JPH11152457A - Acrylic self-adhesive tape or sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acrylic self-adhesive tape or sheet having good adhesiveness to adherends having oils adhered thereto and adherends having low polar surfaces and comprising polyolefin resins or the like. SOLUTION: This acrylic self-adhesive tape or sheet is obtained by laminating (B) an acrylic self-adhesive composition on one side of (A) a substrate comprising an acrylic polymer. The component B comprises an acrylic copolymer obtained by copolymerizing a polymerizable composition comprising (a) an alkyl (meth)acrylate and (b) an olefinic polymer having radically polymerizable unsaturated double bonds at the molecular terminals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an acrylic pressure-sensitive adhesive tape or sheet.

[0002]

2. Description of the Related Art With the technical progress of pressure-sensitive adhesives, the types of pressure-sensitive adhesive compositions have been diversified, and the range of application has been expanded. Conventionally, the fields of nailing, screwing, hooking, etc., and severe temperature and humidity conditions, etc. There is a demand for higher quality such as usage requirements for applications.

[0003] Acrylic copolymers have a tackiness per se and can be used in a wide range of fields as pressure-sensitive adhesives without the addition of tackifier resins. However, there has been a point that sufficient adhesion cannot be exhibited by itself with respect to an adherend having a low polarity surface made of polyethylene, polypropylene, or the like, or an adherend to which oil such as cutting oil has adhered. In particular, an acrylic pressure-sensitive adhesive composition in which the ratio of a monomer component containing a polar group such as a carboxyl group in an acrylic copolymer is increased in order to enhance the adhesive properties to an adherend having a polar surface such as a metal plate. However, the adhesive strength to the adherend having the low polarity surface is extremely reduced, and the function as a pressure-sensitive adhesive is lost.

As an attempt to enhance the adhesion of an acrylic copolymer to an adherend having a low polarity surface such as polyethylene or polypropylene, see, for example, JP-A-3-28158.
No. 7 discloses an acrylic pressure-sensitive adhesive composition comprising 100 to 100 parts by weight of an acrylic polymer and 50 to 100 parts by weight of a resin acid ester.

[0005] WO / 95/2003 discloses that
A polymer obtained by copolymerizing an ethylene-butylene macromonomer with an acrylic monomer as a main component,
It is disclosed as an adhesive for an adherend having a low polarity surface such as polyethylene or polypropylene. However, a double-sided pressure-sensitive adhesive tape using these pressure-sensitive adhesives and using a polyester-based film, paper, or the like as a base material has poor followability and adhesion to an adherend having an uneven surface. The double-sided pressure-sensitive adhesive tape using a polyolefin-based resin foam sheet or a urethane-based resin foam sheet as a base material for the purpose of enhancing the conformability to irregular surfaces and the adhesiveness has a sufficient adhesive strength due to the low strength of the base material. Cannot be expressed. By controlling the foaming degree or increasing the thickness of the foamed sheet in an attempt to increase the strength of the foamed sheet in the shearing direction, the conformability or adherence of the uneven surface is sacrificed, and olefins such as polyethylene and polypropylene are particularly sacrificed. In addition, there is a problem that sufficient adhesiveness to a surface contaminated with oil cannot be obtained.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned facts, and has as its object to provide a low-polarity surface made of an oil-adhered surface or a polyolefin resin such as polyethylene or polypropylene. An object of the present invention is to provide an acrylic pressure-sensitive adhesive tape or sheet having good adhesiveness to an adherend having a surface.

As a result of intensive studies on combinations of various base materials and pressure-sensitive adhesive compositions, the inventors of the present invention have found that acrylic monomers and a polymerizable olefin polymer are copolymerized on a base material made of an acrylic polymer. Obtained, the combination of the pressure-sensitive adhesive composition consisting of a specific acrylic copolymer,
The inventors have found that the above objects can be achieved, and have completed the present invention.

[0008]

The invention according to claim 1 (hereinafter referred to as "the present invention") comprises a step of forming a (meth) alkyl acrylate (a) on one surface of a base material (A) comprising an acrylic polymer.
And an acrylic pressure-sensitive adhesive composition (B) comprising an acrylic copolymer obtained by copolymerizing a polymerizable composition containing an olefin polymer (b) having a radically polymerizable unsaturated double bond at a terminal. Is an acrylic pressure-sensitive adhesive tape or sheet obtained by laminating the above.

The acrylic polymer used for the substrate (A) of the present invention comprises a polymerizable monomer component containing (meth) alkyl acrylate (a) as a main component. The (meth) alkyl acrylate (a) preferably has an alkyl group having 1 to 14 carbon atoms from the viewpoint of satisfying adhesiveness and toughness. For example, (meth) acrylic acid methyl ester, ethyl acrylate Esters, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate,
(Meth) acrylic acid sec-butyl ester, (meth)
T-butyl acrylate, cyclohexyl acrylate, n-octyl (meth) acrylate, isooctyl acrylate, 2-ethylhexyl (meth) acrylate, isononyl acrylate, lauryl (meth) acrylate ester,
Examples thereof include cetyl (meth) acrylate and stearyl (meth) acrylate. These alone,
Alternatively, two or more kinds may be used in combination.

The above (meth) alkyl acrylate (a)
The lower the content, the higher the rigidity of the obtained base material, the lower the conformability to the uneven surface and the lower the adhesiveness, and the higher the cohesive force, the more difficult it is to obtain sufficient shear strength. Medium, it is preferably 50 to 99% by weight, more preferably 80 to 95% by weight.

A vinyl monomer having a polar group may be added to the polymerizable monomer component. Examples of the vinyl monomer having a polar group include carboxyl group-containing vinyl monomers such as (meth) acrylic acid, itaconic acid, crotonic acid, (anhydride) maleic acid, fumaric acid, and carboxyethyl acrylate; 2-hydroxyethyl ( (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth)
Hydroxyl-containing vinyl monomers such as acrylate, caprolactone-modified (meth) acrylate, polyethylene glycol (meth) acrylate, and polypropylene glycol (meth) acrylate; (meth) acrylonitrile, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinyllaurillo Lactam, (meth) acryloylmorpholine, (meth) acrylamide, dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-butoxymethyl (meth) acrylamide,
Examples include nitrogen-containing vinyl monomers such as dimethylaminopropyl (meth) acrylamide, dimethylaminomethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and diethylaminoethyl (meth) acrylate.

When the content of the vinyl monomer component having a polar group is small, the cohesive strength is reduced, and it is difficult to obtain a sufficient shear strength. When the content is large, the rigidity of the obtained tape base material is increased, and In the polymerizable monomer component to reduce the properties and adhesion, preferably 1 to 50% by weight,
More preferably, it is 5 to 20% by weight.

In order to adjust the glass transition temperature and pressure-sensitive adhesiveness of the acrylic polymer, for example, styrene, α-
Monomers such as methylstyrene, o-methylstyrene, p-methylstyrene, and vinyl acetate may be added.

The acrylic polymer is obtained by polymerizing the polymerizable monomer component. Examples of the polymerization method include a solution polymerization method in which a thermal polymerization initiator is added and thermal polymerization is performed in a solution; A photopolymerization method in which a photoinitiator is added to the above polymerizable monomer in an inert gas to form a photopolymerizable monomer component, and a coating film of the photopolymerizable monomer component is irradiated with ultraviolet light to perform the method. The photopolymerization method is particularly preferred from the viewpoint that the performance of the substrate in the pressure-sensitive adhesive tape or sheet of the present invention can be easily imparted and productivity can be easily achieved.

The initiator (photopolymerization initiator) in the above-mentioned photopolymerization method is not particularly restricted but includes, for example, 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-
acetophenone-based polymerization initiators such as α, α′-dimethylacetophenone, methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone and 2,2-dimethoxy-2-cyclohexylacetophenone; benzoins such as benzoin ethyl ether and benzoin isopropyl ether Ether-based polymerization initiators; ketal-based polymerization initiators such as benzyldimethyl ketal; bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, halogenated ketones, acylphosphenoxides, acylphosphinates And the like.

If the amount of the photopolymerization initiator is too small, the polymerization reaction will not be completed and the polymer will have a strong monomer odor,
Further, when the amount increases, the amount of generated radicals increases, the molecular weight decreases, and it becomes difficult to sufficiently obtain the shear strength of the obtained acrylic polymer.
0.00 to 5 parts by weight, preferably 0.01 to 5 parts by weight,
More preferably, it is 0.05 to 3% by weight.

The acrylic polymer is further cross-linked by a cross-linking agent to further increase cohesion and impart sufficient shear strength to the adhesive fixation of a structure when used as a base material for an adhesive tape or sheet. Can be done. When the acrylic polymer is a photopolymerization method, by adding a polyfunctional (meth) acrylate as a cross-linking agent, the polymerizable monomer component is copolymerized at the time of polymerization and cross-linking can be performed.

Examples of the polyfunctional (meth) acrylate include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 1,9-nonanediol di (meth) acrylate. , (Poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, glycerin methacrylate acrylate, pentaerythritol tri (meth) Acrylate, trimethylolpropane tri (meth) acrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene,
Epoxy (meth) acrylate, polyester (meth)
Acrylate, urethane (meth) acrylate and the like can be mentioned. These may be used alone or in combination of two or more.

If the amount of the polyfunctional (meth) acrylate component is too small, a sufficient degree of crosslinking cannot be obtained, the cohesive strength decreases, and it becomes difficult to obtain sufficient heat resistance and shear strength.
Also, when the number increases, the crosslinking density increases and the flexibility is impaired,
Since the followability and adhesiveness of the resulting acrylic-based polymer-based sheet base material are reduced, the content is preferably 0.01 to 1 part by weight, preferably 0.02 to 0. 0 parts by weight, based on 100 parts by weight of the polymerizable monomer component. 8 parts by weight.

In addition to the polyfunctional (meth) acrylate, a general crosslinking agent capable of reacting with the polar group of the vinyl monomer having a polar group contained in the polymerizable monomer component is added, so that the By curing after polymerization, it is also possible to add a crosslink between the produced acrylic polymers. Examples of the general crosslinking agent include, for example, toluylene diisocyanate (TDI), naphthylene-1,5-diisocyanate, diphenylmethane diisocyanate (MDI), and hexamethylene diisocyanate (HMD).
I) isocyanate-based crosslinking agents such as isophorone diisocyanate (IPDI), xylene diisocyanate (XDI), and trimethylolpropane-modified TDI; ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether And the like; and an aziridine-based cross-linking agent such as N, N-hexamethylene-1,6-bis (1-aziridinecarboxamide). These may be used alone or in combination of two or more.

For the same reason as described above, the amount of the post-crosslinking agent to be added is based on 100 parts by weight of the polymerizable monomer component.
It is 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight. The polyfunctional (meth) acrylate and the post-crosslinking agent are
They may be used together.

The crosslinking degree of the acrylic polymer is 70
% By weight or more is preferred. By setting the degree of cross-linking to 70% by weight or more, the cohesive force of the acrylic polymer is further increased as described above, and high shear strength is obtained while maintaining conformability and adherence to the sheet substrate. Become. By having the flexibility and flexibility that can impart the above-mentioned uneven surface followability and adhesion together with high shear strength, it is possible to apply in fields where high adhesive strength is required when it is made into an adhesive tape or sheet. It can be used for a wide range of applications, such as exhibiting high adhesion strength to a surface contaminated with oil and a low surface energy adherend made of a polyolefin resin such as polyethylene or polypropylene.

The degree of crosslinking is determined by immersing the acrylic polymer in a good solvent such as ethyl acetate, toluene or tetrahydrofuran (THF), crosslinking and insolubilizing the acrylic polymer, filtering, drying, and drying the acrylic polymer. Measure the rate (%).

The above-mentioned filler is added for the purpose of enhancing the stress relaxation of the substrate (A) made of an acrylic polymer. The filler is not particularly limited, and examples thereof include fine particles or hollow fine particles having an average particle diameter of 0.2 to 200 μm, preferably 10 to 100 μm. Examples of the hollow fine particles include inorganic hollow fine particles such as glass balloons, alumina balloons, shirasu balloons, and fly ash balloons; organic hollow fine particles made of polymethyl methacrylate, acrylonitrile-vinylidene chloride copolymer, polystyrene, phenol resin, and the like;
Diatomaceous earth, porous fine particles such as porous silica; glass beads, silica beads, silica gel, alumina silica, fly ash, synthetic mica, and other inorganic fine particles; polymethyl methacrylate beads, polystyrene beads, nylon beads, styrene-acryl beads, Organic fine particles such as urethane beads, silicone beads, polyethylene beads, polypropylene beads, EVA (ethylene-vinyl acetate copolymer) beads, and ethyl polyacrylate beads; cubic alumina silica, glass flakes, glass fibers, and chain clay minerals No. These may be used alone or in combination of two or more.

The addition amount of the fine particles or hollow fine particles is 0.5 to 100 parts by weight of the polymerizable monomer component.
~ 175 parts by weight are preferred. More specifically, in the case of hollow fine particles having a specific gravity of less than 1, preferably 0.7 to 10 parts by weight, and in the case of hollow fine particles or organic fine particles having a specific gravity of about 1, preferably 10 to 60 parts by weight and specific gravity of 2 or more. The weight of such heavy inorganic fine particles is preferably 70 to 150 parts by weight.

In terms of volume fraction, the content is preferably 10 to 50% by volume based on the acrylic polymer. If the content is less than 10% by volume, it is difficult to obtain a high adhesive strength, and if the volume fraction exceeds 50% by volume, it is difficult to obtain a high shear strength.

The method for producing the base material (A) made of the acrylic polymer is not particularly limited as long as it includes a process of polymerizing the polymerizable composition containing the (meth) alkyl acrylate as a main component to form a film. Although not limited, for example, in the case of a photopolymerization method, the above (meth) alkyl acrylate, a vinyl monomer having a polar group,
A method of forming a coating film of a photopolymerizable composition comprising a photopolymerization initiator, a cross-linking agent and a filler into a sheet, irradiating the coating film with light, and polymerizing on a process paper, or the like.

As the light irradiation lamps in the photopolymerization method, those having an emission distribution at a light wavelength of 400 nm or less are used. For example, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultrahigh-pressure mercury lamps, chemical lamps, black lamps, and the like. A light lamp, a microwave excitation mercury lamp, a metal halide lamp, or the like is used. Above all, the chemical lamp efficiently emits light in the active wavelength region of the photopolymerization initiator, and the light absorption by the polymerizable composition components other than the photopolymerization initiator is small. It transmits light and is suitable for forming a thick sheet.

The irradiation intensity of the lamp is appropriately controlled for each property of a target product, and the degree of polymerization of the obtained polymer is adjusted to a predetermined range. For example, when a commonly used cleavable photopolymerization initiator having an acetophenone group is used, when the irradiation intensity is low, the time until the start of the reaction varies due to inhibition of polymerization by oxygen, and the polymerization degree is constant. Is difficult to obtain, and when it is high, the molecular weight of the obtained acrylic copolymer is reduced, so that it is difficult to balance the cohesive force and the stress relaxation property, so that a wavelength effective for photodecomposition of the photopolymerization initiator is obtained. Area (typically 365-420n
m of light are used. ) Is 0.1-100 mW
/ Cm2.

Radical polymerization such as the above-mentioned photopolymerization generally has a polymerization inhibition by oxygen, which is caused by oxygen in the air and oxygen dissolved in the photopolymerizable composition. For this reason, at the time of photopolymerization, a means for removing oxygen in the photopolymerization system is employed. As the oxygen removing means, for example, the coating film of the photopolymerizable composition is covered with a light transmissive cover film such as a surface-released polyethylene terephthalate film or a tetrafluoroethylene film, and light passes through the cover film. And irradiating the coating film of the photopolymerizable composition with an inert gas such as nitrogen gas or carbon dioxide gas, and then reacting in an inert box having a light-transmissive window in which oxygen is substituted.

The base material (A) made of the above-mentioned acrylic polymer has a thickness of 50%, because if it is too thin, the conformability to irregularities is lowered, and if it is too thick, the shear strength is lowered.
It is preferably about μm to 5 mm.

The acrylic pressure-sensitive adhesive composition (B) used in the present invention comprises an alkyl (meth) acrylate (a) and an olefin polymer (b) having a radically polymerizable unsaturated double bond at its terminal. A) a polymerizable composition comprising
It is composed of an acrylic copolymer obtained by copolymerization.

The above (meth) alkyl acrylate (a)
Examples thereof include those similar to those used for the above-mentioned acrylic polymer.

The above (meth) alkyl acrylate (a)
When the content is low, gelling of the obtained acrylic pressure-sensitive adhesive composition (B) is likely to occur, and when the content is high, the adhesive strength is reduced, and the adherend to which oil is adhered or a low-polarity surface such as polyethylene or polypropylene is adhered. Therefore, the copolymerization ratio in the acrylic copolymer is preferably 95 to 50% by weight, since it becomes difficult to obtain an adhesive force to an adherend having the following.

In order to adjust the glass transition temperature of the acrylic copolymer obtained and the adhesive strength of the acrylic pressure-sensitive adhesive composition (B), the (meth) alkyl acrylate (a) is used.
In addition, styrene, α-
Methylstyrene, o-methylstyrene, p-methylstyrene, esters of alkyl carboxylic acids and vinyl alcohol such as vinyl acetate, acrylic acid, methacrylic acid, vinyl carboxylic acids such as itaconic acid, maleic anhydride,
Vinyl carboxylic anhydride such as itaconic anhydride, hydroxyl group-containing vinyl monomer such as 2-hydroxyethyl (meth) acrylate, (meth) acrylonitrile,
A vinyl monomer such as a nitrogen-containing vinyl monomer such as N-vinylpyrrolidone and acryloylmorpholine may be added for use.

The above (meth) alkyl acrylate (a)
As the amount of the vinyl monomer added to the resin increases, the cohesive strength increases and the adhesive strength decreases.
Of all polymerizable components containing alkyl acrylate (a), 3
It is preferably 0% by weight or less.

The olefin polymer (b) having a radically polymerizable unsaturated double bond at a terminal used in the present invention
Is not particularly limited as long as it has a polymer structure consisting of a double bond copolymerizable with another polymerizable monomer at the terminal and an olefin main skeleton. Specific examples of the olefin main skeleton include, for example, an ethylene-butylene random copolymer and a propylene polymer. The radical polymerizable unsaturated double bond is not particularly limited, and examples thereof include a vinyl group, a (meth) acryloyl group, and an allyl group.

As the compound of which the main olefin skeleton is an ethylene-butylene random copolymer, "KRATON LIQUID Po" manufactured by Shell Chemical Co., Ltd.
lymer HPVM-1251 ". or,
Examples of the compound in which the olefin main skeleton has a propylene polymer include ethylene glycol dimethacrylate-modified polypropylene (manufactured by Tonen Chemical Co., Ltd.).

When the content of the olefin polymer (b) containing a radically polymerizable unsaturated double bond at the terminal is reduced, the resulting acrylic pressure-sensitive adhesive has an adhesive force to an adherend to which oil is adhered and a polyethylene It becomes difficult to obtain an adhesive force to an adherend having a low polarity surface such as or polypropylene, and the gelation of the pressure-sensitive adhesive solution tends to occur and the practicability is reduced, so that the copolymerization ratio in the acrylic copolymer is It is preferably from 5 to 50% by weight.

The means for polymerizing the acrylic copolymer may be the same as the above-mentioned method for polymerizing an acrylic polymer. Specifically, for example, a polymerizable monomer component containing the (meth) alkyl acrylate (a) and an olefin polymer (b) having a radical polymerizable unsaturated double bond at a terminal is added to an ethyl acetate or the like. Solvent-free liquid obtained by dissolving in a solvent and adding a polymerization initiator, or by adding a photopolymerization initiator and a polyfunctional (meth) acrylate and, if necessary, a tackifying resin to the polymerizable component. Bulk polymerization performed by applying the mixture to a tape substrate and irradiating the coating film of the photopolymerizable composition with ultraviolet light in an inert gas such as nitrogen.

The weight average molecular weight of the acrylic copolymer is preferably 10,000 to 4,000,000, more preferably 200,000 to 2,000,000. When the weight average molecular weight is less than 10,000, it becomes difficult to obtain an adhesive force to an adherend to which an oil adheres or an adherend having a low polarity surface such as polyethylene or polypropylene, and if it exceeds 4,000,000, the viscosity increases. This makes it difficult to handle at the time of manufacture and in the step of laminating the substrate on the substrate using the same, which lowers productivity.

In the acrylic pressure-sensitive adhesive composition (B) used in the present invention, a tackifying resin may be added to the acrylic copolymer, and a hydrogenated petroleum resin is particularly preferred as the tackifying resin. The hydrogenated petroleum resin is obtained by hydrogenating a C9 petroleum resin obtained by cationic polymerization of a C9 fraction obtained by cracking naphtha, or a C5 fraction or a C5 fraction mainly composed of cyclopentadiene. Is obtained by hydrogenating a C5 petroleum resin obtained by thermally polymerizing dicyclopentadiene derived from, and means an alicyclic petroleum resin. The C9 fraction contains α-methylstyrene, vinyltoluene, vinylxylene, propenylbenzene, indene, methylindene and the like as polymerizable components, and the C9 fraction is usually traded as a mixture of the above polymerizable components. You.

The hydrogenated petroleum resin has a number average molecular weight of 500
Preferred is a resin having a softening point of 60 to 150 ° C. and a hydrogenation rate of 100%, a so-called fully hydrogenated petroleum resin. As such a hydrogenated petroleum resin, for example, Arakawa Chemical Co., Ltd., trade name “Alcon P140” and the like are commercially available.

The amount of the hydrogenated petroleum resin is preferably 5 to 50 parts by weight based on 100 parts by weight of the acrylic copolymer. When the addition amount of the hydrogenated petroleum resin is less than 5 parts by weight, the adhesive strength to the adherend to which the oil is adhered or the adherend having a low polarity surface such as polyethylene or polypropylene is reduced. This is because the compatibility with the copolymer deteriorates and the stability of the acrylic pressure-sensitive adhesive composition decreases.

The acrylic pressure-sensitive adhesive composition (B) used in the present invention may contain a crosslinking agent in addition to the hydrogenated petroleum resin in order to improve cohesion. Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an aziridine-based crosslinking agent, and an epoxy-based crosslinking agent.

Further, if necessary, other additives such as tackifier resins, plasticizers, softeners, fillers, stabilizers, antioxidants, and colorants may be contained.

The acrylic pressure-sensitive adhesive composition obtained by adding a tackifier resin to the acrylic copolymer obtained by the above polymerization method, if necessary, is then applied to the substrate (A).
The acrylic pressure-sensitive adhesive tape or sheet of the present invention is prepared by lamination.

The thickness of the acrylic pressure-sensitive adhesive composition (B) is not particularly limited. For example, a liquid film is formed by a solution casting method, and the liquid film is irradiated with light such as ultraviolet rays. When the film is formed by
It can be manufactured in 5 mm.

The second aspect of the present invention provides the base material (A)
Is an acrylic polymer obtained by photopolymerizing a photopolymerizable composition comprising a (meth) alkyl acrylate, a vinyl monomer having a polar group, a photopolymerization initiator, a crosslinking agent, and a filler. The cohesive force is further increased, and high shear strength can be imparted to the acrylic copolymer sheet.

According to a third aspect of the present invention, the olefin main skeleton of the olefin polymer (b) having a radically polymerizable unsaturated double bond at a terminal is an ethylene-butylene random copolymer or a propylene polymer. Item 3. An acrylic pressure-sensitive adhesive tape or sheet according to item 1 or 2.

(Function) In the present invention, since an acrylic polymer is used as the base material (A), flexibility and flexibility capable of imparting conformability to an adherend and adherence to an adherend and high shear strength are provided. Is obtained. Further, a polymerizable composition containing (meth) alkyl acrylate (a) and an olefin polymer (b) having a radically polymerizable unsaturated double bond at a terminal is obtained by copolymerizing one surface of the base material. Acrylic pressure-sensitive adhesive composition (B) consisting of an acrylic copolymer to be used is laminated, so that an adherend to which oil is adhered or a low-polarity surface such as a polyolefin resin such as polyethylene or polypropylene is adhered. It shows high adhesive strength to the body. Therefore, it can be applied to fields requiring high adhesive strength, and can be used in a wide range of applications for types of adherends.

[0052]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the following examples. <Preparation of Acrylic Polymer Base Material (A)> Base material 1 850 parts by weight of 2-ethylhexyl acrylate (hereinafter abbreviated as 2EHA), 50 parts by weight of acrylic acid (hereinafter abbreviated as AAc), N-vinyl Pyrrolidone 100
Parts by weight, 2,2-dimethoxy-2-phenylacetophenone (trade name “IRGACURE 65” manufactured by Ciba Geigy)
1)) After stirring and mixing 3.0 parts by weight in a separable flask, the dissolved oxygen in the photopolymerizable monomer composition was reduced by bubbling the photopolymerizable monomer composition for 20 minutes using nitrogen gas. Removed. Thereafter, the photopolymerizable monomer composition was irradiated with ultraviolet rays using a black light lamp with stirring to partially polymerize the composition, thereby obtaining a partially polymerized product (a conversion rate of 4.0% and a viscosity of 4.0%). 2
400 cps).

To the partially polymerized photopolymerizable monomer composition, 0.2 part by weight of 1,6-hexanediol diacrylate (trade name “AHD” manufactured by Shin-Nakamura Chemical Co., Ltd.) was added.
On a release-treated PET film having a thickness of 38 μm, it is applied so that the thickness after polymerization is 1 mm, and a cover film made of a release-treated PET film having a thickness of 38 μm is further adhered onto the coating film. Laminated. The cover film surface was irradiated with ultraviolet light of 2 mW / cm 2 for 8 minutes using a chemical lamp for 8 minutes to further polymerize the partial polymer of the photopolymerizable monomer composition of the coating film, thereby forming an acrylic polymer sheet. (The residual monomer amount was 0.1% by weight or less, and the gel fraction was 95%.)

Substrate 2 850 parts by weight of 2EHA, 50 parts by weight of AAc, 100 parts by weight of N-vinylpyrrolidone, and 30 parts by weight of hydrophilic silica (trade name "Aerosil 200" manufactured by Nippon Aerosil Co., Ltd.) were rotated using a dissolver type stirrer. Several thousand rpm
With stirring for 4 hours, then 2,2-dimethoxy-2
-Phenylacetophenone (supra) 3.0 parts by weight and 1,6-hexanediol diacrylate (supra) 0.
Add 2 parts by weight to prepare a photopolymerizable monomer composition,
Thereafter, an acrylic polymer sheet having a thickness of 1 mm was prepared in the same manner as in the case of the base material 1 (the amount of the residual monomer was 0.1% by weight or less, and the gel fraction was 96%).

<Preparation of acrylic pressure-sensitive adhesive composition (B)> Acrylic pressure-sensitive adhesive composition-1 2EHA2 was placed in a 2-liter separable flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen gas inlet.
07g, AAc3g, ethylene-butylene random copolymer having a radical polymerizable unsaturated double bond at a terminal (trade name "KRATON LICU" manufactured by Shell Chemical Co., Ltd.)
ID Polymer HPVM-1251 ") 90g
Then, 122.73 g of ethyl acetate and 122.73 g of toluene were charged as a polymerization solvent, and nitrogen gas was bubbled into the monomer mixed solution for 20 minutes to replace dissolved oxygen and the inside of the separable flask system with nitrogen gas.

Then, the monomer mixture solution was heated with a water bath while stirring at 100 rpm with a stirrer, and when a reflux liquid was confirmed in a reflux condenser, a polymerization initiator (trade name, manufactured by NOF Corporation) "Perhexa T
MH ", 1,1-di (t-hexylperoxy) -3,
(3,5-trimethylcyclohexane) 0.03 g to 1 g
In ethyl acetate to initiate boiling point polymerization.

One hour after the start of the polymerization, the polymerization initiator 0.0
5 g was dissolved in 1 g of ethyl acetate and charged. After 2, 3 and 4 hours from the start of the polymerization, 1 g each of 0.06 g, 0.3 g and 0.9 g of di (3,5,5-trimethylhexanoyl) peroxide (trade name “Parloyl 355”, manufactured by NOF Corporation) And dissolved in ethyl acetate. Thus 7
Acrylic copolymer-1 was obtained by conducting the boiling point polymerization for one hour.
The weight average molecular weight (M
w) was 470,000 and the polydispersity (Mw / Mn) was 2.86.

The acrylic copolymer-1 has a solid content of 10
0 parts by weight of hydrogenated petroleum resin (Arakawa Chemical Industries,
(Product name "Alcon P140") 40 parts by weight of toluene 6
The mixture was stirred and mixed while being diluted with 0 parts by weight. Further, the crosslinking agent N, 100 parts by weight of the solid content of the acrylic copolymer was used.
15 parts by weight of an isopropanol solution (solid content 2% by weight) of N'-hexamethylene-1,6-bis (1-aziridine cardoxide) was stirred and mixed to obtain an acrylic pressure-sensitive adhesive composition-1.

Acrylic pressure-sensitive adhesive composition-2 The above acrylic copolymer was used except that 201 g of butyl acrylate (hereinafter abbreviated as BA) was used instead of 2EHA, and the amount of AAc was changed to 9 g. Acrylic copolymer-2 was prepared in the same manner as in 1. The weight average molecular weight (Mw) of the acrylic copolymer-2 was 41.2.
The polydispersity (Mw / Mn) was 2.71. A hydrogenated petroleum resin and a crosslinking agent were mixed in the same manner as in the acrylic pressure-sensitive adhesive composition-1 with respect to 100 parts by weight of the solid content of the acrylic copolymer-2, and the acrylic pressure-sensitive adhesive composition-2 was mixed.
I got

Acrylic pressure-sensitive adhesive composition-3 201 g of BA, 9 g of AAc, and a propylene polymer having a radical polymerizable unsaturated double bond at the terminal (manufactured by Tonen Kagaku Co., Ltd., a main skeleton of a propylene polymer, modified with ethylene glycol dimethacrylate) Acrylic copolymer-3 was prepared in the same manner as in the above acrylic copolymer-1 except that 90 g was used. The weight-average molecular weight (Mw) of the obtained acrylic copolymer-3 was 432,000,
The polydispersity (Mw / Mn) was 2.89. This copolymer-3 was used as an acrylic pressure-sensitive adhesive composition-3.

Acrylic pressure-sensitive adhesive composition-4 An acrylic copolymer was prepared except that the charged amount of 2EHA was 297 g and an ethylene-butylene random copolymer having a radically polymerizable unsaturated double bond at a terminal was not used. Acrylic copolymer-4 was prepared in the same manner as -1. A hydrogenated petroleum resin and a crosslinking agent were mixed with the acrylic copolymer-4 in the same manner as in the acrylic pressure-sensitive adhesive composition-1, to obtain an acrylic pressure-sensitive adhesive composition-4.

The acrylic copolymer-4 has a solid content of 10
0 parts by weight of hydrogenated petroleum resin (Alcon P140,
Acrylic pressure-sensitive adhesive composition-4 was obtained by mixing while diluting 40 parts by weight of Arakawa Chemical Industry Co., Ltd. with toluene.

(Examples 1 to 6, Comparative Examples 1 and 2) 1 m thick
An acrylic double-sided pressure-sensitive adhesive tape was prepared by combining a 50 μm-thick acrylic pressure-sensitive adhesive as shown in Table 1 with a substrate made of an acrylic polymer sheet of m. The acrylic pressure-sensitive adhesive layer was applied on release paper having a thickness of 95 μm so that the thickness after drying was 50 μm.
It was prepared by drying at a temperature of 0 ° C. for 5 minutes, transferred to the substrate and laminated.

In order to evaluate the performance of the acrylic pressure-sensitive adhesive tapes obtained in Examples 1 to 6 and Comparative Examples 1 and 2, a peeling force against a T-shaped stainless steel, a peeling force against an olefin at 90 ° and a peeling against an oil surface were evaluated. The force was evaluated by the following method. Table 1 shows the evaluation results.

(1. Stainless steel T-peeling force) A stainless steel foil of 0.05 mm × 25 mm × 100 mm (JIS SUS304, manufactured by Nippon Test Panel Co., Ltd., JIS) is provided on both sides of the obtained double-sided adhesive tape of 20 mm × 40 mm.
G 4305 standard product) in an environment of 23 ° C. and a relative humidity of 65%, and a 2 kg roller is reciprocated from the stainless steel foil at a speed of 300 mm / min.
After standing for 20 minutes in an environment at 65 ° C. and a relative humidity of 65%, a tensile speed of 20 in the same environment according to JIS K 6854.
A T-shaped peel test was performed at 0 mm / min to measure the peel strength.

(2. Peeling force against 90 ° olefin) The obtained double-sided pressure-sensitive adhesive tape having a size of 20 mm × 40 mm, which is lined with a polyester (PET) film having a thickness of 38 μm, is used as a test panel. 23 ° C, 65% relative humidity on polypropylene resin plate
Under the environment described above, and a 2 kg roller is reciprocated from the top of the PET film at a speed of 300 mm / min.
After leaving for 20 minutes in an environment of 3 ° C. and a relative humidity of 65%, a tensile speed of 3 in accordance with JIS Z 0237 under the same environment.
The film was peeled off at 90 mm / min in a 90 ° direction, and the peel strength was measured.

(3. Adhesion on oil surface) Obtained size 20 m
A rust-preventive oil was previously applied to both sides of a double-sided pressure-sensitive adhesive tape of mx 40 mm at a concentration of 6 g / m2 and left for one day.
mm × 25mm × 100mm stainless steel foil (see above)
And a 2 kg roller is reciprocated from the top of the stainless steel foil at a speed of 300 mm per minute by one reciprocation, and then left under an environment of 23 ° C. and a relative humidity of 65% for 20 minutes. According to JIS K 6854, tensile speed 200m
A T-peel test was performed at m / min to measure the peel strength.

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[Table 1]

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Since the present invention is constructed as described above, it has good adhesion to adherends having a low polarity surface such as olefinic resins and adherends to which oil has adhered. Is shown. Therefore, even building materials that are contaminated with oil such as rust-preventive oil or cutting oil, such as at a construction site, can be constructed without worrying about wiping off these oils. Significant reduction is possible. Further, since the pressure-sensitive adhesive tape of the present invention shows strong adhesiveness, it can be used in a wide range of industrial fields, including adherends having a low-polar surface such as the olefin-based resin and adherends to which oil has adhered, In particular, application in the structural adhesive field is possible.

Claims (3)

[Claims] 1. A substrate (A) comprising an acrylic polymer
An acrylic copolymer obtained by copolymerizing a (meth) alkyl acrylate (a) and a polymerizable composition containing an olefin polymer (b) having a radically polymerizable unsaturated double bond at a terminal. Acrylic pressure-sensitive adhesive composition (B) consisting of coalescing
Acrylic pressure-sensitive adhesive tapes or sheets characterized by being laminated. 2. A substrate (A) comprising an acrylic polymer
The acrylic pressure-sensitive adhesive tape according to claim 1, which is obtained by photopolymerizing a photopolymerizable composition comprising a (meth) alkyl acrylate, a vinyl monomer having a polar group, a photopolymerization initiator, a crosslinking agent, and a filler. Sheet. 3. The olefin main skeleton of the olefin polymer (b) having a radically polymerizable unsaturated double bond at the terminal is an ethylene-butylene random copolymer or a propylene polymer. The acrylic pressure-sensitive adhesive tape or sheet described in the above.