JP2012167144A - Coating material for etching - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating material for etching which is excellent in adhesiveness to glass and repealability therefrom, and is capable of forming a relatively thick coating film.SOLUTION: The coating material for etching contains an A-B-A type styrene block copolymer, a thermoplastic resin, a tackifier resin and a solvent. In 100 wt.% of the components excluding the solvent in the coating material for etching, the content of the styrene block copolymer is 50 to 90 wt.%; the content of the thermoplastic resin is 1 to 20 wt.%; and the content of the tackifier resin is 2 to 30 wt.%. The thermoplastic resin is a thermoplastic resin using a monomer constituting an A block component of the styrene block copolymer. The solvent contains a first solvent which is a good solvent to the styrene block copolymer, and a poor solvent to the thermoplastic resin.

Description

  The present invention relates to an etching coating material used for forming a coating film for protecting an electronic component from an etchant used in an etching process, for example, when an electronic substrate is manufactured.

  In recent years, miniaturization, weight reduction, and multifunctionalization of electrical devices have been progressing. Particularly in the field of liquid crystal displays, a technique called system on glass (SOG) is used as a technique for forming a drive circuit or a control circuit on a glass substrate on which a liquid crystal panel is formed.

  In the SOG, after an electronic circuit is formed on a glass substrate, an etching process may be performed using an etchant such as hydrogen fluoride as necessary. In this etching process, if the etchant adheres to the electronic circuit, the circuit may be destroyed. For this reason, the surface of the electronic circuit is protected with a resist or a coating material.

  As an example of such a resist, for example, a resist resin composition for glass etching shown in Patent Document 1 below can be mentioned. However, when this resist resin composition is used, it is necessary to peel off the resist film with an alkaline solution or the like after the etching treatment.

  Moreover, as an example of the said coating material, the moisture proof coating material shown by the following patent document 2 is mentioned, for example. This coating material can be peeled off and removed without using a special chemical after the etching process. However, since the adhesion of the coating film to the glass is too high, there is a problem that the electronic circuit may be destroyed when the coating film is peeled off again.

  Further, in order to protect the electronic circuit from the etchant, it is necessary to apply a coating material to some extent thick. Since the moisture-proof coating material described in Patent Document 2 does not have thixotropy, if the coating material is applied thickly, the coating material flows and the necessary thickness cannot be secured, or the part to be etched is covered with the coating material. I may be forgotten. In some cases, an inorganic filler such as fumed silica is blended to impart thixotropy to the coating material. However, when an inorganic filler is blended, there is a possibility that the permeability of the etching solution is increased in some cases.

JP 2010-256788 A Japanese Patent Laid-Open No. 2006-16531

  An object of the present invention is to provide an etching coating material that is excellent in adhesion to glass and removability, and can form a coating film having a relatively large thickness.

  According to a wide aspect of the present invention, a component containing an ABA type styrene block copolymer, a thermoplastic resin, a tackifier resin, and a solvent, excluding the solvent in the etching coating material. In 100% by weight, the content of the styrene block copolymer is 50% by weight or more and 90% by weight or less, the content of the thermoplastic resin is 1% by weight or more and 20% by weight or less, and the adhesive The content of the imparting resin is 2% by weight or more and 30% by weight or less, the thermoplastic resin is a thermoplastic resin using a monomer constituting the A block component of the styrene block copolymer, and the solvent is There is provided an etching coating material comprising a first solvent that is a good solvent for the styrene block copolymer and a poor solvent for the thermoplastic resin.

  In a specific aspect of the etching coating material according to the present invention, the styrene block copolymer is a styrene-ethylene / butylene-styrene copolymer, a styrene-ethylene / propylene-styrene copolymer, or a styrene-ethylene- Contains an ethylene / propylene-styrene copolymer.

  In another specific aspect of the etching coating material according to the present invention, the thermoplastic resin is polystyrene.

  In still another specific aspect of the coating material for etching according to the present invention, the tackifying resin is a terpene resin.

  In still another specific aspect of the etching coating material according to the present invention, the solvent further includes a second solvent that is a good solvent for the thermoplastic resin.

In another specific aspect of the etching coating material according to the present invention, when the viscosity at 25 ° C. and a shear rate of 5 s ⁻¹ is η ₅ and the viscosity at 25 ° C. and a shear rate of 20 s ⁻¹ is η ₂₀ , TI = The TI value (thixotropic index) defined by η ₅ / η ₂₀ is 1.05 or more.

  In still another specific aspect of the etching coating material according to the present invention, when the etching coating material is coated on glass and then dried, the 90 ° peel strength of the dried etching coating material with respect to the glass is 0. It is 5 N / cm or more and 5 N / cm or less.

  The etching coating material according to the present invention preferably further includes at least one additive selected from the group consisting of a modifier, an antifoaming agent, and a colorant, and excludes the solvent in the etching coating material. In 100% by weight of the component, the content of the whole additive is preferably 5% by weight or less.

  The etching coating material according to the present invention contains an ABA type styrene block copolymer, a thermoplastic resin, a tackifier resin, and a solvent, and in 100% by weight of the component excluding the solvent in the coating material, The content of the styrene block copolymer is 50 to 90% by weight, the content of the thermoplastic resin is 1 to 20% by weight, and the content of the tackifying resin is 2 to 30% by weight. The resin is a thermoplastic resin using a monomer constituting the A block component of the styrene block copolymer, the solvent is a good solvent for the styrene block copolymer, and the thermoplastic resin On the other hand, since the first solvent, which is a poor solvent, is included, it is excellent in adhesion to glass and removability, and a coating film having a relatively large thickness can be formed.

FIG. 1 is a front sectional view schematically showing an example of a structure in which a coating film is formed on the surface of an electronic component on a glass substrate using an etching coating material according to an embodiment of the present invention. .

  Hereinafter, the present invention will be described in detail.

  The coating material for etching according to the present invention contains (a) an ABA type styrene block copolymer, (b) a thermoplastic resin, (c) a tackifying resin, and (d) a solvent. To do. (B) The thermoplastic resin is a thermoplastic resin using a monomer constituting the A block component of the (a) styrene block copolymer. The solvent (d) includes a first solvent (a) a good solvent for the styrene block copolymer and (b) a poor solvent for the thermoplastic resin. That is, the first solvent is (a) a good solvent for the styrene block copolymer and (b) a poor solvent for the thermoplastic resin.

  In 100% by weight of the component excluding the solvent (d) in the etching coating material according to the present invention, the content of the (a) ABA type styrene block copolymer is 50% by weight or more and 90% by weight or less. (B) The content of the thermoplastic resin is 1 wt% or more and 20 wt% or less, and (c) the content of the tackifier resin is 2 wt% or more and 30 wt% or less. The component (d) excluding the solvent in the etching coating material includes (a) an ABA type styrene block copolymer, (b) a thermoplastic resin, and (c) a tackifying resin. (D) Solvent is not included.

  Moreover, the coating material for etching according to the present invention may be a dispersion in which the components (a) to (c) are dispersed in the solvent (d), and the components (a) to (c) are the components (d). It may be a solution dissolved in a solvent.

  Since the etching coating material according to the present invention has the above composition, it has excellent adhesion to glass and removability, and can form a coating film having a relatively large thickness. In the etching coating material according to the present invention, the coating material can be applied relatively thick even without using an inorganic filler or even if the content of the inorganic filler is small, and a coating film having a relatively thick thickness can be formed. Can be formed.

  The coating material for etching according to the present invention is used for forming a coating film in order to protect an electronic component from an etching solution in an etching process, for example, when manufacturing an electronic substrate. The etching coating material according to the present invention is a coating material for forming a coating film to be etched. The coating material for etching according to the present invention is preferably a glass etching coating material.

  FIG. 1 schematically shows an example of a structure in which a coating film is formed on the surface of an electronic component on a glass substrate using the etching coating material according to one embodiment of the present invention.

  As shown in FIG. 1, the etching coating material is used, for example, to form a coating film 1 for protecting the surface 3 a of the electronic component 3 disposed on the upper surface 2 a of the glass substrate 2. The outer peripheral edge of the coating film 1 is in contact with the upper surface 2 a of the glass substrate 2.

  Hereinafter, the detail of each component contained in the coating material for etching which concerns on this invention is demonstrated.

((A) ABA type styrene block copolymer)
Specific examples of the (a) ABA type styrene block copolymer include styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), Styrene-vinyl isoprene-styrene block copolymer (SVIS), styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene-ethylene / propylene-styrene block copolymer (SEPS), and styrene-ethylene- And ethylene / propylene-styrene block copolymer (SEEPS). (A) The hydrogenated product of various copolymers is also contained in a styrene block copolymer. (A) As for a styrene block copolymer, only 1 type may be used and 2 or more types may be used together.

  In order to withstand the high oxidizing power of the etching solution, the (a) styrene block copolymer preferably has no unsaturated double bond, and SEBS, SEPS or SEEPS is preferable. That is, (a) a styrene block copolymer contains a styrene-ethylene / butylene-styrene copolymer, a styrene-ethylene / propylene-styrene copolymer, or a styrene-ethylene-ethylene / propylene-styrene copolymer. Is preferred. (A) In 100% by weight of the styrene block copolymer, the content of SEBS, SEPS or SEEPS is preferably 20% by weight or more, more preferably 50% by weight or more and 100% by weight or less. (A) SEBS, SEPS, or SEEPS may be sufficient as the whole quantity of a styrene block copolymer.

  Moreover, the ratio of the structural unit derived from styrene is preferably 30% by weight or more and 100% by weight or less in (a) 100% by weight of all the structural units of the styrene block copolymer. When the proportion of the structural unit derived from styrene is 30% by weight or more, the adhesion between the glass and the coating film is further improved, and the phase between (a) the styrene block copolymer and (b) the thermoplastic resin. The solubility becomes even better. (A) The styrene block copolymer may have only a structural unit derived from styrene.

  The content of (a) the styrene block copolymer is 50% by weight to 90% by weight in 100% by weight of the component excluding the solvent (d) in the coating material for etching according to the present invention. In 100 wt% of the component excluding the solvent (d) in the etching coating material according to the present invention, the content of the (a) styrene block copolymer is preferably 60 wt% or more, preferably 85 wt% or less. . (A) When the content of the styrene block copolymer is not less than the above lower limit, the coating film is hardly brittle. (A) When the content of the styrene block copolymer is not more than the above upper limit, the adhesion between the glass and the coating film is further improved.

((B) Thermoplastic resin)
(B) The thermoplastic resin is a thermoplastic resin using a monomer constituting the A block component of the (a) styrene block copolymer. The (b) thermoplastic resin is preferably a polymer of monomers constituting the A block component of the (a) styrene block copolymer. For example, when (a) the styrene block copolymer is SEBS, SEPS or SEEPS, (b) the thermoplastic resin is a thermoplastic resin using styrene, and the thermoplastic resin is a styrene polymer. It is.

  The (b) thermoplastic resin is preferably highly compatible with the (a) styrene block copolymer. (B) The monomer constituting the thermoplastic resin contains the monomer constituting the A block component of (a) the styrene block copolymer, so that (b) the thermoplastic resin, (a) the styrene block copolymer, The compatibility of can be improved. When the compatibility between the (b) thermoplastic resin and the (a) styrene block copolymer is low, these components may phase separate during storage of the coating material. As a result, uneven coating of the coating material is likely to occur.

  (B) Examples of the thermoplastic resin include polystyrene, styrene-acrylonitrile copolymer, styrene-methyl methacrylate (MMA) copolymer, styrene-MMA-acrylonitrile copolymer, and styrene-maleic anhydride copolymer. Can be mentioned. (B) As for a thermoplastic resin, only 1 type may be used and 2 or more types may be used together.

  (B) The thermoplastic resin is preferably a thermoplastic resin using styrene, more preferably polystyrene, a styrene-acrylonitrile copolymer or a styrene-MMA copolymer, and even more preferably polystyrene or a styrene-acrylonitrile copolymer. A polymer, particularly preferably polystyrene. (B) The thermoplastic resin is particularly preferably polystyrene. Polystyrene does not deteriorate with an etching solution having a high acidity, and the adhesion between the glass and the coating film can be easily controlled.

  In 100 wt% of the component excluding the solvent (d) in the etching coating material according to the present invention, the content of the (b) thermoplastic resin is 1 wt% or more and 20 wt% or less. The content of the thermoplastic resin (b) is preferably 3% by weight or more in 100% by weight of the component excluding the solvent (d) in the coating material for etching according to the present invention. When the content of the (b) thermoplastic resin is not more than the above upper limit, it is easy to uniformly disperse the (b) thermoplastic resin in the coating material, and uneven coating hardly occurs.

((C) Tackifying resin)
In order to improve the adhesion between the glass and the coating film, (c) a tackifying resin is used. (C) Examples of the tackifier resin include terpene resins, rosin ester resins, and petroleum resins. Among these, terpene-based resins are preferred because (a) the adhesiveness between the glass and the coating film is effectively increased by using it together with the styrene block copolymer. Examples of the terpene resins include hydrogenated terpene resins, polyterpenes, and terpene phenol resins. (C) As for tackifying resin, only 1 type may be used and 2 or more types may be used together.

  In 100 wt% of the component excluding the solvent (d) in the etching coating material according to the present invention, the content of the (c) tackifying resin is 2 wt% or more and 30 wt% or less. In 100 wt% of the component excluding the solvent (d) in the etching coating material according to the present invention, the content of the (c) tackifying resin is preferably 5 wt% or more, and preferably 25 wt% or less. (C) When the content of the tackifying resin is not less than the above lower limit, the adhesion between a substrate such as glass or a printed circuit board and the coating film is further improved. (C) When content of tackifying resin is below the said upper limit, a coating film becomes difficult to become weak and the adhesiveness of glass and a coating film becomes still better.

((D) solvent)
The coating material for etching according to the present invention contains (d) a solvent in order to disperse or dissolve (a) a styrene block copolymer, (b) a thermoplastic resin, and (c) a tackifier resin.

  Examples of the solvent (d) include aliphatic solvents, ketone solvents, aromatic solvents, ester solvents, ether solvents, alcohol solvents, paraffin solvents, petroleum solvents, and the like.

  Examples of the aliphatic solvent include cyclohexane, methylcyclohexane, and ethylcyclohexane. Examples of the ketone solvent include acetone and methyl ethyl ketone. Examples of the aromatic solvent include toluene and xylene. Examples of the ester solvent include ethyl acetate, butyl acetate and isopropyl acetate. Examples of the ether solvent include tetrahydrofuran (THF) and dioxane. Examples of the alcohol solvent include ethanol and butanol. Examples of the paraffinic solvent include paraffin oil and naphthenic oil. Examples of the petroleum solvent include mineral terpenes and naphtha. (D) As for a solvent, only 1 type may be used and 2 or more types may be used together.

  In the etching coating material according to the present invention, the first solvent (d) is a good solvent for (a) a styrene block copolymer, and (b) a poor solvent for a thermoplastic resin. At least. Here, the good solvent refers to a solvent that becomes transparent and uniform when a 10% by weight solution of a resin component (for example, (a) a styrene block copolymer) is produced at room temperature (23 ° C.). The poor solvent refers to a solvent that does not become transparent or uniform when a 10% by weight solution of a resin component (for example, (b) thermoplastic resin) is produced at room temperature (23 ° C.).

  When (a) the styrene block copolymer is SEBS and (b) the thermoplastic resin is polystyrene, an aliphatic solvent such as cyclohexane or methylcyclohexane is a good solvent for SEBS. On the other hand, although it swells at room temperature, it is difficult to dissolve completely and is a poor solvent. The first solvent is preferably an aliphatic solvent, and is preferably cyclohexane or methylcyclohexane.

  By using the specific first solvent, (b) the thermoplastic resin swells in the coating material, and is dispersed in a fine gel form of several μm to several tens μm, so that the viscosity is high at a low shear rate. Thus, thixotropy is expressed.

  Furthermore, it is preferable that (d) solvent contains the 2nd solvent which is a good solvent with respect to a thermoplastic resin. (B) When the thermoplastic resin is polystyrene, examples of the second solvent that is a good solvent for polystyrene include ketone solvents, aromatic solvents, ester solvents, and ether solvents. By blending these good solvents, the dispersion diameter of the thermoplastic resin gel (b) tends to be small, and the viscosity tends to decrease. As described above, (d) the combination of the solvents can control the dispersion state of (b) the thermoplastic resin, and can control the viscosity and TI value of the coating material.

  Aromatic solvents and ether solvents are good solvents for both (a) styrene block copolymer and polystyrene. When these solvents are used alone, a uniform solution is likely to be obtained. Sex is difficult to express.

  (D) The amount and combination of the solvents are determined according to the coating method. In a general dispensing operation, the solid content concentration is preferably 20% by weight or more, more preferably 25% by weight or more, preferably 50% by weight or less, more preferably 40% by weight or less. The blending amount is adjusted.

  The etching coating material according to the present invention preferably includes the first solvent and the second solvent in a weight ratio of 100: 0 to 50:50, and 90:10 to 70:30. Is more preferable. Only the first solvent may be used, and the second solvent may not be used.

(Other ingredients)
The coating material for etching according to the present invention may contain a modifying agent, an antifoaming agent, a colorant, an adhesiveness imparting agent, and the like as necessary. For example, in order to improve the drying property, an organic acid metal salt such as manganese naphthenate or manganese octenoate can be used as the modifier. In order to improve the adhesion between the substrate and the coating film, one or more methacryloxy, acryloxy, mercapto and amino silane coupling agents can be used as the modifier. . Examples of the antifoaming agent include known antifoaming agents such as silicone oil, fluorine oil, and polycarboxylic acid polymer. Examples of the colorant include known inorganic pigments, organic pigments, and organic dyes. As for a modifier, an antifoamer, a coloring agent, and an adhesive imparting agent, only 1 type may respectively be used and 2 or more types may be used together.

  It is preferable that the etching coating material according to the present invention further includes at least one additive selected from the group consisting of a modifier, an antifoaming agent, and a colorant. In 100% by weight of the component excluding the solvent (d) in the coating material for etching, the total content of the additive is preferably 5% by weight or less. In 100% by weight of the component excluding the solvent (d) in the coating material for etching, the total content of the additive is preferably 0.01% by weight or more, more preferably 0.1% by weight or more. In addition, the said additive is contained in the component except the (d) solvent in the coating material for an etching.

(Etching coating material)
Etching the coating material according to the present invention, the viscosity at 25 ° C. and a shear rate of ^{5s -1} and eta _5, the viscosity at 25 ° C. and a shear rate of ^{20s -1} when the eta _20, with TI = η ₅ / η ₂₀ The defined TI value (thixotropic index) is preferably 1.05 or more.

  The coating film is required to protect the electronic circuit disposed on the glass substrate without excess or deficiency. Accordingly, it is necessary to apply the coating material to a place to be coated, such as an electronic circuit, to a certain extent. On the other hand, in general, when a coating material that is a liquid is applied as it is, it spreads wet, and as a result, the coating material reaches an unnecessary part, or the protective performance against the etching solution decreases because the coating material becomes thin. . In order to prevent this, the viscosity of the coating material may be increased. However, if the viscosity is high, the coating operation is difficult. For this reason, it is desirable that the viscosity be low when the strain rate is large as in the coating operation, and the viscosity be high when the strain rate is small so as to maintain the shape after coating. Such a phenomenon is called thixotropy, and the above TI value is used as this index.

  Therefore, the TI value is preferably 1.05 or more, more preferably 1.1 or more, preferably 1.5 or less, more preferably 1.3 or less. When the TI value is not less than the above lower limit, necessary thixotropy can be obtained, the coating material can be applied relatively thickly, and it becomes easy to form a coating film having a relatively thick thickness. When the TI value is less than or equal to the above upper limit, the viscosity is not excessively increased and the coating material is easily applied.

  Examples of the method for applying the etching coating material according to the present invention on the surface of an electronic circuit include a generally known dipping method, brush coating method, spray method, wire drawing method, and dispensing method. It is preferable to dry after applying the coating material. In order to efficiently apply a thick coating material, a dispensing method is preferable. The etching coating material according to the present invention is preferably an etching coating material applied by a dispensing method.

The optimum viscosity of the coating material varies depending on the application method. In the dispensing method, the viscosity η _{5 at} 25 ° C. and a shear rate of 5 s ⁻¹ is preferably 0.4 Pa · s or more, and preferably 15 Pa · s or less, and the viscosity at 25 ° C. and a shear rate of 20 s ⁻¹ is η ₂₀ Is preferably 0.4 Pa · s or more, and preferably 10 Pa · s or less. It is easy to prevent the coating material from spreading wet when the viscosity is equal to or higher than the lower limit. When the viscosity is less than or equal to the upper limit, the work of separating the coating material into the dispenser is facilitated.

  The viscosity can be measured using a general-purpose viscometer. Examples of the viscometer include an E-type viscometer (“TV-22” manufactured by Toki Sangyo Co., Ltd.).

  When the etching coating material according to the present invention is coated on glass and then dried, the 90-degree peel strength of the etching coating material after drying with respect to the glass is preferably 0.5 N / cm or more, more preferably 0.8. It is 8 N / cm or more, preferably 5 N / cm or less, more preferably 3 N / cm or less. The coating material for etching after drying is a coating film, and the coating film is etched. The coating film is removed by peeling after the glass substrate is etched. When the 90-degree peel strength is equal to or more than the above lower limit, the adhesion between the glass and the coating film is improved, and the coating material can be prevented from spontaneously peeling during the etching process. When the 90-degree peel strength is less than or equal to the above upper limit, the re-peelability of the coating film is improved, and the electronic circuit can be prevented from being destroyed when the coating film is peeled and removed.

  Examples of the electronic component protected using the etching coating material according to the present invention include all electronic circuits on a glass substrate formed of system-on-glass (SOG). The electronic component may include a lead wire, a harness, a film substrate, and the like that are bonded to the electronic component.

  The coating material for etching according to the present invention can be produced by mixing the raw materials and then stirring with a shaker or a disper.

  In the etching coating material according to the present invention, (b) a poor solvent for the thermoplastic resin is used, and (b) the thermoplastic resin needs to be dispersed in a fine gel in the coating material. However, it is difficult to uniformly disperse the thermoplastic resin (b) simply by mixing the raw materials as they are. For this reason, (b) a good solvent of the thermoplastic resin is added in a small amount within a range where the TI value does not become less than 1.05, or it is heated at the time of stirring. The dispersion efficiency of each component in the coating material can be increased by using a compound obtained by melt-kneading the above.

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

  In order to form the etching coating material, the following materials were used.

(A) Styrene block copolymer:
Kuraray "Septon 8104", SEBS, 60% by weight of styrene structural units
Kuraray "Septon 4033", SEEPS, 30% by weight of styrene structural units

  (B) Thermoplastic resin: “G100C” manufactured by Toyo Styrene Co., polystyrene

  (C) Tackifying resin: "Mighty Ace G150" manufactured by Yasuhara Chemical Co., terpene phenol resin (terpene resin)

  Colorant: “OIL BLUE 2N” manufactured by Orient Chemical Industries

(D) Solvent Methylcyclohexane Toluene

(Examples 1-6 and Comparative Examples 1-5)
The components shown in Table 1 below were blended in the blending amounts shown in Table 1 to prepare a coating material (coating material solution).

(Evaluation)
The characteristics of the obtained coating material and the coating film using the coating material were measured by the following method.

(1) Viscosity of coating material Using an E-type viscometer (“TV-22” manufactured by Toki Sangyo Co., Ltd.), the viscosity of the coating material at 25 ° C. was measured.

Viscosity eta ₅ at a shear rate of ^{5s -1,} and measuring the viscosity eta ₂₀ at a shear rate of ^{20s -1,} TI value TI value defined (thixotropic index) at TI = η ₅ / η ₂₀ (thixotropic index )

(2) Peel strength against glass A coating material was applied on a soda-lime glass plate and dried at 50 ° C. for 10 minutes and then at 100 ° C. for 20 minutes. It adjusted suitably so that the thickness of the coating material (coating film) after drying might be set to 200 micrometers. The dried coating material was cut at a width of 10 mm, and peeled off at a pulling rate of 300 mm / min at an angle of 90 ° with respect to the glass plate using a tensile tester. The peel strength at the time of peeling was measured to determine the peel strength against glass.

  The results are shown in Table 1 below. Table 1 below also shows the results of evaluating the appearance of the coating film formed by the evaluation of the peel strength against glass.

  As can be seen from the results shown in Table 1, in the coating materials of Examples 1 and 2 in which 73% by weight of styrene block copolymer, 7% by weight of polystyrene, and 20% by weight of tackifier resin (terpene phenol resin) were blended. Since the peel strength against glass was in an appropriate range, the re-peelability was excellent, and the TI value was large, so that thick coating was possible. Even though the composition of the coating material excluding the solvent was the same, the coating material of Example 3 having a high content of toluene, which is a good solvent for polystyrene, had a low viscosity and a slightly decreased TI value. Further, in the coating material of Example 4 in which the ratio of the styrene structural unit in the styrene block copolymer was large, the coating material was very soft, and thus the peel strength against glass was slightly increased.

  Moreover, in the coating material of the comparative example 1 which did not mix | blend polystyrene, TI value was small. In the coating material of Comparative Example 2 having a high polystyrene content, it was difficult to uniformly dissolve polystyrene, and thus the thickness of the coating material after drying became non-uniform and uneven. Moreover, in the coating material of Comparative Example 3 using only toluene, which is a good solvent for polystyrene, the TI value was small. In the coating material of Comparative Example 4 having a small content of the tackifying resin, the peel strength against glass was considerably low. In the coating material of Comparative Example 5 having a large content of the tackifying resin, the peel strength against glass was considerably high.

DESCRIPTION OF SYMBOLS 1 ... Coating material 2 ... Glass substrate 2a ... Upper surface 3 ... Electronic component 3a ... Surface

Claims (8)

An ABA type styrene block copolymer, a thermoplastic resin, a tackifier resin, and a solvent;
In 100% by weight of the component excluding the solvent in the coating material for etching, the content of the styrene block copolymer is 50% by weight or more and 90% by weight or less, and the content of the thermoplastic resin is 1% by weight or more. 20% by weight or less, and the content of the tackifying resin is 2% by weight or more and 30% by weight or less,
The thermoplastic resin is a thermoplastic resin using a monomer constituting the A block component of the styrene block copolymer,
An etching coating material, wherein the solvent includes a first solvent that is a good solvent for the styrene block copolymer and a poor solvent for the thermoplastic resin.   The styrene block copolymer comprises a styrene-ethylene / butylene-styrene copolymer, a styrene-ethylene / propylene-styrene copolymer, or a styrene-ethylene-ethylene / propylene-styrene copolymer. The coating material for etching as described.   The coating material for etching according to claim 1 or 2, wherein the thermoplastic resin is polystyrene.   The etching coating material according to claim 1, wherein the tackifying resin is a terpene resin.   The coating material for etching according to any one of claims 1 to 4, wherein the solvent further comprises a second solvent that is a good solvent for the thermoplastic resin. TI value defined by TI = η ₅ / η ₂₀ (thixotropic index) where η ₅ is a viscosity at 25 ° C. and a shear rate of 5 s ^−1, and η ₂₀ is a viscosity at 25 ° C. and a shear rate of 20 s ⁻¹ . The coating material for etching according to any one of claims 1 to 5, wherein is 1.05 or more.   When the etching coating material is coated on glass and then dried, the 90 ° peel strength of the etching coating material after drying with respect to the glass is 0.5 N / cm or more and 5 N / cm or less. The coating material for etching according to any one of 6. Further comprising at least one additive selected from the group consisting of a modifier, an antifoaming agent and a colorant;
The coating material for etching according to any one of claims 1 to 7, wherein the content of the whole additive is 5% by weight or less in 100% by weight of the component excluding the solvent in the coating material for etching.

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