JP2000345123A - Non-silicone-based peelable substrate and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a non-silicone-based peelable substrate excellent in peelable properties to an adhesive surface, hardly causing problems such as electric contact defect caused by a silicone, and capable of leaving a large remaining adhesive force of the pressure-sensitive adhesive face after the peeling. SOLUTION: A film is formed by extruding a polyolefin-based resin composition comprising an acrylic copolymer having a long chain structural unit of the formula [CH2-C(R1)COOR2] (R1 is H or methyl; R2 is a 12-22C long chain alkyl) and an epoxy group-containing structural unit of the formula [CH2-C(R3) COOR4] (R3 is H or methyl; R4 is an alkyl having an epoxy group), and the obtained film is hardened by irradiating the acrylic copolymer at the surface part of the film with an ionizing radiation to provide the objective non-silicone- based peelable substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-silicone-based releasable base material and a method for producing the same, and more particularly, to an extruded film of a polyolefin-based resin composition or a laminate of the polyolefin-based resin composition and another base material. And a method for producing the same.

[0002]

2. Description of the Related Art Polyolefin films are required to be laminated with a single or other base material because of the good balance between physical and chemical properties and the ease of film forming.
It is used as a base for adhesive tape.
Further, as another use form consisting of the above-mentioned simple substance or a laminate, as a release agent, a silicone compound, a fluorine compound, a long-chain alkyl compound, a synthetic wax, or the like is contained in a polyolefin resin composition, It is also known to form a so-called releasable substrate in which the film itself is provided with a release function by film forming.

As one of such releasable substrates, Japanese Patent Application Laid-Open No. 5-140346 discloses that a polyolefin-based resin as a thermoplastic resin contains an organosiloxane, which is extruded and formed into a film. Then, the organosiloxane that bleeds on the film surface is cured by irradiation with radiation, and is fixed to the film surface, whereby the transfer of the organosiloxane to the adherend (adhesive surface such as adhesive tape) is prevented. Silicone-based releasable substrates have been proposed to prevent this.

[0004]

However, the above-mentioned conventional silicone-based releasable base material has excellent release performance on an adhesive surface, but has an unreacted material which does not take part in the curing reaction on the substrate surface (film surface). As a result of the presence of a trace amount of organosiloxane, which migrates to the adhesive surface, when this adhesive tape is used in recent high-density electronic component applications, problems such as defective electrical contacts may occur. Applications were limited.

In view of the above circumstances, the present invention provides a non-silicone coating which has excellent peeling performance on an adhesive surface, has no problems such as defective electrical contacts due to silicone, and has a large residual adhesive force on the adhesive surface after peeling. The purpose of the present invention is to obtain a non-removable base material.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, the polyolefin resin composition has a releasing agent other than the silicone compound, which contributes to the releasing performance. When a specific acrylic copolymer having an epoxy group involved in the curing reaction is included together with the long-chain alkyl group, this is extruded and formed into a film, which is then cured by irradiating it with ionizing radiation. In addition, it excels in peeling performance to the adhesive surface, and has essentially no problems such as defective electrical contacts due to silicone. In addition, the above-mentioned curing process allows the acrylic copolymer to be firmly fixed to the film surface. As a result, it was found that a non-silicon-based releasable base material having a large residual adhesive force on the pressure-sensitive adhesive surface after peeling was obtained.

The present invention has been completed on the basis of the above findings, and has the following formula (1):-[CH ₂ -C (R ¹ ) C
OOR ² ]-(wherein, R ¹ is hydrogen or a methyl group, R ²
Is a long-chain alkyl group having 12 to 22 carbon atoms) and a structural unit having a long-chain alkyl group represented by the formula (2):-[CH
_2- C (R ³ ) COOR ⁴ ]-(wherein, R ³ is hydrogen or a methyl group, and R ⁴ is an alkyl group containing an epoxy group). An extruded film of a polyolefin-based resin composition containing a copolymer or a non-silicone-based releasable substrate comprising a laminate of the film and another substrate.
This is related to 4).

Further, the present invention provides a method for producing the above-mentioned non-silicone-based peelable substrate, which comprises the formula (1):-[CH ₂ -C
A long-chain alkyl group-containing structural unit represented by (R ¹ ) COOR ² ]-(wherein R ¹ is hydrogen or a methyl group, and R ² is a long-chain alkyl group having 12 to 22 carbon atoms); (2); - ^{_{[CH 2 -C (R 3) COOR}} 4 ] - (wherein, R ³ is hydrogen or methyl, R ⁴ is an alkyl group containing an epoxy group) epoxy group-containing represented by After obtaining an extruded film using a polyolefin resin composition containing an acrylic copolymer having a structural unit, the acrylic copolymer on the surface of the film is cured by irradiation with ionizing radiation. According to a fifth aspect of the present invention, there is provided a method for producing a non-silicon-based peelable substrate.

Further, in the present invention, in obtaining the above-mentioned acrylic copolymer, the formula (1A); CH ₂ ＣC (R ¹ ) C
A long-chain alkyl group-containing monomer represented by OOR ² (wherein R ¹ is hydrogen or a methyl group, and R ² is a long-chain alkyl group having 12 to 22 carbon atoms); ₂ = C (R
³ ) COOR ⁴ (where R ³ is hydrogen or a methyl group, R
⁴ is an alkyl group containing an epoxy group), and a monomer mixture containing an epoxy group-containing monomer represented by the formula (1) is reacted with a polymerization initiator in the presence of a transition metal and its ligand using a polymerization initiator. The present invention relates to a method for producing a non-silicone-based releasable base material having the above-mentioned structure to obtain an acrylic copolymer by polymerization.

[0010]

Acrylic copolymer used in the Detailed Description of the Invention The present invention relates to compounds of formula (1); - [CH ₂ -C (R ¹⁾ C
OOR ² ]-(wherein, R ¹ is hydrogen or a methyl group, R ²
Is a long-chain alkyl group having 12 to 22 carbon atoms) and a structural unit having a long-chain alkyl group represented by the formula (2):-[CH
₂ -C (R ³⁾ COOR ^4] - (wherein, R ³ is hydrogen or methyl, R ⁴ is an alkyl group containing an epoxy group) and an epoxy group-containing structural unit represented by as essential components And if necessary, the formula (3);-[CH ₂
—C (R ⁵ ) CN] — (wherein, R ⁵ is hydrogen or a methyl group, and CN is a nitrile group). Such an acrylic copolymer can be synthesized by various known methods, but especially in the absence of a solvent or in the presence of a small amount of a solvent, without causing a safety problem, a living radical which can be advantageously carried out in the process. It is desirable to synthesize by a polymerization method.

The living radical polymerization method is described, for example, in (1) a report by Patten et al., “Radical Polymeri
zation Yielding Polymers with Mw / Mn 〜 1.05 by Hom
ogeneous Atom Transfer Radical Polymerization ”Po
lymer Preprinted, pp 575-6, No37 (March 1996),
(2) Report by Matyjasewski et al., “Controlled / Livi
ngRadical Polymerization. Halogen Atom Transfer Ra
dical Polymerization Promoted by a Cu (I) / Cu (II) Red
ox Process "Macromolecules 1995,28,7901-10 (Octob
er 15,1995), (3) same PCT / US96 / 03302, Inter
national Publication No. WO96 / 30421 (October
3, 1996), (4) Report by M. Sawamoto et al., “Ruthenium-me
diated Living Radical polymerization of Methyl Met
hacrylate "Macromolecules, 1996, 29, 1070.

The present inventors have focused on such a living radical polymerization method, using a transition metal and its ligand as an activator, and using a polymerization initiator in the presence of these to form a long-chain alkyl. By subjecting a monomer mixture containing a group-containing monomer and an epoxy group-containing monomer to living radical polymerization, a copolymer of the above-mentioned monomer mixture is formed. An acrylic copolymer having an alkyl group and an epoxy group involved in a curing reaction, that is, a long-chain alkyl group-containing structural unit represented by the formula (1) and an epoxy group-containing structural unit represented by the formula (2) In particular, by appropriately setting the polymerization order of the above-mentioned monomer mixture, the acrylic copolymer having the above constitution in which the above-mentioned monomers are polymerized in a block form can be easily produced. It found to be able to easily produce coalescence.

The above transition metals include Cu, Ru, F
There are e, Rh, V and Ni, and usually used from halides (chlorides, bromides, etc.) of these metals. The ligand is a ligand which coordinates with a transition metal as a center to form a complex, and a bipyridine derivative, a mercaptan derivative, a trifluorate derivative and the like are preferably used. Among the combinations of transition metals and their ligands, Cu ^{+ 1} -bipyridine complexes are most preferred in terms of polymerization stability and polymerization rate.

As the above-mentioned polymerization initiator, an ester or styrene derivative containing a halogen at the α-position is preferable, especially a 2-bromo (or chloro) propionic acid derivative, a chloride (or bromide) 1-derivative. Phenyl derivatives are preferably used. Specifically, methyl 2-bromo (or chloro) propionate, ethyl 2-bromo (or chloro) propionate, methyl 2-bromo (or chloro) -2-methylpropionate, 2-bromo (or chloro)- Ethyl 2-methylpropionate, 1-phenylethyl chloride (or bromide), ethylenebis (2
-Bromo-2-methylpropionate) and the like.

Further, the above-mentioned monomer mixture contains a monomer having a long-chain alkyl group as a main component, a monomer containing an epoxy group and, if necessary, a monomer containing a nitrile group and other modified monomers. As a monomer for use, an alkyl group having 12 carbon atoms
(Meth) acrylic acid alkyl ester, (meth) acrylamide, maleic acid mono- or diester, N, N-dimethylaminoethyl (meth) acrylate
And a mixture containing various monomers such as N, N-dimethylaminopropyl (meth) acrylate, N-vinylpyrrolidone, and (meth) acryloylmorpholine.

The long-chain alkyl group-containing monomer has the formula (1A):
A long-chain alkyl group represented by CH ₂ C (R ¹ ) COOR ² (wherein R ¹ is a hydrogen or methyl group, and R ² is a long-chain alkyl group having 12 to 22 carbon atoms) A) alkyl acrylate, for example, lauryl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate and the like. The amount of such a long-chain alkyl group-containing monomer used is 30% by weight in the monomer mixture.
As described above, usually 50 to 99.99% by weight, preferably 60%
The content is preferably up to 99.9% by weight. If the amount is too small, the peeling performance deteriorates.

The epoxy group-containing monomer is represented by the formula (2A): CH
(Meth) acrylic acid alkyl ester having an epoxy group represented by ₂ ＣC (R ³ ) COOR ⁴ (where R ³ is hydrogen or a methyl group, and R ⁴ is an alkyl group containing an epoxy group) is there. Specifically, glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth)
Acrylate and 6-methyl-3,4-epoxycyclohexylmethyl (meth) acrylate. The amount used is preferably from 40 to 0.01% by weight, and more preferably from 4 to 0.1% by weight in the monomer mixture. If the amount is too small, the curing will be insufficient. It is difficult to balance with the residual adhesive strength of the later adhesive surface.

The nitrile group-containing monomer is represented by the formula (3A): CH
₂ = C (R ⁵ ) CN (wherein R ⁵ is hydrogen or a methyl group and CN is a nitrile group), that is, acrylonitrile or methacrylonitrile. When this monomer is used, the heat resistance of the peelable substrate can be improved, probably because the cohesiveness of the obtained acrylic copolymer increases. The amount used is preferably such that the total amount of the above-mentioned other modifying monomers is less than 70% by weight, preferably 40% by weight or less in the monomer mixture. If the amount is too large, problems such as difficulty in achieving a balance between the peeling performance and the residual adhesive force of the adhesive surface after peeling are likely to occur.

In the living radical polymerization, the polymerization initiator is usually used in an amount of 0.0
It is used at a ratio of 1 to 10 mol%, preferably 0.1 to 2 mol%. Further, the amount of the transition metal used is in the form of a halide or the like, based on 1 mol of the above-mentioned polymerization initiator.
Usually, it is used at a ratio of 0.01 to 3 mol, preferably 0.1 to 1 mol. Further, the ligand is usually used in an amount of 1 mol per mol of the above transition metal (in the form of a halide or the like).
５5 mol, preferably 2-3 mol.
When the polymerization initiator and the activator are used in such a ratio, good results can be obtained in the reactivity of living radical polymerization, the molecular weight of the produced polymer, and the like.

Such a living radical polymerization can be carried out without a solvent, or may be carried out in the presence of a solvent such as butyl acetate, toluene and xylene.
When a solvent is used, it is preferable to use a small amount so that the concentration of the solvent after the completion of the polymerization becomes 50% by weight or less in order to prevent a decrease in the polymerization rate. By using no solvent or a small amount of solvent, good results can be obtained in terms of environmental health and safety. Further, the polymerization conditions are set to 70 from the viewpoint of the polymerization rate and the deactivation of the catalyst.
At a polymerization temperature of ~ 130 ° C, the polymerization time may be about 1-100 hours, depending on the final molecular weight and polymerization temperature.

The acrylic copolymer thus obtained is, as described above, a long chain represented by the formula (1) derived from the long chain alkyl group-containing monomer represented by the formula (1A) It has an epoxy group-containing structural unit represented by the formula (2) derived from the epoxy group-containing monomer represented by the formula (2A) as an essential component together with the alkyl group-containing structural unit. ) Having a nitrile group-containing structural unit represented by the formula (3) derived from the nitrile group-containing monomer represented by the formula (3), and further using a modifying monomer other than the above, It also has a structural unit derived from the body.

Particularly preferred as such an acrylic copolymer is one having an epoxy group-containing structural unit represented by the above formula (2) at the terminal or near the terminal of the molecular chain of the copolymer. is there. That is, by using the epoxy group-containing monomer represented by the above formula (2A), the above-mentioned epoxy group-containing structural unit is introduced at an arbitrary position in the molecular chain of the copolymer according to the time of addition of this monomer. Particularly, the above monomer is added at the latter stage of the polymerization, that is, the polymerization conversion is 8
When added at a point of time when the amount reaches 0% by weight or more, the above-mentioned epoxy group-containing structural unit can be introduced at or near the terminal end of the molecular chain of the copolymer, and an acrylic copolymer suitable for the present invention can be obtained. it can.

In the above living radical polymerization, it is desirable to use a polymerization initiator having an epoxy group in the molecule, since the epoxy group can be introduced into the starting terminal of the copolymer molecular chain. In particular, the epoxy group-containing monomer represented by the above formula (2A) is added at a later stage of polymerization to introduce the above-mentioned epoxy group-containing structural unit at or near the terminal end of the molecular chain of the copolymer. When an epoxy group is introduced at the start end of a copolymer molecular chain by using a polymerization initiator having an epoxy group in a molecule, two epoxy groups are telechelically introduced into the copolymer molecular chain. Become. According to such an acrylic copolymer, when it is crosslinked and cured, the copolymer molecular chain is extended more linearly, and a uniform crosslinked polymer with a small variation in the distance between crosslinks is generated, This is desirable because it gives a very good result on the balance between the peeling performance and the residual adhesive strength of the adhesive surface after peeling.

The polymerization initiator having an epoxy group in the molecule is an ester or styrene derivative having a halogen at the α-position and having an epoxy group in the molecule, and is a living radical polymerization. Can be used as long as it does not inhibit the progress of the reaction. Specifically, glycidyl 2-bromo (or chloro) propionate, glycidyl 2-bromo (or chloro) -2-methylpropionate, 3,4-epoxycyclohexylmethyl 2-bromo (or chloro) propionate, Bromo (or chloro) -2-methylpropionic acid 3,4
-Epoxycyclohexylmethyl and the like. These polymerization initiators having an epoxy group in the molecule may be used in combination with the polymerization initiator having no epoxy group in the molecule.In this case, if the total amount of both is within the above range, Good.

The acrylic copolymer used in the present invention has a number average molecular weight determined by GPC (gel permeation chromatography) in terms of polystyrene of usually from 1,000 to 500,000, preferably from 1,000 to 500,000. It should be in the range of 1,000 to 100,000. Such setting of the number average molecular weight can be easily performed by adjusting the charge ratio of the polymerization initiator and the monomer mixture, and by appropriately selecting the polymerization conditions in the living radical polymerization.

In the present invention, a polyolefin resin composition is prepared by incorporating the above-mentioned acrylic copolymer into a polyolefin resin. Here, the amount of the acrylic copolymer used is polyolefin resin 10
0.1 to 50 parts by weight, preferably 0.5 to 30 parts by weight, and more preferably 1 to 20 parts by weight with respect to 0 parts by weight. When the amount is less than 0.1 part by weight, the effect of imparting release performance to the polyolefin resin becomes poor,
On the other hand, if it exceeds 50 parts by weight, the effect of imparting the release performance is saturated, which is disadvantageous in terms of cost, and the inherent properties of the polyolefin-based resin may be impaired.

As the polyolefin resin used in the present invention, various resins known as thermoplastic polyolefins can be used. Specifically, low-density polyethylene,
Medium-density polyethylene, high-density polyethylene, copolymers of ethylene with small amounts of other α-olefins, polypropylene, random or block copolymers of propylene with small amounts of other α-olefins, copolymers of ethylene with vinyl acetate Polymers, mixtures thereof, and the like are included. Among these polyolefin resins, the density is 0.92 to 0.9.
6. It is desirable to use low density to high density polyethylene having an MFR (Melt Flow Rate) of 0.5 to 5 g / 10 minutes, polypropylene, or the like.

Such a polyolefin resin composition is formed into an extruded film and then irradiated with ionizing radiation to cure the acrylic copolymer in the resin composition. It is desirable to mix an onium salt-based curing catalyst as a photoreaction initiator or the like. At that time, an epoxy group-containing compound or a hydroxyl group-containing compound may be blended to promote or control the curing reaction.

The onium salt-based curing catalyst is ArN
^{_{2 + Q -, Y 3 S}} + Q - , or Y ₂ I ⁺ Q ^- In the formulas, A
r is an aryl group such as a bis (dodecylphenyl) group, Y
Is an alkyl group or an aryl group as described above, and Q ^- is B
^{_{F 4 -, PF 6 -,}} A s F 6 -, SbF 6 -, SbCl
Non-basic and nucleophilic anions such as ₆ ⁻ , HSO ₄ ⁻ , and Cl], a diazonium salt, a sulfonium salt, or an iodonium salt. The compounding amount is 0.0 parts by weight based on 100 parts by weight of the polyolefin resin.
The content is 1 to 20 parts by weight, preferably 0.1 to 5 parts by weight. If the amount is too small, the curability is poor. If the amount is too large, the peeling properties may be impaired.

The epoxy group-containing compound is a compound having one or more epoxy groups in a molecule, such as ethylene glycol diglycidyl ether, glycerin diglycidyl ether, vinylcyclohexenedionoxide, limonene. Dioxide, 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexylcarboxylate, bis- (3,4-epoxycyclohexyl) adipate and the like can be mentioned. The hydroxyl group-containing compound is a compound having two or more hydroxyl groups in a molecule and includes 2-ethyl-1,3-hexanediol and the like.

In the present invention, such a polyolefin resin composition is extruded by a conventional method.
An extruded film having a thickness of usually 5 to 100 μm is used.
Next, the above-mentioned acrylic copolymer bleeding out to the film surface portion is cured by irradiating ionizing radiation, that is, cross-linked and cured by using an epoxy group contained in the above-mentioned copolymer. As a result, the non-silicone-based releasable substrate of the present invention, which exhibits excellent release performance on the adhesive surface of the adhesive sheet, can be obtained. Since the above-mentioned acrylic copolymer functioning as a release agent is a non-silicone type, it does not have the problem of defective electrical contacts due to silicone as in the prior art. Since the coalesced product is firmly bonded to the film surface by the above curing reaction, there is little fear that this will transfer to the adhesive surface of the adhesive sheet and contaminate the adhesive surface. Has a large residual adhesive strength.

The ionizing radiation used in the above-mentioned curing reaction of the acrylic copolymer includes, for example, electron beams, ultraviolet rays, X-rays and γ-rays. Among them, when irradiating with an electron beam, the irradiation dose is usually 20 Mrad or less, preferably 3 to 10 Mrad. When irradiating with ultraviolet rays, an ultraviolet ray source such as a high-pressure mercury lamp, a low-pressure mercury lamp, or a metal halide lamp is used, and usually 20 mJ to 3 J /
Desirably, the irradiation amount is cm ² .

The non-silicone-based releasable base material of the present invention comprises, in addition to a single extruded film made of the polyolefin-based resin composition having the above constitution, a laminate of the extruded film and another type of base material. It may be one that is made into a body. For other types of substrates, the basis weight is usually 30 to 200 g
/ M ² kraft paper, woodfree paper, paper such as glassine paper, Ya polyethylene usually 10~200μm thickness, polypropylene, polyester, plastisol poke film made of polyamide, a basis weight of normally 5 to 50 g / m ² nonwoven A woven fabric or the like is used. In addition, it is desirable that these other kinds of base materials are laminated after the above-mentioned extruded film is obtained and before it is irradiated with ionizing radiation and cured.
In some cases, lamination may be performed after the above curing.

[0034]

EXAMPLES Examples of the present invention will be described below in more detail. The acrylic copolymers (1) to (3) used in the examples and the acrylic polymer (4) used in the comparative example
Are produced by the following Production Examples 1 to 3 and Comparative Production Example 1. In the following Examples and Comparative Examples, “parts” means “parts by weight”.

Production Example 1 In a four-necked flask equipped with a mechanical stirrer, a nitrogen inlet, a condenser, and a rubber septum, 25 g (77 mmol) of octadecyl acrylate was placed, and into this, 2,2'-
Bipyridine (3 g, 19.2 mmol) was added, and the system was purged with nitrogen. 920 mg of copper bromide in a nitrogen stream
(6.4 mmol) and the reaction was heated to 90 ° C.
As a polymerization initiator, ethylenebis (2-bromo-2-methylpropionate (hereinafter, referred to as “dichloromethane”) diluted in 2 ml of butyl acetate
The polymerization was started by adding 1.15 g (3.2 mmol) of EBMP, and polymerization was performed at 90 ° C. for 4 hours under a nitrogen stream.

Polymerization rate [using gas chromatography,
The area ratio of octadecyl acrylate to 2,2'-bipyridine at the start of polymerization (conversion rate So) was calculated, and the area ratio during polymerization (conversion rate St) was determined to obtain 1- (conversion rate St). / (Ratio defined by conversion ratio So)] is 80
%, And then 4.6 g of 3,4-epoxycyclohexylmethyl acrylate was added thereto (25 g).
Mmol) was added via a rubber septum and this was heated for an additional 12 hours. The obtained polymer was diluted with toluene to about 20% by weight, the catalyst was removed by filtration, and this toluene solution was added to 1 liter of cold acetone to obtain a white precipitate. Finally, the reprecipitate is dried to obtain an acrylic copolymer.
(1) was manufactured. This acrylic copolymer (1) has a number average molecular weight [Mn] of 9,200, a weight average molecular weight [Mw] of 12,300, and a polymer dispersity [Mw / M].
n] was 1.34.

Production Example 2 25 g (74 mmol) of octadecyl methacrylate was placed in a four-necked flask equipped with a mechanical stirrer, a nitrogen inlet, a condenser, and a rubber septum.
-Bipyridine (1.5 g, 9.6 mmol) was added to purge the system with nitrogen. 458 mg of copper bromide in a nitrogen stream
(3.2 mmol) and the reaction was heated to 90 ° C.
885 mg (3.2 mmol) of 3,4-epoxycyclohexylmethyl 2-bromo-2-methylpropionate diluted in 2 ml of butyl acetate was added as a polymerization initiator to initiate polymerization, and the mixture was heated at 90 ° C. for 2 hours under a nitrogen stream. Polymerized. After confirming that the polymerization rate is 80% or more,
4-epoxycyclohexylmethyl methacrylate
2 g (6.4 mmol) are added from the rubber septum,
This was heated for a further 6 hours. Hereinafter, in the same manner as in Production Example 1, an acrylic copolymer (2) was produced. This acrylic copolymer (2) has Mn of 8,400 and Mw of 1
3,900 and Mw / Mn was 1.66.

Production Example 3 25 g (77 mmol) of octadecyl acrylate and 5 g of acrylonitrile were placed in a four-necked flask equipped with a mechanical stirrer, a nitrogen inlet, a condenser, and a rubber septum.
(94 mmol), and 3 g (19.2 mmol) of 2,2'-bipyridine was added thereto, and the atmosphere in the system was replaced with nitrogen. Under a nitrogen stream, 920 mg (6.4 mmol) of copper bromide was added, and the reaction system was heated to 90 ° C., and 1.15 g of EBMP diluted with 2 ml of butyl acetate was used as a polymerization initiator.
(3.2 mmol) and the polymerization was started.
Polymerization was performed at 90 ° C. for 4 hours. After confirming that the conversion was 80% or more, 4.6 g (25 mmol) of 3,4-epoxycyclohexylmethyl acrylate was added from a rubber septum, and the mixture was further heated for 6 hours. Hereinafter, in the same manner as in Production Example 1, an acrylic copolymer
(3) was manufactured. This acrylic copolymer (3) has Mn of 10,100, Mw of 14,100, and Mw / Mn.
Was 1.40.

Comparative Production Example 1 The same initial charge composition and the same polymerization method as in Production Example 1 were used.
The addition of 3,4-epoxycyclohexylmethyl acrylate during the polymerization was omitted, and 90% of the initial charge composition was maintained.
Except for polymerizing at 12 ° C. for 12 hours, the same as in Production Example 1,
An acrylic polymer (4) was obtained. This acrylic polymer
(4) is that Mn is 9,400, Mw is 12,200,
Mw / Mn was 1.30.

Example 1 Low-density polyethylene (density: 0.930, MFR: 4.
0 g / 10 min) 100 parts of the acrylic copolymer (1) 3
"UV-9380C" made by Toshiba Silicone Co., Ltd.
(Iodonium salt curing catalyst) 0.5 part was added and mixed well to prepare a polyolefin resin composition. The polyolefin-based resin composition was extruded using an extruder equipped with a hopper equipped with a T die to obtain a film having a thickness of 80 μm. Next, from both sides of this extruded film, an electrodeless ultraviolet lamp (FUSIO) was used.
N Co., Ltd.), and irradiate ultraviolet rays at an irradiation amount of 100 mJ / cm ² to obtain an acrylic copolymer on the film surface.
By cross-linking and curing (1), a non-silicon-based peelable substrate was produced.

Example 2 Medium density polyethylene (density: 0.940, MFR: 2.
1 g / 10 min) 100 parts of acrylic copolymer (2) 1
0 parts, "UV-9380C" manufactured by Toshiba Silicone Co., Ltd.
(Iodonium salt-based curing catalyst) 0.5 part was added and mixed well to prepare a polyolefin-based resin composition. This polyolefin resin composition was extruded using an extruder equipped with a hopper equipped with a T-die to obtain a film having a thickness of 30 μm. Kraft paper (basis weight 80 g / m ² ) supplied from an unwinding roll was laminated on the extruded film using a compression roll. Next, an electron beam irradiation apparatus [“CB-1” manufactured by Iwasaki Electric Co., Ltd.] is applied to the laminated body.
50 "] to irradiate an electron beam at an irradiation dose of 5 megarads to crosslink and cure the acrylic copolymer (2) on the film surface, thereby forming a non-silicone-based release substrate. Produced.

Examples 3 to 10 To 100 parts of polyethylene shown in Table 1, the allyl copolymer shown in the table was added in the number of parts shown in the table.
Further, the onium salt-based curing catalyst 0.5
These were mixed well with or without adding parts to prepare eight kinds of polyolefin-based resin compositions. Using each of the polyolefin-based resin compositions, the curing method (type and amount of ionizing radiation) was changed as shown in Table 2, and the other kinds of base materials described in the table were laminated or laminated. Other than the above, 8
A variety of non-silicon based release substrates were prepared. Table 1
In the column of polyethylene, "low density PE" means the low density polyethylene used in Example 1, "medium density PE" means the medium density polyethylene used in Example 2, and further in the column of curing catalyst. "TASHFP"
Means triarylsulfonium hexafluorophosphate.

[0043]

[0044]

Comparative Example 1 The low-density polyethylene used in Example 1 was extruded in the same manner as in Example 1 without blending the acrylic copolymer and the curing catalyst, and the extruded polyethylene having a thickness of 80 μm was obtained. A molded film was obtained, and this was used as a non-silicone-based release substrate.

Comparative Example 2 A polyolefin resin composition was prepared by blending 10 parts of the acrylic polymer (4) with 100 parts of the medium-density polyethylene used in Example 2, and using this resin composition as an example. 1
In the same manner as in the above, a non-silicon-based release substrate was produced.

The above Examples 1 to 10 and Comparative Examples 1 and 2
Each of the non-silicon-based releasable substrates prepared in the above was subjected to a peeling test for an adhesive surface and a residual adhesive strength test after peeling (non-staining test for an adhesive surface) by the following methods.
The results of these tests were as shown in Table 3 below.

<Peeling test for adhesive surface> Non-silico
The peelable base material was cut to a width of 40 mm and a length of 120 mm, and a commercially available adhesive tape having a width of 19 mm [“Polyester Tape No. 31B” manufactured by Nitto Denko Corporation) was weighed 2 kg. -After reciprocating the roller one time, press the adhesive
It was left at 50 ° C. for 3 days under a load of 0 g / cm ² . Thereafter, the load was released, the temperature was returned to room temperature, and the adhesive tape was peeled off at 180 mm by a tensile tester at a speed of 300 mm / min, and the force required for the peeling was measured. If the measured value is too large, the rewinding force of the adhesive tape is increased, and the rewinding workability is deteriorated. Conversely, if the measured value is too small, the rewinding workability is deteriorated.

<Residual Adhesion Test After Peeling> A stainless steel (SUS-304) plate was sufficiently polished with water-resistant abrasive paper (No. 280) and washed. The adhesive tape after performing the above-mentioned peeling test was put on the polished and cleaned surface with a rubber roller weighing 2 kg.
The crucible was pressed back and forth once. After being left at room temperature for 30 minutes, the film was peeled off at 180 ° at a speed of 300 mm / min, and the force required for the peeling was measured. Separately, the adhesive strength So was measured in the same manner as described above, using the adhesive tape before the above-mentioned peelability test, that is, a commercially available adhesive tape as it was. From these measured values, the residual adhesive force of the adhesive surface after peeling was calculated as [Sr / So] × 100.
(%). The larger this value is, the larger the residual adhesive force is, and the more excellent the non-staining property of the adhesive surface is.

[0050]

As is clear from the results in Table 3 above, all of the non-silicone-based peelable substrates of Examples 1 to 10 have excellent peeling performance on the adhesive surface.
It can be seen that the residual adhesive strength of the adhesive surface after peeling is large.

On the other hand, the non-silicone-based releasable base material of Comparative Example 1 comprising a polyethylene film was inferior in the peeling performance to the adhesive surface, and the polyethylene contained an acrylic polymer having no epoxy group. The non-silicone-based peelable substrate of Comparative Example 2 made of a film was inferior in the residual adhesive force of the adhesive surface after peeling, and both exhibited both the peeling performance to the adhesive surface and the residual adhesive force of the adhesive surface after peeling. I cannot be satisfied.

[0053]

As described above, according to the present invention, a specific acrylic copolymer having a long-chain alkyl group which contributes to release performance and an epoxy group which participates in a curing reaction is contained in a polyolefin resin as a release agent. By extruding this into a film by extrusion molding and then curing the acrylic copolymer on the film surface by irradiation with ionizing radiation, it has excellent peeling performance on the adhesive surface, In addition, it is possible to provide a non-silicon-based releasable base material which has no problem such as defective electrical contact due to silicone and has a large residual adhesive force on the adhesive surface after peeling, and a method for producing the same.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B32B 31/30 B32B 31/30 4J004 C08F 4/06 C08F 4/06 4J015 4/40 4/40 4J100 220 / 12 220/12 220/32 220/32 C08J 5/18 CES C08J 5/18 CES 7/00 CEY 7/00 CEY 305 305 C08L 23/02 C08L 23/02 (72) Inventor Michiharu Yamamoto Ibaraki-shi, Osaka 1-1-2 Shimohozumi F-term in Nitto Denko Corporation (reference) 4F071 AA14 AA15 AA20 AA33 AC03 AC12 AC13 AE03 AH19 BA01 BB06 BC01 4F073 AA07 BA18 BA22 BB01 CA41 CA45 4F100 AK03A AK04 AK06 BA05A02A DG10 EH17A EJ081 EJ531 GB41 GB90 JK06 JL14 4F213 AA03 AA21E AD08 AD32 AG01 AG03 AH81 WA05 WA86 WB02 WE25 4J002 BB031 BB051 BB061 BB121 CD192 G J00 4J004 DA02 DB03 FA05 4J015 CA15 DA13 DA18 DA23 DA33 EA03 EA06 4J100 AL05P AL08Q AL10Q AM02R BC54Q CA04 CA05 FA03 JA57

Claims (8)

[Claims] 1. The formula (1):-[CH ₂ -C (R ¹ ) CO
OR ² ]-(wherein, R ¹ is hydrogen or a methyl group, and R ² is a long-chain alkyl group having 12 to 22 carbon atoms) and a structural unit having a long-chain alkyl group represented by the formula (2): − [CH ₂
-C (R ³ ) COOR ⁴ ]-(wherein R ³ is hydrogen or a methyl group, and R ⁴ is an alkyl group containing an epoxy group). Extruded film of polyolefin resin composition containing polymer or laminating this with other base materials
Non-silicone-based peelable substrate consisting of 2. The acrylic copolymer comprises, in addition to the long-chain alkyl group-containing structural unit represented by the formula (1) and the epoxy group-containing structural unit represented by the formula (2), a compound represented by the formula (3): − [CH
₂ -C (R ⁵⁾ CN] - non-silicone of claim 1 having (wherein, R ⁵ is hydrogen or methyl, CN is the nitrile group) a nitrile group-containing structural unit represented by - down -Based release substrate. 3. The non-silicone copolymer according to claim 1, wherein the acrylic copolymer has an epoxy group-containing structural unit represented by the formula (2) at the terminal or near the terminal of the molecular chain of the copolymer. Base material. 4. The non-silico resin according to claim 1, wherein the acrylic copolymer is used in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the polyolefin resin in the polyolefin resin composition. -Resin base material. 5. Formula (1):-[CH ₂ -C (R ¹ ) CO
OR ² ]-(wherein, R ¹ is hydrogen or a methyl group, and R ² is a long-chain alkyl group having 12 to 22 carbon atoms) and a structural unit having a long-chain alkyl group represented by the formula (2): − [CH ₂
-C (R ³ ) COOR ⁴ ]-(wherein R ³ is hydrogen or a methyl group, and R ⁴ is an alkyl group containing an epoxy group). An extruded film is obtained using a polyolefin resin composition containing a polymer, and then the acrylic copolymer on the surface of the film is cured by irradiating it with ionizing radiation. A method for producing a release-based base material. 6. A non-silicone-based releasable substrate according to claim 5, wherein an onium salt-based curing catalyst is blended together with the acrylic copolymer in the polyolefin-based resin composition to obtain an extruded film. Manufacturing method. 7. The non-silicone according to claim 5 or 6, wherein after obtaining the extruded film, before or after curing by irradiation with ionizing radiation, it is formed into a laminate with another kind of substrate. A method for producing a base peelable substrate. 8. An acrylic copolymer is obtained by the following formula (1A); CH ₂ ＣC (R ¹ ) COOR ² (wherein R ¹ is a hydrogen or methyl group, and R ² is a C 12 to C 22) A long-chain alkyl group-containing monomer represented by the formula (2A): CH ₂ ＣC (R ³ ) COOR ⁴ (wherein
R ³ is hydrogen or a methyl group, and R ⁴ is an alkyl group containing an epoxy group) in the presence of a transition metal and its ligand. The method for producing a non-silicone-based releasable substrate according to any one of claims 5 to 7, wherein an acrylic copolymer is obtained by performing living radical polymerization using a polymerization initiator.