured by NOF Corporation)
0 g and benzyl methyl ketal as a photopolymerization initiator (trade name: Irgacure 651 manufactured by Ciba Geigy)
0.1 g, and dissolved oxygen was removed by bubbling the resulting monomer mixture with nitrogen gas for 20 minutes.

Next, a weir was provided on the polyester film with a foam tape, the above-mentioned monomer mixture was poured into the weir, and another polyester film was laminated so that no air was left therebetween.

The polymerization was completed by irradiating a light of 365 nm wavelength with an intensity of 17 mW for 60 minutes using a high pressure mercury lamp. Next, 80 g of the polybutyl acrylate polymerized as described above was weighed and placed in a 2 L separable flask equipped with a stirrer, a cooler, a thermometer and a nitrogen gas inlet, and then 20 g of methyl methacrylate was added.
Ethyl acetate was used as a solvent, and the total solid concentration was 5%.
100 g was added so as to be 0% by weight.

The polymer / monomer mixed solution prepared as described above was bubbled with nitrogen gas for 20 minutes to remove dissolved oxygen. Then, the inside of the separable flask was replaced with nitrogen gas, and the mixture was stirred at 60 rpm. The polymer / monomer mixed solution was heated using a water bath. The time when the reflux liquid was confirmed in the cooling tube was defined as the polymerization starting point, and the boiling point polymerization reaction was carried out for 7 hours to obtain a target acrylic copolymer solution. This acrylic copolymer was used as pressure-sensitive adhesive A.

High density polyethylene (manufactured by Asahi Kasei Corporation, product number:
L4470) into a film having a thickness of 50 μm, applying a solution of the pressure-sensitive adhesive A on the high-density polyethylene film so as to have a thickness of 10 μm after drying, and heat-sealing with a hot press at 150 ° C. As a result, a protective film was obtained in which a high-density polyethylene film was used as a base material and a pressure-sensitive adhesive layer composed of pressure-sensitive adhesive A was laminated.

(Example 2) In place of a high-density polyethylene film, a base material having a thickness of 5
A protective film was obtained in the same manner as in Example 1, except that a 0 μm polyester film (manufactured by Lintec Corporation, product number: 5011) was used.

Example 3 A 2 L separable flask equipped with a stirrer, a cooler, a thermometer and a nitrogen gas inlet was charged with 279 g of ethyl acrylate and ethylene terminal-modified with a radical polymerizable unsaturated double bond. -Butylene random copolymer (manufactured by Shell Chemical Company, trade name: KR)
21 g of ATON LIQUID Polymer (HPVM-1253), 123 g of ethyl acetate as a polymerization solvent, and 123 g of toluene were mixed to obtain a monomer mixed solution.

After the dissolved oxygen was removed by bubbling the above-mentioned monomer mixed solution with nitrogen gas for 20 minutes, the inside of the separable flask was replaced with nitrogen gas.
While stirring at a speed of 0 rpm, the monomer mixed solution was heated using a water bath.

When the reflux liquid is confirmed in the cooling pipe, the polymerization start point is determined and 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane (Nippon Oil & Fats Co., Ltd.) as a polymerization initiator is used. (Trade name: Perhexa TMH).
After dissolving 03 g in 1 g of ethyl acetate, the mixture was added and boiling point polymerization was started. One hour after the start of the polymerization, a solution prepared by dissolving 0.05 g of the above-mentioned polymerization initiator in 1 g of ethyl acetate was added again. Also, two hours after the start of the polymerization,
After 3 hours and 4 hours, 0.06 g, 0.3 g, and 0.06 g of di (3,5,5-trimethylhexanoyl) peroxide (trade name: Parloyl 355, manufactured by Nihon Yushi Co., Ltd.).
9 g was dissolved in 1 g of ethyl acetate. The desired acrylic copolymer solution was obtained by conducting the boiling point polymerization for 7 hours. This acrylic copolymer was used as pressure-sensitive adhesive B.

N, N ′ as a crosslinking agent was added to the adhesive B solution.
-Hexamethylene-1,6-bis (1-aziridine cardoxide) in isopropanol solution (solid content 2% by weight)
25 parts by weight were added to 100 parts by weight of the acrylic copolymer and uniformly mixed. Thereafter, on the polyester film substrate used in Example 2, a pressure-sensitive adhesive solution mixed with a crosslinking agent is applied so that the thickness after drying becomes 10 μm, and then, at a temperature of 110 ° C. for 5 minutes. Dried to obtain a protective tape.

Example 4 A 2 L separable flask equipped with a stirrer, a cooler, a thermometer, and a nitrogen gas inlet was charged with 279 g of ethyl acrylate and polypropylene end-modified with a radical polymerizable unsaturated double bond. (Weight average molecular weight Mn = 28000, manufactured by Tonen Chemical Co., Ltd.
21 g of ethyl acetate as a polymerization solvent and 23 g of toluene were blended to obtain a monomer mixed solution.

After the dissolved oxygen was removed by bubbling the above-mentioned monomer mixed solution with nitrogen gas for 20 minutes, the inside of the separable flask was replaced with nitrogen gas.
While stirring at a stirring speed of 0 rpm, the monomer mixture was heated using a water bath.

When the reflux liquid was confirmed in the cooling tube, 1,1-di (t-hexylperoxy) as a polymerization initiator was used.
0.03 g of -3,3,5-trimethylcyclohexane (manufactured by NOF CORPORATION, trade name: PerhexaTMH) was dissolved in 1 g of ethyl acetate, and charged to initiate boiling point polymerization. One hour after the start of the polymerization, a solution prepared by dissolving 0.05 g of perhexa TMH in 1 g of ethyl acetate was added again. Two hours, three hours, and four hours after the start of the polymerization, di- (3,5,5-trimethylhexanoyl) peroxide (trade name: Parloyl 355, manufactured by NOF Corporation) was added. 06 g, 0.3 g and 0.9 g dissolved in 1 g of ethyl acetate were added. The target acrylic copolymer solution was obtained by performing the boiling point polymerization for 7 hours. This acrylic copolymer was used as pressure-sensitive adhesive C. A protective tape was obtained in the same manner as in Example 3, except that the adhesive C solution was used instead of the adhesive B solution.

(Comparative Example 1) 90 g of ethyl acrylate
And a compound having a copolymerizable double bond and a peroxide bond in one molecule, t-butylperoxyallyl carbonate (trade name: Peromer AC, manufactured by NOF Corporation)
0 g and benzyl methyl ketal as a photopolymerization initiator (trade name: Irgacure 651 manufactured by Ciba Geigy)
0.1 g was obtained to obtain a monomer mixed solution.

The monomer mixed solution was bubbled with nitrogen gas for 20 minutes to remove dissolved oxygen. Thereafter, a weir was provided on the polyester film by a foam tape, a monomer mixed solution was poured into the weir, and another polyester film was laminated so as not to leave air therebetween.

Using a high-pressure mercury lamp, light having a wavelength of 365 nm was irradiated at an intensity of 17 mW for 60 minutes to complete the polymerization.
2 equipped with stirrer, cooler, thermometer and nitrogen gas inlet
After 80 g of the polybutyl acrylate obtained as described above was weighed and placed in an L-separable flask, 20 g of methyl methacrylate was added. Further, 100 g of ethyl acetate as a polymerization solvent was added so that the total solid content concentration became 50% by weight.

Using the polymer / monomer mixed solution obtained as described above, an acrylic copolymer was obtained in the same manner as in Example 1 below. This acrylic copolymer was used as pressure-sensitive adhesive D. Further, a protective film was obtained in the same manner as in Example 1, except that the above-mentioned pressure-sensitive adhesive D was used in place of the pressure-sensitive adhesive A.

Comparative Example 2 An adhesive D was obtained in the same manner as in Comparative Example 1. This adhesive D solution was added with N,
25 parts by weight of an isopropanol solution of N'-hexamethylene-1,6-bis (1-aziridine cardoxide) (solid content: 2% by weight) is added to 100 parts by weight of the acrylic copolymer, and mixed uniformly. After that, a polyester film (manufactured by Lintec Co., Ltd., product number: # 5011) formed into a 50 μm thick film that had been subjected to corona treatment in advance was coated so that the thickness after drying was 10 μm.
It was dried at a temperature of 110 ° C. for 5 minutes to obtain a protective tape.

Comparative Example 3 First, 300 g of ethyl acrylate, 75 g of methyl methacrylate, 123 g of ethyl acetate, and 12 g of toluene were placed in a 2 L separable flask equipped with a stirrer, a cooler, a thermometer and a nitrogen gas inlet.
3 g were obtained to obtain a monomer mixed solution. A protective tape was obtained in the same manner as in Example 4 except that this monomer mixed solution was used.

(Evaluation of Examples 1-4 and Comparative Examples 1-3)
For each of the protective tapes of Examples 1 to 4 and Comparative Examples 1 to 3 obtained as described above, the initial adhesive strength is as follows,
The adhesive strength with time, the adhesive strength at the time of oil contamination, and the weather resistance were evaluated.

The results are shown in Table 1 below. Initial adhesive strength: A protective tape was adhered to a SUS304 plate with a width of 25 mm according to JIS Z 0237.
After leaving at 20 ° C. for 20 minutes, the peeling force when peeling in the direction of 180 ° at a pulling speed of 300 mm / min was measured,
The initial adhesive strength was used.

経 時 Adhesive strength with time… Protective tape was made according to JIS
According to Z 0237, the plate was stuck to a SUS304 plate with a width of 25 mm, left at 23 ° C. for 20 minutes,
It was left at a constant temperature of 0 ° C. for one week, and then the peeling force when peeled in the direction of 180 ° at a pulling speed of 300 mm / min was measured and defined as the adhesive force with time.

... Adhesion at oil contamination ...
When bonded to a SUS304 plate with a width of 25 mm according to SZ0237, left at 23 ° C. for 20 minutes, immersed in cutting oil for 30 seconds, and then peeled in the 180 ° direction at a pulling speed of 300 mm / min. The peeling force of the oil was measured and determined as the adhesive force at the time of oil contamination.

Evaluation of light resistance and weather resistance: Each protective tape was manufactured according to JIS B 7753, using a sunshine weather meter (manufactured by Suga Test Instruments Co., Ltd., product number: WEL-SAN-H).
In C), light was irradiated for 200 hours, and peeled in the direction of 180 ° C. under a pulling speed of 300 mm / min, and the peeling force was measured. This peeling force was used as a guideline for evaluating light resistance and weather resistance.

In the column of the composition of the pressure-sensitive adhesive in Table 1,
When the structure of the copolymer and the olefin macromer are copolymerized, the abbreviation of the olefin macromer is shown.

[0078]

[Table 1]

As is clear from Table 1, in Comparative Examples 1 to 3, since the olefin macromer was not copolymerized,
In particular, in Comparative Example 1, glue residue occurred in all the evaluation methods. Also in Comparative Examples 2 and 3, adhesive residue was found in the evaluation of weather resistance. Further, in Comparative Example 2, the oil surface adhesive strength was as low as 30 g / 25 mm, and in Comparative Example 3,
It peeled off and did not exhibit oil surface adhesive strength.

On the other hand, in Examples 1 to 4, the acrylic copolymer obtained by copolymerizing the above-mentioned specific olefin macromer is used, so that only the initial adhesive strength and the temporal adhesive strength are excellent. And good results were also obtained in the evaluation of oil surface adhesion and light resistance / weather resistance.

Example 5 A separable flask equipped with a stirrer, a cooler, a thermometer and a nitrogen gas inlet was charged with 200 g of 2-ethylhexyl acrylate (2EHA) and methacrylated polystyrene at one end (manufactured by Sartomer Co., Ltd.).
Product name: Chemlink 4500, weight average molecular weight 1300
0) 60 g, lauryl mercaptan 0.1 g as a chain transfer agent, and ethyl acetate as a polymerization agent are blended,
This was a monomer mixed solution. The monomer mixed solution was bubbled with nitrogen gas for 20 minutes to remove dissolved oxygen. Then, the inside of the separable flask was replaced with nitrogen gas, and a water bath was used while stirring at 100 rpm. To raise the temperature of the monomer mixed solution. When the reflux liquid was confirmed in the cooling pipe, azobisisobutyronitrile as a polymerization initiator was added at 0.02 g every hour.
The polymerization reaction was performed dropwise for 6 hours to obtain an acrylic copolymer solution.

Thereafter, ethyl acetate was removed from the acrylic copolymer solution to obtain an acrylic copolymer (a). Separately, a separable flask equipped with a stirrer, a cooler, a thermometer and a nitrogen gas inlet is modified with 201 g of butyl acrylate (BA), 9.0 g of acrylic acid, and a radical polymerizable unsaturated double bond at the ends. 90 g of the obtained propylene polymer (ethylene glycol dimethacrylate-modified polypropylene, manufactured by Tonen Chemical Co., Ltd.) and 245.45 g of toluene as a polymerization solvent were blended to obtain a monomer mixed solution. After the dissolved oxygen was removed by bubbling this monomer mixed solution with nitrogen gas for 20 minutes, the inside of the separable flask was replaced with nitrogen gas, and
While stirring at a stirring rotation speed of rpm, the temperature of the monomer mixed solution was raised using a water bath. When the reflux liquid was confirmed in the cooling pipe, 1,1-di- as a polymerization initiator was used.
(T-hexylperoxy) -3,3,5-trimethylcyclohexane (trade name: Perhexa T, manufactured by NOF Corporation)
A solution prepared by dissolving 0.03 g of MH) in about 1 g of ethyl acetate was added to initiate boiling point polymerization. 1 after starting polymerization
After a lapse of time, a solution in which 0.05 g of perhexa TMH was dissolved in 1 g of ethyl acetate was added again. Also, 2 hours, 3 hours and 4 hours after the start of the polymerization,
(3,5,5-trimethylhexanoyl) peroxide (trade name: Parloyl 355, manufactured by NOF Corporation) 0.06
g, 0.30 g and 0.90 g were dissolved in 1 g of ethyl acetate, respectively. Boiling point polymerization was carried out for 7 hours to obtain an acrylic copolymer solution. Thereafter, the acrylic copolymer (b) was obtained by removing toluene from the acrylic copolymer solution.

A low-density polyethylene (trade name: Mirason 12 manufactured by Mitsui Petrochemical Co., Ltd.) was used as a support, and the acrylic copolymer (a) was used as a material for forming an adhesive layer. (B) was co-extruded as a material constituting the intermediate layer by a T-die method so as to be laminated in the order of support / intermediate layer / adhesive layer, and the thickness of the support was 50 μm and the thickness of the intermediate layer was 7 μm And a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer thickness of 5 μm.

(Comparative Example 4) An adhesive sheet was obtained in the same manner as in Example 1 except that the intermediate layer was not formed.

(Comparative Example 5) As a material constituting the intermediate layer, instead of the acrylic copolymer (b), an ethylene-methacrylic acid copolymer (trade name: Nucrel N1207C, manufactured by Mitsui Dupont Chemical Co., Ltd.) was used. Except having used it, it carried out similarly to Example 1, and obtained the adhesive sheet.

(Comparative Example 6) As a material constituting the intermediate layer, an ethylene-ethyl acrylate copolymer (manufactured by Nippon Unicar, trade name: NUC-FLXEEA DPDJ-6182) was used instead of the acrylic copolymer (b). A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that (1) was used.

(Evaluation of Example 5 and Comparative Examples 4 to 6) With respect to the pressure-sensitive adhesive tapes of Example 5 and Comparative Examples 4 to 6 obtained as described above, the initial adhesive force and the adhesive force with time were evaluated. The initial adhesive strength was evaluated in the same manner as in Examples 1-4. Further, regarding the adhesive strength over time, Example 1 was repeated except that it was left at 23 ° C. for 2 weeks.
The evaluation was performed in the same manner as in the evaluation of the adhesive strength over time at 23 ° C. In the evaluation of the initial adhesive strength and the temporal adhesive strength, the presence or absence of adhesive residue after peeling was visually evaluated. The evaluation results are shown in Table 2 below.

[0088]

[Table 2]

In Comparative Example 4, since the intermediate layer was not formed, the acrylic adhesive was not sufficiently adhered to the support made of low-density polyethylene. SUS304 after peeling
Glue residue occurred on the entire surface of the board.

In Comparative Examples 5 and 6, the acrylic pressure-sensitive adhesive composed of the acrylic copolymer (a) was used, probably because the intermediate layer, the ethylene-methacrylic acid copolymer and the ethylene-ethyl acrylate copolymer were used. Was not sufficiently adherent to the support, and an adhesive residue was generated in both the initial adhesive strength evaluation and the temporal adhesive strength evaluation.

On the other hand, in Example 5, the intermediate layer composed of the acrylic copolymer (b) was formed by the adhesive layer composed of the acrylic copolymer (a) and the support composed of the low-density polyethylene. Because it was co-extruded so as to be disposed between, because the acrylic pressure-sensitive adhesive layer was firmly adhered to the support made of low-density polyethylene, both the initial adhesive force and the adhesive force with time showed a sufficient value, and these No adhesive residue was generated after peeling in the evaluation of.

[0092]

In the acrylic pressure-sensitive adhesive tape or sheet according to the first aspect of the present invention, an olefin macromer (b) is copolymerized with an alkyl methacrylate (a) having an alkyl group having 1 to 14 carbon atoms. Since the pressure-sensitive adhesive layer is composed of an acrylic pressure-sensitive adhesive containing an acrylic copolymer, it is difficult for the adhesive force to decrease with time, for example, the adhesion increase after light irradiation with a sunshine weather meter is small, and the oil content is low. Even when adhered, peeling or the like hardly occurs. In addition, adhesive residue on the surface of the adherend during peeling hardly occurs, and therefore, contamination of the adherend hardly occurs.

Therefore, according to the first aspect of the present invention,
Provide a protective tape that has appropriate adhesive strength, exhibits good removability, has little adhesion enhancement due to aging or light irradiation, is excellent in light resistance and weather resistance, and is also excellent in oil resistance. It becomes possible.

In the acrylic pressure-sensitive adhesive tape or sheet according to the fourth aspect, the intermediate layer is made of the same material as the pressure-sensitive adhesive layer used in the acrylic pressure-sensitive adhesive tape or sheet according to the first aspect. It consists of
The base material and the acrylic pressure-sensitive adhesive layer are co-extruded and integrated via the intermediate layer. Therefore, similarly to the first aspect of the present invention, it is possible to provide an acrylic pressure-sensitive adhesive tape or sheet having excellent oil resistance, light resistance, and weather resistance.

Continued on front page F-term (reference) 4J004 AA10 AB01 CA03 CA04 CC02 CC03 4J027 AA08 BA02 BA03 BA04 BA05 BA06 BA07 BA08 BA10 BA12 BA13 BA15 CA02 CA03 CA09 CA10 CA14 CA25 CA28 CB03 CB10 CC05 CD09 4J040 DF041 DF051 MA06 MA09 MB09 NA12

Claims (4)

[Claims] 1. An acrylic copolymer obtained by copolymerizing a polymerizable composition containing an alkyl (meth) acrylate (a) having an alkyl group having 1 to 14 carbon atoms and an olefin macromer (b). Alternatively, an acrylic pressure-sensitive adhesive tape or sheet, wherein a pressure-sensitive adhesive layer comprising an acrylic pressure-sensitive adhesive composition containing the acrylic copolymer is laminated on one surface of a substrate. 2. The acrylic pressure-sensitive adhesive tape or sheet according to claim 1, wherein the base material is a polyolefin base material, and the pressure-sensitive adhesive layer is directly laminated on the polyolefin base material. 3. The acrylic pressure-sensitive adhesive tape or sheet according to claim 1, wherein the base material is a polyolefin base material, and the pressure-sensitive adhesive layer is laminated on the polyolefin base material via an intermediate layer. 4. An acrylic pressure-sensitive adhesive tape or sheet in which a polyolefin base material, an intermediate layer and an acrylic pressure-sensitive adhesive layer are coextruded and integrated, wherein the intermediate layer is
Alkyl (meth) having an alkyl group having 1 to 14 carbon atoms
Acrylic characterized by comprising an acrylic copolymer obtained by copolymerizing a polymerizable composition containing an acrylate (a) and an olefin macromer (b) or a composition containing the acrylic copolymer. Adhesive tape or sheet.