JP6259726B2 - UV curable carrier tape - Google Patents

Description

The present invention relates to an ultraviolet curable carrier tape that can transfer a fragile material to a film or an adhesive, and can peel the fragile material without destroying it after the transfer.

In portable information terminals such as portable electronic notebooks and information terminals, an input device in which a transparent touch panel is mounted on a liquid crystal display element is used, and a resistive film type or a capacitive type touch panel is widely used. ing. The touch panel generally has a structure in which a patterned transparent conductive film and a glass with a transparent conductive film are separated by a gap.
As a method for producing a patterned transparent conductive film, a double-sided adhesive tape for temporarily fixing a transparent conductive film on which a conductive metal layer containing a metal or metal oxide such as indium oxide (ITO) containing tin is formed is used. There is a method of forming a conductive pattern by performing annealing, photolithography, and etching after fixing to a workbench via the substrate (for example, Patent Document 1).

Since the transparent conductive film is a fragile material when performing these treatments, a carrier tape or the like is used to move the transparent conductive film from the work table to the next work table.
The carrier tape is used for transferring a fragile material or the like to a film or an adhesive on a work table, and is peeled off after its role is finished.
Accordingly, the carrier tape is required to have an appropriate adhesive force for bonding the fragile material while being able to be peeled without destroying the fragile material.

As a conventional carrier tape, a general tape having an acrylic pressure-sensitive adhesive is used, but a transparent conductive film is attached to the carrier tape, transferred to the film or the pressure-sensitive adhesive, and the carrier tape having finished its role is peeled off. At that time, there is a problem of destroying a fine pattern or the like formed on the transparent conductive film.

Japanese Patent No. 4683164

An object of the present invention is to provide an ultraviolet curable carrier tape that can transfer a fragile material to a film or an adhesive, and can peel the fragile material without destroying it after the transfer.

The present invention is an ultraviolet curable carrier tape in which an ultraviolet curable pressure-sensitive adhesive layer is formed on at least one surface of a base film, and the arithmetic average roughness Ra of the adhesive surface of the ultraviolet curable pressure-sensitive adhesive layer is The ultraviolet curable carrier tape has a ten-point average roughness Rz of 10 nm or less and an adhesive surface of the ultraviolet curable pressure-sensitive adhesive layer of 100 nm or less.
The present invention is described in detail below.

The present inventors transfer conductive thin layers formed using indium oxide (ITO), silver nanowires, silver particles, and the like, and fragile materials such as fine patterns made using the same. In this case, an attempt was made to use an ultraviolet curable carrier tape as the carrier tape.
However, it has been found that a general ultraviolet curable carrier tape may damage a part of a fragile material.
The present inventors have found that the cause of the damage is that the surface of the adhesive surface of the ultraviolet curable carrier tape is rough, and the arithmetic average roughness of the adhesive surface of the adhesive layer of the ultraviolet curable carrier tape. By using an ultraviolet curable carrier tape having a smoothness of Ra of 10 nm or less and a ten-point average roughness Rz of the pressure-sensitive adhesive layer of 100 nm or less, a fragile material can be transferred to a film or a pressure-sensitive adhesive. It has been found that the fragile material can be peeled without being destroyed after the transfer, and the present invention has been completed.

In this specification, “arithmetic mean roughness Ra” is a value measured according to JIS B0601: 2001. For example, it can be measured by a surface scanning method using an optical interference microscope Wyko NT9300 manufactured by Veeco.

In the present specification, “ten-point average roughness Rz” means that the altitude of the peak from the highest peak to the fifth peak in the reference length L is Yp1, Yp2, Yp3, Yp4 and Yp5, and the deepest valley bottom. Means the value obtained by the following formula (1), where Yv1, Yv2, Yv3, Yv4, and Yv5 are the elevations of the valley bottom from the first to the fifth depth. The larger the value of “ten-point average roughness Rz”, the rougher the surface, and the smaller the value, the smoother the surface. For example, it can be measured by a surface scanning method using a light interference microscope Wyko NT9300 manufactured by Veeco in accordance with JIS B0601: 2001.

The ultraviolet curable carrier tape of the present invention has an ultraviolet curable pressure-sensitive adhesive layer (hereinafter also simply referred to as “pressure-sensitive adhesive layer”) on at least one surface of a substrate film.
As the pressure-sensitive adhesive layer, for example, an acrylic acid alkyl ester-based and / or methacrylic acid alkyl ester-based polymerizable polymer having a radical polymerizable unsaturated bond in the molecule, a radical polymerizable polyfunctional oligomer or monomer, And a main component of the UV curable pressure-sensitive adhesive containing a photopolymerization initiator as necessary.
In such a pressure-sensitive adhesive layer, the entire pressure-sensitive adhesive is uniformly and rapidly polymerized and cross-linked by irradiating with ultraviolet rays, so that the elastic modulus is significantly increased due to polymerization and curing, and the adhesive strength is greatly reduced. Can be easily peeled off.

The polymerizable polymer is prepared by, for example, previously synthesizing a (meth) acrylic polymer having a functional group in the molecule (hereinafter referred to as a functional group-containing (meth) acrylic polymer) and reacting with the functional group in the molecule. It can obtain by making it react with the compound (henceforth a functional group containing unsaturated compound) which has a functional group to perform and a radically polymerizable unsaturated bond.

The functional group-containing (meth) acrylic polymer is an acrylic having an alkyl group usually in the range of 2 to 18 as a polymer having adhesiveness at room temperature, as in the case of a general (meth) acrylic polymer. By copolymerizing an acid alkyl ester and / or methacrylic acid alkyl ester as a main monomer, a functional group-containing monomer, and, if necessary, another modifying monomer copolymerizable therewith by a conventional method It is obtained. The weight average molecular weight of the functional group-containing (meth) acrylic polymer is usually about 200,000 to 2,000,000.
In addition, a weight average molecular weight is the value measured as a polystyrene conversion molecular weight by GPC (Gel Permeation Chromatography: gel permeation chromatography) method.

Examples of the functional group-containing monomer include a carboxyl group-containing monomer such as acrylic acid and methacrylic acid; a hydroxyl group-containing monomer such as hydroxyethyl acrylate and hydroxyethyl methacrylate; and an epoxy group containing glycidyl acrylate and glycidyl methacrylate. Monomers; Isocyanate group-containing monomers such as isocyanate ethyl acrylate and isocyanate ethyl methacrylate; and amino group-containing monomers such as aminoethyl acrylate and aminoethyl methacrylate.
Examples of other modifying monomers that can be copolymerized include various monomers used in general (meth) acrylic polymers such as vinyl acetate, acrylonitrile, and styrene.

The functional group-containing unsaturated compound to be reacted with the functional group-containing (meth) acrylic polymer is the same as the functional group-containing monomer described above according to the functional group of the functional group-containing (meth) acrylic polymer. it can. For example, when the functional group of the functional group-containing (meth) acrylic polymer is a carboxyl group, an epoxy group-containing monomer or an isocyanate group-containing monomer is used, and when the functional group is a hydroxyl group, an isocyanate group-containing monomer is used. When the functional group is an epoxy group, a carboxyl group-containing monomer or an amide group-containing monomer such as acrylamide is used, and when the functional group is an amino group, an epoxy group-containing monomer is used.

The polymerization initiator used when synthesizing the functional group-containing (meth) acrylic polymer is not particularly limited. For example, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, t -Hexylperoxypivalate, t-butylperoxypivalate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexanoate, Examples include t-butyl peroxy-2-ethylhexanoate, t-butyl peroxyisobutyrate, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxylaurate, and the like. . Of these, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane and t-hexylperoxypivalate are preferable. In addition, the said polymerization initiator may be used independently and may use 2 or more types together.

The polyfunctional oligomer or monomer preferably has a molecular weight of 10,000 or less, and more preferably has a molecular weight of 5000 or less so that the three-dimensional network of the pressure-sensitive adhesive layer can be efficiently formed by heating or light irradiation. And the number of radically polymerizable unsaturated bonds in the molecule is 2 to 20. As such more preferred polyfunctional oligomers or monomers, for example, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate Or the above-mentioned methacrylates etc. are mentioned. Other examples include 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylate, and methacrylates similar to those described above. These polyfunctional oligomers or monomers may be used alone or in combination of two or more.

Examples of the photopolymerization initiator include those activated by irradiation with light having a wavelength of 250 to 800 nm. Examples of such a photopolymerization initiator include acetophenone derivative compounds such as methoxyacetophenone. Benzoin ether compounds such as benzoin propyl ether and benzoin isobutyl ether, ketal derivative compounds such as benzyldimethyl ketal and acetophenone diethyl ketal, phosphine oxide derivative compounds, bis (η5-cyclopentadienyl) titanocene derivative compounds , Benzophenone, Michler ketone, chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, α-hydroxycyclohexyl phenyl ketone, 2-hydroxymethylphenol Examples include photo radical polymerization initiators such as nylpropane. These photoinitiators may be used independently and 2 or more types may be used together.
When the photopolymerization initiator is used, it is preferably blended in an amount of 2 phr or more in order to prevent curing inhibition due to oxygen.

The pressure-sensitive adhesive layer may further contain a gas generating agent that generates gas when irradiated with ultraviolet rays. When the pressure-sensitive adhesive layer containing such a gas generating agent is irradiated with ultraviolet rays, the pressure-sensitive adhesive layer is cross-linked and cured to increase the elastic modulus of the entire pressure-sensitive adhesive layer, which is generated in such a hard pressure-sensitive adhesive layer. Since the gas is released from the pressure-sensitive adhesive layer to the adhesion interface and peels at least a part of the adhesion surface, the separation can be facilitated.
Although the said gas generating agent is not specifically limited, For example, an azide compound, an azo compound, a ketoprofen, a tetrazole compound etc. are mentioned. Of these, azo compounds are preferred because they are easily available.

For the purpose of adjusting the cohesive force as the pressure-sensitive adhesive, the pressure-sensitive adhesive layer is appropriately blended with various polyfunctional compounds blended in general pressure-sensitive adhesives such as isocyanate compounds, melamine compounds, and epoxy compounds. Also good. Moreover, well-known additives, such as a plasticizer, resin, surfactant, wax, and a fine particle filler, can also be added.

In the ultraviolet curable carrier tape of the present invention, the arithmetic average roughness Ra of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer is 10 nm or less.
When the arithmetic average roughness Ra of the adhesive surface of the pressure-sensitive adhesive layer does not satisfy the above range, when a fragile material is transferred to a film or a pressure-sensitive adhesive, the material is damaged, such as dents, and the function of the material is impaired.
The upper limit of the arithmetic average roughness Ra of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer is preferably 8.5 nm.
The lower limit of the arithmetic average roughness Ra of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer is not particularly limited, but the lower limit of the arithmetic average roughness Ra of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer is preferably 1 nm.

In the ultraviolet curable carrier tape of the present invention, the ten-point average roughness Rz of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer is 100 nm or less.
When the ten-point average roughness Rz of the adhesive surface of the pressure-sensitive adhesive layer does not satisfy the above range, when a fragile material is transferred to a film or a pressure-sensitive adhesive, the material is damaged, such as dents, and the function of the material is impaired. .
The upper limit of the ten-point average roughness Rz of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer is preferably 85 nm.
The lower limit of the ten-point average roughness Rz of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer is not particularly limited, but the lower limit of the ten-point average roughness Rz of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer is preferably 10 nm.

Although the thickness of the said adhesive layer is not specifically limited, It is preferable that the thickness at the time of drying is 5-30 micrometers from the workability | operativity at the time of handling.

In the pressure-sensitive adhesive layer, a preferable lower limit of the adhesive strength before ultraviolet irradiation is 1 N / 25 mm. If the adhesive strength is less than 1 N / 25 mm, a fragile material may not stick. A more preferable lower limit of the adhesive strength is 1.5 N / 25 mm.
In the present specification, “adhesive strength” means an adhesive strength measured by a 180 degree peel test measured in accordance with JIS Z0237.

In the pressure-sensitive adhesive layer, a preferable upper limit of the adhesive strength after ultraviolet irradiation is 0.5 N / 25 mm. If the adhesive strength exceeds 0.5 N / 25 mm, a fragile material may be damaged during peeling. A more preferable upper limit of the adhesive force is 0.1 N / 25 mm.

The base film is not particularly limited as long as it is a material that can transmit ultraviolet rays. Examples of the base film include a resin film.
Examples of the resin film include polyolefin resin films such as polyethylene films and polypropylene films, polyester resin films such as polyethylene terephthalate (PET) films and polyethylene naphthalate (PEN) films, and ethylene-vinyl acetate copolymers. , Modified olefin resin film such as ethylene-acrylic acid ester copolymer, polyvinyl chloride resin film, polyurethane resin film, cycloolefin polymer resin film, acrylic resin film, polycarbonate film, ABS (acrylonitrile-butadiene-styrene ) Resin film, polyamide film, polyurethane film, polyimide film and the like.

A preferable thickness of the base film is 50 to 150 μm. When the thickness of the base film is 50 μm or less, the tape after transferring the fragile material may be wrinkled or bent, and may be very difficult to handle. Although the upper limit of the thickness of the said base film is not specifically limited, A preferable upper limit is 150 micrometers.

The adhesive surface of the ultraviolet curable carrier tape of the present invention is separated from the adhesive layer in order to prevent the adhesive layer from sticking to another member or adhering dust before use. It is preferably protected by a peelable separator such as a mold film or release paper.
The release film is not particularly limited, and examples thereof include polyolefin resin films such as polyethylene films and polypropylene films, polyester resin films such as polyethylene terephthalate films, ethylene-vinyl acetate copolymer films, polyurethane resin films, and the like. It is done.
The release paper is not particularly limited, and examples thereof include a polyethylene laminate type, a glassine type, a supercalendered type, a clay coat type, and an aqueous resin coat type.
Among these, from the viewpoint of elastic modulus, heat resistance, and smoothness, a polyethylene laminate type release paper is suitable as the separator.
Moreover, it is preferable that the surface which contact | connects the adhesive layer of the said separator is given the mold release process.

The separator preferably has an arithmetic average roughness Ra of 10 nm or less on the surface in contact with the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer.
When the arithmetic average roughness Ra of the surface in contact with the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer does not satisfy the above range, the arithmetic average roughness of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer is inadequate when the bonding condition with the pressure-sensitive adhesive layer is inappropriate. Ra may exceed 10 nm.
The upper limit of the arithmetic average roughness Ra of the surface in contact with the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer is more preferably 8.5 nm. A more preferable upper limit of the arithmetic average roughness Ra is 7.5 nm.
The lower limit of the arithmetic average roughness Ra of the surface in contact with the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer is not particularly limited, but the lower limit of the arithmetic average roughness Ra of the surface in contact with the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer is preferably 1 nm.

The separator preferably has a 10-point average roughness Rz of 200 nm or less on the surface in contact with the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer.
When the ten-point average roughness Rz of the surface in contact with the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer does not satisfy the above range, if the bonding condition with the pressure-sensitive adhesive layer is inappropriate, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer has ten points. The average roughness Rz may exceed 100 nm.
The upper limit of the ten-point average roughness Rz of the surface in contact with the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer is more preferably 150 nm.
The lower limit of the ten-point average roughness Rz of the surface in contact with the adhesive surface of the pressure-sensitive adhesive layer is not particularly limited, but the lower limit of the ten-point average roughness Rz of the surface in contact with the adhesive surface of the pressure-sensitive adhesive layer is 10 nm. preferable.

The preferable lower limit of the thickness of the separator is 1 μm, and the preferable upper limit is 500 μm. When the thickness of the separator is less than 1 μm, it may be difficult to peel off. When the thickness of the separator exceeds 500 μm, the thickness of the carrier tape with a separator may be unnecessarily thick. The more preferable lower limit of the thickness of the separator is 10 μm, and the more preferable upper limit is 150 μm.

As a method for producing the ultraviolet curable carrier tape of the present invention, for example, a solvent is added to the polymerizable polymer, the polyfunctional oligomer or monomer, and the photopolymerizable initiator, and a gas generating agent or the like as necessary. The additive for the pressure sensitive adhesive layer was further added to prepare a composition for the pressure sensitive adhesive layer, and this composition for the pressure sensitive adhesive layer was applied to one surface of the base film, and the solvent in the composition for the pressure sensitive adhesive layer was completely removed by drying. And a method for forming a pressure-sensitive adhesive layer. Moreover, when sticking a separator on the formed adhesive layer, the method of superimposing in the state in which the mold release process surface opposed the adhesive layer is mentioned.
Moreover, the said adhesive layer composition is apply | coated to the separator surface by which the mold release process was carried out so that arithmetic mean roughness Ra and ten-point average roughness Rz might become a predetermined range, There is also a method in which the solvent is completely removed by drying to form a pressure-sensitive adhesive layer, and then a base film is attached on the formed pressure-sensitive adhesive layer.
As a method for applying the pressure-sensitive adhesive layer composition, a knife coater or an applicator is generally used as long as the amount is small. In the case of continuous coating, generally three reverse coaters, direct gravure coaters, direct bar coaters, bar reverse coaters, die coaters and the like are preferably used.

As a method for adjusting the arithmetic average roughness Ra and ten-point average roughness Rz of the pressure-sensitive adhesive layer to the above-described ranges, a method for adjusting the coating conditions and drying conditions of the pressure-sensitive adhesive layer composition, Examples thereof include a method of suppressing the arithmetic average roughness Ra and the ten-point average roughness Rz of the separator surface in contact with the adhesive surface of the adhesive layer to the arithmetic average roughness Ra and the ten-point average roughness Rz of the adhesive layer.
Especially, since it is easy to adjust to a desired surface roughness, the method of suppressing the roughness of the separator surface which touches the adhesive surface of the said adhesive layer to the arithmetic mean roughness Ra of the adhesive layer and the ten-point average roughness Rz or less Is preferred.

By using the ultraviolet curable carrier tape of the present invention, a fragile material can be transferred to a film or an adhesive, and after the transfer, the fragile material can be peeled without being destroyed.
An example of a method for transferring a fragile material formed on a support to an adhesive layer using the ultraviolet curable carrier tape of the present invention is shown in FIGS.
Hereinafter, the present invention will be described in detail with reference to FIGS.

First, as shown in FIG. 1A, the ultraviolet curable pressure-sensitive adhesive layer 2 of the ultraviolet curable carrier tape 7 of the present invention is attached to a fragile material 3 formed on a support 4.
Next, as shown in FIG. 1B, the fragile material 3 is peeled off from the support 4 and held on the ultraviolet curable pressure-sensitive adhesive layer 2 of the ultraviolet curable carrier tape 7 of the present invention.

The fragile material 3 is not particularly limited as long as it is a material used in this application, and examples thereof include a thin film, a thin glass, and a transparent conductive layer alone.
Examples of the thin film include films made of polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polycarbonate resins, norbornene resins (COP, COC), and polyimide resins. Especially, the film which consists of PET is common.
The said thin layer glass is not specifically limited, For example, alkali glass, non-alkali glass, etc. are mentioned.
Examples of the metal constituting the transparent conductive layer include metals such as gold, silver, and copper, metal oxides such as indium oxide, zinc oxide, tin oxide, and titanium oxide, and nanowires, nanoparticles, and metals made of these. A mesh etc. are mentioned.

Next, as shown in FIG. 2A, the fragile material 3 held on the ultraviolet curable pressure-sensitive adhesive layer 2 of the ultraviolet curable carrier tape 7 of the present invention is formed on the transparent substrate 6. Affix to layer 5.
Further, as shown in FIG. 2 (b), the ultraviolet curable pressure-sensitive adhesive layer 2 is cured by irradiating the ultraviolet ray 8 from the base film 1 of the ultraviolet curable carrier tape 7 of the present invention, thereby causing an adhesive force. Reduce.

Although the said adhesive layer 5 is not specifically limited, For example, the transparent adhesive called OCA, OCR, etc., or the material which can adhere | attach etc. are mentioned.
Although the said transparent substrate 6 is not specifically limited, For example, plastic substrates, such as glass, a polycarbonate, a polystyrene, an acryl, etc. are mentioned.

The ultraviolet irradiation may be spot irradiation or entire surface irradiation.
A preferred lower limit of the irradiation intensity of the ultraviolet rays 1 mW / cm ^2, a preferred upper limit is 20,000 MW / cm ^2. If the irradiation intensity of the ultraviolet rays is less than 1 mW / cm ² , reliable peeling may not be performed even if the irradiation time is extended, and if it exceeds 20000 mW / cm ² , the cost required for the irradiation apparatus or the like increases significantly. Not realistic. Considering the cost and the like, it is considered that the actual upper limit is about 5000 mW / cm ² in an actual production site.
Although the irradiation time of the said ultraviolet-ray changes with irradiation intensity | strength, a preferable minimum is 1 second and a preferable upper limit is 200 seconds.

Thereafter, as shown in FIG. 3, the ultraviolet curable carrier tape 7 of the present invention in which the ultraviolet curable pressure-sensitive adhesive layer 2 is cured and the adhesive strength is reduced is peeled from the fragile material 3. Thereby, the fragile material 3 can be transferred to the pressure-sensitive adhesive layer 5.

ADVANTAGE OF THE INVENTION According to this invention, the ultraviolet curable carrier tape which can transfer a fragile material to a film or an adhesive, and can peel, without destroying this fragile material after transferring can be provided.

FIG. 1A is a schematic view showing an example of the fragile material 3 formed on the ultraviolet curable carrier tape 7 and the support 4 of the present invention, and FIG. 1B is the ultraviolet curable composition of the present invention. It is a schematic diagram which shows an example by which the weak material 3 was hold | maintained on the ultraviolet curable adhesive layer 2 of the type | mold carrier tape 7. FIG. FIG. 2A is a schematic diagram showing an example in which the fragile material 3 held in the ultraviolet curable pressure-sensitive adhesive layer 2 of the ultraviolet curable carrier tape 7 of the present invention is attached to the pressure-sensitive adhesive layer 5. (B) is a schematic diagram which shows an example which irradiates the ultraviolet-ray 8 from the base film 1 of the ultraviolet curable carrier tape 7 of this invention. It is a schematic diagram which shows an example which peels the ultraviolet curing carrier tape 7 of this invention from the weak material 3. FIG.

Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
<Preparation of composition for pressure-sensitive adhesive layer>
A reactor equipped with a thermometer, a stirrer, and a cooling tube was prepared. In this reactor, 94 parts by weight of 2-ethylhexyl acrylate, 1 part by weight of acrylic acid, 5 parts by weight of 2-hydroxyethyl acrylate, 0.01% lauryl mercaptan After adding parts by weight and 80 parts by weight of ethyl acetate, the reactor was heated to start refluxing. Subsequently, 0.01 parts by weight of 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane was added as a polymerization initiator in the reactor, and polymerization was started under reflux. It was. Next, after 1 hour and 2 hours from the start of polymerization, 0.01 parts by weight of 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane was added, and the polymerization was started. 4 hours later, 0.05 part by weight of t-hexylperoxypivalate was added to continue the polymerization reaction. And 8 hours after the start of polymerization, a functional group-containing acrylic polymer having a solid content of 55% by weight and a weight average molecular weight of 600,000 was obtained.

To 100 parts by weight of the resin solid content of the ethyl acetate solution containing the functional group-containing acrylic polymer, 3.5 parts by weight of 2-isocyanatoethyl methacrylate was added and reacted, and further, the ethyl acetate solution after the reaction 1 part by weight of photopolymerization initiator (Esacure One, manufactured by Nippon Shibel Hegner), silicone compound having a (meth) acrylic group (manufactured by Daicel Cytec, EBECRYL 350, acrylic equivalent is 2) 0.5 parts by weight of polyisocyanate crosslinking agent (Coronate L45, manufactured by Nippon Polyurethane Co., Ltd.) was mixed.
Thereafter, 100 parts by weight of 2,2-azobis- (N-butyl-2-methylpropionamide) is mixed with 100 parts by weight of the resin solid content of the solution, and the composition for the pressure-sensitive adhesive layer contains an azo compound. A product was prepared.

<Production of carrier tape>
The composition for the pressure-sensitive adhesive layer obtained above was dried on one side of a transparent PET film (separator) that was 75 μm thick and was subjected to release treatment with the surface roughness (Ra, Rz) described in Table 1. Coating was performed with a doctor knife so that the thickness was 10 μm, and the coating solution was dried by heating at 110 ° C. for 5 minutes to obtain an adhesive layer. The pressure-sensitive adhesive layer after drying showed adhesiveness in a dry state. Next, a 75 μm PET film (base film) was attached to the other surface of the pressure-sensitive adhesive layer. Thereafter, static curing was performed at 40 ° C. for 3 days to obtain a carrier tape having a total thickness of 85 μm and a surface roughness (Ra, Rz) of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer described in Table 1.
The surface roughness (Ra) is evaluated by a surface scanning method using an optical interference microscope Wyko NT9300 manufactured by Veeco, and the surface roughness (Rz) is a surface scanning method using an optical interference microscope Wyko NT9300 manufactured by Veeco. It was evaluated by.

(Example 2)
An ultraviolet curable carrier tape was prepared in the same manner as in Example 1 except that the surface roughness (Ra, Rz) of the adhesive surface of the adhesive layer was changed to the value described in Table 1 using the separator described in Table 1. did.

(Comparative Examples 1, 3-5)
An ultraviolet curable carrier tape was prepared in the same manner as in Example 1 except that the surface roughness (Ra, Rz) of the adhesive surface of the adhesive layer was changed to the value described in Table 1 using the separator described in Table 1. did.

(Comparative Example 2)
An ultraviolet curable carrier tape was prepared in the same manner as in Example 2 except that the surface roughness (Ra, Rz) of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer was changed to the value described in Table 1 using the separator described in Table 1. did.

<Evaluation>
The following evaluation was performed about the ultraviolet curable carrier tape obtained in Examples 1-2 and Comparative Examples 1-5. The results are shown in Table 1.

(Adhesive strength evaluation)
About the ultraviolet curable carrier tape obtained in Examples 1-2 and Comparative Examples 1-5, the adhesive strength before ultraviolet irradiation, and 365 nm using an ultrahigh pressure mercury lamp from the base film side of the ultraviolet curable carrier tape. The adhesive strength after irradiating the upper surface of the base film with an irradiation intensity of 50 mW / cm ² for 2 minutes was measured by 180 ° peeling according to JIS Z0237.

(Appearance evaluation of transparent conductive layer after transfer)
Using the ultraviolet curable carrier tapes obtained in Examples 1 and 2 and Comparative Examples 1 to 5, the transparent conductive layer was transferred to the adhesive layer by the following method, and the appearance of the transparent conductive layer after the transfer was observed with an optical microscope. Was observed and evaluated.
The transparent conductive layer and the pressure-sensitive adhesive layer used for the appearance evaluation of the transparent conductive layer after the transfer were produced by the following method.
<Method for producing transparent conductive layer>
Using a transparent polyethylene terephthalate (PET) film having a release treatment of 100 μm thickness on the support, conductive ink (silver paste) was printed on the release-treated surface to obtain a transparent conductive layer.
<Method for producing pressure-sensitive adhesive layer>
Using a non-alkali glass having a thickness of 0.7 mm as a transparent substrate, a 75 μm-thick transparent adhesive tape (Sekisui Chemical Co., Ltd., OCA 7622-75) is pasted on one surface of the transparent substrate using a 2 kg roller. The pressure-sensitive adhesive layer was produced by placing it at 5 kg / cm ² and 40 ° C. for 30 minutes using an autoclave.

<Method of transferring transparent conductive layer to pressure-sensitive adhesive layer>
The ultraviolet curable carrier tape obtained in Examples 1-2 and Comparative Examples 1-5 was applied to the transparent conductive layer obtained by the above method using an iron roll having a surface roughness Ra of 5 nm or less. Pasting was performed at a speed of 1 m / min.
Next, the transparent conductive layer attached to the ultraviolet curable carrier tape is attached to the adhesive layer formed on the transparent substrate by the above method using a 2 kg roller, and 5 kg / cm ² at 40 ° C. using an autoclave. Placed under conditions for 30 minutes.
Then, using an ultra-high pressure mercury lamp from the base film side of the UV curable carrier tape, 365 nm UV light is irradiated for 2 minutes while adjusting the illuminance so that the irradiation intensity on the upper surface of the base film is 50 mW / cm ^2. The carrier tape was peeled off at a rate of / min.

In the ultraviolet curable carrier tape obtained in Examples 1 and 2, the carrier tape could be easily peeled by hand after the ultraviolet irradiation. Further, the transparent conductive layer did not peel from the pressure-sensitive adhesive layer, and the conductive ink was not destroyed.
Even in the ultraviolet curable carrier tapes obtained in Comparative Examples 1 to 5, the carrier tape could be easily peeled by hand after the ultraviolet irradiation, and the transparent conductive layer was not peeled from the pressure-sensitive adhesive layer. However, dents were observed in a part of the conductive ink after peeling off the carrier tape.

ADVANTAGE OF THE INVENTION According to this invention, the ultraviolet curable carrier tape which can transfer a fragile material to a film or an adhesive, and can peel, without destroying this fragile material after transferring can be provided.

DESCRIPTION OF SYMBOLS 1 Base film 2 UV curable adhesive layer 3 Fragile material 4 Support body 5 Adhesive layer 6 Transparent substrate 7 UV curable carrier tape 8 of the present invention UV

Claims (2)

An ultraviolet curable carrier tape having an ultraviolet curable pressure-sensitive adhesive layer formed on at least one surface of a substrate film,
The arithmetic average roughness Ra of the adhesive surface of the ultraviolet curable adhesive layer is 10 nm or less, and the ten-point average roughness Rz of the adhesive surface of the ultraviolet curable adhesive layer is 100 nm or less. UV curable carrier tape. The adhesive surface of the UV curable adhesive layer is protected by a separator,
The arithmetic average roughness Ra of the separator surface in contact with the adhesive surface of the ultraviolet curable pressure-sensitive adhesive layer is 10 nm or less, and the ten-point average roughness Rz of the separator surface is 200 nm or less. Item 6. The ultraviolet curable carrier tape according to Item 1.

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