JP2003327655A - Sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet that is excellent in heat resistance, releasability and anti-staining properties and has ease in disposal after use. <P>SOLUTION: The sheet is formed from a crystalline aromatic polyester which comprises a block copolymer of (A) a polyester component comprising a short- chain polyester component represented by the formula (1):-CO-R<SP>1</SP>-CO-O-R<SP>2</SP>-O- and (B) a polyether component wherein the polyester component (A) and the polyether component (B) are bonded through (C) a diisocyanate component represented by the formula (2):-O-CO-NH-R<SP>3</SP>-NH-CO-O-. In the formula (1), R<SP>1</SP>denotes a 6-12C divalent aromatic hydrocarbon group and R<SP>2</SP>denotes a 2-8C alkylene group. In the formula (2), R<SP>3</SP>denotes 2-15C alkylene group, a phenylene group, a methylene group or a group formed by bonding an alkylene group and a phenylene group. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to heat resistance, releasability,
The present invention relates to a release sheet that has excellent non-staining properties and that can be easily discarded after use.

[0002]

2. Description of the Related Art In a manufacturing process of a printed wiring board, a flexible printed wiring board, a multilayer printed wiring board, etc., a release film is used when hot pressing a copper clad laminate or a copper foil through a prepreg or a heat resistant film. ing. Further, in the manufacturing process of the flexible printed circuit board, when the cover lay film is heat-pressed and bonded to the flexible printed circuit board body on which the electric circuit is formed by the thermosetting adhesive, the cover lay film and the press hot plate are bonded to each other. In order to prevent this, a method using a release film is widely used. As the release film used for these purposes, a fluorine-based film, a silicon-coated polyethylene terephthalate film, a polymethylpentene film, as disclosed in JP-A-2-175247 and JP-A-5-283862, A polypropylene film etc. are mentioned.

[0003]

[Patent Document 1] Japanese Unexamined Patent Publication No. 2-175247

[Patent Document 2] Japanese Unexamined Patent Publication No. 5-283862

In recent years, due to environmental issues and increasing social demands for safety, these release films have functions such as heat resistance to withstand hot press molding and releasability from printed wiring boards and hot press plates. In addition, there is a growing demand for ease of disposal. Further, in order to improve the product yield at the time of hot press molding, the non-contamination property to the copper circuit has also become important. However, the fluorine-based film that has been conventionally used as a release film is excellent in heat resistance, release property, and non-staining property, but it is expensive and difficult to burn in waste incineration after use, and, There was a problem of generating toxic gas. Further, the silicone-coated polyethylene terephthalate film and the polymethylpentene film may cause contamination of the printed wiring board, especially the copper circuit, by the migration of the silicone or the low molecular weight constituents, and may deteriorate the quality. Further, the polypropylene film has a problem that it has poor heat resistance and insufficient releasability.

[0005]

SUMMARY OF THE INVENTION In view of the above situation, it is an object of the present invention to provide a sheet which is excellent in heat resistance, releasability and non-staining property and which can be easily discarded after use. Is.

[0006]

The sheet of the present invention is a block copolymer of a polyester component (A) consisting of a short-chain polyester component represented by the following general formula (1) and a polyether component (B). The polyester component (A) and the polyether component (B) are bonded together by a diisocyanate component (C) represented by the following general formula (2) to form a crystalline aromatic polyester sheet. .

[0007]

[Chemical 9]

In the formula (1), R ¹ represents a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms, and R ² represents an alkylene group having 2 to 8 carbon atoms.

[0009]

[Chemical 10]

In the formula (2), R ³ represents an alkylene group having 2 to 15 carbon atoms, a phenylene group, a methylene group, or a group in which an alkylene group and a phenylene group are bonded.

The short chain polyester component of the polyester component (A) has a structure represented by the formula (1),
It is preferably derived from a reaction product of an aromatic dicarboxylic acid or an ester-forming derivative thereof and a low molecular weight diol, and more preferably derived from butylene terephthalate. By containing a component derived from a product obtained by reacting an aromatic dicarboxylic acid or its ester-forming derivative with a low molecular weight diol, the obtained sheet becomes excellent in non-staining property and crystallinity.

The polyester component (A) is composed of a repeating short-chain polyester component represented by the general formula (1) and a long-chain polyester component represented by the following general formula (3). Is preferred. By containing the long-chain polyester component, the compatibility between the polyester component (A) and the polyether component (B) is improved,
A crystalline aromatic polyester having a high degree of polymerization is obtained. As a result, the sheet has improved releasability and mechanical strength during hot press molding. The long-chain polyester component is preferably derived from a reaction product of an aromatic dicarboxylic acid or its ester and a high molecular weight diol.

[0013]

[Chemical 11]

In the formula (3), R ⁴ represents a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms, R ⁵ is composed of a repeating unit represented by —R ⁶ —O—, and R ⁶ Is an alkylene group having 2 to 8 carbon atoms.

When the polyester component (A) comprises a short-chain polyester component and a long-chain polyester component, the proportion of the short-chain polyester component is preferably 50% by weight or more. When it is less than 50% by weight, the melting point of the polyester component (A) becomes low, the heat resistance of the obtained sheet is lowered, and it becomes impossible to endure hot press molding during use.

Examples of the aromatic dicarboxylic acid or ester-forming derivative thereof include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalene dicarboxylic acid, paraphenylenedicarboxylic acid, dimethyl terephthalate, dimethyl isophthalate, dimethyl orthophthalate and naphthalene. Examples thereof include dimethyl dicarboxylate and dimethyl paraphenylene dicarboxylate. These may be used alone or in combination of two or more.

Examples of the above-mentioned low molecular weight diol include:
Ethylene glycol, 1,2-propanediol, 1,
3-propanediol, 1,3-butanediol, 1,
4-butanediol, neopentyl glycol, 1,5
-Pentanediol, 1,6-hexanediol, 1,
4-cyclohexane dimethanol etc. are mentioned. These may be used alone or in combination of two or more. Examples of the high molecular weight diol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol, polycaprolactone, polybutylene adipate and the like. These may be used alone or in combination of two or more.

The preferred range of the number average molecular weight of the polyester component (A) is 500 to 5,000. When it is less than 500, the block property of the polyester component (A) is lowered, and the melting point of the crystalline aromatic polyester is lowered,
The heat resistance of the obtained sheet decreases, and it becomes impossible to endure hot press molding during use. On the other hand, when it exceeds 5,000, the degree of polymerization of the crystalline aromatic polyester obtained does not increase because the compatibility between the raw material polyester of the polyester component (A) and the raw material polyether of the polyether component (B) is low, and the sheet The heat resistance will decrease. A more preferable range of the number average molecular weight is 500 to 3000. The number average molecular weight of the polyester component (A) is
It is equivalent to the number average molecular weight of the polyester (a) usually used as a raw material.

The polyether component (B) is preferably represented by the general formula (2) and is derived from the high molecular weight diol. The preferable range of the number average molecular weight of the polyether component (B) is 500 to 5,000. If it is less than 500, the flexibility of the crystalline aromatic polyester may be reduced, and the conformability to the uneven shape of the substrate in hot press molding may be reduced, causing a problem. Also,
When it exceeds 5,000, since the compatibility between the raw material polyether of the polyether component (B) and the raw material polyester of the polyester component (A) is poor, the degree of polymerization of the obtained crystalline aromatic polyester does not increase, and the heat resistance of the sheet is low. Will decrease. A more preferable range of the number average molecular weight is 500 to
It is 3000. The number average molecular weight of the polyether component (B) is the same as that of the polyether (b) usually used as a raw material.
It is equivalent to the number average molecular weight of. By using a low polarity polyether such as poly (1,2-butylene glycol) or a low molecular weight polyolefin-based polyol as the polyether component (B), the polarity of the crystalline aromatic polyester can be lowered, The releasability of the sheet during hot press molding is improved.

The polyisocyanate component (C) has an average number of isocyanate groups per molecule of 2.0 to
Those in the range of 2.2 are preferable. As the above-mentioned isocyanate compound having an average number of isocyanate groups of 2.0,
For example, aromatic diisocyanates such as 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate; 1,2-ethylene diisocyanate, 1,
3-propylene diisocyanate, 1,4-butane diisocyanate, 1,6-hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3
And aliphatic diisocyanates such as cyclohexane diisocyanate, isophorone diisocyanate, and hydrogenated 4,4′-phenylmethane diisocyanate.

Further, by mixing an isocyanate compound having an average number of isocyanate groups exceeding 2.2 with an isocyanate compound having an average number of isocyanate groups of 2.0, the average number of isocyanate groups per molecule is 2.0 to
You may use what was set to the range of 2.2. 1
Examples of the isocyanate compound having an average number of isocyanate groups per molecule of more than 2.2 are, for example, polymeric MDI, triphenylmethane triisocyanate (average number of isocyanate groups 3.0), tric (isocyanate phenyl) thiophosphate (average number of isocyanate groups 3.0). And hexamethylene triisocyanate (average number of isocyanate groups is 3.0). Among the above-mentioned polymeric MDIs, those commercially available include, for example, "Millionate MR200" manufactured by Nippon Polyurethane Company.
(Average number of isocyanate groups is 2.8).

To produce the crystalline aromatic polyester, the polyester (a) as a raw material of the polyester component (A), the polyether (b) as a raw material of the polyether component (B), and the above Polyisocyanate compound (c) as a raw material for the polyisocyanate component (C)
And are used. At this time, it is preferable that the polyester (a) has a hydroxyl group at both ends. By having hydroxyl groups at both ends, the above crystalline aromatic polyester can be easily produced by the following method.

The molar amount of the isocyanate group contained in the polyisocyanate compound (c) is the total molar amount of the groups containing active hydrogen contained in the polyester (a) and the polyether (b), that is, the isocyanate group. It is preferably 0.80 to 1.05 times the molar amount of the group capable of reacting with. If it is less than 0.80, the molecular weight of the crystalline aromatic polyester (D) obtained may be low, and sufficient mechanical strength may not be obtained. If it exceeds 1.05, the crystalline aromatic polyester The amount of side reaction products such as an unstable allophanate group and buret group increases, and the heat resistance decreases. As a result, the heat resistance of the sheet of the present invention during hot press molding may decrease. A more preferable molar ratio is 0.90 to 1.01.

The method for producing the crystalline aromatic polyester is not particularly limited, but the polyether (b) and the polyisocyanate compound (c) are reacted to produce a prepolymer whose both ends are isocyanated. A method of producing by a two-step process including a first process and a second process of reacting the prepolymer with the polyester (a) having hydroxyl groups at both ends is preferable. According to this method, the polyester component (A) and the polyether component (b) are not independently chain-extended by the polyisocyanate compound (c), and the polyester component (A) and the polyether component (B) can be reliably made into the polyisocyanate. A crystalline aromatic polyester consisting of a block copolymer bound by the component (C) is obtained. Further, the prepolymer and the polyester (a) are partially reacted to serve as a compatibilizing agent for the polyester (a) and the polyether (b), and thus the polyester (a) and the polyether (b).
Higher molecular weight is possible even when compatibility with is poor.

When the crystalline aromatic polyester is produced by the above two-step process, the molar amount of the isocyanate group contained in the polyisocyanate compound (c) reacts with the isocyanate group contained in the polyether (b). It is preferably 1.1 to 2.2 times the molar amount of the group containing active hydrogen to be obtained. If it is less than 1.1, both ends of the prepolymer to be produced may not be completely isocyanated and the reaction in the second step may be hindered. When it exceeds 2.2,
Second, since unreacted isocyanate compound (c) remains
A side reaction is caused at the time of reaction in the process, and side reaction products such as allophanate groups or burette groups increase, and the heat resistance of the obtained crystalline aromatic polyester and sheet decreases. A more preferable molar ratio is 1.2 to 2.0. Further, by controlling the equivalence of the polyester (a), the polyether (b) and the isocyanate compound (c), for example, an excess polyester (a) is reacted with the prepolymer in the second step. As a result, the end of the crystalline aromatic polyester obtained can be used as the polyester component (A). This makes it possible to increase the melting point of the crystalline aromatic polyester and improve the heat resistance of the sheet.

The preferable range of the reaction temperature in the first step is 100 ° C to 240 ° C. If it is less than 100 ° C, the reaction may not proceed sufficiently, and if it exceeds 240 ° C, the polyether (b) may decompose. A more preferable range is 160 ° C to 220 ° C. Second above
The preferable reaction temperature range in the step is 100 ° C to 24 ° C.
It is 0 ° C. If it is lower than 100 ° C, the reaction may not proceed sufficiently, and if it exceeds 240 ° C, the prepolymer may be decomposed and a crystalline aromatic polyester having sufficient strength may not be obtained. More preferable range is 160 ° C to 2
It is 20 ° C. In the second step, the polyester (a) may be separately melted by heating and added to the prepolymer using a pump or the like, or the polyester (a) may be melted by heating with an extruder and then the prepolymer may be added. May be. The reaction in the first step and the second step is preferably a bulk reaction. According to the bulk reaction,
In particular, the reactivity in the second step is improved.

The reaction equipment used for the above reaction is not particularly limited, and for example, a single-screw or twin-screw extruder is used, but a twin-screw extruder of the same rotation type or a different rotation is used because of the efficiency of stirring and mixing. Mold twin-screw extruders are preferred, and co-rotating intermeshing twin-screw extruders are more preferred. By using this reaction equipment, the reactivity especially in the second step is improved.
Further, in order to continuously carry out the reaction of the first step and the second step, it is preferable to use a tandem type extruder.

In the reaction in the first step and the second step, a catalyst can be used during stirring and mixing.
Examples of the catalyst include diacyl stannous, tetraacyl stannic acid, dibutyltin oxide, dibutyltin dilaurate, dimethyltin malate, tin dioctanoate, tin tetraacetate, triethyleneamine, diethyleneamine, triethylamine, naphthenic acid metal salt, Metal octylates, triisobutylaluminum, tetrabutyl titanate, calcium acetate, germanium dioxide, antimony trioxide, etc. are preferably used. These catalysts may be used alone or in combination of two or more kinds.

A stabilizer may be further added to the above crystalline aromatic polyester. Examples of the stabilizer include 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl).
Benzene, 3,9-bis {2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) -propionyloxy] -1,1-dimethylethyl} -2,4,8,1
Hindered phenolic antioxidants such as 0-tetraoxaspiro [5,5] undecane; tris (2,4-di-)
t-butylphenyl) phosphite, trilaurylphosphite, 2-t-butyl-α- (3-t-butyl-4)
-Hydroxyphenyl) -p-cumenyl bis (p-nonylphenyl) phosphite, dimyristyl 3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate, pentaerystyryl tetrakis (3-laurylthioprone Pionate), ditridecyl 3,3'-
Examples include heat stabilizers such as thiodipropionate.

In the crystalline aromatic polyester, an inorganic compound having a large aspect ratio, a fiber, an inorganic filler, a flame retardant, an ultraviolet absorber, an antistatic agent, an inorganic substance, a higher fatty acid can be used as long as the practicability is not impaired. Additives such as salt may be added. Examples of the fibers include glass fibers, carbon fibers, boron fibers, silicon carbide fibers, alumina fibers, amorphous fibers, inorganic fibers such as silicon / titanium / carbon fibers; organic fibers such as aramid fibers.

By adding the above-mentioned inorganic compound having a large aspect ratio, it becomes possible to improve the releasability at high temperature, and further it is possible to suppress the bleeding out of additives and low molecular weight substances contained in the film to the film surface. The cleanliness during hot press molding can be improved. Examples of such inorganic compounds include layered silicates such as clay and layered double hydrates such as hydrotalcite.

Examples of the inorganic filler include calcium carbonate, titanium oxide, mica, talc and the like. Examples of the flame retardant include hexabromocyclododecane, tris- (2,3-dichloropropyl) phosphate, pentabromophenyl allyl ether, and the like. Examples of the ultraviolet absorber include pt
-Butylphenyl salicylate, 2-hydroxy-4-
Methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,4,5-trihydroxybutyrophenone and the like can be mentioned. Examples of the antistatic agent include N, N-bis (hydroxyethyl) alkylamine, alkylallyl sulfonate,
Alkyl sulfanates and the like can be mentioned. Examples of the inorganic material include barium sulfate, alumina, silicon oxide and the like. Examples of the higher fatty acid salt include sodium stearate, barium stearate, sodium palmitate and the like.

The crystalline aromatic polyester may further contain other thermoplastic resins, rubber components and the like. Examples of the other thermoplastic resin include polyolefin, modified polyolefin, polystyrene, polyvinyl chloride, polyamide, polycarbonate, polysulfone, polyester, and the like.

Examples of the rubber component include natural rubber, styrene-butadiene copolymer, polybutadiene,
Polyisoprene, acrylonitrile-butadiene copolymer, ethylene-propylene copolymer (EPM, EPD
M), polychloroprene, butyl rubber, acrylic rubber,
Examples thereof include silicone rubber, urethane rubber, olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, vinyl chloride-based thermoplastic elastomer, ester-based thermoplastic elastomer, and amide-based thermoplastic elastomer.

The sheet of the invention according to claim 1 has a storage elastic modulus at 23 ° C. of 1000 to 5000 MPa,
The storage elastic modulus at C is 20 MPa to 200 MPa.
When the storage elastic modulus at 23 ° C. is less than 1000 MPa,
Since the mechanical strength at room temperature decreases, the strength becomes insufficient in the peeling process after press molding, and the handleability of the sheet or film at room temperature decreases. Conversely 500
If it exceeds 0 MPa, the followability to the uneven shape during press molding is adversely affected. Further, if the storage elastic modulus at 170 ° C. is less than 20 MPa, it may not be possible to develop heat resistance that can withstand hot press molding, and 200 MPa
If the value exceeds the range, the mold release film will not be sufficiently deformed during hot press molding, resulting in poor followability to circuit patterns, through holes and other irregularities on the substrate. Adhesion may deteriorate. More preferably 2
It is 0 MPa to 150 MPa.

The sheet of the invention according to claim 2 has a tear strength at 23 ° C. of 98 N / mm or more and a 100% elongation load at 170 ° C. of 0.05 to 0.5 N / mm. If the tear strength at 23 ° C. is less than 98 N / mm, when used as a release film, the strength may be insufficient in the peeling step after pre-molding, and resin may adhere to the circuit. Such resin adhesion to the circuit board significantly reduces the conductivity, and the entire printed board becomes a defective product. The tear strength is J
It is a value measured according to IS K 7128 C method (right angle tearing method). Also, 100% at 170 ° C
When the elongation load is less than 0.05 N / mm, when used as a release film, the heat resistance is insufficient and the heat press molding cannot be endured. On the other hand, if it exceeds 0.5 N / mm, it is not sufficiently deformed during hot pressing, so that the followability to the circuit pattern, through holes, and other irregularities on the substrate is deteriorated. For example, the uniform adhesion of the cover lay film to the circuit pattern on the flexible printed circuit board deteriorates. The 100% elongation load is the load when the strain reaches 100% in the tensile test.
It is a value measured according to K 7127.

170 ° C. of the sheet according to the invention of claim 3
The storage elastic modulus at 20 MPa to 200 MPa is 1
The tensile elongation at break at 70 ° C is 500% or more, 170
The dimensional change rate is 1.5% or less when pressure is applied for 60 minutes at a temperature of 3 MPa. If the tensile elongation at break at 170 ° C. is less than 500%, the release film may be torn when following the uneven shape on the substrate during hot press molding, and the substrate may be contaminated. It is preferably at least 800%. Further, at 170 ° C., the dimensional change rate is 1.5% or less when pressure is applied for 60 minutes under a load of 3 MPa. 1.
If it exceeds 5%, the circuit pattern may be damaged during hot press molding. It is preferably 1.0% or less.

The heat of crystal fusion of the sheet of the present invention is 40 J /
It is preferably at least g. Heat of fusion of sheet is 40J
If it is less than / g, the degree of crystallinity is low, the proportion of disordered crystals increases, and cold crystallization may occur due to the thermal history during hot press molding. As a result, the dimensional change rate at the time of hot press molding increases, and the circuit pattern may be damaged. More preferably, it is 50 J / g or more. In order to improve the crystallinity and obtain a high heat of crystal fusion, an additive such as a crystal nucleating agent that promotes crystallization may be added to the resin composition, and further, the cooling temperature at the time of melt molding of the sheet,
It is preferable to set the temperature above the glass transition temperature of the aromatic polyester, and more preferably set to 70 to 150 ° C. The heat of crystal fusion can be measured by differential scanning calorimetry.

The outgas amount at 170 ° C. of the sheet of the present invention is preferably 200 ppm or less. 200
When it exceeds ppm, when the sheet of the present invention is used as a release film, the substrate and electrodes may be contaminated. In addition, the above-mentioned outgas was measured by using GC-MS.
The gas generated from the film was heated at 0 ° C. for 10 minutes and separated using a non-polar capillary column, and the toluene-equivalent amount of the detected peak total area was standardized by the film weight to obtain the outgas amount.

The thickness of the sheet of the present invention is not particularly limited, but it is preferably 5 to 300 μm. If it is less than 5 μm, the strength tends to be insufficient, and if it exceeds 300 μm, the thermal conductivity during hot press molding may deteriorate.
A more preferable thickness is 10 to 50 μm.

The surface of the sheet of the present invention preferably has smoothness, but slipperiness necessary for handling,
An anti-blocking property may be imparted, and an appropriate embossed pattern may be provided on at least one surface for the purpose of releasing air during hot press molding.

The sheet of the present invention can be produced by a melt molding method. The melt molding method is not particularly limited, for example, air-cooled or water-cooled inflation extrusion method,
A conventionally known method for forming a thermoplastic resin film, such as a T-die extrusion method, may be used. The sheet of the present invention may be heat-treated in order to improve heat resistance, releasability and dimensional stability. The treatment temperature is more effective as the temperature is lower than the melting point of the resin composition constituting the film, and the treatment temperature is more effective, preferably 170 ° C. or higher, and more preferably 200 ° C. or higher. Further, as other methods for improving heat resistance, releasability, and dimensional stability, a method of uniaxially or biaxially stretching the sheet of the present invention, a method of rubbing the surface of the sheet with a buff roll, or the like can be given. .

The sheet of the present invention may be a multilayer sheet having a multilayer structure in which another resin layer is laminated on one side of the sheet. Other resin layers may be appropriately laminated depending on the application, and for example, a multilayer sheet in which a resin film is laminated on one surface of the above-mentioned sheet has cushioning properties for uniformly applying pressure during hot press molding and When used as a release sheet in the production of a flexible printed circuit board, the release sheet has high strength and is excellent in uniform adhesion to the circuit pattern of the coverlay film.

The above resin film is not particularly limited, but polyethylene resin,
A resin made of an olefin resin such as a polypropylene resin, an ethylene-methyl methacrylate copolymer, or an ethylene-vinyl acetate copolymer is preferable. These may be used alone or in combination of two or more. Also,
In order to improve the adhesiveness with a sheet, a modified polyolefin such as an acid-modified polyolefin or a glycidyl-modified polyolefin, or a resin composition constituting the sheet may be blended in the resin film. The melting point of the resin film is preferably 50 ° C. to 130 ° C. in order to prevent the prepreg or the thermosetting adhesive from seeping into the through holes and to obtain uniform adhesion to the circuit pattern. In order to obtain uniform adhesion to the circuit pattern, the composition constituting the resin film preferably has a complex viscosity at 170 ° C. of 100 Pa · s to 10000 Pa · s.

In the multilayer sheet of the present invention, in order to improve the adhesion between the sheet and the resin film, the modified polyolefin or the resin composition constituting the sheet and the resin composition constituting the resin film are provided between the sheet and the resin film. You may provide the adhesive resin layer which consists of a blended product.

In the multilayer sheet of the present invention, the sheet laminated with the above resin film has a thickness of 0.5 to 100 μm.
Is preferred. If it is less than 0.5 μm, the strength tends to be insufficient, and if it exceeds 100 μm, the thermal conductivity may decrease and the cost also increases. Further, the thickness of the multilayer sheet of the present invention is preferably 5 to 300 μm. If it is less than 5 μm, the strength tends to be insufficient, and if it exceeds 300 μm, the thermal conductivity during hot press molding may deteriorate. More preferably, it is 25 to 200 μm.

The softening temperature of the multilayer sheet of the present invention is 40 to 120 in order to prevent the prepreg and the thermosetting adhesive from seeping into the through holes and to obtain a uniform adhesion to the circuit pattern. C. is preferred. The softening temperature of the film is JIS K 7196.
It is the value measured by the method according to.

The method for producing the multilayer sheet of the present invention is not particularly limited, and examples thereof include a water-cooled or air-cooled coextrusion inflation method, a method of forming a film by a coextrusion T-die method, and a resin forming a resin film on the sheet. Examples thereof include a method of laminating the composition by an extrusion lamination method, a method of dry laminating a sheet and a resin film, a solvent casting method, a hot press molding method and the like. Among them, the method of forming a film by the coextrusion T-die method is preferable because it is excellent in controlling the thickness of each layer.

The multilayer sheet of the present invention has heat resistance, releasability,
Heat treatment may be performed to improve dimensional stability. If the treatment temperature is lower than the melting point of the resin composition constituting the multilayer sheet, the higher the temperature is, the more effective it is.
170 ° C or higher is preferable, and 200 ° C or higher is more preferable. As a method of improving heat resistance, releasability, and dimensional stability, a method of rubbing the surface of the multilayer sheet with a buff roll or the like can be mentioned.

Since the sheet of the present invention is made of a non-halogenated crystalline resin composition having an aromatic ring structure in the main chain of which crystalline aromatic polyester is an essential component, high heat resistance can be exhibited. And also has excellent mechanical properties. Furthermore, the environmental load at the time of disposal is small. Further, the crystalline aromatic polyester has a short-chain polyester component-rich portion and a polyether component-rich portion in the molecule, and since the short-chain polyester component has a high block property and high crystallinity, the conventional It is a polyester material that is more flexible than crystalline aromatic polyester that exhibits some heat resistance.

Further, since the sheet of the present invention has a specific melting point and storage elastic modulus, the molecular motion of film constituent molecules at the hot press molding temperature is suppressed,
It becomes possible to express excellent releasability. Further, since the release film of the present invention has a specific storage elastic modulus and tensile elongation at break, it has both easy deformability and strength at the hot press molding temperature, and is excellent in the unevenness of the circuit pattern. It is possible to exhibit conformability and prevent the cushion layer resin from leaking to the substrate surface. Furthermore, since the release film of the present invention has high crystallinity, cold crystallization at the hot press molding temperature is suppressed, dimensional stability is improved, and it is possible to suppress defects such as circuit pattern displacement. Become. Thus, by using the release film of the present invention,
The product yield at the time of hot press molding in the production of printed wiring boards can be dramatically improved.

The sheet of the present invention is used for hot-pressing a copper-clad laminate or copper foil through a prepreg or heat-resistant film in a manufacturing process of a printed wiring board, a flexible printed wiring board, a multilayer printed wiring board, etc. Heat plate and printed wiring board, flexible printed wiring board,
It is preferably used as a release sheet that prevents adhesion to a multilayer printed wiring board or the like. Further, in the manufacturing process of the flexible printed circuit board, when the coverlay film is bonded by a thermosetting adhesive by heat pressing, the coverlay film and the heat press plate, or as a release sheet for preventing adhesion between the coverlay films. Is also preferably used.

Furthermore, when manufacturing prepregs made of glass cloth, carbon fiber, or aramid fiber and epoxy resin in an autoclave, the fishing rods, sports equipment such as golf clubs and shafts, and aircraft parts are manufactured. It is also useful as a release sheet in the production of release sheets, polyurethane foam, ceramic sheets, electric insulating plates and the like.

[0054]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. [Synthesis of Polyester (a-1)] 100 parts by weight of dimethyl terephthalate, 102 parts by weight of 1,4-butanediol, 0.3 parts by weight of tetrabutyl titanate as a catalyst,
0.33 parts by weight of 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene as a stabilizer, and tris (2,4-di) 0.3 part by weight of -t-butylphenyl) phosphite was added, and the reaction system was kept under nitrogen at 200 ° C for 3 hours to carry out a transesterification reaction. The progress of the transesterification reaction was confirmed by measuring the amount of distilled methanol. After the transesterification reaction, the temperature was raised to 240 ° C. in 20 minutes, and the pressure was reduced. The polymerization system reached a degree of reduced pressure of 270 Pa or less in 15 minutes. As a result of polycondensation reaction for 60 minutes in this state, 113 parts by weight of white polyester was obtained. This was made into polyester (a-1). Polyester (a-
For 1), using a gel permeation chromatography (manufactured by Tosoh Corporation: HLC 8020 series), a column; S
The number average molecular weight was 3500 when the number average molecular weight was measured under the conditions of two hodex HFIP 806M, a solvent; hexafluoroisolopanol (0.005N sodium trifluoroacetate added), and a standard; polymethylmethacrylate.

[Synthesis of Polyester (a-2)] In the synthesis of polyester (a-1), the number average molecular weight is about 6
50 polytetramethylene glycol (P made by Mitsubishi Chemical Corporation
TMG650) except that 12 parts by weight are added,
126 parts by weight of white polyester was obtained. This was made into polyester (a-2). The number average molecular weight of the polyester (a-2) was 3,500.

[Synthesis of Polyester (a-3)] In the synthesis of polyester (a-2), the number average molecular weight is about 6
50 polytetramethylene glycol (P made by Mitsubishi Chemical Corporation
240 parts by weight of white polyester were obtained in the same manner except that TMG650) was changed to 170 parts by weight. This was made into polyester (a-3). The number average molecular weight of the polyester (a-3) was 3,700.

[Synthesis of Polyester (a-4)] White polyester 126 was prepared in the same manner as in the synthesis of polyester (a-2) except that the condensation time was 120 minutes.
Parts by weight were obtained. This was made into polyester (a-4).
The number average molecular weight of the polyester (a-4) was 6,500.

[Production of Resin Film] Low-density polyethylene resin (manufactured by Nippon Polychem: Novatec LD LE42
5) was melt-plasticized by heating at 230 ° C. with an extruder and extrusion-molded from a T-die to obtain a resin film having a thickness of 100 μm. [Production of copper-clad laminate] A 25 μm thick polyimide film (DuPont: Kapton) was used as a base film,
A copper-clad laminate having a copper foil having a thickness of 35 μm and a width of 50 μm bonded to the base film with an epoxy adhesive layer having a thickness of 20 μm was prepared. [Preparation of Coverlay Film] A 25 mm-thick polyimide film (Kapton manufactured by DuPont) was coated with an epoxy adhesive having a flow starting temperature of 80 ° C. in a thickness of 20 μm to obtain a coverlay film.

Example 1 Synthesis of Crystalline Aromatic Polyester 10 parts by weight of polytetramethylene glycol having a number average molecular weight of 1000 as the polyether (b) and 4,4'-diphenylmethane diisocyanate as the polyisocyanate compound (C) 9.6 parts by weight and a twin-screw extruder (manufactured by Toshiba Machine Co., L /
D = 58) from the first barrel, and 100 parts by weight of polyester (a-1) from four barrels of the extruder were fed using a forced side feeder, and melt-mixed at 230 ° C. to give a crystalline aromatic compound. I got polyester. [Production of Sheet] Using the obtained crystalline aromatic polyester, it was melt-plasticized at 230 ° C. by an extruder and extrusion-molded from a T-die to obtain a film having a thickness of 50 μm. [Production of Flexible Printed Circuit Board] Using the above film as a release sheet, a flexible printed circuit board was produced by the following method. A set of a release sheet, a copper-clad laminate, a coverlay film, a release sheet, and a resin film stacked in this order (see FIG. 1) is set as 32 sets, and 32 sets are placed on a hot press at a press temperature of 170 ° C. , Press pressure 3
After hot press molding under the conditions of 00 N / cm ² and a pressing time of 60 minutes, the press pressure was released, the resin film was removed, and the release sheet was peeled off to prepare a flexible printed circuit board.

Example 2 Polytetramethylene glycol 2 having a number average molecular weight of 1000 as the polyether (b)
5.4 parts by weight of 4,4′-diphenylmethane diisocyanate as the polyisocyanate compound (C) was used.
A crystalline aromatic polyester was obtained in the same manner as in Example 1 except that 4 parts by weight was used. Next, in the same manner as in Example 1, a film was prepared and a flexible printed board was prepared.

Example 3 A polyester (a-2) was used in place of the polyester (a-1), except that
A crystalline aromatic polyester was obtained in the same manner as in Example 1. Next, in the same manner as in Example 1, a film was prepared and a flexible printed board was prepared.

(Example 4) Example 1 using Perprene P150B (crystalline aromatic polyester, manufactured by Toyobo Co., Ltd.)
A film was prepared in the same manner as in 1. to prepare a flexible printed circuit board.

Example 5 Polyester (a-4) was used in place of polyester (a-1), and 6.3 parts by weight of 4,4'-diphenylmethane diisocyanate was used as polyisocyanate compound (c). A crystalline aromatic polyester was obtained in the same manner as in Example 1 except for the above. Next, in the same manner as in Example 1, a film was prepared and a flexible printed board was prepared.

Comparative Example 1 Polyester (a-3) was used in place of polyester (a-1), and 9.2 parts by weight of 4,4'-diphenylmethane diisocyanate was used as polyisocyanate compound (c). A crystalline aromatic polyester was obtained in the same manner as in Example 1 except for the above. Next, in the same manner as in Example 1, a film was prepared and a flexible printed board was prepared.

Comparative Example 2 A sheet having a thickness of 50 μm
A flexible printed circuit board was prepared in the same manner as in Example 1 by using the above-mentioned Uran X-88B (polymethylpentene, manufactured by Mitsui Chemicals, Inc.).

[Evaluation] In Examples 1 to 5 and Comparative Examples 1 and 2.
About the produced film, the melting point and binding
Crystal fusion heat, storage elastic modulus, tensile elongation at break and dimensional change rate
Was measured. In addition, these films are used as release sheets.
The flexible printed circuit board used for
Peelability and adhesion of mold film and flexibility after fabrication
Whether the electrodes of the printed circuit board are contaminated or the circuit is deformed
The usability was evaluated. The results are shown in Table 1. (Melting point, heat of fusion of crystal) Differential scanning calorimeter (DSC 29
20, manufactured by TA Instruments) using a heating rate of 5
The measurement was performed at ° C / min. (Measurement of storage elastic modulus) Viscoelasticity spectrometer (RS
A-11, Rheometric Scientific F
-Manufactured), heating rate 5 ° C / min, frequency 1.61H
z, strain 0.05%, measured at 170 ° C
The storage elastic modulus was measured. (Measurement of tensile elongation at break) According to JIS K 7127
For the punched test piece of test piece type 5, 170
It was measured at a test temperature of 500 mm / min. (Measurement of rate of dimensional change) Extrusion molding on the surface of release film
Direction (MD direction) and the direction perpendicular to it (TD direction)
Orientation) is marked with 100 mm interval marked lines. Mold release
Press the film at 170 ℃, load 3MPa for 60 minutes
After that, the distance between marked lines was measured. 32 above measurement
Performed for each set and set the average value (Lmm) for each to L
_MD, L _TDAnd the dimensional change rate in each direction according to the following formula
Was calculated.

[0067] Dimensional change rate (%) = (L-100) / 100 × 100

(Releasability of Release Film) The state of releasing the release film after pressing from the flexible printed board was observed. (Adhesion) The adhesive state between the flexible printed board and the coverlay film was visually observed. By observing the above-mentioned adhesion state, it can be evaluated whether or not the release sheet is in close contact with the coverlay film and closely follows the unevenness of the circuit portion of the flexible printed board. (Electrode Contamination) The presence or absence of contamination due to the adhesion of organic substances or the like due to the seepage of the adhesive from the coverlay film on the surface of the copper foil of the electrode portion of the flexible printed circuit board was visually observed. The state of contamination of the copper foil portion is a measure of the adhesion of the release sheet to the cover lay sheet and the copper foil. That is,
If the adhesion is good, the exudation of the adhesive can be prevented and contamination does not occur. (Circuit Deformation) Whether or not the copper foil on the electrode portion of the flexible printed board was deformed was visually observed.

[0069]

[Table 1]

[0070]

According to the present invention, it is possible to provide a release film which is excellent in heat resistance, releasability and non-staining property and which can be easily discarded after use.

[0071]

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a stacking order when a flexible printed circuit board is manufactured in an example.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // C08L 75:04 C08L 75:04 F term (reference) 4F071 AA53 AA87 AF16 AF20 AF21 AF54 AH13 BA01 BB06 BC01 4F100 AK01B AK01C AK43A AL02A BA02 BA03 GB43 JA11A JJ03 JK03A JK06 JK07A JK08A JL06 YY00A 4J034 DA01 DB04 DF01 DF16 DF21 DG05 HA07 HC03 HC12 HC13 HC17 HC01 JA05 JA42 JA01 JA01 JA42 JA42 JA01A01B42

Claims (20)

[Claims] 1. A block copolymer of a polyester component (A) containing a short-chain polyester component represented by the following general formula (1) and a polyether component (B), wherein the polyester component (A): A sheet comprising a crystalline aromatic polyester in which the polyether component (B) and the polyether component (B) are bound by a diisocyanate component (C) represented by the following general formula (2), wherein the sheet is stored at 23 ° C. Elastic modulus is 1000 to 5000 MPa, and 17
A sheet having a storage elastic modulus at 0 ° C. of 20 to 200 MPa. [Chemical 1] In formula (1), R ¹ represents a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms, and R ² represents an alkylene group having 2 to 8 carbon atoms. [Chemical 2] In formula (2), R ³ represents an alkylene group having 2 to 15 carbon atoms, a phenylene group, a methylene group, or a group in which an alkylene group and a phenylene group are bonded. 2. A block copolymer of a polyester component (A) containing a short-chain polyester component represented by the following general formula (1) and a polyether component (B), wherein the polyester component (A): A sheet comprising a crystalline aromatic polyester (D) in which the above-mentioned polyether component (B) and a diisocyanate component (C) represented by the following general formula (2) are bonded, and the sheet has a temperature of 23 ° C. Tear strength at 98 N / mm or more, and 17
100% elongation load at 0 ° C is 0.05 to 0.5 N /
A sheet having a size of mm. [Chemical 3] In formula (1), R ¹ represents a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms, and R ² represents an alkylene group having 2 to 8 carbon atoms. [Chemical 4] In formula (2), R ³ represents an alkylene group having 2 to 15 carbon atoms, a phenylene group, a methylene group, or a group in which an alkylene group and a phenylene group are bonded. 3. A block copolymer of a polyester component (A) containing a short-chain polyester component represented by the following general formula (1) and a polyether component (B), wherein the polyester component (A): And a polyether component (B) are bound by a diisocyanate component (C) represented by the following general formula (2), the sheet comprising a crystalline aromatic polyester, and the sheet is stored at 170 ° C. The elastic modulus is 20 to 200 MPa, the tensile elongation at break at 170 ° C. is 500% or more, and the dimensional change rate when pressed at 170 ° C. under a load of 3 MPa for 60 minutes is
A sheet characterized by being 1.5% or less. [Chemical 5] In formula (1), R ¹ represents a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms, and R ² represents an alkylene group having 2 to 8 carbon atoms. [Chemical 6] In formula (2), R ³ represents an alkylene group having 2 to 15 carbon atoms, a phenylene group, a methylene group, or a group in which an alkylene group and a phenylene group are bonded. 4. The polyester component (A) is constituted by repeating a short chain polyester component represented by the following general formula (1) and a long chain polyester component represented by the following general formula (3). The sheet according to any one of claims 1 to 3, wherein the chain polyester component is 50% by weight or more. [Chemical 7] In formula (1), R ¹ represents a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms, and R ² represents an alkylene group having 2 to 8 carbon atoms. [Chemical 8] In formula (3), R ⁴ represents a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms, R ⁵ is composed of a repeating unit represented by —R ⁶ —O—, and R ⁶ has 2 carbon atoms. ~ 8 alkylene groups. 5. A polyester component (A) having a number average molecular weight of 500 to 5,000.
The sheet according to any one of 4 above. 6. The sheet according to claim 1, wherein the short chain polyester component of the polyester component (A) is derived from butylene terephthalate. 7. The polyether component (B) has a number average molecular weight of 500 to 5,000.
The sheet according to any one of 6. 8. The sheet according to claim 6, which has a crystal fusion heat of 40 J / g or more. 9. The sheet has a multilayer structure of three or more layers, and at least one of the intermediate layers has a storage elastic modulus at 170 ° C. lower than that of the surface layer at 170 ° C. The sheet according to claim 1. 10. The sheet has a two-layer structure, and the storage elastic modulus at 170 ° C. of one layer is lower than the storage elastic modulus at 170 ° C. of the other layer.
The sheet according to any one of 3 above. 11. The polyester component (A) is composed of a repeating short-chain polyester component represented by the following general formula (1) and a long-chain polyester component represented by the following general formula (3). The sheet according to claim 9 or 10, wherein the chain polyester component is 50% by weight or more. 12. The polyester component (A) has a number average molecular weight of 500 to 5,000.
The sheet according to any one of 1 to 11. 13. The sheet according to any one of claims 9 to 12, wherein the short chain polyester component of the polyester component (A) is derived from butylene terephthalate. 14. The polyether component (B) has a number average molecular weight of 500 to 5,000.
The sheet according to any one of 1 to 13. 15. The sheet according to claim 13, wherein the heat of fusion of crystal is 40 J / g or more. 16. The composition has a releasability with respect to the polyimide and / or metal foil when superposed on the polyimide and / or metal foil and pressed at 170 ° C. and 3 MPa for 60 minutes. The sheet according to any one of Items 9 to 15. 17. The sheet according to claim 1, wherein the amount of outgas generated at 170 ° C. of the sheet is 200 ppm or less. 18. A release sheet comprising a resin film and the sheet according to claim 1 laminated on at least one surface of the resin film. 19. A press hot plate for hot pressing a copper clad laminate or a copper foil with a prepreg or a heat-resistant film in a manufacturing process of a printed wiring board, a flexible printed wiring board, or a multilayer printed wiring board. And printed wiring board, flexible printed wiring board, or
The release film according to any one of claims 1 to 18, which is a release film that prevents adhesion to a multilayer printed wiring board. 20. In the process of manufacturing a flexible printed circuit board, when the cover lay film is adhered with a thermosetting adhesive by hot press molding, the cover lay film and the heat press plate or the cover lay films are prevented from adhering to each other. It is a release film, The release film as described in any one of Claims 1-19.