JP5691295B2 - Method for producing antistatic film - Google Patents

Description

  The present invention relates to a method for producing an antistatic film.

  Electrostatic charging due to plastic film friction has caused dust, powder, and lighter materials to adhere, regardless of food or industrial applications. Further, electrostatic charging has been a problem as a cause of destruction of electronic components sensitive to static electricity. Such a problem tends to occur particularly in a low humidity environment, and there is a strong demand for a plastic film that can prevent static electricity troubles in a low humidity environment.

  As a means for preventing this charging, a method of kneading an antistatic agent into the plastic film itself, a method of applying or depositing an antistatic agent on the surface, etc. have been adopted. Exuded to develop its effect, but the exudation affects other properties. In addition, when applied, deterioration occurs due to a reduction in effect due to transfer when the film is wound, or due to an external environment (temperature, humidity, dirt). There is a similar concern in vapor deposition, but the method and materials are limited and the cost is high. In addition, in order to avoid these problems, a method of removing the charge by adding an antistatic agent to the laminating adhesive in the laminate film as in the present invention has also been proposed. As an adhesion primer, the thing like the following patent document 1 is well-known.

  However, the known antistatic adhesive primer has a drawback that its performance is greatly affected by the humidity in the air, and the laminated film using the primer is similarly affected by the humidity in the air. Also, Patent Document 2 below describes a technique using an antistatic adhesive primer, but since it is solventless, development of a solvent-based one that occupies most of the current laminate adhesive is required. .

Japanese Patent No. 2608383

JP 2009-35659 A

  An object of the present invention is to provide a method for producing an antistatic film that maintains excellent antistatic performance even in a low humidity environment.

  Such an object is achieved by the present invention described in the following [1] to [7].

[1] A method for producing an antistatic film comprising a plurality of resin layers bonded together through an adhesive layer, wherein the adhesive layer contains a surfactant (a1) and an alkylene carbonate (a2) agent (a), I adhesive compositions der comprising an adhesive resin (B) and solvent (C), the adhesive resin (B) is a thermosetting adhesive resin containing a polyurethane composition, charge The manufacturing method of a prevention film.

[2] The method for producing an antistatic film according to [1], wherein the surfactant (a1) is an ionic surfactant.

[3] The weight ratio (a1 / a2) between the surfactant (a1) and the alkylene carbonate (a2) in the antistatic agent (A) is a1 / a2 = 90 / 10-60 / 40 [1] Or the manufacturing method of the antistatic film as described in [2].

[ 4 ] Any of [1] to [ 3 ], wherein the weight ratio (A / B) of the antistatic agent (A) to the adhesive resin (B) is A / B = 10/90 to 70/30. A method for producing an antistatic film as described in 1.

[ 5 ] The method for producing an antistatic film according to [2], wherein the ionic surfactant is a cationic surfactant.

[ 6 ] The method for producing an antistatic film according to [ 5 ], wherein the cationic surfactant is an alkyl quaternary ammonium ethosulphate.

  The antistatic film produced by the production method of the present invention suppresses the electrostatic induction phenomenon even in a low humidity environment and has excellent antistatic properties in a low humidity environment.

  More specifically, for example, the antistatic film manufactured by using the manufacturing method of the present invention is a film charged by friction or the like, which suppresses adhesion of dust, powder and other lightweight materials, and charged dust / Electrostatic induction phenomenon from lightweight materials such as powder can be prevented without depending on humidity, so electronic components can be attached by coulomb force caused by charging of electronic components during peeling and electronic components by ESD Can be prevented.

It is a schematic sectional drawing which shows an example of the antistatic laminated | multilayer film manufactured by the manufacturing method of this invention. It is a schematic sectional drawing which shows an example of the cover tape for electronic component packaging manufactured by the manufacturing method of this invention. It is an example of the polarization microscope image which shows the favorable dispersion state of the component at the time of apply | coating an adhesive composition to a to-be-adhered body. It is an example of the polarization microscope image which shows the dispersion | distribution failure state of the component at the time of apply | coating an adhesive composition to a to-be-adhered body.

  Hereinafter, the production method of the antistatic film of the present invention will be described in detail.

(Processing process)
The antistatic film is produced by bonding a plurality of resin films through an adhesive layer.

(Resin film)
The resin film to be bonded to produce the antistatic film is not particularly limited, and is selected depending on the use of the antistatic film. For example, since the film needs strength for use as a cover tape for packaging electronic parts, one or more of PET, PP, nylon and the like subjected to biaxial stretching treatment are used. Furthermore, in order to impart cushioning properties, sealing properties, etc., unstretched resins may be selected. These do not need to be prepared in the state of a film, and are adhesive layers provided according to the production method of the present invention. It may be laminated by extruding or coating from pellets so as to pass through. For example, a laminated film can be produced by using the adhesive composition of the present invention as an anchor coating material at the time of laminating films by an extrusion laminating method, thereby giving a stable antistatic property to the laminated film. it can

(Antistatic agent (A))
The antistatic agent contained in the adhesive composition used in the production method of the present invention contains a surfactant (a1) and an alkylene carbonate (a2).

(Surfactant (a1))
By using the surfactant (a1), the antistatic property of the adhesive composition and the adherend can be improved.
This is because the surfactant (a1) itself can impart antistatic performance to the added material by exhibiting ionic conductivity by utilizing moisture or the like.

  There are various known surfactants, but those which are dissolved in alkylene carbonate (a2) and are transparent are preferred, and examples thereof include a non-aqueous ionic electrolyte solution of a cationic antistatic agent. Among the nonionic electrolytes, alkyl quaternary ammonium etosulphate is preferable from the viewpoint of antistatic properties.

(Alkylene carbonate (a2))
By containing the alkylene carbonate (a2) in the antistatic agent (A), it becomes possible to make the surfactant compatible with the adhesive resin (B) without impairing the antistatic property expressed by the surfactant, and transparent An adhesive composition can be obtained. This is because the alkylene carbonate itself has a high dielectric constant, and it can exhibit ionic conductivity like water that has been generally used by using a surfactant solvent. This is because it plays a role as a compatibilizer between (a1) and the adhesive resin (B).

  In addition, since alkylene carbonate itself does not have adhesive performance and is added as a medium for expressing the effect of the antistatic agent, it is sufficient to add the necessary number of parts for the performance. Specifically, the weight ratio (a1 / a2) of surfactant (a1) / alkylene carbonate (a2) is preferably a1 / a2 = 90 / 10-60 / 40. When the weight ratio of the alkylene carbonate (a2) is less than or equal to the lower limit of the above range, the antistatic agent effect is reduced due to a lack of an antistatic medium. Therefore, when added to the adhesive, the adhesive strength is insufficient.

  More specific examples of alkylene carbonates include those in which propylene carbonate is available.

(Adhesive resin (B))
The adhesive resin (B) used in the present invention is not particularly limited as long as it is an adhesive capable of bonding an adherend such as a film, and therefore there are many types. Specific examples include ester-based and ether-based adhesives, and urethane-isocyanate curing type adhesives that are compatible with the ester-based adhesives are preferable in consideration of maintaining the transparency of the adhesive. In the case of the two-component curing type, there are an ester type and an ether type as the main agent, but an ester type is preferable as described above. Examples of the curing agent include an aromatic type and an aliphatic type, and both can be used, but the aliphatic type is preferable in terms of use without yellowing after curing.

  The weight ratio (A / B) of the antistatic agent (A) to the adhesive resin (B) in the adhesive composition of the present invention is preferably A / B = 10/90 to 70/30. By setting the weight ratio of the antistatic agent (A) to the range lower limit value or more, the adhesive composition has suitable antistatic performance, and by setting the weight ratio to the range upper limit value or less, suitable adhesive performance is obtained. It will be a thing.

(Solvent (C))
The solvent (C) is not particularly limited since a known solvent can be used, but it is preferably selected from those that dissolve the adhesive resin and are compatible with alkylene carbonate. From the viewpoint of reducing the use of environmentally hazardous substances, it is preferable to use ethyl acetate.

  The weight ratio of the solvent (C) in the entire adhesive composition is 60 to 90% by weight. When the weight ratio of the solvent exceeds the lower limit of the above range, the adhesive spreads when the adhesive is coated, and the coating can be applied without causing uneven appearance. On the other hand, when the value is below the upper limit, the production efficiency is improved without taking time for the solvent to volatilize, and the antistatic agent can be dispersed without agglomeration.

(Method for producing adhesive composition)
The adhesive composition may be added to the adhesive resin (B) after dissolving the surfactant (a1) in the alkylene carbonate (a2) to produce the antistatic agent (A). In addition, when using what mixed 2 or more types of adhesive resin as adhesive resin (B), antistatic agent (A) is mixed by previously mixing antistatic agent (A) with any adhesive resin. ) Is improved.

(Laminated film)
As shown in FIG. 1, by using the adhesive composition of the present invention as the adhesive layer 2, two or more adherend resin layers 1 can be bonded to form a laminated film. As a more specific use example, an electronic component packaging cover tape as shown in FIG. As shown in FIG. 2, the electronic component packaging cover tape 20 is preferably composed of at least a plurality of resin layers of a base layer 3, an intermediate layer 4, and a heat sealant layer 5. It is preferable that the layers are laminated via the adhesive composition of the present invention. In particular, from the viewpoint of easy insertion of the adhesive layer, the base material layer 3 and the cushion layer 4 are combined as shown in FIG. It is preferable to laminate by the adhesive layer 6.

(Preparation method of antistatic film)
The method for producing a laminated film using the adhesive composition of the present invention is not particularly limited. For example, when the films are bonded by an extrusion laminating method, the adhesive composition of the present invention is used as an anchor coating material for lamination. A film can be produced, and thereby stable antistatic properties can be imparted to the laminated film.

(Preparation of adhesive composition)
In accordance with the formulation shown in Table 1, the following raw materials were added and dissolved in propylene carbonate, and then a solvent and a polyurethane composition were further added and mixed using a propeller type stirrer. Thereafter, the isocyanate composition was mixed with a propeller-type stirrer before bonding the film to obtain an adhesive composition.
The polyurethane composition and the isocyanate composition are blended so that the polyurethane composition / isocyanate composition is 6/1 by weight, and the total component of the polyurethane composition and the isocyanate composition is the adhesive resin (B). And The adhesive resin B in Tables 1 and 2 described the total amount of the resin components of the polyurethane composition and the isocyanate composition.
Surfactant: NOF Co., Ltd. Cationic surfactant Elegan 264-WAX
Polyurethane composition: Mitsui Chemicals, Inc. Takelac A-520
Isocyanate composition: Takenate A-10 manufactured by Mitsui Chemicals
Solvent: Ethyl acetate

(Preparation of antistatic film)
A biaxially stretched polyester film having a film thickness of 25 μm (PET product number: FE2021 manufactured by Phutamura Chemical Co., Ltd.) is used as the base material layer, and each adhesive composition obtained as described above is used as an adhesive layer (film thickness 1 μm). Charged by forming an intermediate layer (low density polyethylene manufactured by Sumitomo Chemical Co., Ltd .: Sumikasen L705) on the base material layer by extrusion lamination (drying furnace temperature 80 ° C .: line speed 150 m / min) to a film thickness of 25 μm. A prevention film was prepared.

(Evaluation of dispersibility of adhesive composition components)
It applied to the film and observed with the polarization microscope, the presence or absence of component uneven distribution was confirmed, and the thing without uneven distribution was set as the pass.

(Anti-friction property)
After slitting each antistatic film produced as described above to a width of 5.5 mm, an electronic component (size: 2 mm × 2 mm × 1 mm, surface on the cover tape side) on a polystyrene carrier tape (material: carbon kneaded polystyrene) having a width of 8 mm Of 4 mm ² ). Since each laminated film obtained as described above cannot be heat-sealed as it is, both ends are attached with an adhesive tape so as to be in a pseudo taping state to obtain an electronic component package.

  About the sample of the electronic component packaging body obtained above, vibration of 300 reciprocations / minute was given for 1 minute, and the charged voltage on the film after removing the electronic components inside the packaging body was measured. The charged voltage is shown as an absolute value. 50V or less was considered acceptable. In addition, the measurement of the charged voltage was implemented by setting the distance between a sample and a probe to 1 mm using a surface potential meter manufactured by TREK Co., Ltd.

(Surface resistance)
The surface resistance value of each laminated film produced as described above was measured using a surface resistance measuring device manufactured by SIMCO, and the surface resistance after application and drying of the adhesive for dry lamination was measured (measurement condition 23 ° C.-20% RH). 1 × 10 ¹⁰ Ω / □ or less was accepted.

(Electrostatic voltage decay time)
When each of the laminated films prepared as described above was charged to 5 kv, the decay time when the charged voltage of the film was reduced to 1% was measured using an electrostatic decay meter manufactured by ETS Corporation. 10 seconds or less was considered acceptable.

  The evaluation results for each example and comparative example are shown in Tables 1 and 2.

  Examples 1 to 6 were results in which all evaluation items passed. On the other hand, Comparative Example 1 in which the antistatic agent (A) is not added to the adhesive layer and Comparative Examples 2 and 3 in which the surfactant (a1) or the alkylene carbonate (a2) is not added are insufficient in the electrostatic damping effect. And the comparative example 4 which does not contain adhesive resin (B) was in the state where the lamination strength was insufficient.

  According to the manufacturing method of the present invention, an antistatic film that has an effect of suppressing electrostatic induction phenomenon even under low humidity and does not cause uneven distribution of components after film formation can be produced. For example, it is used for a cover tape for packaging electronic components. Suitable for.

DESCRIPTION OF SYMBOLS 1 ... Adhesive resin layer 2 ... Adhesive layer 3 ... Base material layer 4 ... Intermediate layer 5 ... Sealant layer 6 ... Adhesive layer 7 ... Component in adhesive Uneven location 10 ・ ・ Antistatic film 20 ・ ・ Electronic parts packaging cover tape

Claims (6)

A method for producing an antistatic film obtained by bonding a plurality of resin layers through an adhesive layer,
An antistatic agent (A) in which the adhesive layer contains a surfactant (a1) and an alkylene carbonate (a2);
An adhesive composition comprising an adhesive resin (B) and a solvent (C),
The adhesive resin (B) is Ri thermosetting adhesive resin der containing a polyurethane composition,
The alkylene carbonate (a2) is 2.5 parts by mass or more and less than 93.4 parts by mass with respect to 100 parts of the adhesive resin (B).
A method for producing an antistatic film. The method for producing an antistatic film according to claim 1, wherein the surfactant (a1) is an ionic surfactant. Weight ratio of surfactant (a1) to alkylene carbonate (a2) in antistatic agent (A) (a
The method for producing an antistatic film according to claim 1 or 2, wherein 1 / a2) is a1 / a2 = 90/10 to 60/40. The weight ratio (A / B) between the antistatic agent (A) and the adhesive resin (B) in the adhesive layer is A / B.
The method for producing an antistatic film according to any one of claims 1 to 3, wherein = 10/90 to 70/30. The method for producing an antistatic film according to claim 2, wherein the ionic surfactant is a cationic surfactant. The method for producing an antistatic film according to claim 5, wherein the cationic surfactant is an alkyl quaternary ammonium etsulfate.