JP5874774B2 - Release film and method of using release film - Google Patents

Description

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

  Examples of the release film include the following.

  Patent Document 1 discloses a polyester-based elastomer layer showing specific values for glass transition temperature and crystallization rate index, crystalline aromatic polyester and 1,4-cyclohexanedimethanol copolymerized polyethylene blended at a specific mass ratio. There is disclosed a release film comprising a polyester layer made of polyester which is made of terephthalate and has specific values for glass transition temperature and heat of crystal fusion. According to the release film described in Patent Document 1, it is excellent in flexibility, release property, heat resistance, non-contamination property, in particular, good embedding property in a printed circuit board having a precise pattern, and winding of a sheet. It is possible to provide a release film that is excellent in handling workability during removal and cutting.

  Patent Document 2 discloses a release film having a crystalline polyester layer showing specific values for the heat of crystal fusion and the crystallization speed index, and a polyester layer showing specific values for the heat of crystal fusion and the crystallization speed index. ing. According to the release film described in Patent Document 2, the sheet is excellent in flexibility, mold release property, heat resistance, non-contamination property, and particularly has good embedding property in a printed circuit board having a precise pattern, and a sheet. It is possible to provide a release film that is excellent in handling workability during winding and cutting.

  Patent Document 3 discloses a polyester-based elastomer layer having specific values for a glass transition temperature and a crystallization rate index, a specific crystallization start temperature at a temperature rise, a temperature rise crystallization peak temperature, and a temperature rise crystallization heat amount. A release film having a copolyester layer exhibiting a value is disclosed. According to the release film described in Patent Document 3, it is excellent in flexibility, release property, heat resistance, and non-contamination property, and in particular, a high level of embedding property and release property on a printed circuit board having a precise pattern. And a release film excellent in handling workability at the time of winding and cutting of the sheet.

JP 2011-88351 A JP 2011-88352 A JP 2011-245812 A

The release films described in Patent Documents 1 and 2 are required to satisfy the following four properties in a well-balanced manner.
(1) The mold release film can be easily peeled off from the wiring board after thermoforming (mold release property).
(2) The release films adhered to each other easily peel off at the outer peripheral portion of the wiring board (low self-bonding property).
(3) At the time of thermoforming, it follows the unevenness of the circuit wiring provided on the substrate surface well, fills the space between the circuit wirings, and prevents the adhesive from oozing between the circuit wirings from the coverlay (CL). (Good embeddability).
(4) Good compatibility between the compounding resins of the release film.

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

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

  When the release film described in Patent Documents 1 to 3 is used, when heat-pressing, the functional group of the material that forms the release surface of the release film and the surface of the object on which the release film is arranged are formed. The material sometimes reacted and interacted. In such a case, after the release film was peeled off, a part of the release film remained as a contaminant on the object, and a new problem was found that a good molded product could not be obtained.

  In view of the above circumstances, in the present invention, when hot pressing, the functional group of the material forming the release surface of the release film reacts with the material forming the surface of the object on which the release film is arranged. It is intended to provide a release film that can suppress the interaction and obtain a molded product having good quality.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors measured at 35 ° C. according to ASTM D2857 when forming a release film having a first release layer containing a polyester resin material. The inventors have found that the measure of the intrinsic viscosity of the first release layer is effective as a design guideline, and have reached the present invention.

According to the present invention, a release film having a first release layer containing a polyester resin material,
The intrinsic viscosity of the first release layer measured at 35 ° C. according to ASTM D2857 is 0.9 or more and 1.5 or less,
The average length of roughness curve element of the first releasing layer (Rsm) is Ri der than 90 [mu] m,
The polyester resin material is a polybutylene terephthalate resin,
A release film having a glossiness of 6 to 150, which is a reflectance of light at an incident angle of 60 °, of the first release layer is provided.

Furthermore, according to the present invention, the step of disposing the release film on the object so that the first release layer of the release film is on the object side;
A step of performing a heat press on the object on which the release film is disposed,
Including
In the step of disposing the release film, a method of using the release film in which a surface of the object on which the release film is disposed is formed of a material containing a semi-cured thermosetting resin is provided. The

  According to the present invention, when heat-pressing, the functional group of the material forming the release surface of the release film reacts with the functional group of the material forming the surface of the object on which the release film is arranged. It is possible to provide a release film capable of suppressing the interaction and obtaining a molded product having good quality.

It is sectional drawing of the release film which concerns on this embodiment. It is sectional drawing of the release film which concerns on this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

<Release film>
A release film 10 according to the present embodiment is a release film 10 having a release layer 1 (first release layer) containing a polyester resin material, and the release film measured at 35 ° C. according to ASTM D2857. The intrinsic viscosity of the layer 1 is 0.9 or more and 1.5 or less (see FIG. 1). In this way, when heat-pressing, the functional group of the material that forms the release surface of the release film 10 and the material that forms the surface of the object on which the release film 10 is arranged react and interact. The release film 10 which can suppress that and can obtain the molded article with favorable quality can be obtained.

  In the release film 10 according to this embodiment, the release layer 1 is also referred to as a surface (hereinafter referred to as “release surface”) that contacts at least the release film 10 when the release film 10 is disposed on the object. The polyester resin is a polycondensate of a polyvalent carboxylic acid (dicarboxylic acid) and a polyalcohol (diol), and is a compound having a plurality of carboxyl groups (—COOH).

  Moreover, the object surface before arrange | positioning a release film is normally formed with the material containing the thermosetting resin of a semi-hardened state. The release film 10 according to the present embodiment is used by being disposed on the surface of an object formed of a material containing the semi-cured thermosetting resin. And a molded article can be obtained by performing a heat press in the state which has arrange | positioned the said release film 10 on the target object surface.

When a conventional release film is used, it is estimated that the following phenomenon occurs.
Conventionally, it is considered that a carboxyl group in a material that forms a release surface in a release film reacts with an unreacted functional group of the coverlay film adhesive during a hot press, and may interact with it. . Such an unreacted functional group is not particularly limited, and examples thereof include an epoxy group as a functional group that easily interacts.
Hereinafter, the 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 is used, the reason why a part of the release film remains as a contaminant on the coverlay film is not necessarily clear, but a polar group such as a carboxyl group Is considered to be involved in the contamination of the molded product.

  And the intrinsic viscosity of the mold release layer 1 of the conventional mold release film described in patent documents 1-3 etc. measured at 35 degreeC according to ASTM D2857 differs from the mold release film 10 which concerns on this embodiment. It was technical level. Thus, in the case of a conventional release film using a polyester resin material, a polar group such as a carboxyl group in the material forming the release surface and an unreacted functional group that the coverlay film adhesive has The reaction and interaction could not be sufficiently suppressed.

  On the other hand, according to the release film 10 according to the present embodiment, the intrinsic viscosity of the release layer 1 measured at 35 ° C. according to ASTM D2857 is obtained by hot pressing in order to satisfy the above specific conditions. In the molded body, the surface of the molded product is prevented from remaining on the surface of the molded product after the molded product and the release film 10 are peeled off, and the molded product surface is roughened. It is possible to obtain an excellent mold release property that can prevent this. This is because the intrinsic viscosity measured at 35 ° C. according to ASTM D2857 of the release layer 1 containing the polyester resin material that forms the release surface is 0.9 to 1.5. This is probably because the amount of carboxyl groups interacting with unreacted functional groups present on the surface is reduced compared to the conventional case. For this reason, the release film 10 which concerns on this embodiment can obtain the mold release property excellent in comparison with the conventional release film.

  The roughness generated on the surface of the molded product means that a part of the surface of the molded product is wavy, a part of the surface of the molded product is curled, the shape of the surface of the molded product is not smooth, and is rough.

  Further, in the release film 10 according to this embodiment, the intrinsic viscosity of the release layer 1 measured at 35 ° C. according to ASTM D2857 may be 0.9 or more and 1.5 or less, but 1.0 or more. More preferably, it is 1.3 or less. By carrying out like this, when heat-pressing, the functional group of the material which forms the release surface of the release film 10 reacts with the functional group of the material which forms the surface of the object on which the release film 10 is arranged. Thus, a molded product having good quality can be obtained.

  In the present embodiment, the polyester resin material is not particularly limited, and examples thereof include polyalkylene terephthalate resins such as polyethylene terephthalate resin, polybutylene terephthalate resin, polytrimethylene terephthalate resin, and polyhexamethylene terephthalate resin. Among these, it is preferable to use polybutylene terephthalate resin. By doing so, the functional group of the material that forms the release surface of the release film 10 reacts with the functional group of the material that forms the surface of the object on which the release film 10 is arranged when performing heat pressing. Thus, a molded product having good quality can be obtained.

  Further, the polyester resin material may be a polyester copolymer resin copolymerized with other components as necessary. Examples of the copolymerizable component include known acid components, alcohol components, phenol components, derivatives thereof having an ester-forming ability, polyalkylene glycol components, and the like.

  Moreover, as an acid component which can be copolymerized, for example, a divalent or higher valent aromatic carboxylic acid having 8 to 22 carbon atoms, a divalent or higher valent aliphatic carboxylic acid having 4 to 12 carbon atoms, and 2 Examples thereof include alicyclic carboxylic acids having a carbon number of 8 to 15 or more and those having an ester forming ability. Specific examples of the acid component that can be copolymerized include, for example, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, bis (p-carbodiphenyl) methaneanthracene dicarboxylic acid, 4-4′-diphenylcarboxylic acid, 1 , 2-bis (phenoxy) ethane-4,4′-dicarboxylic acid, 5-sodium sulfoisophthalic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, maleic acid, trimesic acid, trimellitic acid, pyromellitic acid 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and derivatives thereof having ester forming ability. These can be used alone or in combination of two or more.

  Examples of alcohol components and / or phenol components that can be copolymerized or derivatives thereof having ester-forming ability include, for example, dihydric or higher aliphatic alcohols having 2 to 15 carbon atoms and divalent or higher carbon numbers. Examples thereof include 6 to 20 alicyclic alcohols, bivalent or higher aromatic alcohols having 6 to 40 carbon atoms, and phenol and derivatives thereof having ester forming ability. Specific examples of the copolymerizable alcohol component and / or phenol component or these derivatives having ester-forming ability include ethylene glycol, propanediol, butanediol, hexanediol, decanediol, neopentylglycol, cyclohexanedimethanol, Compounds such as cyclohexanediol, 2,2′-bis (4-hydroxyphenyl) propane, 2,2′-bis (4-hydroxycyclohexyl) propane, hydroquinone, glycerin, pentaerythritol, and derivatives thereof having ester forming ability And cyclic esters such as ε-caprolactone.

  Examples of the polyalkylene glycol component that can be copolymerized include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and random or block copolymers thereof, alkylene glycols of bisphenol compounds (polyethylene glycol, polypropylene glycol, poly And modified polyoxyalkylene glycols such as adducts such as tetramethylene glycol and random or block copolymers thereof.

  Among such polyester copolymer resins, a copolymer of a polyester resin material and a polyalkylene glycol component is preferable, more specifically, a copolymer of a polyester resin and polytetramethylene glycol, more specifically, Specifically, a copolymer of polybutylene terephthalate resin and polytetramethylene glycol is preferable. Thereby, the mold release film 10 which was excellent also in terms of plating property can be obtained.

  The content of other components that can be copolymerized (particularly polytetramethylene glycol) is not particularly limited, but is preferably 5% by weight or more and 50% by weight or less of the entire polyester-based copolymer resin, In particular, it is preferably 10% by weight or more and 40% by weight or less. When content is more than the said lower limit, the followable | trackability to the target object of the said release film 10 can be improved. Moreover, when content is below the said upper limit, mold release property can further be improved.

  In addition to the polyester resin material, the material that forms the release surface includes antioxidants, slip agents, antiblocking agents, antistatic agents, coloring agents such as dyes and pigments, additives such as stabilizers, fluororesins Further, an impact resistance imparting agent such as silicon rubber, and an inorganic filler such as titanium oxide, calcium carbonate, and talc may be contained.

  Moreover, it is preferable that the amount of terminal carboxylic acids measured by the indicator titration method using the release layer 1 of the release film 10 which concerns on this embodiment is less than 40, It is more preferable that it is 30 or less, 25 or less More preferably. By doing so, the functional group of the material that forms the release surface of the release film 10 reacts with the functional group of the material that forms the surface of the object on which the release film 10 is arranged when performing heat pressing. Thus, a molded product having good quality can be obtained.

  In addition, the amount of 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 release film 10 according to this embodiment. Met. Thus, when the conventional release film is used, the unreacted functional group in the object reacts with and interacts with the polar group in the material forming the release surface of the release layer 1. It was not possible to suppress it sufficiently.

1 and 2 are cross-sectional views of a release film 10 according to this embodiment.
The release film 10 according to this embodiment may have a single layer structure or a multilayer structure. As shown in FIG. 1, when the release film 10 has a single layer structure, the manufacturing process of the release film 10 can be simplified. On the other hand, as shown in FIG. 2, if the layer structure of the release film 10 is a multilayer structure, the releasability and followability with the object can be adjusted as appropriate.

  Hereinafter, as the release film 10 according to the present embodiment, an example in which the multilayer structure shown in FIG. 2 is formed will be described.

  As shown in FIG. 2, the release film 10 according to this embodiment includes a release layer 1, a cushion layer 2, and a release layer 3 (second release layer) laminated in this order. Hereinafter, each layer will be described in order.

  First, the release layer 1 retains releasability from the object surface. Moreover, the function of the pattern followability which the release layer 1 follows according to the shape of the target object which arrange | positions the said release film 10 is also provided. The release layer 1 is a layer that forms a release surface, and is formed of a polyester resin material.

  Moreover, as a method of forming the release layer 1, well-known methods, such as an air cooling or a water cooling inflation extrusion method and a T-die extrusion method, are mentioned, for example.

  The thickness of the release layer 1 is not particularly limited, but is preferably 5 μm or more, more preferably 7 μm or more, further preferably 15 μm or more, and even more preferably 20 μm or more from the viewpoint of improving the embedding property with respect to the object. On the other hand, from the viewpoint of obtaining an appropriate strength, it is preferably 40 μm or less, and more preferably 30 μm or less.

Further, the viscoelastic modulus at 180 ° C. of the release layer 1 is not particularly limited, but 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 viscoelastic modulus of the release layer 1 is equal to or more than the lower limit value, it is possible to suppress a decrease in release properties of the release film 10. Moreover, when the viscoelastic modulus of the release layer 1 is equal to or lower than the above upper limit value, it is possible to suppress a decrease in embedding property of the release film 10.
In addition, the viscoelastic modulus of the release layer 1 can be evaluated by, for example, measuring from normal temperature to 250 ° C. in a tensile mode, a frequency of 1 Hz, and a heating rate of 5 ° C./min with a dynamic viscoelasticity measuring device.

The release layer 1 preferably has a glossiness of 6 to 150, more preferably 6 to 145, which is the reflectance of light at an incident angle of 60 °.
Specifically, the glossiness can be set in accordance with Japanese Industrial Standard (JIS) Z8741. In other words, this standard specifies a test method for measuring the specular gloss of a coating film using a reflectometer with a geometric condition of an incident angle of 20 °, 60 ° or 85 ° (suitable for measuring the glossiness of metallic paints). In the case of an incident angle of 60 ° on a surface having a refractive index of 1.567, the reflectance is 10% when the gloss is 100 (gloss (60 °) = 100%) and the incident angle is 20 °. 5% is defined as a glossiness of 100 (gross (20 °) = 100%). Of these, the glossiness is determined by the reflectance of light at an incident angle of 60 °.
Note that the glossiness of the release layer 1 is a numerical value of the surface of the release layer 1 on the object side to be pressed.

By setting the glossiness to the above value while setting the intrinsic viscosity of the release layer 1 to 0.9 or more and 1.5 or less, a good release property can be obtained. Molding with good quality by suppressing the reaction and interaction between the functional group of the material forming the mold surface and the functional group of the material forming the surface of the object on which the release film 10 is disposed. Goods can be obtained.
In this case, the glossiness of the release layer 3 is preferably 10 to 150. Thereby, the release layer 1 and the release layer 3 can be easily distinguished, and the front and back of the release film 10 can be easily distinguished.

Further, the average length (Rsm) of the roughness curve element of the release layer 1 is preferably 90 μm or more from the viewpoint of obtaining good release properties, and 450 μm from the viewpoint of obtaining a molded product of good quality. Or less, and more preferably 350 μm or less.
The average length (Rsm) of the roughness curve element can be measured according to JIS-B0601-2001.
In addition, the average length (Rsm) of the roughness curve element of the release layer 1 is a numerical value of a surface corresponding to the object to be pressed of the release layer 1.

By setting the average length (Rsm) of the roughness curve element to the above value while setting the intrinsic viscosity of the release layer 1 to 0.9 or more and 1.5 or less, a good release property can be obtained, and a hot press In this case, the functional group of the material that forms the release surface of the release film 10 and the functional group of the material that forms the surface of the object on which the release film 10 is arranged are prevented from reacting and interacting with each other. In addition, a molded product having good quality can be obtained.
In this case, the average length (Rsm) of the roughness curve element of the release layer 3 is preferably 90 μm or more, more preferably 150 μm or more, while 450 μm or less is preferable, and 400 μm or less. More preferably. Thereby, the release layer 1 and the release layer 3 can be easily distinguished, and the front and back of the release film 10 can be easily distinguished.

The surface layer 10-point average roughness (Rz) of the release layer 1 is preferably 0.5 μm or more from the viewpoint of obtaining good release properties while ensuring the strength of the release layer 1. 0 μm or more is more preferable, and 1.2 μm or more is more preferable. On the other hand, from the viewpoint of suppressing the transfer of the surface roughness, it is preferably 15 μm or less, more preferably 10 μm or less, and even more preferably 8 μm or less.
The surface 10-point average roughness (Rz) can be measured according to JIS-B0601-2001.
In addition, the surface 10-point average roughness (Rz) of the release layer 1 is a numerical value of a surface corresponding to the object to be pressed of the release layer 1.

When the intrinsic viscosity of the release layer 1 is 0.9 or more and 1.5 or less and the surface 10-point average roughness (Rz) is set to the above value, good release properties can be obtained, and when hot pressing is performed. The functional group of the material forming the release surface of the release film 10 and the functional group of the material forming the surface of the object on which the release film 10 is disposed are inhibited from reacting and interacting with each other, A molded product having good quality can be obtained.
In this case, the surface 10 point average roughness (Rz) of the release layer 3 to be described later is preferably 0.5 μm or more, more preferably 0.6 μm or more, and on the other hand, 15 μm or less is preferable. The following is more preferable. Thereby, the release layer 1 and the release layer 3 can be easily distinguished, and the front and back of the release film 10 can be easily distinguished.

  Such a surface shape of the release layer 1 can be obtained by a known method.

  Next, the cushion layer 2 has a cushion function for embedding the release layer 1 of the release film 10 in a gap between adjacent object surfaces. Moreover, by setting it as the release film 10 which has the cushion layer 2, when applying heat press, the pressure concerning the whole target object which has arrange | positioned the release film 10 can be made uniform. Furthermore, when manufacturing a flexible circuit board, the appearance finish (especially, the occurrence of wrinkles) can be made excellent.

  The cushion layer 2 is formed of a second resin different from the polyester resin material. In this case, examples of the second resin include a polyester resin material or a resin other than the polyester resin material having a composition different from that of the polyester resin material forming the release layer 1. Among these, resins other than the polyester resin material forming the release layer 1 are preferable.

  Examples of the cushion layer 2 include α-olefin polymers such as polyethylene and polypropylene, α-olefin copolymers having a copolymer component such as ethylene, propylene, butene, pentene, hexene, and methylpentene, and polyethersulfone. Engineering plastics resins such as polyphenylene sulfide may be used, and these may be used alone or in combination. Of these, α-olefin copolymers are preferred. Specifically, a copolymer of α-olefin such as ethylene and (meth) acrylic acid ester, a copolymer of ethylene and vinyl acetate, a copolymer of ethylene and (meth) acrylic acid, and those Partially ionically crosslinked products and the like can be mentioned. Furthermore, from the viewpoint of obtaining a good cushion function, one using an α-olefin- (meth) acrylic acid ester copolymer such as ethylene alone, or polybutylene terephthalate and 1,4 cyclohexanedimethanol copolymer polyethylene A mixture of terephthalate, an α-olefin polymer, and a mixture of an α-olefin- (meth) acrylic acid ester copolymer such as ethylene is preferable. For example, a mixture of ethylene and an ethylene-methyl methacrylate copolymer, polypropylene and A mixture with an ethylene-methyl methacrylate copolymer is more preferable.

Among these second resins, in particular, the cured product of the second resin preferably has an elastic modulus at 90 ° C. of 10 MPa or less, particularly 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, particularly when a flexible circuit is manufactured, the release film 10 having an excellent cushion function can be obtained.
The elastic modulus can be evaluated, for example, by measuring from normal temperature to 250 ° C. with a dynamic viscoelasticity measuring device at a tensile mode, a frequency of 1 Hz, and a temperature rising rate of 5 ° C./min.

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

  Examples of the rubber component include thermoplastic elastomer materials such as styrene-based thermoplastic elastomers such as styrene-butadiene copolymer and styrene-isoprene copolymer, olefin-based thermoplastic elastomers, amide-based elastomers, and polyester-based elastomers, and natural rubber. And rubber materials such as isoprene rubber, chloroprene rubber and silicon rubber.

  Further, the content of the rubber component in the cushion layer 2 is not particularly limited, but is preferably 5 parts by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the second resin, and is 10 parts by weight or more and 40 parts by weight or less. More preferably. When the content of the rubber component in the cushion layer 2 is within the above range, the release film 10 having further excellent cushioning properties can be obtained.

  In addition to the second resin, the cushion layer 2 includes an antioxidant, a slip agent, an antiblocking agent, an antistatic agent, a coloring agent such as a dye and a pigment, an additive such as a stabilizer, a fluororesin, and a silicone rubber. An impact resistance imparting agent such as titanium oxide, calcium carbonate, talc and other inorganic fillers may be included.

  In addition, as a method of forming the cushion layer 2, well-known methods, such as an air cooling or a water cooling inflation extrusion method and a T-die extrusion method, are mentioned, for example.

  The thickness of the cushion layer 2 is not particularly limited, but is preferably 30 μm or more and 100 μm or less, more preferably 50 μm or more and 90 μm or less, and further preferably 50 μm or more and 70 μm or less. When the thickness of the cushion layer 2 is not less than the above lower limit value, it can be suppressed that the cushioning property of the release film 10 is lowered. When the thickness of the cushion layer 2 is not more than the above upper limit value, it is possible to suppress a decrease in releasability.

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

The mold release layer 3 retains mold release properties with a backing plate used during molding such as a hot press.
The release layer 3 is composed of a third resin having a softening point higher than that of the second resin. Thereby, the mold release property with a backing plate can be improved further.

  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, 1-hexene, 1-octene, 1 -Copolymers with α-olefins having 2 to 20 carbon atoms such as decene, 1-tetradecene, 1-octadecene, olefin resins such as polypropylene, polyester resins similar to those used in the release layer 1 Can be mentioned.

  Further, the third resin and the polyester resin material forming the release layer 1 may be the same or different, but are preferably the same.

  The softening point of the third resin is not particularly limited, but is preferably 100 ° C. or higher, and more preferably 120 ° C. or higher. Thereby, in addition to releasability, it can reduce that the volatile component or the 3rd resin resulting from the 3rd resin adheres to the backing plate comprised with the SUS board etc.

  In addition to the third resin, the release layer 3 includes an antioxidant, a slip agent, an antiblocking agent, an antistatic agent, a coloring agent such as a dye and a pigment, an additive such as a stabilizer, a fluororesin, and a silicone rubber. An impact resistance imparting agent such as titanium oxide, calcium carbonate, talc and other inorganic fillers may be included.

  In addition, as a method of forming the mold release layer 3, well-known methods, such as an air cooling or a water cooling inflation extrusion method and a T-die extrusion method, are mentioned, for example.

  Further, the thickness of the release layer 3 is not particularly limited, but is preferably 5 μm or more from the viewpoint that the entire release film 10 becomes rigid when heat-pressed and the release property is improved. More preferably, it is more preferably 15 μm or more. On the other hand, from the viewpoint that the film forming property of the release film 10 is suitable, it is preferably 60 μm or less, more preferably 50 μm or less, and further preferably 45 μm or less.

  The release film 10 according to the present embodiment preferably has a three-layer structure of release layer 1 / cushion layer 2 / release layer 3. Moreover, although the thickness of the release film 10 whole is not specifically limited, 40 micrometers or more and 250 micrometers or less are preferable, 80 micrometers or more and 180 micrometers or less are more preferable, 90 micrometers or more and 150 micrometers or less are more preferable.

  Moreover, in the release film 10 of this embodiment, although what was comprised by the release layer 1, the cushion layer 2, and the release layer 3 was shown, this invention is not limited to this, An adhesive layer Further, it may have a configuration of four or more layers such as four layers and five layers having a gas barrier layer.

Further, the release film 10 according to the present embodiment is not particularly limited, but may be disposed inside a mold including an upper mold and a lower mold, or may be separated on a coverlay film or a copper clad laminate. You may arrange | position and use so that the type | mold layer 1 side may contact | connect. Among these, when it arrange | positions on a cover-lay film or a copper clad laminated board, it can fully exhibit the release property of the release film 10 which concerns on this embodiment.
Examples of the object using the release film 10 include a coverlay film and a copper clad laminate. This object is an object formed of a material containing a thermosetting resin in which at least the surface before being heated and pressed is in a semi-cured state. Moreover, as a thermosetting resin, an epoxy resin, an acrylic resin, a polyester resin, an imide resin etc. are mentioned, for example.

<Method for producing release film>
The release film 10 according to the present embodiment may be obtained by separately manufacturing such a release layer 1, the cushion layer 2, and the release layer 3, and then joining them with a laminator or the like. A method of obtaining the release layer 1, the cushion layer 2, and the release layer 3 by a method of forming a film by, for example, an air cooling type or a water cooling type coextrusion inflation method or a coextrusion T die method is preferable. Especially, the method of forming into a film by the co-extrusion T die method is especially preferable at the point which is excellent in the thickness control of each layer.
Moreover, the release layer 1, the cushion layer 2, and the release layer 3 may be joined as they are, or may be joined via an adhesive layer.

Conventionally, for example, a release film has been produced using a polyester resin material obtained by performing a polycondensation reaction in a molten state. Thus, producing a release film using a polyester resin material obtained by polycondensation itself has been performed in the prior art.
On the other hand, the release layer 1 and / or the release layer 3 forming the release surface in the release film 10 according to the present embodiment is not a conventional polycondensation reaction, but is obtained, for example, by solid phase polymerization. It is produced using the obtained polyester resin material.

  The release film 10 according to the present embodiment is a polymer used in a solid phase polymerization reaction in order to control the intrinsic viscosity of the release layer 1 measured at 35 ° C. according to ASTM D2857 to 0.9 or more and 1.5 or less. It can be obtained for the first time by controlling the reaction conditions such as the type of catalyst, reaction temperature, and reaction time. When the release film 10 according to the present embodiment is heated and pressed, the functional group of the material forming the release surface of the release film 10 and the functionality of the material forming the surface of the object on which the release film 10 is arranged. It is particularly important to control these factors in order to prevent the group from reacting and interacting with each other and to obtain a molded product having good quality.

<Usage of release film>
Next, the usage method of the release film 10 of this embodiment is demonstrated.
First, the release film 10 according to the present embodiment is disposed on the surface of an object formed of a material containing a semi-cured thermosetting resin so that the release layer 1 is on the object side. . And it heat-presses in the metal mold | die with respect to the target object in which the release film 10 is arrange | positioned. By carrying out like this, it can suppress that the polar group in the release film 10 reacts and interacts with the unreacted functional group in the material which forms the target object surface. As a result, in a molded product obtained by hot pressing, it is possible to prevent a very small amount of foreign matter and a part of the release film 10 from adhering to the surface of the molded product after the molded product and the release film 10 are peeled off. Since the surface of the molded product can be prevented from being roughened, the functional group of the material forming the release surface of the release film 10 and the surface of the object on which the release film 10 is arranged when hot pressing is performed. It is possible to suppress the reaction and interaction with the functional group of the material forming the material and obtain a molded product having good quality.

  As mentioned above, although embodiment of this invention was described, these are illustrations of this invention and various structures other than the above are also employable.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to these. In this embodiment, the release film 10 having a three-layer structure shown in FIG. 2 will be described below as an example.

<Manufacture of release film>
Example 1
1. Production of polyester resin material The content of 2- (4′-hydroxybutoxy) tetrahydrofuran (hereinafter referred to as “HTHF”) is 0 with respect to 1,4-butylene glycol (hereinafter referred to as “BG”). 1104 g of BG that is 4 wt%, and 1132 g of TPA (BG / TPA molar ratio of 1.8) whose acetic acid content is 0.14 wt% with respect to terephthalic acid (hereinafter referred to as “TPA”). An esterification reaction and then a polycondensation reaction were performed.

First, the total amount of TPA, BG750g, titanium tetra-n-butoxide 0.8g, monobutylhydroxytin oxide 0.7g was charged into a reactor equipped with a rectifying column, and the esterification reaction was started at 190 ° C and 400mmHg. Then, the temperature was gradually raised and the remaining BG was continuously added.
To this reaction product, 0.08 g of titanium tetra-n-butoxide and 0.01 g of phosphoric acid were added, and a polycondensation reaction was performed at 250 ° C. and 0.5 mmHg.
The fine polymer particles produced were charged into 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 degree of polymerization polybutylene terephthalate (hereinafter referred to as PBT).

2. Production of Release Film Release layer 1 made of PBT produced by the above method, cushion layer 2 made of polypropylene, modified polyethylene and PBT produced by the above method, and release layer 3 made of PBT produced by the above method A release film was produced by heat-pressing a release film consisting of three layers. The intrinsic viscosity (IV value) of the release layer 1 and the release layer 3 were both 1.22.
More specifically, the cushion layer 2 was formed using the following materials.
Polypropylene: manufactured by Sumitomo Chemical Co., Ltd., FH1016
Modified polyethylene: ethylene-methyl methacrylate copolymer (manufactured by Sumitomo Chemical Co., Ltd., WD106) and acid-modified polyethylene (manufactured by Mitsubishi Chemical Corporation, F515A)
PBT: The same PBT used for the release layer 1 was used.
Then, blending was performed so that the blending ratio was a ratio of polypropylene: ethylene-methyl methacrylate copolymer: acid-modified polyethylene: PBT = 15: 30: 40: 15.
The thickness of each layer of the obtained release film was a release layer 1:30 μm, a cushion layer 2: 60 μm, and a release layer 3:30 μm.

(Example 2)
A release film was prepared 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 IV values of the release layer 1 and the release layer 3 were 1.08. Evaluation was performed.

(Example 3)
The IV value of release layer 1 and release layer 3 is 1.08, and the amount of PBT terminal carboxylic acid (AV value) of release layer 1 and release layer 3 is 14.3. A release film was prepared and evaluated in the same manner as in Example 2 except that the reaction conditions related to the polymerization reaction were changed.

Example 4
A release film was prepared in the same manner as in Example 1 except that the reaction conditions for the solid phase polymerization reaction were changed so that the IV values of the release layer 1 and the release layer 3 were 1.14. Evaluation was performed.

(Comparative Example 1)
A release film was prepared in the same manner as in Example 1 except that PBT (Toray Industries Inc., Toraycon product number 1100M) was used so that the IV value of release layer 1 and release layer 3 was 0.85. Fabricated and evaluated.

  The measurement methods and evaluation methods performed for Examples 1 to 4 and Comparative Example 1 are described in detail below.

<Evaluation items>
Intrinsic viscosity (IV value): measured at 35 ° C. according to ASTM D2857. Specifically, it calculated from the following formula (A) using a sample prepared by the following method.
(1) Preparation of measurement sample First, about 3 to 5 g of the obtained release layer was placed in a 100 mL beaker, and then acetone was poured into the beaker. Thereafter, the sample in the beaker was dried at 105 ° C. for 30 minutes using an oven. Next, about 0.45 to 0.5 g of dry polymer was measured in a 100 mL bottle with an accuracy of 4 digits after the decimal point. Next, using an automatic measuring device, the release layer weight per unit volume was diluted 100 times so that the accuracy would be ± 0.01 mL. Thereafter, the release layer was transferred to a bottle, and the bottle was sealed using a gasket. The bottle was then heated at 110 ° C. for about 60-75 minutes with stirring until the release layer was completely melted. And the obtained bottle was taken out from the thermostat, and was mounted in the cooling tank.
(2) Measurement First, 18 mL of solvent weighed using a volumetric flask was poured into the tubular member of the viscometer to wash the inside of the tubular member. And 10 minutes after setting the tubular member of the viscometer to 35 ° C. + 0.1 ° C., the polymer solution was poured into the viscometer three times. Next, the inside of the viscometer was evacuated using a pump, and the solution was sucked into a container arranged on the upper part of the tubular member. Thereafter, the vacuum state in the viscometer was released, and the time for the solvent to pass between the two locations in the tubular member was measured using a chronometer. This measurement was performed 4 times, and the average value was calculated. For this measurement, an automatic viscometer (SCHOTT AVS-500) was used.
(3) Calculation of IV Value As a standard sample, o-chlorophenol at 35 ° C. having a phenol / tetrachloroethane ratio of 3: 2 at 30 ° C. was used. The IV value in this example was calculated from the following formula (A).
Formula (A): IV value = {(circulation time of measurement sample / circulation time of standard sample) −1} × 0.7789 + 0.111

Terminal carboxylic acid content (AV value): Measured by indicator titration method. Specifically, it calculated from the following formula (B) using a sample prepared by the following method.
(1) Preparation of measurement sample First, 1 to 2 g of the obtained release layer was weighed into a 100 mL bottle. Next, 50 mL of o-cresol was poured into the bottle. A stirrer 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 solution temperature in the bottle reached 30 ° C. Next, 3 mL of 0.01 mol / L potassium chloride solution was added, and titrated with 0.05 mol / L ethanolic potassium hydroxide solution.
(2) Evaluation of standard sample First, 50 mL of o-cresol was weighed into a 100 mL flask. Next, a stirrer bar was placed in the 100 mL flask, and 3 mL of 0.01 mol / L potassium chloride solution was added.
(3) Calculation of AV value It calculated from the following formula | equation (B). The calculation result is expressed as meq COOH / kg.
Formula (B): Amount of terminal carboxylic acid = {(KOH amount dropped to measurement sample [mL] −KOH amount dropped to standard sample [mL]) × KOH prescribed number × 1000} / weight of measurement sample [ g]

Releasability: Adhesive surface of CL (CM type) manufactured by Arisawa Manufacturing Co., Ltd. was bonded to the release surface of the release film, heat pressed at 195 ° C x 2 minutes x 6 MPa, and a tensile tester (A & D) Force gauge AD-4932A-50N) was used to measure the peel force between the release surface and the CL adhesive at a speed of about 1000 mm / min in the 180 ° direction. The measurement was performed immediately after pressing, and the releasability was evaluated based on the following criteria.
○: Peelable ×: Peeling is heavy and film or CL breaks

Followability (finished appearance wrinkle): A polyimide film of CL (CM type) manufactured by Arisawa Manufacturing Co., Ltd. was bonded to the release surface of the release film, and then the release film was heat-pressed at 195 ° C. × 2 minutes × 6 MPa. The surface of CL was measured in accordance with the “7.5.7.2 wrinkle” of the JPCA standard.
○: Wrinkle occurrence rate less than 2.0% ×: Wrinkle occurrence rate 2.0% or more

CL adhesive exudation amount: CL (CM type) polyimide surface manufactured by Arisawa Manufacturing Co., Ltd. was bonded to the release surface of the release film, and then the release film was heat-pressed at 195 ° C. × 2 minutes × 6 MPa. In accordance with “JPCA Standard 7.5.3.6 Coverlay Adhesive Flow and Covercoat Bleeding”, whether or not the CL adhesive layer seeps out on the circuit board. The amount of seepage into the circuit terminal was evaluated. The exudation amount was less than 150 μm as acceptable.
○: Exudation amount less than 150 μm ×: Exudation amount 150 μm or more

Formability: A polyimide surface of CL (CM type) manufactured by Arisawa Manufacturing Co., Ltd. was bonded to the release surface of the release film, heat-pressed at 195 ° C. × 2 minutes × 6 MPa, the release film was peeled off, and CL The surface of was evaluated visually according to “bubbles in 7.5.3.3 of the JPCA standard”. Each code is as follows. Evaluation was performed with n = 100 as the number of evaluation samples, and the number of voids confirmed on the sample surface was less than 2% of the number of evaluation samples.
○: Void generation rate less than 2.0% ×: Void generation rate 2.0% or more

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

(Examples 5 to 10 and Reference Example 1 )
Next, a release film was prepared in the same manner as in Example 1 except that the release layer 1, cushion layer 2, and release layer 3 shown in Table 2 were used, and evaluation was performed in the same manner. It was.
The PBT is the same as that used in Example 1.

<Evaluation items>
Glossiness: The reflectance of light at an incident angle of 60 ° was measured in accordance with Japanese Industrial Standard (JIS) Z8741.
Rz: Measured according to JIS-B0601-2001.
Rsm: Measured according to JIS-B0601-2001.
The evaluation results are shown in Table 2.

  The release film of the example forms the functional surface of the material that forms the release surface of the release film and the surface of the object on which the release film is arranged, when heated and pressed, compared to the release film of the comparative example. The functional group of the material to be reacted was prevented from reacting and interacting, and a molded product having good quality could be obtained.

In each of Examples 5 to 10 and Reference Example 1 , the evaluation of the releasability, the followability, the amount of CL adhesive exudation, and the moldability was good. Moreover, the reference example 1 was a little inferior in followability compared with the other Examples 5-10.
Hereinafter, examples of the reference form will be added.
1. A release film having a first release layer containing a polyester resin material,
A release film, wherein the first release layer has an intrinsic viscosity of 0.9 or more and 1.5 or less measured at 35 ° C. according to ASTM D2857.
2. 1. The polyester resin material is a polybutylene terephthalate resin A release film as described in 1.
3. 1. having a cushion layer on the first release layer; Or 2. A release film as described in 1.
4). 1. Glossiness which is a reflectance of light at an incident angle of 60 ° of the first release layer is 6 to 150. To 3. A release film according to any one of the above.
5. 1. The thickness of the first release layer is 20 μm or more and 30 μm or less. To 4. A release film according to any one of the above.
6). 1. The average length (Rsm) of the roughness curve element of the first release layer is 90 μm or more. To 5. A release film according to any one of the above.
7). 2. The release film further includes a second release layer, and forms a three-layer structure in which the first release layer, the cushion layer, and the second release layer are laminated in this order. To 6. A release film according to any one of the above.
8). 2. The cushion layer is formed using a mixture of an α-olefin polymer and an α-olefin- (meth) acrylate copolymer. To 7. A release film according to any one of the above.
9. 1. Used in such a manner that the first release layer side is in contact with the surface of the coverlay film or copper clad laminate. To 8. A release film according to any one of the above.
10.1. Thru 9. Placing the release film on the object such that the first release layer of the release film according to any one of the above is on the object side;
A step of performing a heat press on the object on which the release film is disposed;
Including
In the step of disposing a release film, a method for using a release film, wherein a surface of the object on which the release film is disposed is formed of a material containing a semi-cured thermosetting resin.

DESCRIPTION OF SYMBOLS 1 Release layer 2 Cushion layer 3 Release layer 10 Release film

Claims (7)

A release film having a first release layer containing a polyester resin material,
The intrinsic viscosity of the first release layer measured at 35 ° C. according to ASTM D2857 is 0.9 or more and 1.5 or less,
The average length of roughness curve element of the first releasing layer (Rsm) is Ri der than 90 [mu] m,
The polyester resin material is a polybutylene terephthalate resin,
The mold release film whose glossiness which is the reflectance of the light in the incident angle of 60 degrees of the said 1st mold release layer is 6-150 . To the first release layer, the release film of claim 1 having a cushion layer. The release film further comprises a second release layer, the first release layer, the cushion layer, and by forming a three-layer structure laminated in the order of the second release layer according to claim 2 A release film as described in 1. The release film according to claim 2 or 3 , wherein the cushion layer is formed using a mixture of an α-olefin polymer and an α-olefin- (meth) acrylic ester copolymer. The release film according to any one of claims 1 to 4 , wherein the first release layer has a thickness of 20 µm or more and 30 µm or less. The release film according to any one of claims 1 to 5 , wherein the release film is used so as to be in contact with the surface of the coverlay film or the copper-clad laminate so that the first release layer side is in contact therewith. Disposing the release film on the object such that the first release layer of the release film according to any one of claims 1 to 6 is on the object side;
A step of performing a heat press on the object on which the release film is disposed;
Including
In the step of disposing a release film, a method for using a release film, wherein a surface of the object on which the release film is disposed is formed of a material containing a semi-cured thermosetting resin.

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