TW201441028A - Mold release film and method for using mold release film - Google Patents

Abstract

Provided is a mold release film which is capable of providing a molded product having excellent property by suppressing reacting the functional group of material forming the releasing surface of the mold release film with the material forming objective surface on which the mold release film is applied thereby interact with each other. Such a mold release film is the mold release film (10) having the mold releasing layer (1) containing polyester resin material, in which the amount of terminal carboxylic acid measured by indicator titrimetry using the mold releasing layer (1) is 40 or less, or the mold release film (30) having the mold releasing layer (21) containing polyester resin material, in which the intrinsic viscosity of the mold releasing layer (21) measured at 35 DEG C according to ASTM D2857 ranges from 0.9 to 1.5.

Description

Release film and use method of release film

The present invention relates to a method of using a release film and a release film.

The priority is claimed in Japanese Patent Application No. 2013-119653, filed on Jan.

Examples of the release film include the following.

Patent Document 1 discloses a release film having a polyester-based elastomer layer which exhibits a specific value for a glass transition temperature and a crystallization rate index, and a polyester aromatic layer which is blended with a specific mass ratio. The polyester and 1,4-cyclohexanedimethanol copolymerized polyethylene terephthalate are formed of a polyester exhibiting a specific value for the glass transition temperature and the heat of crystal melting. According to the release film described in Patent Document 1, it is excellent in flexibility, mold release property, heat resistance, and non-contamination property, and in particular, the embedability of a printed circuit board having a precise pattern is good, and in winding or A release film excellent in workability when trimming a sheet.

Patent Document 2 discloses a release film having a crystalline polyester layer which exhibits a specific value for crystal heat of fusion and a crystallization rate index, and a polyester layer which exhibits a specific value for the heat of crystal melting and the crystallization rate index. . According to the release film described in Patent Document 2, it is excellent in flexibility, mold release property, heat resistance, and non-contamination property, especially for printing with a precise pattern. A mold release film having a good landfilling ability and excellent handling workability when winding or cutting a sheet.

Patent Document 3 discloses a release film having a polyester-based elastomer layer exhibiting a specific value for a glass transition temperature and a crystallization rate index, a crystallization start temperature at a temperature rise, a temperature rise crystallization peak temperature, and a temperature rise crystallization. The heat shows a specific value of the copolymerized polyester layer. According to the release film described in Patent Document 3, it is excellent in flexibility, mold release property, heat resistance, and non-contamination property, and in particular, it can have a high degree of landfill ability and mold release property for a printed circuit board having a precise pattern. And a release film excellent in handling workability when winding or cutting a sheet.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2011-88351

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2011-88352

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2011-245812

The release film described in Patent Documents 1 and 2 and the like is required to satisfy the following four characteristics in a balanced manner.

(1) After the heat molding, the release film (release property) can be easily peeled off from the wiring substrate.

(2) In the peripheral portion of the wiring substrate, the release films adhered to each other are easily peeled off from each other (low self-melting property).

(3) During heat molding, the unevenness of the circuit wiring provided on the surface of the substrate is favorably followed, and buried in the circuit wiring to prevent the adhesive which has leaked from the cover lay-up into the circuit wiring (good landfill capability) .

(4) Good compatibility with the blended resin of the release film.

However, in recent years, the technical level required for various characteristics of the release film has been increasing.

The inventors of the present invention have found the following problems with respect to the release film.

The present inventors have found a new problem: when the release film described in Patent Documents 1 to 3 is used, the functional group of the material of the release surface of the release film is formed during hot pressing, and the object of the release film is formed. The reaction of materials on the surface of the object and the interaction. At this time, after the release film is peeled off, a part of the release film remains as a contaminant, and a good molded article cannot be obtained.

In view of the above circumstances, the present invention provides a release film which inhibits the reaction and interaction of a functional group of a material which forms a release surface of a release film during hot pressing with a material which forms a surface on which an object of the release film is disposed, A molded article of good quality can be obtained.

The present inventors have continually studied in order to achieve the above-mentioned problems, and as a result, it has been found that when a release film having a release layer containing a polyester resin material is formed, a terminal carboxylic acid measured by an indicator titration method using a release layer is used. The scale of the quantity is effective as such a design policy, and the present invention has been achieved.

According to the present invention, there is provided a release film comprising a release film comprising a release layer of a polyester resin material, wherein the amount of terminal carboxylic acid measured by an indicator titration method using the above release layer is less than 40.

Furthermore, according to the present invention, there is provided a method of using a release film comprising the steps of disposing the release film on an object and hot pressing the object to which the release film is disposed, In the above step of disposing the release film, the surface of the object to which the release film is disposed is formed of a material containing a thermosetting resin in a semi-hardened state.

In addition, the present inventors have continually studied in order to achieve the above problems, and as a result, found that the intrinsic viscosity of the release layer measured at 35 ° C according to ASTM D2857 when forming a release film having a release layer containing a polyester resin material. The scale is effective as this design policy, and the achievement of this issue Bright.

According to the present invention, there is provided a release film comprising a release film comprising a release layer of a polyester resin material, wherein the release layer has an intrinsic viscosity of 0.9 or more and 1.5 or less as measured according to ASTM D2857 at 35 ° C. .

Furthermore, according to the present invention, there is provided a method of using a release film comprising the steps of disposing the release film on an object and hot pressing the object to which the release film is disposed, In the above step of disposing the release film, the surface of the object to which the release film is disposed is formed of a material containing a thermosetting resin in a semi-hardened state.

According to the present invention, it is possible to provide a release film which can inhibit the reaction of a functional group of a material which forms a release surface of a release film during hot pressing with a material which forms a surface of an object on which the release film is disposed, and can have Good quality molded products.

1, 21‧‧‧ release layer

2, 22‧‧‧ buffer layer

3, 23‧‧‧ release layer

10, 30‧‧‧ release film

Fig. 1 is a cross-sectional view showing a release film according to a first embodiment of the present invention.

Fig. 2 is a cross-sectional view showing a release film according to the first embodiment of the present invention.

Fig. 3 is a cross-sectional view showing a release film according to a second embodiment of the present invention.

Fig. 4 is a cross-sectional view showing a release film according to a second embodiment of the present invention.

(First embodiment)

Hereinafter, the first embodiment of the present invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and the description is omitted as appropriate.

<release film>

The release film 10 of the present embodiment has a release film 10 comprising a release layer 1 of a polyester resin material, and the amount of terminal carboxylic acid measured by an indicator titration method using the release layer 1 is less than 40. Thereby, the release film 10 can be obtained, which suppresses the reaction and interaction of the functional group of the material which forms the release surface of the release film 10 at the time of hot pressing with the material which forms the surface of the object which arrange|positions the said release film 10, and can obtain it. A molded product of good quality.

In the release film 10 of the present embodiment, the release layer 1 is a resin which forms a surface of the object to be contacted (hereinafter also referred to as a "release surface") when at least the release film 10 is placed on the object. The polyester resin is a polycondensate of a polyvalent carboxylic acid (dicarboxylic acid) and a polyhydric alcohol (diol), and is a compound having a plurality of carboxyl groups (-COOH).

Moreover, the surface of the object before the release film 10 is usually formed by a material containing a thermosetting resin in a semi-hardened state. The release film 10 of the present embodiment is used by being disposed on the surface of an object formed of a material containing the thermosetting resin in the semi-hardened state. Further, by performing hot pressing in a state in which the release film 10 is placed on the surface of the object, a molded article can be obtained.

When a conventional release film is used, it is presumed that the following phenomenon occurs.

It is considered that in the conventional hot pressing, the carboxyl group in the material forming the release surface in the release film reacts with and interacts with the unreacted functional groups of the cover film adhesive. Such an unreacted functional group is not particularly limited, and examples thereof include an epoxy group which is a functional group which is easy to interact with.

Hereinafter, a case where the unreacted functional group is an epoxy group will be described as an example.

When the conventional release film described in Patent Documents 1 to 3 and the like is used, the reason why a part of the release film remains as a contaminant in the cover film is not clear, and it is considered that the polar group such as a carboxyl group is related to the contamination of the molded article. .

Further, the amount of the terminal carboxylic acid measured by the indicator titration method using the release layer of the conventional release film described in Patent Documents 1 to 3, etc., is different from the technique of the release film 10 of the present embodiment. level. As described above, when the polyester resin material contained in the conventional release film is used, it is not possible to sufficiently prevent the unreacted functional group from reacting with and interacting with a polar group (for example, a carboxyl group) in the material forming the surface of the object.

On the other hand, according to the release film 10 of the present embodiment, the amount of the terminal carboxylic acid measured by the indicator titration method using the release layer 1 of the release film 10 satisfies the above specific conditions, so that a very small amount can be suppressed. A part of the foreign matter or the release film 10 is adhered to the surface of the molded article obtained by peeling the release film 10 from the molded body obtained by hot pressing, and it is possible to obtain a mold release property which is excellent in height to prevent the surface of the molded article from being rough. It is considered that this is because a material having a value of a terminal carboxylic acid having a value of less than 40 as measured by an indicator titration method by using the release layer 1 of the release film 10 is used as a material for forming a release surface, so that The amount of carboxyl groups which react with and react with unreacted functional groups present on the surface of the molded article is less than that of the prior art. Therefore, the release film 10 of the present embodiment can obtain a highly excellent mold release property as compared with the conventional release film.

Further, the roughness generated on the surface of the molded article after hot pressing means that one part of the surface of the molded article has undulations, one part of the surface of the molded article is festered, the shape of the surface of the molded article is not smooth, and the state is rough.

Further, the amount of the terminal carboxylic acid measured by the indicator titration method using the release layer 1 of the release film 10 of the present embodiment is preferably less than 40, more preferably 25 or less. Thereby, the functional group of the material which forms the release surface of the release film 10 at the time of hot pressing can be suppressed and reacted with the material which forms the surface of the object which arrange|positions the said release film 10, and the molded object of the favorable quality is obtained.

Further, the polyester resin material in the present embodiment is not particularly limited, and examples thereof include polyethylene terephthalate resin, polybutylene terephthalate resin, polytrimethylene terephthalate resin, and poly A polyalkylene terephthalate resin such as a hexylene phthalate resin. Among these, it is preferred to use a polybutylene terephthalate resin. Thereby, the functional group of the material which forms the release surface of the release film 10 at the time of hot pressing can be suppressed and reacted with the material which forms the surface of the object which arrange|positions the said release film 10, and the molded object of the favorable quality is obtained.

Further, the polyester resin material may be a polyester-based copolymer resin in which other components are copolymerized as needed. Examples of the copolymerization component include a well-known acid component, an alcohol component, a phenol component, a derivative having such an ester forming ability, a polyalkylene glycol component, and the like.

In addition, examples of the acid component which can be copolymerized include an aromatic carboxylic acid having a carbon number of 8 to 22 or more, a divalent or higher aliphatic carboxylic acid having 4 to 12 carbon atoms, and more preferably a divalent or higher valence. An alicyclic carboxylic acid having 8 to 15 carbon atoms and such a derivative having an ester forming ability. Specific examples of the above-mentioned copolymerizable acid component include terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, bis(p-carbodiphenyl)methane dicarboxylic acid, and 4-4'-di. Benzenecarboxylic acid, 1,2-bis(phenoxy)ethane-4,4'-dicarboxylic acid, sodium 5-sulfonate isophthalate, adipic acid, sebacic acid, sebacic acid, twelve Alkanoic acid, maleic acid, trimesic acid, trimellitic acid, pyromellitic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and ester forming ability a derivative. These may be used alone or in combination of two or more.

Further, examples of the copolymerizable alcohol component and/or the phenol component include a divalent or higher aliphatic alcohol having 2 to 15 carbon atoms, a divalent or higher aliphatic carbon number of 6 to 20 carbon atoms, and a carbon number of 6 ~40 of a divalent or higher aromatic alcohol, or a phenol and such a derivative having an ester forming ability. Specific examples of the copolymerizable alcohol component and/or phenol component include ethylene glycol, propylene glycol, butanediol, hexanediol, decanediol, neopentyl glycol, cyclohexanedimethanol, and cyclohexane. Alcohol, 2,2'-bis(4-hydroxyphenyl)propane, 2,2'-bis(4-hydroxycyclohexyl)propane, hydroquinone, glycerol, neopentyl alcohol, etc., and ester formation Such derivatives are such derivatives as cyclic esters such as ε-caprolactone.

Examples of the copolymerizable polyalkylene glycol component include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and random or block copolymers thereof, and alkylene glycols of bisphenol compounds. Modified polyoxyalkylene glycol, etc., such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like, such as random or block copolymers.

Among the polyester-based copolymer resins, a copolymer of a polyester resin material and a polyalkylene glycol component is preferred, more specifically a copolymer of a polyester resin and a polytetramethylene glycol, and further Specifically, a copolymer of polybutylene terephthalate resin and polytetramethylene glycol is preferred. Thereby, the release film 10 excellent in the viewpoint of plating adhesion can be obtained.

The content of the other copolymerizable component (particularly polytetramethylene glycol) is not particularly limited, and is preferably 5% by weight or more and 50% by weight or less based on the total amount of the polyester copolymer resin, and is preferably 10% by weight or more and 40% by weight. % below is especially good. When the content is at least the above lower limit value, the followability of the release film 10 to the object can be improved. Moreover, when the content is at most the above upper limit value, the mold release property can be further improved.

Further, the material for forming the release surface may contain an antioxidant, a slip agent, an anti-blocking agent, an antistatic agent, a coloring agent such as a dye and a pigment, and a stabilizer, in addition to the polyester resin material. An impact filler such as an additive, a fluororesin or a silicone rubber, or an inorganic filler such as titanium oxide, calcium carbonate or talc.

Further, in the release film 10 of the present embodiment, the intrinsic viscosity of the release layer 1 measured at 35 ° C according to ASTM D2857 is preferably 0.9 or more and 1.5 or less, more preferably 1.0 or more and 1.3 or less. Thereby, the release film 10 which can obtain the molded article of the favorable quality can be obtained.

Further, the conventional release film described in Patent Documents 1 to 3 and the like has an intrinsic viscosity of the release layer measured at 35 ° C according to ASTM D2857, which is different from the technical level of the release film 10 of the present embodiment. Moreover, when the polyester resin material contained in the conventional release film is used, it is not possible to sufficiently suppress the reaction and interaction of the unreacted functional group with a polar group (for example, a carboxyl group) in the material forming the surface of the object.

1 and 2 are cross-sectional views of the release film 10 of the present embodiment.

The release film 10 of the present embodiment may be formed into a single layer structure or may be formed into a multilayer structure. As shown in Fig. 1, when the release film 10 is formed into a single layer structure, the manufacturing steps of the release film 10 can be simplified. On the other hand, as shown in FIG. 2, when the layer structure of the mold release film 10 is a multilayer structure, the mold release property or the followability with respect to an object can be adjusted suitably.

Hereinafter, as the release film 10 of the present embodiment, a case where the multilayer structure shown in FIG. 2 is formed will be described as an example.

As shown in Fig. 2, in the release film 10 of the present embodiment, the release layer 1, the buffer layer 2, and the release layer 3 are laminated in this order. The layers are described in order below.

First, the release layer 1 is one that retains the release property from the surface of the molded article. Further, the pattern following function of the release layer 1 is followed by the shape of the object to which the release film 10 is placed. Further, the release layer 1 is a layer which forms a release surface, which is formed by a polyester resin material.

Moreover, as a method of forming the mold release layer 1, for example, a well-known method such as an air-cooling or water-cooling gas-filling method or a T-die extrusion method can be mentioned.

The thickness of the mold release layer 1 is not particularly limited, and is preferably 5 μm or more and 40 μm or less, and more preferably 7 μm or more and 20 μm or less. If the thickness of the release layer 1 is within the above range, the filling ability for the molded article can be improved.

Further, the modulus of elasticity of the release layer 1 at, for example, 180 ° C is not particularly limited, and is preferably 10 MPa or more and 200 MPa or less, and more preferably 30 MPa or more and 150 MPa or less. When the number of viscoelastic modulus of the release layer 1 is at least the above lower limit value, the release property of the release film 10 can be suppressed from being lowered. Moreover, when the viscoelastic modulus of the release layer 1 is at most the above upper limit value, the decrease in the filling ability of the release film 10 can be suppressed.

Further, the viscoelastic modulus of the release layer 1 can be evaluated, for example, by measuring the dynamic viscoelasticity measuring apparatus in a tensile mode at a frequency of 1 Hz and at a temperature elevation rate of 5 ° C/min from a normal temperature to 250 ° C.

Next, the buffer layer 2 is provided with a buffering function for embedding a surface gap of an object adjacent to the release layer 1 of the release film 10. Moreover, by forming the release film 10 having the buffer layer 2, the pressure applied to the entire object on which the release film 10 is placed can be made uniform during hot pressing. Further, when manufacturing a flexible circuit board, it is excellent in the degree of appearance completion (especially, generation of wrinkles).

Further, the buffer layer 2 is formed of a second resin different from the polyester resin material. at this time, The second resin may be a resin other than the polyester resin material or the polyester resin material having a composition different from the polyester resin material forming the release layer 1 . Among these, a resin other than the polyester resin material forming the release layer 1 is preferable.

Here, examples of the resin other than the polyester resin material forming the release layer 1 include an α-olefin polymer such as polyethylene or polypropylene; and ethylene, propylene, butene, pentene, hexene, and methyl pentane. An alpha olefin copolymer which is a copolymer component such as a olefin; an engineering plastic resin such as polyether oxime or polyphenylene sulfide; these may be used singly or in combination. Among these, an α-olefin copolymer is preferred. Specific examples thereof include a copolymer of an α-olefin such as ethylene and a (meth)acrylate, a copolymer of ethylene and vinyl acetate, a copolymer of ethylene and (meth)acrylic acid, and a part of the ionomers thereof. .

In particular, in the second resin, for example, a cured modulus of the second resin is preferably 10 MPa or less, and preferably 2 MPa or more and 8 MPa or less. When the elastic modulus of the cured product of the second resin is within the above range, the release film 10 having excellent cushioning function can be obtained particularly when a flexible circuit is produced.

Further, the elastic modulus can be evaluated, for example, by measuring with a dynamic viscoelasticity measuring apparatus in a stretching mode, a frequency of 1 Hz, and a temperature rising rate of 5 ° C/min from a normal temperature to 250 ° C.

Moreover, in order to further improve the cushioning property, the buffer layer 2 may contain a rubber component in addition to the second resin.

Examples of the rubber component include a styrene-based thermoplastic elastomer such as a styrene-butadiene copolymer or a styrene-isoprene copolymer, an olefin-based thermoplastic elastomer, a guanamine-based elastomer, and a polyester-based elastomer. Thermoplastic elastomer materials; rubber materials such as natural rubber, isoprene rubber, chloroprene rubber, and silicone rubber.

In addition, the content of the rubber component in the buffer layer 2 is not particularly limited, and is preferably 5 parts by weight or more and 50 parts by weight or less based on 100 parts by weight of the second resin, and more preferably 10 parts by weight or more and 40 parts by weight or less. It is better. If the content of the rubber component in the buffer layer 2 is within the above range, A release film 10 having more excellent cushioning properties can be obtained.

Further, the buffer layer 2 may contain an antioxidant, a slip agent, an anti-blocking agent, an antistatic agent, a coloring agent such as a dye or a pigment, an additive such as a stabilizer, a fluororesin, a silicone rubber, or the like in addition to the second resin. An inorganic filler such as an impact imparting agent, titanium oxide, calcium carbonate or talc.

Further, as a method of forming the buffer layer 2, for example, a well-known method such as an air-cooling or water-cooling gas-filling method or a T-die extrusion method can be mentioned.

Further, the thickness of the buffer layer 2 is not particularly limited, and is preferably 30 μm or more and 100 μm or less, and more preferably 50 μm or more and 70 μm or less. When the thickness of the buffer layer 2 is at least the above lower limit value, the cushioning property of the release film 10 can be suppressed from being lowered. When the thickness of the buffer layer 2 is at most the above upper limit value, the decrease in mold release property can be suppressed.

Further, the softening temperature of the buffer layer 2 is not particularly limited, and is preferably 80° C. or higher and 150° C. or lower, and particularly preferably 90° C. or higher and 140° C. or lower. When the softening temperature of the buffer layer 2 is within the above range, the release film 10 having more excellent cushioning properties can be obtained.

The release layer 3 maintains the releasability of the reinforcing sheet used in molding at the time of hot pressing or the like.

The release layer 3 is composed of a third resin having a softening point higher than that of the second resin. Thereby, the release property of the reinforcing plate can be further improved.

Examples of the third resin include 4-methyl-1-pentene resin, 4-methyl-1-pentene, and other α-olefins such as ethylene, propylene, 1-butene, and 1-hexene. a copolymer of a carbon number of 2 to 20 such as octene, 1-decene, 1-tetradecene or 1-octadecene, or an olefin-based resin such as polypropylene, and the same polymerization as that used for the release layer 1. Ester resin or the like.

Further, the third resin may be the same as or different from the polyester resin material forming the release layer 1, and the same is preferable. Thereby, the release film 10 can be used without any distinction, so that misuse of the inside of the release film 10 can be avoided.

Further, the softening point of the third resin is not particularly limited, and is preferably 100 ° C or more, more preferably 120 ° C or more. Thereby, in addition to the mold release property, the volatilization component of the third resin or the third resin adheres to the reinforcing plate made of a SUS plate or the like can be reduced.

Further, the release layer 3 may contain, in addition to the third resin, an antioxidant, a slip agent, an anti-blocking agent, an antistatic agent, a coloring agent such as a dye or a pigment, an additive such as a stabilizer, a fluororesin, a silicone rubber, or the like. An impact filler, an inorganic filler such as titanium oxide, calcium carbonate or talc.

Further, as a method of forming the release layer 3, for example, a well-known method such as an air-cooling or water-cooling aeration extrusion method or a T-die extrusion method can be mentioned.

Further, the thickness of the release layer 3 is not particularly limited, and is preferably 5 μm or more and 60 μm or less. When the thickness of the mold release layer 3 is at least the above lower limit value, the entire release film 10 becomes a rigid material during hot pressing, and the mold release property is improved. Moreover, when the thickness of the mold release layer 3 is less than or equal to the above upper limit value, the film formability of the release film 10 is suitable.

The release film 10 of the present embodiment is preferably formed by a three-layer structure in which the release layer 1 / the buffer layer 2 / the release layer 3 are formed.

Further, the release film 10 of the present embodiment has three layers of the release layer 1, the buffer layer 2, and the release layer 3, but the present invention is not limited thereto, and may have an adhesive layer or a resist. Four or more layers, such as a gas layer, and the like, are composed of four or more layers.

Further, the release film 10 of the present embodiment is not particularly limited, and may be disposed inside a mold composed of an upper mold and a lower mold, or may be disposed on a cover film or a copper clad laminate. Among these, in the case of being disposed on the cover film or on the copper clad laminate, the release property of the release film 10 of the present embodiment can be sufficiently exhibited.

Examples of the object of the embodiment include a cover film or a copper-clad laminate. The object is made of a material containing at least a thermosetting resin whose surface is semi-hardened before hot pressing. Former. Moreover, as a thermosetting resin, an epoxy resin etc. are mentioned, for example.

<Method of Manufacturing Release Film>

The release film 10 of the present embodiment can be obtained by separately producing the release layer 1, the buffer layer 2, and the release layer 3, and then joining them by a laminator or the like to obtain a release film 10, thereby releasing the release film 10. The layer 1, the buffer layer 2, and the release layer 3 are preferably formed by a method such as air-cooling or water-cooling co-extrusion aeration or co-extrusion T-die to form a release film 10. Among them, from the viewpoint of excellent control of the thickness of each layer, a method of forming a film by a co-extrusion T-die method is particularly preferable.

Further, the release layer 1, the buffer layer 2, and the release layer 3 may be directly joined or joined together via an adhesive layer.

Conventionally, a release film has been produced by using, for example, a polyester resin obtained by performing a polycondensation reaction in a molten state. The use of the polyester resin material obtained by polycondensation to produce a release film as such is also carried out in the prior art.

On the other hand, in the release film 10 of the present embodiment, the release layer 1 and/or the release layer 3 which form the release surface are not using the polyester resin material obtained by the conventional polycondensation reaction, but using, for example, a solid phase. It is produced by polymerizing the obtained polyester resin material.

In the release film 10 of the present embodiment, in order to control the amount of the terminal carboxylic acid measured by the indicator titration method using the release layer 1 to less than 40, the type of the polymerization catalyst used for controlling the solid phase polymerization reaction is The reaction conditions such as the reaction temperature and the reaction time can be obtained. In order to prevent the functional group of the material for forming the release surface of the release film 10 during hot pressing from reacting with the material forming the surface of the object on which the release film 10 is disposed, and interacting with each other, the release film 10 of the present embodiment is obtained. Controlling these factors is especially important for molded products of good quality.

<How to use the release film>

Next, a method of using the release film 10 of the present embodiment will be described.

First, the release film 10 of the present embodiment described above is placed on the surface of an object formed of a material containing a thermosetting resin in a semi-hardened state. Then, the object on which the release film 10 is placed is hot-pressed in the mold. Thereby, unreacted functionalities in the release film 10 can be suppressed. The base reacts with and interacts with a polar group (for example, a carboxyl group) in the material forming the surface of the object. Thereby, it is possible to suppress the adhesion of a very small amount of foreign matter or a part of the release film 10 to the surface of the molded article after peeling off the release film 10 from the molded body obtained by hot pressing, thereby preventing the surface of the molded article from being rough, thereby suppressing formation at the time of hot pressing. The functional group of the material of the release surface of the release film 10 reacts with and interacts with the material forming the surface of the object on which the release film 10 is disposed, thereby obtaining a molded article having good quality.

The embodiments of the present invention have been described above, but other embodiments than the above may be employed as exemplified by the present invention.

[Examples]

Hereinafter, the present invention will be described by way of examples and comparative examples, but the invention is not limited thereto. Further, in the present embodiment, a release film 10 composed of a three-layer structure shown in Fig. 2 will be described as an example.

<Manufacture of release film> (Example 1)

1. Manufacture of polyester resin materials

The content of 2-(4'-hydroxybutoxy)tetrahydrofuran (hereinafter referred to as "HTHF") was 0.44% by weight based on 1,4-butanediol (hereinafter referred to as "BG"). The content was subjected to an esterification reaction with respect to terephthalic acid (hereinafter referred to as "TPA") of 0.14% by weight of TPA 1132 g (BG/TPA molar ratio of 1.8), followed by a polycondensation reaction.

First, a total amount of TPA, BG 750 g, 0.8 g of tetrabutyl titanate, and 0.7 g of monobutyl hydroxytin oxide were placed in a reactor equipped with a rectification column, and after starting the esterification reaction at 190 ° C and 400 mmHg, The residual BG was continuously added while slowly heating up.

0.08 g of tetrabutyl titanate and 0.01 g of phosphoric acid were added to the reactant, and a polycondensation reaction was carried out at 250 ° C and 0.5 mmHg.

The fine particles of the produced polymer were placed in a rotary reaction vessel, and subjected to solid phase polymerization at 190 ° C under a reduced pressure of 0.5 mmHg for 8 hours to obtain a high polymerization degree polybutylene terephthalate (hereinafter referred to as PBT). ).

2. Manufacture of release film

A buffer layer 2 comprising a release layer composed of PBT manufactured by the above method, a polypropylene layer, a modified polyethylene, and a PBT manufactured by the above method is produced by hot pressing. A three-layer release film of the release layer 3 composed of PBT produced by the above method. The amount of terminal carboxylic acid (AV value) of the PBT of the release layer 1 and the release layer 3 was 24.0.

Further, the buffer layer 2 is formed using the following materials.

Polypropylene: Sumitomo Chemical Co., Ltd., FH1016

Modified polyethylene: ethylene-methyl methacrylate copolymer (made by Sumitomo Chemical Co., Ltd., WD106) and acid-modified polyethylene (Mitsubishi Chemical Co., Ltd., F515A)

PBT: The same as the PBT used for the release layer.

Then, mixing was carried out in such a manner that the blending ratio became a ratio of polypropylene:ethylene-methyl methacrylate copolymer: acid-modified polyethylene: PBT = 15:30:40:15. Further, the thickness of each layer of the obtained release film was 1:30 μm for the release layer, 60 μm for the buffer layer 2, and 30 μm for the release layer.

(Example 2)

A release film was produced and evaluated in the same manner as in Example 1 except that the reaction conditions related to the solid phase polymerization reaction were changed so that the AV value of the PBT of the release layer 1 and the release layer 3 was 18.7.

(Example 3)

A release film was produced and evaluated in the same manner as in Example 1 except that the reaction conditions related to the solid phase polymerization reaction were changed so that the AV value of the PBT of the release layer 1 and the release layer 3 was 14.3.

(Example 4)

A release film was produced and evaluated in the same manner as in Example 1 except that the reaction conditions related to the solid phase polymerization reaction were changed so that the AV value of the PBT of the release layer 1 and the release layer 3 was 28.1.

(Comparative Example 1)

A release film was produced and evaluated in the same manner as in Example 1 except that PBT (manufactured by Toray Industries, Inc., TORAYCON product number: 1100 M) having an AV value of 45.0 was used for the release layer 1 and the release layer 3.

The measurement methods and evaluation methods performed in the above Examples 1 to 4 and Comparative Example 1 will be described in detail below.

<evaluation item>

The amount of terminal carboxylic acid (AV value): determined by indicator titration. Specifically, the sample adjusted by the following method was used and calculated from the following formula (A).

(1) Measurement of the preparation of samples

First, about 2 g of the obtained release layer 1 was weighed into a 100 mL bottle. Next, 50 mL of o-cresol was injected into the bottle. Then, a stir bar was placed in the bottle, and the mixture was heated and stirred at 100 ± 5 ° C for about 30 minutes until the release layer was completely dissolved. After the release layer was melted, it was placed until the temperature of the solution in the bottle became 30 °C. Next, 3 mL of a 0.01 mol/L potassium chloride solution was added, and the mixture was titrated with a 0.05 mol/L ethanolic potassium hydroxide solution.

(2) Evaluation of standard samples

First, 50 mL of o-cresol was weighed into a 100 mL flask. Next, a stir bar was placed in the 100 mL flask, and 3 mL of a 0.01 mol/L potassium chloride solution was added. The titration of the standard sample was carried out using the same electrode as that used for the measurement of the sample.

(3) Calculation of AV value

It is calculated by the following formula (A). In addition, the calculation results are expressed in meq COOH/kg.

Formula (A): The amount of terminal carboxylic acid = {(the amount of KOH dropped in the measurement sample [mL] - the amount of KOH dropped on the standard sample [mL]) × the specified number of KOH × 1000} / the weight of the measured sample [ g]

Intrinsic viscosity (IV value): determined at 35 ° C according to ASTM D2857. Specifically, the sample adjusted by the following method was used and calculated from the following formula (B).

(1) Measurement of the preparation of samples

First, about 3~5g of the obtained release layer is put into a 100mL beaker, and then injected into the beaker. ketone. Thereafter, the sample in the beaker was dried at 105 ° C for 30 minutes using an oven. Next, in a 100 mL bottle, 0.45 to 0.5 g of the dried polymer was measured in an accuracy of 4 points below the decimal point. Next, the weight of the release layer per unit volume was diluted 100 times using an automatic measuring device so that the accuracy was ±0.01 mL. Thereafter, the release layer was transferred to the bottle, and the bottle was sealed with a gasket. Next, the bottle was heated at 110 ° C for about 60 to 75 minutes while stirring until the release layer was completely melted. Then, the obtained bottle was taken out from the constant temperature bath and placed in a cooling bath.

(2) Determination

First, 18 mL of the solvent measured using the measuring flask was injected into the tubular member of the viscometer to wash the inside of the tubular member. Then, after setting the tubular member of the viscometer to 35 ° C + 0.1 ° C for 10 minutes, the polymer solution was injected into the viscometer three times. Next, the inside of the viscometer was vacuumed by a pump, and the solution was sucked in the container disposed in the upper portion of the tubular member. Thereafter, the vacuum state in the viscometer was released, and the time between the passage of the solvent in the tubular member was measured by a timer. This measurement was performed four times, and the average value was calculated. In addition, an automatic viscometer (SCHOTT AVS-500) was used in this measurement.

(3) Calculation of IV value

An o-chlorophenol having a phenol/tetrachloroethane ratio of 3:2 at 35 ° C at 30 ° C was used as a standard sample. The IV value in the present embodiment is calculated by the following formula (B).

Formula (B): IV value = {(measurement flow time of sample / circulation time of standard sample) - 1} × 0.7789 + 0.111

Mold release property: The adhesive surface of CL (CM type) manufactured by Zesho Co., Ltd. was bonded to the release surface of the release film, and hot pressed at 195 ° C × 2 min × 6 MPa, and a tensile tester (manufactured by A&D Co., Ltd.) was used. Force gauge AD-4932A-50N), the peeling force between the release surface and the CL adhesive was measured at a speed of about 1000 mm/min in the 180° direction. The measurement was performed immediately after the pressing, and the mold release property was evaluated based on the following criteria.

○: peelable

×: not easily peeled off and film or CL cracked

Followability (finished appearance wrinkles): Measured according to the "7.5.7.2 wrinkles" of the JPCA specification.

○: wrinkle generation rate is less than 2.0%

×: wrinkle generation rate is 2.0% or more

The amount of exudation of the CL adhesive: for the presence or absence of the adhesive layer of the CL on the circuit board, the evaluation of the bleed out toward the terminal portion of the circuit according to "JPCA specification 7.5.3.6, Adhesive flow of the cover layer and bleed of the top coat" the amount. The amount of exudation is less than 150 μm .

○: The amount of exudation is less than 150 μ m

×: The amount of exudation is 150 μm or more

Formability: Formability was evaluated visually in accordance with "JPCA Standard 7.5.3.3 Bubbles". Each symbol is as follows. The number of evaluation samples was evaluated as n=100, and it was confirmed that the number of voids on the sample surface was less than 2% of the number of evaluation samples.

○: void incidence is less than 2.0%

×: The void occurrence rate is 2.0% or more

The evaluation results regarding the above evaluation items are shown in Table 1 below.

The release film of the embodiment can suppress the reaction of the functional group of the material forming the release surface of the release film during hot pressing with the material forming the surface of the object on which the release film is disposed, compared to the release film of the comparative example. Interactions give molded products of good quality.

(Second embodiment)

Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and the description is omitted as appropriate.

<release film>

The release film 30 of the present embodiment has a release film 30 comprising a release layer 21 of a polyester resin material, and the intrinsic viscosity of the release layer 21 measured at 35 ° C according to ASTM D2857 is 0.9 or more and 1.5. The following polyester resin materials. Thereby, the release film 30 can be obtained, which can suppress the reaction and interaction of the functional groups of the material forming the release surface of the release film 30 during hot pressing with the material forming the surface of the object on which the release film 30 is disposed, thereby obtaining A molded product of good quality.

In the release film 30 of the present embodiment, the release layer 21 is a resin which forms a surface of the object to be contacted (hereinafter also referred to as a "release surface") when at least the release film 30 is placed on the object. The polyester resin is a polycondensate of a polyvalent carboxylic acid (dicarboxylic acid) and a polyhydric alcohol (diol), and is a compound having a plurality of carboxyl groups (-COOH).

Further, the surface of the object before the release film is disposed is usually formed of a material containing a thermosetting resin in a semi-hardened state. The release film 30 of the present embodiment is used by being disposed on the surface of an object formed of a material containing the thermosetting resin in the semi-hardened state. Moreover, the molded article can be obtained by hot pressing in a state in which the release film 30 is placed on the surface of the object.

When a conventional release film is used, it is presumed that the following phenomenon occurs.

It is considered that in the conventional hot pressing, the carboxyl group in the material forming the release surface in the release film reacts with and interacts with the unreacted functional groups of the cover film adhesive. Such an unreacted functional group is not particularly limited, and examples thereof include an epoxy group which is a functional group which is easy to interact with.

Hereinafter, a case where the unreacted functional group is an epoxy group will be described as an example.

When the conventional release film described in Patent Documents 1 to 3 and the like is used, the reason why a part of the release film remains as a contaminant in the cover film is not clear, and it is considered to be a pole of a carboxyl group. The base is related to the contamination of the molded article.

Further, the conventional mold release films described in Patent Documents 1 to 3 and the like have an intrinsic viscosity of the release layer 21 measured at 35 ° C according to ASTM D2857, which is different from the technical level of the release film 30 of the present embodiment. As described above, when the polyester resin material contained in the conventional release film is used, it is not possible to sufficiently prevent the unreacted functional group from reacting with and interacting with a polar group (for example, a carboxyl group) in the material forming the surface of the object.

On the other hand, according to the release film 30 of the present embodiment, the intrinsic viscosity of the release layer 21 measured at 35 ° C according to ASTM D2857 satisfies the above specific conditions, so that it is possible to suppress a slight amount of foreign matter or a part of the release film 30 from adhering. The surface of the molded article after the release film 30 is peeled off from the molded body obtained by hot pressing, and a mold release property excellent in height to prevent the surface of the molded article from being roughened is obtained. It is considered that this is because a polyester resin material exhibiting a value of 0.9 or more and 1.5 or less by using the intrinsic viscosity of the release layer 21 measured at 35 ° C according to ASTM D2857 is used as a material for forming a release surface, and is present in the molding. The amount of carboxyl groups reacting and interacting with unreacted functional groups on the surface of the product is reduced compared to the prior art. Therefore, the release film 30 of the present embodiment can obtain a highly releasable property as compared with the conventional release film.

Further, the roughness generated on the surface of the molded article after hot pressing means that one part of the surface of the molded article has undulations, one part of the surface of the molded article is festered, the shape of the surface of the molded article is not smooth, and the state is rough.

Further, in the release film 30 of the present embodiment, the intrinsic viscosity of the release layer 21 measured at 35 ° C according to ASTM D2857 may be 0.9 or more and 1.5 or less, and more preferably 1.0 or more and 1.3 or less. Thereby, the functional group of the material forming the release surface of the release film 30 at the time of hot pressing can be prevented from reacting with and interacting with the material forming the surface of the object on which the release film 30 is disposed, and a molded article having good quality can be obtained.

Further, the polyester resin material in the present embodiment is not particularly limited, and examples thereof include polyethylene terephthalate resin, polybutylene terephthalate resin, and polytrimethylene terephthalate resin. A polyalkylene terephthalate resin such as a polybutylene terephthalate resin. Among these, it is preferred to use a polybutylene terephthalate resin. Thereby, the functional group of the material which is hot-pressed to form the release surface of the release film 30 can be inhibited from reacting with and interacting with the material forming the surface of the object on which the release film 30 is disposed, thereby obtaining a molded article having good quality.

Further, the polyester resin material may be a polyester-based copolymer resin in which other components are copolymerized as needed. Examples of the copolymerization component include a well-known acid component, an alcohol component, a phenol component, a derivative having such an ester forming ability, a polyalkylene glycol component, and the like.

In addition, examples of the acid component which can be copolymerized include an aromatic carboxylic acid having a carbon number of 8 to 22 or more, a divalent or higher aliphatic carboxylic acid having 4 to 12 carbon atoms, and more preferably a divalent or higher valence. An alicyclic carboxylic acid having 8 to 15 carbon atoms and such a derivative having an ester forming ability. Specific examples of the above-mentioned copolymerizable acid component include terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, bis(p-carbodiphenyl)methane dicarboxylic acid, and 4-4'-di. Benzenecarboxylic acid, 1,2-bis(phenoxy)ethane-4,4'-dicarboxylic acid, sodium 5-sulfonate isophthalic acid, adipic acid, sebacic acid, sebacic acid, twelve Alkanoic acid, maleic acid, trimesic acid, trimellitic acid, pyromellitic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and ester forming ability a derivative. These may be used alone or in combination of two or more.

Further, examples of the copolymerizable alcohol component and/or the phenol component include a divalent or higher aliphatic alcohol having 2 to 15 carbon atoms, a divalent or higher aliphatic carbon number of 6 to 20 carbon atoms, and a carbon number of 6 ~40 of a divalent or higher aromatic alcohol, or a phenol and such a derivative having an ester forming ability. Specific examples of the copolymerizable alcohol component and/or phenol component include ethylene glycol, propylene glycol, butanediol, hexanediol, decanediol, neopentyl glycol, cyclohexanedimethanol, and cyclohexane. Alcohol, 2,2'-bis(4-hydroxyphenyl)propane, 2,2'-bis(4-hydroxycyclohexyl)propane, hydroquinone, glycerol, neopentyl alcohol, etc., and ester formation Such derivatives are such derivatives as cyclic esters such as ε-caprolactone.

Examples of the copolymerizable polyalkylene glycol component include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and random or block copolymers thereof, and alkylene glycols of bisphenol compounds. Modified polyoxyalkylene glycol, etc., such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like, such as random or block copolymers.

Among the polyester-based copolymer resins, a copolymer of a polyester resin material and a polyalkylene glycol component is preferred, more specifically a copolymer of a polyester resin and a polytetramethylene glycol, and further Specifically, a copolymer of polybutylene terephthalate resin and polytetramethylene glycol is preferred. Thereby, the release film 30 excellent in the viewpoint of plating adhesion can be obtained.

The content of the other copolymerizable component (particularly polytetramethylene glycol) is not particularly limited, and is preferably 5% by weight or more and 50% by weight or less based on the total amount of the polyester copolymer resin, and is preferably 10% by weight or more and 40% by weight. % below is especially good. When the content is at least the above lower limit value, the followability of the release film 30 to the object can be improved. Moreover, when the content is at most the above upper limit value, the mold release property can be further improved.

Further, the material for forming the release surface may contain, in addition to the polyester resin material, an antioxidant, a slip agent, an anti-blocking agent, an antistatic agent, a coloring agent such as a dye or a pigment, an additive such as a stabilizer, a fluororesin, or the like. An impact-imparting agent such as a silicone rubber, or an inorganic filler such as titanium oxide, calcium carbonate or talc.

Further, the amount of the terminal carboxylic acid measured by the indicator titration method using the release layer 21 of the release film 30 of the present embodiment is preferably less than 40, more preferably 25 or less. Thereby, the functional group of the material forming the release surface of the release film 30 at the time of hot pressing can be prevented from reacting with and interacting with the material forming the surface of the object on which the release film 30 is disposed, and a molded article having good quality can be obtained.

In addition, the amount of the terminal carboxylic acid measured by the indicator titration method using the release layer of the conventional release film described in Patent Documents 1 to 3 and the like is different from the technical level of the release film 30 of the present embodiment. As described above, when the polyester resin material contained in the conventional release film is used, it is not possible to sufficiently prevent the unreacted functional group from reacting with and interacting with a polar group (for example, a carboxyl group) in the material forming the surface of the object.

3 and 4 are cross-sectional views of the release film 30 of the present embodiment.

The release film 30 of the present embodiment may be a single layer structure or a multilayer structure. By. As shown in FIG. 3, when the release film 30 is formed into a single layer structure, the manufacturing steps of the release film 30 can be simplified. On the other hand, as shown in FIG. 4, when the layer structure of the mold release film 30 is a multilayer structure, the mold release property or the followability with respect to an object can be adjusted suitably.

Hereinafter, as the release film 30 of the present embodiment, a case where the multilayer structure shown in FIG. 4 is formed will be described as an example.

As shown in Fig. 4, the release film 30 of the present embodiment is a layer in which the release layer 21, the buffer layer 22, and the release layer 23 are laminated in this order. The layers are described in order below.

First, the release layer 21 is kept from the surface of the molded article. Further, the pattern followability function of the release layer 21 is followed by the shape of the object to which the release film 30 is placed. Further, the release layer 21 is a layer which forms a release surface which is formed of a polyester resin material.

Further, as a method of forming the release layer 21, for example, a well-known method such as an air-cooling or water-cooling gas-filling method or a T-die extrusion method can be mentioned.

The thickness of the mold release layer 21 is not particularly limited, and is preferably 5 μm or more and 40 μm or less, and more preferably 7 μm or more and 20 μm or less. If the thickness of the release layer 21 is within the above range, the filling ability for the molded article can be improved.

Further, the modulus of elasticity of the mold release layer 21, for example, at 180 ° C is not particularly limited, and is preferably 10 MPa or more and 200 MPa or less, and more preferably 30 MPa or more and 150 MPa or less. When the modulus of elasticity of the release layer 21 is at least the above lower limit value, the release property of the release film 30 can be suppressed from being lowered. Moreover, when the number of viscoelastic modulus of the release layer 21 is at most the above upper limit value, the decrease in the filling ability of the release film 30 can be suppressed.

Further, the viscoelastic modulus of the release layer 21 can be evaluated, for example, by a dynamic viscoelasticity measuring apparatus in a tensile mode at a frequency of 1 Hz and at a temperature elevation rate of 5 ° C/min from a normal temperature to 250 ° C.

Next, the buffer layer 22 is provided with a pair for burying adjacent to the release layer 21 of the release film 30. The buffer function of the surface gap of the object. Moreover, by forming the release film 30 having the buffer layer 22, the pressure applied to the entire object on which the release film 30 is disposed can be made uniform during hot pressing. Further, when manufacturing a flexible circuit board, it is excellent in the degree of appearance completion (especially, generation of wrinkles).

Further, the buffer layer 22 is formed of a second resin different from the polyester resin material. In this case, the second resin may be a resin other than the polyester resin material or the polyester resin material having a composition different from the polyester resin material forming the release layer 21 . Among these, a resin other than the polyester resin material forming the release layer 21 is preferable.

Here, examples of the resin other than the polyester resin material forming the release layer 21 include an α-olefin polymer such as polyethylene or polypropylene; and ethylene, propylene, butene, pentene, hexene, and methyl pentane. An alpha olefin copolymer which is a copolymer component such as a olefin; an engineering plastic resin such as polyether oxime or polyphenylene sulfide; these may be used singly or in combination. Among these, an α-olefin copolymer is preferred. Specific examples thereof include a copolymer of an α-olefin such as ethylene and a (meth)acrylate, a copolymer of ethylene and vinyl acetate, a copolymer of ethylene and (meth)acrylic acid, and a part of the ionomers thereof. .

In particular, in the second resin, for example, a cured modulus of the second resin is preferably 10 MPa or less, and preferably 2 MPa or more and 8 MPa or less. When the elastic modulus of the cured product of the second resin is within the above range, the release film 30 having excellent cushioning function can be obtained particularly when a flexible circuit is manufactured.

Further, the elastic modulus can be evaluated, for example, by measuring with a dynamic viscoelasticity measuring apparatus in a stretching mode, a frequency of 1 Hz, and a temperature rising rate of 5 ° C/min from a normal temperature to 250 ° C.

Moreover, in order to further improve the cushioning property, the buffer layer 22 may contain a rubber component in addition to the second resin.

Examples of the rubber component include a styrene-based thermoplastic elastomer such as a styrene-butadiene copolymer or a styrene-isoprene copolymer, an olefin-based thermoplastic elastomer, a guanamine-based elastomer, and a poly A thermoplastic elastomer material such as an ester elastomer; a rubber material such as natural rubber, isoprene rubber, chloroprene rubber or silicone rubber.

In addition, the content of the rubber component in the buffer layer 22 is not particularly limited, and is preferably 5 parts by weight or more and 50 parts by weight or less based on 100 parts by weight of the second resin, and more preferably 10 parts by weight or more and 40 parts by weight or less. It is better. When the content of the rubber component in the buffer layer 22 is within the above range, the release film 30 having more excellent cushioning properties can be obtained.

Further, the buffer layer 22 may contain an antioxidant, a slip agent, an anti-blocking agent, an antistatic agent, a coloring agent such as a dye or a pigment, an additive such as a stabilizer, a fluororesin, a silicone rubber, or the like in addition to the second resin. An inorganic filler such as an impact imparting agent, titanium oxide, calcium carbonate or talc.

Further, as a method of forming the buffer layer 22, for example, a well-known method such as an air-cooling or water-cooling gas-filling method or a T-die extrusion method can be mentioned.

Further, the thickness of the buffer layer 22 is not particularly limited, and is preferably 30 μm or more and 100 μm or less, and more preferably 50 μm or more and 70 μm or less. When the thickness of the buffer layer 22 is at least the above lower limit value, the cushioning property of the release film 30 can be suppressed from being lowered. When the thickness of the buffer layer 22 is at most the above upper limit value, the decrease in mold release property can be suppressed.

Further, the softening temperature of the buffer layer 22 is not particularly limited, and is preferably 80° C. or higher and 150° C. or lower, and particularly preferably 90° C. or higher and 140° C. or lower. When the softening temperature of the buffer layer 22 is within the above range, the release film 30 having more excellent cushioning properties can be obtained.

The release layer 23 maintains the releasability of the reinforcing sheet used in molding at the time of hot pressing or the like.

The release layer 23 is composed of a third resin having a softening point higher than that of the second resin. Thereby, the release property of the reinforcing plate can be further improved.

Examples of the third resin include 4-methyl-1-pentene resin, 4-methyl-1-pentene, and other α-olefins such as ethylene, propylene, 1-butene, and 1-hexene. -octene, 1-decene, 1-tetradecene, A copolymer of an α-olefin having 2 to 20 carbon atoms such as 1-octadecene, an olefin resin such as polypropylene, and a polyester resin similar to those used for the release layer 21.

Further, the third resin may be the same as or different from the polyester resin material forming the release layer 21, and the same is preferable. Thereby, the release film 30 can be used without any difference in the surface, so that misuse of the inside of the release film 30 can be avoided.

Further, the softening point of the third resin is not particularly limited, and is preferably 100 ° C or more, more preferably 120 ° C or more. Thereby, in addition to the mold release property, the volatilization component of the third resin or the third resin adheres to the reinforcing plate made of a SUS plate or the like can be reduced.

Further, the mold release layer 23 may contain an antioxidant, a slip agent, an anti-blocking agent, an antistatic agent, a coloring agent such as a dye or a pigment, an additive such as a stabilizer, a fluororesin, a silicone rubber, etc., in addition to the third resin. An impact filler, an inorganic filler such as titanium oxide, calcium carbonate or talc.

Further, as a method of forming the release layer 23, for example, a well-known method such as an air-cooling or water-cooling gas-filling method or a T-die extrusion method can be mentioned.

Further, the thickness of the release layer 23 is not particularly limited, and is preferably 5 μm or more and 60 μm or less. When the thickness of the mold release layer 23 is at least the above lower limit value, the entire release film 30 becomes a rigid material during hot pressing, and the mold release property is improved. Moreover, when the thickness of the mold release layer 23 is less than or equal to the above upper limit value, the film formability of the release film 30 is suitable.

The release film 30 of the present embodiment is preferably formed by a three-layer structure in which the release layer 21, the buffer layer 22, and the release layer 23 are formed.

Further, the release film 30 of the present embodiment has three layers of the release layer 21, the buffer layer 22, and the release layer 23, but the present invention is not limited thereto, and may have an adhesive layer or a resist. Four or more layers, such as a gas layer, and the like, are composed of four or more layers.

Further, the release film 30 of the present embodiment is not particularly limited, and may be disposed inside a mold composed of an upper mold and a lower mold, or may be disposed on a cover film or a copper clad laminate. Among these, in the case of being disposed on the cover film or on the copper clad laminate, the release property of the release film 30 of the present embodiment can be sufficiently exhibited.

Examples of the object of the embodiment include a cover film or a copper-clad laminate. The object is formed by a material containing at least a thermosetting resin whose surface is semi-hardened before hot pressing. Moreover, as a thermosetting resin, an epoxy resin etc. are mentioned, for example.

<Method of Manufacturing Release Film>

In the release film 30 of the present embodiment, the release layer 21, the buffer layer 22, and the release layer 23, respectively, are joined by a laminator or the like to obtain a release film 30, and the release layer 21 is obtained. The buffer layer 22 and the release layer 23 are preferably formed by a method such as air-cooling or water-cooling co-extrusion aeration or co-extrusion T-die to form a release film 30. Among them, from the viewpoint of excellent control of the thickness of each layer, a method of forming a film by a co-extrusion T-die method is particularly preferable.

Further, the release layer 21, the buffer layer 22, and the release layer 23 may be directly bonded to each other or may be joined via an adhesive layer.

Conventionally, a release film has been produced by using, for example, a polyester resin obtained by performing a polycondensation reaction in a molten state. The use of the polyester resin material obtained by polycondensation to produce a release film as such is also carried out in the prior art.

On the other hand, in the release film 30 of the present embodiment, the release layer 21 and/or the release layer 23 which form the release surface are not using the polyester resin material obtained by the conventional polycondensation reaction, but using, for example, a solid phase. It is produced by polymerizing the obtained polyester resin material.

The release film 30 of the present embodiment is used to control the type of the polymerization catalyst used for the solid phase polymerization by controlling the intrinsic viscosity of the release layer 21 measured at 35 ° C according to ASTM D2857 to 0.9 or more and 1.5 or less. The reaction conditions such as the reaction temperature and the reaction time can be obtained. The functional group of the material for forming the release surface of the release film 30 at the time of suppressing hot pressing reacts with and reacts with the material forming the surface of the object on which the release film 30 is disposed, in order to obtain the release film 30 of the present embodiment. Controlling these factors is especially important for molded products of good quality.

<How to use the release film>

Next, a method of using the release film 30 of the present embodiment will be described.

First, the release film 30 of the present embodiment described above is placed on the surface of an object formed of a material containing a thermosetting resin in a semi-hardened state. Then, the object on which the release film 30 is placed is hot-pressed in the mold. Thereby, it is possible to suppress the interaction between the unreacted functional groups in the release film 30 and the polar groups (for example, carboxyl groups) in the material forming the surface of the object. Thereby, it is possible to suppress the adhesion of a very small amount of foreign matter or a part of the release film 30 to the surface of the molded article after peeling off the release film 30 from the molded body obtained by hot pressing, thereby preventing the surface of the molded article from being rough, thereby suppressing formation at the time of hot pressing. The functional group of the material of the release surface of the release film 30 reacts with and interacts with the material forming the surface of the object on which the release film 30 is disposed, thereby obtaining a molded article having good quality.

The embodiments of the present invention have been described above, but other embodiments than the above may be employed as exemplified by the present invention.

[Examples]

Hereinafter, the present invention will be described by way of examples and comparative examples, but the invention is not limited thereto. Further, in the present embodiment, a release film 30 composed of a three-layer structure shown in Fig. 4 below will be described as an example.

<Manufacture of release film> (Example 5)

1. Manufacture of polyester resin materials

The content of 2-(4'-hydroxybutoxy)tetrahydrofuran (hereinafter referred to as "HTHF") was 0.44% by weight based on 1,4-butanediol (hereinafter referred to as "BG"). The content was subjected to an esterification reaction with respect to terephthalic acid (hereinafter referred to as "TPA") of 0.14% by weight of TPA 1132 g (BG/TPA molar ratio of 1.8), followed by a polycondensation reaction.

First, the total amount of TPA, BG 750g, 0.8 g of tetrabutyl titanate, and 0.7 g of monobutyl hydroxytin oxide were put into a reactor equipped with a rectification column, and the esterification reaction was started at 190 ° C and 400 mmHg. After that, the residual BG was continuously added while slowly heating up.

0.08 g of tetrabutyl titanate and 0.01 g of phosphoric acid were added to the reactant, and a polycondensation reaction was carried out at 250 ° C and 0.5 mmHg.

The fine particles of the produced polymer were placed in a rotary reaction vessel, and subjected to solid phase polymerization at 190 ° C under a reduced pressure of 0.5 mmHg for 8 hours to obtain a high polymerization degree polybutylene terephthalate (hereinafter referred to as PBT). ).

2. Manufacture of release film

A buffer layer 22 comprising a release layer 21 composed of PBT manufactured by the above method, a polypropylene layer, a modified polyethylene, and a PBT manufactured by the above method is produced by hot pressing, and A three-layer release film of the release layer 23 composed of PBT manufactured by the above method. The intrinsic viscosity (IV value) of the PBT of the release layer 21 and the release layer 23 was 1.22.

Further, the buffer layer 22 is formed using the following materials.

Polypropylene: Sumitomo Chemical Co., Ltd., FH1016

Modified polyethylene: ethylene-methyl methacrylate copolymer (made by Sumitomo Chemical Co., Ltd., WD106) and acid-modified polyethylene (Mitsubishi Chemical Co., Ltd., F515A)

PBT: The same as the PBT used for the release layer.

Then, mixing was carried out in such a manner that the blending ratio became a ratio of polypropylene:ethylene-methyl methacrylate copolymer: acid-modified polyethylene: PBT = 15:30:40:15. Further, the thickness of each layer of the obtained release film was a release layer 21: 30 μm, a buffer layer 22: 60 μm, and a release layer 23: 30 μm.

(Example 6)

A release film was produced and evaluated in the same manner as in Example 5 except that the reaction conditions related to the solid phase polymerization reaction were changed so that the IV values of the release layer 21 and the release layer 23 were 1.08.

(Example 7)

The solid phase polymerization reaction was changed so that the IV value of the release layer 21 and the release layer 23 was 1.08, and the amount of terminal carboxylic acid (AV value) of the PBT of the release layer 21 and the release layer 23 was 14.3. A release film was produced in the same manner as in Example 6 except for the reaction conditions, and evaluated.

(Example 8)

A release film was produced and evaluated in the same manner as in Example 5 except that the reaction conditions related to the solid phase polymerization reaction were changed so that the IV values of the release layer 21 and the release layer 23 were 1.14.

(Comparative Example 2)

A release film was produced in the same manner as in Example 5 except that PBT (manufactured by Toray Industries, TORAYCON product number 1100M) was used, and the IV value of the release layer 21 and the release layer 23 was changed to 0.85. .

The measurement methods and evaluation methods performed in the above Examples 5 to 8 and Comparative Example 2 will be described in detail below.

<evaluation item>

Intrinsic viscosity (IV value): determined at 35 ° C according to ASTM D2857. Specifically, the sample adjusted by the following method was used and calculated from the following formula (A).

(1) Measurement of the preparation of samples

First, about 3 to 5 g of the obtained release layer was placed in a 100 mL beaker, and then acetone was injected into the beaker. Thereafter, the sample in the beaker was dried at 105 ° C for 30 minutes using an oven. Next, in a 100 mL bottle, 0.45 to 0.5 g of the dried polymer was measured in an accuracy of 4 points below the decimal point. Next, the weight of the release layer per unit volume was diluted 100 times using an automatic measuring device so that the accuracy was ±0.01 mL. After that, the release layer was transferred to the bottle and the bottle was sealed with a tight gasket. Next, the bottle was heated at 110 ° C for about 60 to 75 minutes while stirring until the release layer was completely melted. Then, the obtained bottle was taken out from the constant temperature bath and placed in a cooling bath.

(2) Determination

First, 18 mL of the solvent measured using the measuring flask was injected into the tubular member of the viscometer to wash the inside of the tubular member. Then, after setting the tubular member of the viscometer to 35 ° C + 0.1 ° C for 10 minutes, the polymer solution was injected into the viscometer three times. Next, the inside of the viscometer was vacuumed by a pump, and the solution was sucked in the container disposed in the upper portion of the tubular member. After that, the vacuum in the viscometer is released. State, using a timer to measure the time between the two passes of the solvent through the tubular member. This measurement was performed four times, and the average value was calculated. In addition, an automatic viscometer (SCHOTT AVS-500) was used in this measurement.

(3) Calculation of IV value

An o-chlorophenol having a phenol/tetrachloroethane ratio of 3:2 at 35 ° C at 30 ° C was used as a standard sample. The IV value in the present embodiment is calculated by the following formula (A).

Formula (A): IV value = {(measurement flow time of sample / circulation time of standard sample) - 1} × 0.7789 + 0.111

The amount of terminal carboxylic acid (AV value): determined by indicator titration. Specifically, the sample adjusted by the following method was used and calculated from the following formula (B).

(1) Measurement of the preparation of samples

First, about 2 g of the obtained release layer 21 was weighed into a 100 mL bottle. Next, 50 mL of o-cresol was injected into the bottle. Then, a stirrer was placed in the bottle until the release layer was completely dissolved for about 30 minutes, and the mixture was heated and stirred at 100 ± 5 °C. After the release layer was melted, it was placed until the temperature of the solution in the bottle became 30 °C. Next, 3 mL of a 0.01 mol/L potassium chloride solution was added, and the mixture was titrated with a 0.05 mol/L ethanolic potassium hydroxide solution.

(2) Evaluation of standard samples

First, 50 mL of o-cresol was weighed into a 100 mL flask. Next, a stir bar was placed in the 100 mL flask, and 3 mL of a 0.01 mol/L potassium chloride solution was added. The titration of the standard sample was carried out using the same electrode as that used for the measurement of the sample.

(3) Calculation of AV value

It is calculated by the following formula (B). In addition, the calculation results are expressed in meq COOH/kg.

Formula (B): The amount of terminal carboxylic acid = {(the amount of KOH dropped in the measurement sample [mL] - the amount of KOH dropped in the standard sample [mL]) × the specified number of KOH × 1000} / the weight of the measured sample [ g]

Mold release property: The adhesive surface of CL (CM type) manufactured by Zesho Co., Ltd. was bonded to the release surface of the release film, and hot pressed at 195 ° C × 2 min × 6 MPa, and a tensile tester (manufactured by A&D Co., Ltd.) was used. Force gauge AD-4932A-50N), the peeling force between the release surface and the CL adhesive was measured at a speed of about 1000 mm/min in the 180° direction. The measurement is performed immediately after pressing, based on the following criteria To evaluate the release property.

○: peelable

×: not easily peeled off and film or CL cracked

Followability (finished appearance wrinkles): Measured according to the "7.5.7.2 wrinkles" of the JPCA specification.

○: wrinkle generation rate is less than 2.0%

×: wrinkle generation rate is 2.0% or more

The amount of exudation of the CL adhesive: for the presence or absence of the adhesive layer of the CL on the circuit board, the evaluation of the bleed out toward the terminal portion of the circuit according to "JPCA specification 7.5.3.6, Adhesive flow of the cover layer and bleed of the top coat" the amount. The amount of exudation is less than 150 μm .

○: The amount of exudation is less than 150 μ m

×: The amount of exudation is 150 μm or more

Formability: Formability was evaluated visually in accordance with "JPCA Standard 7.5.3.3 Bubbles". Each symbol is as follows. The number of evaluation samples was evaluated as n=100, and it was confirmed that the number of voids on the sample surface was less than 2% of the number of evaluation samples.

○: void incidence is less than 2.0%

×: The void occurrence rate is 2.0% or more

The evaluation results regarding the above evaluation items are shown in Table 1 below.

The release film of the embodiment can suppress the reaction of the functional group of the material forming the release surface of the release film during hot pressing with the material forming the surface of the object on which the release film is disposed, compared to the release film of the comparative example. Interaction, can get molded products with good quality.

[Industrial Availability]

According to the present invention, since the functional group of the material forming the release surface of the release film during hot pressing reacts with the material forming the surface of the object on which the release film is disposed and the interaction is suppressed, it can be applied to obtain a molded article having good quality. The release film and the use of the release film.

1‧‧‧ release layer

2‧‧‧buffer layer

3‧‧‧ release layer

10‧‧‧ release film

Claims (15)

A release film having a release layer comprising a polyester resin material; the amount of terminal carboxylic acid measured by indicator titration using the release layer is less than 40. The release film of claim 1, wherein the polyester resin material is a polybutylene terephthalate resin. The release film of claim 1 or 2, wherein the release layer has an intrinsic viscosity of 0.9 or more and 1.5 or less as measured according to ASTM D2857 at 35 °C. The release film of any one of claims 1 to 3, wherein the release film forms a multilayer structure. The release film according to any one of claims 1 to 4, which is formed by forming a three-layer structure of the release layer/buffer layer/the release layer. A release film according to any one of claims 1 to 5, which is laminated on the surface of a cover lay film for use. A release film according to any one of claims 1 to 5, which is laminated on the surface of a copper clad laminate for use. A method of using a release film comprising the step of disposing a release film according to any one of claims 1 to 7 on a subject, and subjecting the object to which the release film is disposed to be hot pressed (hot press) step; in the step of disposing the release film, the surface of the object to which the release film is disposed is formed of a material containing a thermosetting resin in a semi-hardened state. A release film having a release layer comprising a polyester resin material; the intrinsic viscosity of the release layer measured at 35 ° C according to ASTM D2857 is 0.9 or more and 1.5 or less. The release film of claim 9, wherein the polyester resin material is a polybutylene terephthalate resin. The release film of claim 9 or 10, wherein the release film forms a multilayer structure. The release film according to any one of claims 9 to 11, which is formed by forming a three-layer structure of the release layer/buffer layer/the release layer. A release film according to any one of claims 9 to 12, which is laminated on the surface of the cover film for use. A release film according to any one of claims 9 to 13 which is laminated on the surface of a copper clad laminate for use. A method of using a release film comprising the step of disposing a release film according to any one of claims 9 to 14 on a subject, and hot pressing the object to which the release film is disposed In the step of disposing the release film, the surface of the object to which the release film is disposed is formed of a material containing a thermosetting resin in a semi-hardened state.