KR20040038653A - Mold release sheet for thermo compression bonding and method for manufacturing the same - Google Patents

Abstract

PURPOSE: A mold release sheet for thermo compression bonding and a method for manufacturing the same are provided to have a high anti-static effect, durability and an excellent moldability. CONSTITUTION: The mold release sheet for thermo compression(1) bonding comprises a glass fiber reinforced conductive fluoro carbon resin sheet(2); a surface activation treated plane(3) on at least one side of the conductive fluoro carbon resin sheet(2); and a vulcanized heat conductive and electrical conductive silicone rubber(4) which is laminated and integrated to the activation treated plane(3) of the fluoro carbon resin sheet. The reinforced fibers of the conductive fluoro carbon resin sheet are a fiber glass fabric.

Description

Release sheet for thermocompression bonding and its manufacturing method {Mold release sheet for thermo compression bonding and method for manufacturing the same}

The present invention relates to a release sheet for thermal compression. More specifically, the present invention relates to a heat release release sheet having thermal conductivity and electrical conductivity and capable of preventing static electricity.

The thermocompression-releasing sheet is formed between an external connection electrode of a liquid crystal panel and a heat-compression tool of a thermocompression bonding apparatus and an FPC when thermally compressing an outer lead of a flexible base (FPC) on which a driving semiconductor is mounted through an anisotropic conductive sheet-like adhesive. The FPC can be thermally compressed without being in close contact with the tip of the thermal crimping tool of the thermal crimping device or the object to be pressurized while increasing the parallelism of the thermal crimping surface.

Conventionally, as a release sheet for thermocompression bonding of this kind, silicone rubber-based sheets as described in Japanese Patent Application Laid-Open No. 5-198344, Japanese Patent Application Laid-open No. Hei 7-117175, and Japanese Patent Application Laid-open No. Hei 10-219199; Many conductive silicone composites (Applicant's trade name "Sacon") are used in industry.

However, according to the recent increase in size and size of the connection electrode of the external connection electrode of the liquid crystal panel and the outer lead of the flexible base (FPC) on which the driving semiconductor is mounted, the conventional silicone rubber and thermocompression release sheet is as follows. A problem arises.

(1) In order to secure cracking property at the thermally compressed surface due to the recent increase in size of the liquid crystal panel, a long time thermal pressing time is required, and thus productivity is reduced.

(2) At the same time, since the heater temperature of the heating tool of the thermocompression bonding apparatus is set high, the durability of the thermocompression release sheet decreases.

(3) Many problems arise that the liquid crystal panel and the driving semiconductor are damaged by static electricity generated when the external connection electrode of the liquid crystal panel and the flexible base (FPC) on which the driving semiconductor is mounted are thermally compressed.

An object of the present invention is to provide a thermocompression-releasing sheet having high antistatic effect, excellent releasability, and high durability in order to solve the above-mentioned conventional problems.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing of the release sheet for thermocompression bonding in one Embodiment of this invention.

<Explanation of symbols for the main parts of the drawings>

1: release sheet for thermocompression bonding

2: glass fiber reinforced conductive fluororesin sheet

3: surface activation treatment surface

4: vulcanized thermally conductive electrical conductive silicone rubber

In order to achieve the above object, the thermocompression release sheet of the present invention is a thermocompression release sheet bonded to at least one side of a sheet containing at least one resin selected from a thermoplastic resin and a thermosetting resin. Surface activation treatment is performed on at least one surface of the sheet, and a vulcanized thermally conductive and electrically conductive silicone rubber is laminated integrally on the surface activation treatment surface of the fluororesin sheet.

Moreover, in the manufacturing method of the release sheet for thermocompression bonding of this invention, surface activation treatment is given to at least one surface of a glass fiber reinforced electroconductive fluororesin sheet, and it laminates and integrates a vulcanized electroconductive silicone rubber on the active surface of the said fluororesin sheet A method for producing a release sheet for thermocompression bonding, comprising impregnating a conductive fluororesin mixture into a glass fiber fabric, coating a liquid thermally conductive electroconductive silicone rubber on at least one surface of a sheet which is calcined and integrally composited, and heat-cured It is characterized by integrally stacking.

(Preferred Embodiment of the Invention)

The present invention, after impregnating a glass fiber fabric with a fluorine resin containing a conductive material, and then in order to firmly adhere the thermally conductive electrical conductive silicone rubber to the surface, after the surface activation treatment on at least one surface, the surface activation treatment It is a release sheet for thermocompression bonding which formed the sheet | seat which coat | covered electroconductive silicone rubber on the surface, heat-hardened, and laminated | stacked and integrated. In the above, the volume resistivity (ASTM D-991) after curing of the thermally conductive and electrically conductive silicone rubber is preferably in the range of 10 to 10 ⁵ Pa · cm, and the surface resistivity of the glass fiber reinforced conductive fluororesin sheet is 10 kPa to The range of 500 Hz is preferable.

It is preferable that the reinforcing fiber of the said conductive fluororesin sheet is a glass fiber fabric. This is because glass fiber fabrics have high heat resistance and dimensional stability.

The fluororesin may be tetrafluoroethylene polymer (PTFE), tetrafluoroethylene-6 fluorinated propylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (PETFE), and tetrafluoroethylene-perfluoroalkyl vinyl It is preferable that it is at least 1 resin chosen from an ether copolymer (PFA). This is because these fluorine resins have high chemical stability.

It is preferable that carbon black is mixed 1.0-15 weight part with respect to 100 weight part of fluororesins of the said conductive fluororesin sheet. It is because antistatic property is high in it being the said range.

It is preferable that the said surface activation process is at least 1 sort (s) of treatment chosen from sodium etching surface treatment, discharge surface treatment, plasma surface treatment, and ozone surface treatment. These treatments can improve the adhesion between the inert fluorine resin and the thermally conductive and electrically conductive silicone rubber.

It is preferable that the said silicone rubber is a liquid addition addition vulcanization silicone rubber liquid at 25 degreeC. It is because a thin film sheet is easy to form.

It is preferable that 1.0-200 weight part of metal oxides and 1.0-50 weight part of carbon black are mixed with the said thermally conductive electrical conductive silicone rubber with respect to 100 weight part of silicone rubber. It is because thermal conductivity and antistatic property are high in it being the said range.

As a method of this invention, it is preferable that the heat-hardening (vulcanization) conditions of the said liquid thermally conductive electrical conductive silicone rubber layer are temperature 80-120 degreeC, and processing time 2-20 minutes. If it is this range, sufficient hardening can be performed. More preferred vulcanization time is 5 to 15 minutes, particularly preferably about 8 minutes.

Next, the drawings will be described. 1: is sectional drawing of the release sheet 1 for thermocompression bonding in one Embodiment of this invention. At least one surface of the glass fiber reinforced conductive fluororesin sheet 2 has a surface activation treatment surface 3, and on the active surface 3 of the fluorine resin sheet, vulcanized thermally conductive and electrically conductive silicone rubber 4 is present. Lamination is integrated.

(Example)

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

(Example 1)

(1) glass fiber fabric reinforced conductive fluororesin sheet

As a base material, the plain fabric non-alkali glass fiber fabric (weight per unit area: 36 g / m <2>) was used for the glass fiber fabric reinforced electroconductive fluororesin sheet which is a component of a thermocompression-release release sheet. The compound which added 1.0 weight part of carbon black powders for imparting electrical conductivity with respect to 100 weight part of polytetrafluoroethylene was apply | coated to the said glass fiber fabric, and it impregnated, and baked at 400 degreeC for 30 minutes. Electrical surface resistance of the obtained glass fiber fabric reinforced conductive fluororesin sheet: 5x10 ⁵ Pa, thickness: 0.05 mm, tensile strength: 40 N / cm, elongation: 5% or less, polytetrafluoroethylene content: 65 wt%. The glass fiber fabric reinforced conductive fluororesin sheet may use "Honda Propaburikku" (trade name of Honda Industries, Inc.).

(2) Surface activation treatment of glass fiber fabric reinforced conductive fluororesin sheet

Aqueous sodium hydroxide solution (NaOH concentration: 25 weight%) was provided to one surface of the glass fiber fabric reinforced electroconductive fluororesin sheet obtained by said (1), and it surface-treated. Thereafter, the aqueous sodium hydroxide solution adhered to the surface by washing with water was removed to obtain a uniform and activated surface. This is a step of obtaining a substrate for firmly integrating a thermally conductive and electrically conductive silicone rubber on the surface of a glass fiber fabric reinforced conductive fluororesin sheet.

(3) Thermally Conductive, Electrically Conductive Silicone Rubber

The main component of the liquid conductive silicone rubber, which is already one component, is an organic polysiloxane having at least two or more alkenyl groups in one molecule, and is a known organic polysiloxane which is usually used as a liquid addition reaction type silicone rubber. The viscosity of is at least 5,000 CP, preferably 5,000 CP to 100,000 CP.

As a crosslinking agent, organic hydrogen polysiloxane reacts with a main component, and if it contains the hydrogen atom which couple | bonded with at least 2 or more silicon atoms directly in 1 molecule, there is no restriction | limiting in the molecular structure, The commercially available thing can be used. As a commercially available product, there is a brand name "SH1107" by the company Toray Dow Corning, for example. Acetylene alcohol was used as a reaction inhibitor for adjusting the curing time of the addition reaction. 0.2 weight% of acetylene alcohol was added.

In order to impart conductivity, 100 parts by weight of aluminum oxide (manufactured by Showa Denko, trade name "AS30") as 100 parts by weight of the composition and 100 parts by weight of carbon black (Denki Chemical) 25 parts by weight was added to 100 parts by weight of silicone rubber. As carbon black, although it can normally classify as furnace black, acetylene black, etc., since sulfur and hardening | curing amine content are large, hardening failure of an addition reaction arises, It is especially preferable to use acetylene black.

These were combined suitably and the liquid phase thermally conductive electrical conductive silicone rubber was obtained.

(4) stacking integration

Next, the liquid conductive silicone rubber was coated on one surface of the glass fiber fabric reinforced conductive fluororesin sheet with a continuous coating apparatus, and then heat-cured at 80 ° C. for 10 minutes to obtain a release sheet for thermocompression bonding. The thickness after hardening of the liquid conductive silicone rubber was 0.15 mm, and the weight per unit area thereof was 172 g / m 2. Moreover, the thickness of the laminated monolayer was 0.2 mm, and the weight per unit area was 208 g / m <2>. Moreover, thermal conductivity was 0.8 W / m * k when it measured with Kyoto brand electronics, brand name "QTM-D3" based on JIS-R2616.

(Comparative Example)

As a conventional thermally conductive silicone composite, the trade name "Sacon TR" manufactured by Fujigo Molecular Industries, Ltd. was used as a release sheet for thermocompression bonding. "Sacon TR" is an electrically insulating, thermally conductive silicone rubber sheet heat-vulcanized by adding 70 wt% of aluminum oxide powder to dimethylpolysiloxane and mixed with an organic peroxide, having a sheet thickness of 0.20 mm, volume resistivity of 10 ¹⁵ Pa.cm, It is a sheet of JIS hardness 75 (JIS K 6249).

(exam)

Durability was measured using the above Example product and the comparative example product. The number of short cycles until a crack and tear generate | occur | produced on the conditions (compression tool temperature: 350 degreeC, crimping tool pressure: 3 Mpa, pressurization time: 20 second) of the thermocompressor in actual liquid crystal device assembly was investigated. As a result, the product of the comparative example was 50 to 70 cycles while the product of the comparative example was 10 to 15 cycles.

When compared under the same thermocompression conditions as in the above test results, it can be seen that the Example product of the present invention has a durability of 4.7 to 5 times, which leads to significant process improvement and reduction of material cost.

Next, the electrostatic charging voltage was measured. Charge amount when the crimping tool falls from the release sheet after the thermal crimping under the conditions (compression tool temperature: 350 ° C., crimping tool pressure: 3 MPa, pressurization time: 20 seconds) of the thermocompressor in actual liquid crystal device assembly. Silver comparative example product was 350V-500V, whereas this invention product was 25V-50V.

When compared under the same thermocompression conditions as the test results, the present invention has a static charge voltage of 25V to 50V, heat the external connection electrode of the liquid crystal panel and the flexible base (FPC) mounted with the driving semiconductor The problem that the liquid crystal panel and the driving semiconductor were damaged by the static electricity generated at the time of pressing was solved.

Since the thermocompression release sheet of this invention has high electrical conductivity and an antistatic effect, and high mold release property and thermal conductivity, high short cycling can be performed in a thermocompression bonding machine. It also has high durability. As a result, thermocompression bonding of the highly connected connection electrode part of the external connection electrode of the liquid crystal panel which has a large thermocompression bonding surface, and the outer lead of the flexible base (FPC) in which the drive semiconductor was mounted can be performed efficiently for a short time. Moreover, the yield at the time of thermocompression bonding improves remarkably, and contributes greatly to the productivity improvement of a liquid crystal display panel. Moreover, the thermocompression release sheet of this invention can be used for the thermocompression bonding of the sheet | seat containing a thermoplastic resin or the sheet | seat containing a thermosetting resin, without being limited to the thermocompression bonding of a liquid crystal module panel.

Claims (15)

A release sheet for thermocompression bonding joined to at least one side of a sheet containing at least one resin selected from a thermoplastic resin and a thermosetting resin, Surface activation treatment is performed on at least one surface of the glass fiber reinforced conductive fluororesin sheet, and a thermally vulcanized thermally conductive electrical conductive silicone rubber is integrally laminated on the surface activation treatment surface of the fluororesin sheet. Release sheet for The release sheet for thermocompression bonding according to claim 1, wherein the reinforcing fibers of the conductive fluororesin sheet are glass fiber fabrics. The method of claim 1, wherein the fluorine resin is tetrafluoroethylene polymer (PTFE), tetrafluoroethylene-6 fluorinated propylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (PETFE), and tetrafluoroethylene It is at least 1 resin chosen from a perfluoroalkyl vinyl ether copolymer (PFA), The release sheet for thermocompression bonding characterized by the above-mentioned. The release sheet for thermocompression bonding according to claim 1, wherein the conductive fluororesin sheet contains 1.0 to 15 parts by weight of carbon black based on 100 parts by weight of the fluorine resin. The release sheet for thermocompression bonding according to claim 1, wherein the surface activation treatment is at least one kind selected from among sodium etching surface treatment, discharge surface treatment, plasma surface treatment, and ozone surface treatment. The release sheet for thermocompression bonding according to claim 1, wherein the silicone rubber is a liquid addition reaction vulcanized silicone rubber liquid at 25 ° C. The thermally conductive electrically conductive silicone rubber according to claim 1, wherein 1.0 to 200 parts by weight of the metal oxide powder and 1.0 to 50 parts by weight of carbon black are mixed with respect to 100 parts by weight of the silicone rubber. Release sheet. As a manufacturing method of the release sheet for thermocompression bonding on which at least one surface of a glass fiber reinforced electroconductive fluororesin sheet is surface-activated, and laminating and integrating the vulcanized conductive silicone rubber on the active surface of the said fluororesin sheet, Immersion of the conductive fluororesin mixture in a glass fiber fabric, coating a liquid thermally conductive electroconductive silicone rubber on at least one side of the sheet which is calcined and integrally composited, and thermally hardened by thermal curing Method for producing a release sheet. The method for producing a release sheet for thermocompression bonding according to claim 8, wherein the reinforcing fibers of the conductive fluororesin sheet are glass fiber fabrics. The method of claim 8, wherein the fluorine resin is tetrafluoroethylene polymer (PTFE), tetrafluoroethylene-6 fluorinated propylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (PETFE), and tetrafluoroethylene It is at least 1 resin chosen from a perfluoroalkyl vinyl ether copolymer (PFA), The manufacturing method of the release sheet for thermocompression bonding. The method for producing a release sheet for thermocompression bonding according to claim 8, wherein the conductive fluororesin sheet is a mixture of 1.0 to 15 parts by weight of carbon black based on 100 parts by weight of the fluorine resin. The method for producing a release sheet for thermocompression bonding according to claim 8, wherein the surface activation treatment is at least one kind selected from among sodium etching surface treatment, discharge surface treatment, plasma surface treatment, and ozone surface treatment. The method of manufacturing a release sheet for thermocompression bonding according to claim 8, wherein the silicone rubber is a liquid addition reaction vulcanized silicone rubber liquid at 25 ° C. The thermally conductive electrical electrically conductive silicone rubber according to claim 8, wherein 1.0 to 200 parts by weight of the metal oxide powder and 1.0 to 50 parts by weight of carbon black are mixed with respect to 100 parts by weight of the silicone rubber. Method for producing a release sheet. 9. The method for producing a release sheet for thermocompression bonding according to claim 8, wherein the heat curing conditions of the liquid thermally conductive electrically conductive silicone rubber layer are at a temperature of 80 to 120 ° C and a processing time of 2 to 20 minutes.