JPH0718619Y2 - Top tape film - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to chip parts such as fixed resistors, capacitors, inductors, semi-fixed volumes, ICs, LSIs, diodes, etc.
Small outline pack (SO
P) or quad flat pack (QFP), etc.
The present invention relates to a top tape film for carrier tape used for transportation.

[Prior Art] In general, a top tape film for a carrier tape uses a polyester film or a polyester / polyolefin two-layer coextrusion film having a thickness of 10 to 50 μm as a base film, and a styrene-butadiene-styrene block copolymer resin, ethylene-acetic acid. A heat-sealable adhesive layer having a thickness of 10 to 30 μm made of vinyl copolymer resin or the like provided by a film laminating method or a coating method is widely used.

This top tape film is used to heat-seal both ends of the film to the carrier tape by putting the lid on the carrier tape after the parts are stored in the cavity of the carrier tape. It is to be peeled off from the carrier tape when components are mounted by an automatic mounting machine such as a mounter.

[Problems to be solved by the invention] Since this top tape film is unwound and wound several times in the manufacturing process and the use process, it is easily charged with static electricity due to friction and contact.
When the top tape film is peeled from the carrier tape, the storage parts are electrostatically attached to the top tape film side and fall off from the carrier tape. Complementary MOS-IC,
Electrostatically weak semiconductor elements such as transistors, transistor logics, MOS-field effect transistors, bipolar transistors, Schottky diodes, etc., when contacted with this top tape film, are electrostatically destroyed by discharge.

Therefore, this top tape film is generally used by kneading an antistatic agent into the heat-sealable adhesive layer or coating the back surface of the film. It is said that the surface resistance for obtaining the antistatic effect of the top tape film must be 10 ¹¹ Ω or less per unit area to prevent the parts from falling off when peeling the film as described above. 10 ⁹ Ω to prevent electrostatic damage to the element
Hereafter, it is said that the resistance is preferably 10 ⁷ Ω or less.

As an effective means for giving such an antistatic effect, there is a method of adding conductive powder such as carbon black or fine metal powder to the adhesive layer.
Since it is necessary to visually inspect the marking characters of the parts through the film surface, transparency is required, and therefore it cannot be practically adopted.

Therefore, as a method to increase the conductivity of the top tape film surface, an antistatic method using a transparent or translucent surfactant, that is, an anionic activator, a cationic activator, a nonionic activator, an amphoteric activator, etc. Generally, a method of imparting hydrophilicity and ionicity to the surface of the top tape film by kneading the surface active agent into the adhesive layer of the film or coating the back surface of the film is generally performed.

Examples of such antistatic agents include aliphatic quaternary ammonium salt type cationic surfactants, carboxybetaine type amphoteric surfactants, anionic surfactants such as higher alcohol phosphate ester / sodium salt, polyoxyethylene. Examples include nonionic surfactants such as sorbitan fatty acid ester and polyoxyethylene alkylamine.

The above-mentioned antistatic agent is commercially available in the form of powder, aqueous solution or oil solution, and it is used by kneading it into the heat-sealable adhesive layer or coating it on the back surface of the film. However, in general, the surfactant is
OO ^- M ⁺ , -OSO ₃ ^- M ⁺ , -SO ₃ ^- M ⁺ (M above is H, Na, K etc.), {-
_{N (CH 3) 2 -}} + X - (X is Cl, a halogen element such as Br), - OH, - ( C
Since hydrophilic groups such as H ₂ CH ₂ O) _n − are arranged toward the atmosphere and the hygroscopicity thereof lowers the electric resistance, they are easily influenced by the humidity of the atmosphere, and the normal temperature and humidity (5
Surface resistance per unit area is 1 to 35 ℃, 45 to 85% RH)
Since it is ⁰⁹ Ω or more, it is not useful for preventing electrostatic breakdown of the above-mentioned semiconductor element. When it is kneaded into the adhesive layer, the compatibility between the adhesive resin and the antistatic agent becomes a problem, and when the compatibility is poor, it bleeds to the surface of the adhesive layer and deteriorates the heat seal adhesive performance. The coating on the film surface has a problem that it tends to dissolve in moisture and lose its antistatic effect. Therefore, at present, there is no top tape film having a satisfactory antistatic ability.

[Means for Solving the Problems] The present invention relates to a top tape film having excellent antistatic ability capable of solving such disadvantages, and a carrier tape having a heat-sealable adhesive layer on one surface of a base film. In a top tape film for use, the adhesive layer comprises at least two kinds of 7,7,8,8 having different crystal forms.
-Containing a tetracyanoquinodimethane salt (hereinafter abbreviated as TCNQ salt) and having a surface resistance of 10 ⁹ Ω or less per unit area, or at least a crystalline form on the opposite surface of the adhesive layer. We propose a top tape film containing a resin coating layer (hereinafter referred to as a back surface coating layer) containing two or more different TCNQ salts having different surface resistances and having a surface resistance of 10 ⁹ Ω or less per unit area. The surface resistance is Ω /
□ is also displayed.

The TCNQ salt in the present invention is a salt or complex of 7,7,8,8-tetracyanoquinodimethane (hereinafter abbreviated as TCNQ) and a suitable donor (D ⁺ ), (Here, m is 0 ≦ m ≦ 2).

For conductivity, the volume resistivity can be adjusted in a wide range of 10 ⁻⁴ to 10 ⁺⁶ Ω · cm depending on the type of donor (D ⁺ ) to be combined.

For D ⁺ , for example, a cation represented by the following formula can be used. In the following formula, R ₁ , R ₂ , R ₃ and R ₄ represent hydrogen (H) or a monovalent or divalent hydrocarbon group having 1 to 30 carbon atoms.

This TCNQ salt is produced as a crystalline powder and is contained in a solvent solution of a polymer substance in an amount of 3 to 2 with respect to 100 parts by weight of the solid content of the polymer substance.
When 00 parts by weight is dissolved or dispersed and a thin film is formed on the surface of the plastic film using a coating machine such as a gravure coater, roll coater, or spin coater, the TCNQ salt forms fine needle-like crystals or plate-like crystals in the thin film. Precipitated as crystals,
A net-like chain grows and conductivity is obtained. The crystals of this TCNQ salt are very small and can maintain transparency when the film thickness is several μm or less.

This surface resistance varies depending on the type of TCNQ salt used, the types of polymer and solvent, and the blending ratio of TCNQ salt, but it is 10 ⁺⁴ to 10 per unit area in the range of several hundred nm to several μm.
It can be controlled freely within the range of ⁺⁹ Ω.

The TCNQ salt used in the present invention is, for example, isoquinolinium that satisfies the above surface resistance range.
Isoquinolinium salts such as TCNQ complex (0.1Ω · cm) and N-n-butylisoquinolinium TCNQ complex (3Ω · cm),
Morpholinium salts such as N-n-butyl-N-methylmorpholinium TCNQ complex (4Ω · cm), quinolinium TC
NQ complex (0.1Ω ・ cm), Nn-hexylquinolinium T
Quinolinium salts such as CNQ complex (1Ω · cm), Nn-
Examples thereof include pyridinium salts such as propylpyridinium TCNQ complex (20 Ω · cm) and picolinium salts such as Nn-butyl-α-picolinium TCNQ complex (3 Ω · cm). TC over species
It is necessary to use an NQ complex, for example, a needle-like crystal form complex such as N-n-butylisoquinolinium TCNQ complex and N-n-
It is preferable to use a mixture with a plate crystal complex such as butyl-N-methylmorpholinium TCNQ complex. The reason for this is that when the mixing ratio of the TCNQ salt to the binder base material resin is constant, two types of TCNQ complexes having different crystal forms, for example, a needle crystal form complex and a plate crystal form complex are mixed and used, The number of contact points between crystals increases due to overlapping or entering into the gap, and the volume resistivity and surface resistance of the coating film can be made lower than when using the same crystal form complex. In the case of obtaining, it is possible to reduce the cost by reducing the thickness of the coating film, and further, it is possible to improve the transparency, and the conductivity is improved by the same coating thickness. This is because it is possible to mitigate the decrease in the antistatic effect under various environmental conditions.

The mixing ratio of two or more TCNQ complexes having different crystal forms may be any ratio as long as the lowest surface resistance is obtained, and this can be experimentally determined.

According to the experimental results of the present inventors, it was found that the lowest surface resistance was obtained when the ratio of needle-like crystal complex / plate-like crystal complex was 2/1.

As the base material resin for the binder of TCNQ salt, polystyrene (PS), polymethyl methacrylate (PMMA), polyvinyl butyral (PVB), saturated copolyester, polyurethane, nylon 11 and 12, ethylene-vinyl acetate copolymer resin ( EVA), ethylene-ethyl acrylate copolymer resin (EEA), ionomer resin, 1,2-polybutadiene,
Styrene-butadiene-styrene block copolymer resin (S-B-S), styrene-isoprene-styrene block copolymer resin (S-I-S), styrene-ethylene.
Examples include butylene-butylene block copolymer resin (S-EB-S), but when heat sealing the top tape to the carrier tape, the adhesive layer is required to melt instantly and adhere to the carrier tape. If the coating layer is melted by heat from the heat sealer, it will hinder the work and heat resistance is required.Therefore, the base material resin used for the adhesive layer and the base material resin used for the back coating layer Must be considered separately.

That is, as the resin used for the adhesive layer, saturated copolyester, PVB, EVA, S-B-S, S-I-S, S-EB-S, nylon 11 and 12, etc. are suitable, and As the resin used for the coating layer, it is preferable to use thermosetting polyurethane, high glass transition point saturated copolyester, or the like. When the saturated copolyester is used, it is preferable to add a curing agent such as an isocyanate in order to improve heat resistance, and heating aging for accelerating the urethane crosslinking reaction by adding the curing agent (example , 60 ℃ x 72
It is optional to add an antiblocking agent such as a perfluoroalkyl group-containing block copolymer so that the top tape films do not block each other during the time period).

TCNQ salt is applied by dissolving it in the above resin solution.
Since the soluble solvent of the salt is limited, for example, dimethylformamide, dimethylacetamide, propylene carbonate, r-butyrolactone, dimethylsulfoxide, sulfolane, formamide, N-methyl-2-pyrrolidone, acetonitrile, propionitrile, cyclohexanone. , Tetrahydrofuran, isophorone, 1,4-dioxane, dimethoxyethane, methyl ethyl ketone and the like are preferably used. These need to be used alone or as a mixed solvent, but in consideration of volatility during coating film formation, it is preferable to use cyclohexanone, methyl ethyl ketone or the like.

The production of the top tape film of the present invention will be described in more detail.

First, using a blade type stirring and kneading device such as a spiral mixer, a planetary mixer, a disperser, and a hybrid mixer, the above resin is dissolved in the above solvent,
Then, at least two or more kinds of TCNQ salts having different crystal forms may be dissolved or dispersed in 3 to 200 parts by weight with respect to 100 parts by weight of the resin by using the same kneading device. After this, it is desirable to thoroughly dissolve or disperse using a ball-type kneading device such as a ball mill, a vibration mill, or a sand mill. Further, when undissolved or coarse-grained TCNQ salt crystals remain in this TCNQ salt-dissolved solution, its transparency decreases, and the haze value (haze) increases. It is desirable to filter the coating solution.

If this kneading device is made of steel or copper alloy, the TCNQ salt will generate chelates and deteriorate, and the surface resistance after film formation will easily exceed 10 ⁹ Ω per unit area. It is preferable to use plated or stainless steel equipment.

This resin / solvent / TCNQ salt mixed solution (hereinafter abbreviated as TQ coating solution) can be coated on a plastic film using a coating machine such as a gravure coater. The head is also preferably made of chrome plating for the same reason as above.

To coat the TQ coating liquid to the thickness described below,
Viscosity 1000 cP or less, desirably 10-200 cP, solid content 2-3
It is necessary to set within the range of 5% by weight.

Since the TCNQ salt is relatively expensive, it is desirable that the adhesive layer and the back coating layer have a small film thickness, and the back coating layer preferably has a submicron to 1-2 μm range.

Since the thickness of the adhesive layer affects the adhesive strength, 1μ
m or more is required, but the thickness is 5 μm in relation to the adhesive strength.
When the above is required, an adhesive layer containing no TCNQ salt is provided on the first layer, and an adhesive layer containing TCNQ salt is provided on the second layer (thickness submicron to 1 to 2 μm). Good.

The base film used for the top tape of the present invention may be a conventionally used polyester film having a thickness of 10 to 50 μm or a polyester / polyolefin bilayer film, but the bilayer film is more expensive and the front and back surfaces are It is preferable to use the polyester film alone because it is difficult to identify the polyester film.

[Examples] Next, the present invention will be described in more detail with reference to Examples.

Example 1 and Comparative Example 1 A 25 μm thick polyester film (Lumirror T type, manufactured by Toray Industries, Inc.) was used as a base film.

As a heat-sealable adhesive, 100 parts by weight of a saturated copolyester (UE-3221, a product of Unitika Ltd.) having a glass transition point of 2 ° C. and a ring-and-ball method softening point of 115 ° C. is mixed with cyclohexanone / methyl ethyl ketone (80/20) mixed solvent 300 Dissolve 1 part by weight with a disperser, and add 3.3 parts by weight of Nn-butylisoquinolinium TCNQ complex (# 313, prototype of Nitto Kagaku Kogyo Co., Ltd.) and Nn-butyl-N-methyl. 1.7 parts by weight of morpholinium TCNQ complex (prototype name of Nitto Kagaku Kogyo Co., Ltd.) was added, and the mixture was stirred and dispersed by a disperser and then sand milled to prepare a coating solution A having a viscosity of 100 cP.

Next, as a backside coating layer, a saturated copolymerized polyester (XA-7539, having a glass transition point of 90 ° C and a ring and ball softening point of 185 ° C)
10 parts by weight of Unitika Ltd.) was dissolved in 400 parts by weight of a mixed solvent of cyclohexanone / methyl ethyl ketone (80/20) using a disperser, and Nn-butylisoquinolinium TCNQ complex (# 313, 3.3 parts by weight of Nitto Chemical Co., Ltd. (prototype name) and 1.7 parts by weight of Nn-butyl-N-methylmorpholinium TCNQ complex (prototype name of Nitto Chemical Co., Ltd.) were added, and the mixture was stirred and dissolved with a disperser and then sand milled. Then, a coating solution B having a viscosity of 10 cP was prepared.

Using a direct gravure coater having a plate roll of 180 mesh and a depth of 35 μm, one side of the polyester film is coated with the coating solution B and dried to form a backside coating layer having a thickness of 1 μm.
The surface resistance was measured by applying
It was 10 ⁵ Ω.

Next, in place of a plate roll having a wire number of 110 mesh and a depth of 60 μm, the coating solution A is applied to the opposite surface of the polyester film and dried to form a heat-sealable adhesive layer having a thickness of about 4 μm, When the surface resistance was measured under the same conditions as above, it was 1 × 10 ⁵ Ω per unit area. The top tape film that had been subjected to this film-forming treatment had a light transmittance of 90.
% Or more and 20% or less of haze, it has sufficient transparency, and a 1 mm wide heat-sealing head was used to bond it to a polyvinyl chloride carrier tape for 1 second under conditions such that the adhesive temperature was 140 ° C. The peel adhesion strength was 40 gf / mm, which was not a problem in use.

The evaluation of this antistatic ability was performed by corona discharge using a static decay meter to measure the surface potential of the sample surface to 1000.
When it was charged to V and the decay time of this surface potential was measured, its half-life was 5 seconds or less on both sides of the film.
(Example 1) FIG. 1 shows a schematic cross-sectional view of a state in which the top tape film obtained in Example 1 above is applied to a carrier tape.

The adhesive layer 3 formed on the surface of the base film 2 of the top tape film 1 has two edge portions 6 of the carrier tape 5,
The surface of 6'is heat-sealed, and the coating layer 4 is formed on the back surface opposite to the base film.

For comparison, in Example 1 above, the antistatic cationic surfactant (Eleak SEl-52, was used instead of the TCNQ complex).
Yoshimura Yushi Kagaku Co., Ltd. (trade name) was used in the same manner except that 5 parts by weight were mixed, and a thickness of 4 μm was formed on the base film.
The adhesive layer was formed. The surface resistance was 5 × 10 ¹¹ Ω per unit area. As the back coating layer, a quaternary ammonium salt type acrylic polymer antistatic agent (ELIKE PS-501) was directly applied and a dry coating (thickness 1 μm was used.
m), the surface resistance is 2 × 10 ⁹ Ω per unit area
Met. Further, when a surface potential decay test similar to the above was conducted, the half-life was about 50 seconds for the adhesive layer and about 35 seconds for the back surface coating layer. Comparative Example 1 Example 2 A 38 μm-thick polyester film (Lumirror T type, manufactured by Toray Industries, Inc.) was used as a base film.

As the heat-sealable adhesive layer, an insulating coating solution C (viscosity 90 cP) obtained by removing the TCNQ complex from the coating solution A of Example 1 was prepared.

Next, as a back coating layer, 10 parts by weight of the saturated copolyester (XA-7539, trade name manufactured by Unitika Ltd.) described in Example 1 was added to 400 parts by weight of cyclohexanone / methyl ethyl ketone (80/20) mixed solvent with a disperser. It was dissolved by using, and further, 3.3 parts by weight of N-n-butylisoquinolinium TCNQ complex (# 313, Nitto Chemical Co., Ltd. prototype name) and N-n-butyl-N-methylmorpholinium TCNQ complex ( Nitto Chemical Co., Ltd. prototype name) 1.7 parts by weight are added,
After stirring and dissolving with a disperser, a sand mill treatment was performed, and this was filtered with filter paper (Whatman filter paper No. 3). Then, 100 parts by weight of this filtrate was added with toluene diisocyanate-trimethylpropane adduct prepolymer (Coronate L, trade name of Nippon Polyurethane Industry Co., Ltd.).
After adding 25 parts by weight and 0.1 parts by weight of an antiblocking agent (MODIPER F, trade name of NOF CORPORATION), the mixture was stirred again with a disperser to prepare a coating solution D having a viscosity of 15 cP.

Using a gravure coater having a wire number of 180 mesh and a depth of 35 μm, the above coating solution D is applied to one surface of the polyester film and dried to form a coating layer having a thickness of 1 μm, and the film is heated and aged (60 ° C.). × 72
After that, DC100V was applied to measure the surface resistance, and it was 3 × 10 ⁵ Ω per unit area.

Next, on the opposite side of the film, the number of lines 90 mesh, depth 90
The coating solution C was applied and dried using a gravure coater of μm to form a heat-sealable adhesive layer having a thickness of about 5 μm.

The top tape film subjected to the above film forming treatment had a light transmittance of 90% or more and a haze of 20% or less. Further, as a result of heat-sealing the top tape film to a polyvinyl chloride carrier tape under the same conditions as in Example 1, the peel adhesion strength thereof was 50 to 70 gf / mm, and the same conditions as in Example 1 were used. The surface potential decay half-life was 3 seconds or less.

[Advantage of the Invention] According to the present invention, the heat-sealable adhesive layer surface of the top tape film and / or the back surface of the film is a resin layer surface having at least two kinds of TCNQ salts having different crystal forms, and the surface resistance is a unit area. By setting it to 10 ⁹ Ω or less, it is possible to prevent electrostatic charge of the top tape film and prevent electrostatic dropout of parts and electrostatic damage of semiconductor elements when the film is peeled off. Also improves. Further, this TQ coating liquid coating method can use a general-purpose coating machine such as a gravure coater, and has a surface resistance as low as 10 ⁵ to 10 ⁶ Ω per unit area at a submicron level film thickness. Since it is easy to set the level, a top tape film having excellent antistatic ability can be obtained at low cost despite using a relatively expensive TCNQ salt.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a carrier tape using the top tape film of the present invention. Reference numeral 1 in the figure ... Top tape film 2 ... Base film 3 ... Heat-sealable adhesive layer 4 ... Backside coating layer 5 ... Carrier tape 6, 6 '... Edge of carrier tape

Claims (2)

[Scope of utility model registration request] 1. A top tape film for carrier tape having a heat-sealable adhesive layer on one surface of a base film, wherein the adhesive layer comprises at least two kinds of 7,7,8,8-tetracyano having different crystal forms. A top tape film containing a quinodimethane salt and having a surface resistance of 10 ⁹ Ω or less per unit area. 2. A top tape film for a carrier tape having a heat-sealable adhesive layer on one surface of a base film, and at least two or more 7,7,8,8 having different crystal forms on the opposite surface of the adhesive layer. -A top tape film comprising a resin coating layer containing a tetracyanoquinodimethane salt and having a surface resistance of 10 ⁹ Ω or less per unit area.